JP2003255905A - Liquid crystal display - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid crystal display in which the flicker phenomenon of a specific still picture pattern is hard to be seen. <P>SOLUTION: A liquid crystal display has a function for setting arbitrarily polarities of the gate signal which is scanned at the nth time and a source signal which is outputted in accordance with the gate signal when gate wirings 101 are successively scanned from the first wiring to the final wiring. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an active matrix type liquid crystal display device, especially a high quality TFT (Thin) used for a display such as a computer or a television.
The present invention relates to an active matrix type liquid crystal display device.

[0002]

2. Description of the Related Art In a conventional liquid crystal module, particularly a TFT liquid crystal display device, the electric potential of a pixel electrode arranged on the array substrate side is alternately applied to the electric potential of a counter electrode arranged on the color filter substrate side. As a result, the liquid crystal is AC driven. In the case of a normal TFT liquid crystal display device, the panel is driven line-sequentially, and the gates of all pixels are turned on only once per frame, and the pixel electrodes are charged with a potential.

When a positive potential is applied to all pixels for one frame and a negative potential is applied in the next frame, flicker is easily visible, so that the positive and negative potentials are switched for each line, the 1H inversion driving method, A column inversion driving method in which the potential is switched for each column of the source wiring, a dot inversion method in which the potentials of all adjacent dots are switched, and the like are adopted.

[0004]

The liquid crystal module has one
As described above, the potential of each pixel is inverted every time a screen (one frame) is drawn, and so-called AC driving is performed. However, this driving method has a problem that the flicker phenomenon is easily visible due to a specific display pattern. The flicker phenomenon in a liquid crystal device appears as flickering when the effective voltage applied to the liquid crystal is different between when a positive potential is applied (normal rotation) and when a negative voltage is applied (inversion) when the liquid crystal is driven by alternating current. Say a phenomenon. The flicker phenomenon does not occur unless the effective voltage applied to the liquid crystal is exactly the same during forward rotation and reverse rotation, and there is no imbalance in the amount of light that passes through the liquid crystal, but device variation factors (temperature and voltage fluctuations) , The characteristics of the hardened film, the in-plane variation due to the entry of impurities, and the variation in the time factor), it is difficult to completely adjust. In the conventional liquid crystal device, a 1H inversion driving method in which data is inverted every horizontal scanning is generally used. In this method, the potential of each pixel is inverted every vertical scanning, but the potential of the adjacent gate lines is inverted every 1H, so that the human eye has a difference in luminance between the gate lines. It looks offset. With this method, the flicker phenomenon does not appear in a general image, but 1
When a striped pattern for every H or an image repeated for every 1H is displayed, the effect of inverting the potential every horizontal scan disappears, and the frequency component of vertical scan (about 30 Hz)
But it becomes visible as flicker.

Therefore, recently, a dot inversion method for performing normal rotation and inversion for each dot has been adopted. In this method, the flicker phenomenon is inconspicuous unless a dot checkered pattern (an image in which black and white is inverted for each dot) is displayed. This is also the same as the 1H inversion drive, in which adjacent dots are inverted so that the brightness difference is offset. However, if the same pattern as the inverted pattern is displayed as a still image, it is inverted. Effect disappears and the flicker phenomenon becomes noticeable. However, since the dot checkered pattern is a display in which adjacent red, green, and blue dots are reversed in black and white, the flicker phenomenon is not noticeable unless a very special pattern (FIG. 2B) is displayed. On the other hand, in the case of 1H inversion driving, a black-and-white repetitive pattern for each horizontal line becomes a pattern in which flicker is conspicuous (hereinafter referred to as a flicker pattern), and thus is a pattern that is relatively easily encountered (FIG. 2A).

In any case, if the inversion pattern is changed and a still image that cancels the pattern is displayed,
The effect of offsetting flicker disappears, and it may appear as flicker.

Further, the potential applied to the source electrode is low,
Since capacitive coupling drive with a high optical response speed is based on the 1H inversion drive system, it is a drive system that has the disadvantages of flicker on the one hand, while having the excellent characteristics as described above.

[0008]

Therefore, according to the present invention, a plurality of source wirings are formed at respective intersections of a plurality of source wirings and gate wirings, which are formed in a matrix on one of opposing substrates with a liquid crystal interposed therebetween. A pixel electrode connected to a switching element electrically connected to each intersection of the gate line and the gate line is formed, and a storage capacitor is formed between the pixel electrode and the gate line adjacent to the pixel electrode. A liquid crystal display device that sequentially scans up to the last one, wherein the polarities of a gate signal to be scanned nth and a source signal output corresponding to the gate signal are arbitrarily set. It is a display device.

Further, the present invention has m tables or m algorithms for determining the polarities of the gate signal scanned in the nth position and the source signal output corresponding to the gate signal, The liquid crystal display device is characterized in that a table or an algorithm to be used is sequentially switched from 1 to m every time the gate wiring is scanned.

According to the present invention, when the liquid crystal is driven by alternating current,
It is possible to provide a liquid crystal module characterized in that flicker is hard to see even if the balance of the effective voltage applied to the liquid crystal at the time of forward rotation and the time of reverse rotation is slightly disturbed.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an explanatory diagram relating to driving of a liquid crystal display device in an embodiment of the present invention. In the present embodiment, JP-A-2-913 and JP-A-2-913 are used.
As disclosed in Japanese Laid-Open Patent Publication No. 157815, a driving method for modulating the potential of a pixel electrode by changing the potential of a gate wiring adjacent to the pixel electrode and capacitively coupled (capacitive coupling drive)
The present invention was applied to.

Reference numeral 101 is a gate wiring, 102 is a source wiring, and the gate wirings are G0, G1, G2, G3, ...
The source wirings are numbered S1, S2, S3 ...
For example, since the thin film transistor (TFT) 104 is turned on in the waveform 103, the source signal (105) of S1 at that time is taken in and the TFT (104) is turned off. Immediately after this, the waveform 106 is applied to the gate wiring in the previous stage, and the potential taken in via the capacitor is shifted in the positive direction. Therefore, the potential raised to the potential of the waveform 105 is applied to the pixel. It will be. Similarly, in the next frame, the source waveform 107 is applied, and the potential difference of the waveform 108 shifts the potential captured by the TFT (104) in the more negative direction.

FIG. 2 shows the direction in which the potential is applied for each frame in the model of FIG. 1 when the potential is in the normal direction is represented by "+" and when it is inverted is represented by "-". Represents the first frame, and represents the second frame.

In the present embodiment, →→→→→
→ ... is repeated, but another pattern may be incorporated to make a complicated repetition. However, the electric potential of each pixel must be such that DC is not accumulated on average. In the present embodiment, since and are only inverting all the pixel potentials, the numbers of “+” and “−” are equal, and the average potential is applied when “+”. And the potential applied when the potential is "-".

Although the above description does not refer to the image to be displayed, it is assumed that the image is uniform on the entire screen (for example, a white image). Here, the potential applied to the source is black level 0 V and white level 5 V during forward rotation, and conversely, black level 5 V and white level 0 V during inversion. Figure 2
When an image in which black and white is inverted every 1H as shown in (a) is displayed, the voltage as shown in FIG. It will appear as a flicker. This embodiment
If 1 is applied, the electric potential as shown in FIG. 4 is repeatedly displayed, so that the flicker is canceled by the frame and the flicker becomes difficult to see. "+"
By making the "-" pattern a more complicated combination, it becomes possible to make flicker less visible.

[0016]

As described above, according to the present invention, it is possible to make flicker that occurs in a specific pattern depending on a driving method inconspicuous.

[Brief description of drawings]

FIG. 1 is an explanatory diagram regarding driving of a liquid crystal display device.

FIG. 2 is a diagram showing a flicker pattern.

FIG. 3 is a diagram showing applied potentials for each frame in a conventional driving method.

FIG. 4 is a diagram showing an applied potential for each frame in the embodiment of the present invention.

FIG. 5 is a diagram showing a direction in which a potential is applied for each frame in the embodiment of the present invention.

[Explanation of symbols]

101 gate wiring 102 source wiring 103 ON potential of gate 104 TFT 105 Source potential during forward rotation 106 Potential shift of gate 107 Source potential at inversion

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) G09G 3/20 623 G09G 3/20 623U

Claims (2)

[Claims] 1. At each intersection of a plurality of source wirings and a gate wiring formed in a matrix on one of substrates facing each other with a liquid crystal interposed therebetween, each intersection of the plurality of source wirings and a gate wiring is electrically connected to each intersection. Pixel electrodes connected to the switching elements that are electrically connected to each other are formed, a storage capacitor is formed between the pixel electrode and a gate wiring adjacent to the pixel electrode, and the first to the last of the gate wirings are sequentially scanned. A liquid crystal display device, wherein the polarities of a gate signal scanned in the nth position and a source signal output corresponding to the gate signal are arbitrarily set. 2. A gate signal to be scanned n times,
It has m tables or m algorithms for determining the polarities of the source signal output corresponding to the gate signal, and the tables or algorithms to be used in order from 1 to m for each scanning of the gate wiring. The liquid crystal display device according to claim 1, wherein the liquid crystal display device is switched.