JPH0774940B2 - Display defect correction method for display device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to a method for correcting a display defect of a display device having a matrix-shaped display segment.

(B) Prior art As a display device having a matrix-shaped display segment, a liquid crystal display as disclosed in the article “Flat Panel Display for Document and Image Display” of Nikkei Electronics January 2, 1984 issue. There are various types of display devices, such as those that use a display device and those that use an electroluminescence display device.Currently, the future potential of liquid crystal display devices is highly evaluated in terms of low power consumption and large capacity. ing.

A plan view of the main part of such a conventional liquid crystal display device is shown in FIG. 3 (a), and its XX disconnection drawing is shown in FIG. 3 (b). In these figures, (10) is the first glass substrate,
(11) are arranged in rows and columns on the first glass substrate (10) with an insulating film (12) made of silicon nitride interposed between them, and transparent electrodes (13) ... 11) (11) ... An amorphous silicon film in which a plurality of gaps are arranged in parallel in the vertical direction, and an insulating film (12)
It is provided above. (14) ... are drain lines made of a plurality of aluminum films arranged in parallel in the vertical direction in a state where they partially overlap each other on the left side of each amorphous silicon film (13) with an insulating film (12) interposed therebetween. . (15) (15) are transparent electrodes (11) that are partially overlapped with the insulating film (12) on the right side of each amorphous silicon film (13).
(11) is a source electrode made of an aluminum film arranged corresponding to, and the right side thereof is each transparent electrode (11) (11) ...
Is connected to the lower left corner of the. (16) ... Gold formed between the first glass substrate (10) and the insulating film (12) by a plurality of transparent electrodes (11) (11) ... Is a gate line formed of a two-layer film of chromium and chromium, and the source electrodes (15) ...
, And the gate electrodes (17) ... Underneath the amorphous silicon film (13) at the gap position between the drain line (14) and the drain line (14) are integrally formed. That is, in the drain line (14) ... D shown in the figure, the source electrode (15) ... S, the gate electrode (17) ... G, and these electrodes D, S, G. Amorphous silicon film (13) connected to each other ... A switching transistor composed of a thin film FET is formed depending on the location, and each transparent electrode (11) (1
1) are connected to the drain lines (14) via the corresponding switching transistors. Reference numeral (18) is an alignment film in which the transparent electrodes (11) (11) ... And the drain lines (14) ...

On the other hand, (20) is a second glass substrate, and a common electrode (21) and an alignment film (28) are sequentially formed on one surface of the lower surface thereof, that is, the surface facing the first glass substrate (10). There is.

(3) is a liquid crystal substance enclosed between both substrates (10) and (20), and a first glass substrate (a voltage is applied to each matrix segment by applying a voltage by turning on the switching transistor). The liquid crystal substance (5) in the transparent electrode (11) of 10) causes the electro-optical effect.

In the display device having such a configuration, when a short circuit accident occurs at the intersection of the gate line (16) ... And the drain line (14) ... at each thin film FET, the thin line FET is supplied to this drain line (16). The video signal to be applied is applied to this gate line (14) via the short-circuited portion. Therefore, all the horizontal thin film FETs connected to the gate line (14) at the short-circuited location are turned on, and the horizontal transparent electrodes (1
1)… It will cause a line-shaped display defect in the segment.

Therefore, conventionally, the gate line signal which is the same timing signal and the drain line signal which is the same video signal are supplied from both ends of each gate line (16) and the drain line (14). Cut the left and right gate lines (16) of the short-circuited part or the upper and lower drain lines (14) of this part with a laser beam,
By isolating the short-circuited portion, the display defect of only the segment of this portion remains, but the display defect of all the segments of this line is solved. However, disconnect the left and right of the short-circuited part of the gate line (16) ...
Even if the gate electrode (17) of the FET is isolated, the video signal flows from the drain line (14) to the gate electrode (17) because the drain line (14) and the gate electrode (17) are short-circuited. Then the gate of the FET is turned on. Therefore, the video signal from the drain line (14) to the source electrode (15) is fed to the original gate line (16).
Even if the F voltage was applied, the current flowed in, and when the actual TV display was performed, there was the inconvenience that it turned on regardless of screen changes. For example, in the case of TN type black-and-white TV display (polarizing plate crossed Nicols), short-circuit correction points are shown as black dots on a white background.
Also, in the case of TN type color TV display (Nicol parallel to the polarizing plate), the color of the color filter at the short-circuit correction point developed on a black background, making it difficult to see.

(C) Problems to be Solved by the Invention The present invention has been made in view of the above points, and provides a method for correcting a drain-gate short-circuit portion that can visually reduce dot-shaped display defects. Is.

(D) Means for Solving the Problems According to the display defect correcting method of the present invention, the gate line at the short-circuited portion between the drain line and the gate line of the display device is cut, and at the same time, the connecting portion between the switching transistor and the display segment electrode is cut. It is a thing.

(E) Operation According to the display defect correcting method of the present invention, the FET at the location where the gate line and the drain line are short-circuited is separated from the gate line, and the FET and the display segment electrode are separated, so that the display Not only the signal of the gate line but also the signal of the drain line is not applied to the segment electrodes, so that the point defects become inconspicuous. (F) Example FIG. 1 shows a liquid crystal display device using the display defect correcting method of the present invention. In the figure, the same parts as those of the conventional device of FIG. 3 (a) are designated by the same reference numerals as those of FIG. 3 (a). The display defect correction method of the present invention is applied to a FET in which a short circuit (F) between the drain line (14) and the gate line (16) has occurred.
Supply the gate line signal from both ends of the gate line,
The point that the gate line (16) is cut by a laser beam at two places (c) and (c) on the left and right is the same as the conventional method of FIG. 3 (a), and the difference from the conventional method is the source of the FET. The transparent electrode (11) is also cut by the laser beam at the joint (A) between the electrode (15) and the transparent electrode (11).
That is, as described above, by cutting the gate line (16) at the points (c) and (c), the gate line (16) is cut.
Is prevented from short-circuiting between the drain line (14) and the transparent electrode (11) at the position (A), thereby avoiding application of a signal to this transparent electrode (11) which is a display segment. To be done.

Further, in the embodiment of the present invention shown in FIG. 2, a bypass line (19) coexists with the gate line (16) at the intersection of the drain line (14) and the gate line (16). The present invention is applied to a liquid crystal display device. In this case, either the gate line (16) or the bypass line (19) is short-circuited (F) with the drain line (14), and one of the short-circuited line (16) or (19) is applied to both ends thereof. Even if the lines (c) and (c) are cut off, the electrical connection of the gate line (16) is maintained at the other line (19) or (16).

If the display defect correcting method of the present invention as described above is adopted, TN
Even in the case of black-and-white TV display, the display point of the corrected portion is in a state of not being turned on at all regardless of the video signal. The same applies to TN color TV displays.

(G) Effect of the Invention According to the display defect correcting method of the present invention, the signal of the drain line which has conventionally been caused only by cutting the gate line of the FET which caused the short-circuit accident was detected. It is possible to eliminate the wraparound to the display segment electrodes. Therefore. In the conventional correction method, the defect display point may be displayed unrelated to the original display, but in the correction method of the present invention, the image quality is deteriorated due to the point defect as if the display of the defect display point is eliminated. Can be visually reduced, and a large improvement in the displayed image can be expected compared with the conventional method.

[Brief description of drawings]

FIG. 1 is a plan view of an essential part of a liquid crystal display device adopting the method for correcting a display defect of the present invention, and FIG. 2 is a plan view of an essential part of a liquid crystal display device of another embodiment using the method of the present invention. 1A and 1B are a plan view and a cross-sectional view of a main part of a liquid crystal display device using a conventional method. (11) …… Transparent electrode, (13) …… Amorphous silicon film, (14) …… Drain line, (16) …… Source electrode, (16) …… Gate line, (17) …… Gate electrode,
(19) …… Bypass line.

Claims (1)

[Claims] 1. A plurality of gate lines arranged in parallel,
Switching consisting of an FET provided with a gate electrode connected to the gate line at each intersection of a plurality of drain lines arranged in parallel on the gate line with an interlayer insulating film interposed therebetween. A method of correcting a display defect of a display device, comprising a transistor, a display segment electrode being coupled to a source side of each transistor, and a liquid crystal being sandwiched between the display segment electrode and a common electrode. When the gate line and the drain line at a location where there is a short circuit at the intersection, the gate line where the switching transistor is continuous, outside the region where the gate electrode and the intersection are continuously included and the drain The switch is connected to the gate electrode while being cut at two points across the line. Display disadvantage modification method of a display apparatus characterized by cutting the coupling portion of the display segment electrode and the transistor.