JPS6287939A - Liquid crystal display device - Google Patents

Abstract

PURPOSE:To improve the contrast and visual characteristic of the titled display device by forming a polyimide polymer film obtained by dehydrating and cyclizing a specified polyamide acid on a substrate and an electrode. CONSTITUTION:The electrode is provided on the side facing a liq. crystal on the liq. crystal-contg. substrate. The film of the polyimide polymer, obtained by dehydrating and cyclizing a polyamide acid obtained by the reaction of a carboxylic anhydride and a diamine in which a fluorine atom is incorporated into at least one of the carboxylic anhydride and the diamine, is formed on the substrate and the electrode. The polyamide acid is synthesized by the reaction of the carboxylic anhydride and the diamine, and the reaction is preferably conducted in the absence of water at 50 deg.C or lower. The molar ratio of the carboxylic anhydride to the diamine in the reaction is preferably adjusted to 1, and the reaction is carried out in the presence of a solvent such as dimethylacetamide. Consequently, the liq. crystal display device having excellent contrast and visual characteristic can be obtained.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to a liquid crystal display device.

(Prior art) Super twisted birefringence effect (5upper twisted birefringence effect)
effect)
(T, J, 5chefferand J
, Nehring, Appl, phys, Le
A liquid crystal display device using FF, 1021 (1984)) has extremely superior contrast and visual characteristics compared to a conventional TN type device.

Since the alignment control film used for this purpose needs to have a high pretilt angle, an inorganic obliquely vapor deposited film such as silicon oxide or the like has been mainly used.

(Problems to be Solved by the Invention) However, the inorganic obliquely deposited film has selectivity to liquid crystals, and it is difficult to achieve good alignment of all liquid crystal compositions.

In addition, high-temperature heating during one assembly causes uneven orientation, lowers yield, and reduces productivity, and the contrast and visual characteristics required for an alignment control film cannot be satisfied.

The present invention provides a liquid crystal display device that eliminates this drawback.

(Means for Solving the Problems) The present invention provides a lateral pressure electrode facing the liquid crystal on a liquid crystal holding substrate, and on the substrate and the electrode, at least one of a carboxylic acid anhydride and a diamine is used as a component having a fluorine atom. The present invention relates to a liquid crystal display device in which a polyimide polymer coating is formed by dehydrating and enclosing a polyamic acid obtained by reacting a carboxylic acid anhydride and a diamine.

Polyamic acid, which is a precursor of polyimide used in the present invention, is synthesized by a reaction between a carboxylic acid anhydride and a diamine. These reactions are carried out under anhydrous conditions, preferably 5
It is carried out at a temperature of 0°C or lower.

What is the reaction rate of carboxylic acid anhydride and diamine?

It is preferable that the molar ratio of both is equimolar. This reaction is carried out in the presence of a solvent such as dimethylacetamide, dimethylformamide, dimethylsulfoxide or N-methyl-2-pyrrolidone.

In the present invention, a carboxylic acid anhydride and a diamine are reacted by using at least one of the carboxylic acid anhydride and the diamine as a component having a fluorine atom.

Examples of fluorine-containing carboxylic acid anhydrides include 2, for example, 4
2-bis(4-(3,4-dicarboxyphenoxy)phenyl)hexafluoropropane.

2.2-His(3,4-dicarboxyphenyl)hexafluoropropane, bis(,1-dicarboxyphenyl)hexafluoropropane, 4.4'-bis(4-(3
,4-dicarboxyphenoxinephenyl]hexafluoropropane, (trifluoromethyl)pyromellitic acid,
Bis(trifluoromethyl)pyromellitic acid, 5.5'-
Bis(trifluoromethyl)-a, 3:4.4'-tetracarboxybiphenyl, Su2:5゜5'-tetrakis(trifluoromethyl)-3,3:4゜4'-tetracarboxybiphenyl, 5. 5'-bis(trifluoromethyl)-3,t4.4'-tetracarboxydiphenyl ether, 5゜5'-bis(trifluoromethyl>-
at+, 4'-tetracarboxybenzophenone, bis(()lifluoromethyl)dicarboxyphenoxy]benzene, bis[(trifluoromethyl)dicarboxyphenoxine phenyl, bis[(trifluoromethyl)dicarboxyphenoxy](trifluoro methyl)benzene, bis[(trifluoromethyl)dicarboxyphenoxy]bis(trifluoromethyl)biphenyl, bis[
()lifluoromethyl)dicarboxyphenoxy]diphenyl ether, bis(dicarboxyphenoxy)(trifluoromethyl)benzene, bis(dicarboxyphenoxy)bis() IJfluoromethyl)benzene, bis(dicarboxyphenoxy)tetrakis(trifluoro methyl)benzene, bis(dicarboxyphenoxy)
Bis(trifluoromethyl)biphenyl, bis(dicarboxyphenoxy)tetrakis(trifluoromethyl)
biphenyl, 2.2-bis[4-(2,3-dicarboxybenzoyloxy)phenyl] + t-fluoropropane, 2.2-bis[4-(3,4-dicarboxybenzoyloxy)-3-bromophenyl ] Hexafluoropropane, 2.2-bis(4-(a4-dicarboxybenzoyloxy)-3,5-dibromophenyl) Hexafluoropropane, 2.2-bis(4-(3,4-dicarboxybenzoyloxy)-3,5-dibromophenyl) pensoyloxy)-3,5-dimethylphenyl]hexafluoropropane, 2,2-bis(4
-(3,4-dicarboxybenzoyloxy)phenyl]octafluorobutane, 2.2-bis[4-(2-trifluoromethyl-3,4-dicarboxybenzoyloxy)phenyl]hexafluoropropane, 1. 3-bis(4-(3,4-dicarboxybenzoyloxyphphenyl)hexafluoropropane, 1,5-bis[4-
(3,4-dicarboxybenzoyloxy)phenyl]
Decafluoropentane, 1,6-bis(:4-(3,4
-dicarboxybenzoyloxy)phenyl]dodecafluorohexane, 1,7-pis I: 4-(3,4-dicarboxybenzoyloxy)phenyl]tetradecafluorohebutane, l,5-bis(4-(3, 4-dicarboxybenzoyloxy)-&5-dibromophenyl]
Decafluoropentane, 1,5-bis(4-(3,4-
dicarboxybenzoyloxy)-3,5-bistrifluoromethylphenyl]decafluoropentane, 1.5
-bis(4-(2-trifluoromethyl-3,5-dicarboxybenzoyloxy)phenyl]tecafluoropentane, 2,2-bis[4-(3,4-dicarboxyphenoxy)phenyl]hexafluoropropane , Su2-
Bis[4-(Z3-dicarboxyphenoxy)phenyl]hexafluoropropane, 42-bis(4-(3,4
-dicarboxyphenoxy)-3-bromophenyl]hexafluoroglopane, 42-bis[:4-(3,4-
dicarboxyphenoxy)-3,5-dibromophenyl]hexafluoropropane, 2,2-bis(4-(3,
4-dicarboxyphenoxy)-3,5-dimethylphenyl]hexafluoropropane.

λ2-bis[4-(3,4-dicarboxyphenoxy)
phenyl]octafluorobutane, 2,2-bis(4-
(3,4-dicarboxy-2-trifluoromethylphenoxy)phenyl]hexafluoropropane, 1.3-
Bis(4-(3,4-dicarboxyphenoxy)phenyl)hexafluoropropa7, 1,5-His(4-(
3,4-dicarboxyphenoxy)phenyl]tecafluoropentane, 1,6-bis(4-(3,4-dicarboxyphenoxy)phenyl)dodecafluorohexane,
1.7-bis(:4-(3,4-dicarboxyphenoxy)phenylcotetradecafluorohebutane, 1.5-
BisC4-(3,4-dicarboxyphenoxy)-3
,5-dibromophenyl]tecafluorobentane, 1゜5-bis(4-(3,4-dicarboxyphenoxyphenoxy)-3
, 5-bistrifluoromethylphenyl]tecafluoropentane, 1,5-bis[4-(3,4-dicarboxy-2-trifluoromethylphenoxyphenyl]decafluoropentane), etc. are used.

In addition, examples of diamines containing fluorine include 1 and 2.
2-bis(4-(4-aminophenoxy)phenyl]hexafluoropropane, 2.2-bis1:4-<3-aminophenoxy)phenyl]hexafluoropropane,
2-bis[4-(2-aminophenoxy)phenyl]
Hexafluoropropane, 2-bis(4-(2-aminophenoxy)-3,5-dimethylphenyl)hexafluoropropane, p-bis(4-amino-2-trifluoromethylphenoxy)benzene, 4.4 '-bis(4
-amino-2-trifluoromethylphenoxy)biphenyl, 4.4'-bis(4-amino-3-trifluoromethylphenoxy)biphenyl, 4.4'-bis(4-
Amino-2-trifluoromethylphenoxy)diphenylsulfone, 4,4'-bis(3-7minor-5-trifluoromethylphenoxy)diphenylsulfone, 2
．． 2-bis[4-(4-amino-2-trifluoromethylphenoxy)phenyl]hexafluoropropane, 4
．． 4'-bis[4-aminophenoxy)phenyl]hexafluoropropane and the like are used.

Examples of the carboxylic anhydride include pyromellitic anhydride; , (,6,7-naphthalenetetracarboxylic anhydride, 3.3:4.4'-diphenyltetracarboxylic anhydride, x, z, s, 6-naphthalenetetracarboxylic anhydride, 2.2:3 .a'-diphenyltetracarboxylic anhydride, thiophene-2,3,4,5-tetracarboxylic anhydride, 2,2-bis(3,4-biscarboxyphenyl)propane anhydride, 3,4-di Carboxyphenylsulfone anhydride, perylene-3,4,910-
Tetracarboxylic anhydride, bis(3,4-dicarboxyphenyl)ether m hydrate, 3,3. '4.4'-
Benzophenone tetracarboxylic anhydride and the like are used.

In addition, examples of diamines include 2m-phenidiene diamine, p-phenyldiamine, 1m-xylene diamine, p-xylene diamine, 4,4'-diaminodiphenyl ether, 4,4'-diaminodiphenylmethane, λ
3'-dimethyl-4.4'-diaminodiphenylmethane, a,,5s,s'-tetramethyl-4,4'-diaminodiphenylmethane, 2.2'-bis(4-aminophenyl)propane, 4.4'- methylene dianiline, benzidine, 4,4'-diaminodiphenylsulfy)',
4.4'-diaminodiphenylsulfone, 1.5-
Diaminonaphthalene, 3,3'-dimethylbenzidine,
43'-dimethoxybenzidine and the like are used.

fluorine-containing carboxylic acid anhydride, carboxylic acid anhydride,
Two or more types of fluorine-containing diamines and diamines may be used in combination.

In addition, for the purpose of improving adhesion to glass substrates, metals, etc., the two reaction components are expressed by the general formula (where 几 is a divalent hydrocarbon group, R11R2, R3, and R4 are monovalent hydrocarbon groups, and n is a monovalent hydrocarbon group. It is an integer greater than or equal to 1.

) There is nothing wrong with using diaminosiloxanes shown in the formula below.

The above polyamic acid can be coated on the liquid crystal sandwiching substrate and electrodes using dimethylformamide, dimethylacetamide, dimethylsulfoxide, N-methyl-
As a 0.01 to 40% by weight solution of 2-pyrrolidone, etc.
This can be done by dip method, spinner method, spray method, printing method,
This is done by coating the substrate and electrodes using a brush coating method or the like.

Zoo°C~400℃ after coating, preferably 250℃~3
A polyimide film is obtained by heat-treating at 50° C. to dehydrate and ring-close the polyamic acid. This film is subjected to a rubbing treatment to form a liquid crystal alignment film. The tilt angle between the liquid crystal alignment film and the liquid crystal was 2 to 3 degrees with conventional polymer polyimide coatings, but when the polymer coating of the present invention was used as the liquid crystal alignment film, the tilt angle was up to about 2O4. Therefore, the polymer film of the present invention is particularly suitable for SBE type liquid crystal display devices.

(Example) This will be explained using an example.

In the example, the tilt angle is measured using a journal op.
Applied Physics (Jpn, J.

Appl, Phys, ) Vol. 19, p. 2013 (19
80) Performed by the method described in K.

Example I Using N-methyl-2-pyrrolidone as a solvent, 2°2-bis(:4-(4-aminophenoxy)phenyl)hex?
1.0 mol of fluoropropane and &2-bis(4-(3
,4-dicarboxyphenoxy)phenyl]hexafluoropropanihydride at 25°C for 5 hours and then at 80°C for 5 hours to obtain a 5 weight solution of polyamic acid in SN-methyl-2-pyrrolidone. A glass substrate (3c) on which indium oxide electrodes were formed using a spinner.
It was coated on an area of 2 m x 3 cm thick (2 m x 3 cm thick). 250 after application
The mixture was heated at ℃ for 1 hour to cause dehydration and ring closure, thereby forming a light yellow polyimide polymer film. Next, using a pair of substrates on which the film had been rubbed, a liquid crystal (ZLI-2293 (manufactured by Merck & Co., Ltd.) and a dextrorotating chiral agent CB15 (manufactured by BDH Company) were coated.
to 3.07 f/% to ZLI-2293 and left-handed chiral agent 8811 (manufactured by Merck & Co., Ltd.) to ZLI-2.
A liquid crystal display device (thickness: approximately 6.3 μm) was prepared by enclosing a 3.33% by weight mixture of 293 and 293% by weight. When the tilt angle was measured, it was 5.0°.

When voltage was applied to this device and the rise characteristics and contrast were observed, they were found to be extremely good.

Example 2 21.0 mol of 2,2-bis(4-(4-aminophenoxy)phenyl)hexafluoropropa and 3.3:4,4'-benzophenonetetracarvone using N-methyl-2-pyrrolidone as a solvent A liquid crystal display device exhibiting the same characteristics as in Example 1 using a 5% by weight N-methyl-2-pyrrolidone solution of polyamic acid obtained by condensing acid dianhydride at 25°C for 6 hours and then at 80°C for 6 hours. The tilt angle was measured and found to be 6.2°.

(Effects of the Invention) By using the polyimide-based polymer film of the present invention as an alignment control film, a liquid crystal display device with excellent contrast and visual characteristics can be obtained without reducing yield.

Claims (1)

[Claims] 1. An electrode is provided on the side facing the liquid crystal on the liquid crystal holding substrate, and on the substrate and the electrode, the carboxylic acid anhydride and the diamine are reacted with at least one of the carboxylic acid anhydride and the diamine as a component having a fluorine atom. A liquid crystal display device formed with a polyimide polymer film obtained by dehydrating and ring-closing polyamic acid obtained by