KR20070078002A - Gray-scale voltage producing module and liquid crystal display having the same and driving method thereof - Google Patents

Abstract

A grayscale voltage generating module, a liquid crystal display having the same and a driving method thereof are provided to facilitate RGB color calibration by applying different grayscale voltages to respective RGB pixels. A grayscale voltage generating module includes a first voltage input terminal, a second voltage input terminal, at least one LCD(Liquid Crystal Display) driving voltage converter(610,620,630,640), and grayscale generators(650,660). An LCD driving voltage is input to the first voltage input terminal. A ground voltage is input to the second voltage input terminal. The LCD driving voltage converters(610,620,630,640) generate LCD driving voltages with different levels according to RGB data. The grayscale generators generate different grayscale voltages according to the LCD driving voltages.

Description

Gradient voltage generation module, liquid crystal display including the same and driving method thereof {GRAY-SCALE VOLTAGE PRODUCING MODULE AND LIQUID CRYSTAL DISPLAY HAVING THE SAME AND DRIVING METHOD THEREOF}

1 is a block diagram of a liquid crystal display according to an exemplary embodiment of the present invention.

2 is a block diagram of a data driver according to the present embodiment.

3 is a circuit diagram of a gray voltage generator according to an exemplary embodiment of the present invention.

4 is a graph showing luminance of R, G, and B pixels according to an applied gray voltage.

5 is a conceptual diagram illustrating a voltage adjusting method according to an embodiment of the present invention.

Figure 6 is a graph showing the voltage for each gray level applied to the R, G, B pixels through the gray voltage generator according to the present invention.

7 is a circuit diagram of a gray voltage generator according to a first modification of the present embodiment.

8 is a circuit diagram of a gray voltage generator according to a second modification of the present embodiment.

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

100: liquid crystal display panel 200: gate driver

300: data driver 400; Signal controller

500: driving voltage generator 600: gray voltage generator

610, 620, 630, 640: voltage converter 650, 660: gradation voltage generating means

The present invention relates to a gray scale voltage generating module, a liquid crystal display including the same, and a driving method thereof, wherein the gray scale voltage generating module can improve color coordinate adjustment and luminance by applying different gray voltages to R, G, and B, respectively. And a liquid crystal display including the same and a driving method thereof.

Liquid crystal display devices (LCDs) have advantages of small size, light weight, and large screen compared with conventional display devices, such as cathode ray tubes (CRTs), and their development is being actively performed.

In the liquid crystal display, two substrates on which electrodes are formed are disposed so that the two electrodes face each other, a liquid crystal material is injected between the two substrates, and an electric field is applied between the two electrodes to move the liquid crystal molecules by the electric field to transmit light. It is a device for displaying an image by differently.

The liquid crystal display device is separated and used in various modes according to the arrangement of the liquid crystal molecules. Liquid crystal display using vertical switching modes, such as vertically aligned (VA) mode, electrically controlled Birefringence (ECB) mode, and twisted nematic (TN) mode. We are trying to widen your viewing angle. However, in the vertical switching mode, color shift phenomenon and gray correction problem occur in the gray scale region when the liquid crystal display is driven. Of course, recently, active researches have been conducted to minimize the color change and easily perform the gray correction by changing the optical design of the liquid crystal panel or driving conversion to solve the color change. However, in the case of the existing optical design change and the drive conversion, some color change can be reduced, but the luminance of the entire panel is reduced.

Accordingly, the present invention is derived to solve the above problems, and can be driven by each of the gray, R, G, B for each gray to facilitate color coordinate adjustment and to improve the brightness voltage generation module and It is an object of the present invention to provide a liquid crystal display and a driving method thereof.

At least one liquid crystal for generating liquid crystal driving voltages having different voltage levels according to the R, G, and B data, and a first voltage input terminal to which a liquid crystal driving voltage is input, a second voltage input terminal to which a ground power source is input, and R, G, and B data according to the present invention. A gray voltage generation module including a driving voltage converting unit and gray level voltage generating means for generating different gray level voltages according to liquid crystal driving voltages having different voltage levels.

Here, the liquid crystal driving voltage converter and the gray voltage generator are connected in series between the first and second voltage input terminals, and between the gray voltage generator and the first voltage input terminal, and between the gray voltage generator and the gray voltage generator. It is preferable that the said liquid crystal drive voltage conversion part is connected between at least any one of 2 voltage input terminals. Of course, the gradation voltage generating means may effectively include a first gradation voltage generating means for generating a positive gradation voltage and a second gradation voltage generating means for generating a negative gradation voltage.

It is effective that the liquid crystal drive voltage converter includes at least one switching member operating in accordance with the R, G, and B data signals, and a plurality of voltage distribution members connected to the switching member. In this case, it is effective to use at least one of a resistor, a diode, and a transistor including a variable resistor as the voltage distribution member. The liquid crystal driving voltage converter includes first to third switching members that operate according to the R, G, and B data signals, and first to third voltage distribution members that are respectively connected thereto. It is effective to adjust the voltage division values of the first to third voltage distribution members so that the liquid crystal driving voltages of the different voltage levels are changed within a range of 1 to 40% of. Of course, the liquid crystal driving voltage conversion unit generates liquid crystal driving voltages of first to third voltage levels according to the R, G, and B data signals, and the gray scale voltage generating means drives the liquid crystal of the first to third voltage levels. It is preferable to generate the gradation voltages of the first to third voltage levels according to the voltage.

In addition, a liquid crystal display panel including a liquid crystal display panel having R, G, and B pixels according to the present invention for displaying an image, and a gray voltage generation module for supplying different gray voltages to each of the R, G, and B pixels. to provide.

Here, the gray voltage generation module generates a liquid crystal driving voltage having a different voltage level according to R, G, and B data, and a first voltage input terminal to which a liquid crystal driving voltage is input, a second voltage input terminal to which ground power is input, and R, G, and B data. It is preferable to include at least one liquid crystal driving voltage converting unit and gray scale voltage generating means for generating different gray scale voltages according to the liquid crystal driving voltages of different voltage levels.

It is preferable that the liquid crystal driving voltage converter includes at least one switching member operating in accordance with R, G, and B data signals, and a plurality of voltage distribution members connected to the switching member.

Of course, the liquid crystal driving voltage conversion unit generates liquid crystal driving voltages of first to third voltage levels according to the R, G, and B data signals, and the gray scale voltage generating means drives the liquid crystal of the first to third voltage levels. It is effective to generate the gradation voltages of the first to third voltage levels in accordance with the voltage.

And a signal controller configured to supply the R, G, and B data signals to the gray voltage generator so that the image data is applied to supply the gray voltages having different voltage levels to each of the R, G, and B pixels. It is preferable.

Of course, it may further include a driving voltage generator for supplying the liquid crystal driving voltage.

In addition, a liquid crystal driving voltage is generated by varying the level of the liquid crystal driving voltage through the step of applying the liquid crystal driving voltage according to the present invention, and generating a liquid crystal driving voltage by the R, G, and B data signals. Generating a liquid crystal drive distribution voltage of different levels by adjusting the voltage distribution, and generating a gray voltage of different levels by voltage-dividing the liquid crystal drive distribution voltages of different levels.

The generating of the liquid crystal driving voltages having different levels may include: generating a liquid crystal driving voltage having a first voltage level by dividing the liquid crystal driving voltages according to an R data signal and generating a liquid crystal driving voltage having a first voltage level; Dividing the liquid crystal driving voltage by a second voltage to generate a liquid crystal driving voltage having a second voltage level; and dividing the liquid crystal driving voltage by a third voltage according to a B data signal to obtain a liquid crystal driving voltage having a third voltage level. It is preferred to include the step of producing.

In addition, the liquid crystal display panel including a liquid crystal display panel having an R, G, B pixels according to the present invention for displaying an image, and a gray voltage generation module for supplying different gray voltages to each of the R, G, and B pixels. A driving method comprising sequentially activating the R, G, and B pixels, and supplying different gray voltages to the activated R, G, and B pixels according to R, G, and B data signals. A driving method of a liquid crystal display device is provided.

Here, supplying different gray voltages to the activated R, G, and B pixels according to the R, G, and B data signals includes supplying a liquid crystal driving voltage to the gray voltage generation module, and R data signal. The liquid crystal driving voltage is divided into a first voltage to generate a liquid crystal driving voltage distribution having a first voltage level, and the liquid crystal driving voltage distribution of the first voltage level is divided into voltage to generate a gray scale voltage having a first voltage level. Supplying a gray voltage of the first voltage level to the R pixel, and dividing the liquid crystal driving voltage by a second voltage according to a G data signal to generate a liquid crystal driving divided voltage of a second voltage level, wherein the second voltage is generated. Supplying a gray voltage of the second voltage level to the G pixel by generating a gray voltage of a second voltage level by voltage-dividing the liquid crystal driving voltage of the level; The liquid crystal driving voltage is divided by a third voltage to generate a liquid crystal driving voltage of a third voltage level. The liquid crystal driving voltage of the third voltage level is divided by voltage to generate a gray voltage of a third voltage level. It is preferable to include the step of supplying the gray voltage of the second voltage level to the B pixel.

Hereinafter, with reference to the accompanying drawings will be described an embodiment of the present invention in more detail. However, the present invention is not limited to the embodiments disclosed below, but will be implemented in various forms, and only the embodiments are intended to complete the disclosure of the present invention, and to those skilled in the art to fully understand the scope of the invention. It is provided to inform you.

1 is a block diagram of a liquid crystal display according to an exemplary embodiment of the present invention, and FIG. 2 is a block diagram of a data driver according to an exemplary embodiment.

1 and 2, the liquid crystal display according to the present exemplary embodiment includes a thin film transistor T and a liquid crystal capacitor Clc connected to a plurality of crossing gate lines G1 to Gn and data lines D1 to Dm. And a liquid crystal display panel 100 for displaying an image including a sustain capacitor Cst, a gate driver 200 connected to the gate lines G1 to Gn to control an operation of the thin film transistor T, A data driver 300 connected to the data lines D1 to Dm to control a gray voltage applied to the liquid crystal capacitor Clc and the storage capacitor Cst through the thin film transistor T, and an external control signal ( A signal controller 400 for controlling the gate driver 200 and the data driver 300 through R, G, B, DE, Hsync, Vsync, and CLK, and a gate driver according to a signal of the signal controller 400 Driving voltages Von, Voff, and A of the 200 and the data driver 300. And a driving voltage generator 500 for generating VDD.

The liquid crystal display panel 100 includes a plurality of gate lines G1 to Gn extending in a substantially column direction and a plurality of data lines D1 to Dm extending in a row direction perpendicular thereto, and the gate line G1. To Gn) and a pixel area defined at an intersection area of the data lines D1 to Dm. A pixel including the thin film transistor T, the storage capacitor Cst, and the liquid crystal capacitor Clc is provided in the pixel area. The pixel may include red (R), green (G), and blue (B) pixels, and may display a total natural color through a combination thereof. The liquid crystal display panel 100 includes a thin film transistor substrate (not shown) including a thin film transistor T, a gate line G1 to Gn, a source line D1 to Dm, and a pixel electrode for a liquid crystal capacitor, a black matrix, and a color. A common electrode substrate (not shown) provided with a common electrode for a filter and a liquid crystal capacitor, and a liquid crystal layer (not shown) provided between the thin film transistor substrate and the common electrode substrate.

In the liquid crystal display panel 100, when the gate-on voltage Von is applied by the gate driver 200, the thin film transistor T is turned on. Thereafter, when the gray voltage is applied by the data driver 300, the gray voltage is applied to the liquid crystal capacitor Clc through the turned-on thin film transistor T to change the electric field across the liquid crystal capacitor Clc. Due to the electric field change, the arrangement of the liquid crystals provided between the liquid crystal capacitors Clc is changed, and the light transmittance from the backlight provided at the lower side of the liquid crystal display panel 100 is adjusted due to the change in the liquid crystal arrangement to adjust the target image. Display. In this case, the liquid crystal display panel 100 preferably includes a color filter of red (R), green (G), or blue (B) to correspond to the pixel electrode in order to display various colors.

The above-described signal controller 400 is an input image signal from an external graphic controller (not shown), that is, an input control signal for controlling pixel data R, G, and B and its display, for example, a vertical synchronization signal ( Vsync), a horizontal sync signal (Hsync), a main clock (CLK), and a data enable signal (DE). The pixel data is processed according to operating conditions of the liquid crystal display panel 100, a gate control signal and a data control signal are generated, and the gate control signal is transmitted to the gate driver 200. Here, the pixel data is rearranged according to the pixel arrangement of the liquid crystal display panel 100. The gate control signal includes a vertical synchronization start signal STV, a gate clock signal CPV, an output enable signal OE, and the like that indicate the start of output of the gate-on voltage Von. The data control signal includes a synchronization start signal STH indicating the start of transmission of pixel data, a load signal TP for applying a data voltage to a corresponding data line, and an inversion signal for inverting the polarity of the gray voltage with respect to the common voltage Vcom ( RVS) and data clock signal CLK.

The driving voltage generator 500 receives the control signal from the signal controller 400 and applies the gate-on voltage Von and the gate-off voltage Voff to the gate driver 200, and the gray level for driving the liquid crystal device. The liquid crystal driving voltage as a reference of the voltage is generated and applied to the data driver 300.

The gate driver 200 applies the gate on / off voltages Von / Voff of the driving voltage generator 500 to the gate lines G1 to Gn according to an external control signal. Accordingly, the thin film transistor T may be controlled to apply the gray voltage to each pixel.

The data driver 300 generates a gray voltage using the control signal of the signal controller 400 and the liquid crystal driving voltage of the driving voltage generator 500, and applies the gray voltage to each data line D1 to Dm.

As illustrated in FIG. 2, the data driver 300 samples the pixel data through the shift register unit 310 sequentially transmitting the sampling signal, the data register unit 320 temporarily storing the pixel data, and the sampling signal. A latch unit 330 for latching, a gray voltage generator 600 for generating a plurality of gray voltages, a digital to analog converter (DAC) 340 for converting the latched pixel data into a gray voltage; The buffer unit 350 supplies the converted pixel data to the data lines D1 to Dm.

The shift register unit 310 generates a sequential sampling signal using a signal such as a data sampling clock (DSC) received from the signal controller 400 and supplies it to the latch unit 330. The latch unit 330 samples and latches pixel data temporarily stored in the data register unit 320 in response to the sampling signal of the shift register unit 310. In this case, the latch unit 330 simultaneously latches and outputs pixel data corresponding to each of the data lines D1 to Dm. The gray voltage generator 600 outputs a plurality of reference voltages using the liquid crystal driving voltage AVDD, and outputs a plurality of gray voltages using the plurality of reference voltages. The DAC unit 340 converts the pixel data output from the latch unit 330 into a gray voltage output from the gray voltage generator 600 and outputs the gray data. The buffer unit 350 receives a gray voltage output from the DAC unit 340, samples and holds the gray voltage and outputs the gray voltage.

In the above description, the gray voltage generator 600 is provided in the data driver 300, but the present invention is not limited thereto. The gray voltage generator 600 may be provided as a separate module outside the data driver 300. It may be arranged.

The gray voltage generator 600 changes the level of the gray voltage generated by changing the reference level of the liquid crystal driving voltage VADD according to the pixel data. That is, the gray voltage generator 600 according to the present exemplary embodiment generates gray voltages having different voltage levels according to the pixel data applied, that is, the R, G, and B data, and is different from each of the R, G and B pixels. The gray scale voltage can be applied, so that color coordinate adjustment and luminance can be improved.

3 is a circuit diagram of a gray voltage generator according to a first embodiment of the present invention.

Referring to FIG. 3, the gray voltage generator 600 may include liquid crystal driving voltage converters 610, 620, 630, and 640 that set different liquid crystal driving voltages AVDD according to R, G, and B data. Gray voltage generation means 650 and 660 for generating gray voltages VINP0 + to VINP7 + and VINP0- to VINP7- according to different liquid crystal driving voltages AVDD.

The above-described liquid crystal driving voltage converters 610, 620, 630, and 640 may be connected to the first external voltage AVDD and may include first and second voltage converters having different resistance values according to R, G, and B data. 610 and 620, and third and fourth voltage converters 630 and 640 connected to the second external voltage VSS and having different resistance values according to R, G, and B data.

The first external voltage AVDD refers to a liquid crystal driving voltage, and the second external voltage VSS refers to a ground voltage. Positive grayscale voltages VINP0 + to VINP7 + are generated through the liquid crystal driving voltages changed by the first voltage converter 610 and the third voltage converter 630, and the second voltage converter 620. Negative gray voltages VINP0- to VINP7- may be generated through the fourth voltage converter 640. When only the positive gray voltage is used, the second and fourth voltage converters may be omitted.

Each of the first and second voltage converters 610 and 620 includes a plurality of resistor members R1 -R, R2-G, and R3-B connected to a first external voltage input terminal, and the resistor members R1 -1. Switching members (S1-R, S2-G, S3-B) respectively provided between R, R2-G, R3-B and gradation voltage generating means (650, 660) to drive according to the R, G, and B data. It includes. As shown in the drawing, one end of the first to third resistance members R1-R, R2-G, and R3-B is connected to the first external voltage input terminal, and the other end of the first to third switching members, respectively. It is connected to one end of (S1-R, S2-G, S3-B). The other ends of the first to third switching members S1-R, S2-G, and S3-B are connected to the gradation voltage generating means 650, 660, and are respectively controlled by the R, G, and B data.

Each of the third and fourth voltage change units 630 and 640 is connected to the fourth to sixth resistor members R4-R, R5-G, and R6-B connected to the second external voltage input terminal, respectively. And fourth to sixth switching members S4-R, S5-G, and S6-B, and the other end of the switching members S4-R, S5-G, and S6-B includes the gray voltage generator. 630 and 640, each of which is controlled by R, G, and B data, respectively. Here, the first to sixth resistance members (R1-R, R2-G, R3-B, R4-R, R5-G, R6-B) preferably use resistors having different resistance values. In this embodiment, it is effective to use a variable resistor as the resistance member.

The above-described gray voltage generator 650 and 660 includes a positive gray voltage generator 650 for generating a positive gray voltage and a negative gray voltage generator 660 for generating a negative gray voltage. Each of the positive and negative voltage generating means 650 or 660 generates the first to eighth gray voltages VINP0 + to VINP7 + and VINP0- to VINP7- having different voltage levels. The positive and negative gray voltage generators 650 and 660 may include first and second nodes Q1 and Q2 for generating first and eighth gray voltages VINPO +, VINP7 +, VINP0-, and VINP7-. First to sixth voltage generation stages 651 to 656 and 661 connected between the first and second nodes Q1 and Q2 to generate second to seventh gray voltages VINP1 + to VINP6 + and VINP1- to VINP6-. To 666). The first node Q1 of the constant gray voltage generating means 650 is connected to the first voltage converter 610, and the second node Q2 is connected to the third voltage converter 630. The first node Q1 of the sub gray level voltage generator 660 is connected to the second voltage converter 620, and the second node Q2 is connected to the fourth voltage converter 640. The first to sixth voltage generation stages 651 to 656 and 661 to 666 are connected to the first to sixth line resistors RL1 to RL6 connected in parallel between the first and second nodes Q1 and Q2, respectively. First to sixth multiplexer units 651-1 to 656-1 and 661-1 to 666 outputting one of the selection voltages according to the total distribution of the line resistors as grayscale voltages according to the selection signals SEL0 to SEL7. -1). Each of the multiplex parts preferably uses an 8-to-1 multiplexer.

This will be described in more detail with reference to the drawings. In the following description, the gray scale voltage generating means 650 will be described.

The first node Q1 is connected to the first voltage converter 610 and outputs a first gray voltage VINP0 +. The first line resistor RL1 of the first voltage generator 651 is connected between the first node Q1 and the second line resistor RL2 of the second voltage generator 652. The input terminal of the first multiplexer 651-1 of the first voltage generator 651 is connected to different points of the first line resistor RL1 and is within a voltage range across the first line resistor RL1. The first to eighth selection voltages VP1 to VP8 which are different from each other are received. The voltage of any one of the first through eighth selection voltages VP1 through VP8 is output as the second gray voltage VINP1 + according to the first selection signal SEL0. The second to sixth voltage generation stages 652, 653, 654, 655, and 656 are selected within the voltage range across the corresponding line resistors RL2 to RL6, similarly to the first voltage generation stage 651. The gray level voltage selected according to the signal is output. The second node Q2 is connected to the third voltage converter 630 to output the eighth gray voltage VINP7 +.

Hereinafter, the operation of the gray voltage generator according to the embodiment of the above-described structure will be described.

The gray voltage generator 600 generates gray voltages VINP0 + to VINP7 + and VINP0- to VINP7- having different voltage levels according to the R, G, and B data signals. To this end, the gray level provided between the first and second external voltages AVDD and VSS is changed by changing resistance values of the first to fourth voltage converters 610, 620, 630, and 640 according to the R, G, and B data signals. The voltage levels of the gray voltages VINP0 + to VINP7 + and VINP0- to VINP7- may be adjusted by changing the reference voltages across the voltage generating means 650 and 660.

As described above, according to the present embodiment, the maximum luminance of each pixel can be obtained by applying different levels of gradation voltages to the R, G, and B pixels according to the R, G, and B data signals. Because it accurately represents its own color, phenomena such as color change can be improved, and color coordinates can be easily adjusted by adjusting the resistance value.

4 is a graph illustrating luminance of R, G, and B pixels according to an applied gray voltage.

4 is a graph showing luminance variation of R, G, and B pixels according to gray voltage in a VA mode having a cell gap of 5 μm. The maximum luminance is shown at 4.5 V for R pixels and 3.5 for G pixels. The maximum luminance is shown at V, and the maximum luminance is displayed at 3.0 V for the B pixel. Therefore, if the same gradation voltage is applied to the R, G, and B pixels, it can be seen that the luminance decreases greatly according to the pixel. For example, when trying to express white by applying a 3.0V gray voltage, the B pixel emits light at its maximum brightness, but the luminance decreases through the remaining R and G pixels. Accordingly, when the gray scale voltages having different voltage levels are applied to the R, G, and B pixels, the maximum luminance can be secured. That is, for example, when expressing white based on a 3.5 V gray voltage, a 3.5 V gray voltage is applied to the G pixel as it is, and a 4.5 V gray voltage is applied to the R pixel by changing the level of the gray voltage. The gray level voltage is also changed to the B pixel to apply a 3.0 V gray voltage to obtain white light having the maximum luminance.

Accordingly, the gray voltage generator of the present embodiment receives the R, G, and B data signals to generate gray voltages having different voltage levels, and transmit the gray voltages to the R, G, and B pixels through the data driver. As a result, the luminance can be improved, the color coordinates of each gray level can be easily adjusted, and the B pixel can prevent the brightness from being reversed due to voltage, thereby improving the viewing angle and gray inversion.

To this end, the gray voltage generator 600 may include voltage converters 610, 620, 630, and 640 having different resistance values according to R, G, and B data signals, at both ends of the gray voltage generator 650, 660. The voltage level of the gray scale voltages VINP0 + to VINP7 + and VINP0- to VINP7- can be adjusted.

This will be described with reference to the drawings.

5 is a conceptual diagram illustrating a voltage adjusting method according to an embodiment of the present invention.

As shown in FIG. 5, when the first external voltage AVDD is a voltage of 10 V, when there is no voltage converter 610, 620, 630, or 640 of the present embodiment, the gray voltage generator 650 or 660. ), Both voltages of 10V are applied, and gray scale voltages (VINP0 + to VINP7 +, VINP0- to VINP7-) are generated within the range of 10V. However, when the resistance of 1 ohm is disposed on both sides of the gray voltage generating means 650 or 660, a voltage of about 8.3V is applied to the hem of the gray voltage generating means 650 or 660, so that it is 8.3V. The gray scale voltages VINP0 + to VINP7 + and VINP0- to VINP7- are generated within the range of.

As described above, in the present exemplary embodiment, the resistance values located at both ends of the gray voltage generator 650 or 660 are changed in accordance with the R, G, and B data signals to adjust the range of voltages therebetween.

When the R data signal is applied, the first switching members S1 -R connected to the first resistance members R1-R of the first and second voltage converters 610, 620 are turned on, and the third and fourth parts are connected. The fourth switching member S4-R connected to the fourth resistance member R4-R of the voltage converters 630 and 640 is conductive. As a result, the first resistor member R1-R, the first through sixth wire resistors RL1 through RL6, and the fourth resistor member R4-R are connected in series between the first and second external voltages AVDD and VSS. The first and second external voltages AVDD and VSS are voltage-divided by each of them, and are output as first through eighth gray voltages VINP0 + to VINP7 + and VINP0- to VINP7- of the first voltage level. When the G data signal is applied, the second switching member S2-G connected to the second resistance member R2-G of the first and second voltage converters 610 and 620 is turned on, and the third and third The fifth switching member S5-G connected to the fifth resistance member R5-G of the four voltage converters 630 and 640 is turned on. As a result, the second resistor member R2-G, the first to sixth wire resistors RL1 to RL6 and the fifth resistor member R5-G are connected in series between the first and second external voltages AVDD and VSS. The first and second external voltages AVDD and VSS are voltage-divided by them, and are output as the first to eighth gray voltages VINP0 + to VINP7 + and VINP0- to VINP7- of the second voltage level. When the B data signal is applied, the third switching member S3-B connected to the third resistance member R3-B of the first and second voltage converters 610 and 620 is turned on, and the third and fourth The sixth switching member S6-B connected to the sixth resistance member R6-B of the voltage converters 630 and 640 is turned on. As a result, the third resistor member R3-B, the first to sixth wire resistors RL1 to RL6 and the sixth resistor member R6-B are connected in series between the first and second external voltages AVDD and VSS. The first and second external voltages AVDD and VSS are voltage-divided by them, and are output as the first to eighth gray voltages VINP0 + to VINP7 + and VINP0- to VINP7- of the third voltage level.

It is preferable that the voltage change range of the gradation voltages of the first to third voltage levels is 1 to 50% of the liquid crystal voltage. For example, when the highest gray level voltage is 10V, the highest gray level voltage may be changed within a range of 6.0V to 9.9V. It is more preferable to be able to be adjusted in the range (1 to 20%) within 20% of the liquid crystal voltage. Since the driving voltage varies according to the mode of the liquid crystal used in the liquid crystal display panel, it is effective to variously adjust the resistance values in the first to fourth voltage converters accordingly.

In the present embodiment, when the resistance in the first to fourth power conversion units uses a variable resistor, color correction may be facilitated by changing the resistance value based on an image displayed on the liquid crystal display panel.

FIG. 6 is a graph illustrating voltages for gray levels applied to R, G, and B pixels through the gray voltage generator according to the present invention.

As shown in FIG. 6, in the present embodiment, different voltage values may be applied for each gray level, and luminance may be increased through color correction. In addition, the difference of color coordinates can be correct | amended above intermediate gray. In addition, the white color coordinates can be easily adjusted to the desired value.

The present embodiment is not limited to the above description, and the voltage converter may be connected in various forms, and a separate voltage distribution member may be used instead of the resistance and the line resistance in the voltage changer.

Hereinafter, various modifications according to the present embodiment will be described. In the description of the modifications described below, the description overlapping with the above description will be omitted.

7 is a circuit diagram of a gray voltage generator according to a first modification of the present embodiment.

As shown in FIG. 7, the gray voltage generator according to the present modified example may arrange the voltage converters 610 and 640 on at least one side of the upper and lower sides of the gray voltage generators 650 and 660. That is, the voltage converter 610 is provided between the first external voltage AVDD and the positive gray voltage generating means 650, and a separate resistor member R630 is provided to the positive gray voltage generating means 650 and the second external. The voltage level of the grayscale voltages VINP0 + to VINPn + output by the grayscale voltage generating means 650 may be adjusted according to the R, G, and B data signals provided between the voltages VSS. The other voltage converter 640 is provided between the second external voltage VSS and the sub-gradation voltage generating means 660, and a separate resistor member R620 is provided between the first external voltage AVDD and the sub-gradation voltage. The voltage level of the grayscale voltages VINP0- to VINPn- output by the sub-gradation voltage generating means 660 may be adjusted between the generating means 660 and the sub-gradation voltage generating means 660 according to the R, G, and B data signals.

The positive and negative gray voltage generators 650 and 660 may be provided with a plurality of voltage generators 651 and 661 to generate a plurality of gray voltages VINP0 + to VINPn + and VINP0- to VINPn−.

8 is a circuit diagram of a gray voltage generator according to a second modified example of the present embodiment.

As shown in FIG. 8, the gray voltage generator 600 according to the present modification uses a voltage distribution member capable of voltage distribution instead of a resistor or a line resistance.

The first and second voltage converters 610 and 620 may include first to third voltage distribution members 611R, 612G, 613B, 621R, 622G, and 623B respectively connected to first external voltage input terminals. First to third switching members S1-R, S2-G connected between the three voltage distribution members 611R, 612G, 613B, 621R, 622G, 623B and the first node of the gray voltage generator 650, 660. , S3-B). The third and fourth voltage converters 630 and 640 respectively include fourth to sixth voltage distribution members 631R, 632G, 633B, 641R, 642G, and 643B connected to second external voltage input terminals, respectively. Sixth to sixth switching members S4-R, S5-G, and S6-B connected between the voltage distribution members 631R, 632G, 633B, 641R, 642G, and 643B and the second node of the gradation voltage generating means. It includes.

In this modification, not only the resistors described in the above embodiments but also transistors or diodes can be used as the voltage distribution members. In addition, it is effective to use a transistor as the switching member.

Each of the plurality of voltage generating stages 651, 661 in the positive and negative gray voltage generating means 650, 660 is a plurality of voltage distribution members 652-1, 652-2, 652-3, instead of the line resistance of the foregoing embodiment. Voltage distribution means connected in series with 652-4, 652-5, 652-6, 652-7, 652-8, and 652-9 may be used. Therefore, the distribution voltage at the series connection ends of the voltage distribution members 652-1, 652-2, 652-3, 652-4, 652-5, 652-6, 652-7, 652-8, 652-9. The grayscale voltage may be generated and transmitted to the multiplexer 651-1, and a plurality of gray voltages may be generated through the selection signal SEL0.

As described above, the gradation voltage generating means of the present embodiment may be switched according to each of the R, G, and B data signals to supply the levels of the gradation voltages differently according to the R, G, and B to improve color coordinate adjustment and brightness.

As described above, the present invention can easily perform color adjustment by applying gray voltages having different voltage levels to each of the R, G, and B pixels and driving them.

In addition, the luminance can be improved by applying a voltage having a level capable of exhibiting the maximum luminance to each of R, G, and B for each gray.

In addition, the setting of the color coordinates for each gradation becomes easy, and it can be easily adjusted to match the numerical value for which the white color coordinates are targeted.

In addition, the phenomenon in which the blue pixel is reversed in brightness due to voltage can be prevented, thereby improving viewing angle, gray inversion, and the like.

Although the invention has been described with reference to the accompanying drawings and the preferred embodiments described above, the invention is not limited thereto, but is defined by the claims that follow. Accordingly, one of ordinary skill in the art may variously modify and modify the present invention without departing from the spirit of the following claims.

Claims (17)

A first voltage input terminal to which a liquid crystal driving voltage is input; A second voltage input terminal to which a ground power source is input; At least one liquid crystal driving voltage converter configured to generate liquid crystal driving voltages having different voltage levels according to R, G, and B data; And a gray voltage generator for generating different gray voltages according to the liquid crystal driving voltages of different voltage levels. The method according to claim 1, The liquid crystal driving voltage converter and the gray voltage generator are connected in series between the first and second voltage input terminals, and between the gray voltage generator and the first voltage input terminal, and between the gray voltage generator and the second voltage. The gray voltage generation module to which the liquid crystal driving voltage converter is connected between at least one of input terminals. The method according to claim 2, The gray voltage generating means includes a first gray voltage generating means for generating a positive gray voltage and a second gray voltage generating means for generating a negative gray voltage. The method according to any one of claims 1 to 3, And the liquid crystal driving voltage converter comprises at least one switching member operating according to R, G, and B data signals, and a plurality of voltage distribution members connected to the switching member. The method according to claim 4, And the voltage distribution member uses at least one of a resistance member including a variable resistor, a diode, and a transistor. The method according to claim 4, The liquid crystal driving voltage converter includes first to third switching members operating according to the R, G, and B data signals, and first to third voltage distribution members respectively connected thereto. And a gray voltage generation module for adjusting the voltage division values of the first to third voltage distribution members so that the liquid crystal driving voltages of the different voltage levels are changed within the range of 1 to 40% of the liquid crystal driving voltage. The method according to claim 4, The liquid crystal driving voltage converter generates liquid crystal driving voltages of first to third voltage levels, respectively, according to the R, G, and B data signals, and the gray scale voltage generating means generates liquid crystal driving voltages of the first to third voltage levels. And a gray voltage generator for generating gray voltages having the first to third voltage levels. A liquid crystal display panel having R, G, and B pixels and displaying an image; And a gray voltage generator module for supplying different gray voltages to each of the R, G, and B pixels. The method according to claim 8, The gray scale voltage generation module may include at least one of a first voltage input terminal to which a liquid crystal driving voltage is input, a second voltage input terminal to which a ground power source is input, and at least one liquid crystal driving voltage having different voltage levels according to R, G, and B data And a gray voltage generator for generating different gray voltages according to the liquid crystal driving voltages of different voltage levels. The method according to claim 9, And the liquid crystal driving voltage converter includes at least one switching member operating according to R, G, and B data signals, and a plurality of voltage distribution members connected to the switching member. The method according to claim 9, The liquid crystal driving voltage converter generates liquid crystal driving voltages of first to third voltage levels, respectively, according to the R, G, and B data signals, and the gray scale voltage generating means generates liquid crystal driving voltages of the first to third voltage levels. And a gray voltage of the first to third voltage levels. The method according to claim 8, And a signal controller configured to supply the R, G, and B data signals to the gray voltage generator so that image data is supplied to each of the R, G, and B pixels to supply gray voltages having different voltage levels. . The method according to claim 8, And a driving voltage generator configured to supply the liquid crystal driving voltage. Receiving a liquid crystal driving voltage; Generating a liquid crystal driving voltage by changing the level of the liquid crystal driving voltage through voltage division, and generating a liquid crystal driving voltage having different levels by adjusting the magnitude of the voltage division according to R, G, and B data signals. ; And a gray level voltage having different levels by dividing the liquid crystal driving voltages of the different levels. The method of claim 14, wherein the generating of the liquid crystal drive voltages having different levels comprises: Generating a liquid crystal drive divided voltage having a first voltage level by dividing the liquid crystal drive voltage according to an R data signal; Generating a liquid crystal drive divided voltage having a second voltage level by dividing the liquid crystal drive voltage according to a G data signal; And a third voltage division of the liquid crystal driving voltage according to the B data signal to generate a liquid crystal driving division voltage of a third voltage level. In the driving method of a liquid crystal display device comprising a liquid crystal display panel having an R, G, B pixels to display an image, and a gray voltage generator module for supplying different gray voltages to each of the R, G, and B pixels, Sequentially activating the R, G, and B pixels; And supplying different gray voltages to the activated R, G, and B pixels according to R, G, and B data signals. The method of claim 16, wherein supplying different gray voltages to the activated R, G, and B pixels according to the R, G, and B data signals comprises: Supplying a liquid crystal driving voltage to the gray voltage generation module; The liquid crystal driving voltage of the first voltage level is generated by dividing the liquid crystal driving voltage by a first voltage according to an R data signal, and the gray level voltage of the first voltage level is obtained by voltage dividing the liquid crystal driving voltage of the first voltage level. Generating and supplying a gray voltage of the first voltage level to the R pixel; The liquid crystal driving voltage of the second voltage level is generated by dividing the liquid crystal driving voltage by a second voltage according to a G data signal, and the gray level voltage of the second voltage level is obtained by voltage dividing the liquid crystal driving voltage of the second voltage level. Generating and supplying a gray voltage of the second voltage level to the G pixel; The liquid crystal driving voltage of the third voltage level may be generated by dividing the liquid crystal driving voltage by a third voltage according to a B data signal, and the gray level voltage of the third voltage level may be obtained by dividing the liquid crystal driving voltage of the third voltage level. Generating and supplying a gray voltage of the second voltage level to the B pixel.

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