JPH06138490A - Liquid crystal display device - Google Patents

Abstract

PURPOSE:To use stable and high picture quality for a long period by electrically connecting a transparent conductive film formed on driving circuits to a counter electrode. CONSTITUTION:An X-side driving circuit 102 and a Y-side driving circuit 103 consisting of thin film transistors are constituted on the glass substrate 101, and those driving circuits are arranged between the liquid crystal sealing part 104 and glass substrate 101. Electric conductors for a block signal; a video signal, etc., are connected to the X-side driving circuit 102 and extended to an external terminal 111 through the liquid crystal sealing part 104. Further, electric conductors for the clock signal, etc., are connected to the Y-side driving circuit 103 as well and extended to an external terminal 112. An organic thin film is adhered and formed on the X-side driving circuit 102 and Y-side driving circuit 103 and a conductive thin film 114 made of the same material with pixel electrodes 107 is adhered and formed on the organic thin film. Further, a common electrode adhered to an opposite substrate 113 and the conductive thin film 114 are electrically connected by a conductive material 115.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a display device, and more particularly to a liquid crystal display device having a non-linear element.

[0002]

2. Description of the Related Art Active matrix type liquid crystal display devices, which are influential flat displays, have begun to be mass-produced. The flat display occupies a small space,
Due to its light weight, it is used for display devices of portable computers and display parts of industrial machines. In the future, the screens will become larger and the definition will become higher, and it is expected that home-use televisions will be applied. In a liquid crystal display device using a thin film transistor as a drive element, there is a method of forming a drive circuit on the same substrate as a pixel as a powerful means for achieving high definition. FIG. 5 is a perspective view showing a part of the structure of a conventional liquid crystal display device with a built-in drive circuit in an easily understandable manner. FIG. 5 is an imitation view of a liquid crystal display device as if the counter substrate was partially cut away.

An X-side drive circuit 502 composed of thin film transistors and a Y-side drive circuit 503 are formed on a glass substrate 501.
Is formed outside the sealing portion 504, and the data line 505 is connected from the X side drive circuit 502 to the Y side drive circuit 50.
3 from the gate line 506, respectively the sealing portion 504
This data line 5 extends through the
A thin film transistor for giving a signal to the pixel 507 is formed at the intersection of 05 and the gate line 506. The source region of the thin film transistor and the data line 505 pass through the through hole 508, and the drain region and the pixel electrode 5
07 are electrically connected to each other through through holes 509. The signal on the data line 505 is transmitted to the pixel electrode 507 by the potential of the gate electrode 510.

External terminals 511 and 512 are connected to the X-side drive circuit and the Y-side drive circuit. A video signal necessary for image display, a clock signal for driving a driving circuit, and a driving potential signal are transmitted to the external terminal.

Substrate 50 on which picture element electrodes 507 are formed
A liquid crystal is sealed between 1 and the counter substrate 513 on which the common electrode is formed to form an active matrix liquid crystal display device.

FIG. 6 shows a plan view of a substrate on which the pixel electrodes of the liquid crystal display device of FIG. 5 are formed. X side drive circuit 60
2 and the data line 605 extending from 2 and the Y side drive circuit 60
The gate lines 606 extending from 3 reach the display area through the liquid crystal sealing unit 604, and the data lines 60
A thin film transistor is formed at the intersection of 5 and the gate line 606.

FIG. 7 is a schematic plan view of an active matrix substrate. Data line 705 and gate line 70
A thin film transistor 716 for switching a pixel is formed at the intersection of six. The number of pixels required to sufficiently express a moving image is about 400 columns on the X side and about 300 rows on the Y side. Then, in the case of a liquid crystal display device having a built-in drive circuit as in the conventional art, 400 or more data lines and 300
A structure in which more than one gate line passes through the liquid crystal sealing portion 704 has been adopted.

Further, FIG. 8 shows a schematic view of a cross section taken along the line AA ′ in FIG. 6 in the vicinity of the liquid crystal sealing portion of the conventional liquid crystal display device.

A thin film transistor is formed on a glass substrate 801, and a pixel electrode 8 is formed in its drain region 817.
07 is connected. The pixel electrode 807 is deposited on the interlayer insulating film 818 made of a silicon oxide film. Liquid crystal 821 is sealed between the counter substrate 813 on which the common electrode 820 is formed and the glass substrate 801. Further, the drive circuit is formed outside the liquid crystal sealing unit 804.

[0010]

However, in the structure of the above-mentioned conventional liquid crystal display device, there are several hundreds of wirings passing through the liquid crystal sealing portion, including the data line and the gate line.
Therefore, in a high-temperature and high-humidity environment, components such as water, carbon dioxide, and nitric oxide enter from the interface between the data line or gate line and the liquid crystal encapsulation, which causes the liquid crystal to deteriorate and display characteristics to significantly deteriorate. There is a problem that the liquid crystal display device cannot be used for a long period of time.

[0011]

In a liquid crystal display device in which a liquid crystal is sandwiched between a plurality of transparent substrates and a non-linear element is formed on at least one substrate, a pixel electrode formed by a transparent conductive film is A driving circuit formed of a thin film transistor that drives a non-linear element that gives a signal to a pixel electrode is formed on a thin film, and is internally formed of a liquid crystal sealing portion of a liquid crystal display device. An organic thin film and a transparent conductive film are sequentially formed on the driving circuit of, and the transparent conductive film and the counter electrode formed on the driving circuit are electrically joined. Liquid crystal display device characterized by.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, specific embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a schematic perspective view showing the internal structure of the liquid crystal display device in an easy-to-understand manner and showing a part of the counter substrate.

An X-side drive circuit 102 and a Y-side drive circuit 10 in which a thin film transistor circuit is assembled on a glass substrate 101.
3 are configured. These drive circuits are the liquid crystal sealing unit 1.
It is arranged on the display area side inside 04. A data line 105 extends from the X side drive circuit and a gate line 106 extends from the Y side drive circuit to the display region. The data line 105 is provided with a through hole 108 in the source region of the thin film transistor for switching the pixel 107 in the display region.
, And the drain region of the thin film transistor is electrically connected to the pixel 107 through the through hole 109. The gate line 106 is
The gate electrode 110 of each thin film transistor also serves as the switching of this display region. A liquid crystal is sandwiched between a glass substrate 101 on which a thin film transistor is formed and a counter substrate 113 on which a common electrode is formed.
Enclosed in 4. Furthermore, in the X side drive circuit 102,
Wirings for clock signals, video signals, etc. are connected, pass through the liquid crystal sealing unit 104, and are connected to the external terminals 111. Similarly, in the Y-side drive circuit as well, wirings for clock signals and the like are connected to the external terminals 112. An organic thin film is deposited on the X-side drive circuit and the Y-side drive circuit, and a conductive film 114 made of the same material as the pixel electrode is deposited on the organic thin film.

Further, the common electrode deposited on the counter substrate 113 and the conductive film 114 are electrically joined by the conductive material 115.

FIG. 2 shows an enlarged plan view of a part of the active matrix substrate in which the thin film transistor of the liquid crystal display device of the invention is formed. The drive circuit is the liquid crystal sealing unit 2
The X side drive circuit 20 is configured on the display area side inside 04.
A thin film transistor is formed at the intersection of the data line 205 extending from 2 to the display area and the Y side driving circuit 203 to the gate line 206. In addition, wiring 211 necessary for a driver circuit that supplies a video signal, a clock signal, and the like,
212 extends from the drive circuit to the outside. Further, in order to increase the aperture ratio of the pixel electrode, a part of the gate line and the pixel electrode are overlapped with each other, and further, a part of the source line and the pixel electrode are overlapped with each other. In other words, the gate line and the data line are
In a region other than the picture element portion of the display region, it serves as a light-shielding film that blocks light incident from the back surface of the active matrix. At this time, since the organic thin film having a thickness of 1 μm or more is formed between the gate line or the source line and the pixel electrode, the distortion of the signal applied to the pixel electrode hardly occurs.

FIG. 3 shows a schematic plan view of an active matrix substrate in which the pixel electrodes of the liquid crystal display device of FIG. 1 are formed.

From the X-side drive circuit 302 to the data line 30
5, the gate line 306 extends from the Y-side drive circuit 303 to the display region, and the thin film transistor 316 and the pixel electrode are formed at the intersection of the data line and the gate line.

Since the driving circuit is formed inside the liquid crystal sealing portion 304 on the display area side, hundreds of data lines 305 extending from the X side driving circuit 302 and the number extending from the Y side driving circuit 303. The hundred gate lines 306 do not pass through the liquid crystal sealing unit 304.

Since there is almost no wiring that passes through the liquid crystal sealing portion, the amount of water and gas that cause deterioration of the liquid crystal that enters the display area is extremely reduced. Therefore, it has become possible to use a stable and high-quality liquid crystal display device for a long period of 10 times or more than before.

Next, FIG. 4 shows a sectional view of the active matrix substrate taken along the line AA 'in FIG. In this figure, an interlayer insulating film which cannot be represented in FIG. 1 is shown. A drive circuit 402 formed of a thin film transistor is formed on the glass substrate 401 on the display region side of the liquid crystal sealing portion. A pixel 407 to which a signal is applied by the thin film transistor in the display region is an interlayer insulating film 418 made of a silicon oxide film.
And is formed on the organic thin film 419.

By forming the organic thin film 419, the surface of the display region becomes flat, and the picture element electrode 407 is formed on this flat plane. Therefore, the distance between the common electrode 420 of the counter substrate 413 and the picture element electrode 407 is different. Since the parts are even,
The liquid crystal has the same degree of rotation, which enables uniform high-quality display.

[0023]

As shown in FIG. 8 of the conventional example, when the picture element electrode 807 is formed directly on the interlayer insulating film 818, the picture element electrode 807 is formed according to the vertical shape of the interlayer insulating film 818.
Since the cross-sectional shape has a step and the interval between the common electrode 820 and the pixel electrode 807 is non-uniform, the display characteristics are uneven. However, as in the present invention, the organic thin film 419 on the interlayer insulating film 418 has a flat surface regardless of the cross-sectional shape of the interlayer insulating film 418. Therefore, the pixel electrode 40 formed on the organic thin film 419 having a flat surface.
7 has a flat cross section, and the distance between the pixel electrode 407 and the common electrode 421 is uniform over the entire display area.
A high-contrast display with no display unevenness can be obtained.

On the driving circuit, there is a conductive film 414 formed at the same time as the pixel electrodes with the organic thin film 419 interposed therebetween.
This conductive film passes through the conductive material 415 and passes through the common electrode 42.
It is electrically connected to 0. As a result, static electricity generated around the drive circuit due to changes in the external environment flows into the common electrode, which has the advantage that the drive circuit can be protected from static electricity, and can be used even in a dry environment. Can be manufactured.

Further, the glass substrate 401 and the counter substrate 413
In order to adjust the distance between several .mu.m to several .mu.m, the particles with high hardness are scattered on the active matrix substrate on which the picture elements are formed, and the opposing substrates are superposed. At this time, even if the particles with high hardness are on the drive circuit, Since the drive circuit has the conductive film 414 made of the same material as the picture element, the drive circuit is not damaged.

Further, an organic thin film 419 is formed on the driving circuit.
And the interface between the organic thin film and the liquid crystal encapsulation are also in good contact, so moisture and gas that cause deterioration of the liquid crystal do not enter the liquid crystal from the external environment, maintaining high quality display characteristics for a long time. can do.

Further, a conductive film made of the material of the pixel electrode is formed at the same time as the pixel electrode on each of the X-side and Y-side drive circuits with the organic thin film 419 interposed therebetween. This makes the top of the drive circuit of the active matrix substrate the same as the top of the display area, so when applying the liquid crystal aligning agent to the substrate and rubbing with a roll, the edge of the display area The rubbing unevenness was eliminated, and a screen with high quality display characteristics could be realized over the entire display area.

Further, in the case of the conventional liquid crystal display device in which the drive circuit is formed on the same substrate, since the drive circuit is formed outside the liquid crystal sealing portion, the number of data lines and gate lines is almost the same. Since the wiring passed through the liquid crystal encapsulation part, gas or water that deteriorates the liquid crystal enters the display area from the interface between the step part of the data line or gate line and the liquid crystal encapsulation part, and deteriorates the liquid crystal characteristics. However, there is a problem that display characteristics are deteriorated.

However, in the structure of the present invention, the number of wirings passing through the liquid crystal sealing portion is 20 at most, which is 1/40 or less of the conventional one, so that the gas and water entering the display area are significantly reduced. For this reason, it has become possible to manufacture a high-quality liquid crystal display device that can be used for a significantly longer period of time than ever before.

[Brief description of drawings]

FIG. 1 is a perspective structural view of a liquid crystal display device of the present invention.

FIG. 2 is a plan view of an active matrix substrate of a liquid crystal display device of the present invention.

FIG. 3 is a schematic plan view of an active matrix substrate of a liquid crystal display device of the present invention.

FIG. 4 is a cross-sectional view of a liquid crystal display device of the present invention.

FIG. 5 is a perspective structural view of a conventional liquid crystal display device.

FIG. 6 is a plan view of an active matrix substrate of a conventional liquid crystal display device.

FIG. 7 is a schematic plan view of an active matrix substrate of a conventional liquid crystal display device.

FIG. 8 is a sectional view of a conventional liquid crystal display device.

[Explanation of symbols]

101, 201, 301, 401, 501, 601, 701, 801 ... Glass substrate 102, 202, 302, 402, 502, 602, 702, 802 ... X-side drive circuit 103, 203, 303, 503, 603, 703 ... Y-side drive circuit 104, 204, 304, 404, 504, 604, 704, 804 ... Liquid crystal sealing section 105, 205, 305, 505, 605, 705 ... Data line 106, 206, 306, 406, 506, 606, 706, 806 ... Gate lines 107, 207, 407, 507, 607, 807 ... Pixel electrodes 108, 208, 508, 608 ... Through holes in data lines and source regions 109, 209, 409, 509, 609, 809 ... Picture Through holes for element electrodes and gate lines 110, 210, 510, 610 ... Gate electrodes 111, 211, 311, 511, 611, 711 ... External wiring of X side drive circuit 112, 212, 312, 512, 612, 712 ... Y External wiring of side driving circuit 113, 413, 513, 813 ... Counter substrate 114, 414 ... Conductive thin film 115, 215, 315, 415 ... Conductive material 316, 716 ... Thin film transistor 417, 817 ... Drain region 418, 818 ... layers Insulating film 419 ... organic thin 420,820 ... common electrode 421,821 ... LCD

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yoshiyuki Kitazawa 3-3-5 Yamato, Suwa City, Nagano Seiko Epson Corporation (72) Inventor Junri Shimone 3-5 Yamato, Suwa City, Nagano Prefecture Seiko Epson Co., Ltd. (72) Inventor Hideyuki Akanuma 3-3-5 Yamato, Suwa, Nagano Seiko Epson Co., Ltd. (72) Inventor Takashi Nakazawa 3-3-5 Yamato, Suwa, Nagano Seiko Epson Corporation (72) Inventor Satoshi Inoue 3-5-3 Yamato, Suwa-shi, Nagano Seiko Epson Corporation

Claims (1)

[Claims] 1. A liquid crystal display device in which liquid crystal is sandwiched between a plurality of transparent substrates, and a non-linear element is formed on at least one of the substrates, and a pixel electrode formed of a transparent conductive film is formed on an organic thin film. The drive circuit for driving the non-linear element that gives a signal to the pixel electrode is configured inside the liquid crystal sealing part of the liquid crystal display device, and the organic thin film and the transparent conductive film are formed on the drive circuit. A liquid crystal display device, wherein films are sequentially formed by deposition, and a transparent conductive film formed on the drive circuit and an opposing electrode are electrically joined.