KR102019766B1 - Liquid crystal display device and driving method thereof - Google Patents

Liquid crystal display device and driving method thereof Download PDF

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KR102019766B1
KR102019766B1 KR1020120142746A KR20120142746A KR102019766B1 KR 102019766 B1 KR102019766 B1 KR 102019766B1 KR 1020120142746 A KR1020120142746 A KR 1020120142746A KR 20120142746 A KR20120142746 A KR 20120142746A KR 102019766 B1 KR102019766 B1 KR 102019766B1
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South Korea
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pattern
control signal
inversion
gray
image data
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KR1020120142746A
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Korean (ko)
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KR20140074604A (en
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남상진
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엘지디스플레이 주식회사
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    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
    • G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
    • G09G3/34—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source
    • G09G3/36—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source using liquid crystals
    • G09G3/3611—Control of matrices with row and column drivers
    • G09G3/3614—Control of polarity reversal in general
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333—Constructional arrangements; Manufacturing methods
    • G02F1/1345—Conductors connecting electrodes to cell terminals
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G2320/00—Control of display operating conditions
    • G09G2320/02—Improving the quality of display appearance
    • G09G2320/0233—Improving the luminance or brightness uniformity across the screen

Abstract

The present invention relates to a liquid crystal display device. In particular, when a shutdown pattern and a smear pattern are generated at the same time, an inversion method can be changed for the shutdown pattern, and a gray change can be performed for the smear pattern. An object of the present invention is to provide a liquid crystal display and a driving method thereof. To this end, the liquid crystal display according to the present invention, at least one source drive IC; At least one gate drive IC; A receiver which receives a timing signal and input image data; Analyzing the input image data, when a shutdown pattern and a smear pattern are input at the same time, data for changing the gray of the input image data and outputting an inversion control signal for changing the currently driven inversion scheme. Alignment unit; A control signal generation unit configured to change an inversion scheme according to the inversion control signal, and to generate and output a polarity control signal POL corresponding to the changed inversion scheme; And an output unit configured to output image data of which gray is changed and the polarity control signal to the source drive IC, and output a gate control signal transmitted from the control signal generator to the gate drive IC.

Description

Liquid crystal display and its driving method {LIQUID CRYSTAL DISPLAY DEVICE AND DRIVING METHOD THEREOF}

The present invention relates to a liquid crystal display and a driving method thereof.

An active matrix liquid crystal display device displays an image using a thin film transistor (hereinafter, referred to as TFT) as a switching element.

The liquid crystals of the liquid crystal display display an image by changing transmittance according to a potential difference between a data voltage supplied to a pixel electrode and a common voltage supplied to a common electrode. In general, the liquid crystal display device is driven in an inversion method in which the polarity of the data voltage applied to the liquid crystal is periodically inverted to prevent deterioration of the liquid crystal.

When the liquid crystal display is driven in an inversion method, the image quality of the liquid crystal display may be degraded according to the correlation between the polarity of the data voltage charged in the liquid crystal of each pixel and the pattern of the input image data.

The reason is that, depending on the data voltage charged in the liquid crystal of the pixel, the polarities of the data voltages charged in the liquid crystal do not balance the positive and negative polarities, and either polarity becomes the dominant polarity, and therefore, the common electrode This is because the applied common voltage is shifted.

Since the reference potential of each pixel is shaken when the common voltage is shifted, an observer may feel crosstalk, flicker, smear, or the like in an image displayed on the liquid crystal display.

1 and 2 illustrate exemplary problem patterns that may occur in a conventional liquid crystal display. FIG. 1 illustrates a shutdown pattern, and FIG. 2 illustrates a smear pattern. 3 is an exemplary diagram illustrating a state in which the common voltage is shifted in the negative direction by the smear pattern to change the luminance. In particular, in FIGS. 1-3, pixels driven in the normal white mode are shown.

The problem pattern includes a shutdown pattern in which white pixels and black pixels alternate in units of 1 pixel as shown in FIG. 1A, and a white pixel and a white pixel as shown in FIG. 2B. There is a smear pattern in which black pixels alternate every 2 pixels.

First, the shutdown pattern shown in FIG. 1 (b) shows a polarization bias phenomenon in pixels driven by the horizontal 1 dot method (H1dot), and the shutdown pattern shown in FIG. 1 (c) is horizontal. The polarity shift phenomenon in the pixels driven by the two-dot method (H2dot) is shown.

As described above, since the pixels shown in FIG. 1 are driven in normal white, in the shutdown pattern shown in (b) driven by the H1dot method, a common voltage shift occurs in the negative direction, and the H2dot method. The common voltage shift does not occur in the shutdown pattern shown in (c) which is driven by.

In addition, in the square pattern shown in FIG. 2 (b) driven by the H1dot system, no common voltage shift occurs, and in the square pattern shown in (c) driven by the H2dot system, the negative direction is applied. The common voltage sheet is generated.

When the common voltage shift as described above occurs and the common voltage is shifted in the negative direction, as illustrated in FIG. 3, the data voltage having the negative polarity and the positive polarity are shown. Since the charge amount of the data voltage is changed, a luminance difference occurs.

On the other hand, a method for improving the luminance difference due to the above-described problem pattern is disclosed in the Republic of Korea Patent Application No. 10-2009-0075382 (2009.08.14) (hereinafter referred to as "prior document").

The method disclosed in the prior document as described above is to change the inversion method in order to prevent the luminance decrease when the problem pattern is recognized.

However, when the shutdown pattern and the smear pattern appear as described above, the inversion change method as described above cannot be applied.

This is because, as shown in FIGS. 1 and 2, the inversion scheme in which the common voltage shift is generated in the shutdown pattern and the square pattern is different. That is, in the shutdown pattern, as shown in FIG. 1B, a common voltage shift is generated in the H1dot system, and in a square pattern, as shown in FIG. 2B, it is common in the H2dot system. Voltage shift is occurring.

Therefore, when the shutdown pattern and the smear pattern are generated in the same way, even if the entire inversion method of the liquid crystal display device is changed to any one inversion method, the common voltage shift is continuously generated through any one pattern. The decrease in luminance is not improved.

The present invention has been proposed to solve the above-described problem. When the shutdown pattern and the smear pattern are generated at the same time, the inversion method can be changed for the shutdown pattern, and the gray change can be performed for the smear pattern. An object of the present invention is to provide a liquid crystal display and a driving method thereof.

According to an aspect of the present invention, there is provided a liquid crystal display device comprising: at least one source drive IC; At least one gate drive IC; A receiver which receives a timing signal and input image data; Analyzing the input image data, when a shutdown pattern and a smear pattern are input at the same time, data for changing the gray of the input image data and outputting an inversion control signal for changing the currently driven inversion scheme. Alignment unit; A control signal generation unit configured to change an inversion scheme according to the inversion control signal, and to generate and output a polarity control signal POL corresponding to the changed inversion scheme; And an output unit configured to output image data of which gray is changed and the polarity control signal to the source drive IC, and output a gate control signal transmitted from the control signal generator to the gate drive IC.

According to an exemplary embodiment of the present invention, when a shutdown pattern and a square pattern are input at the same time, a gray of the input image data is changed and a currently driven inversion scheme is changed. Outputting an inversion control signal to cause; Changing an inversion scheme according to the inversion control signal, and generating and outputting a polarity control signal (POL) corresponding to the changed inversion scheme; Outputting image data of which gray is changed and the polarity control signal to a source drive IC; And outputting, by the source drive IC, the image data to a data line according to the polarity control signal.

According to the present invention, when the shutdown pattern and the smear pattern are generated at the same time, by changing the inversion method for the shutdown pattern and changing the gray for the smear pattern, the defect and the smear pattern due to the shutdown pattern Even if the defects occur simultaneously, both the defects caused by the shutdown pattern and the defects caused by the smear pattern can be removed.

1 and 2 illustrate exemplary problem patterns that may occur in a conventional liquid crystal display.
3 is an exemplary diagram showing a state in which the common voltage is shifted in the negative direction by the smear pattern and the luminance is changed.
4 is a configuration diagram of an embodiment of a liquid crystal display according to the present invention.
5 is a configuration diagram of an embodiment of a source drive IC applied to a liquid crystal display according to the present invention.
6 is an exemplary view showing an internal configuration of a timing controller applied to a liquid crystal display according to the present invention.
7 is an exemplary view showing in detail a configuration of a data alignment unit of a timing controller applied to a liquid crystal display according to the present invention.
8 is a flowchart of an embodiment of a method of driving a liquid crystal display device according to the present invention;

Hereinafter, with reference to the accompanying drawings will be described in detail an embodiment of the present invention.

4 is a configuration diagram of an embodiment of a liquid crystal display according to the present invention. 5 is a configuration diagram of an embodiment of a source drive IC applied to a liquid crystal display according to the present invention. 6 is an exemplary view showing an internal configuration of a timing controller applied to a liquid crystal display according to the present invention. FIG. 7 is a diagram illustrating in detail a configuration of a data alignment unit of a timing controller applied to a liquid crystal display according to an exemplary embodiment of the present invention, and illustrates an internal configuration of the data alignment unit 430 illustrated in FIG. 6.

As shown in FIG. 4, the liquid crystal display according to the present invention includes a panel 100, at least one gate drive IC (GDIC # 1 to GDIC # 4) 200 for driving the gate lines of the panel, At least one source drive IC (SDIC # 1 to SDIC # 6) 300 for driving the data lines of the panel, and a timing controller 400 for controlling the gate drive IC and the source drive IC. Can be.

First, the panel 100 includes thin film transistors TFTs formed at respective regions defined by intersections of the gate lines and the data lines DL1 to DLm, and pixels including pixel electrodes.

The thin film transistor TFT supplies a data voltage (image signal) supplied from the data line to the pixel electrode in response to a scan signal supplied from the gate line. The pixel electrode adjusts light transmittance by driving a liquid crystal positioned between the common electrode and the common electrode in response to the data voltage.

As for the liquid crystal mode of the panel applied to this invention, not only TN mode, VA mode, IPS mode, FFS mode but any kind of liquid crystal mode is possible. In addition, the liquid crystal display according to the present invention may be implemented in any form, such as a transmissive liquid crystal display, a transflective liquid crystal display, a reflective liquid crystal display.

Next, each of the gate drive ICs GDIC # 1 to GDIC # 4 200 supplies a scan signal to the gate lines using the gate control signals GCS generated by the timing controller 400. . That is, the gate drive IC 200 applied to the present invention may be a gate drive IC applied to a conventional liquid crystal display device as it is.

Meanwhile, as illustrated in FIG. 4, the gate drive IC 200 applied to the present invention may be formed to be independent of the panel 100 and may be configured to be electrically connected to the panel in various ways. However, the gate in panel (GIP) method may be configured in the panel.

The number of gate drive ICs 200 may be set variously according to the size of the panel 100.

Next, the source drive IC 300 converts the digital image data transmitted from the timing controller 400 into a data voltage to convert the data voltage of one horizontal line for every one horizontal period during which a scan signal is supplied to the gate line. Supply to the data lines.

That is, the source drive IC 300 converts the image data into the data voltage using the gamma voltages supplied from a gamma voltage generator (not shown), and then outputs the image data to the data line. To this end, the source drive IC 300, as shown in Figure 5, the shift register unit 310, the latch unit 320, the digital analog converter 330 (DAC) and the output buffer 340 It is included.

As illustrated in FIG. 4, the source drive IC 300 may receive image data from the timing controller 400 using an EPI interface. However, the source drive IC 300 may use the mini-LVDS scheme. Image data may be received from the timing controller 400.

The shift register unit 310 generates a sampling signal using data control signals SSC, SSP, etc. received from the timing controller 400.

The latch unit 320 latches the digital image data Data sequentially received from the timing controller 400, and simultaneously outputs the digital image data to the digital analog converter 330 (DAC). .

The digital-to-analog converter 330 simultaneously converts the image data transmitted from the latch unit 320 into a positive or negative data voltage and outputs the data voltage. That is, the digital analog converter 330 converts the image data into a positive or negative data voltage (data signal) using the polarity control signal POL transmitted from the timing controller to the data lines. Output

In particular, the digital-to-analog converter 330 may convert the polarity of the image data according to the polarity control signal POL transmitted from the timing controller.

That is, when it is determined that the shift of the common voltage due to the shutdown pattern occurs, the timing controller converts the inversion scheme so that the shift of the common voltage due to the shutdown pattern does not occur. Accordingly, the polarity control signal POL is generated and transmitted to the digital analog converter 330. The digital-analog converter 330 converts the image data transmitted from the timing controller according to the converted polarity control signal POL and outputs the converted image data to the data line.

The output buffer 340 transmits the positive or negative data voltage transmitted from the digital analog converter 330 according to the source output enable signal SOE transmitted from the timing controller 400. Output to the data lines of.

The output buffer 340 amplifies the data voltage transmitted from the digital analog converter 330 and outputs the data voltages to the data lines formed in the panel.

The number of the source drive ICs 300 may be variously set according to the size of the panel 100.

Lastly, the timing controller 400 uses a timing signal input from an external system, that is, a vertical synchronization signal Vsync, a horizontal synchronization signal Hsync, a data enable signal DE, and the like. A gate control signal GCS for controlling the operation timing of the 200 and a data control signal DCS for controlling the operation timing of the source drive IC 300 are generated and transmitted to the source drive IC 300. Create image data to be.

In addition, the timing controller 400 analyzes input image data input from the external system and determines whether a shutdown pattern and a smear pattern are output to the input image data.

When the timing controller 400 determines that the shutdown pattern and the smear pattern are output at the same time, the timing controller 400 changes the inversion method so that the common voltage shift due to the shutdown pattern does not occur, and the luminance caused by the smear pattern is changed. In order to prevent degradation, a process of lowering the gray of the input image data as a whole is performed.

To this end, as illustrated in FIG. 6, the timing controller 400 may include a receiver 410 that receives a timing signal and the input image data from an external system, and analyzes the input image data to shutdown patterns and smear patterns. At the same time, it is determined whether the input is simultaneously performed, the gray of the input image data is changed with respect to the smear pattern, and the image data whose gray is changed is output, and an inversion control signal requesting an inversion change by the shutdown pattern is output. A data alignment unit 430 for outputting and generating a gate control signal GCS and a data control signal DCS using the timing signal transmitted from the receiver, and transmitting the inversion control signal from the data alignment unit. In this case, the inversion method is changed to generate a polarity control signal (POL) corresponding to the changed inversion method. The control signal generator 420 and the image data output from the data aligning unit 430 and the data control signal output from the control signal generator 420 to the data driver 300, the control And a transmitter 440 for transmitting the gate control signal output from the signal generator 420 to the gate driver 200.

First, the receiver 410 receives the input image data and the timing signal from the external system and transmits the input image data to the data alignment unit 420. The timing signal received through the receiver 410 may be directly transmitted from the receiver 410 to the control signal generator 420, but the control signal generator 420 passes through the data aligner 420. Can be primed).

Next, the control signal generator 420 controls the timing of the gate control signal and the data driver 300 to control the timing of the gate driver 200 using the timing signals received from the receiver 410. The gate control signal to be generated is generated.

The control signal generator 420 may change the current inversion scheme according to the inversion control signal transmitted from the data alignment unit, and generate a polarity control signal POL according to the changed inversion scheme.

Finally, the data aligning unit 430 analyzes the input image data, and when the shutdown pattern and the smear pattern are input at the same time, the data alignment unit 430 changes the gray of the input image data. It outputs an inversion control signal to change the.

To this end, as illustrated in FIG. 7, the data aligning unit 430 may analyze the input image data to determine whether a shutdown pattern and a smear pattern are simultaneously input. When the shut down pattern and the smear pattern are simultaneously input as a result of the determination of the determination unit, the gray correcting unit 432 for changing the gray of the input image data according to a preset correction value for the input image data. And when the shutdown pattern and the smear pattern are simultaneously input, and the common voltage shift is generated by the shutdown pattern, the common inversion method is not generated. To generate an inversion control signal for outputting the inversion control signal to the control signal generator. Voice portion 433.

Hereinafter, a liquid crystal display driving method according to the present invention configured as described above is described in detail with reference to FIG.

8 is a flowchart illustrating a method of driving a liquid crystal display device according to the present invention.

First, the data aligning unit 430 analyzes the input image data input to the data aligning unit, and changes the gray of the input image data when the shutdown pattern and the smear pattern are input at the same time. An inversion control signal for changing the inversion scheme is output (S802).

In the first embodiment of the present invention, when the gray pattern is changed and the inversion control signal is output (S802), when the shutdown pattern and the square pattern are simultaneously input, the data alignment unit 430 ) Changes the gray of the input image data with respect to the smear pattern, and outputs the image data whose gray is changed.

In the present invention, the reason that the data aligning unit 430 changes the gray of the input image data with respect to the smear pattern is because noise caused by the smear pattern is less perceived by an observer.

That is, as shown in FIG. 2, the smear pattern is a pattern in which white pixels and black pixels alternate in units of 2 pixels, and compared with the shutdown pattern in which white pixels and black pixels alternate in units of 1 pixel. Noise caused by the mare pattern is less noticeable to the observer than noise caused by the shutdown pattern.

Accordingly, the present invention reduces the luminance of the smear pattern so that the noise caused by the smear pattern is less noticeable to the observer.

The gray change may be performed by the gray corrector 432 of the data aligner 430.

In addition, the data aligning unit 430 determines whether a common voltage shift due to the shutdown pattern is occurring.

If it is determined that the common voltage shift due to the shutdown pattern is occurring, the data alignment unit 430 changes the current inversion scheme to an inversion scheme such that the common voltage shift does not occur. An inversion control signal is output to the control signal generator.

However, when no common voltage shift occurs due to the shutdown pattern, the data alignment unit 430 outputs the polarity control signal to the polarity control signal according to a current inversion scheme. Output to the generation unit 420.

That is, even if the smear pattern and the shutdown pattern are generated at the same time, if the common voltage shift due to the shutdown pattern does not occur, deterioration of image quality, noise, etc. are not generated by the shutdown pattern.

Accordingly, the determination unit 431 uses the current inversion method as another inversion method only when the common pattern shift occurs due to the shutdown pattern while the smear pattern and the shutdown pattern occur at the same time. I'm converting.

For example, as described with reference to FIG. 1, even when the smear pattern is generated, the polarity bias phenomenon, that is, the shift of the common voltage, is not generated when the horizontal pattern is driven in the horizontal two-dot method (H2dot).

Accordingly, the determination unit 431 does not change the current inversion method when the smear pattern and the shutdown pattern are generated at the same time, and when the current driving method is the horizontal two-dot method.

However, when the smear pattern and the shutdown pattern are generated at the same time, if the current driving method is the horizontal 1 dot method (H1dot), the determination unit 431 determines that the inversion control signal generation unit 433 is present. Generate the inversion control signal for changing the inversion scheme of the apparatus to a horizontal two-dot scheme (H2dot).

In the second embodiment of the present invention, in the step of changing the gray and outputting the inversion control signal, in step S802, the input image data is analyzed to determine whether a shutdown pattern and a smear pattern are simultaneously input. Judge.

In the first embodiment described above, it is limited to the case where the shutdown pattern and the smear pattern are simultaneously input, but in a situation in which various images are output, any one of the shutdown pattern and the smear pattern Only input may be input or both patterns may not be input.

Accordingly, the determination unit 431 analyzes the input images currently being input, and determines whether the shutdown pattern and the smear pattern are simultaneously input.

As a result of the determination, when the shutdown pattern and the smear pattern are simultaneously input, as in the first embodiment, the gray correction unit 432 changes the gray of the input image data and controls the inversion control. The signal generator 4330 outputs the inversion control signal for changing the currently driven inversion scheme.

As a result of the determination, when only one of the shutdown pattern and the smear pattern is input, the determination unit 431 determines whether the common voltage shift is generated by the shutdown pattern or the smear pattern. .

That is, even when the two patterns are simultaneously output through the panel 100, various types of image quality defects and noise may be generated, but even when any one pattern is output through the panel 100, There may be a difference, but poor image quality and noise are generated.

In addition, as described above, even if the shutdown pattern or the smear pattern is output, noise, such as poor luminance, may or may not be generated depending on an inversion scheme.

Therefore, when it is determined that only one of the two patterns is output, the determination unit 431 determines that the current inversion scheme may generate noise such as poor luminance for the pattern. Determine whether or not the version method.

For example, as described with reference to FIGS. 1 to 3, when the shutdown pattern is driven in the horizontal 1 dot method (H1dot), a common voltage shift occurs to generate a luminance defect, and the smear pattern Is driven in a horizontal two-dot system (H2dot), a common voltage shift occurs, resulting in poor luminance.

Therefore, the determination unit 431 determines what the current inversion method is.

When the common voltage shift is not generated as a result of determining whether the common voltage shift is generated, the inversion control signal generation unit 433 outputs the polarity control signal according to a current inversion scheme. Outputs

In this case, the determination unit 431 may not transmit a special control signal to the inversion control signal generation unit 433, and the inversion control signal generation unit 433 also provides a separate inversion control signal. The control signal generator 420 may not be transmitted. In this case, the control signal generator 420 may generate the polarity control signal POL and transmit the generated polarity control signal POL to the digital-to-analog converter 430 according to an inversion scheme currently output.

When the common voltage shift is generated as a result of the determination of whether the common voltage shift is generated, the inversion control signal generator 433 changes the current inversion scheme to an inversion scheme that prevents the common voltage shift from occurring. The inversion control signal is output to the control signal generator 420.

The gray correction method is applied when the inversion method cannot be applied. In the second embodiment, if only one of two patterns is inputted and luminance decrease and luminance unevenness occur, the gray correction method is performed. By applying the inversion change method, the luminance deterioration and the luminance nonuniformity for the pattern can be eliminated.

That is, when both patterns are output, the inversion method cannot be applied to both patterns. Therefore, the inversion change method is applied only to the shutdown pattern having a large noise removal effect due to the inversion change, and the gray correction method is applied to the smear pattern which can remove some degree of noise by the gray change.

The control signal generator which receives the inversion control signal generates a polarity control signal POL for changing the horizontal one-dot method, which is the current driving method, to the horizontal two-dot method. That is, the control signal generator 420 changes the current inversion scheme according to the inversion control signal and generates a polarity control signal POL corresponding to the changed inversion scheme (S804).

That is, when the gray correction and the inversion scheme change are determined through the above-described process (S802), gray correction is performed in the inversion correction unit 432, and in the control signal generator 420, The polarity control signal POL is generated according to the inversion scheme selected by the inversion control signal.

The output unit 440 outputs the image data whose gray is changed from the gray correcting unit 432 and the polarity control signal transmitted from the control signal generating unit to the source drive IC 300 ( S806). The image data is transmitted to the digital analog converter 330 through the latch unit 320, and the polarity control signal POL is transmitted to the digital analog converter 330.

The image data transmitted to the digital-to-analog converter 330 is changed to a positive or negative data voltage using the polarity control signal and the gamma voltage, and then the panel (eg, through the output buffer 340). The data line is output to the data line formed at 100 (S808).

Meanwhile, in the process of changing the gray and outputting the inversion control signal, the determination unit 431 sets the smear pattern and the shutdown pattern stored in the storage unit 450. The presence of the smear pattern and the shutdown pattern may be determined by comparing the information with the input image data.

That is, the determination unit 431 cannot determine whether the shutdown pattern or the smear pattern is analyzed by analyzing only the input image data, and information indicating which pattern is the shutdown pattern or the smear pattern. Should be.

Such information is stored in the storage unit 450. To this end, the storage unit 450 may be provided on the timing controller 400 or a main board (not shown) on which the timing controller is mounted. .

The shutdown pattern and the method of recognizing the smear pattern may be variously applied.

For example, when the shutdown pattern is detected, when the input image data of the N (N is a positive integer) pixel is white gray (gray) and the input image data of the N + 1 th pixel is black gray The method may further include determining that the input image data forms a shutdown pattern when the count value of the counter is increased by one and the count value is greater than or equal to a predetermined threshold value. In the meantime, in order to recognize the shutdown pattern, patterns that may appear in subpixels must be defined in advance, and these definitions can be stored in the storage 450.

In addition, in the process of changing the gray and outputting the inversion control signal, in operation S802, when the shutdown pattern and the smear pattern correspond to a preset ratio range, The process of changing the gray and outputting the inversion control signal may be performed.

That is, even if the shutdown pattern and the smear pattern are output in some areas of the panel 100, if the two patterns are simultaneously output in a very narrow area compared to the total area of the panel 100, Luminance deterioration and luminance imbalance due to the two patterns are only insignificant.

Therefore, when the output range of the shutdown pattern and the smear pattern does not correspond to a preset ratio range, the timing controller 400 may not perform the gray change process and the inversion change process as described above. It may be.

Further, even when both the shutdown pattern and the smear pattern are output, and the area where the shutdown pattern and the smear pattern is output exceeds a predetermined range, the ratio between the shutdown pattern and the smear pattern is When not included in the preset ratio range, the timing controller 400 may not perform the gray change process and the inversion change process as described above.

For example, when the area where the shutdown pattern and the square pattern are output exceeds 7/10 of the total area of the panel, the area where the square pattern is output is 6 of the total area of the panel. / 10 and the area in which the shutdown pattern is output occupies 1/10 of the total area of the panel, the luminance decrease and luminance imbalance due to the square pattern is lower than the luminance decrease and luminance imbalance due to the shutdown pattern. It will be much larger.

Therefore, in this case, only the polarity control signal POL may be generated according to an inversion scheme in which the common voltage shift due to the shutdown pattern is not generated.

That is, according to the present invention as described above, when the shutdown pattern and the smear pattern are output at the same time, the luminance deterioration and the luminance imbalance due to the patterns can be eliminated. In addition, the present invention can eliminate the luminance deterioration and the luminance imbalance generated when only one of the patterns is output. In addition, even if the two patterns are output at the same time, the inversion method can be changed only for the pattern which causes more serious luminance reduction and luminance imbalance among the two patterns, thereby eliminating the luminance reduction and luminance imbalance. It may be.

Those skilled in the art to which the present invention pertains will understand that the present invention can be implemented in other specific forms without changing the technical spirit or essential features. Therefore, it is to be understood that the embodiments described above are exemplary in all respects and not restrictive. The scope of the present invention is shown by the following claims rather than the detailed description, and all changes or modifications derived from the meaning and scope of the claims and their equivalent concepts should be construed as being included in the scope of the present invention. do.

100: panel 200: gate drive IC
300: source drive IC 400: with timing control
410: receiver 420: gate control signal generator
430: data alignment unit 431: determination unit
432: gray correction unit 433: inversion control signal generation unit
450: storage

Claims (10)

At least one source drive IC;
At least one gate drive IC;
A receiver which receives a timing signal and input image data;
Analyzing the input image data, when a shutdown pattern and a smear pattern are input at the same time, data for changing the gray of the input image data and outputting an inversion control signal for changing the currently driven inversion scheme. Alignment unit;
A control signal generation unit configured to change an inversion scheme according to the inversion control signal, and to generate and output a polarity control signal POL corresponding to the changed inversion scheme; And
An output unit configured to output image data of which gray is changed and the polarity control signal to the source drive IC, and output a gate control signal transmitted from the control signal generator to the gate drive IC,
And the change of the gray is performed on the smear pattern. The method of claim 1,
The data sorting unit,
The gray pattern of the input image data is changed with respect to the smear pattern to output image data of which gray is changed, and when a common voltage shift is generated due to the shutdown pattern, a current inversion scheme is used. And outputting the inversion control signal to the control signal generator to change the inversion method such that shift does not occur. The method of claim 1,
The data sorting unit,
When only one of the shutdown pattern or the smear pattern is input and a common voltage shift caused by the shutdown pattern or the smear pattern is generated, the current inversion scheme is used so that the common voltage shift does not occur. And outputting the inversion control signal to the control signal generator to change the inversion method. The method of claim 1,
The data sorting unit,
And setting information about the smear pattern and the shutdown pattern stored in a storage unit is compared with the input image data to determine whether the smear pattern and the shutdown pattern exist. The method of claim 1,
The data sorting unit,
And changing the gray and outputting the inversion control signal when the shutdown pattern and the smear pattern fall within a preset ratio range. Outputting an inversion control signal for changing the gray of the input image data and changing the currently driven inversion scheme when the shutdown pattern and the square pattern are simultaneously input;
Changing an inversion scheme according to the inversion control signal, and generating and outputting a polarity control signal (POL) corresponding to the changed inversion scheme;
Outputting image data of which gray is changed and the polarity control signal to a source drive IC; And
Outputting, by the source drive IC, the image data to a data line according to the polarity control signal;
And changing the gray is performed on the smear pattern. The method of claim 6,
Changing the gray and outputting the inversion control signal,
When the shutdown pattern and the smear pattern are input at the same time, changing the gray of the input image data with respect to the smear pattern, and outputting image data whose gray is changed;
Determining whether a common voltage shift due to the shutdown pattern is occurring;
Outputting the inversion control signal to change the current inversion scheme to an inversion scheme such that the common voltage shift does not occur when the common voltage shift due to the shutdown pattern is generated; And
And outputting the polarity control signal to output the polarity control signal according to a current inversion scheme when the common voltage shift is not generated due to the shutdown pattern. The method of claim 6,
Changing the gray and outputting the inversion control signal,
Analyzing the input image data to determine whether a shutdown pattern and a square pattern are simultaneously input;
Outputting the inversion control signal to change the gray of the input image data and to change the currently driven inversion scheme when the shutdown pattern and the smear pattern are input simultaneously;
Determining whether a common voltage shift due to the shutdown pattern or the smear pattern is generated when only one of the shutdown pattern and the smear pattern is input;
Outputting the polarity control signal to output the polarity control signal according to a current inversion scheme when the common voltage shift has not occurred as a result of determining whether the common voltage shift has occurred; And
And outputting the inversion control signal to change the current inversion scheme to an inversion scheme such that the common voltage shift does not occur when a common voltage shift occurs as a result of the determination of whether the common voltage shift has occurred. A liquid crystal display driving method comprising the steps. The method of claim 6,
Changing the gray and outputting the inversion control signal,
The setting information about the smear pattern and the shutdown pattern stored in the storage unit is compared with the input image data to determine whether the smear pattern and the shutdown pattern exist. Way. The method of claim 6,
Changing the gray and outputting the inversion control signal,
And changing the gray and outputting the inversion control signal when the shutdown pattern and the smear pattern fall within a preset ratio range.
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