JP2609087B2 - Liquid crystal display device - 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 used for word processors, portable personal computers, TVs, and the like.
In addition, the present invention relates to a liquid crystal display element which prevents the generation of bubbles when left at a low temperature, and is particularly suitable for a large liquid crystal display device.

[0002]

2. Description of the Related Art In general, in a liquid crystal display device, a pair of substrates on which electrodes are formed are opposed to each other on an electrode surface, a spacer is provided between the substrates to form a predetermined gap, and a peripheral portion is held by a sealing material and the gap is maintained. Liquid crystal is sealed in the inside. In the liquid crystal display device, the thickness of the liquid crystal layer is usually about 5 to 15 μm, and if the gap is not maintained uniformly, color unevenness occurs on the display surface, resulting in poor display quality. Therefore, the spacer plays an important role in determining the display quality. As the spacer, a fibrous rigid spacer or a particulate elastic spacer has been used alone. But,
When a large-sized substrate having a display area of 10 cm 2 or more is used to manufacture a liquid crystal display element in which a fibrous rigid spacer is inserted in a liquid crystal, the gap between the substrates becomes substantially uniform, but bubbles are generated when left at a low temperature. The display quality was very poor. In addition, there is a liquid crystal display element using a particulate elastic spacer instead of a fibrous rigid spacer in order to address the above-mentioned drawbacks. The unevenness was larger than the gap in the spacer, and the display quality was poor.

Further, Japanese Patent Application Laid-Open No. 57-70520 discloses that a rigid spacer and a spacer having a softening point lower than that of the rigid spacer are mixed, and the mixture is dispersed on a substrate coated with an insulating film and heated to thereby reduce the softening point. A configuration in which a gap is made uniform by melting and fixing a low spacer and an insulating film is disclosed. That is, in the above publication, the spacer having a low softening point is a heat-resistant temperature of 350 ° C. of glass as a substrate material.
Using a polymer spacer with a melting point of about 200 ° C, which has the following melting point, spraying on the substrate, and then sealing the pair of substrates. At this time, the polymer spacer is melted and the insulation formed on the substrate is melted. The film and the polymer spacer are fused and fixed to make the gap between the substrates uniform.

[0004]

However, the above publication discloses that the melting temperature of the spacer is too high with respect to the curing temperature of the sealing material of about 120 ° C., that the melting temperature of the polymer spacer is difficult to control, and that the pressurization / heating is difficult. Has a problem that the seal baking apparatus cannot be simplified.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned drawbacks, to provide a liquid crystal display element having uniform intervals and free from bubbles, and to produce a liquid crystal display element without applying a temperature higher than the curing temperature of a sealing material. Accordingly, it is an object of the present invention to provide a liquid crystal display device having improved display quality.

[0006]

According to the present invention, there is provided a liquid crystal display device in which liquid crystal is sealed between a pair of opposing substrates, wherein spacers having different diameters are interposed between the substrates to form a large-diameter spacer. The spacer is capable of elastic deformation corresponding to the difference in diameter between the spacers, and when the large-diameter spacer is elastically deformed, the distance between the two substrates is limited by the small-diameter spacer. is there.

[0007]

In the liquid crystal display device of the present invention, spacers having different diameters are interposed between the substrates. When the liquid crystal contracts at a low temperature and the distance between the substrates is reduced, the large-diameter spacer is elastically deformed corresponding to the difference in diameter between the spacers, and thereafter, the distance between the substrates is limited by the small-diameter spacer. When the liquid crystal contracts, the large-diameter spacer is elastically deformed, and the distance between the substrates is reduced, so that the generation of bubbles in the liquid crystal can be prevented. After the elastic deformation, the spacing between the substrates becomes uniform by the small-diameter spacer.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a plan view of a liquid crystal display device according to the present invention in which two types of spacers having different diameters are provided in a liquid crystal, and FIG. 2 is a cross-sectional view of FIG. A glass fiber spacer 4 (diameter 7 μm ± 0.5 μm, length 20 μm) as a fibrous rigid body spacer is placed on one substrate 1 having a pair of transparent electrode films.
To 200 μm) and a particulate plastic bead spacer 5 (diameter: 8 μm ± 0.5) exhibiting a value closer to the expansion coefficient of the liquid crystal than the rigid spacer as the particulate elastic spacer.
μm) was applied at an approximate 1: 1 ratio. The other substrate 2 is screen-printed with an epoxy-based seal material 3 and both substrates are superimposed, and the seal material 3 is heated to a suitable temperature of about 120 ° C.
Heat and sinter at ~ 150 ° C and pressurize at a pressure of about 1 kg / square cm. In the gap between the substrate 1 and the substrate 2 of the liquid crystal display substrate thus obtained, the liquid crystal 6 is inserted through the injection hole 3a formed by cutting a part of the sealing material 3 in the substrate 2.
In the liquid crystal display element produced by injecting and sealing, the gap between the substrates was almost uniform, and no air bubbles were generated when left at a low temperature of -30 ° C. for about 48 hours.

That is, in the liquid crystal display element according to the present invention, the spacer is used without being melted, the gap between the substrates is regulated by the rigid spacer, and the generation of air bubbles is controlled by the elastic spacer having a diameter larger than that of the rigid spacer. A rigid spacer and a spacer having a low softening point, which are disclosed in JP-A-57-70520, are mixed and dispersed on a substrate coated with an insulating film to form a spacer having a low softening point and an insulating film. Has a configuration different from the configuration in which the gap is made uniform by fusing and fixing.

[0010]

As described above, according to the present invention, spacers having different diameters are provided in the gap between the substrates of the liquid crystal display element, and the large-diameter spacers can be elastically deformed corresponding to the difference in the diameters of the spacers. Thus, the gap between the substrates of the liquid crystal display element can be made uniform, and particularly, the gap between the large liquid crystal display elements having a display area of 400 square cm or more can be made uniform, and the generation of air bubbles when left at low temperature can be prevented. This has the effect of preventing pixel omission due to bubbles, which is a major factor in lowering the yield of display elements.

[Brief description of the drawings]

FIG. 1 is a plan view of a liquid crystal display device of the present invention in which two types of irregular spacers are provided in a gap between substrates.

FIG. 2 is a sectional view of FIG. 1,

[Explanation of symbols]

 1, 2 Substrate on which electrodes are formed 3 Sealing material 4 Glass fiber spacer 5 Plastic bead spacer 6 Liquid crystal

Claims (1)

(57) [Claims] In a liquid crystal display device in which liquid crystal is sealed between a pair of opposed substrates, spacers having different diameters are interposed between the substrates, and a large-diameter spacer has a diameter between the spacers. The liquid crystal display element is characterized in that an elastic deformation corresponding to the difference is made possible, and when the large-diameter spacer is elastically deformed, the distance between the two substrates is limited by the small-diameter spacer.