KR20120117109A - Driving circuit for liquid crystal display device and method for driving the same - Google Patents

Abstract

PURPOSE: A device and method for driving a liquid crystal display device are provided to prevent the deterioration of image quality by applying an optimal inversion driving method to each image quality deterioration area. CONSTITUTION: A liquid crystal panel(2) is divided into a plurality of areas according to the extent of the deterioration of image quality. The areas are operated in a column inversion method. A data driver(4) drives data lines of the liquid crystal panel. A timing controller(8) controls the data driver by generating one bit inversion signal. The timing controller supplies image data to the data driver. [Reference numerals] (4) Data driver; (6) Gate driver; (8) Timing controller

Description

DRIVING CIRCUIT FOR LIQUID CRYSTAL DISPLAY DEVICE AND METHOD FOR DRIVING THE SAME}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display, and in particular, an optimal inversion driving scheme is applied to each region of an image deterioration of a liquid crystal panel, thereby preventing the image deterioration of an image and reducing power consumption so as to drive the liquid crystal display. It relates to a driving method.

The liquid crystal display displays an image by using electrical and optical characteristics of the liquid crystal. Liquid crystals have different anisotropy in refractive index, dielectric constant, etc. according to molecular long axis direction and short axis direction, and can easily adjust molecular arrangement and optical properties. The liquid crystal display using the same displays an image by adjusting the light transmittance through the polarizing plate by changing the arrangement direction of the liquid crystal molecules according to the size of the electric field.

The liquid crystal display includes a liquid crystal panel in which a plurality of pixels are arranged in a matrix, a gate driver driving a gate line of the liquid crystal panel, a data driver driving a data line of the liquid crystal panel, and the like.

In the liquid crystal display device, a frame inversion system, a line inversion system, a column inversion and a dot inversion system are used to drive the pixels of the liquid crystal panel. The same inversion drive method is used.

Among the inversion driving methods, the frame inversion, line inversion and column inversion methods can reduce power consumption compared to the dot inversion method, but crosstalk phenomenon occurs, and an up and down luminance difference occurs. There was a problem of gray matter deterioration. On the other hand, in the case of the dot inversion method, the problem of degradation of the gray may be reduced, and thus, an image having higher image quality may be provided than the frame inversion, line inversion and column inversion methods. However, the dot inversion method has a problem in that the power consumption is too large compared to the line inversion method or the column inversion method.

The present invention is to solve the above problems, the liquid crystal display device that can be driven by reducing the power consumption while preventing the deterioration of the image quality by applying the optimal inversion driving method for each image quality reduction area of the liquid crystal panel And a driving method thereof.

According to an aspect of the present invention, there is provided a driving method of a liquid crystal display device comprising: a liquid crystal panel divided into a plurality of predetermined areas according to a degree of deterioration of a display image; The plurality of divided regions are driven in a column inversion scheme of n × 1 (where n is a natural number of 2 or more), and the data lines of the liquid crystal panel are changed such that the number of inversions is varied for each of the divided regions. A driving data driver; And a timing controller for aligning and supplying image data input from the outside to the data driver, and generating at least one bit of an inversion signal so that the number of inversions varies for each of the plurality of divided regions. Characterized in having a.

The plurality of divided areas may include a rectangular center area positioned at the center of the liquid crystal panel, a first area located closer to the data driver than the center area, a second area located at left and right sides of the center area, and the data driver. And are each divided into third regions located farthest.

The timing controller is configured to maintain the center region in a column inversion manner without any change other than the polarity of the preset order during every frame period, and the first region is the image at least once in addition to the polarity of the set order during every frame period. The polarity of the signal is inverted, the second region is inverted more times than the number of times inverted in the first region, and the third region is more than the number of times inverted in the second region. At least one bit of the inversion signal is generated and supplied to the data driver so as to be inverted a large number of times.

In the center region, when the number of horizontal lines in the center region is k (k is a natural number larger than 2) in the center region, the timing controller supplies image signals to the center region in a k × 1 column inversion scheme. In the first region, when the number of horizontal lines in the first region is k, the first region is supplied with image signals in a column inversion scheme (m is a natural number except 0) of (k / m) × 1. In the second region, when the number of horizontal lines of the second region is k, the second region is supplied with image signals in a column inversion scheme of (k / i) × 1 (i is a natural number larger than m). In addition, in the third region, when the number of horizontal lines in the third region is k, the third region has an image signal in a column inversion scheme of (k / j) × 1 (j is a natural number larger than i). At least so that And generate one bit of said inversion signal, respectively.

The data driver arranges the positive or negative image signals to supply the image signals to the center region in a k × 1 column inversion scheme in response to the at least one bit inversion signal, respectively. And sequentially output the image signals to the corresponding data lines so that the image signals are supplied to the first region in a column inversion scheme of (k / m) × 1. / i) Arrange the image signals so that the image signals are supplied by the column inversion method of x1 and output them to the corresponding data lines, and in the third region, (k / j) x1 column inversion method. The video signals are arranged such that the video signals are supplied and sequentially output to the corresponding data lines.

In addition, the driving method of the liquid crystal display device according to an embodiment of the present invention for achieving the above object is of the liquid crystal display device having a liquid crystal panel divided into a plurality of predetermined areas according to the degree of deterioration of the display image In the driving method, a plurality of divided areas are driven by a column inversion method of n × 1 (where n is a natural number of 2 or more) through a data driver, and the number of inversions of the plurality of divided areas is increased. Driving data lines of the liquid crystal panel to be variable; And generating an inversion signal of at least one bit such that the number of inversions is varied for each of the divided regions, and controlling the data driver.

The divided plurality of areas may include a rectangular center area positioned at the center of the liquid crystal panel, a first area located closer to the data driver than the center area, a second area located at left and right sides of the center area, and the data. The driver may be divided into third regions that are farthest from each other.

Generating each of the inversion signals may allow the center region to be maintained in a column inversion scheme without any other conversion in addition to the polarity of the preset order during each frame period, and the first region may have the polarity in the set order during each frame period. In addition, the polarity of the video signal is inverted at least once, and the second region is inverted more times than the number of times inverted in the first region, and the third region is the second region. Each of the at least one bit of the inversion signal is generated to be inverted more times than the number of times of inversion.

In the controlling of the data driver, when the number of horizontal lines of a predetermined center area is k (k is a natural number greater than 2) in the center area, the image signals are input to the center area by k × 1 column inversion. In the first region, when the number of horizontal lines in the first region is k, the first region has an image signal in a column inversion scheme (m is a natural number except 0) of (k / m) × 1. In the second region, if the number of horizontal lines in the second region is k, the second region has an image of (k / i) × 1 in a column inversion scheme (i is a natural number larger than m). When the signals are supplied and the number of horizontal lines in the third region is k in the third region, a column inversion scheme of (k / j) × 1 in the third region (j is a natural number larger than i). Video signals Characterized by including the step of that class.

The driving of the data lines may include disposing positive or negative image signals so that image signals are supplied to the center region in a k × 1 column inversion manner in response to the at least one bit inversion signal. Sequentially output to the corresponding data lines, and arrange the corresponding image signals so that the image signals are supplied to the first region in a column inversion scheme of (k / m) × 1 and sequentially output to the corresponding data lines. The video signals are arranged in order to supply video signals in a (k / i) × 1 column inversion scheme, and are sequentially output to the corresponding data lines, and in the third region, (k / j) × 1 And arranging the corresponding image signals so that the image signals are supplied in a column inversion manner and sequentially outputting them to the corresponding data lines.

The driving apparatus and driving method thereof according to the present invention having the various features as described above allow the optimal inversion driving method to be applied for each image quality reduction area of the liquid crystal panel, thereby reducing power consumption while reducing image quality. I can drive it.

1 is a circuit diagram illustrating a liquid crystal display according to an exemplary embodiment of the present invention.
2 is a diagram illustrating divided regions of a liquid crystal panel preset according to a degree of deterioration of a display image.
FIG. 3 is a diagram for describing an inversion driving method that is driven differently for each divided region illustrated in FIG. 2.
FIG. 4 is a layout view of image signals supplied to drive a liquid crystal panel as shown in FIG. 3.

Hereinafter, a liquid crystal display and a driving method thereof according to an exemplary embodiment of the present invention having the above characteristics will be described in detail with reference to the accompanying drawings.

1 is a circuit diagram illustrating a liquid crystal display according to an exemplary embodiment of the present invention.

The liquid crystal display shown in FIG. 1 includes a liquid crystal panel 2 divided into a plurality of preset regions according to a degree of deterioration of a display image; A gate driver 6 driving the gate lines GL1 to GLn of the liquid crystal panel 2; The data lines of the liquid crystal panel 2 are driven in a column inversion method of n × 1 (where n is a natural number of 2 or more), and the number of inversions is varied for each of the plurality of divided areas. A data driver 6 for driving (DL1 to DLm); And controlling the data driver 4 by arranging the image data RGB inputted from the outside and supplying the image data RGB to the data driver 4 and generating an inversion signal such that the number of inversions is varied for each of a plurality of divided regions. The timing controller 8 is provided.

The liquid crystal panel 2 is a liquid crystal connected to a TFT and a thin film transistor formed in each pixel area defined by a plurality of gate lines GL1 to GLn and a plurality of data lines DL1 to DLm. Capacitor Clc is provided. The liquid crystal capacitor Clc is composed of a pixel electrode connected to the TFT, and a common electrode disposed with the pixel electrode and the liquid crystal interposed therebetween. The TFT supplies the image signals from the respective data lines DL1 to DLm to the pixel electrodes in response to the scan pulses from the respective gate lines GL1 to GLn. The liquid crystal capacitor Clc charges the difference voltage between the image signal supplied to the pixel electrode and the common voltage, and adjusts the light transmittance by varying the arrangement of the liquid crystal molecules according to the difference voltage. In this case, the storage capacitor Cst may be formed by overlapping the pixel electrode with the storage line and the insulating layer interposed therebetween.

The gate driver 6 sequentially drives the gate lines GL1 to GLn according to the gate control signal GCS from the timing controller 8. Specifically, the gate driver 4 may include a gate start signal (GSP), a gate shift clock (GSC), and a gate output enable (GOE) signal, which is a gate control signal GCS. Etc., the scan pulses having the gate high voltage VGH level are sequentially supplied to the gate lines GL1 to GLn. The gate low voltage is supplied during the remaining period when the scan pulse is not supplied.

The data driver 4 includes a data control signal DCS from the timing controller 8, for example, a source start signal SSP, a source shift clock SSC, and a source output enable signal. The SOE (Source Output Enable) signal, the inversion signal (Pol signal), and the like are used to convert the data Data aligned from the timing controller 8 into an analog voltage, that is, an image signal. Specifically, the data driver 4 latches the data Data aligned through the timing controller 8 according to the SSC, and then scan pulses are supplied to the gate lines GL1 to GLn in response to the SOE signal. Each horizontal line is supplied with one horizontal line of video signal to each of the data lines DL1 through DLm.

In other words, the data driver 4 selects a positive or negative gamma voltage corresponding to the gray value of the data Data aligned according to the inversion signal from the timing controller 8, and displays the selected gamma voltage. The signals are supplied to the data lines DL1 to DLm as signals. In this case, the data driver 4 generates an image signal such that the pixel areas of the liquid crystal panel 2 are driven by a column inversion method of n × 1 (n is a natural number of 2 or more) according to the inversion signal, and in particular, the liquid crystal panel ( The video signal is generated and output so that the number of inversions varies for each of the plurality of divided areas.

The timing controller 8 controls the data driver 4 and the gate driver 6 according to the image data RGB from the outside and the plurality of synchronization signals DCLK, Hsync, Vsync, and DE, respectively. Specifically, the timing controller 8 arranges the image data RGB input from the outside to be suitable for driving the liquid crystal panel 2 and supplies the image data RGB to the data driver 4. The gate control signal GCS and the data control signal (eg, at least one of a sync signal input from the outside, that is, a dot clock DCLK, a data enable signal DE, and horizontal and vertical sync signals Hsync and Vsync) may be used. DCS) is generated and supplied to the gate driver 6 and the data driver 4, respectively. At this time, the timing controller 8 generates an inversion signal so that the number of inversions varies for each divided area of the liquid crystal panel 2, and supplies the inversion signal to the data driver 4.

2 is a diagram illustrating divided regions of a liquid crystal panel preset according to a degree of deterioration of image quality of a display image.

In general, the liquid crystal panel 2 may be driven by a line inversion, column inversion, or dot inversion method. However, each inversion method has advantages and disadvantages, and thus, any inversion set in advance according to the characteristics of the liquid crystal panel 2. The method is applied. For example, when the column inversion scheme in which the polarity of an image signal is converted in units of vertical lines (units of adjacent data lines) of the liquid crystal panel 2 is applied, the degree of deterioration of image quality is different for each divided region illustrated in FIG. 2. Will appear.

In general, the rectangular center area C located at the center of the liquid crystal panel 2 exhibits the least deterioration in image quality when the column inversion method is applied. In addition, the first region (2) located adjacent to the data driver 4 rather than the center region (C) is larger than the center region (C). Next, the degree of deterioration in image quality of the second region ① located at the left and right sides of the center region C is greater than that of the first region ②, and the third region ③ located farthest from the data driver 4 is formed. The degree of deterioration of image quality is greater than that of the second region (1).

As a result, the timing controller 8 may include a plurality of bits in each of the divided regions of the liquid crystal panel 2, that is, the center region C and the first to third regions ①②③, so that the number of polarity inversions of the image signal is different. A version signal is generated and supplied to the data driver 4. Then, the data driver 4 generates and outputs an image signal such that the pixel areas of the liquid crystal panel 2 are driven in a column inversion manner of n × 1 (n is a natural number of two or more) in response to the plurality of inversion signals. In particular, an image signal is generated and output such that the number of inversions varies for each divided area C, ①②③ of the liquid crystal panel 2.

FIG. 3 is a diagram for describing an inversion driving method that is driven differently for each divided region illustrated in FIG. 2.

Referring to FIG. 3, the timing controller 8 of the present invention causes the center region C to be driven in a column inversion manner without conversion in addition to the polarities of the preset order during each frame period, and the first region ②. Generates each inversion signal such that the polarity of the video signal is inverted at least once in addition to the polarities of the set order during each frame period. In addition, in the case of the second region ①, the inversion is performed more times than the number of inversions in the first region ②, and in the case of the third region ③, the second region ① is performed. Each of the inversion signals is generated and supplied to the data driver 4 so as to be inverted more times than the number of times of inversion.

More specifically, when the number of horizontal lines in the center area C is set in k centers (k is a natural number larger than 2) in the center area C, the timing controller 8 is not included in the center area C. An inversion signal is generated to supply image signals in a k × 1 column inversion scheme. In the first area ②, when the number of horizontal lines in the first area ② is k, the column inversion method (m is a natural number excluding 0) of (k / m) × 1 in the first area ②. ) Generates an inversion signal so that the video signals are supplied. In the second region ①, when the number of horizontal lines in the second region ① is k, the second region ① has a column inversion scheme of (k / i) × 1 (i is a natural number larger than m). ) Generates an inversion signal to supply the video signals, and in the third region ③, if the number of horizontal lines of the third region ③ is k, the third region ③ has (k / j) × 1 An inversion signal is generated such that video signals are supplied in a column inversion scheme of (j is a natural number larger than i).

FIG. 4 is a layout view of image signals supplied to drive a liquid crystal panel as shown in FIG. 3.

As shown in FIG. 4, the data driver 4 generates an image signal such that the pixel regions of the liquid crystal panel 2 are driven in a column inversion scheme of n × 1 (n is a natural number of two or more) according to the inversion signal. 3, the video signal is generated and output such that the number of inversions varies for each of a plurality of divided regions of the liquid crystal panel 2.

That is, the data driver 4 arranges the positive or negative image signals so that the image signals are supplied to the center region C in a k × 1 column inversion scheme in response to at least one bit of the inversion signal, respectively. The image signals are sequentially output to the corresponding data lines, and the image signals are arranged and sequentially output to the corresponding data lines so that the image signals are supplied to the first region ② in a column inversion manner of (k / m) × 1. Then, the video signals are arranged in order to supply the video signals in the second region (1) in a column inversion scheme of (k / i) × 1, and are sequentially output to the corresponding data lines. The video signals are arranged and output to the corresponding data lines so that the video signals are supplied in a column inversion manner of k / j) × 1.

As described above, in the driving apparatus and the driving method of the liquid crystal display device of the present invention, the liquid crystal panel 2 is divided into a plurality of regions C, ① ② ③ according to the degree of deterioration of the image quality of the liquid crystal panel 2, By applying the optimal inversion driving method to each divided region (C, ①②③), it is possible to drive while reducing power consumption while preventing image quality deterioration.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention. Therefore, the technical scope of the present invention should not be limited to the contents described in the detailed description of the specification, but should be defined by the claims.

Claims (10)

A liquid crystal panel divided into a plurality of predetermined areas according to a degree of deterioration of a display image;
The plurality of divided regions are driven in a column inversion scheme of n × 1 (where n is a natural number of 2 or more), and the data lines of the liquid crystal panel are changed such that the number of inversions is varied for each of the divided regions. A driving data driver; And
A timing controller for aligning and supplying image data input from the outside to the data driver and generating at least one bit of inversion signal so that the number of inversions of the plurality of divided regions is varied. The drive device of the liquid crystal display device characterized by the above-mentioned. The method of claim 1,
The plurality of divided areas are
A rectangular center region located at the center of the liquid crystal panel;
A first region located closer to the data driver than the center region,
Second regions located on left and right sides of the center region, and
And a third area that is farthest from the data driver. The method of claim 2,
The timing controller is
The center region is maintained in the column inversion method without any conversion other than the polarity of the preset order during each frame period,
The first region is configured to invert the polarity of the video signal at least once in addition to the polarities of the set order during each frame period.
The second region is to be inverted more times than the number of times to be inverted in the first region,
And wherein the third region generates at least one bit of the inversion signal to be supplied to the data driver so that the third region is inverted more times than the number of inversions in the second region. The method of claim 3, wherein
The timing controller is
In the center area, when the number of horizontal lines of the preset center area is k (k is a natural number larger than 2), the center area is supplied with image signals in a k × 1 column inversion scheme.
In the first region, when the number of horizontal lines in the first region is k, the first region is supplied with image signals in a column inversion scheme (m is a natural number except 0) of (k / m) × 1. ,
In the second area, when the number of horizontal lines in the second area is k, the second area is supplied with image signals in a column inversion scheme of (k / i) × 1 (i is a natural number larger than m). In addition,
In the third region, when the number of horizontal lines in the third region is k, the third region is configured such that image signals are supplied to the third region in a column inversion scheme (j is a natural number larger than i) of (k / j) × 1. And driving each of the inversion signals of one bit. The method of claim 4, wherein
The data driver
In response to each of the at least one bit inversion signal, positive and negative image signals are disposed in the center region so that image signals are supplied in a k × 1 column inversion manner, and are sequentially output to the corresponding data lines. ,
The video signals are arranged in the first region so that the video signals are supplied in a column inversion manner of (k / m) × 1 and sequentially output to the corresponding data lines.
In the second region, the image signals are arranged so that the image signals are supplied in a column inversion scheme of (k / i) × 1, and are sequentially output to the corresponding data lines.
And arranging the video signals in the third region so as to supply the video signals in a column inversion manner of (k / j) × 1 and sequentially outputting them to the corresponding data lines. In a driving method of a liquid crystal display device having a liquid crystal panel divided into a plurality of predetermined areas according to the degree of deterioration of the display image,
The liquid crystal panel is driven through a data driver in a column inversion scheme of n × 1 (where n is a natural number of 2 or more), and the number of inversions is varied for each of the divided regions. Driving the data lines of the; And
And controlling the data driver by generating an inversion signal of at least one bit such that the number of inversions is varied for each of the divided regions. 2. The method according to claim 6,
The plurality of divided areas are
A rectangular center region located at the center of the liquid crystal panel;
A first region located closer to the data driver than the center region,
Second regions located on left and right sides of the center region, and
And a third region which is farthest from the data driver. The method of claim 7, wherein
Generating each of the inversion signals
The center region is maintained in the column inversion method without any conversion other than the polarity of the preset order during each frame period,
The first region is configured to invert the polarity of the video signal at least once in addition to the polarities of the set order during each frame period.
The second region is to be inverted more times than the number of times to be inverted in the first region,
And the third region generates at least one bit of the inversion signal to be inverted more times than the number of inversions in the second region. The method of claim 8,
Controlling the data driver
In the center area, when the number of horizontal lines of the preset center area is k (k is a natural number larger than 2), the center area is supplied with image signals in a k × 1 column inversion scheme.
In the first region, when the number of horizontal lines in the first region is k, the first region is supplied with image signals in a column inversion scheme (m is a natural number except 0) of (k / m) × 1. ,
In the second area, when the number of horizontal lines in the second area is k, the second area is supplied with image signals in a column inversion scheme of (k / i) × 1 (i is a natural number larger than m). In addition,
In the third region, when the number of horizontal lines in the third region is k, the third region is configured to supply image signals in a column inversion scheme (j is a natural number larger than i) of (k / j) × 1. A method of driving a liquid crystal display, comprising the steps of: The method of claim 9,
Driving the data lines
In response to each of the at least one bit inversion signal, positive and negative image signals are disposed in the center region so that image signals are supplied in a k × 1 column inversion manner, and are sequentially output to the corresponding data lines. ,
The video signals are arranged in the first region so that the video signals are supplied in a column inversion manner of (k / m) × 1 and sequentially output to the corresponding data lines.
In the second region, the image signals are arranged so that the image signals are supplied in a column inversion scheme of (k / i) × 1, and are sequentially output to the corresponding data lines.
And arranging the video signals in the third region so as to supply the video signals in a column inversion manner of (k / j) × 1 and sequentially outputting them to the corresponding data lines. .

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