JPS62280722A - Liquid crystal display device - Google Patents

Abstract

PURPOSE:To obviate the generation of foams in the parting part for a display by preliminarily setting the nuclei to generate foams at a specific position and generating foams at a low temp. only in the place of the nuclei. CONSTITUTION:This liquid crystal display device is obtd. by forming oriented polyimide films 2 on upper and lower substrates 1 on which transparent electrodes are formed, printing a sealing part 4 to the substrate to one side, dispersing spacers of a suitable size to another substrate facing said substrate, combining the substrates, injecting a liquid crystal therebetween and sealing an injection port. The prescribed point 3 to be generated with the foam is constituted of a glass surface and ITO surface and is formed to have the wettability with the liquid crystal inferior to the wettability at the point of the display part constituted of the polyimide surface; therefore, the foam is generated only in the prescribed point to be formed with the foam if such liquid crystal display device is rested for 25hr in a thermostatic chamber kept at -30 deg.C. The spacers are thereby dispersed in the cell at the density enough to control the inter-substrate spacing without generating the foam in the parting part of the display, by which the uniform inter-substrate spacing is obtd.

Description

Detailed Description of the Invention 3. Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a liquid crystal display device that can be used even at low temperatures.

[Conventional technology]

When a liquid crystal display device is left at low temperatures, air bubbles are generated within the liquid crystal cells of the liquid crystal display device due to shrinkage of the liquid crystal. This phenomenon becomes a serious problem because as the size of liquid crystal display devices increases, the bubbles generated also become larger. In order to prevent the generation of bubbles, spacers within the cell are placed at a certain distance or more in order to keep the distance between the substrates that make up the liquid crystal cell constant, and the elasticity of the substrate glass is utilized to compensate for the volume of the liquid crystal that has shrunk. Alternatively, by using an elastic material (for example, polystyrene-based fine particles, polyamide-based fine particles, etc.) for the spacer in the cell, the spacer shrinks, which narrows the gap between the opposing substrates, and the liquid crystal Methods have been used to compensate for the shrinkage.

[Problem that the invention seeks to solve]

However, in order to achieve high contrast and high viewing angle of LCD devices, it is necessary to control the spacing between the substrates of LCD devices within 1%, and it is necessary to disperse the spacers in the cells with sufficient density. Therefore, this method of preventing bubble generation cannot be adopted, and bubbles are generated.

[Means for solving problems]

Therefore, in the liquid crystal display device of the present invention, the nucleus where bubbles are generated is set at a specific position, and at low temperatures, bubbles are generated only at this nucleus, so that bubbles are not generated within the display section. A liquid crystal display bag with special features! It is.

[Example 1] In a liquid crystal display device, opposing substrates are treated with multiple layers, each with different liquid crystal wettability, as shown in Table 1. As a result, specific areas where bubbles are generated can be formed using areas with poor wettability as cores.

FIG. 1 shows an embodiment of the invention. i! ! Polyimide orientation 11 (2
) and print a seal part (4) on one side of the base.

Distribute and combine spacers of appropriate size on the other opposing substrate. Furthermore, a liquid crystal display device was obtained by injecting liquid crystal and sealing the injection port. With this method, the predetermined bubble generation location (3) is made up of the glass surface and the 170th surface, and the wettability of the liquid crystal is worse than the location made of the polyimide surface of the display section. When this liquid crystal display device was left in a constant temperature bath at -30° C. for 25 hours, bubbles were generated only at predetermined bubble generation locations.

[Embodiment 2] FIGS. 2 and 3 show an embodiment of the present invention. An alignment film is applied to the upper and lower substrates (16) on which transparent electrodes are formed, and a sealant (7) mixed with a spacer (11) is applied by printing to one of the substrates. On the other opposing substrate, spacers (12) smaller by 0.5 to 2 μm than the spacers (11) mixed in the sealant are dispersed. With this method, at a predetermined bubble generation location (lO) where the sealant gap is narrow, the substrate spacing becomes larger than in other display sections. When this liquid crystal display device was left at -30° C. for 25 hours, bubbles were generated only at predetermined bubble generation locations.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to disperse the spacers in the cells with a sufficient density to control the substrate spacing without generating bubbles within the display section, and to maintain uniform substrate spacing. A liquid crystal display device was obtained. Note that this method can be applied not only to liquid crystal display devices but also to ECDs.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the structure of Embodiment 1 of the present invention. 1... Upper and lower boards 2...Polyimide alignment film 3...Predetermined bubble generation location 4...Seal part 5...Sealing part 2 and 3 are diagrams showing the structure of a second embodiment of the present invention. 6... Upper and lower boards 7...Seal part 8...Display section

Claims (1)

[Claims] In a liquid crystal display device having a liquid crystal cell and a liquid crystal in the cell, which is composed of at least one pair of electrode substrates facing each other, a nucleus for bubble generation due to contraction of the liquid crystal is provided outside the display parting part in the liquid crystal cell. Features a liquid crystal display device.