JPS6029089B2 - liquid crystal display device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to the use of a glass classified as intermediate between soda lime glass and shelf silicate glass for the substrate of a liquid crystal display device.

An object of the present invention is to reduce the glass cost by using a glass whose alkali ion elution amount is between that of shelf silicate glass and soda lime glass as a substrate.

Another object of the present invention is to provide a liquid crystal display device in which no alkaline port prevention film is formed on the substrate. A specific example of a liquid crystal display device will be described below with reference to FIGS. 1 and 2.

In the conventional example shown in FIG.
The substrate is coated with a silane coupling agent alignment film 2, and the ester-bonded liquid crystal 3 is sealed between the substrates. This results in very expensive glass that requires optical polishing, which significantly increases the cost of the liquid crystal display layer.

Another conventional embodiment shown in FIG. 2 uses No. 9 soda lime glass with an alkali elution amount of 0.4 to 0.5 as the substrate 11.
The alignment film 13 is coated with SiO by oblique evaporation or a silane coupling agent to encapsulate the ester-bonded liquid crystal 14. However, with this structure, there are many alkali ions contained in soda lime glass, which elute from the alignment film. Alkaline ion migration prevention films 1 and 2 are
An oxide such as i02 is formed by sputtering or the like.
This complicates the manufacturing process and significantly increases the manufacturing cost of the liquid crystal display device. The present invention eliminates the above drawbacks.

An embodiment of the present invention is shown in FIG. 3 and will be described. For the substrate 21, a glass classified between 9-shelf silicate glass and soda lime glass with an alkali elution amount of 0.03 to 0.3 is used, and the alignment treatment film 22 is coated with, for example, tetrafluoric acid, on the opposing surface of the substrate. Biphenyl is added to the liquid crystal composition 23 which is coated with an organic polymer of tyrene and sealed between the substrates, and the liquid crystal display device is a combination of the above. In this structure, glass with a high alkali content is used, but the alkali ions eluted from the glass are slightly suppressed from leaching into the liquid crystal due to the alkali elution prevention effect of the organic polymer used in the alignment treatment film. By using a liquid crystal composition to which biphenyl is added, which is less susceptible to the effects of alkali ions that disturb orientation, it is possible to achieve the same lifespan as conventional liquid crystal display devices without forming an alkali elution prevention film with oxides such as Si02. can be secured. In this way, the alkali elution amount is 0.02 to 3 of the shelf silicate glass.
If the amount is larger, the glass can have a practically usable surface flatness without the need for optical polishing, so the cost of the glass can be significantly reduced. Furthermore, since the amount of alkali elution is smaller than that of soda lime glass, which has an alkali elution amount of 0.4 or more, the influence of alkali ions can be prevented by combining the organic polymer alignment treatment film and the liquid crystal composition to which biphenyl is added. As a result, the glass cost can be greatly reduced, and the conventional formation of an alkali elution prevention film is no longer necessary, resulting in a very large rationalization effect. In the explanation of the present invention, the alkali elution amount 0.03 to 0.3 is 9, which has the greatest rationalizing effect.
A conventional alkaline bleed-out prevention film was formed using the glass of the present invention on a glass substrate of a conventional liquid crystal display device. However, even if conventional alignment treatment and liquid crystal are used, the rationalization effect is large, and by using the organic polymer of the present invention as an alignment treatment agent for this liquid crystal display device, it is possible to provide a liquid crystal display device with even more stable quality. . As explained above, in the liquid crystal display device of the present invention, a glass having an alkali elution amount of 0.03 to 0.3 is used for the glass substrate, biphenyl is added to the liquid crystal composition, and an alignment treatment agent is added to the liquid crystal composition. Since an organic polymer of tetrafluoroethylene is used, there is no need to take the trouble of attaching an alkali elution prevention film, which is expensive to process, and relatively inexpensive glass can be used.

It is ideal for mass production of liquid crystal display devices and has high industrial value.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a liquid crystal display device showing a conventional example. FIG. 2 is a sectional view of a liquid crystal display device showing a conventional example. FIG. 3 is a sectional view of a liquid crystal display device showing an embodiment of the present invention. ,
12, Z [compromised, '2

Claims (1)

[Claims] 1. A liquid crystal display device in which a liquid crystal composition is sandwiched between at least two opposing substrates each having an electrode pattern formed on the surface thereof, and an alignment treatment is performed on the inner surface of the substrates,
The amount of alkali elution from the substrate was measured by the JIS R3502 test method (hereinafter, the amount of alkali elution described in this specification was measured based on this standard) and was 0.03 to 0.
3 mg of glass, the liquid crystal composition is a liquid crystal composition to which biphenyl is added, and the treatment agent for the alignment treatment is tetrafluoroethylene. Device.