led unit for display and display device having the same

专利摘要:
LED UNIT FOR DISPLAY AND DISPLAY DEVICE HAVING THE SAME, comprises a stack of light emitting diodes (LED) for a display including a first LED subunit with a first surface and a second surface, a second LED subunit arranged on the first surface of the first LED subunit, a third LED subunit arranged in the second LED subunit, a reflective electrode disposed on the second side of the second LED subunit and forming ohmic contact with the first LED subunit and an ohmic electrode interposed between the first subunit LED and the second LED subunit and forming ohmic contact with the first LED subunit, in which the second LED subunit and the third LED subunit are configured to transmit light generated from the first LED subunit, and the third subunit LED is configured to transmit the light generated from the second LED subunit.
公开号:BR112020010671A2
申请号:R112020010671-2
申请日:2018-11-27
公开日:2020-11-10
发明作者:Jong Hyeon Chae；Chung Hoon Lee；Seong Gyu Jang；Chang Yeon Kim；Ho Joon Lee
申请人:Seoul Viosys Co., Ltd.；
IPC主号:

专利说明:

[001] [001] Exemplary implementations of the invention generally refer to light emitting diodes and, more particularly, a micro light emitting diode ("micro LED") for next generation display and a display device including the same.
[002] [002] Light emitting diodes (LEDs) have been used as an inorganic light source in a wide range of fields, such as display devices, automotive lamps, general lighting and the like. The light emitting diode is rapidly replacing existing light sources due to its longer life, lower power consumption and faster, faster response.
[003] [003] A typical light-emitting diode has generally been used as a backlight source in a display device. However, recently, micro LEDs have been developed as a next generation display device that directly implements images from light emitting diodes.
[004] [004] In general, a display device implements several colors using mixed colors of blue, green and red. As such. Each pixel on the display device includes blue, green, and red subpixels, and the color of the specific pixel is determined by the colors of those subpixels, and an image is implemented by a combination of these pixels.
[005] [005] In a micro LED display, the micro LEDs are arranged in a two-dimensional plane to correspond to each pixel and, therefore, a large number of micro LEDs must be placed on a substrate, usually in millions or tens of millions. However, the small form factor of the micro LED, which generally has a surface area of around 10,000 square micrometers or less, can cause several problems during the manufacture of a display device. For example, handling a micro LED is difficult and, therefore, it is difficult to mount the micro LEDs on a display panel, especially when it is necessary to transfer millions to make a single display. In addition, it is difficult to replace a defective micro LED when the micro LED is mounted on the display panel.
[006] [006] In addition, since the subpixels are arranged in a two-dimensional plane, an area occupied by a pixel that includes blue, green and red subpixels is relatively large. As such, organizing the subpixels within a limited area may require reducing the area of each subpixel, which in turn can deteriorate the brightness of the subpixels due to the reduction of the luminous areas.
[007] [007] The information disclosed in this section of Fundamentals is only for the understanding of the foundations of the inventive concepts and, therefore, may contain information that does not constitute the prior art. Technical issue
[008] [008] Light emitting diodes built according to the principles and some exemplary implementations of the invention and displays using them are able to increase the light emitting area of each LED subpixel without increasing the corresponding surface area of the pixel area and without degrading the display characteristics.
[009] [009] Light-emitting diodes built according to the principles and some exemplary implementations of the invention and displays using them have a sub-pixel structure in which at least two of the sub-pixels are stacked vertically, thus reducing the surface area needed to implement the display.
[010] [010] Light-emitting diodes built according to the principles and some exemplary implementations of the invention and displays using them have sub-pixels that can be activated independently.
[011] [011] Light emitting diodes built according to the principles and some exemplary implementations of the invention and displays using them are particularly advantageous when built as micro LEDs. For example, micro LEDs built in accordance with the principles and some exemplary implementations of the invention are capable of being manufactured simultaneously in a plurality at the wafer level and thus avoid the need to mount the micro LEDs individually.
[012] [012] Light-emitting diodes built according to the principles and some exemplary implementations of the invention and displays using them advantageously employ a partial reflective layer between the red LED stack and the substrate and / or control a one-band band gap semiconductor of each LED stack, to control the brightness of each one pixel LED stack using micro LEDs.
[013] [013] 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.
[014] [014] A light emitting diode (LED) stack for a display, according to an exemplary embodiment, includes a support substrate, a first LED subunit arranged on the support substrate, a second LED subunit arranged on the first subunit LED, a third LED subunit positioned in the second LED subunit, a first color filter interposed between the first LED subunit and the second LED subunit and configured to transmit light generated in the first LED subunit and reflect light generated in the second LED subunit and a second color filter interposed between the second LED subunit and the third LED subunit, and configured to transmit light generated in the first and second LED subunits and reflect the light generated in the third LED subunit, in which the second LED subunit and third LED subunit are configured to transmit light generated in the first LED subunit and the third LED subunit is configured to t transmit light generated in the second LED subunit.
[015] [015] The first, second and third LED subunits can include first, second and third LED batteries, respectively.
[016] [016] The LED stack can include a micro LED with a surface area of less than about 10,000 µm square.
[017] [017] The second LED subunit and the third LED subunit can be configured to transmit the light generated in the first LED subunit to the outside of the micro LED stack and the third LED subunit can be configured to transmit the generated light in the second LED subunit to the outside of the micro LED stack.
[018] [018] The first, second and third LED batteries can be configured to emit red light, green light and blue light, respectively.
[019] [019] The first color filter and the second color filter can include at least one of a low pass filter, a bandpass filter and a band interrupt filter, respectively.
[020] [020] The first color filter and the second color filter can include a distributed Bragg reflector.
[021] [021] The LED stack for a display can also include a first interlayer bond between the support substrate and the first LED stack, a second interlayer bond between the first LED stack and the first color filter and a third link layer interposed between the second LED stack and the second color filter, in which the second link layer is configured to transmit light generated in the first LED stack and the third link layer is configured to transmit light generated in the first LED battery and the second LED battery.
[022] [022] The first bonding layer, the second bonding layer and the third bonding layer may include at least one transparent inorganic insulating film, a transparent organic insulating film and a thin transparent conductive film.
[023] [023] The LED stack for a display may also include a first reflective electrode disposed between the first link layer and the first LED stack and in ohmic contact with a p-type semiconductor layer of the first LED stack, a second electrode transparent disposed between the first color filter and the second LED stack and in ohmic contact with a p-type semiconductor layer of the second LED stack and a third transparent electrode disposed between the second color filter and the third LED stack and in ohmic contact with a p-type semiconductor layer of the third LED cell, in which the second transparent electrode and the third transparent electrode are configured to transmit the light generated in the first LED cell to the outside, and the third transparent electrode is configured to transmit the light generated in the second LED stack to the outside.
[024] [024] The second link layer may be in contact with a n-type semiconductor layer of the first LED stack and the third link layer may be in contact with a n-type semiconductor layer of the second LED stack.
[025] [025] The LED stack for a display can also include a first bonding layer interposed between the support substrate and the first LED stack, a second bonding layer interposed between the first color filter and the second LED stack and a third link layer interposed between the second LED stack and the second color filter, in which the second link layer and the third link layer are configured to transmit light generated in the first LED stack and the second LED stack.
[026] [026] The LED stack for a display may also include a first reflective electrode disposed between the first bonding layer and the first LED stack and in ohmic contact with a type n semiconductor layer of the first LED stack, a first electrode transparent disposed between the first LED stack and the first color filter and in ohmic contact with a p-type semiconductor layer of the first LED stack, a second transparent electrode disposed between the second LED stack and the third bonding layer and in ohmic contact with a p-type semiconductor layer of the second LED stack and a third transparent electrode disposed between the second color filter and the third LED stack and in ohmic contact with a p-type semiconductor layer of the third LED stack, in which the first, second and third transparent electrodes are configured to transmit the light generated in the first LED battery to the outside and the second and third transparent electrodes are configured to transmit the light generated in the second LED stack to the outside.
[027] [027] The LED stack for a display may also include a second reflective electrode disposed between the second bonding layer and the second LED stack, in which the second transparent electrode is in ohmic contact with a n-type semiconductor layer of the second LED stack.
[028] [028] A display device may include a plurality of pixels arranged on a support substrate, in which at least some of the pixels include the LED stack according to an exemplary embodiment.
[029] [029] Each of the first, second and third LED batteries can include a p-type semiconductor layer and an n-type semiconductor layer, the p-type semiconductor layers of each pixel can be electrically connected to a common line and the layers n-type semiconductors of each pixel can be electrically connected to different lines from each other.
[030] [030] The common line can include a data line and the different lines can include scan lines.
[031] [031] The display device may also include a bottom insulation layer covering the side surfaces of the first, second and third LED cells, in which the bottom insulation layer has an opening that exposes a portion of the first, second and third cells. LED.
[032] [032] The bottom insulation layer can include a distributed Bragg reflector configured to reflect red light, green light and blue light.
[033] [033] The display device may also include a reflective electrode disposed between the support substrate and the first LED stack, in which the reflective electrode includes the common line and is continuously disposed over the plurality of pixels.
[034] [034] The display device may also include a plurality of reflective electrodes disposed between the support substrate and the first LED stack, in which each reflective electrode is disposed within each pixel region.
[035] [035] The third LED stack may include a rough surface region on its upper surface.
[036] [036] The first, second and third LED batteries of each pixel can be activated independently.
[037] [037] An LED pixel for a display, according to an exemplary modality, includes a first LED subunit with a first surface and a second surface, a second LED subunit arranged on a portion of the first surface of the first LED subunit , a third LED subunit arranged in a portion of the second LED subunit, a reflective electrode disposed on the second surface of the first LED subunit, a second transparent electrode disposed between the second LED subunit and the third LED subunit, and in contact ohmic with the upper surface of the second LED subunit, and a third transparent electrode in contact ohmic with the upper surface of the third LED subunit, in which each of the first, second and third LED subunits includes a ne-type semiconductor layer p-type semiconductor layer, each of the n-type semiconductor layers of the first, second and third LED subunits is electrically connected to the reflector electrode and the first LED subunit, the second LED subunit and the third LED subunit are independent.
[038] [038] The first, second and third LED subunits can include first, second and third LED batteries, respectively.
[039] [039] The LED pixel can include a micro LED with a surface area of less than about 10,000 µm square.
[040] [040] The first LED battery, the second LED battery and the third LED battery can be configured to emit red light, green light and blue light, respectively.
[041] [041] A first portion of light generated in the first LED stack can be configured to be emitted to the outside without going through the second LED stack, a second portion of light generated in the first LED stack can be configured to be emitted to the exterior transmitting through the second LED battery and the second transparent electrode, a third portion of light generated in the first LED battery can be configured to be emitted to the outside by transmitting through the second LED battery, the second transparent electrode, the third battery LED, and the third transparent electrode, a first portion of light generated in the second LED battery can be configured to be emitted to the outside without going through the third LED battery, and a second portion of light generated in the second LED battery can be configured be configured to be emitted to the outside transmitting through the third battery of LED and the third transparent electrode.
[042] [042] Each of the p-type semiconductor layers of the first, second and third LED cells can be arranged in the corresponding n-type semiconductor layer, the reflecting electrode may be in ohmic contact with the n-type semiconductor layer of the first LED, and the second transparent electrode and the third transparent electrode can be in ohmic contact with the p-type semiconductor layers of the second LED stack and the third LED stack, respectively.
[043] [043] The LED pixel for a display can also include a first color filter interposed between the first LED stack and the second LED stack and a second color filter interposed between the second LED stack and the third LED stack. , in which the first color filter is configured to transmit light generated in the first LED stack and reflect the light generated in the second LED stack, and the second color filter is configured to transmit light generated in the second LED stack and reflect the light generated in the third LED stack.
[044] [044] The first color filter can contact the n-type semiconductor layer of the second LED stack, and the second color filter can contact the n-type semiconductor layer of the third LED stack.
[045] [045] The LED pixel for a screen can also include a first interconnection layer between the first LED stack and the first color filter and a second interconnection layer between the second LED stack and the second color filter. , in which the second link layer is configured to transmit light generated in the first LED stack and the third link layer is configured to transmit light generated in the second LED stack.
[046] [046] The LED pixel for a screen can also include a first ohmic electrode in ohmic contact with the p-type semiconductor layer of the first LED cell, a second ohmic electrode in contact with the n-type semiconductor layer of the second LED cell. LED, a third ohmic electrode in contact with the n-type semiconductor layer of the third LED stack, a second current spreading layer disposed on the second transparent electrode and a third current spreading layer disposed on the third transparent electrode, on which the the second ohmic electrode is arranged on a portion of the n-type semiconductor layer of the second LED stack that does not overlap the third LED stack and the second current spreading layer is disposed on the second transparent electrode.
[047] [047] The third ohmic electrode and the third current spreading layer can include the same material.
[048] [048] The second ohmic electrode, the second current propagation layer, the third ohmic electrode and the third current spreading layer can include the same material.
[049] [049] The LED pixel for a display can also include a first current scattering layer disposed on the first ohmic electrode, in which the first ohmic electrode is transparent and the first, second and third current scattering layers comprise the same material .
[050] [050] A display device may include a plurality of pixels arranged on a support substrate, in which at least some of the pixels include the LED pixel according to an exemplary embodiment.
[051] [051] Each of the p-type semiconductor layers of the first, second and third LED cells can be electrically connected to different lines from each other.
[052] [052] An LED stack for a display, according to an exemplary embodiment, includes a first LED subunit with a first surface and a second surface, a second LED subunit arranged on the first surface of the first LED subunit, a third LED subunit arranged in the second LED subunit, a reflective electrode arranged on the second side of the second LED subunit and forming ohmic contact with the first LED subunit and an ohmic electrode interposed between the first LED subunit and the second LED subunit and forming ohmic contact with the first LED subunit, in which the second LED subunit and the third LED subunit are configured to transmit light generated from the first LED subunit, and the third LED subunit is configured to transmit the generated light from the second LED subunit.
[053] [053] The first, second and third LED subunits can include first, second and third LED batteries, respectively.
[054] [054] The LED stack can include a micro LED with a surface area of less than about 10,000 µm square.
[055] [055] The reflective electrode and the ohmic electrode can have different reflective indices from each other.
[056] [056] The first, second and third LED batteries can be configured to emit red light, green light and blue light, respectively.
[057] [057] The LED stack for a display can also include a first color filter interposed between the first LED stack and the second LED stack, and configured to transmit light generated from the first LED stack and reflect the generated light. from the second LED battery and a second color filter interposed between the second LED battery and the third LED battery, and configured to transmit the light generated from the first and second LED batteries and reflect the light generated at from the third LED stack.
[058] [058] Each of the first color filters and the second color filter can include at least one low pass filter, one bandpass filter and one band interrupt filter.
[059] [059] Each of the first and second color filters can include a distributed Bragg reflector.
[060] [060] The LED stack for a display can also include a support substrate, a first bonding layer interposed between the support substrate and the first LED stack, a second bonding layer interposed between the first LED stack and the second LED stack and a third link layer interposed between the second LED stack and the third LED stack, in which the second link layer is configured to transmit light generated from the first LED stack and the third link layer it is configured to transmit light generated from the first and second LED batteries.
[061] [061] The first bonding layer can bond to the reflecting electrode, and the second bonding layer can bond to the ohmic electrode.
[062] [062] The LED battery for a display can also include a second transparent electrode forming ohmic contact with a p-type semiconductor layer of the second LED cell and a third transparent electrode forming ohmic contact with a p-type semiconductor layer of the third cell LED.
[063] [063] The second link layer can join a type n semiconductor layer on the first LED stack, and the third link layer can join a type n semiconductor layer on the second LED stack.
[064] [064] The LED stack for a display can also include a first color filter interposed between the first LED stack and the second LED stack and configured to transmit light generated from the first LED stack and reflect the light generated from from the second LED battery and a second color filter interposed between the second LED battery and the third LED battery, and configured to transmit light generated from the first and second LED batteries and reflect the light generated from the third LED stack, in which the first color filter is disposed in the second connection layer and the second color filter is disposed in the third connection layer.
[065] [065] A display device may include a plurality of pixels arranged on a support substrate, in which at least some of the pixels include the LED stack according to an exemplary embodiment.
[066] [066] Each of the first, second and third LED cells can include a p-type semiconductor layer and an n-type semiconductor layer, each of the p-type semiconductor layers of the first, second and third LED cells can be electrically connected to a common line and each of the n-type semiconductor layers of the first, second and third LED cells can be electrically connected to different lines from each other.
[067] [067] The common line can include a data line and the different lines can include scan lines.
[068] [068] The display device may also include a bottom insulation layer that covers the side surfaces of the first, second and third LED batteries, the bottom insulation layer including openings that expose the ohmic electrode, the reflective electrode, the second battery LED and the third LED stack.
[069] [069] The bottom insulation layer can include a distributed Bragg reflector configured to reflect red, green and blue light.
[070] [070] The reflecting electrode can include the common line and can be placed continuously over the plurality of pixels.
[071] [071] The reflecting electrode can be arranged within each pixel region.
[072] [072] An LED battery for a display, according to an exemplary modality, includes a first LED subunit configured to emit a first colored light, a second LED subunit positioned on the first LED pile and configured to emit a second colored light and a third LED subunit positioned in at least one of the first LED subunit and the second LED subunit and configured to emit a third colored light, in which the first LED subunit is configured to emit light through the second LED subunit and the third LED subunit and the second LED subunit are configured to emit light through the third LED subunit.
[073] [073] The first, second and third LED subunits can include first, second and third LED batteries, respectively.
[074] [074] The LED stack can include a micro LED with a surface area of less than about 10,000 µm square.
[075] [075] The first colored light may have a longer wavelength than the second colored light and the second colored light may have a longer wavelength than the third colored light.
[076] [076] The first, second and third colored lights can be red light, green light and blue light, respectively.
[077] [077] The first LED stack can be configured to generate light when a portion of the second colored light is incident on it, and the second LED stack can be configured to generate light when a portion of the third colored light is incident on it.
[078] [078] The intensity of the second colored light emitted to the outside can be at least about 10 times the intensity of the first colored light emitted by the second colored light, and the intensity of the third colored light emitted to the outside can be at least about 10 times the intensity of the second colored light caused by the third colored light.
[079] [079] The LED stack for a display can also include a support substrate, a reflective electrode interposed between the first LED stack and the support substrate and form an ohmic contact with the first LED stack and an ohmic electrode interposed between the first LED stack and the second LED stack and forming ohmic contact with the first LED stack.
[080] [080] The LED stack for a display can also include a first interlayer bonding layer between the support substrate and the first LED stack, a second interlayer bonding layer between the first LED stack and the second LED stack and a third link layer interposed between the second LED stack and the third LED stack, in which the second link layer is configured to transmit the first colored light and the third link layer is configured to transmit the first colored light and the second colored light.
[081] [081] The first bonding layer can join the reflecting electrode and the second bonding layer can join the ohmic electrode.
[082] [082] The LED stack for a display can also include a second transparent electrode forming ohmic contact with a p-type semiconductor layer from the second LED cell and a third transparent electrode forming ohmic contact with a p-type semiconductor layer from the third cell LED.
[083] [083] The second link layer can join a n-type semiconductor layer from the first LED stack and the third link layer joins a n-type semiconductor layer from the second LED stack.
[084] [084] A display device may include a plurality of pixels arranged on the support substrate, in which at least some of the pixels include the LED stack according to an exemplary embodiment.
[085] [085] The first LED battery can have a first area, a second area and a third area, the first area cannot be overlaid by the second and third LED batteries in the plan view, the second area can be overlaid by the second battery LED and not overlapped by the third LED battery in the plan view, and the third area can be overlaid by the second and third LED batteries in the plan view.
[086] [086] The first, second and third LED batteries can be substantially the same width in the plan view.
[087] [087] The width of the first LED battery can be greater than the second or third LED battery in the plan view.
[088] [088] The display device may also include a lower insulation layer covering the side surfaces of the first, second and third LED batteries, in which the lower insulation layer includes openings that expose an ohmic electrode, the reflective electrode, the second LED battery and the third LED battery.
[089] [089] The bottom insulation layer may include a distributed Bragg reflector configured to reflect red, green and blue light.
[090] [090] Each of the first, second and third LED cells can include a p-type semiconductor layer and an n-type semiconductor layer, and each of the p-type semiconductor layers of the first, second and third LED cells can be connected electrically to a common line, and each of the n-type semiconductor layers of the first, second and third LED cells can be electrically connected to different lines from each other.
[091] [091] The reflecting electrode can include the common line and can be placed continuously over the plurality of pixels.
[092] [092] The reflecting electrode can be disposed within each pixel region.
[093] [093] The first, second and third LED batteries can be configured to operate independently.
[094] [094] An LED pixel for a display, according to an exemplary modality, includes a substrate, a first LED subunit arranged on the substrate, a second LED subunit located on the first LED subunit, a third LED subunit arranged on at least one of the first and second LED subunits and pathways on the substrate, in which each of the first, second and third LED subunits includes a first conductivity type semiconductor layer and a second conductivity type semiconductor layer and each of the pathways is electrically connected to at least one of the first, second and third LED subunits.
[095] [095] The first, second and third LED subunits can include first, second and third LED batteries, respectively.
[096] [096] The LED pixel can include a micro LED with a surface area of less than about 10,000 µm square.
[097] [097] The first LED battery, the second LED battery and the third LED battery can be configured to emit light with different wavelengths.
[098] [098] The first LED battery, the second LED battery and the third LED battery can be configured to emit red light, green light and blue light, respectively.
[099] [099] The substrate may include a GaAs substrate, and the first LED stack comprises layers of semiconductors based on AlGaInP.
[0100] [0100] The LED pixel for a display can also include a distributed Bragg reflector interposed between the substrate and the first LED stack, in which the distributed Bragg reflector can include semiconductor layers.
[0101] [0101] The distributed Bragg reflector can include layers of AlAs and layers of AlGaAs arranged alternately with each other.
[0102] [0102] The LED pixel for a display can also include a first layer of interconnection between the first battery of LED and the second stack of LED, and a second layer of connection interposed between the second battery of LED and the third battery of LED.
[0103] [0103] The LED pixel for a display can also include a second lower ohmic electrode interposed between the first link layer and the second LED battery and form ohmic contact with the second LED battery and a third lower ohmic electrode interposed between the second connection layer and the third LED battery and forming ohmic contact with the third LED battery.
[0104] [0104] Each of the second lower ohmic electrode and the third lower ohmic electrode may include a reflective layer.
[0105] [0105] The tracks can include first, second and third tracks, the first track can be electrically connected to the second conductivity type semiconductor layer of the first LED stack, the second track can be electrically connected to the second conductivity type semiconductor layer of the second LED stack and the third path can be electrically connected to the second conductivity type semiconductor layer of the third LED stack.
[0106] [0106] The first conductivity type semiconductor layers of the first, second and third LED cells can be electrically connected to each other.
[0107] [0107] The LED for a display may also include a first upper ohmic electrode that comes into contact with the first conductivity type semiconductor layer of the first LED stack, a first lower ohmic electrode that comes into contact with the second semiconductor layer of conductivity. conductivity type of the first LED cell, a second upper ohmic electrode that comes into contact with the first conductivity type semiconductor layer of the second LED stack, a second lower ohmic electrode coming into contact with the second conductivity type semiconductor layer of the second LED cell, a third upper ohmic electrode contacting the first conductivity type semiconductor layer of the third LED cell and a third lower ohmic electrode contacting the second conductivity type semiconductor layer of the third cell LED, in which the first, second and third tracks are electrically connected to the first electr lower ohmic anode, the second lower ohmic electrode and the third lower ohmic electrode, respectively, and the first upper ohmic electrode, the second upper ohmic electrode and the third upper ohmic electrode are electrically connected to each other.
[0108] [0108] The LED pixel for a display can also include connection pads arranged on a lower surface of the substrate, in which the tracks are connected to the connection pads, respectively.
[0109] [0109] Link pads can include first link pads isolated from the substrate and at least one second link pad electrically connected to the substrate, and the tracks can be connected electrically to the first link pads, respectively.
[0110] [0110] A display device can include a circuit board and a plurality of pixels arranged on the circuit board, in which at least some of the pixels include the LED pixel according to an exemplary embodiment.
[0111] [0111] The circuit board can include at least one of a passive circuit and an active circuit, and the paths are electrically connected to the circuit board.
[0112] [0112] The substrate can be placed continuously over the plurality of pixels and is connected to the ground through an electrical connection to the circuit board.
[0113] [0113] The display device may also include electrode pads interposed between the substrate and the circuit board, in which at least one of the electrode pads is electrically connected to the substrate and the tracks are electrically connected to the circuit board via the pads electrode.
[0114] [0114] 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.
[0115] [0115] Light emitting diodes built according to the principles and some exemplary implementations of the invention and displays using them are able to increase the light emitting area of each LED subpixel without increasing the corresponding surface area of the pixel area and without degrading the display characteristics.
[0116] [0116] Light-emitting diodes built according to the principles and some exemplary implementations of the invention and displays using them have a sub-pixel structure in which at least two of the sub-pixels are stacked vertically, thus reducing the surface area required to implement the display.
[0117] [0117] Light emitting diodes built according to the principles and some exemplary implementations of the invention and displays using them have sub-pixels that can be activated independently.
[0118] [0118] Light emitting diodes built according to the principles and some exemplary implementations of the invention and displays using them are particularly advantageous when built as micro LEDs. For example, micro LEDs built in accordance with the principles and some exemplary implementations of the invention are capable of being manufactured simultaneously in a plurality at the wafer level and thus avoid the need to mount the micro LEDs individually.
[0119] [0119] Light-emitting diodes built according to the principles and some exemplary implementations of the invention and displays using them advantageously employ a partial reflective layer between the red LED stack and the substrate and / or control a layer band gap semiconductor of each LED stack, to control the brightness of each one pixel LED stack using micro LEDs.
[0120] [0120] 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.
[0121] [0121] FIG. 1 is a schematic cross-sectional view of a light emitting diode battery for a display according to an exemplary embodiment.
[0122] [0122] FIG. 2 is a schematic cross-sectional view illustrating a method of manufacturing a stack of light-emitting diodes for a display according to an exemplary embodiment.
[0123] [0123] FIG. 3 is a schematic circuit diagram of a display device according to an exemplary embodiment.
[0124] [0124] FIG. 4 is a schematic plan view of a display device according to an exemplary embodiment.
[0125] [0125] FIG. 5 is an enlarged one-pixel plan view of the display device of FIG. 4 according to an exemplary modality.
[0126] [0126] FIG. 6 is a schematic cross-sectional view taken along a line A-A of FIG. 5.
[0127] [0127] FIG. 7 is a schematic cross-sectional view taken along a line B-B of FIG. 5.
[0128] [0128] FIGS. 8A, 8B, 8C, 8D, 8E, 8F, 8G, 8H, 8I, 8J and 8K are schematic plan views that illustrate a method of manufacturing a display device according to an exemplary embodiment.
[0129] [0129] FIG. 9 is a schematic circuit diagram of a display device according to another exemplary embodiment.
[0130] [0130] FIG. 10 is a schematic plan view of a pixel according to another exemplary embodiment.
[0131] [0131] FIG. 11 is a schematic cross-sectional view of a light emitting diode stack for a display in accordance with yet another exemplary embodiment.
[0132] [0132] FIGS. 12A, 12B, 12C, 12D, 12E and 12F are schematic cross-sectional views illustrating a method of manufacturing a stack of light-emitting diodes for a display in accordance with yet another exemplary embodiment.
[0133] [0133] FIG. 13 is a schematic plan view of a display device according to an exemplary embodiment.
[0134] [0134] FIG. 14 is a schematic cross-sectional view of a pixel of LED light for a display according to an exemplary embodiment.
[0135] [0135] FIG. 15 is a schematic circuit diagram of a display device according to an exemplary embodiment.
[0136] [0136] FIG. 16 is a schematic plan view of a display device according to an exemplary embodiment.
[0137] [0137] FIG. 17 is an enlarged one-pixel plan view of the display device of FIG. 16 according to an exemplary modality.
[0138] [0138] FIG. 18A is a schematic cross-sectional view taken along a line A-A of FIG. 17 according to an exemplary modality.
[0139] [0139] FIG. 18B is a schematic cross-sectional view taken along a line B-B of FIG. 17 according to an exemplary modality.
[0140] [0140] FIG. 18C is a schematic cross-sectional view taken along a line C-C of FIG. 17 according to an exemplary modality.
[0141] [0141] FIG. 18D is a schematic cross-sectional view taken along a D-D line of FIG. 17 according to an exemplary modality.
[0142] [0142] FIGS. 19A, 19B, 20A, 20B, 21A, 21B, 21C, 22A, 22B, 22C, 23A, 23B, 24A, 24B, 25A, 25B, 26A, 26B, 27B, 27A, 27B, 28A, 28B, 29A, 29B, 30A, 30B, 31, 32A, 32B and 33 are schematic plan views and cross-sectional views illustrating a method of manufacturing a display device according to an exemplary embodiment.
[0143] [0143] FIG. 34 is a schematic cross-sectional view illustrating a display device in accordance with yet another exemplary embodiment.
[0144] [0144] FIG. 35 is a schematic circuit diagram of a display device in accordance with yet another exemplary embodiment.
[0145] [0145] FIG. 36 is a schematic cross-sectional view of a stack of LEDs for a display in accordance with an exemplary embodiment.
[0146] [0146] FIGS. 37A, 37B, 37C, 37D and 37E are schematic cross-sectional views that illustrate a method of manufacturing a stack of light-emitting diodes for a display according to an exemplary embodiment.
[0147] [0147] FIG. 38 is a schematic circuit diagram of a display device according to an exemplary embodiment.
[0148] [0148] FIG. 39 is a schematic plan view of a display device according to an exemplary embodiment.
[0149] [0149] FIG. 40 is an enlarged one-pixel plan view of the display device of FIG. 39 according to an exemplary modality.
[0150] [0150] FIG. 41 is a schematic cross-sectional view taken along a line A-A of FIG. 40.
[0151] [0151] FIG. 42 is a schematic cross-sectional view taken along a line B-B of FIG. 40.
[0152] [0152] FIGS. 43A, 43B, 43C, 43D, 43E, 43F, 43G, 43H, 43I, 43J and 43K are schematic views of the plan illustrating a method of manufacturing a display device according to an exemplary embodiment.
[0153] [0153] FIG. 44 is a schematic circuit diagram of a display device according to another exemplary embodiment.
[0154] [0154] FIG. 45 is a schematic plan view of a display device according to another exemplary embodiment.
[0155] [0155] FIG. 46 is a schematic cross-sectional view of a stack of LEDs for a display in accordance with an exemplary embodiment.
[0156] [0156] FIGS. 47A, 47B, 47C, 47D and 47E are schematic cross-sectional views that illustrate a method of manufacturing a stack of light-emitting diodes for a display according to an exemplary modality.
[0157] [0157] FIG. 48 is a schematic circuit diagram of a display device according to an exemplary embodiment.
[0158] [0158] FIG. 49 is a schematic plan view of a display device according to an exemplary embodiment.
[0159] [0159] FIG. 50 is an enlarged one-pixel plan view of the display device of FIG. 49 according to an exemplary modality.
[0160] [0160] FIG. 51 is a schematic cross-sectional view taken along a line A-A of FIG. 50 according to an exemplary modality.
[0161] [0161] FIG. 52 is a schematic cross-sectional view taken along a line B-B of FIG. 50 according to an exemplary modality.
[0162] [0162] FIGS. 53A, 53B, 53C, 53D, 53E, 53F, 53G, 53H, 53I, 53J and 53K are schematic views of the plan illustrating a method of manufacturing a display device according to an exemplary embodiment.
[0163] [0163] FIG. 54 is a schematic circuit diagram of a display device according to another exemplary embodiment.
[0164] [0164] FIG. 55 is a schematic plan view of a display device according to another exemplary embodiment.
[0165] [0165] FIG. 56 is a schematic plan view of a display device according to an exemplary embodiment.
[0166] [0166] FIG. 57 is a schematic cross-sectional view of a LED pixel for a display in accordance with an exemplary embodiment.
[0167] [0167] FIG. 58 is a schematic circuit diagram of a display device according to an exemplary embodiment.
[0168] [0168] FIG. 59A and FIG. 59B are a top view and a bottom view of a pixel of a display device according to exemplary embodiments, respectively.
[0169] [0169] FIG. 60A is a schematic cross-sectional view taken along a line A-A of FIG. 59A.
[0170] [0170] FIG. 60B is a schematic cross-sectional view taken along a line B-B of FIG. 59A according to an exemplary embodiment.
[0171] [0171] FIG. 60C is a schematic cross-sectional view taken along a line C-C of FIG. 59A according to an exemplary embodiment.
[0172] [0172] FIG. 60D is a schematic cross-sectional view taken along a D-D line of FIG. 59A according to an exemplary embodiment.
[0173] [0173] FIGS. 61A, 61B, 62A, 62B, 63A, 63B, 64A, 64B, 65A, 65B, 66A, 66B, 67A, 67B, 68A and 68B are schematic plan views and cross-sectional views illustrating a method of manufacturing a exhibition according to an exemplary modality.
[0174] [0174] FIG. 69 is a cross-sectional view of a pixel of LED light for a display according to an exemplary embodiment.
[0175] [0175] FIG. 70 is an enlarged one-pixel view of a display device according to an exemplary embodiment.
[0176] [0176] FIG. 71A and FIG. 71B are seen in cross section taken along lines G-G and H-H of FIG. 70, respectively.
[0177] [0177] 【Mode for Invention】
[0178] [0178] In the following description, for the purpose of explanation, several specific details are presented, in order to provide a complete understanding of various exemplary modalities 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.
[0179] [0179] Unless otherwise specified, the illustrated exemplary modalities 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.
[0180] [0180] 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.
[0181] [0181] When an element such as one or layer is referred to as being "above", "connected to" or "attached to" or another element or layer, it can be directly on, connected to or attached 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.
[0182] [0182] 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.
[0183] [0183] 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.
[0184] [0184] 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, operations, elements, components and / or groups, but it does not exclude the presence or addition of one or more features, whole numbers,
[0185] [0185] 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.
[0186] [0186] 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 a 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.
[0187] [0187] As used herein, a stack of light-emitting diodes or a light-emitting diode according to exemplary modalities may include a micro LED, which has a surface area of less than about 10,000 µm square, as known in the art. In other exemplary embodiments, micro LEDs can have a surface area of less than about
[0188] [0188] Referring to FIG. 1, the stack of light-emitting diodes 100 for a display may include a support substrate 51, a first stack of LED 23, a second stack of LED 33, a third stack of LED 43, a first reflective electrode p 25, a second transparent electrode p 35, a third transparent electrode p 45, a first color filter 37, a second color filter 47, a first connection layer 53, a second connection layer 55 and a third connection layer 57. As used for the exemplary modalities disclosed here, a stack of light emitting diodes can refer to a micro LED (or a stack of micro LED).
[0189] [0189] The support substrate 51 supports the first, second and third LED semiconductor batteries 23, 33 and 43. The support substrate 51 can have a circuit on a surface or an internal part of it, but the inventive concepts are not limited to these. The support substrate 51 can include, for example, a Si substrate or a Ge substrate.
[0190] [0190] The first LED stack 23, the second LED stack 33 and the third LED stack 43 include a n-type semiconductor layer, a p-type semiconductor layer and an active layer interposed between them. The active layer can have a multi-quantum well structure.
[0191] [0191] For example, the first battery of LED 23 can be an inorganic light-emitting diode that emits red light, the second battery of LED 33 can be an inorganic light-emitting diode that emits green light and the third battery of LED 43 it can be an inorganic LED that 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 limited to these, and when the stack of light emitting diodes 100 includes micro LEDs, the first stack of LED 23 can emit any one of red, green and blue light, and the second and third batteries of LEDs 33 and 43 can emit a light different from the red, green and blue lights without adversely affecting the operation or requiring color filters due to their small form factor.
[0192] [0192] The top and bottom surfaces of each of the first, second and third LED batteries 23, 33 or 43 may include a n-type semiconductor layer and a p-type semiconductor layer, respectively. In FIG. 1, an upper surface of each of the first to third LED cells 23, 33 and 43 is described as including a n-type semiconductor layer and a lower surface is described as including a p-type semiconductor layer. Since the top surface of the third stack of LED 43 is of type n, a rough surface can be formed on the top surface of the third stack of LED 43 through chemical engraving. However, the inventive concepts are not limited to these, and the semiconductor type of the upper and lower surfaces of each LED battery can be reversed.
[0193] [0193] The first battery of LED 23 is disposed closer to the support substrate 51, the second battery of LED 33 is disposed in the first battery of LED 23 and the third battery of LED 43 is disposed in the second battery of LED 33. One Since the first battery of LED 23 emits light with a wavelength longer than the second and third batteries of LED 33 and 43, the light generated in the first battery of LED 23 can be transmitted through the second and third batteries of LED 33 and 43 and issued abroad. In addition, since the second battery of LED 33 emits light with a wavelength greater than the third battery of LED 43, the light generated in the second battery of LED 33 can be transmitted through the third battery of LED 43 and emitted to the outside.
[0194] [0194] The first reflective electrode p 25 is in ohmic contact with the semiconductor type p layer of the first LED stack 23 and can reflect the light generated from the first LED stack 23. For example, the first reflective electrode 25 can include Au-Ti, Au-Sn or the like. In addition, the first reflective electrode 25 may include a diffusion barrier layer.
[0195] [0195] The second transparent p 35 electrode is in ohmic contact with the type p semiconductor layer of the second 33 LED stack. The second transparent p 35 electrode can include a metal layer or a conductive oxide layer, which is transparent to red light and green light.
[0196] [0196] The third transparent p 45 electrode is in ohmic contact with the type p semiconductor layer of the third 33 LED stack. The third transparent p 45 electrode can include a metal layer or a conductive oxide layer, which is transparent to red light, green light and blue light.
[0197] [0197] The first reflective electrode p 25, the second transparent electrode 35 and the third transparent electrode 45 are in ohmic contact with the p-type semiconductor layer of each LED stack 23, 33 and 43 and can help spread current.
[0198] [0198] Meanwhile, the first color filter 37 can be disposed between the first stack of LED 23 and the second stack of LED 33. In addition, the second color filter 47 can be disposed between the second stack of LED 33 and the third LED stack 43. The first color filter 37 transmits light generated in the first LED stack 23 and reflects the light generated in the second LED stack 33. Meanwhile, the second color filter 47 transmits light generated in the first and the second LED battery 23 and 33 and reflects the light generated in the third LED battery 43. Thus, the light generated in the first LED battery 23 can be emitted to the outside through the second LED battery 33 and the third LED battery 43 and the light generated in the second battery of LED 33 can be emitted outwards through the third battery of LED 43. In addition, the light generated in the second battery of LED 33 can be prevented from being incident in the first battery of LED 23 to be lost, and the light generated in the third stack of LED 43 can be prevented from shining the second 33 LED battery to be lost. According to an exemplary modality, the first color filter 37 can also reflect the light generated in the third LED stack 43.
[0199] [0199] Each of the first and second color filters 37 and 47 can be, for example, a low pass filter that passes through only a low frequency region (for example, a long wavelength region), a filter bandwidth that passes through only a predetermined wavelength range, or a bandwidth filter that blocks only a predetermined wavelength range.
[0200] [0200] The first connection layer 53 couples the first LED stack 23 to the support substrate 51. As shown in Fig. 1, the first reflective electrode p 25 can be in contact with the first connection layer 53. The first layer connection layer 53 may be a transmissive or light-opaque layer. The first bonding layer 53 can be, for example, a transparent inorganic insulating film, a transparent organic insulating film or a thin transparent conductive film.
[0201] [0201] The second connection layer 55 couples the second battery of LED 33 to the first battery of LED 23. As shown in Fig. 1, the second connection layer 55 can be in contact with the first battery of LED 23 and the first color filter 37. However, the inventive concepts are not limited to these, and a transparent conductive layer can be additionally arranged in the first LED stack 23. The second link layer 55 transmits light generated in the first LED stack 23. A the second bonding layer 55 can be, for example, a transparent inorganic insulating film, a transparent organic insulating film or a thin transparent conductive film, and can be formed, for example, by light transmissive spin-on-glass.
[0202] [0202] The third connection layer 57 couples the third battery of LED 43 to the second battery of LED 33. As shown in Fig. 1, the third connection layer 57 can be in contact with the second battery of LED 33 and the second color filter 47. However, the inventive concepts are not limited to them, and a transparent conductive layer can be additionally arranged in the second LED stack 33. The third link layer 57 transmits light generated in the first LED stack 23 and in the second LED stack 33. The third connection layer 57 can be, for example, a transparent inorganic insulating film, a transparent organic insulating film or a thin transparent conductive film, and can be formed, for example, by spin-on-glass transmissive to light.
[0203] [0203] FIG. 2 is a schematic cross-sectional view illustrating a method of manufacturing a stack of light-emitting diodes for a display according to an exemplary embodiment.
[0204] [0204] Referring to FIG. 2, first, the first LED stack 23 is grown on a first substrate 21 and a first reflective electrode p 25 is formed on the first LED stack 23.
[0205] [0205] The first substrate 21 can be, for example, a GaAs substrate. In addition, the first LED stack 23 is formed as semiconductor layers based on AlGaInP and includes an n-type semiconductor layer, an active layer and a p-type semiconductor layer. The first reflective electrode p 25 is in ohmic contact with the p-type semiconductor layer of the first LED stack 23.
[0206] [0206] Meanwhile, a second stack of LED 33 is grown on a second substrate 31, and a second transparent electrode p 35 and a first color filter 37 are formed on the second stack of LED 33. The second stack of LED 33 is formed by semiconductor layers based on gallium nitride and may include a GaInN well layer. The second substrate 31 is a substrate in which the semiconductor layer based on gallium nitride can be grown and is different from the first substrate 21. A proportion of GaInN composition can be determined so that the second LED stack 33 emits light green. The second transparent electrode p 35 is in ohmic contact with the p-type semiconductor layer of the second LED stack 33.
[0207] [0207] In addition, a third stack of LED 43 is grown on a third substrate 41 and a third transparent electrode p 45 and a second color filter 47 are formed on the third stack of LED 43. The third stack of LED 43 is formed by semiconductor layers based on gallium nitride and may include a GaInN well layer. The third substrate 41 is a substrate, in which the semiconductor layer based on gallium nitride can be grown and is different from the first substrate 21. A proportion of GaInN composition can be determined so that the third LED stack 43 emits light blue. Meanwhile, the third transparent p 45 electrode is in ohmic contact with the p-type semiconductor layer of the third LED stack 43.
[0208] [0208] The first color filter 37 and the second color filter 47 of FIG. 2 are the same as those described with reference to FIG. 1 and, therefore, detailed descriptions will be omitted to avoid redundancy.
[0209] [0209] Referring to FIGS. 1 and 2, the first LED stack 23 is connected to the support substrate 51 through the first connection layer 53. The first connection layer 53 can be disposed in advance on the support substrate 51 and the first reflective electrode p 25 can be connected to the first bonding layer 53 and facing support substrate 51. Meanwhile, the first substrate 21 is removed from the first stack of LED 23 using a chemical etching technique.
[0210] [0210] Then, the second stack of LED 33 is connected to the first stack of LED 23 through the second link layer 55. The first color filter 37 is connected to the second link layer 55 and faces the first stack of LED 23. The second link layer 55 can be arranged on the first stack of LED 23 in advance, and the first color filter 37 can be arranged to face and connected to the second link layer 55. Meanwhile, the second substrate 31 can be separated from the second battery of LED 33, using techniques such as laser lifting, chemical lifting and the like.
[0211] [0211] Then, the third stack of LED 43 is connected to the second stack of LED 33 through the third link layer 57. The first color filter 47 is linked to the third link layer 57 and faces the second stack of LED 33. The third link layer 57 can be arranged on the second stack of LED 33 in advance, and the first color filter 47 can be arranged to face and connected to the third link layer 57. Meanwhile, the third substrate 41 can be separated from the third stack of LED 43, using techniques such as laser lifting, chemical lifting and the like. In this way, a stack of light-emitting diodes for a display shown in FIG. 1 is formed, in which the n-type semiconductor layer of the third LED stack 43 is exposed.
[0212] [0212] A display device, according to an exemplary modality, can be formed by standardizing the stack of the first to third LED cells 23, 33 and 43 arranged on the support substrate 51 in pixel units and connecting these LED cells to each other. to others through interconnections. Next, a display device, according to an exemplary modality, will be described.
[0213] [0213] FIG. 3 is a schematic circuit diagram of a display device according to an exemplary embodiment. FIG. 4 is a schematic plan view of a display device according to an exemplary embodiment. FIG. 5 is an enlarged plan view of a pixel region of the display device of FIG. 4 according to an exemplary modality. FIG. 6 is a schematic cross-sectional view taken along a line A-A of FIG. 5, and FIG. 7 is a schematic cross-sectional view taken along a line B-B of FIG. 5.
[0214] [0214] Referring to FIGS. 3 and 4, the display device according to the exemplary modality can be implemented to be activated in a passive matrix manner.
[0215] [0215] For example, the stack of light emitting diodes for a display described with reference to FIG. 1 has a structure, in which the first to the third LED batteries 23, 33 and 43 are stacked in the vertical direction and therefore a pixel includes three light emitting diodes R, G and B. Here, the first light emitting diode R corresponds to the first LED battery 23, the second LED G corresponds to the second LED battery 33 and the third LED B corresponds to the third LED battery 43.
[0216] [0216] In FIGS. 3 and 4, a pixel includes the first to the third light emitting diodes R, G and B, and each light emitting diode corresponds to a subpixel. The anodes of the first to the third light emitting diodes R, G and B are connected to a common line (for example, a data line), and the cathodes of the same are connected to different lines (for example, scanning lines). More particularly, in a first pixel, the anodes from the first to the third light-emitting diodes R, G and B are connected in common to the data line Vdata1, and their cathodes are connected to the scan lines Vscan1-1, Vscan1- 2 and Vscan1 -3, respectively. Thus, the light emitting diodes R, G and B in the same pixel can be activated independently.
[0217] [0217] In addition, each of the light emitting diodes R, G and B can be activated in a pulse width modulation scheme or by changing the current intensity, thus adjusting the luminance of each subpixel.
[0218] [0218] Referring to FIG. 4, a plurality of pixels are formed by standardizing the LED stacks described with reference to FIG. 1, and each of the pixels is connected to the first reflecting electrodes 25 and to the interconnecting lines 71, 73 and 75. As shown in Fig. 3, the first reflecting electrode p 25 can be used as the Vdata data line and the lines interconnect 71, 73 and 75 can be used as the scan lines.
[0219] [0219] The pixels can be arranged in a matrix form, the anodes of the light-emitting diodes R, G and B of each pixel are connected in common to the first reflective electrode p 25, and their cathodes are connected to the interconnection lines 71, 73 and 75, respectively, which are spaced from each other. Interconnect lines 71, 73 and 75 can be used as a Vscan scan line.
[0220] [0220] Referring to FIGS. 4 to 7, a portion of the first reflective electrode p 25, a portion of the upper surface of the first LED stack 23, a portion of the second transparent electrode of p 35, a portion of the upper surface of the second LED stack 33, a portion of the third transparent electrode p 45 and the upper surface of the third stack of LED 43 in each pixel are exposed to the outside.
[0221] [0221] The third LED stack 43 may have a rough surface 43a on its upper surface. The rough surface 43a can be formed across the top surface of the third LED stack 43 or it can be formed in a part of it, as shown in FIG. 6.
[0222] [0222] The first insulation layer 61 can cover a lateral surface of each pixel. The first insulation layer 61 can be formed from a light transmitting material such as SiO2. In this case, the first insulation layer 61 can cover the entire upper surface of the third stack of LED 43. Alternatively, the first insulation layer 61 can include a distributed Bragg reflector to reflect the light traveling towards the side surface on the first to the third LED battery 23, 33 and 43. In this case, the first insulation layer 61 exposes at least partially the upper surface of the third LED battery 43.
[0223] [0223] The first insulation layer 61 can have an opening 61a exposing the top surface of the third LED stack 43, an opening 61b exposing the top surface of the second LED stack 33, an opening 61c (well shown in FIG. 8H) exposing the top surface of the first LED stack 23 and an opening 61d exposing the third transparent electrode p 45, an opening 61e exposing the second transparent electrode p 35 and openings 61f exposing the first reflective electrode p 25.
[0224] [0224] Interconnect line 71 and interconnect line 75 can be formed on support substrate 51 in the vicinity of the first to third LED stacks 23, 33 and 43 and can be arranged on the first insulation layer 61 to be isolated from the first electrode p 25. Meanwhile, a connector 77a connects the third transparent electrode p 45 to the first reflective electrode 25, a connector 77b connects the second transparent electrode 35 to the first reflective electrode 25 and the anodes of the first LED stack 23, the second LED battery 33 and the third LED battery 43 are connected in common to the first reflective electrode p 25.
[0225] [0225] Meanwhile, a connector 71a connects the top surface of the third LED stack 43 to the interconnect line 71 and a connector 75a connects the top surface of the first LED stack 23 to the interconnect line 75.
[0226] [0226] The second insulation layer 81 is arranged on the interconnect lines 71 and 73 and the first insulation layer 61 and can cover the top surface of the third LED stack 43. The second insulation layer 81 can have an opening 81a that exposes a portion of the top surface of the second LED stack 33.
[0227] [0227] Interconnect line 73 can be arranged on the second insulation layer 81, and a connector 73a can connect the top surface of the second LED stack 33 to interconnect line 73. Connector 73a can pass over the top of the line interconnect 75 and is isolated from interconnect line 75 by the second insulation layer 81.
[0228] [0228] As described above, the electrodes of each pixel, according to an exemplary modality, can be connected to the data lines and the scan lines. In particular, FIGS. 4-7 show that interconnect lines 71 and 75 are formed in the first insulation layer 61 and interconnect line 73 is formed in the second insulation layer 81, however, the inventive concepts are not limited to it. For example, each of the interconnect lines 71, 73 and 75 can be formed in the first insulation layer 61 and covered with the second insulation layer 81 and the second insulation layer 81 can have an opening that exposes the interconnect line 73 In this case, connector 73a can connect the top surface of the second stack of LED 33 to the interconnect line 73 through the openings of the second insulation layer 81.
[0229] [0229] Meanwhile, interconnect lines 71, 73 and 75 can be formed on the support substrate 51 and connectors 71a, 73a and 75a can connect the upper surfaces of the first to the third LED batteries 23, 33 and 43 to the lines of interconnection 71, 73 and 75 in the first insulation layer 61.
[0230] [0230] FIGS. 8A to 8K are schematic plan views that illustrate a method of manufacturing a display device according to an exemplary embodiment.
[0231] [0231] First, a stack of light emitting diodes 100 shown in FIG. 1 is provided.
[0232] [0232] Next, with reference to FIG. 8A, a rough surface 43a can be formed on the top surface of the third LED stack 43. The rough surface 43a can be formed to correspond to each pixel region on the top surface of the third LED stack 43. The rough surface 43a can be formed by a chemical engraving technique, for example, by a photo-enhanced chemical engraving technique (PEC).
[0233] [0233] The rough surface 43a can be partially formed within each pixel region, considering the region of the third LED stack 43 to be further recorded, but the inventive concepts are not limited to this and can be formed across the entire surface top of the third LED stack 43.
[0234] [0234] Referring to FIG. 8B, a peripheral region of the third LED stack 43 is then recorded in each pixel region to expose the third transparent electrode p 45. The remaining third LED stack 43 can be rectangular or square in shape and a plurality of depression parts can be be formed along its edges.
[0235] [0235] Referring to FIG. 8C, the exposed third transparent electrode p 45 is then removed, except for a part of it that corresponds to a depression part formed in the third LED stack 43, to expose the top surface of the second LED stack 33. The top surface of the the second battery of LED 33 is exposed around the third battery of LED 43 and in other depression parts of the third battery of LED 43, except the one in which the third transparent electrode p 45 remains.
[0236] [0236] Referring to FIG. 8D, the second exposed LED battery 33 is removed, except for a part of it that corresponds to another depression part of the third LED battery 43, in order to expose the second transparent electrode p 35.
[0237] [0237] Referring to FIG. 8E, the exposed second transparent electrode p 35 is then removed, except for a part of it that corresponds to another depression part of the third LED stack 43 to expose the top surface of the first LED stack 23. Thus, the top surface of the the first LED stack 23 is exposed around the third LED stack 43 and the top surface of the first LED stack 23 is also exposed to at least one of the depression parts of the third LED stack 43.
[0238] [0238] Referring to FIG. 8F, the first exposed LED battery 23 is removed, except for a part of it that corresponds to another depression part of the third LED battery 43, to expose the first reflective electrode p 25. The first reflective electrode p 25 is exposed in around the third stack of LED 43.
[0239] [0239] Referring to FIG. 8G, the first reflective electrode 25 is standardized to form lines of linear interconnection, so that support substrate 51 can be exposed. The first reflective electrode p 25 can connect the pixels arranged in a column to each other, as shown in FIG. 4.
[0240] [0240] Referring to FIG. 8H, a first insulating layer (61 in FIGS. 6 and 7) is formed to cover the pixel. In particular, the first insulation layer 61 covers the side surfaces of the first to the third LED batteries 23, 33 and 43 while covering the first reflective electrode p 25. In addition, the first insulation layer 61 can at least partially cover the surface top of the third LED stack 43. When the first insulation layer 61 is a transparent layer, such as SiO2, the first insulation layer 61 can cover the entire top surface of the third LED stack 43. Alternatively, when the first insulation layer 61 includes a distributed Bragg reflector, the first insulating layer 61 can expose at least a portion of the upper surface of the third LED stack 43, so that the light is emitted to the outside.
[0241] [0241] Meanwhile, the first insulation layer 61 may include an opening 61a exposing the third LED stack 43, an opening 61b exposing the second LED stack 33, an opening 61c exposing the first LED stack 23, an opening 61d exposing the third transparent electrode 45, an opening 61e exposing the second transparent electrode p 35 and an opening 61f exposing the first reflective electrode p 25. At least two openings 61f that expose the first reflective electrode 25 can be formed.
[0242] [0242] Referring to FIG. 8I, interconnect lines 71 and 75 and connectors 71a, 75a, 77a and 77b are then formed using a lifting technique or the like. Interconnect lines 71 and 75 are isolated from the first reflective electrode 25 by the first insulation layer 61. Connector 71a electrically connects the third LED stack 43 to interconnect line 71 and connector 75a electrically connects the first LED stack 23 to the interconnect line 75. Meanwhile, connector 77a electrically connects the third transparent electrode p 45 to the first reflective electrode p 25 and connector 77b electrically connects the second transparent electrode p 35 to the first reflective electrode p 25.
[0243] [0243] Referring to FIG. 8J, a second insulation layer (81 in FIG. 6 and FIG. 7) then covers interconnect lines 71 and 75 and connectors 71a, 75a, 77a and 77b. The second insulation layer 81 can also cover the entire top surface of the third LED stack 43. Meanwhile, the second insulation layer 81 has an opening 81a that exposes the top surface of the second LED stack 33. The second insulation layer 81 may be formed, for example, by a silicon oxide film or a silicon nitride film, and may also include a distributed Bragg reflector. When the second insulation layer 81 includes a distributed Bragg reflector, the second insulation layer 81 can at least partially expose the upper surface of the third LED stack 43 to emit light to the outside.
[0244] [0244] Referring to FIG. 8K, interconnect line 73 and connector 73a are then formed by a lifting technique or the like. Interconnect line 73 is arranged in the second insulation layer 81 and is isolated from the first reflective electrode p 25 and interconnect lines 71 and 75. Connector 73a electrically connects the second battery of LED 33 and interconnect line 73. O connector 73a can traverse an upper part of interconnect line 75 and is isolated from interconnect line 75 by the second insulating layer 81.
[0245] [0245] In this way, a pixel region shown in FIG. 5 can be formed. In addition, as shown in Fig. 4, the plurality of pixels can be formed on the support substrate 51, and these pixels can be connected to each other by the first reflective electrode 25 and by the interconnecting lines 71, 73 and 75, so to be activated in the form of a passive matrix.
[0246] [0246] As described above, a method of manufacturing a passively powered display device has been described according to an exemplary embodiment. However, the inventive concepts are not limited to the specific manufacturing method described above, and a display device to be operated in a passive matrix manner can be manufactured in several ways, using the stack of light-emitting diodes shown in FIG. 1. For example, interconnect line 73 has been described as being formed in the second insulation layer 81, but interconnect line 73 can be formed in the first insulation layer 61 together with interconnect lines 71 and 75 and connector 73a it can be formed in the second insulation layer 81 to connect the second stack of LED 33 to the interconnect line 73. In addition, the interconnect lines 71, 73 and 75 can be provided on the support substrate 51.
[0247] [0247] FIG. 9 is a schematic circuit diagram of a display device according to another exemplary embodiment. Although the display device described with reference to FIGS. 3-8 is configured to be activated in a passive matrix, the display device according to the illustrated mode is for activating the active matrix.
[0248] [0248] Referring to FIG. 9, a drive circuit according to an exemplary embodiment includes two or more transistors Tr1 and Tr2 and a capacitor. When the power supply is connected to the selection lines Vrow1 to Vrow3 and a data voltage is applied to the data lines Vdata1 to Vdata3, a voltage is applied to the corresponding LED. In addition, the charges are charged to the corresponding capacitor according to the values of Vdata1 and Vdata3. The transistor Tr2 can maintain an activation state by the charged voltage of the capacitor and thus, even when the power supply is cut off in the selection line Vrow1, the voltage of the capacitor can be maintained and the voltage can be applied to the light emitting diodes LED1 to LED3. In addition, the currents that flow through LED1 to LED3 can be changed according to the values from Vdata1 to Vdata3. As the current can always be supplied by Vdd, the light can be emitted continuously.
[0249] [0249] Transistors Tr1 and Tr2 and capacitor can be formed on a support substrate 51. For example, a thin film transistor formed on a silicon substrate can be used for active activation of the matrix.
[0250] [0250] The light emitting diodes LED1, LED and LED3 can correspond to the first, second and third LED batteries 23, 33 and 43 stacked in one pixel. The anodes of the first to the third LED batteries 23, 33 and 43 can be connected to transistor Tr2 and their cathodes can be grounded.
[0251] [0251] While FIG. 9 shows a drive circuit of a display device for active drive of the matrix, the inventive concepts are not limited to this and other circuits can be used. In addition, while the anodes of the light emitting diodes LED1 to LED3 are described as being connected to the different transistors Tr2 and their cathodes are grounded, alternatively, the anodes of the light emitting diodes can be connected to the current supply Vdd and their cathodes can be connected to different transistors.
[0252] [0252] FIG. 10 is a schematic plan view of a display device in accordance with yet another exemplary embodiment. In the following, a pixel of the plurality of pixels disposed on the support substrate 151 will be described.
[0253] [0253] Referring to FIG. 10, the pixel according to an exemplary embodiment is generally similar to the pixel described with reference to FIGS. 4 to 7, except that the support substrate 151 is a thin film transistor panel, including a transistor and a capacitor, and the first reflector electrode 25 is defined within a lower region of the first LED stack
[0254] [0254] The cathode of the third LED stack 43 is connected to the support substrate 151 through connector 171a. For example, as shown in FIG. 9, the cathode of the third LED stack 43 (e.g., LED 3) can be electrically connected to the support substrate 151 and grounded. The cathodes of the second LED stack 33 (for example, LED 2) and the first LED stack 23 (for example, LED 1) can also be connected to the support substrate 151 via connectors 173a and 175a and are grounded, respectively.
[0255] [0255] Meanwhile, the first reflective electrode 25 is connected to a transistor (Tr2 in FIG. 9) provided on the support substrate 151. The third transparent electrode p 45 and the second transparent electrode p 35 are also connected to the transistor (Tr2 in Fig. 9) provided on support substrate 151 through connectors 171b and 173b, respectively.
[0256] [0256] When connecting the first to the third battery of LEDs 23, 33 and 43, as described above, a circuit for active activation of the matrix, as shown in FIG. 9 can be built.
[0257] [0257] While FIG. 10 shows a pixel of a display device for active activation of the matrix, the inventive concepts are not limited to this and several modifications can be made in various circuits for active activation of the matrix.
[0258] [0258] Meanwhile, returning to FIG. 1, the first reflective electrode p 25, the second transparent electrode p 35 and the third transparent electrode p 45 are described as being in ohmic contact with the type p semiconductor layers of the first LED stack 23, the second LED stack 33 and the third stack of LED 43, respectively, but the ohmic contact layer is not supplied separately in the type n semiconductor layers. This is because when a pixel size is as small as 200 micrometers or less, there is less difficulty in propagating the current, even without forming a separate ohmic contact layer in the n-type semiconductor layer. However, for current propagation, the transparent electrode layers can still be arranged in the n-type semiconductor layer of each LED cell, if necessary.
[0259] [0259] The first to third LED batteries 23, 33 and 43 can be connected together by various configurations.
[0260] [0260] FIG. 11 is a schematic cross-sectional view of a light emitting diode stack for a display in accordance with yet another exemplary embodiment.
[0261] [0261] Referring to FIG. 11, the light emitting diode stack 101 may include the supporting substrate 51, the first LED stack 23, the second LED stack 33, the third LED stack 43, the second transparent electrode p 35, the third transparent electrode p 45, the first color filter 137, the second color filter 47, a first connection layer 153, a second connection layer 155 and a third connection layer 157, similarly to the light emitting diode stack 100 of FIG. 1. The stack of light-emitting diodes 101 may further include a first reflective electrode no 129, a first transparent electrode p 125 and a second transparent electrode no
[0262] [0262] The support substrate 51 supports the semiconductor stacks 23, 33 and 43. The support substrate 51 may have a circuit on a surface or an internal part of it, but the inventive concepts are not limited to these. The support substrate 51 can include, for example, a Si substrate or a Ge substrate.
[0263] [0263] The first battery of LED 23, the second battery of LED 33 and the third battery of LED 43 are similar to those described with reference to FIG. 1 and therefore detailed descriptions will be omitted to avoid redundancy. The stack of light-emitting diodes 101 is different from FIG. 1, where the bottom surfaces of the first LED stack 23 and the second LED stack 33 are type n and the top surfaces are type p. The bottom surface of the third LED stack 43 is of type p and the top surface of it is of type n, which is substantially the same as that of FIG. 1.
[0264] [0264] Since the top surface of the first LED 23 battery is of type p, the first transparent electrode p 125 is in ohmic contact with the upper surface of the first LED battery 23. The first transparent electrode p 125 transmits generated light in the first stack of LED 23, for example, red light.
[0265] [0265] The first reflective electrode 129 is in ohmic contact with the bottom surface of the first LED battery 23. The first reflective electrode n 129 is in ohmic contact with the first LED battery 23 and reflects the light generated in the first LED battery 23. The first reflective electrode No. 129 can be formed, for example, by Au-Ti, Au-Sn or the like. In addition, the first reflective electrode 129 may include a diffusion barrier layer.
[0266] [0266] The second transparent electrode p 35 is in ohmic contact with the semiconductor type p of the second cell of LED 33. As the upper surface of the second cell of LED 33 is of type p, the second transparent electrode p 35 is arranged on the second battery of LED 33. The second transparent electrode p 35 can be formed by a layer of metal or a layer of conductive oxide, which is transparent to red light and green light.
[0267] [0267] The second transparent electrode n 139 is in ohmic contact with the bottom surface of the second battery of LED 33. The second transparent electrode n 139 can also be formed of a metal layer or a layer of conductive oxide, which is transparent to red light and green light. The second transparent electrode n 139 is partially exposed by standardizing the second battery of LED 33 to provide a connection terminal for electrical connection to the type n semiconductor layer of the second battery of LED 33.
[0268] [0268] The third p 45 transparent electrode is in ohmic contact with the p type semiconductor layer of the third 33 LED stack. The third p 45 transparent electrode can be formed by a metal layer or a conductive oxide layer, which is transparent to red light, green light and blue light.
[0269] [0269] The first color filter 137 is disposed between the first battery of LED 23 and the second battery of LED 33. In addition, the second color filter 47 is disposed between the second battery of LED 33 and the third battery of LED 43. The first color filter 137 transmits light generated in the first LED battery 23 and reflects the light generated in the second LED battery 33. The second color filter 47 transmits light generated in the first and second LED batteries 23 and 33 and reflects the light generated in the third battery of LED 43. Thus, the light generated in the first battery of LED 23 can be emitted to the outside through the second battery of LED 33 and the third battery of LED 43 and the light generated in the second battery of LEDs. LED 33 can be emitted to the outside through the third battery of LED 43. In addition, it is possible to prevent the light generated in the second battery of LED 33 from being incident in the first battery of LED 23 to be lost, or the light generated in the third LED battery 43 is incident on the second LED battery 33 to be lost.
[0270] [0270] According to some exemplary modalities, the first color filter 137 can reflect the light generated in the third LED stack 43.
[0271] [0271] Each of the first and second color filters 137 and 47 can be, for example, a low pass filter that passes through only a low frequency region, that is, a long wavelength region, a bandwidth that passes through only a predetermined wavelength range, or a band interrupt filter that blocks only the predetermined wavelength range. In particular, the first and second color filters 137 and 47 can be the band interrupt filter, including a distributed Bragg reflector (DBR). The distributed Bragg reflector can be formed by alternately stacking insulating layers with different refractive indices, for example, by alternately stacking TiO2 and SiO2. In addition, the 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.
[0272] [0272] The first connection layer 153 couples the first LED stack 23 to the support substrate 51. As shown in Fig. 11, the first reflective electrode no 129 may be in contact with the first connection layer 153. The first layer connector 153 can be light transmitting or opaque. The first bonding layer 153 can be, for example, a transparent inorganic insulating film, a transparent organic insulating film or a thin transparent conductive film.
[0273] [0273] The second connection layer 155 couples the second battery of LED 33 to the first battery of LED 23. As shown in Fig. 11, the second connection layer 155 can be arranged on the first color filter 137 and can be in contact with the second transparent electrode n 139. The second connection layer 155 transmits light generated in the first LED stack 23. The second connection layer 155 can be, for example, a transparent inorganic insulating film, a transparent organic insulating film or a film thin transparent conductor, and can be formed, for example, by light transmissive spin-on-glass.
[0274] [0274] The third connection layer 157 couples the third battery of LED 43 to the second battery of LED 33. As shown in Fig. 11, the third connection layer 157 can be in contact with the second transparent electrode p 35 and in contact with the second color filter 47. The third link layer 157 transmits light generated in the first LED stack 23 and the second LED stack 33. The third link layer 157 can be, for example, a transparent inorganic insulating film, a transparent organic insulating film or a thin transparent conductive film, and can be formed, for example, by light transmissive spin-on-glass.
[0275] [0275] FIGS. 12A to 12F are schematic cross-sectional views illustrating a method of manufacturing a stack of light-emitting diodes for a display in accordance with yet another exemplary embodiment.
[0276] [0276] Referring to FIG. 12A, the third LED stack 43 is grown on the third substrate 41, and the third transparent electrode p 45 and the second color filter 47 are formed on the third LED stack 43. The third LED stack 43 can be formed by semiconductor layers based on gallium nitride and may include a layer of GaInN well. The third substrate 41 is a substrate on which the semiconductor layer based on gallium nitride can be grown, for example, a sapphire substrate. A ratio of GaInN composition can be determined so that the third LED stack 43 emits blue light. The third transparent electrode p 45 is in ohmic contact with the type p semiconductor layer of the third battery of LED 43.
[0277] [0277] Referring to FIG. 12B, the second stack of LED 33 is grown on a second substrate 31, and the second transparent electrode p 35 is formed on the second stack of LED 33. The second stack of LED 33 can be formed by semiconductor layers based on nitride gallium and may include a layer of GaInN well. The second substrate 31 is a substrate on which the gallium nitride-based semiconductor layer can be grown and can be the same as the third substrate 41. A proportion of GaInN composition can be determined so that the second LED stack 33 emit green light. The second transparent electrode p 35 is in ohmic contact with the p-type semiconductor layer of the second LED stack 33.
[0278] [0278] The third connection layer 157 is provided in the second color filter 47 and the second substrate 31 is arranged so that the second transparent electrode p 35 of the second substrate 31 is in contact with the third connection layer
[0279] [0279] Referring to FIG. 12C, the second substrate 31 is then separated from the second LED stack 23. The second substrate 31 can be separated from the second LED stack 33, using techniques such as laser lifting, chemical lifting or the like. As the second substrate 31 is separated, the second LED stack 33 is exposed. Then, the second transparent electrode n is formed on the exposed second LED stack 33. The second transparent electrode n 139 can be formed of a layer of metal or conductive oxide. According to an exemplary embodiment, the second transparent electrode No. 139 can be omitted.
[0280] [0280] Referring to FIG. 12D, the first stack of LED 23 is grown on the first substrate 21, the first transparent electrode p 125 is formed on the first stack of LED 23 and the first color filter 137 is formed on the first transparent electrode p 125.
[0281] [0281] The first substrate 21 can be, for example, a GaAs substrate. In addition, the first LED stack 23 consists of semiconductor layers based on AlGaInP and includes a n-type semiconductor layer, an active layer and a p-type semiconductor layer. The first transparent electrode p 125 is in ohmic contact with the p-type semiconductor layer of the first LED stack 23.
[0282] [0282] The first color filter 137 is substantially the same as that described with reference to FIG. 1 and, therefore, detailed descriptions will be omitted to avoid redundancy.
[0283] [0283] The second connection layer 155 is provided on the second transparent electrode n 139, and the first substrate 21 is arranged so that the first color filter 137 of the first substrate 21 is in contact with the second connection layer
[0284] [0284] Referring to FIG. 12E, after the first stack of LED 23 is connected to the second stack of LED 33, the first substrate 21 is removed from the first stack of LED 23 using a chemical etching technique. Thus, the first LED stack 23 is exposed.
[0285] [0285] Referring to FIG. 12F, the first reflective electrode No. 129 is formed on the first exposed LED stack 23. The first reflective electrode 129 includes a metal layer reflecting the light generated in the first LED stack 23. Then, the first connecting layer 153 is disposed on the first reflective electrode 129, and the supporting substrate 51 is attached thereto. Then, the third substrate 41 can be separated from the third LED stack 43, using techniques such as laser lifting, chemical lifting and the like. In this way, a stack of light-emitting diodes 101 for a display in which the n-type semiconductor layer of the third LED stack 43 is exposed as shown in FIG. 11 can be provided.
[0286] [0286] A display device can be formed by standardizing the stack of light-emitting diodes 101, including the first to the third LED batteries 23, 33 and 43 arranged on the supporting substrate 51 in pixel units and connecting the first to the third batteries LEDs 22, 33 and 43 by interconnection lines.
[0287] [0287] According to exemplary modalities, the plurality of pixels can be formed at a wafer level using the stack of light emitting diodes 100 or 101 for a display, which can impede the process of individual assembly of the light emitting diodes . In addition, since the first to third LED batteries 23, 33 and 43 have a vertically stacked structure, an area of the subpixel can be protected within a limited pixel area. In addition, as the light generated in the first battery of LED 23, the second battery of LED 33 and the third battery of LED 43 are transmitted through the second and third batteries of LED 33 and 43 and emitted to the outside, it is possible to reduce the loss of light.
[0288] [0288] FIG. 13 is a schematic plan view of a display device according to an exemplary embodiment, and FIG. 14 is a schematic cross-sectional view of a pixel of LED light for a display according to an exemplary embodiment.
[0289] [0289] Referring to FIG. 13, the display device 200 includes a support substrate 251 and a plurality of pixels 20 arranged on the support substrate 251. Each pixel 20 includes the first to the third subpixels R, G and B.
[0290] [0290] Referring to FIG. 14, the support substrate 251 supports the LED stacks 223, 233 and 243. The support substrate 251 may have a circuit on a surface or inside, but the inventive concepts are not limited to these. The support substrate 251 can include, for example, a glass substrate, a sapphire substrate, a Si substrate, or a Ge substrate.
[0291] [0291] The first subpixel R includes the first battery of LED 223, the second subpixel G includes the second battery of LED 233 and the third subpixel B includes the third battery of LED 243. The first subpixel R is configured to emit light in the first LED stack 223, the second subpixel G is configured to emit light in the second LED stack 233 and the third subpixel B is configured to emit light in the third LED stack 243. The first to the third LED batteries 223, 233 and 243 can be triggered independently of each other.
[0292] [0292] The first LED stack 223, the second LED stack 233 and the third LED stack 243 are stacked in the vertical direction and overlap. In particular, the second LED battery 233 is arranged in a partial region of the first LED battery
[0293] [0293] One portion of R light generated in the first LED battery 223 can be emitted in a region not covered with the second LED battery 233, another portion of R light can be emitted through the second LED battery 233 and the other portion can be emitted through each of the second 233 LED battery and the third 243 LED battery. A portion of the G light generated in the second 233 LED battery can be emitted in a region not covered with the third 243 LED battery and the another portion can be emitted through the third cell of LED 243. The light B generated in the third cell of LED 243 can be emitted through its upper surface.
[0294] [0294] In general, in the first 223 LED stack, a region covered with the second 233 LED stack may experience light loss, and therefore a higher intensity light per unit area can be emitted in a region not covered with the second LED stack
[0295] [0295] For example, when the first battery of LED 223 emits red light, the second battery of LED 233 emits green light and the third battery of LED 243 emits blue light, since the green light has a high visibility, it can be necessary to decrease the intensity of green light. As such, the area of the region of the second LED battery 233 that is not covered with the third LED battery 243 may be smaller than the area of the third LED battery 243. Furthermore, since the red light has low visibility, it can be necessary to increase the intensity of red light. As such, the area of the region of the first LED battery 223 that is not covered with the second LED battery 233 may be larger than the area of the third LED battery 243.
[0296] [0296] The first LED stack 223, the second LED stack 233 and the third LED stack 243 include a n-type semiconductor layer, a p-type semiconductor layer and an active layer interposed between them. The active layer can have a multi-quantum well structure. The first to the third LED batteries 223, 233 and 243 can include different active layers and therefore can emit light at different wavelengths. For example, the first 223 LED battery can be an inorganic light emitting diode that emits red light, the second 233 LED battery can be an inorganic light emitting diode that emits green light, and the third 243 LED battery can be an inorganic LED emitting blue light. To this end, the first LED stack 223 may include a GaInP based well layer, and the second LED stack 233 and the third LED stack 243 may include a GaInN based well layer.
[0297] [0297] FIG. 15 is a schematic circuit diagram of a display device according to an exemplary embodiment.
[0298] [0298] Referring to FIG. 15, a display device, according to an exemplary modality, can be implemented to be operated in a passive matrix manner. As described with reference to FIGS. 13 and 14, a pixel includes the first to the third subpixel R, G and B. The first LED stack 223 of the first subpixel R emits light at the first wavelength, the second LED stack 233 of the second subpixel G emits light with a second wavelength and the third LED stack 243 of the third subpixel B emits light with a third wavelength. The cathodes from the first to the third subpixel R, G and B can be connected to a common line, for example, a data line Vdata 225, and their anodes can be connected to different lines, for example, Vscan scan lines 271, 273 and
[0299] [0299] More particularly, the cathodes from the first to the third subpixel R, G and B of a first pixel are connected in common to the data line Vdata1, and their anodes are connected to the scan lines Vscan1-1, Vscan1-2 and Vscan1 -3. Thus, the subpixels R, G and B in the same pixel can be triggered individually.
[0300] [0300] In addition, each of the LED batteries 223, 233 and 243 can be activated in a pulse width modulation scheme or by changing the current intensity, thus adjusting the luminance of each subpixel. In addition, it is possible to adjust the luminance by adjusting an area from the first to the third LED batteries 223, 233 and 243 and an area from a region where the LED batteries 223, 233 and 243 do not overlap, as shown in FIG. 14.
[0301] [0301] FIG. 16 is a schematic plan view of a display device according to an exemplary embodiment. The display device 200A includes a plurality of pixels 20A aligned on a support substrate 251 according to a circuit diagram of FIG. 15. FIG. 17 is an enlarged plan view of a pixel region 20A of the display device of FIG. 16. FIGS. 18A to 18D are schematic cross-sectional views taken along lines A-A, B-B, C-C and D-D of FIG. 17, respectively.
[0302] [0302] Referring to FIGS. 16, 17, 18A, 18B, 18C and 18D, the display device 200A may include support substrate 251 and a plurality of pixels 20A arranged on support substrate 251. Each pixel 20A includes from the first to the third subpixels R, G and B. More particularly, pixel 20A includes the first LED battery 223, the second LED battery 233, the third LED battery 243, a reflective electrode 225, the first ohmic electrode 229, a second transparent electrode 236, a second electrode ohmic 237, a second current spreader layer 239, a third transparent electrode 246, a third ohmic spreader 247, a third current spreader layer 249, a first color filter 235, a second color filter 245, a first layer connection layer 253, a second connection layer 255, a third connection layer 257, an insulation layer 227, a lower insulation layer 261, an upper insulation layer 263, interconnect lines 271, 273 and 275 and connectors 271a , 273a, 275a, 277a and 277b.
[0303] [0303] Each subpixel R, G and B is connected to reflector electrodes 225 and interconnect lines 271, 273 and 275. As shown in Fig. 15, reflector electrode 225 can be used as the Vdata data line and the lines interconnect switches 271, 273 and 275 can be used as the Vscan scan line.
[0304] [0304] As shown in Fig. 16, pixels 20A can be arranged in a matrix form, the cathodes of the sub-pixels R, G and B of each pixel 20A are connected in common to the reflective electrode 225 and their anodes are connected to the lines of interconnection 271, 273 and 275, respectively, which are spaced from each other. Connectors 271a, 273a and 275a can connect interconnect lines 271, 273 and 275 with subpixels R, G and B, respectively.
[0305] [0305] The support substrate 251 supports the LED stacks 223, 233 and 243. The support substrate 251 may have a circuit on the surface or inside it, but the inventive concepts are not limited to these. The support substrate 251 can include, for example, a glass substrate, a sapphire substrate, a Si substrate, or a Ge substrate.
[0306] [0306] The first LED stack 223 includes a first semiconductor layer of conductivity type 223a and a second semiconductor layer of conductivity type 223b, the second LED stack 233 includes a first semiconductor layer of conductivity type 233a and a second layer conductivity type semiconductor 233b, and the third LED stack 243 includes a first conductivity type semiconductor layer 243a and a second conductivity type semiconductor layer 243b. In addition, although not shown, an active layer can be interposed between the first semiconductor layers of conductivity type 223a, 233a and 243a and the second semiconductor layers of conductivity type 223b, 233b and 243b, respectively.
[0307] [0307] According to an exemplary embodiment, the first semiconductor layers of conductivity type 223a, 233a and 243a are semiconductor layers of type n and the second semiconductor layers of conductivity type 223b, 233b and 243b are semiconductor layers of type p, respectively . A rough surface can be formed on at least one surface of the first semiconductor layers of conductivity type 223a, 233a and 243a by surface textures.
[0308] [0308] The first battery of LED 223 is disposed closer to the support substrate 251, the second battery of LED 233 is disposed in the first battery of LED 223 and the third battery of LED 243 is disposed in the second battery of LED 233. In addition In addition, the second 233 LED battery is arranged in a partial region of the first 223 LED battery, and therefore the first 223 LED battery partially overlaps the second 233 LED battery. In addition, the third 243 LED battery is arranged in a partial region of the second LED battery 233 and thus the second LED batteries 223 and 233 partially overlap the third LED battery 243. As such, at least a portion of the light generated in the first LED battery 223 can be emitted to the outside without going through the second and third LED batteries 233 and 243. In addition, at least a portion of the light generated in the second LED battery 233 can be emitted to the outside without going through the third LED battery 243.
[0309] [0309] The first LED battery 223, the second LED battery 233 and the third LED battery 243 can include substantially the same material as that of the LED batteries 223, 233 and 234 of FIG. 14 and, therefore, detailed descriptions will be omitted to avoid redundancy.
[0310] [0310] The reflective electrode 225 is in ohmic contact with a lower surface of the first LED stack 223, more particularly, the first semiconductor layer of conductivity type 223a. The reflective electrode 225 includes a reflective layer to reflect the light emitted from the first 223 LED cell. The reflective electrode 225 can substantially overlap the entire bottom surface of the first 223 LED cell. In addition, the reflective electrode 225 can be connected in common to the plurality of pixels 20a and used as the data line Vdata.
[0311] [0311] The reflective electrode 225 may be formed of a layer of material that forms an ohmic contact with the second semiconductor layer of conductivity type 223b of the first LED stack 223 and may also include a reflective layer that reflects the light generated in the first 223 LED battery, for example, red light.
[0312] [0312] The reflective electrode 225 may include an ohmic reflective layer and may be formed, for example, by an Au-Te alloy, an Au-Ge alloy or the like. These alloys have high reflectance to light in a red region and form an ohmic contact with the first semiconductor layer of conductivity type 223a.
[0313] [0313] The first ohmic electrode 229 is in ohmic contact with the second semiconductor layer of conductivity type 223b of the first subpixel R. The first ohmic electrode 229 can be formed by, for example, an Au-Zn alloy, an Au- Be, or similar. The first ohmic electrode 229 may include a pad region and an extension part. As shown in Fig. 18B, a connector 275a can be connected to the pad region of the first ohmic electrode 229. The first ohmic electrode 229 can be spaced from the second LED stack 233.
[0314] [0314] The second ohmic electrode 237 is in ohmic contact with the first semiconductor layer of conductivity type 233a of the second LED stack 233. The second ohmic electrode 237 can be disposed in the first semiconductor layer of conductivity type 233a. For example, the second semiconductor layer of conductivity type 233b and the active layer disposed in the first semiconductor layer of conductivity type 233a can be partially removed to expose the first semiconductor layer of conductivity type 233a and the second ohmic electrode 237 can be arranged in the first exposed semiconductor layer of conductivity type 233a.
[0315] [0315] As shown in Fig. 18C, connector 277b can electrically connect the second ohmic electrode 237 to the reflective electrode 225. The second ohmic electrode 237 can be spaced from the third LED stack 243.
[0316] [0316] The second transparent electrode 236 is in ohmic contact with the second semiconductor layer of conductivity type 233b on an upper surface of the second LED stack 233. The second transparent electrode 236 can cover substantially all regions of the second type semiconductor layer conductivity 233b. As such, the second transparent electrode 236 can wrap the third LED stack 243 in a flat view, while it is interposed between the second LED stack 233 and the third LED stack 243. The second transparent electrode 236 can be formed by a layer of transparent oxide or a layer of transparent metal.
[0317] [0317] The second transparent electrode 236, according to an exemplary embodiment, is disposed on the side of the upper surface of the second LED stack 233, which is relatively further away from the support substrate 251. In this way, the second transparent electrode 236 it can be formed in the second 233 LED stack after the growth of a substrate from the second 233 LED stack is removed. As such, the second transparent electrode 236 is prevented from being damaged during removal of the growth substrate.
[0318] [0318] The second current spreading layer 239 can be disposed on the second transparent electrode 236 and can be electrically connected to the second semiconductor layer of conductivity type 233b through the second transparent electrode
[0319] [0319] The second ohmic electrode 237 and the second current spreading layer 239 can be formed together with the same layer of material during the same process. Therefore, the second ohmic electrode 237 and the second current spreading layer 239 can have substantially the same layer structure.
[0320] [0320] The third ohmic electrode 247 is in ohmic contact with the first semiconductor layer of conductivity type 243a of the third LED stack 243. The third ohmic electrode 247 can be arranged in the first semiconductor layer of conductivity type 243a. For example, the second semiconductor layer of conductivity type 243b and the active layer disposed in the first semiconductor layer of conductivity type 243a can be partially removed to expose the first semiconductor layer of conductivity type 243a and the third ohmic electrode 247 can be arranged in the first semiconductor layer exposure of conductivity type 243a. As shown in Fig. 18D, connector 277a can electrically connect the third ohmic electrode 247 to reflective electrode 225.
[0321] [0321] The third transparent electrode 246 may be in ohmic contact with the second semiconductor layer of conductivity type 243b of the third LED stack 243. The third transparent electrode 246 can substantially cover all regions of the second semiconductor layer of conductivity type 243b . The third transparent electrode 246 can be formed by a layer of transparent oxide or a layer of transparent metal.
[0322] [0322] The third transparent electrode 246, according to an exemplary embodiment, is disposed on the side of the upper surface of the third LED stack 243, which is relatively further away from the support substrate 251. In this way, the third transparent electrode 246 can be formed in the third LED stack 243 after a growth substrate from the third LED stack 243 is removed. Therefore, the third transparent electrode 246 is prevented from being damaged during removal of the growth substrate.
[0323] [0323] The third current spreading layer 249 can be disposed on the third transparent electrode 246 and can be electrically connected to the second semiconductor layer of conductivity type 243b through the third transparent electrode 246. The third current spreading layer 246 can include a pad region and an extension part, and as shown in FIG. 18D, connector 271a can be connected to the pad region of the third current spread layer 249.
[0324] [0324] Each of the first ohmic electrode 229, the second current spreading layer 239 and the third current spreading layer 246 may include an extension portion to assist in the dispersion of current within each LED stack.
[0325] [0325] The third ohmic electrode 247 and the third current spreading layer 249 can be formed together with the same layer of material during the same process. Accordingly, the third ohmic electrode 247 and the third current spreading layer 249 may have substantially the same layer structure. In addition, the entire second ohmic electrode 237, the second current spreading layer 239, the third ohmic electrode 247 and the third current spreading layer 249 can be formed in the same process and have substantially the same layer structure.
[0326] [0326] The first color filter 235 can be disposed between the first battery of LED 223 and the second battery of LED 233. In addition, the second color filter 245 can be disposed between the second battery of LED 233 and the third battery LED light 243. The first color filter 235 transmits light generated in the first LED battery 223 and reflects the light generated in the second LED battery
[0327] [0327] According to some exemplary modalities, the first color filter 237 can reflect the light generated in the third LED stack 243.
[0328] [0328] Each of the first and second color filters 235 and 245 can be, for example, a low pass filter that passes through only a low frequency region, that is, a long wavelength region, a bandwidth that passes through only a predetermined wavelength range, or a band interrupt filter that blocks only the predetermined wavelength range. In particular, the first and second color filters 237 and 247 can be formed by alternately stacking the insulation layers with different refractive indices. For example, the first and second color filters 235 and 245 can be formed by alternately stacking TiO2 and SiO2. In particular, the first and second color filters 235 and 245 may include a distributed Bragg reflector (DBR). The 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 alternately stacking the insulation layers with different refractive indices.
[0329] [0329] The first link layer 253 couples the first LED stack 223 to the support substrate 251. The reflective electrode 225 can be in contact with the first link layer 253. The first link layer 253 can be transmissive or non-transmissive of light. The first bonding layer 253 can be formed by a layer of organic material or a layer of inorganic material. Examples of the organic layer can include SU8, poly (methylmethacrylate) (PMMA), polyimide, parylene, benzocyclobutene (BCB) or the like. Examples of the inorganic layer can include Al2O3, SiO2, SiNx or the like. The layer of organic material can be bonded at high vacuum and high pressure. The layers of inorganic material can be planarized across the surface by, for example, a mechanical chemical polishing process, so the surface energy can be controlled using plasma, or the like, and can be connected in high vacuum using the surface energy. In particular, by using a light-absorbing adhesive layer, such as black epoxy, as in the first bonding layer 253, a contrast ratio of the display device can be improved. The first bonding layer 253 can also be formed of spin-on-glass.
[0330] [0330] The second layer of connection 255 couples the first battery of LED 223 to the second pile of LED 233. The second layer of connection 255 can be arranged between the first pile of LED 223 and the first color filter 235. The second layer connector 255 may transmit light generated in the first LED stack 223 and may be formed from the transmissive light connector material described above with reference to the first connector layer 253.
[0331] [0331] The insulation layer 227 can be interposed between the second connection layer 255 and the first LED stack 223. The insulation layer 227 can be in contact with the second semiconductor layer of conductivity type 223b. The insulation layer 227 can be formed, for example, by SiO2, thus improving the bond strength of the second bond layer
[0332] [0332] The third layer of connection 257 couples the second battery of LED 233 and the third battery of LED 243. The third layer of connection 257 can be arranged between the second battery of LED 236 and the second color filter 245 to connect the second LED stack 236 and the second color filter 245. The third link layer 257 can transmit light generated in the first and second LED cells 223 and 233 and can be formed from the light transmitting link material described above with reference to the first connection layer 253.
[0333] [0333] The bottom insulation layer 261 can cover the first to third batteries of LEDs 223, 233 and 243. In particular, the bottom insulation layer 261 covers the reflective electrode 225 exposed around the first battery of LEDs 223. Meanwhile , the bottom insulation layer 261 may have openings to provide an electrical connection path.
[0334] [0334] The top insulation layer 263 covers the bottom insulation layer 261. The top insulation layer 263 can also have openings to provide an electrical connection path.
[0335] [0335] The lower insulation layer 261 and the upper insulation layer 263 are not particularly limited as long as they have insulating properties and can be formed, for example, by silicon oxide or silicon nitride.
[0336] [0336] As shown in Figs. 16 and 17, interconnect lines 271, 273 and 275 can be arranged to be orthogonal to the exposed reflector electrode 225 in plan view. The interconnect line 271 and the interconnect line 275 can be arranged in the upper insulating layer 263 and can be connected to the third current spreading layer 249 and the first ohmic electrode 229 through connectors 271a and 275a, respectively. To this end, the upper insulation layer 263 and the lower insulation layer 261 may have openings that expose the third ohmic electrode 247 and the first ohmic electrode 229.
[0337] [0337] The interconnect line 273 is arranged in the lower insulation layer 261 and is isolated from the reflective electrode 225. The interconnect line 273 can be arranged between the lower insulation layer 261 and the upper insulation layer 263 and can be connected to the second current spreading layer 239 through connector 273a. For this purpose, the lower insulation layer 261 has an opening exposing the second current spreading layer 239.
[0338] [0338] Connectors 277a and 277b are disposed between the lower insulation layer 261 and the upper insulation layer 263, respectively. As such, the third ohmic electrode 247 and the second ohmic electrode 237 are electrically connected to the reflective electrode 225. For this purpose, the lower insulation layer 261 may have openings that expose the third ohmic electrode 247 and the second ohmic electrode 237.
[0339] [0339] Interconnect line 271 and interconnect line 273 can be isolated from each other by the top insulating layer 263 and, thus, interconnect lines 271 and 273 can be arranged to overlap in the vertical direction.
[0340] [0340] The display device 200A of FIGS. 16 to 18 have a structure in which the electrodes of each pixel are connected to the data lines and the scan lines. In particular, the interconnect lines 271 and 275 of FIG. 16 are arranged in the upper insulation layer 263 and the interconnect line 273 is arranged between the lower insulation layer 261 and the upper insulation layer 263. However, the inventive concepts are not limited to these. For example, interconnect lines 271 and 275 can be formed in the bottom insulation layer 261 together with interconnect line 273 and can be covered with the top insulation layer 263, and connectors 271a and 275a can be formed in the insulation layer. superior insulation 263.
[0341] [0341] In the following, a method of manufacturing a 200A display device according to the exemplary embodiment described above will be described.
[0342] [0342] FIGS. 19A to 33 are schematic plan views and cross-sectional views illustrating a method of manufacturing a display device according to exemplary modalities. In FIGS. 19A to 33, several cross-sectional views are taken along line A-A of the corresponding plan view.
[0343] [0343] Referring to FIGS. 19A and 19B, the first LED stack 223 is grown on the first substrate 21. The first substrate 21 can be, for example, a GaAs substrate. The first LED stack 223 is formed with semiconductor layers based on AlGaInP and includes a first semiconductor layer of conductivity type 223a, an active layer and a second semiconductor layer of conductivity type 223b.
[0344] [0344] Insulation layer 227 can be formed in the first stack of LED 223. Insulation layer 227 can be standardized to have openings that expose the second semiconductor layer of conductivity type 223b. The insulation layer 227 can be formed by a layer of hydrophilic material, for example, SiO2. According to an exemplary embodiment, the insulation layer 227 can be omitted.
[0345] [0345] The first ohmic electrode 229 can be formed at the opening of the insulation layer 227. The first ohmic electrode 229 can be formed, for example, by an Au-Zn alloy, an Au-Be alloy or the like. The first ohmic electrode 229 can be formed to have a pad region and an extension part. The first ohmic electrode 229 can be formed by an elevation technique and be formed in each pixel region. The first ohmic electrode 229 can be arranged on one side of a pixel region, as shown in FIG. 19A.
[0346] [0346] Next, with reference to FIG. 20A, a preliminary substrate 321a can be attached to the first LED stack 223 through the link layer 323a. The preliminary substrate 321a is not particularly limited and can be any substrate capable of supporting the first LED stack 223. Meanwhile, the first substrate 221 is removed from the first LED stack 223 using an etching technique to expose the first semiconductor layer. conductivity type 223a of the first LED stack 223. The exposed surface of the first conductivity type 223a semiconductor layer can be roughened by surface texturing.
[0347] [0347] The reflector electrode 225 is formed on the first exposed LED 223 battery. The reflective electrode 225 can be formed, for example, by an Au-Te alloy, an Au-Ge alloy or the like. The reflective electrode 225 can be formed using a lifting technique and can be standardized to have a specific shape. For example, the reflective electrode 225 can be standardized to have a shape that longitudinally connects a plurality of pixels. However, the inventive concepts are not limited to these, and the reflective electrode 225 can be formed substantially over the entire surface of the first LED stack 223 without standardizing and then standardizing in later stages. The reflective electrode 225 may be in ohmic contact with the first conductivity type semiconductor layer 223a of the first LED stack 223, which may be the n type semiconductor layer.
[0348] [0348] Referring to FIG. 20B, the support substrate 251 is connected to the first LED stack 223 through the first connection layer 253. The reflective electrode 225 in the first LED stack 223 can be arranged to face the support substrate 251 to be connected to the support substrate 251. Thus, the first bonding layer 253 can be in contact with the reflective electrode 225 and the first semiconductor layer of conductivity type 223a.
[0349] [0349] After bonding substrate 251, preliminary substrate 321a and bonding layer 323a can be removed. Thus, the insulation layer 227 and the first ohmic electrode 229 can be exposed.
[0350] [0350] Referring to FIG. 21A, the second LED stack 233 is grown on the second substrate 31. The second LED stack 233 can be formed by semiconductor layers of gallium nitride and can include a first conductivity semiconductor layer 233a, a GaInN well layer and a second semiconductor layer of conductivity type 233b. The second substrate 31 is a substrate on which the gallium nitride-based semiconductor layer can be grown and may be different from the first substrate 21. A proportion of GaInN composition can be determined so that the second LED stack 233 emits light green.
[0351] [0351] Referring to FIG. 21B, a preliminary substrate 321b is attached to the second LED stack 233 through the link layer 323b. The preliminary substrate 321b is not particularly limited and can be any substrate capable of supporting the second LED stack 233.
[0352] [0352] Referring to FIG. 21C, the second substrate 231 is then removed. The second substrate 31 can be separated from the second LED stack 233 using techniques, such as laser lifting, chemical lifting or the like, to expose the first conductivity type semiconductor layer 233a from the second LED stack 233. The exposed surface of the first layer conductivity type 233a semiconductor can be roughened by surface texturing.
[0353] [0353] The first color filter 235 can be formed in the first semiconductor layer of exposed conductivity type 233a. The first color filter 235 may be in contact with the first semiconductor layer of conductivity type 233a. The material of the first color filter 235 is substantially the same as that of FIG. 18A, detailed descriptions of it will be omitted to avoid redundancy.
[0354] [0354] Referring to FIG. 22A, the third LED stack 243 is grown on the third substrate 41. The third LED stack 243 can be formed of semiconductor layers based on gallium nitride and can include a first semiconductor layer of conductivity type 243a, a GaInN well layer and a second semiconductor layer of conductivity type 243b. The third substrate 41 is a substrate on which the gallium nitride-based semiconductor layer can be grown and may be different from the first substrate 21. A proportion of GaInN composition can be determined so that the third LED stack 243 emits light blue.
[0355] [0355] Referring to FIG. 22B, a preliminary substrate 321c is attached to the third LED stack 243 through the link layer 323c. The preliminary substrate 321c is not particularly limited and can be any substrate capable of supporting the third LED stack 243.
[0356] [0356] Referring to FIG. 22C, the third substrate 41 is then removed. The third substrate 41 can be separated from the third LED stack 243 using techniques such as laser lifting, chemical lifting or the like, to expose the first semiconductor layer of conductivity type 243a from the third LED stack 243. The exposed surface of the first semiconductor layer conductivity type 243a can be rough by surface texturing.
[0357] [0357] The second color filter 245 can be formed on the first semiconductor layer of exposed conductivity type 243a. The second color filter 245 may be in contact with the first semiconductor layer of conductivity type 243a. The material of the second color filter 245 is substantially the same as that of FIG. 18A and, therefore, detailed descriptions of it will be omitted to avoid redundancy.
[0358] [0358] Meanwhile, since the first 223 LED battery, the second 233 LED battery and the third 243 LED battery grow on different substrates, the order of formation of the LED batteries is not particularly limited.
[0359] [0359] Referring to FIGS. 23A and 23B, first, the second LED stack 233 of FIG. 21C is connected to the exposed insulation layer 227 and the first ohmic electrode 229 of FIG. 20B through the second connection layer 255.
[0360] [0360] The first color filter 235 can be arranged to face the support substrate 251 and connected to the insulation layer 227 through the second connection layer 255. The second connection layer 255 can be formed of light transmitting material
[0361] [0361] Subsequently, the preliminary substrate 321b and the connecting layer 323b are removed to expose the second semiconductor layer of conductivity type 233b and the second transparent electrode 236 is formed in the second semiconductor layer of conductivity type 233b exposed. The second transparent electrode 236 is in ohmic contact with the second semiconductor layer of conductivity type 233b. The second transparent electrode 236 can cover substantially all regions of the second semiconductor layer of conductivity type 233b.
[0362] [0362] Since the second transparent electrode 236 is formed after the second substrate 31 is removed from the second LED stack 233, the second transparent electrode 236 can be prevented from being damaged during a process of removing the second substrate 231.
[0363] [0363] Referring to FIGS. 24A and 24B, the third LED battery
[0364] [0364] The second color filter 245 can be arranged to face the second battery of LED 233 and connected to the second transparent electrode 236 through the third connection layer 257. The third connection layer 257 can be formed by light transmitting material
[0365] [0365] Subsequently, the preliminary substrate 321c and the connecting layer 323c are removed to expose the second semiconductor layer of conductivity type 243b, and the third transparent electrode 246 is formed in the second semiconductor layer of conductivity type 243b exposed. The third transparent electrode 246 is in ohmic contact with the second semiconductor layer of conductivity type 243b. The third transparent electrode 246 can cover substantially all regions of the second semiconductor layer of conductivity type 243b.
[0366] [0366] Referring to FIGS. 25A and 25B, the third transparent electrode 246, the second semiconductor layer of conductivity type 243b and the active layer are modeled to expose the first semiconductor layer of conductivity type 243a in each pixel region. The third transparent electrode 246 may remain as long as it is defined within a third subpixel region and may include a recessed portion, as shown in FIG. 25A.
[0367] [0367] Then, the third ohmic electrode 247 and the third current spreading layer 249 are formed on the third transparent electrode 246 and the first semiconductor layer of conductivity type 243a, respectively. The third ohmic electrode 247 can be formed in the recessed part. The third ohmic electrode 247 and the third current scattering layer 249 can be formed with the same layer of material during the same process, and therefore the third ohmic electrode 247 and the third current scattering layer 249 can have substantially the same structure. However, the inventive concepts are not limited to these, and the third ohmic electrode 247 and the third current spreading layer 249 can be formed in separate processes. For example, the third current spreading layer 249 can be formed before the third transparent electrode 246 is standardized and the third ohmic electrode 247 can be formed after the first conductivity type semiconductor layer 243a is exposed, or vice versa. In addition, the third ohmic electrode 247 and the third current spreading layer 249 can be formed together with the second current spreading layer 239 to be described below.
[0368] [0368] Referring to FIGS. 26A and 26B, the second transparent electrode 236 is exposed by sequentially standardizing the first conductivity type semiconductor layer 243a, the second color filter 245 and the third link layer 257. In this way, the third region of subpixel B is defined and the second transparent electrode 236 is exposed around the third region of subpixel B.
[0369] [0369] Referring to FIGS. 27A and 27B, the second transparent electrode 236, the second semiconductor layer of conductivity type 233b and the active layer are standardized to expose the first semiconductor layer of conductivity type 233a. The second transparent electrode 236 may remain as long as it is defined within a second subpixel region and may include a recessed portion, as shown in FIG. 27A.
[0370] [0370] Then, the second ohmic electrode 237 and the second current spreading layer 239 are formed on the second transparent electrode 236 and the first semiconductor layer 233a of the conductivity type, respectively. The second ohmic electrode 237 can be formed in the recessed part. The second ohmic electrode 237 and the second current spreading layer 239 can be formed with the same layer of material during the same process, and thus the second ohmic electrode 237 and the second current spreading layer 239 can have substantially the same structure.
[0371] [0371] In addition, the third ohmic electrode 247 and the third current spreading layer 249 can also be formed together with the second ohmic electrode 237 and the second current spreading layer 239 with the same layer of material during the same process.
[0372] [0372] However, the inventive concepts are not limited to these, and the second ohmic electrode 237 and the second current spreading layer 239 can be formed in separate processes. For example, the second current spreading layer 239 can be formed first before the second transparent electrode 236 is standardized and the second ohmic electrode 237 can be formed after exposure of the first conductivity type semiconductor layer 233a or vice versa.
[0373] [0373] Referring to FIGS. 28A and 28B, the second transparent electrode 23b is exposed by sequentially patterning the first conductivity type semiconductor layer 233a, the first color filter 235, the second bonding layer 255 and the insulating layer 227. Thus, the second subpixel B is defined and the second semiconductor layer of conductivity type 223b is exposed around the second subpixel region G. In addition, the first ohmic electrode 229 is exposed on the outside of the second LED stack 233 and the second battery of LED 233 partially overlaps the third LED 243 battery. In particular, the third LED 243 battery is arranged to be defined within a region of the second 233 LED battery.
[0374] [0374] Referring to FIGS. 29A and 29B, the first 223 LED battery is standardized to remove the first 223 LED battery in a different portion of the first R subpixel region. Meanwhile, the first ohmic electrode 229 can remain in the first subpixel region R. The first LED stack 223 partially overlaps the second LED stack 233 and the third LED stack 243. In particular, the second LED stack 233 and the third LED stack 243 are arranged to be defined within a region of the first battery stack. LED 223.
[0375] [0375] Meanwhile, by standardizing the first LED stack 223, the reflective electrode 225 can be exposed and the surface of the first connection layer 253 can also be partially exposed. According to another exemplary embodiment, an insulating layer can be arranged on the first bonding layer 253 and therefore the insulating layer can be exposed instead of the first bonding layer 253.
[0376] [0376] According to an exemplary embodiment, each of the first ohmic electrode 229, the second current spreading layer 239 and the third current spreading layer 249 may include a pad region and an extension part, and the the extension part can extend along a length direction of the exposed reflector electrode 225. However, the inventive concepts are not limited to these.
[0377] [0377] Referring to FIGS. 30A and 30B, the bottom insulation layer 261 is then formed to cover the first to third LED batteries 223, 233 and 243, and the reflective electrode 225 and the first connection layer 253. The second transparent electrode 236 and the third electrode transparent 246 are also covered by the bottom insulation layer 261. The bottom insulation layer 261 can be patterned to form openings that expose the first ohmic electrode 229, the second ohmic electrode 237, the second current spread layer 239, the third electrode ohmic 247, the third current spreading layer 249 and the reflective electrode 225.
[0378] [0378] Referring to FIG. 31, interconnect line 273 and connectors 273a, 277a and 277b are formed in the bottom insulation layer 261. Connector 273a connects the second current spread layer 239 to interconnect line 273, connector 277a connects the third ohmic electrode 247 to the reflective electrode 225 and connector 277b connects the second ohmic electrode 237 to the reflective electrode 225. A schematic cross-sectional view taken along line AA of FIG. 31 is the same as in FIG. 30B.
[0379] [0379] Referring to FIGS. 32A and 32B, the top insulating layer 263 is then formed to cover the interconnect line 273 and the connectors 273a, 277a and 277b. The upper insulation layer 263 can be patterned to expose the pad regions of the first ohmic electrode 229 and the third current spreading layer 249.
[0380] [0380] Referring to FIG. 33, interconnect lines 271 and 275 and connectors 271a and 275a are then formed in the upper insulating layer 263. Connector 271a connects interconnect line 271 to the third current spread layer
[0381] [0381] As such, the display device 200A described with reference to FIGS. 16 and 17 is manufactured.
[0382] [0382] FIG. 34 is a schematic cross-sectional view illustrating a display device according to another exemplary embodiment.
[0383] [0383] Referring to FIG. 34, the display device according to an example is substantially similar to the display device of FIGS. 16 and 17, except that the transparent electrode 226 is disposed on the top surface of the first LED stack 223 and the first current spreading layer 229 is disposed on the transparent electrode 226. In particular, the transparent electrode 226 is disposed on the first semiconductor layer conductivity type 223a to be in ohmic contact with the first conductivity type 223a semiconductor layer. The transparent electrode 226 can substantially cover the entire upper surface of the first LED battery 223 and therefore can be interposed between the first LED battery 223 and the second LED battery 233, as well as the outside of the second LED battery 233 .
[0384] [0384] The transparent electrode 226 can be formed to cover most of the region of the second semiconductor layer of conductivity type 223b before forming the insulation layer 227 described with reference to FIG. 19A. In addition, the insulation layer 227 can be omitted. Meanwhile, the first current spreading layer 229 can be formed directly on the transparent electrode 226. Alternatively, the first current spreading layer 229 can be formed after the first conductivity type semiconductor layer
[0385] [0385] In this way, since the first current spreading layer 229 may not need to be in ohmic contact with the first semiconductor layer of conductivity type 223a, forming the transparent electrode 226, the first current spreading layer 229 it can be formed with the second current spreading layer 239 or the third current spreading layer 249 with the same layer of material. Thus, the first current spreading layer 229 can also be formed together with the same material layer during the same process by forming the second ohmic electrode 237, the second current spreading layer 239, the third ohmic electrode 247 and the third current spread layer 249.
[0386] [0386] Meanwhile, the display device of FIG. 34 is described as including pixels triggered in a passive matrix trigger manner, however, the inventive concepts are not limited to these, and pixels can be triggered in the active matrix trigger manner.
[0387] [0387] FIG. 35 is a schematic circuit diagram of a display device in accordance with yet another exemplary embodiment. Here, the circuit diagram of the display device is conducted in the active matrix manner.
[0388] [0388] Referring to FIG. 35, a drive circuit according to an exemplary embodiment includes two or more transistors Tr1 and Tr2 and a capacitor. When power is connected to the selection lines Vrow1 to Vrow3, and a data voltage is applied to the data lines Vdata1 to Vdata3, a voltage is applied to the corresponding LED. In addition, the charges are charged to the corresponding capacitor according to the values of Vdata1 and Vdata3. The transistor Tr2 can maintain an activation state by the charged voltage of the capacitor and thus, even when the power supply is cut off in the selection line Vrow1, the voltage of the capacitor can be maintained and the voltage can be applied to the light emitting diodes LED1 to LED3. In addition, the currents that flow through LED1 to LED3 can be changed according to the values from Vdata1 to Vdata3. As the current can always be supplied by Vdd, the light can be emitted continuously.
[0389] [0389] Transistors Tr1 and Tr2 and capacitor can be formed on a support substrate 251. The support substrate 251 can also have contact pads on its surface to connect the transistors to the capacitors. In addition, the selection line and the data line can be provided on the support substrate 251 and, therefore, the interconnect lines 271, 273 and 275 described above can be omitted.
[0390] [0390] The light emitting diodes LED1 to LED3 can correspond to the first to third batteries of LEDs 223, 233 and 243, respectively, in one pixel. The anodes from the first to the third LED cells 223, 233 and 243 are connected to transistor Tr2 and their cathodes are grounded. The first ohmic electrode 229, the second current spreading layer 239 and the third current spreading layer 249 can be connected to the connection pads on the supporting substrate 251, respectively, through the connectors to be connected to transistor Tr2 and the electrode reflector 225 can be connected to the support substrate connection pad 251 and grounded.
[0391] [0391] The first to the third LED batteries 223, 233 and 243 can be connected in common to the reflective electrode 225 and grounded. In addition, the reflective electrode 225 can be arranged continuously on two or more pixels, or on all pixels. Thus, the reflector electrode 225 can be connected in common to all LED batteries in the display device. In this way, noise from an active matrix drive circuit can be eliminated by placing the reflective electrode 225 between the pixels and the substrate 251.
[0392] [0392] Although FIG. 35 illustrate a circuit diagram for an active matrix according to an exemplary modality, but the inventive concepts are not limited to these, and other circuits can be used.
[0393] [0393] According to exemplary modalities, a plurality of pixels can be formed at a wafer level using a wafer connection and, thus, a display device can be formed without mounting the light emitting diodes individually.
[0394] [0394] FIG. 36 is a schematic cross-sectional view of a stack of LEDs for a display in accordance with an exemplary embodiment.
[0395] [0395] Referring to FIG. 36, the light emitting diode stack 1000 includes a support substrate 1510, a first stack of LED 1230, a second stack of LED 1330, a third stack of LED 1430, a reflective electrode 1250, an ohmic electrode 1290, a second transparent electrode 1350, a third transparent electrode p 1450, an insulating layer 1270, a first color filter 1370, a second color filter 1470, a first connection layer 1530, a second connection layer 1550 and a third connection layer 1570. In addition, the first stack of
[0396] [0396] The support substrate 1510 supports the semiconductor cells 1230, 1330 and 1430. The support substrate 1510 may include a circuit on a surface of the same or in it, but the inventive concepts are not limited to it. The support substrate 1510 can include, for example, a Si substrate or a Ge substrate.
[0397] [0397] Each of the first 1230 LED stack, the second 1330 LED stack and the 1430 LED stack includes a n-type semiconductor layer, a p-type semiconductor layer and an active layer interposed between them. The active layer can have a multi-quantum well structure.
[0398] [0398] For example, the first 1230 LED battery can be an inorganic light emitting diode configured to emit red light, the second 1330 LED battery can be an inorganic light emitting diode configured to emit green light and the third battery of LED 1430 can be an inorganic light emitting diode configured to emit blue light. The first 1230 LED stack can include a GaInP based well layer, and each of the second 1330 LED stack and the third 1430 LED stack can include a GaInN based well layer. However, the inventive concepts are limited to these, and when the stack of light-emitting diodes 1000 includes micro LEDs, the first 1230 LED stack can emit any one of red, green and blue light, and the second and third batteries of LEDs 1330 and 1430 can emit a light different from the red, green and blue lights without adversely affecting the operation or requiring color filters due to their small form factor.
[0399] [0399] In addition, both surfaces of each of the first to third LED batteries 1230, 1330, 1430 are a n-type semiconductor layer and a p-type semiconductor layer, respectively. In the exemplary embodiment illustrated, each of the first to third LED batteries 1230, 1330 and 1430 has an upper surface of type n and a lower surface of type p. Since the third battery of LED 1430 has an upper surface of type n, a rough surface can be formed on the upper surface of the third battery of LED 1430 through chemical engraving. However, the inventive concepts are not limited to them, and the types of semiconductors on the top and bottom surfaces of each of the LED cells can be arranged alternatively.
[0400] [0400] The first 1230 LED stack is arranged near the support substrate 1510, the second 1330 LED stack is placed on the first 1230 LED stack and the third 1430 LED stack is placed on the second 1330 LED stack. Once Since the first 1230 LED battery emits light with a longer wavelength than the second and third 1330 and 1430 LED batteries, the light generated from the first 1230 LED battery can be emitted externally through the second and third LED batteries. LEDs 1330 and 1430. In addition, since the second battery of 1330 LED emits light with a wavelength greater than the third battery of LED 1430, the light generated from the second battery of LED 1330 can be emitted out through of the third 1430 LED stack.
[0401] [0401] The reflective electrode 1250 forms ohmic contact with the p-type semiconductor layer of the first 1230 LED cell and reflects the light generated from the first 1230 LED cell. For example, the reflective electrode 1250 may include a contact layer ohmic 1250a and a reflective layer 1250b.
[0402] [0402] The ohmic contact layer 1250a partially contacts the p-type semiconductor layer of the first 1230 LED stack. To prevent light absorption by the ohmic contact layer 1250a, a region where the ohmic contact layer 1250a comes into contact Contact with the p-type semiconductor layer may not exceed 50% of the total area of the p-type semiconductor layer. The reflective layer 1250b covers the ohmic contact layer 1250a and the insulating layer 1270. As shown in Fig. 36, the reflective layer 1250b can cover substantially the entire ohmic contact layer 1250a, without being limited thereto. Alternatively, the reflective layer 1250b can cover a portion of the ohmic contact layer 1250a.
[0403] [0403] Since the reflective layer 1250b covers the insulating layer 1270, an omnidirectional reflector can be formed by the stacked structure of the first 1230 LED stack with a relatively high refractive index, and the insulating layer 1270 and the reflecting layer 1250b with a relatively low refractive index. The reflective layer 1250b can cover 50% or more of the area of the first 1230 LED battery, or most of the first 1230 LED battery, thus improving luminous efficiency.
[0404] [0404] The ohmic contact layer 1250a and the reflective layer 1250b can be metal layers, which can include Au. The reflective layer 1250b can be formed of a metal with a relatively high reflectance in relation to the light generated from the first stack of LED 1230, for example, red light. On the other hand, the reflective layer 1250b can be formed by a metal with relatively low reflectance in relation to the light generated from the second battery of LED 1330 and the third battery of LED 1430, for example, green light or blue light, to reduce light interference having been generated from the second and third LED batteries 1330 and 1430 and traveling towards the support substrate 1510.
[0405] [0405] The insulation layer 1270 is interposed between the supporting substrate 1510 and the first 1230 LED stack and has openings that expose the first 1230 LED stack. The ohmic contact layer 1250a is connected to the first 1230 LED stack in the openings of the insulation layer 1270.
[0406] [0406] The ohmic electrode 1290 is disposed on the top surface of the first 1230 LED battery. In order to reduce the ohmic contact resistance of the ohmic electrode 1290, the ohmic contact portion 1230a may protrude from the upper surface of the first 1230 LED battery. The ohmic electrode 1290 can be arranged in the ohmic contact portion 1230a.
[0407] [0407] The second transparent p 1350 electrode forms ohmic contact with the p type semiconductor layer of the second 1330 LED stack. The second transparent p 1350 electrode can include a metal layer or a conductive oxide layer that is transparent to red light. and green light.
[0408] [0408] The third transparent electrode p 1450 forms ohmic contact with the semiconductor type p of the third cell of LED 1430. The third transparent electrode p 1450 can include a metal layer or a layer of conductive oxide that is transparent to red light , green light and blue light.
[0409] [0409] The reflective electrode 1250, the second transparent electrode p 1350 and the third transparent electrode p 1450 can assist in the propagation of current through the ohmic contact with the p-type semiconductor layer of the corresponding LED stack.
[0410] [0410] The first 1370 color filter can be interposed between the first 1230 LED battery and the second 1330 LED battery. The second 1470 color filter can be interposed between the second 1330 LED battery and the third 1430 LED battery. The first 1370 color filter transmits light generated from the first 1230 LED battery while reflecting the light generated from the second 1330 LED battery. The second 1470 color filter transmits light generated from the first and second LED batteries. 1230 and 1330, while reflecting the light generated from the third battery of LED 1430. As such, the light generated from the first battery of LED 1230 can be emitted out through the second battery of LED 1330 and the third battery of LED 1430, and the light generated from the second 1330 LED battery can be emitted out through the third 1430 LED battery. In addition, the light generated from the second 1330 LED battery can be prevented from entering the first 1330 LED battery. LED 1230 and the light generated from the third battery of LED 1430 can be prevented from entering the second battery of LED 1330, thus preventing the loss of light.
[0411] [0411] In some exemplary embodiments, the first 1370 color filter can reflect the light generated from the third LED stack 1430.
[0412] [0412] The first and second color filters 1370 and 1470 can be, for example, a low pass filter that transmits light in a low frequency band, that is, in a long wavelength band, a bandpass filter which transmits light in a predetermined wavelength range, or a band interrupt filter that prevents light in a predetermined wavelength range from passing through it. In particular, each of the first and second color filters 1370 and 1470 may include a distributed Bragg reflector (DBR). The distributed Bragg reflector can be formed by alternately stacking layers of insulation with different refractive indices one above the other, for example, TiO2 and SiO2. In addition, the interruption range 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.
[0413] [0413] The first link layer 1530 couples the first stack of LED 1230 to the support substrate 1510. As shown in Fig. 36, the reflective electrode 1250 can join with the first link layer 1530. The first link layer 1530 it can be a transmissive layer or opaque to light.
[0414] [0414] The second connection layer 1550 couples the second battery of LED 1330 to the first battery of LED 1230. As shown in Fig. 36, the second connection layer 1550 can join the first battery of LED 1230 and the first color filter 1370. The ohmic electrode 1290 can be covered by the second connection layer 1550. The second connection layer 1550 transmits light generated from the first 1230 LED stack. The second connection layer 1550 can be formed, for example, by spin- light transmissive on-glass.
[0415] [0415] The third layer of link 1570 couples the third stack of LED 1430 to the second stack of LED 1330. As shown in Fig. 36, the third layer of link 1570 can join the second stack of LED 1330 and the second filter of color 1470. However, the inventive concepts are not limited to these. For example, a transparent conductive layer can be arranged on the second stack of LED 1330. The third layer of link 1570 transmits light generated from the first stack of LED 1230 and the second stack of LED 1330. The third layer of link 1570 can be formed, for example, by light transmissive spin-on-glass.
[0416] [0416] FIGS. 37A, 37B, 37C, 37D and 37E are schematic cross-sectional views that illustrate a method of manufacturing a stack of light-emitting diodes for a display according to an exemplary embodiment.
[0417] [0417] Referring to FIG. 37A, a first 1230 LED stack is grown on a first substrate 1210. The first substrate 1210 can be, for example, a GaAs substrate. The first 1230 LED stack can be formed by semiconductor layers based on AlGaInP and includes a n-type semiconductor layer, an active layer and a p-type semiconductor layer.
[0418] [0418] An insulating layer 1270 is formed on the first stack of LED 1230 and is standardized to form openings. For example, a SiO2 layer is formed on the first 1230 LED stack and a photoresistor is deposited on the SiO2 layer, followed by photolithography and development to form a photoresistor pattern. Then, the SiO2 layer is standardized using the photoresistor pattern used as an attack mask, thus forming the 1270 insulation layer.
[0419] [0419] Then, an ohmic contact layer 1250a is formed in the openings of the insulation layer 1270. The ohmic contact layer 1250a can be formed by a lifting process or the like. After the formation of the ohmic contact layer 1250a, a reflective layer 1250b is formed to cover the ohmic contact layer 1250a and the insulating layer 1270. The reflective layer 1250b can be formed by a lifting process or the like. The reflective layer 1250b can cover a portion of the ohmic contact layer 1250a or all of it, as shown in FIG. 37A. The ohmic contact layer 1250a and the reflective layer 1250b form a reflective electrode 1250.
[0420] [0420] The reflective electrode 1250 forms ohmic contact with the p-type semiconductor layer of the first 1230 LED stack and will therefore be referred to hereinafter as a first reflective electrode p 1250.
[0421] [0421] Referring to FIG. 37B, a second stack of LED 1330 is grown on a second substrate 1310 and a second transparent electrode p 1350 and a first color filter 1370 are formed on the second stack of LED 1330. The second stack of LED 1330 can be formed by layers of semiconductors based on GaN and include a GaInN well layer. The second substrate 1310 is a substrate on which the GaN-based semiconductor layers can be grown on it and is different from the first substrate 1210. The composition ratio of GaInN to the second 1330 LED stack can be determined so that the second 1330 LED battery emit green light. The second transparent p1350 electrode forms ohmic contact with the p-type semiconductor layer of the second 1330 LED battery.
[0422] [0422] Referring to FIG. 37C, a third stack of LED 1430 is grown on a third substrate 1410, and a third transparent electrode p 1450 and a second color filter 1470 are formed on the third stack of LED 1430. The third stack of LED 1430 can be formed by layers of GaN-based semiconductors and include a GaInN well layer. The third substrate 1410 is a substrate on which the GaN-based semiconductor layers can be grown on it and is different from the first substrate 1210. The ratio of GaInN composition to the third LED stack 1430 can be determined so that the third stack LED light emits blue light. The third transparent p 1450 electrode forms ohmic contact with the p-type semiconductor layer of the third 1430 LED battery.
[0423] [0423] The first color filter 1370 and the second color filter 1470 are substantially the same as those described with reference to FIG. 36 and, therefore, repeated descriptions will be omitted to avoid redundancy.
[0424] [0424] As such, the first 1230 LED stack, the second 1330 LED stack and the 1430 LED stack can be grown on different substrates, and the formation sequence is not limited to a specific sequence.
[0425] [0425] Referring to FIG. 37D, the first 1230 LED stack is coupled to the support substrate 1510 through a first bonding layer 1530. The first bonding layer 1530 can be formed previously on the supporting substrate 1510, and the reflective electrode 1250 can be attached to the first bonding layer 1530 for facing support substrate 1510. The first substrate 1210 is removed from the first stack of LED 1230 by chemical etching or the like. Therefore, the upper surface of the n-type semiconductor layer of the first 1230 LED stack is exposed.
[0426] [0426] Then, a 1290 ohmic electrode is formed in the exposed region of the first 1230 LED stack. In order to reduce the ohmic contact resistance of the 1290 ohmic electrode, the 1290 ohmic electrode can be heat treated. The ohmic electrode 1290 can be formed in each pixel region, in order to correspond to the pixel regions.
[0427] [0427] Referring to FIG. 37E, the second battery of LED 1330 is coupled to the first battery of LED 1230, on which the ohmic electrode 1290 is formed, through a second connection layer 1550. The first color filter 1370 is connected to the second connection layer 1550 for face the first stack of LED 1230. The second layer of connection 1550 can be formed previously on the first stack of LED 1230, so that the first color filter 1370 can be turned over and connected to the second layer of connection 1550. The second substrate 31 can be separated from the second 1330 LED battery by a laser lifting or chemical lifting process.
[0428] [0428] Then, with reference to FIG. 36 and FIG. 37C, the third battery of LED 1430 is coupled to the second battery of LED 1330 through a third layer of connection 1570. The second color filter 1470 is connected to the third layer of connection 1570 to face the second battery of LED 1330. The third connection layer 1570 can be pre-arranged on the second stack of LED 1330, so that the second color filter 1470 can be turned over and connected to the third link layer 1570. The third substrate 1410 can be separated from the third stack of LED 1430 by a laser lifting or chemical lifting process. As such, a stack of light-emitting diodes for a display can be formed as shown in FIG. 36, which has the n-type semiconductor layer of the third LED stack 1430 exposed to the outside.
[0429] [0429] A display device, according to an exemplary mode, can be provided by standardizing the stack of the first to the third LED batteries 1230, 1330 and 1430 on the supporting substrate 1510 in pixel units, followed by the connection of the first to the third LED batteries to each other through interconnections. In the following, a display device according to exemplary modalities will be described.
[0430] [0430] FIG. 38 is a schematic circuit diagram of a display device according to an exemplary embodiment, and FIG. 39 is a schematic plan view of a display device according to an exemplary embodiment.
[0431] [0431] Referring to FIG. 38 and FIG. 39, a display device, according to an exemplary embodiment, can be operated in a passive matrix manner.
[0432] [0432] For example, since the stack of light emitting diodes for a display of FIG. 36 includes the first to third batteries of LED 1230, 1330 and 1430 stacked in the vertical direction, a pixel can include three light-emitting diodes R, G and B. A first light-emitting diode R can correspond to the first battery of LED 1230, a second light-emitting diode G can correspond to the second battery of LED 1330 and a third light-emitting diode B can correspond to the third battery of LED 1430.
[0433] [0433] In FIGS. 38 and 39, a pixel includes the first to the third light emitting diodes R, G and B, each of which corresponds to a sub-pixel. The anodes of the first to the third light-emitting diodes R, G and B are connected to a common line, for example, a data line and their cathodes are connected to different lines, for example, scanning lines. More particularly, in a first pixel, the anodes from the first to the third light-emitting diodes R, G and B are commonly connected to a data line Vdata1 and their cathodes are connected to the scan lines Vscan1-1, Vscan1-2 and Vscan1 -3, respectively. As such, the light emitting diodes R, G and B at each pixel can be activated independently.
[0434] [0434] In addition, each of the light emitting diodes R, G and B can be activated by modulating the pulse width or changing the magnitude of the electric current, thus controlling the brightness of each subpixel.
[0435] [0435] Referring to FIG. 39, a plurality of pixels are formed by standardizing the stack of light emitting diodes 1000 of FIG. 36, and each of the pixels is connected to reflective electrodes 1250 and interconnect lines 1710, 1730 and 1750. As shown in Fig. 38, reflective electrode 1250 can be used as the Vdata data line and the 1710 interconnect lines , 1730 and 1750 can be formed as the scan lines.
[0436] [0436] The pixels can be arranged in a matrix form, in which the anodes of the light-emitting diodes R, G and B of each pixel are commonly connected to the reflective electrode 1250, and their cathodes are connected to the 1710 interconnect lines , 1730, and 1750 separated from each other. Here, interconnect lines 1710, 1730 and 1750 can be used as Vscan scan lines.
[0437] [0437] FIG. 40 is an enlarged one-pixel plan view of the display device of FIG. 39, FIG. 41 is a schematic cross-sectional view taken along a line A-A of FIG. 40, and FIG. 42 is a schematic cross-sectional view taken along a line B-B of FIG. 40.
[0438] [0438] Referring to FIG. 39, FIG. 40, FIG. 41, and FIG. 42, in each pixel, a portion of the reflective electrode 1250, the ohmic electrode 1290 formed on the top surface of the first battery of LED 1230 (see FIG. 43H), a portion of the second transparent electrode p 1350 (see also FIG. 43H), a portion of the upper surface of the second LED battery 1330 (see FIG. 43J), a portion of the third transparent electrode p 1450 (see FIG. 43H) and the upper surface of the third LED battery 1430 are exposed to the outside.
[0439] [0439] The third LED stack 1430 may have a rough surface 1430a on its top surface. The rough surface 1430a can be formed over the entire upper surface of the third LED stack 1430 or it can be formed in some regions thereof, as shown in FIG. 41.
[0440] [0440] A lower insulation layer 1610 can cover a side surface of each pixel. The lower insulation layer 1610 can be formed from a light transmitting material, such as SiO2. In this case, the lower insulation layer 1610 can cover the entire upper surface of the third LED stack
[0441] [0441] The bottom insulation layer 1610 can include an opening 1610a that exposes the top surface of the third LED stack 1430, an opening 1610b that exposes the top surface of the second LED stack 1330, an opening 1610c (see FIG. 43H) which exposes the ohmic electrode 1290 of the first 1230 LED stack, an opening 1610d that exposes the third transparent electrode 1450, an opening 1610e that exposes the second transparent electrode 1350 and openings 1610f that expose the first reflective electrode p 1250.
[0442] [0442] Interconnect lines 1710 and 1750 can be formed close to the first to third LED batteries 1230, 1330 and 1430 on the support substrate 1510 and can be arranged in the lower insulation layer 1610 to be isolated from the first reflective electrode p 1250 A connection portion 1770a connects the third transparent electrode p 1450 to the reflective electrode 1250 and a connection portion 1770b connects the second transparent electrode p 1350 to the reflective electrode 1250, so that the anodes of the first battery of LED 1230, the second battery of LED 1330 and the third battery of LED 1430 are commonly connected to the reflective electrode 1250.
[0443] [0443] A connection portion 1710a connects the top surface of the third LED stack 1430 to the interconnect line 1710 and a connection portion 1750a connects the ohmic electrode 1290 in the first LED stack 1230 to the interconnect line 1750.
[0444] [0444] An upper insulation layer 1810 can be arranged on interconnect lines 1710 and 1730 and the lower insulation layer 1610 to cover the upper surface of the third stack of LED 1430. The upper insulation layer 1810 can have an opening 1810a that partially exposes the top surface of the second 1330 LED stack.
[0445] [0445] The interconnect line 1730 can be arranged in the upper insulation layer 1810, and the connection portion 1730a can connect the upper surface of the second stack of LED 1330 to the interconnect line 1730. The connection portion 1730a can pass through an upper portion of the interconnect line 1750 and is isolated from the interconnect line 1750 by the upper insulation layer 1810.
[0446] [0446] Although the electrodes of each pixel, according to the exemplary mode illustrated, are described as being connected to the data line and the scan lines, several implementations are possible. Furthermore, although interconnect lines 1710 and 1750 are described as being formed in the lower insulation layer 1610, and interconnect line 1730 is formed in the upper insulation layer 1810, the inventive concepts are not limited to this. For example, each of the interconnection lines 1710, 1730 and 1750 can be formed in the lower insulation layer 1610 and covered by the upper insulation layer 1810, which may have openings to expose the interconnection line 1730. In this structure, the portion of connection 1730a can connect the top surface of the second stack of LED 1330 to the interconnect line 1730 through the openings of the top insulation layer 1810.
[0447] [0447] Alternatively, interconnect lines 1710, 1730 and 1750 can be formed within the supporting substrate 1510, and connection portions 1710a, 1730a and 1750a in the lower insulation layer 1610 can connect the ohmic electrode 1290, the upper surface from the second 1330 LED stack and the top surface of the third 1430 LED stack for the 1710, 1730 and 1750 interconnect lines.
[0448] [0448] FIG. 43A to FIG. 43K are schematic plan views that illustrate a method of manufacturing a display device including the pixel of FIG. 40 according to an exemplary modality.
[0449] [0449] First, the stack of light-emitting diodes 1000 described in FIG. 36 is prepared.
[0450] [0450] Then, with reference to FIG. 43A, a rough surface 1430a can be formed on the top surface of the third LED stack 1430. The rough surface 1430a can be formed on the top surface of the third LED stack 1430, so as to correspond to each pixel region. The rough surface 1430a can be formed by chemical engraving, for example, photo-enhanced chemical engraving (PEC) or the like.
[0451] [0451] The rough surface 1430a can be partially formed in each pixel region taking into account a region of the third LED stack 1430 to be recorded in the subsequent process, without being limited to it. Alternatively, the rough surface 1430a can be formed over the entire upper surface of the third LED stack 1430.
[0452] [0452] Referring to FIG. 43B, a region surrounding the third LED battery 1430 in each pixel is removed by recording to expose the third transparent electrode p 1450. As shown in Fig. 43B, the third LED battery 1430 can remain in a rectangular or square shape. The third stack of LED 1430 may have a plurality of depressions along its edges.
[0453] [0453] Referring to FIG. 43C, the upper surface of the second 1330 LED battery is exposed by removing the third exposed transparent electrode from the third p 1450 in areas other than a depression of the third 1430 LED battery. Therefore, the upper surface of the second 1330 LED battery is exposed around the third stack of LED 1430 and other depressions, excluding the depression in which the third transparent electrode p 1450 remains partially.
[0454] [0454] Referring to FIG. 43D, the second transparent electrode p 1350 is exposed by removing the second exposed 1330 LED battery in areas other than the depression of the third 1430 LED battery.
[0455] [0455] Referring to FIG. 43E, the ohmic electrode 1290 is exposed together with the top surface of the first 1230 LED cell by removing the second transparent electrode p 1350 exposed in areas other than the depression of the third 1430 LED cell. In this case, the 1290 ohmic electrode can be exposed in a depression. Therefore, the upper surface of the first 1230 LED cell is exposed around the third 1430 LED cell and an upper surface of the ohmic electrode 1290 is exposed in at least one of the depressions formed in the third 1430 LED cell.
[0456] [0456] Referring to FIG. 43F, the reflective electrode 1250 is exposed by removing an exposed portion of the first LED battery
[0457] [0457] Referring to FIG. 43G, linear interconnect lines are formed by standardizing the reflective electrode 1250. Here, the supporting substrate 1510 can be exposed. The reflective electrode 1250 can connect pixels arranged in a line with each other between pixels arranged in a matrix (see FIG. 39).
[0458] [0458] Referring to FIG. 43H, a lower insulation layer 1610 (see FIG. 41 and FIG. 42) is formed to cover the pixels. The lower insulation layer 1610 covers the reflective electrode 1250 and the side surfaces of the first to third LED batteries 1230, 1330 and 1430. In addition, the lower insulation layer 1610 can at least partially cover the upper surface of the third LED battery. 1430. If the lower insulation layer 1610 is a transparent layer, such as a SiO2 layer, the lower insulation layer 1610 can cover the entire upper surface of the third stack of LED 1430. Alternatively, when the lower insulation layer 1610 includes a distributed Bragg reflector, the lower insulation layer 1610 can at least partially expose the upper surface of the third LED stack 1430, so that the light can be emitted to the outside.
[0459] [0459] The bottom insulation layer 1610 may include an opening 1610a that exposes the third battery of LED 1430, an opening 1610b that exposes the second battery of LED 1330, an opening 1610c that exposes the ohmic electrode 1290, an opening 1610d that exposes the third transparent electrode p 1450, an opening 1610e that exposes the second transparent electrode p 1350 and an opening 1610f that exposes the reflective electrode 1250. One or more openings 1610f can be formed to expose the reflective electrode 1250.
[0460] [0460] Referring to FIG. 43I, interconnect lines 1710, 1750 and connecting parts 1710a, 1750a, 1770a and 1770b are formed. These can be formed by a lifting process or the like. Interconnect lines 1710 and 1750 are isolated from reflective electrode 1250 by lower insulation layer 1610. Connection portion 1710a electrically connects the third LED stack 1430 to interconnect line 1710, and connection portion 1750a electrically connects the ohmic electrode 1290 to the 1750 interconnect line, so that the first 1230 LED stack is electrically connected to the interconnect line
[0461] [0461] Referring to FIG. 43J, an upper insulation layer 1810 (see FIG. 41 and FIG. 42) covers interconnect lines 1710 and 1750 and connection parts 1710a, 1750a, 1770a and 1770b. The top insulation layer 1810 can also cover the entire top surface of the third LED stack
[0462] [0462] Referring to FIG. 43K, an interconnect line 1730 and a connection portion 1730a are formed. An interconnect line 1750 and a connection portion 1750a can be formed by a lifting process or the like. Interconnect line 1730 is arranged in the upper insulation layer 1810 and is isolated from reflective electrode 1250 and interconnect lines 1710 and 1750. Connection portion 1730a electrically connects the second stack of LED 1330 to interconnect line 1730. The portion connection cable 1730a can pass through an upper portion of interconnect line 1750 and is isolated from interconnect line 1750 by the upper insulation layer
[0463] [0463] As such, a pixel region as shown in FIG. 40 can be formed. In addition, as shown in FIG. 39, a plurality of pixels can be formed on the support substrate 1510 and can be connected to each other by the first reflective electrode p 1250 and the interconnect lines 1710, 1730 and 1750 to be operated in a passive matrix manner.
[0464] [0464] Although the display device above has been described as being configured to be operated in the passive matrix manner, the inventive concepts are not limited to these. More particularly, a display device according to some exemplary embodiments can be manufactured in a number of ways, so as to be operated in the passive matrix manner using the stack of light-emitting diodes shown in FIG. 36.
[0465] [0465] For example, although interconnect line 1730 is shown to be formed in the upper insulation layer 1810, interconnect line 1730 can be formed together with interconnect lines 1710 and 1750 in the lower insulation layer 1610 and the upper part. connection cable 1730a can be formed in the upper insulation layer 1810 to connect the second stack of LED 1330 to the interconnect line 1730. Alternatively, the interconnect lines 1710, 1730 and 1750 can be arranged within the support substrate 1510.
[0466] [0466] FIG. 44 is a schematic circuit diagram of a display device according to another exemplary embodiment. The display device, according to the exemplary mode illustrated, can be operated in an active matrix manner.
[0467] [0467] Referring to FIG. 44, the drive circuit according to an exemplary embodiment includes at least two transistors Tr1, Tr2 and a capacitor. When a power source is connected to the selection lines Vrow1 to Vrow3 and the voltage is applied to the data lines Vdata1 to Vdata3, the voltage is applied to the corresponding LED. In addition, the corresponding capacitor is charged according to the values of Vdata1 to Vdata3. Since the activation state of a transistor Tr2 can be maintained by the charged voltage of the capacitor, the voltage of the capacitor can be maintained and applied to the light-emitting cells of LED1, LED3 and LED3, even when the power supply to Vrow1 is turned off. In addition, the electric current flowing in the light emitting diodes LED1 to LED3 can be changed depending on the values from Vdata1 to Vdata3. The electric current can be supplied continuously through the Vdd, so that the light can be emitted continuously.
[0468] [0468] Transistors Tr1, Tr2 and capacitor can be formed within the supporting substrate 1510. For example, thin film transistors formed on a silicon substrate can be used to drive the active matrix.
[0469] [0469] The light emitting diodes LED1 to LED3 can correspond to the first to third batteries of LED 1230, 1330 and 1430 stacked in one pixel, respectively. The anodes from the first to the third LED cells are connected to transistor Tr2 and their cathodes are connected to ground.
[0470] [0470] Although FIG. 44 show the circuit for activating the active matrix, according to an exemplary modality, other various types of circuits can be used. In addition, although the anodes of the light-emitting diodes LED1 to LED3 are described as being connected to different Tr2 transistors, and their cathodes are described as being connected to ground, the inventive concepts are not limited to these and the anodes of the light-emitting diodes can be connected to Vdd current sources and their cathodes can be connected to different transistors.
[0471] [0471] FIG. 45 is a schematic one-pixel plan view of a display device according to another exemplary embodiment. The pixel described herein can be one of a plurality of pixels arranged on the support substrate 1511.
[0472] [0472] Referring to FIG. 45, the pixels according to an exemplary embodiment are generally similar to the pixels described with reference to FIG. 39 through FIG. 42, except that the supporting substrate 1511 is a thin film transistor panel, including transistors and capacitors, and the reflecting electrode is disposed in a lower region of the first LED stack.
[0473] [0473] The cathode of the third LED stack is connected to the support substrate 1511 through the connection portion 1711a. For example, as shown in FIG. 45, the cathode of the third LED stack can be connected to the ground via the electrical connection to the supporting substrate 1511. The cathodes of the second LED stack and the first LED stack can also be connected to the ground via an electrical connection to the support substrate. support 1511 through connection portions 1731a and 1751a.
[0474] [0474] The reflective electrode is connected to the transistors Tr2 (see FIG. 44) inside the support substrate 1511. The third transparent electrode p and the second transparent electrode p are also connected to the transistors Tr2 (see FIG. 44) inside the substrate of support 1511 through connection portions 1771a and 1731b.
[0475] [0475] In this way, the first to the third LED batteries are connected to each other, thus constituting a circuit for activating the active matrix, as shown in FIG. 44.
[0476] [0476] Although FIG. 45 show the electrical connection of a pixel for activating the active matrix, according to an exemplary modality, the inventive concepts are not limited to these, and the circuit for the display device can be modified in several circuits for activating the active matrix of many ways.
[0477] [0477] Furthermore, while the reflective electrode 1250, the second transparent electrode p 1350 and the third transparent electrode p 1450 of FIG. 36 are described as forming ohmic contact with the corresponding p-type semiconductor layer of each of the first 1230 LED batteries, the second 1330 LED battery and the third 1430 LED battery, and the 1290 ohmic electrode forms ohmic contact with the layer type n semiconductor of the first 1230 LED cell, the type n semiconductor layer of each of the second 1330 LED cells and the third 1430 LED cell is not provided with a separate ohmic contact layer. When the pixels are small in size of 200 µm or less, there is less difficulty in propagating the current, even without the formation of a separate ohmic contact layer in the n-type semiconductor layer. However, according to some exemplary modalities, a transparent electrode layer can be arranged on the type n semiconductor layer of each of the LED cells, in order to guarantee the current propagation.
[0478] [0478] Furthermore, although the first to the third LED batteries 1230, 1330 and 1430 are coupled together by means of the connecting layers 1530, 1550 and 1570, the inventive concepts are not limited to these and the first to the third batteries of LEDs 1230, 1330, and 1430 can be connected to each other in various sequences and using various structures.
[0479] [0479] According to exemplary modalities, since it is possible to form a plurality of pixels at the wafer level using the stack of light emitting diodes 1000 for a display, the individual assembly of light emitting diodes can be avoided. In addition, the stack of light emitting diodes according to the exemplary modalities has the structure in which the first to the third 1230, 1330 and 1430 LED batteries are stacked in the vertical direction, thus ensuring an area for sub-pixels in a limited area of pixels. In addition, the battery of light emitting diodes according to the exemplary modalities allows the light generated from the first 1230 LED battery, the second 1330 LED battery and the third 1430 LED battery to be emitted out of it, reducing thus the loss of light.
[0480] [0480] FIG. 46 is a schematic cross-sectional view of a stack of LEDs for a display in accordance with an exemplary embodiment.
[0481] [0481] Referring to FIG. 46, the stack of light emitting diodes 2000 includes a support substrate 2510, a first stack of LED 2230, a second stack of LED 2330, a third stack of LED 2430, a reflective electrode 2250, an ohmic electrode 2290, a second transparent electrode 2350, a third transparent electrode p 2450, an insulation layer 2270, a first connection layer 2530, a second connection layer 2550 and a third layer of connection 2570. In addition, the first stack of LED 2230 may include a ohmic contact portion 2230a for ohmic contact.
[0482] [0482] In general, light can be generated from the first LED battery by the light emitted by the second LED battery and light can be generated from the second LED battery by the light emitted by the third LED battery. As such, a color filter can be interposed between the second LED battery and the first LED battery and between the third LED battery and the second LED battery.
[0483] [0483] However, while color filters can prevent light interference, the formation of color filters increases the complexity of manufacturing. A display device in accordance with exemplary modalities can suppress the generation of secondary light between the LED batteries without the provision of color filters between them.
[0484] [0484] Therefore, in some exemplary embodiments, the interference of light between the LED cells can be reduced by controlling the bandwidth of each of the LED cells, which will be described in more detail below.
[0485] [0485] The support substrate 2510 supports semiconductor cells 2230, 2330 and 2430. The support substrate 2510 may include a circuit on a surface of the same or in it, but the inventive concepts are not limited to it. The support substrate 2510 can include, for example, a Si substrate, a Ge substrate, a sapphire substrate, a standardized sapphire substrate, a glass substrate or a standardized glass substrate.
[0486] [0486] Each of the first 2230 LED stack, the second 2330 LED stack and the 2430 LED stack includes a n-type semiconductor layer, a p-type semiconductor layer and an active layer interposed between them. The active layer can have a multi-quantum well structure.
[0487] [0487] L1 light generated from the first 2230 LED cell has a longer wavelength than L2 light generated from the second 2330 LED cell, which has a longer wavelength than the L3 light generated at from the third 2430 LED battery. However, the inventive concepts are limited to these and, when the light emitting diode battery includes micro LEDs, the light generated from the first, second and third LED batteries 2230, 2330 and 2440 can have any wavelength range without adversely affecting the operation due to its small form factor.
[0488] [0488] The first battery of 2230 LEDs can be an inorganic light emitting diode configured to emit red light, the second battery of 2330 LEDs can be an inorganic light emitting diode configured to emit green light and the third battery of 2430 LEDs can be an inorganic light emitting diode configured to emit blue light. The first 2230 LED stack can include a GaInP based well layer, and each of the second 2330 LED stack and the third 2430 LED stack can include a GaInN based well layer.
[0489] [0489] Although the stack of light emitting diodes 2000 of FIG. 46 is illustrated as including three LED batteries 2230, 2330 and
[0490] [0490] Both surfaces of each of the first to third LED batteries 2230, 2330 and 2430 are a n-type semiconductor layer and a p-type semiconductor layer, respectively. In FIG. 46, each from the first to the third stack of LEDs 2230, 2330 and 2430 is described as having an upper surface of type n and a lower surface of type p. Since the third 2430 LED stack has a top surface of type n, a rough surface can be formed on the top surface of the third 2430 LED stack through chemical etching or the like. However, the inventive concepts are not limited to them, and the types of semiconductors on the top and bottom surfaces of each of the LED cells can be formed alternatively.
[0491] [0491] The first 2230 LED battery is placed close to the support substrate 2510, the second 2330 LED battery is located on the first 2230 LED battery and the third 2430 LED battery is placed on the second LED battery. As the first 2230 LED battery emits light with a longer wavelength than the second and third 2330 and 2430 LED batteries, the L1 light generated from the first 2230 LED battery can be emitted to the outside by the second and third 2330 and 2430 LED batteries. In addition, since the second 2330 LED battery emits light with a longer wavelength than the third 2430 LED battery, the L2 light generated from the second 2330 LED battery can be emitted to the outside through the third LED battery
[0492] [0492] In an exemplary embodiment, the n-type semiconductor layer of the first 2230 LED stack can have a band gap greater than the band gap of the active layer of the first 2230 LED stack and narrower than the band gap of the first 2230 LED stack. active layer of the second 2330 LED stack. Therefore, a portion of light generated from the second 2330 LED stack can be absorbed by the n-type semiconductor layer of the first 2230 LED stack before reaching the active layer of the first 2330 LED stack. LED 2230. As such, the intensity of the light generated in the active layer of the first battery of LED 2230 can be reduced by the light generated from the second battery of LED 2330.
[0493] [0493] In addition, the n-type semiconductor layer of the second 2330 LED stack has a bandwidth greater than the active layer bandwidth of each of the first 2230 LED cells and the second 2330 LED stack and more narrower than the band gap of the active layer of the third 2430 LED stack. Therefore, a portion of light generated from the third 2430 LED stack can be absorbed by the n-type semiconductor layer of the second 2330 LED stack before reaching the active layer of the second 2330 LED battery. As such, the intensity of the light generated in the second 2330 LED battery or the first 2230 LED battery can be reduced by the light generated from the third 2430 LED battery.
[0494] [0494] The p-type semiconductor layer and the n-type semiconductor layer of the third 2430 LED stack have wider band intervals than the active layers of the first 2230 LED stack and the second 2330 LED stack, thus transmitting the generated light by the first and second LED batteries 2230 and 2330 through them.
[0495] [0495] According to an exemplary modality, it is possible to reduce the interference of light between the 2230, 2330 and 2430 LED cells by adjusting the band intervals of the type n semiconductor layers or the type p semiconductor layers of the first and second cells LEDs 2230 and 2330, which can avoid the need for other components, such as color filters. For example, the light intensity generated from the second 2330 LED battery and emitted to the outside can be about 10 times or more than the light intensity generated from the first 2230 LED battery by the light generated from the second 2330 LED battery. Likewise, the intensity of light generated from the third 2430 LED battery and emitted to the outside can be about 10 times or more the light intensity generated from the second 2330 LED battery caused by light generated from the third stack of LED 2430. In this case, the intensity of light generated from the third stack of LED 2430 and emitted to the outside can be about 10 times or more the intensity of the light generated from the first stack 2230 LED light caused by the light generated from the third 2430 LED battery It is therefore possible to create a display device free from color contamination caused by light interference.
[0496] [0496] The reflective electrode 2250 forms ohmic contact with the p-type semiconductor layer of the first 2230 LED cell and reflects the light generated from the first 2230 LED cell. For example, the reflective electrode 2250 may include a contact layer ohmic 2250a and a reflective layer 2250b.
[0497] [0497] The ohmic contact layer 2250a partially contacts the p-type semiconductor layer of the first 2230 LED stack. To prevent light absorption by the ohmic contact layer
[0498] [0498] Since the reflective layer 2250b covers the insulation layer 2270, an omnidirectional reflector can be formed by the stacked structure of the first 2230 LED stack with a relatively high refractive index and the 2270 insulation layer with a refractive index. relatively low, and the reflective layer 2250b. The reflective layer 2250b can cover about 50% or more of the area of the first 2230 LED battery or most of the first 2230 LED battery, thus improving luminous efficiency.
[0499] [0499] The ohmic contact layer 2250a and the reflective layer 2250b can be formed by layers of metal, which can include Au. The reflective layer 2250b can include metal with a relatively high reflectance in relation to the light generated from the first 2230 LED stack, for example, red light. On the other hand, the reflective layer 2250b can include metal with relatively low reflectance in relation to the light generated from the second stack of LED 2330 and the third stack of LED 2430, for example, green light or blue light, to reduce interference from light. generated from the second and third LED batteries 2330, 2430 and traveling towards the support substrate 2510.
[0500] [0500] The insulation layer 2270 is interposed between the support substrate 2510 and the first 2230 LED stack and has openings that expose the first 2230 LED stack. The ohmic contact layer 2250a is connected to the first 2230 LED stack in the 2270 insulation layer openings.
[0501] [0501] The ohmic electrode 2290 is disposed on the top surface of the first 2230 LED battery. In order to reduce the ohmic contact resistance of the ohmic electrode 2290, the ohmic contact portion 2230a may protrude from the upper surface of the first 2230 LED battery. The ohmic electrode 2290 can be arranged in the ohmic contact portion 2230a.
[0502] [0502] The second transparent p 2350 electrode forms ohmic contact with the p type semiconductor layer of the second 2330 LED stack. The second transparent p 2350 electrode can be formed by a metal layer or a conductive oxide layer that is transparent to the red light and green light.
[0503] [0503] The third p 2450 transparent electrode forms ohmic contact with the p p semiconductor layer of the third 2430 LED stack. The third p 2450 transparent electrode can be formed by a metal layer or a conductive oxide layer that is transparent to the red light, green light and blue light.
[0504] [0504] The reflective electrode 2250, the second transparent electrode p 2350 and the third transparent electrode p 2450 can assist in the propagation of current through the ohmic contact with the p-type semiconductor layer of the corresponding LED cells.
[0505] [0505] The first link layer 2530 couples the first stack of LED 2230 to the support substrate 2510. As shown in Fig. 46, the reflective electrode 2250 can join with the first link layer 2530. The first link layer 2530 it can be a transmissive layer or opaque to light.
[0506] [0506] The second layer of connection 2550 couples the second battery of LED 2330 to the first battery of LED 2230. As shown in Fig. 46, the second layer of connection 2550 can join the first battery of LED 2230 and the second transparent electrode p 2350. The ohmic electrode 2290 can be covered by the second connection layer 2550. The second connection layer 2550 transmits light generated from the first stack of LED 2230. The second connection layer 2550 can be formed from a transmitting connection material light, for example, a light-transmitting organic binding agent or light-transmitting spin-on-glass. Examples of the light-transmitting organic binding agent can include SU8, poly (methyl methacrylate) (PMMA), polyimide, Parylene, benzocyclobutene (BCB) and the like. In addition, the second 2330 LED battery can be connected to the first 2230 LED battery by plasma connection or the like.
[0507] [0507] The third layer of connection 2570 couples the third battery of LED 2430 to the second battery of LED 2330. As shown in Fig. 46, the third layer of connection 2570 can join the second battery of LED 2330 and the third electrode transparent p
[0508] [0508] Each of the second link layer 2550 and the third link layer 2570 can transmit light generated from the third stack of LED 2430 and light generated from the second stack of LED 2330.
[0509] [0509] FIG. 47A to FIG. 47E are schematic cross-sectional views illustrating a method of fabricating a stack of light-emitting diodes for a display in accordance with an exemplary embodiment.
[0510] [0510] Referring to FIG. 47A, a first 2230 LED stack is grown on a first 2210 substrate. The first 2210 substrate can be, for example, a GaAs substrate. The first 2230 LED stack consists of semiconductor layers based on AlGaInP and includes a n-type semiconductor layer, an active layer and a p-type semiconductor layer. In some exemplary embodiments, the n-type semiconductor layer may have an energy gap capable of absorbing the light generated from the second 2330 LED stack and the p-type semiconductor layer may have an energy gap capable of absorbing the generated light. from the second 2330 LED battery.
[0511] [0511] An insulating layer 2270 is formed in the first stack of LEDs 2230 and standardized to form openings in it. For example, a SiO2 layer is formed on the first 2230 LED stack and a photoresistor is deposited on the SiO2 layer, followed by photolithography and development to form a photoresistor pattern. Then, the SiO2 layer is standardized through the photoresistor pattern used as a recording mask, thus forming the 2270 insulation layer having the openings.
[0512] [0512] Then, a layer in ohmic contact 2250a is formed in the openings of the insulation layer 2270. The layer in ohmic contact 2250a can be formed by a lifting process or the like. After the ohmic contact layer 2250a is formed, a reflective layer 2250b is formed to cover the ohmic contact layer 2250a and the insulating layer 2270. The reflective layer 2250b can be formed by a lifting process or the like. The reflective layer 2250b can cover a portion of the ohmic contact layer 2250a or all of it. The ohmic contact layer 2250a and the reflective layer 2250b form a reflective electrode 2250.
[0513] [0513] The reflective electrode 2250 forms ohmic contact with the p-type semiconductor layer of the first 2230 LED stack and, therefore, will be hereinafter referred to as a first reflective electrode p 2250.
[0514] [0514] Referring to FIG. 47B, a second 2330 LED stack is grown on a second 2310 substrate and a second transparent p 2350 electrode is formed on the second 2330 LED stack. The second 2330 LED stack can be formed by GaN-based semiconductor layers and may include a layer of GaInN well. The second substrate 2310 is a substrate on which the GaN-based semiconductor layers can be grown on it and is different from the first 2210 substrate. The composition ratio of GaInN to the second 2330 LED stack can be determined so that the second 2330 LED battery emit green light. The second transparent p 2350 electrode forms ohmic contact with the p-type semiconductor layer of the second 2330 LED cell. The second 2330 LED cell may include an n-type semiconductor layer, an active layer and a p-type semiconductor layer. In some exemplary embodiments, the n-type semiconductor layer of the second 2330 LED cell may have an energy band gap capable of absorbing the light generated from the third 2430 LED cell, and the p-type semiconductor layer of the second cell 2330 LED can have an energy range capable of absorbing the light generated from the third 2430 LED stack.
[0515] [0515] Referring to FIG. 47C, a third stack of LED 2430 is grown on a third substrate 2410 and a third transparent electrode p 2450 is formed on the third stack of LED 2430. The third stack of LED 2430 can be formed of semiconductor layers based on GaN and may include a GaInN well layer. The third substrate 2410 is a substrate on which the GaN-based semiconductor layers can be grown on it and is different from the first 2210 substrate. The GaInN composition ratio for the third 2430 LED stack can be determined so that the third stack LED light emits blue light. The third p 2450 transparent electrode forms ohmic contact with the p-type semiconductor layer of the third 2430 LED battery.
[0516] [0516] As such, the first stack of LED 2230, the second stack of LED 2330 and the third stack of LED 2430 are grown on different substrates, and the sequence of their formation is not limited to a specific sequence.
[0517] [0517] Referring to FIG. 47D, the first 2230 LED stack is coupled to the support substrate 2510 through a first connection layer 2530. The first connection layer 2530 can be formed previously on the support substrate 2510 and the reflective electrode 2250 can be connected to the first layer connector 2530 to face the support substrate 2510. The first substrate 2210 is removed from the first stack of LED 2230 by chemical etching or the like. Therefore, the upper surface of the n-type semiconductor layer of the first 2230 LED stack is exposed.
[0518] [0518] Then, a 2290 ohmic electrode is formed in the exposed region of the first 2230 LED stack. In order to reduce the ohmic contact resistance of the 2290 ohmic electrode, the 2290 ohmic electrode can be heat treated. The ohmic electrode 2290 can be formed in each pixel region,
[0519] [0519] Referring to FIG. 47E, the second LED battery 2330 is coupled to the first LED battery 2230, in which the ohmic electrode 2290 is formed, through a second connection layer 2550. The second transparent electrode p 2350 is connected to the second connection layer 2550 to face the first stack of LED 2230. The second layer of connection 2550 can be formed previously in the first stack of LED 2230, so that the second transparent electrode p 2350 can be turned over and connected to the second layer of connection 2550. The second substrate 2310 can be separated from the second 2330 LED battery by a laser lifting or chemical lifting process.
[0520] [0520] Then, with reference to FIG. 46 and FIG. 47C, the third battery of LED 2430 is coupled to the second battery of LED 2330 through a third layer of connection 2570. The third transparent electrode p 2450 is connected to the third layer of connection 2570 to face the second battery of LED 2330. The third connection layer 2570 can be formed previously on the second stack of LED 2330, so that the third transparent electrode p 2450 can be turned and connected to the third connection layer
[0521] [0521] A display device can be formed by standardizing the stack of the first to the third LED batteries 2230, 2330 and 2430 arranged on the support substrate 2510 in pixel units, followed by the connection of the first to the third battery of
[0522] [0522] FIG. 48 is a schematic circuit diagram of a display device according to an exemplary embodiment. FIG. 49 is a schematic plan view of a display device according to an exemplary embodiment.
[0523] [0523] Referring to FIG. 48 and FIG. 49, the display device, according to an exemplary modality, can be implemented to be operated in a passive matrix manner.
[0524] [0524] The stack of light emitting diodes for a display shown in FIG. 46 has the structure including the first to the third LED batteries 2230, 2330 and 2430 stacked in the vertical direction. As a pixel includes three light-emitting diodes R, G and B, a first light-emitting diode R can correspond to the first LED stack 2230, a second light-emitting diode G can correspond to the second LED stack 2330 and a third diode light emitter B can correspond to the third LED battery
[0525] [0525] Referring to FIGS. 48 and 49, a pixel includes the first to third light emitting diodes R, G and B, each of which may correspond to a sub-pixel. The anodes of the first to the third light-emitting diodes R, G and B are connected to a common line, for example, a data line and their cathodes are connected to different lines, for example, scanning lines. For example, in a first pixel, the anodes from the first to the third light-emitting diodes R, G and B are commonly connected to a Vdata1 data line and their cathodes are connected to the Vscan1-1, Vscan1-2 scan lines, and Vscan1-3, respectively. As such, the light emitting diodes R, G and B at each pixel can be activated independently.
[0526] [0526] In addition, each of the light-emitting diodes R, G and B can be triggered by a pulse width modulation or by changing the magnitude of the electrical current to control the brightness of each subpixel.
[0527] [0527] Referring to FIG. 49, a plurality of pixels are formed by patterning the stack of FIG. 46, and each of the pixels is connected to the reflective electrodes 2250 and the interconnecting lines 2710, 2730 and 2750. As shown in Fig. 48, the reflective electrode 2250 can be used as the Vdata data line and the 2710 interconnect lines. , 2730 and 2750 can be formed as the scan lines.
[0528] [0528] The pixels can be arranged in a matrix form, in which the anodes of the light-emitting diodes R, G and B of each pixel are commonly connected to the reflective electrode 2250, and their cathodes are connected to the interconnecting lines 2710 , 2730, and 2750 separated from each other. Here, interconnect lines 2710, 2730 and 2750 can be used as Vscan scan lines.
[0529] [0529] FIG. 50 is an enlarged one-pixel plan view of the display device of FIG. 49. FIG. 51 is a schematic cross-sectional view taken along a line A-A of FIG. 50, and FIG. 52 is a schematic cross-sectional view taken along a line B-B of FIG. 50.
[0530] [0530] Referring to FIGS. 49 to 52, at each pixel, a portion of the reflective electrode 2250, the ohmic electrode 2290 formed on the top surface of the first 2230 LED battery (see FIG. 53H), a portion of the second transparent electrode p 2350 (see FIG. 53H) , a portion of the upper surface of the second LED battery 2330 (see FIG. 53J), a portion of the third transparent electrode p 2450 (see FIG. 53H) and the upper surface of the third LED battery 2430 are exposed to the outside.
[0531] [0531] The third 2430 LED battery may have a rough surface 2430a on its upper surface. The rough surface 2430a can be formed over the entire upper surface of the third LED stack 2430 or it can be formed in some regions of it.
[0532] [0532] A lower insulation layer 2610 can cover a side surface of each pixel. The lower insulation layer 2610 can be formed from a light transmitting material, such as SiO2. In this case, the bottom insulation layer 2610 can substantially cover the entire top surface of the third 2430 LED stack. Alternatively, the bottom insulation layer 2610 may include a Bragg reflector distributed to reflect the light traveling towards the side surfaces of the first to third batteries of LEDs 2230, 2330 and 2430. In this case, the lower insulation layer 2610 may partially expose the upper surface of the third battery of LED 2430. Alternatively, the lower insulation layer 2610 may be an insulating layer to the black base that absorbs light. In addition, an electrically floating reflective metallic layer can also be formed in the lower insulation layer 2610 to reflect the light emitted through the side surfaces of the first to third LED batteries 2230, 2330 and 2430.
[0533] [0533] The bottom insulation layer 2610 may include an opening 2610a that exposes the top surface of the third LED stack 2430, an opening 2610b that exposes the top surface of the second LED stack 2330, an opening 2610c (see FIG. 53H) which exposes the ohmic electrode 2290 of the first stack of LED 2230, an opening 2610d that exposes the third transparent electrode 2450, an opening 2610e that exposes the second transparent electrode 2350 and openings 2610f that expose the first reflective electrode p 2250.
[0534] [0534] The interconnection lines 2710 and 2750 can be formed near the first to the third batteries of LEDs 2230, 2330 and 2430 on the support substrate 2510 and can be arranged in the lower insulation layer 2610 to be isolated from the first reflective electrode 2250. A connection portion 2770a connects the third transparent electrode p 2450 to the reflective electrode 2250 and a connection portion 2770b connects the second transparent electrode p 2350 to the reflective electrode 2250, so that the anodes of the first battery of LED 2230, the second battery of LED 2330 and the third stack of LED 2430 are commonly connected to the reflective electrode 2250.
[0535] [0535] A connection portion 2710a connects the top surface of the third 2430 LED stack to the interconnect line 2710 and a connection portion 2750a connects the ohmic electrode 2290 on the first 2230 LED stack to the interconnect line 2750.
[0536] [0536] An upper insulation layer 2810 can be arranged on the interconnect lines 2710 and 2730 and the lower insulation layer 2610 to cover the upper surface of the third 2430 LED stack. The upper insulation layer 2810 may have an opening 2810a that partially exposes the top surface of the second 2330 LED stack.
[0537] [0537] The interconnect line 2730 can be arranged in the upper insulation layer 2810, and the connection portion 2730a can connect the upper surface of the second stack of LED 2330 to the interconnect line 2730. The connection portion 2730a can pass through an upper portion of the interconnect line 2750 and is isolated from the interconnect line 2750 by the upper insulation layer 2810.
[0538] [0538] Although the electrodes of each pixel are described as connected to the data line and the scan lines, the inventive concepts are not limited to these. In addition, while interconnect lines 2710 and 2750 are described as being formed in the lower insulation layer 2610 and interconnect line 2730 is described as being formed in the upper insulation layer 2810, the inventive concepts are not limited to these. For example, all interconnect lines 2710, 2730 and 2750 can be formed in the lower insulation layer 2610 and can be covered by the upper insulation layer 2810, which may have openings that expose the interconnect line 2730. In this way, the portion connector 2730a can connect the upper surface of the second 2330 LED stack to the interconnect line 2730 through the openings of the upper insulation layer 2810.
[0539] [0539] Alternatively, interconnect lines 2710, 2730 and 2750 can be formed within the support substrate 2510, and connection portions 2710a, 2730a and 2750a in the lower insulation layer 2610 can connect the ohmic electrode 2290, the upper surface of the first 2230 LED stack and the top surface of the third 2430 LED stack for the interconnect lines 2710, 2730 and 2750.
[0540] [0540] According to an exemplary modality, the L1 light generated from the first 2230 LED battery is emitted to the outside through the second and third 2330 and 2430 LED batteries,
[0541] [0541] FIG. 53A to FIG. 53K are schematic plan views that illustrate a method of manufacturing a display device according to an exemplary embodiment. In the following, the following descriptions will be given with reference to the pixel of FIG. 50.
[0542] [0542] First, the stack of light emitting diodes 2000 described in FIG. 46 is prepared.
[0543] [0543] Referring to FIG. 53A, a rough surface 2430a can be formed on the top surface of the third LED stack
[0544] [0544] The rough surface 2430a can be partially formed in each pixel region taking into account a region of the third stack of LED 2430 to be recorded in the subsequent process, without being limited to it. Alternatively, the rough surface 2430a can be formed over the entire upper surface of the third LED stack 2430.
[0545] [0545] Referring to FIG. 53B, a region surrounding the third 2430 LED battery in each pixel is removed by recording to expose the third transparent electrode p 2450. As shown in Fig. 53B, the third 2430 LED battery can remain in a rectangular or square shape. The third stack of LED 2430 may have a plurality of depressions formed along its edges.
[0546] [0546] Referring to FIG. 53C, the upper surface of the second 2330 LED battery is exposed by removing the third transparent electrode p 2450 exposed in areas other than a depression. Therefore, the upper surface of the second LED battery 2330 is exposed around the third LED battery 2430 and in depressions other than the depression in which the third transparent electrode p 2450 remains partially.
[0547] [0547] Referring to FIG. 53D, the second transparent p 2350 electrode is exposed by removing the second exposed 2330 LED battery in areas other than a depression.
[0548] [0548] Referring to FIG. 53E, ohmic electrode 2290 is exposed along with the top surface of the first 2230 LED battery by removing the second exposed transparent electrode p 2350 in areas other than a depression. Here, the ohmic electrode 2290 can be exposed in a depression. Accordingly, the upper surface of the first 2230 LED battery is exposed around the third 2430 LED battery and an upper surface of the 2290 ohmic electrode is exposed in at least one of the depressions formed in the third 2430 LED battery.
[0549] [0549] Referring to FIG. 53F, the reflective electrode 2250 is exposed by removing an exposed portion of the first 2230 LED battery in areas other than a depression. As such, the reflective electrode 2250 is exposed around the third LED stack 2430.
[0550] [0550] Referring to FIG. 53G, linear interconnect lines are formed by standardizing the reflective electrode 2250. Here, the support substrate 2510 can be exposed. The reflective electrode 2250 can connect pixels arranged in a line with each other between pixels arranged in a matrix (see FIG. 49).
[0551] [0551] Referring to FIG. 53H, a lower insulation layer 2610 (see FIG. 51 and FIG. 52) is formed to cover the pixels. The lower insulation layer 2610 covers the reflective electrode 2250 and the side surfaces of the first to third LED batteries 2230, 2330 and 2430. In addition, the lower insulation layer 2610 can partially cover the upper surface of the third LED battery 2430. If the bottom insulation layer 2610 is a transparent layer, such as a SiO2 layer, the bottom insulation layer 2610 can cover substantially the entire upper surface of the third 2430 LED stack. Alternatively, the bottom insulation layer 2610 may include a reflector Bragg distributed. In this case, the lower insulation layer 2610 can partially expose the upper surface of the third LED stack 2430 to allow light to be emitted to the outside.
[0552] [0552] The bottom insulation layer 2610 may include an opening 2610a that exposes the third battery of LED 2430, an opening 2610b that exposes the second battery of LED 2330, an opening 2610c that exposes the ohmic electrode 2290, an opening 2610d that exposes the third transparent electrode p 2450, an opening 2610e that exposes the second transparent electrode p 2350 and an opening 2610f that exposes the reflective electrode 2250. The opening 2610f that exposes the reflective electrode 2250 can be formed singularly or plurally.
[0553] [0553] Referring to FIG. 53I, interconnection lines 2710 and 2750 and connection parts 2710a, 2750a, 2770a and 2770b are formed by a lifting process or the like. The interconnect lines 2710 and 2750 are isolated from the reflective electrode 2250 by the lower insulation layer 2610. The connection portion 2710a electrically connects the third LED stack 2430 to the interconnect line 2710, and the connection portion 2750a electrically connects the ohmic electrode. 2290 to interconnect line 2750, so that the first stack of LED 2230 is electrically connected to interconnect line 2750. The connection portion 2770a electrically connects the third transparent electrode p 2450 to the first reflective electrode 2250 and the connection portion 2770b connects electrically the second transparent electrode p 2350 to the first reflective electrode 2250.
[0554] [0554] Referring to FIG. 53J, an upper insulation layer 2810 (see FIG. 51 and FIG. 52) covers interconnect lines 2710, 2750 and connection parts 2710a, 2750a, 2770a and 2770b. The top insulation layer 2810 can also substantially cover the entire top surface of the third 2430 LED stack. The top insulation layer 2810 has an opening 2810a that exposes the top surface of the second 2330 LED stack. The top insulation layer 2810 can be formed, for example, by silicon oxide or silicon nitride and may include a distributed Bragg reflector. When the top insulation layer 2810 includes the distributed Bragg reflector, the top insulation layer 2810 can expose at least part of the top surface of the third 2430 LED stack to allow light to be emitted to the outside.
[0555] [0555] Referring to FIG. 53K, an interconnect line 2730 and a connection portion 2730a are formed. An interconnect line 2750 and a connection portion 2750a can be formed by a lifting process or the like. The interconnect line 2730 is arranged in the upper insulating layer 2810 and is isolated from the reflective electrode 2250 and interconnect lines 2710 and 2750. The connection portion 2730a electrically connects the second battery of LED 2330 to the interconnect line 2730. The portion connection cable 2730a can pass through an upper portion of the interconnect line 2750 and is isolated from the interconnect line 2750 by the upper insulation layer
[0556] [0556] As such, a pixel region shown in FIG. 50 can be formed. In addition, as shown in FIG. 49, a plurality of pixels can be formed on the support substrate 2510 and can be connected to each other by the first reflective electrode p 2250 and the interconnect lines 2710, 2730 and 2750, to be operated in a passive matrix manner.
[0557] [0557] Although the above describes a method of manufacturing a display device that can be operated in the passive matrix manner, the inventive concepts are not limited to these. More particularly, the display device according to exemplary embodiments can be manufactured in a number of ways, so as to be operated in the passive matrix manner using the stack of light-emitting diodes shown in FIG. 46.
[0558] [0558] For example, while interconnect line 2730 is described as being formed in the upper insulation layer 2810, interconnect line 2730 can be formed in conjunction with interconnection lines 2710 and 2750 in the lower insulation layer 2610 and the connection part 2730a can be formed in the upper insulation layer 2810 to connect the second stack of LED 2330 to the interconnect line 2730. Alternatively, the interconnect lines 2710, 2730, 2750 can be arranged within the supporting substrate 2510.
[0559] [0559] FIG. 54 is a schematic circuit diagram of a display device according to another exemplary embodiment. The circuit diagram of FIG. 54 refers to a display device activated in an active matrix manner.
[0560] [0560] Referring to FIG. 54, the drive circuit according to an exemplary embodiment includes at least two transistors Tr1, Tr2 and a capacitor. When a power source is connected to the selection lines Vrow1 to Vrow3 and the voltage is applied to the data lines Vdata1 to Vdata3, the voltage is applied to the corresponding LED. In addition, the corresponding capacitors are charged according to the values from Vdata1 to Vdata3. As the activation state of transistor Tr2 can be maintained by the charged voltage of the capacitor, the voltage of the capacitor can be maintained and applied to the light-emitting cells of LED1, LED3 and LED3, even when the power supply to Vrow1 is turned off. In addition, the electric current flowing in the light emitting diodes LED1 to LED3 can be changed depending on the values from Vdata1 to Vdata3. The electric current can be supplied continuously through Vdd and, therefore, the light can be emitted continuously.
[0561] [0561] Transistors Tr1, Tr2 and capacitor can be formed within the supporting substrate 2510. For example, thin film transistors formed on a silicon substrate can be used to activate the active matrix.
[0562] [0562] Here, the light emitting diodes LED1 to LED3 can correspond to the first to third batteries of LEDs 2230, 2330 and 2430 stacked in one pixel, respectively. The anodes from the first to the third LED cells 2230, 2330 and 2430 are connected to transistor Tr2 and their cathodes are connected to ground.
[0563] [0563] Although FIG. 54 show the circuit for activating the active matrix according to an exemplary mode, other types of circuits can be used in several ways. In addition, although the anodes of the light-emitting diodes LED1 to LED3 are described as being connected to different transistors Tr2 and their cathodes are described as being connected to ground, the anodes of the light-emitting diodes can be connected to the Vdd and their cathodes can be connected to different transistors in some exemplary modalities.
[0564] [0564] FIG. 55 is a schematic plan view of a display device according to another exemplary embodiment. In the following, the following description will be given with reference to a pixel among a plurality of pixels arranged on the support substrate 2511.
[0565] [0565] Referring to FIG. 55, the pixel according to an exemplary embodiment is substantially similar to the pixel described with reference to FIG. 49 through FIG. 52, except that the supporting substrate 2511 is a thin film transistor panel including transistors and capacitors and the reflective electrode 2250 is arranged in a lower region of the first LED stack
[0566] [0566] The cathode of the third LED stack 2430 is connected to the support substrate 2511 through the connection portion 2711a. For example, as shown in FIG. 54, the cathode of the third LED stack 2430 can be connected to the ground via the electrical connection to the supporting substrate 2511. The cathodes of the second LED stack 2330 and the first LED stack 2230 can also be connected to the ground via electrical connection. support substrate 2511 through connection portions 2731a and 2751a.
[0567] [0567] The reflective electrode is connected to the transistors Tr2 (see FIG. 54) inside the support substrate 2511. The third transparent electrode p and the second transparent electrode p are also connected to the transistors Tr2 (see FIG. 54) inside the support substrate 2511 through connection portions 2711b and 2731b.
[0568] [0568] In this way, the first to the third LED batteries are connected to each other, thus forming a circuit for activating the active matrix, as shown in FIG. 54.
[0569] [0569] Although FIG. 55 show a pixel having an electrical connection for activating the active matrix according to an exemplary mode, the inventive concepts are not limited to this and the circuit for the display device can be modified in several circuits for activating the active matrix in several ways .
[0570] [0570] In addition, the reflective electrode 2250, the second transparent electrode p 2350 and the third transparent electrode p 2450 of FIG. 46 are described as forming ohmic contact with the p-type semiconductor layer of each of the first 2230 LED batteries, the second 2330 LED battery and the third 2430 LED battery, and the 2290 ohmic electrode is described as forming ohmic contact with the type n semiconductor layer of the first 2230 LED stack, the type n semiconductor layer of each of the second 2330 LED stack and the third 2430 LED stack is not provided with a separate ohmic contact layer. Although there is less difficulty in propagating the current, even without the formation of a separate ohmic contact layer in the n-type semiconductor layer when the pixels are small in size of 200 µm or less, however, a transparent electrode layer can be arranged in the type n semiconductor layer of each of the LED cells to guarantee the current propagation according to some exemplary modalities.
[0571] [0571] Furthermore, although FIG. 46 show the coupling of the first to the third stack of LEDs 2230, 2330 and 2430 to each other by means of connection layers, the inventive concepts are not limited to this and the first to the third stack of LEDs 2230, 2330 and 2430 can be connected to another in several sequences and using several structures.
[0572] [0572] According to exemplary modalities, since it is possible to form a plurality of pixels at the wafer level using the stack of light emitting diodes 2000 for a display, the need for individual assembly of light emitting diodes can be avoided. In addition, the stack of light-emitting diodes according to exemplary modalities has the structure in which the first to the third batteries of LEDs 2230, 2330 and 2430 are stacked in the vertical direction and, therefore, an area for sub-pixels can be protected in a limited pixel area. In addition, the battery of light emitting diodes according to the exemplary modalities allows the light generated from the first 2230 LED battery, the second 2330 LED battery and the third 2430 LED battery to be emitted out of it, reducing thus the loss of light.
[0573] [0573] FIG. 56 is a schematic plan view of a display device according to an exemplary embodiment, and FIG. 57 is a schematic cross-sectional view of a LED pixel for a display in accordance with an exemplary embodiment.
[0574] [0574] Referring to FIG. 56 and FIG. 57, the display device includes a circuit board 3510 and a plurality of pixels 3000. Each of the pixels 3000 includes a substrate 3210 and first to the third subpixels R, G and B arranged on the substrate
[0575] [0575] The 3510 circuit board may include a passive circuit or an active circuit. The passive circuit can include, for example, data lines and scan lines. The active circuit can include, for example, a transistor and a capacitor. The 3510 circuit board may have a circuit on a surface or on it. Circuit board 3510 may include, for example, a glass substrate, a sapphire substrate, a Si substrate or a Ge substrate.
[0576] [0576] Substrate 3210 supports the first to third subpixels R, G and B. Substrate 3210 is continuous across the plurality of 3000 pixels and electrically connects subpixels R, G and B to circuit board 3510. For example, substrate 3210 can be a GaAs substrate.
[0577] [0577] The first subpixel R includes a first 3230 LED battery, the second subpixel G includes a second 3330 LED battery and the third subpixel B includes a third LED battery
[0578] [0578] The first 3230 LED battery, the second LED battery
[0579] [0579] The R light generated from the first 3230 LED battery can be emitted through a region not covered by the second 3330 LED battery and the G light generated from the second 3330 LED battery can be emitted through a region not covered by the third 3430 LED battery. More particularly, the light generated from the first 3230 LED battery can be emitted to the outside without going through the second 3330 LED battery and the third 3430 LED battery, and the light generated at from the second 3330 LED battery it can be emitted to the outside without going through the third 3430 LED battery.
[0580] [0580] The region of the first 3230 LED battery through which R light is emitted, the region of the second 3330 LED battery through which G light is emitted, and the region of the third 3340 LED battery can have different areas and the intensity of the light emitted by each of the 3230, 3330 and 3430 LED cells can be adjusted by adjusting their areas.
[0581] [0581] However, inventive concepts are not limited to these. Alternatively, the light generated from the first 3230 LED battery can be emitted to the outside after passing through the second 3330 LED battery or after passing through the second 3330 LED battery and the third 3430 LED battery and the light generated from from the second 3330 LED battery it can be emitted to the outside after passing through the third 3430 LED battery.
[0582] [0582] Each of the first 3230 LED battery, the second 3330 LED battery and the third 3430 LED battery can include a first conductivity type semiconductor layer (for example, type n), a second type semiconductor layer conductivity (for example, type p) and an active layer interposed between them. The active layer can have a multi-quantum well structure. The first to the third stack of 3230, 3330 and 3430 LEDs can include different active layers to emit light with different wavelengths. For example, the first 3230 LED battery can be an inorganic light emitting diode configured to emit red light, the second 3330 LED battery can be an inorganic light emitting diode configured to emit green light and the third 3430 LED battery can be be an inorganic light emitting diode configured to emit blue light. For this purpose, the first 3230 LED stack can include an AlGaInP based well layer, the second 3330 LED stack can include an AlGaInP or AlGaInN based well layer and the third 3430 LED stack can include a well layer based on AlGaInN. However, inventive concepts are not limited to these. The wavelengths of light generated from the first 3230 LED battery, the second 3330 LED battery and the third 3430 LED battery can be varied. For example, the first 3230 LED battery, the second 3330 LED battery and the third 3430 LED battery can emit green light, red light and blue light, respectively, or they can emit green light, blue light and red light, respectively.
[0583] [0583] In addition, a distributed Bragg reflector can be interposed between the 3210 substrate and the first 3230 LED stack to prevent the loss of light generated from the first 3230 LED stack through absorption by the 3210 substrate. For example, a distributed Bragg reflector formed by alternating stacking of semiconductor layers AlAs and AlGaAs one above the other can be interposed between them.
[0584] [0584] FIG. 58 is a schematic circuit diagram of a display device according to an exemplary embodiment.
[0585] [0585] Referring to FIG. 58, the display device, according to an exemplary embodiment, can be operated in an active matrix manner. As such, the circuit board can include an active circuit.
[0586] [0586] For example, the drive circuit can include at least two transistors Tr1, Tr2 and a capacitor. When a power source is connected to the selection lines Vrow1 to Vrow3 and the voltage is applied to the data lines Vdata1 to Vdata3, the voltage is applied to the corresponding LED. In addition, the corresponding capacitors are charged according to the values from Vdata1 to Vdata3. As the activation state of transistor Tr2 can be maintained by the charged voltage of the capacitor, the voltage of the capacitor can be maintained and applied to the light-emitting cells of LED1, LED3 and LED3, even when the power supply to Vrow1 is turned off. In addition, the electric current flowing in the light emitting diodes LED1 to LED3 can be changed depending on the values from Vdata1 to Vdata3. The electric current can be supplied continuously through Vdd and, therefore, the light can be emitted continuously.
[0587] [0587] Transistors Tr1, Tr2 and capacitor can be formed within the support substrate 3510. Here, the light emitting diodes LED1 to LED3 can correspond to the first to third batteries of LEDs 3230, 3330 and 3430 stacked in one pixel, respectively. The anodes from the first to the third 3230, 3330 and 3430 LED batteries are connected to transistor Tr2 and their cathodes are connected to ground. The cathodes from the first to the third stack of LEDs 3230, 3330 and 3430, for example, can be commonly connected to ground.
[0588] [0588] Although FIG. 58 show the circuit for activating the active matrix according to an exemplary mode, other types of circuits can also be used. In addition, although the anodes of the light emitting diodes LED1 to LED3 are described as connected to the different transistors Tr2 and their cathodes are described as connected to ground, the anodes of the light emitting diodes can be commonly connected and the cathodes of the same be connected to different transistors in some exemplary modalities.
[0589] [0589] Although the active circuit for activating the active matrix is illustrated above, the inventive concepts are not limited to these, and the pixels, according to an exemplary modality, can be activated in a passive matrix manner. As such, circuit board 3510 can include data lines and scan lines arranged on it, and each of the subpixels can be connected to the data line and the scan line. In an exemplary embodiment, the anodes from the first to the third LED batteries 3230, 3330 and 3430 can be connected to different data lines and their cathodes can be commonly connected to a scan line. In other exemplary embodiments, the anodes from the first to the third LED batteries 3230, 3330 and 3430 can be connected to different scanning lines and the cathodes of them can be commonly connected to a data line.
[0590] [0590] In addition, each of the 3230, 3330 and 3430 LED batteries can be triggered by a pulse width modulation or by changing the magnitude of the electric current, thus controlling the brightness of each subpixel. In addition, the brightness can be adjusted by adjusting the areas of the first to the third 3230, 3330 and 3430 LED batteries and the areas of the 3230, 3330 and 3430 LED battery regions through which the R, G and B lights are emitted. For example, an LED battery that emits light with low visibility, for example, the first 3230 LED battery, has a larger area than the second 3330 LED battery or the third 3430 LED battery and, therefore, can emit light with greater intensity under the same current density. In addition, since the area of the second 3330 LED battery is larger than the area of the third 3430 LED battery, the second 3330 LED battery can emit light with a higher intensity under the same current density as the third battery 3430 LEDs. In this way, the light output can be adjusted based on the visibility of the light emitted from the first to the third 3230, 3330 and 3430 LED batteries, adjusting the areas of the first 3230 LED battery, the second 3330 LED battery and the third 3430 LED stack.
[0591] [0591] FIG. 59A and FIG. 59B are a top and bottom pixel view of a display device according to an exemplary embodiment, and FIG. 60A, FIG. 60B, FIG. 60C, and FIG. 60D are schematic cross-sectional views taken along lines A-A, B-B, C-C and D-D of FIG. 59A, respectively.
[0592] [0592] In the display device, the pixels are arranged on a 3510 circuit board (see FIG. 56) and each of the pixels includes a 3210 substrate and R, G and B subpixels. The 3210 substrate can be continuous along the plurality of pixels. Next, a one-pixel configuration, according to an exemplary modality, will be described.
[0593] [0593] Referring to FIG. 59A, FIG. 59B, FIG. 60A, FIG. 60B, FIG. 60C, and FIG. 60D, the pixel includes a substrate 3210, a distributed Bragg reflector 3220, an insulating layer 3250, orifice paths 3270a, 3270b, 3270c, a first stack of LED 3230, a second stack of LED 3330, a second stack of LED 3330, a third 3430 LED battery, a first ohmic electrode 1 3290a, a first ohmic electrode 2 3290b, a second ohmic electrode 1 3390, a second ohmic electrode 2 3350, a third ohmic electrode 1 3490, a third ohmic electrode 2 3490 , a third ohmic electrode 2 3450, a first connection layer 3530, a second connection layer 3550, an upper insulation layer 3610, connectors 3710, 3720, 3730, a lower insulation layer 3750 and electrode pads 3770a, 3770b, 3770c, 3770d.
[0594] [0594] Each of the R, G and B subpixels includes 3230, 3330 and 3430 LED batteries and ohmic electrodes. In addition, the anodes from the first to the third subpixels R, G and B can be electrically connected to the electrode pads 3770a, 3770b and 3770c, respectively, and their cathodes can be electrically connected to the electrode pad 3770d, thus allowing the first to the third subpixels R, G and B to be triggered independently.
[0595] [0595] Substrate 3210 supports LED stacks 3230, 3330 and 3430. Substrate 3210 can be a growth substrate on which semiconductor layers based on AlGaInP can be grown on top of it, for example, a GaAs substrate. In particular, substrate 3210 can be a semiconductor substrate exhibiting n-type conductivity.
[0596] [0596] The first 3230 LED stack includes a first semiconductor layer of conductivity type 3230a and a second semiconductor layer of conductivity type 3230b, the second stack of LED 3330 includes a first semiconductor layer of conductivity type 3330a and a second layer semiconductor of conductivity type 3330b, and the third LED stack 3430 includes a first semiconductor layer of conductivity type 3430a and a second semiconductor layer of conductivity type 3430b. An active layer can be interposed between the first semiconductor layer of conductivity type 3230a, 3330a or 3430a and the second semiconductor layer of conductivity type 3230b, 3330b or 3430b.
[0597] [0597] According to an exemplary embodiment, each of the first semiconductor layers of conductivity type 3230a, 3330a, 3430a can be a semiconductor layer of type n and each of the semiconductor layers of conductivity type 3230b, 3330b, 3430b can be a p-type semiconductor layer. A rough surface can be formed on an upper surface of each of the first semiconductor layers of conductivity type 3230a, 3330a, 3430a by texturing the surface. However, the inventive concepts are not limited to these and the first and second types of conductivity can be changed vice versa.
[0598] [0598] The first 3230 LED stack is arranged near the 3510 support substrate, the second 3330 LED stack is placed on the first 3230 LED stack and the third 3430 LED stack is placed on the second 3330 LED stack. The second pile of
[0599] [0599] The materials for the first 3230 LED battery, the second 3330 LED battery and the third 3430 LED battery are substantially the same as those described with reference to FIG. 57 and, therefore, detailed descriptions will be omitted to avoid redundancy.
[0600] [0600] The 3220 distributed Bragg reflector is interposed between the 3210 substrate and the first 3230 LED stack. The 3220 distributed Bragg reflector can include a semiconductor layer grown on the 3210 substrate. For example, the 3220 distributed Bragg reflector can be formed by alternately stacking layers of AlAs and layers of AlGaAs. The distributed Bragg reflector 3220 may include a semiconductor layer that electrically connects substrate 3210 to the first conductivity type semiconductor layer 3230a of the first 3230 LED stack.
[0601] [0601] The through-hole paths 3270a, 3270b, 3270c are formed through the substrate 3210. The through-hole paths 3270a, 3270b, 3270c can be formed to pass through the first 3230 LED stack. passage 3270a, 3270b, 3270c can be formed of conductive pastes or by plating.
[0602] [0602] The insulation layer 3250 is disposed between the through hole paths 3270a, 3270b and 3270c and an inner wall of a through hole formed through the substrate 3210 and the first stack of LED 3230 to prevent short circuit between the first 3230 LED stack and the 3210 substrate.
[0603] [0603] The first 3290a ohmic electrode forms ohmic contact with the first 3230a conductivity type semiconductor layer of the first 3230 LED stack. The first 3290a ohmic electrode can be formed, for example, by Au-Te or Au-Ge alloys .
[0604] [0604] In order to form the first ohmic electrode 3290a, the second semiconductor layer of conductivity type 3230b and the active layer can be partially removed to expose the first semiconductor layer of conductivity type 3230a. The first 3290a ohmic electrode can be disposed away from the region where the second 3330 LED battery is located. In addition, the first ohmic electrode 1 3290 can include a pad region and an extension, and connector 3710 can be connected to the pad region of the first ohmic electrode 1 3290, as shown in FIG. 59A.
[0605] [0605] The first 3220b ohmic electrode 2 forms ohmic contact with the second 3230b conductivity type semiconductor layer of the first 3230 LED stack. As shown in Fig. 59A, the first 3290b 2 ohmic electrode can be formed to partially surround the first ohmic electrode 1 3290a, in order to assist in the propagation of current. The first 3290b ohmic electrode may not include the extension. The first ohmic electrode 2 3290b can be formed from, for example, Au-Zn or Au-Be alloys. In addition, the first 3290b ohmic electrode may have a single layer or multilayer structure.
[0606] [0606] The first ohmic electrode 2 3290b can be connected to the through hole path 3270a, so that the through hole path 3270a can be electrically connected to the second semiconductor layer of conductivity type 3230b.
[0607] [0607] The second ohmic electrode 1 3390 forms ohmic contact with the first semiconductor layer of conductivity type 3330a of the second 3330 LED stack. The second ohmic electrode 1 3390 can also include a pad region and an extension. As shown in Fig. 59A, connector 3710 can electrically connect the second ohmic electrode 3390 to the first ohmic electrode 3290a. The second ohmic electrode 1 3390 can be placed in the part of the region where the third 3430 LED battery is located.
[0608] [0608] The second ohmic electrode 2 3350 forms ohmic contact with the second semiconductor layer of conductivity type 3330b of the second 3330 LED stack. The second ohmic electrode 2 3350 may include a reflective layer 3350a and a barrier layer 3350b. The reflective layer 3350a reflects the light generated from the second 3330 LED stack to improve the luminous efficacy of the second 3330 LED stack. The 3350b barrier layer can act as a connection pad, which provides the 3350a reflective layer, and is connected to connector 3720. Although the second ohmic electrode 2 3350 is described as including a metal layer in this exemplary embodiment, the inventive concepts are not limited to these. For example, the second ohmic electrode 2 3350 can be formed of a transparent conductive oxide, such as a conductive oxide semiconductor layer.
[0609] [0609] The third ohmic electrode 1 3490 forms ohmic contact with the first semiconductor layer of conductivity type 3430a from the third 3430 LED stack. The third ohmic electrode 1 3490 can also include a pad region and an extension, and the 3710 connector can connect the third ohmic electrode 1 3490 to the first ohmic electrode 1 3290a, as shown in FIG. 59A.
[0610] [0610] The third ohmic electrode 2 3450 can form ohmic contact with the second semiconductor layer of conductivity type 3430b of the third 3430 LED stack. The third ohmic electrode 2 3450 can include a reflective layer 3450a and a barrier layer 3450b. The reflective layer 3450a reflects the light generated from the third 3430 LED stack to improve the luminous efficacy of the third 3430 LED stack. The 3450b barrier layer can act as a connection pad, which provides the 3450a reflective layer, and is connected to connector 3730. Although the third ohmic 3450 electrode is described as including a metal layer, the inventive concepts are not limited to these. Alternatively, the third ohmic electrode 2 3450 can be formed of a transparent conductive oxide, such as a conductive oxide semiconductor layer.
[0611] [0611] The first ohmic electrode 2 3290b, the second ohmic electrode 2 3350 and the third ohmic electrode 2 3450 can form ohmic contact with the p-type semiconductor layers of the corresponding LED cells to assist in current propagation and the first ohmic electrode 1 3290a, the second ohmic electrode 1 3390 and the third ohmic electrode 1 3490 can form ohmic contact with the n-type semiconductor layers of the corresponding LED cells to aid in current propagation.
[0612] [0612] The first 3530 connection layer couples the second 3330 LED battery to the first 3230 LED battery. As shown in the drawings, the second ohmic electrode 2 3350 can join with the first 3530 connection layer. The first connection layer 3530 can be a light transmitting layer or an opaque layer. The first 3530 bonding layer can be formed from an organic material or an 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. The organic material layer can be bonded under high vacuum, and the inorganic material layer can be bonded under high vacuum after flattening the surface of the first bonding layer by, for example, mechanical chemical polishing, followed by adjusting the surface energy through plasma treatment. The first 3530 bonding layer can be formed by spin-on-glass or it can be a metal bonding layer formed by AuSn or the like. For the metal bonding layer, an insulation layer can be arranged on the first 3230 LED stack to protect the electrical insulation between the first 3230 LED stack and the metal bonding layer. In addition, a reflective layer can be further arranged between the first 3530 connection layer and the first 3230 LED battery to prevent the light generated from the first 3230 LED battery from entering the second 3330 LED battery.
[0613] [0613] The second 3550 connection layer couples the second 3330 LED battery to the third 3430 LED battery. The second 3550 connection layer can be interposed between the second 3330 LED battery and the third 3450 ohmic electrode to connect the second 3330 LED stack to the third ohmic 3450 electrode. The second 3550 bonding layer can be formed of substantially the same bonding material as the first 3530 bonding layer. In addition, an insulating layer and / or a reflective layer can also be arranged between the second 3330 LED battery and the second 3550 connection layer.
[0614] [0614] When the first 3530 bonding layer and the 3550 second bonding layer are formed of a light transmitting material, and the second ohmic electrode 2 3350 and the third ohmic electrode 2 3450 are formed of a transparent oxide material, some light fractions generated from the first 3230 LED battery can be emitted through the second 3330 LED battery after passing through the first 3530 connection layer and the second 3350 ohmic electrode and can also be emitted through the third 3430 LED battery after passing through the second 3550 connection layer and the third ohmic electrode 2 3450. In addition, some light fractions generated from the second 3330 LED battery can be emitted through the third 3430 LED battery after passing through the second connection layer 3550 and the third ohmic electrode 2 3450.
[0615] [0615] In this case, the light generated from the first 3230 LED battery must be prevented from being absorbed by the second 3330 LED battery while passing through the second 3330 LED battery. As such, the light generated from the first 3230 LED battery 3230 LED can have a smaller bandwidth than the second 3330 LED stack and therefore can have a longer wavelength than the light generated from the second 3330 LED stack.
[0616] [0616] Furthermore, to prevent the light generated from the second 3330 LED battery from being absorbed by the third 3430 LED battery while passing through the third 3430 LED battery, the light generated from the second 3330 LED battery may have a longer wavelength than the light generated from the third 3430 LED stack.
[0617] [0617] When the first 3530 link layer and the second 3550 link layer are formed of opaque materials, the reflective layers are interposed between the first 3230 LED stack and the first 3530 link layer and between the second 3330 LED stack and the second link layer 3550, respectively, to reflect light having been generated from the first 3230 LED stack and entering the first link 3530 and light having been generated from the second 3330 LED stack and entering the second layer connection 3550. The reflected light can be emitted through the first 3230 LED battery and the second 3330 LED battery.
[0618] [0618] The top insulating layer 3610 can cover the first to the third 3230, 3330 and 3430 LED batteries. In particular, the top insulating layer 3610 can cover the side surfaces of the second 3330 LED stack and the third LED stack. 3430, and can also cover the side surface of the first 3230 LED battery.
[0619] [0619] The top insulation layer 3610 has openings that expose the first to third through-hole paths 3270a, 3270b, 3270c and openings that expose the first semiconductor layer of conductivity type 3330a from the second 3330 LED stack, the first layer conductivity type semiconductor 3430a from the third 3430 LED stack, the second ohmic electrode 3350 and the third ohmic electrode 3450.
[0620] [0620] The upper insulation layer 3610 can be formed from any insulation material, for example, silicon oxide or silicon nitride, without being limited to these.
[0621] [0621] Connector 3710 electrically connects the first ohmic electrode 1 3290a, the second ohmic electrode 1 3390 and the third ohmic electrode 1 3490 to each other. The connector 3710 is formed in the upper insulation layer 3610 and is isolated from the second semiconductor layer of conductivity type 3430b of the third stack of LED 3430, the second semiconductor layer of conductivity type 3330b from the second stack of LED 3330 and the second semiconductor layer conductivity type 3230b from the first 3230 LED battery.
[0622] [0622] Connector 3710 can be formed of substantially the same material as the second ohmic electrode 1 3390 and the third ohmic electrode 1 3490 and therefore can be formed together with the second ohmic electrode 1 3390 and the third ohmic electrode 1 3490 Alternatively, connector 3710 can be formed from a conductive material other than the second ohmic electrode 1 3390 or the third ohmic electrode 1 3490 and therefore can be formed separately in a process different from the second ohmic electrode 1 3390 and / or the third electrode ohmic 1 3490.
[0623] [0623] Connector 3720 can electrically connect the second ohmic electrode 1 3350, for example, the barrier layer 3350b, to the second through hole 3270b. The 3730 connector electrically connects the third ohmic electrode 1, for example, the barrier layer 3450b, to the third through-hole path 3270c. The 3720 connector can be electrically isolated from the first 3230 LED stack by the top insulation layer
[0624] [0624] Connectors 3720, 3730 can be formed together by the same process. Connector 3720, 3730 can also be formed in conjunction with connector 3710. In addition, connectors 3720, 3730 can be formed of substantially the same material as the second ohmic electrode 1 3390 and the third ohmic electrode 1 3490, and can be formed together with them. Alternatively, connectors 3720, 3730 can be formed from a conductive material other than the second ohmic electrode 1 3390 or the third ohmic electrode 1 3490 and therefore can be formed separately by a process different from the second ohmic electrode 1 3390 and / or the third ohmic electrode 1
[0625] [0625] The bottom insulating layer 3750 covers a lower surface of the substrate 3210. The lower insulating layer 3750 can include openings that expose the first to third through-hole paths 3270a, 3270b, 3270c on the bottom side of the substrate 3210 and also may include openings that expose the bottom surface of the 3210 substrate.
[0626] [0626] The electrode pads 3770a, 3770b, 3770c and 3770d are arranged on the bottom surface of the substrate 3210. The electrode pads 3770a, 3770b and 3770c are connected to the through hole paths 3270a, 3270b and 3270c through the layer openings insulation 3750 and the 3770d electrode pad is connected to the 3210 substrate.
[0627] [0627] The electrode pads 3770a, 3770b and 3770c are supplied to each pixel to be electrically connected to the first to third LED batteries 3230, 3330 and 3430 of each pixel, respectively. Although the 3770d electrode pad can also be provided for each pixel, the 3210 substrate is continuously arranged over a plurality of pixels, which can avoid the need to provide the 3770d electrode pad for each pixel.
[0628] [0628] The electrode pads 3770a, 3770b, 3770c, 3770d are connected to the circuit board 3510, thus providing a display device.
[0629] [0629] In the following, a method of manufacturing the display device according to an exemplary embodiment will be described.
[0630] [0630] FIG. 61A to FIG. 68B are schematic plan views and cross-sectional views illustrating a method of manufacturing the display device according to an exemplary embodiment. Each of the cross-sectional views is taken along a line shown in each corresponding flat view.
[0631] [0631] Referring to FIG. 61A and 61B, a first 3230 LED stack is grown on a 3210 substrate. The 3210 substrate can be, for example, a GaAs substrate. The first 3230 LED stack consists of semiconductor layers based on AlGaInP and includes a first semiconductor layer of conductivity type 3230a, an active layer and a second semiconductor layer of conductivity type 3230b. A 3220 distributed Bragg reflector can be formed prior to the growth of the first 3230 LED stack. The 3220 distributed Bragg reflector can have a stack structure formed by repeatedly stacking, for example, layers of AlAs / AlGaAs.
[0632] [0632] Then, grooves are formed in the first 3230 LED stack and in the 3210 substrate through photolithography and engraving. The grooves can be formed to pass through the substrate 3210 or can be formed at a predetermined depth in the substrate 3210, as shown in FIG. 61B.
[0633] [0633] Then, an insulating layer 3250 is formed to cover the side walls of the grooves and the through hole paths 3270a, 3270b, 3270c are formed to fill the grooves. Through-hole paths 3270a, 3270b and 3270c can be formed, for example, by forming an insulating layer to cover the side walls of the grooves,
[0634] [0634] Referring to FIG. 62A and FIG. 62B, a second 3330 LED battery and a second 3350 ohmic electrode can be coupled to the first 3230 LED battery via the first connection layer
[0635] [0635] The second 3330 LED stack is grown on a second substrate and the second 3350 ohmic electrode is formed on the second 3330 LED stack. The second 3330 LED stack is made up of semiconductor layers based on AlGaInP or the base of AlGaInN and can include a first semiconductor layer of conductivity type 3330a, an active layer and a second semiconductor layer of conductivity type 3330b. The second substrate can be a substrate on which the AlGaInP-based semiconductor layers can be grown on it, for example, a GaAs substrate or a substrate on which the AlGaInN-based semiconductor layers can be grown on it, for example, a sapphire. The composition ratio of Al, Ga and In for the second 3330 LED battery can be determined so that the second 3330 LED battery can emit green light. The second ohmic electrode 2 3350 forms ohmic contact with the second semiconductor layer of conductivity type 3330b, for example, a semiconductor layer of type p. The second ohmic electrode 2 3350 may include a reflective layer 3350a, which reflects the light generated from the second 3330 LED stack and a barrier layer 3350b.
[0636] [0636] The second ohmic electrode 2 3350 is arranged to face the first 3230 LED battery and is coupled to the first 3230 LED battery by the first 3530 connection layer. After that, the second substrate is removed from the second 3330 LED battery to exposing the first semiconductor layer of conductivity type 3330a by chemical engraving or laser lifting. A rough surface can be formed on the first conductivity type semiconductor layer 3330a exposed by surface texturing.
[0637] [0637] According to an exemplary embodiment, an insulating layer and a reflecting layer can be further formed on the first 3230 LED stack before the first 3530 connection layer is formed.
[0638] [0638] Referring to FIG. 63A and FIG. 63B, a third 3430 LED battery and a third 3450 ohmic electrode 2 can be coupled to the second 3330 LED battery via the second 3550 connection layer.
[0639] [0639] The third 3430 LED stack is grown on a third substrate and the third 3450 ohmic electrode is formed on the third 3430 LED stack. The third 3430 LED stack is made up of semiconductor layers based on AlGaInN and can include a first semiconductor layer of conductivity type 3430a, an active layer and a second semiconductor layer of conductivity type 3430b. The third substrate is a substrate on which the GaN-based semiconductor layers can be grown on it and is different from the first 3210 substrate. The composition ratio of AlGaInN to the third 3430 LED stack can be determined so that the third stack of LED 3430 can emit blue light. The third ohmic electrode 2 3450 forms ohmic contact with the second semiconductor layer of conductivity type 3430b, for example, a semiconductor layer of type p. The third ohmic electrode 2 3450 may include a reflective layer 3450a, which reflects the light generated from the third 3430 LED stack and a barrier layer 3450b.
[0640] [0640] The third ohmic electrode 2 3450 is arranged to face the second battery of LED 3330 and is coupled to the second battery of LED 3330 by the second layer of connection 3550. After that, the third substrate is removed from the third battery of LED 3430 to expose the first semiconductor layer of conductivity type 3430a by chemical engraving or laser lifting. A rough surface can be formed in the first semiconductor layer 3430a of the conductivity type exposed by surface texturing.
[0641] [0641] According to an exemplary embodiment, an insulating layer and a reflecting layer can be further formed on the second 3330 LED stack before the second 3550 connection layer is formed.
[0642] [0642] Referring to FIG. 64A and FIG. 64B, in each of the pixel regions, the third 3430 LED stack is standardized to remove the third 3430 LED stack other than the third subpixel B. In a region of the third subpixel B, an indentation is formed in the third stack of LEDs. LED 3430 to expose the barrier layer 3450b through indentation.
[0643] [0643] Then, in regions other than the third subpixel B, the third ohmic electrode 2 3450 and the second connection layer 3550 are removed to expose the second LED battery
[0644] [0644] In each pixel region, the second 3330 LED stack is standardized to remove the second 3330 LED stack in regions other than the second G sub pixel. In the second G sub pixel region, the second 3330 LED stack overlaps partially to the third 3430 LED battery.
[0645] [0645] When standardizing the second 3330 LED battery, the second ohmic electrode 2 3350 is exposed. The second 3330 LED stack can include an indentation, and the second ohmic electrode 3350, for example, the barrier layer 3350b, can be exposed through the indentation.
[0646] [0646] Subsequently, the second ohmic electrode 2 3350 and the first layer of connection 3530 are removed to expose the first stack of LED 3230. As such, the second ohmic electrode 2 3350 is disposed close to the region of the second subpixel G. On the other hand In addition, the first to third through-hole paths 3270a, 3270b and 3270c are also exposed together with the first 3230 LED battery.
[0647] [0647] In each pixel region, the first semiconductor layer of conductivity type 3230a is exposed by standardizing the second semiconductor layer of conductivity type 3230b of the first stack of LED 3230. As shown in Fig. 64A, the first semiconductor layer of type conductivity 3230a can be exposed in an elongated form, without being limited to it.
[0648] [0648] In addition, the pixel regions are divided from one another, standardizing the first 3230 LED stack. As such, a region of the first R subpixel is defined. Here, the distributed Bragg reflector 3220 can also be divided. Alternatively, the distributed Bragg reflector 3220 can be arranged continuously over the plurality of pixels, instead of being divided. In addition, the first semiconductor layer of conductivity type 3230a can also be arranged continuously over the plurality of pixels.
[0649] [0649] Referring to FIG. 65A and FIG. 65B, a first ohmic electrode 1 3290a and a first ohmic electrode 2 3290b are formed in the first 3230 LED stack. The first ohmic electrode 1 3290a can be formed, for example, by Au-Te or Au-Ge alloys in the first layer conductivity type 3230a semiconductor exposed. The first ohmic electrode 2 3290b can be formed, for example, by Au-Be or Au-Zn alloys in the second semiconductor layer of conductivity type 3230b. The first ohmic electrode 2 3290b can be formed before the first ohmic electrode 1 3290a, or vice versa. The first ohmic electrode 2 3290b can be connected to the first through-hole path 3270a. On the other hand, the first ohmic electrode 1 3290a may include a pad region and an extension, which may extend from the pad region towards the first through-hole path 3270a.
[0650] [0650] For current propagation, the first ohmic electrode 2 3290b can be arranged to at least partially surround the first ohmic electrode 1 3290a. Although each of the first ohmic electrode 1 3290a and the first ohmic electrode 2 3290b are being illustrated as having an elongated shape in FIG. 65A, inventive concepts are not limited to these. Alternatively, each of the first ohmic electrodes 1 3290a and first ohmic electrodes 2 3290b may have a circular shape, for example.
[0651] [0651] Referring to FIG. 66A and FIG. 66B, a top insulation layer 3610 is formed to cover the first to third LED batteries 3230, 3330, 3430. The top insulation layer 3610 can cover the first ohmic electrode 1 3290a and the first ohmic electrode 2 3290b. The top insulation layer 3610 can also cover side surfaces of the first to third 3230, 3330 and 3430 LED batteries and a side surface of the distributed Bragg reflector 3220.
[0652] [0652] The upper insulating layer 3610 may have an opening 3610a that exposes the first ohmic electrode 1 3290a, openings 3610b, 3610c that expose barrier layers 3350b, 3450b, openings 3610d, 3610e that expose the second and third orifice paths bypass 3270b, 3270c and openings 3610f, 3610g, which expose the first semiconductor layers of conductivity type 3330a, 3430a of the second 3330 LED battery and the third 3430 LED battery.
[0653] [0653] Referring to FIG. 67A and FIG. 67B, a second ohmic electrode 1 3390, a third ohmic electrode 1 3490 and connectors 3710, 3720, 3730 are formed. The second ohmic electrode 1 3390 is formed at the opening 3610f to form ohmic contact with the first semiconductor layer of conductivity type 3330a, and the third ohmic electrode 1 3490 is formed at the opening 3610g to form ohmic contact with the first semiconductor layer of conductivity type. conductivity 3430a.
[0654] [0654] Connector 3710 electrically connects the second ohmic electrode 1 3390 and the third ohmic electrode 1 3490 to the first ohmic electrode 1 3290a. Connector 3710 can be connected, for example, to the first ohmic electrode 1 3290a exposed in opening 3610a. The connector 3710 is formed in the upper insulating layer 3610 to be isolated from the second semiconductor layers of conductivity type 3230b, 3330b and 3430b.
[0655] [0655] Connector 3720 electrically connects the second ohmic electrode 2 3350 to the second through-hole 3270b and connector 3730 electrically connects the third ohmic electrode 3450 to the third through-hole 3270c. The 3720, 3730 connectors are arranged in the upper insulation layer 3610 to avoid short-circuiting the first to third 3230, 3330 and 3430 LED batteries.
[0656] [0656] The second ohmic electrode 1 3390, the third ohmic electrode 1 3490 and connectors 3710, 3720, 3730 can be formed from substantially the same material by the same process. However, inventive concepts are not limited to these. Alternatively, the second ohmic electrode 1 3390, the third ohmic electrode 1 3490 and connectors 3710, 3720, 3730 can be formed of different materials by different processes.
[0657] [0657] Then, with reference to FIG. 68A and FIG. 68B, a lower insulating layer 3750 is formed on a lower surface of the substrate 3210. The lower insulating layer 3750 has openings that expose the first to third through-hole paths 3270a, 3270b, 3270c and may also have openings that expose the bottom surface of substrate 3210.
[0658] [0658] The electrode pads 3770a, 3770b, 3770c, 3770d are formed in the bottom insulating layer 3750. The electrode pads 3770a, 3770b, 3770c are connected to the first to third through-hole 3270a, 3270b, 3270c, respectively , and the 3770d electrode pad is connected to the 3210 substrate.
[0659] [0659] Consequently, the 3770a electrode pad is electrically connected to the second 3230b conductivity type semiconductor layer of the first 3230 LED stack via the first through-hole path 3270a, the 3770b electrode pad is electrically connected to the second layer conductivity type 3330b semiconductor from the second 3330 LED stack through the second through-hole path 3270b and electrode pad 3770c is electrically connected to the second conductivity type 3430b semiconductor layer from the third 3430 LED stack via the third way through hole 3270c. The first semiconductor layers of conductivity type 3230a, 3330a, 3430a from the first to the third LED stack 3230, 3330, 3430 are commonly electrically connected to the 3770d electrode pad.
[0660] [0660] In this way, a display device, according to an exemplary embodiment, can be formed by connecting the electrode pads 3770a, 3770b, 3770c, 3770d of substrate 3210 to the circuit board 3510 shown in FIG. 56. As described above, circuit board 3510 can include an active circuit or a passive circuit, whereby the display device can be actuated in an active or passive matrix manner.
[0661] [0661] FIG. 69 is a cross-sectional view of a pixel of LED light for a display according to an exemplary embodiment.
[0662] [0662] Referring to FIG. 69, the LED pixel 3001 of the display device, according to an exemplary embodiment, is generally similar to the LED pixel 3000 of the display device of FIG. 57, except that the second 3330 LED battery covers most of the first 3230 LED battery and the third 3430 LED battery covers most of the second 3330 LED battery. In this way, the light generated from the first R subpixel it is emitted to the outside after passing substantially through the second 3330 LED battery and the third 3430 LED battery, and the light generated from the second 3330 LED battery is emitted to the outside after substantially passing through the third 3430 LED battery.
[0663] [0663] The first stack of 3230 LEDs can include an active layer with a bandwidth narrower than the second stack of LED 3330 and the third stack of LED 3430 to emit light with a wavelength longer than the second stack of LED 3330 and the third battery of LED 3430 and the second battery of LED 3330 can include an active layer with a bandwidth narrower than the third battery of LED 3430 to emit light with a wavelength longer than the third battery 3430 LED.
[0664] [0664] FIG. 70 is an enlarged one-pixel view of a display device according to an exemplary embodiment, and FIG. 71A and FIG. 71B are seen in cross section taken along lines G-G and H-H of FIG. 70, respectively.
[0665] [0665] Referring to FIG. 70, FIG. 71A, and FIG. 71B, the pixel, according to an exemplary embodiment, is generally similar to the pixel of FIG. 59, FIG. 60A, FIG. 60B and FIG. 60C, except that the second 3330 LED battery covers most of the first 3230 LED battery and the third 3430 LED battery covers most of the second 3330 LED battery. The first to third through-hole 3270a, 3270b , 3270c can be arranged outside the second 3330 LED stack and the third LED stack
[0666] [0666] In addition, a portion of the first 3290a ohmic electrode and a portion of the second 3390 ohmic electrode can be arranged under the third 3430 LED battery. As such, the first 3290a ohmic electrode can be formed before the second LED battery 3330 can be coupled to the first 3230 LED battery and the second ohmic electrode 1 3390 can also be formed before the third 3430 LED battery is coupled to the second LED battery
[0667] [0667] In addition, the light generated from the first 3230 LED battery is emitted to the outside after substantially passing through the second 3330 LED battery and the third 3430 LED battery, and the light generated from the second LED battery 3330 is emitted to the outside after passing substantially through the third 3430 LED stack. Therefore, the first 3530 connection layer and the second 3550 connection layer are formed by light transmitting materials, and the second ohmic electrode 2 3350 and the third ohmic electrode 2 3450 are composed of transparent conductive layers.
[0668] [0668] On the other hand, as shown in FIGS. 71A and 71B, an indentation can be formed on the third 3430 LED stack to expose the third 3450 ohmic electrode and an indentation is formed continuously on the third 3430 LED stack and the second 3330 LED stack to expose the second 3333 ohmic electrode. The second ohmic electrode 2 3350 and the third ohmic electrode 2 3450 are electrically connected to the second via orifice 3270b and the third via via 3232c via connectors 3720, 3730, respectively.
[0669] [0669] In addition, indentation can be formed on the third 3430 LED stack to expose the second ohmic electrode 1 3390 formed on the first conductivity type 3330a semiconductor layer of the second 3330 LED stack, and the indentation can be formed continuously on the third 3430 LED battery and the second 3330 LED battery to expose the first 3290a ohmic electrode 1 formed in the first 3230a conductivity type semiconductor layer of the first 3230 LED cell. The 3710 connector can connect the first 3290a ohmic electrode and the second ohmic electrode 1 3390 to the third ohmic electrode 1
[0670] [0670] The first ohmic electrode 1 3290a and the second ohmic electrode 1 3390 are partially placed under the third 3430 LED stack, but the inventive concepts are not limited to these. For example, the portions of the first ohmic electrode 1 3290a and the second ohmic electrode 1 3390 arranged under the third LED stack 3430 can be omitted. In addition, the second ohmic electrode 1 3390 can be omitted and the connector 3710 can form ohmic contact with the first semiconductor layer of conductivity type 3330a.
[0671] [0671] According to exemplary modalities, a plurality of pixels can be formed at the wafer level through the connection of the wafer and, thus, the process of individual assembly of light emitting diodes can be avoided or substantially reduced.
[0672] [0672] Furthermore, since through-hole paths 3270a, 3270b, 3270c are formed on substrate 3210 and used as current paths, substrate 3210 may not need to be removed. Therefore, a growth substrate used for the growth of the first 3230 LED stack can be used as the 3210 substrate without being removed from the first 3230 LED stack.
[0673] [0673] 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 (20)
[1]
1. Light emitting diode (LED) stack for display, characterized by comprising: a first LED subunit having a first surface and a second surface; a second LED subunit arranged on the first surface of the first LED subunit; a third LED subunit arranged in the second LED subunit; a reflective electrode disposed on the second side of the second LED subunit and forming ohmic contact with the first LED subunit; and an ohmic electrode interposed between the first LED subunit and the second LED subunit and forming ohmic contact with the first LED subunit, where: the second LED subunit and the third LED subunit are configured to transmit light generated from the first LED subunit; and the third LED subunit is configured to transmit light generated from the second LED subunit.
[2]
2. LED stack for a display, according to claim 1, characterized in that the first, second and third LED subunits comprise the first, second and third LED batteries, respectively.
[3]
3. LED stack for a display, according to claim 1, characterized in that the LED stack comprises a micro LED with a surface area of less than about 200 µm square.
[4]
4. LED stack for a display, according to claim 1, characterized in that the reflecting electrode and the ohmic electrode have different reflection indexes from each other.
[5]
5. LED battery for a display, according to claim 2, characterized in that the first, second and third LED batteries are configured to emit red light, green light and blue light, respectively.
[6]
6. LED stack for a display, according to claim 2, further comprising: a first color filter interposed between the first LED stack and the second LED stack, and configured to transmit light generated from the first LED stack and reflect the light generated from the second LED stack; and a second color filter interposed between the second LED battery and the third LED battery, and configured to transmit the light generated from the first and second LED batteries and reflect the light generated from the third LED battery.
[7]
7. LED stack for a display, according to claim 6, characterized in that each of the first color filters and the second color filter comprises at least one among a low pass filter, a bandpass filter and a filter band interruption.
[8]
8. LED stack for a display, according to claim 7, characterized in that each of the first and second color filters comprises a distributed Bragg reflector.
[9]
9. LED stack for a display, according to claim 2, characterized by further comprising: a support substrate; a first bonding layer interposed between the support substrate and the first LED stack; a second connection layer interposed between the first LED battery and the second LED battery; and a third link layer interposed between the second LED stack and the third LED stack, wherein: the second link layer is configured to transmit light generated from the first LED stack; and the third link layer is configured to transmit light generated from the first and second LED batteries.
[10]
10. LED stack for a display, according to claim 9, characterized by: the first connection layer joining with the reflecting electrode; and the second bonding layer joins the ohmic electrode.
[11]
11. LED stack for a display, according to claim 10, characterized by further comprising: a second transparent electrode forming ohmic contact with a p-type semiconductor layer of the second LED stack; and a third transparent p electrode forming ohmic contact with a p-type semiconductor layer of the third LED stack.
[12]
12. LED stack for a display according to claim 11, characterized in that the second connection layer joins a type n semiconductor layer of the first LED stack and the third connection layer joins a type n semiconductor layer of the second one LED stack.
[13]
13. LED stack for a display, according to claim 12, further comprising: a first color filter interposed between the first LED stack and the second LED stack and configured to transmit light generated from the first stack LED and reflect the light generated from the second LED stack; and a second color filter interposed between the second LED battery and the third LED battery, and configured to transmit the light generated from the first and second LED batteries and reflect the light generated from the third LED battery, wherein the first color filter is disposed on the second connection layer and the second color filter is disposed on the third connection layer.
[14]
14. Display device comprising a plurality of pixels arranged on a support substrate, characterized in that at least some of the pixels comprise the LED stack of claim 2.
[15]
Display device according to claim 14, characterized in that: each of the first, second and third LED cells comprises a p-type semiconductor layer and a n-type semiconductor layer;
each of the p-type semiconductor layers of the first, second and third LED cells will be electrically connected to a common line; and each of the n-type semiconductor layers of the first, second and third LED cells is electrically connected to different lines from one another.
[16]
16. Display device according to claim 15, characterized in that the common line comprises a data line and the different lines comprise scan lines.
[17]
17. Display device according to claim 14, further comprising: a lower insulation layer covering the side surfaces of the first, second and third LED cells, the lower insulation layer comprising openings that expose the ohmic electrode, the reflective electrode, the second LED battery and the third LED battery.
[18]
18. Display device according to claim 17, characterized in that the lower insulation layer comprises a distributed Bragg reflector configured to reflect red, green and blue light.
[19]
19. Display device according to claim 15, characterized in that the reflecting electrode comprises the common line and is continuously arranged over the plurality of pixels.
[20]
20. Display device according to claim 14, characterized in that the reflecting electrode is disposed within each pixel region.

类似技术:

---

公开号 | 公开日 | 专利标题

---

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

---

BR112020010688A2|2020-11-10|led unit for display and display device having the same

---

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

---

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

---

BR112020010695A2|2020-11-10|led unit for display and display device having the same

---

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

---

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

---

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

---

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

---

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

---

JP2019087746A|2019-06-06|High resolution display device

---

US20220005971A1|2022-01-06|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

---

EP3923328A1|2021-12-15|

---

CN110828435A|2020-02-21|

---

EP3923328A4|2021-12-15|

---

EP3718139A4|2021-10-13|

---

EP3913668A4|2021-11-24|

---

EP3923327A1|2021-12-15|

---

EP3913669A1|2021-11-24|

---

EP3913668A1|2021-11-24|

---

EP3913669A4|2021-11-24|

---

US20200328250A1|2020-10-15|

---

US20190165038A1|2019-05-30|

---

EP3913670A1|2021-11-24|

---

US10892297B2|2021-01-12|

---

KR20200085770A|2020-07-15|

---

CN110192276A|2019-08-30|

---

CN111223845A|2020-06-02|

---

CN110690248A|2020-01-14|

---

US20210351230A1|2021-11-11|

---

EP3913670A4|2021-11-24|

---

WO2019103579A1|2019-05-31|

---

CN110729283A|2020-01-24|

---

EP3923327A4|2021-12-15|

---

US20210335886A1|2021-10-28|

---

EP3718139A1|2020-10-07|

---

US20210335887A1|2021-10-28|

---

JP2021504752A|2021-02-15|

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|

---

FR2726126A1|1994-10-24|1996-04-26|Mitsubishi Electric Corp|LED device mfr. by thermally bonding LEDs|

---

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|

---

TW522534B|2001-09-11|2003-03-01|Hsiu-Hen Chang|Light source of full color LED using die bonding and packaging technology|

---

CN100358163C|2002-08-01|2007-12-26|日亚化学工业株式会社|Semiconductor light-emitting device, method for manufacturing same and light-emitting apparatus using same|

---

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

---

JP2005072323A|2003-08-26|2005-03-17|Oki Data Corp|Semiconductor device|

---

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|

---

US7528810B2|2004-05-25|2009-05-05|Victor Company Of Japan, Limited|Display with multiple emission layers|

---

US20070170444A1|2004-07-07|2007-07-26|Cao Group, Inc.|Integrated LED Chip to Emit Multiple Colors and Method of Manufacturing the Same|

---

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|

---

JP5193048B2|2005-09-30|2013-05-08|ソウルオプトデバイスカンパニーリミテッド|Light emitting device having vertically stacked light emitting diodes|

---

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|

---

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

---

US20080308819A1|2007-06-15|2008-12-18|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|

---

US8022421B2|2007-11-06|2011-09-20|Industrial Technology Institute|Light emitting module having LED pixels and method of forming the same|

---

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|

---

US8163581B1|2010-10-13|2012-04-24|Monolith IC 3D|Semiconductor and optoelectronic 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|

---

FR2964498A1|2011-03-21|2012-03-09|Soitec Silicon On Insulator|Semiconductor light-emitting plate for use in e.g. computer screen, has first and second light-emitting layers that are connected together by molecular bonding without requiring any adhesive|

---

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|

---

TWI686971B|2013-08-09|2020-03-01|日商半導體能源研究所股份有限公司|Light-emitting element, display module, lighting module, light-emitting device, display device, electronic device, and lighting device|

---

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|

---

US9831387B2|2014-06-14|2017-11-28|Hiphoton Co., Ltd.|Light engine array|

---

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|

---

JP6413460B2|2014-08-08|2018-10-31|日亜化学工業株式会社|LIGHT EMITTING DEVICE AND LIGHT EMITTING DEVICE MANUFACTURING METHOD|

---

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|

---

JP6637674B2|2015-04-30|2020-01-29|信越化学工業株式会社|Printed wiring board, method for manufacturing printed wiring board, and semiconductor device|

---

CN104952995B|2015-05-05|2017-08-25|湘能华磊光电股份有限公司|A kind of inverted structure of III light emitting semiconductor device|

---

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|

---

TWI577042B|2015-07-15|2017-04-01|南臺科技大學|Light emitting diode chip and data trasmission and recepition apparatus|

---

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|

---

US10032757B2|2015-09-04|2018-07-24|Hong Kong Beida Jade Bird Display Limited|Projection display system|

---

US10304811B2|2015-09-04|2019-05-28|Hong Kong Beida Jade Bird Display Limited|Light-emitting diode display panel with micro lens array|

---

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

---

KR20170042426A|2015-10-08|2017-04-19|삼성디스플레이 주식회사|Organic light emitting device, organic light emitting display device having the same and fabricating method of the same|

---

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

---

KR20170082187A|2016-01-05|2017-07-14|삼성전자주식회사|White light emitting device and display apparatus|

---

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|

---

EP3586368A4|2017-02-24|2020-12-09|Massachusetts Institute of Technology |Methods and apparatus for vertically stacked multicolor light-emitting diode display|

---

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|

---

US20200212262A1|2018-12-31|2020-07-02|Seoul Viosys Co., Ltd.|Light emitting device package and display device having the same|US10622342B2|2017-11-08|2020-04-14|Taiwan Semiconductor Manufacturing Company Ltd.|Stacked LED structure and associated manufacturing method|

---

WO2020257391A1|2019-06-19|2020-12-24|Hong Kong Beida Jade Bird Display Limited|Systems and methods for coaxial multi-color led|

---

KR102170243B1|2019-06-24|2020-10-26|주식회사 썬다이오드코리아|Multijunction LED with Eutectic Metal-Alloy Bonding and Method of manufacturing the same|

---

US11049992B2|2019-07-11|2021-06-29|Pix Art Imaging Inc.|Dual wavelength light emitting device, dual wavelength light transceiving device and display|

---

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

---

US20210098526A1|2019-09-27|2021-04-01|Seoul Viosys Co., Ltd.|Light emitting device for display and display apparatus having the same|

---

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

---

CN110649060A|2019-11-01|2020-01-03|京东方科技集团股份有限公司|Micro light emitting diode chip, manufacturing method thereof and display panel manufacturing method|

---

US20220005792A1|2020-01-22|2022-01-06|Seoul Viosys Co., Ltd.|Light emitting device and display apparatus having the same|

---

CN113556882A|2020-04-23|2021-10-26|鹏鼎控股股份有限公司|Manufacturing method of transparent circuit board and transparent circuit board|

---

CN112291917B|2020-10-15|2021-05-14|深圳市顺华智显技术有限公司|Flexible circuit board and manufacturing method thereof|

---

CN112736169A|2021-03-30|2021-04-30|北京芯海视界三维科技有限公司|Light emitting device and display apparatus|

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

---

US201762590810P| true| 2017-11-27|2017-11-27|

---

US201762590854P| true| 2017-11-27|2017-11-27|

---

US201762590870P| true| 2017-11-27|2017-11-27|

---

US62/590,870|2017-11-27|

---

US62/590,854|2017-11-27|

---

US62/590,810|2017-11-27|

---

US201862621503P| true| 2018-01-24|2018-01-24|

---

US62/621,503|2018-01-24|

---

US201862635284P| true| 2018-02-26|2018-02-26|

---

US62/635,284|2018-02-26|

---

US16/198,796|US10892297B2|2017-11-27|2018-11-22|Light emitting diodestack for a display|

---

US16/198,796|2018-11-22|

---

PCT/KR2018/014734|WO2019103579A1|2017-11-27|2018-11-27|Led unit for display and display apparatus having the same|

---