JPH0614253B2 - Liquid crystal display - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method of relieving a defect in an active matrix panel, particularly in a driver-embedded active matrix panel.

[Prior art]

In an active matrix panel provided with a switching transistor array for writing signals to pixels by liquid crystal or the like, an attempt to build a driver circuit in the same substrate as the active matrix panel in the same manufacturing process as the switching transistor was made in 1981.
It started around this year, and the result is SID (Society on
Information Disply) etc. Since an active matrix panel usually has more than a hundred and a dozen gate lines and data lines, respectively, it is a driver integrated circuit (hereinafter abbreviated as a driver IC) that externally attaches a driver circuit for driving them. There are many cost disadvantages due to the manufacturing cost of the driver, the mounting cost of the driver IC, and the like. Therefore, it is very significant to enable the driver circuit to be built in the panel. However, a driver circuit including a shift register is more complicated to manufacture than a switching transistor that writes a signal to a pixel and has a high integration density of transistors, so that a defect is likely to occur and the yield of an active matrix panel may be reduced. There is. In the past, attempts were made to build a driver circuit in a panel, but as mentioned above, there has been almost no idea of means for relieving the reduction in yield of the panel due to the built-in driver circuit. Is.

〔Purpose〕

It is an object of the present invention to provide an effective means for relieving a defect generated in a driver circuit built in an active matrix panel and preventing a reduction in yield of the active matrix panel due to the built-in driver.

〔Overview〕

At least two series driver circuits are provided in the active matrix panel so as to drive at least one of the gate line group and the data line group of the active matrix panel from both sides, and the at least two series driver circuits are completely the same. Drive it so that
When there is a defective portion in at least one of the two series of driver circuits, only the defective portion is separated by a laser or the like.

〔Example〕

An outline of the structure of the driver-equipped active matrix panel is shown in FIG. In the figure, 101 and 1
Reference numeral 02 denotes a gate line driving driver, which has the same configuration and outputs the same signal to each of the output terminals to drive M gate lines 105, 106, 107 and the like. Similarly, the data line driving drivers 103 and 104
Are configured identically, and the output terminals output the same signal to output N data 108, 109, 1
10 etc. are being driven. Also, 111, 112, 11
Reference numerals 3, 114, 115 and the like are pixels including a switching element, and each pixel is configured as shown in FIG. 1 (b), for example. In FIG. 1B, 121 is a gate line and 12
2 is a data line, 123 is a switching transistor, 1
Reference numeral 24 is a pixel made of liquid crystal or the like.

The present invention will be described below by taking a gate line driving circuit as an example. FIG. 2 shows a method of repairing defects existing in the shift register cells in the driver circuit. In FIG. 2, two lines of gate line driver circuits 241 and 251 drive the gate lines 221, 222, 223, .... The gate line driver 241 is composed of shift register cells 201 to 206, and sequentially drives the gate lines 221 to 226 by the output signals of the shift register cells. The running order of the shift register is 201,
The order is 202, 203, ... The gate line driver 251 is also configured exactly the same as the gate line driver 241, and operates in the same manner. In FIG. 2, consider the case where the shift register cell 204 has a defect and the other shift register cells are quite normal. At this time, the gate lines 221 to 223 in the panel are driven by a normal signal, but the gate lines 224 and 22 after that are driven.
5, 226, ... Are driven by an abnormal signal and the panel is in a malfunction state. At this time, visual inspection,
After it is confirmed that there is a defect in the shift register cell 204 by means of a signal check in the shift register cell or the like, the shift register cell 204 is cut at 231 and 232 in the driver circuit 241. The cutting is performed by a laser trimming device or the like.

As a result of the above operation, the gate line 224 is normally driven by the output signal of the shift register cell 214, and 2
Gate lines 225, 226, ... After 25 are normally driven.

FIG. 3 shows a method of repairing defects existing in the pixel array of the active matrix panel. Driver circuit 341 and shift register cells 311, 312, 31 including shift register cells 301, 302, 303, ...
Suppose that the driver circuits 351 composed of 3, ... Are both operating normally and there is a defect in a pixel 331 driven by one gate line 322. At this time, the pixel 3
After confirming that there is a defect in 31, the gate line 32
2 and two places 332 at both ends of the pixel having the defect
And 333 are cut by a laser trimming device or the like. As a result, the active matrix panel operates normally except for one pixel of 331.

[Effect]

As is clear from FIG. 2, the active matrix panel, which is symmetrical to the defect repairing method of the present invention, has a structure in which at least two shift register cells are provided in parallel via a gate line (or a data line). ing. Therefore, as long as the shift register cells provided at the same position, for example, the cells 204 and 214 in FIG. 2 have no defects at the same time, the defect relief by the method of the present invention is possible. FIG. 4 is an example in which defects existing at a plurality of locations are repaired by the method of the present invention. In the figure, the shift register cells 403, 416, and 407 have defects, but the defects are relieved by cutting at the positions 432 and 433, 436 and 437, and 438 and 439, respectively. In addition, the defective pixel 431
Also, the defect relief is achieved by cutting at 434 and 435. As described above, almost 100% of defects according to the present invention can be repaired.

Also, according to the present invention, only defective shift register cells are disconnected, so that most of the gate lines (or data lines) are driven in parallel by at least two shift register cells. Therefore, the capacity for driving the capacitive load of the gate line (or the data line) can be afforded, and the panel can be driven with a signal waveform closer to the ideal.

As described above, by applying the present invention, the manufacturing yield of the active matrix panel with built-in driver can be improved, the manufacturing cost can be reduced, and at the same time, a high quality panel can be manufactured.

[Brief description of drawings]

1A and 1B are diagrams for an active matrix panel with a built-in driver. 2 and 3 are views showing an embodiment of the present invention. FIG. 4 is a diagram for explaining the effect of the present invention. Outline the statue

Claims (1)

[Claims] 1. A liquid crystal in which liquid crystal is enclosed in a pair of substrates, and one of the substrates has pixel electrodes arranged in a matrix and transistors connected to the pixel electrodes. In the display device, a pair of scanning line driving circuits composed of a plurality of shift register cells are symmetrically formed around the display region on the substrate across the display region, and one scanning line driving circuit scans one of the scanning line driving circuits. The scanning signal line from the line driving circuit is connected to the transistor in the display area, and is connected to the other scanning line driving circuit in the periphery of the display area, and the pair of scanning line driving circuits is connected through the scanning signal line. The liquid crystal display device is characterized in that the same signal is supplied from the circuit to the transistor, and defective cells of the shift register cells are cut off by laser trimming in cell units.