JPS63225229A - Thin-film transistor array - Google Patents

Abstract

PURPOSE:To reduce the man-hours required for the correcting operation in cutting off a thin-film transistor by arranging in parallel the connection between a scanning line and the gate electrode of each thin-film transistor and the connection between each picture element and the drain electrode of each thin-film transistor or the connection between a signal conductor and the source electrode of each thin-film transistor to separately and independently cut off each transistor. CONSTITUTION:The connection 9 between the scanning line 1 and the gate electrode 8 of the thin-film transistor connected to the line 1 and the connection 10 between each picture element electrode 3 and the drain electrode 7 of the thin-film transistor connected to the electrode 3 or the connection between the signal conductor and the source electrode of the thin-film transistor connected to the signal conductor are arranged in parallel, and the respective connections can be cut on a straight line. As a result, the correcting operation in cutting off the thin-film transistor can be carried out by one positioning and one laser irradiation in a certain straight-line range.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a thin film transistor (TPT) array used in an active matrix liquid crystal display device.

2. Description of the Related Art In recent years, new display devices to replace conventional CRTs have been actively developed. Among them, liquid crystal display devices have high expectations in the market for automobiles, watches, and home appliances because they are capable of low-power operation using an I film.

Conventionally, liquid crystal display devices used a simple drive method and were often small, but the contrast was poor and the density was high.

Because it is difficult to increase the size, active matrix display devices, in which each picture element is driven independently, are becoming promising. Among them, the market for liquid crystal display devices driven by thin film transistors, such as high-density compact televisions of 1 to 5 inches in size, is expanding.

However, the reality is that even commercially available pocket-type LCD TVs based on the active matrix system contain several pixel defects.

Currently, research and development is progressing on promising products such as 10- to 20-inch active matrix display devices and projection televisions that use liquid crystal light valves to enlarge and project small images. As the area increases, the number of picture elements increases, and the number of defects increases accordingly, resulting in an extremely low yield. As a means of remediating this defect, the defective transistor is cut using a laser or the like to eliminate line defects caused by cross shorts.
As described in Japanese Unexamined Patent Application Publication No. 121034/1986, there is a technique for turning a pixel defect that is always on into a non-lighting state.
By providing two or more thin film transistors for each pixel and cutting off the defective transistor side to eliminate the defect, or by applying adjacent pixel signals using sub-transistors, it is possible to create a display image that appears to have no problems. Techniques for obtaining this are known.

An example of the conventional thin film transistor array mentioned above will be described below with reference to the drawings.

Figure 3 (al is an equivalent circuit of a thin film transistor array, Figure 3 (bl is an equivalent circuit of an array composed of two thin film transistors per pixel, Figure 4 is a plan view of a conventional thin film transistor array, Figure 5 shows a cross-sectional view.In Figures 4 and 5, 8 is a gate electrode connected to the scanning line 1.

6 is a source electrode connected to the signal, %II8 and the semiconductor film 4a. A drain electrode 7 is connected to the picture element electrode 3 on the opposite side of the semiconductor film 4a and the connection portion 9.

The defect modes of the thin film transistor array configured as described above will be described below.

If a pinhole occurs in the insulating film 4b, a short circuit may occur between the gate electrode and the source electrode or between the gate electrode and the drain electrode, or a film may remain due to mask defects or poor etching, resulting in a short circuit between the source electrode and the drain electrode, resulting in damage to the thin film transistor. It becomes a defect.

Problems to be Solved by the Invention However, with the above configuration, as the area of thin film transistors increases or picture elements become smaller, more precise position control technology is required when cutting defective transistors, and Since cutting is performed at two locations per unit, after cutting one location, move the array or laser irradiation port (A-A in Figure 4) and align it with the second cutting location (B-B in Figure 4). Therefore, there was a problem that it took a lot of time.

In view of the above-mentioned problems, the present invention provides a thin film transistor array in which defective thin film transistors can be separated and corrected in one cutting unit (one position, one cut).

Means for Solving the Problems In order to solve the above problems, the thin film transistor array of the present invention has a connecting part between the scanning line and the gate electrode of the thin film transistor connected thereto, and a connection part between each pixel electrode and the gate electrode of the thin film transistor connected thereto. A device having a configuration in which the connecting portion with the drain electrode of a thin film transistor or the connecting portion between a signal line and the source electrode of the thin film transistor connected thereto is arranged in parallel, and each connecting portion can be cut in a straight line. It is.

Operation The present invention allows the gate electrode and the drain electrode or the gate electrode and the source electrode to be cut in a straight line with the above-described configuration, so that defects can be repaired in units of one cut.

EXAMPLE Hereinafter, a thin film transistor array according to an example of the present invention will be described with reference to the drawings.

FIG. 1 shows an equivalent circuit of a thin film transistor array according to an embodiment of the present invention, and FIG. 2 shows a planar configuration diagram. In FIG. 2, 9 is a connection between the scanning line 1 and the gate electrode 8, 10 is a connection between the picture element electrode 3 and the drain electrode 7, and the connection 9 and the connection 10 are arranged in parallel.

Defect modes and correction methods for the thin film transistor array configured as described above will be explained.

If a pinhole occurs in the insulating film 4b of the thin film transistor and a short circuit occurs between the gate electrode and the source electrode, the scanning line and the signal line are shorted through the thin film transistor, and the transistor on that line does not operate normally, resulting in a line defect. . Similarly, if a short circuit occurs between the gate electrode and the drain electrode, the lamp will be in a constantly lit state. To correct this defect, the connecting portion 9°10 is cut in a straight line with a YAG laser (A-A in Figure 2), and the defective transistor is separated from the scanning line 1 and signal line 2, thereby eliminating the defect or eliminating the defect. It can be reduced.

As described above, according to this embodiment, the connection between the scanning line and the gate electrode of the thin film transistor connected thereto is parallel to the connection between the pixel electrode and the drain of the thin film transistor connected thereto. By arranging the thin film transistor in a straight line, the modification work of separating the thin film transistor can be performed by one positioning and one laser irradiation in a certain linear range.

In this embodiment, the thin film transistor is cut at the gate electrode connection part 9 and the drain electrode connection part 10, but instead of the drain electrode 10, a branch wiring is provided at the source electrode, and the branch wiring is placed in parallel with the gate electrode and cut. You may.

In addition, in the case of a one-pixel two-transistor configuration as shown in Figure 3 (bl), it is completely defect-free, including short-circuits between the eyebrows between the gate electrode and drain electrodes, and adjacent short-circuits between the source and drain electrodes. It becomes possible.

Further, in this embodiment, the thin film transistor is cut using a YAG laser, but other methods may be used.

Effects of the Invention As described above, the present invention provides a connection portion between a scanning line and the yl thin film transistor gate electrode connected thereto in a thin film transistor array, a connection portion between each picture element and the drain electrode of the thin film transistor connected thereto, or , the signal line and the source electrode of the thin film transistor connected to it are arranged in parallel! By doing so, the correction work to separate the thin film transistor can be performed by one positioning and one laser irradiation in a certain linear range, so that the number of man-hours required for the correction can be significantly reduced.

[Brief explanation of drawings]

FIG. 1 is an equivalent circuit diagram of a thin film transistor array according to an embodiment of the present invention, FIG. 2 is a plan configuration diagram of FIG. 1, and FIG.
(al is an equivalent circuit diagram of a thin film transistor according to the conventional concept, Figure 3 is an equivalent circuit diagram of an array composed of two thin film transistors for one pixel, and Figure 4 is an equivalent circuit diagram of an array composed of two thin film transistors for one picture element.
FIG. 5 is a cross-sectional view of a conventional thin film transistor play. 1...Scanning line, 2...Signal line, 3...
...Picture element electrode, 4a...Semiconductor film, 4b,
5... Insulating film, 6... Source electrode, 7
......Drain electrode, 8...Gate electrode, 9, 10...Connection portion, 11...Liquid crystal, 12...Counter electrode. Name of agent: Patent attorney Toshio Nakao and one other person Figure 1+-1tL% (x+xtノ2-1s'jlff+γ!ノ

Claims (1)

[Claims] In a thin film transistor array for an active matrix display device, the connection part between a scanning line and the gate electrode of each thin film transistor connected thereto, the connection part between each picture element and the drain electrode of each thin film transistor connected to it, or the signal The line and the connection part between the source electrode of each thin film transistor connected thereto are arranged in parallel, and each transistor is connected to the line by thermal, chemical, electrical or mechanical means. A thin film transistor array characterized by being configured so that each individual can be cut independently.