KR20060011140A - Liguid crystal display device and method for driving the same - Google Patents

Abstract

Disclosed is a liquid crystal display device which improves horizontal phenomena by making the odd data charging amount and the even data charging amount the same.

The liquid crystal display of the present invention generates a first control signal for driving a gate and a second control signal for driving a data, and has a first width and a first width having a different width based on a GOE signal included in the first control signal. A control unit for generating 2 GOE signals; A gate driver sequentially supplying first and second scan signals having different widths in response to the first control signal and the first and second GOE signals; A data driver that polarizes and supplies a predetermined data signal in response to the second control signal; And a liquid crystal panel displaying the data signal.

2-dot Inversion, Gate Output Enable, Horizontal Line

Description

 Liquid crystal display device and method for driving the same {Liguid crystal display device and method for driving the same}

1 is a view showing a conventional liquid crystal display device.

FIG. 2 is a driving waveform diagram of the liquid crystal display shown in FIG.

3A and 3B illustrate polar patterns of data signals supplied to liquid crystal cells of a liquid crystal panel by a 2-dot inversion method.

4A and 4B are diagrams showing a horizontal line phenomenon by a 2-dot inversion driving method.

5 is a diagram illustrating a two-dot inversion liquid crystal display device according to an exemplary embodiment of the present invention.

FIG. 6 is a generation waveform diagram of a GOE_A signal of the 2-dot inversion liquid crystal display shown in FIG. 5;

FIG. 7 is a generation waveform diagram of a GOE_B signal of the 2-dot inversion liquid crystal display shown in FIG. 5;

FIG. 8 is a driving waveform diagram of the liquid crystal display shown in FIG. 5;

<Description of Signs of Major Parts of Drawings>

12 liquid crystal panel 14 gate driver                 

16: data driver 20: control unit

21: data alignment unit 22: timing controller

23: GOE generation unit 23a: the first GOE generation unit

23b: second GOE generator 25: control signal generator

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device, and more particularly, to a liquid crystal display device and a driving method thereof capable of preventing a horizontal line phenomenon generated in a two-dot inversion driving method.

Conventional liquid crystal display devices display an image by adjusting the light transmittance of the liquid crystal 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, and a driving circuit for driving the liquid crystal panel.

As shown in FIG. 1, a conventional liquid crystal display device includes a liquid crystal panel 2 in which liquid crystal cells are arranged in a matrix, and a gate driver for driving gate lines GL1 to GLn of the liquid crystal panel 2. (4), a data driver 6 for driving the data lines DL1 to DLn of the liquid crystal panel 2, a timing controller for controlling the gate driver 4 and the data driver 6 (10) is provided.

The liquid crystal panel 2 is formed at each intersection of the liquid crystal cells arranged in a matrix form and the gate lines GL1 to GLn and the data lines DL1 to DLm, and is connected to each of the liquid crystal cells. (TFT).

The thin film transistor TFT is turned on when the scan signal from the gate line GL, that is, the gate high voltage VGH is supplied, and supplies the pixel signal from the data lines DL1 to DLm to the liquid crystal cell. The thin film transistor TFT is turned off when the gate low voltage VGL is supplied from the gate lines GL1 to GLn to maintain the pixel signal charged in the liquid crystal cell.

The liquid crystal cell is equivalently represented by a liquid crystal capacitor Clc, and includes a common electrode facing the liquid crystal and a pixel electrode connected to the thin film transistor TFT. The liquid crystal cell further includes a storage capacitor Cst so that the charged pixel signal is stably maintained until the next pixel signal is charged. The storage capacitor Cst is formed between the previous gate line and the pixel electrode. The liquid crystal cell realizes gradation by adjusting light transmittance by varying an arrangement state of liquid crystal having dielectric anisotropy according to a pixel signal charged through a thin film transistor (TFT).

The gate driver 4 sequentially supplies the gate high voltage VGH to the gate lines GL1 to GLn in response to the gate control signals GSP, GSC, and GOE from the timing controller 10. Accordingly, the gate driver 4 causes the thin film transistor TFT connected to the gate lines GL1 to GLn to be driven in units of the gate lines GL1 to GLn.

Specifically, the gate driver 4 shifts the gate start pulse GSP according to the gate shift pulse GSC, and is output by the control of the gate output enable signal GOE. In response to the gate shift pulse, the gate driver 4 supplies the gate high voltage VGH to the corresponding gate line GL for each horizontal section H1, H2, H3 .. as shown in FIG. 2. do. In this case, the gate driver 4 supplies the gate high voltage VGH under the control of the GOE as shown in FIG. 2. The gate driver 4 supplies the gate low voltage VGL to the gate lines GL1 through GLn in the remaining periods when the gate high voltage VGH is not supplied. In addition, the gate driver 4 supplies a gate low voltage VGL to the gate line GL0 formed at the uppermost side for the storage capacitor Cst of the first scan line.

The data driver 6 outputs a pixel signal of one line for each horizontal section H1, H2, H3 .. in response to the data control signals SSP, SSC, SOE, and POL from the timing controller 10. Supply to the data lines DL1 to DLm. In particular, the data driver 6 converts and supplies the digital pixel data R, G, and B from the timing controller 10 into an analog pixel signal.

Specifically, the data driver 6 generates a sampling signal by shifting the source start pulse SSP according to the source shift clock SSC. Subsequently, the data driver 6 sequentially inputs and latches the video data signals R, G, and B in predetermined units in response to the sampling signal. The data driver 6 converts the latched pixel data R, G, and B for one line into an analog pixel signal and supplies the same to the data lines DL1 through DLm. In this case, the data driver 6 converts the positive and negative pixel signals in response to the polarity control signal POL. For example, as illustrated in FIG. 2, the data driver 6 has a polarity in which a pixel signal (Source Output) is polarized in a vertical two-dot inversion scheme in response to a polarity control signal POL that is polarized inverted every two horizontal periods. Let it be reversed. The data driver 6 supplies the pixel signals to the data lines DL to DLm only during the enable period under the control of the source output enable signal SOE as shown in FIG. 2.

The timing controller 10 generates gate control signals GSP, GSC, and GOE to control the gate driver 4, and generates data control signals SSP, SSC, SOE, and POL to generate the data driver. (6) will be controlled. In addition, the timing controller 10 aligns the pixel data R, G, and B to the data driver 6.

As such, the liquid crystal display uses an inversion method to prevent degradation of the liquid crystal cells and to improve image quality. The vertical two-dot inversion method is used to complement the dot inversion method, which consumes a lot of power. In other words, the dot inversion method causes flicker when the frame frequency is lowered from 50Hz to 30Hz in order to reduce power consumption. In order to compensate for this, the vertical 2 dots are illustrated in FIGS. 3A and 3B. The inversion method is used.

3A and 3B illustrate a pixel signal polarity supplied to liquid crystal cells in a vertical 2-dot inversion scheme divided into odd and even frames.

In the odd and even frames shown in Figs. 3A and 3B, the vertical two-dot inversion scheme changes the polarity of the pixel signal in the unit of dots in the horizontal direction as in the conventional dot inversion scheme, while in the vertical direction. You can see that it is driven to change by 2 dots. The vertical two-dot inversion method has the advantage that the flicker phenomenon is reduced in comparison with the dot inversion method in a commercial screen driven at a frame frequency of 60 Hz, but has a problem in that horizontal lines occur due to the luminance difference every two scanning lines. .

4A and 4B illustrate horizontal lines in the odd frame and even frame shown by the vertical two-dot inversion method.

4A and 4B, when the polarity of the liquid crystal cell is changed in units of 2 dots vertically, a horizontal line phenomenon occurs due to the luminance difference between the odd scan lines G1 and the even scan lines G2. This is because the charging characteristics of the data signal in the even-numbered scan line G2 to which the odd-numbered scan line is adjacent and the data voltage signal of the same polarity are supplied are different in the vertical 2-dot inversion method.

In detail, as shown in FIG. 2, when the gate high voltage VGH applied to the odd gate lines GL1 and GL3 .. and the pixel signals applied to the data lines DL1 to DLm are turned on, respectively. In the case where the charged data charging amount A and the gate high voltage VGH applied to the even gate lines GL2 and GL4 .. and the pixel signals applied to the data lines DL1 to DLm are turned on, respectively, A difference occurs in the data charging amount B to be charged. That is, the gate charging amount charged in the odd gate lines GL1 and GL3 .. is less than the gate charging amount charged in the even gate lines GL2 and GL4 ... As a result, a horizontal line phenomenon in which the superior gate lines DL1 to DLn appear brighter than the odd gate lines GL1 to GLn occurs, resulting in poor image quality.

 Accordingly, an object of the present invention is to provide a liquid crystal display device and a driving method thereof capable of preventing the horizontal line phenomenon by equalizing the odd data charging amount and the even data filling amount.

According to a preferred embodiment of the present invention for achieving the above object, the liquid crystal display generates a first control signal for driving the gate and the second control signal for driving the data, GOE included in the first control signal A controller for generating first and second GOE signals having different widths based on the signal, and first and second scan signals having different widths in response to the first control signal and the first and second GOE signals. And a gate driver for sequentially supplying N, a data driver for inverting and supplying a predetermined data signal in response to the second control signal, and a liquid crystal panel for displaying the data signal.

According to another preferred embodiment of the present invention, the driving method of the liquid crystal display device generates a first control signal for driving a gate and a second control signal for driving data, and generates a GOE signal included in the first control signal. Generating first and second GOE signals having different widths based on each other, and sequentially performing first and second scan signals having different widths in response to the first control signal and the first and second GOE signals. And supplying the data signal by inverting a predetermined data signal in response to the second control signal, and displaying the data signal.

Hereinafter, exemplary embodiments of the present invention will be described with reference to the accompanying drawings.                     

5 is a block diagram illustrating a two-dot inversion liquid crystal display device according to an exemplary embodiment of the present invention.

Referring to FIG. 5, the liquid crystal display of the present invention generates GSP, GSC, GOE, etc. (hereinafter referred to as the first control signal), and SSP, SSC, SOE, POL, etc. (hereinafter referred to as second control signal). The control unit 20 includes a control signal generator 25 to generate and a GOE generator 23 to generate a first GOE signal GOE_A and a second GOE signal GOE_B having different widths using the GOE. ), A gate driver 14 for supplying scan signals having different widths in response to the first control signal and the first and second GOE signals, and a polarity in units of 2 dots in response to the second control signal. A data driver 16 for supplying the inverted data signal and a liquid crystal panel 12 for displaying the data signal.

The controller 20 may include a data alignment unit 21 for aligning and supplying digital data R, G, and B to the data driver 16, and a timing controller 22 for generating first and second control signals. It includes. The timing controller 22 uses the control signal generator 25 to generate the first control signal and the second control signal, and the first GOE signal using the GOE signal generated by the control signal generator 25. GOE_A) and a GOE generation unit 23 for generating the second GOE signal GOE_B.

Here, the technique for generating the first and second control signals is already well known, and further description thereof will be omitted.

The GOE generator 23 includes a first GOE generator 23a for generating the first GOE signal GOE_A and a second GOE generator 23b for generating the second GOE signal GOE_B. .

As shown in FIG. 6, the first GOE generation unit 23a multiplies the first masking signal by the GOE signal generated by the control signal generation unit 25, except that signal values of each other are high. Let all output low. For example, when the GOE signal and the first masking signal are High, the first GOE signal GOE_A outputs High. In addition, when the GOE signal is High and the first masking signal is Low, the first GOE signal GOE_A may be output low. Therefore, the first GOE signal GOE_A is output every odd number.

As shown in FIG. 7, the second GOE generation unit 23b multiplies the second masking signal by the GOE signal generated by the GOE generation unit 23 and all except the signal values of each other are high. Output low. For example, when the GOE signal and the second masking signal are High, the second GOE signal GOE_A outputs High. In addition, when the GOE signal is High and the second masking signal is Low, the second GOE signal GOE_B may be output low.

Here, the second GOE signal GOE_B generated by the second GOE generator 23b has a width larger than that of the first GOE signal GOE_B by the GOE signal generated by the control signal generator 25. Can be set to To this end, the second GOE generator 23b increases the GOE signal generated by the control signal generator 25 to a predetermined width. In this case, it is preferable that the first masking signal and the second masking signal have opposite polarities. Therefore, the second GOE signal GOE_B is output every even-numbered second.                     

The gate driver 14 receives the first control signal (the GOE signal does not exist) from the control signal generator 25 and the first GOE signal GOE_A in the order of the odd and even numbers from the GOE generator. And a second GOE signal GOE_B.

The gate driver 14 generates a first scan signal in response to the first control signal and the first GOE signal GOE_A, and generates a second scan signal in response to the first control signal and the second GOE signal GOE_B. Create The first and second scan signals generated in this manner are sequentially supplied to the gate lines GL1 to GLn of the liquid crystal panel 12.

Widths of the first and second scan signals are different from each other. That is, the second scan signal is controlled by the second GOE signal, wherein the width of the second GOE signal is greater than the width of the first GOE signal, and inversely, the width of the second scan signal is It becomes smaller than the first scan signal.

When the scan signal is applied to each gate line GL1 to GLn in response to the second control signals from the control signal generator 25, the data driver 16 outputs the data signal by one line. DL1 to DLm). In particular, the data driver 16 converts the digital data R, G, and B from the control unit 20 into an analog data signal using a gamma voltage from a gamma voltage generator (not shown). .

Specifically, the data driver 16 shifts the source shift pulse SSP according to the source shift clock SPC to generate a sampling signal. Subsequently, the data driver 16 sequentially inputs and latches the video data signals R, G, and B in response to the sampling signal. The data driver 16 converts the latched one-pixel pixel data R, G, and B into an analog data signal and supplies the same to the data lines DL1 through DLm. The data driver 16 converts the positive and negative data signals in response to the polarity control signal POL. As shown in FIG. 8, it can be seen that the data signal is output with the polarity inverted in units of 2 dots by the polarity control signal POL.

The liquid crystal panel 12 has a scan signal (the first scan signal and the second scan signal) having different widths applied to odd-numbered and even-numbered gate lines and data signals applied to data lines. The predetermined image is implemented. At this time, the data implemented in the liquid crystal panel 12 is a scan signal (Gate output) applied to the odd and even gate lines, and a data signal (Source output) applied to the data lines as shown in FIG. Because of the same amount of data charging to be charged can be implemented to improve the problem such as the horizontal line phenomenon.

Here, the charging amount A charged by the first scan signal applied to the odd gate lines and the charging amount B charged by the second scan signal applied to even-numbered gate lines are shown in FIG. 8. As can be seen the same. Therefore, the data charging amount A charged by the first scan signal applied to the odd-numbered gate line shown in FIG. 8 and the data charging amount B charged by the second scan signal applied to the even-numbered gate line are shown. Is the same to improve the horizontal phenomenon.

As described above, the liquid crystal display according to the present invention uses the GOE signal generated by the control signal generator 25 to generate the first GOE generator 23a and the second GOE generator of the GOE generator 23. 23b) generates the odd first GOE signal GOE_A and the even second GOE signal GOE_B having different widths. The first and second scan signals having different widths are applied by the first GOE signal GOE_A and the second GOE signal GOE_B. In this case, since the respective data charging amounts charged by the first and second scan signals are equal, the image quality may be improved by eliminating the horizontal line phenomenon and the like.

As described above, according to the liquid crystal display and the driving method thereof according to the present invention, the first and second odd GOE signals GOE_A having the different widths and the second second GOE signal GOE_B supplied under the control By using the first and second scan signals, the amount of data charged in each of the odd and even numbers is equalized, thereby eliminating horizontal lines and the like, thereby improving image quality.

Claims (16)

A controller for generating a first control signal for gate driving and a second control signal for data driving, and generating first and second GOE signals having different widths based on the GOE signal included in the first control signal. ; A gate driver sequentially supplying first and second scan signals having different widths in response to the first control signal and the first and second GOE signals; A data driver that polarizes and inverts a predetermined data signal in response to the second control signal; And And a liquid crystal panel for displaying the data signal. The method of claim 1, And the first and second scan signals are sequentially supplied to odd and even gate lines of the liquid crystal panel. The method of claim 1, And the second GOE signal is wider than the first GOE signal.       The method of claim 1, And the first GOE signal is generated every odd number by the product of the GOE signal and the first masking signal. The method of claim 4, wherein And the second GOE signal increases in width of the GOE signal and is generated every even-numbered time by multiplying by the second masking signal having an opposite polarity to the first masking signal. The method of claim 1, And the first scan signal is supplied every odd number in response to the first control signal and the first GOE signal. The method of claim 1, And the second scan signal is supplied every even number in response to the first control signal and the second GOE signal. The method of claim 1, The width of the second scan signal is reduced by the increase width of the second GOE signal. Generating a first control signal for gate driving and a second control signal for data driving, and generating first and second GOE signals having different widths based on the GOE signal included in the first control signal; ; Sequentially supplying first and second scan signals having different widths in response to the first control signal and the first and second GOE signals; Inverting and supplying a predetermined data signal in response to the second control signal; And And displaying the data signal. The method of claim 9, And the first and second scan signals are sequentially supplied to odd-numbered and even-numbered gate lines of the liquid crystal panel. The method of claim 9, The second GOE signal is set to have a width larger than the first GOE signal.  The method of claim 9, And the first GOE signal is generated every odd number by the product of the GOE signal and the first masking signal. The method of claim 12, The second GOE signal is generated every second even by increasing the width of the GOE signal and multiplying the first masking signal by a second masking signal having an opposite polarity. . The method of claim 9, And the first scan signal is supplied every odd number in response to the first control signal and the first GOE signal. The method of claim 9, And the second scan signal is supplied at every even second in response to the first control signal and the second GOE signal. The method of claim 1, And a width of the second scan signal decreases by an increase width of the second GOE signal.

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