KR100559224B1 - Method of driving scanning non-sequential of lcd - Google Patents

Abstract

The present invention relates to a non-sequential scanning driving method of a liquid crystal display device in which a charging time of a gate can be sufficiently secured by applying interlaced scanning driving having a double gate pulse width using a memory block. After storing the data of the frame in the frame memory, the gate pulse scans the odd gate lines first and then the even gate line, and the gate pulse width is invalid at the first half of the gate pulse by doubling the actual gate pulse width. (Invalid) Data is input, the gate is precharged, and valid data is occupied by the other half of the gate pulse.

Description

Non-sequential scanning driving method of liquid crystal display {METHOD OF DRIVING SCANNING NON-SEQUENTIAL OF LCD}

1 is a driving block diagram of a general large screen TFT LCD.

Figure 2a is a gate pulse waveform diagram according to the present invention

2B is a waveform diagram illustrating a gate pulse and a data charging state according to the present invention.

3 is a configuration diagram showing the polarity of the liquid crystal applied voltage for each frame according to the present invention

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the driving of a liquid crystal display, and in particular, a liquid crystal display device capable of sufficiently securing the charging time of a gate by applying interlaced scanning driving having a double gate pulse width using a memory block. It relates to a non-sequential scanning driving method.

As TFT LCDs become larger and higher in resolution, reduction of gate charging time, flicker, and crosstalk are major problems.

This is because the time to charge one gate is significantly reduced as the number of gate lines to be charged for a certain frame time increases.

This causes serious problems for the flicker as the panel size increases and the overall uniformity drops.

Flicker is a kind of screen shaking, which causes the screen to shake in the eyes of the user due to the optical asymmetry caused by the distortion of the input data voltage.

In order to be able to see a shake-free screen in the liquid crystal display, at least 60 scannings should be performed per second. In driving the liquid crystal display, an AC driving method in which the data voltage Vs is inverted for each frame based on the common voltage Vcom is used to prevent deterioration of the liquid crystal.

The difference between the data voltage Vs applied to the source of the thin film transistor and the pixel voltage Vp actually applied to the liquid crystal capacitor occurs by ΔV. This is called a kick-back voltage.

This kick-back voltage is caused by the parasitic capacitance Cgd existing between the gate and drain of the thin film transistor. The kick-back voltage causes the data voltage Vs to be distorted and thus transmittance of the liquid crystal. Changes result in flicker.

And crosstalk is divided into horizontal crosstalk and vertical crosstalk.

Horizontal crosstalk is caused by capacitor coupling between the common electrode and the source electrode, and vertical crosstalk is caused by the capacitance between the source electrode and the drain electrode.

Hereinafter, a driving method of the liquid crystal display of the prior art will be described with reference to the accompanying drawings.

1 is a driving block diagram of a general large screen TFT LCD.

The driving block of the large screen TFT LCD includes a liquid crystal panel 1, a row driver 2 for applying a gate driving signal to the liquid crystal panel 1, and a column driver 3 for applying a data signal to the liquid crystal panel 1; ), A frame memory 4 for storing data input from an external system in units of frames, and a control signal (Vsync, Hsync) required for driving the liquid crystal panel 1 by the row driver 2 and the column driver 3. And a timing controller 5 for outputting a clock and the like (V, Vgl, Vcc, Vcom).

Here, the liquid crystal panel 1 defines a plurality of pixel regions by crossing a plurality of gate lines and data lines, and a data signal transmitted from the column driver 3 at an intersection portion of each of the gate lines and the data lines. A thin film transistor for switching is configured.

The thin film transistor includes a gate electrode formed on a glass substrate, a gate insulating film formed on the entire surface including the gate electrode, a semiconductor layer formed on the gate insulating film and used as a channel layer of the thin film transistor, and formed on the semiconductor layer. It consists of a source and a drain electrode.

Here, the liquid crystal capacitor having one side as the pixel electrode and the other side as the common electrode is connected to the drain electrode of the thin film transistor.

In the driving of the liquid crystal label device of the related art using such a driving block, in order to solve the problem of the filling rate and the flicker, the frame rate is added to increase the filling rate and several new driving methods are proposed to improve the flicker.

However, these improvement methods are accompanied by the addition of expensive and large-area parts to increase the product cost and place many restrictions on the circuit configuration.

Currently, when driving SXGA or UXGA using frame memory, several Mbytes of memory are required. Therefore, the internal memory cannot be used inside the controller.

In the liquid crystal display device, the auxiliary capacitor Cs is added in parallel with the liquid crystal capacitor Clc of each display pixel in order to prevent the charge held in the liquid crystal capacitor Clc from leaking through the switch element and deteriorating the display quality.

In the array substrate configuration to which the storage capacitor Cs is added, the Cs independent line configured to obtain the capacitance between the pixel electrode and the storage capacitor line by providing the storage capacitor line through the pixel electrode and the insulating film substantially parallel to the scan line. The type and the Cs on-gate type configured to obtain a capacitance between the scan line in the scanning direction front end and the pixel electrodes partially overlapped through the insulating film are known.

Here, the Cs on-gate type has an advantage that high opening ratio is achieved because unnecessary wiring such as storage capacitor lines is reduced.

However, such a liquid crystal display device of the prior art has the following problems.                         

As the screen of the liquid crystal display becomes larger, the gate charging time is gradually reduced, so that sufficient charging is not performed, thus making it difficult to transfer accurate data to the pixels.

In addition, due to an increase in the spatial uniformity of the panel, problems such as flicker and crosstalk become a critical factor that affects the screen quality of the liquid crystal display.

The present invention solves the problems of the conventional liquid crystal display device, and by using an interlaced scanning driving having a double gate pulse width using a memory block to sufficiently secure the charging time of the gate. It is an object of the present invention to provide a non-sequential scanning driving method of a liquid crystal display device.

In order to achieve the above object, a non-sequential scanning driving method of a liquid crystal display according to the present invention stores data of a corresponding frame in a frame memory, and then gate pulses scan odd gate lines first, and then even gate lines, The gate pulse width is doubled to the actual gate pulse width so that invalid data comes in and the gate is precharged in the first half of the gate pulse, and the valid data is occupied in the other half of the gate pulse. Characterized in that.

Hereinafter, a non-sequential scanning driving method of a liquid crystal display according to the present invention will be described in detail with reference to the accompanying drawings.

2A is a gate pulse waveform diagram according to the present invention, and FIG. 2B is a waveform diagram showing a gate pulse and a data charging state according to the present invention.

3 is a configuration diagram showing the polarity of the liquid crystal applied voltage for each frame according to the present invention.

The present invention is to provide a large-screen, high-quality liquid crystal display using an interlaced scanning driving method with a double gate pulse width using a memory block.

The configuration displays the panel by using a memory to scan odd gate lines and then even gate lines.

At this time, as shown in Figure 2a, the gate pulse is twice the actual pulse width. In this way, the charging time of the gate can be sufficiently secured, and the problem of gate charging in the large-screen liquid crystal display can be solved.

In addition, as shown in FIG. 2B, since interlaced scanning performs scanning with one skip column, crosstalk by neighboring columns is significantly reduced.

In addition, as shown in FIG. 3, dot inversion is possible while using a double gate, and by dividing one frame into odd and even charges, the average value of the difference in transmittance due to the difference in voltage applied to the liquid crystal is reduced by half. Flicker visibility is reduced by half.

Such a non-sequential scanning driving method of the liquid crystal display of the present invention will be described in more detail as follows.

According to the present invention, as shown in FIGS. 2A and 2B, first, one frame of data is stored in a frame memory, and then a gate pulse scans odd gate lines first and then even gate lines.

The gate scanning sequence of FIG. 2A is scanned in the order of gate 1 → gate 3 → gate 5 → gate 7 → gate 2 → gate 4 → gate 6 → gate 8.

Data corresponding to each gate line may be read from the stored frame memory in the gate scanning order described above.

The gate pulse width is twice the actual gate pulse width to precharge the gates.

In the front half of the gate pulse, invalid data is input, the gate is precharged, and the valid data is occupied by the other half of the gate pulse.

Such a method can solve the gate charging problem in the large-screen liquid crystal display.

In the double gate driving method, since the pixels connected to the Nth gate line and the N + 1th gate line have the same polarity, only the column inversion method is possible.

However, in the case of using the driving method of the present invention, since the scanning is performed with one skip column, the polarity of the data of the last line of the odd gate and the first line data of the even gate must be different for the dot inversion method. There should be no overlap when scanning two gates.

The non-sequential scanning driving method of the liquid crystal display of the present invention has the following effects.

First, in addition to the driving of the dot inversion method, the column inversion, frame inversion, and line inversion can act on the driving method of all.

Second, by using the memory to reduce the frequency of the data in half through the interlace of the data can reduce the EMI problem caused by the data.

Third, since the non-sequential scanning is scanned into one skip column, there is an effect of significantly reducing crosstalk by neighboring columns.

Fourth, by occupying one frame by odd or even, the average value of the difference in transmittance due to the difference in voltage applied to the liquid crystal is reduced by half, thereby reducing the flicker visibility by half.

Claims (3)

In driving the liquid crystal display device, After storing the data of the frame in the frame memory, the gate pulse scans the odd gate lines first and then the even gate lines. The gate pulse width is doubled to the actual gate pulse width so that invalid data enters in the first half of the gate pulse and the gate is precharged. A method for driving a non-sequential scanning of a liquid crystal display according to claim 1, wherein valid data is occupied in the remaining 1/2 gate pulse. 2. The method of claim 1, wherein non-sequential scanning is scanned in one skip column to suppress crosstalk by neighboring columns. 2. The liquid crystal of claim 1, wherein in the dot inversion method, two gates are scanned so that overlap does not occur in order to change polarities of the odd-gate last line data and the even-gate first line data. Non-sequential scanning driving method of a display device.

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