JPS6177886A - Liquid crystal matrix panel - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a liquid crystal display panel, and particularly to the structure of an active matrix, box-shaped liquid crystal display panel in which a switching element is arranged in each pixel.

(Prior art) Among the various flat panel displays, active matrix and strip type liquid crystal displays are being actively developed because they are capable of large capacity display, color display, large area display, and low power consumption. The general structure of an active matrix liquid crystal display panel consists of an active matrix substrate provided with switching elements, a counter electrode substrate, a liquid crystal layer filled between these two substrates, a polarizing plate, etc. be done. FIG. 4 shows a portion of a plan view of an example of an active matrix substrate. Display electrodes 41 are arranged in a matrix on an insulating substrate, and a large number of scanning lines (dirt lines) 44 and a large number of signal lines (drain lines) 43 are arranged orthogonally insulated from each other.

A liquid crystal is connected to one display electrode 41 corresponding to one pixel 45.
N, switching elements 42 for turning off are similarly arranged in a matrix, and the scanning line 44 and the signal line 4
3 and a display electrode 41 are connected to each other. Scan, @4
4 and the signal on the signal line 43, the switching element 42
is turned on, a signal is transmitted to the display electrode 41, the liquid crystal between the opposing substrate electrodes (not shown in FIG. 4) is switched, and the desired display is obtained. Note that one pixel here refers to a pixel for displaying one color in the case of multicolor display.

(Problems to be Solved by the Invention) The structure of the conventional active matrix substrate as described above has the following drawbacks. That is,
According to the conventional structure, one pixel consists of one switching element, one display electrode, one signal line, and one scanning line, so pixel defects include switching element failure, The disadvantage is that if any one of the signal lines and scanning lines is broken, the pixel will not operate and the image will be damaged.

In particular, active matrix liquid crystal displays have the characteristic of being able to display large amounts of data, and many attempts have been made to utilize this characteristic to display televisions. In this case, the number of pixels reaches several hundred thousand, and it is extremely difficult to manufacture the switching elements, signal lines, and scanning lines that make up the pixels without defects.

The purpose of the present invention is to prevent an entire pixel from becoming an image defect due to a defect in a switching element, signal line, scanning line, etc. that constitutes an active matrix substrate of an active matrix liquid crystal display, and even if there is a defect, only a part of one pixel exists. The object of the present invention is to provide a structure that makes image defects less noticeable.

(Means for Solving the Problems) According to the present invention, one pixel formed on an active matrix substrate having switching elements has a plurality of display electrode groups, scanning lines, and signal lines distributed within one pixel. a plurality of switching elements, at least one of the scanning line and the signal line is composed of a plurality of lines, and the display electrode is connected to the scanning line and the signal line through each switching element. be.

(Function) The present invention minimizes pixel defects by dividing one pixel into a plurality of parts, and by configuring a plurality of switching elements in an equally distributed arrangement, all the switching elements for one pixel are Reduces the probability of defects.

(Example) Examples of specific arrangement configurations will be described in detail below with reference to the drawings.

(Example 1) FIG. 1 is a diagram showing a part of a plan view of an active matrix substrate for explaining a first example of the present invention.

This embodiment is an example in which one pixel 15 is divided into four. Mainly, 4
The display electrode 11 includes four display electrodes 11, four switching elements 12, two signal lines 13, and two scanning lines 14. The pixel pitch is 250μm and the display electrode is 100μ, x
A combination of four display electrodes 11 each having a diameter of 105 μm was used to form one pixel. The switching element 12 is an amorphous silicon thin film transistor with a channel length of 8μ.
The m channel width was 80 μm. Further, the line widths of the signal lines and scanning lines were set to 10 μm. Furthermore, in order to reduce the defect occurrence rate of thin film transistors, the thin film transistors were equally distributed within one pixel as shown at 12 in FIG.

Comparing the results of displaying one pixel with four display electrodes of 100 μm x 105 μm in IJ Waxnel in which the present invention is implemented with the conventional No4Nel displaying one pixel with one display electrode of 215 μm x 220 μm. As a result, the display characteristics were almost the same. This is because the charging current required to switch the liquid crystal is smaller as the display rat pole is smaller, so the channel width of the transistor is about 50 μm compared to the conventional 200 μm. This shows that comparable display characteristics can be obtained even with a channel width of 100 μm.

In addition, the probability that one pixel would become defective due to a defect in a thin film transistor was 0.05% in the past, but in the present invention, all four transistors for one pixel were defective, making the entire pixel defective. is less than 0.00001 υ,
None of the 450,000 pixels were found.Although the display defects of the grass pixels occur to the same extent, the area is miniaturized and the information display for each pixel works normally for the same number of pixels. Because of this, it does not appear as a noticeable defect.

When the present invention is implemented, the defects are not noticeable because the thin film transistors are arranged in a distributed manner, so it is difficult for the four transistors for one pixel to generate defects at the same time.
This is because the channel length of the transistor has been shortened compared to the conventional value, which reduces the defect occurrence rate, and because each pixel has multiple signal lines and scanning lines, the occurrence of defects due to disconnections and the like can also be reduced.

By the way, the structure of an active matrix substrate in which switching elements are distributed is shown in FIG. 2(a).

Examples (b) and (e) are possible, in which the switching elements 22 are arranged at the positions shown in the figures. One pixel 25 is a group of display electrodes 21 indicated by diagonal lines. In the figure, 23 indicates a signal line, and 24 indicates a scanning line.

(Example 2) FIG. 3 is a diagram showing a part of a plan view of an active matrix substrate for explaining another example of implementing the present invention.

In this embodiment, one pixel 35 is divided into two, and two display electrodes 3
1 group, 2 switching elements 32 and 2 scanning elements?
The structure is mainly composed of A34 and one signal line 33. This is an effective method when the aspect ratio of one pixel differs by about twice. The size of one pixel is 15011m x 300
μm, and the display electrode has 120. Two display electrodes 31, 31 with a size of bX125#+ were used. The switching element 32 has a channel length of 10 mm and a channel width of 100 μm.
Amorphous silicon thin film transistors were used. Further, the line widths of the signal line 33 and the scanning line 34 were set to 15 μm. Furthermore, in order to reduce the defect occurrence rate of thin film transistors, the arrangement of the switching elements 32 within one pixel is dispersed as shown in FIG.

A display electrode 31, a signal line 33, and a scanning line 34 are connected to the thin film transistor switching element 32, respectively.

As a result of implementing the present invention, not a single pixel out of 75,000 pixels became defective, and the probability of defect occurring was less than 0.001, compared to 0.05% in the past. The probability could be reduced. Therefore, as in Example 1, pixel defects are caused by the effect of increasing the number of switching elements, the effect of distributing the switching elements, the effect of reducing the size of the switching elements, the effect of using multiple scanning lines, and the effect of dividing the display electrode. It was confirmed that the synergistic effect of each effect with the other effects can significantly reduce the amount of carbon dioxide.

In Examples 1 and 2 above, an amorphous silicon film transistor was used as a switching element, but the switching element is not limited to this, and thin film transistors or diodes made of other semiconductor thin films such as polysilicon thin films, or metal-insulating film-metal (metal-insulating film-metal) This method is also effective even when a nonlinear switching element such as an MIM (Multi-dimensional Imaging Mechanism) element is used.

(Effects of the Invention) As described above, in the present invention, one pixel is divided into a plurality of parts, a plurality of display electrodes and switching elements, at least one of which is 'M', and several scanning lines, signal lines, etc. Since the structure is such that one pixel is driven at the same time and the switching elements are dispersed within one pixel, the probability that one pixel as a whole becomes a display defect can be significantly reduced.

In the present invention, when the aspect ratio of one pixel is large, dividing the pixel in the long side direction and creating a structure having the above configuration is an effective structure because the conventional manufacturing process can be used without modification.

The size of one pixel that is usually used is 2508 m x 250 μm or 150 μm x 300 m, as described in the above example.
Whereas the size of the switching element for driving the display electrode of the pixel, the width of the scanning line, and the width of the signal line are about 15 μm or less for one pixel. Therefore, the size of the defects caused by dust and the like is sufficiently larger. Therefore, if we create a structure in which one pixel can be divided into multiple parts and driven, the defective part will be a display defect in the middle part of one pixel, but the other parts will operate normally, so the display will not work. This will prevent the quality from deteriorating too much. In addition, if the switching elements connected to the divided display electrodes, the scanning lines for driving, and the signal ≧J- are separated by a distance larger than the size of defects caused by store dust, etc., the divided display electrodes can be separated. This has the effect of extremely reducing the probability that one entire pixel will become defective at the same time.

[Brief explanation of drawings]

FIG. 1 is a plan view showing a part of an active matrix substrate showing the first embodiment of the present invention, and FIG. 2 (, ), (
b) and (C) are plan views showing examples of the arrangement of switching elements, FIG. 3 is a plan view showing a part of an active matrix substrate showing a second embodiment of the present invention, and FIG. 4 is a plan view showing an example of the arrangement of switching elements. FIG. 3 is a plan view showing a part of the matrix substrate. In the figure, 11, 21, 31 are display electrodes, 12°22, 32 are switching elements, 13, 23, 3
3 is a signal line, 14, 24, 34 is a scanning line, 15
, 25 and 35 each represent one pixel. - 15-1 pixels (CL) (b) (C)
21 - Display electrode 22 - Switching element 33 - Signal line 34 - Scanning line 35 - 1 pixel

Claims (1)

[Claims] (1) In an active matrix liquid crystal panel having switching elements, one pixel formed on an active matrix substrate is composed of a plurality of display electrode groups, a scanning line, a signal line, and a plurality of switching elements, and the scanning line and the signal A liquid crystal matrix panel characterized in that at least one of the lines is composed of a plurality of lines, and each of the display electrodes is connected to a scanning line and a signal line through respective switching elements distributed within one pixel.