light emitting device for display and display device having the same

专利摘要:
LIGHT-EMITTING DEVICE FOR DISPLAY AND DISPLAY DEVICE HAVING THE SAME comprises a light-emitting device for a display that includes a substrate and first, second and third LED subunits, a first transparent electrode between the first and second LED subunits and in ohmic contact with the first LED subunit, a second transparent electrode between the second and third LED subunits and in ohmic contact with the second LED subunit, a third transparent electrode between the second transparent electrode and the third LED subunit and in ohmic contact with the third LED subunit, at least one current spreader connected to at least one of the first, second and third LED subunits, electrode pads arranged on the substrate and through orifice paths formed through the substrate, in which at least at least one of the through-hole paths is formed through the substrate and the first and second LED subunits.
公开号:BR112020011226A2
申请号:R112020011226-7
申请日:2018-12-04
公开日:2020-11-17
发明作者:Chang Yeon Kim；Jong Hyeon Chae；Jong Min JANG；Ho Joon Lee；Seong Gyu Jang
申请人:Seoul Viosys Co., Ltd.；
IPC主号:

专利说明:

[001] [001] Exemplary implementations of the invention generally refer to a light emitting device for a display and a display device and, more specifically, a micro light emitting device with a stacked structure and a display device with the same.
[002] [002] A light emitting diode (LED) has been widely used as an inorganic light source in various fields, such as display devices, automotive lamps and general lighting. A light-emitting diode has a longer life, lower power consumption and faster response time than an existing light source, so LEDs are rapidly replacing existing light sources.
[003] [003] Until now, conventional LEDs have been mainly used as a backlight source in a display device. However, recently, an LED display was developed that directly generates an image using light emitting diodes.
[004] [004] A display device usually emits multiple colors by mixing blue, green and red light. To generate multiple images, each pixel has blue, green and red subpixels. The color of a specific pixel is determined by the colors of the subpixels, and an image is generated by a combination of those pixels.
[005] [005] As LEDs can emit light of various colors, depending on the materials used, individual LED chips that emit blue, green and red light can be arranged in a two-dimensional plane of a display device. However, when an LED chip forms each subpixel, the number of LED chips needed to form a display device can exceed millions, thus causing an excessive amount of time for an assembly process.
[006] [006] Furthermore, as the subpixels are arranged in a two-dimensional plane, a relatively large area is occupied by a pixel, including the subpixels of blue, green and red light. Therefore, it is necessary to reduce the area of each subpixel, so that the subpixels can be formed in a limited area. However, this would cause deterioration of brightness due to the reduction of the luminous area, in addition to increasing the manufacturing complexity in the LED chip assembly process.
[007] [007] In addition, reducing the area of each subpixel would also cause deterioration in the LED's light efficiency due to the heat generated in an LED chip.
[008] [008] The information disclosed in this section is only for the understanding of the foundations of the inventive concepts and, therefore, may contain information that does not constitute the prior art.
[009] [009] Disclosure
[010] [010] Technical problem
[011] [011] Light-emitting diodes built according to the principles and some exemplary implementations of the invention and displays using them are able to enlarge an area of each subpixel without increasing the pixel area.
[012] [012] Light-emitting diodes and displays using light-emitting diodes, for example, micro LEDs, built according to the principles and some exemplary implementations of the invention are able to reduce the amount of time associated with the assembly of an emitting device light on a circuit board during manufacture.
[013] [013] Light-emitting diodes and displays using light-emitting diodes, for example, micro LEDs, built according to the principles and some exemplary implementations of the invention include one or more structures to increase the current distribution.
[014] [014] Light-emitting diodes and displays using light-emitting diodes, for example, micro LEDs, built according to the principles and some exemplary implementations of the invention include a structure to improve heat dissipation.
[015] [015] Light-emitting diodes and displays using light-emitting diodes, for example, micro LEDs, built according to the principles and some exemplary implementations of the invention include a mesh structure to improve light efficiency.
[016] [016] Additional features of the inventive concepts will be presented in the description below and, in part, will be evident from the description or can be learned by practicing the inventive concepts.
[017] [017] Technical solution
[018] [018] A light-emitting device for a display according to an exemplary embodiment includes a first LED subunit, a second LED subunit located below the first LED subunit, a third LED subunit located below the second LED subunit, and electrode pads electrically connected to the first, second and third LED subunits, in which the electrode pads include a common electrode pad electrically connected in common to the first, second and third LED subunits and the first, second and third electrodes connected at the first, second and third LED subunits, respectively, the first, second and third LED subunits are configured to be triggered independently, the light generated in the first LED subunit is configured to be emitted to the outside of the emitting device of light through the second LED subunit and the third LED subunit, and the light generated in the second subunit LED is configured to be emitted to the outside of the light emitting device through the third LED subunit.
[019] [019] The first, second and third LED subunits can include the first, second and third LED batteries configured to emit red light, green light and blue light, respectively.
[020] [020] The light emitting device may also include a first reflective electrode disposed between the electrode pads and the first LED subunit and in ohmic contact with the first LED subunit, in which the common electrode pad is connected to the first reflective electrode.
[021] [021] The first reflective electrode may include an ohmic contact layer in ohmic contact with an upper surface of the first LED subunit and a reflective layer covering at least a portion of the ohmic contact layer.
[022] [022] The first reflecting electrode can be in ohmic contact with the upper surface of the first LED subunit in a plurality of regions.
[023] [023] The light-emitting device may also include a second transparent electrode interposed between the second and third LED subunits and in ohmic contact with a lower surface of the second LED subunit and a third transparent electrode in ohmic contact with an upper surface of the third LED subunit, in which the common electrode pad is electrically connected to the second transparent electrode and the third transparent electrode.
[024] [024] The light-emitting device may further include a first layer of metal current distribution connected to a lower surface of the second transparent electrode and a third layer of metal current distribution connected to an upper surface of the third transparent electrode, in the which the common electrode pad is connected to the first layer of metal current distribution and the third layer of metal current distribution.
[025] [025] The first metal current distribution layer and the third metal current distribution layer can have a pad region to connect the common electrode pad and a projection that extends from the pad region.
[026] [026] The common electrode pad can be connected to an upper surface of the first current distribution layer and to an upper surface of the third current distribution layer.
[027] [027] The light-emitting device may also include a first color filter disposed between the third transparent electrode and the second LED subunit, in which the third layer of metal current distribution is disposed between the first color filter and the second LED subunit to be connected to the third transparent electrode through the first color filter.
[028] [028] The light-emitting device may also include a second color filter disposed between the first and the second LED subunit and a second metal current distribution layer disposed between the second color filter and the first LED subunit a be connected to the second transparent electrode through the second color filter, in which the second electrode is connected to the second metal current distribution layer.
[029] [029] The second metal current distribution layer may have a pad region to connect the second electrode pad and a projection extension portion that extends from the pad region.
[030] [030] The first and third LED subunits can each exclude a first conductivity-type semiconductor layer and a second conductivity-type semiconductor layer disposed in a partial region of the first conductivity-type semiconductor layer, and the first electrode pad and the third electrode pad can be electrically connected to the first conductivity type semiconductor layer of the first LED subunit and to the first conductivity type semiconductor layer of the third LED subunit, respectively.
[031] [031] The light-emitting device may further include a first ohmic electrode disposed in the first conductivity type semiconductor layer of the first LED subunit and a third ohmic electrode pad disposed in the first conductivity type semiconductor layer of the third LED subunit, where the first electrode is connected to the first ohmic electrode and the third electrode pad is connected to the third ohmic electrode.
[032] [032] The light-emitting device may also include a substrate connected to a bottom surface of the third LED subunit.
[033] [033] The substrate can be a sapphire substrate or a gallium nitride substrate.
[034] [034] The light-emitting device may also include an upper insulation layer disposed between the first LED subunit and the electrode pads, in which the electrode pads are electrically connected to the first, second and third LED subunits through the layer of superior insulation.
[035] [035] The top insulation layer can include at least one of a distributed Bragg reflector, an organic reflective material and a light blocking material.
[036] [036] The light emitting device can include a micro LED with a surface area less than about 10,000 µm square, the first LED subunit can be configured to emit any red, green and blue light, the second LED subunit can be configured to emit a different light of red, green and blue from the first LED subunit and the third LED subunit can be configured to emit a different light of red, green and blue from the first and second LED subunits.
[037] [037] A display device can include a circuit board and a plurality of light emitting devices arranged on the circuit board, at least one of the light emitting devices can include the light emitting device according to an exemplary embodiment, in the which the electrode pads of the light emitting devices can be electrically connected to the circuit board, the light emitting devices can also include substrates coupled to the corresponding third LED subunit and the substrates can be separated from each other.
[038] [038] A light-emitting device for a display in accordance with an exemplary embodiment includes a first LED subunit, a second LED subunit arranged in the first LED subunit, a third LED subunit arranged in the second LED subunit, electrode arranged below the first LED subunit and a padding arranged between the electrode pads, in which the electrode pads include a common electrode pad electrically connected in common to the first, second and third LED subunits and first, second and third pads of electrodes connected to the first, second and third LED subunits, respectively, the first, second and third LED subunits are independently operable, the light generated in the first LED subunit is configured to be emitted to the outside of the emitting device light through the second and third LED subunits and the light generated in the second LED subunit is configured to be in outwards through the third LED subunit.
[039] [039] The first, second and third LED subunits can include the first, second and third LED batteries configured to emit red light, green light and blue light, respectively.
[040] [040] The light emitting device may also include a first ohmic electrode in ohmic contact with a first conductive semiconductor layer of the first LED subunit and a first reflective electrode disposed between the electrode pads and the first LED subunit to be in contact ohmic with the first LED subunit, in which the first electrode is electrically connected to the first ohmic electrode and the common electrode pad is electrically connected to the first reflective electrode below the first reflective electrode.
[041] [041] The first reflective electrode may include an ohmic contact layer in ohmic contact with a second conductive semiconductor layer of the first LED subunit and a reflective layer covering at least a portion of the ohmic contact layer.
[042] [042] The first reflecting electrode may be in ohmic contact with a top surface of the first LED subunit in a plurality of regions.
[043] [043] The light-emitting device may further include a second transparent electrode interposed between the first and second LED subunits to be in ohmic contact with a lower surface of the second LED subunit, a third transparent electrode interposed between the second and third LED subunits to be in ohmic contact with a lower surface of the third LED subunit and a common connector electrically connecting the second transparent electrode and the third transparent electrode to the first reflecting electrode, in which the common connector is arranged on the first reflecting electrode and is electrically connected to the common electrode pad via the first reflective electrode.
[044] [044] The light-emitting device may also include a second layer of metal current scattering connected to a lower surface of the second transparent electrode; and a third metal current scattering layer connected to a lower surface of the third transparent electrode, in which the common connector is connected to at least one of the second transparent electrode and the second metal current scattering layer and at least one of the third transparent electrode and the third metal current scattering layer.
[045] [045] The second layer of metal chain spreading and the third layer of metal chain spreading can have a pad region to connect the common connector and a projection that extends from the pad region.
[046] [046] The common connector can be connected to an upper surface of the second layer of metal chain spreading and to an upper surface of the third layer of metal chain spreading.
[047] [047] The common connector can include a first common connector to electrically connect the second transparent electrode and the first reflective electrode to each other, and a second common connector to electrically connect the third transparent electrode and the first common connector to each other.
[048] [048] The light-emitting device may also include a first color filter disposed between the first LED subunit and the second transparent electrode and a second color filter disposed between the second LED subunit and the third transparent electrode, in which the second layer of metal current scattering is disposed between the first color filter and the first LED subunit to be connected to the second transparent electrode through the first color filter, and the third layer of metal current scattering is disposed between the second color filter and the second LED subunit to be connected to the third transparent electrode through the second color filter.
[049] [049] The light-emitting device may further include a second connector for electrically connecting the second LED subunit and the second electrode to each other and a third connector for electrically connecting the third LED subunit and the third electrode pad to each other , where each of the second and third LED subunits can include a first conductor-type semiconductor layer and a second conductor-type semiconductor layer disposed below the first conductor-type semiconductor layer, the second connector is electrically connected to the first semiconductor layer of the conductor type of the second LED subunit and the third connector is electrically connected to the first semiconductor layer of the conductor type of the third LED subunit.
[050] [050] At least one of the second connector and the third connector can come into contact with the first conductor type semiconductor layer.
[051] [051] The light-emitting device may also include a second ohmic electrode in ohmic contact with the first conductor-type semiconductor layer of the second LED subunit and a third ohmic electrode pad in ohmic contact with the first conductor-type semiconductor layer of the third LED subunit, in which the second connector is connected to the second ohmic electrode and the third connector is connected to the third ohmic electrode.
[052] [052] The second and third connectors can be connected to the upper surfaces of the second ohmic electrode and the third ohmic electrode, respectively.
[053] [053] The third connector can include a lower connector penetrating through the second LED subunit and an upper connector penetrating through the third LED subunit and connected to an intermediate connector, in which the lower connector has a pad region for connecting the connector higher.
[054] [054] The light-emitting device may also include an insulation layer covering the side surfaces of the first, second and third LED subunits, in which the insulation layer may include a distributed Bragg reflector.
[055] [055] The light-emitting device may also include connection plates located below the first LED subunit and connectors arranged on the connection plates and electrically connect the second and third LED subunits to the connection plates, respectively, on which the second electrode plate and the third electrode pad are connected to the connection electrodes, respectively, below the connection electrodes.
[056] [056] The light emitting device may also include connectors to electrically connect the second and third LED subunits to the electrode pads, in which the connectors may include materials other than the electrode pads.
[057] [057] A display device can include a circuit board and a plurality of light emitting devices arranged on the circuit board, at least one of the light emitting devices can include the light emitting device according to an exemplary embodiment, in the which the electrodes of the light-emitting device are electrically connected to the circuit board.
[058] [058] A light-emitting device for a display according to an exemplary embodiment includes a first substrate, a first LED subunit arranged under the first substrate, a second LED subunit arranged under the first LED subunit, a third subunit of LED arranged under the second LED subunit, a first transparent electrode interposed between the first and second LED subunits and in ohmic contact with a lower surface of the first LED subunit,
[059] [059] The first, second and third LED subunits can include the first, second and third LED batteries configured to emit red light, green light and blue light, respectively.
[060] [060] The light-emitting device may also include a Bragg reflector distributed between the first substrate and the first LED subunit.
[061] [061] The first substrate can include GaAs.
[062] [062] The light-emitting device may also include a second substrate disposed under the third LED subunit.
[063] [063] The second substrate can be a sapphire substrate or a GaN substrate.
[064] [064] The first LED subunit, the second LED subunit and the third LED subunit can be independently activated, the light generated from the first LED subunit can be configured to be emitted to the outside of the light emitting device through the second LED subunit, the third LED subunit and the second substrate, and the light generated from the second LED subunit can be configured to be emitted to the outside of the light emitting device through the third LED subunit and the second substrate.
[065] [065] Electrode pads can include a commonly used electrode pad electrically connected to the first, second and third LED subunits, and a first electrode pad, a second electrode pad and a third electrode pad electrically connected to the first subunit LED, the second LED subunit and the third LED subunit, respectively.
[066] [066] The common electrode pad can be electrically connected to a plurality of through-hole paths.
[067] [067] The second electrode can be electrically connected to the second LED subunit through a first through hole through the first substrate and the first LED subunit, and the third electrode pad can be electrically connected to the third LED subunit via a second orifice pathway through the first substrate, the first LED subunit and the second LED subunit.
[068] [068] The first electrode can be electrically connected to the first substrate.
[069] [069] The first electrode pad can be electrically connected to the first LED subunit through a third through hole formed through the first substrate.
[070] [070] The at least one current spreader may include a first current spreader connected to the first LED unit, a second current spreader connected to the second LED unit and a third current spreader connected to the third LED unit and the first , second and third current spreaders can be separated from the first, second and third transparent electrodes, respectively.
[071] [071] One of the electrode pads arranged on the first substrate will be electrically connected to the first, second and third transparent electrodes through a plurality of through-hole paths.
[072] [072] One of the electrode pads arranged on the first substrate can be connected to the first substrate.
[073] [073] The light emitting device may also include a first color filter disposed between the third transparent electrode and the second transparent electrode and a second color filter disposed between the second LED subunit and the first transparent electrode.
[074] [074] The first color filter and the second color filter can include layers of insulation with different refractive indices.
[075] [075] The light emitting device may include an insulation layer disposed between the first substrate and the electrode pads and covering the side surfaces of the first, second and third LED subunits.
[076] [076] The at least one current spreader may have a body that at least partially surrounds one of the via orifices and a projection that extends out of the body.
[077] [077] The body may be substantially annular in shape and the projection may be less than the diameter of the body.
[078] [078] A display device according to an exemplary embodiment includes a circuit board and a plurality of light emitting devices arranged on the circuit board, at least one of the light emitting devices includes a first substrate, a first LED subunit arranged under the first substrate, a second LED subunit arranged under the first LED subunit, a third LED subunit arranged under the second LED subunit, a first transparent electrode interposed between the first and second LED subunits and in ohmic contact with a lower surface of the first LED subunit, a second transparent electrode interposed between the second and third LED subunits, and in ohmic contact with a lower surface of the second LED subunit, a third transparent electrode interposed between the second transparent electrode and the third LED subunit, and in ohmic contact with the upper surface of the third subunit and LED, at least one current spreader connected to at least one of the first, second and third LED subunits, electrode pads arranged on the first substrate and through hole paths formed through the first substrate to electrically connect the electrode pads the first, second and third LED subunits, in which at least one of the through-hole pathways is formed through the first substrate, the first LED subunit and the second LED subunit, and the electrode pads of the light emitting device are electrically connected to the circuit board.
[079] [079] Each of the light-emitting devices may also include a second substrate disposed under the third LED subunit.
[080] [080] A light-emitting device for a display according to an exemplary embodiment includes a first substrate, a first LED subunit arranged under the first substrate, a second LED subunit arranged under the first LED subunit, a third subunit of LEDs arranged under the second LED subunit, electrode pads arranged over the first substrate, through-hole paths that pass through the first substrate to electrically connect the electrode pads to the first, second and third LED subunits and switching elements heat arranged on the first LED subunit, each exchange element having at least a portion of it disposed within the first substrate, in which at least one of the orifice pathways passes through the first substrate, the first LED subunit and the second LED subunit.
[081] [081] The first, second and third LED subunits can include first, second and third LED batteries configured to emit red light, green light and blue light, respectively, and the heat exchange elements can include heat tubes.
[082] [082] The light-emitting device may include a distributed Bragg reflector interposed between the first substrate and the first LED subunit, in which the heat exchange elements can be arranged in the distributed Bragg reflector.
[083] [083] The first substrate can include a GaAs substrate.
[084] [084] The light-emitting device may also include a second substrate disposed under the third LED subunit.
[085] [085] The second substrate can be a sapphire substrate or a GaN substrate.
[086] [086] The first LED subunit, the second LED subunit and the third LED subunit can be independently activated, the light generated from the first LED subunit can be configured to be emitted to the outside of the light emitting device through the second LED subunit, the third LED subunit and the second substrate, and the light generated from the second LED subunit can be configured to be emitted to the outside of the light emitting device through the third LED subunit and the second substrate.
[087] [087] The electrode pads can include a commonly used electrode pad electrically connected to the first, second and third LED subunits and a first electrode pad, a second electrode pad and a third electrode pad electrically connected to the first LED subunit. LED, the second LED subunit and the third LED subunit, respectively.
[088] [088] The common electrode pad can be electrically connected to a plurality of through-hole paths.
[089] [089] The second electrode can be electrically connected to the second LED subunit through a through hole through the first substrate and the first LED subunit, and the third electrode pad can be electrically connected to the third LED subunit through a through-hole path formed through the first substrate, the first LED subunit and the second LED subunit.
[090] [090] The first electrode can be electrically connected to the first substrate and the heat exchange elements can be electrically isolated from the common electrode, the second electrode and the third electrode.
[091] [091] The first electrode pad can be electrically connected to the first LED subunit through a through hole through the first substrate, and the heat exchange elements can be electrically connected to the common electrode pad and are electrically isolated from the first electrode pad.
[092] [092] The through-hole pathways can be isolated from the substrate by an insulating layer inside the substrate, and the heat exchange elements can come in contact with the substrate within the substrate.
[093] [093] The through-hole pathways and heat exchange elements can be isolated from the substrate by the insulation layer inside the substrate.
[094] [094] The light-emitting device may also include a first transparent electrode interposed between the first LED subunit and the second LED subunit, and being in ohmic contact with a lower surface of the first LED subunit, a second transparent electrode interposed between the second LED subunit and the third LED subunit, and being in ohmic contact with a lower surface of the second LED, a third transparent electrode interposed between the second transparent electrode and the third LED subunit, and being in ohmic contact with a surface top of the third LED subunit and at least one current spreader connected to at least one of the first, second and third LED subunits.
[095] [095] The at least one current spreader can include a first current spreader connected to the first LED unit, a second current spreader connected to the second LED unit and a third current spreader connected to the third LED unit and the first , second and third current spreaders can be separated from the first, second and third transparent electrodes, respectively.
[096] [096] One of the electrode pads arranged on the first substrate will be electrically connected to the first, second and third transparent electrodes through the through-hole pathways.
[097] [097] The light-emitting device may also include a first color filter disposed between the third transparent electrode and the second transparent electrode and a second color filter disposed between the second LED subunit and the first transparent electrode.
[098] [098] The light-emitting device may also include an insulating layer interposed between the first substrate and the electrode pads and covering the side surfaces of the first to the third LED subunits.
[099] [099] A light-emitting device for a display according to an exemplary embodiment includes a first substrate, a first LED subunit arranged under the first substrate, a second LED subunit arranged under the first LED subunit, a third subunit of LEDs arranged under the second LED subunit and heat exchange elements, each having at least a portion of it disposed within the first substrate, in which the heat exchange elements are arranged over the first LED subunit.
[0100] [0100] The light emitting device may also include electrode pads arranged on the first substrate and through orifice paths to electrically connect the electrode pads to the first, second and third LED subunits, in which the heat exchange elements include heat tubes.
[0101] [0101] The light-emitting device may further include a second substrate disposed under the third LED subunit, in which the first substrate may be a GaAs substrate and the second substrate may be a sapphire substrate or a GaN substrate.
[0102] [0102] The light emitting device may also include a first transparent electrode interposed between the first LED subunit and the second LED subunit, and being in ohmic contact with a lower surface of the first LED subunit, a second transparent electrode interposed between the second LED subunit and the third LED subunit, and being in ohmic contact with a lower surface of the second LED subunit, a third transparent electrode interposed between the second transparent electrode and the third LED subunit, and being in ohmic contact with an upper surface of the third LED subunit and at least one current spreader connected to at least one of the first, second and third LED subunits.
[0103] [0103] The light emitting device can include a micro LED with a surface area less than about 10,000 µm square, the first LED subunit can be configured to emit any red, green and blue light, the second LED subunit can be configured to emit a different red, green and blue light from the first LED subunit and the third LED subunit can be configured to emit a different red, green and blue light from the first and second LED subunits.
[0104] [0104] A display device can include a circuit board, at least one of the light emitting devices arranged on the circuit board, at least one of the light emitting devices can include the light emitting device according to an exemplary embodiment.
[0105] [0105] The electrode pads can be electrically connected to the circuit board.
[0106] [0106] Each of the light emitting devices may also include a second substrate disposed under the third LED subunit.
[0107] [0107] A light-emitting device for a display according to an exemplary embodiment includes a first substrate, a first LED subunit arranged under the first substrate, a second LED subunit arranged under the first LED subunit, a third subunit of LED arranged under the second LED subunit, a first ohmic electrode interposed between the first LED subunit and the second LED subunit and being in ohmic contact with a lower surface of the first LED subunit, a second ohmic electrode interposed between the second subunit LED and the third LED subunit and being in ohmic contact with a lower surface of the second LED subunit, a third ohmic electrode interposed between the second ohmic electrode and the third LED subunit and being in ohmic contact with an upper surface of the third LED subunit, the electrode pads arranged on the first substrate and the orifice pathways form through the first substrate to electrically connect the electrode pads to the first, second and third LED subunits, in which at least one of the through hole pathways is formed through the first substrate, the first LED subunit and the second LED subunit LED and at least one of the first ohmic electrode, the second ohmic electrode and the third electrode pad have a mesh structure.
[0108] [0108] The first, second and third LED subunits can include the first, second and third LED batteries configured to emit red light, green light and blue light, respectively.
[0109] [0109] The light emitting device may also include a Bragg reflector distributed between the first substrate and the first LED subunit.
[0110] [0110] The first substrate can include a GaAs substrate.
[0111] [0111] The light emitting device may also include a second substrate disposed under the third LED subunit.
[0112] [0112] The second substrate can be a sapphire substrate or a GaN substrate.
[0113] [0113] The first LED subunit, the second LED subunit and the third LED subunit can be independently activated, the light generated from the first LED subunit can be configured to be emitted to the outside of the light emitting device through the second LED subunit, the third LED subunit and the second substrate, and the light generated from the second LED subunit can be configured to be emitted to the outside of the light emitting device through the third LED subunit and the second substrate.
[0114] [0114] The electrode pads may include a commonly used electrode pad electrically connected to the first, second and third LED subunits and a first electrode pad, a second electrode pad and a third electrode pad electrically connected to the first LED subunit. LED, the second LED subunit and the third LED subunit, respectively.
[0115] [0115] The common electrode pad can be electrically connected to a plurality of through-hole paths.
[0116] [0116] The second electrode pad can be electrically connected to the second LED subunit through a through hole through the first substrate and the first LED subunit, and the third electrode pad can be electrically connected to the third LED subunit through a through hole formed through the first substrate, the first LED subunit and the second LED subunit.
[0117] [0117] The first electrode can be electrically connected to the first substrate.
[0118] [0118] The first electrode pad can be electrically connected to the first LED subunit through a through hole formed through the first substrate.
[0119] [0119] The first ohmic electrode can have the mesh structure and include Au-Zn or Au-Be, and the second ohmic electrode can have the mesh structure and include Pt or Rh.
[0120] [0120] One of the electrode pads arranged on the first substrate will be electrically connected to the first, second and third ohmic electrodes through a plurality of through-hole paths.
[0121] [0121] One of the electrode pads arranged on the first substrate can be connected to the first substrate.
[0122] [0122] The light-emitting device may further include a first color filter disposed between the third ohmic electrode and the second ohmic electrode and a second color filter disposed between the second LED subunit and the first ohmic electrode.
[0123] [0123] The first color filter and the second color filter can include layers of insulation with different refractive indices.
[0124] [0124] The light emitting device may also include an insulation layer disposed between the first substrate and the electrode pads and covering the side surfaces of the first, second and third LED subunits.
[0125] [0125] A display device can include a circuit board and a plurality of light emitting devices arranged on the circuit board, at least one of the light emitting devices can include the light emitting device according to an exemplary embodiment, in the which electrodes can be electrically connected to the circuit board.
[0126] [0126] Each of the light-emitting devices can also include a second substrate disposed under the third LED subunit.
[0127] [0127] A light-emitting device for a display according to an exemplary embodiment includes a first substrate, a first LED subunit arranged under the first substrate, a second LED subunit arranged under the first LED subunit, a third subunit of LED disposed under the second LED subunit, a first ohmic electrode interposed between the first LED subunit and the second LED subunit and being in ohmic contact with a lower surface of the first LED subunit, a second ohmic electrode interposed between the second subunit LED and the third LED subunit and being in ohmic contact with a lower surface of the second LED subunit, a third ohmic electrode interposed between the second ohmic electrode and the third LED subunit, and being in ohmic contact with an upper surface of the third LED subunit, a second substrate disposed under the third LED subunit, in which at least one of the first ohmic electrode, second ohmic electrode and third electrode pad have a mesh structure.
[0128] [0128] The first substrate can be a GaAs substrate and the second substrate can be a sapphire substrate or a GaN substrate.
[0129] [0129] It should be understood that both the general description above and the detailed description below are exemplary and explanatory and are intended to provide additional explanations of the invention as claimed.
[0130] [0130] Light-emitting diodes built according to the principles and some exemplary implementations of the invention and displays using them are able to increase an area of each subpixel without increasing the pixel area.
[0131] [0131] Light-emitting diodes and displays using light-emitting diodes, for example, micro LEDs, built according to the principles and some exemplary implementations of the invention are able to reduce the amount of time associated with the assembly of an emitting device light on a circuit board during manufacture.
[0132] [0132] Light-emitting diodes and displays using light-emitting diodes, for example, micro LEDs, built according to the principles and some exemplary implementations of the invention include one or more structures to increase the current distribution.
[0133] [0133] Light-emitting diodes and displays using light-emitting diodes, for example, micro LEDs, built according to the principles and some exemplary implementations of the invention include a structure to improve heat dissipation.
[0134] [0134] Light-emitting diodes and displays using light-emitting diodes, for example, micro LEDs, built according to the principles and some exemplary implementations of the invention include a mesh structure to improve light efficiency.
[0135] [0135] The accompanying drawings, which are included to provide an additional understanding of the invention and are incorporated and form part of this specification, illustrate exemplary embodiments of the invention and, together with the description, serve to explain the inventive concepts.
[0136] [0136] FIG. 1 is a schematic plan view of a display device according to an exemplary embodiment.
[0137] [0137] FIG. 2A is a schematic plan view of a light emitting device according to an exemplary embodiment.
[0138] [0138] FIG. 2B is a schematic cross-sectional view along a line A-A of FIG. 2A.
[0139] [0139] FIGS. 3A, 3B, 4A, 4B, 5A, 5B, 6A, 6B, 7A, 7B, 8A, 8B, 9A, 9B, 10A, 10B, 11A, 11B, 12A, 12B, 13A and 13B are schematic and section views illustrating a method of manufacturing a light emitting device according to an exemplary embodiment.
[0140] [0140] FIG. 14 is a schematic plan view of a display device according to an exemplary embodiment.
[0141] [0141] FIG. 15A is a schematic plan view of a light emitting device according to an exemplary embodiment.
[0142] [0142] FIG. 15B is a schematic cross-sectional view taken along a line A-B of FIG. 15A.
[0143] [0143] FIGS. 16A, 16B, 17A, 17B, 18A, 18B, 19A, 19B, 20A, 20B, 21A, 21B, 22A, 22B, 23A, 23B, 24A, 24B, 25A, 25B, 26A and 26B are schematic views and section views illustrating a method of manufacturing a light emitting device according to an exemplary embodiment.
[0144] [0144] FIG. 27A is a schematic plan view of a light emitting device for a display according to another exemplary embodiment.
[0145] [0145] FIG. 27B is a schematic cross-sectional view taken along a line A-B of FIG. 27A.
[0146] [0146] FIGS. 28A, 28B, 29A, 29B, 30A, 30B, 31A, 31B, 32A, 32B, 33A, 33B, 34A and 34B are schematic and cross-sectional views illustrating a method of manufacturing a light emitting device in accordance with an exemplary modality.
[0147] [0147] FIG. 35A is a plan view of a stacked LED structure according to another exemplary embodiment.
[0148] [0148] FIG. 35B is a schematic cross-sectional view taken along a line A-B of FIG. 35A.
[0149] [0149] FIG. 36A is a schematic plan view of a light emitting device in accordance with yet another exemplary embodiment.
[0150] [0150] FIGS. 36B and 36C are schematic cross-sectional views along lines G-H and I-J of FIG. 36A, respectively.
[0151] [0151] FIG. 37 is a schematic plan view of a display device according to an exemplary embodiment.
[0152] [0152] FIG. 38A is a schematic plan view of a light-emitting device for a display according to an exemplary embodiment.
[0153] [0153] FIG. 38B is a schematic cross-sectional view along a line A-A of FIG. 38A.
[0154] [0154] FIGS. 39A, 39B, 40A, 40B, 41A, 41B, 42, 43, 44, 45A, 45B, 46A, 46B, 47A, 47A, 47B, 48A, 48B, 49A and 49B are schematic plan views and cross-sectional views that illustrate a method of making a light-emitting device for a screen according to an exemplary embodiment.
[0155] [0155] FIG. 50A and FIG. 50B are a schematic plan view and a cross-sectional view of a light-emitting device for a display, according to another exemplary embodiment, respectively.
[0156] [0156] FIG. 51 is a schematic plan view of a display device according to an exemplary embodiment.
[0157] [0157] FIG. 52A is a schematic plan view of a light-emitting device for a display according to an exemplary embodiment.
[0158] [0158] FIG. 52B is a schematic cross-sectional view along a line A-A of FIG. 52A.
[0159] [0159] FIGS. 53B, 54A, 54B, 55A, 55, 56, 57, 58, 59A, 59B, 60A, 60B, 61A, 61B, 62A, 62B, 63A, 63B, 64B, 64A, 64B, 65A and 65B are schematic plan views and cross-sectional views illustrating a method of manufacturing a light-emitting device for a display, according to an exemplary modality.
[0160] [0160] FIGS. 66A and 66B are schematic plan views and cross-sectional views illustrating a light-emitting device for a display, according to another exemplary embodiment.
[0161] [0161] FIGS. 67A and 67B are a schematic plan view and a cross-sectional view of a light-emitting device according to another exemplary embodiment.
[0162] [0162] FIGS. 68A and 68B are a schematic plan view and a cross-sectional view of a light-emitting device according to another exemplary embodiment.
[0163] [0163] FIG. 69 is a schematic plan view of a display device according to an exemplary embodiment.
[0164] [0164] FIG. 70A is a schematic plan view of a light-emitting device for a display according to an exemplary embodiment.
[0165] [0165] FIG. 70B is a schematic cross-sectional view along a line A-A of FIG. 70A.
[0166] [0166] FIGS. 71A, 71B, 72A, 72B, 73A, 73B, 74, 75, 76, 77A, 77B, 78A, 78B, 79A, 47A, 79B, 80A, 80B, 81A and 81B are schematic plan views and cross-sectional views illustrating a method of making a light-emitting device for a screen according to an exemplary embodiment.
[0167] [0167] FIG. 82A and FIG. 82B are a schematic plan view and a cross-sectional view of a light-emitting device for a display, according to another exemplary embodiment, respectively.
[0168] [0168] In the following description, for the purpose of explanation, several specific details are presented, in order to provide a complete understanding of various exemplary embodiments or implementations of the invention. As used here, "modalities" and "implementations" are interchangeable words that are non-limiting examples of devices or methods that employ one or more of the inventive concepts disclosed herein. It is apparent, however, that several exemplary modalities can be practiced without these specific details or with one or more equivalent arrangements. In other cases, known structures and devices are shown in the form of a block diagram to avoid unnecessarily obscuring several exemplary modalities. In addition, several exemplary modalities may be different, but need not be exclusive. For example, forms, configurations and specific characteristics of an exemplary modality can be used or implemented in another exemplary modality without departing from inventive concepts.
[0169] [0169] Unless otherwise specified, the exemplary modalities illustrated are to be understood as providing exemplary characteristics of varying details in some ways in which inventive concepts can be implemented in practice. Therefore, unless otherwise specified, resources, components, modules, layers, films, panels, regions and / or aspects, etc. (hereinafter, individually or collectively referred to as "elements"), the various modalities can be combined in another way, separated, exchanged and / or reorganized without departing from the inventive concepts.
[0170] [0170] The use of cross hatching and / or shading in the attached drawings is generally provided to clarify the boundaries between adjacent elements. As such, neither the presence nor the absence of hatching or shading transmit or indicate any preference or requirement for materials, properties, dimensions, proportions, similarities between illustrated elements and / or any other characteristic, attribute, property, etc., of the elements , unless specified. In addition, in the attached drawings, the size and relative size of the elements may be exaggerated for reasons of clarity and / or description. When an exemplary modality can be implemented differently, a specific process order can be carried out differently from the order described. For example, two processes described consecutively can be performed at substantially the same time or performed in an order opposite to the order described. In addition, similar reference numbers indicate similar elements.
[0171] [0171] When an element such as one or layer is referred to as "above", "connected to" or "coupled to" or another element or layer, it can be directly on, connected to or coupled to another element or layer or elements or intervening layers may be present. When, however, an element or layer is referred to as "directly in", "directly connected to" or "directly coupled to" another element or layer, there are no intervening elements or layers present. Finally, the term “connected” can refer to physical, electrical and / or fluid connections, with or without intervening elements, and the D1 axis, the D2 axis and the D3 axis are not limited to three axes of a rectangular coordinates, such as x, y, and z axes, and can be interpreted in a broader sense, for example, the D1 axis, the D2 axis, and the D3 axis can be perpendicular to each other or can represent different directions that are not perpendicular to each other other for the purposes of ta disclosure, "at least one of X, Y and Z" and "at least one selected from the group consisting of X, Y and Z" can be interpreted as only X, only Y, only Z, or any combination of two or more than X, Y and Z, such as XYZ, XYY, YZ and ZZ. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.
[0172] [0172] Although the terms "first", "second" etc. can be used here to describe various types of elements, these elements should not be limited by those terms. These terms are used to distinguish one element from another element. Thus, a first element discussed below could be called a second element without departing from the teachings of disclosure.
[0173] [0173] Spatially relative terms, such as "below", "below", "under", "lower", "above", "upper", "above", "above", "highest", "lateral" ( for example, as in the "side wall"), and the like, can be used here for descriptive purposes and, thus, to describe an element related to other elements, as illustrated in the drawings. Spatially relative terms are intended to cover different orientations of a device in use, operation and / or manufacture, in addition to the orientation represented in the drawings. For example, if the device in the drawings is flipped, the elements described as "below" or "under" other elements or features will be oriented "above" the other elements or features. Thus, the exemplary term "below" can encompass an orientation above and below. In addition, the device can be otherwise oriented (for example, rotated 90 degrees or in other orientations) and, as such, the spatially relative descriptors used herein interpreted accordingly.
[0174] [0174] The terminology used in this document is intended to describe particular modalities and is not intended to be limiting. As used in this document, the singular forms "one", "one" and "o / a" are also intended to include plural forms, unless the context clearly indicates otherwise. In addition, the terms "comprises", "comprising", "includes" and / or "including", when used in this specification, specify the presence of declared resources, integers, steps,
[0175] [0175] Several exemplary modalities are described here with reference to sectional and / or exploded illustrations which are schematic illustrations of idealized exemplary modalities and / or intermediate structures. As such, variations in the shapes of the illustrations are expected as a result, for example, of manufacturing techniques and / or tolerances. Thus, exemplary modalities disclosed in this document should not necessarily be interpreted as limited to the particular illustrated shapes of the regions, but should include deviations in the shapes that result, for example, from manufacturing. In this way, the regions illustrated in the drawings may be schematic in nature and the shapes of these regions may not reflect the actual shapes of the regions of a device and, as such, are not necessarily intended to be limiting.
[0176] [0176] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meanings as those commonly understood by a specialist in the subject to which this disclosure is part. Terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning consistent with their meaning in the context of the relevant technique and should not be interpreted in an ideal or excessively formal manner unless expressly defined here.
[0177] [0177] In the following, exemplary modalities will be described in detail with respect to the attached drawings. As used herein, a light-emitting device or a light-emitting diode according to exemplary modalities may include a micro LED, which has a surface area of less than about
[0178] [0178] FIG. 1 is a schematic plan view showing a display device according to an exemplary embodiment.
[0179] [0179] Referring to FIG. 1, the display device includes a circuit board 101 and a plurality of light-emitting devices 100.
[0180] [0180] Circuit board 101 may include a circuit for passively driving the matrix or active driving the matrix. In an exemplary embodiment, circuit board 101 may include wires and resistors disposed on it. In another exemplary embodiment, circuit board 101 may include wires, transistors and capacitors. The circuit board 101 may have pads arranged on its upper surface to allow electrical connection to the circuits arranged on it.
[0181] [0181] The plurality of light-emitting devices 100 is arranged on circuit board 101. Each light-emitting device 100 can constitute a pixel. The light emitting device 100 includes electrode pads 81a, 81b, 81c and 81d electrically connected to the circuit board 101. The light emitting device 100 can include a substrate 41 disposed on an upper surface thereof. The light-emitting devices 100 are spaced apart from each other, so that the substrates 41 arranged on the upper surfaces of the light-emitting devices 100 are also spaced apart from each other.
[0182] [0182] A configuration of the light emitting device 100 according to an exemplary embodiment will be described in detail with reference to FIGS. 2A and 2B. FIG. 2A is a schematic plan view of a light emitting device 100 according to an exemplary embodiment and FIG. 2B is a cross-sectional view taken along a line A-A 'of FIG. 2A. Although electrode pads 81a, 81b, 81c and 81d are shown to be arranged on the upper side of the light emitting device 100, however, the inventive concepts are not limited to these. For example, the light-emitting device 100 can be flip-flopped on circuit board 101, and in this case, the electrode pads 81a, 81b, 81c and 81d can be arranged on the underside of the light-emitting device 100.
[0183] [0183] Referring to FIGS. 2A and 2B, the light emitting device 100 includes substrate 41, electrode pads 81a, 81b, 81c and 81d, a first battery of LED 23, a second battery of LED 33, a third battery of LED 43, a layer insulation 25, a protective layer 29, a first reflective electrode 26, a second transparent electrode 35, a third transparent electrode 45, first and third ohmic electrodes 28 and 48,
[0184] [0184] Substrate 41 can support LED stacks 23, 33 and 43. The second substrate 41 can be a growth substrate on which the third stack of LED 43 is grown. For example, substrate 41 can be a sapphire substrate or a gallium nitride substrate, in particular, a standard sapphire substrate. The first, second and third LED batteries 22, 33 and 43 are arranged on substrate 41 in the order of the third LED battery 43, the second LED battery 33 and the first LED battery 23. A single third LED battery can be arranged on a substrate 41 and thus the light emitting device 100 can have a single chip structure of a single pixel. In some exemplary embodiments, substrate 41 can be omitted, and a bottom surface of the third LED stack 43 can be exposed. In this case, a rough surface can be formed on the bottom surface of the third LED stack 43 by surface textures.
[0185] [0185] The first LED stack 23, the second LED stack 33 and the third LED stack 43 include the first semiconductor layers of conductivity type 23a, 33a and 43a, the second semiconductor layers of conductivity type 23b, 33b and 43b and the active layers interposed between the first semiconductor layers of conductivity type 23a, 33a and 43a and the second semiconductor layers of conductivity type 23b, 33b and 43b, respectively. The active layer can have a multi-quantum well structure.
[0186] [0186] According to an exemplary embodiment, the LED stack can emit light with a shorter wavelength, being placed closer to the second substrate 41. For example, the first stack of LED 23 can be an inorganic light emitting diode which emits red light, the second battery of LED 33 can be an inorganic light emitting diode, and the third battery of LED 43 can be an inorganic light emitting diode which emits blue light. The first stack of LED 23 can include a well layer based on GaInP, and the second stack of LED 33 and the third stack of LED 43 can include a well layer based on GaInN. However, inventive concepts are not limited to these. When the light emitting device 100 includes a micro LED, which has a surface area of less than about 10,000 µm square, as known in the art, or less than about 4,000 µm square or 2,500 µm square in other exemplary modalities, the first LED battery 23 can emit any red, green and blue light, and the second and third LED batteries 33 and 43 can emit a light other than red, green and blue, without adversely affecting the operation, due to the small form factor of a micro LED.
[0187] [0187] The first semiconductor layers of conductivity type 23a, 33a and 43a of the respective LED cells 23, 33 and 43 can be semiconductor layers of type n and the second semiconductor layers of conductivity type 23b, 33b and 43b of the respective batteries of LEDs 23, 33 and 43 can be p-type semiconductor layers. In the illustrated exemplary embodiment, an upper surface of the first LED stack 23 may be a semiconductor layer of type p 23b, the upper surface of the second LED stack 33 may be a semiconductor layer of type n 33a and an upper surface of the third pile of LEDs. LED 43 can be a semiconductor layer of type p 43b. More particularly, an order of the semiconductor layers can be reversed only in the second LED stack
[0188] [0188] Furthermore, in the first stack of LED 23 and the third stack of LED 43, the second semiconductor layers of conductivity type 23b and 43b can be arranged in partial regions of the first semiconductor layer of conductivity type 23a and 43a and, therefore, the first semiconductor layers of conductivity type 23a and 43a are partially exposed. Alternatively, in the case of the second LED stack 33, the first semiconductor layer of conductivity type 33a and the second semiconductor layer of conductivity type 33b can be completely overlapped.
[0189] [0189] The first stack of LED 23 is disposed in addition to substrate 41, the second stack of LED 33 is disposed below the first stack of LED 23 and the third stack of LED 43 is disposed below the second stack of LED 33. According to with an exemplary modality, since the first battery of LED 23 emits light with a wavelength greater than those of the second and third batteries of LED 33 and 43, the light generated in the first battery of LED 23 can be emitted to the outside through the second and third batteries of LED 33 and 43 and the substrate 41. Furthermore, since the second battery of LED 33 emits light with a wavelength greater than that of the third battery of LED 43, the light generated in the second LED stack 33 can be emitted outwards through the third LED stack 43 and the substrate 41.
[0190] [0190] The insulation layer 25 is arranged below the first LED stack 23 and has at least one opening exposing the second conductivity type 23b semiconductor layer of the first LED stack 23. The insulation layer 25 can have a plurality of openings widely distributed over the first LED stack 23. The insulation layer 25 can be a transparent insulation layer with a lower refractive index than that of the first LED stack 23.
[0191] [0191] The first reflective electrode 26 is in ohmic contact with the second conductive semiconductor layer 23b of the first LED stack 23 and reflects the light generated in the first LED stack 23 towards substrate 41. The first reflective electrode 26 is arranged in the insulation layer 25 and is connected to the first LED stack 23 through the opening of the insulation layer 25.
[0192] [0192] The first reflective electrode 26 may include an ohmic contact layer 26a and a reflective layer 26b. The ohmic contact layer 26a is in partial contact with the second semiconductor layer of conductivity type 23b, for example, a semiconductor layer of type p. The ohmic contact layer 26a can be formed in a limited area to prevent absorption of light by the ohmic contact layer 26a. The ohmic contact layers 26a can be formed in the second semiconductor layer of conductivity type 23b exposed in the openings of the insulation layer 25. The ohmic contact layers 26a spaced from one another can be formed in several regions of the first LED stack 23 for assist current distribution in the second semiconductor layer 23b of the conductivity type. The ohmic contact layer 26a can be formed by a transparent conductive oxide or an Au alloy, such as Au (Zn) or Au (Be).
[0193] [0193] The reflective layer 26b covers the ohmic contact layer 26a and the insulation layer 25. The reflective layer 26b covers the insulation layer 25, so that an omnidirectional reflector can be formed by a stacked structure of the first LED stack 23 with a relatively high refractive index, the insulation layer 25 with a relatively low refractive index and the reflective layer 26b. The reflective layer 26b can include a reflective metal layer, such as Al, Ag or Au. In addition, the reflective layer 26b may include an adhesive metal layer, such as Ti, Ta, Ni or Cr on the upper and lower surfaces of the reflective metal layer to improve adhesion of the reflective metal layer. Au is particularly suitable for the reflective layer 26b formed in the first LED stack 23 due to its high reflectance for red light and low reflectance for blue or green light. The reflective layer 26b can cover 50% or more of an area of the first LED stack 23 and, in some exemplary embodiments, can cover most of the first LED stack 23 to improve light efficiency.
[0194] [0194] The ohmic contact layer 26a and the reflective layer 26b can be formed by a metal layer including Au. The reflective layer 26b can be formed by a metal layer with a high reflectance for the light generated in the first LED stack 23, for example, red light. The reflective layer 26b may have a low reflectance for the light generated in the second battery of LED 33 and the third battery of LED 43, for example, green light or blue light. Therefore, the reflective layer 26b can absorb the light generated in the second and third LED batteries 33 and 43 and incidents in the reflective layer 26b to reduce or prevent optical interference.
[0195] [0195] The first ohmic electrode 28 is disposed on the first exposed conductivity semiconductor layer 23a and is in ohmic contact with the first conductivity semiconductor layer 23a. The first ohmic electrode 28 can also be formed from a metal layer including Au.
[0196] [0196] The protective layer 29 can protect the first reflective electrode 26 by covering the first reflective electrode 26. However, the protective layer 29 can expose the first ohmic electrode 28.
[0197] [0197] The second transparent electrode 35 is in ohmic contact with the second semiconductor layer of conductivity type 33b of the second LED stack 33. The second transparent electrode 35 can contact a lower surface of the second LED stack 33 between the second battery of LED 33 and the third battery of LED 43. The second transparent electrode 35 can be formed by a layer of metal or a layer of conductive oxide that is transparent to red light and green light.
[0198] [0198] The third transparent electrode 45 is in ohmic contact with the second semiconductor layer of conductivity type 43b of the third LED stack 43. The third transparent electrode 45 can be arranged between the second LED stack 33 and the third LED stack 43 and can come in contact with the top surface of the third LED stack 43. The third transparent electrode 45 can be formed by a metal layer or a conductive oxide layer that is transparent to red light and green light. The third transparent electrode 45 can also be transparent to blue light. The second transparent electrode 35 and the third transparent electrode 45 may be in ohmic contact with the p-type semiconductor layer of each LED cell to aid in current distribution. Examples of the conductive oxide layer used for the second and third transparent electrodes 35 and 45 can include SnO2, InO2, ITO, ZnO, IZO or others.
[0199] [0199] The first color filter 47 can be disposed between the third transparent electrode 45 and the second battery of LED 33 and the second color filter 67 can be disposed between the second battery of LED 33 and the first battery of LED 23. The first color filter 47 can transmit light generated in the first and second cells of LED 23 and 33 and reflect the light generated in the third cell of LED 43. The second color filter 67 can transmit light generated in the first cell of LED 23 and reflect the light generated in the second LED stack 33. Therefore, the light generated in the first LED stack
[0200] [0200] In some exemplary embodiments, the second color filter 67 can reflect the light generated in the third LED stack 43.
[0201] [0201] The first and second color filters 47 and 67 can be, for example, a low pass filter that passes only in a low frequency band, that is, a long wavelength band, a low pass filter. band that passes only a predetermined wavelength band or a band interrupt filter that blocks only a predetermined wavelength band. In particular, the first and second color filters 47 and 67 can be formed by alternately stacking layers of insulation with different refractive indices from each other, for example, they can be formed by alternately stacking layers of TiO2 and SiO2. In particular, the first and second color filters 47 and 67 can include a distributed Bragg reflector (DBR). An interrupted band of the distributed Bragg reflector can be controlled by adjusting the thicknesses of TiO2 and SiO2. The low pass filter and the band pass filter can also be formed by alternately stacking the insulation layers with different refractive indexes.
[0202] [0202] The 2-1st current distribution layer 36 can be arranged on a lower surface of the second transparent electrode 35. The 2-1st current distribution layer 36 can be electrically connected to the second semiconductor layer of conductivity type 33b of the second battery of LED 33 through the second transparent electrode 35.
[0203] [0203] The 2-2nd current distribution layer 38 can be arranged in the second color filter 67, penetrate through the second color filter 67 and be electrically connected to the first conductivity type semiconductor layer 33a of the second LED stack 33 The second color filter 67 can have an opening exposing the second battery of LED 33 and the 2-2nd current distribution layer 38 can be connected to the second battery of LED 33 through the opening of the second color filter 67.
[0204] [0204] The third current distribution layer 46 can be arranged in the first color filter 47, penetrate through the first color filter 47 and be connected to the second semiconductor layer of conductivity type 43b of the third LED stack 43. The first color filter 47 can have an opening exposing the third LED stack 43 and the third current distribution layer 46 can be connected to the third LED stack 43 through the opening of the first color filter 47.
[0205] [0205] The current distribution layers 36, 38 and 46 can be formed by a metal layer to assist in the current distribution. For example, the 2-1st current distribution layer 36 may include a pad region 36a and an extension portion 36b extending from the pad region 36a (see FIG. 4A). The 2-2nd current distribution layer 38 includes a pad region 38a and an extension portion 38b extending from the pad region 38a and the third current distribution layer 46 includes a pad region 46a and a portion extension 46b extending from pad region 46a. Pad regions 36a, 38a and 46a are regions to which electrode pads 81d and 81b can be connected and extension portions 36b, 38b and 46b can assist in current distribution. Extension portions 36b, 38b and 46b can be formed in various forms, so that a chain can be evenly distributed in the second and third cells 33 and 43.
[0206] [0206] The planarization layer 39 covers the 2-1st current distribution layer 36 below the second LED stack 33, and provides a flat surface. The planarization layer 39 can be formed by a transparent layer and can be formed by SiO2, rotation in glass (SOG) or the like.
[0207] [0207] The first link layer 49 couples the second stack of LED 33 to the third stack of LED 43. The first link layer 49 covers the first color filter 47 and is linked to the planarization layer 39. The planarization layer 39 it can also be used as a bonding layer. For example, the first bonding layer 49 and the planarization layer 39 can be a transparent organic layer or a transparent inorganic layer and be linked together. Examples of the organic layer can include SU8, poly (methylmethacrylate) (PMMA), polyimide, parylene, benzocyclobutene (BCB) or others, and examples of the inorganic layer include Al2O3, SiO2, SiNx or the like. The organic layers can be connected to a high vacuum and a high pressure, and the inorganic layers can be connected to a high vacuum when the surface energy is reduced using plasma or the like, after flattening the surfaces by, for example, a process of mechanical chemical polishing.
[0208] [0208] The second connection layer 69 couples the second battery of LED 33 to the first battery of LED 23. As illustrated in the drawing,
[0209] [0209] The upper insulation layer 71 covers side surfaces and upper regions of the first, second and third LED batteries 23, 33 and 43. The upper insulation layer 71 can be formed by SiO2, Si3N4, SOG or others. In some exemplary embodiments, the upper insulating layer 71 may include a light-reflecting material or a light-blocking material to prevent optical interference with an adjacent light-emitting device. For example, the upper insulating layer 71 may include a distributed Bragg reflector that reflects red light, green light and blue light, or a SiO2 layer with a reflective metal layer or a highly reflective organic layer deposited thereon. Alternatively, the upper insulating layer 71 may include a black epoxy, as a light blocking material, for example. A light-blocking material can prevent optical interference between light-emitting devices and increase the contrast of an image.
[0210] [0210] The upper insulation layer 71 has openings that expose the first ohmic electrode 28, the first reflective electrode 26, the third ohmic electrode 48, the 2-1st current distributor layer 36, the 2-2nd current distributor layer 38 and the third current distribution layer 46.
[0211] [0211] The electrode pads 81a, 81b, 81c and 81d are arranged above the first LED battery 23 and are electrically connected to the first, second and third LED batteries 23, 33 and 43. The electrode pads 81a, 81b, 81c and 81d are arranged in the upper insulation layer 71 and can be connected to the first ohmic electrode 28, the first reflective electrode 26, the third ohmic electrode 48, the 2-1st current distribution layer 36, the 2-2nd distribution layer current 38 and the third current distribution layer 46 exposed through the openings of the upper insulating layer 71.
[0212] [0212] For example, the first electrode pad 81a can be connected to the first ohmic electrode 28 through the opening of the upper insulation layer 71. The first electrode pad 81a can be electrically connected to the first semiconductor layer of conductivity type 23a from first LED stack 23.
[0213] [0213] The second electrode pad 81b can be connected to the 2nd 2nd current distribution layer 38 through the opening of the upper insulation layer 71. The second electrode pad 81b can be electrically connected to the first semiconductor layer of the conductivity type 33a of the second LED stack 33.
[0214] [0214] The third electrode pad 81c can be connected to the third ohmic electrode 48 through the opening of the upper insulation layer 71 and can be electrically connected to the first conductivity type semiconductor layer 43a of the third LED stack 43.
[0215] [0215] The common electrode pad 81d can be connected in common to the 2-1st current distribution layer 36, the third current distribution layer 46 and the first reflective electrode 26 through the openings. The common electrode pad 81d can be electrically connected in common to the second conductivity semiconductor layer 23b of the first LED stack 23, the second conductivity semiconductor layer 33b of the second LED stack 33 and the second conductivity semiconductor layer 43b of the third stack 43 LED
[0216] [0216] As illustrated in FIG. 2, the common electrode pad 81d can be connected to an upper surface of the third current distribution layer 46 and to an upper surface of the 2- 1st current distribution layer 36. As such, the 2-1st distribution layer current 36 can be substantially annular in shape, and the common electrode pad 81d can be connected to the third current distribution layer 46 through a central region of the 2-1st current distribution layer 36
[0217] [0217] According to the illustrated example, the first LED battery 23 is electrically connected to the electrode pads 81d and 81a, the second LED battery 33 is electrically connected to the electrode pads 81d and 81b and the third LED battery 43 is electrically connected to the electrode pads 81d and 81c. As such, the anodes of the first LED 23 battery, the second LED 33 battery and the third LED 43 battery are electrically connected in common to the electrode pad 81d and the cathodes of the first LED battery 23, the second LED battery 33 and the third LED stack 43 is electrically connected to the first, second and third electrode pads 81a, 81b and 81c, respectively. In this way, the first, second and third LED batteries 23, 33 and 43 can be activated independently.
[0218] [0218] FIGS. 3A, 3B, 4A, 4B, 5A, 5B, 6A, 6B, 7A, 7B, 8A, 8B, 9A, 9B, 10A, 10B, 11A, 11B, 12A, 12B, 13A and 13B are schematic views and section views illustrating a method of manufacturing a light emitting device 100 according to an exemplary embodiment. In the drawings, each plan view is illustrated corresponding to a plan view of FIG. 1, and each cross-sectional view (except FIG. 4B) is taken along line A-A of the corresponding plan view. FIG. 4B is a cross-sectional view taken along line B-B of FIG. 4A.
[0219] [0219] Referring to FIGS. 3A and 3B, the first LED stack 23 is grown on a first substrate 21. The first substrate 21 can be, for example, a GaAs substrate. The first LED stack can be formed by semiconductor layers based on AlGaInP and includes the first semiconductor layer of conductivity type 23a, the active layer and the second semiconductor layer of conductivity type 23b. The first type of conductivity can be type n and the second type of conductivity can be type p.
[0220] [0220] The insulation layer 25 is formed in the first LED stack 23, and the openings can be formed in it by standardizing the insulation layer 25. For example, SiO2 is formed in the first LED stack 23, a photoresistor is applied to the SiO2 and a photoresistor pattern is then formed using photolithography and development. Then, SiO2 can be standardized using the photoresistor pattern as an etching mask to form the insulation layer 25 that has the openings.
[0221] [0221] Then, the ohmic contact layer 26a is formed in the openings of the insulation layer 25. The ohmic contact layer 26a can be formed by lifting technology or the like. After the formation of the ohmic contact layer 26a, the reflective layer 26b covering the ohmic contact layer 26a and the insulating layer 25 is formed. The reflective layer 26b can be formed, for example, by Au, and can be formed using a lifting technique or the like. The first reflective electrode 26 can be formed by the ohmic contact layer 26a and the reflective layer 26b.
[0222] [0222] The first reflecting electrode 26 may have a shape in which four corner portions are removed from a rectangular region of the light emitting device, as illustrated in the drawing. The ohmic contact layers 26a can be widely distributed in a lower portion of the first reflective electrode 26. While FIGS. 3A and 3B show a region of the light emitting device, a plurality of regions of the light emitting device can be provided on the substrate 21 and the first reflecting electrode 26 can be formed in each region of the light emitting device.
[0223] [0223] The protective layer 29 can cover the first reflective electrode 26. The protective layer 29 can protect the first reflective electrode 26 from an external environment. The protective layer 29 can be formed, for example, by SiO2, Si3N4, SOG or others.
[0224] [0224] Then, the protective layer 29 and the second semiconductor layer of conductivity type 23b can be etched to expose the first semiconductor layer of conductivity type 23a and the first ohmic contact layer 28 is formed in the first semiconductor layer 23a of type of exposed conductivity. The first ohmic electrode 28 is in ohmic contact with the first semiconductor layer of conductivity type 23a.
[0225] [0225] Referring to FIGS. 4A and 4B, the second stack of LED 33 is grown on a second substrate 31 and the second transparent electrode 35 is formed on the second stack of LED 33. The second stack of LED 33 can be formed by semiconductor layers based on gallium nitride and it may include the first conductivity-type semiconductor layer 33a, the active layer and the second conductivity-type semiconductor layer 33b. The active layer can include a GaInN well layer. The first type of conductivity can be type n and the second type of conductivity can be type p.
[0226] [0226] The second substrate 31 is a substrate on which a semiconductor layer based on gallium nitride can be grown and can be different from the first substrate 21. A composition ratio of the GaInN well layer can be determined so that the second LED battery 33 can emit green light, for example. The second transparent electrode 35 is in ohmic contact with the second semiconductor layer of conductivity type 33b.
[0227] [0227] The 2-1st current distribution layer 36 is formed on the second transparent electrode 35. The 2-1st current distribution layer 36 can be formed by a metal layer. The 2-1st current distribution layer 36 can include the pad region 36a and the extension portion 36b. The pad region 36a can have an opening 36h having a substantially annular shape and exposing the second transparent electrode 35. The extension portion 36b extends from the pad region 36a and can extend substantially in a diagonal direction, as illustrated in the drawing, but it is not limited to it. Extension portion 36b can take various forms. Although FIGS. 4A and 4B show a light-emitting device region, a plurality of light-emitting device regions can be provided on substrate 31, and the 2-1st current distribution layer 36 can be formed in each region of the light-emitting device. .
[0228] [0228] The planarization layer 39 covering the 2-1st current distribution layer 36 and the second transparent electrode 35 is formed. The planarization layer 39 provides a flat surface in the 2-1st current distribution layer 36. The planarization layer 39 can be formed by a light transmitting SOG, or the like, and the planarization layer 39 can be used as a layer binding.
[0229] [0229] Referring to FIGS. 5A and 5B, the third LED stack 43 is grown on a third substrate 41 and the third transparent electrode 45 and the first color filter 47 are formed on the third LED stack 43. The third LED stack 43 can be formed by layers semiconductors based on gallium nitride and may include the first conductivity semiconductor layer 43a, the active layer and the second conductivity semiconductor layer 43b. The active layer can also include a GaInN well layer. The first type of conductivity can be type n and the second type of conductivity can be type p.
[0230] [0230] The third substrate 41 is a substrate on which a semiconductor layer based on gallium nitride can be grown and can be different from the first substrate 21. A proportion of GaInN composition can be determined so that the third LED stack 43 emit blue light, for example. The third transparent electrode 45 is in ohmic contact with the second semiconductor layer of conductivity type 43b.
[0231] [0231] Since the first color filter 47 is substantially the same as that described with reference to FIGS.
[0232] [0232] The first color filter 47 can be standardized to form openings 47a, 47b and 47c exposing the third transparent electrode 45. In addition, the third transparent electrode 45 and the second semiconductor layer of conductivity type 43b exposed in the opening 47a can be sequentially standardized to expose the first conductivity type 43a semiconductor layer.
[0233] [0233] The third ohmic electrode 48 is formed in the first exposed semiconductor layer of the conductivity type 43a and the third current distribution layer 46 is formed. The third current distribution layer 46 is in contact with the third transparent electrode 45 through openings 47b and 47c. The third current distribution layer 46 may include the pad region 46a and the extension portion 46b. The pad region 46a can be in contact with the third transparent electrode 45 through the opening 47b and the extension portion 46b can be in contact with the third transparent electrode 46 through the opening 47c. The third current distribution layer 46 and the third ohmic electrode 48 may include the same material, such as metal.
[0234] [0234] The planarization layer or the first connection layer 49 is formed in the third current distribution layer 46 and the third ohmic electrode 48. The first connection layer 49 can be formed by light transmitting SOG.
[0235] [0235] Referring to FIGS. 6A and 6B, the first LED stack 23 of FIGS. 3A and 3B is connected to a carrier substrate 51. The first stack of LED 23 can be connected to the carrier substrate 51 through an adhesive layer 53. In particular,
[0236] [0236] Next, manufacturing processes for a light emitting device, coupling the first, second and third LED batteries 23, 33 and 43 manufactured by the above processes to each other, and standardizing the first, second and third LED batteries 23 , 33, and 43 will be described.
[0237] [0237] Referring to FIGS. 7A and 7B, the second LED stack 33 of FIGS. 4A and 4B are connected to the third LED stack 43 of FIGS. 5A and 5B.
[0238] [0238] The first connection layer 49 and the planarization layer 39 are arranged facing each other to align the third current distribution layer 46 and the 2- first current distribution layer 36. In particular, a portion center of the pad region 36a of the 2-1st current distribution layer 36 is aligned above the pad region 46a of the third current distribution layer 46.
[0239] [0239] Then, the second substrate 31 is removed from the second stack of LED 33 by a technique, such as laser removal, chemical removal or others. As such, the first semiconductor layer of conductivity type 33a of the second LED stack 33 is exposed from the above. In some exemplary embodiments, a surface of the first semiconductor layer 33a of the exposed conductivity type can be textured.
[0240] [0240] Referring to FIGS. 8A and 8B, the second color filter 67 is formed on the first semiconductor layer 33a of the exposed conductivity type. Since the second color filter 67 is substantially the same as that described with reference to FIGS. 2A and 2B, detailed descriptions will be omitted to avoid redundancy.
[0241] [0241] Then, the second color filter 67 can be standardized to form openings exposing the second stack of LED 33, and the 2-2nd current distribution layer 38 is formed on the second color filter 67. The 2-2nd current distribution layer 38 is formed to correspond to each region of the light emitting device and includes the pad region 38a and the extension portion 38b extending from the pad region 38a. A specific shape of the extension portion 38b is not particularly limited and may have various shapes for distributing current in the second LED stack 33.
[0242] [0242] Next, the second connection layer 69 covers the 2- 2nd current distribution layer 38 and the second color filter 67. The second connection layer 69 can be a light-transmitting organic layer or inorganic layer. As such, a flat surface can be provided on an upper surface of the second LED stack 33.
[0243] [0243] Then, with reference to FIGS. 9A and 9B, the first LED stack 23 of FIGS. 6A and 6B are connected to the second LED stack 33. The first semiconductor layer of the conductivity type 23a exposed from the first LED stack 23 can be connected to the second link layer 69. Alternatively, another planarization layer can be formed additionally on the first semiconductor layer of conductivity type 23a, and the other planarization layer and the second connection layer 69 can be connected to each other.
[0244] [0244] Then, the carrier substrate 51 and the adhesive layer 53 are removed. As such, the protective layer 29 and the first ohmic electrode 28 can be exposed.
[0245] [0245] Referring to FIGS. 10A and 10B, the protective layer 29 and the insulation layer 25 can be standardized, so that the first LED stack 23 is exposed around the first reflective electrode 26 and the first LED stack 23 and the second connection layer 69 can be sequentially standardized, so that the 2-2nd current distribution layer 38 is exposed. In addition, the second color filter 67 can be exposed around the first reflective electrode 26. The pad region 38a and the extension portion 36b of the 2-2nd current distribution layer 38 can be partially exposed.
[0246] [0246] Meanwhile, a portion of the first semiconductor layer of conductivity type 23a, in which the first ohmic electrode 28 is disposed in a corner portion of the region of the light-emitting device, may remain.
[0247] [0247] Referring to FIGS. 11A and 11B, the second color filter 67, the second LED stack 33, the second transparent electrode 35, the planarization layer 39, the first connection layer 49 can be sequentially standardized, so that the third distribution layer of current 46 and the third ohmic electrode 48 are exposed. In addition, the pad region 36a of the 2- 1st current distribution layer 36 is exposed and a through hole that penetrates through a central portion of the pad region 36a is formed.
[0248] [0248] Through holes that expose the third current distribution layer 46 and the third ohmic electrode 48 can be formed. The second color filter 67, the second stack of LED 33, the second transparent electrode 35, the planarization layer 39 and the first connection layer 49 are removed sequentially in edge portions of the regions of the light-emitting device and the third electrode transparent 45 and the third LED stack 43 is removed, so that an upper surface of substrate 41 can be exposed. The exposed region of substrate 41 can be a dicing region for cutting substrate 41 into multiple light emitting devices.
[0249] [0249] Although the third current distribution layer 46 and the third ohmic electrode 48 are described as exposed through the through holes, in some exemplary embodiments, the second color filter 67, the second LED stack 33, the second electrode transparent 35, the planarization layer 39, and the first connection layer 49 arranged around the first reflective electrode 26 can be removed sequentially, and the third current distribution layer 46 and the third ohmic electrode 48 can thus be arranged adjacent to a side surface of the second LED stack 33.
[0250] [0250] Referring to FIGS. 12A and 12B, the upper insulation layer 71 is formed to cover the side surfaces and upper regions of the first, second and third LED cells 23, 33 and 43. The upper insulation layer 71 can be formed of a single layer or multiple layers of SiO2, Si3N4, SOG or others. Alternatively, the upper insulating layer 71 may include a distributed Bragg reflector formed by an alternate deposit of SiO2 and TiO2.
[0251] [0251] Then, the top insulation layer 71 is standardized using photolithography and engraving techniques to form openings 71a, 71b, 71c, 71d and 71e. The opening 71a exposes the third current distribution layer 46 and the 2-1st current distribution layer 36. The opening 71b exposes the first reflective electrode 26. The opening 71a and the opening 71b can be arranged adjacent to each other. In addition, the first reflective electrode 26 can be exposed through a plurality of openings 71.
[0252] [0252] Opening 71c exposes the first ohmic electrode 28, opening 71d exposes the 2-2nd current distribution layer 38 and opening 71e exposes the third ohmic electrode 48.
[0253] [0253] The top insulation layer 71 can be removed at one edge of the region of the light emitting device. As such, the upper surface of the substrate 41 can be exposed in the dicing region.
[0254] [0254] Referring to FIGS. 13A and 13B, electrode pads 81a, 81b, 81c and 81d are formed in the upper insulation layer 71. Electrode pads 81a, 81b, 81c and 81d include the first electrode pad 81a, the second electrode pad 81b, the third electrode pad 81c and the common electrode pad 81d.
[0255] [0255] The common electrode pad 81d is connected to the 2-1st current distribution layer 36 and the third current distribution layer 46 through opening 71a, and is connected to the first reflective electrode 26 through opening 71b. As such, the common electrode pad 81d is electrically connected in common to the anodes of the first, second and third LED batteries 23, 33 and 43.
[0256] [0256] The first electrode pad 81a is connected to the first ohmic electrode 28 through opening 71c, to be electrically connected to the cathode of the first LED stack 23, for example, the first semiconductor layer of conductivity type 23a. The second electrode pad 81b is connected to the 2-2nd current distribution layer 38 through the opening
[0257] [0257] The electrode pads 81a, 81b, 81c and 81d are electrically separated from each other, so that each of the first, second and third LED batteries 23, 33 and 43 is electrically connected to two electrode pads to be independently triggered.
[0258] [0258] Then, the light emitting device 100 can be formed by dividing substrate 41 into several regions of the light emitting device. As illustrated in FIG. 13A, electrode pads 81a, 81b, 81c and 81d can be arranged at four corners of each light emitting device 100. In addition, electrode pads 81a, 81b, 81c and 81d can be substantially rectangular in shape, but the inventive concepts are not limited to them.
[0259] [0259] Although substrate 41 is described as being divided, in some exemplary embodiments, substrate 41 can be removed and the surface of the first exposed conductivity type 43a semiconductor layer can therefore be textured. The substrate 41 can be removed after the first stack of LED 23 is connected to the second stack of LED 33 or it can be removed after the formation of the electrode pads 81a, 81b, 81c and 81d.
[0260] [0260] According to the exemplary modalities, a light emitting device includes the first, second and third LED batteries 23, 33 and 43, in which the anodes of the LED batteries are electrically connected in common, and their cathodes are connected independently. However, the inventive concepts are not limited to them, and the anodes of the first, second and third LED batteries 23, 33 and 43 can be connected independently to the electrodes, and their cathodes can be electrically connected in common.
[0261] [0261] The light emitting device 100 can include the first, second and third LED batteries 23, 33 and 43 to emit red, green and blue light and therefore can be used as a single pixel on a display device. As described with reference to FIG. 1, a display device may be provided by arranging a plurality of light emitting devices 100 on circuit board 101. Since the light emitting device 100 includes the first, second and third LED cells 23, 33 and 43, a subpixel area in a pixel can be increased. In addition, the first, second and third LED batteries 23, 33 and 43 can be mounted by mounting a light-emitting device 100, thereby reducing the number of assembly processes.
[0262] [0262] As described with reference to FIG. 1, the light-emitting devices 100 mounted on the circuit board 101 can be driven by a passive matrix method or an active matrix method.
[0263] [0263] FIG. 14 is a schematic plan view of a display device according to an exemplary embodiment.
[0264] [0264] Referring to FIG. 14, the display device includes a circuit board 201 and a plurality of light emitting devices 200.
[0265] [0265] Circuit board 201 may include a circuit for passively driving the matrix or active driving the matrix. In an exemplary embodiment, circuit board 201 may include wires and resistors disposed on it. In another exemplary embodiment, circuit board 201 may include wires, transistors and capacitors. Circuit board 201 may have pads arranged on its upper surface to allow electrical connection to the circuits arranged on it.
[0266] [0266] The plurality of light-emitting devices 200 are arranged on circuit board 201. Each light-emitting device 200 can constitute a pixel. The light emitting device 200 has impact pads 251a, 251b, 251c and 251d, and the protection blocks 251a, 251b, 251c and 251d are electrically connected to circuit board 201. The light emitting devices 200 are arranged on the circuit 201 as separate chips and are spaced from each other. An upper surface of each light emitting device 200 may be a surface of a LED stack 243, for example, a surface of a n-type semiconductor layer. In addition, the surface of the LED stack 243 may include a rough surface formed by a surface texture. However, in some exemplary embodiments, the surface of the LED stack 243 can be covered with a light-transmitting insulation layer.
[0267] [0267] A specific configuration of the light emitting device 200 will be described in detail with reference to FIGS. 15A and 15B. In addition, a light emitting device 2000 of FIGS. 27A and 27B, or a light emitting device 2001 of FIGS. 36A and 36B can also be arranged on circuit board 201 instead of light emitting device 200.
[0268] [0268] FIG. 15A is a schematic plan view of a light emitting device 200 according to an exemplary embodiment and FIG. 15B is a cross-sectional view taken along line A-B of FIG. 15A.
[0269] [0269] Referring to FIGS. 15A and 15B, the light emitting device 200 may include impact pads 251a, 251b, 251c and 251d, a filler 253, a first stack of LED 223, a second stack of LED 233, a third stack of LED 243, insulation layers 225, 229, 261 and 271, a first reflective electrode 226, a second transparent electrode 235, a third transparent electrode 245, first, second and third ohmic electrodes 228a, 238 and 248, connection pads 228b and 228c, one second current spreading layer 236, third current spreading layer 246, first color filter 237, second color filter 247, first connection layer 239, second connection layer 269 and connectors 268b, 268c, 268d, 278c and 278d.
[0270] [0270] The impact pads (or electrode pads) 251a, 251b, 251c and 251d and padding material 253 are arranged below the first LED stack 223 and support the first, second and third LED batteries 223, 233 and 243. Impact pads 251a, 251b, 251c and 251d may include metals, such as copper (Cu), titanium (Ti), nickel (Ni), tantalum (Ta), platinum (Pt), palladium (Pd), chrome ( Cr) or others. In some exemplary embodiments, a multilayer solder barrier layer can be formed on the top surface of the impact pad, and a gold (Au) or silver (Ag) surface layer can be provided on an impact pad surface to improve the “wettability” of the weld. The filling material 253 is formed by an insulating material. Since the impact pads 251a, 251b, 251c and 251d and the filler material 253 can function as a support structure, a separate support substrate can be omitted. An electrical connection of the impact pads 251a, 251b, 251c and 251d will be described in detail below.
[0271] [0271] The LED batteries are arranged in the order of the first LED battery 223, the second LED battery 233 and the third LED battery 243 on impact pads 251a, 251b, 251c and 251d. The first to third LED batteries 223, 233 and 243 can be stacked sequentially on top of each other and thus the light emitting device 200 has a single, single pixel chip structure.
[0272] [0272] The first LED stack 223, the second LED stack 233 and the third LED stack 243 include the first semiconductor layers of the conductivity type 223a, 233a and 243a, the semiconductor layers of the second conductivity type 223b, 233b and 243b and the active layers interposed between the first semiconductor layers of the conductivity type 223a, 233a and 243a and the second semiconductor layers of the conductivity type 223b, 233b and 243b, respectively. In particular, the active layer can have a multiple quantum well structure. As illustrated, the second semiconductor layers of conductor type 223b, 233b and 243b are arranged below some regions of the first semiconductor layers of conductor type 223a, 233a and 243a, respectively, and therefore the lower surfaces of the first semiconductor layers of conductor type 223a , 233a and 243a are partially exposed.
[0273] [0273] The first to third batteries of LEDs 222, 233 and 243 can emit light with a longer wavelength, as they are arranged closer to the impact pads 251a, 251b, 251c and 251d. For example, the first stack of LED 223 can be an inorganic light emitting diode that emits red light, the second stack of LED 233 can be an inorganic light emitting diode that emits green light and the third stack of LED 243 can be a inorganic LED emitting blue light. The first LED stack 223 can include a GaInP based well layer, and the second LED stack 233 and the third LED stack 243 can include a GaInN based well layer. However, inventive concepts are not limited to these. When the light emitting device 200 includes a micro LED, which has a surface area of less than about 10,000 µm square, as known in the art, or less than about
[0274] [0274] Since the first battery of LED 223 can emit light with a wavelength greater than that of the second and third batteries of LED 233 and 243, the light generated in the first battery of LED 223 can be emitted to the outside through of the second and third LED batteries 233 and 243 and the substrate 241. Furthermore, since the second LED battery 233 can emit light with a wavelength greater than that of the third LED battery 243, the light generated in the second LED stack 233 can be emitted outwards through the third LED stack 243 and the substrate 241.
[0275] [0275] In addition, the first semiconductor layers of conductivity type 223a, 233a and 243a of the respective LED cells 223, 233 and 243 can be semiconductor layers of type n and the second semiconductor layers of conductivity type 223b, 233b and 243b of the respective cells LEDs 223, 233 and 243 can be p-type semiconductor layers. In the exemplary embodiment illustrated, an upper surface of the first LED stack 223 is a semiconductor layer of type 223b, an upper surface of the second LED stack 233 is a semiconductor layer of type 233a and an upper surface of the third LED stack 243 is a semiconductor layer of type n 243b. In an exemplary embodiment, the first LED stack 223, the second LED stack 233 and the third LED stack 243 can have the first semiconductor layers of conductivity type 223a, 233a and 243a with textured surfaces, respectively, to improve efficiency light extraction. However, when the second 233 LED battery emits green light, since the green light has greater visibility than the red or blue light, it is preferable to increase the luminous efficiency of the first 223 LED battery and the third LED battery. LED 243 greater than that of the second 233 LED stack. As such, luminous intensities of red light, green light and blue light can be adjusted to be substantially uniform by applying surface textures to a greater extent on the first LED stack 223 and the third battery LED 243 than in the second 233 LED stack.
[0276] [0276] The insulation layer 225 is arranged below the first LED stack 223 and has at least one opening exposing the second conductivity type semiconductor layer 223b of the first LED stack 223. The insulation layer 225 can have a plurality of openings widely distributed over the first 223 LED stack. The insulation layer 225 may be a transparent insulation layer with a lower refractive index than that of the first 223 LED stack.
[0277] [0277] The first reflective electrode 226 is in ohmic contact with the second semiconductor layer of conductivity type 223b of the first LED stack 223 and reflects the light generated in the first LED stack 223 towards the second LED stack 233. The first reflective electrode 226 is disposed in the insulation layer 225 and is connected to the first LED stack 223 through the openings in the insulation layer 225.
[0278] [0278] The first reflective electrode 226 may include an ohmic contact layer 226a and a reflective layer 226b. The ohmic contact layer 226a is in partial contact with the second semiconductor layer of conductivity type 223b, for example, a semiconductor layer of type p. The ohmic contact layer 226a can be formed in a limited area to prevent the absorption of light by the ohmic contact layer 226a. The ohmic contact layers 226a can be formed in the second semiconductor layer of conductivity type 223b exposed in the openings of the insulation layer 225. The ohmic contact layers 226a spaced from each other are formed in a plurality of regions in the first LED stack 223 to assist the distribution of current in the second semiconductor layer of conductivity type 223b. The ohmic contact layer 226a can be formed by a transparent conductive oxide or an Au alloy such as Au (Zn) or Au (Be).
[0279] [0279] The reflective layer 226b covers the ohmic contact layer 226a and the insulating layer 225. The reflective layer 226b covers the insulating layer 225, so that an omnidirectional reflector can be formed by a stacked structure of the first LED stack. 223 with a relatively high refractive index, and the insulation layer 225 and the reflective layer 226b with a relatively low refractive index. The reflective layer 226b may include a reflective metallic layer,
[0280] [0280] The reflective layer 226b can be formed by a metal layer with a high reflectance for the light generated in the first LED stack 223, for example, red light. The reflective layer 226b may have a relatively low reflectance for the light generated in the second LED stack 233 and the third LED stack 243, for example, green light or blue light. Therefore, the reflective layer 226b can absorb the light generated in the second and third LED batteries 233 and 243 and incidents in the reflective layer 226b to decrease optical interference.
[0281] [0281] The first ohmic electrode 228a is disposed on the first exposed conductivity semiconductor layer 223a and is in ohmic contact with the first conductivity semiconductor layer 223a. The first ohmic electrode 228a can be disposed between the first conductive-type semiconductor layer 223a and the first impact pad 251a, as illustrated in FIG. 15B. The first ohmic electrode 228a can also be formed from a metal layer containing Au.
[0282] [0282] The connection pads 228b and 228c can be formed together when the first reflective electrode 226 is formed, but the inventive concepts are not limited to these. For example, connection pads 228b and 228c can be formed together when the first ohmic electrode 228a is formed, or through a process separate from the processes mentioned above.
[0283] [0283] The connection pads 228b and 228c are electrically isolated from the first reflective electrode 226 and the first ohmic electrode 228a. For example, connection pads 228b and 228c can be arranged below insulation layer 225 and isolated from the first LED stack 223.
[0284] [0284] Insulation layer 229 covers the first reflective electrode 226 to separate the first reflective electrode 226 from the impact pads 251a, 251b, 251c and 251d. The insulation layer 229 includes openings 229a, 229b, 229c and 229d. Opening 229a exposes the first ohmic electrode 228a, opening 229b exposes connection pad 228b, opening 229c exposes connection pad 29c and opening 229d exposes the first reflective electrode 226.
[0285] [0285] An insulating layer 229 material may be SiO2, Si3N4, SOG or the like, but is not limited to these, and may include light-transmitting or non-light-transmitting material.
[0286] [0286] The second transparent electrode 235 is in ohmic contact with the second semiconductor layer of conductivity type 233b of the second LED battery 233. As illustrated in the drawing, the second transparent electrode 235 is in contact with a lower surface of the second battery of LEDs. LED 233 between the first battery of LED 223 and the second battery of LED 233. The second transparent electrode 235 can be formed by a metal layer or a layer of conductive oxide that is transparent to red light. The second transparent electrode 235 can also be transparent to green light.
[0287] [0287] The third transparent electrode 245 is in ohmic contact with the second semiconductor layer of conductivity type 243b of the third LED stack 243. The third transparent electrode 245 can be arranged between the second LED stack 233 and the third LED stack 243 and is in contact with a lower surface of the third LED stack 243. The third transparent electrode 245 can be formed by a metal layer or a conductive oxide layer that is transparent to red light and green light. The third transparent electrode 245 can also be transparent to blue light. The second transparent electrode 235 and the third transparent electrode 245 may be in ohmic contact with the p-type semiconductor layer of each LED cell to aid in current distribution. Examples of the conductive oxide layer used for the second and third transparent electrodes 235 and 245 can include SnO2, InO2, ITO, ZnO, IZO or others.
[0288] [0288] The first color filter 237 can be disposed between the second transparent electrode 235 and the first battery of LED 223 and the second color filter 247 can be disposed between the second battery of LED 233 and the third battery of LED 243. The first color filter 237 transmits light generated in the first LED stack 223 and reflects the light generated in the second LED stack
[0289] [0289] In some exemplary embodiments, the first color filter 237 can also reflect the light generated in the third LED stack 243.
[0290] [0290] The first and second color filters 237 and 247 can be, for example, a low pass filter that passes only in a low frequency band, that is, a long wavelength band, a low pass filter. band that passes only a predetermined wavelength band or a band interrupt filter that blocks only a predetermined wavelength band. In particular, the first and second color filters 237 and 247 can be formed by alternating stacking of insulation layers with different refractive indexes and, for example, can be formed by alternating stacking of TiO2 and SiO2 insulation layers. , insulation layers of Ta2O5 and SiO2, insulation layers of Nb2O5 and SiO2, insulation layers of HfO2 and SiO2 or insulation layers of ZrO2 and SiO2. In particular, the first and second color filters 237 and 247 can include a distributed Bragg reflector (DBR). An interruption band of the distributed Bragg reflector can be controlled by adjusting the thicknesses of TiO2 and SiO2. The low-pass filter and the band-pass filter can also be formed by layers of insulation stacked alternately with different refractive indices.
[0291] [0291] The second current spread layer 236 can be electrically connected to the second semiconductor layer of conductivity type 233b of the second LED stack 233 through the second transparent electrode 235. The second current spread layer 236 can be arranged on the bottom surface of the first color filter 237 and connected to the second transparent electrode 235 through the first color filter 237. The first color filter 237 can have an opening exposing the second LED stack 233 and the second current spread layer 236 can be connected to the second transparent electrode 235 through the opening of the first color filter 237.
[0292] [0292] The second current spread layer 236 may include a pad region 236a and an extension 236b extending from the pad region 236a (see FIGS. 17A and 11B). In addition, the pad region 236a can substantially have a ring shape including a hollow portion. FIG. 17A shows the extension 236b being extended in a diagonal direction from the light emitting device 200, but the inventive concepts are limited to this, and the extension 236b can take various forms.
[0293] [0293] The second current spreading layer 236 is formed by a metal layer with a foil resistance lower than that of the second transparent electrode 235 and therefore assists the distribution of current in the second 233 LED stack. second current spread layer 236 is disposed below the first color filter 237, so that the first color filter 237 reflects the light generated in the second LED stack 233 and traveling towards the second current spread layer 236 to avoid the loss of light.
[0294] [0294] The second ohmic electrode 238 is in ohmic contact with the exposed bottom surface of the first semiconductor layer of conductivity type 233a. The second ohmic electrode 238 can be substantially ring-shaped with a hollow portion (see FIG. 17A). In some exemplary embodiment, the second ohmic electrode 238 may include an extension along with a current distribution pad region. The first color filter 237 can cover the first conductor-type semiconductor layer 233a around the second ohmic electrode 238.
[0295] [0295] The third current spread layer 246 can be electrically connected to the second semiconductor layer of conductivity type 243b from the third LED stack 243 through the third transparent electrode 245. The third current spread layer 246 can be arranged on the bottom surface of the second color filter 247 and connected to the third transparent electrode 245 through the second color filter 247. The second color filter 247 can have an opening exposing the third LED stack 243 and the third current spread layer 246 can be connected to the third transparent electrode 245 through the opening of the second color filter 247.
[0296] [0296] The third current spread layer 246 may include a pad region 246a and an extension 246b extending from pad region 246a (see FIGS. 18A and 18B). In addition, the pad region 246a can substantially have a ring shape including a hollow portion. FIG. 18A shows the extension 246b as being extended along an edge on one side of the light emitting device 200, but the inventive concepts are not limited to this, and the extension 246b can take various forms.
[0297] [0297] The third current spreading layer 246 is formed by a metal layer with a foil resistance lower than that of the third transparent electrode 245 and therefore assists the distribution of current in the third LED stack 243. The third layer of current spread 246 is arranged below the second color filter 247, so that the second color filter 247 reflects the light generated in the third LED stack 243 and traveling towards the third current spread layer 246 to prevent loss of light.
[0298] [0298] The third ohmic electrode 248 is in ohmic contact with the exposed bottom surface of the first semiconductor layer of conductivity type 243a. The third ohmic electrode 248 can be substantially ring-shaped having a hollow portion. In some exemplary embodiments, the third ohmic electrode 248 may include an extension along with a current distribution pad region. The second color filter 247 can cover the first semiconductor layer of conductor type 243a around the third ohmic electrode 248.
[0299] [0299] The first link layer 239 couples the second LED stack 233 to the first LED stack 223. The first link layer 239 can connect the first LED stack 223 and the first color filter 238 to each other. The first bonding layer 239 can be formed by a transparent organic layer or it can be formed by a transparent inorganic layer. Examples of the organic layer can include SU8, poly (methylmethacrylate) (PMMA), polyimide, parylene, benzocyclobutene (BCB) or others, and examples of the inorganic layer can include Al2O3, SiO2, SiNx or others. The organic layers can be connected to a high vacuum and a high pressure, and the inorganic layers can be connected to a high vacuum when the energy of the surface is adjusted using plasma or others, after flattening the surfaces by, for example, a process of chemical mechanical polishing.
[0300] [0300] The second layer of connection 269 couples the third battery of LED 243 to the second battery of LED 233. As illustrated in the drawing, the second layer of connection 269 can connect the second battery of LED 233 and the second color filter 247 um to the other. The second link layer 269 may be in contact with the second LED stack 233, but is not limited to this one. As illustrated in the drawing, the insulation layer can be arranged on the second LED stack 233, and the second connection layer 269 can also be in contact with the insulation layer 261. The second connection layer 269 can be formed by a layer transparent organic or a transparent inorganic layer.
[0301] [0301] Impact pads 251a, 251b, 251c and 251d can be arranged below insulation layer 229. Impact pads 251a, 251b, 251c and 251d include the first to third impact pads 251a, 251b and 251c and one common impact pad 251d.
[0302] [0302] The first impact pad 251a is electrically connected to the first conductivity type semiconductor layer 223a of the first LED stack 223. The first impact pad 251a can be connected to the first ohmic electrode 228a through opening 229a.
[0303] [0303] The second impact pad 251b is electrically connected to the first conductivity type semiconductor layer 233a of the second LED stack 233. The second impact pad 251b can be connected to the connection pad 228b through opening 229b.
[0304] [0304] The third impact pad 251c is electrically connected to the first semiconductor layer of conductivity type 243a of the third LED stack 243. The third impact pad 251c can be connected to connection pad 228c through opening 229c.
[0305] [0305] The common connection pad 251d is electrically connected to the second semiconductor layers of conductor type 223a, 233a and 243a of the first 223 LED battery, the second 233 LED battery and the third 243 LED battery. The common connection pad 251d can be connected to the first reflective electrode 226 through opening 229d.
[0306] [0306] Connectors 268b, 268c, 268d, 278c and 278d are arranged to electrically connect the second stack of LED 233 and the third stack of LED 243 to impact pads 251b, 251c and 251d.
[0307] [0307] The second connector 268b electrically connects the first conductivity type semiconductor layer 233a of the second LED stack 233 to the second impact pad 251b. The second connector 268b can be connected to the upper surface of the second ohmic electrode 238 and to the connection pad 228b. The second connector 268b and the second impact pad 251b can be arranged above and below the connection pad 228b while the connection pad 228b is interposed between them to be electrically connected to each other via the connection pad 228b. However, inventive concepts are not limited to these. For example, the connection pad 28 can be omitted and the second connector 268b can be connected directly to the second impact pad 251b. However, the second impact pad 251b and the second connector 268b can be formed by separate processes and can include different materials from each other.
[0308] [0308] The second connector 268b can penetrate through the first semiconductor layer of conductor type 233a of the second LED stack 233 and can be in contact with the first semiconductor layer of conductor type 233a. The second connector 268b is spaced from the second semiconductor layer of conductor type 233b and is isolated from the first stack of LED 223. For this purpose, the insulation layer 261 can cover a side wall of a through hole in which the second connector 268b is formed.
[0309] [0309] The third connector electrically connects the first conductivity type semiconductor layer 243a from the third LED stack 243 to the third impact pad 251c. The third connector can include a 3-1st connector 268c and a 3-2nd connector 278c.
[0310] [0310] The 3-1st connector 268c can penetrate through the first stack of LED 223 and the second stack of LED 233 and can be connected to connection pad 228c. The 3-1st connector 268c is isolated from the first LED battery 223 and the second LED battery 233, and for this purpose, the insulation layer 261 isolates the 3-1st connector 268c from the first and second LED batteries 223 and 233
[0311] [0311] According to an exemplary embodiment, the 3-1st connector 268c can include a pad region in the second 233 LED stack.
[0312] [0312] The 3-2nd connector 278c can penetrate through the first conductor-type semiconductor layer 243a of the third LED stack 243 to be connected to the third ohmic electrode 248 and the pad region of the 3-1st connector 268c. The 3-2nd connector 278c can be in contact with the upper surface of the third ohmic electrode 248 and with the first semiconductor layer of conductive type 243a.
[0313] [0313] Common connectors 268d and 278d electrically connect the second conductor-type semiconductor layer 233b from the second LED stack 233 and the second conductor-type semiconductor layer 243b from the third LED stack 243 to the common impact pad 251d.
[0314] [0314] The first common connector 268d can be connected to the second transparent electrode 245 and the first reflective electrode 226 and therefore is electrically connected to the common impact pad 251d. The first common connector 268d can penetrate through the second current spread layer 236. For example, when the second current spread layer 236 includes the hollow portion, the first common connector 268d can pass through the hollow portion of the second spread layer current 236. In the exemplary embodiment illustrated, the first common connector 268d is connected to the second transparent electrode 235 and is spaced from the second current spread layer 236, but is also electrically connected to the second current spread layer 236 through the second electrode transparent 235. In some exemplary embodiments, the first common connector 268d can be directly connected to the second current spread layer 236. For example, the upper surface of the second current spread layer 236 can be exposed through the second transparent electrode 235 and the first color filter 237, and the first common connector 268d can be r connected to the exposed upper surface of the second current spread layer 236.
[0315] [0315] The first common connector 268d can include a pad region to which the second common connector 278d can be connected. The pad region of the first common connector 268d can be provided on the first conductor-type semiconductor layer 233a of the second LED stack 233. However, since the first common connector 268d needs to be isolated from the first conductor-type semiconductor layer 233a, the insulation layer 261 can be interposed between the first common connector 268d and the first semiconductor layer of conductor type 233a.
[0316] [0316] The second common connector 278d can be connected to the third transparent electrode 245 and the first common connector 268d. The second common connector 278d can penetrate through the third LED stack 243 to be connected to the third transparent electrode 245 and therefore can be connected to the top surface of the third transparent electrode 245. The second common connector 278d is isolated from the first semiconductor layer of the conductor type 243a and, for that purpose, the insulation layer 271 can be interposed between the second common connector 278d and the first semiconductor layer of the conductor type 243a.
[0317] [0317] The second common connector 278d can penetrate through the third current spread layer 246. For example, when the third current spread layer 246 includes the hollow portion, the second common connector 278d may pass through the hollow portion of the third current spread layer 246. In the exemplary embodiment illustrated, the second common connector 278d is connected to the third transparent electrode 245 and is spaced from the third current spread layer 246, but it is also electrically connected to the third current spread layer 246 through of the third transparent electrode 245. In some exemplary embodiments, the second common connector 278d can be connected directly to the third current spreading layer 246. For example, the upper surface of the third current spreading layer 246 can be exposed through the third electrode transparent 245 and the second color filter 247, and the second common connector 2 78d can be connected directly to the exposed upper surface of the third current spread layer 246
[0318] [0318] According to exemplary modalities, the first LED battery 223 is electrically connected to the impact pads 251d and 251a, the second LED battery 233 is electrically connected to the impact pads 251d and 251b and the third LED battery 243 is electrically connected to the impact pads 251d and 251c. As such, the anodes of the first LED battery 223, the second LED battery 233 and the third LED battery 243 are electrically connected in common to the impact pad 251d and the cathodes of the first LED battery 223, the second LED battery 233 and the third LED stack 243 are electrically connected to the first, second and third impact pads 251a, 251b and 251c, respectively. In this way, the first, second and third LED batteries 223, 233 and 243 can be activated independently.
[0319] [0319] FIGS. 16A, 16B, 17A, 17B, 18A, 18B, 19A, 19B, 20A, 20B, 21A, 21B, 22A, 22B, 23A, 23B, 24A, 24B, 25A, 25B, 26A and 26B are schematic views and section views illustrating a method of manufacturing a light-emitting device 200 according to an exemplary embodiment. In the drawings, each plan view corresponds to a plan view of FIG. 14A, and each cross-sectional view is a cross-sectional view taken along the illustrated line of the corresponding plane view.
[0320] [0320] Referring to FIGS. 16A and 16B, the first LED stack 223 is grown on a first substrate 221. The first substrate 221 can be, for example, a GaAs substrate. The first LED stack 223 may be formed by semiconductor layers based on AlGaInP and includes the first semiconductor layer of conductivity type 223a, an active layer and the second semiconductor layer of conductivity type 223b. The first type of conductivity can be type n and the second type of conductivity can be type p.
[0321] [0321] Next, the second semiconductor layer of conductor type 223b is partially removed to expose the first semiconductor layer of conductor type 223a.
[0322] [0322] The insulation layer 225 is formed on the first LED stack 223, and the openings can be formed by standardizing the insulation layer 225. For example, SiO2 is formed on the first LED stack 223, a photoresistor is applied to SiO2 and a photoresistor pattern is then formed using photolithography and development. Then, SiO2 can be standardized using the photoresistor pattern as a recording mask to form openings.
[0323] [0323] Then, the ohmic contact layer 226a can be formed at each opening of the insulation layer 225. The ohmic contact layer 226a can be formed using lifting technology or the like. After the ohmic contact layer 226a is formed, the reflective layer 226b that covers the ohmic contact layer 226a and the insulation layer 225 is formed. The reflective layer 226b can be formed, for example, by Au, and can be formed using a lifting technique or the like. The first reflective electrode 226 is formed by the ohmic contact layer 226a and the reflective layer 226b.
[0324] [0324] The first reflective electrode 226 may have a shape in which three corner portions are removed from a rectangular region of the light-emitting device, as illustrated in the drawing. In addition, the ohmic contact layers 226a can be widely distributed in a lower portion of the first reflective electrode 226. Although FIG. 16A shows a region of the light emitting device, several regions of the light emitting device can be provided on the substrate 221 and the first reflecting electrode 226 is formed in each region of the light emitting device.
[0325] [0325] The first ohmic electrode 228a is formed in the first exposed semiconductor layer of conductor type 223a. The first ohmic electrode 228a is in ohmic contact with the first conductor-type semiconductor layer 223a and is isolated from the second conductor-type semiconductor layer 223b.
[0326] [0326] Connection pads 228b and 228c can be formed in insulation layer 225. Connection pads 228b and 228c can be formed together with reflective layer 226b, or be formed together with the first ohmic electrode 228a, but inventive concepts are not limited to these and can be formed by separate processes.
[0327] [0327] An insulation layer 229 is formed on the first reflective layer 226, on the first ohmic electrode 228a and on the connection pads 228c and 228d. The insulation layer 229 has openings 229a, 229b, 229c and 229d that expose the first ohmic electrode 228a, the connection pads 228c and 228d and the first reflective electrode 226, respectively. The insulation layer 229 can be formed, for example, by SiO2, Si3N4, SOG or others.
[0328] [0328] Referring to FIGS. 17A and 17B, the second LED stack 233 is grown on a second substrate 231 and the second transparent electrode 235 is formed on the second LED stack 233. The second LED stack 233 can be formed of semiconductor layers based on gallium nitride and may include the first conductive semiconductor layer 233a, an active layer and the second conductivity semiconductor layer 233b. The active layer can include a GaInN well layer. The first type of conductivity can be type n and the second type of conductivity can be type p.
[0329] [0329] The second substrate 231 is a substrate on which a semiconductor layer based on gallium nitride can be grown and can be different from the first substrate 221. A composition ratio of the GaInN well layer can be determined so that the second LED 233 battery can emit green light, for example. The second transparent electrode 235 is in ohmic contact with the second semiconductor layer of conductivity type 233b.
[0330] [0330] The second transparent electrode 235 and the second conductive semiconductor layer 233b are partially removed to expose the first conductive semiconductor layer 233a. The exposed region of the first conductive-type semiconductor layer 233a can be selected to not overlap the exposed region of the first conductive-type semiconductor layer 223a.
[0331] [0331] The first color filter 237 is formed on the second transparent electrode 235. The first color filter 237 can cover the first exposed conductive type semiconductor layer 233a. Since the material forming the first color filter 237 is substantially the same as that described with reference to FIGS. 15A and 15B, detailed descriptions will be omitted to avoid redundancy.
[0332] [0332] The first color filter 237 is standardized to form openings exposing the second transparent electrode 235 and an opening exposing the first conductive-type semiconductor layer 233a.
[0333] [0333] Next, the second current spread layer 236 is formed in the first color filter 237. The second current spread layer 236 is formed by a metal layer. The second current spreading layer 236 may include the pad region 236a and the extension 236b. The pad region 236a can be formed to have substantially a ring shape and to have a hollow region exposing the first color filter 237 in the center thereof. Extension 236b can extend from the pad region 236a and can be connected to the second transparent electrode 235 exposed through the opening of the first color filter 237. Extension 236b can extend substantially in a diagonal direction, but is not limited to this. Extension 236b can take several forms. Although FIG. 17A shows a region of the light emitting device, several regions of the light emitting device can be provided on the substrate 231 and the second current spread layer 236 can be formed in each region of the light emitting device.
[0334] [0334] The second ohmic electrode 238 is formed in the first semiconductor layer of conductor type 233a. The second ohmic electrode 238 is in ohmic contact with the first semiconductor layer of conductor type 233a and can be formed, for example, by Ti / Al. A side surface of the second ohmic electrode 238 may be in contact with the first color filter 237 and therefore it is possible to prevent light from leaking into a region between the second ohmic electrode 238 and the first color filter 237. The second electrode ohmic 238 and the second current spreading layer 236 can also be formed with each other by the same process, or they can be formed to include materials different from one another through a separate process.
[0335] [0335] Referring to FIGS. 18A and 18B, the third LED stack 243 is grown on a third substrate 241 and the third transparent electrode 245 is formed on the third LED stack 243. The third LED stack 243 can be formed of semiconductor layers based on gallium nitride and it may include the first conductivity type semiconductor layer 243a, an active layer and the second conductivity type semiconductor layer 243b. The active layer can also include a GaInN well layer. The first type of conductivity can be type n and the second type of conductivity can be type p.
[0336] [0336] The third substrate 241 is a substrate on which a semiconductor layer based on gallium nitride can be grown and can be different from the first substrate 221. A proportion of GaInN composition can be determined so that the third LED stack 243 can emit blue light, for example. The third transparent electrode 245 is in ohmic contact with the second semiconductor layer of conductivity type 243b.
[0337] [0337] The third transparent electrode 245 and the second conductive semiconductor layer 243b are partially removed to expose the first conductive semiconductor layer 243a. The exposed region of the first semiconductor layer of conductor type 243a can be selected so as not to overlap the exposed regions of the first semiconductor layers of conductor type 223a and 233a.
[0338] [0338] The second color filter 247 is formed on the third transparent electrode 245. The second color filter 247 can also cover the first exposed conductive semiconductor layer 243a. Since the material forming the second color filter 247 is substantially the same as that described with reference to FIGS. 15A and 15B, detailed descriptions will be omitted to avoid redundancy.
[0339] [0339] The second color filter 247 can be standardized to form openings exposing the third transparent electrode 245 and an opening exposing the first conductive type semiconductor layer 243a.
[0340] [0340] Then, the third layer of spreading current 246 is formed in the second color filter 247. The third layer of spreading current 246 is formed by a layer of metal. The third current spreading layer 246 may include pad region 246a and extension 246b. The pad region 246a can be formed to have substantially a ring shape and to have a hollow region exposing the second color filter 247 in the center thereof. A process of standardizing the third current spread layer 246 can be omitted in a subsequent process, forming the hollow portion in the third current spread layer 245 in advance, to simplify the manufacturing process of the light emitting device 200. However , the inventive concepts are not limited to these, and the pad region 246a can be formed without the hollow portion, and the hollow portion can be formed by modeling the pad region 246a in a later process.
[0341] [0341] Extension 246b can extend from pad region 246a and can be connected to the exposed third transparent electrode 245 through the opening of the second color filter 247. Extension 246b can extend substantially along an edge, as illustrated in drawing, but is not limited to this. The 246b extension can take several forms. Although FIG. 18A shows a region of the light emitting device, several regions of the light emitting device can be provided on the substrate 241 and the third current spread layer 246 is formed in each region of the light emitting device.
[0342] [0342] The third ohmic electrode 248 is formed in the first semiconductor layer of conductor type 243a. The third ohmic electrode 248 is in ohmic contact with the first semiconductor layer of conductor type 243a and can be formed, for example, by Ti / Al. A side surface of the third ohmic electrode 248 may be in contact with the second color filter 247 and therefore it is possible to prevent light from leaking into a region between the third ohmic electrode 248 and the second color filter
[0343] [0343] Referring to FIGS. 19A and 19B, the impact pads 251a, 251b, 251c and 251d are formed on the first LED stack 223 of FIGS. 16A and 16B. Impact pads 251a, 251b, 251c and 251d are formed in insulation layer 229. Impact pads 251a, 251b, 251c and 251d may include, for example, a weld barrier layer, a body and a surface layer . The solder barrier layer can be formed, for example, by a single layer or a multilayer, including at least one of Ti, Ni, Ta, Pt, Pd, Cr and the like, the body can be formed of Cu and the surface layer can be formed of Au or Ag. The surface layer can improve the wettability of a weld and assist in the assembly of the impact pads 251a, 251b, 251c and 251d, and the weld barrier layer can prevent the diffusion of metallic material , such as Sn, in the weld to improve the reliability of the light emitting device 200.
[0344] [0344] The first impact pad 251a is connected to the first ohmic electrode 228a through opening 229a, the second impact pad 251b is connected to connection pad 228b through opening 229b, the third impact pad 251c is connected to the connection 228c through opening 229c, and the common impact pad 251d is connected to the first reflective electrode 226 through opening 229d.
[0345] [0345] Filler material 253 can fill regions between impact pads 251a, 251b, 251c and 251d. Impact pads 251a, 251b, 251c and 251d are formed for each of the light-emitting devices on substrate 221, and filler material 253 fills the regions between these impact pads 251a, 251b, 251c and 251d.
[0346] [0346] Referring to FIGS. 20A and 20B, substrate 221 is then removed from the first LED stack 223. FIG. 20B illustrates an inverted view of FIG. 19B. Impact pads 251a, 251b, 251c and 251d and filler 253 can function as a support structure, and substrate 221 can be removed from the first LED stack 223 by chemical etching or the like. Therefore, the first conductivity-like semiconductor layer 223a is exposed. In order to improve the efficiency of light extraction, a surface of the first semiconductor layer 223a of the exposed conductivity type can be textured.
[0347] [0347] Referring to FIGS. 21A and 21B, the second LED stack 233 of FIGS. 17A and 17B are connected to the first LED stack 223. Layers of bonding material are formed in the first LED stack 223 and the first color filter 237, respectively, and are bonded together to form the first bonding layer 239.
[0348] [0348] The second current spreading layer 236 and the impact pads 251b and 251d are connected to each other to be aligned with each other. In particular, a central portion of the pad region 236a of the second current spreading layer 236 can be aligned to be positioned on the first reflective electrode 226 and the second ohmic electrode 238 can be aligned to be positioned on the connection pad 228b.
[0349] [0349] Next, the second substrate 231 is removed from the second LED stack 233 using technology such as laser lifting technology, chemical lifting technology or the like. Therefore, the first conductivity-type semiconductor layer 233a of the second LED stack 233 is exposed from the above. In some exemplary embodiments, a surface of the first semiconductor layer 233a of the exposed conductivity type is textured to form a rough surface.
[0350] [0350] Referring to FIGS. 22A and 22B, the holes h1, h2 and h3 that penetrate through the second LED stack 233 and the first LED stack 223 are then formed. The orifice h1 and the orifice h2 can penetrate sequentially through the second LED battery 233, the second transparent electrode 235, the first color filter 237, the first connection layer 239, the first LED battery 223 and the insulation layer 225 When the hollow portion is not formed in the second current spreading layer 236, the second current spreading layer 236 is patterned when orifice h1 is formed, thus forming the hollow portion. Meanwhile, hole h1 can partially expose the upper surface of the second transparent electrode 235 and exposes the upper surface of the first reflective electrode 226. Although FIGS. 22A and 22B show that the upper surface of the second transparent electrode 235 is exposed through hole h1, the upper surface of the second current spreading layer 236 can also be exposed. Hole h2 exposes the upper surface of connection pad 228c.
[0351] [0351] Hole h3 can penetrate through the first semiconductor layer of conductor type 233a to expose the upper surface of the second ohmic electrode 238 and can penetrate through the first connection layer 239, the first LED stack 223 and the insulation layer 225 to expose the pad connection 228b.
[0352] [0352] Referring to FIGS. 23A and 23B, the insulating layer 261 can be formed to cover the side walls of the holes h1, h2 and h3. The insulation layer 261 can also cover the top surface of the second LED stack 233.
[0353] [0353] Next, connectors 268b, 268c and 268d are formed. Connector 268b connects the second exposed ohmic electrode 238 to connection pad 228b. The connector 268b connects the second ohmic electrode 238 and the connection pad 228b. In addition, connector 268b can be connected to the first semiconductor layer of conductor type 233a. The connector 268b is electrically isolated from the first LED stack 223 by the insulation layer 261.
[0354] [0354] Connector 268c is connected to connection pad 228c exposed through hole h2. The connector 268c is electrically isolated from the second LED battery 233 and the first LED battery 223 by the insulation layer 261. The connector 268c can have a pad region on the second LED battery 233.
[0355] [0355] Connector 268d is connected to the second transparent electrode 235 exposed through hole h3 and the first reflective electrode 226 and electrically connects the second transparent electrode 235 and the first reflective electrode 226 to each other. The connector 268d is isolated from the first conductor-type semiconductor layer 233a of the second LED stack 233 and the first conductor-type semiconductor layer 223a from the first LED stack 223. In another exemplary embodiment, connector 268d can be connected to the second layer of current spreading
[0356] [0356] Referring to FIGS. 24A and 24B, the third LED stack 243 of FIGS. 18A and 18B is connected to the second LED stack 233.
[0357] [0357] A layer of bonding material can be formed on the second LED stack 233 in which connectors 268b, 268c and 268d are formed and another layer of bonding material can be formed on the second color filter 247. The second layer of bonding 269 can be formed by bonding between layers of bonding material. In addition, the third substrate 241 can be removed from the third LED stack 243 using a technology, such as laser lifting technology, chemical lifting technology or others. Therefore, the first semiconductor layer of the conductive type 243a can be exposed and a rough surface by texturing the surface can be formed on a surface of the first semiconductor layer of the exposed conductive type 243a.
[0358] [0358] The second connection layer 269 can also be in contact with the upper surface of the second LED stack 233, but it can also be in contact with the insulation layer 261, as illustrated in the drawing.
[0359] [0359] Referring to FIGS. 25A and 25B, the holes that penetrate through the third LED stack 243 are formed to expose connectors 268c and 268d. The holes penetrate through the second connection layer 269. The upper surface of the third ohmic electrode 248 is exposed through the hole that exposes the connector 268c and the upper surface of the third transparent electrode 245 is partially exposed by the hole that exposes the connector 268d. Although the upper surface of the third transparent electrode 245 is described as being exposed by the hole that exposes the connector 268d, in some exemplary embodiments, the third transparent electrode 245 and the second color filter 247 can be removed and the upper surface of the third current a spreading layer 246 can also be exposed.
[0360] [0360] Referring to FIGS. 26A and 26B, the insulating layer 271 can be formed to cover the side walls of the holes. The insulation layer 271 can also cover the top surface of the third LED stack 243.
[0361] [0361] Then, connectors 278c and 278d are formed. Connector 2278c connects the exposed third ohmic electrode 248 to connector 268c. The connector 2278c connects the third ohmic electrode 248 and the connector 268c to each other. In addition, connector 2278c can be connected to the first conductor-type semiconductor layer 243a.
[0362] [0362] Connector 278d can be connected to the third transparent electrode 245 and connector 268d. Therefore, the second conductor-type semiconductor layer 243b of the third LED stack 243 is electrically connected to the common impact pad 251d. The connector 278d is electrically isolated from the first semiconductor layer of conductor type 243a by the insulation layer 271. The connector 278d can pass through the hollow portion of the third current spreading layer 246. In another exemplary embodiment, the upper surface of the third layer of current spread 246 can be exposed and connector 278d can be connected to the top surface of the third current spread layer 246.
[0363] [0363] Then, the light emitting device 200 is completed by dividing the substrate into regions of the light emitting device. As illustrated in FIG. 26A, impact pads 251a, 251b, 251c and 251d can be arranged at four corners of each light emitting device 200. In addition, impact pads 251a, 251b,
[0364] [0364] According to exemplary modalities, a light-emitting device includes the first, second and third LED batteries 223, 233 and 243, in which their anodes are electrically connected in common, and their cathodes are connected independently. However, the inventive concepts are not limited to them, and the anodes of the first, second and third LED batteries 223, 233 and 243 can be connected independently to the impact pads, and their cathodes can be electrically connected in common .
[0365] [0365] The light emitting device 200 can include the first, second and third LED batteries 223, 233 and 243 to emit red, green and blue light and therefore can be used as a single pixel on a display device. As described with reference to FIG. 14, a display device can be provided by arranging a plurality of light emitting devices 200 on circuit board 201. Since the light emitting device 200 includes the first, second and third LED cells 223, 233 and 243, a subpixel area in a pixel can be increased. In addition, the first, second and third LED batteries 223, 233 and 243 can be assembled by mounting a light emitting device 200, thereby reducing the number of assembly processes.
[0366] [0366] Meanwhile, as described with reference to FIG. 14, the light-emitting devices 200 mounted on the circuit board 201 can be driven by a passive matrix method or an active matrix method.
[0367] [0367] FIGS. 27A and 27B are schematic plan views and cross-sectional views of a light emitting device 2000 according to another exemplary embodiment.
[0368] [0368] Referring to FIGS. 27A and 27B, the light emitting device 2000 according to an exemplary embodiment can include the impact pads 251a, 251b, 251c and 251d, the filling material 253, the first LED stack 223, the second LED stack 233, the third LED stack 243, insulation layers 225, 229, 2161 and 2171, the first reflective electrode 226, the second transparent electrode 235, the third transparent electrode 245, the first ohmic electrode 228a, the connection pads 228b and 228c, the second current spread layer 236, the third current spread layer 246, the first color filter 237, the second color filter 247, a first link layer 2139, a second link layer 2169 and connectors 2168b, 2168c , 2168d, 2178c and 2178d.
[0369] [0369] The light emitting device 2000, according to the exemplary embodiment illustrated, is substantially similar to the light emitting device 200 described above, except that the second ohmic electrode 238 and the third ohmic electrode 248 are omitted. As such, detailed descriptions of the same items or items similar to those of the light emitting device 200 will be omitted to avoid redundancy.
[0370] [0370] The second LED stack 233 includes the first conductivity semiconductor layer 233a, an active layer, and the second conductivity semiconductor layer 233b. The second semiconductor layer of conductor type 233b can substantially cover the entire bottom surface of the first semiconductor layer of conductor type 233a and therefore the bottom surface of the first semiconductor layer of conductor type 233a cannot be exposed. The third LED stack 243 includes the first conductivity-type semiconductor layer 243a, an active layer, and the second conductivity-type semiconductor layer 243b. The second semiconductor layer of the conductor type 243b can substantially cover the entire bottom surface of the first semiconductor layer of the conductor type 243a and therefore the bottom surface of the first semiconductor layer of the conductor type 243a cannot be exposed. As such, the second ohmic electrode 238 and the third ohmic electrode 248 of the light emitting device 200 are omitted in the light emitting device 2000.
[0371] [0371] The first color filter 237 can be standardized in advance, and the through hole for connecting the connectors to each other can be easily formed later. However, the inventive concepts are not limited to these, and the through hole can penetrate through the first color filter 237.
[0372] [0372] The connector 2168b can penetrate through the first and second semiconductor layers of conductor type 233a and 233b of the second LED stack 233 and the second transparent electrode 235 to be connected to the connection pad 228b. The connector 2168b can be connected to the top surface of the first semiconductor layer of conductor type 233a.
[0373] [0373] The connector 2168c is substantially similar to the connector 268c of FIG. 15B, but the first color filter 237 can be standardized in advance and, therefore, is not exposed to an internal wall of the hole where the connector 2168c is formed. However, the inventive concepts are not limited to these, and the connector 2168c can be exposed to the inner wall of the hole.
[0374] [0374] The connector 2168d is connected to the second current spreading layer 236 and is connected to the first reflective electrode 226. The connector 2168d can be spaced from the second transparent electrode 235 and can be electrically connected to the second transparent electrode 235 through the second layer current spreader 236. The connector 2168d can include a pad region on the second LED stack 233. The pad region can be arranged in the hole by penetrating through the second LED stack 233.
[0375] [0375] Insulation layer 2161 isolates connector 2168b from the second conductive semiconductor layer 233b of the second LED stack 233 and the second transparent electrode 235. Insulation layer 2161 electrically insulates connector 2168c from the first and second LED cells 223 and 233 and also isolates connector 2168d from the first conductive semiconductor layer 223a from the first LED stack 223.
[0376] [0376] The first connection layer 2139 can connect the first stack of LED 223 and the first color filter 237 to each other and can also be in contact with a portion of the second transparent electrode 235. In addition, the second connection layer 2169 may be in contact with the second color filter 247 and the third transparent electrode 245.
[0377] [0377] Connector 2178c is connected to the first conductor-type semiconductor layer 243a of the third LED stack 243 and is also connected to connector 2168c. The connector 2178c can be connected to the top surface of the first semiconductor layer of conductor type 243a. The connector 2178c is isolated from the second semiconductor layer of conductor type 243b and the third transparent electrode 245 by the insulation layer
[0378] [0378] Connector 2178d connects the third current spread layer 246 and connector 168 to each other. A top surface of the 2178d connector can be positioned on the third stack of LED 243. However, the position of the top surface of the 2178d connector is not necessarily limited to this, and the top surface of the 2178d connector can be positioned in the hole formed in the third stack 243 LED.
[0379] [0379] The insulation layer 2171 can cover a side wall of the hole formed in the third LED stack 243 and isolates the connector 2178c from the second semiconductor layer of conductor type 243b and the third transparent electrode 245. In addition, the insulation layer 2171 it can isolate the connector 2178d from the first semiconductor layer of conductor type 243a.
[0380] [0380] FIGS. 28A, 28B, 29A, 29B, 30A, 30B, 31A, 31B, 32A, 32B, 33A, 33B, 34A and 34B are plan views and cross-sectional views illustrating a method of manufacturing a 2000 light emitting device in accordance with with an exemplary modality.
[0381] [0381] Referring to FIGS. 28A and 28B, the second LED stack 233 is grown on the second substrate 231 and the second transparent electrode 235 is formed on the second LED stack 233. According to the exemplary embodiment illustrated, the process of partial removal of the second transparent electrode 235 and of the second semiconductor layer of conductor type 233b described with reference to FIGS. 17A and 17B is omitted.
[0382] [0382] The first color filter 237 is formed on the second transparent electrode 235. Since the material forming the first color filter 237 is substantially the same as that described with reference to FIGS. 15A and 15B, detailed descriptions will be omitted to avoid redundancy. Then, the first color filter 237 is standardized to expose the second transparent electrode 235. The regions that expose the second transparent electrode 235 can include regions to which the extension 236b must be connected and can also include regions to which the through holes must be connected. be formed.
[0383] [0383] Then, the second current spread layer 236 is formed in the first color filter 237. Since the second current spread layer 236 is substantially the same as that described with reference to FIGS. 17A and 17B, detailed descriptions will be omitted.
[0384] [0384] Referring to FIGS. 29A and 29B, the third LED stack 243 is grown on the third substrate 241 and the third transparent electrode 245 is formed on the third LED stack 243. According to the exemplary embodiment illustrated, the partial removal process of the third transparent electrode 245 and of the second semiconductor layer of conductor type 243b described with reference to FIGS. 18A and 18B is omitted.
[0385] [0385] The second color filter 247 is formed on the third transparent electrode 245. Since the material forming the second color filter 247 is substantially the same as that described with reference to FIGS. 15A and 15B, detailed descriptions will be omitted to avoid redundancy.
[0386] [0386] The second color filter 247 is standardized to expose the third transparent electrode 245. The regions that expose the third transparent electrode 245 can include regions to which the extension 246b should be connected and can also include regions to which the through holes must be trained.
[0387] [0387] Then, the third current spreading layer 246 is formed on the second color filter 247. Since the third current spreading layer 246 is substantially the same as that described with reference to FIGS. 18A and 18B, detailed descriptions will be omitted.
[0388] [0388] Referring to FIGS. 30A and 30B, the impact pads 251a, 251b, 251c and 251d are formed on the first LED stack 223 and the substrate 221 is removed to expose the top surface of the first LED stack 223. The rough surface by surface texturing can be formed on the exposed upper surface of the first 223 LED stack.
[0389] [0389] Then, the second LED stack 233 of FIGS. 28A and 28B are connected to the first LED stack 223 using the first link layer 2139 and the substrate 231 is removed.
[0390] [0390] Referring to FIGS. 31A and 31B, holes h1, h2 and h3 that penetrate through the second LED stack 233 and the first LED stack 223 are formed. The orifices h1, h2 and h3 also penetrate through the first bonding layer 2139.
[0391] [0391] Hole h1 exposes the second layer of current spreading 236 and also exposes the first reflective layer 226.
[0392] [0392] Hole h2 exposes connection pad 228c. In addition, the second LED battery 233, the second transparent electrode 235, the first LED battery 223 and the insulation layer 225 can be exposed to a side wall of the orifice h2. The first color filter 237 can be spaced from the orifice h2, but the inventive concepts are not limited to this, and the first color filter 237 can be exposed on the side wall of the orifice h2.
[0393] [0393] Hole h3 exposes connection pad 228b. In addition, the second LED stack 233, the second transparent electrode 235, the first LED stack 223 and the insulation layer 225 can be exposed to a side wall of the hole. The first color filter 237 can be spaced from hole h3, but the inventive concepts are not limited to this, and the first color filter 237 can be exposed on the side wall of hole h3.
[0394] [0394] Referring to FIGS. 32A and 32B, the insulating layer 2161 covering the side walls of the holes h1, h2 and h3 is then formed. The insulation layer 2161 can also cover the top surface of the second 233 LED stack.
[0395] [0395] The insulation layer 2161 exposes the first reflective electrode 226 and the connection pads 228b and 228c and also exposes the second layer of current spreading 236.
[0396] [0396] Connectors 2168d, 2168c and 2168b are formed in holes h1, h2 and h3. The connector 2168b is connected to the first conductor-type semiconductor layer 233a and is connected to the connection pad 228b. The connector 2168c is isolated from the second stack of LED 233 and is connected to the connection pad 228c. The connector 2168d is connected to the second layer of current spreading 236 and is connected to the first reflective electrode
[0397] [0397] Then, with reference to FIGS. 33A and 33B, the third LED stack 243 of FIGS. 29A and 29B are connected to the second LED stack 233 and the substrate 241 is removed. The third LED battery 243 can be connected to the second LED battery 233 through the second connection layer 2169.
[0398] [0398] Referring to FIGS. 34A and 34B, holes are formed that penetrate through the third LED stack 243 to expose the connectors 2168c and 2168d, the insulation layer 2171 covering the side walls of the holes and the connectors 2178c and 2178d are formed.
[0399] [0399] Connector 2178c can be connected to the top surface of the second semiconductor layer of conductor type 243a and can also be connected to a pad region of connector 2168c. The pad region of the 2168c connector can be wider than a hole width that penetrates through the third LED stack
[0400] [0400] Then, the light emitting device 2000 is completed by dividing the substrate into regions of the light emitting device. As illustrated in FIG. 34A, the impact pads 251a, 251b, 251c and 251d can be arranged in four corners of each light emitting device 2000. In addition, the impact pads 251a, 251b, 251c and 251d can be substantially rectangular in shape, but not are necessarily limited to these. In some exemplary embodiments, an insulating layer covering a side surface of each light emitting device may be additionally formed and the insulating layer may include the reflective layer that reflects the light or the absorbent layer that absorbs the light, as described above . Therefore, light directed to the side surface of the first, second and third LED cells 223, 233 and 243 can be reflected or absorbed to block light interference between pixels, and the light efficiency of the light emitting device can be improved or the contrast ratio of the display device can be improved.
[0401] [0401] Meanwhile, the processes for forming the through holes and forming the connectors are described as being performed whenever the second LED stack 233 and the third LED stack 243 are connected to each other. However, the processes for connecting the connectors can also be performed after the second LED 233 battery and the third 243 LED battery are connected. In addition, the connector is described as formed using the through hole, but the inventive concepts are not limited to this. For example, the side surface of the light emitting device can be engraved and the connector can be formed along the side surface of the light emitting device.
[0402] [0402] FIGS. 35A and 35B are a plan view and a cross-sectional view illustrating a stack structure of light emitting diodes according to another exemplary embodiment. A light emitting diode cell structure, according to an exemplary embodiment, includes the second LED battery 233 and the third LED battery 243 which are connected, which can be used to form a light emitting device 2001 shown in FIGS . 36A and 36B.
[0403] [0403] Referring to FIGS. 35A and 35B, the structure of the light emitting diode stack may include impact pads 251a, 251b, 251c and 251d, filler material 253, the first LED stack 223, the second LED stack 233, the second stack LED 233, the third LED stack 243, the insulation layers 225 and 229, the first reflective electrode 226, the second transparent electrode 235, the third transparent electrode 245, the first ohmic electrode 228a, the second ohmic electrode 238, the connection pads 228b and 228c, a second current spreading layer 2136, a third current spreading layer 2146, the first color filter 237, the second color filter 247, the first connection layer 239 and the second layer of connection 269. Although FIG. 35A shows only one region of the light emitting device, a plurality of regions of the light emitting device can be connected continuously to each other.
[0404] [0404] The structure of the impact pads 251a, 251b, 251c and 251d and the filling material 253 for the second LED stack 233 is substantially the same as the structure of FIGS. 21A and 21B, and therefore detailed descriptions will be omitted.
[0405] [0405] However, while the second current spread layer 236 of FIGS. 21A and 21B have the hollow portion in the pad region 236a, the second current spreading layer 2136, according to the exemplary embodiment illustrated, can avoid the need for the hollow portion.
[0406] [0406] In addition, the second ohmic electrode 238 is illustrated as being formed in some regions of the first semiconductor layer of conductor type 233a, but in some exemplary embodiments, the connection can also be performed when the second ohmic electrode 238 is omitted, as described with reference to FIGS. 30A and 30B.
[0407] [0407] Meanwhile, going back to FIGS. 21A to 22B, the second LED stack 233 is connected to the first LED stack 223 and the through holes h1, h2 and h3 are then formed. However, the through-hole formation process is omitted in the exemplary embodiment illustrated, and the third LED stack 243 is connected to the second LED stack 233 using the second link layer 269.
[0408] [0408] The third LED stack 243, the second color filter and the third current scattering layer 2146, according to the exemplary embodiment illustrated, can be manufactured by the method described with reference to FIGS. 29A and 29B, and after the third LED stack 243 is turned on, substrate 241 is removed. However, the third current spreading layer 2146 may not require the hollow portion, unlike the third current spreading layer 246 shown in FIG. 24A.
[0409] [0409] Furthermore, the third LED battery 243 is illustrated as being connected to the second LED battery 233 when the third ohmic electrode 248 is omitted in the first conductive semiconductor layer 243a, but the inventive concepts are not limited to this one. For example, as described with reference to FIGS. 18A and 18B, a portion of the first conductive type semiconductor layer 243a can be exposed, the third ohmic electrode 248 can be formed on the exposed first conductive type semiconductor layer 243a and the third LED stack 243 can be connected to the second LED stack 233 when the third ohmic electrode 248 is formed.
[0410] [0410] Therefore, the structure of the light emitting diode stack, as shown in FIG. 35B can be provided to form the 2001 light emitting device.
[0411] [0411] FIG. 36A is a plan view of the light emitting device 2001 and FIGS. 36B and 36C are schematic cross-sectional views along lines G-H and I-J of FIG. 36A, respectively.
[0412] [0412] Referring to FIGS. 36A, 36B and 36C, since a stack structure of the light emitting device 2001 is substantially the same as that described with reference to FIGS. 35A and 35B, their detailed descriptions are omitted and below, an insulation layer 2261 and connectors 2278b, 2278c and 2278d with a shape altered by default will be described.
[0413] [0413] The third LED stack 243, the third transparent electrode 245 and the second color filter 247 are partially removed to expose the third current spread layer 2146, and the second LED stack 233, the second transparent electrode 245 and the first color filter 237 is removed to expose the second ohmic electrode 238 and the second current spreading layer 2136.
[0414] [0414] In addition, the first connection layer 239, the first LED stack 223 and the insulation layer 225 are partially removed to expose connection pads 228b and 228c and the first reflective electrode 226.
[0415] [0415] In addition, the pattern can also be performed for a dicing region to separate the light-emitting devices, exposing an upper surface of the insulation layer 229 or the filling material 253.
[0416] [0416] Insulation layer 2261 covers the side surfaces of the first, second and third LED batteries 223, 233 and 243 and other layers. Insulation layer 2261 has openings that expose the third current spreading layer 2146, the second ohmic electrode 238, the second current spreading layer 2136, the first reflective electrode 226 and the connecting pads 228b and 228c. The insulation layer 2261 can be formed by a single layer or several layers of a light transmitting material, such as SiO2, Si3N4 or others. The insulation layer 2261 can also cover substantially the entire upper surface of the third LED stack 243. In addition, the insulation layer 2261 can include a distributed Bragg reflector that reflects the light emitted from the first LED stack 223, the second battery of LED 233 and the third stack of LED 243, thus preventing the emission of light to the side surface of the light emitting device 2001. Alternatively, insulation layer 2261 may include a transparent insulation film and a reflective metal layer, or an organic reflective layer of a multilayer structure formed thereon to reflect light, or it may include a light absorbing layer, such as a black epoxy to block light. The 2261 insulation layer may include the reflective layer or the absorbent layer, making it possible to prevent light interference between pixels and to improve the contrast ratio of the display device. When the insulation layer 2261 includes the reflective layer or the absorbent layer, the insulation layer 2261 has an opening that exposes the top surface of the third LED stack 243.
[0417] [0417] Connectors 2278b, 2278c and 2278d are arranged in insulation layer 2261 along the side surface of the light emitting device 2001. As illustrated in FIG. 36B, connector 2278c connects the first conductor-type semiconductor layer 243a of the third LED stack 243 to the connection pad 228c. Therefore, the first conductor-type semiconductor layer 243a of the third LED stack 243 is electrically connected to the third impact pad 251c. The 2278c connector can directly connect the third LED stack 243a to the connection pad 228c. In this case, connector 2278c may include an extension on the second LED stack 233 for current distribution. In some exemplary embodiments, when the third ohmic electrode 248 is formed, the connector 2278c can be connected to the third ohmic electrode 248. In this case, the third ohmic electrode 248 can include an extension along with a pad region.
[0418] [0418] Referring to FIG. 36C, connector 2278b connects the second ohmic electrode 238 to the connection pad 228b. Therefore, the first conductor-type semiconductor layer 233a of the second LED stack 233 is electrically connected to the second impact pad 251b. When the second ohmic electrode 238 is omitted in some exemplary embodiments, connector 2278b can be connected to the first conductive-type semiconductor layer 233a. The connector 2278c is connected to the third current spreading layer 2146, the second current spreading layer 2136 and the first reflective electrode 226. Therefore, the second conductivity semiconductor layer 243b of the third LED stack 243, the second layer of conductivity semiconductors 233a from the second LED stack 233 and the second conductivity semiconductor layer 223b from the third LED stack 223 are electrically connected in common to the common impact pad 251d.
[0419] [0419] In the exemplary example illustrated, a connector 278d is described as connecting the third current spreading layer 2146, the second current spreading layer 2136 and the first reflective electrode 226 to each other, however, the inventive concepts are not limited to these and a plurality of connectors can be used. For example, the third current spreading layer 2146 and the second current spreading layer 2136 can be connected together by a connector, and the second current spreading layer 2136 and the first reflective electrode 226 can also be connected to each other. another through another connector.
[0420] [0420] The light emitting device 2001 can be manufactured by standardizing the structure of the light emitting diode stack described with reference to FIGS. 35A and 35B and dividing it into a separate unit.
[0421] [0421] More particularly, the third LED battery 243, the third transparent electrode 245 and the second color filter 247 are standardized and are partially removed. The third LED stack 243, the third transparent electrode 245 and the second color filter 247 are removed to expose the third current spread layer 2146, as illustrated in FIG. 36C. The third LED stack 243, the third transparent electrode 245 and the second color filter 247 are removed from the dicing region to separate the light-emitting devices and a periphery of the upper regions of the connection pads 228b and 228c separately and one a portion of an upper region of the first reflector electrode 226 is also removed. Meanwhile, when the third ohmic electrode 248 is formed on the third LED stack 243, the third ohmic electrode 248 is also exposed.
[0422] [0422] Then, the second bond layer 269 and the second LED stack 233 are standardized to expose the second ohmic electrode 238. In addition, the second transparent electrode 235 and the first color filter 237 are removed to expose the second layer current spreader 2136. The second link layer 269, the second LED stack 233, the second transparent electrode 235 and the first color filter 237 are removed from the dicing region to separate the light-emitting devices separately.
[0423] [0423] So, the first connection layer 239, the first LED stack 223 and the insulation layer 225 are standardized to expose connection pads 228b and 228c and the first reflective electrode 226. The first connection layer 239, the first stack of LED 223 and insulation layer 225 are removed from the dicing region to separate the light-emitting devices separately.
[0424] [0424] Then, the 2261 insulation layer that covers the exposed side surfaces of the light-emitting devices is formed. The insulation layer 2261 is patterned using photolithography and recording processes or the like, and therefore the openings that expose the second and third current expansion layers 236 and 246, the second ohmic electrode 238, the connection pads 228b and 228c and the first reflector the electrode 226 are formed.
[0425] [0425] Next, connectors 2278b, 2278c and 2278d are formed to electrically connect the second and third current spreading layers 236 and 246, the second ohmic electrode 238, the connection pads 228b and 228c and the first reflective electrode 226 , which are exposed.
[0426] [0426] FIG. 37 is a schematic plan view of a display device according to an exemplary embodiment.
[0427] [0427] Referring to FIG. 37, the display device, according to an exemplary embodiment, includes a circuit board 301 and a plurality of light-emitting devices
[0428] [0428] Circuit board 301 may include a circuit for passively driving the matrix or active driving the matrix. In an exemplary embodiment, circuit board 301 can include interconnect lines and resistors. In another exemplary embodiment, circuit board 301 can include interconnect lines, transistors and capacitors. Circuit board 301 may also have electrode pads arranged on an upper surface of the circuit board to allow electrical connection to the circuit on it.
[0429] [0429] The light-emitting devices 300 are arranged on the circuit board 301. Each of the light-emitting devices 300 can constitute a pixel. The light emitting device 300 includes electrode pads 373a, 373b, 373c, 373d, which are electrically connected to the circuit board 301. In addition, the light emitting device 300 may include a substrate 341 on an upper surface thereof. Since the light emitting devices 300 are separated from each other, the substrates 341 disposed on the upper surfaces of the light emitting devices 300 are also separated from each other.
[0430] [0430] Details of the light emitting device 300 will be described with reference to FIG. 38A and FIG. 38B. FIG. 38A is a schematic plan view of a light emitting device 300 for a display, according to an exemplary embodiment, and FIG. 38B is a schematic cross-sectional view along a line A-A of FIG. 38A. Although the electrode pads 373a, 373b, 373c, 373d are illustrated and described as being arranged on the upper side of the light emitting device 300, the light emitting device 300 can be connected to the circuit board 301 of FIG. 37, and electrodes 373a, 373b, 373c, 373d can be arranged on the underside.
[0431] [0431] Referring to FIG. 38A and FIG. 38B, the light-emitting device 300 may include a first substrate 321, a second substrate 341, a distributed Bragg reflector 322, a first stack of LED 323, a second stack of LED 333, a third stack of LED 343, a third stack LED 343, a first transparent electrode 325, a second transparent electrode 335, a third transparent electrode 345, an ohmic electrode 346, a first current spreader 328, a second current spreader 338, a third current spreader 348, a first color filter 347, a second color filter 347, a second color filter 357, a first connection layer 349, a second connection layer 359, a lower insulation layer 361, an upper insulation layer 371, an ohmic electrode 363a, through-hole paths 363b, 365a, 365b, 367a, 367b and electrode pads 373a, 373b, 373c, 373d.
[0432] [0432] The first substrate 321 can support the LED stacks 323, 333, 343. The first substrate 321 can be a growth substrate for the first 323 LED stack, for example, a GaAs substrate. In particular, the first substrate 321 may have conductivity.
[0433] [0433] The second substrate 341 can support the LED batteries 323, 333, 343. The LED batteries 323, 333, 343 are arranged between the first substrate 321 and the second substrate
[0434] [0434] In another exemplary embodiment, a plurality of third LED batteries 343 can be arranged on a single second substrate 341. The second LED stack 333, the first LED stack 323 and the first substrate 321 are arranged on each of the third LED batteries 343, whereby the light emitting device 300 has a single chip structure of a plurality of pixels.
[0435] [0435] In some exemplary embodiments, the second substrate 341 can be omitted and a bottom surface of the third LED stack 343 can be exposed. In this case, a rough surface can be formed on the bottom surface of the third 343 LED stack by surface textures.
[0436] [0436] Each of the first 323 LED stack, the second 333 LED stack and the 343 third LED stack includes a first semiconductor layer of conductivity type 323a, 333a and 343a, a second semiconductor layer of conductivity type 323b, 333b and 343b and an active layer interposed between them, respectively. The active layer can have a multi-quantum well structure.
[0437] [0437] LED cells that emit light with a shorter wavelength can be arranged closer to the second substrate 341. For example, the first 323 LED cell can be an inorganic light emitting diode adapted to emit red light, second stack of LED 333 can be an inorganic light emitting diode adapted to emit green light and the third 343 LED stack can be an inorganic light emitting diode adapted to emit blue light. The first 323 LED stack can include an AlGaInP based well layer, the second 333 LED stack can include an AlGaInP or AlGaInN based well layer and the third 343 LED stack can include an AlGaInN based well layer. However, inventive concepts are not limited to these. When the light-emitting device 300 includes a micro LED, which has a surface area of less than about 10,000 µm squared, as known in the art, or less than about 4,000 µm squared or 2,500 µm squared in other exemplary embodiments, the first 323 LED battery can emit any red, green and blue light, and the second and third 333 and 343 LED batteries can emit a light other than red, green and blue, without adversely affecting the operation, due to the small form factor of a micro LED.
[0438] [0438] In addition, the first semiconductor layer of conductivity type 323a, 333a and 343a of each of the LED cells 323, 333, 343 can be a n-type semiconductor layer and the second semiconductor layer of conductivity type 323b, 333b and 343b thereof can be a p-type semiconductor layer. According to the exemplary embodiment illustrated, an upper surface of the first LED stack 323 is a n-type semiconductor layer 323a, an upper surface of the second LED stack 333 is a n-type semiconductor layer 333a and an upper surface of the third cell 343b is a semiconductor type p 343b layer. In particular, only the semiconductor layers of the third 343 LED stack are stacked in a different sequence than the first and second LED stack
[0439] [0439] The first 323 LED battery, the second 333 LED battery and the third 343 LED battery can be stacked to overlap and can have substantially the same light area. In addition, in each of the LED cells 323, 333, 343, the first conductivity type semiconductor layer 323a, 333a and 343a can have substantially the same area as the second conductivity type semiconductor layer 323b, 333b and 343b. In particular, in each of the first LED stack 323 and the second LED stack 333, the first semiconductor layer of conductivity type 323a and 333a can completely overlap the second semiconductor layer of conductivity type 323b and 333b, respectively. In the third LED stack 343, an orifice h5 (see FIG. 45A) is formed in the second semiconductor layer of conductivity type 343b to expose the first semiconductor layer of conductivity type 343a and therefore the first semiconductor layer of conductivity type 343a has a slightly larger area than the second semiconductor layer of conductivity type 343b.
[0440] [0440] The first 323 LED stack is disposed in addition to the second 341 substrate, the second 333 LED stack is disposed under the first 323 LED stack and the third 343 LED stack is disposed under the second 333 LED stack. One Since the first 323 LED battery emits light with a longer wavelength than the second and third LED 333 and 343 batteries, the light generated from the first 323 LED battery can be emitted after passing through the second and third LED batteries 333 and 343 and the second substrate 341. Furthermore, since the second LED battery 333 emits light with a longer wavelength than the third LED battery 343, the light generated from the second battery of LEDs LED 333 can be emitted outside after passing through the third LED stack 343 and the second substrate 341.
[0441] [0441] The distributed Bragg reflector 322 can be arranged between the first substrate 321 and the first stack of LED 323. The distributed Bragg reflector 322 reflects the light generated from the first stack of LED 323 to prevent light from being lost through absorption by substrate 321. For example, the distributed Bragg reflector 322 can be formed by alternately stacking the semiconductor layers based on AlAs and AlGaAs one above the other.
[0442] [0442] The first transparent electrode 325 can be disposed between the first battery of LED 323 and the second battery of LED 333. The first transparent electrode 325 is in ohmic contact with the second semiconductor layer of conductivity type 323b of the first LED battery 323 and transmits light generated from the first 323 LED stack. The first transparent electrode 325 may include a metal layer or a transparent oxide layer, such as a layer of indium and tin oxide (ITO) or others.
[0443] [0443] The second transparent electrode 335 is in ohmic contact with the second semiconductor layer of conductivity type 333b of the second battery of LED 333. As shown in the drawings, the second transparent electrode 335 comes into contact with a lower surface of the second battery of LED 333 between the second stack of LED 333 and the third stack of LED 343. The second transparent electrode 335 can include a metal layer or a transparent conductive oxide layer in relation to red light and green light.
[0444] [0444] The third transparent electrode 345 is in ohmic contact with the second semiconductor layer of conductivity type 343b of the third LED stack 343. The third transparent electrode 345 can be arranged between the second LED stack 333 and the third LED stack 343 and comes in contact with the top surface of the third 343 LED stack. The third transparent electrode 345 may include a metal layer or a transparent conductive oxide layer in relation to red light and green light. The third transparent electrode 345 can also be transparent to blue light. Each of the second transparent electrode 335 and the third transparent electrode 345 are in ohmic contact with the p-type semiconductor layer of each of the LED cells to assist in spreading current. Examples of conductive oxide layers for the second and third transparent electrodes 335 and 345 can include SnO2, InO2, ITO, ZnO, IZO or others.
[0445] [0445] The first to third current spreaders 328, 338 and 348 can be arranged to spread current in the second semiconductor layers of conductivity type 323b, 333b and 343b from the first to the third LED batteries 323, 333 and 343. As shown in the drawing , the first current spreader 328 can be disposed on the second semiconductor layer of conductivity type 323b exposed through the first transparent electrode 325, the second current spreader 338 can be disposed on the second semiconductor layer of conductivity type 333b exposed through the second electrode transparent 335 and the third current spreader 348 can be disposed on the second semiconductor layer of conductivity type 343b exposed through the third transparent electrode 345. As shown in Fig. 38A, each of the first to third current spreaders 328, 338 and 348 can be arranged along one edge of each of the first to third LED batteries 323, 333 and 343. Thus, each of the first to third current spreaders 328, 338 and 348 may have a substantially ring shape to enclose a center of each stack of LEDs, but the inventive concepts are not limited to these and may be substantially straight or curve. In addition, the first to third chain spreaders 328, 338 and 348 can be arranged to overlap, without being limited to these.
[0446] [0446] The first to the third current spreader 328, 338 and 348 can be separated from the first to the third transparent electrode 325, 335 and 345. Therefore, a gap can be formed between a lateral surface of the first to the third current spreader 328 , 338 and 348 and the first to the third transparent electrode 325, 335 and 345. However, the inventive concepts are not limited to these and at least one of the first to the third current spreader 328, 338 and 348 can contact the first to the third transparent electrode 325, 335 and
[0447] [0447] The first to the third current spreader 328, 338 and 348 can include a material with a higher electrical conductivity than the first to the third transparent electrode 325, 335 and 345. In this way, the current can spread evenly over wide regions of the second semiconductor layers of conductivity type 323b, 333b and 343b.
[0448] [0448] The ohmic electrode 346 is in ohmic contact with the first semiconductor layer of conductivity type 343a of the first LED stack layer 343. The ohmic electrode 346 can be disposed in the first semiconductor layer of conductivity type 343a exposed through the third transparent electrode 345 and in the second semiconductor layer of conductivity type 343b. The ohmic electrode 346 can be formed from Ni / Au / Ti or Ni / Au / Ti / Ni, for example. When a surface of the ohmic electrode 346 is exposed during the etching process, a Ni layer can be formed on the surface of the ohmic electrode 346 and function as a recording interrupt layer. The ohmic electrode 346 can be formed to take various forms. In an exemplary embodiment, the ohmic electrode 346 can be substantially elongated to function as a current spreader. In some exemplary embodiments, the ohmic electrode 346 can be omitted.
[0449] [0449] The first color filter 347 can be disposed between the third transparent electrode 345 and the second battery of LED 333 and the second color filter 357 can be disposed between the second battery of LED 333 and the first battery of LED 323. The first color filter 347 transmits light generated from the first and second LED batteries 323 and 333 while reflecting the light generated from the third LED battery 343. The second color filter 357 transmits light generated from the first battery of LEDs. LED 323 while reflecting the light generated from the second stack of LED 333. Therefore, the light generated from the first stack of LED 323 can be emitted out through the second stack of LED 333 and the third stack of LED 343, and the light generated from the second stack of LED 333 can be emitted out through the third stack of LED 343. In addition, it is possible to prevent light loss by preventing the light generated from the second stack of LED 333 from entering the first 323 LED stack or the light generated from the third battery of LED 343 enter the second battery of LED 333.
[0450] [0450] In some exemplary embodiments, the second color filter 357 can reflect the light generated from the third 343 LED stack.
[0451] [0451] The first and second color filters 347, 357 can be, for example, a low pass filter that allows light in a low frequency band, for example, a long wavelength band to pass through it , a bandpass filter that allows light in a predetermined wavelength range, or a bandpass filter that prevents light in a predetermined wavelength range from passing through it. In particular, each of the first and second color filters 347 and 357 can be formed by alternately stacking layers of insulation with different refractive indices one above the other, such as TiO2 and SiO2, for example. In particular, each of the first and second color filters 347 and 357 can include a distributed Bragg reflector (DBR). In addition, an interrupted band of the distributed Bragg reflector can be controlled by adjusting the thicknesses of the TiO2 and SiO2 layers. The low-pass filter and the band-pass filter can also be formed by alternately stacking layers of insulation with different refractive indices one above the other.
[0452] [0452] The first link layer 349 couples the second stack of LED 333 to the third stack of LED 343. The first link layer 349 can couple the first color filter 347 to the second transparent electrode 335 between the first color filter
[0453] [0453] The second layer of connection 359 couples the second battery of LED 333 to the first battery of LED 323. As shown in the drawings, the second layer of connection 359 can be arranged between the second color filter 357 and the first transparent electrode 325 The second bonding layer 359 can be formed from substantially the same material as the first bonding layer 349.
[0454] [0454] Orifices h1, h2, h3, h4, h5 are formed through the first substrate 321. Orifice h1 can be formed through the first substrate 321, the distributed Bragg reflector 322 and the first LED stack 323 to expose the first transparent electrode 325. Orifice h2 can be formed through the first substrate 321, the distributed Bragg reflector 322, the first transparent electrode 325, the second connection layer 359 and the second color filter 357 to expose the first type semiconductor layer conductivity 333a of the second 333 LED battery
[0455] [0455] Orifice h3 can be formed through the first substrate 321, the distributed Bragg reflector 322, the first transparent electrode 325, the second connection layer 359 and the second color filter 357 and the second stack of LED 333 to expose the second transparent electrode 335. Orifice h4 can be formed through the first substrate 321, the distributed Bragg reflector 322, the first transparent electrode 325, the second connection layer 359, the second color filter 357, the second LED stack 333, the second transparent electrode 335, the first connection layer 349 and the first color filter 347 to expose the third transparent electrode 345. The orifice h5 can be formed through the first substrate 321, the distributed Bragg reflector 322, the first transparent electrode 325 , the second connection layer 359, the second color filter 357, the second battery of LED 333, the second transparent electrode 335, the first connection layer 349 and the first color filter 347 for exposing the ohmic electrode 346. When the ohmic electrode 346 is omitted in some exemplary embodiments, the first semiconductor layer of conductivity type 343a can be exposed through hole h5.
[0456] [0456] Although the holes h1, h3 and h4 are illustrated as being separated from each other to expose the first to the third transparent electrode 325, 335 and 345, respectively, the inventive concepts are not limited to this and the first to the third transparent electrode 325, 335 and 345 can be exposed through a single hole.
[0457] [0457] Furthermore, although the first to the third transparent electrodes 325, 335 and 345 are illustrated as exposed by the holes h1, h3 and h4, in some exemplary embodiments, the first to the third current spreaders 328, 338 and 348 can be exposed .
[0458] [0458] The bottom insulation layer 361 covers the side surfaces of the first substrate 321 and the first to the third LED stacks 323, 333, 343, while covering an upper surface of the first substrate 321. The lower insulation layer 361 also covers the side surfaces of holes h1, h2, h3, h4, h5. However, the bottom insulation layer 361 can be subjected to patterns to expose a bottom of each of the holes h1, h2, h3, h4, h5. In addition, the lower insulation layer 361 can also be subjected to patterns to expose the upper surface of the first substrate 321.
[0459] [0459] The ohmic electrode 363a is in ohmic contact with the upper surface of the first substrate 321. The ohmic electrode 363a can be formed in an exposed region of the first substrate 321, which is exposed by the pattern of the lower insulation layer 361. The electrode ohmic 363a can be formed from Au-Te alloys or Au-Ge alloys, for example. Each through-hole path 363b, 365b and 367b can be connected to the first to the third transparent electrode 325, 335 and 345, and can be connected to the first to the third current spreaders 328, 338 and 348, respectively.
[0460] [0460] The through hole paths 363b, 365a, 365b, 367a, 367b are arranged in holes h1, h2, h3, h4, h5. Through hole 363b can be arranged in hole h1 and can be connected to the first transparent electrode 325. Through hole 365a can be arranged in hole h2 and be in ohmic contact with the first semiconductor layer of the conductivity type 333a. Through hole 365b can be arranged in hole h3 and can be electrically connected to the second transparent electrode 335. Through hole 367a can be arranged in hole h5 and can be electrically connected to the first semiconductor layer of the conductivity type 343a. For example, through-hole path 367a can be electrically connected to ohmic electrode 345 through hole h5. Through hole 367b can be arranged in hole h4 and can be connected to the third transparent electrode 345. Through hole 363b, 365b and 367b can be connected to the first through the third transparent electrode 325, 335 and 345, or it can be connected to the first to the third chain spreader 328, 338 and 348, respectively.
[0461] [0461] The upper insulation layer 371 covers the lower insulation layer 361 and the ohmic electrode 363a. The upper insulation layer 371 can cover the lower insulation layer 361 on the sides of the first substrate 321 and the first to the third LED stacks 323, 333 and 343. An upper surface of the lower insulation layer 361 can be covered by the insulation layer upper 371. The upper insulating layer 371 can have an opening 371a to expose the ohmic electrode 363a and can have openings to expose the through hole paths 363b, 365a, 365b, 367a and 367b.
[0462] [0462] The lower insulation layer 361 or the upper insulation layer 371 may be formed of silicon oxide or silicon nitride, but is not limited to these. For example, the bottom insulation layer 361 or the top insulation layer 371 can be a distributed Bragg reflector formed by stacking insulation layers with different refractive indices. In particular, the top insulating layer 371 can be a light reflective layer or a light blocking layer.
[0463] [0463] The electrode pads 373a, 373b, 373c, 373d are arranged in the upper insulating layer 371 and are electrically connected to the first to third LED batteries 323, 333, 343. For example, the first electrode pad 373a is electrically connected to the ohmic electrode 363a exposed through the opening 371a of the upper insulation layer 371, and the second electrode pad 373b is electrically connected to the exposed orifice path 365a exposed through the opening of the upper insulation layer 371. In addition, the third electrode pad 373c is electrically connected to the exposed orifice path 367a exposed through the opening of the upper insulating layer 371. A common electrode pad 373d is commonly electrically connected to the orifice path 363b, 365b and 367b.
[0464] [0464] Therefore, the common electrode pad 373d is normally electrically connected to the second semiconductor layers of conductivity type 323b, 333b, 343b from the first to the third LED batteries 323, 333, 343 and each of the electrode pads 373a , 373b, 373c is electrically connected to the first semiconductor layers of conductivity type 323a, 333a, 343a from the first to the third LED batteries 323, 333, 343, respectively.
[0465] [0465] According to the exemplary mode illustrated, the first 323 LED battery is electrically connected to the 373d and 373a electrode pads, the second 333 LED battery is electrically connected to the 373d and 373b electrode pads and the third LED battery 343 is electrically connected to the 373d and 373c electrode pads. Therefore, the anodes of the first 323 LED battery, the second 333 LED battery, and the third 343 LED battery are commonly electrically connected to the 373d electrode pad, and their cathodes are electrically connected to the first to the third 373a electrode pad, 373b, and 373c, respectively. Therefore, the first to third LED batteries 323, 333, 343 can be driven independently.
[0466] [0466] FIGS. 39A, 39B, 40A, 40B, 41A, 41B, 42, 43, 44, 45A, 45B, 46A, 46B, 47A, 47A, 47B, 48A, 48B, 49A and 49B are schematic plan views and cross-sectional views that illustrate a method of making a light-emitting device for a screen according to an exemplary embodiment. In the drawings, each plan view corresponds to FIG. 38A, and each cross-sectional view is taken along line A-A of the corresponding plan view. FIGS. 39B and 40B are cross-sectional views taken along line B-B of FIGS. 39A and 40A, respectively.
[0467] [0467] Referring to FIGS. 39A and 39B, a first LED stack 323 is grown on a first substrate 321. The first substrate 321 can be a GaAs substrate, for example. The first LED stack 323 may include semiconductor layers based on AlGalnP and includes a first semiconductor layer of conductivity type 323a, an active layer and a second semiconductor layer of conductivity type 323b. The first type of conductivity can be type n and the second type of conductivity can be type p. A distributed Bragg reflector 322 can be formed prior to the growth of the first LED stack 323. The distributed Bragg reflector 322 can have a stack structure formed by repeatedly stacking layers of AlAs / AlGaAs, for example.
[0468] [0468] A first transparent electrode 325 can be formed in the second semiconductor layer of conductivity type 323b. The first transparent electrode 325 can be formed by a transparent oxide layer, such as tin and indium oxide (ITO), a transparent metal layer or others.
[0469] [0469] The first transparent electrode 325 can be formed to have an opening to expose the second semiconductor layer of conductivity type 323b and a first current spreader 328 can be formed in the opening. The first transparent electrode 325 can be standardized by photolithography and engraving techniques, for example, which can form the opening for the exposure of the second semiconductor layer of conductivity type 323b. The opening of the first transparent electrode 325 can define a region in which the first current spreader 328 can be formed.
[0470] [0470] Although FIG. 39A show the first chain spreader 328 as having substantially a rectangular shape, the inventive concepts are not limited to these. For example, the first chain spreader 328 can take various shapes, such as an elongated line or a curved line shape. The first current spreader 328 can be formed by the lifting technique or similar, and one side of it can be separated from the first transparent electrode 325. The first current spreader 328 can be formed to have the same thickness or thickness similar to the first electrode transparent 325.
[0471] [0471] Referring to FIGS. 40A and 40B, a second stack of LED 333 is grown on a substrate 331 and a second transparent electrode 335 is formed on the second stack of LED 333. The second stack of LED 333 can include semiconductor layers based on AlGaInP or AlGaInN and can include a first conductivity type semiconductor layer 333a, an active layer and a second conductivity type semiconductor layer 333b. The substrate 331 may be a substrate capable of growing layers of semiconductors based on AlGaInP, for example, a substrate GaAs or a GaP, or a substrate capable of growing layers of semiconductors based on AlGaInN, for example, a sapphire substrate. The first type of conductivity can be type n and the second type of conductivity can be type p. A composition ratio of Al, Ga and In for the second battery of LED 333 can be determined so that the second battery of LED 333 can emit green light, for example. In addition, when the GaP substrate is used, a pure GaP layer or a nitrogen (N) doped GaP layer is formed in the GaP to obtain green light. The second transparent electrode 335 may be in ohmic contact with the second semiconductor layer of conductivity type 333b. The second transparent electrode 335 can be formed by a metal layer or a conductive oxide layer, such as SnO2, InO2, ITO, ZnO, IZO and the like.
[0472] [0472] The second transparent electrode 335 can be formed to have an opening to expose the second semiconductor layer of conductivity type 333b and a second current spreader 338 can be formed in the opening. The second transparent electrode 335 can be standardized by photolithography and engraving techniques, for example, which can form the opening for the exposure of the second semiconductor layer of conductivity type 333b. The opening of the second transparent electrode 335 can define a region for the second current spreader 338 to be formed.
[0473] [0473] Although FIG. 40A show the second chain spreader 338 as having a substantially rectangular shape, the inventive concepts are not limited to this. For example, the second chain spreader 338 can take various shapes, such as substantially an elongated or curved line shape. The second current spreader 338 can be formed by the lifting technique or the like, and one side of it can be separated from the second transparent electrode 335. The second current spreader 338 can be formed to have the same or similar thickness as the second electrode transparent 335.
[0474] [0474] The second chain spreader 338 may have the same shape and size as the first chain spreader 328, without being limited to it.
[0475] [0475] Referring to FIGS. 41A and 41B, a third LED stack 343 is grown on a second substrate 341 and a third transparent electrode 345 is formed on the third LED stack 343. The third LED stack 343 can include semiconductor layers based on AlGalnN and can include a first conductivity type semiconductor layer 343a, an active layer and a second conductivity type semiconductor layer 343b. The first type of conductivity can be type n and the second type of conductivity can be type p.
[0476] [0476] The second substrate 341 is a substrate capable of growing GaN-based semiconductor layers, and may be different from the first substrate 321. A composition ratio of AlGaInN to the third LED stack 343 is determined to allow the third 343 LED battery emits blue light, for example. The third transparent electrode 345 is in ohmic contact with the second semiconductor layer of conductivity type 343b. The third transparent electrode 345 can be formed of a conductive oxide layer, such as SnO2, InO2, ITO, ZnO, IZO and the like.
[0477] [0477] The third transparent electrode 345 can be formed to have an opening to expose the first semiconductor layer of conductivity type 343a and an opening to expose the second semiconductor layer of conductivity type 343b. The opening for exposing the first semiconductor layer of conductivity type 343a can define a region in which an ohmic electrode 346 can be formed and the opening for exposing the second semiconductor layer of conductivity type 343b can define a region for which a third chain spreader 348 can be formed.
[0478] [0478] The third transparent electrode 345 can be standardized by photolithography and engraving techniques, for example, which can form the openings for the exposure of the second semiconductor layer of conductivity type 343b. Thereafter, the first semiconductor layer of conductivity type 343a can be exposed by partial conditioning of the second semiconductor layer of conductivity type 343b, and the ohmic electrode 346 can be formed in an exposed region of the first semiconductor layer of conductivity type 343a. The ohmic electrode 346 can be formed from a metal layer and in ohmic contact with the first semiconductor layer of conductivity type 343a. For example, the ohmic electrode 346 can be formed from a multilayer structure of Ni / Au / Ti or Ni / Au / Ti / Ni. The ohmic electrode 346 is electrically separated from the third transparent electrode 345 and the second semiconductor layer of conductivity type 343b.
[0479] [0479] The third current spreader 348 is formed in an exposed region of the second semiconductor layer of conductivity type 343b. Although FIG. 41A show the third chain spreader 348 as having substantially a rectangular shape, the inventive concepts are not limited to this. For example, the third chain spreader 348 can take various shapes, such as substantially an elongated or curved line shape. The third current spreader 348 can be formed by the lifting technique or the like, and one side of it can be separated from the third transparent electrode 345. The third current spreader 348 can be formed to have the same thickness or thickness similar to the third electrode transparent 345.
[0480] [0480] The third chain spreader 348 may be substantially the same shape and size as the first or second chain spreader 328 or 338, without being limited thereto.
[0481] [0481] Then, a first color filter 347 is formed on the second transparent electrode 345. Since the first color filter 347 is substantially the same as that described with reference to FIG. 38A and FIG. 38B, detailed descriptions will be omitted to avoid redundancy.
[0482] [0482] Referring to FIG. 42, the second LED stack 333 of FIG. 40A and FIG. 40B is connected to the third LED stack 343 of FIG. 41A and FIG. 41B, and the second substrate 331 is removed therefrom.
[0483] [0483] The first color filter 347 is connected to the second transparent electrode 335 for facing. For example, layers of bonding material can be formed on the first color filter 347 and the second transparent electrode 335 and are bonded together to form a first bonding layer 349. The layers of the bonding material can be transparent layers of material organic or transparent layers of inorganic material. Examples of the organic material can include SU8, poly (methyl methacrylate) (PMMA), polyimide, Parylene, benzocyclobutene (BCB) or others, and examples of the inorganic material can include Al2O3, SiO2, SiNx or others. More particularly, the first bonding layer 349 can be formed of spin-on-glass (SOG).
[0484] [0484] In addition, the second chain spreader 338 can be arranged to overlap the third chain spreader 348, without being limited thereto.
[0485] [0485] Thereafter, substrate 331 can be removed from the second stack of LED 333 by laser lifting or chemical lifting. As such, an upper surface of the first conductivity type semiconductor layer 333a of the second LED stack 333 is exposed. The exposed surface of the first conductivity type semiconductor layer 333a can be subject to texturing.
[0486] [0486] Referring to FIG. 43, a second color filter 357 is formed in the second stack of LED 333. The second color filter 357 can be formed by alternately stacking layers of insulation with different refractive indices and is substantially the same as that described with reference to FIG. 38A and FIG. 38B, and therefore the detailed descriptions will be omitted.
[0487] [0487] Subsequently, with reference to FIG. 44, the first LED stack 323 of FIG. 39 is connected to the second battery of LED 333. The second color filter 357 can be connected to the first transparent electrode 325 to face each other. For example, layers of bonding material can be formed in the second color filter 357 and the first transparent electrode 325 and are bonded together to form a second bonding layer 359. The layers of the bonding material are substantially the same as those described with reference to the first connection layer 349 and, therefore, detailed descriptions will be omitted.
[0488] [0488] Meanwhile, the first spreader 328 can be arranged to overlap the second or third current spreader 338 or 348, without being limited to it.
[0489] [0489] Referring to FIG. 45A and FIG. 45B, holes h1,
[0490] [0490] Hole h1 exposes the first transparent electrode 325, hole h2 exposes the first semiconductor layer of conductivity type 333a, hole h3 exposes the second transparent electrode 335, hole h4 exposes the third transparent electrode 345 and hole h5 exposes an ohmic electrode 346. When hole h5 exposes the ohmic electrode 346, an upper surface of the ohmic electrode 346 may include an anti-etching layer, for example, a Ni layer. In an exemplary embodiment, the holes h1, h3 and h4 can expose the first to the third chain spreaders 328, 338 and 348, respectively. In addition, hole h5 can expose the first semiconductor layer of conductivity type 343a.
[0491] [0491] The insulation ditch can expose the second substrate 341 along a periphery of each of the first to the third LED stacks 323, 333 and 343. Although FIG. 45B show the insulation ditch being formed to expose the second substrate 341, in some exemplary embodiments, the insulation ditch can be formed to expose the first conductivity type semiconductor layer 343a. The orifice h5 can be formed together with the insulation ditch by the engraving technique or the like, without being limited to it.
[0492] [0492] The holes h1, h2, h3, h4, h5 and insulation trenches can be formed by photolithography and engraving techniques, and the formation sequence is not particularly limited. For example, a shallower orifice may be formed before a deeper orifice, or vice versa. The insulation ditch can be formed before or after the formation of the holes h1, h2, h3, h4, h5. Alternatively, the insulation ditch can be formed together with the orifice h5, as described above.
[0493] [0493] Referring to FIG. 46A and FIG. 46B, a lower insulation layer 361 is formed on the first substrate 321. The lower insulation layer 361 can cover side surfaces of the first substrate 321 and side surfaces of the first to the third LED stacks 323, 333, 343, which are exposed through the insulation ditch.
[0494] [0494] The bottom insulation layer 361 can also cover the side surfaces of the holes h1, h2, h3, h4, h5. The lower insulation layer 361 is subjected to standardization in order to expose a bottom of each of the holes h1, h2, h3, h4, h5.
[0495] [0495] The bottom insulation layer 361 can be formed of silicon oxide or silicon nitride, but the inventive concepts are not limited to these. The insulation layer 361 can include a distributed Bragg reflector.
[0496] [0496] Subsequently, through-hole paths 363b, 365a, 365b, 367a, 367b are formed in holes h1, h2, h3, h4, h5. The through-hole paths 363b, 365a, 365b, 367a, 367b can be formed by electrical plating or the like. For example, a seed layer can be formed first within the orifices h1, h2, h3, h4, h5 and through-hole paths 363b, 365a, 365b, 367a, 367b can be formed by coating with copper using the seed. The seed layer can be formed by Ni / Al / Ti / Cu, for example.
[0497] [0497] Referring to FIG. 47A and FIG. 47B, the upper surface of the first substrate 321 can be exposed by modeling the lower insulation layer 361. The process of standardizing the lower insulation layer 361 to expose the upper surface of the first substrate 321 can be carried out after standardizing the lower insulation layer 361 to expose the bottoms of holes h1, h2, h3, h4, h5.
[0498] [0498] A substantial portion of the upper surface of the first substrate 321 can be exposed, for example, at least half the area of the light emitting device.
[0499] [0499] Thereafter, an ohmic electrode 363a is formed on the exposed upper surface of the first substrate 321. The ohmic electrode 363a can be formed from a conductive layer, such as Au-Te alloys or Au-Ge alloys, for example, and be in ohmic contact with the first substrate 321.
[0500] [0500] As shown in Fig. 47A, the ohmic electrode 363a is separated from the orifice pathways 363b, 365a, 365b, 367a, 367b.
[0501] [0501] Referring to FIG. 48A and FIG. 48B, an upper insulation layer 371 is formed to cover the lower insulation layer 361 and the ohmic electrode 363a. The upper insulating layer 371 can also cover the lower insulating layer 361 on the side surfaces of the first to the third LED stacks 323, 333, 343 and the first substrate 321. The upper insulating layer 371 can be patterned to form openings that expose the orifice pathways 363b, 365a, 365b, 367a, 367b together with an opening 371a exposing the ohmic electrode 363a.
[0502] [0502] The top insulating layer 371 can be formed by a transparent oxide layer, such as silicon oxide or silicon nitride, but the inventive concepts are not limited to these. For example, the top insulation layer
[0503] [0503] Referring to FIG. 49A and FIG. 49B, electrode pads 373a, 373b, 373c, 373d are formed in the upper insulating layer 371. Electrode pads 373a, 373b, 373c, 373d may include first to third electrode pads 373a, 373b, 373c and a pad of common electrode 373d.
[0504] [0504] The first electrode pad 373a can be connected to the ohmic electrode 363a exposed through the opening 371a of the upper insulation layer 371, the second electrode pad 373b can be connected to the through hole path of 365a and the third electrode 373c can be connected to the through hole 367a. The common electrode pad 373d can normally be connected to through-hole paths 363b, 365b, 367b.
[0505] [0505] The electrode pads 373a, 373b, 373c, 373d are electrically separated from each other and thus each of the first to third LED batteries 323, 333, 343 is electrically connected to two electrode pads to be operated independently .
[0506] [0506] Thereafter, the second substrate 341 is divided into regions for each light emitting device, thus completing the light emitting device 300. As shown in Fig. 49A, the electrode pads 373a, 373b, 373c, 373d can be arranged in four corners of each light emitting device 300. The electrode pads 373a, 373b, 373c, 373d can be substantially rectangular in shape, but the inventive concepts are not limited to these.
[0507] [0507] Although the second substrate 341 is described as being divided, in some exemplary embodiments, the second substrate 341 can be removed. In this case, an exposed surface of the first semiconductor layer of conductivity type 343 can be subjected to texturing.
[0508] [0508] FIG. 50A and FIG. 50B are a schematic plan view and a cross-sectional view of a light-emitting device 302 for a display, according to another exemplary embodiment, respectively.
[0509] [0509] Referring to FIG. 50A and FIG. 50B, the light-emitting device 302 according to an exemplary embodiment is substantially similar to the light-emitting device 300 described with reference to FIG. 38A and FIG. 38B, except that the anodes of the first to the third LED batteries 323, 333, 343 are independently connected to the first to the third electrode pads 3173a, 3173b, 3173c, and their cathodes are electrically connected to a common electrode 3173d.
[0510] [0510] More particularly, the first electrode pad 3173a is electrically connected to the first transparent electrode 325 through a through-hole path 3163b, the second electrode pad 3173b is electrically connected to the second transparent electrode 335 through a path via through hole 3165b and the third electrode pad 3173c is electrically connected to the third transparent electrode 345 through a through hole 3167b. The common electrode pad 3173d is electrically connected to an ohmic electrode 3163a exposed through opening 371a of the upper insulating layer 371 and is also electrically connected to the first semiconductor layers of conductivity type 333a and 343a of the second 333 LED stack and the third battery of LED 345 through through-hole paths 3165a, 3167a. For example, the 3165a through-hole path can be connected to the first conductivity type semiconductor layer 333a, and the 3175a through-hole path can be connected to the ohmic electrode 346 in ohmic contact with the first semiconductor layer of conductivity. conductivity type 343a.
[0511] [0511] Each of the light-emitting devices 300, 302, according to the exemplary modalities, includes the first to third LED batteries 323, 333, 343, which emit red, green and blue light, respectively, and therefore can be used as a pixel on a display device. As described in FIG. 37, the display device can be realized by arranging a plurality of light-emitting devices 300 or 302 on circuit board 301. As each of the light-emitting devices 300, 302 includes the first to third LED batteries 323, 333, 343 , you can increase the area of a subpixel by one pixel. In addition, the first to third LED batteries 323, 333, 343 can be mounted on the circuit board by mounting a light-emitting device, thereby reducing the number of assembly processes.
[0512] [0512] As described in FIG. 37, the light-emitting devices mounted on the circuit board 301 can be activated passively by matrix or by active matrix.
[0513] [0513] FIG. 51 is a schematic plan view of a display device according to an exemplary embodiment.
[0514] [0514] Referring to FIG. 51, the display device, according to an exemplary embodiment, includes a 401 circuit board and a plurality of light-emitting devices
[0515] [0515] Circuit board 401 may include a circuit for passively driving the matrix or active driving the matrix. In an exemplary embodiment, circuit board 401 may include interconnect lines and resistors. In another exemplary embodiment, circuit board 401 may include interconnect lines, transistors and capacitors. Circuit board 401 may also have electrode pads arranged on an upper surface of the circuit board to allow electrical connection to the circuit on it.
[0516] [0516] The light-emitting devices 400 are arranged on the circuit board 401. Each of the light-emitting devices 400 can constitute a pixel. The light-emitting device 400 can include electrode pads 473a, 473b, 473c and 473d, which are electrically connected to the circuit board 401. In addition, the light-emitting device 400 can include a substrate 441 disposed on an upper surface thereof . Since the light-emitting devices 400 are separated from each other, the substrates 441 disposed on the upper surfaces of the light-emitting devices 400 are also separated from each other.
[0517] [0517] Details of the light emitting device 400 will be described with reference to FIG. 52A and FIG. 52B. FIG. 52A is a schematic plan view of a light-emitting device 400 for a display, according to an exemplary embodiment, and FIG. 52B is a schematic cross-sectional view along a line A-A of FIG. 52A. Although the electrode pads 473a, 473b, 473c and 473d are illustrated and described as arranged on the upper side of the light emitting device, in some exemplary embodiments, the light emitting device 400 can be connected to circuit board 401, in this case, the electrode pads 473a, 473b, 473c and 473d can be arranged on its underside.
[0518] [0518] Referring to FIG. 52A and FIG. 52B, the light-emitting device 400 may include a first substrate 421, a second substrate 441, a distributed Bragg reflector 422, a first LED stack 423, a second LED stack 433, a third LED stack 443, a first electrode transparent 425, a second transparent electrode 435, a third transparent electrode 445, an ohmic electrode 446, a first current spreader 428, a second current spreader 438, a third current spreader 448, a first color filter 447, a second color filter 457, a first connection layer 449, a second connection layer 459, a lower insulation layer 461, an upper insulation layer 471, an ohmic electrode 463a, through-hole paths 463b, 465a, 465b, 467a and 467b, heat tubes 469 and electrode pads 473a, 473b, 473c and 473d.
[0519] [0519] The first substrate 421 can support the LED cells 423, 433 and 443. The first substrate 421 can be a growth substrate for the growth of the first LED stack 423, for example, a GaAs substrate. In particular, the first substrate 421 can have conductivity.
[0520] [0520] The second substrate 441 can support the LED cells 423, 433 and 443. The LED cells 423, 433 and 443 are arranged between the first substrate 421 and the second substrate
[0521] [0521] In another exemplary embodiment, a plurality of third LED batteries 43 can be arranged on a single second substrate 441. The second LED stack 433, the first LED stack 423 and the first substrate 421 are arranged on each one. third LED batteries 43, whereby the light emitting device 400 has a single chip structure of a plurality of pixels.
[0522] [0522] In some exemplary embodiments, the second substrate 441 can be omitted and a bottom surface of the third LED stack 443 can be exposed. In this case, a rough surface can be formed on the bottom surface of the third stack of LED 443 by surface textures.
[0523] [0523] Each of the first LED stack 423, the second LED stack 433 and the third LED stack 443 include a first semiconductor layer of conductivity type 423a, 433a and 443a, a second semiconductor layer of conductivity type 423b, 433b and 443b and an active layer interposed between them, respectively. The active layer can have a multi-quantum well structure.
[0524] [0524] The LED cells can emit light with a shorter wavelength, being placed closer to the second substrate 441. For example, the first LED cell 423 can be an inorganic light emitting diode adapted to emit red light, second battery of LED 433 can be an inorganic light emitting diode adapted to emit green light, and the third battery of LED 443 can be an inorganic light emitting diode adapted to emit blue light. The first stack of LED 423 can include a well layer based on AlGaInP, the second stack of LED 433 can include a well layer based on AlGaInP or AlGaInN and the third stack of LED 443 can include a well layer based on AlGaInN. However, inventive concepts are not limited to these. When the light-emitting device 400 includes a micro LED, which has a surface area of less than about 10,000 µm square, as known in the art, or less than about 4,000 µm square or 2,500 µm square in other exemplary embodiments, the first 423 LED battery can emit any red, green and blue light, and the second and third 433 and 443 LED batteries can emit a light other than red, green and blue, without adversely affecting the operation, due to the small form factor of a micro LED.
[0525] [0525] In addition, the first semiconductor layer of conductivity type 423a, 433a and 443a of each of the LED cells 423, 433 and 443 can be a n-type semiconductor layer and the second semiconductor layer of conductivity type 423b, 433b and 443b thereof can be a p-type semiconductor layer. In the exemplary embodiment illustrated, an upper surface of the first LED stack 423 is a semiconductor layer of type 423a, an upper surface of the second LED stack 433 is a semiconductor layer of type 433a and an upper surface of the third LED stack 443 it is a p 443b type semiconductor layer. In particular, only the semiconductor layers of the third LED stack 443 are stacked in a different sequence than the first and second LED cells 423 and 433. The first semiconductor layer of conductivity type 443a of the third LED stack 443 can be subjected to surface texturing to improve the efficiency of light extraction. In some exemplary embodiments, the first conductivity type semiconductor layer 433a of the second LED stack 433 can also be subjected to surface texturing.
[0526] [0526] The first 423 LED battery, the second 433 LED battery and the third 443 LED battery can be stacked to overlap and can have substantially the same light area. In addition, in each of the LED cells 423, 433 and 443, the first conductivity type semiconductor layer 423a, 433a and 443a can have substantially the same area as the second conductivity type semiconductor layer 423b, 433b, 443b, respectively. In particular, in each of the first LED stack 423 and the second LED stack 433 according to an exemplary embodiment, the first semiconductor layer of conductivity type 423a or 433a can completely overlap the second layer of semiconductor type conductivity 423b or 433b. In the third LED stack 443, an orifice h5 is formed in the second semiconductor layer of conductivity type 443b to expose the first semiconductor layer of conductivity type 443a and therefore the first semiconductor layer of conductivity type 443a has a slightly area greater than the second semiconductor layer of conductivity type 443b.
[0527] [0527] The first 423 LED stack is disposed in addition to the second 441 substrate, the second 433 LED stack is disposed under the first 423 LED stack and the third 443 LED stack is disposed under the second 433 LED stack. One Since the first 423 LED battery can emit light with a longer wavelength than the second and third 433 and 443 LED batteries, the light generated from the first 423 LED battery can be emitted outside after passing through the second and third batteries of LED 433 and 443 and second substrate 441. In addition, since the second battery of LED 433 can emit light with a longer wavelength than the third battery of LED 443, the light generated from the second battery of LED 433 can be emitted outside after passing through the third stack of LED 443 and the second substrate 441.
[0528] [0528] The distributed Bragg reflector 422 can be arranged between the first substrate 421 and the first stack of LED 423. The distributed Bragg reflector 422 reflects the light generated from the first stack of LED 423 to prevent light from being lost through absorption by the substrate 421. For example, the distributed Bragg reflector 422 can be formed by alternately stacking the semiconductor layers based on AlAs and AlGaAs one above the other.
[0529] [0529] The first transparent electrode 425 can be arranged between the first battery of LED 423 and the second battery of LED 433. The first transparent electrode 425 is in ohmic contact with the second semiconductor layer of conductivity type 423b of the first LED battery 423 and transmits light generated from the first 423 LED stack. The first transparent electrode 425 may include a metal layer or a transparent oxide layer, such as a layer of indium and tin oxide (ITO) or others.
[0530] [0530] The second transparent electrode 435 is in ohmic contact with the second semiconductor layer of conductivity type 433b of the second battery of LED 433. As shown in the drawings, the second transparent electrode 435 comes into contact with a lower surface of the second battery of LED 433 between the second battery of LED 433 and the third battery of LED 443. The second transparent electrode 435 can include a metal layer or a layer of conductive oxide that is transparent to red light and green light.
[0531] [0531] The third transparent electrode 445 is in ohmic contact with the second semiconductor layer of conductivity type 443b of the third LED cell 443. The third transparent electrode 445 can be arranged between the second LED cell 433 and the third LED cell 443 and contacts the upper surface of the third 443 LED stack. The third transparent electrode 445 may include a metal layer or a transparent conductive oxide layer for red light and green light. The third transparent electrode 445 can also be transparent to blue light. Each of the second transparent electrode 435 and the third transparent electrode 445 is in ohmic contact with the p-type semiconductor layer of each of the LED cells to assist in spreading current. Examples of conductive oxide layers for the second and third transparent electrodes 435 and 445 can include SnO2, InO2, ITO, ZnO, IZO or others.
[0532] [0532] The first to third current spreaders 428, 438 and 448 can be arranged to spread current in the second semiconductor layers of conductivity type 423b, 433b and 443b from the first to the third LED batteries 423, 433 and 443. As shown in the drawing , the first current spreader 428 can be disposed on the second semiconductor layer of conductivity type 423b exposed through the first transparent electrode 425, the second current spreader 438 can be disposed on the second semiconductor layer of conductivity type 433b exposed through the second electrode transparent 435 and the third current spreader 448 can be disposed on the second semiconductor layer of conductivity type 443b exposed through the third transparent electrode 445. As shown in Fig. 52A, each of the first to third current spreaders 428, 438 and 448 can be arranged along one edge of each of the first to the third LED batteries 423, 433 and 443. So, each of the first to third current spreaders 428, 438 and 448 may have a substantially rectangular shape to surround a center of each LED stack, but the inventive concepts are not limited to these, and current spreaders may have several shapes, such as substantially an elongated or curved line shape. In addition, the first to third chain spreaders 428, 438 and 448 can be arranged to overlap, without being limited to these.
[0533] [0533] The first to the third current spreader 428, 438 and 448 can be separated from the first to the third transparent electrode 425, 435 and 445. Therefore, a gap can be formed between a side surface of the first to the third current spreader 428 , 438 and 448 and the first to the third transparent electrode 425, 435 and 445. However, the inventive concepts are not limited to these and at least one from the first to the third current spreader 428, 438 and 448 can contact the first to the third transparent electrode 425, 435 and
[0534] [0534] The first to the third current spreader 428, 438 and 448 can be formed of a material with a higher electrical conductivity than the first to the third transparent electrode 425, 435 and 445 and therefore the current can be spread evenly across large regions of the second semiconductor layer of conductivity type 423b, 433b and 443b.
[0535] [0535] The ohmic electrode 446 is in ohmic contact with the first semiconductor layer of conductivity type 443a of the first layer of LED stack 443. The ohmic electrode 446 can be disposed in the first semiconductor layer of conductivity type 443a exposed through the third transparent electrode 445 and in the second semiconductor layer of conductivity type 443b. The ohmic electrode 446 can be formed from Ni / Au / Ti or Ni / Au / Ti / Ni, for example. When a surface of the ohmic electrode 446 is exposed during the etching process, a Ni layer can be formed on the surface of the ohmic electrode 446 to function as an etching stop layer. The ohmic electrode 446 can be formed to have various shapes and, in particular, it can be formed to have substantially an elongated shape to function as a current spreader. In some exemplary embodiments, the ohmic electrode 446 can be omitted.
[0536] [0536] The first color filter 447 can be disposed between the third transparent electrode 445 and the second battery of LED 433 and the second color filter 457 can be disposed between the second battery of LED 433 and the first battery of LED 423. The first 447 color filter transmits light generated from the first and second LED batteries 423 and 433 while reflecting the light generated from the third 443 LED battery. The second 457 color filter transmits light generated from the first LED battery. LED 423 while reflecting the light generated from the second 433 LED battery. Therefore, the light generated from the first 423 LED battery can be emitted out through the second 433 LED battery and the third 443 LED battery, and the light generated from the second LED battery 433 can be emitted out through the third LED battery 443. In addition, it is possible to prevent light loss by preventing the light generated from the second LED battery 433 from entering the first 423 LED stack or the light generated from the third LED stack 443 enter the second LED stack 433.
[0537] [0537] In some exemplary embodiments, the second color filter 457 can reflect the light generated from the third LED stack 443.
[0538] [0538] The first and second color filters 447 and 457 can be, for example, a low pass filter that allows light in a low frequency band, for example, in a long wavelength band to pass through hence, a bandpass filter that allows light in a predetermined wavelength range, or a band interruption filter that prevents light in a predetermined wavelength range from passing through it. In particular, each of the first and second color filters 447 and 457 can be formed by alternately stacking layers of insulation with different refractive indices one above the other, such as TiO2 and SiO2, for example. In particular, each of the first and second color filters 447 and 457 can include a distributed Bragg reflector (DBR). In addition, an interrupted band of the distributed Bragg reflector can be controlled by adjusting the thicknesses of the TiO2 and SiO2 layers. The low-pass filter and the band-pass filter can also be formed by alternately stacking layers of insulation with different refractive indices one above the other.
[0539] [0539] The first link layer 449 couples the second stack of LED 433 to the third stack of LED 443. The first link layer 449 can couple the first color filter 447 to the second transparent electrode 435 between the first color filter 447 and the second transparent electrode 435. For example, the first bonding layer 449 can be formed of a transparent organic material or a transparent inorganic material. Examples of the organic material can include SU8, poly (methyl methacrylate) (PMMA), polyimide, Parylene, benzocyclobutene (BCB) or others, and examples of the inorganic material can include Al2O3, SiO2, SiNx or others. More particularly, the first bonding layer 449 can be formed of spin-on-glass (SOG).
[0540] [0540] The second layer of connection 459 couples the second battery of LED 433 to the first pile of LED 423. As shown in the drawings, the second layer of connection 459 can be arranged between the second color filter 457 and the first transparent electrode 425 The second bonding layer 459 can be formed from substantially the same material as the first bonding layer 449.
[0541] [0541] The holes h1, h2, h3, h4 and h5 are formed through the first substrate 421. The hole h1 can be formed through the first substrate 421, the distributed Bragg reflector 422 and the first LED stack 423 to expose the first transparent electrode 425. Orifice h2 can be formed through the first substrate 421, the distributed Bragg reflector 422, the first transparent electrode 425, the second connection layer 459 and the second color filter 457 to expose the first type semiconductor layer conductivity indicator 433a of the second 433 LED battery
[0542] [0542] Orifice h3 can be formed through the first substrate 421, the distributed Bragg reflector 422, the first transparent electrode 425, the second connection layer 459 and the second color filter 457 and the second LED stack 433 to expose the second transparent electrode 435. Orifice h4 can be formed through the first substrate 421, the distributed Bragg reflector 422, the first transparent electrode 425, the second connection layer 459, the second color filter 457, the second LED stack 433, the second transparent electrode 435, the first connection layer 449 and the first color filter 447 to expose the third transparent electrode 445. In addition, the orifice h5 can be formed through the first substrate 421, the distributed reflector of Bragg 422, the first transparent electrode 425, second connection layer 459, second color filter 457, second LED stack 433, second transparent electrode 435, first connection layer 449 and first f color filter 447 to expose the ohmic electrode 446. When the ohmic electrode 446 is omitted in some exemplary embodiments, the first semiconductor layer of conductivity type 443a can be exposed through the orifice h5.
[0543] [0543] Although the holes h1, h3 and h4 are illustrated as being separated from each other to expose the first to the third transparent electrode 425, 435 and 445, respectively, the inventive concepts are not limited to this and the first to the third transparent electrode 425, 435 and 445 can be exposed through a single hole.
[0544] [0544] In addition, the first to the third transparent electrodes 425, 435 and 445 are illustrated as exposed by the holes h1, h3 and h4, but in some exemplary embodiments, the first to the third current spreaders 428, 438 and 448 can be exposed . The. The bottom insulation layer 461 covers the side surfaces of the first substrate 421 and the first to the third LED stacks 423, 433 and 443 while covering a top surface of the first substrate 421. The bottom insulation layer 461 also covers the side surfaces of the holes h1, h2, h3, h4 and h5. However, the lower insulation layer 461 can be subjected to patterns to expose a bottom of each of the holes h1, h2, h3, h4 and h5. In addition, the lower insulation layer 461 can also be subjected to patterns to expose the upper surface of the first substrate 421.
[0545] [0545] The ohmic electrode 463a is in ohmic contact with the upper surface of the first substrate 421. The ohmic electrode 463a can be formed in an exposed region of the first substrate 421, which is exposed by the pattern of the lower insulation layer 461. The electrode ohmic 463a can be formed from Au-Te alloys or Au-Ge alloys, for example. However, the lower insulation layer 461 can be subjected to patterns to expose a bottom of each of the holes h1, h2, h3, h4 and h5.
[0546] [0546] Through-hole routes 463b, 465a, 465b, 467a and 467b are arranged in holes h1, h2, h3, h4 and h5. Through hole 463b can be arranged in hole h1 and can be connected to the first transparent electrode 425. Through hole 465a can be arranged in hole h2 and be in ohmic contact with the first semiconductor layer of the conductivity type 433a. Through hole 465b can be arranged in hole h3 and can be electrically connected to the second transparent electrode 435. Through hole 467a can be arranged in hole h5 and can be electrically connected to the first semiconductor layer of the conductivity type 443a. For example, through-hole 467a can be electrically connected to ohmic electrode 445 through orifice h5. The through-hole path
[0547] [0547] Through holes 463b, 465a, 465b, 467a and 467b can be separated and insulted from substrate 421 into the holes by the lower insulating layer 461. Through hole 463b, 465a, 465b, 467a and 467b can pass through substrate 421 and can also pass through distributed Bragg reflector 422.
[0548] [0548] At least a portion of each of the heat tubes 469 is disposed within the substrate 421. In particular, the heat tubes 469 can be arranged on the first stack of LED 423 and can be arranged on the distributed Bragg reflector 422 Heat tubes 469 can come in contact with distributed Bragg reflector 422 or can be separated from distributed Bragg reflector 422. Since heat tubes 469 are arranged in distributed Bragg reflector 422, distributed Bragg reflector 422 does not it can be damaged by the 469 heat pipes and, therefore, the reduction of reflectance in the Bragg reflector distributed 422 by the 469 heat pipes can be avoided. In particular, heat tubes 469 can be arranged on the first LED stack 423 and can be arranged on the distributed Bragg reflector 422.
[0549] [0549] As shown in Fig. 52B, heat tubes 469 can be connected to ohmic electrode 463a. However, the inventive concepts are not limited to these and the heat tubes 469 can be separated from the ohmic electrode 463a. In addition, an upper surface of the heat pipes 469 can be substantially aligned with an upper surface of the substrate 421, but in some exemplary embodiments, the upper surface of the heat pipes 469 may protrude above the upper surface of the substrate 421.
[0550] [0550] The upper insulation layer 471 covers the lower insulation layer 461 and the ohmic electrode 463a. The upper insulation layer 471 can cover the lower insulation layer 461 on the sides of the first substrate 421, the first to the third LED stacks 423, 433 and 443. The upper surface of the lower insulation layer 461 can be covered by the insulation layer upper 471. The upper insulating layer 471 may have an opening 471a to expose the ohmic electrode 463a and may have openings to expose the through hole paths 463b, 465a, 465b, 467a and 467b.
[0551] [0551] The upper insulation layer 471 may cover the upper portion of the heat pipes 469, but in some exemplary embodiments, the upper insulation layer 471 may expose the upper surface of the heat pipes 469.
[0552] [0552] The lower insulation layer 461 or the upper insulation layer 471 may be formed without being limited to silicon oxide or silicon nitride. For example, the lower insulation layer 461 or the upper insulation layer 471 can be a distributed Bragg reflector formed by stacking insulation layers with different refractive indices. In particular, the upper insulating layer 471 can be a light reflective layer or a light blocking layer.
[0553] [0553] The electrode pads 473a, 473b, 473c and 473d are arranged in the top insulation layer 471 and are electrically connected to the first to third LED batteries 423, 433 and 443. For example, the first electrode pad 473a is electrically connected to the ohmic electrode 463a exposed through the opening 471a of the upper insulation layer 471, and the second electrode pad 473b is electrically connected to the through hole path 465a exposed through the opening of the upper insulation layer 471. In addition, the third electrode pad 473c is electrically connected to the exposed orifice path 467a exposed through the opening of the upper insulating layer 471. A common electrode pad 473d is electrically connected to pathways 463b, 465b and 467b of the common through hole.
[0554] [0554] Therefore, the common electrode pad 473d is electrically connected to the second semiconductor layers of conductivity type 423b, 433b and 443b from the first to the third LED batteries 423, 433 and 443, and each of the electrode pads 473a , 473b and 473c is electrically connected to the first semiconductor layers of conductivity type 423a, 433a and 443a from the first to the third LED batteries 423, 433 and 443, respectively.
[0555] [0555] According to the exemplary example illustrated, the first LED battery 423 is electrically connected to the electrode pads 473d and 473a, the second LED battery 433 is electrically connected to the electrode pads 473d and 473b and the third LED battery 443 is electrically connected to the electrode pads 473d and 473c. As such, the anodes of the first LED battery 423, the second LED battery 433 and the third LED battery 443 are electrically connected to the electrode pad 473d, and their cathodes are electrically connected to the first to the third electrode pads 473a and 473b and 473c, respectively.
[0556] [0556] Heat tubes 469 can be electrically connected to the first electrode pad 473a through the ohmic electrode 463a. In some exemplary embodiments, a portion of the heat tubes 469 can be arranged in a lower region of the first electrode pad 473a.
[0557] [0557] FIGS. 53A, 53B, 54A, 54B, 55A, 55B, 56, 57, 58, 59A, 59B, 60A, 60B, 61A, 61B, 62A, 62B, 63A, 63B, 64B, 64A, 64B, 65A and 65B are seen flat schematic and cross-sectional views that illustrate a method of manufacturing a light-emitting device for a display, according to an exemplary modality, of the present disclosure. In the drawings, each plan view corresponds to FIG. 52A, and each cross-sectional view is taken along line A-A of the corresponding plan view. FIGS. 53B and 54B are seen in cross section taken along line B-B of FIGS. 53A and 54A, respectively.
[0558] [0558] First, with reference to FIGS. 53A and 53B, a first 423 LED stack is grown on a first substrate
[0559] [0559] A first transparent electrode 425 can be formed in the second semiconductor layer of conductivity type 423b. The first transparent electrode 425 can be formed by a transparent oxide layer, such as tin and indium oxide (ITO), a transparent metal layer or others.
[0560] [0560] The first transparent electrode 425 can be formed to have an opening to expose the second semiconductor layer of conductivity type 423b and a first current spreader 428 can be formed in the opening. The first transparent electrode 425 can be standardized by photolithography and engraving techniques, for example, which can form the opening for the exposure of the second semiconductor layer of conductivity type 423b. The opening of the first transparent electrode 425 can define a region in which the first current spreader 428 can be formed.
[0561] [0561] Although FIG. 53A show the first chain spreader 428 as having substantially a rectangular shape, the inventive concepts are not limited to these. For example, the first chain spreader 428 can take various shapes, such as substantially an elongated or curved line shape. The first current spreader 428 can be formed by the lifting technique or similar, and one side of it can be separated from the first transparent electrode 425. The first current spreader 428 can be formed to have the same thickness or thickness similar to the first electrode transparent 425.
[0562] [0562] Referring to FIGS. 54A and 54B, a second stack of LED 433 is grown on a substrate 431 and a second transparent electrode 435 is formed on the second stack of LED 433. The second stack of LED 433 may include semiconductor layers based on AlGaInP or AlGaInN and may include a first semiconductor layer of conductivity type 433a, an active layer and a second semiconductor layer of conductivity type 433b. Substrate 431 can be a substrate capable of cultivating layers of semiconductors based on AlGaInP, for example, a GaAs substrate or a substrate of GaP, or a substrate capable of cultivating layers of semiconductors based on AlGaInN, for example, a substrate of sapphire. The first type of conductivity can be type n and the second type of conductivity can be type p. A composition ratio of Al, Ga and In for the second LED battery 433 can be determined so that the second LED battery 433 can emit green light, for example. In addition, when the GaP substrate is used, a pure GaP layer or a nitrogen-doped GaP layer (N) is formed in the GaP to emit green light. The second transparent electrode 435 is in ohmic contact with the second semiconductor layer of conductivity type 433b. The second transparent electrode 435 can be formed by a metal layer or a conductive oxide layer, such as SnO2, InO2, ITO, ZnO, IZO and the like.
[0563] [0563] The second transparent electrode 435 can be formed to have an opening to expose the second semiconductor layer of conductivity type 433b and a second current spreader 438 can be formed in the opening. The second transparent electrode 435 can be standardized by photolithography and engraving techniques, for example, which can form the opening for the exposure of the second semiconductor layer of conductivity type 433b. Opening the second transparent electrode 435 can define a region in which the second current spreader 438 can be formed.
[0564] [0564] Although FIG. 54A shows the second chain spreader 438 as having substantially a rectangular shape, the inventive concepts are not limited to this. For example, the second chain spreader 438 can take various shapes, such as substantially an elongated or curved line shape. The second current spreader 438 can be formed by the lifting technique or similar, and one side of it can be separated from the second transparent electrode 435. The second current spreader 438 can be formed to have the same thickness or thickness similar to the second electrode transparent 435.
[0565] [0565] The second chain spreader 438 may have substantially the same shape and size as the first chain spreader 428, but the inventive concepts are not limited to these.
[0566] [0566] Referring to FIGS. 55A and 55B, a third stack of LED 443 is grown on a second substrate 441 and a third transparent electrode 445 is formed on the third stack of LED 443. The third stack of LED 443 can include semiconductor layers based on AlGalnN and can include a first conductivity type semiconductor layer 443a, an active layer and a second conductivity type semiconductor layer 443b. The first type of conductivity can be type n and the second type of conductivity can be type p.
[0567] [0567] The second substrate 441 is a substrate capable of growing GaN-based semiconductor layers, and may be different from the first substrate 421. A composition ratio of AlGaInN to the third LED stack 443 is determined to allow the third 443 LED battery emits blue light, for example. The third transparent electrode 445 is in ohmic contact with the second semiconductor layer of conductivity type 443b. The third transparent electrode 445 can be formed of a layer of conductive oxide, such as SnO2, InO2, ITO, ZnO, IZO and the like.
[0568] [0568] The third transparent electrode 445 can be formed to have an opening to expose the first semiconductor layer of conductivity type 443a and an opening to expose the second semiconductor layer of conductivity type 443b. The opening for exposing the first semiconductor layer of conductivity type 443a can define a region in which an ohmic electrode 446 can be formed and the opening for exposing the second semiconductor layer of conductivity type 443b can define a region for which a third chain spreader 448 can be formed.
[0569] [0569] The third transparent electrode 445 can be standardized by photolithography and engraving techniques, for example, which can form the openings for the exposure of the second semiconductor layer of conductivity type 443b. Thereafter, the first semiconductor layer of conductivity type 443a can be exposed by partial conditioning of the second semiconductor layer of conductivity type 443b, and the ohmic electrode 446 can be formed in an exposed region of the first semiconductor layer of conductivity type 443a. The ohmic electrode 446 can be formed of a metal layer and be in ohmic contact with the first semiconductor layer of conductivity type 443a. For example, the ohmic electrode 446 can be formed from a multilayer structure of Ni / Au / Ti or Ni / Au / Ti / Ni. The ohmic electrode 446 is electrically separated from the third transparent electrode 445 and the second semiconductor layer of conductivity type 443b.
[0570] [0570] The third current spreader 448 is formed in an exposed region of the second semiconductor layer of conductivity type 443b. Although FIG. 55A shows that the third chain spreader 448 is substantially rectangular in shape, the inventive concepts are not limited to this. For example, the third chain spreader 448 can take various shapes, such as substantially an elongated or curved line shape. The third current spreader 448 can be formed by the lifting technique or the like, and one side of it can be separated from the third transparent electrode 445. The third current spreader 448 can be formed to have the same thickness or thickness similar to the third electrode transparent 445.
[0571] [0571] The third chain spreader 448 may have substantially the same shape and size as the first or second chain spreader 428 or 438, but the inventive concepts are not limited to these.
[0572] [0572] Then, a first color filter 447 is formed on the second transparent electrode 445. Since the first color filter 447 is substantially the same as that described with reference to FIG. 52A and FIG. 52B, detailed descriptions will be omitted to avoid redundancy.
[0573] [0573] Referring to FIG. 56, the second LED stack 433 of FIG. 54A and FIG. 54B is connected to the third LED stack 443 of FIG. 55A and FIG. 55B, and the second substrate 431 is removed from it.
[0574] [0574] The first color filter 447 is connected to the second transparent electrode 435 for facing. For example, layers of bonding material can be formed on the first color filter 447 and the second transparent electrode 435 and are bonded together to form a first bonding layer 449. The layers of bonding material can be layers of organic material. transparent or layers of transparent inorganic material, for example. Examples of the organic material can include SU8, poly (methyl methacrylate) (PMMA), polyimide, Parylene, benzocyclobutene (BCB) or others, and examples of the inorganic material can include Al2O3, SiO2, SiNx or others. More particularly, the first bonding layer 449 can be formed of spin-on-glass (SOG).
[0575] [0575] The first type of conductivity can be type n and the second type of conductivity can be type p.
[0576] [0576] Thereafter, substrate 431 can be removed from the second stack of LED 433 by laser lifting or chemical lifting. As such, an upper surface of the first conductivity type semiconductor layer 433a of the second LED stack 433 is exposed. The exposed surface of the first semiconductor layer of conductivity type 433a can be subject to texturing.
[0577] [0577] Referring to FIG. 57, a second color filter 457 is formed on the second LED stack 433. The second color filter 457 can be formed by alternately stacking layers of insulation with different refractive indices and is substantially the same as that described with reference to FIG. 52A and FIG. 52B and therefore its detailed descriptions will be omitted to avoid redundancy.
[0578] [0578] Subsequently, with reference to FIG. 58, the first LED stack 423 of FIGS. 53A and 53B are connected to the second battery of LED 433. The second color filter 457 can be connected to the first transparent electrode 425 to face each other. For example, layers of bonding material can be formed on the second color filter 457 and the first transparent electrode 425 and are bonded together to form a second bonding layer 459. The layers of the bonding material are substantially the same as those described with reference to the first link layer 449 and, therefore, detailed descriptions will be omitted.
[0579] [0579] The first chain spreader 428 may be arranged to overlap the second or third chain spreader 438 or 448, but the inventive concepts are not limited to these.
[0580] [0580] Referring to FIG. 59A and FIG. 59B, the holes h1, h2, h3, h4 and h5 are formed through the first substrate 421 and the insulation trenches that define the regions of the device are formed to expose the first substrate 441.
[0581] [0581] Hole h1 exposes the first transparent electrode 425, hole h2 exposes the first semiconductor layer of conductivity type 433a, hole h3 exposes the second transparent electrode 435, hole h4 exposes the third transparent electrode 445 and hole h5 exposes an ohmic electrode 446. When hole h5 exposes an ohmic electrode 446, an upper surface of the ohmic electrode 446 may include an anti-etching layer, for example, a Ni layer. In an exemplary embodiment, the holes h1, h3 and h4 can expose the first to the third chain spreaders 428, 438 and 448, respectively. In addition, hole h5 can expose the first semiconductor layer of conductivity type 443a.
[0582] [0582] The insulation ditch can expose the second substrate 441 along a periphery of each of the first to the third LED stacks 423, 433 and 443. Although the insulation ditch is illustrated as being formed to expose the second substrate 441 in the illustrated exemplary embodiment, in some exemplary embodiments, the insulation ditch may be formed to expose the first semiconductor layer of conductivity type 443a. The orifice h5 can be formed together with the insulation ditch by the engraving technique or the like, but the inventive concepts are not limited to these.
[0583] [0583] Orifices h1, h2, h3, h4 and h5 and insulation trenches can be formed by photolithography and engraving techniques, and are not limited to a specific training sequence. For example, a shallower orifice may be formed before a deeper orifice, or vice versa. The insulation ditch can be formed before or after the formation of the holes h1, h2, h3, h4 and h5. Alternatively, the insulation ditch can be formed together with the orifice h5, as described above.
[0584] [0584] Referring to FIG. 60A and FIG. 60B, a lower insulation layer 461 is formed on the first substrate 421. The lower insulation layer 461 can cover side surfaces of the first substrate 421 and side surfaces of the first to the third LED stacks 423, 433 and 443, which are exposed through the insulation ditch.
[0585] [0585] The lower insulation layer 461 can also cover the side surfaces of the holes h1, h2, h3, h4 and h5. The lower insulation layer 461 can be patterned to expose a bottom of each of the holes h1, h2, h3, h4 and h5. In addition, the lower insulation layer 461 can be patterned to expose the upper surface of substrate 421. The first substrate 421 can be exposed over a relatively large area, which can exceed more than half the area of the light-emitting device, for example .
[0586] [0586] A process of exposing the bottoms of holes h1, h2, h3, h4 and h5 and a process of exposing the upper surface of substrate 421 can be carried out in the same process or in a separate process.
[0587] [0587] The lower insulation layer 461 may be formed without being limited to silicon oxide or silicon nitride. The insulation layer 461 can include a distributed Bragg reflector.
[0588] [0588] Referring to FIGS. 61A and 61B, the holes h6 are formed in the substrate 421. The holes h6 can be arranged through the substrate 421. The holes h6 can expose a Bragg reflector distributed 422 through the substrate 421, as shown in FIG. 61B, but the inventive concepts are not limited to these. For example, the lower surfaces of the holes h6 formed within the substrate 421, so that the holes h6 can be separated from the distributed Bragg reflector 422 and arranged over the distributed Bragg reflector 422. In another exemplary embodiment, the holes h6 can be extended in the distributed Bragg reflector 422.
[0589] [0589] Referring to FIGS. 62A and 62B, through-hole paths 463b, 465a, 465b, 467a and 467b are formed within holes h1, h2, h2, h3, h4 and h5 and heat pipes 469 are formed within holes h6. Through holes 463b, 465a, 465b, 467a and 467b and heat tubes 469 can be formed by electrical coating or the like. For example, a seed layer can be formed first within holes h1, h2, h3, h4, h5 and h6, and through-hole paths 463b, 465a, 465b, 467a and 467b and heat pipes 469 can be formed by coating with copper using the seed layer. The seed layer can be formed by Ni / Al / Ti / Cu, for example.
[0590] [0590] In the exemplary embodiment illustrated, through-hole paths 463b, 465a, 465b, 467a and 467b are separated from substrate 421 by the lower insulation layer 461. Heat pipes 469, however, may come into contact with substrate 421 within substrate 421. Consequently, heat exchange can occur between heat tubes 469 and substrate 421, so that the heat generated in LED stacks 423, 433 and 443 can be easily spread on substrate 421 and / or abroad.
[0591] [0591] Referring to FIGS. 63A and 63B, an ohmic electrode 463a is formed on the first substrate 421. The ohmic electrode 463a can be formed in an exposed region of the first substrate 421, which is exposed by the pattern of the lower insulation layer 461. The ohmic electrode 463a can be formed as a conductive layer in ohmic contact with the first substrate 421 and can be formed from Au-Te alloys or Au-Ge alloys, for example.
[0592] [0592] As shown in Fig. 63A, the ohmic electrode 463a can be separated from the orifice pathways 463b, 465a, 465b, 467a and 467b and can cover the heat pipes 469. However, the inventive concepts are not limited to these, and the ohmic electrode 463a can be separated from the heat tubes 469.
[0593] [0593] Referring to FIGS. 64A and 64B, an upper insulation layer 471 is formed to cover the lower insulation layer 461 and the ohmic electrode 463a. The upper insulating layer 471 can also cover the lower insulating layer 461 on the side surfaces of the first to third LED stacks 423, 433 and 443 and the first substrate 421. The upper insulating layer 471 can be patterned to form openings that expose the orifice pathways 463b, 465a, 465b, 467a, 467b together with an opening 471a which exposes the ohmic electrode 463a.
[0594] [0594] The upper insulation layer 471 can be formed by a transparent oxide layer, such as silicon oxide or silicon nitride, without being limited to these. For example, the upper insulating layer 471 may be a light reflective insulation layer, for example, a distributed Bragg reflector or a light blocking layer, such as a light absorbing layer.
[0595] [0595] Referring to FIGS. 65A and 65B, the electrode pads 473a, 473b, 473c and 473d are formed in the upper insulating layer 471. The electrode pads 473a, 473b, 473c and 473d can include first to the third electrode pads 473a, 473b and 473c and one common electrode pad 473d.
[0596] [0596] The first electrode pad 473a can be connected to the ohmic electrode 463a exposed through the opening 471a of the upper insulation layer 471, the second electrode pad 473b can be connected to the through hole 465a and the third electrode pad 473c can be connected to through hole 467a. The common electrode pad 473d can be commonly connected to through-hole paths 463b, 465b and 467b.
[0597] [0597] The electrode pads 473a, 473b, 473c and 473d are electrically separated from each other and therefore each from the first to the third LED cells 423, 433 and 443 is electrically connected to two electrode pads to be independently activated .
[0598] [0598] Thereafter, the second substrate 441 is divided into regions for each light emitting device, thus completing the light emitting device 400. As shown in Fig. 65A, the electrode pads 473a, 473b, 473c and 473d can be arranged close to four corners of each light-emitting device 400. In addition, electrodes 473a, 473b, 473c and 473d can be substantially rectangular in shape, but the inventive concepts are not limited to these.
[0599] [0599] Although the second substrate 441 is illustrated as being divided, in some exemplary embodiments, the second substrate 441 can be removed. In this case, an exposed surface of the first semiconductor layer of conductivity type 443 can be subjected to texturing.
[0600] [0600] FIG. 66A and FIG. 66B are a schematic plan view and a cross-sectional view of a light-emitting device 402 for a display, according to another exemplary embodiment.
[0601] [0601] Referring to FIGS. 66A and 66B, the light-emitting device 402 according to the exemplary embodiment illustrated is substantially similar to the light-emitting device 400 described with reference to FIG. 52A and FIG. 52B, except that the anodes of the first to the third LED batteries 423, 433 and 443 are independently connected to the first to the third electrode pads 4173a, 4173b, 4173c, and their cathodes are electrically connected to a common electrode pad 4173d.
[0602] [0602] In particular, the first electrode pad 4173a is electrically connected to the first transparent electrode 425 through a through-hole path 4163b, the second electrode pad 4173b is electrically connected to the second transparent electrode 435 through an orifice path passthrough 4165b and the third electrode pad 4173c is electrically connected to the third transparent electrode 445 through a passage orifice path 4167b. The common electrode pad 4173d is electrically connected to an ohmic electrode 4163a exposed through opening 471a of the upper insulating layer 471 and is also electrically connected to the first semiconductor layers of conductivity type 433a and 443a of the second LED stack 433 and the third 445 LED stack through the through hole paths 4165a, 4167a. For example, the 4165a through-hole path can be connected to the first conductivity type 433a semiconductor layer, and the 4167a through-hole path can be connected to the ohmic electrode 446 in ohmic contact with the first semiconductor layer. conductivity type 443a.
[0603] [0603] The 4169 heat pipes are arranged as described with reference to FIGS. 52A and 52B. However, in the exemplary embodiment illustrated, the heat tubes 4169 are connected to the ohmic electrode 4163a and therefore can be electrically connected to the common electrode pad 4173d.
[0604] [0604] FIG. 67A and FIG. 67B are a schematic plan view and a cross-sectional view of a 403 light-emitting device for a display, according to another exemplary embodiment, respectively.
[0605] [0605] Referring to FIGS. 67A and 67B, the light-emitting device 403 according to the exemplary embodiment illustrated is substantially similar to the light-emitting device 400 described with reference to FIGS. 52A and 52B, except that heat pipes 4269 are isolated from substrate 421 by the lower insulation layer 461.
[0606] [0606] More particularly, the lower insulation layer 461 covers the side walls of the through holes h1, h2, h3, h4 and h5 and further covers the side walls of the holes h6 where the heat pipes 4269 are formed. The lower insulation layer 461 can also cover the bottoms of the h6 holes.
[0607] [0607] In addition, heat tubes 4269 can be separated from the ohmic electrode 463a. Therefore, heat pipes 4269 can be electrically isolated from substrate 421. However, the inventive concepts are not limited to these, and ohmic electrode 463a can cover heat pipes 4269 and be connected to heat pipes 4269.
[0608] [0608] Referring back to FIGS. 60A to 60B, holes h6 were formed after the formation of the lower insulation layer 461 in the light-emitting device 400. However, according to the exemplary embodiment illustrated, since the heat pipes 4269 are separated from the substrate 421 by lower insulation layer 461 inside holes h6, the lower insulation layer 461 is also formed inside holes h6. Therefore, the bottom insulation layer 461 can be formed after through holes h1, h2, h3, h4 and h5 and holes h6 are formed. For example, after the through holes h1, h2, h3, h4 and h5 and the holes h6 are formed, the side walls of the through holes h1, h2, h3, h4 and h5 and the holes h6 are covered with the layer lower insulation layer 461. Therefore, when standardizing the lower insulation layer 461 inside the through holes h1, h2, h3, h4 and h5 to form an opening, the lower insulation layer 461 formed at the bottom of the holes h6 cannot be patterned covering the h6 holes with a mask, for example.
[0609] [0609] FIG. 68A and FIG. 68B are a schematic plan view and a cross-sectional view of a light-emitting device 404 for a display, according to another exemplary embodiment.
[0610] [0610] Referring to FIGS. 68A and 68B, the light-emitting device 404 according to the exemplary embodiment illustrated is substantially similar to the light-emitting device 403 described with reference to FIGS. 67A and 67B, except that the 4369 heat pipes are still arranged under the electrode pads 4173a, 4173b, 4173c and 4173d.
[0611] [0611] The 4369 heat tubes can be connected to the electrode pads 4173a, 4173b, 4173c and 4173d and therefore heat can be quickly discharged to the outside of the 404 light emitting device through the 4369 heat tubes and the electrode pads 4173a, 4173b, 4173c and 4173d.
[0612] [0612] Each of the light-emitting devices 400, 402, 403 and 404 according to the exemplary modalities includes the first to third LED batteries 423, 433 and 443, which emit red, green and blue light, respectively, and, therefore, it can be used as a pixel on a display device. As shown in Fig. 51, the display device can be realized by arranging a plurality of light emitting devices 400, 402, 403 or 404 on circuit board 401. Like each of the light emitting devices 400, 402, 403 and 404 includes the first to third batteries of LED 423, 433 and 443, it is possible to increase the area of a subpixel by one pixel. In addition, the first to third LED batteries 423, 433 and 443 can be mounted on the circuit board by mounting a light-emitting device, thereby reducing the number of assembly processes.
[0613] [0613] As described in FIG. 51, the light-emitting devices mounted on the circuit board 401 can be activated passively by matrix or by active matrix.
[0614] [0614] FIG. 69 is a schematic plan view of a display device according to an exemplary embodiment.
[0615] [0615] Referring to FIG. 69, the display device, according to an exemplary embodiment, includes a circuit board 501 and a plurality of light-emitting devices
[0616] [0616] Circuit board 501 may include a circuit for passively driving the matrix or active driving the matrix. In an exemplary embodiment, circuit board 501 can include interconnect lines and resistors. In another exemplary embodiment, circuit board 501 can include interconnect lines, transistors and capacitors. Circuit board 501 may also have electrode pads arranged on an upper surface of the board to allow electrical connection to the circuit on it.
[0617] [0617] The light-emitting devices 500 are arranged on the circuit board 501. Each of the light-emitting devices 500 can constitute a pixel. The light-emitting device 500 includes electrode pads 573a, 573b, 573c, 573d, which are electrically connected to the circuit board 501. In addition, the light-emitting device 500 may include a substrate 541 on an upper surface thereof. Since the light emitting devices 500 are separated from each other, the substrates 541 arranged on the upper surfaces of the light emitting devices 500 are also separated from each other.
[0618] [0618] Details of the light emitting device 500 will be described with reference to FIG. 70A and FIG. 70B. FIG. 70A is a schematic plan view of a light emitting device 500 for a display, according to an exemplary embodiment, and FIG. 70B is a schematic cross-sectional view along a line A-A of FIG. 70A. Although the 573a electrode pads,
[0619] [0619] Referring to FIG. 70A and FIG. 70B, the light-emitting device 500 may include a first substrate 521, a second substrate 541, a distributed Bragg reflector 522, a first LED stack 523, a second LED stack 533, a third LED stack 543, a first electrode ohmic 525, a second ohmic electrode 535, a third ohmic electrode 545, an ohmic electrode 546, a first color filter 547, a second color filter 557, a first connection layer 549, a second connection layer 559, a second layer lower insulation layer 561, an upper insulation layer 571, an ohmic electrode 563a, orifice paths 563b, 565a, 565b, 567a and 567b and electrode pads 573a, 573b, 573c, 573d.
[0620] [0620] The first substrate 521 can support the LED cells 523, 533 and 543. The first substrate 521 can be a growth substrate for the growth of the first LED stack 523, for example, a GaAs substrate. In particular, the first substrate 521 can have conductivity.
[0621] [0621] The second substrate 541 can support the LED cells 523, 533 and 543. The LED cells 523, 533 and 543 are arranged between the first substrate 521 and the second substrate
[0622] [0622] In another exemplary embodiment, a plurality of third LED batteries 543 can be arranged on a single second substrate 541. The second LED stack 533, the first LED stack 523 and the first substrate 521 can be arranged on each one of the third LED batteries 543, whereby the light emitting device 500 has a single chip structure of a plurality of pixels.
[0623] [0623] In some exemplary embodiments, the second substrate 541 can be omitted and a lower surface of the third LED stack 543 can be exposed. In this case, a rough surface can be formed on the bottom surface of the third LED stack 543 by surface textures.
[0624] [0624] Each of the first LED stack 523, the second LED stack 533 and the third LED stack 543 includes a first layer of conductivity type semiconductors 523a, 533a and 543a, a second layer of conductivity type semiconductor 523b, 533b and 543b and an active layer of conductivity type semiconductors layer interposed between them. The active layer can have a multi-quantum well structure.
[0625] [0625] The LED cells can emit light with a shorter wavelength, being placed closer to the second substrate 541. For example, the first LED battery 523 can be an inorganic light emitting diode adapted to emit red light, the second 533 LED stack can be an inorganic light emitting diode adapted to emit green light, and the third 543 LED stack can be an inorganic light emitting diode adapted to emit blue light. The first LED stack 523 can include a well layer based on AlGaInP, the second LED stack 533 can include a well layer based on AlGaInP or AlGaInN and the third LED stack 543 can include a well layer based on AlGaInN. However, inventive concepts are not limited to these. When the light-emitting device 500 includes a micro LED, which has a surface area of less than about 10,000 µm squared, as known in the art, or less than about 4,000 µm squared or 2,500 µm squared in other exemplary modalities, the first LED battery 523 can emit any red, green and blue light, and the second and third LED batteries 533 and 543 can emit a light other than red, green and blue, without adversely affecting the operation, due to the small form factor of a micro LED.
[0626] [0626] The first semiconductor layer of conductivity type 523a, 533a and 543a of each of the LED cells 523, 533 and 543 can be a semiconductor type n and the second semiconductor layer of conductivity type 523b, 533b and 543b can be a p-type semiconductor layer. In the illustrated exemplary embodiment, an upper surface of the first LED battery 523 is a semiconductor layer of type n 523a, an upper surface of the second LED pile 533 is a semiconductor layer of type n 533a and an upper surface of the third LED battery 543 it is a semiconductor layer of type p 543b. More particularly, only the semiconductor layers of the third LED stack 543 are stacked in a different sequence than that of the first and second LED cells 523 and 533. The first semiconductor layer of conductivity type 543a of the third LED stack 543 can be subjected to surface textures in order to improve the efficiency of light extraction. In some exemplary embodiments, the first conductivity type semiconductor layer 533a of the second LED stack 533 may also be subject to surface texturing.
[0627] [0627] The first LED battery 523, the second LED battery 533 and the third LED battery 543 can be stacked to overlap and can have substantially the same light area. In addition, in each of the LED cells 523, 533 and 543, the first conductivity type semiconductor layer 523a, 533a and 543a can have substantially the same area as the second conductivity type semiconductor layer 523b, 533b and 543b. In particular, in each of the first LED stack 523 and the second LED stack 533, the first semiconductor layer of conductivity type 523a or 533a can completely overlap the second semiconductor layer of conductivity type 523b and 533b. In the third LED stack 543, an orifice h5 is formed in the second semiconductor layer of conductivity type 543b to expose the first semiconductor layer of conductivity type 543a and therefore the first semiconductor layer of conductivity type 543a has a slightly area greater than the second semiconductor layer of conductivity type 543b.
[0628] [0628] The first battery of LED 523 is disposed in addition to the second substrate 541, the second battery of LED 533 is disposed under the first battery of LED 523 and the third battery of LED 543 is disposed under the second battery of LED 533. One Since the first LED battery 523 can emit light with a longer wavelength than the second and third LED batteries 533 and 543, the light generated from the first LED battery 523 can be emitted outside after passing through the second and third batteries of LED 533 and 543 and second substrate 541. In addition, since the second battery of LED 533 can emit light with a longer wavelength than the third battery of LED 543, the light generated from the second battery of LED 533 can be emitted outside after passing through the third LED stack 543 and the second substrate 541.
[0629] [0629] The distributed Bragg reflector 522 can be disposed between the first substrate 521 and the first LED stack 523. The distributed Bragg reflector 522 reflects the light generated from the first LED stack 523 to prevent light from being lost through absorption by the substrate 521. For example, the distributed Bragg reflector 522 can be formed by alternately stacking the semiconductor layers based on AlAs and AlGaAs one above the other.
[0630] [0630] The first ohmic electrode 525 is disposed between the first battery of LED 523 and the second battery of LED 533. The first ohmic electrode 525 is in ohmic contact with the second semiconductor layer of conductivity type 523b of the first LED battery. 523 and transmits light generated from the first LED battery 523. The first ohmic electrode 525 can be formed as a mesh electrode. For example, the first ohmic electrode 525 may include the mesh electrode formed by an Au-Zn or Au-Be metal layer. As shown in Fig. 71B, the first ohmic electrode 525 can include a pad region 525a and the through hole path 563b can be connected to the pad region 525a.
[0631] [0631] As used in this document, the term "mesh electrode" can refer to a conductor or conductive structure with a mesh shape, which can be formed in lines connected to each other and openings surrounded by the lines. In some exemplary embodiments, the lines connected to each other can be straight or curved lines, without being limited to them. In addition, the lines can be the same or different in thickness, and the openings surrounded by the lines can have areas that are the same or different from each other. The mesh electrode can generally form a regular pattern in a plan view, but in some exemplary embodiments, the pattern formed by the mesh electrode can be irregular. The first ohmic electrode 525 may have openings, through which the orifice pathways 565a, 565b, 567a and 567b pass without coming into contact with the first ohmic electrode 525.
[0632] [0632] The second ohmic electrode 535 is in ohmic contact with the second semiconductor layer of conductivity type 533b of the second 533 LED cell. As shown in the drawings, the second ohmic electrode 535 comes in contact with a lower surface of the second battery of 533b. LED 533 between the second battery 533 LED and the third battery LED 543. The second ohmic electrode 535 can be formed as the mesh electrode. For example, the second ohmic electrode 535 may include the mesh electrode including Pt or Rh and may have a multilayer structure of Ni / Ag / Pt, for example. The second ohmic electrode 535 may include a pad region (see 535a of FIG. 72A) for connecting through hole port 565b.
[0633] [0633] The third ohmic electrode 545 is in ohmic contact with the second semiconductor layer of conductivity type 543b of the third LED battery 543. The third ohmic electrode 545 can be arranged between the second LED battery 533 and the third LED battery 543 and comes in contact with the upper surface of the third 543 LED battery. In an exemplary embodiment, the third ohmic electrode 545 can be formed from a metal layer or a conductive oxide layer, such as ZnO, which is transparent to light red and green light. The third ohmic electrode 545 can also be transparent to blue light. In another exemplary embodiment, the third ohmic electrode 545 can be formed as a mesh electrode. For example, the third ohmic electrode 545 may include the mesh electrode including Pt or Rh and may have, for example, a multilayer structure of Ni / Ag / Pt. The third ohmic electrode 545 may include a pad region (see 545a of FIG. 73A) for connecting through hole port 567b.
[0634] [0634] Each of the first ohmic electrode 525, the second ohmic electrode 535 and the third ohmic electrode 545 are in ohmic contact with the p-type semiconductor layer of each of the LED cells to aid in current propagation. In addition, the mesh electrode includes the openings for transmitting light generated from the first to the third LED batteries 523, 533 and 543.
[0635] [0635] The first color filter 547 can be disposed between the third ohmic electrode 545 and the second battery of LED 533 and the second color filter 557 can be disposed between the second battery of LED 533 and the first battery of LED 523. The first color filter 547 transmits light generated from the first and second batteries of LEDs 523 and 533, while reflecting the light generated from the third battery of LED 543. The second color filter 557 transmits light generated from the first battery 523 LED while reflecting the light generated from the second LED stack
[0636] [0636] In some exemplary embodiments, the second color filter 557 can reflect the light generated from the third LED stack 543.
[0637] [0637] The first and second color filters 547 and 557 can be, for example, a low pass filter that allows light in a low frequency band, for example, a long wavelength band, to pass through it , a bandpass filter that allows light in a predetermined wavelength range, or a bandpass filter that prevents light in a predetermined wavelength range from passing through it. In particular, each of the first and second color filters 547 and 557 can be formed by alternately stacking layers of insulation with different refractive indices one above the other, such as TiO2 and SiO2, for example. In particular, each of the first and second color filters 547 and 557 can include a distributed Bragg reflector (DBR). In addition, an interrupted band of the distributed Bragg reflector can be controlled by adjusting the thicknesses of the TiO2 and SiO2 layers. The low-pass filter and the band-pass filter can also be formed by alternately stacking layers of insulation with different refractive indices one above the other.
[0638] [0638] The first connection layer 549 couples the second battery of LED 533 to the third pile of LED 543. The first connection layer 549 can couple the first color filter 547 to the second ohmic electrode 535 between the first color filter 547 and the second ohmic electrode 535. For example, the first bonding layer 549 can be formed of a transparent organic material or a transparent inorganic material. Examples of the organic material can include SU8, poly (methyl methacrylate) (PMMA), polyimide, Parylene, benzocyclobutene (BCB) or others, and examples of the inorganic material can include Al2O3, SiO2, SiNx or others. More particularly, the first connection layer 549 can be formed from spin-on-glass (SOG).
[0639] [0639] The second connection layer 559 couples the second battery of LED 533 to the first battery of LED 523. As shown in the drawings, the second connection layer 559 can be arranged between the second color filter 557 and the first ohmic electrode.
[0640] [0640] Orifices h1, h2, h3, h4 and h5 are formed through the first substrate 521. Orifice h1 can be formed through the first substrate 521, the distributed Bragg reflector 522 and the first LED stack 523 to expose the first ohmic electrode 525. For example, hole h1 can expose the pad region 525a. The orifice h2 can be formed through the first substrate 521, the distributed Bragg reflector 522, the first ohmic electrode 525, the second connection layer 559 and the second color filter 557 to expose the first conductivity type semiconductor layer 533a of the second pile of
[0641] [0641] Orifice h3 can be formed through the first substrate 521, the distributed Bragg reflector 522, the first ohmic electrode 525, the second connection layer 559, the second color filter 557 and the second stack of LED 533 to expose the second ohmic electrode 535. For example, hole h3 can expose the pad region 535a. The orifice h4 can be formed through the first substrate 521, the distributed Bragg reflector 522, the first ohmic electrode 525, the second connection layer 559, the second color filter 557, the second LED stack 533, the second ohmic electrode 535 , the first connection layer 549 and the first color filter 547 to expose the third ohmic electrode 545. For example, hole h4 can expose the pad region 545a. In addition, orifice h5 can be formed through the first substrate 521, the distributed Bragg reflector 522, the first ohmic electrode 525, the second connection layer 559, the second color filter 557, the second LED stack 533, the second ohmic electrode 535, the first link layer 549 and the first color filter 547 to expose the ohmic electrode 546. When the ohmic electrode 546 is omitted in some exemplary embodiments, the first semiconductor layer of conductivity type 543a can be exposed through the hole h5.
[0642] [0642] Although the holes h1, h3 and h4 are illustrated as being separated from each other to expose the first to the third ohmic electrode 525, 535 and 545, respectively, however, the inventive concepts are not limited to these and the first to the third ohmic electrodes 525, 535 and 545 can be exposed through a single hole.
[0643] [0643] The bottom insulation layer 561 covers the side surfaces of the first substrate 521 and the first to the third LED stacks 523, 533 and 543, while covering an upper surface of the first substrate 521. The bottom insulation layer 561 also covers the side surfaces of holes h1, h2, h3, h4 and h5. The lower insulation layer 561 can be subjected to patterns to expose a bottom of each of the holes h1, h2, h3, h4 and h5. In addition, the lower insulation layer 561 can also be subjected to patterns to expose the upper surface of the first substrate 521.
[0644] [0644] The ohmic electrode 563a is in ohmic contact with the upper surface of the first substrate 521. The ohmic electrode 563a can be formed in an exposed region of the first substrate 521, which is exposed by the pattern of the lower insulation layer 561. The electrode ohmic 563a can be formed from Au-Te alloys or Au-Ge alloys, for example.
[0645] [0645] The through hole routes 563b, 565a, 565b, 567a and 567b are arranged in holes h1, h2, h3, h4 and h5. Through hole 563b can be arranged in hole h1 and can be electrically connected to the first ohmic electrode 525. Through hole 565a can be arranged in hole h2 and be in ohmic contact with the first semiconductor layer of the type conductivity 533a. Through hole 565b can be arranged in hole h3 and can be electrically connected to the second ohmic electrode 535. Through hole 567a can be arranged in hole h5 and can be electrically connected to the first semiconductor layer of the conductivity type 543a. For example, through-hole path 567a can be electrically connected to ohmic electrode 546 through hole h5. Through hole 567b can be arranged in hole h4 and can be connected to third ohmic electrode 545. Through hole ways
[0646] [0646] The upper insulation layer 571 covers the lower insulation layer 561 and covers the ohmic electrode 563a. The upper insulation layer 571 can cover the lower insulation layer 561 on the side surfaces of the first substrate 521 and the first to the third LED stacks 523, 533 and 543, and can cover the lower insulation layer 561 on the first substrate 521. The upper insulating layer 571 can have an opening 571a exposing the ohmic electrode 563a and can also have openings exposing the pathways 563b, 565a, 565b, 567a and 567b.
[0647] [0647] The lower insulation layer 561 or the upper insulation layer 571 may be formed of silicon oxide or silicon nitride, but is not limited to these. For example, the bottom insulation layer 561 or the top insulation layer 571 can be a distributed Bragg reflector formed by stacking insulation layers with different refractive indices. In particular, the upper insulating layer 571 can be a light reflective layer or a light blocking layer.
[0648] [0648] The electrode pads 573a, 573b, 573c and 573d are arranged in the upper insulation layer 571 and are electrically connected to the first to the third LED batteries 523, 533 and 543. For example, the first electrode pad 573a is electrically connected to the ohmic electrode 563a exposed through the opening 571a of the upper insulation layer 571, and the second electrode pad 573b is electrically connected to the through-hole path 565a exposed through the opening of the upper insulation layer 571. The third electrode pad 573c is electrically connected to the through hole port 567a exposed through the opening of the upper insulating layer 571. A common electrode pad 573d is commonly electrically connected to the through hole ways 563b, 565b and 567b.
[0649] [0649] Consequently, the common electrode pad 573d is normally electrically connected to the second semiconductor layers of conductivity type 523b, 533b and 543b from the first to the third LED batteries 523, 533 and 543, and each of the electrode pads 573a, 573b, 573c is electrically connected to the first semiconductor layers of conductivity type 523a, 533a and 543a from the first to the third LED batteries 523, 533 and 543, respectively.
[0650] [0650] According to an exemplary embodiment, the first LED battery 523 is electrically connected to the electrode pads 573d and 573a, the second LED battery 533 is electrically connected to the electrode pads 573d and 573b and the third LED battery 543 is electrically connected to the 573d and 573c electrode pads. As such, the anodes of the first LED battery 523, the second LED battery 533 and the third LED battery 543 are commonly electrically connected to the electrode pad 573d, and their cathodes are electrically connected to the first to the third electrode pads 573a , 573b and 573c, respectively. Therefore, the first to the third LED batteries 523, 533 and 543 can be driven independently.
[0651] [0651] FIGS. 71A, 71B, 72A, 72B, 73A, 73B, 74, 75, 76, 77A, 77B, 78A, 78B, 79A, 47A, 79B, 80A, 80B, 81A and 81B are schematic plan views and cross-sectional views illustrating a method of making a light-emitting device for a screen according to an exemplary embodiment. In the drawings, each plan view corresponds to FIG. 70A, and each cross-sectional view is taken along line A-A of the corresponding plan view. FIGS. 71B and 72B are seen in cross section taken along line B-B of FIGS. 71A and 72A, respectively.
[0652] [0652] First, with reference to FIGS. 71A and 71B, a first 523 LED stack is grown on a first substrate
[0653] [0653] A first ohmic electrode 525 can be formed in the second semiconductor layer of conductivity type 523b. The first ohmic electrode 525 can be formed from a layer of ohmic metal, such as Au-Zn or Au-Be, using the E-beam Evaporation technique, for example. The ohmic metal layer can be standardized by photolithography and engraving techniques to be formed as the mesh electrode with openings, as shown in FIG. 71A. In addition, the first ohmic electrode 525 can be formed to have a pad region 525a.
[0654] [0654] Referring to FIGS. 72A and 72B, a second stack of LED 533 is grown on a substrate 531 and a second ohmic electrode 535 is formed on the second stack of LED 533. The second stack of LED 533 may include semiconductor layers based on AlGaInP or AlGaInN and may include a first semiconductor layer of conductivity type 533a, an active layer and a second semiconductor layer of conductivity type 533b. Substrate 531 can be a substrate capable of cultivating layers of semiconductors based on AlGaInP, for example, a GaAs substrate or a substrate of GaP, or a substrate capable of cultivating layers of semiconductors based on AlGaInN, for example, a substrate of sapphire. The first type of conductivity can be type n and the second type of conductivity can be type p. A composition ratio of Al, Ga and In for the second LED 533 battery can be determined so that the second LED 533 battery can emit green light, for example. In addition, when the GaP substrate is used, a pure GaP layer or a nitrogen (N) doped GaP layer is formed in the GaP to generate green light. The second ohmic electrode 535 is in ohmic contact with the second semiconductor layer of conductivity type 533b. For example, the second ohmic electrode 535 can include Pt or Rh and can, for example, be formed of Ni / Ag / Pt. The second ohmic electrode 535 can also be formed as a mesh electrode by photolithography and engraving techniques, and can include a 535a pad region.
[0655] [0655] Referring to FIG. 73A and FIG. 73B, a third LED stack 543 is grown on a second substrate 541 and a third ohmic electrode 545 is formed on the third LED stack
[0656] [0656] The second substrate 541 is a substrate capable of growing GaN-based semiconductor layers, and may be different from the first substrate 521. A composition ratio of AlGaInN to the third LED stack 543 is determined to allow the third 543 LED battery emits blue light, for example. The third ohmic electrode 545 is in ohmic contact with the second semiconductor layer of conductivity type 543b. The third ohmic electrode 545 can be formed from a conductive oxide layer, such as SnO2, ZnO, IZO or others. Alternatively, the third ohmic electrode 545 can be formed as a mesh electrode. For example, the third ohmic electrode 545 can be formed as the mesh electrode including Pt or Rh and can have,
[0657] [0657] After the openings are formed to expose the second semiconductor layer of conductivity type 543b, standardizing the third ohmic electrode 545, the first semiconductor layer of conductivity type 543a can be exposed by partially etching the second semiconductor layer of conductivity type 543b . Thereafter, an ohmic electrode 546 can be formed in an exposed region of the first semiconductor layer of conductivity type 543a. The ohmic electrode 546 can be formed from a metal layer in ohmic contact with the first semiconductor layer of conductivity type 543a. For example, the ohmic electrode 546 may have a multilayer structure of Ni / Au / Ti or Ni / Au / Ti / Ni. However, the ohmic electrode 546 is electrically separated from the third ohmic electrode 545 and the second semiconductor layer of conductivity type 543b.
[0658] [0658] In some exemplary embodiments, a current spreader can be formed together with the third ohmic electrode 545 to improve current spreading performance. More particularly, when the third ohmic electrode 545 is formed from a conductive oxide layer, the conductive oxide layer is etched to partially expose the second semiconductor layer of conductivity type 543b, and the current spreader can be additionally formed as a layer of metal with high electrical conductivity in an exposed region of the second semiconductor layer of conductivity type 543b.
[0659] [0659] Then, a first color filter 547 is formed on the second ohmic electrode 545. Since the first color filter 547 is substantially the same as that described with reference to FIG. 70A and FIG. 70B, detailed descriptions of it will be omitted.
[0660] [0660] Referring to FIG. 74, the second LED stack 533 of FIG. 72A and FIG. 72B is connected to the third LED stack 543 of FIG. 73A and FIG. 73B, and the second substrate 531 is removed therefrom.
[0661] [0661] The first color filter 547 is connected to the second ohmic electrode 535 to face the other. For example, layers of bonding material can be formed on the first color filter 547 and the second ohmic electrode 535, and are bonded together to form a first bonding layer 549. The layers of bonding material can be layers of material transparent organic or layers of transparent inorganic material, for example. Examples of the organic material can include SU8, poly (methyl methacrylate) (PMMA), polyimide, Parylene, benzocyclobutene (BCB) or others, and examples of the inorganic material can include Al2O3, SiO2, SiNx or others. More particularly, the first connection layer 549 can be formed from spin-on-glass (SOG).
[0662] [0662] Thereafter, substrate 531 can be removed from the second stack of LED 533 by laser lifting or chemical lifting. As such, an upper surface of the first conductivity type semiconductor layer 533a of the second LED stack 533 is exposed. In an exemplary embodiment, the exposed surface of the first semiconductor layer of conductivity type 533a can be subjected to texturing.
[0663] [0663] Referring to FIG. 75, a second color filter 557 is formed on the second LED stack 533. The second color filter 557 can be formed by alternately stacking layers of insulation with different refractive indices and is substantially the same as that described with reference to FIG. 70A and FIG. 70B and therefore its detailed descriptions will be omitted to avoid repetition.
[0664] [0664] Subsequently, with reference to FIG. 76, the first LED stack 523 of FIG. 71 is connected to the second LED battery 533. The second color filter 557 can be connected to the first ohmic electrode 525 to face the other. For example, layers of bonding material can be formed on the second color filter 557 and the first ohmic electrode 525 and are bonded together to form a second bonding layer 559. The layers of the bonding material are substantially the same as the described with reference to the first link layer 549 and, therefore, detailed descriptions will be omitted.
[0665] [0665] Referring to FIG. 77A and FIG. 77B, the holes h1, h2, h3, h4 and h5 are formed through the first substrate 521 and the insulation trenches that define the regions of the device are also formed to expose the first substrate 541.
[0666] [0666] Hole h1 can expose the pad region 525a of the first ohmic electrode 525, hole h2 can expose the first semiconductor layer of conductivity type 533a, hole h3 can expose the pad region 535a of the second ohmic electrode 535, hole h4 can expose pad region 545a of third ohmic electrode 545 and hole h5 can expose ohmic electrode 546. When hole h5 exposes ohmic electrode 546, an upper surface of ohmic electrode 546 can include an anti-etching layer , for example, a layer of Ni.
[0667] [0667] The insulation ditch can expose the second substrate
[0668] [0668] Orifices h1, h2, h3, h4 and h5 and insulation trenches can be formed by photolithography and engraving techniques, and are not limited to a specific training sequence. For example, a shallower orifice may be formed before a deeper orifice, or vice versa. The insulation ditch can be formed before or after the formation of the holes h1, h2, h3, h4 and h5. Alternatively, the insulation ditch can be formed together with the orifice h5, as described above.
[0669] [0669] Referring to FIG. 78A and FIG. 78B, a lower insulation layer 561 is formed on the first substrate 521. The lower insulation layer 561 can cover side surfaces of the first substrate 521 and side surfaces of the first to the third LED stacks 523, 533 and 543, which are exposed through the insulation ditch.
[0670] [0670] The bottom insulation layer 561 can also cover the side surfaces of the holes h1, h2, h3, h4 and h5. The lower insulation layer 561 is subjected to standardization to expose a bottom of each of the holes h1, h2, h3, h4 and h5.
[0671] [0671] The bottom insulation layer 561 may be formed from silicon oxide or silicon nitride, but is not limited to these. The insulation layer 561 can include a distributed Bragg reflector.
[0672] [0672] Subsequently, through-hole routes 563b, 565a, 565b, 567a and 567b are formed in holes h1, h2, h3, h4 and h5. Through holes 563b, 565a, 565b, 567a and 567b can be formed by electrical plating or the like. For example, a seed layer can be formed first within holes h1, h2, h3, h4 and h5 and through-hole paths 563b, 565a, 565b, 567a and 567b can be formed by coating with copper using the seed. The seed layer can be formed by Ni / Al / Ti / Cu, for example. Through holes 563b, 565b and 567b can be connected to pad regions 525a, 535a and 545a, respectively, and through holes 565a and 567a can be connected to the first conductivity type semiconductor layer 533a and to the ohmic electrode 546, respectively.
[0673] [0673] Referring to FIG. 79A and FIG. 79B, the upper surface of the first substrate 521 can be exposed by modeling the lower insulation layer 561. The process of standardizing the lower insulation layer 361 to expose the upper surface of the first substrate 321 can be carried out after standardizing the lower insulation layer 361 to expose the bottoms of holes h1, h2, h3, h4, h5.
[0674] [0674] The upper surface of the first substrate 521 can be exposed over a wide area and can exceed, for example, half the area of the light emitting device.
[0675] [0675] Thereafter, an ohmic electrode 563a is formed on the exposed upper surface of the first substrate 521. The ohmic electrode 563a can be formed of a conductive layer and in ohmic contact with the first substrate 521. The ohmic electrode 563a can include Au alloys -Te or Au-Ge alloys, for example.
[0676] [0676] As shown in Fig. 79A, the ohmic electrode 563a is separated from the orifice pathways 563b, 565a, 565b, 567a and 567b.
[0677] [0677] Referring to FIG. 80A and FIG. 80B, an upper insulation layer 571 is formed to cover the lower insulation layer 561 and the ohmic electrode 563a. The top insulation layer 571 can also cover the bottom insulation layer 561 on the side surfaces of the first to third LED stacks 523, 533 and 543 and on the first substrate
[0678] [0678] The upper insulating layer 571 may be formed by a transparent oxide layer, such as silicon oxide or silicon nitride, but is not limited to these. For example, the upper insulating layer 571 may be a light reflective insulation layer, for example, a distributed Bragg reflector or a light blocking layer, such as a light absorbing layer.
[0679] [0679] Referring to FIG. 81A and FIG. 81B, electrode pads 573a, 573b, 573c and 573d are formed in the upper insulating layer 571. Electrode pads 573a, 573b, 573c and 573d can include first to third electrode pads 573a, 573b and 573c and a pad of common 573d electrode.
[0680] [0680] The first electrode pad 573a can be connected to the ohmic electrode 563a exposed through the opening 571a of the upper insulation layer 571, the second electrode pad 573b can be connected to the through hole path 565a and the third electrode pad 573c can be connected to through-hole path 567a. The common electrode pad 573d can be commonly connected to through-hole pathways 563b, 565b and 567b.
[0681] [0681] The electrode pads 573a, 573b, 573c and 573d are electrically separated from each other and therefore each of the first to the third LED batteries 523, 533 and 543 is electrically connected to two electrode pads to be independently activated .
[0682] [0682] Thereafter, the second substrate 541 is divided into regions for each light emitting device, thus completing the light emitting device 500. As shown in Fig. 81A, the electrode pads 573a, 573b, 573c and 573d can be arranged around four corners of each light emitting device 500. In addition, electrodes 573a, 573b, 573c and 573d can be substantially rectangular in shape, but the inventive concepts are not limited to these.
[0683] [0683] Although the second substrate 541 is illustrated as being divided, in some exemplary embodiments, the second substrate 541 can be removed. In this case, an exposed surface of the first semiconductor layer of conductivity type 43 can be subjected to texturing.
[0684] [0684] FIG. 82A and FIG. 82B are a schematic plan view and a cross-sectional view of a light-emitting device 502 for a display, according to another exemplary embodiment.
[0685] [0685] Referring to FIG. 82A and FIG. 82B, the light-emitting device 502 according to the exemplary embodiment illustrated is generally similar to the light-emitting device 500 described with reference to FIG. 70A and FIG. 70B, except that the anodes of the first to the third LED batteries 523, 533 and 543 are independently connected to the first to the third electrode pads 5173a, 5173b and 5173c, and their cathodes are electrically connected to a common electrode pad 5173d.
[0686] [0686] More particularly, the first electrode pad 5173a is electrically connected to the pad region 525a of the first ohmic electrode 525 through a through-hole path 5163b, the second electrode pad 5173b is electrically connected to the pad region 535a of the second ohmic electrode 535 through a through hole port 5165b and the third electrode pad 5173c is electrically connected to the pad region 545a of the third ohmic electrode 545 through a through hole way 5167b. The common electrode pad 5173d is electrically connected to an ohmic electrode 5163a exposed through the opening 571a of the upper insulation layer 571, and is also electrically connected to the first semiconductor layers of conductivity type 533a and 543a of the second LED stack 533 and the third stack of LEDs 545 through the orifice pathways 5165a and 5167a. For example, the 5165a through-hole path can be connected to the first conductivity type 533a semiconductor layer, and the 5175a through-hole path can be connected to the ohmic electrode 546 in ohmic contact with the first semiconductor layer of conductivity. conductivity type 543a.
[0687] [0687] Each of the light-emitting devices 500, 502 according to the exemplary modalities includes the first to the third LED batteries 523, 533 and 543, which can emit red, green and blue light, respectively, and therefore can be used as a pixel on a display device. As described in FIG. 69, the display device can be realized by arranging a plurality of light-emitting devices 500 or 502 on circuit board 501. As each of the light-emitting devices 500, 502 includes the first to the third LED batteries 523, 533 and 543 , you can increase the area of a subpixel by one pixel. In addition, the first to third LED batteries 523, 533 and 543 can be mounted on circuit board 501 by mounting a light-emitting device, thereby reducing the number of assembly processes.
[0688] [0688] As described in FIG. 69, the light-emitting devices mounted on the circuit board 501 can be activated passively by matrix or by active matrix.
[0689] [0689] Although certain exemplary modalities and implementations have been described here, other modalities and modifications will be evident from this description. Therefore, the inventive concepts are not limited to these modalities, but to the broader scope of the appended claims and to several obvious modifications and equivalent arrangements, as would be evident to a person skilled in the art.

权利要求:
Claims (22)
[1]
1. Light-emitting device, characterized by comprising a first substrate; a first LED subunit arranged under the first substrate; a second LED subunit arranged under the first LED subunit; a third LED subunit arranged under the second LED subunit; a first transparent electrode interposed between the first and the second LED subunit and in ohmic contact with a lower surface of the first LED subunit; a second transparent electrode interposed between the second and third LED subunits and in ohmic contact with a lower surface of the second LED subunit; a third transparent electrode interposed between the second transparent electrode and the third LED subunit, and in ohmic contact with the upper surface of the third LED subunit; at least one current spreader connected to at least one of the first, second and third LED subunits; electrode pads arranged on the first substrate; and through-hole paths formed through the first substrate to electrically connect the electrodes to the first, second and third LED subunits, wherein at least one of the through-hole paths is formed through the first substrate, the first LED subunit and the second LED subunit.
[2]
2. Light-emitting device according to claim 1, characterized in that the first, second and third LED subunits comprise the first, second and third LED batteries configured to emit red light, green light and blue light, respectively.
[3]
3. Light-emitting device according to claim 1, characterized in that it also comprises a Bragg reflector distributed between the first substrate and the first LED subunit.
[4]
Light emitting device according to claim 1, characterized in that the first substrate comprises GaAs.
[5]
Light-emitting device according to claim 4, characterized in that it further comprises a second substrate disposed under the third LED subunit.
[6]
6. Light-emitting device according to claim 5, characterized in that the second substrate is a sapphire substrate or a GaN substrate.
[7]
7. Light-emitting device according to claim 5, characterized in that the first LED subunit, the second LED subunit and the third LED subunit are independently operable; the light generated from the first LED subunit is configured to be emitted to the outside of the light emitting device through the second LED subunit, the third LED subunit and the second substrate; and the light generated from the second LED subunit is configured to be emitted to the outside of the light emitting device through the third LED subunit and the second substrate.
[8]
8. Light-emitting device according to claim 1, characterized in that the electrode pads comprise: an electrode pad commonly connected electrically to the first, second and third LED subunits; and a first electrode pad, a second electrode pad and a third electrode pad electrically connected to the first LED subunit, the second LED subunit and the third LED subunit, respectively.
[9]
9. Light-emitting device according to claim 8, characterized in that the common electrode pad is electrically connected to a plurality of through-hole paths.
[10]
10. Light-emitting device according to claim 8, characterized in that: the second electrode pad is electrically connected to the second LED subunit through a first through hole of the first substrate and the first LED subunit; and the third electrode pad is electrically connected to the third LED subunit through a second through hole of the first substrate, the first LED subunit and the second LED subunit.
[11]
11. Light-emitting device according to claim 10,
characterized by the first electrode being electrically connected to the first substrate.
[12]
12. Light-emitting device according to claim 10, characterized in that the first electrode pad is electrically connected to the first LED subunit through a third through hole of the first substrate.
[13]
13. Light-emitting device according to claim 11, characterized in that: the at least one current spreader comprises: a first current spreader connected to the first LED subunit; a second current spreader connected to the second LED subunit; and a third current spreader connected to the third LED subunit; and the first, second and third current spreaders are separated from the first, second and third transparent electrodes, respectively.
[14]
14. Light-emitting device according to claim 1, characterized in that one of the electrode pads disposed on the first substrate is electrically connected to the first, second and third transparent electrodes through a plurality of through-hole paths.
[15]
15. Light-emitting device according to claim 1, characterized in that one of the electrode pads arranged on the first substrate is connected to the first substrate.
[16]
16. Light-emitting device according to claim 1, further comprising: a first colored filter disposed between the third transparent electrode and the second transparent electrode; and a second colored filter disposed between the second LED subunit and the first transparent electrode.
[17]
17. Light-emitting device according to claim 16, characterized in that the first color filter and the second color filter comprise the insulation layers with different refractive indices.
[18]
18. Light-emitting device according to claim 1, characterized in that it further comprises an insulation layer disposed between the first substrate and the electrode pads and covering the side surfaces of the first, second and third LED subunits.
[19]
19. Light-emitting device according to claim 1, characterized in that the at least one current spreader has a body that at least partially surrounds one of the via orifice path and a projection extending outside the body.
[20]
20. Light-emitting device according to claim 19, characterized in that the body is substantially annular in shape and the projection is less than the diameter of the body.
[21]
21. Display device characterized by comprising a circuit board; and a plurality of light emitting devices arranged on the circuit board, at least one of the light emitting devices comprises: a first substrate; a first LED subunit arranged under the first substrate; a second LED subunit arranged under the first LED subunit; a third LED subunit arranged under the second LED subunit; a first transparent electrode interposed between the first and the second LED subunit and in ohmic contact with a lower surface of the first LED subunit; a second transparent electrode interposed between the second and third LED subunits and in ohmic contact with a lower surface of the second LED subunit; a third transparent electrode interposed between the second transparent electrode and the third LED subunit, and in ohmic contact with the upper surface of the third LED subunit; at least one current spreader connected to at least one of the first, second and third LED subunits; electrode pads arranged on the first substrate; and through hole paths formed through the first substrate to electrically connect the electrodes to the first, second and third LED subunits, wherein: at least one of the through hole paths is formed through the first substrate, the first LED subunit and the second LED subunit; and the electrode pads of the light emitting device are electrically connected to the circuit board.
[22]
22. Display device according to claim 21, characterized in that each of the light-emitting devices further comprises a second substrate coupled to the third LED subunit.

类似技术:

---

公开号 | 公开日 | 专利标题

---

BR112020011226A2|2020-11-17|light emitting device for display and display device having the same

---

US10892296B2|2021-01-12|Light emitting device having commonly connected LED sub-units

---

BR112020010671A2|2020-11-10|led unit for display and display device having the same

---

BR112020012281A2|2020-11-24|led unit for display and display device having the same

---

US20190164944A1|2019-05-30|Led unit for display and display apparatus having the same

---

BR112020013410A2|2020-12-01|display device with stacked light-emitting structure

---

BR112020012296A2|2020-11-24|stacked light-emitting structure and display device including the same

---

BR112020010653A2|2021-01-26|LED light for display and display device having the same

---

BR112020011233A2|2020-11-17|stacked light-emitting structure and display device including the same

---

US20220005971A1|2022-01-06|Passivation covered light emitting unit stack

---

US20200373284A1|2020-11-26|Light emitting device with led stack for display and display apparatus having the same

---

US11282981B2|2022-03-22|Passivation covered light emitting unit stack

---

US20220085239A1|2022-03-17|Passivation covered light emitting unit stack

同族专利:

---

公开号 | 公开日

---

CN111524880A|2020-08-11|

---

EP3721484A4|2021-09-01|

---

US20190214373A1|2019-07-11|

---

CN111508940A|2020-08-07|

---

JP2021506107A|2021-02-18|

---

EP3721484A1|2020-10-14|

---

US20200185363A1|2020-06-11|

---

US10748881B2|2020-08-18|

---

CN110770919A|2020-02-07|

---

CN111508939A|2020-08-07|

---

CN111508938A|2020-08-07|

---

KR20200085788A|2020-07-15|

---

WO2019112304A1|2019-06-13|

引用文献:

---

公开号 | 申请日 | 公开日 | 申请人 | 专利标题

---

---

JPH07254732A|1994-03-15|1995-10-03|Toshiba Corp|Semiconductor light emitting device|

---

US5703436A|1994-12-13|1997-12-30|The Trustees Of Princeton University|Transparent contacts for organic devices|

---

US5583349A|1995-11-02|1996-12-10|Motorola|Full color light emitting diode display|

---

KR100298205B1|1998-05-21|2001-08-07|오길록|Integrated tri-color light emitting diode and method for fabricating the same|

---

US6459100B1|1998-09-16|2002-10-01|Cree, Inc.|Vertical geometry ingan LED|

---

US6853411B2|2001-02-20|2005-02-08|Eastman Kodak Company|Light-producing high aperture ratio display having aligned tiles|

---

JP3643328B2|2001-08-21|2005-04-27|ファナック株式会社|Two-dimensional LD array light emitting device|

---

US6717358B1|2002-10-09|2004-04-06|Eastman Kodak Company|Cascaded organic electroluminescent devices with improved voltage stability|

---

CN1275337C|2003-09-17|2006-09-13|北京工大智源科技发展有限公司|High-efficiency high-brightness multiple active district tunnel reclaimed white light light emitting diodes|

---

JP2005190768A|2003-12-25|2005-07-14|Toyota Industries Corp|Lighting apparatus|

---

JP4608637B2|2004-02-09|2011-01-12|株式会社豊田自動織機|Transflective display with full color OLED backlight|

---

US7271420B2|2004-07-07|2007-09-18|Cao Group, Inc.|Monolitholic LED chip to emit multiple colors|

---

US20080128728A1|2004-09-10|2008-06-05|Luminus Devices, Inc.|Polarized light-emitting devices and methods|

---

WO2006054236A2|2004-11-19|2006-05-26|Koninklijke Philips Electronics N.V.|Composite led modules|

---

KR100665120B1|2005-02-28|2007-01-09|삼성전기주식회사|Vertical structure nitride semiconductor light emitting device|

---

JP4738407B2|2005-03-18|2011-08-03|富士通株式会社|Display device|

---

JP4636501B2|2005-05-12|2011-02-23|株式会社沖データ|Semiconductor device, print head, and image forming apparatus|

---

JP4869661B2|2005-08-23|2012-02-08|株式会社Ｊｖｃケンウッド|Display device|

---

JP2007095844A|2005-09-27|2007-04-12|Oki Data Corp|Semiconductor light-emitting composite device|

---

US8680693B2|2006-01-18|2014-03-25|Lg Chem. Ltd.|OLED having stacked organic light-emitting units|

---

US20070222922A1|2006-03-22|2007-09-27|Eastman Kodak Company|Graded contrast enhancing layer for use in displays|

---

US7808013B2|2006-10-31|2010-10-05|Cree, Inc.|Integrated heat spreaders for light emitting devices and related assemblies|

---

JP5030742B2|2006-11-30|2012-09-19|株式会社半導体エネルギー研究所|Light emitting element|

---

KR20080054626A|2006-12-13|2008-06-18|엘지디스플레이 주식회사|Organic electro luminescence display device and fabricating method thereof|

---

TWI440210B|2007-01-22|2014-06-01|Cree Inc|Illumination devices using externally interconnected arrays of light emitting devices, and methods of fabricating same|

---

JP2008263127A|2007-04-13|2008-10-30|Toshiba Corp|Led apparatus|

---

US20080308819A1|2007-06-15|2008-12-18|Tpo Displays Corp.|Light-Emitting Diode Arrays and Methods of Manufacture|

---

US7687812B2|2007-06-15|2010-03-30|Tpo Displays Corp.|Light-emitting diode arrays and methods of manufacture|

---

US8058663B2|2007-09-26|2011-11-15|Iii-N Technology, Inc.|Micro-emitter array based full-color micro-display|

---

US7732803B2|2008-05-01|2010-06-08|Bridgelux, Inc.|Light emitting device having stacked multiple LEDS|

---

KR101458958B1|2008-06-10|2014-11-13|삼성전자주식회사|Semiconductor chip, semiconductor package, and method of fabricating the semiconductor chip|

---

DE102008030584A1|2008-06-27|2009-12-31|Osram Opto Semiconductors Gmbh|Method for producing an optoelectronic component and optoelectronic component|

---

KR101332794B1|2008-08-05|2013-11-25|삼성전자주식회사|Light emitting device, light emitting system comprising the same, and fabricating method of the light emitting device and the light emitting system|

---

EP2332195A2|2008-08-19|2011-06-15|Plextronics, Inc.|Organic light emitting diode lighting devices|

---

JP5097057B2|2008-08-29|2012-12-12|株式会社沖データ|Display device|

---

JP4555880B2|2008-09-04|2010-10-06|株式会社沖データ|Multilayer semiconductor light emitting device and image forming apparatus|

---

JP5024247B2|2008-09-12|2012-09-12|日立電線株式会社|Light emitting element|

---

TW201017863A|2008-10-03|2010-05-01|Versitech Ltd|Semiconductor color-tunable broadband light sources and full-color microdisplays|

---

KR101601621B1|2008-11-14|2016-03-17|삼성전자주식회사|Semiconductor Light Emitting Device|

---

US20100210160A1|2009-02-18|2010-08-19|3M Innovative Properties Company|Hydrophilic porous substrates|

---

EP2406821A2|2009-03-13|2012-01-18|Tessera, Inc.|Stacked microelectronic assemblies having vias extending through bond pads|

---

KR101077789B1|2009-08-07|2011-10-28|한국과학기술원|Manufacturing method for LED display and LED display manufactured by the same|

---

RU2012126145A|2009-11-24|2013-12-27|Юниверсити Оф Флорида Рисерч Фаундейшн, Инк.|METHOD AND DEVICE FOR PERCEPTION OF INFRARED RADIATION|

---

US8642363B2|2009-12-09|2014-02-04|Nano And Advanced Materials Institute Limited|Monolithic full-color LED micro-display on an active matrix panel manufactured using flip-chip technology|

---

US9236532B2|2009-12-14|2016-01-12|Seoul Viosys Co., Ltd.|Light emitting diode having electrode pads|

---

US20110204376A1|2010-02-23|2011-08-25|Applied Materials, Inc.|Growth of multi-junction led film stacks with multi-chambered epitaxy system|

---

KR101252032B1|2010-07-08|2013-04-10|삼성전자주식회사|Semiconductor light emitting device and method of manufacturing the same|

---

JP5333382B2|2010-08-27|2013-11-06|豊田合成株式会社|Light emitting element|

---

US9070851B2|2010-09-24|2015-06-30|Seoul Semiconductor Co., Ltd.|Wafer-level light emitting diode package and method of fabricating the same|

---

US9941319B2|2010-10-13|2018-04-10|Monolithic 3D Inc.|Semiconductor and optoelectronic methods and devices|

---

KR20120040011A|2010-10-18|2012-04-26|한국전자통신연구원|Light emitting diode|

---

JP5777879B2|2010-12-27|2015-09-09|ローム株式会社|Light emitting device, light emitting device unit, and light emitting device package|

---

CN102593303A|2011-01-05|2012-07-18|晶元光电股份有限公司|Light-emitting element with embolisms|

---

US20120236532A1|2011-03-14|2012-09-20|Koo Won-Hoe|Led engine for illumination|

---

JP5854419B2|2011-03-18|2016-02-09|国立大学法人山口大学|Multi-wavelength light emitting device and manufacturing method thereof|

---

US9052096B2|2011-04-27|2015-06-09|Jx Nippon Oil & Energy Corporation|Light extraction transparent substrate for organic EL element, and organic EL element using the same|

---

TW201248945A|2011-05-31|2012-12-01|Chi Mei Lighting Tech Corp|Light-emitting diode device and method for manufacturing the same|

---

US8884316B2|2011-06-17|2014-11-11|Universal Display Corporation|Non-common capping layer on an organic device|

---

JP2013070030A|2011-09-06|2013-04-18|Sony Corp|Imaging device, electronic apparatus, and information processor|

---

KR101902392B1|2011-10-26|2018-10-01|엘지이노텍 주식회사|Light emitting device|

---

KR20130104612A|2012-03-14|2013-09-25|서울바이오시스 주식회사|Light emitting diode and method of fabricating the same|

---

US20130264587A1|2012-04-04|2013-10-10|Phostek, Inc.|Stacked led device using oxide bonding|

---

TW201344955A|2012-04-27|2013-11-01|Phostek Inc|Light emitting diode device|

---

US9257665B2|2012-09-14|2016-02-09|Universal Display Corporation|Lifetime OLED display|

---

US8946052B2|2012-09-26|2015-02-03|Sandia Corporation|Processes for multi-layer devices utilizing layer transfer|

---

US20140191243A1|2013-01-08|2014-07-10|University Of Florida Research Foundation, Inc.|Patterned articles and light emitting devices therefrom|

---

US9443833B2|2013-01-31|2016-09-13|Nthdegree Technologies Worldwide Inc.|Transparent overlapping LED die layers|

---

JP2014175427A|2013-03-07|2014-09-22|Toshiba Corp|Semiconductor light-emitting element and method of manufacturing the same|

---

TW201438188A|2013-03-25|2014-10-01|Miracle Technology Co Ltd|Stacked LED array structure|

---

JP2015012044A|2013-06-26|2015-01-19|株式会社東芝|Semiconductor light-emitting element|

---

KR102050461B1|2013-06-28|2019-11-29|엘지디스플레이 주식회사|Organic Light Emitting Device|

---

JP2015012244A|2013-07-01|2015-01-19|株式会社東芝|Semiconductor light-emitting element|

---

JP6497647B2|2013-12-24|2019-04-10|パナソニックＩｐマネジメント株式会社|Display device and manufacturing method of display device|

---

KR101452801B1|2014-03-25|2014-10-22|광주과학기술원|Light emitting diode and method for manufacturing thereof|

---

US9799719B2|2014-09-25|2017-10-24|X-Celeprint Limited|Active-matrix touchscreen|

---

JP2016027361A|2014-07-01|2016-02-18|株式会社リコー|Electrochromic display device, and manufacturing method and driving method of the same|

---

KR20160027875A|2014-08-28|2016-03-10|서울바이오시스 주식회사|Light emitting device|

---

KR101888608B1|2014-10-17|2018-09-20|엘지이노텍 주식회사|Light emitting device package and lighting apparatus|

---

US9847051B2|2014-11-04|2017-12-19|Apple Inc.|Organic light-emitting diode display with minimized subpixel crosstalk|

---

US9698134B2|2014-11-27|2017-07-04|Sct Technology, Ltd.|Method for manufacturing a light emitted diode display|

---

KR20160085605A|2015-01-08|2016-07-18|엘지이노텍 주식회사|Light emitting device package|

---

KR102038443B1|2015-03-26|2019-10-30|엘지이노텍 주식회사|Light emitting device and light emitting device package|

---

KR20160115301A|2015-03-26|2016-10-06|엘지이노텍 주식회사|Light emitting device package|

---

KR101771461B1|2015-04-24|2017-08-25|엘지전자 주식회사|Display device using semiconductor light emitting device and method for manufacturing the same|

---

US20160336482A1|2015-05-12|2016-11-17|Epistar Corporation|Light-emitting device|

---

DE102015108545A1|2015-05-29|2016-12-01|Osram Opto Semiconductors Gmbh|Optoelectronic component and method for producing an optoelectronic component|

---

DE102015108532A1|2015-05-29|2016-12-01|Osram Opto Semiconductors Gmbh|Display device with a plurality of separately operable pixels|

---

JP2016225221A|2015-06-02|2016-12-28|コニカミノルタ株式会社|Electroluminescence device|

---

KR20170021760A|2015-08-18|2017-02-28|엘지이노텍 주식회사|Light emitting device, light emitting device package including the device, and light emitting apparatus including the package|

---

KR20170024923A|2015-08-26|2017-03-08|삼성전자주식회사|light emitting diode package and apparatus including the same|

---

KR20170027906A|2015-09-02|2017-03-13|삼성전자주식회사|Led driving apparatus and light apparatus including the same|

---

KR20170031289A|2015-09-10|2017-03-21|삼성전자주식회사|Semiconductor light emitting device|

---

KR101739851B1|2015-10-30|2017-05-25|주식회사 썬다이오드코리아|Light emitting device comprising wavelength conversion structures|

---

TWI581455B|2016-01-29|2017-05-01|友達光電股份有限公司|Light emitting device and manufacturing method of light emitting device|

---

KR20170095418A|2016-02-12|2017-08-23|삼성전자주식회사|Lighting source module, display panel and display apparatus|

---

WO2017146477A1|2016-02-26|2017-08-31|서울반도체주식회사|Display apparatus and method for producing same|

---

DE102016104280A1|2016-03-09|2017-09-14|Osram Opto Semiconductors Gmbh|Component and method for manufacturing a device|

---

CN205944139U|2016-03-30|2017-02-08|首尔伟傲世有限公司|Ultraviolet ray light -emitting diode spare and contain this emitting diode module|

---

KR20170115142A|2016-04-04|2017-10-17|삼성전자주식회사|Led lighting source module and display apparatus|

---

JP6683003B2|2016-05-11|2020-04-15|日亜化学工業株式会社|Semiconductor element, semiconductor device, and method for manufacturing semiconductor element|

---

KR20170129983A|2016-05-17|2017-11-28|삼성전자주식회사|Led lighting device package, display apparatus using the same and method of manufacuring process the same|

---

US10388691B2|2016-05-18|2019-08-20|Globalfoundries Inc.|Light emitting diodes with stacked multi-color pixels for displays|

---

EP3297044A1|2016-09-19|2018-03-21|Nick Shepherd|Improved led emitter, led emitter array and method for manufacturing the same|

---

US20180156965A1|2016-12-01|2018-06-07|Ostendo Technologies, Inc.|Polarized Light Emission From Micro-Pixel Displays and Methods of Fabrication Thereof|

---

US10400958B2|2016-12-30|2019-09-03|Lumileds Llc|Addressable color changeable LED structure|

---

CN106898601A|2017-02-15|2017-06-27|佛山市国星光电股份有限公司|LED circuit board, triangle LED component and display screen that triangle is combined|

---

TWI613806B|2017-05-16|2018-02-01|錼創科技股份有限公司|Micro light-emitting diode apparatus and display panel|

---

KR20190026440A|2017-09-05|2019-03-13|삼성전자주식회사|Display device using light emitting diode|

---

KR20190069869A|2017-12-12|2019-06-20|삼성전자주식회사|Method of fabricating light emitting device package|

---

US10586829B2|2018-01-23|2020-03-10|Light Share, LLC|Full-color monolithic micro-LED pixels|JP2019149480A|2018-02-27|2019-09-05|豊田合成株式会社|Semiconductor element, light-emitting device, and method for manufacturing light-emitting device|

---

US10886447B2|2018-09-14|2021-01-05|Seoul Viosys Co., Ltd.|Light emitting device|

---

CN109300887A|2018-09-30|2019-02-01|武汉华星光电技术有限公司|Back lighting device and its manufacturing method|

---

US11158665B2|2018-11-05|2021-10-26|Seoul Viosys Co., Ltd.|Light emitting device|

---

US11211528B2|2019-03-13|2021-12-28|Seoul Viosys Co., Ltd.|Light emitting device for display and display apparatus having the same|

---

US10796928B1|2019-06-27|2020-10-06|Advanced Semiconductor Engineering, Inc.|Wiring structure and method for manufacturing the same|

---

DE102019119891A1|2019-07-23|2021-01-28|OSRAM Opto Semiconductors Gesellschaft mit beschränkter Haftung|OPTOELECTRONIC SEMICONDUCTOR CHIP AND METHOD FOR MANUFACTURING AN OPTOELECTRONIC SEMICONDUCTOR CHIP|

---

US10971650B2|2019-07-29|2021-04-06|Lextar Electronics Corporation|Light emitting device|

---

US11038088B2|2019-10-14|2021-06-15|Lextar Electronics Corporation|Light emitting diode package|

---

KR102273917B1|2019-10-15|2021-07-07|주식회사 썬다이오드코리아|Pixel for Micro Display and Method of manufacturing the same|

---

US20210151421A1|2019-11-15|2021-05-20|Seoul Viosys Co., Ltd.|Light emitting device for display and display apparatus having the same|

---

US20210181267A1|2019-12-17|2021-06-17|Seoul Viosys Co., Ltd.|Micro led bond tester and method of evaluating micro led bond using same|

---

US20210202567A1|2019-12-29|2021-07-01|Seoul Viosys Co., Ltd.|Light emitting device for display and unit pixel having the same|

---

US20210375980A1|2020-05-28|2021-12-02|Seoul Viosys Co., Ltd.|Light emitting device and display apparatus having the same|

---

CN111969087A|2020-08-28|2020-11-20|厦门乾照光电股份有限公司|LED chip based on transparent substrate and preparation method thereof|

法律状态:
2021-12-07| B350| Update of information on the portal [chapter 15.35 patent gazette]|

优先权:

---

申请号 | 申请日 | 专利标题

---

US201762594754P| true| 2017-12-05|2017-12-05|

---

US62/594,754|2017-12-05|

---

US201762608006P| true| 2017-12-20|2017-12-20|

---

US62/608,006|2017-12-20|

---

US201862649500P| true| 2018-03-28|2018-03-28|

---

US62/649,500|2018-03-28|

---

US201862651585P| true| 2018-04-02|2018-04-02|

---

US62/651,585|2018-04-02|

---

US201862657575P| true| 2018-04-13|2018-04-13|

---

US62/657,575|2018-04-13|

---

US16/207,881|US10748881B2|2017-12-05|2018-12-03|Light emitting device with LED stack for display and display apparatus having the same|

---

US16/207,881|2018-12-03|

---

PCT/KR2018/015268|WO2019112304A1|2017-12-05|2018-12-04|Light emitting device with led stack for display and display apparatus having the same|

---