JPS61205924A - Liquid crystal display element - Google Patents

Abstract

PURPOSE:To obtain an excellent shelf life and good transparency without requiring thermal curing for a long period at a high temp. by using polyimide having a specific monomer unit for an oriented film. CONSTITUTION:The polyimide (PI) having the monomer unit expressed by the formula (R is two org. groups) is used for the liquid crystal oriented film formed on the surface of a substrate having a transparent conductive film 2. Such PI is easily soluble in an org. solvent, stable in a soln. state and does not cloud without a viscosity change even after long period preservation. The polyimide is then coated on the substrate 1 having the conducive film 2 and is dried for, for example, about 5-180min at 80-250 deg.C, by which the PI oriented film 3 is formed. The film 3 obtd. in such a manner withstands substantially the temp. in the stage of forming a seal and has the substantially stable heat resistance with lapse of time without the decrease in the liquid crystal orienta tion and without being colored in a liquid crystal operating temp. range. Such film is therefore used for the production of the element for which not only the glass substrate but also a plastic film having low heat resistance are used as the substrate.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a liquid crystal display element. In particular, the present invention relates to a liquid crystal display element using polyimide having a specific structure on the surface of a substrate on which an electrode pattern is formed.

(Prior technology) Conventionally, a nematic liquid crystal with positive dielectric anisotropy is formed into a sandwich structure using transparent electrodes coated with a liquid crystal alignment film, and the long axis of the liquid crystal molecules is twisted continuously by 90' between the upper and lower substrates. A display element made of a TN liquid crystal type is known. This alignment state of the liquid crystal can be achieved by rubbing the liquid crystal alignment film coated on the transparent electrode in one direction with paper or cloth, and by assembling the alignment films orthogonally to each other, the display function can be improved. can be expressed.

As a liquid crystal alignment film, polyimide itself has the function of aligning liquid crystal molecules in parallel, it can be applied as a solution so it can form a uniform coating on the substrate surface, the tilt angle with the liquid crystal molecules is small, and the contrast ratio is high. It has been widely used because it can display images, has a sharp dark value characteristic in which liquid crystal molecules begin to tilt during electrolytic response, and is suitable for multiplex drive.

Since polyimide is insoluble in organic solvents, conventional liquid crystal alignment films using polyimide require a solution of polyamic acid, which is a precursor of polyimide, obtained by, for example, reacting aromatic tetracarboxylic dianhydride with aromatic diamine. It was produced by applying it to a substrate at an appropriate concentration, followed by dehydration and ring closure at a temperature of 300 to 350°C or higher, and imidization.

(Problems to be Solved by the Invention) However, the above-mentioned polyamic acid has poor storage stability, such as precipitation of insoluble matter and decrease in viscosity, and thus needs to be stored at low temperatures.

In addition, when converting to polyimide, it is necessary to gradually raise the temperature to a high temperature and cure it for a long time, which is limited by the heat resistance of the material of the liquid crystal display element and other elements and parts incorporated in the element. It had drawbacks.

Furthermore, glass substrates have traditionally been used as substrates for liquid crystal display elements, but there is a trend towards lighter weight and thinner thickness, and due to mechanical properties and manufacturing constraints, glass substrates have a thickness of 0.
, 3 cranes is said to be the limit, so it has been considered to use a polymer film such as polyethylene terephthalate instead of a glass substrate. In such a substrate, polyamic acid type polyimide, which is imidized at high temperatures as described above, cannot be used because the polymer film lacks heat resistance. Furthermore, if it takes a long time to convert to polyimide, there is a big problem in terms of productivity. Furthermore, since these aromatic polyimides are colored, they also have the disadvantage that the display background is not clear.

An object of the present invention is to solve the conventional technical problems and provide a liquid crystal display element having a liquid crystal alignment film that has excellent storage stability, does not require long-term heat curing at high temperatures, and has excellent transparency. There is a particular thing.

(Means for Solving the Problems) The present invention provides a liquid crystal display element formed by forming a liquid crystal alignment film on the surface of a substrate having a transparent conductive film.
) is used as the liquid crystal alignment film.

The following margins (wherein R is a divalent aromatic group, an aliphatic group, an alicyclic group,
(means an organic group such as an organosiloxane group) The liquid crystal display element of the present invention is manufactured by applying an alignment treatment to the surface having the transparent conductive film 2 of a polarizing plate 6 provided with a transparent electrode (conductive film) 2, as shown in FIG. It has a liquid crystal alignment film 3 made of polyimide having a monomer unit of the general formula (1) given above. A glass substrate 1 is integrally provided inside the polarizing plate 6, and a liquid crystal composition 4 is sandwiched between the substrates, and the peripheral edge of the substrate is sealed with a sealant 5 to encapsulate the liquid crystal composition. be done.

A polyimide having a heptad unit of general formula (1) can be obtained by heating polyamic acid obtained by reacting tricarboxycyclopentyl acetic acid and a diamine. A method in which a polyamic acid obtained from carboxycyclopentyl acetic acid or its dianhydride and a diamine is subjected to an imidization reaction in the presence of an organic carboxylic acid anhydride in an organic solvent solution (JP-A-59-199720), or (2) 3゜5-
A method of reacting tricarboxycyclopentyl acetic dianhydride and diisocyanate in an organic solvent (Patent application 1983-
109239).

Here, 2.3.5-tricarboxycyclopentyl acetic acid (hereinafter referred to as rTCAJ) can be obtained by, for example, ozonolysis of dicyclopentadiene and oxidation with hydrogen peroxide [UK Patent No. 872355, J, Org, Chem. ,
, 28.2537 (1963)) or a method of oxidizing hydroxydicyclopentadiene obtained by hydrating dicyclopentadiene with nitric acid (West German Patent No. 107812)
0 specification) etc., and this T
2.3.5-Triforce by dehydrating CA
(i-ruboxycyclopentyl acetic dianhydride (hereinafter referred to as yCA-AHJ)). Y.

In addition, it may react with the TCA or TCA-AH.
The diisocyanate to be reacted with the diamine or TCA -AH has the general formula: H2N-1'1NH
2 or a compound represented by the general formula: 0CN-R-NCO (R is the same as in the general formula (I), and a divalent
- represents an organic group such as an aromatic group, an aliphatic group, an alicyclic group, an organosiloxane group, etc.) - (Preferable R in the general formula (1) is as follows:
For example,
(In r, Xl, X2, C-:0NH-, n represents O or 1), an aromatic group represented by (CH2)n-[-2~20), CH3(CI42)3C(CH2)3-CH3 It represents an aliphatic group or alicyclic group having 2 to 20 carbon atoms, an alicyclic or aromatic hydrocarbon group, and m is 1 to 10.
is an integer of 0].

Specific examples of the diamine include phenylenediamine, metaphenylenediamine, 4.4″-diaminodiphenylmethane, 4.41-diaminodiphenylethane,
benzidine, 4,4'-di; nodiphenyl sulfide,
4,4'-diami/nophenyl sulfone, 4,4'-diaminodiphenyl ether, ■, 5-diaminonaphculene, 3,3'-dimethyl-4,4'-diaminobifere, 3,4'-diaminobenz Alinide, 3°-diaminodiphenyl ether, 3.3'-7minobenzophenone, 3.4'-diaminoben1phenone, 4.4'-diaminobenzophenodiaminotetraphenylthiophene, methakyrndiamine, paraxylyne Diamine, enonediamine, ■, 3-propanediamine, teramethylenediamine, pentamethylenediamine, xamethylenediamine, heptamethylenediamine, octamethylenediamine, nonamethylenediamine, 4,4'-dimethylhebutamethylenediamine, 1. 4-diaminocyclohexane,
Examples include diaminoorganosiloxanes represented by tetrahydrodicyclopentadienylene diamine, hexahydro-4,7-methanoindanilene shimethylene diamine, tricycloC6,2,1,0)-landecylene dimethyldiamine, and the like. These organic diamines can be used alone or in combination of two or more.

As the isocyanate, a diisocyanate obtained by converting the diamine described above can be used. Specific examples include 2.4-1-lylene diisocyanate,
2.6-tolylene diisocyanate, p-phenylene diisocyanate, m-phenylene diisocyanate,
4,4'-diphenylmethane diisocyanate, 4.4
'-Diphenyl ether diisocyanate, 4.4'
-'; Phenylsulfone diisocyanate, 4,4'-
Aromatic diisocyanate compounds such as diphenyl sulfide diisocyanate, 1,5-naphthalene diisocyanate, 2,6-naphthalene diisocyanate, toridine isocyanate, 4,4'-biphenyl diisocyanate, p-xylylene diisocyanate, m-xylylene diisocyanate, isophorone diisocyanate Ne), 1
．． 3-bis(isocyanatomethyl)cyclohexane,
■.

4-bis(isocyanatomethyl)cyclohexane, 4
, 4'-dicyclohexylmethane diisocyanate, 4
．． Examples include alicyclic diisocyanate compounds such as 41-dicyclohexyl ether diisocyanate, aliphatic diisocyanate compounds such as butane diisocyanate, hexamethylene diisocyanate, octamethylene diisocyanate, lysine diisocyanate, and trimethylhexamethylene diisocyanate. These can be used alone or in combination.

Intrinsic viscosity (7i
nh=I! n (ri r e I) /c, c =
0.5 g/dI, 30° C. in dimethylformamide) is preferably 0.05 dl/g or more, particularly preferably 0.
05 to 5 di/g, and preferably has 50% by weight or more, particularly preferably 75% by weight or more of heptad units represented by the general formula (1).

TCA or TCA-AH that can be used in the present invention
Examples of the tetracarboxylic acid or its dianhydride that can be used in combination with pyromellitic acid or its dianhydride; 3. 3', 4. 4"-benzophenonetetracarboxylic acid or dianhydride thereof, 3.3', 4.4
'-Biphenylsulfonetetracarboxylic acid or its dianhydride, 1゜2.5.6-naphthalenetetracarboxylic acid or its dianhydride, 1.4.5.8-naphthalenetetracarboxylic acid or its dianhydride Things, 2,3°6.
7-naphthalenetetracarboxylic acid or its dianhydride; furantetracarboxylic acid or its dianhydride; 3.
3', 4,4°-Biphenyl ether tetracarboxylic acid or its dianhydride, 3.3°, 4,4'-dimethyldiphenylsilane tetracarboxylic acid or its dianhydride, 3,3°.

Aromatic tetracarboxylic acids such as 4.4'-tetraphenylsilane tetracarboxylic acid or its dianhydride, 3.3', 4.4'-perfluoroisopropylidene tetracarboxylic acid or its dianhydride, or this dianhydride,
cyclobutanetetracarboxylic acid or its dianhydride,
Cyclopentanetetracarboxylic acid or its dianhydride, 5-(2,5-dioxotetrahydrofuryl)-3-
Methyl-3-cyclohexenedicarboxylic acid or its dianhydride, bicyclo(2,2,2)-oct-7-ene-2,3,5,6-tetracarboxylic acid or its dianhydride, 3,5 .6-) dicarboxynorbornane-2-
Acetic acid or its dianhydride, alicyclic tetracarboxylic acid or its dianhydride such as tetrahydrofuran tetracarboxylic acid or its dianhydride, 1,2,3,4-butanetetracarboxylic acid or its dianhydride and aliphatic tetracarboxylic acids such as 2,2,6°6-heptanetetracarboxylic acid or its dianhydride or its dianhydride. These can be used alone or in combination.

The soluble polyimide used in the present invention is easily soluble in organic solvents and is very stable even in a solution state, and does not become cloudy or change in viscosity even during long-term storage.

Examples of organic solvents for such soluble polyimide include N-methyl-2-pyrrolidone, N,N-dimethylacetamide,
Examples include aprotic polar solvents such as N,N-dimethylformamide, dimethyl sulfoxide, γ-butyrolactone, and tetramethylurea, and phenolic solvents such as cresol, xylenol, and halogenated phenols, but among these, water absorption is low. In addition, a solvent system containing γ-butyrolactone as a main component is preferable because of the coating strength (no clouding) even when water is absorbed.

Other common organic solvents such as alcohols, phenols, ketones, esters, lactones, ethers,
Halogenated, hydrocarbons, hydrocarbons, e.g. evaporated methyl alcohol, ethyl alcohol, isopropyl alcohol, ethylene glycol, propylene glycol, 1,4
-Butanediol, triethylene glycol, ethylene glycol monomethyl ether, phenol, acetone, methyl ethyl ketone, methyl isobutyl series, cyclohexanone, methyl acetate, ethyl acetate, butyl acetate, diethyl oxalate, diethyl malonate, diethyl ether, ethylene glycol methyl ether, ethylene Glycol ethyl ether, ethylene glycol n-propyl ether, ethylene glycol 1SO-propyl ether,
Ethylene glycol n-butyl ether, ethylene glycol dimethyl ether, ethylene glycol ethyl ether acetate, diethylene glycol dimethyl ether, ethylene glycol n-butyl ether acetate, tetrahydrofuran, dichloromethane, 1,2-dichloroethane, 1,4-dichlorobutane, trichloroethane, chlorobenzene, 0- Dichlorobenzene, hexane, heptane, octane, benzene, toluene, xylene, etc. can also be mixed with the solvent in which the soluble polyimide is dissolved to an extent that the soluble polyimide is not precipitated.

The soluble polyimide solution used in the present invention is usually prepared to have a solid content concentration of 0.1 to 30% by weight, preferably 0.5 to 20% by weight.

The soluble polyimide composition solution prepared in this manner is applied onto a substrate 1 having a conductive film 2 by a roll coater method, a spinner method, a printing method, etc., as shown in FIG. 1, for example. Coating film 3 of soluble polyimide composition is formed by drying at 8° to 250°C for 5 to 180 minutes.
is formed.

The coating film thickness is 0.01-10μ, especially 0.01-10μ
1μ is preferred.

Furthermore, for the purpose of improving the adhesion to the substrate, a functional silane compound or a thicnate compound can be applied onto the substrate to improve the adhesion between the substrate and the soluble polyimide coating.

Specific examples of the functional silane compounds used include 3-
Aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 2-aminopropyltrimethoxysilane, 2-aminopropyltriethoxysilane, N
-(2-aminoethyl)-3-amino-propyltrimethoxysilane, N-(2-aminoethyl)-3-amino-propyltriethoxysilane, N-(2-aminoethyl)-3-amino-propylmethyl dimethoxysilane,
3-ureido-propyltrimethoxysilane, 3-ureido-propyltriethoxysilane, N-ethoxycarbonyl-3-aminopropyltrimethoxysilane, N
-Ethoxycarbonyl-3-amino-propyltriethoxyline, N-trimethoxysilylpropyl-triethylenetriamine, N-triethoxysilylpropyltriethylene 1 and amine, 10-trimethoxysilyl-1,4,Ll-riazabucan , 10-triethoxysilyl-1,4,7-)riazabucan, 9-trimethoxysilyl-3,6-diazatunyl acetate, 9-triethoxysilyl-3,6-diazatunyl acetate, N-
benzyl-3-amino-propyltrimethoxysilane,
N-benzyl-3-amino-propyltriethoxysilane, N-phenyl-3-amino-propyltrimethoxysilane, N-phenyl-3-amino-propyltriethoxysilane, N-bis(oxyethylene)-3-amino -propyltrimethoxysilane, N-bis(oxyethylene)-3-amino-propyltriethoxysilane, etc., and these functional silane compounds can also be used in combination.

R1)3, (RO)T i (OR2)3, (
Ro) Ti (OXR2): Monoalkyl titanate represented by 1, etc. (here, R is an alkyl group of 01 to C4, R1 is a vinyl group, an α-alkyl substituted vinyl group, or an alkyl group having 6 or more carbon atoms) group, aralkyl group, allyl group, or a derivative thereof, R2 represents an alkyl group having 6 or more carbon atoms, an aralkyl group, an allyl group, or a derivative thereof, and X represents diisostearoyl titanate,
Isopropyl trilauryl titanate, isopropyl trimyristyl titanate, isopropyl dimethacryloyl isostearoyl titanate, isopropyl tri(dodecylbenzenesulfonyl) titanate, isopropyl isostearoyl diacryloyl titanate, isopropyl tri(diisooctyl phosphate) titanate, isopropyl trimethacryloyl titanate, Isopropyl tri (dioctyl pyrophosphate) titanate, isopropyl triacroyl titanate, isopropyl tri (dioctyl phosphite) titanate, butyl 1-diisostearoyl titanate, ethyl tri isostearoyl titanate, etc.
O)nT i (OR”)-, -n, (where n is 2 or 3)
, R is an alkyl group, especially an alkyl group having 1 to 4 carbon atoms, and the ligand (R10-) other than the alkoxy group (RO-) is less likely to be hydrolyzed than the bond between the alkoxy group and titanium. R1 is a triethanolamine residue, an acyl group, an aroyl group, an acryloyl or methacryloyl group, an alkylbenzenesulfonyl group, an alkyl group having 6 or more carbon atoms, particularly preferably 10 or more carbon atoms, or a derivative thereof, and n is In the case of 2, these ligands (RIO-) can be the same or different from each other), for example bis(triethanolamine)diisopropyltitanate, bis(triethanolamine)dibutyltitanate, bis( triethanolamine)
Diethyl titanate, bis(triethanolamine) dimethyl titanate 1-, diisopropyl dilauryl titanate, diisopropyl lauryl myristyl titanate, diisopropyl distearoyl titanate, diisopropyl stearoyl methacryloyl titanate, diisopropyl diacryloyl titanate, diisopropyl didodecylbenzenesulfonyl titanate, diisopropyl titanate Isostearoyl-4-aminobenzoyl titanate, triisopropylacryloyl titanate, triethyl methacryloyl titanate, triisopropyl myristyl titanate, tributyldodecylbenzenesulfonyl titanate, triisopropylstearoyl titanate, triisopropylisostearoyl titanate, and the like.

It is of course possible to use two or more of these titanate compounds in combination.

The above-mentioned functional silane compound or titanate compound can also be used by mixing with the above-mentioned soluble polyimide.

Although the liquid crystal alignment film using the polyimide of the present invention has slightly lower heat resistance than conventional polyimide made from polyamic acid as a coating material, it can sufficiently withstand the temperature during sealing of liquid crystal display elements and has liquid crystal alignment properties. It does not cause coloring even in the practical operating temperature range of liquid crystals, and has heat resistance that is sufficiently stable over time.

The liquid crystal having positive dielectric anisotropy used in the present invention is not particularly limited, and there is no particular limitation as long as it forms a nematic liquid crystal. Specific examples of these include, for example, a Schiff base system represented by the following general formula (II) (Ill), an azo system represented by (TV), an azoxy system represented by <V>, and a benzoic system represented by (VT). Acid ester type, biphenyl type represented by (■), terphenyl type represented by (■), cyclohexylcarboxylic acid type represented by ([X), (
Phenylcyclohexane system represented by X), (XI)
Biphenylcyclohexane system represented by (XI), pyrimidine system represented by (X III), dioxane system represented by (X IV
), cyclohexylcyclohexane system, (XV)”if expressed, bicyclooctane system, Cn H
2Fk+(+X (XV)(X■
), and the cupane series represented by Here, H and m represent 1 to 1 group. These can be used alone or in combination. These blends provide properties such as a wide liquid crystal operating temperature range, chemical and optical stability, low viscosity, large dielectric anisotropy, moderate birefringence, balanced elastic modulus, and high molecular order. characteristics can be obtained.

As the substrate l used in the present invention, float glass or a flexible polyester film such as polyethylene terephthalate or polybutylene terephthalate can be used.

The transparent conductive film (electrode) 2 is NE made of SnO□.
SA film and ITO film made of In203-3n○2 can be used, and photo-etching is used for patterning these electrodes.
An etching method or a method using a mask in advance is used.

The polarizing plate 6 can be made of a cellulose acetate protective film sandwiching a polarizing film called an H film in which polyvinyl alcohol is stretched and oriented to absorb iodine, or it can be made of HH2 itself.

As the sealant 5 used in the present invention, for example, filler,
Epoxy resin compositions containing hardeners and aluminum oxide spheres as spacers can be used.

As the sealing agent for the liquid crystal substance, there are organic sealants and inorganic sealants, and either of them may be used, but organic sealants are particularly preferred because they can be operated at low temperatures.

As described above, a pair of electrode substrates provided with a liquid crystal alignment film, an electrode, a substrate polarizing plate, and a sealant are placed facing each other so that these liquid crystal alignment films are on the inside and their alignment processing directions cross each other. A liquid crystal display element of the invention is manufactured.

The liquid crystal display element of the present invention has excellent alignment properties and reliability, and can be effectively used in various devices by combining with a polarizer such as a linearly polarizing plate or a circularly polarizing plate or a reflecting plate. It is used in display devices such as electronic desktop calculators, wristwatches, table clocks, coefficient display boards, and liquid crystal televisions.

(Examples) Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples.

Example work 2, 3. Polyimide obtained from 5-1-licarboxycyclopentyl acetic dianhydride and 4,4'-diaminodiphenyl ether Qinh = 0.74d (1/g
) of 2 wt% γ-butyrolactone solution with pore size 0
．． The solution filtered through a 22 μm filter was subjected to spin coding using a spinner on a glass substrate on which a predetermined pattern of rTo transparent electrodes was formed. After coating, the substrate was dried at 200° C. for 30 minutes. The resulting coating film also had excellent transparency, and when the visible light transmittance of a film with a thickness of 1 μm and 119 μm was examined, as shown in FIG. 2, it showed a transmittance of 95% or more. Next, the coated surfaces of the pair of substrates were rubbed in one direction with a cloth for orientation treatment, and cells were assembled so that the rubbing directions were perpendicular.

Next, it was sealed with a sealant made of a mixture of epoxy resin, talc as a filler, acid anhydride as a hardening agent, and 10 μm aluminum oxide balls as a Spencer. Phenylcyclohexane-based liquid crystal is injected through the liquid crystal injection port, sealed, and then a polarizing plate is placed on both sides of the outside of the cell so that the polarization direction of the polarizing plate matches the rubbing direction of the liquid crystal alignment film applied to each substrate. The liquid crystal display element of the present invention was prepared by bonding the liquid crystal display element to the liquid crystal display element of the present invention.

The liquid crystal alignment state of the obtained liquid crystal display element was examined, and it was found to be in a good alignment state. Further, a high temperature environment test was performed at 80° C. for 200 hours, but there was no change in the display characteristics of the liquid crystal display element.

Example 2 Before applying the polyimide solution used in Example 1 to the substrate, the substrate was coated with 10-trimethoxysilyl-1°4.7-1-
Treated with Riazabucan. The other operations were the same as in Example 1.

The obtained liquid crystal was used in a display element with good liquid crystal orientation,
Even in a high temperature environment test at 80° C. for 200 hours, no deterioration in the display characteristics of the liquid crystal display element was observed.

Example 3 Instead of the silane coupling agent used in Example 2, 9-
A liquid crystal display element was produced in the same manner as in Example 1 except that trimethoxysilyl-3,6-diazatunyl acetate was used.

The liquid crystal alignment state of the obtained liquid crystal display element was good, and 8
Even in a high temperature environment test at 0° C. for 200 hours, no deterioration of the display characteristics of the liquid crystal display element was observed.

Example 4 Polyimide obtained from 2.3.5-tricarboxycyclopentyl acetic dianhydride and 4,4°-diaminodiphenylmethane (1'/i n h =0.77 djl'
/g) 2% by weight of γ-butyrolactone/N,N
-dimethylacetamide (=60/40 (weight ratio))
A liquid crystal display element was produced in the same manner as in Example 1 except that the solution was used.

In addition, the film thickness obtained by coating this polyimide is 0, 1 μm.
The visible light transmittance of the coating film of No. m was 98% or more, and the transparency was also excellent.

The liquid crystal alignment state of the obtained liquid crystal display element was good, and 8
Even in a high temperature environment test at 0° C. for 200 hours, no deterioration of the display characteristics of the liquid crystal display element was observed.

Example 5 2.3.5-tricarboxycyclopentyl acetic dianhydride and 4.4'-diaminodiphenyl ether/(3-aminopropyl)tetramethyldisiloxane = 90/10
(weight ratio) polyimide (N1nh-0,8
A liquid crystal display element was prepared in the same manner as in Example 1, except that a 2% by weight γ-butyrolactone solution (5 dJ/g) was used.

In addition, the film thickness obtained by coating 4 with this polyimide is 0.1
The visible light transmittance of the μm coating film was 98% or more, and the transparency was also excellent.

The liquid crystal alignment state of the obtained liquid crystal display element was good, and 8
Even in a high temperature environment test at 0° C. for 200 hours, no deterioration of the display characteristics of the liquid crystal display element was observed.

(Effects of the Invention) According to the present invention, by applying a specific polyimide solution on the substrate and/or the pattern of the transparent conductive film (electrode) and drying it, not only liquid crystal alignment ability but also heat resistance and A liquid crystal alignment film with excellent transparency can be formed. In addition, since the liquid crystal alignment film of the present invention does not require high temperature and long-term thermal curing, it is easy to manufacture liquid crystal display elements. It is also possible to manufacture display elements.

Further, the polyimide used in the present invention has a low refractive index of, for example, 1.5.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of a liquid crystal display device, and FIG. 2 is a diagram showing the wavelength dependence of the transmittance of the polyimide coating film used in the present invention. ■... Substrate, 2... Transparent conductive IJ (electrode), 3...
...Liquid crystal alignment film, 4...Liquid crystal, 5...Sealing agent, 6
···Polarizer. Agent Patent Attorney Takenaga Kawakita Figure 1 Figure 2 λ (nm) Procedural Amendment April 10, 1985

Claims (1)

[Claims] (1) In a liquid crystal display element formed by forming a liquid crystal alignment film on the surface of a substrate having a transparent conductive film, there are general formulas: ▲numerical formulas, chemical formulas, tables, etc.▼...(I) (in the formula, R is , meaning a divalent organic group) is used as the liquid crystal alignment film.