KR100843693B1 - Liquid crystal display and driving method thereof - Google Patents

Abstract

The present invention relates to a liquid crystal display device and a driving method thereof capable of implementing a dot inversion driving method using a column inversion driving method.

In the liquid crystal display of the present invention, a plurality of gate lines for supplying a gate signal and a plurality of gate lines are insulated from and intersect with the gate lines and are insulated from adjacent data lines in a zigzag structure to supply a pixel voltage signal. Liquid crystal cells formed at data lines, regions formed at intersections of gate lines and data lines, and thin film transistors connected to any one of the gate lines and any one of the data lines to drive the liquid crystal cells. A liquid crystal panel comprising; A gate driver for supplying a gate signal; And a data driver for supplying the pixel voltage signal and supplying the pixel voltage signal interchangeably with the adjacent pixel voltage signal at predetermined intervals.

Zigzag data line, data exchange

Description

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

1 is a view showing a conventional liquid crystal display device.

2A and 2B are views for explaining a line inversion driving method of a liquid crystal display device.

3A and 3B are views for explaining a column inversion driving method of a liquid crystal display device.

4A and 4B are diagrams for explaining a dot inversion driving method of a liquid crystal display device.

5 illustrates a liquid crystal display according to an exemplary embodiment of the present invention.

FIG. 6 is a block diagram showing a specific configuration of the data driver shown in FIG. 5; FIG.

<Short description of the symbols in the drawings>

2, 12: liquid crystal panel 4, 14: gate driver

6, 16: data driver 20: shift register array

22: Latch Array 24: DAC Array

26: exchanger array 28: buffer array

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device, and more particularly, to a liquid crystal display device and a driving method thereof capable of implementing a dot inversion driving method using a column inversion driving method.

A typical liquid crystal display device displays an image by adjusting light transmittance for each liquid crystal cell according to a video signal. To this end, the liquid crystal display includes a liquid crystal panel in which liquid crystal cells are arranged in a matrix and a driving circuit for driving the liquid crystal panel.

In the liquid crystal panel, liquid crystal cells are positioned in an area formed by intersections of gate lines and data lines. Each of the liquid crystal cells is provided with pixel electrodes and a common electrode for applying an electric field. Each of the pixel electrodes is connected to one of the data lines via a thin film transistor which is a switching element. The gate terminal of the thin film transistor is connected to any one of the gate lines for causing the pixel voltage signal to be applied to the pixel electrodes for one line. The driving circuit includes a gate driver for driving the gate lines, a data driver for driving the data lines, and a common voltage generator for driving the common electrode. The gate driver sequentially supplies the scanning signal, that is, the gate signal to the gate lines, to sequentially drive the liquid crystal cells on the liquid crystal panel by one line. The data driver supplies a pixel voltage signal to each of the data lines whenever a gate signal is supplied to any one of the gate lines. The common voltage generator supplies a common voltage signal to the common electrode. Accordingly, the liquid crystal display device displays an image by adjusting the light transmittance by changing the liquid crystal arrangement state between the pixel electrode and the common electrode according to the pixel voltage signal for each liquid crystal cell.

In fact, the liquid crystal display device includes a liquid crystal panel 2 in which liquid crystal cells are arranged in a matrix form as shown in FIG. 1, and a gate driver 4 for driving gate lines GL1 to GLn of the liquid crystal panel 2. ) And a data driver 6 for driving the data lines DL1 to DLm of the liquid crystal panel 2.

In FIG. 1, the liquid crystal panel 2 is a thin film transistor TFT formed at intersections of liquid crystal cells arranged in a matrix form and n gate lines GL1 to GLn and m data lines DL1 to DLm. ). The thin film transistor TFT supplies a video signal from the data lines DL1 to DLm to the liquid crystal cell in response to the gate signal from the gate lines GL1 to GLn. The liquid crystal cell may be equivalently represented by a liquid crystal capacitor Clc including a common electrode facing the liquid crystal and a pixel electrode connected to the thin film transistor. A storage capacitor (not shown) is further formed in the liquid crystal cell to maintain the data voltage charged in the liquid crystal capacitor Clc until the next data voltage is charged. The storage capacitor is formed between the previous gate electrode and the pixel electrode. The gate driver 4 sequentially supplies gate signals to the gate lines GL1 to GLn to drive the thin film transistors TFT connected to the corresponding gate line. The data driver 6 converts the pixel data into a pixel voltage signal, which is an analog signal, and transmits one horizontal line of video signal to the data lines DL1 through DLm during one horizontal period in which the gate signal is supplied to the gate line GL. Supply. In this case, the data driver converts the pixel data into the pixel voltage signal by using the gamma voltages supplied from the gamma voltage generator (not shown).

In such a liquid crystal display device, a frame inversion system, a line (column) inversion system, and a dot inversion system are used to drive the liquid crystal cells on the liquid crystal panel. The same inversion drive method is used. The frame inversion type liquid crystal panel driving method inverts the polarity of the pixel voltage signal supplied to the liquid crystal cells on the liquid crystal panel every time the frame is changed.

In the line inversion type liquid crystal panel driving method, the polarities of the pixel voltage signals supplied to the liquid crystal panel are inverted for each gate line and every frame on the liquid crystal panel as shown in FIGS. 2A and 2B. This line inversion driving method has a problem in that flicker such as a stripe pattern occurs between horizontal lines as crosstalk between horizontal pixels exists.

In the column inversion type liquid crystal panel driving method, polarities of pixel voltage signals supplied to the liquid crystal panel are inverted according to data lines and frames on the liquid crystal panel as shown in FIGS. 3A and 3B. This column inversion driving method has a problem in that flicker, such as a stripe pattern, occurs between vertical lines as crosstalk exists between vertical pixels.

In the dot inversion liquid crystal panel driving method, as shown in FIGS. 4A and 4B, a pixel voltage signal having a polarity opposite to that of all of the liquid crystal cells adjacent to each other in the horizontal and vertical directions is supplied to each of the liquid crystal cells, and the pixels are frame-by-frame. The polarity of the voltage signal is reversed. In other words, when the video signal of the odd-numbered frame is displayed in the dot inversion method, the process proceeds from the upper left liquid crystal cell to the right liquid crystal cell as shown in FIG. 4A and to the lower liquid crystal cells as shown in FIG. 4A. When the pixel voltage signals are supplied to each of the liquid crystal cells so that the polarity (+) and the negative polarity (-) appear alternately, and the video signal of the even-numbered frame is displayed, as shown in FIG. The pixel voltage signals are supplied to each of the liquid crystal cells so that the negative polarity (-) and the positive polarity (+) alternate with each other as they proceed to the liquid crystal cells of the liquid crystal cells. The dot inversion driving method provides an image with superior image quality than other inversion methods by allowing flickers generated between adjacent pixels in the vertical and horizontal directions to cancel each other.

However, in the dot inversion driving method, since the polarity of the pixel voltage signal supplied to the data lines in the data driver must be reversed in the horizontal and vertical directions, the power consumption increases because the variation of the pixel voltage is larger than that of the other inversion methods. Has its drawbacks.

Accordingly, an object of the present invention is to provide a liquid crystal display device and a driving method thereof which can reduce power consumption by implementing a dot inversion driving method using a column inversion driving method.

In order to achieve the above object, the liquid crystal display device according to the present invention is formed to cross a plurality of gate lines for supplying a gate signal, and insulated from the gate lines and insulated from adjacent data lines in a zigzag structure. A plurality of data lines for supplying a pixel voltage signal, liquid crystal cells formed at regions formed at intersections of gate lines and data lines, and any one of the gate lines and any one of the data lines. A liquid crystal panel comprising a thin film transistor for driving each of them; A gate driver for supplying a gate signal; And a data driver for supplying the pixel voltage signal and supplying the pixel voltage signal interchangeably with the adjacent pixel voltage signal at predetermined intervals.

In this case, the data lines are formed such that adjacent odd-numbered data lines and even-numbered data lines are alternately changed positions for each horizontal line.

The data driver includes a shift register array for supplying a sequential sampling signal, a latch array for latching and outputting pixel data in response to the sampling signal, and a digital-analog converter array for converting pixel data from the latch array into a pixel voltage signal. And an exchanger array for outputting the pixel voltage signal as it is or for exchanging adjacent odd-numbered and even-numbered pixel voltage signals.

In addition, it characterized in that it further comprises a buffer array for buffering and outputting the pixel voltage signal is located at the input terminal or the output terminal of the switch array.

In particular, the exchanger array outputs the pixel voltage signals inputted in the odd horizontal period intact in response to the input control signal, and alternately outputs the 2i-1st and 2ith pixel voltage signals in the even horizontal period. do.

The data driver is driven in a column inversion method, and the liquid crystal panel is driven in a dot inversion method.

A driving method of a liquid crystal display device according to the present invention includes liquid crystal cells arranged in a zigzag shape along a data line formed by crossing the liquid crystal display device with the gate lines insulated and intersecting the adjacent data lines with the zigzag structure. A liquid crystal panel; Converting an input pixel data signal into a pixel voltage signal; And supplying the pixel voltage signal to the data lines at predetermined intervals as it is or to the data lines in exchange with adjacent pixel voltage signals.

In particular, the data lines are formed such that adjacent odd-numbered data lines and even-numbered data lines are alternately changed every horizontal line, and when the pixel voltage signals are exchanged, the adjacent odd-numbered and even-numbered pixel voltage signals are interchanged. It is characterized by.

The supplying of the pixel voltage signal to the data line may include outputting the input pixel voltage signals as they are in the odd horizontal period, and exchanging the 2i-1 and 2ith pixel voltage signals in the even horizontal period. It is characterized by that.                     

The converting of the pixel voltage signal may include converting the input pixel data signal into the pixel voltage signal by a column inversion method, and the liquid crystal panel may be driven by a dot inversion method.

Other objects and advantages of the present invention in addition to the above objects will become apparent from the detailed description of the embodiments with reference to the accompanying drawings.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to FIGS. 5 and 6.

5 illustrates a liquid crystal display according to an exemplary embodiment of the present invention. 5 includes a liquid crystal panel 12 in which liquid crystal cells are arranged in a matrix, a gate driver 14 for driving gate lines GL1 to GLn of the liquid crystal panel 12, and a liquid crystal. A data driver 16 for driving the data lines DL1 to DLm of the panel 12 is provided.

The liquid crystal panel 12 includes a plurality of gate lines GL1 to GLn and data lines DL1 to DLm that cross each other while being insulated from the gate lines GL1 to GLn. In particular, the data lines DL1 to DLm are formed in a zigzag structure intersecting while being insulated from adjacent data lines. In other words, each of the odd-numbered data lines DL1, DL3, ... of the data lines DL1 through DLm alternates with each of the even-numbered data lines DL2, DL4, ... adjacent to each other. To change position. Liquid crystal cells are formed in regions formed at intersections of the gate lines GL1 to GLn and the data lines DL1 to DLm, and the liquid crystal cells are arranged in a matrix form. As the data lines DL1 to DLm are formed in a zigzag shape, the liquid crystal cells connected to the data lines DL1 to DLn are also arranged in a zigzag shape on the liquid crystal panel 12. Specifically, the odd-numbered data lines DL1, DL3, ... are alternately connected to the odd-numbered liquid crystal cell and the even-numbered liquid crystal cell in the horizontal direction for each horizontal line. On the other hand, even-numbered data lines DL2, DL4, ... are alternately connected to the even-numbered liquid crystal cell and the odd-numbered liquid crystal cell in the horizontal direction for each horizontal line.

Each of the liquid crystal cells includes a thin film transistor TFT connected to any one of the n gate lines GL1 to GLn and to any one of the m data lines DL1 to DLm. The thin film transistor TFT supplies the pixel voltage signals from the data lines DL1 to DLm to the liquid crystal cell in response to the gate signals from the gate lines GL1 to GLn. The liquid crystal cell may be equivalently represented by a liquid crystal capacitor Clc including a common electrode (not shown) facing each other with a liquid crystal interposed therebetween and a pixel electrode connected to the thin film transistor. In the liquid crystal cell, a storage capacitor (not shown) is further formed to maintain the data voltage charged in the liquid crystal capacitor Clc until the next data voltage is charged. The storage capacitor is formed between the previous gate electrode and the pixel electrode.

The gate driver 14 sequentially supplies gate signals to the gate lines GL1 to GLn to drive the thin film transistors TFT connected to the corresponding gate line.

The data driver 16 converts the pixel data into a pixel voltage signal, which is an analog signal, and outputs a pixel voltage signal corresponding to one horizontal line during one horizontal period in which the gate signal is supplied to the gate line GL. Supplies). In this case, the data driver 16 converts the pixel data into a pixel voltage signal by using gamma voltages supplied from a gamma voltage generator (not shown). The data driver 16 supplies a pixel voltage signal to the data lines DL1 to DLm in a column inversion driving manner. In other words, the data driver 16 supplies the pixel voltage signals having opposite polarities to the odd-numbered data lines DL1, DL3, ..., and even-numbered data lines DL2, DL4, .... . In particular, the data driver 16 supplies the pixel voltage signals of the odd horizontal lines to the data lines DL1 to DLm as they are for the zigzag data lines DL1 to DLm, while the pixels of the even horizontal line are provided. The voltage signal is supplied by exchanging a 2i-1th pixel voltage signal and a 2ith pixel voltage signal. Accordingly, in the odd data lines DL1, DL3, ..., the data of the odd horizontal line is supplied to the liquid crystal cells in the odd numbered horizontal direction, and the data of the even horizontal line is excellent in the horizontal direction. It supplies to the first liquid crystal cells. On the other hand, in even-numbered data lines DL2, DL4, ..., the data of the even-numbered horizontal line are supplied to the liquid crystal cells that are even-numbered in the horizontal direction, and the data of the even-numbered horizontal line is radiated in the horizontal direction. It supplies to the first liquid crystal cells. The pixel voltage signals driven through the column inversion scheme and supplied through the data driver 16 exchanging the odd and even pixel voltage signals every even horizontal period are zigzag along the zigzag data lines DL1 to DLm. The liquid crystal panel 12 can be driven in a dot inversion manner by being supplied to the liquid crystal cells in the form of a mold.

The driving method of the liquid crystal panel 12 shown in FIG. 5 is described in detail.

First, the first gate line GL1 is driven by a gate high voltage signal applied to the first gate line GL1 in one horizontal period. As a result, the positive polarity (+) pixel voltage signal is supplied to the odd-numbered liquid crystal cells connected to the odd-numbered data lines DL1, DL3, ... by driving the thin film transistors arranged on the first horizontal line. In addition, a negative pixel voltage signal is supplied to even-numbered liquid crystal cells connected to even-numbered data lines DL2, DL4,...

Subsequently, the second gate line GL2 is driven by the gate high voltage signal applied to the second gate line GL2 in the next horizontal period. Accordingly, the pixel electrodes of positive polarity (+) are supplied to the even-numbered liquid crystal cells connected to the odd-numbered data lines DL1, DL3, ... by driving the thin film transistors arranged on the second horizontal line. A negative pixel voltage signal is supplied to the odd-numbered liquid crystal cells connected to the first data lines DL2, DL4,... In this case, in the second horizontal line, the pixel voltages supplied to the first horizontal line as the positions of the odd-numbered data lines DL1, DL3, ... and the even-numbered data lines DL2, DL4, ... are reversed. The pixel voltage signal having a polarity opposite to that of the signal is supplied.

The pixel voltage signals supplied in the column inversion scheme change the odd-numbered and even-numbered pixel voltage signals differently from the pixel voltage signals supplied in the odd-numbered horizontal periods so that the zigzag data lines DL1 through DLm are changed. Accordingly, the liquid crystal panel 12 is driven in a dot inversion manner by being supplied in zigzag form to the liquid crystal cells.

FIG. 6 is a block diagram illustrating a detailed configuration of the data driver shown in FIG. 5. The data driver shown in FIG. 6 includes a shift register array 20 for supplying a sequential sampling signal, a latch array 22 for latching and outputting pixel data in response to the sampling signal, and pixels from the latch array 22. The digital-to-analog conversion (hereinafter referred to as DAC) array 24 for converting data into pixel voltage signals and the pixel voltage signals from the DAC array 24 are output as they are, or the odd and even pixel voltage signals are exchanged. An exchanger array 26 for outputting, and a buffer array 28 for buffering and outputting the pixel voltage signals from the exchanger array 26;

The plurality of shift registers configured in the shift register array 20 sequentially shift the input source start pulse SSP according to the source sampling clock signal SSC to output the sampling signal.

A plurality of latches of the latch array 22 are sequentially latched by sampling input pixel data by a predetermined unit in response to a sampling signal from the shift register array 12 and simultaneously latched in response to a source output enable signal SOE. Output

A plurality of DACs configured in the DAC array 24 converts the pixel data from the latch array 22 into a pixel voltage signal using positive and negative gamma voltages from a gamma voltage unit (not shown). do. In particular, the DAC array 24 converts the odd-numbered and even-numbered pixel data into pixel voltage signals having polarities opposite to each other for outputting the column inversion.

The exchanger array 26 outputs the pixel voltage signals from the DAC array 24 as they are or exchanges the odd and even pixel voltage signals. The exchanger array 26 outputs the pixel voltage signals inputted in the odd-numbered horizontal period through the respective output lines in response to the input control signal, while the 2i-1st and 2i-th pixel voltage signals are output in the even-numbered horizontal period. Replace and output through each output line.

The buffer array 28 buffers the pixel voltage signal output from the exchanger array 26 and outputs the signal to each of the data lines DL1 to DLm.

The data driver 16 having such a configuration converts the pixel data into pixel voltage signals according to the column inversion method, and supplies the pixel voltage signals by changing the radix and even in every even horizontal period. Accordingly, the liquid crystal panel 12 is driven in a dot inversion manner by being supplied in zigzag form to the liquid crystal cells along the zigzag data lines DL1 to DLm. As a result, while the data driver 16 is driven in the column inversion method, the liquid crystal panel 12 can be driven in the dot inversion method, thereby reducing power consumption. Here, the exchanger array 26 may be located at the output side of the buffer array 28.

As described above, the liquid crystal display according to the present invention can implement the dot inversion driving by using the column inversion data driver as the liquid crystal cells are arranged in a zigzag form along the zigzag data line. Accordingly, the liquid crystal display according to the present invention can reduce power consumption when using a conventional dot inversion data driver.

Those skilled in the art will appreciate that various changes and modifications can be made without departing from the technical spirit of the present 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 (11)

A plurality of gate lines for supplying a gate signal, A plurality of data lines insulated from and intersecting with the gate lines and insulated from adjacent data lines in a zigzag structure to supply a pixel voltage signal; Liquid crystal cells formed in regions formed at the intersections of the gate lines and the data lines; A liquid crystal panel connected to any one of the gate lines and one of the data lines and including a thin film transistor to drive each of the liquid crystal cells; A gate driver for supplying the gate signal; And a data driver for supplying the pixel voltage signal and for supplying the pixel voltage signal interchangeably with adjacent pixel voltage signals at predetermined intervals. The method of claim 1, The data lines And an adjacent odd-numbered data line and an even-numbered data line are alternately changed in each horizontal line. The method of claim 1, The data driver A shift register array for supplying a sequential sampling signal; A latch array for latching and outputting pixel data in response to the sampling signal; A digital-analog converter array for converting pixel data from the latch array into a pixel voltage signal; And an exchanger array configured to output the pixel voltage signal as it is or to exchange adjacent odd and even pixel voltage signals. The method of claim 3, wherein And a buffer array positioned at an input terminal or an output terminal of the switch array to buffer and output a pixel voltage signal input thereto. The method of claim 3, wherein The exchanger array outputs the pixel voltage signals inputted in the odd horizontal period intact in response to an input control signal, and alternately outputs the 2i-1st and 2ith pixel voltage signals in the even horizontal period. LCD display device. The method of claim 1, And the data driver is driven in a column inversion method and the liquid crystal panel is driven in a dot inversion method. In the driving method of a liquid crystal display device, The liquid crystal display device includes a liquid crystal panel having liquid crystal cells arranged in a zigzag shape along a data line formed to cross each other while being insulated from gate lines and insulated from adjacent data lines and intersecting in a zigzag structure; Converting an input pixel data signal into a pixel voltage signal; And supplying the pixel voltage signal to the data lines at predetermined intervals or to the data lines in exchange with adjacent pixel voltage signals. The method of claim 7, wherein The data lines are formed such that adjacent odd-numbered data lines and even-numbered data lines alternate their positions every horizontal line. And exchanging adjacent odd-numbered and even-numbered pixel voltage signals when the pixel voltage signals are exchanged. The method of claim 7, wherein Supplying the pixel voltage signal to a data line And outputting the input pixel voltage signals as they are in the odd horizontal period, and exchanging the 2i-1 and 2i pixel voltage signals in the even horizontal period. The method of claim 7, wherein Converting to the pixel voltage signal Converting the input pixel data signal into the pixel voltage signal in a column inversion manner; And the liquid crystal panel is driven by a dot inversion method. The method of claim 1, And the liquid crystal cell is arranged in a zigzag shape along the data line.

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