KR102470471B1 - Liquid crystal display device and driving method thereof - Google Patents

Abstract

A liquid crystal display device capable of improving image quality while reducing power consumption is provided. The liquid crystal display device includes a data modulator for generating image data by synthesizing first data generated from an image signal and second data generated by modulating data corresponding to a specific horizontal line of a liquid crystal panel among the first data.

Description

Liquid crystal display device and its operating method {Liquid crystal display device and driving method thereof}

The present invention relates to a liquid crystal display device, and in particular, to a liquid crystal display device capable of improving image quality deterioration due to a luminance difference in vertical and horizontal directions while reducing power consumption in an inversion operation of the liquid crystal display device and an operating method thereof. it's about

A liquid crystal display (LCD), which is a representative display device of flat panel display devices, is a device that displays an image using optical anisotropy of liquid crystal, and has advantages such as thin shape, small size, low power consumption, and high image quality.

In general, a liquid crystal display device includes a liquid crystal layer formed between two substrates including a pixel electrode and a common electrode. In such a liquid crystal display, a voltage is applied to two electrodes to form an electric field in a liquid crystal layer, and a desired image is displayed by adjusting the transmittance of light passing through the liquid crystal layer by adjusting the intensity of the electric field formed.

In such a liquid crystal display device, an inversion driving method is used to prevent deterioration and fixation of the liquid crystal when an electric field in one direction is applied to a liquid crystal cell, that is, a pixel for a long time. The inversion driving method refers to inverting the polarity of a data voltage applied to each pixel based on a common voltage in a frame unit, column unit, or dot unit.

1A and 1B are views schematically showing a column inversion driving method in a conventional liquid crystal display, and FIGS. 2A and 2B are views schematically showing a vertical 2-dot inversion driving method in a conventional liquid crystal display.

First, as shown in FIGS. 1A and 1B, in the conventional liquid crystal display device, in an odd frame and an even frame, the polarity of the data voltage supplied to each pixel of the liquid crystal panel is set to the data line. It is operated by a column inversion method that inverts each vertical line and frame corresponding to .

Since there is no potential difference between pixels adjacent to each vertical line in the same frame, the column inversion driving method is characterized in that it consumes less power than other inversion driving methods. However, the conventional column inversion driving method has a problem in that a stripe pattern or flicker occurs between adjacent vertical lines of a liquid crystal panel.

In addition, as shown in FIGS. 2A and 2B, in the conventional liquid crystal display device, in an odd frame and an even frame, the polarity of the data voltage supplied to each pixel of the liquid crystal panel is inverted by 1 dot for pixels adjacent to each other in the horizontal direction. method, and pixels adjacent in the vertical direction are operated by a 2-dot inversion method.

This vertical 2-dot inversion driving method is characterized in that the image quality is excellent compared to other inversion driving methods by canceling flicker generated between pixels adjacent to each other in the vertical and horizontal directions of the liquid crystal panel. However, in the conventional vertical 2-dot inversion driving method, since the polarity of the data voltage must be reversed in the vertical and horizontal directions, the number of variations of the data voltage increases, thereby increasing power consumption of the liquid crystal display.

An object of the present invention is to provide a liquid crystal display capable of improving image quality while reducing power consumption and an operating method thereof.

The liquid crystal display device of the present invention for achieving the above object includes a liquid crystal panel, a data modulating unit and a data driving unit.

The liquid crystal panel is configured by connecting pixels to each of a plurality of horizontal lines.

The data modulator generates first data from the video signal, modulates data corresponding to a specific horizontal line of the liquid crystal panel among the first data according to the coefficient of the polarity control signal to generate second data, and generates second data. Synthesize data to create image data.

The data driver generates data signals according to image data and outputs them to the liquid crystal panel.

A liquid crystal display operating method of the present invention for achieving the above object includes steps of generating image data by generating and synthesizing first data and second data, respectively, and generating a data signal from the image data.

The first data is generated from the image signal to correspond to each of a plurality of horizontal lines of the liquid crystal panel.

The second data is generated by modulating data corresponding to a specific horizontal line of the liquid crystal panel among the first data according to the coefficient of the polarity control signal. 1 data is generated by increasing the gradation level according to the modulation value.

The liquid crystal display device of the present invention can prevent image quality defects such as vertical and horizontal lines caused by a difference in luminance in the vertical and horizontal directions in the liquid crystal panel. In addition, since the liquid crystal display device can reduce the number of inversions of image data in the liquid crystal panel, power consumption of the liquid crystal display device according to the inversion operation can be reduced.

1A and 1B are diagrams schematically illustrating a column inversion driving method in a conventional liquid crystal display.
2A and 2B are diagrams schematically showing a vertical 2-dot inversion driving method in a conventional liquid crystal display.
3 is a diagram showing the configuration of a liquid crystal display device according to the present invention.
FIG. 4 is a diagram showing the configuration of the data modulator shown in FIG. 3 .
5A and 5B are diagrams illustrating an odd frame operation of the liquid crystal display according to the present invention.
6A and 6B are diagrams illustrating an even frame operation of the liquid crystal display according to the present invention.
7 is a graph comparing power consumption between a liquid crystal display according to the present invention and a conventional liquid crystal display.

Hereinafter, a liquid crystal display device and an operating method thereof according to the present invention will be described in detail with reference to the accompanying drawings.

3 is a diagram showing the configuration of a liquid crystal display device according to the present invention.

Referring to FIG. 3 , the liquid crystal display device 100 includes a liquid crystal panel 110 and driving circuits operating the same, for example, a timing controller 140, a gate driver 120, a data driver 130, and a gamma voltage generator ( 160) and the like.

The liquid crystal panel 110 may include a liquid crystal layer (not shown) interposed between an array substrate (not shown) and a color filter substrate (not shown).

A plurality of gate lines GL and a plurality of data lines DL are formed to cross each other on the array substrate of the liquid crystal panel 110 to define a pixel area. A pixel P including a thin film transistor T, a liquid crystal capacitor Clc, and a storage capacitor Cst may be formed in each pixel area.

A black matrix (not shown), a color filter (not shown), and a common electrode (not shown) may be formed on the color filter substrate of the liquid crystal panel 110 . The common electrode may be formed on the array substrate according to the operating method of the liquid crystal panel 110 .

In the liquid crystal panel 110 described above, the thin film transistors T of each pixel P are turned on according to the gate signals applied through the plurality of gate lines GL, and the thin film transistors T turn on. Data signals applied through the plurality of data lines DL are supplied to the pixel electrodes. Subsequently, the liquid crystal capacitor Clc of each pixel P charges a voltage according to the difference between the data signal supplied to the pixel electrode and the common voltage supplied to the common electrode, and adjusts the light transmittance of the liquid crystal layer according to the charged voltage. By adjusting, the liquid crystal panel 110 displays a desired image. The storage capacitor Cst of each pixel P may maintain the voltage charged in the liquid crystal capacitor Clc until the next data signal is supplied.

The timing controller 140 receives control signals input from an external system (not shown), for example, timing signals such as data enable (DE), dot clock (DCLK), vertical synchronization signal (Vsync), and horizontal synchronization signal (Hsync). A control signal for controlling the operation of the gate driving unit 120 and the data driving unit 130 may be generated by using the control signal. Control signals generated by the timing controller 140 include a gate control signal GCS and a data control signal DCS.

The gate control signal GCS includes a gate start pulse, a gate shift clock, a gate output enable, and the like. The data control signal DCS includes a source start pulse, a source sampling clock, a source output enable, and a polarity control signal POL. Here, the polarity control signal POL is a control signal that causes the liquid crystal panel 110 to operate in a vertical N-dot inversion method, and in this case, the coefficient N may be a natural number equal to or greater than 4.

In addition, the timing controller 140 may include a data modulator 150 that modulates the image signal RGB input from an external system to generate image data Vdata. The data modulator 150 is connected to a specific horizontal line, for example, a pixel P connected to some of the plurality of gate lines GL, in each frame of the liquid crystal panel 110, for example, an odd frame and an even frame. The image data Vdata may be generated by modulating the corresponding image signal RGB to increase or decrease the gradation level. The data modulator 150 determines the frame and horizontal line of the liquid crystal panel 110 on which the image signal RGB is to be displayed, and refers to the determination result to determine the gradation of the image signal RGB corresponding to a specific horizontal line in each frame. You can modulate the level. The configuration of the data modulator 150 will be described later in detail.

The gate driver 120 may generate a gate signal according to the gate control signal GCS output from the timing controller 140 . Gate signals may be sequentially output to the plurality of gate lines GL of the liquid crystal panel 110 . The gate driver 120 is composed of a COF (Chip On Film) form and attached to one side of the liquid crystal panel 110, or is composed of a Gate In Panel (GIP) form and is attached to one side of the liquid crystal panel 110. Can be built inside.

The data driver 130 may sample and latch the image data Vdata output from the data modulator 150 according to the data control signal DCS output from the timing controller 140 and convert the data into parallel data. The data driver 130 may generate a data signal from the converted parallel data using a plurality of gamma voltages Vgma provided from the gamma voltage generator 160 . Data signals may be output through the plurality of data lines DL when the plurality of gate lines GL are enabled by the gate signal.

The plurality of gamma voltages Vgma output from the gamma voltage generator 160 may include a positive polarity gamma voltage and a negative polarity gamma voltage. Data signals generated by the data driver 130 according to the plurality of gamma voltages Vgma have positive and negative polarities based on the common voltage Vcom. Accordingly, the data driver 130 may alternately output a positive polarity data signal and a negative polarity data signal according to the polarity control signal POL of the data control signal DCS.

FIG. 4 is a diagram showing the configuration of the data modulator shown in FIG. 3 .

Referring to FIGS. 3 and 4 , the data modulator 150 may include a determiner 170 and a modulator 180 .

The determination unit 170 may generate and output frame information FI and horizontal line information LI for the image signal RGB. The determination unit 170 may generate frame information FI of the liquid crystal panel 110 on which the image signal RGB is to be displayed, that is, odd frame information and even frame information. In addition, the determination unit 170 provides pixel information of the liquid crystal panel 110 on which the image signal RGB is to be displayed, for example, horizontal line information (for example, horizontal line information of pixels connected to the gate line GL) of the liquid crystal panel 110. LI) can be created. The horizontal line information LI may include odd horizontal line information and even horizontal line information.

The modulator 180 refers to the frame information FI and the horizontal line information LI output from the determination unit 170 and converts the image data Vdata from the image signal RGB according to the polarity control signal POL. can create The modulator 180 may include a first modulator 181 , a second modulator 183 and a video synthesizer 185 .

The first modulator 181 receives image data corresponding to each of the pixels P connected to a plurality of horizontal lines, that is, a plurality of gate lines GL, in each frame of the liquid crystal panel 110 from the image signal RGB, e.g. First data data1 may be generated. The first data data1 is image data generated without modulation of the image signal RGB.

The second modulator 183 may generate image data obtained by modulating the gray level of the first data data1 according to the polarity control signal POL, for example, second data data2. The second modulator 183 refers to the frame information FI and the horizontal line information LI output from the determination unit 170, and generates the first modulator 181 according to the polarity control signal POL. Among the first data (data1), the grayscale level of data corresponding to a pixel (P) connected to a specific horizontal line of the liquid crystal panel 110, that is, a specific gate line (GL) among the plurality of gate lines (GL) is modulated to obtain 2 data (data2) can be created. The second modulator 183 may generate second data data2 through level modulation that increases or decreases the gradation level of the first data data1 according to a predetermined modulation value.

Here, the second modulator 183 may modulate the grayscale level of the first data data1 corresponding to a specific horizontal line according to the coefficient size of the polarity control signal POL.

For example, in an odd frame of the liquid crystal panel 110 according to the frame information FI, the second modulator 183 outputs a polarity control signal ( The second data data2 may be generated by modulating the gradation level of the first data data1 corresponding to the odd horizontal line that is less than or equal to the coefficient of POL. Next, in the same frame, that is, in an odd frame, the second modulator 183 converts the polarity control signal POL among a plurality of horizontal lines of the liquid crystal panel 110 according to the horizontal line information LI of the liquid crystal panel 110. The second data data2 may be generated by modulating the gradation level of the first data data1 corresponding to the even horizontal line greater than the coefficient.

In addition, in an even frame of the liquid crystal panel 110 according to the frame information FI, the second modulator 183 outputs a polarity control signal ( The second data data2 may be generated by modulating the gradation level of the first data data1 corresponding to the even horizontal line smaller than or equal to the coefficient of POL. Subsequently, in the same frame, the second modulator 183 outputs a number corresponding to an odd horizontal line greater than a coefficient of the polarity control signal POL among a plurality of horizontal lines of the liquid crystal panel 110 according to the horizontal line information LI. Second data data2 may be generated by modulating the gray level of the first data data1.

As such, the second modulator 183 modulates the first data data1 corresponding to a specific horizontal line in each of the odd and even frames of the liquid crystal panel 110 according to the polarity control signal POL to obtain second data. (data2) can be created.

At this time, the second modulator 183 changes the horizontal line where the second data data2 is generated based on the coefficient of the polarity control signal POL in one frame operation of the liquid crystal panel 110, thereby operating the same frame. Horizontal lines corresponding to the first data (data1) and horizontal lines corresponding to the second data (data2) are repeated within the screen, thereby preventing a horizontal line defect from occurring.

The video synthesis unit 185 synthesizes the first data data1 generated by the first modulator 181 and the second data data2 generated by the second modulator 183 to generate video data Vdata. can do. The image synthesis unit 185 may generate image data Vdata by alternately synthesizing first data data1 and second data data2 to correspond to each of a plurality of horizontal lines of the liquid crystal panel 110 . Such image data Vdata may be output to the data driver 130 during one frame operation of the liquid crystal panel 110 .

As described above, the data modulator 150 adjusts the gradation of the first data data1 corresponding to a specific horizontal line in each of the odd and even frames of the liquid crystal panel 110 according to the coefficient size of the polarity control signal POL. The second data data2 may be generated by modulating the level. Next, the first data data1 and the second data data2 are synthesized to generate and output image data Vdata. Here, the first data (data1) may be image data generated from the image signal (RGB), and the second data (data2) may be image data modulated to increase or decrease some of the gradation levels of the first data (data1). have.

According to the data modulator 150, the liquid crystal display device 100 of the present embodiment can reduce power consumption according to the inversion operation of the liquid crystal panel 110 compared to conventional liquid crystal display devices, and can be used in a vertical or horizontal direction. As a result, it is possible to improve the occurrence of quality defects such as vertical lines or horizontal lines.

Hereinafter, the operation of the above-described data modulator 150 will be described in detail with reference to the drawings.

5A and 5B are views showing an odd frame operation of the liquid crystal display according to the present invention, and FIGS. 6A and 6B are views showing an even frame operation of the liquid crystal display according to the present invention.

For convenience of explanation, the liquid crystal panel 110 of this embodiment has 48 R, G, and B pixels P connected to eight horizontal lines HL1 to HL8 and six vertical lines VL1 to VL6, respectively. Let's take an example of what happened. In addition, the polarity control signal (POL) of the data control signal (DCS) generated by the timing controller 140 is a control signal for operating the liquid crystal panel 110 in a vertical N (N is a natural number of 4 or more) dot inversion method, At this time, it is assumed that the coefficient N is 4 as an example.

Accordingly, the liquid crystal panel 110 shown in FIGS. 5A and 6A has a polarity in which the plurality of pixels P are inverted every 4 dots in the vertical direction according to the polarity control signal POL of the vertical 4-dot inversion method. . That is, each of the R, G, and B pixels P connected to the first to fourth horizontal lines HL1 to HL4 of the liquid crystal panel 110 are connected to the fifth to eighth horizontal lines HL5 to HL8 on the same vertical line. It has a polarity opposite to that of the connected R, G, and B pixels (P).

For example, as shown in FIG. 5A , among the R pixels R corresponding to the first vertical line VL1 of the liquid crystal panel 110, the R pixels R connected to the first to fourth horizontal lines HL1 to HL4 ) has a (+) polarity, and R pixels R connected to the fifth to eighth horizontal lines HL5 to HL8 have a (-) polarity. In addition, as shown in FIG. 6A , among the R pixels R corresponding to the first vertical line VL1 of the liquid crystal panel 110, the R pixels R connected to the first to fourth horizontal lines HL1 to HL4 ) has a (−) polarity, and R pixels R connected to the fifth to eighth horizontal lines HL5 to HL8 have a (+) polarity.

Referring to FIGS. 4 and 5A , the determination unit 170 of the data modulator 150 may generate frame information FI and horizontal line information LI of the liquid crystal panel 110 . Here, the frame information (FI) is odd frame information. In addition, the horizontal line information (LI) is information on odd numbered horizontal lines for the first, third, fifth, and seventh horizontal lines (HL1, HL3, HL5, and HL7) of the liquid crystal panel 110 and the second, second, and third horizontal line information of the liquid crystal panel 110. It includes excellent horizontal line information for 4, 6, and 8 horizontal lines (HL2, HL4, HL6, and HL8).

The first modulator 181 of the data modulator 150 generates first data data1 corresponding to each of the plurality of horizontal lines HL1 to HL8 of the liquid crystal panel 110 from the video signal RGB input from the outside. can create The first data data1 has a polarity that is reversed every 4 dots in the vertical direction in each vertical line VL1 to VL6 of the liquid crystal panel 110 according to the polarity control signal POL.

The second modulator 183 of the data modulator 150 refers to the frame information FI and the horizontal line information LI and generates the first modulator 181 according to the coefficient of the polarity control signal POL. Second data data2 may be generated by modulating the gradation level of the first data data1 corresponding to a specific horizontal line among the first data data1. Here, the second modulator 183 maintains the polarity of the first data data1 as it is.

Here, the frame information FI is odd frame information, and the coefficient of the polarity control signal POL is 4. Accordingly, the second modulator 183 outputs odd horizontal lines that are smaller than or equal to the coefficient of the polarity control signal POL among the plurality of horizontal lines HL1 to HL8 of the liquid crystal panel 110, that is, the first and third horizontal lines. Second data data2 may be generated by modulating the first data data1 corresponding to (HL1, HL3), respectively. In addition, the second modulator 183 is an even horizontal line greater than the coefficient of the polarity control signal POL among the plurality of horizontal lines HL1 to HL8 of the liquid crystal panel 110, that is, the sixth and eighth horizontal lines HL6. , HL8), the second data data2 may be generated by modulating the first data data1 corresponding to each.

At this time, the second modulator 183 generates first data having a (+) polarity among first data data1 corresponding to the first, third, sixth, and eighth horizontal lines HL1, HL3, HL6, and HL8, respectively. The gradation level of (data1) is decreased by the modulation value (α), and the gradation level of the first data (data1) having (-) polarity is increased by the modulation value (α) to generate second data (data2) can do. Here, the modulation value α is a gradation level, and may be approximately 1 to 3 gradations.

The image synthesizer 185 of the data modulator 150 synthesizes the first data data1 generated by the first modulator 181 and the second data data2 generated by the second modulator 183, Image data (Vdata) may be generated. The image data Vdata may be output to the data driver 130 during an odd frame operation of the liquid crystal panel 110 . The image data Vdata is generated when each of the plurality of horizontal lines HL1 to HL8 is enabled by the gate signal output from the gate driver 120, that is, each vertical line ( Each VL1 to VL6) can be output as a data signal.

The image data Vdata includes first data data1 generated from the image signal RGB and second data data2 obtained by modulating the gray level of the first data data1. Accordingly, even though the image signal RGB has the same gradation level for the plurality of horizontal lines HL1 to HL8 of the liquid crystal panel 110, the image data Vdata is different for the plurality of horizontal lines HL1 to HL8. It can have different gradation levels.

As shown in FIG. 5B, image data Vdata applied to a plurality of R pixels R corresponding to one vertical line, that is, a first vertical line VL1, through a plurality of horizontal lines HL1 to HL8 has different gradation levels for each horizontal line.

That is, the second data data2 of the image data Vdata corresponding to the first and third horizontal lines HL1 and HL3 of the liquid crystal panel 110 corresponds to the second and fourth horizontal lines HL2 and HL4. Compared to the first data (data1) of the image data (Vdata) to be, the grayscale level is reduced by the modulation value (α). In addition, the second data data2 of the image data Vdata corresponding to the sixth and eighth horizontal lines HL6 and HL8 of the liquid crystal panel 110 corresponds to the fifth and seventh horizontal lines HL5 and HL7 Compared to the first data (data1) of the image data (Vdata) to be, the gradation level is increased by the modulation value (α).

In this way, the data modulator 150 generates image data Vdata that makes the gradation levels of adjacent horizontal lines different from each other in odd frame operation of the liquid crystal panel 110 according to the coefficient of the polarity control signal POL. can At this time, the polarity control signal POL is a signal that causes the liquid crystal panel 110 to perform vertical N (N is a natural number equal to or greater than 4) dot inversion operation.

Therefore, the liquid crystal display device 100 of this embodiment can prevent the occurrence of quality defects such as vertical lines or horizontal lines caused by a difference in luminance in the vertical and horizontal directions in the liquid crystal panel 110 compared to conventional liquid crystal display devices. . In addition, the liquid crystal display device 100 of this embodiment can reduce the amount of change in the image data Vdata, that is, the number of times of inversion, in the liquid crystal panel 110, compared to the conventional liquid crystal display device operated in a vertical 2-dot inversion method. Accordingly, as shown in FIG. 7 , the power consumption (B) of the liquid crystal display device 100 of the present invention can be reduced compared to the power consumption (A) of the conventional liquid crystal display device.

Referring to FIGS. 4 and 6A , the determination unit 170 of the data modulator 150 may generate frame information FI and horizontal line information LI of the liquid crystal panel 110 . Here, the frame information (FI) is even frame information. In addition, the horizontal line information (LI) is information on odd numbered horizontal lines for the first, third, fifth, and seventh horizontal lines (HL1, HL3, HL5, and HL7) of the liquid crystal panel 110 and the second, second, and third horizontal line information of the liquid crystal panel 110. It includes excellent horizontal line information for 4, 6, and 8 horizontal lines (HL2, HL4, HL6, and HL8).

The first modulator 181 of the data modulator 150 generates first data data1 corresponding to each of the plurality of horizontal lines HL1 to HL8 of the liquid crystal panel 110 from the video signal RGB input from the outside. can create The first data data1 has a polarity that is reversed every 4 dots in the vertical direction in each vertical line VL1 to VL6 of the liquid crystal panel 110 according to the polarity control signal POL.

The second modulator 183 of the data modulator 150 refers to the frame information FI and the horizontal line information LI and generates the first modulator 181 according to the coefficient of the polarity control signal POL. Second data data2 may be generated by modulating the gradation level of the first data data1 corresponding to a specific horizontal line among the first data data1. Here, the second modulator 183 maintains the polarity of the first data data1 as it is.

Here, the frame information FI is even frame information, and the coefficient of the polarity control signal POL is 4. Accordingly, the second modulator 183 outputs even horizontal lines that are smaller than or equal to the coefficient of the polarity control signal POL among the plurality of horizontal lines HL1 to HL8 of the liquid crystal panel 110, that is, the second and fourth horizontal lines. Second data data2 may be generated by modulating the first data data1 corresponding to (HL2, HL4), respectively. In addition, the second modulator 183 is an odd horizontal line greater than the coefficient of the polarity control signal POL among the plurality of horizontal lines HL1 to HL8 of the liquid crystal panel 110, that is, the fifth and seventh horizontal lines HL5. , HL7), the second data data2 may be generated by modulating the first data data1 corresponding to each.

At this time, the second modulator 183 outputs first data having a (+) polarity among first data data1 corresponding to the second, fourth, fifth, and seventh horizontal lines HL2, HL4, HL5, and HL7, respectively. The gradation level of (data1) is reduced by the modulation value (α), and the gradation level of the first data (data1) having (-) polarity is increased by the modulation value (α) to generate second data (data2) can do. Here, the modulation value α is a gradation level, and may be approximately 1 to 3 gradations.

The image synthesizer 185 of the data modulator 150 synthesizes the first data data1 generated by the first modulator 181 and the second data data2 generated by the second modulator 183, Image data (Vdata) may be generated. The image data Vdata may be output to the data driver 130 during even frame operation of the liquid crystal panel 110 . The image data Vdata may be output as a data signal for each vertical line VL1 to VL6 by the data driver during one horizontal period (1H) of the liquid crystal panel 110 .

Meanwhile, as described above, since the image data Vdata includes the first data data1 generated from the image signal RGB and the second data data2 obtained by modulating the gray level of the first data data1, Even if the image signals RGB have the same gradation level, the image data Vdata may have different gradation levels for the plurality of horizontal lines HL1 to HL8 of the liquid crystal panel 110 .

As shown in FIG. 6B, image data Vdata applied to a plurality of R pixels R corresponding to one vertical line, that is, the first vertical line VL1, through a plurality of horizontal lines HL1 to HL8 has different gradation levels for each horizontal line.

That is, the second data data2 of the image data Vdata corresponding to the second and fourth horizontal lines HL2 and HL4 of the liquid crystal panel 110 corresponds to the first and third horizontal lines HL1 and HL3 Compared to the first data (data1) of the image data (Vdata) to be, the gradation level is increased by the modulation value (α). In addition, the second data data2 of the image data Vdata corresponding to the fifth and seventh horizontal lines HL5 and HL7 of the liquid crystal panel 110 corresponds to the sixth and eighth horizontal lines HL6 and HL8 Compared to the first data (data1) of the image data (Vdata) to be, the grayscale level is reduced by the modulation value (α).

In this way, the data modulator 150 generates image data Vdata that makes the gradation levels of adjacent horizontal lines different from each other in even frame operation of the liquid crystal panel 110 according to the coefficient of the polarity control signal POL. can

Therefore, the liquid crystal display device 100 of this embodiment can prevent the occurrence of quality defects such as vertical lines or horizontal lines caused by a difference in luminance in the vertical and horizontal directions in the liquid crystal panel 110 compared to conventional liquid crystal display devices. . In addition, the liquid crystal display device 100 of this embodiment can reduce the amount of change in the image data Vdata, that is, the number of times of inversion, in the liquid crystal panel 110, compared to the conventional liquid crystal display device operated in a vertical 2-dot inversion method. Accordingly, as shown in FIG. 7 , the power consumption (B) of the liquid crystal display device 100 of the present invention can be reduced compared to the power consumption (A) of the conventional liquid crystal display device.

Although many details have been specifically described in the foregoing description, this should be interpreted as an example of a preferred embodiment rather than limiting the scope of the invention. Therefore, the invention should not be defined according to the described examples, but should be defined according to the scope of the claims and the scope of the claims.

100: liquid crystal display device 110: liquid crystal panel
120: gate driving unit 130: data driving unit
140: timing control unit 150: data modulator
160: gamma voltage generating unit 170: determining unit
180: modulator 181: first modulator
183: second modulation unit 185: video synthesis unit

Claims (13)

a liquid crystal panel having a plurality of pixels connected to a plurality of horizontal lines;
First data generated from an externally provided video signal and second data obtained by modulating the first data corresponding to a pixel connected to a specific horizontal line of the liquid crystal panel among the first data according to a polarity control signal are synthesized to obtain image data. a data modulator that generates; and
A data driver generating a data signal according to the image data and outputting the data signal to the liquid crystal panel;
The second data,
In an odd frame of the liquid crystal panel, the gradation level of the first data corresponding to an odd horizontal line smaller than or equal to the coefficient of the polarity control signal and the first data corresponding to an even horizontal line greater than the coefficient of the polarity control signal. It is created by modulating
In an even frame of the liquid crystal panel, the first data corresponding to an even horizontal line equal to or smaller than the coefficient of the polarity control signal and the gradation level of the first data corresponding to an odd horizontal line greater than the coefficient of the polarity control signal A liquid crystal display device created by modulating According to claim 1,
The second data,
Among the first data corresponding to the specific horizontal line, the gradation level of the first data of positive polarity is reduced by the modulation value, and the gradation level of the first data of negative polarity is increased by the modulation value. According to claim 2,
The modulation value is a liquid crystal display device of 1 to 3 gray scales. According to claim 1,
The data modulator,
a first modulator generating the first data corresponding to each of the plurality of horizontal lines from the video signal;
a second modulator for generating the second data by modulating the gradation level of the first data corresponding to the specific horizontal line according to the coefficient of the polarity control signal; and
and a video synthesis unit configured to synthesize the first data and the second data and output the synthesized image data. delete delete According to claim 4,
The coefficient of the polarity control signal is a natural number of 4 or more. generating first data corresponding to each of a plurality of horizontal lines of the liquid crystal panel from an image signal provided from the outside;
According to the coefficient of the polarity control signal, the gradation level of the first data of positive polarity among the first data corresponding to the specific horizontal line of the liquid crystal panel is modulated so as to be reduced by the modulation value, and the gradation level of the first data of negative polarity is modulated by the modulation value. generating second data by modulating so as to increase by the value;
synthesizing the first data and the second data to generate image data; and
generating a data signal from the image data and outputting the data signal to the liquid crystal panel;
The second data,
In an odd frame of the liquid crystal panel, the gradation level of the first data corresponding to an odd horizontal line smaller than or equal to the coefficient of the polarity control signal and the first data corresponding to an even horizontal line greater than the coefficient of the polarity control signal. It is created by modulating
In an even frame of the liquid crystal panel, the first data corresponding to an even horizontal line equal to or smaller than the coefficient of the polarity control signal and the gradation level of the first data corresponding to an odd horizontal line greater than the coefficient of the polarity control signal A method of operating a liquid crystal display device generated by modulating a. According to claim 8,
The modulation value is a method of operating a liquid crystal display device of 1 to 3 gray scales. delete delete According to claim 8,
The coefficient of the polarity control signal is a natural number of 4 or more.
According to claim 1,
The liquid crystal panel includes first to eighth horizontal lines and operates in a vertical 4-dot inversion method,
The second data may include the first data corresponding to the first, third, sixth, and eighth horizontal lines in the odd frame and the second, fourth, fifth, and seventh in the even frame. Among the first data corresponding to the horizontal line, the gradation level of the first data of positive polarity is modulated to decrease by the modulation value, and the gradation level of the first data of negative polarity is modulated to increase by the modulation value. liquid crystal display.

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