CN1140195A - Liquid crystal alignment agent and liquid crystal display - Google Patents

Abstract

A liquid crystal aligning agent comprising a polyamic acid containing an aliphatic and/or alicyclic hydrocarbon group and a polyimide containing an aliphatic and/or alicyclic hydrocarbon group ; and a liquid crystal display device using the liquid crystal aligning agent. This liquid crystal aligning agent produces a liquid crystal aligning film with good liquid crystal aligning properties, and wherein the pretilt angle can be changed by irradiation with small energy, and this aligning agent is suitable for a segmented alignment type liquid crystal display with a wide viewing angle.

Description

Liquid crystal alignment agent and liquid crystal display

The present invention relates to a kind of liquid crystal alignment agent that is used for the liquid crystal aligning agent of partition orientation type liquid crystal display, and the present invention relates to such a kind of liquid crystal alignment agent especially, when this liquid crystal alignment agent forms liquid crystal alignment film, its liquid crystal alignment performance is excellent, and by irradiation Exposure to the liquid crystal alignment film can change the pretilt angle of the liquid crystal.

There is known a liquid crystal display (hereinafter referred to as "TN-STN display") which has a sandwich structure in which two substrates composed of a transparent electrode and a liquid crystal alignment film formed of polyimide, etc. A liquid crystal with positive dielectric anisotropy is sandwiched between the two substrates, and there is a TN (twisted nematic) or STN (super twisted nematic) liquid crystal cell between the two substrates, in which the main axis of the liquid crystal molecules can be in Twist continuously in the range of 90 to 270°. However, the TN-STN display has a problem that, since the display is turned on and off by using the rise and fall of liquid crystal molecules with anisotropic refractive index, the viewing angle of the display is particularly narrow for halftone display.

In other words, for example, in the case of a normal white mode of a TN-STN display that displays white when no voltage is applied, its voltage-transmittance characteristic is as shown in L1 of FIG. ₁ when viewed from the front, and when The transmittance decreases as the applied voltage increases. However, when viewed from the diagonal at a certain angle in the direction normal to the rising direction of the liquid crystal, its voltage-transmittance characteristic is as shown in _L2 in Figure 1, and the characteristic curve has a transmittance that varies with the applied An area that increases with increasing voltage. Hue inversion occurs in this area so that the black and white of the image are reversed. In addition, when viewed along the diagonal at a certain angle from the opposite side of the normal viewing direction, its voltage-transmittance characteristics are shown in L ₃ in Figure 1, and the black-and-white contrast drops significantly. In order to solve this problem, it has been reported that in such a way, by combining two substrates coated with a liquid crystal alignment film exhibiting high and low pretilt angles and a segmented alignment type liquid crystal (SID '92 Digest, page 798), A region with a high pretilt angle and a region with a low pretilt angle are made to face each other between the upper substrate and the lower substrate.

When the upper (or lower) region and the lower (or upper) region respectively having a high pretilt angle and a low pretilt angle are combined together, the liquid crystal turns to the alignment direction of the region having a high pretilt angle. Utilizing this phenomenon, the alignment direction of the liquid crystal is reversed in the region where the upper substrate has a high pretilt angle and the region where the lower substrate has a low pretilt angle, to obtain a normal direction and an opposite direction within each pixel range. viewing angle. Thus, the viewing angle characteristic (L ₄ ) is uniform, so that an excellent display without black-and-white color inversion and sharp drop in contrast can be obtained when viewed from the front and back sides. Fig. 2 shows an example of the structure of such a liquid crystal display. Since the orientation direction can be arbitrarily determined by selecting an appropriate pretilt angle, the structure is not limited to this example. Fig. 3 shows an example of the structure of a conventional liquid crystal display for comparison.

As a method of forming liquid crystal aligning films having high and low pretilt angles on the same substrate, Fig. 4 shows a known method as an example.

First, a liquid crystal alignment film A is formed on a substrate. Another layer of liquid crystal alignment film B having a pretilt angle different from liquid crystal alignment film A is formed on film A (for example, the pretilt angle of film A is 7°, and the pretilt angle of film B is 1°). In addition, an alkali developing type positive resist is formed on the film B, and exposure and development are performed by a predetermined pattern to remove the exposed regions of the resist and the liquid crystal aligning agent.

Then, the unexposed area of the resist is removed to form a liquid crystal alignment film A area and a liquid crystal alignment film B area, ie, a low pretilt angle area and a high pretilt angle area in a pattern of exposed and unexposed areas.

There are some problems in the above method of forming patterns, such as very strict requirements on the liquid crystal alignment film, complex manufacturing process, and deterioration of the electrical properties of the liquid crystal display. Therefore, a method to replace this method has been proposed, that is, a method of controlling the pretilt angle by changing the liquid crystal alignment film caused by direct exposure of the liquid crystal alignment film formed on the substrate by irradiation (see EP613037A).

However, when a conventional liquid crystal aligning agent is used, exposure to radiation does not change the pretilt angle in some cases, and even when the pretilt angle is changed, a large amount of irradiation energy is required to obtain a desired difference in the pretilt angle. Therefore, conventional liquid crystal aligning agents cannot meet the needs of the above-mentioned applications.

It is therefore an object of the present invention to provide a liquid crystal aligning agent which is excellent in liquid crystal aligning properties when it forms a liquid crystal aligning film, and which causes Changes in the pretilt angle.

Other objects and advantages of the present invention will be apparent from the following description.

According to the present invention, these objects and advantages can be achieved by a liquid crystal aligning agent for a segmented alignment type liquid crystal display, which liquid crystal aligning agent comprises a polymer comprising at least one compound derived from the following structural formula (1) A structural unit selected from the group of the structural unit represented by (hereinafter referred to as "specific structural unit I") and the structural unit represented by the following structural formula (2) (hereinafter referred to as "specific structural unit II"), and used When the liquid crystal aligning agent forms a thin film after exposure to irradiation, the liquid crystal aligning agent has the ability to change the pretilt angle of the liquid crystal,

wherein R and ^R are tetravalent and divalent organic groups, respectively, and at least one of ^the organic groups is an aliphatic or cycloaliphatic hydrocarbon group, or is a group containing an aliphatic or cycloaliphatic hydrocarbon group,

wherein ^R3 and ^R4 are tetravalent and divalent organic groups, respectively, and at least one of the organic groups is an aliphatic or alicyclic hydrocarbon group, or a group containing an aliphatic or alicyclic hydrocarbon group.

Fig. 1 shows the voltage transmittance characteristic of a conventional TN-STN display;

Fig. 2 represents an example of the liquid crystal display structure that is formed with the liquid crystal aligning film with high and low pretilt angle on same substrate;

Fig. 3 represents another example of the liquid crystal display structure that one is formed with the liquid crystal aligning film of identical pretilt angle on identical substrate;

4 is a diagram for explaining a method for manufacturing a liquid crystal aligning film using two liquid crystal aligning agents exhibiting different pretilt angles to form high and low pretilt angles on the same substrate;

FIG. 5 is a diagram for explaining a method for manufacturing a segmented alignment type liquid crystal display using the liquid crystal aligning agent of the present invention;

Fig. 6 is a sectional view for measuring the liquid crystal display of pretilt angle;

Fig. 7 is a sectional view of a liquid crystal display used for measuring alignment characteristics; and

FIG. 8 is a diagram explaining the steps of forming a liquid crystal display using a liquid crystal alignment film in an embodiment of the present invention.

The polymer mainly comprising the specific structural unit I (hereinafter referred to as "specific polymer I") used in the present invention can be obtained by reacting tetracarboxylic dianhydride with diamine. A polymer mainly comprising specific structural unit II (hereinafter referred to as "specific polymer II") can be obtained by thermally or chemically aminating structural unit I of a polymer comprising equivalent specific structural unit I ). In the manufacture of specific polymer I, acid anhydrides and monoamine compounds can be added for the purpose of controlling the molecular weight of the polymer, improving the adaptability to the substrate or providing a pretilt angle. The thus-prepared finally modified Specific Polymer I and Specific Polymer II which is an aminated polymer of Specific Polymer I can be used as the liquid crystal aligning agent of the present invention without any problem. The aliphatic and/or alicyclic hydrocarbon groups contained in the specific polymer I and the specific polymer II may be contained in at least one of tetracarboxylic dianhydride and diamine. These groups are preferably contained in two or more components.

In the present invention, from the viewpoint of solubility in an organic solvent, the ratio of the specific structural unit I and/or the specific structural unit II as a polymer of the liquid crystal aligning agent is preferably 40 to 100 mol %, more preferably 60 mol %. to 100 mol%, most preferably 70 to 100 mol%.

Also in the present invention, from the viewpoint of liquid crystal alignment properties, after the following baking, the ratio of characteristic structural unit II to the polymer for forming a liquid crystal alignment film for a liquid crystal display is preferably 40 to 100 mol%, more preferably It is preferably 60 to 100 mol%, most preferably 70 to 100 mol%.

According to the present invention, specific polymer I is actually called polyamic acid and specific polymer II is actually called polyimide. Specific polymer I is generally represented by the following structural formula (A):

wherein R and ^R are tetravalent and divalent organic groups, respectively, and at least one of the organic groups is an aliphatic or alicyclic hydrocarbon group ^, or is a group containing an aliphatic or alicyclic hydrocarbon group, and n is the number of repeating units.

Specific polymer II is generally represented by the following structural formula (B):

wherein ^R3 and ^R4 are tetravalent and divalent organic groups, respectively, and at least one of the organic groups is an aliphatic or alicyclic hydrocarbon group, or a group containing an aliphatic or alicyclic hydrocarbon group, and n is the number of repeating units.

Specific polymer II sometimes contains specific structural unit I.

Illustrative examples of tetracarboxylic dianhydrides include aliphatic or cycloaliphatic tetracarboxylic dianhydrides, such as butane tetracarboxylic dianhydride, 1,2,3,4-cyclobutane tetracarboxylic dianhydride, 1, 2,3,4-cyclopentanetetracarboxylic dianhydride, 2,3,5-tricarboxycyclopentyl acetic anhydride, 3,5,6-tricarboxynorbornane-2-oxalic anhydride, 2, 3,4,5-tetrahydrofuran tetracarboxylic dianhydride, 1,2,3a,4,5,9b-hexahydro-5-(tetrahydro-2,5-dioxo-3-furyl)-benzo [1,2-c]-furan-1,3-dione, 5-(2,5-dioxotetrahydrofuryl methylene)-3-methyl-3-cyclohexane-1,2-dicarboxy acid dianhydride and bicyclo[2,2,2]-oct-7-ene-2,3,5,6-tetracarboxylic dianhydride; and aromatic tetracarboxylic dianhydride, such as pyromellitic dianhydride, 3,3',4,4'-diphenylsulfone tetracarboxylic dianhydride, 1,4,5,8-naphthalene tetracarboxylic dianhydride, 2,3,6,7-naphthalene tetracarboxylic dianhydride, 3,3',4,4'-Dimethyldiphenylsilane tetracarboxylic dianhydride, 1,2,3,4-furan tetracarboxylic dianhydride, 4,4'-bis(3,4-di Carboxyphenoxy) diphenyl sulfide dianhydride, 4,4'-bis(3,4-dicarboxyphenoxy)diphenylpropane dianhydride, 3,3',4,4'-perfluoroiso Propylenediphthalic dianhydride, bis(phthalic acid) phenylphosphine oxide dianhydride, p-phenylene-bis(triphenylphthalic acid) dianhydride, m-phenylene-bis (Triphenylphthalic acid) dianhydride, bis(triphenylphthalic acid)-4,4'-diphenyl ether dianhydride and bis(triphenylphthalic acid)-4,4'-diphenyl methane dianhydride. Among them, 1,2,3,4-cyclobutane tetracarboxylic dianhydride, 1,2,3,4-cyclopentane tetracarboxylic dianhydride, 2,3,5-tricarboxycyclopentylethyl Dianhydride, 1,3,3a,4,5,9b-hexahydro-5-(tetrahydro-2,5-dioxo-3-furyl)-naphtho[1,2-c]-furan- 1,3-diketone, 5-(2,5-dioxotetrahydrofurylmethylene)-3-methyl-3-cyclohexane-1,2-dicarboxylic dianhydride and bicyclo[2,2 , 2]-oct-7-ene-2,3,5,6-tetracarboxylic dianhydride. Particularly preferred are 1,2,3,4-cyclobutanetetracarboxylic dianhydride and 2,3,5-tricarboxycyclopentylethanedianhydride. They can be used alone or in combination of two or more.

Illustrative examples of diamine compounds include aromatic diamines such as 3,5-diaminobenzoic acid, 4,4'-diaminodiphenylethane, 4,4'-diaminodiphenylsulfide, 4 , 4'-diaminodiphenyl sulfone, 4,4'-diaminodiphenyl ethyl ether, 1,5-diaminonaphthalene, 3,3-dimethyl-4,4'-diaminodiphenyl, 4,4'-diaminobenzanilide, 3,4'-diaminodiphenyl ethyl ether, 3,3'-diaminobenzophenone, 3,4'-diaminobenzophenone, 4,4'-diaminophenone Aminophenone, 2,2-bis[4-(4-aminophenoxy)phenyl]propane, 2,2-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane, 2, 2-bis(4-aminophenyl)hexafluoropropane, 2,2-bis[4-(4-aminophenoxy)phenyl]sulfone, 1,4-bis(4-aminophenoxy)benzene, 1,3-bis(4-aminophenoxy)benzene, 1,3-bis(3-aminophenoxy)benzene, 9,9-bis(4-aminophenyl)-10-hydroanthracene, 2, 7-diaminofluorene, 9,9-bis(4-aminophenyl)fluorene, 4,4'-methylene-bis(2-chloroaniline), 2,2',5,5'-tetrachloro Base-4,4'-diaminodiphenyl, 2,2'-dichloro-4,4'-diamino-5,5'-dimethoxydiphenyl, 3,3'-dimethyl Oxy-4,4'-diaminodiphenyl, 1,4,4'-(P-phenyleneisopropylidene)diphenylamine, 4,4'-(m-phenyleneisopropylidene ) diphenylamine, 2,2'-bis[4-(4-amino-2-trifluoromethylphenoxy)phenyl]hexafluoropropane, 4,4'-diamino-2,2'-bis( Trifluoromethyl)diphenyl, 4,4'-bis[(4-amino-2-trifluoromethyl)phenoxy]-octylfluorodiphenyl and diamines represented by the following structural formula (3): Aromatic diamines with one heteroatom, such as diaminotetraphenylthiophene; aliphatic or cycloaliphatic diamines, such as 1,1-m-xylylene, 1,3-propanediamine, tetramethylenediamine Amines, Pentamethylenediamine, Hexamethylenediamine, Heptamethylenediamine, Octamethylenediamine, Nonamethylenediamine, 4,4-Diaminoheptamethylenediamine, 1,4-Diaminocyclohexane, Isophorone, Tetrahydrodicyclopentadienylidenediamine, Hexahydro-4,7-methyleneindenylidene dimethylenediamine , tricyclo[6,2,1,0 ^2.7 ]-undecenedimethyldiamine and 4,4'-methylenebis(cyclohexylamine); substituted by an alkyl group represented by the following structural formula (4) of phenylenediamines:

Wherein R ⁹ , R ¹⁰ , R ¹¹ and R ¹² are hydrogen atoms or alkyl groups, such as methyl, ethyl or

Isopropyl groups such as p-phenylenediamine and 2,3,5,6-tetramethyl-1,4-diaminobenzene; substituted diphenylmethanes represented by the following structural formula (5):

wherein R ¹³ , R ¹⁴ , R ¹⁵ , R ¹⁶ , R ¹⁷ , R ¹⁸ , R ¹⁹ and R ²⁰ are each a hydrogen atom

or an alkyl group, such as methyl, ethyl, or isopropyl, such as 4,4'-diaminophenylmethane and 3,3'-diethyl-4,4'-diaminodiphenylmethane; Substituted phenylenediamines represented by the following structural formula (6):

where R ²¹ is derived from -O-, -COO-, -OCO-, -NHCO-, -CONH- and -CO-

A divalent organic group selected in the group, R ²² is a monovalent organic group, such as a diamine represented by the following structural formula (7): and has a steroidal skeleton at ^R22 ; 3,5-diamino-4'-trifluoromethylbenzanilide and 3,5-diamino-3'- with a trifluoromethylphenyl group Trifluoromethylbenzanilide; a diaminoorganosiloxane represented by the following structural formula (8):

wherein ^R is a hydrocarbon group having 1 to 12 carbon atoms, i.e. an alkyl group,

such as methyl, ethyl or propyl, a cycloalkyl group such as cyclohexyl, or a

Aromatic group, such as phenyl, P is an integer from 1 to 3, q is an integer from 1 to 20

number; and similar components.

Among these components, preferred are P-phenylenediamine, 2,3,5,6-tetramethyl-1,4-diaminobenzene, 4,4'-diaminodiphenylmethane, 3, 3'-diethyl-4,4'-diaminodiphenylmethane, 1,5-diaminonaphthalene, 2,7-diaminofluorene, 4,4'-diaminodiphenylsulfide, 4, 4'-diphenyl ether, 9,9-bis(4-aminophenyl)fluorene, 2,2-bis[4-(4-aminophenoxy]hexafluoropropane, 2,2'-bis[4 -(4-amino-2-trifluoromethylphenoxy)phenyl]hexafluoropropane, 4,4'-diamino-2,2'-bis(trifluoromethyl)diphenyl,4,4 '-bis[(4-amino-2-trifluoromethyl)phenoxy]-octafluorodiphenyl, 3,5-amino-4'-trifluoromethylbenzanilide, 3,5-di Amino-3'-trifluoromethylbenzanilide and diamines represented by the above structural formula (8). Particularly preferred are P-phenylenediamines, 4,4'-diaminodiphenylmethane, 4, 4'-diaminodiphenylsulfide, 3,5-diamino-4'-trifluoromethylbenzanilide, 3,5-diamino-3'-trifluoromethylbenzanilide and The diamine represented by the above structural formula (8). They can be used alone, or two or more can be used in combination. The examples of anhydrides that are applicable to terminal variants include maleic anhydride, phthalic anhydride and the following structural formula (9 ) represents the compound:

Specific examples of monoamines for use in terminal variants include: aniline, cyclohexylamine, n-butylamine, n-pentylamine, n-hexylamine, n-heptylamine, n-octylamine, n-nonylamine, n- -decylamine, n-undecylamine, n-dodecylamine, n-tridecylamine, n-tetradecylamine, n-pentadecylamine, n-hexadecylamine, n-heptadecanylamine, n-octadecylamine Amines, n-eicosamine and similar substances.

The aliphatic or alicyclic hydrocarbon group containing an aliphatic hydrocarbon group or alicyclic hydrocarbon group at R ¹ , R ² , R ³ and R ⁴ of the specific structural units I and II of the present invention is selected from aliphatic or alicyclic tetrahydrocarbyl Carboxylic dianhydrides, aliphatic or cycloaliphatic diamines, or derivatives of tetracarboxylic dianhydrides or diamines containing an aliphatic or cycloaliphatic hydrocarbon group as described above.

The specific polymer used in the present invention can be obtained by reacting tetracarboxylic dianhydride with a diamine compound in an organic solvent at a reaction temperature of preferably 0 to 150°C, particularly preferably at a reaction temperature of 0 to 100°C I. The ratio of the tetracarboxylic dianhydride to the diamine compound is as follows: The amount of the acid anhydride group of the tetracarboxylic dianhydride per equivalent of the amino group of the diamine compound is preferably 0.2 to 2 equivalents, more preferably 0.3 to 1.2 equivalents. As described above, an acid anhydride or monoamine for terminal modification may be added at the time of this reaction.

The organic solvent is not particularly limited as long as it can dissolve the specific polymer I formed by the reaction. Illustrative examples of organic solvents include: aprotic polar solvents such as N-methyl-2-pyrrolidone, N,N-dimethylacetamide, N,N-dimethylformamide, dimethylsulfoxide , γ-butyrolactone, tetramethylurea and hexamethylphosphoric triamide; and phenolic solvents such as m-cresol, xylenol, phenol and halogenated phenols. It is preferable to set the amount of the organic solvent used so that the amount of the tetracarboxylic dianhydride and the diamine compound accounts for 0.1 to 30% by weight of the total amount of the reaction solvent.

The specific polymer II used in the present invention can be obtained by imidating the above specific polymer I under heating in the presence of a dehydrating agent and an imidization catalyst. The reaction temperature range for the above imidation under heating is preferably 60 to 250°C, more preferably 100 to 170°C. When the reaction temperature is lower than 60°C, the reaction proceeds slowly, while when the reaction temperature is higher than 250°C, the molecular weight of the specific polymer II tends to decrease much. The imidation can be performed in the above-mentioned organic solvent in the presence of a dehydrating agent and an imidization catalyst. The reaction temperature is preferably in the range of 0 to 180°C, more preferably in the range of 60 to 150°C. For example, the dehydrating agent can be selected from acid anhydrides such as acetic anhydride, propionic anhydride and trifluoroacetic acid. For example, the imidization catalyst can be selected from tertiary amines such as pyridine, collidine, lutidine and trifluoroacetic anhydride. The dehydrating agent is preferably used in an amount of 1.6 to 20 moles per molar equivalent of the repeating unit of the specific polymer I. The amount of the imidization catalyst used is preferably 0.5 to 10 moles per mole of the dehydrating agent used.

The above-mentioned organic solvents may be mixed with poor solvents for the specific polymer II (such as alcohols, ketones, esters, ethers, halogenated hydrocarbons or hydrocarbons) to such an extent that the specific polymer II does not precipitate out. For example, poor solvents can be selected from the following substances: alcohols, such as methanol, ethanol, isopropanol, cyclohexanol, ethylene glycol, propylene glycol, 1,4-butanediol, triethylene glycol , and ethylene glycol monomethyl ether; ketones, such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; esters, such as methyl acetate, ethyl acetate, butyl Acetate, diethyl oxalate and diethyl malonate; ethers such as diethyl ether, ethylene glycol methyl ether, ethylene glycol ethyl ether, ethylene glycol-n -Propyl ether, Ethylene glycol-i-propyl ether, Ethylene glycol-n-butyl ether, Ethylene glycol dimethyl ether, Ethylene glycol ethyl ether acetate , diethylene glycol dimethyl ether and tetrahydrofuran; halogenated hydrocarbons such as dichloromethane, 1,2-dichloroethane, 1,4-dichlorobutane, trichloroethane, chlorobenzene and O-dichlorobenzene; hydrocarbons such as hexane, heptane, octane, benzene, toluene and xylene.

The specific polymer I or II thus obtained has an intrinsic viscosity preferably in the range of 0.05 to 10 dl/g, more preferably in the range of 0.05 to 5 dl/g (when under such conditions [ηinh=(lnηrel/c, C=0.5g /dl, at 30°C, in N-methyl-2-pyrrolidone), the following intrinsic viscosity values are measured under such conditions]).

The liquid crystal aligning agent of the present invention may contain a silane coupling agent for the purpose of increasing the viscosity of the specific polymer I and/or polymer II to the substrate.

Illustrative examples of silane coupling agents include: 3-aminopropyltrimethoxysilane, 3-aminopropyltrihexyloxysilane, 2-aminopropyltrimethoxysilane, 2-aminopropyltriethoxysilane , N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane, 3-ureidopropyl Triethoxysilane, N-ethoxycarbonyl-3-aminopropyltrimethoxysilane, N-ethoxycarbonyl-3-aminopropyltriethoxysilane, N-triethoxysilylpropane Triethylenetriamine, N-trimethoxysilylpropyltriethylenetriamine, 10-trimethoxysilyl-1,4-7-triazadecane, 10-triethoxy Silyl-1,4,7-triazadecane, 9-trimethoxysilyl-3,6-diazanonyl acetate, 9-triethoxysilyl-3, 6-diazanonyl acetate, N-benzyl-3-aminopropyltrimethoxysilane, N-benzyl-3-aminopropyltriethoxysilane, N-phenyl-3 -aminopropyltrimethoxysilane, N-phenyl-3-aminopropyltriethoxysilane, N-bis(oxyethylene)-3-aminopropyltrimethoxysilane, N-bis( oxyethylene)-3-aminopropyltriethoxysilane and similar substances.

The liquid crystal aligning agent of the present invention may include some additives, such as a photosensitizer, a photoinitiator (Photoradical generator) and an acid-forming agent by light irradiation, so as to improve sensitivity to radiation.

A typical example of a photosensitizer, a photoinitiator (Photoradical generator), and a reagent that forms an acid by light irradiation is a coumarin, such as 3-benzoylbenzo[f]coumarin (manufactured by Kodak Corporation), respectively. A ketone-containing compound such as CGI-369 (manufactured by CIBAGEIGY), and a triazine compound such as 2,4-bis(trichloromethyl)-6-(4'-methoxynaphthyl)- S-triazine.

The liquid crystal aligning agent of the present invention exhibits the ability to change the pretilt angle of liquid crystal when the film formed from the liquid crystal aligning agent after exposure is compared with the film before exposure.

Utilizing this characteristic of the liquid crystal aligning agent of the present invention, the following method can be used to manufacture a segmented liquid crystal display (see Figure 5).

Can adopt roll coating, any one method among spin coating and printing method and pre-bake at 60 to 100 ℃ and at first be coated with the liquid crystal alignment agent of the present invention on the transparent conductive film side of the substrate with transparent conductive film . Then, the liquid crystal aligning film thus obtained is partially exposed with, for example, ultraviolet rays through a mask having a predetermined pattern, and then post-baked at a temperature of 120 to 300°C, preferably 130 to 250°C. The thickness of the finally obtained coating is usually 0.001 to 1 µm, preferably 0.005 to 0.5 µm. The pretilt angle of the exposed area is different from the pretilt angle of the unexposed area. The difference in pretilt angle is about 2° to 10° in one pixel.

The radiation is not particularly limited as long as the radiation can induce the above-mentioned changes in the film, and ultraviolet rays, electron beams, X-rays and laser beams can be used. Among these radiations, it is preferable that the radiation has a wavelength of 300 nm or less. Ultraviolet rays emitted from metal halide lamps, mercury xenon lamps, low-pressure mercury lamps, high-pressure mercury lamps or the like are particularly preferable as the light source from the standpoint of possibility of batch exposure.

A liquid crystal alignment film is formed by grinding the above-formed film with a roll wrapped with synthetic fibers such as nylon. The coating is exposed to radiation after post-baking or grinding the coating.

The aforementioned substrate can be selected from glass (such as float glass and soda glass) and plastic films of polyethylene terephthalate, polytetramethylene terephthalate, polyether sulfone, polycarbonate and the like. Formed transparent substrate.

The above-mentioned transparent conductive film is selected from a NESA film _composed of _SnO2 , an ITO film composed of _In2O3 - _SnO2 , and the like. A pattern can be formed on the transparent conductive film by photolithography or by using a mask in advance.

In order to further improve the adhesion of the substrate and the transparent conductive film to the coating, a silane coupling agent or a titanium coupling agent can be coated on the substrate and the transparent conductive film before coating the liquid crystal alignment agent.

It is preferable to place two substrates in such a way that a liquid crystal alignment film with a pattern having a different pretilt angle in one pixel is formed on each of the two substrates so that the liquid crystal alignment films are opposed to each other, and their The grinding direction is at right angles or antiparallel, and also makes the high pretilt angle region and the low pretilt angle region of the film between the upper and lower substrates face each other, the edge region between the substrates is sealed with a sealant, filled with liquid crystals, And the filling hole was sealed to form a liquid crystal cell. Polarizers were installed on each side of the liquid crystal cell in such a manner that the polarization direction of each polarizer was in line with or at right angles to the grinding direction of the liquid crystal alignment film. Thus, a liquid crystal display was fabricated.

An epoxy resin containing a curing agent and aluminum oxide particles as spacers can be used as the sealant.

As the liquid crystal, nematic liquid crystal and smectic liquid crystal can be used. Among them, nematic liquid crystals are preferably used. The liquid crystal can be selected from: Schiff base liquid crystal, azo oxide liquid crystal, diphenyl liquid crystal, phenylcyclohexane liquid crystal, ester liquid crystal, terphenyl liquid crystal, diphenylcyclohexane liquid crystal, pyrimidine liquid crystal, dioxane liquid crystal , Two cyclooctane liquid crystals, cubic ane liquid crystals and so on. In addition, the liquid crystals may contain cholesteric liquid crystals such as cholesteryl chloride, cholesteryl nonanoate and cholesteryl carbonate, and commercially available chiral reagents such as C-15 and CB-15 (trade names, produced by Merck Ltd.). Alternatively, ferroelectric liquid crystals such as P-dessiloxybenzylidene-P-amino-2-methylbutyl cinnamate may be used.

The polarizing plate installed outside the liquid crystal cell can be selected from such polarizing plates that can be formed by stretching to orient polyvinyl alcohol so that it can absorb iodine to form an orientation film called H film and then sandwich the polarizing film between cellulose acetate Such a polarizing plate obtained between protective films may be selected from polarizing plates formed only of an H film.

According to the present invention, by selectively exposing the liquid crystal alignment film with radiation, a liquid crystal alignment film in which the pretilt angle can be changed by radiation with small radiation energy can be obtained, and a liquid crystal display with a wide viewing angle and excellent reliability can be easily obtained . The alignment film is exposed to radiation and absorbs its energy, so the surface state of the alignment film changes due to a change in the pretilt angle.

The most suitable radiation for the liquid crystal aligning agent of the present invention is ultraviolet rays and laser light. In order to obtain a pretilt angle difference of 2 "that can well control the orientation, generally need 20J/cm ² or greater radiation dose (metal halide lamp, 365nm). In addition, use the orientation film formed by the liquid crystal aligning agent of the present invention, The amount of radiation required can be reduced to 10J/ ^cm2 or less, so it is possible to produce liquid crystal displays with wide viewing angles very efficiently. Since the liquid crystal displays produced in this way do not require a photolithography process, the liquid crystal properties will not be damaged, thereby Its reliability is good.

The present invention is explained in further detail below with reference to Examples. However, the present invention is not limited to these examples.

The measurement of the pretilt angle described in the examples was carried out with the crystal rotation method using a HeNe laser according to the method described by T.J. Scheffer et al. in J. Appl. Phys., 19, 2013 (1980).

The alignment characteristics of the liquid crystal cell were evaluated as follows: When the voltage was turned on and the voltage was turned off, the liquid crystal cell was observed through a polarizing microscope to see whether there were abnormal areas. Such a liquid crystal cell is considered good when there are no abnormal areas.

The measurement of the pretilt angle was performed using a liquid crystal cell made by stacking two substrates in such a way that the rubbing directions of the two substrates were antiparallel, and between the two substrates The regions with high pretilt angles face each other, and the regions with low pretilt angles also face each other (see Figure 6).

Evaluation of alignment characteristics was performed using a liquid crystal cell manufactured by laminating two substrates in such a manner that the rubbing directions of the two substrates were at right angles, with each A high pretilt area is opposite to a low pretilt area (see Figure 7). Synthetic Example 1

With 29.80 grams of 2,3,5-tricarboxycyclopentyl acetate dianhydride (hereinafter referred to as acid anhydride), 14.16 grams of P-phenylenediamine, and 1.04 grams of di The amine was dissolved in 405 g of N-methyl-2-pyrrolidone, and the mixture was reacted at 60°C for 6 hours.

The reaction mixture was poured into excess methanol to precipitate the reaction product. After that, the reaction product was washed with methanol and baked at 40°C for 15 hours under reduced pressure to give 40.35 g of specific polymer I(Ia) having an intrinsic viscosity of 1.06 dl/g. Synthetic example 2

800 g of N-methyl-2-pyrrolidone, 52.58 g of pyridine and 40.71 g of acetic anhydride were added to 40.00 g of specific polymer I (Ia) obtained in Synthesis Example 1, and the mixture was imidized at 115° C. 4 hours.

After that, the reaction product solution was precipitated in the same manner as in Synthesis Example 1 to obtain 35.65 g of Specific Polymer II (IIa) having an intrinsic viscosity of 1.08 dl/g. Synthetic Example 3

Except for the following changes, the steps of Synthetic Example 1 were repeated: the amount of acid anhydride was changed to 28.58 grams, the amount of P-phenylenediamine was changed to 13.10 grams, and the amount of diamine represented by the above structural formula (8) was changed to 3.32 grams to produce A particular polymer I (Ib). Furthermore, in the same manner as in Synthesis Example 2, imidization reaction was performed using this specific polymer I(Ib) to obtain 36.30 g of specific polymer II(IIb) having an intrinsic viscosity of 0.99 dl/g . Synthetic Example 4

Except following change, repeat the step of synthetic example 1: the amount of acid anhydride is changed into 27.00 grams, the amount of P-phenylenediamine is changed into 11.72 grams and the amount of the diamine represented by above-mentioned structural formula (8) is changed into 6.28 grams or more A specific polymer I (Ic) is obtained. Also, using this specific polymer I(Ic), imidization was performed in the same manner as in Synthesis Example 2 to obtain 36.55 g of specific polymer II(IIc) having an intrinsic viscosity of 0.94 dl/g. Synthetic Example 5

Except the following changes, repeat the steps of Synthetic Example 1: adopt 26.24 grams of acid anhydride, 10.13 grams of P-phenylenediamine, 6.10 grams of diamine represented by the above structural formula (8), and 2.53 grams of diamine used as diamine 4,4'-diaminodiphenyl sulfide to produce a specific polymer I (Id), in addition, using this specific polymer I (Id), imidization is carried out in the same manner as in Synthesis Example 2 The reaction yielded 35.43 g of specific polymer II(IId) having an intrinsic viscosity of 0.92 dl/g. Synthetic Example 6

Except following change, repeat the step of synthetic example 1: adopt the acid anhydride of 20.05 grams, the 4 of 13.30 grams, 4 '-diaminodiphenylmethane and 11.65 grams are used as the diamine represented by the above structural formula (8) as diamine Obtain a kind of specific polymer I (Ie), in addition, utilize this specific polymer I (Ie), carry out imidization reaction in the same manner as synthetic example 2, obtain the intrinsic viscosity of 36.07 grams and be 0.91 deciliter per gram of specific polymer II(IIe). Synthetic Example 7

Except for the following changes, the steps of Synthetic Example 1 were repeated: using 25.12 grams of anhydride, 4.85 grams of P-phenylenediamine, 9.20 grams of 2,3,5,6-tetramethyl-1,4-diaminobenzene and 5.84 grams of the diamine represented by the above formula (8) was used as the diamine to produce a specific polymer I(If). Also, using this specific polymer I(If), imidization was carried out in the same manner as in Synthesis Example 2 to obtain 36.60 g of specific polymer II(IIf) having an intrinsic viscosity of 0.99 dl/g. Synthetic Example 8

Except following change, repeat the step of synthetic example 1: adopt the acid anhydride of 19.25 grams, 14.57 grams of 3,3 '-dimethyl-4,4'-diaminodiphenylmethane and 11.18 grams of diaminodiphenylmethane by as diamine The diamine represented by the above structural formula (8) to obtain a specific polymer I (Ig). Also, using this specific polymer I (Ig), imidization was carried out in the same manner as in Synthesis Example 2 to obtain 35.30 g of specific polymer II (IIg) having an intrinsic viscosity of 0.94 dl/g. Synthetic Example 9

Except following change, repeat the step of synthetic example 1: the acid anhydride of 23.47 grams, the P-phenylenediamine of 7.36 grams, the diamine represented by above-mentioned structural formula (4) of 8.18 grams and 6.00 grams of diamine as diamine by above Diamine represented by structural formula (8) to produce a specific polymer I(Ih). Also, using this specific polymer I(Ih), imidization was carried out in the same manner as in Synthesis Example 2 to obtain 35.44 g of specific polymer II(IIh) having an intrinsic viscosity of 0.96 dl/g. Synthetic Example 10

Except following change, repeat the step of synthetic example 1: adopt the acid anhydride of 29.98 grams, the P-phenylenediamine of 13.42 grams, the diamine represented by structural formula (8) of 1.35 grams and the n- as diamine of 1.25 grams cetylamine to produce a specific polymer I(Ii). Also, using this specific polymer I(Ii), imidization was carried out in the same manner as in Synthesis Example 2 to obtain 34.85 g of specific polymer II(IIi) having an intrinsic viscosity of 0.93 dl/g. Synthetic Example 11

The procedure of Synthetic Example 1 was repeated except for the following changes: 28.74 grams of anhydride, 13.17 grams of P-phenylenediamine as diamine and 3.09 grams of n-hexadecylamine as monoamine were used to produce a specific Polymer I(Ij). Also, using this specific polymer, imidization was performed in the same manner as in Synthesis Example 2 to obtain 34.08 g of specific polymer II(IIj) having an intrinsic viscosity of 0.89 dl/g. Synthetic Example 12

The steps of Synthetic Example 1 were repeated except for the following changes: 26.14 grams of 5-(2,5-dioxotetrahydrofuryl)-3-methyl-3-cyclohexane-1,2- Dicarboxylic dianhydride, 8.56 g of P-phenylenediamine, and 10.30 g of a diamine represented by the above formula (8) as a diamine to produce a specific polymer I(Ik). Also, using this specific polymer I(Ik), imidization was performed in the same manner as in Synthesis Example 2 to obtain 34.90 g of specific polymer II(IIk) having an intrinsic viscosity of 0.88 dl/g. Synthetic Example 13

The procedure of Synthetic Example 1 was repeated except for the following changes: using 27.52 grams of 1,3,3a,4,5,9b-hexahydro-5-tetrahydro-2,5-dioxy-3-furan as an anhydride base)-naphtho[1,2-c]-furan-1,3-dione, 7.93 g of P-phenylenediamine and 9.55 g of the diamine represented by the above structural formula (8) as diamine and One particular polymer I (Il) was produced. Also, using this specific polymer I(Il), imidization reaction was carried out in the same manner as compound example 2 to obtain 34.30 g of specific polymer II(IIl) having an intrinsic viscosity of 0.87 dl/g. Synthetic Example 14

The steps of Synthetic Example 1 were repeated except for the following changes: 25.45 grams of bicyclo[2,2,2]-oct-7-ene-2,3,5,6-tetracarboxylic anhydride as an acid anhydride was used, 8.87 g of P-phenylenediamine and 10.68 g of diamine represented by the above structural formula (8) as diamine to produce a specific polymer I(Im), in addition, using this specific polymer I( Im), carry out imidization reaction in the same manner as Synthetic Example 2, to obtain 36.51 grams of specific polymer II (IIm) with an intrinsic viscosity of 0.86 deciliters/gram. Synthetic Example 15

Except for the following changes, the steps of Synthetic Example 1 were repeated: using 32.78 grams of anhydride, 7.91 grams of P-phenylenediamine and 4.32 grams of 3,5-diamino-4'-trifluoromethyl as diamine Benzanilide to produce a specific polymer I(In), in addition, using this specific polymer I(In), carry out imidation in the same manner as in Synthesis Example 2 to obtain an intrinsic viscosity of 36.40 g is 0.91 dl/g of specific polymer II(IIn). Synthetic Example 16

Except for the following changes, the steps of Synthetic Example 1 were repeated: 32.78 grams of anhydride, 7.91 grams of P-phenylenediamine and 4.32 grams of 3,5-diamino-3'-trifluoromethylbenzene were used as diamine Formanilide is to produce a kind of specific polymer I (Io), in addition, utilize this specific polymer I (Io), carry out imidization reaction in the same manner as synthetic example 2, obtain the intrinsic viscosity of 36.45 grams as 0.89 dl/g of specific polymer II(IIo). Synthetic Example 17

Except for the following changes, the steps of Synthetic Example 1 were repeated: using 15.14 grams of anhydride, 2.74 grams of P-phenylenediamine and 27.12 grams of 2,2-bis[4-(4-amino-2-tris Fluoromethylphenoxy)-phenyl]hexafluoropropane to produce a specific polymer I (Ip), in addition, using this specific polymer I (Ip), according to the same manner as Synthesis Example 2 to carry out imidization The amination reaction gave 36.54 g of specific polymer II (IIp) with an intrinsic viscosity of 0.92 dl/g. Synthetic Example 18

Except following change, repeat the step of synthetic example 1: adopt the acid anhydride of 25.94 grams, the P-phenylenediamine of 9.39 grams and the 2,2-bis(4-aminophenyl) hexafluoropropane of 9.67 grams as diamine To produce a specific polymer I (Iq), in addition, using this specific polymer I (Iq), carry out the imidization reaction in the same manner as in Synthesis Example 2, to obtain 36.00 grams of intrinsic viscosity of 0.92 deciliters per gram of specific polymer II(IIq). Synthetic Example 19

Except following change, repeat the step of synthetic example 1: adopt the 1,2,3,4-cyclobutanetetracarboxylic dianhydride of 25.54 grams as acid anhydride, the P-phenylenediamine of 12.68 grams and the 6.78 grams of diamine represented by the above formula (8) to yield 39.76 grams of a particular polymer I(Ir). Synthetic Example 20

Except for the following changes, the steps of Synthetic Example 1 were repeated: using 21.51 grams of 1,2,3,4-cyclobutanetetracarboxylic dianhydride as an anhydride, and 5.93 grams of P-phenylenediamine and as diamine 17.5 grams of 4,4'-diamino-2,2'-bis(trioxymethyl)biphenyl to yield 40.12 grams of a specific polymer I(Is). Synthetic Example 21

The steps of Synthetic Example 1 were repeated except for the following changes: 14.55 grams of 1,2,3,4-cyclobutanetetracarboxylic dianhydride as an acid anhydride, and 30.45 grams of 2 as a diamine, 2-bis[4-(4-aminophenoxy)phenyl]propane to yield 39.11 g of one particular polymer I(It). Synthetic Example 22

Except for the following changes, the steps of Synthetic Example 1 were repeated: using 14.46 grams of 1,2,3,4-cyclobutanetetracarboxylic dianhydride as an acid anhydride, 28.76 grams of 2,2- Bis[4-(4-aminophenoxy)phenyl]propane, and 1.78 grams of n-hexadecylamine as the monoamine to yield 40.54 grams of a particular polymer I(Iu). Synthetic Example 23

Except following change, repeat the step of synthetic example 1: adopt the pyromellitic dianhydride of 28.30 grams as a kind of acid anhydride, and the P-phenylenediamine of 13.33 grams and 3.34 grams of as diamine by the above structural formula ( 7) The represented diamines yielded 39.76 g of a particular polymer I(Iv). Synthetic Example 24

Except for the following changes, the steps of Synthetic Example 1 were repeated: using 26.99 grams of pyromellitic dianhydride as an anhydride, 12.04 grams of P-phenylenediamine as a diamine, and 5.97 grams of n as a monoamine - Hexadecylamine to yield 39.77 grams of a particular polymer I(Iw). Synthetic Example 25

Except the following changes, the steps of Synthetic Example 1 were repeated: using 22.70 grams of pyromellitic dianhydride as acid anhydride, and 5.63 grams of P-phenylenediamine and 16.67 grams of 4,4'-diamino as diamine -2,2'-bis(trifluoromethyl)biphenyl to yield 40.16 g of one specific polymer I(Ix). Synthetic Example 26

Except for the following changes, the steps of Synthetic Example 1 were repeated: using 23.38 grams of pyromellitic dianhydride as an acid anhydride, and 5.80 grams of P-phenylenediamine and 15.82 grams of 3.5-diamine as diamine. Amino-3'-trifluoromethylbenzanilide to yield 40.22 g of one particular polymer I(Iy). Example 1

5 g of the specific polymer (IIa) obtained in Synthesis Example 2 above was dissolved in 120 g of γ-butyrolactone to prepare a solution with a solid content of 4% by weight. The solution was filtered with a filter having a mesh of 1 micron to obtain a liquid crystal aligning agent solution.

The solution obtained above was applied to the transparent electrode side of each of two glass substrates having an ITO thin film transparent electrode with a spin coater at a spin rate of 3,000 revolutions per 3 minutes, and heated at 100° C. Prebake for 30 seconds.

Next, through a 3 × 3 cm pattern mask for liquid crystal display for pretilt angle measurement and a 100 × 100 micron pattern mask for liquid crystal display for orientation characteristic measurement, the substrate was exposed to a Ultraviolet light emitted by metal halide lamps (light intensity of 10 J/ ^cm2 at a wavelength of 365 nm). Thereafter, the substrate was post-baked at 180°C for 1 hour to form a cover film of 0.05 µm thick. The amount of the specific structural unit II in the polymer constituting the covering film was 92 mole percent (mol%).

The cover film was ground using a grinding machine with a drum with a 0.6 mm laminate (pile compression) nylon fabric. Thereafter, the cover film was cleaned with an isopropanol vapor to produce a substrate having a liquid crystal alignment film having a certain shape and a difference in tilt angle in one pixel.

Then, an epoxy resin adhesive containing alumina particles having a diameter of 17 µm was applied to the border area of each substrate on the grinding-treated liquid crystal alignment film side by screen printing. Then, the two substrates were bonded to each other under pressure so that the surfaces of the liquid crystal alignment films faced each other, and the adhesive was cured.

Next, a nematic liquid crystal (MLC-2001 manufactured by Merk Corporation) was introduced into the space between the substrates from a liquid crystal-filled hole, and the hole was sealed with an epoxy adhesive. Polarizers are connected to both outer surfaces of the substrate so that the polarization direction of each polarizer is consistent with the grinding direction of the corresponding liquid crystal alignment film to produce a liquid crystal display.

Therefore, when the produced liquid crystal display was used for pretilt angle measurement, it was found that there was a large difference in pretilt angle due to exposure to ultraviolet rays, ie, the pretilt angle was 0.7° in the exposed area and 3.5° in the unexposed area. The alignment characteristics of the liquid crystal display were good in both regions. Example 2

The liquid crystal aligning film obtained in Example 1 was used to prepare a liquid crystal display.

As shown in FIG. 8, pixel regions 12 and 13 are formed in a substrate 11 and covered with a liquid crystal alignment film 14. As shown in FIG. A mask 15 used in a radiation exposure step to be described hereinafter is placed at a position facing the surface of the substrate. According to this example, the pixel regions 12 and 13 are formed in the substrate 1 by a conventional method. Then, a liquid crystal alignment film 14 is formed on the entire surface of the substrate 11 so as to cover the pixel regions 12 and 13 . In this example, the liquid crystal aligning agent obtained in Example 1 was used as the liquid crystal aligning film 14 to form a 0.05 micron thick liquid crystal aligning film. The amount of the specific structural unit II in the polymer forming the liquid crystal alignment film was 92 mole percent. After prebaking, the cover film of the liquid crystal aligning agent is subjected to grinding treatment. Thereafter, the liquid crystal aligning film 14 is exposed by irradiation 16 . The irradiation 16 exposure step can be performed at any time after the formation of the liquid crystal alignment film, ie, after the steps of applying the liquid crystal alignment agent, pre-baking, post-baking and grinding.

In the case of radiation exposure using the mask 15 , the shaded 15 a represents the coverage area that does not pass through the radiation 16 , while the non-hatched 15 b represents the coverage area that passes through the radiation 16 . The light-transmitting area faces part of the pixel area, and a photomask similar to that commonly used is used as the mask 15, or concentrated irradiation is applied to a desired area of the substrate without a mask.

Since irradiation is applied to the liquid crystal alignment film 14, ultraviolet rays are used in this example.

After both the upper and lower substrates constituting the liquid crystal display are exposed to radiation, the two substrates are stacked in such a manner that the exposed area and the unexposed area face each other. Since the unexposed areas, which are high-tilt areas, control the orientation direction of each pixel area, normal and opposite viewing directions can be formed in each pixel. Therefore, the obtained liquid crystal display has no inversion phenomenon along the normal line and the opposite viewing direction, and does not have a sharp drop in contrast, and has a wider viewing angle of 80° compared with the conventional viewing angle of 45°. Examples 3 to 18

The procedure of Example 1 was repeated except for the following changes: Specific polymers IIb to IIq obtained in Synthesis Examples 3 to 18 were used to prepare liquid crystal displays. The alignment characteristics and pretilt angles of the liquid crystal display at the exposed area and the unexposed area were measured, and the results are shown in Table 1.

Table 1 example Specific Polymer II Contains aliphatic/alicyclic hydrocarbon groups Pretilt angle(°) Liquid crystal alignment characteristics Specific structural unit II content (*) exposure part unexposed part Dianhydride diamine the end 3 IIb ○ ○ - 0.9 7.0 good 93 4 IIc ○ ○ - 2.3 10.5 ditto 94 5 IId ○ ○ - 1.8 9.8 ditto 89 6 IIe ○ ○ - 2.5 10.4 ditto 93 7 If ○ ○ - 2.3 8.2 ditto 85 8 IIg ○ ○ - 2.0 6.9 ditto 78 9 IIh ○ ○ - 2.0 7.0 ditto 92 10 III ○ ○ ○ 1.5 9.2 ditto 92 11 IIj ○ - ○ 2.0 5.4 ditto 95 12 IIk ○ ○ - 2.4 6.0 ditto 100 13 III ○ ○ - 2.5 5.9 ditto 87 14 IIm ○ - - 2.7 6.3 ditto 100 15 IIn ○ - - 2.4 6.9 ditto 98 16 IIo ○ - - 2.1 4.2 ditto 80 17 IIp ○ - - 1.4 3.5 ditto 75 18 IIq ○ - - 0.9 3.0 ditto 99 (Note) * The amount is the content (mol%) of the specific structural unit II in the polymer forming the liquid crystal alignment film Examples 19 to 23

Except for the following changes, the steps of Example 1 were repeated: using the specific polymer Ir or Iv obtained from Synthesis Examples 19 to 23, after post-baking, exposure was carried out at 250° C. for 1 hour, and a nematic liquid crystal (ZLI-2293, produced by Merck Corporation) to prepare a liquid crystal display. The alignment characteristics and pretilt angles of the liquid crystal display were measured, and the results are shown in Table 2.

Table 2 example Specific Polymer II Contains aliphatic/alicyclic hydrocarbon groups Pretilt angle(°) Liquid crystal alignment characteristics Specific structural unit II content (*) exposure part unexposed part Dianhydride diamine the end 19 Il ○ ○ - 0.4 8.3 good 90 20 Is ○ - - 0.7 7.5 ditto 85 twenty one Il ○ - - 0.4 4.1 ditto 90 twenty two Iu ○ - ○ 0.5 6.8 ditto 96 twenty three IV - ○ - 3.5 8.5 ditto 94 (Note) *The definitions given in Table 1 also apply to Table 2. Comparative example 1

The procedure of Example 1 was repeated except for the following changes: using the specific polymer I(Iw) obtained in Synthesis Example 24 to prepare a liquid crystal display. When the pretilt angles of the liquid crystal display devices were measured, it was found that there was only a slight difference between the pretilt angles due to exposure to ultraviolet rays, ie, the pretilt angles were 4.6° in the exposed area and 5.5° in the unexposed area. As a result, a desired segmented alignment type liquid crystal display cannot be obtained. Comparative example 2

The procedures of Examples 19 to 23 were repeated except for the following changes: using the specific polymer I(Ix) obtained in Synthesis Example 25 to prepare a liquid crystal display. When the pretilt angle of the liquid crystal display was measured, it was found that there was only a small difference in the pretilt angle due to exposure to ultraviolet light, ie, the pretilt angle was 5.3° in the exposed area and 5.1° in the unexposed area. As a result, a desired segmented alignment type liquid crystal display cannot be obtained. Comparative example 3

The procedures of Examples 19 to 23 were repeated except for the following changes: using the specific polymer I(Iy) obtained in Synthesis Example 26 to prepare a liquid crystal display. When measuring the pretilt angle of the liquid crystal display, it was found that due to exposure with ultraviolet rays, there was only a small difference in the pretilt angle, that is, the pretilt angle of the exposed area was 7.2°, while the pretilt angle of the unexposed area was 7.0°. As a result, the desired Partition orientation liquid crystal display.

The liquid crystal aligning agent of the present invention makes it possible to obtain a zonal alignment type TN-STN display which is suitable for making a kind of display excellent liquid crystal alignment characteristics and produces a large change in pretilt angle with a small irradiation energy and has a wide viewing angle Liquid crystal alignment film becomes possible.

A liquid crystal display having a liquid crystal aligning film formed from the liquid crystal aligning agent of the present invention is applicable to SH (super anisotropic), ferroelectric and antiferroelectric liquid crystal displays by selecting one of the liquid crystals used.

Further, a liquid crystal display having a liquid crystal alignment film formed from the liquid crystal alignment agent of the present invention has excellent liquid crystal alignment characteristics and reliability, and can be effectively used as various types such as desk calculators, watches, clocks, digital displays, Displays for devices and devices such as word processors, personal computers, and LCD televisions.

Claims (8)

1. A liquid crystal aligning agent for a partitioned alignment type liquid crystal display, comprising a polymer containing at least one structural unit selected from the group consisting of structural units represented by (2) of the following structural formula (1) :

Where R ¹ and R ² are tetravalent and divalent organic groups respectively, and at least one of them The group is an aliphatic or alicyclic hydrocarbon group or an aliphatic or alicyclic hydrocarbon group groups of groups, and

Wherein R ³ and R ⁴ are tetravalent and divalent organic groups respectively, and at least one of the groups is an aliphatic or alicyclic hydrocarbon group, or a group containing an aliphatic or alicyclic hydrocarbon group, and when The thin film formed from this liquid crystal aligning agent has the ability to change the pretilt angle of a liquid crystal after irradiation exposure compared with before irradiation exposure. 2. a kind of partition alignment liquid crystal display that has a liquid crystal layer and between each substrate and the liquid crystal layer between a pair of substrates and has a liquid crystal alignment film, it is characterized in that at least one of the liquid crystal alignment films is made of Formed by the liquid crystal aligning agent in claim 1. 3. The liquid crystal display according to claim 2, wherein the liquid crystal alignment film is divided into small regions and processed in such a manner that the surface state of each region is different. 4. A method for making a liquid crystal display comprising the steps of: coating the liquid crystal aligning agent in claim 1 onto at least one of a pair of substrates and baking the substrates to form a liquid crystal aligning film; and The substrate on which the liquid crystal alignment film was formed was partially exposed to radiation. 5. A method for making a liquid crystal display according to claim 4, wherein the liquid crystal aligning agent comprises a polymer, and in the polymer, contains 40 to 100 mol% of the total amount of structural units selected from A structural unit of a group comprising the structural unit represented by the above structural formula (1) and the structural unit represented by the above structural formula (2). 6. A method for making a liquid crystal display according to claim 4, wherein the liquid crystal aligning agent comprises at least one polymer selected from the polymer group represented by the following structural formulas (A) and (B) : wherein ^R1 and ^R2 are tetravalent and divalent organic groups, respectively, at least one of which is an aliphatic or alicyclic hydrocarbon group, or a group containing an aliphatic or alicyclic hydrocarbon group, and n is repeating number of units,

Wherein R ³ and R ⁴ are tetravalent and divalent organic groups respectively, and at least one of them is an aliphatic or alicyclic hydrocarbon group or a group containing aliphatic or alicyclic hydrocarbon groups, and n is repeating the number of units. 7. A method for producing a liquid crystal display as claimed in claim 1, characterized in that said polymer has a characteristic of 0.05 to 10 dl/g when measured in N-methylpyrrolidone at 30°C viscosity. 8. A method for making a liquid crystal display, characterized in that it comprises the following steps: A liquid crystal aligning agent is coated on at least one of a pair of substrates, wherein the aligning agent includes a polymer selected from the following two polymers, one is through at least one of which includes aliphatic or tetracarboxylic dianhydride of at least one hydroxyl group of the cycloaliphatic group and diamine, and another polymer is obtained by imidating the polymer, and baking the cover film to form a liquid crystal alignment film; and The substrate on which the liquid crystal alignment film is formed is partially exposed to radiation.

Images