KR20110007528A - Liquid crystal display device - Google Patents

Abstract

PURPOSE: A liquid crystal display device is provided to improve the quality of video and solve brightness reduction problem at the same time. CONSTITUTION: A liquid crystal panel has a plurality of pixels crossing a gate line and a data line. A data driving unit(105) supplies the pixel voltage to a data line. A back light(107) is located on back of the liquid crystal panel. The back light supplies the light to the liquid crystal panel.

Description

[0001] LIQUID CRYSTAL DISPLAY DEVICE [0002]

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 capable of improving image quality and preventing luminance decrease.

BACKGROUND ART In general, liquid crystal display devices have tended to be gradually widened due to their light weight, thinness, and low power consumption. Accordingly, the liquid crystal display device is widely used as a portable computer such as a notebook PC, office automation equipment, audio / video equipment, and the like.

In general, a liquid crystal display device displays a desired image on a screen by adjusting the amount of light transmitted according to image signals applied to a plurality of control switching elements arranged in a matrix.

The liquid crystal display device includes a liquid crystal panel in which a color filter substrate as an upper substrate and a thin film transistor array substrate as a lower substrate are opposed to each other, and a liquid crystal layer is filled between the two substrates, and a scan signal and image information are supplied to the liquid crystal panel to provide a liquid crystal. It comprises a drive unit for operating the panel.

Hereinafter, a conventional liquid crystal display device will be described with reference to the accompanying drawings.

As shown in FIG. 1, a conventional liquid crystal display device includes a liquid crystal including a thin film transistor array substrate 1 in which a plurality of pixels are defined by crossing gate lines GL1 to GLn and data lines DL1 to DLm. A panel and a driver which is means for driving the liquid crystal panel are provided.

The driver includes a timing controller 3, a gate driver 4, and a data driver 5.

The timing controller 3 generates a gate control signal and a data control signal for driving the pixels using signals input from the outside, and rearranges and outputs video data from the outside.

The gate driver 4 drives the gate lines GL1 to GLn using the gate control signal supplied from the timing controller 3, and the data driver 5 supplies the data control signal supplied from the timing controller 3. After converting the video data to an analog pixel voltage using the supply to the data lines (DL1 ~ DLm).

The conventional liquid crystal display having such a configuration implements an image by a hold method, so that a motion picture response time is not fast, and thus a user may feel motion blurring. To solve this problem, as shown in FIG. 2, a solution for implementing a video quality improvement mode by displaying an image for some time and displaying a black time for each frame is proposed, but the luminance of the image is reduced due to the black display interval. There have been disadvantages.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to provide a liquid crystal display device in which the image quality of the video is improved and the brightness reduction problem is solved.

According to an exemplary embodiment of the present invention, a liquid crystal panel includes a liquid crystal panel in which a plurality of pixels are defined by crossing gate lines and data lines; A data driver supplying a pixel voltage to the data line; A timing controller which generates a plurality of control signals and rearranges the video data and outputs the data to the data driver, and supplies a black display data to the data driver during a part of each frame section when the first control signal is applied from the outside; Generates a first gamma reference voltage and a second gamma reference voltage having a luminance higher than the first gamma reference voltage, and supplies a first gamma reference voltage to the data driver if the first control signal is not applied to the timing controller. A gamma reference voltage generator configured to supply a second gamma reference voltage to the data driver when a first control signal is applied to the controller; A backlight positioned behind the liquid crystal panel to supply light to the liquid crystal panel; And a backlight driver configured to drive the backlight, and to increase brightness of light emitted from the backlight when a first control signal is applied to a timing controller. It is configured to include.

In the liquid crystal display according to the preferred embodiment of the present invention having the configuration as described above, the black image is implemented for a part of each frame period to increase the luminance of the light emitted from the backlight when the video quality improvement mode is implemented. In each frame section, a high luminance image is implemented for the remaining time except for the time of implementing the black image, thereby improving the image quality of the video and solving the luminance reduction problem.

Hereinafter, a liquid crystal display according to an exemplary embodiment of the present invention will be described in detail with reference to the accompanying drawings.

3 to 5, a liquid crystal display according to an exemplary embodiment of the present invention includes a liquid crystal panel in which a plurality of pixels are defined by crossing gate lines GL1 to GLn and data lines DL1 to DLm; A data driver 105 for supplying a pixel voltage to the data lines DL1 to DLm; Generates a plurality of control signals and rearranges the video data to output the data to the data driver 105. When the first control signal C1 is applied from the outside, a part of each frame section supplies the black display data to the data driver 105. A timing controller 103; Generates a second gamma reference voltage having a luminance higher than the first gamma reference voltage and the first gamma reference voltage, and if the first control signal C1 is not applied to the timing controller 103, the data driver 105 generates a second gamma reference voltage. A gamma reference voltage generator 106 for supplying a first gamma reference voltage and supplying a second gamma reference voltage to the data driver 105 when the first control signal C1 is applied to the timing controller 103; A backlight 107 positioned behind the liquid crystal panel to supply light to the liquid crystal panel; And a backlight driver 108 for driving the backlight 107 and increasing luminance of light emitted from the backlight 107 when the first control signal C1 is applied to the timing controller 103. It is configured to include.

Each component included in the liquid crystal display according to the preferred embodiment of the present invention having such a configuration will be described in detail as follows.

A liquid crystal display according to an exemplary embodiment of the present invention includes a liquid crystal panel including a first substrate 101 which is a thin film transistor array substrate and a second substrate which is a color filter substrate (not shown), and the first substrate of the liquid crystal panel. A liquid crystal layer (not shown) is formed between the 101 and the second substrate.

The first substrate 101 includes a plurality of pixels defined by crossing a plurality of gate lines GL1 to GLn and a plurality of data lines DL1 to DLm.

A thin film transistor is formed in an area where the gate lines GL1 to GLn and the data lines DL1 to DLm of each pixel cross, and a pixel electrode connected to the thin film transistor is formed in each pixel.

Although not shown in the drawing, a common electrode to which a common voltage is supplied is formed on the second substrate (not shown). The common voltage supplied to the common electrode forms a vertical electric field together with the pixel voltage supplied to the pixel electrode to form a liquid crystal. To drive. In this case, the common electrode is formed on the second substrate as an example for convenience of description, and the common electrode is formed on the first substrate 101 so that the common voltage applied to the common electrode is applied to the pixel electrode. The liquid crystal may be driven by forming a horizontal electric field together with the pixel voltage.

Referring to FIG. 3, the liquid crystal display according to the exemplary embodiment of the present invention includes a system 102, a timing controller 103, and a gate driver 104 to drive a plurality of pixels defined on the first substrate 101. ), A data driver 105, a power generator (not shown), and a gamma reference voltage generator 106 are provided.

The system 102 converts the video data input from the outside into the timing controller 103 by converting the video data appropriately to the resolution of the liquid crystal panel, and generates and supplies reference control signals used to drive the liquid crystal panel to the timing controller 103. The driving voltage is supplied to a power generator (not shown).

In addition, the system 102 includes a control signal generator 102a for generating a first control signal C1 and a third control signal C3, wherein the control signal generator 102a allows a user to display video quality. When the improvement mode is selected, the first control signal C1 is generated and applied to the timing controller 103, and the third control signal C3 is generated and applied to the backlight driver 108.

The timing controller 103 generates a gate control signal for controlling the gate driver 104 using the reference control signal input from the system 102, supplies the gate control signal to the gate driver 104, and supplies the data driver 105. A data control signal for controlling is generated and supplied to the gate driver 104, and the video data input from the system 102 is rearranged and supplied to the data driver 105.

The gate control signal includes a gate start pulse (GSP), a gate shift clock (GSC), a gate output enable signal (GOE), and the data control signal is a source start. And a source start pulse (SSP), a source shift clock (SSC), a source output enable signal (SOE), and a polarity control signal (POL).

Referring to FIG. 6, when the first control signal C1 is applied from the system 102, the timing controller 103 supplies black display data to the data driver 105 for some time during each frame period to implement black. The second control signal C2 is applied to the gamma reference voltage generator 106. In this case, when the second control signal C2 is input from the timing controller 103, the gamma reference voltage generator 106 transmits a second gamma reference voltage to the data driver 105 indicating a luminance higher than the first gamma reference voltage. It will be supplied, the detailed description thereof will be described below.

The gate driver 104 sequentially supplies the gate on signal to the gate lines GL1 to GLn by shifting the gate start pulse GSP supplied from the timing controller 103 according to the gate shift clock GSC. As a result, the thin film transistors connected to the corresponding gate lines GL1 to DLn are turned on, and a gate off signal is supplied during a period in which the gate on signal is not supplied to the gate lines GL1 to GLn.

The data driver 105 generates a sampling signal by shifting the source start pulse SSP supplied from the timing controller 103 according to the source shift clock SSC. The data driver 105 generates a sampling signal in response to the sampling signal. After sequentially inputting and latching each other, the data line of one latched horizontal pixel column is converted into an analog pixel voltage using the first or second gamma reference voltage from the gamma reference voltage generator 106 to convert the data line. Supply to (DL1-DLm). Therefore, the pixel voltage is supplied to the pixel electrode connected to the thin film transistor turned on by the gate-on signal.

The power generator (not shown) is required by the timing controller 103, the gate driver 104, the data driver 105, and the gamma reference voltage unit 106 by using the driving voltage supplied from the system 102. Generate multiple power sources.

The gamma reference voltage generator 106 generates a first gamma reference voltage by using the power input from the power generator and generates a second gamma reference voltage having a luminance higher than the first gamma reference voltage, but timing While the second control signal C2 is not input from the controller 103, the first gamma reference voltage is supplied to the data driver 105, and data is input while the second control signal C2 is input from the timing controller 103. The second gamma reference voltage is supplied to the driver 105.

As shown in FIG. 4, the gamma reference voltage generator 106 includes a first gamma reference voltage unit 106a for generating a first gamma reference voltage using a power input from the power generator, and a power generator. A second gamma reference voltage unit 106b for generating a second gamma reference voltage having a luminance higher than the first gamma reference voltage using a power input from the second gamma reference voltage unit 106b, and a second control signal C2 from the timing controller 103; ) Is supplied when the first gamma reference voltage is supplied to the data driver 105, and when the second control signal C2 is input from the timing controller 103, the second gamma reference voltage is supplied to the data driver 105. It is comprised including the part 106c.

That is, when implementing the video quality improvement mode, the timing controller 103 which receives the first control signal C1 from the control signal generator 102a of the system 102 receives the second control signal C2 as a gamma reference voltage. When applied to the generator 106, the gamma reference voltage generator 106 supplies the data driver 105 with the second gamma reference voltage generated by the second gamma reference voltage 106b. ) Converts the video data from the timing controller 103 into an analog pixel voltage having a high luminance by using the second gamma reference voltage and supplies the video data to the pixel electrodes through the data lines DL1 to DLm.

Referring to FIG. 3, a backlight 107 for supplying light to the liquid crystal panel is disposed behind the liquid crystal panel driven by using the plurality of driving means as described above.

The backlight 107 includes a light source and an optical sheet, and in describing the liquid crystal display according to the preferred embodiment of the present invention, a lamp (see 107a in FIG. 5) is used as a light source. The invention is not limited thereto, and various examples will be possible without departing from the spirit of the invention, such as employing a light emitting diode as a light source.

The liquid crystal display according to the preferred embodiment of the present invention is provided with a backlight driver 108 for driving the lamp 107a of the backlight 107. The backlight driver 108 generates a control signal of the system 102. When the third control signal C3 is input from the unit 102a, the luminance of light emitted in driving the lamp 107a of the backlight 107 is increased.

As illustrated in FIG. 5, the backlight driver 108 may include an inverter integrated circuit 108a for converting a direct current power input from the system 102 into an alternating current power using a switching element, and the inverter integrated circuit 108a. A transformer 106b for boosting the AC power from the backlight 107a to the lamp 107a of the backlight 107 and a feedback controller 108d for detecting the tube current of the lamp 107a and supplying it to the pulse width modulator 108c. And a pulse width that receives the tube current of the lamp 107a from the feedback control unit 108d and controls the switching frequency of the switching element of the inverter integrated circuit 108a by using a pulse width modulation signal (PWM). The modulator 108c includes a modulator 108c. The pulse width modulator 108c adjusts the amplitude of the pulse width modulated signal when the third control signal C3 is input from the control signal generator 102a of the system 102. Increasing inverter Increase the enemy duty ratio (duty ratio) of the output AC power to the circuit (108a).

That is, when the third control signal C3 is applied from the control signal generator 102a of the system 102 to the pulse width modulator 108c of the backlight driver 108 by the user selecting the video quality improvement mode, The pulse width modulator 108c increases the amplitude of the pulse width modulated signal to increase the duty ratio of the AC power output of the inverter integrated circuit 108a so that the luminance of the light emitted from the backlight 107 may be increased.

As described above, the liquid crystal display according to the exemplary embodiment of the present invention implements an image having a higher luminance than a normal mode for a part of each frame period and implements a black image for the remaining time when the video quality improvement mode is implemented. In order to implement an image having a higher luminance than a normal mode, the second gamma reference voltage indicating a high luminance is supplied to the data driver, and the luminance of light emitted from the backlight is also increased, but the present invention is not limited thereto. When implementing the video quality improvement mode, an image having a higher luminance than that of the normal mode may be realized by applying only one of a method of supplying a second gamma reference voltage indicating a high luminance to the data driver and a method of increasing the luminance of light emitted from the backlight. There will be.

As described above, the liquid crystal display according to the exemplary embodiment of the present invention implements an image having a higher luminance than a normal mode for a part of each frame period and implements a black image for the remaining time when the video quality improvement mode is implemented. In order to implement an image having a higher luminance than the normal mode, the gamma reference voltage generation unit is configured to include the first and second gamma reference voltage units and the selection unit, but the present invention is not limited thereto. In the implementation, a method of realizing an image having a higher luminance than the normal mode may be various examples such as a method of correcting the video data in the timing controller or the system to display the luminance and supplying the data to the data driver.

That is, the liquid crystal display according to another exemplary embodiment of the present invention includes a liquid crystal panel in which a plurality of pixels are defined by crossing gate lines and data lines; A data driver supplying a pixel voltage to the data line; Generates a plurality of control signals and rearranges the video data and outputs them to the data driver. When the first control signal is applied from the outside, the video data is corrected to have high luminance and supplied to the data driver. A timing controller for supplying display data to the data driver; A gamma reference voltage generator configured to generate a plurality of gamma reference voltages and supply them to the data driver; A backlight positioned behind the liquid crystal panel to supply light to the liquid crystal panel; And a backlight driver configured to drive the backlight, and to increase brightness of light emitted from the backlight when a first control signal is applied to a timing controller. It is configured to include. The system may further include a system for supplying video data and a plurality of reference control signals to the timing controller, wherein the system includes a control signal generator for supplying a first control signal to the timing controller, and generates the control signal. When the first control signal is applied to the timing controller, the controller simultaneously applies the second control signal to the backlight driver to increase the luminance of light emitted from the backlight.

In addition, a liquid crystal display according to another exemplary embodiment of the present invention includes a liquid crystal panel in which a plurality of pixels are defined by crossing gate lines and data lines; A data driver supplying a pixel voltage to the data line; When converting the video data input from the outside to suit the resolution of the liquid crystal panel, and generating and outputting a plurality of reference control signals and first and second control signals, when generating and outputting the first control signal A system for correcting and outputting the video data to exhibit high luminance; A plurality of control signals are generated using the plurality of reference control signals input from the system, and the video data is rearranged and output to the data driver. When the first control signal is applied from the system, a part of each frame section is part of the data driver. A timing controller for supplying black display data; A gamma reference voltage generator configured to generate a plurality of gamma reference voltages and supply them to the data driver; A backlight positioned behind the liquid crystal panel to supply light to the liquid crystal panel; And a backlight driver configured to drive the backlight, and to increase luminance of light emitted from the backlight when a second control signal is applied from the system. It is configured to include.

As described above, the liquid crystal display device according to an exemplary embodiment of the present invention may selectively implement a video quality improvement mode and a general mode by a user's selection. By increasing the brightness of the light and realizing the image with higher luminance than the normal mode for some time in each frame section and the black image for the rest of the time, the image quality is improved and the luminance reduction problem is solved. have.

1 is a block diagram showing a conventional general liquid crystal display device.

FIG. 2 is a timing diagram illustrating a video quality improvement mode in FIG. 1.

3 is a block diagram illustrating a liquid crystal display according to a preferred embodiment of the present invention.

4 is a block diagram illustrating an example of a configuration of a gamma reference voltage generator of FIG. 3.

FIG. 5 is a block diagram illustrating an example of a configuration of a backlight driver of FIG. 3.

6 is a timing diagram illustrating a video quality improvement mode in FIG. 3.

** Description of the symbols for the main parts of the drawings **

101: first substrate 102: system

102a: control signal generator 103: timing controller

104: gate driver 105: data driver

106: gamma reference voltage generation unit 106a: first gamma reference voltage unit

106b: second gamma reference voltage section 106c: selection section

107: backlight 107a: lamp

108: backlight driver 108a: inverter integrated circuit

108b: transformer 108c: pulse width modulator

108d: feedback control unit

Claims (13)

A liquid crystal panel in which a plurality of pixels are defined by crossing gate lines and data lines; A data driver supplying a pixel voltage to the data line; A timing controller which generates a plurality of control signals and rearranges the video data and outputs the data to the data driver, and supplies a black display data to the data driver during a part of each frame section when the first control signal is applied from the outside; Generates a first gamma reference voltage and a second gamma reference voltage having a luminance higher than the first gamma reference voltage, and supplies a first gamma reference voltage to the data driver if the first control signal is not applied to the timing controller. A gamma reference voltage generator configured to supply a second gamma reference voltage to the data driver when a first control signal is applied to the controller; A backlight positioned behind the liquid crystal panel to supply light to the liquid crystal panel; And A backlight driver configured to drive the backlight and increase luminance of light emitted from the backlight when a first control signal is applied to a timing controller; Liquid crystal display device comprising a. The method of claim 1, wherein when the first control signal is input, the timing controller applies a second control signal to the gamma reference voltage generator so that the gamma reference voltage generator supplies the second gamma reference voltage to the data driver. Liquid crystal display device. The method of claim 2, wherein the gamma reference voltage generator, A first gamma reference voltage unit generating a first gamma reference voltage; A second gamma reference voltage unit configured to generate a second gamma reference voltage; And A selector configured to supply a first gamma reference voltage to the data driver when the second control signal is not input from the timing controller, and to supply a second gamma reference voltage to the data driver when the second control signal is input from the timing controller; Liquid crystal display device comprising a. The system of claim 1, further comprising a system for supplying video data and a plurality of reference control signals to the timing controller. The system includes a control signal generator for supplying a first control signal to the timing controller, wherein the control signal generator is configured to simultaneously apply a third control signal to the backlight driver to provide a first control signal to the timing controller, thereby providing a control signal from the backlight. A liquid crystal display device, characterized in that to increase the brightness of the emitted light. The method of claim 4, wherein the backlight driver, An inverter integrated circuit for converting DC power applied from the system into AC power using a switching element; A transformer for boosting AC power from the inverter integrated circuit and supplying it to the backlight; And The operation of the switching element of the inverter integrated circuit is controlled by using a pulse width modulated signal, and when a third control signal is applied from the system, the amplitude of the pulse width modulated signal is increased so that the duty ratio of the AC power source output of the inverter integrated circuit is increased. A pulse width modulator for increasing the value; Liquid crystal display device comprising a. A liquid crystal panel in which a plurality of pixels are defined by crossing gate lines and data lines; A data driver supplying a pixel voltage to the data line; A timing controller which generates a plurality of control signals and rearranges the video data and outputs the data to the data driver, and supplies a black display data to the data driver during a part of each frame section when the first control signal is applied from the outside; Generates a first gamma reference voltage and a second gamma reference voltage having a luminance higher than the first gamma reference voltage, and supplies a first gamma reference voltage to the data driver if the first control signal is not applied to the timing controller. A gamma reference voltage generator configured to supply a second gamma reference voltage to the data driver when a first control signal is applied to the controller; Liquid crystal display device comprising a. The method of claim 6, wherein the timing controller, when the first control signal is input, applies the second control signal to the gamma reference voltage generator to cause the gamma reference voltage generator to supply the second gamma reference voltage to the data driver. Liquid crystal display device. The method of claim 7, wherein the gamma reference voltage generator, A first gamma reference voltage unit generating a first gamma reference voltage; A second gamma reference voltage unit configured to generate a second gamma reference voltage; And A selector configured to supply a first gamma reference voltage to the data driver when the second control signal is not input from the timing controller, and to supply a second gamma reference voltage to the data driver when the second control signal is input from the timing controller; Liquid crystal display device comprising a. A liquid crystal panel in which a plurality of pixels are defined by crossing gate lines and data lines; A data driver supplying a pixel voltage to the data line; Generates a plurality of control signals and rearranges the video data and outputs them to the data driver. When the first control signal is applied from the outside, the video data is corrected to have high luminance and supplied to the data driver. A timing controller for supplying display data to the data driver; A gamma reference voltage generator configured to generate a plurality of gamma reference voltages and supply them to the data driver; A backlight positioned behind the liquid crystal panel to supply light to the liquid crystal panel; And A backlight driver configured to drive the backlight and increase luminance of light emitted from the backlight when a first control signal is applied to a timing controller; Liquid crystal display device comprising a. The system of claim 9, further comprising a system for supplying video data and a plurality of reference control signals to the timing controller. The system includes a control signal generator for supplying a first control signal to the timing controller, wherein the control signal generator is configured to simultaneously apply a second control signal to the backlight driver to provide a first control signal to the timing controller, thereby preventing from the backlight. A liquid crystal display device, characterized in that to increase the brightness of the emitted light. The method of claim 10, wherein the backlight driver, An inverter integrated circuit for converting DC power applied from the system into AC power using a switching element; A transformer for boosting AC power from the inverter integrated circuit and supplying it to the backlight; And A pulse width modulated signal is used to control the operation of the switching element of the inverter integrated circuit. When a second control signal is applied from the system, the amplitude ratio of the pulse width modulated signal is increased to increase the duty ratio of the AC power source that is the output of the inverter integrated circuit. A pulse width modulator for increasing the value; Liquid crystal display device comprising a. A liquid crystal panel in which a plurality of pixels are defined by crossing gate lines and data lines; A data driver supplying a pixel voltage to the data line; When converting the video data input from the outside to suit the resolution of the liquid crystal panel, and generating and outputting a plurality of reference control signals and first and second control signals, when generating and outputting the first control signal A system for correcting and outputting the video data to exhibit high luminance; Generates a plurality of control signals using the plurality of reference control signals input from the system and rearranges the video data and outputs the data to the data driver. When the first control signal is applied from the system, part of each frame section is part of the data driver. A timing controller for supplying black display data; A gamma reference voltage generator configured to generate a plurality of gamma reference voltages and supply them to the data driver; A backlight positioned behind the liquid crystal panel to supply light to the liquid crystal panel; And A backlight driver configured to drive the backlight and increase brightness of light emitted from the backlight when a second control signal is applied from the system; Liquid crystal display device comprising a. The method of claim 12, wherein the backlight driver, An inverter integrated circuit for converting DC power applied from the system into AC power using a switching element; A transformer for boosting AC power from the inverter integrated circuit and supplying it to the backlight; And A pulse width modulated signal is used to control the operation of the switching element of the inverter integrated circuit. When a second control signal is applied from the system, the amplitude ratio of the pulse width modulated signal is increased to increase the duty ratio of the AC power source that is the output of the inverter integrated circuit. A pulse width modulator for increasing the value; Liquid crystal display device comprising a.

Images