JPS61147285A - Display element and repair thereof - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a display element having a thin film transistor (hereinafter referred to as TFT) array, in which a short-circuit in the electrode claw portion of the TFT can be easily repaired, and a method for repairing the same. It is related to.

Originally, a liquid crystal display device using a TPT as a driving element was created by sandwiching the liquid crystal between a transparent pixel electrode connected to the TPT on a transparent substrate and an opposing transparent conductive film.
It has the feature that it is possible to create a display device with a transmission structure that allows light to pass through the two lower substrates with high pixel density. By the way, this type of conventional device basically has a TFT substrate (matrix substrate) in which electrodes having two functions of a gate electrode, a drain electrode, and a source electrode are arranged in a matrix on a single substrate. It has been constructed by sandwiching liquid crystal between two substrates, a counter electrode substrate serving as a common electrode. As an example of a display device using such a conventional TPT substrate, a schematic cross-sectional view of a TPT active matrix liquid crystal display device is shown in Fig. 5.
As shown in the figure.

Referring to FIG. 5, a TPT as a switching circuit is formed on the glass substrate 1.
The gate electrode 2 includes a gate electrode 2 made of a metal thin film such as L, Cr, or Gu, an interlayer insulating layer 3 made of, for example, a SiN:H layer, and a semiconductor pad 4. Semiconductor pad 4 forming TPT
For example, Si, Cds.

CdSe, CdTe, Te, etc. are used, and amorphous, polycrystalline, or fine quality Si is preferably used. Amorphous Si can contain H atoms or halogen atoms (particularly F atoms). Each of the H atom and the halogen atom may be contained alone or both may be contained. The interlayer insulating layer 3 and the semiconductor layer 4 are formed by many commonly known methods such as a glow discharge method and a CVD method. A glow discharge method can be used to form layers at low temperatures.

Afl and Cr are connected to the semiconductor pad 4, respectively.

A source electrode 5 and a drain electrode 6 made of a metal such as Cu are provided, and a pixel electrode 7 forming a pixel (display section) is provided connected to the drain electrode. Pixel electrode 7
For example, indium-tin oxide (ITO)
Transparent electrodes such as tin oxide, gold thin film, etc. can be used.

An alignment layer 8 for liquid crystal alignment made of an organic thin film such as polyimide, polyparaxylylene, polyvinyl alcohol, etc. is provided covering the TPT structure as described above, and is connected to the alignment layer 9 of the counter substrate 12 made of the same material. A twisted nematic (TN) liquid crystal layer 10 is sandwiched between them. The counter substrate 12 is a glass substrate similar to the substrate 1, and an alignment layer 9 marked with L is provided on the counter electrode l1l- facing the pixel electrode 7.
has. These substrates 1 and +2-1- electrodes and other elements can be formed by the usual 8M deposition method and photolithography method. Moreover, the substrates l and 12 are
Fix with an appropriate sealing member to maintain a gap of, for example, 5 to 10
The gap is maintained at .mu.m, and the liquid crystal 10 is sealed in this gap. A pair of polarizing plates 1 is further placed on the outer side of the substrates l and 12.
3 and 14 are arranged, for example, in a crossed nicol or parallel nicol relationship, and are used for image display using irradiation light 15.

FIG. 6 is an equivalent circuit diagram when such TPTs are arranged in a matrix. The wiring of the gate electrode is connected to the necessary scanning lines XI + x7 1 x3, . . .
The number of the source wirings is equal to n, and the source wiring includes, for example, a signal line V+ necessary to achieve a desired horizontal resolution.
, V2, y3 +...y-. The TFT 21 is provided at each intersection, and a liquid crystal pixel 22 is formed between an electrode serving as a pixel for each drain and a counter electrode. The terminals 23 are commonly connected by opposing electrodes.

To drive this display panel, for example, by scanning and applying a pixel signal to the gate line and a driving voltage to the source line (only while the signal is being input to the gate line), the intersection of these electrodes is drain at the selected location (
Conductivity occurs between the dot electrodes), an electric field is generated between the drain electrode and the counter electrode, and the arrangement of liquid crystal molecules in the liquid crystal layer changes, thereby producing a display.

FIG. 7 is a plan view showing the middle cell of the TFT side substrate of the display device having such a configuration.

In FIG. 7, 31 is a gate wiring section, and 32 is a gate.

There is a semiconductor pad 34 provided on this gate via an insulating layer (not shown), a source line and a source wiring 35 are in contact with one end of the pad, and a drain 36 is in contact with the other end of the semiconductor, and the insulating layer is connected to a drain 36. A transparent electrode 37 is provided as a display pixel via the provided contact hole 3Ba.

When a photoconductive semiconductor material is used, at least the gate 32 below the semiconductor pad 34 is preferably made of a light-shielding material, and the gate wiring portion 31 may also be made of metal. At the same time, it is effective to provide a light shielding layer 33 on the TFTh via an insulating layer.For example, this terminal also has a contact hole 33.
It can be connected to the gate line 31 via 3a. With this configuration, the pitch in the X direction is P! A large number of pixels are created by repeating the pitch py in the y direction as a pattern. The part of this panel that shows optical changes effective for display is the transparent electrode 3.
Only the drain section consists of 7. As is clear from the figure, the gate wiring section 31 and the source wiring 35 cannot directly operate the liquid crystal and be used for display. That is, in the area of PxXPy corresponding to one pixel, the space that does not exhibit a display effect is due to the gap between the gate line and its wiring, the gap between the source line and its wiring, and the TFT itself and its light shielding member.

[Problems to be Solved by the Invention] When displaying a large screen panel using such a TPT substrate, the gate wiring section 31 and the source wiring 35 must not be electrically connected. However, in reality, a short circuit may occur at a portion 35b where the gate wiring portion 31 and the source wiring 35 overlap due to the influence of dust or the like during the process. When this part is short-circuited, the signal applied to the gate wiring section 31 and the signal applied to the source wiring 35 are mixed, and as a result, all the signals connected to the short-circuited gate wiring and source wiring via TPT are mixed. Mixed signals are applied to the transparent electrode, which appears as a crosshair-shaped defect when viewed as a panel display.

The present invention was made in view of these conventional problems.
An object of the present invention is to provide a TPT-driven display element and a method for repairing the same, which enables high-density pixel display without crosshair-like defects, without having to be relatively difficult to manufacture.

[Means for solving the problem] and [Operation] The display element of the first invention includes a plurality of electrodes. In a display element having a structure in which a layer of an electro-optic modulating material is sandwiched between a first substrate provided with a thin film transistor array and a second substrate provided with a counter electrode, an intersection between a gate line and a source line of the thin film transistor array is provided. The gate line section or source line section of the section is divided into at least two trees, which are combined into one tree before and after the intersection.

A second invention is a method for repairing the display element of the first invention, which comprises: checking for electrical shorts between the gate wiring part and the source wiring part in the electrode configuration described above; , which prevents the gate signal and source signal from mixing by cutting the short part before and after the intersection of the gate wiring part or the source wiring part, which is divided into two trees, using a laser or other means. It is.

[Example] The invention will be explained in detail based on drawings of pine wood.

FIG. 1 is a partial plan view showing an example in which the source wiring of a display element of the present invention is divided, FIG. 2 is a partial plan view showing an example in which the gate wiring is divided, and FIG. 3 is a partial plan view showing an example in which the gate wiring is divided. FIG. 3 is an enlarged partial plan view showing an example of an intersection between a wiring portion and a source wiring portion;

In FIG. 3, the source wiring 35 is divided into two parts before and after the part where it intersects with the gate wiring 31, and the crossing parts 85b1 and 65b
2 intersects with the gate wiring 31. Now source wiring 3
After forming No. 5, when inspecting the short-circuit portion between the source wiring portion and the gate wiring portion by applying 15 V with a short checker, the short-circuit portion No. 6 becomes a gray to black dot and can be confirmed with a microscope. Intersection 65b1 where this short point 68 is located
The short-circuit portion 68 could be separated from the source wire 35 by cutting the source wire portions before and after the source wire 35 using a carbon dioxide laser. FIG. 4 shows an enlarged partial plan view after repair.

In the above embodiment, an example in which the source wiring is divided into two parts has been described, but even if the gate wiring is divided into two parts as shown in FIG. 2, it is possible to repair the short circuit in the same way.

Further, in the present invention, in addition to the above-mentioned TN liquid crystal, chiral smectic C or H liquid crystal described in US Pat. No. 4,387,924 can be used as the liquid crystal.

[Effects of the Invention] According to the present invention, the source wiring or the gate wiring is divided into two parts before the intersection of the two wirings, and is later combined into one. Therefore, it is possible to repair short-circuited parts. Yield was significantly improved.

In other words, regarding the yield, if there are N crossing points and n short points, the yield Y (%) = (1-
-) becomes X 100. However, if we adopt the method of the present invention, which divides into two at the intersection, the number of parts is N 100,000, and n length 1.
Since there are 0 pieces, n' = (T10)・--LT-
=ON2 10 Therefore, by dividing the film into two at the intersection of the present invention and repairing it using means such as a laser, it was possible to reduce the number of cross-hair-like line defects to approximately 0%. ”-, if we increase the division ratio at the intersection of the source wiring part and the gate wiring part, for example, we can divide both the source wiring part and the gate wiring part into two parts, and create one source wiring and one It is clear that the yield is further improved if the gate wirings have four intersections. However, increasing the number of intersections by more than necessary is undesirable because it reduces the effective display area ratio of the display section.
It is necessary and sufficient to simply divide either the source wiring section or the gate wiring section into two at the intersection and connect them into one before and after the intersection. Also, regarding the restoration 111 steps,
Cutting with a laser was used in the example, but after forming the source wiring, a photosensitive resist was applied, the area to be cut was irradiated with a photosensitive beam, and after development, it was immersed in an etching solution that dissolves the source wiring material. A cutting method etc. can also be used.

[Brief explanation of the drawing]

FIG. 1 is a partial plan view showing an example in which the source wiring of a display element used in the present invention is divided, FIG. 2 is a partial plan view showing an example in which the gate wiring is divided, and FIG. 3 is a gate wiring section. FIG. 4 is an enlarged partial plan view showing an example of the intersection of the and source wiring, FIG. 4 is an enlarged partial plan view after repair of FIG. 3, and FIG. 5 is a TPT active using a TPT substrate with a conventional configuration. FIG. 6 is a schematic cross-sectional view of a matrix type liquid crystal display device, FIG. 6 is an equivalent circuit diagram when TPTs are arranged in a matrix, and FIG. 7 is a plan view showing an intermediate cell of the TFT side substrate. ■, 12 glass substrate, 2: gate electrode, 3: insulating layer,
4.34: Semiconductor batt, 5: Source electrode, 6.36:
Drain, 7.37.37a: Display pixel electrode, lO:
Liquid crystal, 11: Counter electrode, 31: Gate wiring, 32: Gate, 35: Source, 35a: Source wiring, Xl
, x7-...xn: gate line, yl, y7-
・・y,: Source line, 65b1.65b2: Intersection of source wiring and gate wiring, 68: Switch point at intersection

Claims (1)

[Claims] 1) A structure in which a layer of electro-optic modulating material is sandwiched between a first substrate provided with a thin film transistor array and a second substrate provided with a counter electrode, each of which has a plurality of electrodes. In the display element, the gate line portion or the source line portion at the intersection of the gate line and the source line of the thin film transistor array is divided into at least two lines, and the lines are combined into one line before and after the intersection. A display element characterized by: 2) A short-circuit between the gate line and the source line at the intersection of the gate line and the source line of the thin film transistor array, or at an intersection where the source line is divided into at least two lines. A method for repairing a display element, the method comprising cutting the gate line portion or the source line portion, which are divided before and after a location where the damage occurs.