JPH04331920A - Liquid crystal display device - Google Patents

Abstract

PURPOSE:To reduce the occupation area of a bus correction line and mechanically and chemically protect the bus correction line. CONSTITUTION:Liquid crystal is charged between a TFT substrate 10 and an opposite substrate 30, which are isolated and arranged at a specific interval by a seal part 40. The correction line 16 for correcting disconnection trouble of drain buses 12a-12n, and 13a-13n is formed in the seal part 40 by the same process as the formation of the drain buses 12a-12n, and 13a-13n, and at the intersection parts of the drain buses 12a-12n, and 13a-13n and the correction line 16, the drain buses 12a-12n, and 13a-13n are connected by jumping trough a metallic layer formed by utilizing, for example, the gate electrode formation of TFTs. A disconnected bus and the correction line 16 are connected by irradiating the reverse surface of the TFT substrate 10 with infrared laser light, so the correction line 16 can be arranged in a dead space.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device, and more particularly to a technique for repairing a drain disconnection in an active matrix liquid crystal display device.

0002

2. Description of the Related Art A liquid crystal display device for TV or the like equipped with a thin film transistor has a gate electrode, an insulating film, an amorphous silicon layer, an ion-doped amorphous silicon layer, a source electrode, and a drain electrode formed in sequence on a glass substrate. Approximately 300,000 to 1,500,000 pixel display areas each having an electrode connected to a display electrode are formed on a substrate to perform a predetermined display. When manufacturing this liquid crystal display device,
In particular, there is a problem in that a drain bus or a gate bus is disconnected due to the attachment of dust or the like during the manufacturing process of a substrate for forming a thin film transistor, and a predetermined signal voltage is not applied to the thin film transistor of the disconnected bus, resulting in a defective product. In order to solve this problem, a method is known in which a repair line for repairing each bus is provided on the board in advance to regenerate a broken bus.

A technique for repairing a drain disconnection in an active matrix liquid crystal display device will be described with reference to FIG. This figure is a schematic plan view of a liquid crystal display device showing a thin film transistor, a pixel, and an auxiliary capacitor in an equivalent circuit. ), this drain bath (5
The respective terminals (54a) to (52n) of 2a) to (52n)
4n), a plurality of gate buses (56a) to (56n) orthogonal to the drain buses (52a) to (52n), drain buses (52a) to (52n) and gate buses (56a) to
(56n), and are arranged at each intersection of the drain bus (52a).
) to (52n), a thin film transistor (58ij) whose drain and gate are connected to the gate buses (56a) to (56n), respectively, a liquid crystal cell (60ij) connected to the source of the thin film transistor (58ij), and an auxiliary capacitor (62ij). ) is expressed. In this liquid crystal display device, a U-shaped drain correction line (64) is formed at the periphery of the substrate (50).

In the illustrated liquid crystal display device in which the potentials of the drain buses (52a) to (52n) are controlled by the terminals (54a) to (54n), as described above, for example, a disconnection occurs at point a of the drain bus (52i). When a failure occurs, the liquid crystal cells (60ij+1) to (60in) become unable to display. In this case, the insulating layer (not shown) at the two intersections of the drain bus (52i) and the drain correction line (64) is removed, for example, by laser irradiation, and the drain bus (52i) and the drain correction line (64) are removed. When melted and connected, liquid crystal cells (60ia) to (60ij)
is potential-controlled by the original drain bus (52i), and the liquid crystal cells (60ij+1) to (60in) are potential-controlled via the drain repair line (64), so that the drain bus (52i) is repaired. Note that by forming a plurality of drain correction lines (64) in parallel, it is possible to cope with a plurality of drain disconnections.

[0005]

SUMMARY OF THE INVENTION In order to downsize the liquid crystal display panel, the inventor of the present invention placed the above correction line within the liquid crystal display area. However, in such a structure, when the line breakage that is the problem in the present invention occurs and is repaired using a laser, the broken line is selected and a predetermined signal voltage is applied, so that the line breakage, which is the problem in the present invention, is selected and a predetermined signal voltage is applied. There was a problem that display quality deteriorated due to stray capacitance between the two.

In order to solve this problem, a correction line had to be formed outside the liquid crystal display area, that is, on the exposed area of the substrate (50) on the thin film transistor side, as shown in FIG. However, since the repair line (64) is formed on the exposed area of the substrate outside the display area, there is a risk that the drain repair line (64) may be corroded or disconnected by flux used in the soldering process, for example. Furthermore, there was a risk that the drain correction line (64) would be disconnected due to a minor handling error. Furthermore, T
This has the disadvantage that the FT substrate size becomes large. The present invention has been made in consideration of the effects on the liquid crystal display device during protection and repair of the drain repair line described above.

[0007]

[Means for Solving the Problems] The main feature of the present invention is that a correction line is formed in a liquid crystal sealing portion which is a dead space on a TFT substrate.

[0008]

[Operation] Since the repair line is formed in the liquid crystal sealing portion on the TFT substrate, the TFT substrate size is reduced and the weather resistance of the repair line is improved. In addition, the functions of the liquid crystal display device are protected from gas generation and thermal shock during the repair process.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIGS. 1 to 5. Note that FIG. 1 is a schematic plan view of the embodiment, and FIG. 2 is a side view. Further, FIG. 3 is an enlarged cross-sectional view of the vicinity of the intersection of the drain correction line and the drain bus, and FIGS. 4 and 5 are cross-sectional views of the vicinity of the intersection of the drain correction line and the drain bus before and after the drain restoration process. The structure and function of the display device itself, as well as the principle of repairing a drain disconnection, are the same as those of the conventional example, so a description thereof will be omitted.

Referring to FIGS. 1 and 2, the liquid crystal display device of the present invention has drain buses (12a) to (12n), (
13a) to (13n) and their terminals (14a) to (1
4n), (15a) to (15n), a TFT substrate (10) on which a drain correction line (16), a gate electrode (17), etc. are formed, a counter substrate (30), and a substrate facing these TFT substrates (10). The substrates (30) are arranged at predetermined intervals,
Sealing seal part (40) that seals the liquid crystal filled inside
It consists of Drain bath (12a) to (12n)
, (13a) to (13n) are TFTs as shown in the figure.
They are alternately led out to opposite sides of the substrate (10).

Referring to FIG. 3, the drain bus (12a) led out from the center of the TFT substrate (10) connects the first contact (20), the first metal layer (18), and the second contact (21). ), and is electrically connected to the drain terminal (14a) through the drain correction line (16), and is insulated from the drain correction line (16) by insulating layers (19), (22), and (23).

The first metal layer (18) is patterned in the vicinity of the drain correction line (16) when forming the TFT gate by chromium (Cr) sputtering, and the insulating layer (19) is made of SiNx or the like. A gate insulating film formed by CVD is used. The insulating layers (22) and (23) are made of amorphous silicon and SiNx, respectively, which were formed in the same way.
This layer was formed at the same time as the semiconductor active layer and passivation layer of the TFT. These insulating layers (
22) and (23) are formed to further ensure insulation between the drain correction line (16) and the first metal layer (18). Furthermore, first and second contacts (20) (2
1) The drain correction line (16) is formed by aluminum sputtering which forms the drain electrode and drain bus (12a) of the TFT. This drain correction line (
16) has a line width of approximately 50 μm.

As shown in FIG. 4, the above-mentioned drain correction line (16) is completely sealed by an adhesive sealing part (40) for adhering to the counter substrate. In this embodiment, since the width of the seal portion (40) is about 1 mm to 2 mm, it is possible to provide a plurality of correction lines (16). Further, in the present invention, the vertical arrangement of the drain correction line (16) and drain buses (12a) to (12n) and the buses to be corrected are not limited. From the figure, it is clear that the size of the TFT substrate (10) is reduced by the space for routing the drain correction line (16) compared to the conventional example.

Next, drain repair processing will be explained with reference to FIGS. 4 and 5. In a liquid crystal display device that uses a glass substrate as the base of the TFT substrate (10) and the counter substrate (30), the TFT substrate (10) and the counter substrate (30)
It is impossible to mechanically process the drain correction line (16) formed between YAG
Evaporation and melting of the processing target using an infrared laser such as is used.

Now, the glass substrate (1) of the TFT substrate (10)
When a high-energy infrared laser is irradiated from the back side of 1), the first metal layer (18) made of gate electrode material (chromium/molybdenum) and constituting the drain bus first melts, and the insulating layer (19) ( 22) and (23) sequentially evaporate explosively. When this evaporation reaches the drain correction line (16) and the drain correction line (16) starts melting, the surface tension of the molten metal causes the metal material of the first metal layer (18) to melt first. and alloyed with
The drain modification line (16) and the first metal layer (18) are electrically connected. This repair process is carried out within a very short time, and the presence of the sealing part (40) alleviates the gasification pressure and thermal shock, so that the function of the liquid crystal display device is not impaired.

In the present invention, as described above, since the correction line is arranged in the liquid crystal sealing part which is a dead space, the liquid crystal is injected after the counter electrode substrate and the TFT substrate are integrated or between the substrates. Laser modification is possible in the finished product, and the effect is great. Also, if you look at Figure 5 after laser correction, it looks like there is only one laser correction, but
If you want certainty in the correction, it is better to make corrections in multiple places. In the above-described embodiments, the explanation has been given to the repair of the drain bus that is likely to cause disconnection, but the present invention can also be used to repair not only the drain bus but also the gate bus.

[0017]

[Effects of the Invention] In the liquid crystal display device of the present invention, the drain or gate correction line is arranged and formed in the sealing part that separates the TFT substrate and the counter substrate at a predetermined interval and seals the liquid crystal filled inside. The size of the TFT substrate is reduced by the space for routing the drain correction line. Furthermore, since the repair line is hermetically sealed, mechanical strength and chemical resistance are improved.

[0018]

[Brief explanation of drawings]

FIG. 1 is a plan view of an embodiment of the present invention.

FIG. 2 is a side view of the embodiment.

FIG. 3 is an enlarged sectional view of the vicinity of the intersection of the drain correction line and the drain bus.

FIG. 4 is a cross-sectional view of the embodiment before drain repair.

FIG. 5 is a cross-sectional view of the embodiment after drain repair.

FIG. 6 is an equivalent circuit diagram of a liquid crystal display element explaining drain repair.

FIG. 7 is a plan view of a conventional example.

[Explanation of symbols]

10 TFT substrate 16 Drain correction line 30 Opposite board 40 Sealing seal part

Claims (3)

[Claims] Claim 1: A TFT comprising a thin film transistor and a display electrode whose potential is controlled by the thin film transistor.
A liquid crystal display device in which a gap between a substrate and a counter substrate having a counter electrode of the display electrode is filled with liquid crystal, characterized in that a correction line is arranged in a liquid crystal sealing part on a TFT substrate. Device. 2. The liquid crystal display device according to claim 1, wherein the correction line is a drain correction line. 3. The liquid crystal display device according to claim 1, wherein the drain correction line and the drain bus are connected by laser irradiation.