JPH08179356A - Liquid crystal display device - Google Patents

Abstract

PURPOSE: To make it possible to check the potential of the common electrode of a second substrate at the time of applying a prescribed potential on pads for the common electrodes of the wirings of a first substrate by providing a liquid crystal display device with potential routes from the pads on the first substrate toward the common electrode via wiring films. CONSTITUTION: This liquid crystal display device has plural potential transmission routes from the pads 2a of the TFT substrate to the common electrode 6 of the CF substrate 5 through the wiring films 3a and conductive microbars 4. The connection points of these two potential transmission routes and the common electrode 6 are not near to each other and are apart from each other. The application of the potential for the common electrode 6 from the one pad 12a of the pads 2a, 2a and the detection of the potential of the common electrode 6 through the other pad 2a are possible with such liquid crystal display device. For example, the easy detection of the potential is made possible by bringing a probe into contact with the other pad 2a. Then, the early discovery of potential abnormality at the time of occurrence of such abnormality is possible.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device, in particular, a first substrate having a wiring formed on the surface thereof and a second substrate having a common electrode formed on the surface thereof, with a predetermined distance between the surfaces. Facing each other, a sealed space is formed between the surfaces, liquid crystal is sealed in the sealed space, and a predetermined voltage is applied from the pad and the wiring film of the first substrate to the common electrode of the second substrate. The present invention relates to such a liquid crystal display device.

[0002]

2. Description of the Related Art As a liquid crystal display device, a common electrode forming surface of a CF substrate is opposed to a surface of a TFT substrate on which a thin film transistor is formed, and both substrates are adhered to each other so that a sealed space can be formed therebetween. Some have liquid crystal enclosed. And in such a liquid crystal display device, TF
A predetermined voltage, for example, 5.6 V, from the pad and wiring film on the T substrate to the common electrode on the CF substrate through the conductive micropearl.
Is applied. FIG. 2A is a perspective view showing an outline of such a liquid crystal display device. In the drawing, 1 is a TFT substrate, on the surface of which a pixel electrode driven by a thin film transistor, a wiring connected to the thin film transistor are formed, and further, there are lead-out pads 2, 2 of the internal circuit of the liquid crystal display device. ing. One of the pads 2a is a wiring film 3a and a conductive micropearl 4
The pad is connected to the common electrode (6) of the CF substrate (5) described below via.

A CF substrate 5 has a common electrode 6 on its surface. The surface of the CF substrate 5 on which the common electrode 6 is formed is made to face a portion of the surface of the TFT substrate 1 on which the wiring and the like are formed other than the pad formation region at a predetermined interval, and a sealed space is formed therebetween. As it is generated, it is adhered by an adhesive made of resin, and the liquid crystal is enclosed in the closed space. For the sake of convenience, illustration of the adhesive and liquid crystal is omitted. In order to operate the liquid crystal display device, it is necessary to apply a predetermined voltage (for example, 5.6 V) to the common electrode 6 from the outside, and the application is performed through the pad 2a. That is, a predetermined potential (for example, 5.6V) is applied to the common electrode 6 via the pad 2a, the wiring film 3a, and the conductive micropearl 4. FIG. 2B is a circuit diagram showing a path for applying a predetermined potential to the common electrode 6. R1 is the resistance of the thin wiring film 3a formed on the TFT substrate 1, and R2 is the wiring film 3a and the conductive micropearl 4
And the contact resistance between the micropearl 4 and the common electrode 6.

[0004]

However, in a liquid crystal display device, the potential applied to the pad 2a and the potential at the common electrode 6 of the CF substrate 5 may not be equal due to various causes. The potential of the common electrode 6 has a great influence on the blinking operation of the liquid crystal, and if the potential of the common electrode 6 is abnormal, a good blinking operation cannot be expected. For example, due to an abnormality of the common electrode 6, for example, an electric double layer is formed,
The image quality may deteriorate due to the electric double layer. The continuous use often expands the area where the electric double layer is generated, and as a result, the area where the image quality is deteriorated is expanded, and the image quality is not negligible.

If such a defect can be found during the manufacturing process of the liquid crystal display device, it is possible to eliminate the waste of discarding the defective liquid crystal display device at an early stage from the production line and continuing to assemble the defective one. Not only that, the pursuit of the cause can be started quickly, which is advantageous in quality control. However, conventionally, when a predetermined potential was applied to the pad 2a, it was not possible to confirm whether or not the same potential was applied to the common electrode 6. Therefore, it is not impossible that an abnormality of the common electrode 6 of the liquid crystal display device is discovered only after reaching a stage close to the finished product, resulting in waste of the entire lot.

The present invention has been made in order to solve such a problem, and the surface of the first substrate having the wiring formed thereon and the surface of the second substrate having the common electrode formed on the surface thereof are connected to each other. A sealed space is formed between the surfaces, facing each other at a predetermined interval, liquid crystal is sealed in the sealed space, and a predetermined voltage is applied to the common electrode from the pad and wiring film of the first substrate. In the liquid crystal display device according to the present invention, when a predetermined potential is applied to the common electrode pad of the wiring of the first substrate,
The purpose is to be able to confirm the potential of the common electrode of the substrate.

[0007]

The liquid crystal display device according to claim 1 is characterized in that there are a plurality of potential paths from the pads of the first substrate to the common electrodes via the wiring films.

[0008]

According to the liquid crystal display device of the first aspect, a predetermined potential is applied to the common electrode through one of the pads reaching the common electrode, and the potential of the common electrode is measured through another pad reaching the common electrode. can do. Therefore, the potential of the common electrode can be confirmed, and in turn, the potential abnormality can be detected early.

[0009]

The present invention will be described in detail below with reference to the illustrated embodiments. 1A and 1B show one embodiment of the liquid crystal display device of the present invention, and FIG. 1A is a schematic perspective view,
(B) is a circuit diagram of a potential path to the TFT substrate.
Note that the illustration of the adhesive and the liquid crystal is omitted as in FIG. This liquid crystal display device is different from the conventional liquid crystal display device shown in FIG.
From the pad 2a of the TFT substrate 1 to the common electrode 6 of the CF substrate 5
Although there is a large difference in that it has two potential transmission paths leading to, the other points are common, and since the common points have already been described, the description thereof will be omitted and only the different points will be described. To do. Further, common parts are denoted by common reference numerals throughout the drawings.

In the present liquid crystal display device, the pad 2a of the TFT substrate 1 is passed through the wiring film 3a and the conductive micropearl 4 to form a C film.
The F substrate 5 has a plurality of potential transmission paths to the common electrode 6, and the connection points of the two potential transmission paths with the common electrode 6 are not close to each other but are separated from each other.

In such a liquid crystal display device, the potential for the common electrode 6 can be applied from one of the pads 2a, 2a, and the potential of the common electrode 6 can be detected through the other pad 2a. For example, the potential can be easily detected by applying a probe to the pad 2a. Therefore, when a potential abnormality occurs, it can be detected early. It should be noted that one of the two pads 2a and 2a electrically connected to the common electrode 6 may be formed at a location that does not appear outside when the liquid crystal display device is completed. This is because the potential of the common electrode 6 can be checked during the manufacturing process.

[0012]

According to the liquid crystal display device of the first aspect, a predetermined potential is applied to the common electrode through one of the pads reaching the common electrode, and the potential of the common electrode is applied through another pad reaching the common electrode. Can be measured. Therefore,
The electric potential of the common electrode can be confirmed, and eventually the electric potential abnormality can be detected early.

[Brief description of drawings]

1A and 1B show an embodiment of a liquid crystal display device of the present invention, FIG. 1A is a perspective view, and FIG. 1B is a circuit diagram showing a potential transmission path to a common electrode. is there.

2A and 2B show a conventional example of a liquid crystal display device, FIG. 2A is a perspective view, and FIG. 2B is a circuit diagram showing a potential transmission path to a common electrode.

[Explanation of symbols]

 1 First Substrate (TFT Substrate) 2a Pad 3a Wiring Film 4 Conductive Micropearl 5 Second Substrate (CF Substrate) 6 Common Electrode

Claims (1)

[Claims] 1. A first substrate having wiring formed on its surface,
The above-mentioned surfaces of the second substrate having a common electrode formed thereon are opposed to each other at a predetermined interval, a sealed space is formed between the surfaces, and a liquid crystal is sealed in the sealed space. In the liquid crystal display device in which a predetermined voltage is applied to the common electrode of the second substrate from the pad and the wiring film, the potential transmission path from the pad of the first substrate to the common electrode of the second substrate is Liquid crystal display device having a plurality