JPH06118404A - Liquid crystal display device - Google Patents

Abstract

PURPOSE:To obtain good moisture resistance and to eliminate the need for a special process for protecting driver circuits for driving thin-film transistors (TFTs) by making it possible to install the driver circuits right under the sealing part of the liquid crystal display device. CONSTITUTION:Transparent substrates 1, 2, the driver circuits 3 for driving the TFTs, wirings 4 formed by using metals, such as Cr, Al and Ta, org. adhesives 5, such as epoxy resins, input terminals 6 for the driver circuits 3, a liquid crystal layer 7, a counter electrode 8 consisting of a transparent conductive film consisting of ITO, etc., pixel electrodes 9 of the TFTs, source wirings of the TFTs and pixel electrodes 9 are insulated and separated to different layers and an insulating film 11 for protecting the driver circuits 3 is provided. Org. materials, such as polyimide, inorg. materials, such as SiO2, or combinations of the org. materials and the inorg. materials are used as this insulating film 11. Then, the formation of the driver circuit 3 for driving the TFTs right under the sealing parts of the liquid crystal display device is possible.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an active type liquid crystal display device which performs display by using liquid crystal sealed between two substrates.

[0002]

2. Description of the Related Art FIG. 3 is a view showing a joint portion of a conventional liquid crystal display device. 1 shows a liquid crystal display device including a transparent substrate 1 such as quartz or glass on which a thin film transistor and a driver circuit for driving the thin film transistor are formed, and a transparent substrate 2 on which a counter electrode is formed. Wiring 4 made of a metal such as Cr, Al, or Ta for transmitting the signal from 3 is shown. The driver circuit 3 is formed on the substrate 1 at the same time as the thin film transistor. In FIG. 3, reference numeral 5 denotes an organic adhesive such as epoxy resin that bonds the transparent substrates 1 and 2, and 6 denotes an input terminal to the driver circuit. FIG. 4 shows a cross section taken along the line AA in FIG. 3. In FIG.
Is a driver circuit for driving a thin film transistor, 4 is a wiring, 5 is an organic adhesive, 7 is a liquid crystal layer, 8 is a counter electrode made of a transparent conductive film such as ITO, 9 is a pixel electrode of a thin film transistor, and 6 is an input terminal. . Conventionally, the driver circuit 3 is formed outside the display unit 10 of the liquid crystal display device. However, this method requires a sealing material on the upper part of the driver circuit 3 in order to improve the moisture resistance and prevent damage of the driver circuit 3 on the outer peripheral portion. Further, as the liquid crystal display device becomes finer, the number of wirings 4 increases, water easily enters the liquid crystal layer 7 along the wirings 4, and deterioration of the liquid crystal display device starts to occur from the outer peripheral portion.

[0003]

The problem to be solved by the present invention is to provide a liquid crystal display by devising a structure that allows a driver circuit for driving a thin film transistor to be provided immediately below a sealing portion of a liquid crystal display device. It is to achieve the improvement of the reliability of the device and the improvement of the productivity.

[0004]

The liquid crystal display device of the present invention is to solve the above-mentioned problems, and the source wiring of the thin film transistor and the pixel electrode are insulated by an organic insulating film and formed in different layers. The organic insulating film is formed on the sealing portion of the liquid crystal display device and above the driver circuit for driving the thin film transistor, and the driver circuit is formed immediately below the sealing portion of the liquid crystal display device. It is characterized by

[0005]

The liquid crystal display device of the present invention will be described in detail below with reference to the embodiments shown in the drawings.

FIG. 1 is a diagram showing an embodiment of the liquid crystal display device of the present invention. In FIG. 1, 1 and 2 are transparent substrates and 3
Is a driver circuit for driving the thin film transistor, Cr,
Wirings 4, 5 made of metal such as Al or Ta are organic adhesives such as epoxy resin, 6 are input terminals of the driver circuit 3, 7 is a liquid crystal layer, 8 is a counter electrode made of a transparent conductive film such as ITO, Reference numeral 9 indicates a pixel electrode of the thin film transistor, and 11 indicates an insulating film for insulating the source wiring of the thin film transistor and the pixel electrode into different layers and protecting the driver circuit 3. As the insulating film 11, it is possible to use an organic material such as polyimide or acrylic, an inorganic material such as SiO ₂ or SiN _x , or a combination of the organic material and the inorganic material.

2A and 2B are a plan view and a sectional view of a thin film transistor used in the liquid crystal display device of the present invention. 1 is a transparent substrate, a channel region 12 of the thin film transistor, a gate insulating film 13 of the thin film transistor,
A source / drain region 14 of the thin film transistor, a gate wiring 15 of the thin film transistor, a source wiring 16 of the thin film transistor, a first insulating film 17 made of an inorganic material such as SiO ₂ or SiN _x for insulating the gate wiring 15 and the source wiring 16 from each other, The pixel electrode 9 of the thin film transistor, and the second insulating film 18 made of an organic material such as polyimide or acrylic that insulates the source wiring 16 and the pixel electrode 9 from each other are shown. The insulating film 11 in FIG. 1 is formed by using the second insulating film 18 in FIG.

According to this embodiment, since the driver circuit for driving the thin film transistor can be formed immediately below the sealing portion of the liquid crystal display device, a special sealing work for protecting the driver circuit is required. do not need. Further, at the position of the driver circuit shown in this embodiment, the driver circuit is not affected by the liquid crystal layer. Further, in this embodiment, by leaving a film such as ITO on the insulating film 11,
The gap between the substrates 1 and 2 can be accurately finished without the gap material mixed in the adhesive 5 being buried in polyimide or the like. Here, the reason for removing the counter electrode on the counter substrate side is to prevent a capacitance from being formed between the counter electrode and the ITO film left on the insulating film 11.

[0009]

As described above, the following effects can be obtained by the present invention.

(1). Since the wiring portion exposed outside the display portion of the liquid crystal display device is eliminated, a liquid crystal display device having excellent moisture resistance can be obtained.

(2). A driver circuit for driving a thin film transistor can be formed immediately below a sealing portion of a liquid crystal display device, and a special step for protecting the driver circuit is not required, and at the same time, the driver circuit is damaged when handling the liquid crystal display device ( It is possible to prevent scratches and wire breaks and improve yield.

(3). Since the wiring length between the driver circuit for driving the thin film transistor and the thin film transistor can be shortened, the liquid crystal display device can be downsized.

[Brief description of drawings]

FIG. 1 is a diagram showing an example of a liquid crystal display device of the present invention.

2A and 2B are a plan view and a cross-sectional view of a thin film transistor used in a liquid crystal display device of the present invention.

FIG. 3 is a diagram showing a joint portion of a conventional liquid crystal display device.

FIG. 4 is a sectional view of an AA portion in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ...- Transparent substrate on which a thin film transistor is formed 2 ...- Transparent substrate on which a counter electrode is formed 3 ...- Driver circuit for driving a thin film transistor 4 ... Wiring 5 ... Organic adhesive 6 ... Input terminal of driver circuit 7 ... Liquid crystal layer 8 ... Counter electrode 9 ... Pixel electrode 10 ... Display portion of liquid crystal display device 11 ... Insulating film 12 .... Channel region of thin film transistor 13 ... Gate insulating film of thin film transistor 14 ... Source / drain region of thin film transistor 15 ... Gate wiring of thin film transistor 16 ... Source wiring of thin film transistor 17 ... .... First insulating film 18 ... Second insulating film

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kiyofumi Kitawada 3-5 Yamato, Suwa, Nagano Seiko Epson Corporation (72) Inventor Tsutomu Hashizume 3-5 Yamato, Suwa, Nagano Prefecture Seiko Epson Co., Ltd. (72) Inventor Yoshiyuki Kitazawa 3-5 Yamato, Suwa, Nagano Seiko Epson Co., Ltd. (72) Inventor Junri Shimone 3-5 Yamato, Suwa, Nagano Seiko Epson Corporation (72) Inventor Satoshi Inoue 3-5-3 Yamato, Suwa-shi, Nagano Seiko Epson Corporation

Claims (4)

[Claims] 1. A substrate on which a thin film transistor and a driver circuit for driving the thin film transistor are formed, and an opposite substrate on which an opposite electrode is formed are sealed with an organic adhesive and sealed between the two substrates. A liquid crystal display device that performs display using the generated liquid crystal, wherein the driver circuit is formed immediately below a sealing portion of two substrates. 2. The liquid crystal display device according to claim 1, wherein the source wiring and the pixel electrode of the thin film transistor are insulated by an organic insulating film and are formed in different layers. 3. The liquid crystal display according to claim 1, wherein the organic insulating film and the pixel electrode are formed on a sealing portion of the two substrates and on an upper portion of the driver circuit. apparatus. 4. The liquid crystal display device according to claim 1, wherein the counter electrode of the counter substrate is removed only at a sealing portion of the two substrates.