KR20080026278A - Data driving device and driving method thereof - Google Patents

Abstract

The present invention relates to a data driving apparatus and a driving method thereof capable of preventing flicker even when a frequency allocated to one screen uses a low frequency.

The data driving device of the present invention supplies the odd data signal to the odd-numbered liquid crystal cells corresponding to the horizontal line in the odd-numbered frame, and the even data signal to the even-numbered liquid crystal cells corresponding to the horizontal line in the even-numbered frame. A data driver; And a transfer switch unit for supplying an odd data signal and an even data signal to the data driver.

Description

DATA DRIVER DEVICE AND DRIVING MHTHOD THEROF}

1 is a block diagram illustrating a liquid crystal display according to the present invention.

2A and 2B are diagrams illustrating the odd-numbered frame and the even-numbered frame, which illustrate a first embodiment of a liquid crystal display according to the present invention.

FIG. 3 is a diagram illustrating a screen in which two frames illustrated in FIGS. 2A and 2B are combined.

4A and 4B are diagrams illustrating an odd frame and an even frame showing a second embodiment of a liquid crystal display according to the present invention.

FIG. 5 is a diagram illustrating a screen in which two frames illustrated in FIGS. 4A and 4B are combined.

<Description of the symbols for the main parts of the drawings>

106: data driver 108: gate driver

110: timing controller 130: transfer switch unit

132, 134: positive and negative pixel voltages

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a data driving device, and more particularly, to a data driving device and a driving method thereof capable of preventing flicker even when a frequency allocated to one screen uses a low frequency.

The liquid crystal display displays an image by adjusting the light transmittance of the liquid crystal having dielectric anisotropy using an electric field. To this end, the liquid crystal display device includes a liquid crystal display panel for displaying an image and a driving circuit for driving the liquid crystal display panel.

The liquid crystal display panel includes a plurality of gate lines and data lines to drive sub pixels. The driving circuit includes a plurality of data integrated circuits for driving a plurality of data lines and a plurality of gate integrated circuits for driving a plurality of gate lines.

As the specification of the liquid crystal display increases in high resolution, the liquid crystal cells implemented in the odd frame and the liquid crystal cells implemented in the even frame are combined to realize a high resolution in one screen. At this time, the frequency allocated to one screen becomes a low frequency, which causes a problem with flicker.

Accordingly, an object of the present invention is to provide a data driving apparatus and a driving method thereof capable of preventing the flicker phenomenon even when a frequency allocated to one screen uses a low frequency.

In order to achieve the above technical problem, the data driving apparatus of the present invention supplies the odd data signal to the odd-numbered liquid crystal cells corresponding to the horizontal line in the odd-numbered frame, and the even-numbered liquid crystal cells corresponding to the horizontal line in the even-numbered frame. A data driver for supplying an even data signal to the data driver; And a transfer switch unit for supplying an odd data signal and an even data signal to the data driver.

The transfer switch unit includes: a positive and negative switch for supplying positive and negative pixel voltages to the odd-numbered liquid crystal cell corresponding to the horizontal line and the even-numbered liquid crystal cell corresponding to the horizontal line; And first to sixth transfer switches configured to supply odd data signals and even data signals to first to sixth data lines according to signals of the positive and negative switches.

In addition, when the frequency assigned to the odd frame is 60Hz, and the frequency assigned to the even-numbered frame is 60Hz, the frequency allocated to one screen is 30Hz.

On the other hand, when the odd-numbered liquid crystal cells corresponding to the horizontal line receiving the odd data signal in the odd-numbered frame and the even-numbered liquid crystal cells corresponding to the horizontal line receiving the even data signal in the even-numbered frame are combined, Liquid crystal cells of the screen is characterized in that the dot inversion method.

The odd-numbered liquid crystal cells corresponding to the horizontal line receiving the odd data signal in the odd-numbered frame and the even-numbered liquid crystal cells corresponding to the horizontal line receiving the even data signal in the even-numbered frame are combined. The liquid crystal cells of are characterized in that the vertical two-dot inversion method.

In order to achieve the above technical problem, the driving method of the data driving device of the present invention comprises the steps of: generating a radix data signal and even data signal through a transfer switch; And supplying the odd data signal to the odd-numbered liquid crystal cells corresponding to the horizontal line in the odd-numbered frame, and supplying the even-numbered data signal to the even-numbered liquid crystal cells corresponding to the horizontal line in the even-numbered frame. .

Other technical problems and features of the present invention in addition to the above technical problem will become apparent through the description of the embodiments with reference to the accompanying drawings. Hereinafter, exemplary embodiments of the present invention will be described with reference to the accompanying drawings.

1 is a block diagram illustrating a liquid crystal display according to the present invention.

The liquid crystal display shown in FIG. 1 includes a liquid crystal display panel 112 having a pixel matrix, a gate driver 108 for driving gate lines GL1 to GLn of the liquid crystal panel 112, and a liquid crystal panel ( A data driver 106 for driving the data lines DL1 to DLm of the 112, a gate-on voltage Von, a gate-off voltage Voff, a common voltage Vcom required for driving the liquid crystal display, A power supply unit 102 for supplying the gamma voltage GMA, and a timing controller 110 for controlling the driving timing of the gate driver 108 and the data driver 106 are provided.

The timing controller 110 may include a plurality of synchronization signals input from the main body 100 through the connector 14, for example, a data enable (DE) signal for notifying a valid data section input from the outside, and a horizontal synchronization signal ( Multiple gate control signals (GSP, GSC, GOE) using a dot clock (DCLK) that determines the transmission timing of the Hsync, the vertical synchronization signal Vsync, and the pixel data RGB. And generate data control signals SSP, SSC, SOE, and POL, and supply the control signals to the gate driver 108 and the data driver 106. In addition, the timing controller 110 arranges the data signal input from the main body 100 through the connector and supplies the data signal to the data driver 106.

The liquid crystal panel 112 includes a pixel matrix formed of pixels formed at respective regions defined by intersections of the gate lines GL and the data lines DL. Each of the pixels includes a liquid crystal cell Clc for adjusting light transmission amount according to a pixel signal, and thin film transistors TFT for driving the liquid crystal cell Clc.

The thin film transistor TFT is turned on when the thin film transistor TFT is supplied to one of the first and second gate-on voltages Von1 and Von2 to the gate line GL, and transmits a pixel signal from the data line DL to the liquid crystal cell Clc. Supply. When the gate-off voltage VGL is supplied to the gate line GL, the thin film transistor TFT is turned off to maintain the pixel signal charged in the liquid crystal cell Clc.

The liquid crystal cell Clc is equivalently represented by a capacitor, and includes a common electrode facing each other with a liquid crystal interposed therebetween and a pixel electrode connected to the thin film transistor TFT. In addition, the liquid crystal cell Clc further includes a storage capacitor (not shown) so that the charged pixel signal is stably maintained until the next pixel signal is charged. In the liquid crystal cell Clc, an array state of liquid crystals having dielectric anisotropy varies according to pixel signals charged through the thin film transistor TFT, thereby adjusting grayscale.

The power supply unit 102 is supplied with a driving voltage VDD from the outside, and the driving voltage VDD is supplied to the timing controller 110 including the digital circuit, the data driver 106 and the gate driver 108 as a digital driving voltage. Supplied. The power supply unit 102 generates a gate-on voltage VON and a gate-off voltage VOFF using the driving voltage VDD from the outside, supplies the gate-on voltage 108 to the gate driver 108, and generates a common voltage VCOM. The liquid crystal panel 112 is supplied.

The gate driver 108 shifts the gate start pulse GSP from the timing controller 110 according to the gate shift clock GSC to sequentially power the gate lines GL1 to GLm. The scan pulse of the gate-on voltage VGH from 102 is supplied. In this case, the gate driver 108 supplies a scan pulse of the gate-on voltage Von to the liquid crystal panel 112 to the gate lines GL.

The gate driver 108 supplies the gate-off voltage VGL from the power supply 102 in the remaining periods during which the scan pulse of the gate-on voltage VGH is not supplied to the gate lines GL.

In addition, the gate driver 108 controls the pulse width of the scan pulse according to a gate output enable (GOE) signal from the timing controller 110.

The data driver 106 generates a sampling signal by shifting the source start pulse SSP from the timing controller 110 according to the source shift clock SSC. The data driver 106 latches the pixel data RGB according to the SSC according to the sampling signal and supplies the data in units of lines in response to a source output enable (SOE) signal. Subsequently, the data driver 106 converts the gamma voltage from the gamma voltage generator 120 into an analog pixel signal and supplies the pixel data RGB supplied in line units to the data lines DL. Here, the data driver 106 determines the polarity of the pixel signal in response to the polarity control (POL) signal from the timing controller 110 when converting the pixel data into the pixel signal. The data driver 106 determines a period in which the pixel signal is supplied to the data lines DL in response to the source output enable signal SOE. According to the present invention, an odd-numbered liquid crystal cell corresponding to a horizontal line in an odd-numbered frame is turned on, and an even-numbered liquid crystal cell corresponding to a horizontal line in an even-numbered frame is turned on to combine the odd-numbered frame and the even-numbered frame to form a screen. Specifically, when the frequency assigned to the odd frame is, for example, 60 Hz, and the frequency allocated to the even-numbered frame is, for example, 60 Hz, the frequency allocated to one screen is 30 Hz.

2A and 2B illustrate an odd-numbered frame and an even-numbered frame illustrating a first embodiment of a liquid crystal display according to the present invention.

As shown in FIG. 2A, the radix liquid crystal cell corresponding to the horizontal line is turned on during the radix frame. Specifically, the odd-numbered (Nth) vertical lines and the odd-numbered (N-th) horizontal lines cross each other to charge corresponding pixel voltage signals of the positive polarity. The even-numbered (N + 1th) vertical lines and the odd-numbered (N-th) horizontal lines intersect to charge the negative pixel voltage signals in the corresponding liquid crystal cells. In other words, the odd-numbered liquid crystal cells corresponding to the horizontal lines during the odd-numbered frame are charged with positive and negative pixel voltage signals alternately from left to right in the longitudinal direction. Accordingly, the transfer switch unit 130 that can alternately charge the positive and negative pixel voltages is formed. Although the data driver 106 includes a plurality of transfer switch units, one transfer switch unit will be described by way of example.

The transfer switch unit 130 includes positive and negative pixel voltage supplies 132 and 134, positive and negative switches PSW1, PSW2, NSW1, and NSW2 connected to and connected to the positive and negative pixel voltage supplies 132 and 134, and a plurality of transfer switches TS1. To TS6) and a plurality of data lines DL connected to the plurality of transfer switches TS1 to TS6. Here, the transfer switch unit 130 will be described with reference to the first to sixth transfer switches TS1 to TS6 respectively connected to the first to sixth data lines DL1 to DL6.

The positive and negative pixel voltage supply units 132 and 134 distribute and supply the positive and negative pixel voltages to the liquid crystal cells. The positive and negative pixel voltage supplies 132 and 134 may supply the positive or negative pixel voltages to the first to sixth data lines DL1 to DL6 through the positive and negative switches PSW1, PSW2, NSW1, and NSW2. Can be supplied alternately or simultaneously.

The positive and negative switches PSW1, PSW2, NSW1, and NSW2 are formed between the positive and negative pixel voltage supplies 132 and 134 and the first to sixth transfer switches TS1 to TS6. The first and third negative polarity switches PSW1 and NSW1 are connected to the liquid crystal cells corresponding to the horizontal lines of the odd (Nth) and the horizontal lines of the odd (Nth) and the corresponding liquid crystal cells. 5 is connected to the transfer switches TS1, TS3, TS5. In addition, the second positive polarity switch and the second negative polarity switch PSW2 and NSW2 are connected to the corresponding liquid crystal cells by crossing the even-numbered (N + 1) vertical lines and the odd-numbered (N-th) horizontal lines. It is connected to the second, fourth and sixth transfer switches TS2, TS4 and TS6.

The first to sixth transfer switches TS1 to TS6 are connected to the data line DL, and switch the positive and negative pixel voltages on the data line DL at the same time so that the positive and negative electrodes of the liquid crystal display panel 112 can be controlled. It serves to supply polarity pixel voltage signals. Specifically, when the first positive switch PSW1 connected to the first, third, and fifth transfer switches TS1, TS3, TS5 is turned on, the second connected to the second, fourth, and six transfer switches TS2, TS4, TS6. The positive switch PSW2 is turned off. In addition, the second, fourth, and sixth transfer switches TS2, TS4, and TS6 have the second negative polarity switch NSW2 turned on, and the first, the third, and sixth transfer switches TS1, TS3, TS5 have a first negative polarity. The switch NSW1 is turned off. Accordingly, the first, third, and fifth transfer switches TS1, TS3, and TS5 are connected to the positive pixel voltages so that the odd (Nth) vertical lines and the odd (Nth) horizontal lines cross each other. The positive pixel voltage is supplied to the liquid crystal cell. The second, fourth, and sixth transfer switches TS2, TS4, and TS6 are connected to the negative pixel voltages so that the even-numbered (N + 1th) vertical lines and the odd-numbered horizontal lines cross each other to correspond to the negative pixel. Voltage is supplied.

Meanwhile, the first to sixth transfer switches TS1 to TS6 may be randomly divided in addition to the method of distinguishing the first, second, and third transfer switches, and the fourth, fifth, and sixth transfer switches.

As shown in FIG. 2B, the even-numbered liquid crystal cell corresponding to the horizontal line is turned on during the even-numbered frame in the same manner as the transfer switch unit described with reference to FIG. 2A. Specifically, the negative (Nth) vertical lines and the even (N + 1) horizontal lines cross each other to charge the corresponding pixel voltage signals to the corresponding liquid crystal cells. The even-numbered (N + 1) vertical lines and the even-numbered (N + 1) horizontal lines intersect to charge the corresponding pixel voltage signals of the positive polarity. In other words, the even-numbered liquid crystal cells corresponding to the horizontal line during the even-numbered frame are alternately charged with positive and negative pixel voltage signals from left to right in the longitudinal direction. In this way, the positive and negative pixel voltages may be alternately charged through the transfer switch unit 130.

Accordingly, the odd-numbered frame shown in FIG. 2A and the even-numbered frame shown in FIG. 2B are combined so that the polarities of the pixel voltages of the liquid crystal cells adjacent to each of the liquid crystal cells in the horizontal and vertical directions as shown in FIG. The dot inversion method appears differently. In addition, the frequency allocated to one screen becomes a low frequency of 30 Hz.

4A and 4B illustrate a second embodiment of a liquid crystal display according to the present invention.

As shown in FIG. 4A, the radix liquid crystal cell corresponding to the horizontal line is turned on during the radix frame. In detail, the positive (N-th) vertical lines and the 4N-3 (4N-3) horizontal lines cross each other to charge the corresponding pixel voltage signal to the liquid crystal cells. The even-numbered (N + 1) vertical lines and the 4N-1 odd (4N-1) horizontal lines intersect the negative pixel voltage signals in the corresponding liquid crystal cells. In other words, the odd-numbered liquid crystal cells corresponding to the horizontal lines during the odd-numbered frame are charged with positive and negative pixel voltage signals alternately from left to right in the longitudinal direction. In addition, the odd-numbered liquid crystal cells corresponding to the horizontal lines during the odd-numbered frame are alternately charged with positive and negative pixel voltage signals in the width direction. As such, the transfer switch unit 130 is formed to alternately charge the positive and negative pixel voltages. Although the data driver 106 includes a plurality of transfer switch units, one transfer switch unit 130 will be described by way of example.

The transfer switch unit 130 includes positive and negative pixel voltage supplies 132 and 134, positive and negative switches PSW1, PSW2, NSW1, and NSW2 connected to and connected to the positive and negative pixel voltage supplies 132 and 134, and a plurality of transfer switches TS1. To TS6) and a plurality of data lines DL connected to the plurality of transfer switches TS1 to TS6. Here, the transfer switch unit 130 will be described with reference to the first to sixth transfer switches TS1 to TS6 respectively connected to the first to sixth data lines DL1 to DL6.

The positive and negative pixel voltage supply units 132 and 134 distribute and supply the positive and negative pixel voltages to the liquid crystal cells. The positive and negative pixel voltage supplies 132 and 134 may supply the positive or negative pixel voltages to the first to sixth data lines DL1 to DL6 through the positive and negative switches PSW1, PSW2, NSW1, and NSW2. Can be supplied alternately.

The positive and negative switches PSW1, PSW2, NSW1, and NSW2 are formed between the positive and negative pixel voltage supplies 132 and 134 and the first to sixth transfer switches TS1 to TS6. The first and third negative polarity switches PSW1 and NSW1 are connected to the liquid crystal cells corresponding to the horizontal lines of the odd (Nth) and the horizontal lines of the odd (Nth) and the corresponding liquid crystal cells. 5 is connected to the transfer switches TS1, TS3, TS5. In addition, the second positive and second negative polarity switches PSW2 and NSW2 are connected to the corresponding liquid crystal cells by crossing the even-numbered (N + 1th) vertical lines and the odd-numbered (N-th) horizontal lines. It is connected to 2, 4 and 6 transfer switches TS2, TS4 and TS6.

The first to sixth transfer switches TS1 to TS6 are connected to the first to sixth data lines DL1 to DL6, and simultaneously switch the positive and negative pixel voltages on the data line DL so that the liquid crystal display panel ( 112 to supply positive and negative pixel voltage signals. Specifically, when the first positive switch PSW1 connected to the first, third, and fifth transfer switches TS1, TS3, TS5 is turned on, the second connected to the second, fourth, and six transfer switches TS2, TS4, TS6. The positive switch PSW2 is turned off. In addition, the second, fourth, and sixth transfer switches TS2, TS4, and TS6 have the second negative polarity switch NSW2 turned on, and the first, the third, and sixth transfer switches TS1, TS3, TS5 have a first negative polarity. The switch NSW1 is turned off.

The first, third, and fifth transfer switches TS1, TS3, and TS5 are connected to the positive pixel voltage so that the vertical (Nth) vertical lines and the 4N-3th horizontal lines cross each other and are positive in the corresponding liquid crystal cell. Polar pixel voltages are supplied. On the other hand, the negative pixel voltage is supplied through the first, third and fifth transfer switches TS1, TS3 and TS5 to the corresponding liquid crystal cell by crossing the odd (Nth) vertical lines and the 4N-1th horizontal lines. do. As a result, the positive and negative pixel voltages are alternately supplied to the corresponding liquid crystal cell by crossing the odd (N + 1) th vertical lines and the odd (N + 1th) horizontal lines.

The second, fourth, and sixth transfer switches TS2, TS4, and TS6 are connected to the negative pixel voltage, and the liquid crystal cell corresponding to the fourth (N + 1) th vertical line and the 4N-3th horizontal line cross each other. The positive pixel voltage is supplied. On the other hand, the negative pixel is formed through the second, fourth, and sixth transfer switches TS2, TS4, and TS6 corresponding to the even-numbered (N + 1th) vertical lines and the 4N-1th horizontal lines. Voltage is supplied. Accordingly, the positive and negative pixel voltages are alternately supplied to the corresponding liquid crystal cell by crossing the even-numbered (N + 1th) vertical lines and the even-numbered (N + 1th) horizontal lines.

When the frequency of 60 Hz is allocated to the odd-numbered frame of FIG. 4A and the frequency of 60 Hz is allocated to the even-numbered frame of FIG. Further, the even-numbered frame shown in 4a and the even-numbered frame shown in 4b are combined to form a vertical two-dot inversion scheme of the liquid crystal cells as shown in FIG. 5. Therefore, even when a low frequency of 30 Hz to 45 Hz is used for one screen, the liquid crystal cell of the liquid crystal display panel can be realized without a flicker phenomenon.

As described above, in the data driving apparatus and the driving method thereof, when the frequency assigned to the odd frame is 60 Hz and the frequency assigned to the even-numbered frame is 60 Hz, the frequency allocated to one screen combines two frames. The frequency is 30 Hz. Accordingly, the frequency allocated to one screen may use a low frequency.

In addition, the data driving apparatus and the driving method thereof according to the present invention include the odd-numbered liquid crystal cells corresponding to the horizontal line in the odd-numbered frame and the even-numbered liquid crystal corresponding to the horizontal line in the even-numbered frame by providing a transfer switch in the data driver. The liquid crystal cells that combine the cells to form one screen may be implemented in a dot inversion method or a vertical 2 dot inversion method. Therefore, even if the liquid crystal cells are implemented using a low frequency, it is possible to prevent the flicker phenomenon.

In the detailed description of the present invention described above with reference to the preferred embodiment of the present invention, those skilled in the art or those skilled in the art having ordinary knowledge of the present invention described in the claims It will be understood that various modifications and variations can be made in the present invention without departing from the spirit and 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 (7)

A data driver for supplying odd data signals to the odd-numbered liquid crystal cells corresponding to the horizontal line in the odd-numbered frame and supplying even-numbered data signals to the even-numbered liquid crystal cells corresponding to the horizontal line in the even-numbered frame; And a transfer switch unit for supplying an odd data signal and an even data signal to the data driver. The method of claim 1, The transfer switch unit A positive and negative switch for supplying positive and negative pixel voltages to the odd-numbered liquid crystal cell corresponding to the horizontal line and the even-numbered liquid crystal cell corresponding to the horizontal line; And first to sixth transfer switches configured to supply odd data signals and even data signals to first to sixth data lines according to the signals of the positive and negative switches. The method of claim 1, And the frequency assigned to the odd frame is 60 Hz, and the frequency assigned to the even-numbered frame becomes 60 Hz, wherein the frequency allocated to one screen is 30 Hz. The method of claim 1, When the liquid crystal cells corresponding to the horizontal line receiving the odd data signal in the odd frame and the even liquid crystal cells corresponding to the horizontal line receiving the even data signal in the even frame are combined, the liquid crystal of one screen is displayed. And the cells are dot inversion type. The method of claim 1, When the liquid crystal cells corresponding to the horizontal line receiving the odd data signal in the odd frame and the even liquid crystal cells corresponding to the horizontal line receiving the even data signal in the even frame are combined, the liquid crystal of one screen is displayed. And the cells are in a vertical two-dot inversion manner. Generating an odd data signal and an even data signal through a transfer switch; Supplying the odd data signal to the odd-numbered liquid crystal cells corresponding to the horizontal line in the odd-numbered frame, and supplying the even-numbered data signal to the even-numbered liquid crystal cells corresponding to the horizontal line in the even-numbered frame. A method of driving a data drive device. The method of claim 6, And the frequency allocated to the odd frame is 60 Hz, and the frequency assigned to the even-numbered frame is 60 Hz. The frequency allocated to one screen is 30 Hz.

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