KR20130020308A

KR20130020308A - Method of driving liquid crystal panel

Info

Publication number: KR20130020308A
Application number: KR1020110082863A
Authority: KR
Inventors: 김정현
Original assignee: 엘지디스플레이 주식회사
Priority date: 2011-08-19
Filing date: 2011-08-19
Publication date: 2013-02-27

Abstract

PURPOSE: A method for driving a liquid crystal panel is provided to prevent the distortion of an image by driving a sub pixel group with a dot inversion and an adjacent sub pixel group with a different polarity. CONSTITUTION: A liquid crystal panel includes a first sub pixel group(171). The first sub pixel group includes the preset number of sub pixels. The first sub pixel group includes a second sub pixel group(173) and a third sub pixel group(175). The second and third sub pixel groups include the same number of sub pixels. The second sub pixel group and the third sub pixel group receive the inverted polarity.

Description

Method of driving liquid crystal panel

The embodiment relates to a method of driving a liquid crystal panel.

Various display apparatuses for displaying information have been developed. The display device is, for example, a liquid crystal display device, a plasma display panel device, an electrophoretic display device, an organic electro-luminescence display device and a semiconductor. And a semi-conductor light-emitting display device. Among them, the liquid crystal display device has the advantages of light and small, high brightness, full color, and large size, and thus has been in the spotlight in the mainstream of the display device.

The liquid crystal display device displays an image on the liquid crystal panel by adjusting the light transmittance of the liquid crystal cell on the liquid crystal panel according to the grayscale value of the data. When a direct current voltage is applied to a liquid crystal cell arranged in the liquid crystal panel for a long time, the light transmission characteristic of the liquid crystal cell is degraded. This DC fixation causes the afterimage to appear on the image displayed on the liquid crystal panel, which acts as a cause of deterioration of the image quality.

In order to prevent the DC fixation, an inversion liquid crystal display device in which the pixel data signal to be supplied to the liquid crystal cells of the liquid crystal panel is inverted based on a common voltage has been proposed.

1 is a view showing an image of a liquid crystal panel driven in a dot-inversion or horizontal 2-dot inversion method to display a specific image.

1A is a diagram showing an image of a liquid crystal panel driven by a dot inversion method to display a specific image.

FIG. 1B is a view showing an image of a liquid crystal panel driven in a horizontal two-dot inversion manner to display a specific image.

1 shows a specific image displayed in one frame. Referring to FIG. 1, the liquid crystal panel includes a plurality of pixels. The pixel includes three subpixels consisting of R, G, and B.

The dot inversion scheme is a driving scheme in which polarities between adjacent subpixels are changed based on a common voltage in one frame.

In the horizontal 2-dot inversion, two horizontally adjacent subpixels are driven with the same polarity, and two subpixels adjacent to the same polarity subpixels are driven with opposite polarities. In other words, the driving method is to drive two sub-pixels with the same polarity and drive them in the same manner as the dot inversion.

The specific pattern for displaying a gray image is displayed on the liquid crystal panel of FIG. 1A. When the liquid crystal panel is in the normally white mode, a data voltage is applied to the subpixels displayed in black. When the specific pattern is applied, the common voltage applied to the common lines arranged in the row direction may move in one polarity direction to distort the luminance of the corresponding subpixel or the adjacent subpixel.

For example, looking at the first row driven by the same common line, voltage is applied only to odd-numbered pixels PX1, PX3, PX5, and PX7, positive polarity is applied to R and B subpixels, and negative to G subpixels. Polarity is applied. As a result, the positive polarity prevails in the first common line, so that the common voltage may move in the positive polarity direction, thereby distorting the image.

The specific pattern for displaying a gray image is displayed on the liquid crystal panel of FIG. 1B. When the specific pattern is applied, the luminance of the corresponding subpixel or the adjacent subpixel may be distorted.

For example, if you examine the first row driven by the same common line, only the third, fourth, seventh and eighth pixels (PX3, PX4, PX7, PX8) are energized and the third pixel (PX3) In this case, the negative polarity is applied to the R and G subpixels, and the positive polarity is applied to the B subpixel, and in the case of the fourth pixel PX4, the negative polarity is applied to the G and B subpixels, and the positive polarity is applied to the R subpixel. In the case of (PX7), the negative polarity is applied to the R and G subpixels, and the positive polarity is applied to the B subpixel, and in the eighth pixel (PX8), the negative polarity is applied to the G and B subpixels, and the positive polarity is applied to the R subpixel. . As a result, the negative polarity prevails in the first common line, so that the common voltage may move in the negative polarity direction, thereby distorting the image.

The image may be distorted due to the movement of the common voltage, resulting in a color difference, and the image quality may be degraded.

The embodiment provides a method of driving a liquid crystal panel to prevent distortion of an image.

The embodiment provides a method of driving a liquid crystal panel for improving image quality.

A driving method of a liquid crystal panel according to an embodiment includes a liquid crystal panel in which a first subpixel group including a predetermined number of subpixels adjacent to a plurality of subpixels in a row direction is repeated, and the first subpixel group Includes a second subpixel group and a third subpixel group, the second subpixel group and the third subpixel group include the same number of subpixels, and the second subpixel group and the third subpixel group The inverted polarity is applied to the pixel group.

According to an embodiment, a subpixel group including a plurality of subpixels is driven with a dot in version, and a subpixel group adjacent to the subpixel group is driven with different polarities to prevent distortion of an image.

The embodiment improves the image quality by driving a subpixel group including a plurality of subpixels in a dot-in version and driving a subpixel group adjacent to the subpixel group with different polarities.

1 is a view showing an image of a liquid crystal panel driven in a dot-inversion or horizontal 2-dot inversion method to display a specific image.
2 is a diagram illustrating a liquid crystal display according to an exemplary embodiment.
3 is a view illustrating an image of a liquid crystal panel driven by an inversion method according to a first embodiment.
4 is a view showing an image of a liquid crystal panel driven in an inversion method according to a second embodiment.

2 is a diagram illustrating a liquid crystal display according to an exemplary embodiment.

Referring to FIG. 2, a liquid crystal display device includes a timing controller 10 on a substrate 1. The gate driver 20, the data driver 30, and the common voltage generator 40 may be included.

The timing controller 10 may receive a data clock signal Dclk, a vertical synchronization signal Vsync, a horizontal synchronization signal Hsync, and the like together with a data signal from an external graphics card.

The timing controller 10 is a timing control signal for controlling the gate driver 20 and the data driver 30 based on a data clock signal Dclk, a vertical synchronization signal Vsync, and a horizontal synchronization signal Hsync. Can be generated. The timing control signal may include a gate control signal and a data control signal.

The gate control signal may include, for example, a gate start pulse (GSP), a gate shift clock (GSC), and a gate output enable (GOE). The gate start pulse GSP is a signal for controlling the driving start time of the first gate line of the liquid crystal panel in one frame, and the gate shift clock GSC is a signal for controlling the start timing of each gate driving of the liquid crystal panel. The gate output enable (GOE) is a signal that controls the time point at which the gate signal is sent to each gate line.

The data control signal may include a source start pulse (SSP), a source shift clock (SSC), a source output enable (SOE) signal, a polarity signal (POL) . The source start pulse SSP is a signal that controls the supply time of the data voltage of the first line in one frame, and the source shift clock SSC is a signal that controls the supply time of the data voltage of each line. The source output enable SOE is a signal for controlling a time point at which a data voltage is sent to the data lines 31 of the liquid crystal panel, and the polarity signal POL is a signal for selecting a data voltage or a negative data voltage. to be.

The timing controller 10 may rearrange the data signals provided from the graphics card to the data driver 30.

The timing controller 10 may provide the gate control signal to the gate driver 20, and provide the data control signal and the data signal to the data driver 30.

The gate driver 20 may sequentially generate a gate signal based on the gate control signal provided from the timing controller 10 and provide the gate signal to the gate line 21.

The gate line 21 is electrically connected to the gate driver 20 and is formed along the first direction. The data line 31 is electrically connected to the data driver 30 and is formed along a second direction crossing the gate line 21.

The common voltage generator 40 may be formed in an area opposite the gate driver 20. The common voltage generator 40 may provide a common voltage to the common line 41. The common voltage may be a DC voltage.

The common line 41 may be formed along a first direction parallel to the gate line 21.

The subpixel 50 is defined by the intersection of the gate line 21 and the data line 31. The subpixel 50 may include a thin film transistor 51 electrically connected to the gate line 21 and the data line 31. A drain electrode (not shown) of the thin film transistor 53 is electrically connected to a pixel electrode (not shown), and a liquid crystal cell 53 is formed between the pixel electrode (not shown) and the common line 41.

A parasitic capacitor 55 may be formed between the data line 55 and the common line 41.

Ripple may occur in the common voltage applied to the common line 41 due to the influence of the liquid crystal cell 53 and the parasitic capacitor 55, and the voltage applied to the data lines 31 may be shifted with one polarity. In this case, distortion may occur in the common voltage.

3 is a view illustrating an image of a liquid crystal panel driven by an inversion method according to a first embodiment.

3 shows a specific image displayed in one frame. Referring to FIG. 3A, the liquid crystal panel includes a plurality of pixels. The pixel includes three subpixels consisting of R, G, and B.

In the inversion scheme according to the first exemplary embodiment, the first subpixel group 71 is repeatedly arranged. The first subpixel group 71 may include a second subpixel group 73 and a third subpixel group 75.

The second subpixel group 73 may include four subpixels. The second subpixel group 73 may include an R subpixel of the first pixel PX1 and the second pixel PX2. The second subpixel group 73 is driven in the same manner as dot inversion in the second subpixel group 73. In other words, the polarity is changed between adjacent subpixels in the second subpixel group 73. Looking at the first row driven by the same common line, the R and B subpixels of the first pixel PX1 are applied with positive polarity, and the G subpixel and the second pixel PX2 of the first pixel PX1 are applied. The R subpixel of may be applied with negative polarity.

The third subpixel group 75 may include four subpixels. The third subpixel group 75 may be located adjacent to the second subpixel group 73. The third subpixel group 75 may include G and B subpixels of the second pixel PX2 and R and G subpixels of the third pixel PX3. The third subpixel group 75 is driven in the same manner as the dot inversion scheme in the third subpixel group 75. In other words, polarities between adjacent subpixels in the third subpixel group 75 are changed. Examining the first row driven by the same common line, a positive polarity is applied to the B subpixel of the second pixel PX2 and the G subpixel of the third pixel PX3, and the second pixel PX2 Negative polarity may be applied to the G subpixel and the R subpixel of the third pixel PX3. That is, the third subpixel group 75 is driven by inverting the second subpixel group 73.

Polarities of the second subpixel group 73 and the third subpixel group 75 may be applied in a symmetrical form to the second subpixel group 73 and the third subpixel group 75. .

As a result, the first subpixel group 71 may include eight subpixels.

The specific pattern for displaying a gray image is displayed on the liquid crystal panel of FIG. 3A. The image displayed on the liquid crystal panel of FIG. 3A is the same image as the image displayed on the liquid crystal panel of FIG. 1A. When the liquid crystal panel is in the normally white mode, a data voltage is applied to the subpixels displayed in black. When the specific pattern is applied, the polarity of the common voltage applied to the common lines arranged in the row direction is not distorted unlike in FIG. 1A.

For example, considering the first row driven by the same common line, the voltage is applied only to the odd pixels PX1, PX3, PX5, and PX7. Examining the subpixels, the first pixel PX1 has a positive polarity applied to the R and B subpixels, and the negative polarity is applied to the G subpixel, and the third pixel PX3 has a positive polarity, R Negative polarity is applied to the subpixel, positive polarity is applied to the G subpixel for the fifth pixel PX5, and negative polarity is applied to the R and B subpixels for the fifth pixel PX5, and positive polarity is applied to the R subpixel for the seventh pixel PX7. The negative polarity is applied to the G, B subpixels. As a result, the number of subpixels to which positive polarity is applied is the same as the number of subpixels to which negative polarity is applied, so that the image is displayed without distortion of the common voltage to positive or negative polarity, thereby improving display quality and no color difference. .

The specific pattern for displaying a gray image is displayed on the liquid crystal panel of FIG. 3B. The image displayed on the liquid crystal panel of FIG. 3B is the same image as the image displayed on the liquid crystal panel of FIG. 1B. When the specific pattern is applied, the polarity of the common voltage applied to the common lines arranged in the row direction is not distorted unlike in FIG. 1B.

For example, looking at the first row driven by the same common line, voltage is applied only to the third, fourth, seventh and eighth pixels PX3, PX4, PX7, and PX8. In the third pixel PX3, positive polarity is applied to the G and B subpixels, and negative polarity is applied to the R subpixel, and in the fourth pixel PX4, positive polarity is applied to the G subpixel, and negative polarity is applied to the R and B subpixels. Is applied to the R subpixel in the case of the seventh pixel PX7, and negative is applied to the G and B subpixels, and is positive to the R and B subpixels in the eighth pixel PX8. Negative polarity is applied to. As a result, the number of subpixels to which positive polarity is applied is the same as the number of subpixels to which negative polarity is applied, so that the image is displayed without distortion of the common voltage to positive or negative polarity, thereby improving display quality and no color difference. .

In the liquid crystal panel of FIG. 3C, a specific pattern for displaying a yellow image is displayed. In the image applied to the liquid crystal panel of FIG. 3C, the R and G subpixels of each pixel transmit light, and the B subpixel does not transmit light, thereby displaying a yellow image by combining red and green light. When the specific pattern is applied, the common voltage may partially shift to distort the luminance.

For example, looking at the first row driven by the same common line, the voltage is applied only to the B sub-pixels for every pixel. Positive polarity is applied to the B subpixels of the first, second, third and eighth pixels (PX1, PX2, PX3, PX8) and the fourth, fifth, sixth, and seventh pixels (PX4, PX5, PX6, Negative polarity is applied to the B subpixel of PX7). The number of subpixels to which positive polarity is applied is the same as the number of subpixels to which negative polarity is applied, but negative polarity is applied to B subpixels of the fourth, fifth, sixth, and seventh pixels PX4, PX5, PX6, and PX7. The negative polarity is partially repeated, so that the common voltage moves in the negative direction in the region corresponding to the fourth, fifth, sixth, and seventh pixels (PX4, PX5, PX6, and PX7), thereby partially displaying the image. Can be distorted.

4 is a view showing an image of a liquid crystal panel driven in an inversion method according to a second embodiment.

4 shows a specific image displayed in one frame. Referring to FIG. 4A, the liquid crystal panel includes a plurality of pixels. The pixel includes three subpixels consisting of R, G, and B.

In the inversion scheme according to the second embodiment, the first subpixel group 171 is repeatedly arranged. The first subpixel group 171 may include a second subpixel group 173 and a third subpixel group 175.

The second subpixel group 173 may include two pixels. In other words, it may include six subpixels. The second subpixel group 173 may include a first pixel PX1 and a second pixel PX2. The second subpixel group 173 is driven in the same manner as dot inversion in the second subpixel group 173. In other words, polarities between adjacent subpixels in the second subpixel group 173 are changed. Looking at the first row driven by the same common line, positive polarity may be applied to the R and B subpixels of the first pixel PX1 and the G subpixels of the second pixel PX2, and the first Negative polarity may be applied to the G subpixel of the pixel PX1 and the R and B subpixels of the second pixel PX2.

The third subpixel group 175 may include two pixels. In other words, it may include six subpixels. The third subpixel group 175 may be located adjacent to the second subpixel group 173. The third subpixel group 175 may include a third pixel PX3 and a fourth pixel PX4. The third subpixel group 175 is driven in the same manner as dot inversion in the third subpixel group 175. In other words, the polarity between adjacent subpixels in the third subpixel group 175 is changed. Referring to the first row driven by the same common line, negative polarity may be applied to the R and B subpixels of the third pixel PX3 and the G subpixels of the fourth pixel PX4, and the third Positive polarity may be applied to the G subpixel of the pixel PX3 and the R and B subpixels of the fourth pixel PX4.

Polarities of the second subpixel group 173 and the third subpixel group 175 may be applied in a symmetrical form to the second subpixel group 173 and the third subpixel group 175. .

As a result, the first subpixel group 171 may include twelve subpixels.

The specific pattern for displaying a gray image is displayed on the liquid crystal panel of FIG. 4A. The image displayed on the liquid crystal panel of FIG. 4A is the same image as the image displayed on the liquid crystal panel of FIG. 1A. When the liquid crystal panel is in the normally white mode, a data voltage is applied to the subpixels displayed in black. When the specific pattern is applied, the polarity of the common voltage applied to the common lines arranged in the row direction is not distorted unlike in FIG. 1A.

For example, considering the first row driven by the same common line, the voltage is applied only to the odd pixels PX1, PX3, PX5, and PX7. Examining the subpixels, the first pixel PX1 has a positive polarity applied to the R and B subpixels, and the negative polarity is applied to the G subpixel, and the third pixel PX3 has a positive polarity, R, and B subpixels. Negative polarity is applied to the pixel, R for the fifth pixel PX5, positive polarity is applied to the B subpixel, and negative polarity is applied to the G subpixel, and positive polarity is applied to the G subpixel for the seventh pixel PX7. , A negative polarity is applied to the B subpixel. As a result, the number of subpixels to which positive polarity is applied is the same as the number of subpixels to which negative polarity is applied, so that the image is displayed without distortion of the common voltage to positive or negative polarity, thereby improving display quality and no color difference. .

The specific pattern for displaying a gray image is displayed on the liquid crystal panel of FIG. 4B. The image displayed on the liquid crystal panel of FIG. 4B is the same image as the image displayed on the liquid crystal panel of FIG. 1B. When the specific pattern is applied, the polarity of the common voltage applied to the common lines arranged in the row direction is not distorted unlike in FIG. 1B.

For example, looking at the first row driven by the same common line, voltage is applied only to the third, fourth, seventh and eighth pixels PX3, PX4, PX7, and PX8. In the third pixel PX3, positive polarity is applied to the G subpixel, and negative polarity is applied to the R and B subpixels, and in the fourth pixel PX4, the positive polarity is applied to the R and B subpixels, and the negative polarity is applied to the G subpixel. Is applied, and in the seventh pixel PX7, positive polarity is applied to the G subpixel, and in the case of the eighth pixel PX8, the positive polarity is applied to the R, B subpixel. Negative polarity is applied to the pixel. As a result, the number of subpixels to which positive polarity is applied is the same as the number of subpixels to which negative polarity is applied, so that the image is displayed without distortion of the common voltage to positive or negative polarity, thereby improving display quality and no color difference. .

A specific pattern for displaying a yellow image is displayed on the liquid crystal panel of FIG. 4C. In the image applied to the liquid crystal panel of FIG. 4C, the R and G subpixels of each pixel transmit light, and the B subpixel does not transmit light, thereby displaying a yellow image by combining red and green light. Although the specific pattern is applied, the distortion of the common voltage does not occur, unlike in FIG. 3C, which is partially distorted.

For example, looking at the first row driven by the same common line, the voltage is applied only to the B sub-pixels for every pixel. Positive polarity is applied to the B subpixels of the first, fourth, fifth, and eighth pixels (PX1, PX4, PX5, PX8), and the second, third, sixth, and seventh (PX2, PX3, PX6, PX7 Negative polarity is applied to the subpixel. The number of subpixels to which positive polarity is applied is the same as the number of subpixels to which negative polarity is applied, and there is no portion where the polarity is repeated many times, so that partial common voltage distortion does not occur.

In implementing the first and second embodiments, after applying a data voltage having polarity to the second subpixel group, the polarity is converted using the polarity signal POL applied from the timing controller to the data driver to convert the third subpixel group. The data voltage applied to the first subpixel group may be applied to the data voltage having a polarity opposite to that of the second subpixel group.

Although not shown, in the first and second embodiments, the dot inversion may be driven in the column direction, and the same polarity may be applied in the column direction. It may also be driven in a vertical two-dot inversion manner in the column direction.

10: timing controller 20,120: gate driver
21: gate line 30,130: data driver
31: data line 40: common voltage generator
41: common line 50: pixel area
51: thin film transistor 53: liquid crystal cell
55: parasitic capacitor

Claims

A liquid crystal panel in which a first subpixel group including a predetermined number of subpixels adjacent to a plurality of subpixels in a row direction is repeated;
The first subpixel group includes a second subpixel group and a third subpixel group.
The second subpixel group and the third subpixel group include the same number of subpixels,
And the inverted polarity is applied to the second subpixel group and the third subpixel group.

The method of claim 1,
And wherein the second subpixel group and the third subpixel group are respectively applied with different polarities between adjacent subpixels.

The method of claim 1,
And the second subpixel group and the third subpixel group are each composed of four subpixels.

The method of claim 1,
And the second subpixel group and the third subpixel group each consist of six subpixels.

The method of claim 1,
A data line applying a data voltage to the plurality of subpixels;
A data driver for supplying a data voltage to the data line; And
A timing controller for applying a polarity signal to the data driver to impart polarity to the data line,
And a second polarity is applied to the second subpixel group and the third subpixel group by the polarity signal.

The method of claim 1,
And the subpixels have different polarities between adjacent subpixels in the column direction.

The method of claim 1,
And the subpixels have the same polarity between adjacent subpixels in the column direction.

The method of claim 1,
And the subpixel is driven at a 2-dot inversion perpendicular to the column direction.