JPH0462523A - Matrix substrate and matrix type display device - Google Patents

Abstract

PURPOSE:To make the electric resistance of a corrected bus electric conductor small and stable even when an open circuit is corrected by a stand-by electric conductor by giving the stand-by electric conductor a fusion point nearby the fusion point of the bus electric conductor. CONSTITUTION:The same Ta with the stand-by electric conductor 3 is used for a gate bus electric conductor 2 and a source bus electric conductor 1 so that the fusion point of the stand-by electric conductor 3 is equal to that of the gate bus electric conductor 2. When the source bus electric conductor 1x where an open circuit is present is specified, intersection parts 4a and 4b of stand-by electric conductors 3 at both end parts of the defective source bus electric conductor 1x are irradiated with laser light and other energy from the side of a substrate 5 as shown by an arrow 23 and from the side of a substrate 20 as shown by an arrow 25. The defective source bus electric conductor 1x and stand-by electric conductor 3 are fused by the laser light irradiation to break the stand-by electric conductor insulating film 24 and base insulating film 7 between those electric conductors 1x and 3, thereby connecting the defective source bus electric conductor 1x and stand-by electric conductor 3 electrically as shown by a hatched part 22.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a matrix substrate and a matrix type display device having a function of correcting disconnections in bus wiring.

(Prior Art) CRTs have been mainly used for man-machine interfaces. However, in recent years, matrix-type display devices using liquid crystals or the like have been attracting attention as image display devices that can replace CRTs. A matrix type display device is desired to be fine and large.

In order to display fine images using a matrix type display device, the size of the picture elements that make up the matrix must be made very small (and it is necessary to use a very large number of picture elements.The number of picture elements increases. Accordingly, the total length of the bus wiring that functions as the scanning line and the signal line also increases.As the total length of the bus wiring increases, the bus wiring becomes more likely to be disconnected.

Moreover, as display devices become larger, the total length of bus wiring becomes longer, and it becomes increasingly difficult to manufacture bus wiring without disconnections.

(Problems to be Solved by the Invention) A matrix display device has been developed that has a function of correcting disconnections in bus wiring. FIG. 1A schematically shows an example of a circuit diagram of the matrix type display device. A large number of source bus lines 1 are provided in parallel, orthogonal to a large number of gate bus lines ga2 that are parallel to each other in one direction. The gate bus wiring 2 and the source bus wiring 1 intersect with each other with an insulating film interposed therebetween in a non-conducting state. A picture element electrode 12 is provided in each rectangular area surrounded by the gate bus wiring 2 and the source bus wiring 1, and a liquid crystal is sealed between the picture element electrode 12 and the counter electrode lO, and the picture element capacity jl16 is formed. Each picture element electrode 12 has T P T as a switching element.
(Thin Film Transistor) 1
1 is connected. A gate electrode 13 and a source electrode 14 of the TFT II are connected to a gate bus line 2 and a source bus line 1, respectively. The drain electrode 15 of TFTll is connected to the picture element electrode 12. A preliminary wiring 3 is provided around the outer periphery of a region where a large number of picture elements are formed. The preliminary wiring 3 crosses each gate bus wiring 2 and source bus wiring 1 via an insulating film in a non-conductive state.

In a matrix board having such a circuit, if a break occurs in the source bus wiring IX, for example, it can be repaired using the spare wiring 3.

As shown in FIG. 1A, there is a disconnection 4 in the source bus wiring IX.
If this occurs, at the intersections 4a and 4b that intersect with the spare wiring 3 at both ends of the defective source bus wiring IX,
A laser beam or the like is irradiated. By laser beam irradiation, the defective source bus wiring ix and the preliminary wiring 3 are melted, the insulating film between these wirings lx and 3 is destroyed, and the defective source bus wiring 1x and the preliminary wiring 3 are electrically connected. be done. By connecting at two places in this manner, the portions on both sides of the disconnection portion 4 of the defective source bus wiring 1x are electrically connected via the preliminary wiring 3.

However, when performing correction in this way, if the difference between the melting point temperature of the source bus wiring 1 and the melting point temperature of the preliminary wiring 3 is large, the defective source bus wiring 1x and the preliminary wiring at the intersections 4a and 4b may The electrical connection with 3 becomes unstable, and the following problems occur.

First of all, a reliable electrical connection between the defective source bus wiring 1x and the spare wiring Is3 cannot be obtained, and the connection resistance increases. The ability of the driver IC to supply signals to the pixel electrodes 12 via the source bus wiring 1 is designed assuming a normal load resistance of the source bus wiring 1. However, in order to drive the picture element electrode 12, the capacity is insufficient. A picture element formed by such a picture element electrode 12 has a different display state from a picture element formed by another picture element electrode 12 connected to the normal source bus wiring 1. Therefore, even if the repair is performed using the preliminary wiring 3 as described above, the disconnection portion 4 cannot be completely repaired.

Second, at the intersections 4a and 4b where unstable connections have been made, the faulty source bus wiring IX and the spare wiring 3 are electrically damaged due to electrical, thermal, or mechanical shocks or changes. may be in a non-contact state. In such a case, the display state will return to the state before the correction.

When the above-mentioned disconnection portion 4 occurs, a line defect occurs on the display screen. Since a line defect is a serious defect, a display device having a line defect becomes a defective product, leading to an increase in the cost of the display device. All of the above problems become more noticeable as the display device becomes larger. As mentioned above, as the display device becomes larger, wire breakage becomes more likely to occur, so the need to solve the above-mentioned problems becomes greater with larger display devices.

The present invention solves the above-mentioned problems, and an object of the present invention is to have a spare wiring for correcting a break in the bus wiring, and furthermore, even if the break is corrected using the spare wiring, the break is not corrected. It is an object of the present invention to provide a matrix substrate and a matrix type display device in which the electric resistance of bus wiring is low and stable.

(Means for Solving the Problems) The matrix substrate of the present invention has picture element electrodes arranged in a matrix on an insulating substrate, and rows in one direction between the picture element electrodes. A matrix substrate having scan lines and signal lines arranged at each end of at least some of the lines in at least one of the lines of the scan lines and the signal lines. The above object is achieved by providing a preliminary wiring which intersects with the line of the part through an insulating film, and the preliminary wiring has a melting point close to the melting point of the part of the line.

The matrix type display device of the present invention has a matrix substrate having the above configuration, thereby achieving the above object.

(Function) In the matrix substrate and matrix type display device of the present invention, both ends of at least one part of the bus wiring of at least one of the bus wiring formed on the insulating substrate and consisting of the scanning line and the signal line. In each part, the preliminary wiring intersects with an insulating film interposed therebetween. The preliminary wire has a melting point close to the melting point of the part of the wire.

If a break occurs in any of the bus wirings that the spare wiring intersects with, resulting in a defective bus wiring, the defective bus wiring and the two
At each of the two intersections with the two spare wirings, the defective bus wiring and the spare wiring are electrically connected by irradiation with laser light or the like.

The two preliminary wirings may be electrically connected to each other on the matrix substrate, or may be arranged so as to be connectable outside the matrix substrate. In the latter case, after the connection by the laser beam irradiation described above, the two preliminary wirings are electrically connected to each other at the portions arranged to be further connectable.

Both sides of the disconnected bus wiring are electrically connected via the spare wiring, and the defective bus wiring is repaired.

Since the spare wiring has a melting point close to the melting point of the defective bus wiring, the defective bus wiring and the spare wiring are reliably connected, the connection has low resistance, and furthermore, The resistance value does not change due to mechanical shock, changes, etc. The resistance of the defective bus wiring corrected in this way does not become extremely large as in the prior art example described above. Therefore, there is no possibility that the driver IC will run out of capacity.

(Example) The present invention will be described below with reference to an example. The circuit diagram of the matrix type display device of this embodiment is similar to that shown in FIG. 1A described in the prior art section. This embodiment will be described with reference to FIG. 1A.

The matrix substrate of this embodiment has picture element electrodes 12 wired in a matrix, and gate bus wires 2 and source bus wires 1 wired in a row at one time between the picture element electrodes 12. have The gate bus wiring 2 functions as a scanning line, and the source bus wiring 1 functions as a signal line. The gate bus wiring 2 and the source bus wiring 1 intersect with each other with an insulating film interposed therebetween in a non-conducting state.

A liquid crystal is sealed between the picture element electrode 12 and the counter electrode 10,
A picture element capacitor 16 is formed. Each picture element electrode 12 has
A TFTll is connected as a switching element.

The gate electrode 13 and source electrode 14 of TFT II are connected to the gate bus wiring 2 and the source bus wiring, respectively! I! Connected to 1. The drain electrode 15 of TFTII is connected to the picture element electrode 12. Large number of pixel capacitors 16 and TF
A preliminary wiring 3 is provided around the outer periphery of the region where Tll is formed. The preliminary wiring 3 intersects with the gate bus wiring 2 and the source bus wiring 1 via an insulating film in a non-conducting state.

Intersection 4 between source bus wiring 1 and spare wiring 3 in FIG. 1A
A cross-sectional view along the preliminary wiring 3 at point a is shown in FIG. 1B. A sectional view along the preliminary wiring 3 at the intersection 4b is also similar to FIG. 1B. The cross-sectional structure of the matrix type display device of this example will be explained with reference to FIG. 1B. Ta205, A I 203, Si3N on the entire surface of the glass substrate 5
The base coat film 6 consisting of 4 etc.
Formed to the thickness of a person. The base coat film 6 does not necessarily need to be provided. Picture element electrode 1 on base coat film 6
2. A preliminary wiring 3 is formed at the outer periphery (FIG. 1A) of the region where TFT II and the like are formed. Preliminary wiring 3 is
Generally, Ta, At, TI, N1, Mo, W
% Cr or a multilayer metal. In this embodiment, the preliminary wiring 3 is made of Ta and has a thickness of 30 mm.
It is formed by 00 people.

On the preliminary wiring 3, Ta205.5iNx (for example, 5l
A preliminary wiring insulating film 24 made of sNa) or the like is formed. When the preliminary wiring insulating film 24 is made of Ta205, it can be formed by anodizing the upper surface of the preliminary wiring 3. Further, on the base coat film 6, a gate bus wiring 2 (not shown in FIG. 1B) is also formed of the same metal as the preliminary wiring 3. Therefore, the preliminary wiring 3 and the gate bus wiring 2 intersect with each other with the preliminary wiring insulating film 24 interposed therebetween. In this embodiment, the gate bus line 2 is also formed of Ta to a thickness of 3000 nm so that the melting point of the preliminary line 3 is equal to that of the gate bus line 2.

A base insulating film 7, which also functions as a gate insulating film, is formed of SiNx (for example, 5I3N4) over the entire surface of the substrate 5, covering the preliminary wiring insulating film 24 and the gate bus wiring 2. The thickness of the base insulating film 7 is 1500~
A range of 6,000 people is suitable, but in this example, 200 people
The number was set in the range of 0 to 3,500 people. A source bus wiring 1 is formed on the base insulating film 7. Therefore, the preliminary wiring 3 and the source bus wiring 1 intersect with each other with the preliminary wiring insulating film 24 and the base insulating film 7 interposed therebetween. In this embodiment, the same Ta as the preliminary wiring 3 is used for the source bus wiring 1 in order to make the melting points of the preliminary wiring 3 and the source bus wiring 1 equal.

S I
N! A protective film 8 made of (for example, 5i3N4) is formed. The appropriate thickness of the protective film 8 is 2000 to 10
000 people, but in this embodiment, it is set to 5000 people. The protective film 8 and the above-mentioned base insulating film 7 are made of SiOx, Ta205, Al2O3, TiO2, Y, in addition to SiN.
It may also be formed from an oxide such as 2O3 or a nitride.

Moreover, without forming the protective film 8 on the entire surface of the substrate, the TFTI
I. It is also possible to form a window-opening shape in which only portions that are not directly involved in display, such as the source bus wiring 1, gate bus wiring 2, and spare wiring 3, are covered, and the central portion of the picture element electrode 12 is removed. An alignment film 9 is formed on the protective film 8 to regulate the alignment of liquid crystal molecules in the liquid crystal layer 21 which is a display medium.

The alignment film 9 is made of 5i02, polyimide resin, or the like.

On the glass substrate 20 facing the glass substrate 5, there are a counter electrode, a color filter (none of which is shown in FIG. 1B),
and an alignment film 17 are formed.

A black matrix (not shown) is provided around the color filter as necessary. A twisted nematic liquid crystal layer 21 is sealed between the glass substrates 5 and 20 as a display medium.

In the matrix type display device of this embodiment, defects caused by disconnections in the source bus wiring 1 or the gate bus wiring 2 can be corrected. By fully driving this display device,
When the source bus wiring 1 or the get bus wiring 2 is disconnected, a line defect starting from the disconnection is observed on the display screen. Which of the source bus wiring 1 and gate bus wiring 2 is broken can be determined by the direction of the line defect that has occurred. In the following, as shown in FIG. 1A, a case where a disconnection portion 4 occurs in the source bus wiring 1x will be described. Note that even if the gate bus wiring 2 is disconnected, it can be corrected in the same manner as described below.

When the disconnected source bus wiring 1x is identified, laser light, infrared rays, electron beams, or other energy is applied to the intersections 4a and 4b that intersect with the spare wiring 3 at both ends of the defective source bus wiring IX. irradiated. In this example, Y
AG laser light was used. The laser beam is indicated by arrow 2 in Figure 1B.
Irradiation can be performed from the substrate 5 side as shown by 3 or from the substrate 20 side as shown by arrow 25. The defective source bus wiring IX and the preliminary wiring 3 are melted by the laser beam irradiation, and the preliminary wiring insulating film 2 between these wirings IX and 3 is melted.
4 and the base insulating film 7 are destroyed, and the defective source bus line lx and the spare line 3 are electrically connected as shown in the shaded area 22. Note that when connecting the gate bus wiring 2 and the preliminary wiring 3, only the preliminary wiring insulating film 24 undergoes dielectric breakdown.

By connecting at the 21T point in this manner, the portions on both sides of the disconnection portion 4 of the defective source bus wiring 1x are electrically connected via the preliminary wiring 3.

In this embodiment, the preliminary wiring 3, the source bus wiring 1, and the gate bus wiring 2 are all made of Ta, so the preliminary wiring has the same melting point as that of the source bus wiring 1 and the gate bus wiring 2. There is. Therefore, at the intersections 4a and 4b where the connection was made by laser beam irradiation, the electrical connection between the defective source bus wiring IX and the spare wiring 3 is ensured, and the electrical connection at these intersections 4a and 4b is ensured. resistance is small. Therefore, the driver IC will not have insufficient capacity. Further, the defective source bus wiring IX and the spare wiring 3 will not come out of electrical contact due to later electrical, thermal, or mechanical shocks, changes, or the like.

Further, even if the connection is performed by laser beam irradiation as described above, since the protective film 8 is formed in this embodiment, the metal melted by the laser beam irradiation will not mix into the liquid crystal layer 21. Furthermore, since the protective film 8 is made of a transparent insulator, it allows laser light to pass therethrough.

Therefore, the protective film 8 is not destroyed by the laser beam. The liquid crystal layer 21 near the portion irradiated with the laser beam becomes cloudy, but this cloudiness disappears eventually, and the liquid crystal layer 21 is restored to its original state.

FIG. 2 shows a schematic diagram of another embodiment of the matrix substrate and matrix type display device of the present invention. In Figure 2, T P T, picture element electrodes, etc. are omitted for simplicity, and the gate bus wiring 2
, only the source bus wiring 1 and the spare wiring 3 are shown. In this embodiment, the preliminary wiring 3 includes four preliminary wirings 3a and 3b.
, 3c, and 3d. The preliminary wirings 3a and 3c and 3b and 3d do not intersect with the gate bus wiring 2 and the source bus wiring 1, respectively, and are connected by wiring such as conductive wires or jumper wires having small load capacitance and small electric resistance outside the substrate. For example, it is guided on a circuit board. On the circuit board, the wiring connected to the preliminary wiring 3a is arranged so as to be connectable to the wiring connected to the opposing preliminary wiring 3c.

Similarly, the wiring connected to the preliminary wiring 3b is arranged so as to be connectable to the wiring connected to the opposing preliminary wiring 3d.

Further, in this embodiment, the gate bus wiring 2 includes two sets of gate bus wirings 2a and 2b, and the gate bus wirings 2a and 2b are connected to different driver ICs, respectively. Similarly, the source bus wiring 1 consists of two sets of source bus wirings 1a and 1b, and the source bus wirings 1a and 1b are connected to different driver ICs.

In this embodiment, the preliminary wirings 3a and 3c are connected to the gate bus wiring 2.
By forming them simultaneously, the number of masks used for manufacturing the display device can be reduced. Similarly, by forming the preliminary wirings 3b and 3d at the same time as the source bus wiring l, the number of masks used in manufacturing the display device can be reduced.

A method of correcting a disconnection in the source bus wiring 1 of the display device of this embodiment will be described below. Note that even if the gate bus wiring 2 is disconnected, it can be corrected in the same manner as described below. Assuming that a disconnection 4 occurs in the source bus wiring 1x as shown in FIG. 2, the defective source bus wiring 1
and the preliminary wiring 3a are electrically connected by laser beam irradiation. Similarly, at the intersection 4b, the defective source bus wiring IX and the spare wiring 3c are electrically connected. Furthermore, on the circuit board mentioned above, the two wires connected to the preliminary wires 3a and 3c are electrically connected. By making electrical connections at three locations in this way, the source bus wiring 1b
Both ends of the disconnected portion 4 are electrically connected via wiring outside the board.

Also in this embodiment, the preliminary wiring 3, the source bus wiring 1, and the gate bus wiring 2 are all made of Ta, and the preliminary wiring has the same melting point as that of the source bus wiring 1 and the gate bus wiring 2. Therefore, at the intersections 4a and 4b where the connection was made by laser beam irradiation, the electrical connection between the defective source bus wiring IX and the spare wiring 3 is ensured, and the electrical connection at these intersections 4a and 4b is ensured. resistance is small. Therefore, the driver IC will not have insufficient capacity.

Further, the defective source bus wiring lx and the spare wiring 3 will not come out of electrical contact with each other due to later electrical, thermal, or mechanical shocks, changes, or the like. In each of the above embodiments, the case where the preliminary wiring 3, the gate bus wiring 2, and the source bus wiring 1 are all made of the same metal has been described, but the melting point of the metal used for the preliminary wiring 3 and the gate It is preferable that the difference between the melting points of the metals used for bus wiring 2 or source bus wiring 1 is within 1400°C, and if the melting point of the - metal is 100°C or more lower than the boiling point of the other metal, then either metals can also be used.

In this embodiment, only an active matrix type display device has been described, but the present invention can also be applied to other types of display devices. Furthermore, in the above embodiment, TPT
Although a matrix substrate and a matrix type display device using M as a switching element have been described, the present invention uses M as a switching element.
I M (Metal-insulator-meta)
l) It can be used in a wide range of matrix substrates and matrix type display devices using various switching elements such as diodes and varistors. Furthermore, as a display medium,
It can also be applied to various matrix substrates and matrix type display devices using thin film light emitting layers, dispersed EL light emitting layers, plasma light emitters, etc.

(Effects of the Invention) The matrix type display device of the present invention has a function of correcting disconnection of bus wiring, and the electric resistance of the corrected bus wiring is small and stable. Therefore, pixel defects can be reliably corrected, the yield of display devices can be improved, and the cost of display devices can be reduced.

4. Figure 1A is a circuit diagram of an embodiment of the matrix type display device of the present invention, Figure 1B is a sectional view taken along the preliminary wiring 3 at the intersection 4a in Figure 1A, FIG. 2 is a schematic diagram of another embodiment of the matrix type display device of the present invention.

1, la, lb-source bus wiring, 2, 2a.

2 b--Gate bus wiring, 3. 3a, 3b,
3c.

3d...Preliminary wiring, 4...Disconnection part, 4a, 4b...
- Intersection, 5.20... Glass substrate, 6... Base coat film, 7... Base insulating film, 8... Protective film, 9
, 17... alignment film, 10... counter electrode, 11...
TPT, 12... Picture element electrode, 16... Picture element capacitance, 2
1... Liquid crystal layer, 24... Preliminary wiring insulating film.

Figure 1A Figure 1B Dob

Claims (1)

[Claims] 1. Picture element electrodes arranged in a matrix on an insulating substrate, and scanning lines and signal lines arranged vertically and horizontally in rows in one direction between the picture element electrodes. and a matrix substrate having an insulating film at each end of at least some of the lines in at least one of the columns of the scanning line and the signal line. 1. A matrix substrate comprising preliminary wires that intersect with each other, the preliminary wires having a melting point close to the melting point of the part of the wires. 2. A matrix display device comprising the matrix substrate according to claim 1.