JPH06186579A - Liquid crystal display device - Google Patents

Abstract

PURPOSE:To reduce the deterioration of liquid crystal extending for a long period of time by using transparent organic insulating film in second inter-layer insulating film, leaving the organic insulating film in the lower part of a sealing area, arranging a driver circuit on the outer side than an opposed substrate, and providing organic film on the driver circuit. CONSTITUTION:An opposed substrate 302 is fixed on an element substrate 301 with a sealing material 303 of UV curing resin, etc., and liquid crystal is sealed in it. The driver circuit 304 is arranged on the outer side than the sealing area. Also, a thin film transistor 303 for picture element driving is formed on the substrate 301. The driver circuit 304 consisting of the integrated circuit of transistors is arranged on the outside of the sealing area 303, and an area from the picture element area of the element substrate to the lower part of the sealing area 303 is covered with the transparent organic insulating film 319 of polyimide, etc. Furthermore, a picture element electrode of ITO 314, etc., is formed on the transparent organic insulating film 319, and it is connected to the drain electrode of a picture element transistor via a contact hole 315.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an active matrix type liquid crystal display device.

[0002]

2. Description of the Related Art An example of a conventional liquid crystal display device will be described with reference to FIG.

This figure is an external view of a liquid crystal display device.

A pixel area 105 is arranged on a substrate 101 made of glass, quartz or the like as shown in FIG. 1A, and driver circuits 103 and 104 composed of thin film transistor integrated circuits are arranged around the pixel portion. The counter substrate 102 is
The pixel area 105 and the driver circuits 103 and 104 are fixed to the substrate 101 by a sealing material 106 such as an ultraviolet curable resin so that the edge thereof is located between the driver areas 103 and 104. The potential of the transparent electrode of the counter substrate is fixed to the common potential through the pad 107 on the substrate side by the conductive adhesive.

This is to prevent water and the like from flowing into the liquid crystal sealed between the element substrate 101 and the counter substrate 102 as much as possible, and further, a wiring having the same potential as the power source is provided in the driver circuit or its periphery. This is because an electric field is not applied to the liquid crystal due to this.

FIG. 1 (b) is a sectional view of the structure taken along the line AA 'in FIG. A thin film transistor 113 made of polycrystalline silicon or the like is formed on the substrate 101. The thin film transistor, the source line, and the pixel electrode 114 are covered with the second interlayer insulating film 120, but the upper portion of the pixel electrode 114 is opened. The gate electrode of this transistor is finally connected to the wiring 117 at the terminal end portion 116 through the contact hole, and the wiring 117 is connected to the driver circuit 103 formed of an integrated circuit of the transistor formed outside the end portion of the counter substrate. is doing.

A transparent electrode 111 is formed on the entire surface of the counter substrate 102, and a sealing material 106 such as an ultraviolet curable resin is formed.
It is fixed to the substrate by. Substrate 101, counter substrate 1
02 is covered with an alignment film 112 such as polyimide.

Further, FIG. 1C shows a structural sectional view taken along the line BB 'in FIG. Wirings 306 are formed on the first interlayer insulating film 119 on the substrate 101, and these are further covered with a second interlayer insulating film 120 of silicon oxide or the like, but the pads 107 and the upper portions of the pixel electrodes 114 are opened. It has a hole. An alignment film 112 of polyimide or the like is applied on this. Since the pad 107 is wired so as to have a common potential, when a conductive adhesive 118 is applied to this portion and the counter substrate 102 is pressure-bonded, the counter electrode 1 of the counter substrate 1 is formed.
As a result, 11 becomes the common potential.

Further, FIG. 2A is a perspective view of the above-mentioned liquid crystal display device, but the number of wirings traversing the seal area is as large as about 2 to 4 times the number of pixels. FIG. 2B is a cross-sectional view of the source wiring that crosses this seal. The source wiring formed on the first interlayer insulating film is 800
It is about 0Å aluminum and is covered with silicon oxide of 1 μm or less.

[0010]

However, in the conventional technique, since the driver circuit is arranged outside the seal area, the number of wirings crossing the seal area is as large as twice the number of pixels or more, and the step is tight. There was a possibility of inflow of water etc. that deteriorates the liquid crystal.

[0011]

According to the present invention, a transparent organic insulating film is used for the second interlayer insulating film, the organic insulating film is left below the seal area, and the driver circuit is arranged outside the counter substrate. The organic film is provided on the circuit.

[0012]

EXAMPLES The present invention will be described in detail based on the following examples.

FIG. 3A is a front external view of an example of the liquid crystal display device according to the present invention. A counter substrate 302 is fixed on an element substrate 301 by a sealing material 303 such as an ultraviolet curable resin, and a liquid crystal is sealed therein. Driver circuit 30
4 is arranged outside the seal area. The electrodes 305 at the four corners are for conducting to give a potential to the counter electrode of the counter substrate, and the potential is fixed to a certain potential given from the external connection terminal 306 of the element substrate by using a conductive adhesive or the like. It

FIG. 3B is a structural sectional view from the pixel area to the seal area. A pixel driving thin film transistor 313 is formed over the substrate 301. A driver circuit 304 composed of an integrated circuit of transistors is arranged outside the seal area, and a transparent organic insulating film 319 made of polyimide or the like covers the pixel area and the lower part of the seal area of these element substrates. A pixel electrode such as ITO 314 is formed on the transparent organic insulating film, and is connected to the drain electrode of the pixel transistor through the contact hole 315.

FIG. 3C is a structural sectional view from the pixel area to the seal area.

The potential of the counter substrate 302 is equal to that of the conductive adhesive 3
An electrode 305 made of ITO or the like on the transparent organic insulating film through 20
Further, this electrode is connected to a wiring 318 having a common potential located therebelow and fixed to the common potential.

Further, FIG. 4 shows a cross-sectional view of wiring crossing the seal in this liquid crystal display device. Since the organic film has less stress and does not have a problem such as cracking even if it is applied thicker than silicon oxide, the source wiring can be sufficiently embedded, so that the surface becomes smoother than silicon oxide.

[0018]

By adopting the structure of the liquid crystal display device of the present invention, the unevenness of the lower part of the seal area is small, the inflow of water and the like into the enclosed liquid crystal is reduced, and the deterioration of the liquid crystal is reduced over a long period of time and the reliability is improved. A high liquid crystal display device can be provided.

[Brief description of drawings]

FIG. 1 is an external view showing the structure of a conventional liquid crystal display device.

FIG. 2 is a perspective view showing the structure of a conventional liquid crystal display device.

FIG. 3 is a sectional view showing a structure of a liquid crystal display device according to the present invention.

[Explanation of symbols]

101, 201, 301 ... Element substrate 102, 202, 302 ... Counter substrate 113, 207, 313 ... Pixel driving transistor 116, 316, ... Pixel driving transistor gate electrode and gate wiring 106, 205, 303 ... Seal area 103, 104, 203, 204, 304 ... Driver circuit 117, 317 ... Wiring 105 ... Pixel area 114, 314 ... Pixel electrode 111, 311 ... Opposed Electrodes 318 ... Wirings having common potential 107, 305 ... Pads 110 having common potential 110, 310 ... Black matrix 115, 315 ... Contact holes with pixel electrodes 118, 320 ... Conductive adhesion Agent 319 ... Transparent organic insulating film 112, 312 ... Alignment film 119 ... First layer Insulating film 120 ... second interlayer insulating film 108,206,306 ... external connection terminal

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI Technical display location G02F 1/136 500 9018-2K G09G 3/36 7319-5G H01L 29/784

Claims (4)

[Claims] 1. A liquid crystal display device, comprising: an element substrate of the liquid crystal display device, wherein a pixel driving thin film transistor is covered with an organic film, and a pixel electrode is formed on the organic film. 2. The liquid crystal display device according to claim 1, wherein the organic film is provided below the seal area. 3. The liquid crystal display device according to claim 2, wherein the driver circuit is arranged on the outer periphery of the seal area. 4. The liquid crystal display device according to claim 3, wherein the organic film is provided at least on the driver circuit and no electrode is provided on the upper layer.