KR20080050699A - Liquid crystal display device - Google Patents

Abstract

An LCD(Liquid Crystal Display) is provided to perform ACC(Accurate Color Capture) compensation on at least one of red, green and blue gamma curves in black gray such that the at least one of the red, green and blue gamma curves has a relatively high gray value to improve display quality. An LCD includes an LCD panel(400) and a driving unit(100). The LCD panel includes an array substrate, a counter substrate opposite to the array substrate, and a liquid crystal layer interposed between the array substrate and the counter substrate. The driving unit is electrically connected to the LCD panel and controls the LCD panel. The driving unit performs ACC compensation on at least one of red, green and blue gamma curves in the overall gray including black gray to maintain color balance.

Description

Liquid crystal display {LIQUID CRYSTAL DISPLAY DEVICE}

1 is a plan view conceptually illustrating a liquid crystal display according to an exemplary embodiment of the present invention.

2 is a graph showing gamma curves before ACC processing.

3 is a graph showing gamma curves after ACC processing.

FIG. 4 is an enlarged graph of part A of FIG. 3 in gamma curves by conventional ACC processing.

FIG. 5 is an enlarged graph of part A of FIG. 3 in gamma curves by the ACC process of the present invention.

<Explanation of symbols for the main parts of the drawings>

100: timing control unit 110: gamma conversion unit

120: ACC correction unit 130: control signal processing unit

200: data driver 300: gate driver

400: liquid crystal display panel 500: backlight unit

600: liquid crystal display

The present invention relates to a liquid crystal display device, and more particularly, to a liquid crystal display device having improved display quality of an image.

In general, a liquid crystal display device has a thin thickness, light weight, and low power consumption, and thus is mainly used for a monitor, a notebook, a mobile phone, and the like. The liquid crystal display device is a liquid crystal display panel for displaying an image by using the light transmittance of the liquid crystal, a backlight unit disposed under the liquid crystal display panel to provide light to the liquid crystal display panel and electrically connected to the liquid crystal display panel And a driving unit controlling the liquid crystal display panel.

The liquid crystal display panel includes a first substrate on which a thin film transistor and a pixel electrode are formed, a second substrate on which a color filter and a common electrode are formed, and a liquid crystal layer formed between the first and second substrates.

Meanwhile, the driving unit controls the liquid crystal display panel through an ACC (Accurate Color Capture) compensated signal to maintain color balance.

However, in the conventional liquid crystal display panel, even when the image is displayed using the ACC-compensated signal, the color of the display image when viewed from the front and when viewed from the side is different from each other. In particular, although the liquid crystal display panel of the related art implements a black image on the front side, there is a problem of realizing a black image in which red light is mixed on the side surface.

Accordingly, the technical problem of the present invention is to solve such a conventional problem, and an object of the present invention is to provide a liquid crystal display device which further improves the display quality of an image by preventing color change according to a viewing angle.

The liquid crystal display according to the embodiment for achieving the above object of the present invention includes a liquid crystal display panel and a driving unit.

The liquid crystal display panel includes an array substrate, an opposing substrate facing the array substrate, and a liquid crystal layer interposed between the array substrate and the opposing substrate.

The driving unit is electrically connected to the liquid crystal display panel to control the liquid crystal display panel, and includes at least one of red, green, and blue gamma curves including black gray to maintain color balance. ACC (Accurate Color Capture) compensation processing in all areas grayscale.

Preferably, at least one of the red, green, and blue gamma curves is compensated to have a brightness of a higher gray level than the other two curves in the black gray level. For example, the blue gamma curve is the red color in the black gray level. The gamma curve and the green gamma curve are compensated to have a higher luminance.

According to the present invention, according to the ACC compensation process in the whole area grayscale including the black grayscale, it is possible to prevent the color of the black image from changing according to the viewing angle, and as a result, the display quality of the image can be further improved.

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

1 is a plan view conceptually illustrating a liquid crystal display according to an exemplary embodiment of the present invention.

Referring to FIG. 1, the liquid crystal display 600 according to the present exemplary embodiment includes a timing controller 100, a data driver 200, a gate driver 300, a liquid crystal display panel 400, and a backlight unit 500. do.

The timing controller 100 receives the RGB image signals RD1, GD1, BD1 and the main control signal MCON from an external graphic controller (not shown). The timing controller 100 outputs the RGB driving signals RD3, GD3, and BD3 by performing ACC (Accurate Color Capture) correction processing on the RGB image signals RD1, GD1, and BD1, and outputs the data in response to the external control signal MCON. The control signal DCON and the gate control signal GCON are output. Meanwhile, a detailed description of the timing controller 100 will be described later.

The data driver 200 receives the data control signal DCON from the timing controller 100 and outputs the data signal DS to the liquid crystal display panel 400.

The gate driver 300 receives the gate control signal GCON from the timing controller 100 and outputs the gate signal GS to the liquid crystal display panel 400.

The liquid crystal display panel 400 receives the data signal DS and the gate signal GS from the data driver 200 and the gate driver 300, respectively, and displays an image using light. The liquid crystal display panel 400 includes an array substrate, a counter substrate (not shown) facing the array substrate, and a liquid crystal layer (not shown) interposed between the array substrate and the counter substrate.

Specifically, for example, the array substrate may include a gate line GL formed in a first direction, a data line DL formed in a second direction perpendicular to the first direction, a gate line GL, and data. The thin film transistor TFT may be electrically connected to the wiring DL and the pixel electrode PE may be electrically connected to the thin film transistor.

Meanwhile, the pixel electrode PE is made of a transparent conductive material and includes a first pixel portion and a second pixel portion to which voltages of different levels are applied to further improve the viewing angle. That is, a first voltage may be applied to the first pixel portion, and a second voltage having a level lower than the first voltage may be applied to the second pixel portion.

The opposing substrate includes a color filter expressing color, a common electrode made of a transparent conductive material, and a light shielding film covering the gate line GL, the data line DL, the thin film transistor TFT, and the like. In this case, the color filter includes a red color filter, a green color filter, and a blue color filter.

The liquid crystal layer is interposed between the array substrate and the counter substrate, the arrangement is changed by an electric field formed between the pixel electrode PE and the common electrode, thereby changing the light transmittance.

The backlight unit 500 is disposed under the liquid crystal display panel 400 to provide light to the liquid crystal display panel 400. That is, the backlight unit 500 includes a lamp (not shown) that generates light to provide light to the liquid crystal display panel 400.

Next, the timing controller 100 will be described in more detail. The timing controller 100 includes, for example, a gamma converter 110, an ACC corrector 120, and a control signal processor 130.

2 is a graph showing gamma curves before ACC processing.

1 and 2, the gamma converter 110 may convert RGB image signals RD1, GD1, and BD1, that is, a red image signal RD1, a green image signal GD1, and a blue image from the external graphic controller. The signal BD1 is applied.

Specifically, the gamma converter 110 includes a red gamma converter, a green gamma converter, and a blue gamma converter.

The red gamma converter receives the red image signal RD1, converts the red image signal RD1 according to the red gamma curve R_CV, and outputs a red intermediate signal RD2.

The green gamma converter receives the green image signal GD1, converts the green image signal GD1 according to the green gamma curve G_CV, and outputs a green intermediate signal GD2.

The blue gamma converter receives the blue image signal BD1, converts the blue image signal BD1 according to the blue gamma curve B_CV, and outputs a blue intermediate signal BD2.

On the other hand, the blue gamma curve (B_CV), the green gamma curve (G_CV), and the red gamma curve (R_CV) all have a light transmittance of zero in black gray and a light transmittance in white gray. 100.

On the other hand, the blue gamma curve (B_CV), the green gamma curve (G_CV), and the red gamma curve (R_CV) are gray scales in all regions except black gray and white gray, and as gray scales increase. The transmittance gradually increases. Specifically, if the blue gamma curve (B_CV), the green gamma curve (G_CV) and the red gamma curve (R_CV) are compared with each other, the blue gamma curve (B_CV), the green gamma curve (G_CV), and the red gamma curve (R_CV) in order. It has a light transmittance value.

Here, the high light transmittance means that the luminance is high, and is equivalent to having a high gradation value. That is, a light transmittance of zero means a lowest gray scale value, and a light transmittance of 100 means a maximum gray scale value. For example, when the light transmittance is divided into 256 equal to 0 to 255 gradations, the lowest gradation value is 0 gradation and the maximum gradation value is 255 gradation.

Therefore, the blue gamma curve B_CV, the green gamma curve G_CV, and the red gamma curve R_CV all have luminance of 0 gray in black gray and 255 gray brightness in white gray. Have Also, in the gray scales of all regions except black gray and white gray, the blue gamma curve B_CV, the green gamma curve G_CV, and the red gamma curve R_CV are the blue gamma curve B_CV. , Green gamma curve G_CV and red gamma curve R_CV in order of high gray value.

3 is a graph showing gamma curves after ACC processing.

1 and 3, the ACC corrector 120 receives a red intermediate signal RD2, a green intermediate signal GD2, and a blue intermediate signal BD2 from the gamma converter 110, and converts the same. The red driving signal RD3, the green driving signal GD3, and the blue driving signal BD3 are outputted.

Specifically, the ACC corrector 120 compensates for at least one of the red gamma curve (R_CV), the green gamma curve (G_CV), and the blue gamma curve (B_CV) in the entire area grayscale including the black grayscale. Red intermediate signal RD2, green intermediate signal GD2 and blue intermediate signal BD2 are converted based on the compensated red gamma curve R_CV, green gamma curve G_CV, and blue gamma curve B_CV. The driving signal RD3, the green driving signal GD3, and the blue driving signal BD3 are outputted.

Here, the ACC (Accurate Color Capture) correction processing is a correction technique designed to maintain or maintain color balance even when the gray level is changed by reducing or eliminating the phenomenon in which color characteristics are shifted according to the gray level change. Say.

2 and 3, the changes of the red gamma curve R_CV, the green gamma curve G_CV, and the blue gamma curve B_CV before and after the ACC processing compensation process will be briefly described.

First, the green gamma curve G_CV is almost the same before or after the ACC processing compensation process. However, the red gamma curve R_CV is changed to have a higher luminance than the green gamma curve G_CV after the ACC processing compensation process, and the blue gamma curve B_CV is lower than the green gamma curve G_CV after the ACC processing compensation process. It is changed to have a luminance of gradation.

That is, ACC compensated red gamma curve (R_CV), green gamma curve (G_CV), and blue gamma curve (B_CV) are high gray values in order of red gamma curve (R_CV), green gamma curve (G_CV), and blue gamma curve (B_CV). Has

On the other hand, a more detailed description of the ACC compensation red gamma curve (R_CV), green gamma curve (G_CV) and blue gamma curve (B_CV) will be described later using a separate drawing.

The control signal processor 130 receives the main control signal MCON from an external graphic controller (not shown), and outputs a data control signal DCON and a gate control signal GCON in response thereto. Although not shown in the drawings, the control signal processor 130 may control the gamma converter 110 and the ACC corrector 120.

The timing controller 100 described above is described as an example, and may be changed to another structure. That is, the timing controller 100 controls the data driver 200 and the gate driver 300, but compensates for ACC in all region grayscales including at least one of red, green, and blue gamma curves to maintain color balance. What is necessary is just to have a structure to process.

4 is an enlarged graph of part A of FIG. 3 in gamma curves by the conventional ACC process, and FIG. 5 is an enlarged view of part A of FIG. It is a graph.

With reference to Figures 4 and 5 will be described in more detail the core content of the present invention.

First, with reference to FIG. 4, the gamma curves of the conventional ACC compensation process will be described. The red gamma curve R_CV, the green gamma curve G_CV, and the blue gamma curve B_CV are luminance of zero gray scale in the black gray scale. The luminance of the gray level is high in the order of the red gamma curve R_CV, the green gamma curve G_CV, and the blue gamma curve B_CV in all region gray scales except for the black gray scale.

Next, the gamma curves by the ACC compensation process of the present invention will be described with reference to FIG. 5. The red gamma curve R_CV and the green gamma curve G_CV have luminance of zero gray scale in the black gray scale, but the blue gamma curve. (B_CV) has a luminance of gray level higher than zero gray level in the black gray level. For example, the blue gamma curve B_CV has a luminance of 2.5 to 3.4 gradations in the black gradations.

That is, the blue gamma curve B_CV has a gray level higher than the red gamma curve R_CV and the green gamma curve G_CV near the black gray level.

On the other hand, in the whole area grayscale except for the black gradation, the luminance of the gray level is high in the order of the red gamma curve R_CV, the green gamma curve G_CV, and the blue gamma curve B_CV.

As such, the reason why the ACC correction process is performed such that the blue gamma curve B_CV has a higher gray value than the red gamma curve R_CV and the green gamma curve G_CV near the black gray level is that the conventional LCD is black when viewed from the side. This is because red color is mixed with black image near gray level.

In other words, in order to compensate for the problem that the black image is mixed with red light at the side view angle, the blue luminance is increased relative to the red luminance. To realize this, the blue gamma curve (B_CV) is increased to the red gamma near the black gray scale. An ACC correction process is performed to have a gray value higher than the curve R_CV and the green gamma curve G_CV.

On the other hand, when the black image is mixed with blue light at the side or front viewing angle, the red gamma curve R_CV is higher than the blue gamma curve B_CV and the green gamma curve G_CV near the black gray level. The ACC correction process may be performed.

As a result, according to the present exemplary embodiment, at least one of the red gamma curve (R_CV), the green gamma curve (G_CV), and the blue gamma curve (B_CV) in the black grayscale is subjected to ACC correction so as to have a relatively high grayscale value, thereby reducing color in the black image. This change can be solved.

In addition, since the problem that the color is changed in the black image can be solved only by the ACC correction process, there is a cost saving effect by omitting the change of the liquid crystal display panel itself such as the change of the lamp and the change of the color filter thickness.

Meanwhile, in the present invention, in order to solve the problem of changing the color in the black image, the ACC correction process is performed in black gray. Alternatively, in order to solve the problem in which the color is changed in the white image, the ACC correction is performed in the same concept as described above in the white gray. Can be processed.

According to the present invention, it is possible to solve the problem of changing the color in the black image by performing ACC correction processing such that at least one of the red gamma curve, the green gamma curve, and the blue gamma curve has a relatively high gray value in the black gray scale. As a result, the display quality of the image may be further improved.

In the detailed description of the present invention described above with reference to a preferred embodiment of the present invention, those skilled in the art or those skilled in the art having ordinary knowledge in the scope of the invention described in the claims to be described later It will be understood that various modifications and variations can be made in the present invention without departing from the scope of the present invention.

Claims (7)

A liquid crystal display panel having an array substrate, an opposing substrate facing the array substrate, and a liquid crystal layer interposed between the array substrate and the opposing substrate; And At least one of red, green, and blue gamma curves in a full gray scale including black gray to be electrically connected to the liquid crystal display panel to control the liquid crystal display panel and to maintain color balance. A liquid crystal display device comprising a drive unit for accelerating Accurate Color Capture (ACC) compensation. The liquid crystal display of claim 1, wherein at least one of the red, green, and blue gamma curves is compensated to have a higher luminance in the black gray level than the other two curves. The liquid crystal display device of claim 2, wherein the blue gamma curve is compensated to have a luminance higher than that of the red gamma curve and the green gamma curve in the black gray level. The liquid crystal display of claim 3, wherein the red gamma curve and the green gamma curve have a luminance of 0 gray in the black gray. The liquid crystal display of claim 4, wherein the blue gamma curve is compensated to have a luminance of 2.5 to 3.4 grayscales in the black grayscale. The method of claim 1, wherein the drive unit A timing controller configured to receive an RGB image signal from an external source and perform ACC compensation to output an RGB driving signal, and to receive an external control signal to output a data control signal and a gate control signal; A data driver which receives the data control signal and outputs a data signal to the liquid crystal display panel; And And a gate driver configured to receive the gate control signal and output a gate signal to the liquid crystal display panel. The method of claim 6, wherein the timing controller A gamma converter converting the RGB image signal according to the red, green, and blue gamma curves and outputting an RGB intermediate signal; An ACC corrector configured to convert the RGB intermediate signal into at least one of the red, green, and blue gamma curves according to an ACC-process compensated gamma curve in all area grays including the black grays to output the RGB driving signal; And And a control signal processor configured to output the data control signal and the gate control signal in response to the external control signal.

Images