KR20050087481A - Liquid crystal display device - Google Patents

Abstract

The present invention discloses a liquid crystal display device which can improve screen quality by feeding back a distorted gate signal on a liquid crystal panel to a driving circuit unit to compensate for the distorted gate signal. According to an aspect of the present invention, there is provided a liquid crystal display including a liquid crystal panel and a driving circuit unit for applying various driving signals and data signals to the liquid crystal panel, the liquid crystal panel being defined as an active region and a pad region, and a liquid crystal panel on the active region. A plurality of data lines formed in a first direction, a plurality of gate lines formed in a direction crossing the first direction on the liquid crystal panel of the active region, and a liquid crystal panel formed on the liquid crystal panel of the active region, And a dummy line for feeding back the distorted gate signal to the driving circuit unit outputting the gate signal.

Description

Liquid crystal display {LIQUID CRYSTAL DISPLAY DEVICE}

The present invention relates to a liquid crystal display device, and more particularly, to a liquid crystal display device suitable for compensating distortion of a gate signal to improve screen quality.

In general, a liquid crystal display device displays an image by adjusting a light transmittance of a liquid crystal having dielectric anisotropy using an electric field.

To this end, the liquid crystal display includes a liquid crystal panel in which liquid crystal cells are arranged in a matrix to display an image, and a driving circuit for driving the liquid crystal panel.

The driving circuit may include a gate driver IC for driving gate lines of a liquid crystal panel, a data driver IC for driving data lines, a timing controller for supplying timing control signals and pixel data to the gate driver IC and the data driver IC. And a power supply unit for supplying a power supply voltage.

The data driver IC and the gate driver IC are divided into a plurality of integrated circuits (hereinafter, referred to as ICs), integrated, manufactured in a chip form, and each integrated driver IC is mounted on a tape carrier package (TCP). And electrically connected to the liquid crystal panel by a tape automated bonding (TAB) method.

In addition, unlike the above, the timing controller and the power supply unit may be manufactured in a chip form and mounted on a printed circuit board (PCB), and the driver IC may be directly mounted on a liquid crystal panel in a chip on glass (COG) method.

Here, the driver ICs mounted on the liquid crystal panel in the COG method are timing control signals from a timing controller mounted on the PCB through line-on-glass signal lines mounted on the FPC and the liquid crystal panel. And the power supply voltage from the pixel data and the power supply unit.

In such a liquid crystal display, the timing signal, pixel data, and power supply voltage supplied to the driver IC are affected by the high impedance of the LOG signal line.

Hereinafter, a liquid crystal display according to the related art will be described with reference to the accompanying drawings.

1 is a configuration diagram of a liquid crystal display device according to the prior art, and includes a liquid crystal panel 1, an X-PCB 3, a Y-PCB 5, and the X-PCB 3 and Y-PCB ( It is configured to include a FPC (7) for electrically connecting 5).

Here, the X-PCB 3 and the liquid crystal panel 1 are connected by the X-TAB 9, and the Y-PCB 5 and the liquid crystal panel 1 are connected by the Y-TAB 11. The data driver IC 13 is configured on the X-TAB 9, and the gate driver IC 15 is configured on the Y-TAB 11.

In the liquid crystal display device having such a structure, the power supply and the signal line 17 for driving the gate are wired on the FPC 7 and the Y-PCB 5, and the driving for driving the gate line of the liquid crystal panel 1 is actually performed. The signal is applied to the liquid crystal panel 1 via the X-PCB 3? FPC 7? Y-PCB 5? Gate driver IC 15.

Meanwhile, unlike the structure of FIG. 1, a liquid crystal display device having a structure without FPC and Y-PCB has been proposed, and the structure thereof is shown in FIG. 2.

That is, the structure shown in FIG. 2 is used to connect the power and signal lines 17 wired on the FPC 7 and the Y-PCB 5 in FIG. 1 to the X-TAB 9, the liquid crystal panel 1, and the Y-. In the structure in which the FPC 7 and the Y-PCB 5 are removed by wiring on the TAB 11, the drive signal for gate driving is X-PCB (3)-X-TAB (9)-> gate driver IC (15). It is applied to the liquid crystal panel 1 via the.

Thus, when the gate driving path of the liquid crystal display device shown in FIG. 2 is represented by an equivalent circuit, it is as shown in FIG. 3, and more specifically, as shown in FIG. 4.

First, as shown in FIG. 4, D1, D2, D3,..., And Dn are data voltages to be applied to the data lines of the liquid crystal panel 1 and are respectively positively connected between adjacent lines based on the common electrode Vcom. Positive) Inverts with negative voltage and negative voltage.

In such a structure, parasitic capacitance is generated by the wiring structure of the data line and the gate line intersected with each other in the liquid crystal panel 1, whereby the gate signal applied to the gate line is distorted due to the polarity of the data voltage being reversed. Phenomenon occurs.

That is, the data signal interferes with the gate signal due to the parasitic capacitance generated between the data line and the gate line, and distortion occurs in the gate signal. The distortion of the gate signal is illustrated in FIG. 5. For reference, "A" in FIG. 5 represents a gate signal before distortion, and "B" represents a gate signal after distortion.

As such, the distortion of the gate signal due to the data signal acts as a factor of increasing or decreasing the magnitude of the data signal applied to the unit pixel of the liquid crystal display, thereby distorting the screen displayed on the pixel relative to the input data. This causes a problem of significantly degrading the screen quality.

This phenomenon can be improved to some extent by reducing the value of the resistor (R) shown in FIG. 3, but in order to reduce the value of the resistor (R), a gate signal must be transmitted through the FPC. There has been a problem that the cost rises and additional processes such as the FPC attaching process occur.

In addition, the parasitic capacitance can be reduced by changing the design of the liquid crystal panel 1, but since the data line and the gate line are essentially arranged in a cross position, there is a limit to reducing the parasitic capacitance generated between the data line and the gate line. have.

There are also ways to reduce wiring resistance and parasitic capacitance by changing the materials of the metals used in the gate lines and data lines, but this inevitably leads to more complex manufacturing processes such as equipment and process changes. Let's do it.

Accordingly, the present invention has been made to solve the above problems, by feeding back the distorted gate signal on the liquid crystal panel to the driving circuit unit to compensate for the distorted gate signal on the liquid crystal panel without changing the process or increasing the cost, It is an object of the present invention to provide a liquid crystal display device capable of improving screen quality.

The liquid crystal display device of the present invention for achieving the above object comprises a liquid crystal panel and a driving circuit portion for applying various driving signals and data signals to the liquid crystal panel, the liquid crystal is defined as an active region and a pad region A panel, a plurality of data lines formed in a first direction on the liquid crystal panel of the active region, a plurality of gate lines formed in a direction crossing the first direction on the liquid crystal panel of the active region, and And a dummy line formed on the liquid crystal panel and feeding back the distorted gate signal on the liquid crystal panel to the driving circuit unit which outputs the gate signal.

Here, the dummy line is preferably wired in the same direction as the gate line.

The dummy line may be wired to any one of a front end of the first gate line, a rear end of the last gate line, and an arbitrary front end of the gate line between the first gate line and the last gate line. desirable.

On the other hand, the dummy line is wired to extend to the Y-TAB and X-TAB formed in the pad region, the extended dummy line is preferably wired from the output pad side of the driver IC of each TAB to the input pad side.

In addition, an auxiliary dummy line is formed in the pad area to connect the dummy lines extending to the Y-TAB and the X-TAB with the driving circuit unit, and the auxiliary dummy line is a distorted gate signal transmitted through the dummy line. Is transmitted to the driving circuit unit.

Hereinafter, a liquid crystal display of the present invention will be described with reference to the accompanying drawings.

First, in order to prevent distortion of the gate driving voltage, the liquid crystal display of the present invention is characterized by feeding back to the gate driving voltage by inverting, amplifying and attenuating the gate driving voltage.

6 is a configuration diagram of a liquid crystal display according to an exemplary embodiment of the present invention.

As shown in FIG. 6, in the liquid crystal display according to the exemplary embodiment, a dummy line for receiving feedback of a gate line signal distorted by a signal of a data line on the liquid crystal panel 100 to a driving circuit unit. Characterized by forming (200).

That is, the present invention provides a dummy on the liquid crystal panel 100 including an active region in which a screen is displayed and a pad region in which a plurality of X-TABs 300 and Y-TABs 400 are connected. A line 200 is formed, and the dummy line 200 is fed back to the driving circuit unit through the Y-TAB 300 and the X-TAB 400.

In this case, the dummy line 200 is wired in the same direction as the gate lines G1 to Gn, but before the first gate line G1 or on the liquid crystal panel 100 after the Nth gate line Gn. do. Of course, you may wire between Mth gate line and M + 1st gate line. For reference, M is any integer between 1 and N.

The dummy line 200 extends to the Y-TAB 300 and the X-TAB 400, and drives the dummy line 200 of the Y-TAB 300 and the X-TAB 400 in the pad area. The auxiliary dummy line 200a is connected to the circuit part.

Thus, FIG. 7A is a view for explaining the wiring form of the dummy line in the X-TAB according to the present invention, and FIG. 7B is a view for explaining the wiring form of the dummy line in the Y-TAB.

In the case of the X-TAB 400 in order to feed back the distorted gate signal to the driving circuit unit in the liquid crystal panel 100, as shown in FIG. 7A, the data driver IC is disposed on the output pad side of the data driver IC 71. The dummy line 200 is wired to the input pad of 71, and in the case of the Y-TAB 300, it is wired as shown in Fig. 7B.

Generally, although not shown in the drawing, the driving circuit unit outputs various timing signals and data signals to the gate driver IC and the data driver IC, and is composed of circuits such as a timing controller, a gamma voltage generator, and a power supply.

Accordingly, the driving circuit unit according to an exemplary embodiment of the present invention further includes a differential amplifier that inverts, amplifies, or attenuates the distorted gate signal, that is, the feedback signal input from the dummy line, as a gate off signal. It is configured by.

FIG. 8 illustrates a differential amplifier according to a driving circuit of the present invention, in which a distorted gate signal fed back through a dummy line 200 passes through a capacitor C and a resistor R1 to an inverting terminal of the differential amplifier 81. A negative signal is input, a gate off signal is input to a non-inverting terminal (+) of the differential amplifier 81, and finally, a dummy line 200 is connected to an output terminal of the differential amplifier 81. The amplified or attenuated signal (the distortion-compensated gate signal) is outputted by inverting the gate signal.

As described above, the liquid crystal display according to the exemplary embodiment of the present invention has a dummy formed on the liquid crystal panel 100 by distorting the gate-off signal of the thin film transistor caused by mutual interference between the gate line and the data line in the liquid crystal panel 100. The line 200 and the X-TAB 400 and the Y-TAB 300 are fed back to the driving circuit part, and the differential amplifier of the driving circuit part is inverted amplified or attenuated and output.

In this case, when the signal output from the differential amplifier 81 is used as the gate-off signal, the distortion of the gate-off signal is compensated for so that a stable gate signal can be applied to the gate lines G1 to Gn of the liquid crystal panel 100. do.

Although the preferred embodiments according to the present invention have been described above, it is clear that the present invention may use various changes, modifications, and equivalents, and that the above embodiments may be appropriately modified and applied in the same manner. Accordingly, the above description does not limit the scope of the invention as defined by the limitations of the following claims.

As described above, the liquid crystal display of the present invention has the following effects.

The display quality can be improved by preventing the data signal from being distorted due to the distortion of the gate-off signal.

Since it does not use a separate FPC, the cost can be reduced by that amount, and the FPC bonding process is not necessary, so the yield can be increased due to the simplification of the process.

1 is a block diagram of a liquid crystal display device according to the prior art.

2 is a block diagram of a liquid crystal display according to another exemplary embodiment of the prior art.

3 is an equivalent circuit diagram according to FIG.

4 is a panel configuration according to FIG.

5 is a diagram illustrating a degree of distortion of a gate signal according to FIG. 2.

6 is a block diagram of a liquid crystal display according to an exemplary embodiment of the present invention.

7A to 7B are diagrams for explaining the wiring of dummy lines in X-TAB and Y-TAB according to an embodiment of the present invention.

8 is a configuration diagram of a driving circuit according to the liquid crystal display of the present invention.

* Description of the symbols for the main parts of the drawings *

100: liquid crystal panel 200: dummy line

200a: auxiliary dummy line 300: Y-TAB

400: X-TAB

Claims (6)

A liquid crystal display device comprising a liquid crystal panel and a driving circuit unit for applying various driving signals and data signals to the liquid crystal panel. A liquid crystal panel defined by an active region and a pad region; A plurality of data lines formed in a first direction on the liquid crystal panel of the active region; A plurality of gate lines formed on the liquid crystal panel of the active area in a direction crossing the first direction; And a dummy line formed on the liquid crystal panel of the active region and feeding back a distorted gate signal on the liquid crystal panel to a driving circuit unit which outputs the gate signal. The liquid crystal display of claim 1, wherein the dummy line is wired in the same direction as the gate line. The gate line of claim 1, wherein the dummy line is any one of a front end of a first gate line, a rear end of a last gate line, and a front end of any gate line between the first gate line and the last gate line. The liquid crystal display device, characterized in that the wiring to the side. The liquid crystal display of claim 1, wherein an auxiliary dummy line is formed in the pad region to connect a dummy line formed in the active region to the driving circuit unit. The liquid crystal display of claim 1, wherein the distorted gate signal of the dummy line is fed back to the driving circuit unit through a plurality of Y-TABs and X-TABs formed in the pad area. 6. The liquid crystal display device according to claim 5, wherein the dummy line extends to the Y-TAB and the X-TAB, and the extended dummy line is wired from an output pad side of each driver IC to an input pad side.