JPH06186588A - Liquid crystal display device - Google Patents

Abstract

(57) [Abstract] [Purpose] In a liquid crystal display device in which a pixel electrode is formed on an interlayer insulating film using an organic thin film, the distance between opposing substrates is kept constant without decreasing the reliability of the driver, and The purpose is to reduce the size of the board. [Structure] A pixel electrode is formed on an organic thin film, and at the same time, an organic thin film is formed on a seal portion where a driver is formed.

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.

[0002]

2. Description of the Related Art As a conventional example characterized in that a pixel electrode is formed on an organic thin film, Japanese Patent Publication No. 1-35351 can be cited. In this example, aluminum is used as the pixel electrode to form a reflective liquid crystal display device.

In general, when a driver is built in an active matrix substrate, the driver is arranged outside the adhesive portion (hereinafter referred to as a seal portion) between the substrates with respect to the pixel portion as in JP-A-64-68725. Moreover, in order to improve the moisture resistance of the driver, it is sealed with an organic resin film such as polyimide.

FIG. 4 shows the structure of the adhesive portion.
Generally, small spheres having a diameter of several μm called a gap material for keeping a constant distance between opposing substrates are scattered on the pixel portion and the adhesive portion. At this time, the diameter of the gap material may be changed between the pixel portion and the adhesive portion.

[0005]

With respect to the structure of the adhesive portion,
The conventional example has a problem that it is difficult to maintain a constant substrate distance in the vicinity of the boundary between the pixel portion and the adhesive portion when the distance between the pixel portion and the adhesive portion is extremely different.

Further, if the driver is arranged outside, a space for the driver is required, and as a result, there is a problem that the area of the substrate is increased.

An object of the present invention is to provide a structure of a liquid crystal display device which can secure a uniform cell gap without reducing the reliability of a driver and can save space.

[0008]

The present invention provides an active matrix type liquid crystal display device with a built-in driver,
In the active matrix substrate, the source line and the pixel electrode are formed in a non-same layer through an interlayer insulating film such as polyimide resin, silicon oxide or silicon nitride, and the driver is formed in the bonding portion of the two substrates facing each other. And that the interlayer insulating film is formed also on the driver of the adhesive portion, a conductive thin film such as ITO is formed on the interlayer insulating film on the driver, and the conductive thin film has a common potential. And forming a conductive thin film also on the bonding portion of the counter substrate.

[0009]

1 is a plan view of a liquid crystal display device according to an embodiment of the present invention, and FIG. 2 is a sectional view taken along line XX '.
Shown in. A pixel switching TFT (hereinafter referred to as a pixel TFT) 1 is formed on an insulating substrate 101 such as a glass substrate.
02 is formed at the same time, and at the same time, a driving TFT for the pixel TFT group
(Hereinafter referred to as driver) 103 is formed. Next, as the interlayer insulating film 104, for example, polyimide is applied so as to have a film thickness of about 2 μm. After the polyimide is dried, a chrome thin film of about 1000 Å is deposited and patterned to form an etching mask 105. After that, the interlayer insulating film 104 is patterned by the dry etching method. At this time, the portion to be etched of the interlayer insulating film 104 is located outside the pixel electrode connection portion of the pixel TFT and the adhesion portion 110 (hereinafter referred to as a seal portion) with the counter substrate. After the etching is completed, the etching mask 105 is peeled off, and the pixel electrode 106
Formed by TO. At this time, ITO is also formed on the seal portion 110 to keep it at a common potential. Next, the insulating substrate 101
The opposite substrate 107 and the counter substrate 107 are adhered to each other at the seal portion 110, but at this time, they are adhered to each other with an adhesive containing a gap material. Finally, the liquid crystal mixed with the gap material is sealed.

Although chromium is used as the etching mask in the above embodiments, another material such as a silicon nitride film or a silicon dioxide film may be used as long as it serves as an etching mask.

Further, it is not always necessary to remove the etching mask, and it is possible to form the pixel electrode on the upper layer of the interlayer insulating film through the etching mask. In this case, since the etching mask removing step is omitted, damage to the interlayer insulating film can be further reduced. Further, if the photoresist is removed after the patterning of the etching mask, the etching mask is exposed to the etching gas and is easily damaged when the interlayer insulating film 104 is etched.
It is desirable to etch the interlayer insulating film without removing the photoresist.

The pixel electrode is not limited to ITO, for example, aluminum can be used.

The above is one embodiment of the present invention, but since the interlayer insulating film 104 is formed also in the seal part 110, there is almost no step between the pixel part 112 and the seal part 110. Therefore, it is not necessary to change the gap material of the seal portion and the gap material of the pixel portion, and it becomes easy to control the uniformity of the cell gap.

At the same time, the driver 103 has a seal portion 110.
Therefore, it is not necessary to reserve a space for the driver, so the space can be saved. Further, since the interlayer insulating film 104 on the driver 103 does not have to be removed, the driver is not damaged by etching. Further, in the conventional structure, it was necessary to finally seal the driver with polyimide, but when the present invention is used, the interlayer insulating film 1 is already formed.
Being covered with 04, no further sealing is necessary.

A conductive thin film 112 such as ITO exists on the interlayer insulating film 104 on the driver, and the conductive thin film 1
Since 12 has the same potential as the counter electrode 109, the reliability of the driver is not deteriorated due to the polarization of the adhesive or the organic thin film.

Further, since the counter electrode, which has been dropped to the common potential, is positioned on the driver through the adhesive of the seal portion, the electric field shielding effect is enhanced. Therefore, even if an external electric field is applied, the adverse effect on the driver and the wiring around the driver can be reduced, and as a result, the influence on the display quality is reduced.

[0017]

According to the present invention, the driver can be saved in the space because it is located in the seal portion. Further, since the interlayer insulating film having the same film thickness is formed on the driver together with the pixel portion, there is almost no step between the pixel portion and the seal portion. Therefore, since the gap material diameters of the pixel portion and the seal portion are the same, the cell gap is uniform The property is improved.

Since the driver is also protected by the conductive thin film having a common potential on the interlayer insulating film, the adverse effect of the external electric field can be reduced.

[Brief description of drawings]

FIG. 1 is a plan view of a liquid crystal display device described in an embodiment.

FIG. 2 is a cross-sectional view taken along line XX ′ of the liquid crystal display device described in the embodiment.

FIG. 3 is a cross-sectional view showing a process of an example.

FIG. 4 is a cross-sectional view of a conventional liquid crystal display device.

[Explanation of symbols]

 101 glass substrate 102 pixel TFT 103 driver 104 interlayer insulating film 105 etching mask 106 pixel electrode 107 counter substrate 108 adhesive 109 counter electrode 110 seal part 111 pixel part 112 conductive thin film

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location H01L 29/784

Claims (1)

[Claims] 1. In an active matrix type liquid crystal display device with a built-in driver, a source line and a pixel electrode of an active matrix substrate are formed in a non-same layer through an interlayer insulating film such as polyimide resin or silicon oxide or silicon nitride. Is formed on an adhesive portion of two substrates facing each other, the interlayer insulating film is also formed on a driver of the adhesive portion, and a conductive thin film such as ITO is formed on the interlayer insulating film on the driver. The liquid crystal display device is characterized in that the conductive thin film is applied with a common potential, and the conductive thin film is also formed on the adhesive portion of the counter substrate.