JPS583214B2 - LCD holding board - Google Patents

Description

[Detailed Description of the Invention] The present invention provides a means for improving the quality of the initial homogeneous alignment that can be used in a liquid crystal display device that requires liquid crystal molecules to be homogeneously aligned in an initial state (unexcited state). This invention relates to a liquid crystal supporting substrate.

Conventionally, as a means to improve the homogeneous alignment of liquid crystal molecules in the initial state, methods include forming an obliquely evaporated film of silicon oxide or the like on a substrate, forming a film of various surface treatment agents, organic polymers, etc. A method of rubbing the film is known.

However, each of these known methods has drawbacks as described below.

That is, the orientation ability of an obliquely deposited film such as silicon oxide differs depending on the type of liquid crystal substance, and there are liquid crystal substances that do not align at all.

This is a very serious problem when using a mixture of various liquid crystals to improve the temperature characteristics or electro-optical characteristics of the liquid crystal.

In addition, in the method of forming a film of various surface treatment agents, organic polymers, etc. and then rubbing the film, the heat resistance of the film is low, so the film deteriorates due to heating during device assembly and the orientation deteriorates. Most of them have the following drawbacks, and only heat-resistant organic polymer films such as polyimide have good heat resistance for orientation regulation.

However, these known polyimide-based polymer films have poor contact with the substrate surface, resulting in partial peeling of the coating during the rubbing process, resulting in poor alignment such as the formation of domains. There was a drawback that this occurred.

The present inventors conducted studies to eliminate the above-mentioned drawbacks of the prior art, and as a result, they arrived at the present invention.

In other words, the present invention allows the molecular axis of the liquid crystal to be aligned parallel to the substrate surface and in the characteristic direction of the substrate surface, regardless of the liquid crystal substance, and this liquid crystal alignment regulating force has excellent heat resistance and is resistant to rubbing. By improving the performance, it is possible to provide a liquid crystal display device that is stable over time, has a long life, and has high performance without imposing any restrictions on the assembly of liquid crystal display elements.

In the present invention, an electrode is provided on the side facing the liquid crystal on a liquid crystal supporting substrate, and a polyamic acid obtained by reacting a carboxylic acid anhydride, a diamine, and a diamino siloxane is dehydrated and ring-closed on the substrate and the electrode. The present invention relates to a liquid crystal supporting substrate formed with a polyimide silicon-based polymer film formed thereon.

Polyamic acid, which is a precursor of the polyimidosilane polymer used in the present invention, is synthesized by reaction of carboxylic acid anhydride, diamine, and diaminosiloxane.

These reactions are carried out under anhydrous conditions, preferably at temperatures of 50°C or less.

The reaction ratio of the carboxylic anhydride, diamine and diaminosiloxane is preferably such that the number of moles of the carboxylic anhydride is equal to the number of moles of the diamine and diaminosiloxane.

This reaction is carried out in the presence of a solvent such as dimethylformamide, dimethylacetamide, dimethylsulfoxide, N-methylpyrrolidone, or the like.

Examples of the carboxylic anhydride include pyromellitic anhydride, 2,3,6.7-naphthalenetetracarboxylic anhydride, 3,3',4,4'-diphenyltetracarboxylic anhydride, 1,2 , 5,6-naphthalenetetracarboxylic anhydride, 2,2',3,3'-diphenyltetracarboxylic anhydride, thiophene-2,3,4,5-tetracarboxylic anhydride, 2,2- Bis(3,4-dicarboxyphenyl)propane anhydride, 3,4-dicarboxyphenylsulfone anhydride, 10-tetracarboxylic anhydride, bis(3,4-dicarboxyphenyl)ether anhydride, 3,3',4,4'
-Penzophenonetetracarboxylic anhydride and the like are used.

Examples of the diamine include m-phenylenediamine,
p-phenylenediamine, m-xylenediamine, p-
Xylene diamine, 4,4'-diaminodiphenyl ether, 4,4'-diaminodiphenylmethane, 3.3'
-dimethyl-4,4'-diaminodiphenylmethane, 3
, 3',5,5'-tetramethyl-4,4'-diaminodiphenylmethane, 2,2'-bis(4-aminophenyl)propane-4,4'-methylene dianiline, benzidine, 4,4'-diamino diphenyl sulfide, 4,
4'-diaminodiphenyl sulfone, 1,5-diaminonaphthalene, 3,3'-dimethylbenzidine, 3,3'
-dimethoxybenzidine, 2,4-bis(β-amino-tert-butyl)toluene, bis(4-β-amino-tert-butylphenyl)ether, 1,4-bis(
2-methyl-4-aminobentyl)bennyl and the like are used.

The diaminosiloxane used in the present invention has, for example, the general formula (wherein R is a divalent hydrocarbon group, R1, R2, R3 and R4 are monovalent hydrocarbon groups, and n is an integer of 1 or more). The compounds shown are used, examples of which include compounds such as.

It is preferable to use aromatic compounds as the above-mentioned carboxylic acid anhydride, diamine, and diaminosiloxane from the viewpoint of heat resistance.

Diaminosiloxane is preferably used in an amount of 0.1 to 50 mol % based on the total amount of diamine and diaminosiloxane in terms of adhesiveness, heat resistance, stability, and properties.

The above-mentioned polyamic acid is applied onto the substrate and electrodes using a dipping method, a spinner coating method, etc. using a 0.01 to 40% weight solution of dimethylformamide, dimethylacetamide, dimethylsulfoxide, N-methylpyrrolidoxy, etc. It can be applied by methods such as method, spray method, printing method, brush coating method, etc.

100℃~400℃ after coating, preferably 250℃~35℃
A polyimide-silicon polymer film is obtained by heat treatment at 0° C. to dehydrate and ring-close the polyamic acid.

Hereinafter, the present invention will be specifically explained with reference to Examples and Comparative Examples.

Example 1 0.1 mole of 1,3-bis(aminopropyl)-tetramethyldisiloxane and 4,4' in N-methylpyrrolidone
-0.9 mol of diaminodiphenyl ether and 3,3'
,4,4'-benzophenonetetracarboxylic acid anhydride 1
．． A 15% by weight N-methylpyrrolidone solution of polyamic acid, which is a precursor of a polyimidosilane polymer obtained by condensing 0 mol of polyimide silane, was applied using a spinner to a glass substrate on which an indium oxide electrode was formed.

After coating, ring closure was performed by heating at 300° C. for 1 hour to form a polyimide silicon polymer film with a thickness of 1000 Å.

Thereafter, the coating was wrapped in a certain direction with gauze, but no peeling occurred in the polyimide silicone polymer coating.

Further, when a liquid crystal display cell was produced using a pair of substrates having the above-mentioned rubbed polyimide silicon polymer film, the alignment was very good.

Comparative Example I 1.0 mol of 4,4'-diaminodiphenyl ether and 1.0 mol of 3,3',4,4'-benzophenonetetracarboxylic acid anhydride are condensed in N-methylpyrrolidone. 15 of polyamic acid, which is the precursor of the obtained polyimide.
A polyimide film having a thickness of 1000 Å was formed by treating a wt % N-methylpyrrolidone solution in the same manner as in Doki Example 1.

Thereafter, when a rubbing process was performed in exactly the same manner as in Example 1, partial peeling occurred from the substrate.

Furthermore, when a liquid crystal display cell was produced using a pair of substrates having the above-mentioned rubbed polyimide film, poor alignment was observed in some parts.

As shown in the Examples and Comparative Examples, the polyimide-silicon polymer coating exhibits excellent adhesion to the substrate and can withstand all rubbing treatment conditions.

Furthermore, since the heat resistance of the liquid crystal alignment regulating force is extremely excellent, it is possible to provide a liquid crystal display device that is stable over time, has a long life, and has high characteristics without imposing restrictions on the assembly of liquid crystal elements.

Claims (1)

[Claims] 1 An electrode is provided on the side facing the liquid crystal on a liquid crystal supporting substrate, and a polyimide silicon type obtained by dehydrating and ring-closing a polyamic acid obtained by reacting a carboxylic acid anhydride, a diamine, and a diamino siloxane on the substrate and the electrode. A liquid crystal supporting substrate formed with a polymer film.