• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
  • 引用文献
  • 法律状态
  • 优先权
    • 专利摘要:
    Four contact points for transmitting voltage to the common electrode are formed at four corners of the active region, and the four contact points are separately connected to the common electrode voltage generator so that different voltages can be applied. The lead connecting the four contact points and the common electrode voltage generator connects the lead formed on the substrate with the lead formed on the substrate through the remaining pins of the integrated circuit driving the thin film transistor.
    公开号:KR19990059989A
    申请号:KR1019970080207
    申请日:1997-12-31
    公开日:1999-07-26
    发明作者:서정원
    申请人:윤종용；삼성전자 주식회사；
    IPC主号:
    专利说明:

    Liquid crystal display
    BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display, and more particularly, to a liquid crystal display capable of applying a common electrode voltage varied by a predetermined amount depending on a position on a substrate.
    Now, a liquid crystal display device according to the prior art will be described.
    The contact points are formed at regular intervals around the region where the thin film transistor and the pixel electrode are formed on the thin film transistor substrate (hereinafter, referred to as 'active regions'), and all of these contact points are electrically connected to each other. The contact points are connected to a common electrode voltage generator, and are in contact with a common electrode formed on a color filter substrate facing the thin film transistor substrate, thereby transferring a voltage applied by the common electrode voltage generator to the common electrode. do.
    In this structure, since all the contact points are connected to one, the common electrode is always subjected to a constant voltage across the entire surface.
    However, the gate line formed on the thin film transistor substrate has a resistance component and a capacitance component, and therefore the gate signal applied as a square wave to the gate line is distorted. The distortion of the gate signal increases as the gate signal input ends from the gate line end to the gate line end, because the resistance and capacitance components through which the signal passes increases. As the distortion of the gate signal becomes larger, the kick back voltage at the pixel electrode gradually decreases. Here, since the change in the kickback voltage means a change in the pixel electrode voltage, the voltage difference between the pixel electrode and the common electrode to which the same voltage is applied across the entire surface shows a different value depending on the position. However, if the difference in kickback voltage increases, the flicker of the screen also increases. Accordingly, in the conventional common electrode voltage application method, when the common electrode voltage is changed to remove flicker on one side of the screen, flicker occurs on the other side, and thus flicker of the entire screen cannot be removed.
    In order to solve this problem, a liquid crystal display device as shown in FIG. 1 is proposed.
    Referring to FIG. 1, a data line driver integrated circuit 8 connected to a printed circuit board (PCB) substrate 72 for driving a data line is disposed on a pad portion (not shown) of the data line. The gate line driver integrated circuit 9 connected to the PCB substrate 71 on the left side of the substrate 1 is connected to a pad portion (not shown) of the gate line. In the center of the substrate 1, there is an active region 2 in which a thin film transistor and a pixel electrode (not shown) are formed, and the contact points 31 are formed at the remaining three corners except for the lower right side of the four corners of the substrate 1. 32, 33) are formed. The three contact points 31, 32, 33 are respectively connected to the common electrode voltage generator 5 via the drive integrated circuits 8, 9 and the PCB substrates 71, 72 through the conductors 61, 62, 63, respectively. The common electrode voltage generator 5 may apply different voltages to the conductive wires. When the upper substrate (not shown) on which the common electrode (not shown) is formed is covered, each contact point 31, 32, 33 contacts the common electrode, and different voltages applied by the common electrode voltage generator are applied. Can be transferred to the common electrode.
    In such a structure, different voltages may be applied to each part of the common electrode, and thus, flickering of the screen may be eliminated to some extent by adjusting the common electrode voltage. However, since the contact point is not formed at the lower right side of the substrate 1 where the distortion of the gate line signal or the data line signal is the greatest, the voltage cannot be adjusted, and thus the vicinity thereof is vulnerable to flicker of the screen.
    An object of the present invention is to eliminate screen flicker of the liquid crystal display.
    1 is a layout view of a liquid crystal display according to the related art,
    2 is a layout view of a liquid crystal display according to an exemplary embodiment of the present invention.
    3 is a diagram illustrating waveforms of a gate line signal voltage, a data line signal voltage, and a pixel electrode voltage with respect to a common electrode voltage.
    In order to solve the above problems, in the present invention, four contact points for transmitting voltage to the common electrode are formed at four corners of the active region, and the four contact points are separately connected to the common electrode voltage generator to apply different voltages. To help. In the conductive line connecting the four contact points and the common electrode voltage generator, the conductive line formed on the substrate is connected to the conductive line formed on the substrate through the remaining pins of the integrated circuit driving the thin film transistor.
    Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
    2 is a layout view of a liquid crystal display according to an exemplary embodiment of the present invention.
    The data line driving integrated circuit 80, which is connected to a printed circuit board (PCB) substrate 720 for driving data lines, is disposed on a pad portion (not shown) of a data line that transfers an image signal. The gate line driver integrated circuit 90 connected to the PCB substrate 710 for driving the gate line is connected to a pad portion (not shown) of the gate line that transmits the scan signal to the left side of the substrate 10. It is. In the center of the substrate 10 is an active region 20 in which a pixel electrode (not shown) for displaying an image signal is formed, and at four corners of the substrate 10, first to fourth contact points 310, 320, 330 and 340 are formed, and these four contact points 310, 320, 330, and 340 are connected to the common electrode voltage generator 50 through the first to fourth conductive wires 610, 620, 630, and 640, respectively. It is. The conductive wires 610, 620, 630, and 640 are provided as spare parts in the driving integrated circuits 80 and 90 via the PCB substrates 710 and 720. It is formed above and is connected to a conductor extending to the contact points 310, 320, 330, 340. The common electrode voltage generator 50 is configured to apply different voltages to the conductive wires 610, 620, 630, and 640, respectively. Therefore, when the upper substrate (not shown) is combined, the contact points 310, 320, 330, and 340 contact four corners of the common electrode (not shown) formed on the upper substrate, thereby providing the common electrode voltage generator 50. Different voltages applied by) are transmitted to the common electrode.
    The voltage applied from the common electrode voltage generator 50 is adjusted to increase gradually in the order of the first contact point 310, the second contact point 320, the third contact point 330, and the fourth contact point 330.
    The reason why the common electrode voltage is differentially applied will be described.
    First, referring to FIG. 3, the reason why the kickback voltage causes screen flicker will be described.
    When the data line voltage Vid rises from VdL to VdH and then the gate voltage Vgp rises from VgL to VgH, a channel of the thin film transistor is opened, and positive charge flows from the drain electrode to the source electrode through the channel to the pixel electrode. Accumulate. As positive charges accumulate in the pixel electrode, the pixel electrode voltage Vp gradually increases to rise to VdH. Subsequently, when the gate voltage Vgp drops from VgH to VgL, the channel of the thin film transistor is cut off, and at this moment, the voltage difference between the gate electrode and the source electrode becomes larger than the voltage difference between the pixel electrode and the common electrode, and thus accumulates in the pixel electrode. The positive charge, which has been used, is dispersed and received by the source electrode, so that the voltage Vp of the pixel electrode drops slightly. The pixel electrode voltages falling together at the moment when the gate voltage Vgp falls from VgH to VgL are referred to as kickback voltages Vk. Subsequently, when the data line voltage Vid held at VdH drops to VdL, and then the gate voltage Vgp rises from VgL to VgH, the channel of the thin film transistor is opened again, and the positive charge accumulated in the pixel electrode through this channel Spills. As the accumulated positive charge flows out, the pixel electrode voltage Vp gradually decreases to drop to VdL, whereby negative charge is distributed on the pixel electrode. Subsequently, when the gate voltage Vgp falls from VgH to VgL, the channel of the thin film transistor is cut off, and at this moment, the voltage of the gate electrode VgL becomes lower than the voltage VdL of the source electrode so that the source electrode is pulled from the pixel electrode. Positive charges accumulate. Thus, more negative charge remains on the pixel electrode, resulting in a slightly lower voltage.
    As such, the kickback voltage Vk always acts in the direction of lowering the pixel electrode voltage Vp. Therefore, as the kickback voltage Vk increases, the asymmetry between the waveforms of the pixel electrode voltage Vp that fluctuates up and down with respect to the common electrode voltage Vcom is intensified. The asymmetry of the pixel electrode voltage Vp waveform is increased. It may cause the screen flicker.
    Next, the relationship between the kickback voltage and the delay of the gate line signal will be described.
    The circuit of the thin film transistor substrate has a resistance component and a capacitance component. Therefore, the signal applied through the gate line is slightly delayed, and the degree increases from the input side to the output side. However, the delay of the gate signal means that the signal waveform does not fall vertically but falls in a curved line. That is, when the delay of the gate signal is large, the fall time of the gate signal pulse becomes long. During this time, the positive charge flows into the pixel electrode without the channel of the thin film transistor being completely blocked. In this case, as the gate voltage decreases, positive charges received at the source electrode flow through the channel instead of being drawn from the pixel electrode. Thus, the kickback voltage is reduced. As a result, the kickback voltage decreases as the delay of the gate signal increases. However, since the gate signal delay increases as the distance from the input terminal increases, the kickback voltage decreases as it moves away from the input terminal.
    Since the kickback voltage is larger at the gate line input terminal (left side in FIG. 2) and decreases toward the gate line terminal (right side in FIG. 2), the asymmetry between the pixel electrode voltage waveforms based on the common electrode voltage becomes smaller. Therefore, in order to make the pixel electrode voltage waveform with respect to the common electrode voltage symmetrical throughout the screen, the common electrode voltage near the gate line input terminal should be lowered much and the common electrode voltage near the gate line terminal should be slightly reduced. That is, the first contact point 310, the second contact point 320, the third contact point 330, and the fourth contact point 330 are adjusted to increase gradually. Here, the voltage difference between the contact point 310 in the upper left and the contact point 320 in the lower left is also taken into consideration to delay the data line signal.
    At this time, the common electrode formed of indium tin oxide (ITO) has a resistance that cannot be ignored. Therefore, when different voltages are applied to each point of the common electrode which is integrally formed, a voltage drop occurs as a current flows from a point of high voltage to a point of low according to the law of ohm. It changes with a constant slope from the high point to the low point. The voltage difference between the first to fourth contact points allows the voltage difference between the common electrode and the pixel electrode to be constant throughout the screen, and the pixel electrode voltage inverted up and down on the basis of the common electrode voltage is vertically symmetrical. Adjust
    In this way, a change in the voltage difference between the pixel electrode and the common electrode in each part of the substrate due to the delay of the gate line signal and the data line signal can be compensated by changing the common electrode voltage. The screen flicker can be eliminated.
    权利要求:
    Claims (3)
    [1" claim-type="Currently amended] First substrate,
    A gate line pad unit formed on the first substrate and connected to a gate line driving circuit to transfer a scan signal;
    A data line pad unit formed on the first substrate and connected to a data line driving circuit to transfer an image signal;
    An active region formed on the first substrate and composed of a plurality of pixels for displaying the image signal,
    A second substrate facing the first substrate,
    A common electrode formed on a surface of the second substrate facing the first substrate,
    A contact point formed adjacent to four corners of the active region of the first substrate and in electrical contact with the common electrode,
    And a common electrode voltage generator connected separately to the four contact points and capable of applying different voltages to the four contact points.
    [2" claim-type="Currently amended] In claim 1,
    The conductive line connecting the four contact points and the common electrode voltage generator is connected to a conductive line formed on the substrate and a conductive line formed on the substrate through the remaining pins of the driving integrated circuit attached to the substrate.
    [3" claim-type="Currently amended] The method of claim 1 or 2,
    The voltage applied by the common electrode voltage generator to the contact point is highest at the contact point furthest from both the data line pad portion and the gate line pad portion, and is second from the contact point close to the data line pad portion and far from the gate line pad portion. A third liquid crystal that is high at a third point at a contact point far from the data line pad portion and close to the gate line pad portion, and has a lowest value at a contact point closest to both the data line pad portion and the gate line pad portion. Display device.
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    同族专利:
    公开号 | 公开日
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    法律状态:
    1997-12-31|Application filed by 윤종용, 삼성전자 주식회사
    1997-12-31|Priority to KR1019970080207A
    1998-07-15|Priority claimed from KR1019980028547A
    1999-07-26|Publication of KR19990059989A
    优先权:
    申请号 | 申请日 | 专利标题
    KR1019970080207A|KR19990059989A|1997-12-31|1997-12-31|Liquid crystal display|
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