JPH0713197A - Matrix type wiring substrate and liquid crystal display device formed by using the same - Google Patents

Abstract

PURPOSE:To provide the substrate which enables the repair of the display defects in intersected points even if there are plural shorting points on the same signal line and necessitates shorter turning around of repair wirings by forming the wirings for repair at each intersected point in the intersected points of display pixel regions. CONSTITUTION:The repair wirings 15 are formed of thin films, etc., consisting of aluminum, etc., in the same manner as for signal lines 2a, 2b and both ends are formed on the upper layer of the signal line 2a so as to overlap partly on the signal line 2a. The repair wiring 2a bypasses the intersected point 16. The signal line 2a is cut at both ends of the shorting part to break down the insulating film in the overlapping part of the wiring 15 for repair and the signal line 2a if the signal lines 2a, 2b are shorted in the intersected point 16. The signal line 2a is thus connected via the repair wiring 15. Consequently, input signals are applied form the signal lines 2a, 2b in an ordinary manner to the TFT 12 corresponding to the intersected point 16 and further the respective TFTs on the signal lines 2a, 2b.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a matrix type wiring board used for a matrix type display device, a CCD device and the like and a liquid crystal display device using the same. More specifically, the present invention relates to a matrix type wiring board provided with repair wiring for repairing a short circuit (short circuit) generated at the intersection of signal lines arranged in a matrix, and a liquid crystal display device using the same.

[0002]

2. Description of the Related Art FIG. 4 is an explanatory view of a matrix type wiring board having a conventional repair wiring. In FIG. 4, 1
Is a glass substrate on the surface of which liquid crystal driving elements such as TFTs are formed, 2a and 2b are signal lines formed on the glass substrate 1, respectively, and 3 is a signal line 2a.
Or a signal input terminal for adding various signals to 2b, 4
Is a conventional repair wiring and is normally connected to the signal lines 2a and 2b because it is formed via an insulating film (not shown) made of a silicon nitride (SiN) film or the like. Absent. Reference numeral 24 denotes a display area of the liquid crystal display device, which is also called a display pixel area because it is composed of display pixels.

The repair wiring 4 includes a signal line 2a,
One or more loops are provided on the upper layer of 2b and outside the display pixel region 24.

In the liquid crystal display device, since the signal line 2a and the signal line 2b are usually formed with an insulating film between them, the input signals applied to them do not interfere with each other. However, if the signal line 2a and the signal line 2b are electrically short-circuited due to an abnormality in the insulating film at the intersection 5 in FIG.
Display defects occur in the pixels on a and 2b, and linear display defects appear vertically and horizontally in the display area 24.

In order to remove this electrical short, the following method has been conventionally used. That is, first, the wavy lines 6a and 6b in FIG. 4 are irradiated with laser light to electrically cut the signal line 2a from the intersection 5. Although the electrical short between the signal line 2a and the signal line 2b is removed by this, the signal input from the signal input terminal 3 does not reach the portion of the signal line 2a beyond the wavy line 6b, as it is. Will be left with defects. In order to solve this problem, laser light is further applied to the intersections 7a and 7b between the signal line 2a and the repair wiring 4 in FIG. Repair wire 4 and signal line 2 by laser light
The insulating film between a and a is destroyed, and the repair wiring 4 and the signal line 2a are electrically short-circuited. As a result, the input signal applied from the signal input terminal 3 wraps around the repair wiring 4 and reaches the portion of the signal line 2a that is ahead of the wavy line 6b, so that a normal display operation can be performed.

[0006]

However, for example, as shown in FIG.
If there are a plurality of short-circuited points on the same signal line such as the intersection 8a and the intersection 8b, if the signal line is laser cut to remove the short-circuit, the repair wiring 4 is used. The input signal cannot reach the signal line between the intersection 8a and the intersection 8b. Further, since the repair wiring 4 is formed so as to surround the display pixel region 24, a signal will be laid around for a long time during use, and there is a problem in that it is electrically disadvantageous in terms of impedance.

The present invention has been made in order to solve the above problem, and it is possible to repair a display defect at an intersection even when there are a plurality of short-circuited points on the same signal line, and to repair wiring. It is an object of the present invention to provide a matrix type wiring board which requires only a short wiring and a liquid crystal display device using the same.

[0008]

A matrix type wiring board of the present invention has two sets of signal lines intersecting each other on an insulating substrate, and the signal lines are respectively provided at the intersecting portions of at least one set of signal lines. A repair wiring that bypasses the line is provided, and both ends of the repair wiring are formed so as to overlap with the signal line through an insulating film.

Further, the liquid crystal display device of the present invention is a liquid crystal display device in which a liquid crystal material is sandwiched between two transparent substrates having an electrode film formed thereon, and at least one of the two transparent substrates has the above-mentioned structure. A matrix type wiring board is used.

[0010]

According to the matrix type wiring board of the present invention, since the repair wiring is formed at each intersection at the intersection of the display pixel regions, the short-circuited portions between the signal lines are on the same signal line. In addition, by cutting the signal line near each short point with a laser, etc. and destroying the insulating film at the intersection with the repair wiring with a laser etc. and welding the repair wiring and the signal line, the short points can be individually separated. Can be repaired. Further, since the repair wiring of the present invention bypasses only the extremely small intersections of the signal lines, there is almost no unnecessary electrical routing of the input signal, and the impedance does not increase. Therefore, when a liquid crystal display device is constructed by using the matrix type wiring board of the present invention as one of the boards, display unevenness due to an increase in impedance does not occur.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, a matrix type wiring board of the present invention will be described with reference to the drawings. FIG. 1 is an enlarged plan view of an essential part showing one of the display pixels of an embodiment of the matrix type wiring board of the present invention, and FIG. 2 shows repair wiring and signal lines of the matrix type wiring board of FIG. 1 by laser irradiation. 3 is a cross-sectional explanatory view showing the principle of connection of FIG. 3, and FIG. 3 is an explanatory view showing how to use the repair wiring of the matrix type wiring board of FIG. 1 when there are a plurality of short-circuited points in the same signal line. FIG. 1 shows a matrix wiring and pixels formed on the surface of a glass substrate 1, for example, as an example of the structure of the matrix wiring substrate. 2a and 2b are the same signal lines as shown in FIG. 4, 9 is the signal line 2
a is a gate electrode integrally formed with a, 10 is a source electrode integrally formed with the signal line 2b, 11 is a drain electrode, and together with the gate electrode 9 and the source electrode 10 constitutes a TFT 12 which is a switching element of each pixel. Reference numeral 13 denotes a pixel electrode made of ITO or the like for applying a voltage to a display material such as a liquid crystal material, and 14 denotes an additional capacitance added between the pixel electrode 13 and the signal line 2a to improve display performance. An electrode (hereinafter referred to as a Cs electrode), and a TFT
12 and the pixel electrode 13 constitute one display pixel. 15
Is a repair wiring and is electrically insulated from the signal lines 2a and 2b by an insulating film (not shown).

The repair wiring 15 is formed of a thin film made of aluminum or the like like the signal lines 2a and 2b, and both ends thereof are covered with an insulating film to form the signal line 2a.
Is formed in the upper layer of the signal line 2a so as to partially overlap with (see C in FIG. 1). The repair wiring 15 bypasses the intersection 16 and is usually about 100 μm at the longest. Specifically, for example, the width is about 10 to 20 μm, which is about the same as the signal lines 2a and 2b, and the length A of each arm is 20.
The shape and size are not particularly limited, though the length is about 30 to 30 μm and the length B of the body is about 30 to 40 μm.

Further, the repair wiring 15 may be formed of a metal thin film such as chromium or ITO.

Further, a silicon nitride film or a silicon oxide film is adopted as an insulating film formed between the repair wiring 15 and the signal line 2a, and plasma CVD is used.
It is formed to a thickness of about 0.2 to 0.4 μm by a method such as a method.

The matrix type wiring board of the present invention is characterized in that at least one signal line is provided with a repair wiring 15 that bypasses the intersection at each intersection 16 via an insulating film.

That is, the intersection of the signal lines 2a and 2b
At 16, if the signal lines 2a and 2b are not short-circuited, the normal display operation is performed in the state of the wiring structure of FIG.
If the signal lines 2a and 2b are short-circuited at the intersection 16, the signal line 2a is cut on both sides of the short-circuited portion, and the insulating film in the overlapping portion between the repair wiring 15 and the signal line 2a is destroyed. , The signal line 2a is connected through the repair wiring 15. As a result, the TFT 12 corresponding to the shorted intersection 16 and each T on the signal lines 2a and 2b.
An input signal is normally applied to the FT from the signal lines 2a and 2b, and the display defect is eliminated by the switching action of the TFT.

Although the repair wiring 15 is formed in the upper layer of the signal line 2a in the present embodiment, the same effect can be obtained even if it is formed in the lower layer.

Next, referring to FIGS. 1 to 3, for a method of repairing a short-circuited portion when an abnormality occurs in the insulating film at the intersection 16 of the signal lines 2a and 2b and the signal lines 2a and 2b are electrically short-circuited. While explaining concretely.

First, the vicinity of the shorted intersection 16 of the signal lines 2a, for example, the wavy line portions 17a and 17b are cut by the irradiation of laser light to separate the shorted portions between the signal lines. Next, in order to repair the disconnection of the signal line 2a,
Overlapping portions 18a, 18 of the signal line 2a and the repair wiring 15
b is irradiated with laser light, and the signal line 2a and repair wiring
Connect 15 electrically. For example, as shown in FIG. 2, electrical connection can be obtained by destroying the insulating film 25 existing between the signal line 2a and the repair wiring 15 by irradiation with laser light 26.

The length of the repair wiring 15 is 100 μm at the longest.
Since there is only a degree, there is almost no unnecessary routing of the input signal. Further, even when a plurality of short circuits occur on the same signal line 2a as at the intersections 19a and 19b in FIG. 3, the wavy lines 20a and 20b and the wavy lines 21a and 21b of the signal line 2a are also included.
The laser light is cut, and the display defects can be individually repaired by connecting the overlapping portions 22a, 22b and 23a, 23b with the repair wiring 15 by irradiating laser light.

Further, if the repair wiring 15 is formed in the same step as the formation of the Cs electrode 14, the manufacturing cost is hardly increased.

After forming a protective film such as silicon nitride and an alignment film such as polyimide on the surface of the matrix type wiring board constructed as described above, it is opposed to the other insulating substrate provided with the electrode film and the alignment film. By filling the gap between the two substrates with the liquid crystal material, an active matrix type liquid crystal display device is obtained. In this liquid crystal display device, even a pixel on a restored signal line can obtain a driving voltage similar to that of other pixels, and thus display performance can be improved.

[0023]

According to the present invention, the matrix type wiring board can be repaired even when a plurality of short-circuited points are generated in the same signal line. Therefore, the yield can be further improved. Moreover, since there is no unnecessary wiring, there is almost no difference in impedance from other signal lines. Therefore, if a liquid crystal display device is constructed using the matrix type wiring board, the display performance can be improved.

[Brief description of drawings]

FIG. 1 is an enlarged plan view of an essential part showing one of display pixels of an embodiment of a matrix type wiring board of the present invention.

2 is a cross-sectional explanatory view showing a principle of connection between a repair wiring and a signal line of the matrix type wiring board of FIG. 1 by laser irradiation.

FIG. 3 is an explanatory view showing a method of using the repair wiring of the matrix type wiring board of FIG. 1 when the same signal line has a plurality of short-circuited portions.

FIG. 4 is an explanatory diagram showing how to use a repair wiring of a conventional liquid crystal display device.

[Explanation of symbols]

 1 glass substrate 2a signal line 2b signal line 15 repair wiring 16 intersection 25 insulating film

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Masayuki Yokomizo, 997 Miyoshi, Nishigoshi-cho, Kikuchi-gun, Kumamoto Inside Advanced Display Co., Ltd. (72) Kenichi Niki, 997 Miyoshi, Nishigoshi-cho, Kikuchi-gun, Kumamoto・ In the display

Claims (2)

[Claims] 1. A matrix-type wiring board having two sets of signal lines intersecting with each other on an insulating substrate, and repair wiring for bypassing the signal lines at least at the intersecting portions of at least one set of signal lines. Is provided,
A matrix type wiring board in which both ends of the repair wiring are formed so as to overlap the signal line with an insulating film interposed therebetween. 2. A liquid crystal display device comprising a liquid crystal material sandwiched between two transparent substrates having electrode films formed thereon, wherein the matrix type wiring substrate according to claim 1 is provided on at least one of the two transparent substrates. A liquid crystal display device using the.