JPH04335615A - Liquid crystal display element - Google Patents

Abstract

PURPOSE:To enlarge the pretilt angle of sealed liquid crystals by forming an orienting film made of a polyimide obtained from a specified diamine compound and tetracarboxylic acid or its derivative on a substrate. CONSTITUTION:The orienting film made of the polyimide obtained from at least one of the diamine compounds represented by formula I and the tetracarboxylic acid or its derivative is formed on one the substrate. In formula I, R1 is H or optionally substituted straight or branched or alicyclic alkyl or optionally substituted aryl; X1 is a divalent bonding group; and X2 is a simple bond or a derivative bonding group. This liquid crystal display element is formed by laminating stripes or a lattice of transparent electrodes on the substrate, arranging these 2 substrates with the electrodes inside, and sealing in the liquid crystals between them.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device having a polyimide alignment film.

0002

[Prior Art] The basic structure of liquid crystal display elements conventionally used in displays for watches, computers, word processors, etc. is two transparent electrode substrates each having an alignment film on a transparent electrode. Usually, the structure is such that the liquid crystal is placed inside and the liquid crystal is sealed between them. The transparent electrode of such a liquid crystal display element is generally formed on a substrate in the form of a display pattern such as a stripe or a grid, and the alignment film is formed on the transparent electrode and the exposed substrate (other than the display pattern). It is provided by coating or vapor deposition on the entire surface. These two transparent electrode substrates are each arranged with the alignment film inside,
A liquid crystal display element is manufactured by sealing liquid crystal between them. Generally, the alignment film is provided because it is necessary to align, or align, liquid crystals in a certain direction, thereby aligning liquid crystal molecules.

The mainstream of such liquid crystal display elements is a twisted nematic (TN) mode display in which a nematic liquid crystal has a twisted structure. However, this TN type liquid crystal display element does not have a steep threshold value, so it is not suitable for large-capacity display using high multiplex drive (time division drive generally used for dot matrix). In addition, the response speed of TN type liquid crystal display elements is slow, and currently 20
It has the drawback of being limited to milliseconds, which is a major problem when used in television panels and the like that require high-speed response.

[0004]Recently, it has been developed to have the above-mentioned high-speed responsiveness that quickly responds to changes in the electric field, and also to change either the first optically stable state or the second optically stable state in response to the applied electric field. Ferroelectric liquid crystals are attracting attention because they have the property of retaining the same state when no voltage is applied, that is, have memory properties (also referred to as bistability). and,
A liquid crystal display element using this is being considered because it has a simple structure and can achieve high-speed response.

The operating principle of the TN mode utilizes the optical rotation of a liquid crystal cell with a twist angle of around 90 degrees, but if the SBE (super twist birefringence) mode using nematic liquid crystal is used, a steep threshold can be achieved. Since the value can be obtained, large-capacity display by high multiplex drive becomes possible. The SBE (super twisted birefringence) mode that provides such a steep threshold value utilizes the birefringence of a liquid crystal cell with a twist angle of 180 degrees or more using the liquid crystal described above. That is, it is necessary to twist the liquid crystal by 180 degrees or more between the upper and lower substrates in the alignment direction. For this purpose, the liquid crystal molecules are required to have a pretilt angle of 3 to 30 degrees at the substrate-electrode interface. Generally, such a pretilt angle is provided by an alignment film. On the other hand, if an alignment film giving such a pretilt angle is used, alignment defects in smectic liquid crystals such as the above-mentioned ferroelectric liquid crystals can be generally extremely reduced, and bistability can also be improved.

However, when an alignment film made of an organic material such as a polymer is formed on an electrode substrate and rubbed, which is used in the conventional TN mode, the pretilt angle of the aligned liquid crystal molecules is at most 2 degrees. It is not possible to obtain a large value. Furthermore, if an obliquely deposited film such as SiO is used as the alignment film, a large pretilt angle can be obtained, but forming the alignment film by adhesion has low mass productivity.
It cannot be said that it is advantageous in terms of manufacturing.

[0007] As a coating type alignment film material capable of obtaining a large pretilt angle, a polyamic acid composition comprising a component having a fluorine atom in at least one of a carboxylic acid anhydride and a diamine (Japanese Patent Application Laid-Open No. 127827/1982);
Also disclosed is an alignment treatment material for polyimide resin obtained from diamine, tetracarboxylic dianhydride, and specific monoamines (Japanese Patent Application Laid-Open No. 62-297819). In addition, as an alignment film for ferroelectric liquid crystals, a polyimide film ( JP-A-2-3
10524) and fluorine-containing polyimide (Japanese Patent Application Laid-open No. 3-25418).

However, when liquid crystals are aligned using the above-mentioned alignment film, there is a problem that a large pretilt angle cannot always be obtained, and that the pretilt angle tends to change depending on the conditions of post-treatment such as rubbing treatment.

[0009]

SUMMARY OF THE INVENTION An object of the present invention is to provide a liquid crystal display element having a polyimide alignment film exhibiting a large pretilt angle.

Another object of the present invention is to provide a liquid crystal display element having a polyimide alignment film suitable for multiplex driving.

[0011]

[Means for solving the problem] The above purpose is to
In a liquid crystal display element in which two transparent electrode substrates each having a laminated striped or lattice-like transparent electrode are arranged with each transparent electrode facing inside, and a liquid crystal is sealed between them, at least one of the transparent electrodes is placed on the transparent electrode. , the following general formula (I)
This can be achieved by a liquid crystal display element characterized in that an alignment film is formed of polyimide obtained from at least one diamine compound represented by the following and a tetracarboxylic acid or a derivative thereof. General formula (I)

[Chemical Formula 2] In the above formula, R1 represents a hydrogen atom, a substituted or unsubstituted alkyl group (linear, branched, or alicyclic), and a substituted or unsubstituted aromatic group, and X1 represents a divalent linking group. Representation, X2
represents a single bond or a divalent linking group.

The above general formula will be explained in detail below.

Specific examples of R1 are as follows:

00
14]

[Chemical formula 3] Unsubstituted alkyl groups such as;

[C4] Substituted alkyl groups such as;

[C5] Unsubstituted aromatic groups such as;

[C6] Substituted aromatic groups such as

Specific examples of divalent groups for X1 and X2 include -O-, -S-, -CO-, -SO2 -,
-SO-, -CONR2 -, -NR2 CO-, -S
O2 NR2 −, −NR2 SO2 −, −NR2
CONR3 -, -NR2 CONR3 CO-, -C
ONR2 CONR3 −, −COO−, −OOC
- and so on.

The above R2 and R3 have the same meaning as R1, but R2, R3 and R1 may be the same or different. R2 and R3 are particularly preferably a hydrogen atom or a straight-chain alkyl group having 1 or more and 14 or less carbon atoms.

X1 and X2 may be the same or different.

Preferred embodiments of the liquid crystal display element of the present invention are as follows.

In the general formula (I), R1 is a hydrogen atom,
Substituted or unsubstituted alkyl groups (linear, branched or alicyclic) having 1 to 14 carbon atoms, substituted or unsubstituted aromatic groups having 6 to 18 carbon atoms, particularly preferably 3 or more carbon atoms. They are a straight chain alkyl group having 8 or less carbon atoms and a straight chain or branched perfluoroalkyl group having 1 or more and 6 or less carbon atoms.

In the general formula (I), X1 is -CONR
2-, -SO2NR2- is preferred, and -CONR2- is particularly preferred.

In the general formula (I), X2 is a single bond, -
O-, -CO-, -NR2 CO-, -NR2 SO2
- is preferred, and a single bond, -O-, is particularly preferred.

The tetracarboxylic acid derivative used in the present invention is preferably a tetracarboxylic dianhydride, for example,

[0023]

[C7]

[0024]

[Chemical formula 8]

[0025]

[Chemical formula 9]

[0026]

[Chemical formula 10]

[0027]

[Chemical formula 11]

[0028]

[Chemical formula 12]

[0029]

[Chemical formula 13]

[0030]

[Chemical formula 14] etc. can be mentioned.

Specific examples of the general formula (I) of the present invention are shown below, but the present invention is not limited thereto.

[0032]

[Chemical formula 15]

[0033]

[Chemical formula 16]

[0034]

[Chemical formula 17]

[0035]

[Chemical formula 18]

[0036]

[Chemical formula 19]

[0037]

[C20]

[0038]

[C21]

[0039]

[C22]

[0040]

[C23]

[0041]

[C24]

[0042]

[C25]

[0043]

[C26]

[0044]

[C27]

[0045]

[C28]

[0046]

[C29]

[0047]

[C30]

[0048]

[Chemical formula 31]

[0049]

[C32]

[0050]

[Chemical formula 33]

[0051]

[C34]

[0052]

[C35]

[0053]

[C36]

[0054]

[C37]

[0055]

[C38]

[0056]

[C39]

[0057]

[C40]

[0058]

[C41]

[0059]

[C42]

[0060]

[C43]

[0061]

[C44]

[0062]

[C45]

[0063]

[C46]

[0064]

[C47]

[0065]

[C48]

[0066]

[C49]

[0067]

[C50]

[0068]

[C51]

[0069]

[C52]

[0070]

[C53]

[0071]

[C54]

[0072]

[C55]

[0073]

[C56]

[0074]

[C57]

[0075]

[C58]

[0076]

[C59]

[0077]

[C60]

A preferred structure of a liquid crystal display element obtained by the manufacturing method of the present invention will be explained. FIG. 1 shows a cross-sectional view of an example of the liquid crystal display element of the present invention.

[0079] Transparent electrodes 2a,
2b and the alignment films 3a and 3b are laminated in this order to constitute two transparent electrode substrates. If necessary, an insulating layer may be interposed between the transparent electrode and the alignment film. The two transparent electrode substrates are arranged so that the alignment films 3a and 3b face each other, and a ferroelectric liquid crystal 4 is sealed between them. Transparent electrodes 2a and 2b are formed in a striped display pattern on transparent substrates 1a and 1b, respectively.

As described above, the transparent electrodes 2a and 2b are formed into stripes, and the stripes are formed so that they are perpendicular to each other. This enables matrix display. Furthermore, only one of the transparent electrodes may be formed in a stripe shape. Further, it is not necessary to have both alignment films, and only one of them may be used.

[0081] The liquid crystal display element of the present invention has the above-mentioned alignment film 3a.
and 3b are formed from polyimide using the diamine compound of the above general formula (I) as a diamine component. By using this alignment film, liquid crystals, particularly ferroelectric liquid crystals, can be aligned at a large pretilt angle that can only be obtained with an alignment film formed by oblique evaporation of SiO.

The liquid crystal display element of the present invention is not limited to the one shown in FIG. 1, but can be made in any manner that is used for ordinary liquid crystal display elements, such as using spacers. In particular, it is preferable to use a spacer to ensure a gap between both alignment films (ie, the thickness of the liquid crystal layer). Glass fibers, glass beads, plastic beads, metal oxide particles such as alumina and silica are used as spacers. The particle size of the spacer varies depending on the liquid crystal used, the alignment film material, the setting of the gel gap, the particles used as the spacer, etc., but is 1.2μ.
m to 6 μm is common.

The liquid crystal display element of the present invention can be manufactured, for example, as follows.

Examples of the transparent substrate of the present invention include glass such as float glass with good smoothness, polyesters such as polyethylene terephthalate and polybutylene terephthalate, epoxy resins, phenol resins, polyimides, polycarbonates, polysulfones, polyethersulfones, Heat-resistant resins such as polyetherimide, acetyl cellulose, polyamino acid esters, and aromatic polyamides; vinyl polymers such as polystyrene, polyacrylic esters, polymethacrylic esters, polyacrylamide, polyethylene, and polypropylene; and fluorine-containing polymers such as polyvinylidene fluoride. Examples include plastic films formed from resins and modified products thereof.

A transparent electrode having a display pattern such as a stripe or a grid is formed on the substrate by a conventional method. As the transparent electrode, for example, indium oxide (I
n2O3), tin oxide (SnO2) and ITO
(indium tin oxide), etc.

Note that a color filter and a protective layer may be formed in this order on the surface of the substrate. The alignment film of the present invention is formed on the transparent electrode (and substrate), for example, in the following manner.

[0087] The polyimide alignment film of the present invention can be produced by various manufacturing methods, but is preferably produced by the above general formula (I).
It is obtained by dehydrating and condensing part or all of a polyamic acid obtained from at least one diamine compound represented by ) and a tetracarboxylic acid derivative.

Regarding the production of the above polyamic acid, the molar ratio of the diamine compound and the tetracarboxylic acid derivative may be any ratio, but preferably the ratio of diamine compound/tetracarboxylic acid derivative (number of moles/number of moles) is 0.50 to 2. .0
It is within the range of 0.83 to 1.2, particularly preferably 0.83 to 1.2.

The alignment film of the present invention can be prepared by dissolving a polyamic acid synthesized from a diamine compound represented by the general formula (I) and the above-mentioned tetracarboxylic acid derivative in a solvent to prepare a coating solution for forming an alignment film. This is applied onto a substrate, dried, and heat-treated to form a polyimide film partially or completely.

Synthesis Examples 1 to 3 of the diamine represented by the above general formula (I) are shown below.

Synthesis Example 1 Synthesis of B-12 8.06 g (0.05 mol) of 3-trifluoromethylaniline was dissolved in 50 ml of acetonitrile to 5 g of pyridine, and then 12.68 g of 3,5-dinitrobenzoyl chloride was added.
(0.055 mol) was gradually added and stirred at room temperature for 2 hours, and then added to 200 ml of water. After reduction in a system of .4 g, water 15 g, and isopropyl alcohol 100 ml, 5.6 g (0.019 mol) of diamine compound B-12 was obtained by recrystallizing from ethyl acetate to ethanol.

Synthesis Example 2 Synthesis of B-3 The procedure was repeated in the same manner as in Synthesis Example 1 except that N-methylaniline was used as the aniline compound, and 6.8 g (0.02
8 mol) was obtained.

Synthesis Example 3 Synthesis of B-11 Synthesis Example 1 except that n-octylaniline was used as the aniline compound.
In the same manner as above, add 10.85g of diamine compound B-11.
(0.032 mol) was obtained.

Synthesis Examples 4 to 7 of polyamic acid are shown below.

Synthesis Example 4 Polyamic acid; Synthesis of C-1 1.475 g (0.005 g) of diamine compound B-12
To a solution of 23.13 g of N-methyl-2-pyrrolidone (mol) was added 1.09 g of tetracarboxylic dianhydride (A-1) (0.
005 mol) was added and stirred at room temperature for 6 hours to obtain a 10 wt % polyamic acid; C-1 solution.

Synthesis Example 5 Polyamic acid: Synthesis of C-2 The same procedure as Synthesis Example 4 was carried out except that B-3 was used as the diamine compound.

Synthesis Example 6 Synthesis of Polyamic Acid: C-3 The same procedure as Synthesis Example 4 was carried out except that B-11 was used as the diamine compound.

Synthesis Example 7 Polyamic acids C-4 to C-20 were obtained according to Synthesis Examples 4 to 6. This is shown in Table 1. Table 1
Synthesis of polyamic acid Polyamic acid Diamine Acid anhydride Diamine/acid anhydride (molar ratio) C-4 B-5
A-1 1/1
C-5 B-8 A-1
1/1.1
C-6 B-10 A-1
1.1/1 C-7
B-14 A-1
1/1 C-8 B
-15 A-1
1/1 C-9 B-16
A-1 1.2/1
C-10 B-18 A-1
1/1 C-11
B-22 A-1
1/1.15 C-12
B-24 A-1
1/1 C-13 B-28
A-2 1/
1 C-14 B-29 A-
3 1/1 C
-15 B-31 A-4
1/1 C-16
B-35 A-5
1/1 C-17 B-3
9 A-6 1
/1 C-18 B-41 A
-7 1/1
C-19 B-43 A-8
1/1 C-20
a. B-8 b. B-22 A-1
(a/b=0.5/0.5)/1
C-21 B-16 c. A-1 d
．． A-2 1/(c/d=0.5/0.
5) C-22 a. B-8 b. B-22
c. A-1 d. A-2 (a/b=0.5
/0.5)/(c/d=0.5/0.5)

0099
The coating liquid for forming an alignment film is prepared by adding the polyamic acid solution obtained above or the polyamic acid obtained by reprecipitation, etc. to pyridine, N-methyl-2-pyrrolidone, dioxane, THF,
Solutions can be prepared in suitable solvents such as glycol derivatives. In addition to the above-mentioned components, other polymers, organic metals, etc. may be added to this coating liquid for the purpose of increasing adhesion to the substrate or adjusting the viscosity of the coating liquid.

[0100] A coating solution for forming an alignment film is applied onto the transparent electrode and the exposed substrate using a spin coater or the like, and the coating solution is applied at room temperature to 150°C under normal pressure or reduced pressure for 1 to 120 minutes (preferably 80 to 120°C). 10 to 80 minutes). Next, the coating film is heated at 150 to 300°C under normal pressure or reduced pressure.
．． Heat treatment is performed for 5 to 3 hours. Heating is done after 150
Heating at ~300°C for 0.5 to 3 hours is sufficient. This forms a polyimide alignment film.

The thickness of the resulting alignment film varies depending on the liquid crystal used and the type of alignment film, but is 10 to 800 nm, preferably 20 to 100 nm.

The alignment film provided on the transparent electrode substrate (and protective layer) is preferably rubbed with synthetic fibers such as nylon, polyester, and polyacrylonitrile, and natural fibers such as cotton and wool.

The polyimide alignment film of the present invention thus formed allows liquid crystal to be aligned at a large pretilt angle. This polyimide alignment film is characterized in that a diamine compound represented by the above general formula (I) is used as the diamine component of the polyimide.

[0104] A transparent substrate manufactured as described above,
Two transparent electrode substrates consisting of a transparent electrode and an alignment film are placed facing each other with a gap between them, with each alignment film facing inside, to form a cell. The size of this gap, ie, the cell gap, is preferably about 0.5 μm to 6 μm.

Next, the following liquid crystal (preferably ferroelectric liquid crystal) is injected into this cell, sealed, and then slowly cooled to produce a liquid crystal display element.

The liquid crystal used in the present invention is preferably a liquid crystal that can be used in the SBE mode or a ferroelectric liquid crystal, and a ferroelectric liquid crystal is particularly preferable.

Liquid crystals having ferroelectricity are specifically chiral smectic C phase (SmC*), H phase (SmH*
), I phase (SmI*), J phase (SmJ*), K phase (SmK*), G phase (SmG*) or F phase (Sm
F*). For example, "High-speed liquid crystal technology" (published by CMC) p. All known ferroelectric liquid crystals, such as those described in 127-161, can be used in the present invention.

[0108] Specific liquid crystal compositions include CS-1018, CS-1023, and CS- manufactured by Chisso Corporation.
1025, CS-1026, DO manufactured by Roddick Co., Ltd.
F0004, DOF0006, DOF0008, ZLI-4237-000, ZLI-4237- manufactured by Merck & Co.
100, ZLI-4654-100, ZLI-2293
etc. can be mentioned. There is no problem in adding dichroic dyes, viscosity reducers, etc. which are soluble in the liquid crystal to these liquid crystals.

[0109] The liquid crystal display element thus obtained is as follows:
Enclosed liquid crystal can be aligned at a large pretilt angle. The pretilt angle of the liquid crystal is preferably 3 degrees to 90 degrees, particularly preferably 5 degrees to 40 degrees.

[0110] The liquid crystal display element manufactured as described above may be provided with polarizing plates on both substrates of the cell depending on the purpose of use. An insulating layer, a color filter, a protective layer, etc. may be provided between the transparent electrode and the alignment film. Furthermore, the liquid crystal display element of the present invention can be provided with structures provided in conventional liquid crystal display elements, such as a reflection plate and a retardation plate, depending on the purpose of use.

[0111]

EXAMPLES Next, examples of the present invention will be described. However, the present invention is not limited to this example.

Example 1 Transparent electrodes of indium-tin oxide (ITO) were formed in stripes (electrode width: 100 μm, gap between electrodes: 15 μm) on two 1.1 mm thick glass substrates. .

[0113] On these two glass substrates with transparent electrodes,
An insulating layer with a thickness of 100 nm was formed by vapor depositing SiO.

A coating solution prepared by dissolving 3 parts by weight of C-1 polyamic acid and 97 parts by weight N,N-dimethylacetamide was applied onto the above insulating layer using a spinner.

[0115] The conditions for the spinner are a rotation speed of 2500 r. p
．． m. , the time was 30 seconds. After coating, it was dried at 280° C. for 1 hour to form a polyimide alignment film.

[0116] Both surfaces of this coating film were rubbed with a nylon napkin, and two glass plates were placed with each rubbed surface facing inward so that the rubbing directions were antiparallel and the electrode patterns were orthogonal. They were overlapped with a 3 μm spacer interposed therebetween to create a cell with a cell gap of 3 μm. One Merck liquid crystal ZLI-2293 was installed in this cell.
The mixture was injected at 00°C and slowly cooled to room temperature at a rate of about 2°C/min.

[0117] The pretilt angle of the obtained liquid crystal display element was measured by the crystal rotation method using a polarizing microscope manufactured by Nikon Corporation, and it was found to be 18°.

Example 2 A liquid crystal display element was manufactured in the same manner as in Example 1 except that C-2 polyamic acid was used as the polyamic acid.

The pretilt angle of the obtained liquid crystal display element was measured in the same manner as in Example 1, and was found to be 15°.

Example 3 A liquid crystal display element was manufactured in the same manner as in Example 1 except that C-3 polyamic acid was used as the polyamic acid.

[0121] The pretilt angle of the obtained liquid crystal display element was measured in the same manner as in Example 1, and it was found to be 22°.

Example 4 In Example 1, during the rubbing treatment with the nylon raised cloth, the direction of the rubbing was changed from antiparallel to the same direction with each rubbing surface facing inside, and the spacers were
Changed from μm to 2 μm, and changed the liquid crystal to Merck's ZL.
Ferroelectric liquid crystal CS- made by Chisso Corporation from I-2293
A liquid crystal display element was manufactured in the same manner as in Example 1 except that 1023 was used.

When the alignment state of the obtained liquid crystal display element was observed, it was found that a good alignment state with no zigzag defects was obtained. Furthermore, when the liquid crystal display element was subjected to multiplex driving, good contrast was obtained.

Example 5 In Example 4, the liquid crystal was a ferroelectric liquid crystal CS-1023.
The liquid crystal compositions shown in Table 2 below [phase transition temperature (°C) C
*58.0A83.4N*89.3Iso] A liquid crystal display element was manufactured in the same manner as in Example 4 except that the liquid crystal display element was changed to *58.0A83.4N*89.3Iso]. Table 2 Liquid crystal composition compounds

Composition ratio (wt%) 5-heptyl-2-(4-octyloxyphenyl)
11pyrimidine 5-nonyl-2-(4-octyloxyphenyl)
11pyrimidine 5-heptyl-2-(4-nonyloxyphenyl)
11 Pyrimidine 5-octyl-2-(4-octyloxyphenyl) 22 Pyrimidine 5-hexyl-2-(4-pentylbiphenyl-
4'-) 8pyrimidine 5-heptyl-2-(4-pentylbiphenylyl-
4'-) 8pyrimidine 5-octyl-2-(4-heptylbiphenylyl-
4'-) 8pyrimidine 5-nonyloxy-2-(4-heptylphenyl)
Pyrimidine 15 5-octyl-2-[4-((
2S)-2-Fluoro 5octyloxy)phenyl]pyrimidine 5-((2S)
-2-methylbutyl)-2-(4-heptyl
1biphenylyl-4'-)pyrimidine

When the alignment state of the obtained liquid crystal display element was observed, it was found that a good alignment state with no zigzag defects was obtained. Furthermore, when the liquid crystal display element was subjected to multiplex driving, good contrast was obtained.

Examples 6 to 24 In Example 4, C shown in Table 1 was used as the polyamic acid.
A liquid crystal display element was manufactured in the same manner as in Example 4 except that polyamic acids of -4 to C-22 were used.

[0127] When the alignment state of all the obtained liquid crystal display elements was observed, a good alignment state with no zigzag defects was obtained. Furthermore, when the above liquid crystal display elements were subjected to multiplex driving, good contrast was obtained in all cases.

[0128]

Effects of the Invention As shown in the above examples, the liquid crystal display element of the present invention includes a diamine compound of the present invention represented by the above general formula (I) in the alignment film for aligning the encapsulated liquid crystal. By using polyimide obtained by using at least one type of amine component as an amine component, it is possible to align liquid crystals at a large pretilt angle that can only be obtained with an alignment film formed by oblique evaporation of SiO, and there are almost no alignment defects. In addition, improved bistability can be obtained. Furthermore, since the alignment film of the present invention can be formed by coating, it is advantageous in manufacturing.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view schematically showing a configuration example of a liquid crystal display element of the present invention.

[Explanation of symbols]

1a, 1b: Transparent substrate 2a, 2b: transparent electrode 3a, 3b: alignment film 4: Liquid crystal

Claims (1)

[Claims] Claim 1: An alignment film made of polyimide obtained from at least one diamine compound represented by the following general formula (I) and a tetracarboxylic acid or a derivative thereof is formed on at least one of the substrates. Characteristic liquid crystal display element. General formula (I) [Formula 1] In the above formula, R1 represents a hydrogen atom, a substituted or unsubstituted alkyl group (linear, branched, or alicyclic), and a substituted or unsubstituted aromatic group, and X1 represents 2 represents a valent linking group, X2
represents a single bond or a divalent linking group.