KR100646785B1 - Liquid crystal display device using an impulse type and method thereof - Google Patents

Abstract

The present invention is a liquid crystal display device using an impulse method and a driving method thereof.

According to the present invention, the gate driver sequentially supplies a scan signal to the gate line of the liquid crystal display panel, and the data voltage corrector corrects the data voltage provided from the outside so as to have an impulse light emission method suitable for moving image, thereby correcting the data correction voltage. The data driver outputs the data correction voltage to the data line of the liquid crystal display panel.

As a result, it is possible to implement a moving picture, particularly a fast moving picture, by adapting the holding light emitting display method to an impulse light emitting display method in order to realize a moving picture naturally.

Video, correction, data voltage, frame, impulse method, holding method, light emission, gate pulse

Description

Liquid crystal display device using an impulse method and a driving method thereof

1 illustrates an equivalent circuit of each pixel in a general LCD.

2 is a waveform diagram illustrating a change in transmittance according to an impulse emission method of a CRT.

3 is a waveform diagram illustrating a change in transmittance of a pixel when the response speed of the liquid crystal is slower than the frame period.

4 is a waveform diagram illustrating a change in transmittance of a pixel when the response speed of the liquid crystal is faster than the frame period.

5 is a view showing a liquid crystal display using an impulse light emission method according to an embodiment of the present invention.

6 is a waveform diagram illustrating an impulse light emission method according to a first embodiment of the present invention.

7 is a waveform diagram illustrating an impulse light emission method according to a second embodiment of the present invention.

8 is a waveform diagram illustrating an impulse light emission method according to a third embodiment of the present invention.                 

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

100: liquid crystal display panel 200: gate driver

300: data driver 400: data voltage correction unit

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device and a driving method thereof, and more particularly, to a liquid crystal display device and a driving method thereof using an impulse type light emission method to which a data voltage corrected to be suitable for moving image is applied.

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 display devices are being developed.

In general, an LCD applies an electric field to a liquid crystal material having an anisotropic dielectric constant injected between two substrates, and adjusts the intensity of the electric field to control the amount of light transmitted through the substrate to obtain a desired image signal. Device. Such LCDs are typical among portable flat panel displays, and among them, TFT LCDs using thin film transistors (TFTs) as switching elements are mainly used.

In the TFT-LCD, each pixel may be modeled as a capacitor having a liquid crystal as a dielectric, that is, a liquid crystal capacitor. The equivalent circuit of each pixel in the LCD is shown in FIG. 1.

As shown in FIG. 1, each pixel of the liquid crystal display includes a TFT 10 having a source electrode and a gate electrode connected to a data line Dm and a gate line Sn, respectively, and a drain electrode of the TFT 10. And a liquid crystal capacitor Cl connected between the common voltage Vcom and a storage capacitor Cst connected to the drain electrode of the TFT 10.

Referring to FIG. 1, when the gate on signal is applied to the gate line Sn and the TFT 10 is turned on, the data voltage Vd supplied to the data line Sn is transferred through the TFT 10 to each pixel electrode ( (Not shown). Then, an electric field corresponding to the difference between the pixel voltage Vp and the common voltage Vcom applied to the pixel electrode is applied to the liquid crystal (equivalently represented by the liquid crystal capacitor in FIG. 1), and thus transmittance corresponding to the intensity of the electric field. To allow light to pass through. In this case, the pixel voltage Vp should be maintained for one frame. In FIG. 1, the storage capacitor Cst is used to maintain the pixel voltage Vp applied to the pixel electrode.

Recently, as TFT LCDs are widely used as display devices of televisions as well as display devices of computers, there is an increasing need to implement moving images.

When a continuous picture is displayed at a high speed of more than 24 sheets / sec, a human is perceived as a moving image because the recognition of the moving image has an afterimage effect of storing 0.04 seconds of an image recognized by the human eye.

FIG. 2 is a waveform diagram illustrating a change in transmittance according to an impulse emission method of a CRT. FIG. 3 is a waveform diagram illustrating a change in transmittance of a pixel when the response speed of a liquid crystal is slower than a frame period. It is a waveform diagram for demonstrating the change of the transmittance | permeability of a pixel when the response speed of a liquid crystal is faster than a frame period.

As shown in FIG. 2, since a light emitting display such as a CRT is an impulse light emitting method, a blanking section exists even after a large luminance difference between front and rear frames when a moving image is implemented, resulting in an afterimage of a human eye. Is rewarded with effect. Therefore, a natural moving picture can be realized.

However, in LCDs, the response speed of liquid crystals is slower than the frame period, and as shown in FIG. 3, the LCD does not accurately display an image signal to be displayed, and thus a tail is drawn when a moving image is implemented. Therefore, in order to implement moving images in LCD, first, the response speed of the liquid crystal needs to be much faster than the frame period. However, even if the response speed of the liquid crystal is fast, a natural moving image is still impossible if the holding type emission method is used as it is.

In addition, as shown in FIG. 4, since the LCD continuously displays the image display within the frame time until the next image signal, the change of the applied voltage due to the change of the capacitance of the liquid crystal during the holding time causes a change in the transmittance. There is a problem in that it is difficult to implement a natural moving image while overlapping with the afterimage effect of the eyes.

Accordingly, the present invention has been made in an effort to solve such a conventional problem, and an object of the present invention is to provide a liquid crystal display using an impulse method suitable for realizing moving images.                         

Another object of the present invention is to provide a method of driving a liquid crystal display device using the impulse type light emission method.

In order to achieve the above object, a liquid crystal display using an impulse light emission method according to one feature of the present invention,

At least one gate line transferring a scan signal, and at least one data line transferring a data voltage and insulated from and intersecting the gate line, the gate line and the data line being respectively surrounded by the gate line and the data line. A liquid crystal display panel including one or more pixels arranged in a matrix form having a switching element connected to the liquid crystal display;

A gate driver sequentially supplying the scan signal to the gate line;

A data voltage corrector for outputting a data correction voltage by correcting a data voltage provided from an external graphic controller to have an impulse light emitting method suitable for moving image; And

And a data driver for supplying the data correction voltage to the data line.

In addition, another object of the present invention is a driving method of a liquid crystal display using the impulse-type light emission method

A matrix having at least one gate line, at least one data line insulated from and intersecting the gate line, and a switching element formed in an area surrounded by the gate line and the data line and connected to the gate line and the data line, respectively In the driving method of a liquid crystal display device comprising a plurality of pixels arranged in the form,

(a) generating a data correction voltage by correcting the data voltage so as to have an impulse emission type suitable for moving image;

(b) sequentially supplying scan signals to the gate lines; And

(c) supplying the data correction voltage generated in step (a) to the data line.

According to the liquid crystal display and the driving method using the impulse-type light emission method, in order to realize a moving picture naturally, by switching the driving light-emitting display method to the impulse-type light emission display method, it is more adapted to the realization of moving images, particularly fast moving image. Can be implemented as

Then, embodiments will be described so that those skilled in the art can easily implement the present invention.

5 is a view showing a liquid crystal display using an impulse light emission method according to an embodiment of the present invention.

As shown in FIG. 5, the liquid crystal display according to the exemplary embodiment of the present invention includes a liquid crystal display panel 100, a gate driver 200, a data driver 300, and a data voltage corrector 400.                     

The liquid crystal display panel 100 has a plurality of gate lines S1, S2, S3,..., Sn for transmitting a gate-on signal, and data lines D1, D2,. .., Dm) is formed. Each region surrounded by the gate line and the data line constitutes a pixel, and each pixel is connected to the thin film transistor 110 and the drain electrode of the thin film transistor 110 having a gate electrode and a source electrode connected to the gate line and the data line, respectively. The pixel capacitor Cl and the storage capacitor Cst are included.

The gate driver 200 outputs a scan signal for turning on the TFT of the pixel so that the data voltage can be applied to the pixel. More specifically, the gate driver 200 sequentially applies the gate-on voltage to the gate line, thereby applying the gate-on voltage. The TFT 110 to which the gate electrode is connected to the gate line is turned on.

The data driver 300 applies an actual liquid crystal driving voltage to the liquid crystal by using the input image data. More specifically, the data driver 300 applies the data correction voltage Vd 'received from the data voltage corrector 400 to the corresponding gray level. The voltage is applied to each of the data lines D1, D2, ..., Dm by changing the voltage (data voltage).

The data voltage corrector 400 receives the data voltage Vd from an external graphic controller (not shown) and provides the impulse data correction voltage Vd 'to the data driver 300 to be suitable for video implementation. . In this case, the data voltage corrector 400 may exist as a stand-alone unit or may be integrated into the graphic controller (not shown) or the data driver 300.                     

An example of an impulse type data correction voltage Vd 'suitable for moving image output from the data voltage corrector 400 is a positive voltage for displaying a general image in the first half of the first frame, and black in the second half of the first frame. A reset voltage for image realization, a negative voltage for general image display in the first half of the second frame, and a reset voltage for black image realization in the second half of the second frame. Here, the first frame is an odd or even frame, and the second frame is an even or odd frame.

In addition, another example of the impulse data correction voltage Vd 'suitable for moving image is a positive data voltage for displaying a normal image in a first frame, and a reset voltage for implementing a black image in a second frame. Here too, the first frame is an odd or even frame and the second frame is an even or odd frame.

Another example of the data correction voltage Vd 'is a positive data voltage for displaying a normal image in a first frame, a negative data voltage for displaying a normal image in a second frame, and a black image in a third frame. Reset voltage for implementation. Here, the first frame is the second frame, the second frame is the third frame, and the third frame is repeated after the first frame.

A video implementation method using a liquid crystal display device suitable for video implementation described in FIG. 5 will be described.

First, when the second gate line is being scanned, a predetermined pulse is applied from the gate driver 200 to the gate electrode, and signal voltages are applied to all of the source electrode lines S1, S2,..., Sn. If a signal voltage capable of driving a liquid crystal is applied to a specific source electrode line and a voltage smaller than the liquid crystal driving voltage is applied to the remaining source electrode lines, only the pixel line included in the specific source electrode line will be operated. Only the pixel to which the pulse is applied to the middle gate electrode is turned on, and if the pulse is not applied to the remaining gate electrodes, only the TFT corresponding to the specific pixel is turned on, and all the remaining TFTs are turned off to maintain the signal voltage applied to the liquid crystal capacitor. .

By this operating principle, it is possible to drive all the pixels of the panel by applying pulses to all the gate electrodes sequentially and applying the signal voltage to the corresponding source electrodes. In this way, after displaying one frame of image, successively displaying another frame enables moving picture display.

Hereinafter, an operation of a liquid crystal display device suitable for implementing a video according to various embodiments of the present disclosure will be described.

6 is a waveform diagram illustrating an impulse light emission method according to a first embodiment of the present invention.

As shown in Fig. 6, the first half of one frame, preferably the 1 / 2th frame, performs image display as in the prior art, and a black voltage is displayed by applying a reset voltage to the second half, preferably the 2 / 2th frame. To minimize the transmittance to set the blanking time.

More specifically, the image is displayed by applying a positive data voltage during the first half frame of the odd (or even) frame, and the reset voltage is applied during the remaining half of the odd (or even) frame. To implement the black state. In addition, the image is displayed by applying a negative data voltage during the first half of the even (or odd) frame, and the black state by applying a reset voltage during the remaining half of the even (or odd) frame. Implement

According to the first embodiment of the present invention, the polarity of the voltage applied to the liquid crystal must be maintained in one frame in order to suppress the generation of the DC component. Of course, it is necessary to find the optimal condition between the blanking time and the frame period, but the setting of the blanking time allows the conventional holding light emitting method used in the CRT to be switched to the impulse light emitting method, so that a natural moving picture like CRT can be realized.

7 is a waveform diagram illustrating an impulse light emission method according to a second embodiment of the present invention.

As shown in Fig. 7, the gate frequency is conventional, one frame outputs a positive data correction voltage to display pixels, and the next frame implements a black state by applying a reset voltage as the data correction voltage. .

In this impulse type light emission method, since the typical frame frequency is 60 Hz, the image is switched to 30 sheets / sec and can be recognized as a moving image by the human eye.

8 is a waveform diagram illustrating an impulse light emission method according to a third embodiment of the present invention.

As shown in FIG. 8, the data correction voltage is a positive data voltage for the first frame implementation, the data correction voltage is a negative data voltage for the second frame implementation, and the data correction voltage is the Reset voltage. At this time, in order to implement the third embodiment of the present invention, the response time of the liquid crystal should be faster than one frame time.

In the first embodiment of the present invention, the gate frequency has to be increased twice as much as in the conventional art, and the gate pulse width must be reduced by half, so that the charging of the pixel electrode is insufficient when the resolution is increased, so that the environment cannot be adapted to the resolution. can do.

In addition, in the second embodiment of the present invention, about half of the entire image display frame is outputted with a reset voltage for black implementation, so that the overall luminance is halved, and since all reset voltages are of the same polarity, preferably zero volts, The environment in which the component occurs may be encountered.

However, according to the third embodiment of the present invention, since the reset voltage for implementing the black state is also polarized symmetrically, it is possible to prevent the generation of the DC component and also apply the reset voltage only for one third of the entire image display frame. The luminance loss is also less than 1/2 mentioned in FIG. 7, and the gate pulse width is the same as in the conventional driving method.

In addition, the third embodiment of the present invention may have a lower quality of moving image than the second embodiment mentioned in FIG. 6, but may greatly improve the quality of moving image implementation compared to the conventional holding method.

Although the above has been described with reference to a preferred embodiment of the present invention, those skilled in the art will be able to variously modify and change the present invention without departing from the spirit and scope of the invention as set forth in the claims below. I can understand that you can.

As described above, according to the present invention, the switching type of the holding type light emitting display method is driven to the impulse type light emitting display method in order to realize the moving image naturally, and thus, the moving type can be more adaptively implemented.

Claims (9)

At least one gate line transferring a scan signal, and at least one data line transferring a data voltage and insulated from and intersecting the gate line, the gate line and the data line being respectively surrounded by the gate line and the data line. A liquid crystal display panel including one or more pixels arranged in a matrix form having a switching element connected to the liquid crystal display; A gate driver sequentially supplying the scan signal to the gate line; A data voltage corrector for converting a data voltage provided from an external graphic controller into an impulse data correction voltage; And A data driver for supplying the data correction voltage to the data line Liquid crystal display using an impulse type light emission method comprising a. The method of claim 1, wherein the data correction voltage, The first half of the first frame is a positive voltage for displaying a normal image, the second half of the first frame is a reset voltage for implementing a black image, The first half of the second frame is a negative voltage for displaying a normal image, the second half of the second frame is a reset voltage for implementing a black image, the liquid crystal display using an impulse type light emission method. The method of claim 1, The data correction voltage alternates a frame with a positive data voltage for displaying a normal image and a reset voltage for implementing a black image, and has the reset voltage after the positive data voltage. Liquid crystal display. The method of claim 1, wherein the data correction voltage, The first frame is a data voltage of positive polarity for normal image display, The second frame contains negative data voltages for general image display, The liquid crystal display using the impulse light emission method, characterized in that the third frame is a reset voltage for implementing a black image. The liquid crystal display device of claim 4, wherein the response time of the liquid crystal is equal to or greater than one frame time. A matrix form having at least one gate line, at least one data line insulated from and intersecting the gate line, and a switching element formed in a region surrounded by the gate line and the data line and connected to the gate line and the data line, respectively In a driving method of a liquid crystal display device comprising a plurality of pixels arranged in (a) converting the data voltage into an impulse data correction voltage; (b) sequentially supplying scan signals to the gate lines; And (c) supplying the data correction voltage generated in step (a) to the data line; Method of driving a liquid crystal display using an impulse-type light emitting method comprising a. The method of claim 6, wherein the data correction voltage, The first half of the first frame is a positive voltage for displaying a normal image, the second half of the first frame is a reset voltage for implementing a black image, The first half of the second frame is a negative voltage for displaying a normal image, and the second half of the second frame is a reset voltage for implementing a black image. The data correction voltage of claim 6, wherein the data correction voltage alternately has a positive data voltage for displaying a normal image and a reset voltage for implementing a black image, and has the reset voltage after the positive data voltage. A method of driving a liquid crystal display using an impulse light emission method. The method of claim 6, wherein the data correction voltage, The first frame is a data voltage of positive polarity for normal image display, The second frame contains negative data voltages for general image display, The driving method of the liquid crystal display using the impulse light emission method, characterized in that the third frame is a reset voltage for implementing a black image.

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