KR100546257B1 - Apparatus and method for driving of liquid crystal display - Google Patents

Abstract

The present invention relates to a driving apparatus and method of a liquid crystal display device capable of improving luminance by adjusting a lighting time of each of a plurality of lamps according to a user's command.

The driving device of the liquid crystal display device includes a liquid crystal panel, a plurality of lamps for irradiating light to the liquid crystal panel, control of the liquid crystal panel, and a lighting time of the lamps when a still image is displayed on the liquid crystal panel. On the other hand, when the video is displayed on the liquid crystal panel, a timing controller for reducing the lighting time of the lamps, a controller for generating an analog signal by a user's operation, and a digital signal for converting the analog signal from the controller And a lamp controller for supplying the timing controller.

By such a configuration, the present invention can increase the luminance of the image quality displayed on the liquid crystal panel by adjusting the lighting time of the plurality of lamps by a user's operation, thereby obtaining the image quality of the bright screen desired by the user.

Description

A device and method for driving a liquid crystal display device {APPARATUS AND METHOD FOR DRIVING OF LIQUID CRYSTAL DISPLAY}             

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a schematic diagram illustrating a mechanism of occurrence of moving picture contour degradation when a moving picture is displayed by a display device having a hold characteristic such as a liquid crystal display device;

Fig. 2 is a schematic diagram similar to Fig. 1C in the case where moving picture display is performed in a cathode ray tube having no hold characteristic.

3 is a block diagram showing a driving device of a conventional liquid crystal display.

4 is a cross-sectional view illustrating the backlight unit and the liquid crystal panel illustrated in FIG. 3.

FIG. 5 is a view showing a driving method of a conventional liquid crystal display shown in FIG.

6 is a block diagram illustrating a driving device of a liquid crystal display according to an exemplary embodiment of the present invention.

FIG. 7 is a cross-sectional view illustrating the backlight unit and the liquid crystal panel illustrated in FIG. 6.

FIG. 8 is a view illustrating a method of driving a liquid crystal display according to an exemplary embodiment of the present invention shown in FIG. 6.

<Description of Symbols for Main Parts of Drawings>

2, 102: liquid crystal panel 4, 104: data driver

6, 106: gate driver 8, 108: timing controller

10, 110: backlight unit 12, 112: inverter unit

22, 122: lamp housing 20, 120: diffusion plate

30, 130: lamp 114: lamp control unit

116: regulator

The present invention relates to a driving device and a method of a liquid crystal display device, and more particularly to a driving device and a method of a liquid crystal display device that can improve the brightness by adjusting the lighting time of each of a plurality of lamps according to a user's command.

Liquid crystal displays (hereinafter referred to as "LCDs") have tended to be increasingly wider in scope due to their light weight, thinness, and low power consumption. According to this trend, LCDs are used for office automation equipment, audio / video equipment, and the like. On the other hand, the LCD is controlled to display the desired image on the screen by adjusting the transmission amount of the light beam according to the image signal applied to the plurality of control switches arranged in a matrix form.

LCDs having such a configuration are being replaced by cathode ray tube (CRT) displays due to their thin, low power consumption. The background of this change is the technological innovation of LCD quality improvement. In particular, there is a strong demand for moving picture display represented by television images in recent years, and improvements have been made by liquid crystal materials and driving methods.

However, since the cathode ray tube (CRT) is an impulse light emission by scanning of an electron gun, the LCD is a hold light emission using a backlight unit using a linear lamp (fluorescent light) as an illumination light source, so that complete moving picture display is difficult. That is, when moving image display is performed by the LCD, so-called moving image contour deterioration occurs because of its hold characteristic, and image quality deteriorates.

Fig. 1 is a schematic diagram illustrating a mechanism of occurrence of deterioration of moving picture contours when a moving picture is displayed by a display device having a hold characteristic such as an LCD. Fig. 1 (a) shows a case where white display moving in the arrow direction A is performed on a part of the black background screen of the LCD, and Fig. 1 (b) shows an enlarged view of the black / white boundary portion, Fig. 1 (C) is an explanatory view of the cause of moving image contour deterioration, and FIG. 1 (d) shows an enlarged view similar to that of FIG. 1 (b) showing a moving image contour deterioration state. In FIG. 1, unit rectangles represent pixels. In addition, in FIG. 1, the outline deterioration of a moving picture is designated as "blurred" or "blurred video."

As shown in FIG. 1 (c) in which one row of the black / white boundary portion of FIG. 1 (b) is displayed in time series, the line of sight moves to the lower right side as the display image moves in the direction of the arrow A. FIG. Move diagonally as shown by arrow B. The luminance of the pixels displayed therebetween is maintained even during the movement of one-frame display. Since the luminance is an integral of the luminance of the pixel, moving image contour degradation as shown in Fig. 1D occurs.

On the other hand, in the impulse-type cathode ray tube (CRT), such image contour deterioration does not occur. That is, FIG. 2 is a schematic diagram as shown in FIG. 1C in the case where moving image display is performed in a cathode ray tube (CRT) having no hold characteristic, and pixels are not displayed between movements of images between frames. The moving picture outline deterioration does not occur even if the line of sight moves in the direction of arrow A in the display image as shown by arrow B. FIG. In other words, in the impulse type cathode ray tube (CRT), because black data is displayed between the frame and the new frame, the display image is visually clear due to the black data.

Therefore, as illustrated in FIGS. 1C and 2, the viewer's perceived image is clearly displayed in the cathode ray tube (CRT). On the other hand, in the liquid crystal display device, the display image is blurred due to the retention characteristics of the liquid crystal in the moving image. This difference in perceptual image is due to the integral effect of the image which is temporarily persisted in the eye following the movement. Therefore, even if the response speed of the liquid crystal display is fast, the viewer sees a blurred screen due to a mismatch between eye movement and a static image of every frame.

Accordingly, an LCD according to a backlight sequential driving method using a direct type backlight unit in which a plurality of lamps are arranged horizontally in order to prevent deterioration of a moving image contour of a moving image display has been disclosed.

The LCD according to the backlight sequential driving method turns on a plurality of lamps in synchronization with the start time of the scanning signal of the display image, and when the luminance signal of the same level is supplied, the display luminance of the liquid crystal panel is the luminance value between each frame. By making the time-integrated values of the equals equal, impulse light emission (lighting) equivalent to that of the cathode ray tube (CRT) prevents the deterioration of the moving image contour in moving image display.

3 and 4, a liquid crystal display device driving apparatus according to the prior art includes a liquid crystal panel 2 and a data line of a liquid crystal panel 2 having a data line and a gate line intersecting and having a TFT formed at an intersection thereof. The data driver 4 for supplying data to the data, the gate driver 6 for supplying gate pulses to the gate line of the liquid crystal panel 2, and the plurality of lamps 30 are sequentially turned on to illuminate the liquid crystal panel ( 2) the backlight unit 10 for irradiating light to the light, the inverter unit 12 for controlling the plurality of lamps 30, the data driver 4 and the gate driver 6 and the inverter unit The timing controller 8 which drives the 12 is provided.

As shown in FIG. 4, the backlight unit 10 includes a plurality of lamps 30, a lamp housing 22 surrounding the plurality of lamps 30, and a diffusion plate covering the front surface of the lamp housing 22. 20).

The plurality of lamps 30 are sequentially turned on in response to the control of the inverter unit 12. The lamp housing 22 wraps the plurality of lamps 30 and propagates the light from the plurality of lamps 30 toward the diffuser plate 20 through the reflective surface 24. The diffusion plate 20 allows the light emitted from the plurality of lamps 30 to propagate toward the liquid crystal panel 2 and to be incident at a wide range of angles. Such a diffusion plate 20 uses a light-diffusion member coated on both sides of a film made of a transparent resin.

In the liquid crystal panel 2, liquid crystal is injected between two glass substrates. The TFT formed at the intersection of the data lines and the gate lines of the liquid crystal panel 2 supplies the data on the data lines to the liquid crystal cell in response to a scanning pulse from the gate driver 6. The source electrode of this TFT is connected to the data line, and the drain electrode is connected to the pixel electrode of the liquid crystal cell. The gate electrode of the TFT is connected to the gate line. The liquid crystal panel 2 is stacked on the diffusion plate 20 of the backlight unit 10.

The timing controller 8 rearranges the digital video data supplied from the digital video card (not shown) for each of red (R), green (G), and blue (B). The data RGB rearranged by the timing controller 8 is supplied to the data driver 4. In addition, the timing controller 8 generates a data control signal and a gate control signal using the horizontal / vertical synchronization signals H and V input thereto. The data control signal is supplied to the data driver 4 including a dot clock Dclk, a source shift clock SSC, a source enable signal SOE, a polarity inversion signal POL, and the like. The gate control signal is supplied to the gate driver 6 including a gate start pulse GSP, a gate shift clock GSC, a gate output enable GOE, and the like. In addition, the timing controller 8 controls the inverter unit 12 which sequentially turns on the lamps 30 of the backlight unit 10 when the data is completely supplied to the liquid crystal cell.

After the data driver 4 samples the data according to the data control signal from the timing controller 8, the data driver 4 latches the sampled data by one line and converts the latched data into an analog gamma voltage from a gamma voltage supply (not shown). do.

The gate driver 6 includes a shift register which sequentially generates gate pulses in response to the gate start pulse GSP among the gate control signals from the timing controller 8, and a voltage level suitable for driving the voltage of the gate pulses to drive the liquid crystal cell. And a level shifter for shifting to.

The inverter unit 12 sequentially turns on the plurality of lamps 30 of the backlight unit 10 in response to the lamp control signal from the timing controller 8. That is, the inverter unit 12 sequentially turns on the plurality of lamps 30 after the data voltage is completely supplied to the liquid crystal cell.

In the driving apparatus of the conventional LCD, the plurality of lamps 30 is sequentially turned on when the plurality of gate line groups are driven in one frame as shown in FIG. 5. That is, a gate pulse is applied to the first to first + M gate lines of the N gate lines of the first lamp 30 of the plurality of lamps so that the data voltages are completely supplied to the liquid crystal cell. Lights up and then goes out. In addition, the second lamp is turned on and then turned off when the gate pulse is supplied to the (1 + M) +1 to 1 + 2M gate lines so that the data voltage is completely supplied to the liquid crystal cell. Similarly, the third to nth lamps are turned on and then turned off when the gate pulse is supplied to the corresponding gate lines so that the data voltages are completely supplied to the liquid crystal cells. At this time, the lighting time of each of the plurality of lamps 30 is set to a fixed value according to the size of the liquid crystal panel 2 and the number of lamps.

In the driving apparatus of the liquid crystal display according to the related art, the time for turning on each of the plurality of lamps is set to a fixed value according to the size of the liquid crystal panel 2 and the number of lamps. The brightness and sharpness of the entire screen may not be adjusted depending on the screen to be displayed.

Accordingly, an object of the present invention is to provide a driving apparatus and method of a liquid crystal display device which can improve luminance by adjusting the lighting time of each of a plurality of lamps according to a user's selection.

In order to achieve the above object, the driving device of the liquid crystal display device according to the embodiment of the present invention is a liquid crystal panel, a plurality of lamps for irradiating light to the liquid crystal panel, and the liquid crystal panel in addition to controlling the liquid crystal panel A timing controller for increasing the lighting time of the lamps when a still picture is displayed on the LCD panel, and reducing the lighting time of the lamps when a video is displayed on the LCD panel, and a controller for generating an analog signal by a user's operation. And a ramp controller for converting an analog signal from the regulator into a digital signal and supplying the digital signal to the timing controller.
The driving device of the liquid crystal display further includes at least one inverter for sequentially lighting the plurality of lamps in response to a lamp control signal from the timing controller.
The timing controller reduces the lighting time of the lamps when the value of the digital signal decreases, and increases the lighting time of the lamps when the value of the digital signal increases.
The driving device of the liquid crystal display includes a lamp housing surrounding the plurality of lamps and a diffusion plate disposed between the liquid crystal panel and the lamp housing.
The driving method of the liquid crystal display includes generating an analog signal by a user's operation, converting the analog signal into a digital signal, and sequentially lighting a plurality of lamps in response to the digital signal to the liquid crystal panel. Displaying an image, increasing a lighting time of the lamps when a still picture is displayed on the liquid crystal panel, and decreasing a lighting time of the lamps when a moving image is displayed on the liquid crystal panel.

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Other objects and features of the present invention in addition to the above object will be apparent from the description of the embodiments with reference to the accompanying drawings.

Hereinafter, exemplary embodiments of the present invention will be described with reference to FIGS. 6 to 8.

6 and 7, a driving device of a liquid crystal display according to an exemplary embodiment of the present invention includes a liquid crystal panel 102 and a liquid crystal panel 102 in which a data line and a gate line cross each other and a TFT is formed at an intersection thereof. The data driver 104 for supplying data to the data line of the light source, the gate driver 106 for supplying the gate pulse to the gate line of the liquid crystal panel 102, and the plurality of lamps 130 are sequentially turned on. Controlling the backlight unit 110 for irradiating light to the liquid crystal panel 102, the inverter unit 112 controlling the plurality of lamps 130, the data driver 104 and the gate driver 106. In addition, the timing controller 108 for driving the inverter unit 112, the controller 116 operated by a user's operation, and the analog signal supplied from the controller 116 are converted into digital values to the timing controller 108. The lamp control unit 114 to supply The.

As illustrated in FIG. 7, the backlight unit 110 includes a plurality of lamps 130, a lamp housing 122 surrounding the plurality of lamps 130, and a diffusion plate covering the front surface of the lamp housing 122. 120).

The plurality of lamps 130 are sequentially turned on in response to the control of the inverter unit 112. The lamp housing 122 wraps the plurality of lamps 130 and propagates the light from the plurality of lamps 130 toward the diffuser plate 120 through the reflective surface 124. The diffusion plate 120 allows the light emitted from the plurality of lamps 130 to propagate toward the liquid crystal panel 102, and allows the light to be incident at a wide range of angles. This, the diffusion plate 120 uses a coating of the light diffusion member on both sides of the film made of a transparent resin.

In the liquid crystal panel 102, liquid crystal is injected between two glass substrates. The TFT formed at the intersection of the data lines and the gate lines of the liquid crystal panel 102 supplies the data on the data lines to the liquid crystal cell in response to the scanning pulse from the gate driver 106. The source electrode of this TFT is connected to the data line, and the drain electrode is connected to the pixel electrode of the liquid crystal cell. The gate electrode of the TFT is connected to the gate line. The liquid crystal panel 102 is stacked on the diffusion plate 120 of the backlight unit 110.

The timing controller 108 rearranges the digital video data supplied from the digital video card (not shown) by red (R), green (G), and blue (B). The data RGB rearranged by the timing controller 108 is supplied to the data driver 104. In addition, the timing controller 108 generates a data control signal and a gate control signal using the horizontal / vertical synchronization signals H and V input thereto. The data control signal is supplied to the data driver 104 including a dot clock Dclk, a source shift clock SSC, a source enable signal SOE, a polarity inversion signal POL, and the like. The gate control signal is supplied to the gate driver 106 including a gate start pulse GSP, a gate shift clock GSC, a gate output enable GOE, and the like. In addition, the timing controller 108 controls the inverter unit 112 that sequentially turns on the RAMs of the backlight unit 110 when data is completely supplied to the liquid crystal cell.

After the data driver 104 samples the data according to the data control signal from the timing controller 108, the data driver 104 latches the sampled data by one line and uses the analog gamma voltage from the gamma voltage supply (not shown). Convert.

The gate driver 106 includes a shift register which sequentially generates gate pulses in response to the gate start pulse GSP among the gate control signals from the timing controller 108, and a voltage level suitable for driving the voltage of the gate pulses to drive the liquid crystal cell. And a level shifter for shifting to.

The controller 116 outputs an analog signal from a control circuit including a variable resistor or a variable switch element for controlling a change in luminance value by a user's operation, that is, a lighting time of the plurality of lamps 130, and the lamp controller 114. Supplies). At this time, the user can obtain a desired image quality by adjusting the lighting time of the lamps 130 by operating the controller 116. That is, the user can view the still image in bright image quality by increasing the lighting time of the lamps 130, and reduce the motion blurring of the video by reducing the lighting time of the lamps 130, so that the user can see a clear video quality. have.

The lamp control unit 114 includes an analog-to-digital converter (not shown) for receiving an analog signal from the regulator 116 and converting the analog signal into a digital signal. The analog-to-digital converter converts the corresponding digital value based on the analog signal value from the regulator 116 and supplies it to the timing controller 108. In one example, the analog-to-digital converter converts the analog signal value from the regulator 116 into a 4Bit digital value.

Accordingly, the timing controller 108 controls the inverter unit 112 in response to the digital signal from the lamp control unit 114. For example, when the digital signal from the lamp control unit 114 is "1111", the timing controller 108 supplies a lamp control signal having an on-ime of 100% to the inverter unit 112, In the case of “1100”, the lamp control signal having a lighting time of 50% is supplied to the inverter unit 112.

The inverter unit 112 includes at least one inverter for sequentially lighting the plurality of lamps 130 of the backlight unit 110 in response to the lamp control signal from the timing controller 108. The inverter unit 112 turns on the plurality of lamps 130 in response to the lamp control signal supplied from the timing controller 108. That is, the inverter unit 112 sequentially turns on the plurality of lamps 130 after the data voltage is completely supplied to the liquid crystal cell.

In the driving apparatus of the liquid crystal display according to the exemplary embodiment of the present invention, the plurality of lamps 130 are sequentially turned on when the plurality of gate line groups are driven in one frame as shown in FIG. 8. At this time, the plurality of lamps 130 are turned on during the lighting time by the user's operation. In detail, the first lamp 130 of the plurality of lamps has a gate pulse applied to the first to the first + M gate lines of the N gate lines so that the data voltage is completely applied to the liquid crystal cell. When supplied, it is turned on for the lighting time by user operation and then turned off. In addition, the second lamp is also supplied with gate pulses to the (1 + M) +1 to 1 + 2M gate lines so that during the lighting time by user manipulation when the data voltage is supplied completely to the liquid crystal cell. Lights up and goes out. Similarly, the third to n-th lamps are turned on and then turned off during a lighting operation by a user operation when gate pulses are supplied to corresponding gate lines so that data voltages are completely supplied to the liquid crystal cells.

As such, the driving device and method of the liquid crystal display according to the exemplary embodiment of the present invention allow the user to directly manipulate the controller 116 to display the desired image quality according to a screen displayed on the liquid crystal panel 102. The lighting time of 130 is adjusted. Accordingly, the lighting time of the lamps according to an embodiment of the present invention is increased or decreased by about 20% to 70% compared to the conventional lamps lighting time according to a user's operation to display the image quality desired by the user on the liquid crystal panel 102. It becomes possible.

As described above, the driving apparatus and method of the liquid crystal display according to the exemplary embodiment of the present invention include a lamp controller for adjusting the lighting time of the plurality of lamps by a user's manipulation. Accordingly, the present invention increases the luminance of the image quality displayed on the liquid crystal panel by adjusting the lighting time of the plurality of lamps by the user's operation, thereby obtaining the image quality of the bright screen desired by the user. For example, the present invention can increase the lamp lighting time in the still image to increase the brightness and reduce the lamp lighting time in the video can reduce motion blurring.

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 (9)

LCD panel, A plurality of lamps for irradiating light to the liquid crystal panel, A timing controller which controls the liquid crystal panel and increases the lighting time of the lamps when the still picture is displayed on the liquid crystal panel, while reducing the lighting time of the lamps when the video is displayed on the liquid crystal panel; A controller for generating an analog signal by a user's operation, And a lamp controller for converting an analog signal from the controller into a digital signal and supplying the analog signal to the timing controller. The method of claim 1, And at least one inverter for sequentially lighting the plurality of lamps in response to a lamp control signal from the timing controller. delete The method of claim 1, The timing controller, When the value of the digital signal is reduced to reduce the lighting time of the lamps, And driving time of the lamps increases when the value of the digital signal increases. The method of claim 1, A lamp housing surrounding the plurality of lamps; And a diffuser plate disposed between the liquid crystal panel and the lamp housing. delete Generating an analog signal by a user's operation, Converting the analog signal into a digital signal; Displaying an image on the liquid crystal panel by sequentially lighting a plurality of lamps in response to the digital signal; Increasing the lighting time of the lamps when the still picture is displayed on the liquid crystal panel; And reducing the lighting time of the lamps when a video is displayed on the liquid crystal panel. delete delete

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