JPH06235926A - Active matrix liquid crystal display panel - Google Patents

Abstract

(57) [Summary] [Objective] In an active matrix liquid crystal display panel, the number of intersections between scanning lines and signal lines and a repair ring for repairing these defects is reduced to improve the yield of products. [Configuration] Floating pads are provided at the ends of the scanning lines and the signal lines. For example, when a disconnection portion 19 exists in the scanning line 1-2, the intersection 9 of the repair ring 14-1 and the line 1-2
Welds are made at points -1, 9-2 and at the floating pad at point 9-3, and the repair ring 14-1 is cut at points 11-1, 11-2. The signal voltage supplied to the line 1-2 is supplied to the left half of the line and also to the right half of the line 1-2 from the point 9-1 through the upper half of the repair ring 14-1. To be done. The lower half of the repair ring is used to repair other lines. The disconnection repair of the signal line is similarly performed.
Since only one repair ring is required, the number of intersections with the scan lines and the signal lines is reduced, and thus short circuits at the intersections are reduced, so that the product yield is improved.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION This invention relates to display panels for active matrix liquid crystal display (LCD) systems.

[0002]

2. Description of the Related Art In a liquid display device, the display area is much larger than that of an integrated circuit (IC) chip. Dust particles,
Incomplete yellow exposure or pinhole shorts and breaks during photolithography work are very likely to result in defective conductor lines. To avoid such defects, it is not only important to ensure cleanliness during manufacturing,
It would also be desirable to provide a repair design to repair this defect. A conventional basic repair design is shown in FIG. Restoration rings 14-1, 14-2, ... Are attached to surround the pixel region 12. The greater the number of repair rings, the greater the number of repairable defects such as wire breaks and shorts. In FIG. 10, four scanning lines 1-
1, 1-2, 1-3, 1-4 and four signal lines 2-
1, 2-2, 2-3, 2-4 are shown. Each pixel includes a thin film transistor 20 and a storage capacitor 22. All bottom electrodes of the storage capacitors are connected to a common reference potential.

The conventional repair method is as follows. That is, assuming that scan line 1-1 is broken at point 18, the right half of this scan line cannot receive the signal voltage, and half of the line becomes defective. Therefore, the repair ring is connected by laser welding to the divided line 1-1 at points 6-1 and 6-2 (welding points), respectively. At the intersection 10 of the repair ring with the scan line and the signal line, the cross-section layer goes from the bottom upwards to the first metal /
It is the gate dielectric / second metal. Ideally,
There should be no short circuit between the first metal (metal for the gate electrode) and the second metal (metal for the repair ring) before laser welding. After the laser welding, the upper half of the repair ring 14-1 repairs the defect line 1-1. The lower half of the repair ring 14-1 is cut off by laser cutting at points 8-1 and 8-2. Thus, the lower half of the repair ring can be used to repair defects in other lines.

The problem of a short circuit between the scan line and the signal line can also be repaired in a similar manner. First, the laser is used to cut the shorted portion 16 at points 8-3, 8-4. Next, laser welding is performed at points 6-3 and 6-4, and laser cutting is performed at points 8-5 and 8-6 on the right side of the welding point. In this way, the short circuit is removed and the signal can flow from point C through the left portion of the repair ring 14-2 to point 6-4, thus eliminating the discontinuity in signal line 2-2. Therefore, the lower half of the signal line can also receive the signal, and any disconnection or short circuit of the signal line or the scanning line is repaired.

[0005]

However, such repair methods require at least two weld points between the repair ring and the signal or scan line for repair. The large number of lines also increases the number of weld points and significantly increases the likelihood of shorts between the signal and scan lines, thus reducing production yield. In today's LCD manufacturing methods, the gate electrode and the electrode of the storage capacitor are treated with the same metal at the same time. These two electrodes are customarily designed with an interdigital finger geometry as shown in FIG. 11 to avoid short circuit defects. In FIG. 11, the scanning lines 1-1, 1-2, 1-3, 1-4, and the finger-shaped common electrodes of the capacitors 24-1, 24-2, 24-3, 24-4 are comb teeth. Are separated into a shape. Such a layout greatly increases the number of intersections between the scan ring, the signal line, and the common electrode of the capacitor and the repair ring, and thus makes the short-circuit defect more likely to occur.

As shown in FIG. 12, if the scan line and the common electrode of the capacitor are shortened so that the termination exists inside the repair ring, the number of intersections of the scan line and the repair ring is reduced by half. However, the number of intersections between the common electrode of the capacitor and the repair ring is reduced to only two. This is shown in FIG. 12 by the line from the pad 26 that intersects the repair rings 14-1, 14-2. However, if there is a disconnection of the scan line or a disconnection of the common electrode of the capacitor, these lines only intersect with the repair ring at only one point, so the number of intersections is insufficient for repair. Become. The above-described method shown in FIG. 11 increases the number of intersections between the repair ring and the scan lines, signal lines and common capacitor electrodes, but also increases the occurrence of short circuits between them. On the other hand, the method shown in FIG. 12 reduces the number of intersections, but cannot repair the disconnection. Therefore, these methods are
The manufacturing yield of the panel cannot be improved.

[0007]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a design in which a defect line in an active matrix LCD panel can be repaired by a repair ring. Another object of the present invention is to provide a design capable of repairing defective lines in an active matrix LCD panel having a small number of intersections between scan lines and signal lines and a repair ring. Yet another object of the present invention is to provide a high yield, low cost design for active matrix LCD panels. These objects are, in the present invention,
This is accomplished by providing a "floating pad" for each scan line and providing the capacitor common electrode near the end of the line. The floating pad has two overlapping electrodes separated by a dielectric, one of which is connected to the line and the other intersects the repair ring. If one of the lines is defective, laser welding is used to short circuit the floating pad and the intersection of the floating pad with the other electrode and the repair ring, and the other end of the defective line to the repair ring. Short circuit. Therefore, the defective portion is replaced by the repair ring. This structure can reduce the intersection of the line and the repair ring in half, which improves the manufacturing yield.

[0008]

Embodiments of the present invention will be described with reference to FIG.
In FIG. 1, scanning lines 1-1, 1-2, 1-3, 1-
4 and common electrodes 24-1, 24 for the end of each line
-2, 24-3, and 24-4, "floating pad" 3
0 is attached. This floating pad acts as an isolation switch. When one line requires repair, two intersections are required to contact the repair ring. But,
When the floating pad acts as an isolation switch, the number of scan line and repair ring intersections is halved, and the common electrode and repair ring have N intersections. Here, N is the number of repair rings. Reducing the number of intersections reduces the occurrence of short circuits. A "test pad" 28 serves to test whether the scan line or common electrode is open.
When a voltage is applied between the input pad of scan line 1-1 and the test pad 28, a break will be present if the current is zero. FIG. 2 shows how floating pads are attached to the ends of signal lines. FIG. 3 shows a crossing state of the floating pads 30. Repair rings 14-1 and 1
4-2 is made of the second metal 38, and the scanning line 34 is made of the first metal. A gate dielectric 36, such as silicon nitride (SiNx), is interposed between the first metal and the second metal. The floating pad 30 also consists of a first metal 34, a gate dielectric 36 and a second metal 38. The top second metal of the floating pad is connected to the bottom first metal below the repair rings 14-2, 14-2 via through holes in the gate dielectric.

The scan line repair procedure is shown in FIG. Assuming that the scan line 1-2 has a broken portion 19, laser welding is performed at points 9-1, 9-2, 9-3. Laser cutting is performed at points 11-1 and 11-2 to restore ring 14-1.
The lower half is cut so that it can be used to repair another defect. The signal voltage on the scan line is
From point 9-1 through the upper half of the restoration ring 14-1 to point 9-1
-2 and points 9-3. As a result, the right half of the scan line 1-2 can receive the signal voltage. Figure 5 shows how the signal lines can be repaired. Assuming that the signal line 2-2 has a broken portion 21, laser welding is performed at points 17-1, 17-2 and floating pad point 17-3 to form a weld point. Laser cutting is performed at points 19-1 and 19- on the repair ring 14-1.
2 takes place. The signal for line 2-2 is at point 17
Can be added to the cut from -1, 17-2 and 17-3. If there is a short circuit between the scan line and the signal line, or a short circuit between the common electrode and the signal line in the pixel area, this short circuit portion is cut first, and then the signal line is shown in FIG. It can be repaired by the method.

There are four methods of repairing the break in the common electrode, and FIG. 6 shows a method using four welding points. If the common electrode wire 24-2 has the disconnection portion 23, laser welding is performed 25-1, 25-2, 25-3, 25-, respectively.
4 to form weld points. Laser cutting is performed at points 27-1 and 27-2, respectively. Next, the broken line segment 23 is connected from the point 25-1 to the point 25-4 via the adjacent common electrode, and the repair is completed. FIG. 7 shows a method of repairing one broken (broken) common electrode wire using three welding points. If the common electrode wire 24-2 has the disconnection portion 23, laser welding is performed at points 29-1, 29-, respectively.
2, 29-3 to form weld points. Laser cutting is performed at points 31-1, 31-2 and the repair ring 14-
Cut the upper half of 1. The disconnection portion is connected to the common electrode potentials at points 29-1 and 29-2 to 29-3.

FIG. 8 illustrates a method using a common repair bar and two weld points. A common floating bar 39 is attached to the end of the floating pad. This bar consists of the second metal 38 of FIG. The broken portion, that is, the broken wire portion 23, has welding points 33
-1, 33-2 can be connected to the pad 26. Laser cutting is done at the common repair bar at point 35 to separate the lower half of the repair bar. FIG. 9 shows a common restoration bar method using two weld points. The ends of the common electrode lines are connected together in groups of 2, 3 or N lines by a common repair bar indicated by bar 40. If the disconnection portion 23 exists, laser welding is performed at points 37-1 and 37-2, respectively.
And a weld point is formed. Then, the disconnection portion 23
Are connected through these weld points to complete the repair.
If there are two damaged routes, 3 in one group
N in a book or a group of common restoration bars
The book can be used for restoration. Thus, repairing the common electrode line does not require the use of any repair ring. These repair rings can be retained for scanline repair.

[0012]

Since the present invention is configured as described above, the number of intersections between the scanning line and the signal line and the repair ring is reduced, and the increase in the occurrence of short circuits due to the reduction is reduced. Since the repair of the defective line can be surely executed although the number is small, the yield of the LCD panel is increased and the low cost design is possible.

[Brief description of drawings]

FIG. 1 is a diagram showing one design method of the present invention by attaching a floating pad to a scan line and a capacitor common electrode.

FIG. 2 is a diagram showing another design method of the present invention by attaching a floating pad to a signal line.

FIG. 3 is a sectional view for explaining a floating pad.

FIG. 4 is a diagram showing a method of repairing a disconnection in a scanning line with a floating pad.

FIG. 5 is a diagram showing a method of repairing disconnection in a signal line by a floating pad.

FIG. 6 is a diagram showing a method of repairing a break in a common electrode of a storage capacitor by using four welding points.

FIG. 7 illustrates a method of repairing a break in the common electrode of a storage capacitor that includes a floating pad using three weld points.

FIG. 8 illustrates a method of repairing a break in the common electrode of a storage capacitor using two weld points and a common repair bar.

FIG. 9 is a diagram showing a method of repairing disconnection in a common electrode of a storage capacitor by using two or more common repair bars.

FIG. 10 shows a conventional design of an active matrix LCD panel that repairs disconnections and shorts in column and row conductors.

FIG. 11 is a view showing a constraint of a conventional design for repairing defects in a scanning line, a capacitor common electrode and a signal line.

FIG. 12 illustrates another conventional finger shape design constraint for repairing defective lines.

[Explanation of symbols]

 12 Pixel Region 14 Repair Ring 19, 21, 23 Disconnection Part 22 Storage Capacitor 24 Common Electrode 30 Floating Pad 36 Gate Dielectric 39, 40 Floating Bar

Claims (26)

[Claims] 1. An active matrix liquid crystal display panel, comprising: at least two groups of parallel conductors provided in a display area; and at least one conduction restoration element arranged outside the active area of the display area. And said parallel conductor and said repair element are respectively arranged in a first conductive layer and a second conductive layer separated by a dielectric layer, and further connected to each end of said parallel conductor. A floating pad having a first electrode and a second electrode separated and overlapped by a dielectric layer, the first electrode being the first pad
Connected to the parallel conductor existing in the conductive layer of
A floating pad configured to intersect the repair element present in the second conductive layer, the floating pad, and an intersection between the second electrode of the floating pad and the repair element. And a means for repairing the defective line of the parallel line by short-circuiting the first conductive layer and the second conductive layer, the repair element connecting a connection to the other end of the defective line. An active matrix liquid crystal display panel characterized by having. 2. The active matrix liquid crystal display panel according to claim 1, wherein the repairing means is achieved by laser welding. 3. The active matrix liquid crystal display panel according to claim 1, wherein the connection is made at a second intersection between the repair element and the other end of the defect line. 4. The active matrix liquid crystal display panel according to claim 2, wherein the connection is made by laser welding. 5. The active matrix liquid crystal display panel according to claim 1, wherein the repair element is a ring. 6. The active matrix liquid crystal display panel according to claim 5, wherein an unused portion of the ring is cut. 7. The active matrix liquid crystal display panel according to claim 6, wherein the unused portion is cut by a laser. 8. The second electrode of the floating pad extends from the first conductive layer in a display area to the second conductive layer at an intersection with the repair element. The active matrix liquid crystal display panel according to claim 1. 9. The active matrix liquid crystal display panel according to claim 1, wherein the defective line has a disconnection portion. 10. The active matrix liquid crystal display panel according to claim 1, wherein the parallel conductors are common electrodes of alternating scan lines and pixel storage capacitors. 11. The active matrix liquid crystal display panel according to claim 10, wherein the parallel lines of the common electrode are short-circuited at one end. 12. The floating pad for the common electrode is located at an end opposite the shorted end, and the defective common electrode shorts the extension of the electrode of the floating pad by the repair element. And the repair element is adapted to be repaired by shorting a good common electrode extension.
Active matrix liquid crystal display panel described. 13. Shorting the extension of the good common electrode shorts the floating pad at the good common electrode and also shorts the extension of the floating pad by the restorative element at the intersection with the restorative element. 13. The active matrix liquid crystal display panel according to claim 12, wherein the active matrix liquid crystal display panel is configured to perform the above. 14. The active matrix liquid crystal display panel according to claim 12, wherein the short circuit of the repair element by the good element is configured to occur at the input line to the short element of the common electrode. 15. The floating pad for the common electrode is located at an end opposite the shorted end and is connected to a common repair bar located inside the repair ring,
Defective common electrode lines may be repaired by short-circuiting three points: the floating pad on the defective line, the floating pad electrode extension, and the floating pad electrode extension on the good common electrode line. The active matrix liquid crystal display panel according to claim 11, which is configured. 16. The active matrix liquid crystal display panel of claim 15, wherein one or more said repair bars are present. 17. The active matrix liquid crystal display panel according to claim 1, wherein a test pad is connected to each of the parallel conductors. 18. The active matrix liquid crystal display panel according to claim 1, wherein a plurality of parallel signal lines perpendicular to the scan lines are arranged in the second conductive layer. 19. A second set of floating pads is connected to the ends of the parallel signal lines, each of the pads being connected to the signal lines present in the second conductive layer. An electrode and a second electrode that is present in the first conductive layer and extends to intersect at least one repair ring, the first conductive layer and the second conductive layer Three points: the second floating pad, the intersection between the extension of the floating pad and the second repair element, and the second repair element at the end of the defective signal line. 19. The active matrix liquid crystal display panel according to claim 18, further comprising means for repairing a defective signal line by short-circuiting at the intersection. 20. Active according to claim 19, characterized in that the repairing means is achieved by laser welding.
Matrix liquid crystal display panel. 21. The active matrix liquid crystal display panel according to claim 19, wherein the defective signal line has a disconnection portion. 22. The active matrix liquid crystal display panel according to claim 17, wherein the repair element is a ring. 23. The active matrix liquid crystal display panel according to claim 22, wherein a part of the unused repair element is cut off. 24. The active matrix liquid crystal display panel according to claim 23, wherein a part of the unused repair element is cut by a laser. 25. The active matrix liquid crystal display panel according to claim 17, wherein the defective line has a short circuit portion with the first conductive layer. 26. The active matrix liquid crystal display panel according to claim 25, wherein the defective portion is repaired by cutting the short-circuited portion by laser cutting.