KR20080022689A - Driving apparatus, liquid crystal display including the same and driving method thereof - Google Patents

Abstract

Provided are a driving device capable of adjusting a response speed of a liquid crystal display according to a usage environment, a liquid crystal display including the same, and a driving method thereof. The driving apparatus includes a storage unit having a plurality of lookup tables (LUTs) in which respective correction data according to different response speeds are stored in a matrix form, and the plurality of lookups which receive a control signal and are stored in the storage unit. A timing controller for selecting one of the tables, correcting an image signal using the correction data of the selected lookup table, and generating an image data signal as the corrected image signal, and receiving the corresponding image data signal and corresponding gamma And a data driver for selecting a voltage and providing the selected gamma voltage as a data driving signal to the liquid crystal panel.

Description

A driving apparatus, a liquid crystal display including the same, and a driving method thereof TECHNICAL FIELD

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

FIG. 2 is an equivalent circuit diagram of one pixel of the liquid crystal display of FIG. 1.

3 is a block diagram of the timing controller of FIG. 1.

4 is a waveform diagram illustrating a corrected image signal compared to an input image signal according to the driving device of FIG. 1.

(Explanation of symbols for the main parts of the drawing)

100: liquid crystal panel 200: gate driver

300: data driver 350: gamma voltage generator

400: timing controller 410: frame memory

420: correction unit 500: storage unit

600: OSD control unit

The present invention relates to a driving device, a liquid crystal display including the same, and a driving method thereof, and more particularly, to a driving device capable of adjusting a response speed of a liquid crystal display according to a usage environment, a liquid crystal display including the same, and a driving thereof. It is about a method.

In general, a liquid crystal display device obtains a desired image signal by applying an electric field to a liquid crystal material having an anisotropic dielectric constant injected between two substrates, and controlling the amount of light transmitted through the substrate by adjusting the intensity of the applied electric field. to be.

In such a liquid crystal display device, a liquid crystal material has a slow operation speed due to a liquid crystal material and a cell gap, that is, a gap between two substrates. Therefore, the screen is blurred in high speed driving, for example, when displaying a moving image. This happens.

Recently, in order to improve the operation speed of such liquid crystals, ADCC or Dynamic Capacitance Compensation (DCC) driving technology has been used. Here, ADCC or DCC driving is a method of artificially improving the operation speed of the liquid crystal display by modulating the image signal according to whether or not the input image signal is changed by using a preset look-up table.

However, the conventional ADCC and DCC driving technology does not adequately cope with various response speeds for the end user's environment by using a lookup table optimized for one response speed. An operation for improvement causes defects in the liquid crystal display, for example, screen distortion.

An object of the present invention is to provide a driving device capable of adjusting the response speed of a liquid crystal display device according to a usage environment.

Another object of the present invention is to provide a liquid crystal display device including such a driving device.

Another object of the present invention is to provide a method of driving such a liquid crystal display.

The technical problems of the present invention are not limited to the above-mentioned technical problems, and other technical problems not mentioned will be clearly understood by those skilled in the art from the following description.

According to another aspect of the present invention, there is provided a driving apparatus including a storage unit including a plurality of lookup tables (LUTs) in which respective correction data according to different response speeds are stored in a matrix form, and a control signal. A timing controller for selecting one of a plurality of lookup tables stored in the storage unit, correcting an image signal using correction data of the selected lookup table, and generating an image data signal as a corrected image signal, and an image data signal. And a data driver for selecting a corresponding gamma voltage and providing the selected gamma voltage as a data driving signal to the liquid crystal panel.

The liquid crystal display according to the exemplary embodiment of the present invention for achieving the another technical problem includes such a driving device.

According to another aspect of the present invention, there is provided a method of driving a liquid crystal display device, including: a liquid crystal panel displaying an image and a plurality of correction data stored in a matrix form according to different response speeds; A liquid crystal display including a storage having a lookup table (LUT), a timing controller for correcting an input N-frame video signal to generate an image data signal, and a data driver for providing the image data signal to the liquid crystal panel. Preparing a selected lookup table among a plurality of lookup tables by a response speed selection signal provided from the outside, and providing the corresponding lookup table to the timing controller; and an N-frame video signal provided from the outside and a pre-stored N-1 frame. Compare video signals, and adjust the correction data of the selected lookup table according to the comparison result. Correcting the N-frame video signal by using the same; and generating an image data signal using the corrected N-frame video signal.

Specific details of other embodiments are included in the detailed description and the drawings.

Advantages and features of the present invention and methods for achieving them will be apparent with reference to the embodiments described below in detail with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but can be implemented in various different forms, and only the embodiments make the disclosure of the present invention complete, and the general knowledge in the art to which the present invention belongs. It is provided to fully inform the person having the scope of the invention, which is defined only by the scope of the claims. Like reference numerals refer to like elements throughout.

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

1 is a block diagram of a liquid crystal display according to an exemplary embodiment of the present invention, and FIG. 2 is an equivalent circuit diagram of one pixel of the liquid crystal display of FIG. 1.

First, referring to FIG. 1, the liquid crystal display 700 may largely include a liquid crystal panel 100 and driving devices 200, 300, 350, 400, 500, and 600. The driving devices 200, 300, 350, 400, 500, and 600 may be, for example, the timing controller 400, the gate driver 200, the data driver 300, the gamma voltage generator 350, and the storage 500. ) And the OSD control unit 600.

In the equivalent circuit, the liquid crystal panel 100 includes a plurality of display signal lines G ₁ to G _N and D ₁ to D _M , and a plurality of unit pixels connected thereto and arranged in a matrix form. pixel).

The display signal lines G ₁ to G _N and D ₁ to D _M are provided with a plurality of gate lines G ₁ through G _N transmitting gate driving signals to the liquid crystal panel 100 and a plurality of data lines transferring data driving signals. (D ₁ ~ D _M ). Here, the gate lines G ₁ to G _N extend in the row direction of the liquid crystal panel 100 so that they are substantially parallel to each other, and the data lines D ₁ to D _M extend in the column direction of the liquid crystal panel 100 to form a gate. Intersect the lines G ₁ to G _N , and are substantially parallel to each other.

Each unit pixel may include a switching element Q connected to the display signal lines G ₁ to G _N , D ₁ to D _M , a liquid crystal capacitor Clc, and a storage capacitor Cst connected thereto. The sustain capacitor Cst may be omitted as necessary.

Referring to FIG. 2, the liquid crystal panel 100 includes two display panels 110 and 120 facing each other, for example, a first display panel 110 and a second display panel 120, and between the two display panels 110 and 120. It includes a liquid crystal layer 130 interposed. In addition, as described above, the first display panel 110 includes the gate lines G _N-1 and G _N , the data lines D _M-1 crossing the gate lines G _N-1 , and G _N , and a switching element. Q and the pixel electrode PE, and the second display panel 120 includes a common electrode CE, a color filter CF, etc. corresponding to the pixel electrode PE of the first display panel 110. It may include.

In this case, the switching element Q uses the pixel electrode PE of the first display panel 110 and the common electrode CE of the second display panel 120 as two terminals, and the liquid crystal interposed between the two electrodes PE and CE. Layer 130 functions as a dielectric. In addition, the pixel electrode PE is connected to the switching element Q, and the common electrode CE is formed on the entire surface of the second display panel 120 and receives the common voltage Vcom. In this case, the common electrode CE may be provided in the first display panel 110. In this case, both electrodes PE and CE may be formed in a linear or bar shape.

The storage capacitor Cst may be formed by overlapping a separate signal line (not shown) and the pixel electrode PE provided on the first display panel 110. In this case, a predetermined voltage such as a common voltage Vcom is disposed on the separate signal line. Can be applied (independent wiring method). In addition, the storage capacitor Cst may be formed such that the pixel electrode PE overlaps the front-end gate line directly above the insulator (shear gate method).

Meanwhile, in order to implement color display, each unit pixel should display a color, which is possible by providing a red, green, or blue color filter CF in a region corresponding to the pixel electrode PE. The color filter CF may be formed in a corresponding region of the second display panel 120 and may be formed above or below the pixel electrode PE of the first display panel 110.

In addition, a polarizer (not shown) for polarizing light may be attached to an outer surface of at least one of the first display panel 110 and the second display panel 120 of the liquid crystal panel 100.

In order to provide driving and control signals to the liquid crystal panel 100, the liquid crystal display 700 may include a timing controller 400, a gate driver 200, a data driver 300, a gamma voltage generator 350, and a storage device. The unit 500 and the OSD controller 600 may be included.

The timing controller 400 may include a gate driver from a plurality of signals provided from an external graphic controller (not shown), for example, image signals R, G, and B, and a plurality of control signals Vsync, Hsync, MCLK, and DE. The controller 200 generates a control signal for controlling operations of the 200 and the data driver 300, and provides the corresponding control signal to the gate driver 200 and the data driver 300.

In addition, the timing controller 400 generates image data signals R ′, G ′, and B ′ by appropriately processing the image signals R, G, and B provided from the outside in accordance with operating conditions of the liquid crystal panel 100. do. The image data signals R ′, G ′, and B ′ generated in this way are provided to the data driver 300. Specifically, the timing controller 400 is stored in the storage unit 500 to be described later according to a predetermined control signal provided from an external, for example, external OSD control unit 600, for example, a response speed selection signal R_C. One lookup table of the plurality of lookup tables LUT is selected, and the inputted image signals R, G, and B are appropriately corrected using the correction data LUTD of the selected lookup table. The corrected image signals R, G, and B may be provided to the data driver 300 as image data signals R ', G', and B '. The timing controller 400 will be described in detail later with reference to FIG. 3.

The storage unit 500 may store a plurality of lookup tables. In detail, the storage unit 500 may include a plurality of lookup tables in which correction data LUTDs according to different response speeds are stored in a matrix form, and the lookup table is predetermined from the timing controller 400. When a signal of, for example, the lookup table selection signal S_C is provided, the correction data LUTD of the corresponding lookup table is provided to the timing controller 400.

The storage unit 500 may be configured of, for example, an EEPROM (Electricaiiy Erasable Programmable Read-Only Memmory), but is not limited thereto. In addition, in the present exemplary embodiment, the storage unit 500 has been described as an example of being implemented as an independent unit. However, the present invention is not limited thereto, and the storage unit 500 may be integrated with the timing controller 400.

The driving voltage generator (not shown) generates a plurality of driving voltages and provides them to the gate driver 200 and the liquid crystal panel 100. The driving voltage generated by the driving voltage generator may include, for example, a gate on voltage Von, a gate off voltage Voff, a common voltage Vcom, and the like.

The gate driver 200 is connected to the gate lines G1 to Gn formed in the liquid crystal panel 100, and the gate driver 200 includes a gate driving voltage Von and a gate off voltage Voff provided from the driving voltage generator. The signal is provided to the gate lines G1 to Gn.

The data driver 300 is connected to the data lines D1 to Dm formed in the liquid crystal panel 100, and the image data signals R ′, G ′, and B ′ and the gamma voltage generator provided from the timing controller 400 are provided. A plurality of gray voltages are generated based on the plurality of gamma voltages provided from 350, and the generated gray voltages are selected and applied to the unit pixels as data driving signals, and are typically formed of a plurality of integrated circuits.

The gate driver 200 and the data driver 300 may be mounted on the liquid crystal panel 100 in the form of a plurality of driving integrated circuit chips, or may be mounted on a flexible printed circuit film (FPC). The tape may be attached to the liquid crystal panel 100 in the form of a tape carrier package (TCP). In addition, the gate driver 200 or the data driver 300 may be integrally formed on the liquid crystal panel 100 together with the display signal lines G1 to Gn and D1 to Dm and the switching element Q.

The gamma voltage generator 350 may generate two sets of gamma voltages related to transmittance of a unit pixel. That is, one of the two sets is the positive voltage, and the other is the negative voltage. Herein, the positive voltage and the negative voltage mean voltages having opposite polarities with respect to the common voltage Vcom, and are alternately provided to the liquid crystal panel 100 during inversion driving.

The OSD controller 600 provides a control signal, for example, a response speed selection signal R_C, to the timing controller 400. The OSD controller 600 may be located outside the liquid crystal display 700, for example, on a set, and may be electrically connected to the timing controller 400 through a predetermined cable. .

The driving apparatus of the liquid crystal display according to the exemplary embodiment of the present invention has been described above. The driving apparatus of the present exemplary embodiment provides a plurality of lookup tables for response speeds of different liquid crystal display devices, thereby allowing a user to easily adjust the response speed of the liquid crystal display device according to a user's environment. The driving failure of the liquid crystal display due to the operation can be reduced.

3 is a block diagram of the timing controller of FIG. 1. Hereinafter, the timing controller described above will be described in detail with reference to FIGS. 1 and 3.

1 and 3, the timing controller 400 may largely include a frame memory 410 and a correction unit 420.

The frame memory 410 stores the N frame image signals R, G, and B provided from an external graphic maker (not shown), and stores previously stored frames, that is, the N-1 frame image signals R-1 and G. -1, B-1) is output.

The correction unit 420 may correct the N frame image signals R, G, and B provided from the outside to generate corrected N frame image signals R ', G', and B '. In detail, the correction unit 420 may be configured to output the N-frame video signals R, G, and B provided from the outside, and the N- 1 frame video signals R-1, G-1 and B-1 output from the frame memory 410. And the N frame image signals R, G, and B may be corrected using the correction data LURD of the lookup table provided from the storage unit 500 according to the comparison result. In this case, the corrected N-frame video signals R ', G', and B 'are over-shoot waveforms higher than a target voltage of the N-frame video signals R, G, and B when the N frame is driven by the liquid crystal display. Allow this to be authorized. The N frame image signals R ', G', and B 'corrected in this way are output to the data driver 300 as image data signals.

As described above, the timing controller 400 including the frame memory 410 and the correction unit 420 may control a control signal, for example, a response speed selection signal R_C from an external device, for example, the OSD controller 600. In this case, the timing controller 400 may receive correction data LUTD of the corresponding lookup table from the storage 500 according to the response speed selection signal R_C. Here, the timing controller 400 provides a predetermined signal, for example, a lookup table selection signal S_C, to the storage unit 500, and the storage unit 500 stores a plurality of previously stored by the lookup table selection signal S_C. One lookup table of the lookup tables LUT ₁ to LUT _N may be selected, and correction data LUTD of the selected lookup table may be provided to the timing controller 400.

Hereinafter, an operation of the liquid crystal display including the timing controller described above will be described.

4 is a waveform diagram illustrating a corrected image signal compared to an input image signal according to the driving device of FIG. 1. Hereinafter, operations of the above-described driving apparatus and the liquid crystal display including the same will be described in detail with reference to FIGS. 1, 3, and 4.

First, the timing controller 400 may control an R, G, and B image signals R, G, and B from the external graphic controller (not shown), an input control signal such as a vertical synchronization signal Vsync, The horizontal synchronization signal Hsync, the main clock MCLK, and the data enable signal DE are provided.

Also, the timing controller 400 generates a gate control signal CONT1 and a data control signal CONT2 based on the input control signal. In this case, the gate control signal CONT1 generated by the timing controller 400 is provided to the gate driver 200, and the data control signal CONT2 and the image data signals R ′, G ′, and B ′ are the data driver 300. ) May be provided.

The gate control signal CONT1 may include a vertical synchronization signal STV indicating the start of output of the gate on pulse (gate on voltage section), a gate clock signal CPV for controlling the output timing of the gate on pulse, and a gate on pulse. And an output enable signal OE defining a width. In addition, the data control signal CONT2 applies a horizontal synchronization start signal STH indicating the start of input of the image data signals R ', G', and B ', and a data driving signal corresponding to the data lines D1 to Dm. May include a load signal LOAD, an inversion driving signal RVS for inverting the polarity of the data driving signal with respect to the common voltage Vcom, a data clock signal HCLK, and the like.

In addition, the timing controller 400 generates an image data signal by appropriately processing the image signals R, G, and B input from outside to meet the operating conditions of the liquid crystal panel 100. In detail, the timing controller 400 compares the N frame video signals R, G, and B input from the outside with the prestored N-1 frame video signals R-1, G-1, and B-1. According to the result, the N frame image signals R, G, and B may be corrected using the correction data LUTD of the lookup table. The N frame image signals R ', G', and B 'corrected as described above may be provided to the data driver 300 as image data signals.

Referring to [Table 1] in more detail as follows.

TABLE 1

Table 1 shows an example of a lookup table. Here, the row direction of Table 1 represents the correction data (LUTD) of the previous frame, that is, the N-1 frame video signals R-1, G-1, and B-1, and the column direction represents the current frame, that is, the N frame. The correction data LUTD of the video signals R, G, and B is shown.

Referring to FIG. 3 and Table 1, the timing controller 400 may correct the N-frame image signals R, G, and B input from the outside using the correction data LUTD of the lookup table. . In detail, the correction unit 420 of the timing controller 400 includes N frame image signals R, G and B input from the outside and N-1 frame image signals R-1 and G provided from the frame memory 410. -1, B-1) is compared with each other. At this time, the correction unit 420 is the current frame, that is, the N-frame video signal (R, G, B) according to the comparison result of the above two image signals (R, G, B, R-1, G-1, B-1) ) May be corrected using the correction data LUTD.

For example, the N frame video signals R, G, and B input from the outside to the correction unit 420 are 32 gray digital signals (00100000), and are input from the frame memory 410 to the correction unit 420. Assuming that the N-1 frame video signals R-1, G-1, and B-1 are zero gray digital signals (00000000), the correction unit 420 of the timing controller 400 is shown in [Table 1]. The N frame image signals R, G, and B may be corrected using the lookup table correction data LUTD. That is, the correction unit 420 adjusts the correction data of the lookup table according to the comparison value of the N frame video signals R, G, and B and the N-1 frame video signals R-1, G-1, and B-1. LUTD), for example, 48 may be selected, and the N-frame video signals R, G, and B may be corrected by 48 gray digital signals 00110000 using the selected correction data LUTD.

As described above, the above-described correction data LUTD is one of a plurality of lookup tables for different response speeds selected by the lookup table selection signal S_C provided from the timing controller 400 to the storage 500. It may be correction data (LUTD) of a lookup table of. Therefore, the driving apparatus of the present exemplary embodiment may correct the N-frame image signals R, G, and B by applying different lookup table correction data LUTD for various response speeds, thereby correcting driving failure of the liquid crystal display. It can be improved.

In addition, at least one over shoot waveform may be applied to the corrected N frame image signals R ′, G ′, and B ′ during an N frame operation of the liquid crystal display.

Specifically, referring to FIG. 4, the raw video signal, that is, the N-frame video signals R, G, and B input from the outside is displayed as 0 gray in the N-1 frame operation of the liquid crystal display, and other frames For example, 32 grays may be displayed in N, N + 1, and N + 2 frames. The corrected N-frame video signals R ', G', and B 'are displayed as 0 gray in the N-1 frame operation of the liquid crystal display, and form a predetermined overshoot A in the N frame operation to 48 gray. Can be displayed. The corrected N frame image signals R ', G', and B 'may be displayed as 32 grays in N + 1 and N + 2 frames.

That is, the timing controller 400 controls the N frame video signals R, G, and B input from the outside in the N frame operation of the liquid crystal display, and the N frame video signals R 'and G' including the overshoot A. , B ') can be output by correcting and outputting a high-speed response of the liquid crystal display.

Here, although the timing controller of the present embodiment has been described with an example of comparing and correcting image signals for two frames, the present invention is not limited thereto, and the timing controller includes three frames, for example, N-1, N, and N. Image signals for +1 frames may be compared and corrected.

The data driver 300 sequentially receives the image data signals R ′, G ′, and B ′ corresponding to the unit pixels in one row according to the data control signal CONT2 provided from the timing controller 400, and thus gamma voltages. By selecting a gamma voltage corresponding to each of the image data signals R ', G', and B ', the image data signals R', G ', and B' are converted into corresponding data driving signals.

The gate driver 200 applies the gate-on voltage Von to the gate lines G ₁ to G _N in response to the gate control signal CONT1 provided from the timing controller 400, and thus the gate lines G ₁ to G _N. Turn on the switching element (Q) connected to.

Here, while a gate-on voltage Von is applied to one gate line G ₁ to G _N and a row of switching elements Q connected thereto is turned on (this period is referred to as' 1H 'or' 1 horizontal period ( horizontal period) 'and is equal to one period of the horizontal synchronization signal STH, the data enable signal DE, and the gate clock signal CPV], and the data driver 300 associates each data driving signal with a corresponding data line. Supply to (D1 ~ Dm). The data driving signal thus supplied is applied to the corresponding unit pixel through the turned-on switching element Q.

In this manner, the gate-on voltages Von are sequentially applied to all the gate lines G ₁ to G _N during one frame to apply data driving signals to all unit pixels. When one frame ends, the next frame starts, and the inversion driving signal RVS applied to the data driving unit 300 is applied so that the polarity of the data driving signal applied to each unit pixel is opposite to that of the data driving signal in the previous frame. The state is controlled ('frame inversion'). In this case, the polarity of the data driving signal flowing through one data line D ₁ to D _M is changed ('line inversion') or applied to one pixel row according to the characteristics of the inversion driving signal RVS within one frame. The polarity of the data drive signal may also be different ('dot inversion').

Although embodiments of the present invention have been described above with reference to the accompanying drawings, those skilled in the art to which the present invention pertains may implement the present invention in other specific forms without changing the technical spirit or essential features thereof. I can understand that. Therefore, it should be understood that the embodiments described above are exemplary in all respects and not restrictive.

As described above, according to the driving apparatus and the liquid crystal display including the same according to the present invention, by providing a look-up table for various response speeds, the response speed of the desired liquid crystal display can be easily selected according to the use environment. Driving failure of the liquid crystal display according to the speed change can be improved.

Claims (7)

A storage unit having a plurality of lookup tables (LUTs) in which correction data according to different response speeds are stored in a matrix form; A timing of receiving a control signal, selecting one of a plurality of lookup tables stored in the storage unit, correcting an image signal using the correction data of the selected lookup table, and generating an image data signal as the corrected image signal. Control unit; And And a data driver configured to receive the image data signal, select a corresponding gamma voltage, and provide the selected gamma voltage as a data driving signal to a liquid crystal panel. According to claim 1, The control signal is a response speed selection signal provided from an external on screen display (OSD) controller. And the timing controller is provided with the correction data corresponding to the response speed selected by the response speed selection signal. According to claim 1, And the storage unit is an EEPROM. The method of claim 1, wherein the timing controller, A frame memory configured to store an N frame video signal input from the outside and output an N-1 frame video signal; And And a correction unit configured to compare the N-1 frame image signal with the N frame image signal and correct the N frame image signal using the correction data of the lookup table selected according to a comparison result. The method of claim 4, wherein And the correcting unit corrects at least one overshoot waveform to the N-frame video signal based on the correction data. A liquid crystal panel displaying an image; And A driving device for generating an image data signal as an image signal input from the outside and providing the same to the liquid crystal panel, the liquid crystal display comprising the driving device according to any one of claims 1 to 4. A storage unit including a liquid crystal panel displaying an image, a plurality of lookup tables (LUTs) in which respective correction data according to different response speeds are stored in a matrix form, and correcting an input N frame image signal to obtain an image data signal. Preparing a liquid crystal display including a timing controller to generate and a data driver to provide the image data signal to the liquid crystal panel; Selecting one of the lookup tables from among the plurality of lookup tables according to a response speed selection signal provided from an external device and providing the selected lookup table to the timing controller; Comparing the N frame image signal provided from the outside with a previously stored N-1 frame image signal, and correcting the N frame image signal using the correction data of the lookup table selected according to a comparison result; And And generating the image data signal using the corrected N frame image signal.

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