JP3877070B2 - Laser repair method for liquid crystal display and structure for laser repair - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a laser repair method and a laser repair structure for a liquid crystal display, and more particularly to a laser repair method and a laser repair structure using a dummy metal pattern of a liquid crystal display device.
[0002]
[Prior art]
Indicators are often seen in daily life. In particular, in the case of a television or a computer, a display device must be provided to display an image on the screen of the display device and show it to the user.
[0003]
In general, a cathode ray tube display has a large volume and thus lacks convenience in use. In particular, the cathode ray tube display cannot be applied to a notebook computer. Therefore, for example, a binary array type flat display such as a thin film transistor liquid crystal display (TFT LCD) has been proposed.
[0004]
A liquid crystal display is a display that does not emit light.
[0005]
The liquid crystal is interposed between the crystal and the liquid, and its molecular arrangement changes when it receives external energy such as an electric field. As the alignment of the liquid crystal molecules changes, the polarization direction of the light rays passing through the liquid crystal changes. By incorporating a polarizing plate using such liquid crystal characteristics, a light gate can be formed, so that a display element is formed.
[0006]
On the other hand, the thin film transistor is controlled from the outside, and one thin film transistor corresponds to one pixel. By applying a predetermined control electric field from the thin film transistor to the liquid crystal, the brightness of the liquid crystal is controlled.
[0007]
However, during the manufacture of liquid crystal elements, particularly thin film transistors, unexpected fine particles may remain or deposit on the thin film transistors due to poor control of the clean room, manufacturing equipment, or manufacturing conditions. Due to the presence of such fine particles, an abnormal circuit short circuit or open may occur, and the pixels corresponding to the defective thin transistor always become bright dots or dark dots, that is, a product defect may occur.
[0008]
When a defect occurs as described above, when the amount of defective pixels is small , a laser repair process is performed to repair the defective pixels .
[0009]
FIG. 1 is a cross-sectional view showing a configuration of a conventional thin film transistor portion and a conventional laser repair method.
[0010]
In FIG. 1, the thin film transistor liquid crystal display includes a transparent substrate 100 ( generally a glass substrate). A plurality of thin film transistors 102 which are arranged in a dot matrix and constitute image pixels are formed on the transparent substrate 100. A unique bit address is assigned to each of the plurality of thin film transistors 102.
[0011]
A frame-shaped sealant 106 is applied to the edge of the transparent substrate 100. Note that a liquid crystal filling opening exists in the sealant 106 before the liquid crystal is filled.
[0012]
A color filter 104 is attached to the sealant 106.
[0013]
By filling the liquid crystal from the opening of the sealant 106, the liquid crystal layer 108 is formed in a space composed of the color filter 104, the transparent substrate 100, and the sealant 106.
[0014]
When the opening of the sealant 106 is sealed with a similar sealant after the liquid crystal is filled, a semi-finished product of the thin film transistor liquid crystal display is formed.
[0015]
Subsequently , the light / dark state is checked for each pixel. If a defect is found in the thin film transistor, a laser repair process is performed.
[0016]
Conventional laser repair step, is condensed to high-energy thin film transistor of the laser beam 112 defect is found that are generated from the laser device 110, Ri Setsu baked wiring of a thin film transistor, or by heating a thin film transistor itself by laser Done to remove .
[0017]
However, according to the conventional laser repair process, the thin film transistor is removed, so that the defective pixel of the liquid crystal element becomes a dark dot permanently. That is, a defective pixel cannot display a color (red, blue, or green) that should normally be displayed. For this reason, on the screen, a display point including the defective pixel clearly exhibits an abnormal color as compared with a normal display point around the display point. This abnormal color is easily perceived by the user. This creates a problem where the user has questions about the quality of the product.
[0018]
[Problems to be solved by the invention]
In order to solve the above problems, an object of the present invention is to provide a laser repair method and a laser repair structure for a liquid crystal display in which an abnormal color display problem caused by a laser repair process of a conventional liquid crystal display is avoided. There is to do.
[0019]
Specifically, a first object of the present invention is to provide a simple liquid crystal display laser repair method and laser repair structure capable of repairing one defect by laser welding only twice.
[0020]
In addition, the second object of the present invention is to provide a laser repair method and a laser repair structure for a liquid crystal display which uses the thin insulating layer at the repair point to reduce the laser repair energy and improve the yield in defect repair. Is to provide.
[0021]
[Means for Solving the Problems]
In order to achieve the above object, a method of repairing a laser of a liquid crystal display according to the present invention includes a transistor having a source electrode and a drain electrode, a plurality of pixels each having a pixel electrode, and a pixel disposed in each pixel . In a liquid crystal display panel having a light shielding metal or a dummy metal as an insulating layer flattening metal, a method for repairing a defective pixel, wherein a first electrical connection portion is formed on the dummy metal in each pixel. A second electrical connection portion is formed in the dummy metal in each pixel, and a third electrical insulation is formed on the source / drain electrodes of the transistor in each pixel by the insulating layer from the first electrical connection portion. A source / drain of a transistor in a pixel adjacent to a pixel having a transistor which forms a connection portion and has the third electrical connection portion formed A fourth electrical connection layer that is insulated from the second electrical connection portion by an insulating layer is formed on the pole, and the first electrical connection portion and the third electrical connection portion in the defective pixel are formed by laser repair. And the second electrical connection portion in the defective pixel and the fourth electrical connection portion in the pixel adjacent to the defective pixel are electrically connected, and the transistor in the defective pixel is connected to the adjacent pixel. It is characterized by being connected to a transistor in a matching pixel.
[0022]
In order to achieve the above object, the laser repair structure of the liquid crystal display of the present invention includes a transistor having a source electrode and a drain electrode, a plurality of pixels each having a pixel electrode, and a pixel disposed in each pixel. In a liquid crystal display panel having a light-shielding metal or a dummy metal as an insulating layer flattening metal, the first electrical connection formed in the dummy metal in each pixel is a structure for repairing a defective pixel , A second electrical connection portion formed on the dummy metal in each pixel, and a source / drain electrode in a transistor in each pixel, and insulated from the first electrical connection portion by an insulating layer Transistors in a pixel adjacent to a pixel having a third electrical connection portion and a transistor forming the third electrical connection portion. A fourth electrical connection layer formed on the drain / drain electrode and insulated from the second electrical connection by an insulating layer, and the first electrical connection in the defective pixel and the Electrically connecting a third electrical connection portion, electrically connecting a second electrical connection portion in the defective pixel and the fourth electrical connection portion in a pixel adjacent to the defective pixel, and A transistor in a pixel can be connected to a transistor in an adjacent pixel.
[0023]
The dummy metal may be a dummy metal for shielding light leakage between adjacent pixels of the transmissive LCD substrate.
[0024]
The dummy metal may be a dummy metal for planarizing the insulating layer of the reflective LCD substrate.
[0025]
In addition, the fourth electrical connection portion straddles a scanning line between adjacent pixels.
[0026]
Further, the width of the fourth electrical connection portion across the scanning line is smaller than the width of other portions.
DETAILED DESCRIPTION OF THE INVENTION
The configuration and operation of an embodiment of the present invention that accomplishes the above-described object and eliminates the drawbacks of the prior art will be described in detail with reference to the accompanying drawings.
[0028]
2A is a plan view showing a laser repair method for a liquid crystal display (LCD) according to the first embodiment of the present invention, and FIG. 2B is an enlarged view of a part of FIG. 2A.
[0029]
A transmissive LCD substrate 10 has a plurality of scanning lines 12 extending in the horizontal direction, a plurality of data lines 14 extending in the vertical direction, and a plurality of pixel regions 16 arranged in a dot matrix. Here, each pixel area 16 is an area where two scanning lines 12 and two data lines 14 intersect.
[0030]
Each surface of the plurality of pixel regions 16 is covered with one pixel electrode 18. One thin film transistor is provided inside each of the plurality of pixel regions 16.
[0031]
A pattern of the floating dummy metal 20 (first metal layer) is provided between adjacent pixel regions and below the data line 14 (second metal layer). The pattern of the floating dummy metal 20 is formed at the same time as the scanning line 12 (first metal layer) and shields light leakage between adjacent pixel regions 16.
[0032]
In the first embodiment, two protruding electrical connection portions 20a and 20b are provided on the floating dummy metal 20 pattern. In addition, repair electrical connection portions 241a, 241b, 242a, and 242b are also provided on the source / drain electrodes 241 and 242 (second metal layer) of the thin film transistor, respectively.
[0033]
For example, if there is a defect 22 in order to repair the defect 22, performs laser welding at the points A and B, originally, not electrically connected (is isolated by not shown insulating layer) first The metal layer and the second metal layer are electrically connected.
[0034]
For this reason, the image signal is transmitted to the repair electrical connection portion 20b (point B) of the dummy metal 20 via the repair electrical connection portion 242b of the source / drain electrode 242 (second metal layer) of the thin film transistor, and the dummy metal 20 is transmitted to the repairing electrical connection part 241a (point A) of the source / drain electrode 241 of the thin film transistor through the repairing electrical connection part 20a. For this reason, the upper pixel electrode 18 (the pixel electrode corresponding to the source / drain electrode 241 of the thin film transistor) can be synchronously controlled via the source / drain electrode 242 of the lower thin film transistor.
[0035]
FIG. 3A is a plan view showing a laser repair method for a liquid crystal display (LCD) according to a second embodiment of the present invention, and FIG. 3B is an enlarged view of a part of FIG. 3A.
[0036]
A reflective LCD substrate 60 has a plurality of scanning lines 62 extending in the horizontal direction, a plurality of data lines 64 extending in the vertical and horizontal directions, and a plurality of pixel regions 66 arranged in a dot matrix. Here, each pixel area 66 is an area where two scanning lines 62 and two data lines 64 intersect.
[0037]
Each surface of the plurality of pixel regions 66 is covered with one pixel electrode 68. One thin film transistor is provided in each of the plurality of pixel regions 66.
[0038]
Further, in order to obtain a good flattening effect when the insulating layer (not shown) is flattened, a pattern of a plurality of floating dummy metals 70 (first metal layer) is provided at the center of each pixel region 66. . The pattern of the floating dummy metal 70 is formed simultaneously with the scanning line 62 (first metal layer).
[0039]
In the second embodiment, two protruding electrical connection portions 70a and 70b are provided in the floating dummy metal 70 pattern. In addition, repair electrical connection portions 741a, 741b, 742a, and 742b are provided so as to protrude from the source / drain electrodes 741 and 742 (second metal layer) of the thin film transistor.
[0040]
For example, if there is a defect 72, laser repair is performed at points A and B to repair the defect 72, and the first metal which is not originally electrically connected (isolated by an insulating layer not shown) The layer and the second metal layer are electrically connected.
[0041]
Therefore, the image signal is transmitted to the repairing electrical connection part 70b (point B) of the dummy metal 70 via the repairing electrical connection part 742b of the source / drain electrode 742 of the thin film transistor, and the electrical connection for repairing the dummy metal 70 is performed. It is transmitted to the repairing electrical connection portion 741a (point A) of the source / drain electrode 741 of the thin film transistor through the portion 70a. For this reason, the upper pixel electrode 68 (pixel electrode corresponding to the source / drain electrode 741 of the thin film transistor) can be synchronously controlled via the source / drain electrode 742 of the lower thin film transistor.
[0042]
As described above, laser welding need only be performed twice to repair a single defect. Therefore, the repair process is significantly simplified. Moreover, when using a method in which laser welding is used to electrically connect the first metal layer and the second metal layer separated by an insulating layer (thickness: 0.6 μm), the repair yield reaches 90%. This is because the thinner the insulating layer, the higher the yield. Further, the thinner the insulating layer, the lower the energy for laser welding.
[0043]
Since the electrical connection for repair of the source / drain electrode (second metal layer) of the thin film transistor straddles the scanning line , stray capacitance increases, signal delay becomes longer, and LCD display quality may deteriorate. However, if the stray capacitance is reduced by reducing the width of the electrical connection for repairing the source / drain electrodes of the thin film transistor that straddles the scanning line , the signal delay becomes longer and the display quality of the LCD deteriorates. Is done.
[0044]
In general, a conductive metal material such as aluminum or copper can be used as the first metal layer and the second metal layer, but a conductive non-metal material may also be used. For example, a conductive material such as polycrystalline silicon used as a gate material of a transistor or indium tin oxide (ITO) used as a material of a conductive layer can be used . When using polycrystalline silicon, it is preferable to further improve the conductivity by doping.
[0045]
Although the present invention has been presented as in the foregoing embodiments, this is not intended to limit the present invention, and those skilled in the art can make variations and modifications within the spirit and scope of the present invention. Therefore, the scope of rights of the present invention is equivalent to the scope of claims.
[0046]
【The invention's effect】
According to the present invention, laser welding need only be performed twice to repair a single defect. Therefore, the repair process is very simple. Moreover, the repair yield is high, reaching 90%, and the energy for laser welding is also reduced.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a conventional laser repair method for a liquid crystal display.
FIG. 2A is a plan view showing a laser repair method for a liquid crystal display according to Embodiment 1 of the present invention.
FIG. 2B is an enlarged view of a portion of FIG. 2A.
FIG. 3A is a plan view showing a laser repair method for a liquid crystal display according to Embodiment 2 of the present invention.
FIG. 3B is an enlarged view of a portion of FIG. 3A.
[Explanation of symbols]
10, 60 Substrate 12, 62 Scanning line 14, 64 Data line 16, 66 Pixel area 18, 68 Pixel electrode 20, 70 Dummy metal 22, 72 Defect 241, 242, 741, 742 Source / drain electrode 20a, 20b, 70a , 70b Electrical connection part for repair of dummy metal 241a, 241b, 242a, 242b, 741a, 741b, 742a, 742b Electrical connection part for repair of source / drain electrode 100 Transparent substrate 102 Thin film transistor

Claims (9)

A liquid crystal display panel having transistors each having a source electrode and a drain electrode , each having a plurality of pixels each having a pixel electrode, and a dummy metal serving as a light shielding metal or an insulating layer flattening metal disposed in each pixel In the method of repairing defective pixels,
Forming a first electrical connection on the dummy metal in each pixel;
Forming a second electrical connection on the dummy metal in each pixel;
Forming a third electrical connection portion insulated from the first electrical connection portion by an insulating layer on a source / drain electrode of a transistor in each pixel;
A fourth electrical connection layer that is insulated from the second electrical connection portion by an insulating layer is formed on a source / drain electrode of a transistor in a pixel adjacent to the pixel having the transistor in which the third electrical connection portion is formed. And
The first electrical connection portion and the third electrical connection portion in the defective pixel are electrically connected by laser repair, and the second electrical connection portion in the defective pixel and the pixel adjacent to the defective pixel are connected. A method of repairing a laser of a liquid crystal display, comprising: electrically connecting the fourth electrical connection portion to connect a transistor in the defective pixel to a transistor in the adjacent pixel.   The laser repair method according to claim 1, wherein the dummy metal is a dummy metal for shielding light leakage between adjacent pixels of the transmissive LCD substrate.   The laser repair method according to claim 1, wherein the dummy metal is a dummy metal for planarizing an insulating layer of a reflective LCD substrate.   2. The laser repair method according to claim 1, wherein the fourth electrical connection portion extends over a scanning line between adjacent pixels. 3.   5. The laser repair method according to claim 4, wherein a width of the fourth electrical connection portion across the scanning line is smaller than a width of other portions. A liquid crystal display panel having transistors each having a source electrode and a drain electrode , each having a plurality of pixels each having a pixel electrode, and a dummy metal serving as a light shielding metal or an insulating layer flattening metal disposed in each pixel In the structure for repairing defective pixels,
A first electrical connection formed on the dummy metal in each pixel;
A second electrical connection formed on the dummy metal in each pixel;
A third electrical connection formed on a source / drain electrode of the transistor in each pixel and insulated from the first electrical connection by an insulating layer;
A fourth electric connection layer formed on a source / drain electrode of a transistor in a pixel adjacent to the pixel having the transistor forming the third electric connection and insulated from the second electric connection by an insulating layer; And
The first electrical connection portion in the defective pixel and the third electrical connection portion are electrically connected by laser repair, and the second electrical connection portion in the defective pixel and the pixel in the pixel adjacent to the defective pixel are connected. A laser repair structure for a liquid crystal display, characterized in that a fourth electrical connection portion can be electrically connected to connect a transistor in the defective pixel to a transistor in an adjacent pixel.   The laser repair structure according to claim 6, wherein the dummy metal is a dummy metal for shielding light leakage between adjacent pixels of the transmissive LCD substrate.   7. The laser repair structure according to claim 6, wherein the dummy metal is a dummy metal for planarizing an insulating layer of a reflective LCD substrate. The fourth electrical connection spans a scanning line between adjacent pixels;
The laser repair structure according to claim 6, wherein a width of the fourth electrical connection portion across the scanning line is smaller than a width of other portions.

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