KR100963799B1 - generating apparatus of gamma voltage of LCD and method thereof - Google Patents

Abstract

A gamma voltage generator of a liquid crystal display according to the present invention includes a first, second, and third divided circuit section for dividing a voltage applied from the outside into a plurality of levels, and a plurality of outputs by the first, second, and third divided circuit sections. First, second, and third amplifiers for amplifying the voltages of the levels, and a data driving circuit to which the signal output from the amplifier is input, and the first, second, and third voltage divider circuits each include a plurality of resistors. The external input voltages having different magnitudes are respectively supplied to the first, second, and third voltage divider circuits by adjusting the magnitudes of the external input voltages applied to the first, second, and third voltage divider circuits. Each of the three voltage divider circuits generates a plurality of levels of gamma voltages so as to correspond to data corresponding to red (R), green (G), and blue (B), respectively, and generates a plurality of levels of gamma voltages output from the first, second, and third voltage divider circuits. The gamma voltage depends on the corresponding color (R, G, B) The size may be applied differently.

According to the present invention, by providing gamma voltages individually for the data corresponding to red (R), green (G), and blue (B), fine tuning for each of the colors of R, G, and B is possible. In addition, there is an advantage in that the control of the color factors and color coordinates for R, G, and B can be circuitically enabled.

Description

Gamma voltage generating device and method thereof of liquid crystal display device

1 is an exploded perspective view showing a part of a general liquid crystal display device.

2 is a block diagram showing a conventional active matrix liquid crystal display device.

3 is a characteristic diagram illustrating a gamma voltage generated from the gamma voltage generator shown in FIG. 2.

Figure 4 is a schematic diagram showing a conventional gamma voltage generator.

5 is a configuration diagram briefly showing a gamma voltage generator according to the present invention.

Fig. 6 is a characteristic diagram showing each of the multilevel gamma voltages generated from the gamma voltage generator according to the present invention.

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

500: gamma voltage generator 510: first voltage divider

512: first amplifier 520: second voltage divider circuit

522: second amplifier 530: third voltage divider circuit

532: third amplifier 540: data driving circuit

542: first decoder unit 544: second decoder unit

546: third decoder unit

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device, and more particularly, to a gamma voltage generator and a method thereof for providing a gamma voltage for red, green, and blue data, respectively.

Recently, a liquid crystal display (LCD) has been widely used as a device for displaying various images including still and moving images, which is characterized by light weight, thin film, low power consumption, and improved liquid crystal materials and fine pixels. Image quality is being accelerated by the development of processing technology, and its application range is gradually increasing.

In the liquid crystal display (LCD), each pixel is generally arranged in a matrix form on a liquid crystal panel constituting a screen of the display device, and each pixel is formed with a thin film transistor as a switching element. In addition, a gate line and a data line passing through the thin film transistor are provided.

Such a liquid crystal display device is called an active matrix liquid crystal display device, and the active matrix liquid crystal display device displays an image by adjusting the light transmittance of the liquid crystal by an electric field applied to the liquid crystal.

1 is an exploded perspective view showing a part of a general liquid crystal display device.                         

Referring to FIG. 1, a general liquid crystal display device includes a color filter 7 including a black matrix 6, a sub color filter (red (R), green (G), and blue (B)) 8, and a color filter. An upper substrate 5 having a transparent common electrode 18 formed thereon, and a lower substrate 22 having an array wiring including a pixel region P and a pixel electrode 17 and a switching element T formed on the pixel region. The liquid crystal 14 described above is filled between the upper substrate 5 and the lower substrate 22.

The lower substrate 22 is also referred to as an array substrate, and the thin film transistor T, which is a switching element, is disposed in a matrix form, and a gate line 13 and a data line 15 passing through the plurality of thin film transistors are formed.

In addition, the pixel electrode 17 formed on the pixel region P uses a transparent conductive metal having a relatively high transmittance of light, such as indium tin oxide (ITO).

In the liquid crystal display device 11 configured as described above, the liquid crystal layer 14 positioned on the pixel electrode 17 is oriented by a signal applied from the thin film transistor, and the liquid crystal layer depends on the degree of alignment of the liquid crystal layer. The image can be expressed by controlling the amount of light passing through the image.

Here, the light passing through the red (R) sub filter is displayed in red, the light passing through the green (G) sub filter is displayed in green, and the light passing through the blue (R) sub filter is displayed in red. The mixture of these three primary colors will be able to express a variety of light.                         

2 is a block diagram showing a conventional active matrix liquid crystal display device.

Referring to FIG. 2, a liquid crystal panel 2 in which liquid crystal cells are arranged in a matrix between two transparent substrates, and a gate driving circuit 4 connected to gate lines GL1 to GLm of the liquid crystal panel 2. And a data driver circuit 4 connected to the data lines DL1 to DLn of the liquid crystal panel 2 and a gamma voltage generator 3 connected to the data driver circuit 4.

A thin film transistor (hereinafter referred to as TFT) is provided as a switching element at an intersection of the m gate lines GL1 to GLm and the n data lines DL1 to DLn. The furnace 4 'sequentially supplies the scanning signals to the m gate lines GL1 to GLm to drive the TFTs connected to the corresponding gate lines.

In addition, the gamma voltage generator 3 supplies a preset DC voltage to the data lines DL1 to DLn as a gamma voltage Vγ so as to have different levels for each luminance as shown in FIG. 3. The gamma voltage Vγ is a DC voltage having a voltage level equivalent to that of the high potential supply power supply VDD corresponding to the highest luminance value according to the luminance value of the video data, and a DC voltage having a lower voltage level as the luminance value decreases. Vn to V0) are selected.

Since the liquid crystal used in the liquid crystal display uses electro-optical characteristics, the optical modulation rate and the voltage level of the image signal have a non-linear relationship, and also depend on the spectral characteristics of the liquid crystal and the like. Since each nonlinearity differs for each primary color, gamma adjustment is necessary to preliminarily correct the nonlinearity, and the gamma voltage generator is provided for such gamma adjustment.

4 is a configuration diagram schematically showing a conventional gamma voltage generator.

Referring to FIG. 4, a plurality of resistors R1, R2, R3,..., Rn between a power supply voltage terminal VDD and a ground voltage terminal VSS are configured, and voltage drop by each resistor is used. A plurality of voltages are obtained, and the respective voltages are amplified by the amplifier 11 consisting of amplifiers and output as gamma voltages V1, V2, V3, ..., Vn.

Since the plurality of resistors R1, R2, R3, ..., Rn are fixed resistors whose values are fixed, the voltage output through the amplifier 11 may also be fixed.

The conventional gamma voltage generator determines the values of the resistors and configures the resistors R1, R2, R3, ..., Rn between the power supply voltage terminal VDD and the ground voltage terminal VSS. The voltage obtained by using the voltage drop caused by these signals is finally amplified by the amplifier 11 and used as gamma voltages V1, V2, V3, ..., Vn.

The gamma voltage is input to the data driving circuit 40 and divided into a plurality of gray voltages, and the divided gray voltage corresponds to predetermined digital data input to the data driving circuit 40 and finally, an analog signal. As a result, each data line is output.

As a result, the data driving circuit 40 receives one gray voltage corresponding to the value of the predetermined digital data among the gray voltages distributed by the fixed gamma voltage supplied from the gamma voltage generating circuit, and the decoder unit inside the data driving circuit. Selected through 42, it is applied to each data line connected to a predetermined pixel and applied to the liquid crystal cell.

In this case, data corresponding to red (R), green (G), and blue (B) is individually applied to each data line connected to the predetermined pixel, and the gamma voltage provided by the conventional gamma voltage generator Provides the same gamma voltage without discriminating the data corresponding to R, G, and B.

Here, since the color coordinates and color factors of R, G, and B are different from each other, the same brightness is not output when the same gray voltage is applied.

Accordingly, since the conventional gamma voltage generator applies a unitary gamma voltage to data corresponding to R, G, and B, tuning is possible only in gray where R, G, and B are combined. As a result, the color factors for the R, G, and B are determined, and since the R, G, and B cannot be accessed individually, there is a disadvantage in that color coordinate control cannot be performed.

According to the present invention, the gamma voltage is individually provided for each data corresponding to R, G, and B through the R, G, and B gamma voltage circuit configuration, and thus, fine tuning for each of the colors of R, G, and B is possible. It is an object of the present invention to provide a gamma voltage generating device and a method thereof of a liquid crystal display device which enable circuitry control of color coordinates.

In order to achieve the above object, a gamma voltage generator of a liquid crystal display according to the present invention includes a first, second and third voltage dividing circuit section for dividing an externally applied voltage into a plurality of levels, and the first, second and third voltage dividers. First, second and third amplifiers for amplifying a plurality of levels of voltages output by the circuit unit, and a data driving circuit to which a signal output from the amplifier is input, and the first, second and third voltage divider circuits Each of the resistors includes a plurality of resistors, and the external input voltages having different magnitudes are supplied to the first, second, and third voltage divider circuits by adjusting the magnitudes of the external input voltages respectively applied to the first, second, and third voltage divider circuits. The first, second, and third voltage divider circuits generate a plurality of levels of gamma voltages so as to correspond to data corresponding to red (R), green (G), and blue (B), respectively, and the first, second, and third voltage divider circuits. Gamma Voltages from Multiple Levels Is characterized in that the size can be applied differently according to the corresponding color (R, G, B).
Here, the gamma voltages output from the first, second, and third divided circuit parts are input to correspond to the first, second, and third decoder parts provided in the data driving circuit, respectively.

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In addition, in order to achieve the above object, a gamma voltage generation method of a liquid crystal display according to the present invention includes a voltage divider circuit part for dividing a voltage applied from the outside into a plurality of levels, and a voltage of a plurality of levels output by the voltage divider circuit part. In the method for generating a gamma voltage of a liquid crystal display including an amplifying unit for amplifying and outputting the amplified circuit to the data driving circuit, three divided circuit parts are provided, and each of the first divided voltages corresponds to data corresponding to red (R). A circuit portion, a second voltage dividing circuit portion corresponding to data corresponding to green (G), and a third voltage dividing circuit portion corresponding to data corresponding to blue (B), and applied to the first, second and third voltage dividing circuit portions. The external input voltages having different magnitudes are respectively supplied to the first, second, and third voltage divider circuits by adjusting the magnitudes of the external input voltages. The output gamma voltages of the plurality of levels are different in magnitude depending on the corresponding color (R, G, B), and the gamma voltages output from the respective voltage divider circuits are individually passed to the data driving circuits through the amplification unit. Characterized in that the input.
Here, the gamma voltages output from the plurality of voltage dividing circuit parts may be input corresponding to the plurality of decoder parts provided in the data driving circuit.

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According to the present invention, by providing gamma voltages individually for the data corresponding to red (R), green (G), and blue (B), fine tuning for each of the colors of R, G, and B is possible. In addition, there is an advantage in that the control of the color factors and color coordinates for R, G, and B can be circuitically enabled.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

5 is a configuration diagram briefly showing a gamma voltage generator according to the present invention.

The present invention includes a plurality of voltage dividing circuit parts of a gamma voltage generator for generating gamma voltages of multiple levels, and separately applies data corresponding to R, G, and B to apply the gamma voltages of the multiple levels. The problem of the gamma voltage generator of the present invention, that is, since the unified gamma voltage is applied to the data corresponding to R, G, B, it is possible to overcome the point that each of the fine tuning (tuning) of the R, G, B is impossible It is.

The method of the gamma voltage generator according to the present invention will be described with reference to FIG. 5.

 The gamma voltage generator according to the present invention includes first, second, and third divided circuit sections 510, 520, and 530 for dividing a voltage applied from the outside into a plurality of levels, and the first, second, and third divided circuit sections 510, First, second and third amplifiers 512, 522, and 532 for amplifying a plurality of levels of voltages output by 520 and 530, respectively, and outputting the amplified voltages to the data driving circuit are included.

In this case, the gamma voltages of the plurality of levels output from the first, second, and third divided circuit units 510, 520, and 530 are individually passed through the first, second, and third amplifiers 512, 522, and 532. It is input to the driving circuit 540.

Here, each of the divided circuit units 510, 520, and 530 may include a plurality of resistors R1, R2, R3,... Between the power supply voltage terminals VDD, VDD ′, and VDD ″ and the ground voltage terminal VSS. Rn), and a plurality of levels of gamma voltages V1, V2, V3, ..., Vn are generated using the voltage drop caused by each of these resistors. The amplifiers are amplified by the amplifiers 512, 522, and 532 that are formed of amplifiers and input to the decoders 542, 544, and 546 of the data driving circuit 540.

That is, the plurality of levels of gamma voltages output from the first, second, and third divided circuit units 510, 520, and 530 may be provided to a plurality of decoder units 542, 544, and 546 provided in the data driving circuit 540. It is input correspondingly.

Here, the first divided circuit unit 510 provides a plurality of levels of gamma voltages distributed in response to data corresponding to the red color R to reflect red characteristics (red coordinates, etc.), and the second divided circuit unit 520. Corresponds to data corresponding to green (G) to provide a plurality of levels of gamma voltages distributed by reflecting green characteristics (such as green coordinates), and the third voltage divider circuit 530 provides data corresponding to blue (G). Corresponding to the gamma voltage is provided to reflect the blue characteristics (blue coordinates, etc.).

The gamma voltage is separately provided to each of the colors R, G, and B because each of the colors R, G, and B has a color coordinate and color factor peculiar to that color. As described above, each gamma setting is performed according to each color (R, G, B), so that fine tuning and circuit color coordinate control are possible.

 As an example, data corresponding to red (R), that is, data provided to the pixel electrode of the pixel overlapping the red (R) sub-color filter is provided by the gamma voltage output from the first voltage dividing circuit unit 510. will be.

Fig. 6 is a characteristic diagram showing each of the multilevel gamma voltages generated from the gamma voltage generator according to the present invention.                     

As can be seen from FIG. 6, the gamma voltages 610, 620, and 630 of the plurality of levels output from the first, second, and third voltage divider circuits may be applied differently according to the corresponding colors R, G, and B. This can be obtained by adjusting the magnitude of the external input voltages VDD, VDD ', VDD ".

That is, according to the present invention, a gamma voltage whose size is adjusted according to each color (R, G, B) is input to the data driving circuit.

In addition, as described above, the gamma voltages corresponding to the colors output from the respective divided circuit units 510, 520, and 530 may be divided into a plurality of decoder units 542, 544, and 546 provided in the data driving circuit 540. Are input corresponding to

That is, the gamma voltage output from the first voltage dividing circuit 510 corresponds to the first decoder 542 for processing red data, and the gamma voltage output from the second voltage dividing circuit 520 processes the green data. The gamma voltage output from the third voltage divider circuit 530 corresponds to the third decoder 546 that processes blue data.

In other words, the gamma voltages of the plurality of levels are input to the data driving circuit 540 to be divided into a plurality of gray voltages, and the divided gray voltages are input to the data driving circuit 540. The analog signal is finally output to each data line as an analog signal, wherein a predetermined gray level corresponding to the value of the predetermined digital data among the gray voltages divided by the gamma voltage output from the first voltage dividing circuit unit 510. A voltage is selected through the first decoder 542 and applied to a data line connected to a predetermined pixel overlapping the red subcolor filter.                     

Similarly, among the gray voltages divided by the gamma voltages output from the second and third voltage dividing circuits 520 and 530, predetermined gray voltages corresponding to the values of the predetermined digital data are the second and third decoders 544 and 546. Are applied to a data line connected to a predetermined pixel overlapping the green (G) and blue (B) subcolor filters, respectively.

As described above, according to the present invention, since the gamma voltage is individually applied to each of data corresponding to R, G, and B, the problem associated with the conventional unified gamma voltage application, that is, the gray of the R, G, and B combined together Because only tuning is possible, R, G, and B can not be accessed individually, so it is possible to overcome the disadvantage that color coordinate control cannot be performed.

As described above, according to the gamma voltage generator and the method of the liquid crystal display according to the present invention, by providing the gamma voltage to the data corresponding to R, G, B separately, Fine tuning of colors is possible, and it has the advantage of enabling circuit control of color factors and color coordinates for R, G, and B.

Claims (10)

First, second, and third voltage dividing circuit sections for dividing an externally applied voltage into a plurality of levels; First, second and third amplifiers for amplifying a plurality of levels of voltages output by the first, second and third voltage divider circuits, respectively; A data driving circuit to which a signal output from the amplifier is input; The first, second, and third voltage divider circuits each include a plurality of resistors, and the first, second, and third voltage divider circuits respectively adjust the magnitudes of the external input voltages applied to the first, second, and third voltage divider circuits. External input voltages of different sizes are supplied, The first, second, and third voltage divider circuits generate a plurality of levels of gamma voltages so as to correspond to data corresponding to red (R), green (G), and blue (B), respectively, and the first, second, and third voltage divider circuits. The gamma voltages of the multiple levels output from are different in magnitude depending on the corresponding color (R, G, B). And a gamma voltage output from the first, second and third voltage divider circuits is input to correspond to the first, second and third decoders respectively provided in the data driving circuit. delete delete delete delete In the method for generating a gamma voltage of a liquid crystal display device comprising a voltage divider circuit for dividing a voltage applied from the outside into a plurality of levels, and an amplifier for amplifying a plurality of levels of voltage output by the voltage divider circuit and outputting the voltage to a data driving circuit. In Three divided circuit parts are provided, each of which includes a first divided circuit part corresponding to data corresponding to red (R), a second divided circuit part corresponding to data corresponding to green (G), and blue (B). It consists of a third voltage divider circuit portion corresponding to the data corresponding to The external input voltages having different magnitudes are respectively supplied to the first, second and third voltage divider circuits by adjusting the magnitudes of the external input voltages applied to the first, second and third voltage divider circuits. The gamma voltages of the plurality of levels output from the divided circuits are different in magnitude depending on the corresponding color (R, G, B), The gamma voltages output from the respective voltage divider circuits are individually input to the data driving circuits through the amplifiers, A gamma voltage generation method of a liquid crystal display device, wherein the gamma voltages output from the plurality of divided circuit parts are input to correspond to the plurality of decoder parts provided in the data driving circuit. delete delete delete delete

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