KR20150083670A - Liquid display device - Google Patents

Abstract

The present invention relates to a liquid crystal display device including: a display panel wherein a plurality of pixels are arranged; a backlight unit which generates a first light and a second light for each unit frame section and sequentially provides the first light and the second light to the pixels; and a gamma mapping unit which receives a red image signal, a green image signal, and a blue image signal from the outside and generates first data signals and second data signals which control the pixels based on the unit frame section. The unit frame includes: a first subframe wherein the first light and the first data signals are output; and a second subframe wherein the second light and the second data signals are output. The first data signals are generated based on the red image signal and the green image signal during the first subframe. At least one of the second data signals, generated during the second subframe, is generated based on the result of comparing a gray value of the blue image signal and one of the first data signals.

Description

[0001] LIQUID DISPLAY DEVICE [0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device, and more particularly, to a time division liquid crystal display device having improved display quality.

In general, a liquid crystal display device realizes full color by a space division type. To this end, the pixels of the liquid crystal display panel each include sub-pixels, and red, green, and blue color filters corresponding to the respective sub-pixels are repeatedly arranged in the liquid crystal display panel. At this time, the unit combination of the red, green, and blue color filters serves as a minimum unit for color implementation, and full color is realized through the color difference of the red, green, and blue color filters and the difference in transmittance between the sub pixels of the liquid crystal display panel . As such, the red, green, and blue color filters are arranged in the liquid crystal display panel in different spaces. This configuration is defined as a space division method.

On the other hand, there is a time division type (Field sequential type) or a field sequential type (full-color type) in which transmittance is high and cost is low in comparison with a space division method. The time-division type liquid crystal display device obtains a full color image by sequentially lighting the red, green, and blue independent light sources periodically and applying control signals corresponding to each pixel in synchronization with the lighting period. In this case, an image can be displayed using the afterimage effect of the eye by sequentially displaying one pixel in a time-division manner without spatially dividing it into red, green, and blue pixels.

An object of the present invention is to provide a liquid crystal display device with improved display quality.

According to an aspect of the present invention, there is provided a liquid crystal display device including a display panel on which a plurality of pixels are arranged, a backlight unit for generating first and second lights for each unit frame section and sequentially providing the first and second lights to the pixels, And a gamma mapping unit operable to receive the green and blue image signals and generate first and second data signals for controlling the pixels based on the unit frame period, And a second sub-frame for outputting the second light and the second data signals, wherein the first and second sub-frames output the first and second data signals, respectively, based on the red and green image signals during the first sub- 1 data signals are generated, at least one of the second data signals generated during the second sub- Gray level of the signal and the second is produced on the basis of a result of comparing a gray level value of the first data signal.

The liquid crystal display device of the present invention can improve the display quality.

1 is a block diagram of a liquid crystal display device according to an embodiment of the present invention.
2 is a view showing the principle of full color implementation according to the time division method.
FIG. 3 is a block diagram illustrating light displayed in a pixel during the first subfield shown in FIG. 2. Referring to FIG.
4 is a block diagram illustrating light displayed in a pixel during a second subfield shown in FIG.
FIG. 5 is a block diagram illustrating the operation of the timing controller shown in FIG. 1 during a first subfield according to an embodiment of the present invention.
FIG. 6 is a block diagram illustrating the operation of the timing controller shown in FIG. 1 during a second subfield according to an embodiment of the present invention.
7 is a block diagram illustrating a gamma mapping unit included in the timing controller according to the embodiment of the present invention.
8 is a flowchart showing the operation of the timing controller according to the embodiment of the present invention.

The present invention is capable of various modifications and various forms, and specific embodiments are illustrated in the drawings and described in detail in the text. It should be understood, however, that the invention is not intended to be limited to the particular forms disclosed, but includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.

Like reference numerals are used for like elements in describing each drawing. In the accompanying drawings, the dimensions of the structures are shown enlarged from the actual for the sake of clarity of the present invention. The terms first, second, etc. may be used to describe various components, but the components should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, the first component may be referred to as a second component, and similarly, the second component may also be referred to as a first component. The singular expressions include plural expressions unless the context clearly dictates otherwise.

In the present application, the terms "comprises" or "having" and the like are used to specify that there is a feature, a number, a step, an operation, an element, a component or a combination thereof described in the specification, But do not preclude the presence or addition of one or more other features, integers, steps, operations, components, parts, or combinations thereof. Also, where a section such as a layer, a film, an area, a plate, or the like is referred to as being "on" another section, it includes not only the case where it is "directly on" another part but also the case where there is another part in between. On the contrary, where a section such as a layer, a film, an area, a plate, etc. is referred to as being "under" another section, this includes not only the case where the section is "directly underneath"

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

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

The timing controller 100 receives a plurality of video signals RGB and a plurality of control signals CTRL from the outside of the liquid crystal display device 600. The timing controller 100 converts the data format of the video signals RGB according to an interface specification with the data driver 300. The video signals RGW converted from the data format are supplied to the data driver 300.

The timing controller 100 generates a data control signal D-CS, a gate control signal G-CS in response to the control signals CTRL. Illustratively, the data control signal D-CS may include an output start signal, a horizontal start signal, and the like. The gate control signal (G-CS) may include a vertical start signal and a vertical clock bar signal. The timing controller 100 provides a data control signal D-CS to the data driver 300 and provides the gate control signal G-CS to the gate driver 200.

In addition, the timing controller 100 generates a backlight control signal (B-CS) for controlling the backlight unit 500. In the embodiment of the present invention, the timing controller 100 generates a backlight control signal (B-CS) based on a field sequential type and provides it to the backlight unit 500. For example, the timing controller 100 may generate a backlight control signal (B-CS) that sequentially and periodically lights the yellow and blue light sources during one frame.

The gate driver 200 sequentially outputs the gate signal in response to the gate control signal G-CS provided from the timing controller 100. The plurality of pixels PX11 to PXnm included in the display panel 400 can be scanned row by row and sequentially by gate signals.

The data driver 300 converts the video signals RGW into a plurality of data voltages DV1 to DVm in response to a data control signal D-CS provided from the timing controller 100. [ The output data voltages DV1 to DVm are applied to the display panel 400. [

The display panel 400 includes a plurality of gate lines GL1 to GLn, a plurality of data lines DL1 to DLm, and a plurality of pixels PX11 to PXnm.

The gate lines GL1 to GLn are arranged to intersect the data lines DL1 to DLm extending in the row direction and extending in the column direction. The gate lines GL1 to GLn are electrically connected to the gate driver 200 to receive the gate signals. The data lines DL1 to DLm are electrically connected to the data driver 300 to receive data voltages.

The pixels PX11 to PXnm are connected to the corresponding gate line GLn and the corresponding data line DLm, respectively. Illustratively, the first to third pixels PX11 to PX13 may be sub-pixels that display different colors, and may be disposed in one pixel region. For example, the first pixel PX11 may be a red pixel for displaying a red image. The second pixel PX12 may be a green pixel for displaying a green image. The third pixel PX13 may be an open pixel that directly displays a light source generated from the backlight unit 500. [

That is, the pixels PX11 to PXnm may be disposed on the display panel 400 based on the structure of the first to third pixels PX11 to PX13 that display different colors. Each of the first through third pixels PX11 through PX13 may include a thin film transistor and a liquid crystal capacitor.

In detail, the first pixel PX11 is connected to the first gate line GL1 and the first data line DL1, and receives the corresponding gate signal and the first data voltage DV1. The first pixel PX11 is turned on by the corresponding gate signal, and the turned-on first pixel PX11 displays a gray-scale image corresponding to the first data voltage DV1.

The second pixel PX12 is connected to the first gate line GL1 and the second data line DL2 to receive the corresponding gate signal and the second data voltage DV2. The second pixel PX12 is turned on by the corresponding gate signal, and the turned-on second pixel PX12 displays a gray-scale image corresponding to the second data voltage DV2.

The third pixel PX13 is connected to the first gate line GL1 and the third data line DL3 to receive the corresponding gate signal and the third data voltage DV3. The third pixel PX13 is turned on by the corresponding gate signal and the turned-on third pixel PX13 displays the image of the gray scale corresponding to the first data voltage DV1.

The backlight unit 500 is disposed on the back surface of the display panel 400 and supplies light to the display panel 400. In an embodiment, the backlight unit 500 can sequentially provide the display panel 400 with lights having different colors every frame. That is, the backlight unit 500 can sequentially output the lights having different colors, in response to the backlight control signal (B-CS) provided from the timing controller 100.

2 is a view showing the principle of full color implementation according to the time division method.

Referring to FIG. 2, the time division scheme includes first and second color filters having different colors in the display panel 100 (see FIG. 1) for full color implementation. In an embodiment, the first color filter may be a red color filter (R) with red color and the second color filter may be green color filter (G) with green color. When an area corresponding to one pixel is defined as a pixel area, red and green color filters (R, G) and an open filter (W) are formed in each pixel area. Here, the open filter W can be described as having no filter.

For example, the red color filter R is included in the first pixel area PA1, the green color filter G is included in the second pixel area PA2, and the green color filter G is opened in the third pixel area PA3. And a filter W are included.

The open filter W may be formed on one side or between any one of the red and green color filters R and G. [ The open filter W substantially transmits light provided as an area in which a color filter is not formed.

1, the backlight unit 500 shown in FIG. 1 includes a first light source 510 for generating the first color light Ly and a second light source 520 for generating the second color light Lb . Although not shown, the first light source 510 and the second light source 520 may be implemented in a plurality of units, and may be alternately arranged.

The liquid crystal display 600 (see FIG. 1) according to the present invention can display one corresponding image based on the unit frame FR. In an embodiment, a unit frame FR, which is a time unit in which one image is provided, includes two first sub-fields FD1 and a second sub-field FD2 in temporal order.

In detail, the first light source 510 may be driven in the first sub-field FD1. The first light source 510 generates the first color light Ly and provides the first color light Ly to the display panel 400. And the second light source 520 may be driven during the second sub-field FD2. The second light source 520 generates the second color light Lb and provides the second color light Lb to the liquid crystal display panel 400.

In an embodiment, the first color light Ly may be light having a yellow color, and the second color light Lb may be light having a blue color. When the first color light Ly is yellow light, the first color light Ly may include a red light and a green light component. The red light component of the first color light Ly generated from the backlight unit 500 during the first sub-field FD1 may pass through the red color filter R and be displayed as a red image. The green light component of the first color light Ly may pass through the green color filter G and be displayed as a green image. The first color light Ly can be displayed as a yellow image while passing through the open filter W. [

The second color light Lb generated from the backlight unit 500 may be displayed as a blue image through the open filter W during the second subfield FD period.

As described above, the open filter W is provided to provide a space in which the blue image can be displayed during the second subfield FD. In addition, the open filter W can remove the color separation phenomenon that may occur in the time-division manner and increase the luminance. The size of the open filter W can be determined so as to exhibit appropriate transmittance in consideration of the luminance or color of the target frame.

FIG. 3 is a block diagram illustrating light displayed in a pixel during the first subfield shown in FIG. 2. Referring to FIG. 4 is a block diagram illustrating light displayed in a pixel during a second subfield shown in FIG.

3 and 4, the pixels PX11 to PXnm correspond to the red pixel RPX corresponding to the red color filter R (see Fig. 2), the green pixel G corresponding to the green color filter G (see Fig. 2) A pixel GPX, and a white pixel WPX corresponding to the open filter W (see Fig. 2). Illustratively, the red color filter R may be disposed on the red pixel RPX. The green color filter G may be disposed above the green pixel GPX. The open filter W may be disposed on the white pixel WPX.

The red, green, and white pixels RPX, GPX, and WPX may include TFTs and liquid crystal capacitors, respectively, and may be independently driven.

In the embodiment, all of the red, green, and white pixels RPX, GPX, and WPX may be operated during the first sub-field FD1. That is, the red, green, and white pixels RPX, GPX, and WPX are respectively supplied with the corresponding data voltages DVm (see FIG. 1) from the data driver 300 (see FIG. The red, green, and white pixels RPX, GPX, and WPX are supplied with the first color light Ly (see FIG. 2) from the first light source 510 in response to the data voltage DVm.

Here, the first color light Ly output from the first light source 510 may be provided to the red, green, and white pixels RPX, GPX, and WPX through the optical member 530. To this end, the backlight unit 500 (see FIG. 1) may include an optical member 530.

The first color light Ly passes through the red, green, and white pixels RPX, GPX, and WPX, and the light transmittance is adjusted. That is, the red, green, and white pixels RPX, GPX, and WPX control the light transmittance to display the gray level corresponding to the data voltages. The first color light Ly having the light transmittance controlled through the red, green and white pixels RPX, GPX and WPX passes through the red and green color filters R and G and the open filter W, Is displayed.

The second light source 520 operates in the second sub-field FD2 so that the second color light Lb (see FIG. 2) is transmitted through the optical member 530 to the red, green and white pixels RPX, GPX , WPX). At this time, the first light source 510 is turned off. In detail, during the second sub-field FD2, the red and green pixels RPX and GPX are not operated, but the white pixel WPX is operated. That is, the red and green pixels RPX and GPX are turned off to display no image, and the white pixel WPX displays an image. Therefore, the second color light Lb does not pass through the red and green color filters R and G, but is transmitted through the open filter W and displayed as a blue image.

However, during the second sub-field FD2, the luminance of the blue image transmitted through the open filter W may be lowered due to frequency driving. For example, when the frequency is 180 Hz, the liquid crystal molecules may not be sufficiently rearranged in the image representation of the next frame by a predetermined rising time of the liquid crystal molecules in the white pixel (WPX). As a result, the luminance of the blue image transmitted through the open filter W can be lowered.

The liquid crystal display 600 according to the present invention can use Blue Ridge of the red and green color filters R and G to improve the brightness of the blue image. In this case, in the second subfield FD2, the red and green pixels RPX and GPX are operated so that the red and green color filters R and G are used for the second light source 520, 1) may be transmitted through a predetermined portion. As described above, when a predetermined portion of the blue image is transmitted through the red and green color filters R and G, the brightness of the blue image can be improved during the second sub-field FD2.

To this end, the timing controller 100 according to the present invention can control the operation of the red and green pixels RPX and GPX based on the data voltage DVm provided to the white pixel WPX.

FIGS. 5 and 6 are block diagrams illustrating the operation of the timing controller shown in FIG. 1 during first and second subfields according to an embodiment of the present invention.

Referring to FIGS. 5 and 6, the gamma mapping unit (GMA) receives image signals RGB from the outside and converts the data format of the received image signals RGB. The gamma mapping unit (GMA) outputs the video signals RGW converted from the data format to the data driver 300.

In detail, the gamma mapping unit GMA can convert the data format of the video signals RGB based on the first and second subfields FD1 and FD2. That is, the gamma mapping unit GMA generates the first to third data video signals DS1, DS2, and DS3 corresponding to the video signals RGB during the first subfield FD1. Thereafter, the gamma mapping unit GMA generates the fourth to sixth data image signals DS4, DS5, and DS6 corresponding to the image signals RGB during the second subfield FD2.

The gamma mapping unit GMA sequentially outputs the video signals RGW, that is, the first to sixth data video signals DS1 to DS6 according to the first and second subfields FD1 and FD2 And the data driver 300 in sequence.

Here, the video signals RGB may include red video signals, green video signals, and blue video signals corresponding to the red, green, and blue primary color spaces, respectively. For example, the red video signal R includes information on the red video, the green video signal G includes information on the green video, and the blue video signal B includes information on the blue video do.

The data driver 300 converts the video signals RGW converted from the data format into first through third data voltages DV1 through DV3. In detail, the data driver 300 sequentially supplies the first to third data voltages DV1 to DV3 generated during the first and second subfields FD1 and FD2 to the first to third data voltages DV1 to DV3 included in the display panel 400, And sequentially supplies them to the third pixels PX11 to PX13.

5, the first to third data video signals DS1 to DS3 are provided to the data driver 300 during the first subfield FD1.

During the first subfield FD1, the first to third data video signals DS1 to DS3 are converted into the first to third data voltages DV1 to DV3 by the data driver 300, respectively. Here, the first to third data voltages DV1 to DV3 may be provided in a one-to-one correspondence with the first to third pixels PX11 to PX13.

Referring to FIG. 6, during the second subfield FD2, the fourth to sixth data video signals DS4 to DS6 are provided to the data driver 300. FIG.

During the second subfield FD2, the fourth to sixth data video signals DS4 to DS6 are converted into the first to third data voltages DV1 to DV3 by the data driver 300, respectively. Likewise, the first to third data voltages DV1 to DV3 generated during the second sub-field FD2 may be provided in a one-to-one correspondence to the first to third pixels PX11 to PX13.

As described above, the gamma mapping unit GMA can control the data voltages provided to the first to third pixels PX11 to PX13 based on the first and second subfields FD1 and FD2 have. In particular, in the second subfield FD2, the gamma mapping unit GMA generates the fourth and fifth data video signals DS4 and DS5 so that the first and second pixels PX11 and PX12 are operated . Here, the first pixel PX11 may be a red pixel RPX (see FIG. 4), and the second pixel PX12 may be a green pixel GPX. Thus, blue ridge can be generated from the first and second pixels PX11 and PX12.

7 is a block diagram illustrating a gamma mapping unit included in the timing controller according to the embodiment of the present invention.

Referring to FIG. 7, the gamma mapping unit (GMA) includes a first mapping unit MA1 and a second mapping unit MA2. The first mapping unit MA1 generates the first to third data video signals DS1 to DS3 provided to the data driver 300 (see FIG. 5) during the first subfield FD1 (see FIG. 3) . The second mapping unit MA2 generates the fourth to sixth data image signals DS4 to DS6 provided to the data driver 300 during the second subfield FD2 (see FIG. 4).

In detail, the first mapping unit MA1 receives the red and green image signals R, G. The first mapping unit MA1 generates the first to third data video signals DS1 to DS3 based on the red and green video signals R and G. [

The second mapping unit MA2 receives the first and second data video signals DS1 and DS2 and the blue video signal B from the first mapping unit MA1. The second mapping unit MA2 then outputs the fourth and fifth data video signals DS4 and DS5 based on the first and second data video signals DS1 and DS2 and the blue video signal B, . Here, the first data image signal DS1 may be a data image signal for displaying a red image, and the second data image signal DS2 may be a data image signal for displaying a green image.

In one embodiment, when the gray level of the first data video signal DS1 is less than the gray level of the blue video signal B, the second mapping unit MA2 outputs the blue video signal B as the fourth data video Signal DS4.

On the other hand, when the gray level value of the first data video signal DS1 is greater than the gray level value of the blue video signal B, the second mapping unit MA2 outputs the first data video signal DS1 as the fourth data video signal DS1, (DS4). In this case, if the second mapping unit MA2 generates the blue video signal B as the fourth data video signal DS4, the first data video signal DS1 is generated in the first subfield FD1 of the next frame, The liquid crystal molecules may not be sufficiently rearranged. As a result, the luminance of the red image can be reduced. Accordingly, the second mapping unit MA2 generates a signal having a larger gray level value among the first data video signal DS1 and the blue video signal B as the fourth data video signal DS4.

When the gray level of the second data video signal DS2 is lower than the gray level of the blue video signal B, the second mapping unit MA2 outputs the blue video signal B as the fifth data video signal DS5, .

On the other hand, when the gray level value of the second data video signal DS2 is larger than the gray level value of the blue video signal B, the second mapping unit MA2 outputs the second data video signal DS2 as the fifth data video signal (DS5). In this case, if the second mapping unit MA2 generates the blue video signal B as the fifth data video signal DS5, the second data video signal DS2 is generated in the first subfield FD1 of the next frame, The liquid crystal molecules may not be sufficiently rearranged. As a result, the luminance of the green image can be lowered. Accordingly, the second mapping unit MA2 generates a signal having a larger gray level value among the second data video signal DS2 and the blue video signal B as the fifth data video signal DS4.

In another embodiment, the second mapping unit MA2 controls the fourth data video signal DS4 to be generated as the first data video signal DS1. The second mapping unit MA2 compares the gray level value of the second data video signal DS2 with the gray level value of the blue video signal B and then generates the fifth data video signal DS5 according to the comparison result Respectively.

In the above case, when the gray-level values of the first data video signal DS1 and the second data video signal DS2 have a value of 0 respectively, the second mapping unit MA2 outputs the fourth and the 5 data video signals DS4 and DS5.

That is, when the gray level value of the second data video signal DS2 is smaller than the gray level value of the blue video signal B, the second mapping unit MA2 outputs the blue video signal B as the fifth data video signal DS5, . On the other hand, when the gray level value of the second data video signal DS2 is larger than the gray level value of the blue video signal B, the second mapping unit MA2 outputs the second data video signal DS2 as the fifth data video signal (DS5).

In another embodiment, the second mapping unit MA2 sums the gray level value of the first data video signal DS1 and the gray level value of the blue video signal B. The second mapping unit MA2 generates the fourth data video signal DS4 based on half of the summed gray level values. The second mapping unit MA2 sums the gray level value of the second data video signal DS2 and the gray level value of the blue video signal B. [ The second mapping unit MA2 generates the fifth data video signal DS5 based on the intermediate value of the summed gray level values.

Also, the second mapping unit MA2 generates the sixth data video signal DS6 based on only the blue video signal B.

As described above, the second mapping unit MA2 generates the fourth to sixth data video signals DS1 and DS2 based on the first and second data video signals DS1 and DS2 output from the first mapping unit M1. (DS4, DS5, DS6). As a result, during the second subfield FD2, blue reridge is generated in the red pixel RPX and the green pixel GPX, and the overall brightness of the blue image from the display panel 400 can be improved. That is, the overall display quality of the liquid crystal display device 600 can be improved.

8 is a flowchart showing the operation of the timing controller according to the embodiment of the present invention.

Referring to FIG. 8, in step S110, the timing controller 100 (see FIG. 1) receives red, green, and blue video signals R, G,

In step S120, the timing controller 100 generates first to third data video signals DS1, DS2, and DS3 to be output during the first sub-field FD1 based on the red and green video signals R and G, , See Fig. 7).

In step S130, the timing controller 100 compares the gray level values of the first and second data video signals DS1 and DS2 and the blue video signal B, respectively.

In step S140, the timing controller 100 generates the fourth to sixth data video signals (DS4, DS5, DS6, refer to FIG. 7) to be output during the second subfield FD2 according to the comparison result.

The embodiments have been disclosed in the drawings and specification as described above. Although specific terms have been employed herein, they are used for purposes of illustration only and are not intended to limit the scope of the invention as defined in the claims or the claims. Therefore, those skilled in the art will appreciate that various modifications and equivalent embodiments are possible without departing from the scope of the present invention. Accordingly, the true scope of the present invention should be determined by the technical idea of the appended claims.

100: Timing controller
200: Gate driver
300:
400: display panel
500: Backlight unit

Claims (14)

A display panel on which a plurality of pixels are arranged;
A backlight unit for generating first and second lights for each unit frame period and sequentially providing the first and second lights to the pixels; And
And a gamma mapping unit for receiving the red, green, and blue video signals from the outside and generating first and second data signals for controlling the pixels based on the unit frame period,
Wherein the unit frame includes a first sub-frame in which the first light and the first data signals are output, and a second sub-frame in which the second light and the second data signals are output,
Wherein the first data signals are generated based on the red and green image signals during the first sub-frame, and at least one of the second data signals generated during the second sub- And a gray level value of one of the first data signals. The method according to claim 1,
Wherein the first light is yellow light and the second light is blue light. The method according to claim 1,
And a data driver for converting the first and second data signals into data voltages corresponding to the pixels. The method according to claim 1,
Wherein the pixels include first through third pixels,
Wherein the first pixel comprises a first color filter, the second pixel comprises a second color filter, and the third pixel comprises an open portion,
Wherein the first color filter transmits a red image and the second color filter transmits a green image. The method according to claim 1,
Wherein the first data signals include first to third data video signals and the second data signals include fourth to sixth data video signals. 6. The method of claim 5,
Wherein the gamma mapping unit includes a first mapping unit and a second mapping unit,
Wherein the first mapping unit generates the first through third data video signals based on the red video signal and the green video signals. The method according to claim 6,
Wherein the second mapping unit compares the gray level value of the blue video signal and the gray level value of the first or second data video signals and generates the fourth and fifth data video signals according to the comparison result, . 8. The method of claim 7,
Wherein the second mapping unit outputs the fourth data video signal as the blue video signal when the gray level value of the blue video signal is greater than the gray level value of the first data video signal, And outputs the fourth data video signal as the first data video signal when the gradation value is less than the gradation value of the first data video signal. 9. The method of claim 8,
Wherein the first data video signal is a signal for controlling a pixel for displaying a red image among the pixels. 8. The method of claim 7,
Wherein the second mapping unit outputs the fifth data video signal as the blue video signal when the gray level value of the blue video signal is greater than the gray level value of the second data video signal, And outputs the fifth data video signal as the second data video signal when the gradation value of the second data video signal is smaller than the gradation value of the second data video signal. 11. The method of claim 10,
And the second data video signal is a signal for controlling a pixel for displaying a green image among the pixels. 8. The method of claim 7,
Wherein the second mapping unit sums the gray level value of the first data video signal and the gray level value of the blue video signal and outputs the fourth data video signal based on the intermediate value of the summed result. 8. The method of claim 7,
Wherein the second mapping unit sums the gray level value of the second data video signal and the gray level value of the blue video signal and outputs the fifth data video signal based on the intermediate value of the summed result. 6. The method of claim 5,
And the sixth data video signal is output as the blue video signal.

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