JPH01292320A - Picture display panel - Google Patents

Abstract

PURPOSE:To obtain a large size picture having uniform a rate of aperture contg. no useless area by giving no redundancy of a picture element driving section to picture elements adjacent to bonded parts of substrates to each other provided with a picture element electrode, but giving redundancy picture elements other than those in the bonded parts. CONSTITUTION:Substrates 1L, 1R provided with picture element electrodes are bonded at a bonded part 3, and each electrode 4 is arranged with a same shape, same size, and same pitch while regulating a minimum breadth S3 permitting the arrangement of the picture element electrode to the same dimension as the gap S4 of all picture element electrodes 4 at near the bonded part 3. Thereafter, picture elements driving sections 5 for driving the electrodes 4 are arranged to the gaps of each electrode 4 with a same shape, same size, and same pitch on the substrates 1L, 1R, within a range of each substrate. Then, there remains still spatial margin in picture elements other than those adjacent to the bonded part 3 even if a driving section 5 is arranged to the gap between the electrodes 4. A prepn. yield of the substrate 1 is improved by constituting a picture display panel by giving redundancy of picture element driving by arranging a picture element electrode driving section 6 to said marginal zone permitting driving of the electrode 4 by a driving section 6 even if a driving section 5 is not driven normally.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention mainly relates to the structure of an image display panel that enables large screen display by joining a plurality of display panels.

[Conventional technology]

As an example of the conventional technology of assembling a plurality of substrates with pixel electrodes to form a large screen display panel,
There is a description in Publication No. 91029.

In this liquid crystal panel, at least one of the electrode-attached substrates is composed of a plurality of substrates, and these substrates are joined at the side surfaces to form a large composite substrate. After that, the structure is such that a liquid crystal is sandwiched between the composite substrate and the other substrate. Until now, it was thought that it would be difficult to manufacture large display panels due to manufacturing equipment, yield, etc., and it would be difficult to manufacture large single substrates with pixel-type electrodes, but with this technology,
It is also possible to obtain a large display panel with an area about four times that of the electrode-equipped substrate.

In addition, as display panels become larger, the issue is how to increase the yield of panels, and it is important to provide redundancy to each pixel, according to Nikkei Electronics, 410 (
December 15, 1986), pages 193-210.

[Problem to be solved by the invention]

When substrates with pixel electrodes are bonded together at their side surfaces using the first conventional technique, from the viewpoint of forming the bonding surface of each substrate and ensuring the required width for wiring to each pixel electrode, the pixel at the bonding portion l The electrode spacing becomes wider than the pixel electrode spacing that can be realized in other parts. Therefore, in order to keep the size of the pixel electrodes and the pitch between the pixel electrodes constant, the pixel electrode spacing at the joint must be applied to other parts, so it is not used in other parts other than the joint. This results in wasted area. That is, a high aperture ratio can be obtained without the joint, but with the joint, the aperture ratio of the portion other than the joint is suppressed by the low aperture ratio of the joint.

Further, according to the second conventional technique, it is estimated that a display panel with a relatively large screen can be formed at a high yield, but this is still not sufficient, and when manufacturing a display panel with an even larger screen, it is necessary to It is necessary to use these conventional techniques together.

An object of the present invention is to obtain a large-sized image display panel that has a uniform aperture ratio and has no wasted area.

[Means for solving the problem] The above purpose is not to add redundancy to the pixel drive unit to pixels adjacent to the joint between substrates with pixel electrodes, but to add redundancy to pixels other than the joint. This is achieved by:

[Effect]

Since the pixel at the junction part does not have redundancy in the pixel driving section, one pixel can be configured with a smaller area than pixels other than the junction part to which redundancy is added.

The resulting gap between the junction pixels is used as the area required for the junction. The number of pixels at the junction is very small compared to the total number of pixels, and redundancy is added to most of the pixels, so a high yield can be expected. Furthermore, since redundancy is not added at the joint, the aperture ratio can be increased, so there is no need to worry about the overall aperture ratio being kept low by the aperture ratio of the joint.

〔Example〕

Hereinafter, the present invention will be explained using an example in which the present invention is applied to an active matrix type liquid crystal display panel.

FIG. 1 is a schematic front view of an image display panel to which the present invention is applied;
The figure is a sectional view of an image display panel according to an embodiment of the present invention using a liquid crystal element as an image display element.

In FIGS. 1 and 2, the pixel electrode-attached substrate 1z, IJ
I is joined at the joining part 3 to form -2 large-sized substrates. 4 is the display element of each pixel (liquid crystal element in the example in Figure 2)
5 is a first pixel drive and wiring section that drives each pixel electrode 4; 6 is a first pixel drive and wiring section that drives the pixel electrode 4 when there is an abnormality in the pixel drive and wiring section 5; 2 is a pixel drive and wiring section, 7 is a common electrode, 8 is an upper substrate, and 9 is a liquid crystal.

Generally, the wiring portions and the pixel drive portions 5 and 6 are often opaque, and do not overlap much with the pixel drive electrodes 4 that contribute to display. From the viewpoint of appearance, it is preferable that the pixel drive electrodes 4 that contribute to display are all arranged in the same shape, the same size, and at the same pitch, and that the gaps between them are as small as possible. on the other hand,
In the vicinity of the junction 3 between the two substrates IL and IR with pixel drive electrodes, the pixel drive electrode 4 and the pixel drive and wiring section 5 are located at a certain width 83, taking into account the difference in level caused by joining and the position of the joint. , 6 cannot be placed. Therefore, as shown in FIG. 1, the minimum width 83 in which the pixel electrodes 4 can be arranged near the joint 3 is set to be the same size as the gap S4 between all the pixel electrodes 4, so that each pixel electrode 4 has the same shape and the same size. Arrange with the same size and pitch.

The next best thing is the first pixel driving section 5 (
The portions hatched with diagonal lines downward to the right) are arranged in the gaps between the pixel electrodes 4 in the same shape, the same size, and the same pitch within each pixel electrode-equipped substrate IL. Then, even if the first pixel driving section 5 is disposed in the gap between each pixel electrode 4 in pixels other than the pixels adjacent to the joint section 3, a spatial margin of 1 still remains. A second pixel electrode drive unit 6 is arranged in the margin area, and the pixel drive unit 6 is arranged so that the pixel drive electrode 4 can be driven by the second pixel drive unit 6 even when the first pixel drive unit 5 does not operate normally. By adding redundancy to the structure, the aim is to improve the manufacturing yield of substrates with pixel electrodes. A second pixel drive unit is not provided in the pixel adjacent to the joint part 3, but the number of pixels adjacent to the joint part 3 is small compared to the total number of pixels in the display panel, and a defect in the pixel drive part in this part This has little effect on the overall yield of the display panel.

Further, from the embodiment shown in FIG. 1, it is clear that the pixel electrodes, pixel drive sections, wiring sections, etc. of the substrates IL and IR with pixel electrodes are arranged in a horizontally symmetrical relationship with respect to the joint section 3. .

As described above, according to the embodiment shown in FIG. 1, the pixel electrodes effective for display can be arranged in the same shape, the same size, and at the same pitch, and the pixel electrodes can be kept as large as possible, resulting in a good appearance. Moreover, by providing redundancy to the pixel drive sections other than those near the junction, there is an advantage that an improvement in manufacturing yield can be expected.

FIG. 3 shows an example of an electrical equivalent circuit applied to an active matrix type liquid crystal display panel as the display panel of the embodiment shown in FIG. LCij (1tj=1t2.
3...) is a liquid crystal cell, TAij is a first pixel drive transistor, TBij is a second pixel drive transistor, D
Aj is a first drain bus, DBj is a second drain bus, GLi and GRi are gate buses, and 7 is a common electrode.

The operation of the embodiment shown in FIG. 3 will be explained by taking up a pixel including the liquid crystal cell LC12. The liquid crystal cell LC12 is connected to the first pixel transistor TA12 and the second pixel transistor TB12 by a selection signal applied to the gate bus GLI.
While on, the liquid crystal cell LC12 is driven by the signals applied to the first drain bus DA2 and the second drain bus DB2, respectively. Gate bus GL1
While a non-selection signal is applied to , both the first pixel transistor TA12 and the second pixel transistor TB12 are turned off, regardless of the signals applied to the first drain bus DA2 and the second drain bus DB2. The signals while the gate bus GL1 was selected are held and displayed.

At this time, for example, the first drain bus DA2 or the first
Even if the pixel transistor TA12 is disconnected, the second drain bus DB2 and the second pixel transistor 'l'
A signal can be applied to the liquid crystal cell LC12 through 1312.

Furthermore, even if the second drain bus 1)B4 and the second pixel transistor TB12 are disconnected, if the first drain bus DA2 and the first pixel transistor TA12 are normal, a signal can be applied to the liquid crystal cell LC12. can. That is, if either the first or second one operates normally, the liquid crystal cell LC12 can be driven.In other words, since there is redundancy, the defect rate of the substrate with pixel electrodes is reduced, and an improvement in yield can be expected. .

In the embodiment shown in FIG. 3, in the pixel adjacent to the junction 3, the second drain bus and the second pixel transistor are omitted, and that part is used as the part required for the junction. Since the pixels adjacent to the junction 3 do not have a second pixel driver, the defect rate is higher than other pixels that have a second pixel driver, but compared to the total number of pixels. Since the number of pixels that do not have a second pixel driving section is small, there is little effect on the yield of the substrate with pixel electrodes.

FIG. 4 is a schematic front view of the pixel electrode-attached substrate junction and its surrounding area in another embodiment of the present invention. A major difference from the embodiment shown in FIG. 1 is that the shape of the pixel electrode 41 adjacent to the joint portion 3 is deformed while maintaining approximately the same area as the other pixel electrodes 4. When applied to a liquid crystal display panel as a display panel, it is necessary to increase the transmittance of the panel from the viewpoint of brightness, that is, to make the size of the pixel electrode as large as possible. However, in the pixel adjacent to the joint part 3, simply removing the second pixel drive and wiring part may not be sufficient for the area required for the joint part, and it becomes necessary to shave the pixel electrode part. If this continues, pixel electrodes other than those adjacent to the junction must be removed in order to ensure uniformity of the display panel, resulting in a dark display. Therefore, in FIG. 4, the shape of the pixel electrode adjacent to the junction is different from that of other pixels, but the area is the same, thereby minimizing the influence on the appearance and obtaining a bright display. In this way, the size of the pixel electrode is increased by changing the pixel shape of the pixel adjacent to the junction (for example, in the equivalent circuit of FIG. 3, the gate bus GL i +
Since G Rr terminates before the junction 3, this can be easily realized by using the wiring regions of these gate buses as pixel electrode regions only in pixels adjacent to the junction.

Also, the second pixel! Depending on the size of the lX moving part, it is also possible to change the pixel shape of the pixel adjacent to the junction part and make the pixel electrode size the same as that of other pixels.

FIG. 5 is a schematic front view of four substrates with pixel electrodes and their surrounding areas according to another embodiment of the present invention. In addition to the first pixel drive unit 51, each pixel is provided with three second pixel drive units 61, and all the second pixel drive units are connected to the four pixels in the portion where the corners of the four substrates with pixel electrodes meet. By removing the two second pixel drive parts and changing the shape of the pixel electrodes in the pixels adjacent to each other on the other junctions, the area of each pixel electrode was kept constant, similar to the embodiment shown in FIG. This is an example.

In the embodiments described above, the area of each pixel drive electrode is made constant, and the aim is to achieve uniformity in resolution and brightness.

However, depending on the joining method number, there may be cases where a larger area is required for the joining portion. In that case, the pixels near the junction will be made larger and the resolution of the junction will be slightly degraded, but the aperture ratio (value obtained by dividing the area of the pixel electrode part by the area of the pixel pitch) will be kept constant and the uniformity of brightness will be maintained. By applying the method of maintaining this to the previous embodiment, the influence on the appearance of the display panel can be minimized.

〔Effect of the invention〕

As described above, according to the present invention, the yield of display panels can be improved by providing redundancy to most pixels, and the area required for bonding is eliminated by eliminating redundancy in pixels adjacent to the bonding area. This has the effect of keeping the aperture ratio of the pixel adjacent to the junction part, which tends to be taken as a problem, the same as the aperture ratio of other pixels, thereby making it possible to obtain a bright image display panel with uniform display panel brightness.

[Brief explanation of the drawing]

FIG. 1 is a schematic front view of the pixel electrode-equipped substrate joint part and its surrounding area of an image display panel as an embodiment of the present invention;
FIG. 2 is a sectional view of an image display panel as an embodiment of the present invention, FIG. 3 is an equivalent circuit diagram of an image display panel as an embodiment of the present invention, and FIGS. 4 and 5 are respectively FIG. 7 is a schematic front view of the pixel electrode-equipped substrate joint portion and the vicinity of the peripheral portion of the image display panel as another example of the present invention. 1'! ? , 1L...Substrate with pixel electrode 3...Joint portion 4, 41, 42, 43...Pixel electrode 5.6...
- Pixel drive and wiring section 51, 61... Pixel drive section 7... Opposing common electrode 8... Upper substrate 9... Liquid crystal GRi, G
L+...Gate bus DAj, DBj...Drain bus TAIj, TB
ij...Pixel transistor LCij...Liquid crystal cell IL IR Atsushi 3 Diagram IL 1+2 5
figure

Claims (1)

[Claims] 1. A pixel display panel in which a plurality of substrates with pixel electrodes, which are formed by regularly arranging pixel electrodes with pixel drive units, are joined together at their sides to form a single substrate. An image display panel characterized in that redundancy is provided in pixel drive units of pixels other than pixels located adjacent to the side surface joint portion of the substrate with pixel electrodes.