KR20030048846A - device for driving liquid crystal device - Google Patents

Abstract

PURPOSE: A liquid crystal display driver is provided to control the color without losing video data and prevent picture quality deterioration due to the adjustment of the color. CONSTITUTION: A driver of a liquid crystal display having a liquid crystal panel(1) on which a plurality of gate lines and data lines are formed, and a plurality of pixels each of which has a switching element connected to each gate line and each data line includes a scan driver(2), a data driver(3), and a gradation voltage generator(6). The scan driver provides gate voltage to the gate lines. The data driver supplies gradation voltage to the data lines according to a data signal applied to the data lines. The gradation voltage generator generates gradation voltage for each of R, G and B data items to provide the gradation data to the data driver.

Description

Device for driving liquid crystal device

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display (hereinafter, referred to as an LCD), and more particularly, to a driving device of a liquid crystal display for controlling a gray voltage supplied to a liquid crystal display.

Recently, display devices are also required to be lighter and thinner in accordance with the light weight and thickness of personal computers and televisions, and according to such demands, flat displays such as liquid crystal displays (LCDs) instead of cathode ray tubes (CRTs) are required. Panel-type displays are being developed.

In the display device, a function of adjusting the color of the displayed image is generally provided, and in a PC, the user can adjust the gamma curve by the red, red, green, and blue colors. It has a built-in function. For example, if the basic gamma of each of R, G, and B is '2.2', and if you want to emphasize the red color a little more, that is, to 'redish', the user sets the gamma of R to be less than or equal to 2.2 Make the colors appear a bit brighter.

However, a problem arises in that gray scales are not expressed as a whole after adjusting color for a specific color. This is because part of the image signal is distorted in a situation where the display signal such as a PC processes the video signal. For example, if it is intended to be 'redish', data loss occurs during the offset process because the original R image signal data is distorted by being offset toward the bright side.

As such, grayscales are not accurately represented due to the occurrence of data loss, and thus deterioration of image quality occurs.

Therefore, the technical problem to be achieved by the present invention is to solve the above problems, and to provide a color adjustment without losing image data in the liquid crystal display device.

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

2 is a diagram illustrating in detail a gray voltage generator according to a first exemplary embodiment of the present invention.

3 is a diagram illustrating in detail a gray voltage generator according to a second exemplary embodiment of the present invention.

4 is an output waveform diagram of a gray voltage generator according to a second exemplary embodiment of the present invention.

5 is a diagram illustrating in detail a gray voltage generator according to a third exemplary embodiment of the present invention.

6 is an output waveform diagram of a gray voltage generator according to a third exemplary embodiment of the present invention.

7 is a diagram illustrating in detail a gray voltage generator according to a fourth exemplary embodiment of the present invention.

According to an aspect of the present invention, there is provided a driving apparatus of a liquid crystal display device, wherein a plurality of gate lines and data lines are formed in row and column directions, respectively, and are defined as intersections of the gate lines and data lines. A drive device for a liquid crystal display device comprising a liquid crystal panel having a plurality of pixels having switching elements connected to the gate line and the data line, respectively, the device comprising: a scan driver configured to supply a gate voltage to the gate line; A data driver supplying a corresponding gray voltage to the data line according to an applied data signal; And a gray voltage generator for generating gray voltages for each of R (red), G (green), and B (blue) data, and supplying the gray voltages to the data sections.

The gray voltage generator may include an R gray voltage generator configured to generate a plurality of positive gray voltages and negative gray voltages for the R data; A G gray voltage generator configured to generate a plurality of positive gray voltages and negative gray voltages for the G data; And a B gray voltage generator for generating a plurality of positive gray voltages and negative gray voltages for the B data, wherein each of the gray voltage generators is between a first voltage and a reference voltage applied from the outside and a reference voltage and a second voltage. A first series of resistors for generating a plurality of positive gray voltages, including a plurality of resistors disposed in series between the first resistor string; And a second resistor string that generates a plurality of negative gray voltages, including a plurality of resistors disposed in series between the second voltage and the reference voltage and between the reference voltage and the third voltage.

Here, each of the gray voltage generators compares and amplifies the adjusted voltage and the first set voltage which are varied according to a user's operation to provide the center voltage of the second resistor string to generate the negative polarity generated by the second resistor string. A first operational amplifier configured to vary a gray voltage of the first op amp; And a second operational amplifier configured to comparatively amplify the voltage output from the first amplifier and the second set voltage to provide the center voltage of the first resistor string so that the negative gray voltage generated by the second resistor string is varied. It may further include.

On the other hand, each gray voltage generator receives externally the positive voltage and the negative voltage corresponding to the white level, the positive voltage corresponding to the black level and the negative voltage from the outside, and thus the positive white gray voltage and the positive voltage The black gray voltage, the negative white gray voltage, and the negative black gray voltage can be output.

In addition, the gray voltage generator is embedded in the data driver, and receives a plurality of positive voltages and negative voltages corresponding to the white level, positive voltages corresponding to the black level, and negative voltages from the outside. It may also generate a gray scale voltage of.

Hereinafter, with reference to the drawings will be described in detail an embodiment of the present invention.

1 illustrates a structure of a liquid crystal display device showing an embodiment of the present invention.

As shown in FIG. 1, a liquid crystal display according to an exemplary embodiment of the present invention includes an LCD panel 1, a gate driver 2, a data driver 3, a driving voltage generator 4, and a timing controller ( 5) and a gradation voltage generator 6.

Herein, a normal white mode liquid crystal display is described as an example, but the present invention is not limited thereto and may be equally applied to a normally black mode liquid crystal display.

The data driver 3 is also called a source driver and serves to lower the voltage value transmitted to each pixel in the LCD panel 1 by one line. More specifically, the data driver 3 stores the digital data from the timing controller 5, which will be described later, in a shift register in the data driver, and then a signal (LOAD signal) for instructing the LCD panel 1 to lower the data. In this case, the voltage corresponding to each data is selected and the voltage is transferred to the LCD panel 1.

The gate driver 2 is also called a scan driver, and serves to open a way for data from the data driver 3 to be transferred to the pixel. Each pixel of the LCD panel 1 is turned on or off by a TFT serving as a switch, which is turned on and off by applying a constant voltage (Von, Voff) to a gate.

In this way, the Von voltage for turning on the gate and the Voff voltage for turning off the gate signal are generated by the driving voltage generator 4. The driving voltage generator 4 generates not only the above-mentioned Von and Voff voltages but also a Vcom voltage which is a reference for the data voltage difference in the TFT.

The timing controller 5 generates a digital signal for driving the data driver 3 and the gate driver 2. Specifically, the timing controller 5 generates a signal that enters the drivers 2 and 3, adjusts timing of data, and adjusts clock. It plays a role.

The gray voltage generator 6 generates a gray voltage entering the data driver 3, and in particular, generates a gray voltage for each of R, G, and B data, and supplies the gray voltage to the data driver 3. That is, in the embodiment of the present invention, the color tone of each of R, G, and B is adjusted by adjusting the gradation voltage of the liquid crystal without manipulating the image data.

2 illustrates the structure of the gray voltage generator according to the first embodiment of the present invention.

As shown in FIG. 2, the gray voltage generator 6 according to the first embodiment of the present invention includes a plurality of R gray voltage generators 61 and G for generating a plurality of gray voltages for R. As shown in FIG. A gray scale voltage generator 62 for generating a gray scale voltage of the gray scale voltage generator 63 generates a plurality of gray voltages for B.

Each of the gradation voltage generators 61 to 63 is provided with a plurality of first resistor strings for generating a positive gradation voltage formed between the first external voltage AVDD and the second external voltage 0. RR1 to RR5, RG1 to RG5, RB1 to RB5, and a plurality of second resistor strings RR6 to RR10, RG6 to RG10, and RB6 to connected in series with the first resistor string and generating negative gray voltages. RB10), and the first and second resistor rows are spaced apart by the spacer resistors RRM, RGM, and RBM.

Therefore, in the R gray voltage generator 61, a plurality of R gray voltages having a positive polarity are formed by a plurality of resistors RR1 to RR5 connected in series between the first voltage AVDD applied from the outside and the separation resistor RRM. VREF1R + to VREF5R + are generated. Further, a plurality of negative gradation voltages VREF6R- to VREF10R- are generated by the plurality of resistors RR6 to RR10 connected in series between the separation resistor RRM and the second voltage.

In addition, in the G gray voltage generator 62, a plurality of G gray voltages having a positive polarity are formed by a plurality of resistors RG1 to RG5 connected in series between the first voltage AVDD applied from the outside and the separation resistor RGM. VREF1G + to VREF5G + are generated. Further, a plurality of negative gradation voltages VREF6G-VREF10G- are generated by the plurality of resistors RG6 to RG10 connected in series between the separation resistor RGM and the second voltage.

In addition, in the B gray voltage generator 63, a plurality of B gray voltages having a positive polarity are formed by a plurality of resistors RB1 to RB5 connected in series between the first voltage AVDD applied from the outside and the separation resistor RBM. VREF1B + to VREF5B + are generated. Further, a plurality of negative gradation voltages VREF6B- to VREF10B- are generated by the plurality of resistors RB6 to RB10 connected in series between the separation resistor RBM and the second voltage.

The positive or negative gray voltage of each of the R, G, and B generated in this manner may be input to the data driver, respectively, and color may be adjusted for each of the R, G, and B colors.

However, in the first embodiment, since the user cannot directly adjust the colors by R, G, and B, in the second embodiment, the user adjusts the colors by causing the gray voltages generated by R, G, and B to be different from each other. To help.

3 illustrates a structure of a gray voltage generator according to a second embodiment of the present invention.

The R, G, and B gray voltage generators according to the second exemplary embodiment of the present invention are configured in the same manner. Therefore, the structure and operation will be described by taking only the R gray voltage generator as an example for convenience of description.

As shown in FIG. 3, the gray voltage generator according to the second exemplary embodiment of the present invention has a separation resistor between the first external voltage AVDD and the second external voltage 0 as in the first embodiment. The first resistor strings RR1 to RR5 and the second resistor strings RR6 to RR10 are separated by RRM. Unlike the first embodiment, the first resistor string and the first resistor string are formed according to a signal input from the outside. The apparatus further includes a voltage adjusting unit 616 for varying the center potential of the two resistance strings so that the gray voltage is varied.

In the first resistor strings RR1 to RR5 according to the first embodiment, the voltage applied from the voltage adjusting unit 616 is applied to the contact between the resistor RR3 and the resistor RR4, so that the VREF3R + gray scale voltage which is the center voltage of positive polarity. Becomes In the second resistor strings RR6 to RR10, the voltage applied from the voltage adjusting unit 616 is applied to the contact between the resistor RR7 and the resistor RR8 to become the negative center voltage VREF8R−gradation voltage. .

The voltage adjusting unit 616 that provides the center voltage of each resistor string includes a first amplifier OP1 having a non-inverting input terminal connected to a control voltage Vin, and an inverting input terminal of an output terminal of the first amplifier OP1. It includes a second amplifier (OP2) connected to. The inverting terminal (-) of the first amplifier OP1 receives a voltage output from the output terminal of the first amplifier OP1 and then divided by the division resistors RA and RB. As the inverting terminal, the voltage output through the output terminal and the voltage of the output terminal of the first amplifier OP1 are divided and input by the division resistors RC and RD. The first external voltage AVDD is divided and input to the non-inverting terminal of the second amplifier OP1 by the division resistors RE and RF.

Here, the output voltage of the first amplifier OP1 is applied as the center voltage of the negative gray voltage of the second resistor strings RR6 to RR10, and the output voltage of the second amplifier OP2 is the first resistor string RR1 to It is applied as the center voltage of the positive gradation voltage of RR5).

In the second embodiment of the present invention having such a structure, the positive voltage and the negative voltage are generated symmetrically with respect to the potential of the first external voltage AVDD / 2. The first amplifier OP1 performs positive amplification in the negative voltage range with respect to the voltage, and the second amplifier OP2 negatively amplifies the difference between the amplified voltage and the AVDD / 2 voltage to positive voltage. To form a range.

Specifically, the control voltage Vin applied according to a color selected by the user from outside is changed, and the first amplifier OP1 of the voltage controller 611 amplifies the control voltage input to the non-inverting terminal to input the voltage. A voltage having a phase equal to the amplitude of is outputted and applied as the negative center voltage VREF8R- of the second resistor strings RR6 to RR10.

The voltage output from the first amplifier OP1 is also adjusted by the resistors RA and RB to be input to the inverting terminal of the second amplifier OP2, and the second amplifier OP2 is input to the inverting terminal. The output voltage of OP1 is used as an input, and an antiphase voltage symmetrical with the first external voltage is output and applied to the positive center voltage VREF3R + of the first resistor strings RR1 to RR5.

Accordingly, the output voltages of the amplifiers OP1 and OP2 vary according to the input adjustment voltage Vin, so that the center voltage VREF3R + of the positive gray voltage and the center voltage VREF8R- of the negative gray voltage are substantially variable. As a result, the values of the positive grayscale voltages VREF1R + to VREF5R + and the negative grayscale voltages VREF6R- to VREF10R- are different.

On the other hand, the G gray voltage generator and the B gray voltage generator also operate in the same manner as the R gray voltage generator described above, so that the user can adjust the color tone by changing the gray voltage for each R, G, and B as needed from the outside. have.

4 shows a gray voltage output waveform according to the second embodiment of the present invention. Referring to FIG. 4, it can be seen that the user can input the adjustment voltage to symmetrically adjust the gray voltages of the positive and negative polarities by using two amplifiers.

However, in the second embodiment, it can be seen that the potential VREF5 + corresponding to the white level and the potential VREF10− corresponding to the black level are not constant.

Therefore, in the third embodiment, when the gray voltage is adjusted for each of R, G, and B by the user, the potential of the white level and the black level is constant so that the liquid crystal characteristics are maintained.

5 illustrates a structure of a gray voltage generator according to a third exemplary embodiment of the present invention. The R, G, and B gray voltage generators according to the third exemplary embodiment are configured in the same manner, and thus, for the convenience of description, the structure and operation will be described by taking only the R gray voltage generator as an example.

As shown in FIG. 5, the gray voltage generator according to the third embodiment of the present invention has the same structure as that of the second embodiment, and VREF5R + corresponding to the white level is the first reference voltage (V). ), And VREF6R- is connected to the second reference voltage (V). VREF1R + corresponding to the black level is connected to the third reference voltage V, and VREF10R- is connected to the fourth reference voltage V.

Since the potentials of the white level and the black level are fixed in this manner, even when the center voltage is changed by the voltage adjusting unit 616, VREF5R + and VREF6R- corresponding to the white level and VREF1R + and VREF10R- corresponding to the black level are Each maintains a certain level.

Meanwhile, in the case of the G gray voltage generator, VREF5G corresponding to the white level is connected to the first common voltage V1 and VREF6G- is connected to the second common voltage V5. VREF1G + corresponding to the black level is connected to the third common voltage V6, and VREF10G- is connected to the fourth common voltage V10. Also, in the case of the B gray voltage generator, VREF5B corresponding to the white level is connected to the first common voltage V1, and VREF6B- is connected to the second common voltage V5. VREF1B + corresponding to the black level is connected to the third common voltage V6, and VREF10B- is connected to the fourth common voltage V10. Therefore, even when the reference voltage is changed by the user's operation, VREF5G +, VREF6G-, VREF5B +, and VREF6GB- corresponding to the white level and VREF1G +, VREF10G-, VREF5B + and VREF6B- corresponding to the black level are maintained at the constant level, respectively. Done.

Meanwhile, in the third embodiment, each common voltage V1, V5, V6, V10 is shown as a power source, but an input using an amplifier or the like is also possible.

6 illustrates a gray voltage output waveform according to the third embodiment of the present invention. Referring to FIG. 6, while the user inputs an adjustment voltage and symmetrically adjusts the gray scale voltages of the positive and negative polarities, the potential VREF5 + corresponding to the white level and the potential VREF10− corresponding to the black level are constant. It can be seen.

In the first to third embodiments described above, the positive gray level voltage and the negative gray level voltage are generated for each of R, G, and B, thereby increasing the number of input terminals input to the data driver.

For example, in the past, a total of 10 input terminals were required as five terminals for the positive gray voltage and five terminals for the negative gray voltage, but according to the embodiment described above, about 30 input terminals were required. .

Therefore, in the fourth embodiment of the present invention, the number of input terminals input to the data driver is maintained as about 10 as in the prior art, so as not to affect the driver input terminal design.

7 illustrates the structure of the gray voltage generator according to the fourth embodiment of the present invention.

In the fourth embodiment of the present invention, the division resistors (RR2 to RR5, RG2 to RG5, RB2 to RB5) and R, G, and B for generating the positive gray scale voltages of R, G, and B according to the embodiments described above. The division resistors RR6 to RR9, RG6 to RG9, and RB6 to RB9 for generating the negative gray scale voltage of the data driver are incorporated. In addition, externally adjusting voltages for adjusting the reference voltages V1, V5, V6, and V10 corresponding to the white and black levels according to the third embodiment, and the positive and negative gray level voltages of R, G, and B, respectively. Apply three each.

Accordingly, the signals input to the data driver are four reference voltages and six voltages respectively adjusted for R, G, and B, so that ten signals are input to the data driver. Therefore, the gradation voltages of R, G, and B can be individually adjusted without changing the design of the terminal input to the data driver.

In the fourth embodiment having such a structure, the adjustment voltages VIN8R, VIN8G, and VIN8B for adjusting the negative gradation voltage become the outputs of the first amplifier as in the second embodiment, and the adjustment for adjusting the positive gradation voltage The voltages VIN3R, VIN3G, and VIN3B become the outputs of the second amplifier.

Therefore, the gray scale voltages of the positive and negative polarities of R, G, and B generated by the first and second resistor strings built in the data driver 3 are varied according to the adjustment voltage input from the outside. At this time, since the generation of the grayscale voltages of the positive and negative polarities by the first and second resistance strings built in the data driver is performed in the same manner as in the above-described embodiment, detailed description thereof will be omitted.

Meanwhile, in order to further reduce the number of signal terminals input to the data driver, the first and second amplifiers generating the adjustment voltage may be incorporated in the data driver. In this case, three input terminals of the data driver may be reduced. have.

According to a number of embodiments described above, color can be easily adjusted by adjusting the gradation voltages of R, G, and B, respectively, without losing image data.

As mentioned above, although embodiment of this invention was described, this invention is not limited only to the above-mentioned embodiment, A various other deformation | transformation and a change are possible.

According to the present invention described above, the color of the liquid crystal display can be easily adjusted. In particular, since color can be adjusted without losing image data, deterioration of image quality due to color adjustment can be prevented.

In addition, the user can easily adjust the gradation voltage of each of R, G, and B according to taste.

In addition, the gray scale voltages of R, G, and B can be changed without changing the existing input terminal design.

Claims (5)

A plurality of gate lines and data lines are formed in the row and column directions, respectively, and a plurality of pixels having switching elements connected to the gate line and the data line are formed in an area defined by the intersection of the gate line and the data line, respectively. In the drive device of the liquid crystal display device containing the liquid crystal panel, A scan driver supplying a gate voltage to the gate line; A data driver supplying a corresponding gray voltage to the data line according to an applied data signal; A gray voltage generator for generating gray voltages for each of R (red), G (green), and B (blue) data, and supplying the gray voltages to the data driver. Driving device for a liquid crystal display comprising a. The method of claim 1, The gray voltage generator, An R gray voltage generator configured to generate a plurality of positive gray voltages and negative gray voltages for the R data; A G gray voltage generator configured to generate a plurality of positive gray voltages and negative gray voltages for the G data; And B gray voltage generator which generates a plurality of positive gray voltages and negative gray voltages for the B data. Including; Each of the gray voltage generators includes a plurality of resistors disposed in series between a first voltage and a reference voltage applied from the outside and between a reference voltage and a second voltage to generate a plurality of positive gray voltages. ; And a second resistor string generating a plurality of negative gray voltages, including a plurality of resistors disposed in series between the second voltage and the reference voltage and between the reference voltage and the third voltage. Driving device for a liquid crystal display comprising a. The method of claim 2, Each gray voltage generator, A first voltage for comparing and amplifying a control voltage and a first set voltage applied according to a user's operation as a center voltage of the second resistor string so as to vary the negative gray voltage generated by the second resistor string. Operational amplifiers; And A second operational amplifier configured to comparatively amplify the voltage output from the first amplifier and a second set voltage to provide the center voltage of the first resistor string so that the negative gray voltage generated by the second resistor string is varied; The driving device of the liquid crystal display device further comprising. The method of claim 2, The gray voltage generator The external positive and negative voltages corresponding to the white level, the positive voltage corresponding to the white level, and the negative voltage from the outside are input from the outside, and the positive white gray voltage, the positive black gray voltage, and the negative polarity Driving device of liquid crystal display for outputting with white gray voltage and negative black gray voltage In claim 1, The gray voltage generator is built in the data driver, and receives a plurality of gray levels from the outside by receiving a positive voltage and a negative voltage corresponding to the white level, a positive voltage corresponding to the black level, and a negative voltage from the outside. A drive device for a liquid crystal display device that generates a voltage.