JP3203815B2 - Liquid crystal display - Google Patents

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 which performs display by driving a liquid crystal sandwiched between two substrates by using a thin film transistor.

[0002]

2. Description of the Related Art FIG. 5 is a view showing a joint portion of a conventional liquid crystal display device. Transparent substrate 1 on which thin film transistor is formed
And a liquid crystal display device comprising a transparent substrate 2 on which a counter electrode is formed, and a metal such as Cr, Al, Ta or the like for transmitting a signal from a driver circuit 5 for driving the thin film transistor formed on the substrate 1. 2 shows a wiring 3 using. The driver circuit 5 includes an LSI chip on the substrate 1
When it is soldered to the upper wiring 3 or when it is joined to the wiring 3 using an anisotropic conductive tape, it is also manufactured monolithically on the substrate 1 through the same manufacturing process as the thin film transistor. And so on. In FIG. 5, reference numeral 4 denotes an organic adhesive such as an epoxy resin for joining the substrate 1 and the substrate 2 together. FIG. 6 shows a cross section of the AA portion in FIG. 5. In FIG. 6, 1 is a transparent substrate on which a thin film transistor is formed, 2 is a transparent substrate on which a counter electrode is formed, 3 is Cr, Al, Ta, etc. Reference numeral 4 denotes an organic adhesive, 5 denotes a driver circuit for driving a thin film transistor, 6 denotes a liquid crystal layer, and 7 denotes a transparent electrode made of a transparent conductive film such as ITO. Conventionally, the flat substrate 1 and the substrate 2 are directly sealed with the organic adhesive 4. However, in this method, moisture easily penetrates into the liquid crystal layer 6 along the wiring 3, and the liquid crystal display device is deteriorated from the outer peripheral portion. In particular, the difference in the thermal expansion coefficient between the wiring 3 and the organic adhesive 4 is large, and a gap is likely to be formed at the joint between the wiring 3 and the organic adhesive 4.

[0003]

SUMMARY OF THE INVENTION The present invention has been made in a liquid crystal display device in which a liquid crystal is sandwiched between a pair of substrates bonded to each other by an adhesive, in order to suppress the penetration of moisture into the liquid crystal layer. The purpose is to improve the moisture resistance of the liquid crystal display device.

[0004]

According to a first aspect of the present invention, there is provided a liquid crystal display device having a liquid crystal display device in which a liquid crystal layer is sandwiched between a pair of substrates joined by an adhesive. A thin film transistor formed on one of the substrates, a driver circuit connected to the thin film transistor via a wiring, an insulating film formed on the wiring, and a surface of the insulating film facing the adhesive. An uneven portion extending in a direction intersecting with the wiring direction, wherein the adhesive is fixed to the uneven portion. Another liquid crystal display device of the present invention is a liquid crystal display device in which a liquid crystal layer is sandwiched between a pair of substrates bonded to each other by an adhesive, wherein the thin film transistor formed on one of the pair of substrates and the thin film transistor A driver circuit connected via a plurality of wirings, an insulating film formed between the plurality of wirings and the wiring, and a depth not reaching the wiring on a surface of the insulating film facing the adhesive. And the adhesive is fixed to the uneven portion.

[0005]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a liquid crystal display device of the present invention will be described in detail with reference to illustrated embodiments.

FIG. 1 is a sectional view of a joint portion of a liquid crystal display device according to an embodiment of the present invention. In FIG. 1, 1 is a transparent substrate on which a thin film transistor is formed, 2 is a transparent substrate on which a counter electrode is formed, 3 is a wiring using a metal such as Cr, Al, or Ta, 4 is an organic adhesive such as epoxy resin, 5 is a driver circuit for driving a thin film transistor, 6 is a liquid crystal layer, 7 is a transparent electrode made of a transparent conductive film such as ITO,
Reference numeral 8 denotes an insulating film on which unevenness has been processed. As the insulating film 8, it is possible to use an organic material such as a polyimide resin or an acrylic resin, an inorganic material such as SiO ₂ or SiN _X , or a combination of the organic material and the inorganic material.

FIG. 2 is a view taken in the direction of the arrow A in FIG.
In FIG. 2, 1 is a transparent substrate on which a thin film transistor is formed, 2 is a transparent substrate on which a counter electrode is formed, 3 is Cr,
Wiring using a metal such as Al or Ta, 4 is an organic adhesive such as epoxy resin, 5 is a driver circuit for driving a thin film transistor, and 8 is an insulating film processed into an uneven shape.
FIG. 3 shows an arrow view of a portion B in FIG. In FIG. 3, 1 is a transparent substrate on which a thin film transistor is formed, 2 is a transparent substrate on which a counter electrode is formed, and 3 is Cr, Al, Ta.
Reference numeral 4 denotes an organic adhesive such as an epoxy resin, and 8 denotes an insulating film having irregularities.

FIG. 4 is a sectional view of a thin film transistor used in the liquid crystal display device of the present invention. In FIG. 4, 1 is a transparent substrate on which a thin film transistor is formed, 9 is a channel region of the thin film transistor, 10 is a gate insulating film of the thin film transistor, 11 is a source / drain region of the thin film transistor, 12 is a gate wiring of the thin film transistor, 13 Denotes a source wiring of the thin film transistor, 14 denotes a first interlayer insulating film for insulating the gate wiring 12 and the source wiring 13, 15 denotes a pixel electrode of the thin film transistor, and 16 denotes a second interlayer insulating the source wiring 13 and the pixel electrode 15. 3 shows an insulating film. As the insulating film 8 in FIGS. 1, 2 and 3, at least one of the insulating films 14 and 16 in FIG. 4 is used. Further, the insulating film must have a sufficient thickness to embed the wiring 3 and to process unevenness, and the thickness of the insulating film depends on the properties of the liquid crystal layer 6 used in the liquid crystal display device. It depends on the gap with the substrate 2 and the film thickness of the wiring 3. For example, when the gap between the substrate 1 and the substrate 2 is 5 μm and the thickness of the wiring is 0.5 μm, the thickness of the insulating film 8 is preferably about 1 μm to 3 μm.

According to the present embodiment, since the insulating film 8 with the unevenness is formed on the wiring 3 passing through the joint between the substrate 1 and the substrate 2, the adhesion to the adhesive 4 is improved. Become. The moisture from the outside air is removed from the insulating film 8 having the unevenness.
Flows along the joint surface between the and the adhesive 4 or
It flows either along the joint surface between the wiring 3 and the insulating film 8, but in any case, it is possible to make the water inflow path longer than in the conventional joining method, and therefore, The time until moisture reaches the liquid crystal layer 6 becomes longer, and the image quality hardly deteriorates.

Further, in the present embodiment, the joint portion between the substrates 1 and 2 is processed into an uneven shape at the joint portion between the substrates 1 and 2.
If the joint portion is also processed into a concavo-convex shape, even better results can be obtained.

[0011]

According to the present invention, the following effects can be obtained.

(1). In order to improve the adhesion of the substrate bonding part and to make the water inflow path longer,
A liquid crystal display device having good moisture resistance can be obtained.

(2). When manufacturing a driver circuit at the same time as manufacturing a thin film transistor for driving a liquid crystal, it is possible to protect the driver circuit with an insulating film, and damage (scratch,
Disconnection) can be prevented, and an improvement in yield can be expected.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating an example of a liquid crystal display device of the present invention.

FIG. 2 is an arrow view of a portion A in FIG.

FIG. 3 is an arrow view of a portion B in FIG. 1;

FIG. 4 is a cross-sectional view of a thin film transistor used in the liquid crystal display device of the present invention.

FIG. 5 is a diagram showing a joining portion of a conventional liquid crystal display device.

FIG. 6 is a sectional view of an AA part in FIG. 5;

[Explanation of symbols]

 1 ··· Transparent substrate on which thin film transistor is formed 2 ··· Transparent substrate on which counter electrode is formed 3 ··· Wiring 4 ··· Organic adhesive 5 ··· Driver circuit for driving thin film transistor 6 ··· Liquid crystal layer 7 ··· Transparent electrode 8 ··· Insulating film processed into an uneven shape 9 ··· Channel region of thin film transistor 10 ··· Gate insulating film of thin film transistor 11 ··· · Source / drain region of thin film transistor 12 ··· Gate wiring of thin film transistor 13 ··· Source wiring of thin film transistor 14 ··· First interlayer insulating film 15 ··· Pixel electrode of thin film transistor 16 ··· Second interlayer insulating film

Claims (2)

(57) [Claims] 1. A liquid crystal display device having a liquid crystal layer sandwiched between a pair of substrates joined to each other by an adhesive, wherein the thin film transistor is formed on one of the pair of substrates, and the thin film transistor is connected to the thin film transistor via a wiring. A driver circuit connected thereto; an insulating film formed on the wiring; and an uneven portion extending on a surface of the insulating film facing the adhesive in a direction intersecting the wiring direction. A liquid crystal display device, wherein the adhesive is fixed to a portion. 2. A liquid crystal display device in which a liquid crystal layer is sandwiched between a pair of substrates joined to each other by an adhesive, wherein a thin film transistor formed on one of the pair of substrates and a plurality of wirings are provided on the thin film transistor. A plurality of driver circuits connected to each other via an interconnect, an insulating film formed on the plurality of wirings and between the wirings, and an uneven portion having a depth not reaching the wirings on a surface of the insulating film facing the adhesive. A liquid crystal display device comprising: the adhesive agent fixed to the uneven portion.