KR20000005065A - Method and material of inducing pre-tilt in liquid crystal and liquid crystal display device - Google Patents

Abstract

PURPOSE: A pre-tilt inducing method in a liquid crystal and a liquid crystal display device is provided to maintain uniformity of orientation and control a pre-tilt angle of the liquid crystal contacted with an optical orientation layer. CONSTITUTION: The method comprises the steps of exposing one and more optical orienting layer including anisotropic absorption molecule and hydrophobic property residue on polarization light having a wavelength belonging to an absorption band of the molecule to induce liquid crystal media orientation along a surface of the layer and a pre-tilt angle to the surface, coating a liquid crystal media having an isotropic point, heating the media with an over-isotropic temperature, and cooling the media with an under-isotropic temperature.

Description

Methods and materials for inducing pretilt in liquid crystal and liquid crystal display devices

<Before and After Reference of Related Applications>

This application is part of US Application Serial No. 08 / 624,942, filed March 29, 1996.

〈Background of the invention〉

The present invention relates to a method of inducing pretilt in the orientation of a liquid crystal medium, a composition useful for the method and a liquid crystal display device.

The present invention was made with support of the United States Government under the Cooperation Treaty 70NANB4H1525 of the United States Department of Commerce. The US government has clear rights in this invention.

Liquid crystal compounds are used in human and machine readable display elements, which are used in instrument control, such as in automotive, avionics, medical devices, process control devices and watches. The display element mainly consists of a cell in which glass or another substrate coated with a transparent conductor is provided before and after the liquid crystal medium. The light transmittance of such a device is controlled through the orientation of the liquid crystal compound or dye dissolved in the compound. As such, a voltage, or in some cases a magnetic field, may be applied to the cell such that the liquid crystal is oriented in such a way that all or part of the light is passed or not at all. In addition, depending on the geometry of the device, the light transmittance may be adjusted using a polarizer together with a liquid crystal medium.

Commercially oriented liquid crystal cells are typically oriented in a direction suitable for controlling light transmittance. That is, the molecules in the liquid crystal composition are oriented to achieve a uniform or homeotropic orientation. Without external stimulation, the display element will appear opaque or transparent. The molecules are rotated along a fixed axis by applying an electric field to alter the permeability in the desired manner.

Current liquid crystal display devices use a twisted nemaic method (i.e., the structure of the nematic liquid crystal molecules has a birefringent effect with a 90 ° twisted structure between a pair of upper and lower electrode substrates). And a product using a ferroelectric liquid crystal material or a semi-ferroelectric liquid crystal material. Each of these products has in common that a liquid crystal layer is located between a pair of substrates to which a polymer alignment layer is applied. The polymer alignment layer controls the orientation direction of the liquid crystal medium without the electric field. The orientation direction of the liquid crystal medium is achieved by a mechanical buffing process that rubs the polymer layer with a cloth or other fibrous material. The liquid crystal medium in contact with the buffing surface is typically oriented parallel to the mechanical buffing direction. Alternatively, an alignment layer comprising anisotropic absorbing molecules, as described in U.S. Pat.Nos. 5,032,009 and 4,974,941, both of which are entitled "Methods for Orienting and Reorienting Liquid Crystal Media" and are incorporated by reference. The liquid crystal medium may be oriented by exposure to polarized light.

The method of orienting the liquid crystal medium by polarization is a contactless orientation method that can reduce dust and electrostatic charges formed in the alignment layer. Other advantages of the optical alignment method include high resolution alignment control and high quality alignment.

The requirements of the optical alignment layer in the liquid crystal display device include a low orientation energy threshold, transmittance to visible light (colorless), excellent dielectric and voltage retention ratios, long-term thermal and optical stability, and the like in many applications. Uniform pre-tilt angles are required. Most liquid crystal devices, including display devices, have a finite pretilt angle controlled by mechanical buffing of the selected polymer alignment layer, for example. The liquid crystal molecules in contact with this layer are oriented parallel to the buffing direction, but not completely parallel to the substrate. The liquid crystal molecules are slightly inclined from the substrate, for example from 2 to 15 degrees. For optimum performance in most display element applications, a limited uniform pretilt angle of the liquid crystal is desired.

The method of orienting the liquid crystal medium by polarization has many interesting features. However, until now, it was insufficient to control the pretilt angle of the liquid crystal in contact with the optical alignment layer while maintaining the uniformity of the alignment. In addition, the use of anisotropic absorbing molecules that absorb in the visible region has generally not been recognized in order to meet the above mentioned permeability requirements.

<Summary of invention>

The present invention provides a method of inducing pretilt in the orientation of liquid crystal media useful for alignment of liquid crystal display devices and other liquid crystal devices, and novel materials of optical alignment layers that provide excellent orientation upon UV light exposure.

In particular, the present invention provides a method of inducing pretilt in the orientation of a liquid crystal medium adjacent the surface of the optical alignment layer, which method

(a) exposing the at least one optical alignment layer comprising anisotropic absorbing molecules and hydrophobic moieties to polarized light having a wavelength belonging to the absorption band of the anisotropic absorbing molecule so that the exposed anisotropic absorbing molecules are optical with respect to the polarization direction of the incident light; Inducing liquid crystal medium orientation of + and − angles along the surface of the alignment layer and inducing pretilt of Φ angle with respect to the surface of the optical alignment layer;

(b) applying a liquid crystal medium having an isotropic point to the optical alignment layer;

(c) heating the liquid crystal medium to a temperature above its isotropic point; And

(d) cooling the liquid crystal medium to a temperature below its isotropic point

It includes.

The invention also includes a liquid crystal display element derived from the method of the invention.

The present invention comprises two or more structural elements of the following formulas IV and V derived from at least one diaryl ketone tetracarboxylic dianhydride, at least one hydrophobic diamine and at least one alicyclic tetracarboxylic anhydride A polyimide composition for generating pretilt in the orientation of the liquid crystal medium, including copolyimide, is used.

(In the above formula,

Y is a divalent group selected from formulas II and III;

X ₂ is H, Cl, F, Br, R ₃ and R ₃ O- (where R ₃ is a C ₁ -C ₃ perfluorinated alkyl chain, a C ₁ -C ₃ partial fluorinated alkyl chain and C ₁ -C Independently selected from the group consisting of ₈ hydrocarbon chains;

m is 1 or 0;

P is a tetravalent organic group derived from an alicyclic tetracarboxylic dianhydride containing 4 or more carbon atoms, and at most one carbonyl group in the dianhydride is attached to any one carbon atom of the tetravalent group. )

Wherein Z is -S-, -O-, -SO _2- , -CH _2- , -C (CF ₃ ) _2- , -C (O)-, -CH ₂ CH _2- , -NR- ( Wherein R is independently a C ₁ -C ₄ hydrocarbon chain) and a covalent bond; X is R ₁ , -OR ₁ , -SR ₁ , -N (R ₂ ) -R ₁ , wherein R ¹ is a C ₄ -C ₂₀ perfluorinated alkyl chain, a C ₄ -C ₂₀ partial fluorinated alkyl chain, And C _{2 0} -C ₂₀ hydrocarbon chains independently, R ₂ is independently selected from H, C ₁ -C ₉ hydrocarbon chains and R ₁ ; X ₁ is independently selected from X and H.

1 is a cross-sectional view of a typical liquid crystal display cell of the present invention.

2 is an explanatory diagram of a pretilt angle Φ.

3 is a system used to expose an applied substrate to ultraviolet light.

4 is a schematic representation of a system used to expose a substrate coated with ultraviolet light from a UV lamp light source.

As used herein, the term "substrate" refers to the support structure of the alignment layer. The substrate may be any combination of solid laminates that provide a useful function for the final optical alignment layer or liquid crystal display device. For example, the substrate can be crystalline or amorphous silicon, glass, plastics, including polyesters, polyethylenes, and polyimides; Any combination of materials such as quartz, indium-tin-oxide, gold, silver, silicon dioxide, polyimide, silicon monoxide, antireflective coating, colored filter layer, polarizer and phase compensation film may be used. Indeed, some of these materials are deposited or applied onto base support structures such as glass or plastic.

As used herein, the term "orientation layer" refers to a layer of material on the substrate surface that controls the orientation of the liquid crystal layer without an external field. As used herein, the term "traditional alignment layer" refers to an alignment layer which only aligns the liquid crystal layer by other processing than optical means. For example, mechanically rubbed polyimides, evaporated silicon dioxide, and Langmuir-Blodgett films have all been known to orient liquid crystals.

The term "alignment of liquid crystal" as used herein means that the molecular long axis of the liquid crystal molecules has the desired local alignment direction or director. This director is the average direction of the entire liquid crystal molecule which can be quantified by order parameter or other measurement method known in the art. The orientation order parameter is usually represented by the following formula.

S = 1/2 〈3cos ² α-1〉

Where α is the angle between the director and the long axis of each molecule considered to be a symmetric cylinder. Square brackets indicate an average over the entire molecule. Order parameters range from 0 to 1.0. A value of 0 indicates that there is no long range liquid crystal alignment. A value of 1.0 indicates that the liquid crystal molecules are fully aligned along the director. Preferred order parameters by the method of the invention range from about 0.1 to 1.0.

The term "optical alignment layer" herein refers to an alignment layer containing anisotropic absorbing molecules that align the liquid crystal after exposure to polarized light. The optical alignment layer can be treated by conventional methods such as mechanical rubbing before and after exposure to polarized light. Anisotropic absorbing molecules of the optical alignment layer exhibit absorption characteristics with different values when measured along the axis in different directions. Anisotropic absorbing molecules exhibit absorption bands of about 150 nm to 2000 nm. The anisotropic absorbing molecules of the optical alignment layer are covalently bonded within the polymer backbone, covalently bonded to the polymer backbone as side chains, present in the polymer as an unbonded solute, or adsorbed onto the surface of a common alignment layer in adjacent liquid crystal layers as a solute. Can be formed.

Preferred optical alignment layers have a maximum absorbance of about 150-1600 nm. More preferred optical alignment layers have a maximum absorbance of about 150 nm to 800 nm. Most preferred optical alignment layers of the present invention have a maximum absorbance of 150 to 400 nm, in particular 300 to 400 nm.

Anisotropic absorbing molecules useful for the preparation of the optical alignment layer include dichroic aryl azo, di (aryl azo), tri (aryl azo), tetra (aryl azo), penta (aryl azo), anthraquinone, mercynin, methine, 2- Phenylazothiazole, 2-phenylazobenzthiazole, stilbene, 1,4-bis (2-phenylethenyl) benzene, 4,4'-bis (arylazo) stilbene, perylene and 4,8- Diamino-1,5-naphthoquinone dyes. Another useful anisotropic absorbing material is the liquid crystal bound dichroic dye described in US Pat. No. 5,389,285.

The preparation of the anisotropic absorbent material described above is described, for example, in US Pat. No. 4,565,424 to Huffman et al., US Pat. No. 4,401,369 to Jones et al., Cole, Jr. et al. US Pat. No. 4,122,027, US Pat. No. 4,667,020 to Etzbach et al., And US Pat. No. 5,389,285 to Shannon et al.

Another anisotropic absorbing molecule useful for preparing a colorless optical alignment layer is a diaryl ketone having a ketone residue or ketone derivative bonded to an aromatic ring. Specific kinds of such molecules useful for the optical alignment layer include substituted benzophenones, benzophenone imines, phenylhydrazones, and semicarbazones. Specific benzophenone derivatives preferred as the optical alignment layer of the method of the present invention include 4,4'-diaminobenzophenone, 4,4'-bis (trifluoromethyl) benzophenone, and 3,4'-bis (trifluoromethyl ) Benzophenone, and 3,3'-bis (trifluoromethyl) benzophenone. Also preferred are benzophenones and 4,4'-trifluoromethylbenzophenone imines derived from n-octadecylamine, 4-hexyloxyaniline and 4-octadecyloxyaniline. Benzophenone, 4,4'-bis (trifluoromethyl) benzophenone, 3,4'-bis (trifluoromethyl) benzophenone, 3,3'-bis (tri) derived from condensation with phenylhydrazine Phenylhydrazone of fluoromethyl) benzophenone; And benzophenone, 4,4'-bis (trifluoromethyl) benzophenone, 3,4'-bis (trifluoromethyl) benzo, derived from chemical reduction of the corresponding 2,4-dinitrophenylhydrozone Phenones and 2,4-diaminophenylhydrazone of 3,3'-bis (trifluoromethyl) benzophenone are also preferable as the optical alignment layer of the present invention.

Preferred anisotropic absorbing molecules of the optical alignment layer include arylazo, poly (arylazo), stilbenes and diaryl ketone derivatives. Arylazo, stilbene and diaryl ketone derivatives are the most preferred dyes for optical alignment layers having a maximum absorbance of about 150 to 400 nm. Poly (arylazo) dyes are most preferred for optical alignment layers having a maximum absorbance of about 400 to 800 nm. The most preferred poly (azo) dye is diazodiamine A, the most preferred stilbene dye is 4,4'-diaminostilbene B, and the most preferred arylazo dye is monoazodiamine C (Table 1). The preparation of dye A is described in US Pat. No. 5,389,285, the synthesis of dye C is described in the examples, and 4,4'-diaminostilbene is a dihydrochloride salt from Aldrich Chemical Co., Wisconsin. , Milwaukee).

Diaryl ketone tetracarboxylic dianhydrides are particularly useful and preferred as anisotropic absorbing molecules. Preferred diaryl ketone tetracarboxylic dianhydrides are described in more detail in the description of the following polyimide.

The optical alignment layer used in the method of the present invention also contains a hydrophobic moiety. "Hydrophobic moiety" refers to a functional group that imparts strong water immiscibility and strong surface tension to a material. Hydrophobic moieties usually, but not exclusively, covalently bond with a polymer that also acts as a matrix or carrier of anisotropic absorbing molecules forming an optical alignment layer. Most notable hydrophobic residues are fluorinated and partially fluorinated alkyl and long chain aliphatic hydrocarbons. Common hydrophobic moieties containing fluorinated and partially fluorinated alkyl chains include, for example, monovalent 1H, 1H-pentadecafluoro-1-octyloxy and 11H-eicosafluorodecanoyl groups, which are commercially available. Or can be easily obtained according to known synthesis methods. Common hydrophobic compounds containing long chain aliphatic hydrocarbons include monovalent hexadecyl, hexadecyloxy, octadecyl, and octadecyloxy groups and divalent hexadecylmethylene and octadecylmethylene groups.

Methods of introducing hydrophobic moieties into many polymeric materials are well known. Examples of polymers having hydrophobic moieties, useful as matrices in the optical alignment layer, include poly (methylmethacrylate) and poly (methylacrylate) air containing varying amounts of fluoroalkyl methacrylate and fluoroalkyl acrylate. Coalescing such as 1H, 1H, 11H-eicosafluorodecyl methacrylate.

Aromatic diamines substituted with hydrophobic residues are particularly useful and preferred as hydrophobic residues in the polyimide synthesis of the optical alignment layer. Preferred hydrophobic diamines are further described in the following polyimide.

Preferably, the anisotropic absorbing molecule and the hydrophobic moiety are covalently bonded to the polymer. For example, poly (amic acid), a precursor of polyimide, can be prepared by an anisotropic absorbing material covalently bonded to a poly (amic acid) polymer chain. This can usually be achieved by mixing dianhydrides and diamines, including anisotropic absorbing molecules, as one of the two reaction components. For example, 4,4'-diaminostilbene is an anisotropic absorbing molecule that can act as a reactive diamine in polyimide synthesis. 3,3 ', 4,4'-benzophenonetetracarboxylic anhydride is an anisotropic absorbing molecule that can act as a reactive dianhydride in polyimide synthesis. Diamine and dianhydride are polymerized in a solvent such as N-methylpyrrolidone or tetrahydrofuran to form a prepolymer solution which is then applied to a substrate and baked in an oven to form the final polyimide optical alignment layer Get

Alternatively, the optical alignment layer may have anisotropic absorbing molecules present as unbound solute dissolved in the polymer containing the hydrophobic moiety. These are called guest-host optical alignment layers. This alignment layer is produced by applying a thin layer organic material containing anisotropic absorbing molecules to a substrate. Typically, anisotropic absorbing molecules are dissolved in a solvent together with the polymeric material. The solution is then applied to the substrate using spin casting techniques. The coating is then baked in an oven to remove residual solvent and to carry out final curing.

Alternatively, the optical alignment layer is prepared by applying a conventional alignment layer such as hydrophobic polyimide to the substrate. Anisotropic absorbing molecules are dissolved in the liquid crystal medium to form a guest-host mixture. An optical alignment layer is formed when the guest-host mixture containing anisotropic absorbing molecules is contacted with a conventional alignment layer.

As another alternative manufacturing technique, the optical alignment layer can be produced by applying a conventional alignment layer such as a hydrophobic polyimide to a substrate, and the anisotropic absorbing molecule is dissolved in a solvent. When a solution containing anisotropic absorbing molecules is applied to a conventional alignment layer, an optical alignment layer is formed.

Preferred polymers in the optical alignment layer of the present invention are polyimide polymers. The preparation of polyimides is described in Wilson, "Polymers", D. Wilson, H. D. Stenzenberger, and P. M. Hergenrother Eds., Chapman and Hall, New York (1990). Typically, polyimides are prepared by condensing one equivalent of the diamine component with one equivalent of the dianhydride component in a polar solvent to obtain a poly (amic acid) prepolymer intermediate. Conventional solvents used in the condensation reaction include N-methyl-pyrrolidone (NMP), dimethylacetamide (DMAc), dimethylformamide (DMF), dimethyl sulfoxide (DMSO), butyl cellosolve, ethylcarbitol, γ -Butyrolactone. Poly (amic acid) is typically provided in a solution of 1 to 30% by weight. The condensation reaction is usually carried out at room temperature to 150 ° C. The prepolymer solution is applied to the desired substrate and thermoset at 180 to 300 ° C. to complete the imidization process. Alternatively, the poly (amic acid) prepolymer is chemically imidated by the addition of a dehydrating agent to form a polyimide polymer. Examples of chemical imidating agents are organic bases including organic anhydrides such as acetic anhydride and trifluoroacetic anhydride such as triethylamine and pyridine. Other chemical imidating agents include ethylchloroformate and triethylamine, thionyl chloride, oxalyl chloride, acetyl chloride and dicyclohexylcarbodiimide. Chemical imidization is carried out at room temperature to 150 ° C. Chemical imidization requires the resulting polyimide to be soluble in the solvent for further processing. To achieve solubility, polyimides often have to be specially prepared for chemical imidization. A chemically imidized polyimide solution is applied to the substrate and heated to remove the solvent, but does not require hot curing. Preferred compositions of the invention are chemically imidized polyimides.

Particularly useful in the process of the invention are polyimide polymers which are the condensation reaction products of hydrophobic diamines and dianhydrides. Preference is given to polyimide polymers which are polyimide homopolymers or polyimide copolymers of at least one tetracarboxylic dianhydride and at least one hydrophobic diamine, comprising at least one structural element of formula (I).

(In the above formula,

Y is a divalent group selected from formulas II and III;

M is a tetravalent organic group derived from said tetracarboxylic dianhydride containing two or more carbon atoms, and no more than two carbonyl groups in said dianhydride are attached to any one carbon atom of said tetravalent group)

<Formula II>

<Formula III>

Wherein Z is -S-, -O-, -SO _2- , -CH _2- , -C (CF ₃ ) _2- , -C (O)-, -CH ₂ CH _2- , -NR- ( Wherein R is C ₁ -C ₄ hydrocarbon chain) and a covalent bond; X is R ₁ , -OR ₁ , -SR ₁ , -N (R ₂ ) -R ₁ , wherein R ₁ is a C ₄ -C ₂₀ perfluorinated alkyl chain, a C ₄ -C ₂₀ partial fluorinated alkyl chain, And C _{2 0} -C ₂₀ hydrocarbon chains independently, R ₂ is independently selected from H, C ₁ -C ₉ hydrocarbon chains and R ₁ ; X ¹ is independently selected from X and H.

The diamines useful in the present invention that not only induce limited pretilt of the liquid crystal medium but also provide good orientation uniformity are listed in Table 2. Preferred hydrophobic diamines have an NH ₂ -Y-NH ₂ structure, wherein Y is as described above. Specific hydrophobic diamines preferred in the present invention include 4- (1H, 1H-pentadecafluoro-1-octyloxy) -1,3-benzenediamine (8) and 4- (1H, 1H, 11H-eicosafluoro- 1-undecyloxy) -1,3-benzenediamine (9). Specific preferred diamines having hydrocarbon chains include 4- (1-octadecyloxy) -1,3-benzenediamine (10), 4- (1-hexadecyl-1,3-benzenediamine) (11) and 2- (1-octadecyloxy) -1,4-benzenediamine (12).

Specific hydrophobic diamines useful in the present invention can be readily obtained by synthesis. The dinitro compounds corresponding to diamines (8) and (9) contain halogens from 1-halo-2,4-dinitrobenzene with 1H, 1H-pentadecafluoro-1-octanol and 1H, 1H, 11H-. It can be prepared by nucleophilic substitution with eicosafluoro-1-undecanol, respectively, and PCR Inbc. (Gainsville, FL 32602). These are described in Ichino, et el., In J. Poly. Sci., 28, 323 (1990) to chemically reduce to diamines to obtain diamines (8) and (9). The dinitro compounds corresponding to diamines (10) to (13) are prepared by alkylating 2,4-dinitrophenol or 2,5-dinitrophenol in dimethylformamide / sodium carbonate with brominated alkyl at 90 to 100 ° C. . The dinitro compound corresponding to diamine (14) is prepared by nitration of n-octylbenzene. Dinitro compounds corresponding to diamines (15) and (16) are prepared from 1-chloro-2,4-dinitrobenzene as described in US Pat. No. 4,973,429. The dinitro compound is reduced chemically with tin (II) chloride / ethanol or with the corresponding diamines (10) to (16) by catalyst with hydrogen and palladium / carbon.

Other amines that can be used with the hydrophobic diamines described above can be very broad. Specific examples include the trifluoromethyl substituted diamines (1) to (7) and lower hydrocarbon homologues (11), (13) and (14) in Table 2. Aromatic diamines that can be used include p-phenylenediamine, m-phenylenediamine, 2,5-diaminotoluene, 2,6-diaminotoluene, 4,4'-diaminobiphenyl, 3,3'-dimethyl -4,4'-diaminobiphenyl, 3,3'-dimethoxy-4,4'-diaminobiphenyl, diaminodiphenylmethane, diaminodiphenylether, 2,2-diaminodiphenylpropane , Bis (3,5-diethyl-4-aminophenyl) methane, diaminodiphenylsulfone, diaminonaphthalene, 1,4-bis (4-aminophenoxy) benzene, 1,4-bis (4-amino Phenyl) benzene, 9,10-bis (4-aminophenyl) anthracene, 1,3-bis (4-aminophenoxy) benzene, 4,4'-bis (4-aminophenoxy) diphenylsulfone, 2, 2-bis [4- (4-aminophenoxy) phenyl] propane, 2,2-bis (4-aminophenyl) hexafluoropropane and 2,2-bis [4- (4-aminophenoxy) phenyl] Hexafluoropropane; Alicyclic diamines include, for example, bis (4-aminocyclohexyl) methane; Aliphatic diamines include, for example, tetramethylenediamine and hexamethylene diamine. It is also possible to use diaminosiloxanes such as bis (3-aminopropyl) tetramethyldisiloxane. Such diamine can be used individually or in combination as 2 or more types of mixtures.

Other diamines preferred for the process of the invention and the polyimide compositions of the invention are diaminobenzophenones. Diaminobenzophenones are diaryl ketones and thus serve as another photoactive species in this process. With copolyimides comprising both diamino and dianhydride derivatives of diaryl ketones, higher concentrations of active chromophores can be achieved. Preferred diaminobenzophenones of the copolyimide composition of the present invention are 4,4'-diaminobenzophenone and 3,4'-diaminobenzophenone.

Preferably, the hydrophobic diamine comprises about 1.0 to 50 mol% of the diamine component, and most preferably the hydrophobic diamine comprises about 1.0 to 15 mol% of the diamine component. Adding more than about 50 mol% hydrophobic diamine to the diamine component tends to provide pretilts greater than 30 °.

In a preferred method of the invention, the polyimide polymer is a copolyimide further comprising at least one structural element of formula (Ia), wherein the ratio of structural elements of formula (I) and formula (I ') in the copolyimide is from about 1:99 to 99 : 1.

In the above formula, Y ₁ is a divalent organic group different from Y having two or more carbon atoms; M is as described above.

Tetracarboxylic dianhydrides useful for forming the polyimide of the present invention have the following structure.

In the above formula, M is a tetravalent organic group containing two or more carbon atoms, and two or less carbonyl groups of the dianhydride are attached to any one carbon atom of the tetravalent group.

Specific examples of the tetracarboxylic dianhydride component include aromatic dianhydrides (e.g., pyromellitic dianhydride, 2,3,6,7-naphthalenetetracarboxylic dianhydride, 1,2,5,6-naphthalene Tetracarboxylic dianhydride, 1,4,5,8-naphthalenetetracarboxylic dianhydride, 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride, 2,3,2', 3 '-Biphenyltetracarboxylic dianhydride, bis (3,4-dicarboxyphenyl) ether dianhydride, 3,3', 4,4'-benzophenonetetracarboxylic dianhydride, bis (3,4- Dicarboxyphenyl) diphenylsulfone dianhydride, bis (3,4-dicarboxyphenyl) methane dianhydride, 2,2-bis (3,4-dicarboxyphenyl) propane dianhydride, 1,1,1,3, 3,3-hexafluoro-2,2-bis (3,4-dicarboxyphenyl) propane dianhydride, bis (3,4-dicarboxyphenyl) dimethylsilane dianhydride, 2,3,4,5-pyridine Tetracarboxylic dianhydride); Alicyclic tetracarboxylic dianhydrides (eg, 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2,3,4-butanetetracarboxylic dianhydride, 1,2, 3,4-cyclopentanetetracarboxylic dianhydride, 1,2,4,5-cyclohexanetetracarboxylic dianhydride, 2,3,5-tricarboxycyclophenylacetic dianhydride and 3,4-dicarboxyl -1,2,3,4-tetrahydro-1-naphthalenesuccinic dianhydride); And acid and acid chloride derivatives thereof.

Diaryl ketone tetracarboxylic dianhydride that is particularly useful in the present invention is a compound having the structure:

Wherein X ₂ is H, Cl, F, Br, R ₃ and R ₃ O, wherein R ₃ is a C ₁ -C ₃ perfluorinated alkyl chain, a C ₁ -C ₃ partial fluorinated alkyl chain and C Independently selected from ₁ -C ₈ hydrocarbon chain); m is 1 or 0; Z is -S-, -O-, -SO _2- , -CH _2- , -C (CF ₃ ) _2- , -C (O), -CH ₂ CH _2- , -NR- (where R is C ₁ -C ₄ hydrocarbon chain) and a covalent bond. More preferred diaryl ketones include 3,3 ', 4,4'-benzophenonetetracarboxylic dianhydride (D1) and 2,2'-dichloro-4,4', 5,5'-benzophenone tetracarboxyl There is acid dianhydride (D2). Most preferred benzophenone tetracarboxylic dianhydride in the present invention is 3,3 ', 4,4'-benzophenone tetracarboxylic dianhydride (D1). Other related photosensitive diaryl ketone dianhydrides described in US Pat. No. 4,698,295 to Pfeifer et el., And incorporated herein by reference, are useful replacements for benzophenonetetracarboxylic dianhydride in the process of the present invention. .

Specific benzophenonetetracarboxylic dianhydrides preferred in the present invention can be easily obtained by commercial products or by synthesis. For example, 3,3 ', 4,4'-benzophenonetetracarboxylic dianhydride (D1) is commercially available from Aldrich Chemical (W1 53233, Milwaukee, W. St. Foul Avenue, 1001). 2,2'-dichloro-4,4 ', 5,5'-benzophenone tetracarboxylic dianhydride was prepared by 4-chloro-o-xylene by Friedel-Crafts acylation with oxalyl chloride. From 2,2'-dichloro-4,4 ', 5,5'-tetramethylbenzophenone, which is then oxidized with nitric acid, and the resulting tetracarboxylic acid is obtained from Faligno, et al. J. Poly. Sci. 1992, 30, 1433, it can be obtained by dehydration.

"Alcyclic tetracarboxylic dianhydride" refers to a dianhydride containing some or all of a saturated carbocyclic ring. Alicyclic tetracarboxylic dianhydrides impart useful solubility properties to the polyimide comprising them. Alicyclic tetracarboxylic dianhydrides suitable for the present invention are listed in Table 3. Preferred alicyclic dianhydrides include 5- (2,5-dioxotetrahydro) -3-methyl-3-cyclohexene-1,2-dicarboxylic anhydride (D3), 2,3,5-tricarboxycyclo Pentanacetic dianhydride (D4), cyclobutanetetracarboxylic dianhydride (D5) and 1,2,3,4-butanetetracarboxylic dianhydride (D7).

5- (2,5-dioxotetrahydro) -3-methyl-3-cyclohexene-1,2-dicarboxylic acid anhydride (D3) is commercially available from Chriskev Co. Inc. 1,2,3,4-cyclobutanetetracarboxylic acid is commercially available from Aldrich Chemical, which can be easily converted to an dianhydride using oxalyl chloride. 2,3,5-tricarboxycyclopentanoacetic dianhydride (D4) is obtained through the synthesis of oxidizing dicyclopentadiene to nitric acid, as described in British Patent No. 1 518 322 (1976) to Henssion et al. Can be. The synthesis of 1,2,3,4-cyclobutanetetracarboxylic dianhydride (D5) is described by Moore et al., Chem. Mat., 1989, 1, 163. 1,2,3,4-butanetetracarboxylic dianhydride (D7) can be obtained by treating the corresponding tetracarboxylic acid (made by Aldrich) with acetic anhydride. 5,5 '-(1,1,3,3-tetramethyl-1,3-disiloxanediyl) -bis- (norbornane-2,3, -dicarboxylic anhydride) (D9) is Liang It can be obtained by hydrosilane formation reaction with anhydrous 5-norbornene-2,3-dicarboxylic acid with 1,1,3,3-tetramethyldisiloxane as described in (Ryang) U.S. Patent 4,381,396. have. Bicyclo [2.2.1] heptanetetracarboxylic acid 2,3: 5,6-anhydride (D10) is a bicyclo [as described in Matsumoto et el., In Macromolecules 1995, 28, 5684]. 2.2.1] from the hept-5-ene-2,3-dicarboxylic acid anhydride. Bicyclo [2.2.2] oct-7-entetracarboxylic acid 2,3: 5,6-anhydride (D11) is described in Itamura et al., Itamura et el., In Macromolecules 1993, 26, 3490. As described above, it can be synthesized from 4-cyclohexene-1,2-dicarboxylic acid anhydride.

In polyimide preparation of the optical alignment layer, the molar ratio of diamine to dianhydride is usually 1: 1 but can vary within 0.8: 1 to 1:12. The preferred ratio of diamine to dianhydride is within 0.98: 1 to 1: 1.02. Most preferably, the ratio of diamine to dianhydride is 1: 1.

Another embodiment of the present invention provides a pretilt in the orientation of the liquid crystal medium, comprising at least one diaryl ketone tetracarboxylic dianhydride, at least one hydrophobic diamine, and at least one alicyclic tetracarboxylic anhydride. A novel polyimide composition comprising at least two structural elements of the formulas IV and V, derived from the diamine component and the dianhydride component, for the production.

<Formula IV>

In the above formula,

Y is a divalent group selected from formulas II and III;

X ₂ is H, Cl, F, Br, R ₃ and R ₃ O- (where R ₃ is a C ₁ -C ₃ perfluorinated alkyl chain, a C ₁ -C ₃ partial fluorinated alkyl chain and C ₁ -C independently selected from ₈ hydrocarbon chain) with independently selected from the group consisting of;

m is 1 or 0;

P is a tetravalent organic group derived from the alicyclic tetracarboxylic dianhydride containing four or more carbon atoms, and at most one carbonyl group in the dianhydride is attached to any one carbon atom of the tetravalent group. being)

<Formula II>

<Formula III>

[Wherein, Z is -S-, -O-, -SO _2- , -CH _2- , -C (CF ₃ ) _2- , -C (O)-, -CH ₂ CH _2- , -NR- Wherein R is a C ₁ -C ₄ hydrocarbon chain and is independently selected from the group consisting of covalent bonds; X is R ₁ , -OR ₁ , -SR ₁ , -N (R ₂ ) -R ₁ , wherein R ₁ is a C ₄ -C ₂₀ perfluorinated alkyl chain, a C ₄ -C ₂₀ partial fluorinated alkyl chain, And C _{2 0} -C ₂₀ hydrocarbon chains independently, R ₂ is independently selected from H, C ₁ -C ₉ hydrocarbon chains and R ₁ ; X ₁ is independently selected from X and H. Most preferred are compositions wherein the copolyimide comprises the structural elements of Formulas IV and V in a ratio of 1:10 to 99: 1.

Another preferred polyimide composition is a composition further comprising one or more structural elements of Formulas VII and VIII, further comprising one or more diaminobenzophenones.

In the above formula, Z, X ₂ , P and m are as described above.

Another embodiment of the present invention provides two or more structural elements of formulas IV and VII, derived from one or more diaryl ketone tetracarboxylic dianhydrides, one or more hydrophobic diamines and one or more diaminobenzophenones. A polyimide composition derived from a diamine component and a dianhydride component for causing pretilt in the orientation of the liquid crystal medium, including copolyimide comprising.

<Formula IV>

<Formula VII>

In the above formula, Y, Z, X, X ₁ , X ₂ and m are as described above.

Another embodiment of the present invention comprises two or more structural elements of the following formulas V and VIII derived from one or more alicyclic tetracarboxylic dianhydrides, one or more hydrophobic diamines and one or more diaminobenzophenones It is a polyimide composition derived from a diamine component and a dianhydride component for generating pretilt in the orientation of a liquid-crystal medium containing copolyimide.

<Formula V>

<Formula VIII>

In the above formula, Y, Z, X, X ₁ , X ₂ , P and m are as described above.

Another embodiment of the invention is a structure of one or more of the following formulas IV and IVa derived from one or more diaryl ketone tetracarboxylic dianhydrides, one or more hydrophobic diamines and one or more diamines derived from Y ₂ A polyimide composition derived from a diamine component and a dianhydride component for causing pretilt in the orientation of the liquid crystal medium, including copolyimide comprising urea.

<Formula IV>

<Formula IVa>

Wherein Y, Z, X, X ₁ , X ₂ , P and m are as described above, and Y ₂ is a divalent group selected from the following formulas IIa and IIIa.

In the formula, X ₃ is C ₁ -C ₃ perfluorinated alkyl chain, partially fluorinated alkyl chain or are independently selected from -OCF _3; X ₄ is independently selected from X ₃ and H.

Of all the preferred compositions described above, it is usually preferred to have a particular functionality. Most preferred diaryl ketone tetracarboxylic anhydride is 3,3 ', 4,4'-benzophenonetetracarboxylic anhydride. Preferred alicyclic tetracarboxylic dianhydrides include 5- (2,5-dioxotetrahydro) -3-methyl-3-cyclohexene-1,2-dicarboxylic anhydride, 2,3,5-tricarboxy Cyclopentaneacetic anhydride, 1,2,3,4-butanetetracarboxylic anhydride and cyclobutanetetracarboxylic anhydride. Most preferably 5- (2,5-dioxotetrahydro) -3-methyl-3-cyclohexene-1,2-dicarboxylic anhydride, 2,3,5-tricarboxycyclopentaneacetic anhydride and 1 , 2,3,4-butanetetracarboxylic anhydride, which provide useful resolutions for polyimides. Most preferred hydrophobic diamines are 4- (1H, 1H-pentadecafluoro-1-octyloxy) -1,3-benzenediamine, 4- (1H, 1H, 11H-eicosafluoro-1-undecyloxy) -1,3-benzenediamine, 4- (1-octadecyloxy) -1,3-benzenediamine, 4- (1-hexadecyl) -1,3-benzenediamine and 2- (1-octadecyloxy C) -1,4-benzenediamine. 4,4'-diaminobenzophenone is the most preferred diaminobenzophenone. Most preferably, the Y ₂ groups are 2- (trifluoromethyl) -1,4-benzenediamine (1), 5- (trifluoromethyl) -1,3-benzenediamine (2), 2,2 ' With bis (trifluoromethyl) benzidene (7), 2,2'-bis (trifluoromethoxy) benzidene (6) and 3,3'-bis (trifluoromethyl) benzidene (5) Derived from a diamine selected from the group consisting of.

Preferably, the hydrophobic diamine comprises 1.0 to 50 mol% of the diamine component, and most preferably the hydrophobic diamine comprises 1.0 to 15 mol% of the diamine component. As will be readily appreciated by those skilled in the art, variations may be made in carrying out many embodiments of the present invention. Most fundamentally, as the necessary anisotropic absorbing molecules and hydrophobic molecules impart the desired pretilt at any concentration, the greater the concentration, the greater the effective angle. Similarly, there are variations in the performance represented by certain anisotropic absorbing molecules and hydrophobic molecules. For example, despite the structural identity among the diamines described in Table 2, diamine 10 showed superior performance over diamine 12, and diamine 8 was usually found to be particularly satisfactory.

The compositions of the present invention provide high resolution and optical orientation performance (limited pretilt, low energy threshold, high quality orientation and transmission to visible light), which is very desirable in the fabrication of liquid crystal display devices.

In order to produce the optical alignment layer of the present invention, a polymer solution of a poly (amic acid) solution or a preimidized polyimide solution is applied to a desired substrate. Coating is usually carried out to have 2 to 30% by weight solids. Any conventional method may be used for substrate application, including brushing, spraying, spin-casting, dipping or printing. The applied substrate is usually heated in an oven under an inert atmosphere, for example nitrogen or argon, at elevated temperatures, preferably not more than 300 ° C., preferably at most 180 ° C. for 1-12 hours, preferably up to 2 hours. The heating process can be used to remove the solvent carrier and further cure the polymer. For example, a poly (amic acid) film is cured with heat to produce a polyimide film.

The optical alignment layer is exposed to polarized light to induce alignment of the liquid crystal. The term “polarized light” means light that is elliptically polarized so that light is more polarized along its uniaxial axis (called the major) as compared to its orthogonal axis (called the minor). Preferred polarizations are linear polarizations with little or no polarization components along the longitudinal axis, usually polarized along one axis (major axis). The polarized light in the present invention has one or more wavelengths of about 150 to 2000 nm and preferably about 150 to 1600 nm and more preferably about 150 to 800 nm. Most preferably at least one wavelength of about 150 to 400 m, in particular about 300 to 400 nm. Preferred light sources are lasers, for example argon, helium neon, or helium cadmium. Other preferred light sources include mercury arc, xenon lamps, deuterium and quartz tungsten halogen lamps, and black light together with polarizers. Useful polarizers for generating polarized light from non-polarized light sources include interference polarizers, absorbing polarizers, and Brewster reflections made from dielectric stacks. When using low power lasers, or when aligning small alignment regions, it may be necessary to focus the light rays on the optical alignment layer.

Another polarization source is light from mercury arc, xenon lamps, deuterium and quartz tungsten halogen lamps, or black light that is unpolarized at the light source but is incident at an oblique angle to the optical alignment layer. For non-polarized incidence of inclination angle at the interface, the inclination of the incidence angle is due to non-polarization separated by a combination of three linearly polarized light (see, for example, Wood, Physical Optics, 3rd Ed. Optical Socciety of America, Washington DC, 1988). Similarly, another polarization source is circularly polarized light incident on the optical alignment layer at an oblique angle.

Inclined incidence mainly means having an incident light direction at any other angle with respect to the vertical line of the substrate plane. Inclined incidence and normal incidence are not limited to collimated light. For example, light focused in a conical light direction that is symmetric about the vertical line of the substrate is also considered normal incidence to the substrate. However, the same light focused in a conical light direction that is symmetric about an axis that is at an angle different from the vertical line of the substrate will be considered oblique incidence.

The term "exposure" means applying polarization to all or a portion of the optical alignment layer. The light can be fixed or rotated. The exposure can be in one step, continuously, in a scanning manner or in another method. The exposure time varies widely depending on the material used, and may range from less than 1 msec to more than 1 hour. The exposure can be performed before or after contacting the optical alignment layer (s) with the liquid crystal medium. Exposure can be achieved by linearly polarized light transmitted through one or more masks with one pattern or linearly polarized lines scanned in one pattern. The exposure may also be performed using interference of interfering optical lines forming the pattern, that is, crossed contrast lines.

Exposure energy conditions are determined in accordance with the composition and processing method of the optical alignment layer before and during the exposure. For example, materials with high glass transition temperatures may have high energy density requirements for optical orientation. In contrast, a material system designed to have a low glass transition temperature prior to exposure can have lower energy density conditions. The preferred exposure energy range is about 0.001 to 2000 J / cm 2. More preferably about 0.001 to 100 J / cm 2, most preferably about 0.001 to 5 J / cm 2. The lower the exposure energy, the more useful the large-scale manufacture of the optical alignment layer and the liquid crystal display device. In addition, low exposure energy minimizes the risk of damage to other materials on the substrate.

The efficiency of the alignment process, and the required exposure energy, can be further influenced by heating beyond the light energy inherent in the "exposure" step. Further heating during the exposure step can be carried out by conduction, convection or radiant heat or by exposure to unpolarized light. Further heating can increase the mobility of the molecules during exposure and improve the alignment quality of the optical alignment layer. Further heating is not a prerequisite for the process of the invention, but can provide beneficial results.

In a preferable exposure method, one or more optical alignment layers are exposed to polarized light at an oblique incident angle. With this exposure method, the liquid crystal medium has a pretilt that is stable to heat determined by polarization in the oblique incident angle direction as described below, without a flow action.

In addition, the exposure is composed of two or more exposure steps, and conditions such as the incident angle, the polarization position, the energy density, and the wavelength of each step vary. At least one step should include exposure to linearly polarized light. In addition, the exposure can be performed in an area much smaller than the substrate size to a size comparable to the overall substrate size.

Another preferred exposure method includes exposing at least one optical alignment layer to polarized light at an oblique angle of incidence and exposing the same optical alignment layer to polarized light at a second angle of incidence. In this multi-step process, the direction of linear polarization can remain the same or change in each exposure step. In a preferred process, the exposure to the oblique incident angle and the exposure to the second incident angle may be performed with polarizations in different directions.

All multi-step exposures described herein can be performed simultaneously or sequentially. One example of simultaneous exposure is exposure to an unpolarized oblique incidence angle, which is a combination of three linearly polarized light. Another example of simultaneous exposure is exposure to polarized light at an oblique incidence angle in an arbitrary direction different from 90 ° with respect to the plane of incidence. A third example of simultaneous exposure is to expose two or more polarization lines simultaneously in two or more directions of polarization and two or more angles of incidence.

Preferred double exposure methods include the following two steps.

(a) exposing the at least one optical alignment layer to polarized light at a normal angle of incidence, and

(b) exposing the optical alignment layer to polarized light at an oblique angle of incidence.

Another preferred double exposure method includes the following two steps.

(a) exposing the optical alignment layer to first direction linearly polarized light of incident light, and

(b) exposing the optical alignment layer to second direction linearly polarized light of incident light.

Another preferred double exposure method includes the following two steps.

(a) exposing the optical alignment layer to first direction linearly polarized light of incident light, and

(b) exposing the optical alignment layer to the second direction linearly polarized light of the incident light at an oblique incident angle.

Nematic liquid crystal materials, ferroelectric liquid crystal materials and the like are suitable as liquid crystal materials used for liquid crystal display devices. Liquid crystals useful in the present invention described herein include the liquid crystals described in US Pat. No. 5,032,009 and ZLI-5079, ZLI-5080, ZLI-5081, ZLI-5092, available from EM Industries, Hawthorne, NY. There are novel perfluorinated liquid crystals exemplified by ZLI-4792, ZLI-1828, MLC-2016, MLC-2019, MLC-6252 and MLC-6043. Also useful are guest-host compositions made with all types of liquid crystal and anisotropic absorbing dyes as described in US Pat. No. 5,032,009. Also useful in the present invention are the nematic and ferroelectric liquid crystals disclosed in US Pat. No. 5,447,759 entitled "Liquid Crystal Alignment Films and Liquid Crystal Display Devices," and incorporated herein by reference.

Often, chiral dopants are added to such liquid crystals to induce a one-way twist in the liquid crystal medium. A chiral doping agent in the left-right direction can be used. Typical examples are ZLI-811, S-1011 and R-1011, all from EM Industries.

Other liquid crystals useful in the present invention include polymer liquid crystals described in US Pat. No. 5,073,294 and liquid crystal difunctional methacrylate and acrylate monomers described in US Pat. No. 4,892,392. Both patents are incorporated herein by reference.

Other liquid crystals useful in the present invention are the liquid crystal polymers described in US Pat. No. 5,382,548, which is incorporated herein by reference. These polyester and polyurethane liquid crystal polymers have a low rotational viscosity between their glass transition temperature (T _g ) and their isotropic transition temperature (T _ni ) and readily respond to surface orientation strengths.

Preferred liquid crystals for the present invention include nematic liquid crystals, ferroelectric liquid crystals, high molecular nematic liquid crystals and nematic liquid crystal polymers. Particularly preferred liquid crystals for the present invention are nematic liquid crystals and polymer nematic liquid crystals. Specific types of preferred nematic liquid crystals include 4-cyano-4'-alkylbiphenyl, 4-alkyl- (4'-cyanophenyl) cyclohexane and ZLI- commercially available from EM Industries, Houghton, NY. And perfluorinated liquid crystal mixtures selected from the group of 5079, ZLI-5080, ZLI-5081, ZLI-5092, ZLI-4792, ZLI-1828, MLC-2016, MLC-2019, MLC-6252 and MLC-6043.

Applying the liquid crystal medium to the optical alignment layer may be performed by capillary filling in the cell, casting the liquid crystal medium to the optical alignment layer, laminating a preformed liquid crystal film to the optical alignment layer, or by other methods. . Preferred methods are capillary filling the cell or casting the liquid crystal medium in the optical alignment layer.

The cell can be made using two coated substrates that provide a sandwiched layer of liquid crystal medium. The pair of substrates may all contain an optical alignment layer, or a conventional alignment layer (eg, mechanically buffed) may be used as the second alignment layer comprising the same or different polymers. In addition, the optical alignment layer may be further processed by conventional orientation techniques such as mechanical buffing before and after the exposure step.

After the exposure step and the application of the liquid crystal medium, heating of the liquid crystal medium and cooling of the liquid crystal medium are performed. In this specification, heating and cooling steps are referred to as heat-cooling circulation.

"Heating" means the application of thermal energy to a liquid crystal from a common heat source. Thermal energy sources include radiant heaters, electric heaters, infrared lamps and conduction ovens. The liquid crystal medium is sufficiently heated to raise the medium temperature above the isotropic point. Isotropic point refers to the liquid crystal-isotropic transition, ie the temperature at which the medium transforms into a random isotropic liquid in a regular phase. Heating is carried out in a continuous step or at a constant rate of increase. Preferably, the heating is carried out at a temperature above about 0.01 to 60 ° C. of the isotropic point of the medium, in particular for about 1 second to 8 hours. Most preferably, the medium is heated for 1 minute to 2 hours at a temperature above about 1 to 50 ° C. of the isotropic point of the medium.

"Cooling" means the removal of thermal energy from the heated liquid crystal medium by conventional means. Conventional methods remove the heat energy source and allow the medium to equilibrate with room temperature; Contacting the medium with a colder medium, such as a water bath, to stop the reaction of the medium; Or gradually reducing the amount of thermal energy introduced into the medium. The liquid crystal medium is cooled to lower the temperature of the liquid crystal medium below the isotropic point. Cooling can be carried out in a continuous stage or at a constant rate. Preferably cooling is carried out at a constant or variable rate of about 1000 to 0.01 ° C./min. Most preferably cooling is carried out for about 1 second to 8 hours at a constant or variable rate of about 100 to 0.1 ° C./minute.

The method of the present invention can be used to manufacture the novel liquid crystal display device of the present invention. The liquid crystal display element of this invention consists of an electrode substrate, a voltage application apparatus, and a liquid crystal material which have one or more optical alignment layers of this invention.

1 illustrates a typical liquid crystal display device comprising a transparent electrode 2 of ITO (indium-tin-oxide) or tin oxide on a substrate 1 and an optical alignment layer 3 of the present invention formed thereon. The optical alignment layer is exposed to the polarization of the wavelength or wavelengths in the absorption band of the anisotropic absorbing molecule. The spacer 4 serving as the sealing resin is sandwiched between the pair of optical alignment layers 3. The liquid crystal 5 is added to the cell by capillary type, and the cell is sealed to prepare a liquid crystal display element. The substrate 1 includes a top coat film, for example, an insulating film, a colored filter, a colored filter top coat layer, a laminated polarizing film, and the like. Both these coatings and films are considered part of the substrate 1. In addition, active elements such as thin film transistors and nonlinear resistance elements can be formed on the substrate 1. Such an electrode, an undercoat layer, a top coat layer, etc. are the usual structures of a liquid crystal display element, and can be used for the display element of this invention. Thus, using the formed electrode substrate, a liquid crystal display element cell is manufactured, and a liquid crystal material is charged in a cell space to produce a liquid crystal display element with a voltage applying device.

The exposed anisotropic absorbing molecules induce the orientation of the liquid crystal medium at + and −θ angles along the plane of the optical alignment layer with respect to the polarization direction of the incident light beam. Furthermore, in the presence of hydrophobic residues, the exposed anisotropic absorbing molecules induce a pretilt of Φ angle with respect to the plane of the optical alignment layer.

Those skilled in the art will appreciate that the method of the present invention can control the orientation of the liquid crystal medium in the desired direction within the plane of the optical alignment layer by adjusting the conditions of polarized light exposure. Preferably, the liquid crystal medium is oriented at + and −θ angles, where θ is approximately 90 ° with respect to the polarization direction.

Pretilt is an important characteristic in the operating performance of most liquid crystal display devices. 2 illustrates the pretilt angle Φ. The liquid crystal director 6 is a direction of liquid crystal molecules close to the alignment of the optical alignment layer 3. "Pretilt" is a plane defined by a vertical line with respect to the substrate, and represents the angle with respect to the optical alignment layer 3 made by the liquid crystal director 6 and the projection angle of the local liquid crystal director with respect to the alignment layer. As depicted in FIG. 2, the pretilt angle Φ can range from 0 to 180 degrees. Only one substrate is shown for clarity. When the φ angle is 0 or 180 °, the orientation may appear as a uniform or planar orientation. When the angle Φ is 90 °, the orientation can be said to be homeotropic or vertical orientation. For Φ angles in the range of greater than 0 ° and less than 45 ° and less than 180 ° and 135 ° or more, the orientation exhibits almost uniform or planar orientation. In the case of Φ angles in the range of greater than 45 ° but less than 135 °, excluding 135 °, a homeotropic or vertical orientation is indicated.

Those skilled in the art will appreciate that the pretilt angle of 0 to 90 degrees is equal to the pretilt size of 180 to 90 degrees and the opposite direction is also the same. Pretilts preferred in the process of the invention range from 1 to 30 degrees and 179 to 150 degrees. Most preferred pretilts range from 2 to 15 degrees and 178 to 165 degrees.

Conventional methods for assessing pretilt are described by Bauer et al., Phys. Lett., (1976) 56A, 142] is a direct measurement of pretilt in planar oriented or twisted nematic cells using the crystal rotation method. The method assumes that the pretilt of the entire thickness of the liquid crystal layer is constant. Thus, the method provides an average value of pretilt. Those skilled in the art have found that the measurement technique requires the construction of non-parallel or non-skewed nematic cells that must ensure the same pretilt throughout the cell thickness. In one example, the following twisted nematic cells with non-oblique model alignment layers were used to evaluate the pretilt.

In some cases, the flow effect achieved while applying the liquid crystal medium to the optical alignment layer appears to control and determine the pretilt direction without the heat-cooling cycle. However, when carrying out the heat-cooling circulation according to the preferred embodiment of the present invention, the fluidity induces the pretilt direction, and the loss due to the flow disappears, thereby obtaining a thermally stable pretilt direction. The direction of the thermally stable pretilt is determined by the direction of the oblique incidence angle of polarization in the exposure step. The resulting oriented liquid crystal medium has a better uniformity than the liquid crystal medium obtained without the heat-cooling circulation.

In addition, the pretilt size is affected by the heat-cooling cycle of the complete liquid crystal device. An exposure period of heating higher than the isotropic transition of the liquid crystal medium in the device reduces the pretilt size. It is actually stabilized at a value less than the initial pretilt value. By varying the time at elevated temperature before cooling the sample, the pretilt size can be varied between the initial and minimum values. In addition, the type of cooling cycle can affect the pretilt size. When cooling was slowly carried out from an elevated temperature above the isotropic point to below the isotropic transition, it was observed that the pretilt size was smaller than that of the fast cooling (quenching). As a result of this, the pretilt size can be varied within its initial to minimum value by reducing the cooling rate. The size of the pretilt determined by the heat-cool cycle is stable at room temperature.

Although the present invention has been described in the following examples, it is not intended to be limited thereto. In the examples of the present invention, some hydrophobic diamines prepared synthetically were used.

Hydrophobic diamine (10) is prepared by the following method.

A mixture of 2,4-dinitrophenol (85% by weight, 6.72 g, 31 mmol), octadecyl bromide (20.7 g, 62 mmol), sodium carbonate (6.57 g, 62 mmol) and dimethylformamide (31 mL) was prepared. Heated at 22 ° C. under nitrogen atmosphere for 22 h. The mixture was cooled, diluted with water (200 mL), acidified with 10N hydrochloric acid (50 mL) and extracted with ether. The extract was washed with water and brine and dried over magnesium sulfate. The solvent was removed and the solid was recrystallized to give 1-octadecyloxy-2,4-dinitrobenzene (10.7 g, 79%; melting point 63.5-64.0 ° C).

A mixture of 1-octadecyloxy-2,4-dinitrobenzene (3.99 g, 9.15 mmol), tin (II) chloride dihydrate (23.93 g, 106 mmol) and anhydrous ethanol (40 mL) was stirred at 70 ° C. for 5 hours. Heated during. The cooled reaction mixture was poured onto ice and basified with concentrated aqueous sodium bicarbonate solution. The mixture was extracted with diethyl ether and the extract was dried over magnesium sulfate. The solvent was removed and the product was purified by chromatography (silica gel) to give diamine 10 (0.58 g, 17%; melting point 82.1-83.0 ° C).

Hydrophobic diamine (12) was prepared by the following method.

A mixture of 1-octadecyloxy-2,5-dinitrobenzene (6.87 g, 15.7 mmol), tin (II) chloride dihydrate (35.5 g, 157.3 mmol) and anhydrous ethanol (70 mL) was stirred at 70 ° C. for 5 hours. Heated during. The cooled reaction mixture was poured into ice and basified with concentrated aqueous potassium hydroxide solution. The mixture was extracted with diethyl ether and the extract was dried over magnesium sulfate. The solvent was removed and the product was purified by chromatography (silica gel) to give diamine 12 (5.2 g, 88%; melting point 74.0-74.5 ° C).

Hydrophobic diamine 16 was prepared by the following method.

1-chloro-2,4-dinitrobenzene (from Aldrich Chemical, 2.02 g, 10 mmol), sodium carbonate (1.27 g, 12 mmol), dioctadecylamine (from Palz & Bauer, 6.26 g, 12 mmol) ) And dry dimethylformamide (10 ml) mixture was heated at 80-90 ° C. under nitrogen atmosphere for 1 hour. The cooled mixture was diluted with water and extracted with ether. The extract was washed with water and dried over magnesium sulfate. The solvent was removed and the solid was recrystallized to give N, N-dioctadecyl-2,4-dinitrobenzeneamine (6.0 g, 87%; melting point 55.5-57.5 ° C).

Paring a mixture of N, N-dioctadecyl-2,4-dinitrobenzeneamine (11.8 g, 17.2 mmol), 5% palladium on carbon (1.8 g, 50% water) and tetrahydrofuran (180 g) Hydrogenated at 55 psi and room temperature for 7 hours in Parr shaker. The mixture was filtered through celite and the solvent was removed to give a solid. The solid was recrystallized from ethanol to give diamine 16 (7.47 g, 68%; melting point 41.5-44.0 ° C.).

<Example 1>

This example describes a method of inducing pretilt in the orientation of a liquid crystal medium containing the novel composition of the present invention.

4,4'-diaminobenzophenone (100.8 mg, 0.475 mmol) and 4- (1H, 1H-pentadecafluoro-1-octyloxy) -1,3-benzene in γ-butyrolactone (1.39 g) Di (8) (12.7 mg, 0.025 mmol) solution in 5- (2,5-dioxotetrahydro) -3-methyl-3-cyclohexene-1,2-dicarboxylic acid anhydride (D3) (132.1 mg , 0.5 mmol) were added all at once. The mixture was stirred at rt for 16 h under a nitrogen atmosphere. Acetic anhydride solution (0.142 mL, 1.5 mmol) in γ-butylactone (1.0 g) and triethylamine (0.21 mL, 1.5 mmol) were added successively and the solution was heated at 120 ° C. for 3 hours. The solution was cooled and diluted to 3% by weight with γ-butylactone (5.44 g) to obtain a polymer solution for spin casting.

Rotational application of two 2.29 cm (0.9 inch) x 3.05 cm (1.2 inch) x 1 mm thick borosilicate glass substrates with a transparent indium-tin-oxide (ITO) electrode coating (Donelli, Mich., Holland) And an optical alignment layer was obtained by curing with a polyimide composition. Spin coating could be obtained by filtering the solution directly onto a transparent ITO glass substrate surface through a 0.45 μm Teflon filtration membrane. The applied ITO glass substrate was then spun at 2500 RPM for 1 minute to produce a uniform thin film. The resulting thin film was cured at 80 ° C. under nitrogen for 0.25 hours and then at 180 ° C. for 1 hour.

The applied substrate was exposed to ultraviolet polarized light using the apparatus shown schematically in FIG. 3. In this experiment, each coated substrate 7 was installed in a translation stage of XY two axes (indicated by the double arrows in Fig. 3) so that the coated surface faces the incident laser beam. Innova 400 (Coherent Inc., Santa Clara, Calif.) Laser 9 was adjusted to fire with ultraviolet light having a wavelength in the range from 308 to 336 nm. The mirror 11 directs light to a 5 cm focal length cylindrical lens 12 focused with 1 cm incident light on a line (1 cm x 200 µm) on each applied substrate 7. The applied substrate was moved along the Y direction at a constant speed of 3.0 mm / second and then moved in the X direction. This was repeated until the applied substrate was completely exposed. The incident light output was 0.25 W, and the ultraviolet light was polarized along (10).

The twisted nematic liquid crystal cell consisted of two exposed coating substrates. 6 micron glass fiber spacers (EM Industries, Houghton, NY) were mixed with the epoxy and the epoxy mixture was placed at the edge of the coated surface on the exposed substrate. The second exposed substrate was placed on top of the first substrate so that the alignment layers faced each other and the orientation directions of each back side were perpendicular to each other. The substrates were pressed to a 6 μm space using a clamp and the fiber spacer / epoxy mixture was cured for 5 minutes. The two spaces on the opposite side of the cell were left unsealed so that the liquid crystal could fill the cell along the bisector between the orientation directions of the substrates. The cell was placed under reduced pressure, followed by one unsealed opening on the cell, followed by a ZLI4792 nematic liquid crystal (EM Industries, NY, Houghton) with 0.1% ZLI811 (EM Industries, Houghton, NY). Immerse in. After filling, the cell was removed from the liquid crystal and reduced pressure, washed and the space sealed with epoxy.

The cell is placed between parallel and crossed polarizers in the photo light box. For the two polarizer models, the transmittance of the cells was consistent with the twisted nematic orientation of the liquid crystal, and most of the cells provided a pure uniform twisted nematic orientation. The pretilt angle measured using the crystal rotation method was approximately 8 degrees.

<Example 2>

To dianhydride D3 (132.1 mg, 0.5 mmol) in a solution of 4,4'-diaminobenzophenone (95.5 mg, 0.45 mmol) and diamine (8) (25.3 mg, 0.05 mmol) in γ-butyrolactone (1.43 g) Were added all at once. The mixture was stirred at rt for 16 h under a nitrogen atmosphere. A solution of acetic anhydride (0.142 mL, 1.5 mmol) in γ-butyrolactone (1.0 g) and triethylamine (0.21 mL, 1.5 mmol) was added, and then the solution was heated at 120 ° C. for 3 hours. The solution was cooled and diluted to 3% by weight with γ-butyrolactone (5.44 g) to give a polymer solution.

The polymer solution was spun applied, cured and optionally treated at a scanning rate of 0.5 mm / sec as described in Example 1. The results were the same as in Example 1 except that the pretilt was measured at about 18 °.

<Example 3>

2- (trifluoromethyl) -1,4-benzenediamine (1) (44.0 mg, 0.25 mmol), 3,3'-bis (trifluoromethyl) benzidene in γ-butyrolactone (2.0 g) (5) 3,3 ', 4,4'-benzophenonetetracarboxylic dianhydride (D1) (161.1 mg, 0.5 in a solution of (40.0 mg, 0.125 mmol) and diamine (8) (63.3 mg, 0.125 mmol) mmol) was added. The mixture was stirred at rt for 16 h under a nitrogen atmosphere. A solution of acetic anhydride (0.142 mL, 1.5 mmol) in γ-butyrolactone (1.0 g) and triethylamine (0.21 mL, 1.5 mmol) was added, and then the solution was heated at 120 ° C. for 3 hours. The solution was cooled and diluted to 3% by weight with γ-butyrolactone (6.67 g) to give a solution for rotary casting.

The polymer solution was spun applied and treated as described in Example 1 except that the cured and optionally applied substrate was glass free of ITO (Donelli, Mich., Holland). The results were the same as in Example 1 except that the scanning speed was 0.5 mm / sec and the pretilt was measured at about 31 °.

<Example 4>

dianhydride (D1) (161.1 mg, in a solution of 4,4'-diaminobenzophenone (95.5 mg, .045 mmol) and diamine (8) (25.3 mg, 0.05 mmol) in γ-butyrolactone (1.75 g), 0.5 mmol) were added all at once. The mixture was stirred at rt for 16 h under a nitrogen atmosphere. The solution was diluted to 3% by weight with γ-butyrolactone (7.37 g) to obtain a polymer solution for spin casting.

Example 1 except that the polymer solution was spin-coated, the cured and optionally used liquid crystal was MLC6043-000 (EM Industries, NY, Houghton) containing 0.1% ZLI811, and the scanning rate was 1.5 mm / sec. Treatment was as described. The results were the same as in Example 1 except the pretilt was about 10 °.

<Example 5>

1,2,3,4-butanetetra in a solution of 4,4'-diaminobenzophenone (95.5 mg, 0.45 mmol) and diamine (8) (25.3 mg, 0.05 mmol) in γ-butyrolactone (1.25 g) Carboxylic dianhydride (D7) (99.0 mg, 0.5 mmol) was added all at once. The mixture was stirred at rt for 16 h under a nitrogen atmosphere. A solution of dianhydride acetic acid solution (0.142 mL, 1.5 mmol) in γ-butyrolactone (1.0 g) and triethylamine (0.21 mL, 1.5 mmol) was then added, and the solution was heated at 120 ° C. for 3 hours. The solution was cooled and diluted to 3% by weight with γ-butyrolactone (4.55 g) to obtain a polymer solution for spin casting.

The polymer solution was spun applied and treated as described in Example 1 except that the curing and optionally scanning speed was 0.5 mm / sec. The results were the same as in Example 1 except that the pretilt was measured at about 20 °.

<Example 6>

dianhydride (D7) (99.0 mg, 0.5 in a solution of 4,4'-diaminobenzophenone (100.8 mg, 0.475 mmol) and diamine (8) (12.7 mg, 0.025 mmol) in γ-butyrolactone (1.20 g) mmol) were added all at once. The mixture was stirred at rt for 16 h under a nitrogen atmosphere. A solution of acetic anhydride (0.142 mL, 1.5 mmol) in γ-butyrolactone (1.0 g) and triethylamine (0.21 mL, 1.5 mmol) was added, and then the solution was heated at 120 ° C. for 3 hours. The solution was cooled and diluted to 4% by weight with γ-butyrolactone (2.59 g) to obtain a polymer solution for spin casting.

The polymer solution was spin applied and treated as described in Example 1 except that the curing and optionally the injection rate was 1.5 mm / sec. The results were the same as in Example 1 except that the pretilt was measured at about 22 °.

<Example 7>

To a solution of diamine (1) (83.6 mg, 0.475 mmol) and diamine (8) (12.7 mg, 0.025 mmol) in γ-butyrolactone (1.46 g), all of the dianhydride (D1) (161.1 mg, 0.5 mmol) at a time Added. The mixture was stirred at rt for 16 h under a nitrogen atmosphere. Dilution with 4% by weight of γ-butyrolactone (4.72 g) gave a polymer solution for spin casting.

The polymer solution was spin applied and treated as described in Example 1 except that the curing and optionally the injection rate was 5 mm / sec. The results were the same as in Example 1 except that the pretilt was measured at about 8 °.

<Example 8>

To a solution of 5- (trifluoromethyl) -1,3-benzenediamine (2) (660. mg, 0.375 mmol) and diamine (8) (63.3 mg, 0.125 mmol) in γ-butyrolactone (1.46 g) Dianhydride (D1) (120.8 mg, 0.375 mmol) and dianhydride (D3) (33.0 mg, 0.125 mmol) were added all at once. The mixture was stirred at rt for 16 h under a nitrogen atmosphere. Dilution to 4% by weight with γ-butyrolactone (5.19 g) gave a polymer solution for spin casting.

The polymer solution was spin applied and treated as described in Example 1 except that the curing and optionally the injection rate was 0.25 mm / sec. The results were the same as in Example 1 except that the pretilt was measured at about 10 °.

<Example 9>

dianhydride (D1) (161.1 mg, 0.5) in a solution of 4,4'-diaminobenzophenone (79.68 mg, 0.375 mmol) and diamine (10) (47.0 mg, 0.125 mmol) in γ-butyrolactone (1.92 g) mmol) were added all at once. The mixture was stirred at rt for 16 h under a nitrogen atmosphere. A solution of acetic anhydride (0.142 mL, 1.5 mmol) in γ-butyrolactone (1.0 g) and triethylamine (0.21 mL, 1.5 mmol) was added, and then the solution was heated at 120 ° C. for 3 hours. The solution was cooled and diluted to 4% by weight with γ-butyrolactone (4.98 g) to obtain a polymer solution for spin casting.

The polymer solution was spin applied and treated as described in Example 1 except that the curing and optionally the injection rate was 1.5 mm / sec. More than 1 ° pretilt was observed according to the crystal rotation method.

<Example 10>

4- (1H, 1H, 11H-Eicosafluoro-1-undecyloxy) -1,3-benzenediamine (9) (39.9 mg, 0.0625 mmol in N-methylpyrrolidone (NMP) (0.89 g) ) And 4,4'-diaminostilbene (13.1 mg, 0.0625 mmol) were added dianhydride (D1) (40.25 mg, 0.125 mmol) in NMP (0.89 g). The mixture was stirred at rt for 17 h under a nitrogen atmosphere. The mixture was diluted to 1% by weight with anhydrous tetrahydrofuran (THF) (7.15 g) to give a polymer solution for spin casting.

The polymer solution was spin-coated and treated as described in Example 1 except that the cured and optionally applied substrates were glass without ITO and the scanning speed was 1.5 mm / sec. The results were the same as in Example 1 except that the pretilt was measured at about 23 °.

<Example 11>

1,3,4- (N, N-dioctadecyl) benzenetriamine (16) (39.2 mg, 0.0625 mmol) and 4,4'-diaminostilbene (13.1 mg, 0.0625 mmol in NMP (0.88 g) To the solution was added a solution of dianhydride (D1) (40.2 mg, 0.125 mmol) in NMP (0.88 g). The mixture was stirred at rt for 18 h under a nitrogen atmosphere. The mixture was diluted to 1% by weight with anhydrous tetrahydrofuran (THF) (6.65 g) to give a polymer solution for spin casting.

The polymer solution was spin-coated and treated as described in Example 1 except that the cured and optionally applied substrates were glass without ITO and the scanning speed was 1.5 mm / sec. The results were the same as in Example 1 except that the pretilt was measured at about 28 °.

<Example 12>

3-trifluoromethyl-4- (3'-trifluoromethyl-4'-aminophenyl) azobenzeneamine (C) was first prepared by the following method.

2-trifluoromethyl-4-nitro-benzeneamine (4.92 g, 23.8 mmol) suspended in 5N hydrochloric acid (15.8 mL) and ice (16 g) was added with 2M sodium nitrate (12.6 mL, 25 mmol). Diazoation was by coupling to 0-5 ° C. with 3-trifluoromethylbenzeneamine (5.0 g, 31 mmol) in 5 N hydrochloric acid (8 mL). The mixture was stirred often for 5 hours and basified with 25% aqueous potassium carbonate solution. The resulting solid was recrystallized from THF-ethanol (1: 1) to give 4- (3'-trifluoromethyl-4'-nitrophenyl) azobenzeneamine (1.8 g, melting point 144.0-145.5 ° C).

The monoazo nitroamine (1.65 g, 4.36 mmol) in ethanol (20 mL) was treated with a solution of sodium sulfide hexahydrate (2.1 g, 8.7 mmol) in water (2 mL). The mixture was heated at 80 ° C. for 0.5 h, and then an equal amount of sodium sulfide hexahydrate solution was added. The mixture was heated for 1 h and diluted with water (200 mL). The resulting solid was dissolved in hot ethanol, filtered and ethanol removed to give 3-trifluoromethyl-4- (3'-trifluoromethyl-4'-aminophenyl) azobenzeneamine (melting point 135.5-136.5 ° C.) Obtained.

Diamine (8) (31.6 mg, 0.0625 mmol) and 3-trifluoromethyl-4- (3'-trifluoromethyl-4'-aminophenyl) azobenzeneamine (C) (21.7 mg in NMP (0.89 g) , 0.0625 mmol) was added a solution of dianhydride (D1) (40.2 mg, 0.125 mmol) in NMP (0.89 g). The mixture was stirred at rt for 18 h under a nitrogen atmosphere. The mixture was diluted with anhydrous tetrahydrofuran (THF) (7.49 g) to 1% by weight solids to obtain a polymer solution for rotary casting.

The polymer solution was spin-coated and treated as described in Example 1 except that the cured and optionally applied substrates were glass without ITO and the scanning speed was 1.5 mm / sec. The results were the same as in Example 1 except that the pretilt was measured at about 40 °.

<Example 13>

This example shows that the polyimide of Example 1 can optically induce liquid crystal orientation when exposed to ultraviolet lamp polarization.

Two coated substrates 7 coated with the polyimide of Example 1 were exposed to an ultraviolet lamp as shown in FIG. 4. The ultraviolet lamp 13 (UV Process Supply, Illinois, Chicago, Model Porta-Cure 1500F) is 16 cm away from the substrate 7 with the application surface facing the lamp. A dielectric polarizer 14 (CVI Laser Corporation, Albuquek, NM) of 7.62 cm × 7.62 cm (3 × 3 inches) was placed in front of the light beam. Polarizer 14 provided a p-polarized light 15 to s-polarized light of about 20: 1 through which wavelengths between 300 and 400 nm were transmitted. The light was then passed through a 1 mm thick soda lime glass plate 16 (Donnell Mirror, Inc., Holland). Glass plate 16 limited about 300 nm (transmittance was less than 10% for any wavelength below 300 nm). In order to prevent the application substrate 7 from being illuminated from unpolarized gloss, an aluminum foil (not shown) was covered to block all light not passing through the polarizer 14. The output of the lamp 13 was set at 200 W / inch and warmed for 10 minutes before placing the applied substrate 7 in front of the light beam.

The power density of the light beams on the substrate 7 was measured at 14 mW / cm 2 using a Control Cure compact radiometer from UV Process Supply (Chicago, Ill.). The substrate was exposed for 10 minutes, the cells were assembled and filled as in Example 1.

The results were the same as in Example 1. Pretilt exceeding 1 degree was observed by the crystal rotation method.

<Example 14>

To a solution of diamine (1) (79.2 mg, 0.45 mmol) and diamine (8) (25.3 mg, 0.05 mmol) in γ-butyrolactone (1.84 g) all of dianhydride (D1) (161.1 mg, 0.5 mmol) at a time Added. The mixture was stirred at rt for 16 h under a nitrogen atmosphere. The solution was diluted to 4% by weight with γ-butyrolactone (4.53 g), filtered through 0.45 μm Teflon filter paper and rotated at 2500 rpm on a 2.29 cm × 3.05 cm (0.9 inch × 1.2 inch) soda-lime glass substrate. Applied. The applied substrates were dried under nitrogen atmosphere for 0.25 hours at 80 ° C. and 1 hour at 180 ° C. and stored under nitrogen atmosphere at room temperature until use.

The polymer solution was spin applied and treated as described in Example 1 except that the curing and optionally scanning speed was 0.5 mm / sec. The results were the same as in Example 1 except that the pretilt was measured at about 17 °.

<Example 15>

To a solution of 4,4'-diaminobenzophenone (79.6 mg, 0.375 mmol) and diamine (12) (47.0 mg, 0.125 mmol) in γ-butyrolactone (1.63 g) (161.1 mg, 0.5 mmol) were added all at once. The mixture was stirred at rt for 16 h under a nitrogen atmosphere. The solution was diluted to 4% by weight with γ-butyrolactone (5.27 g) to obtain a polymer solution for spin casting.

The polymer solution was spin applied and treated as described in Example 1 except that the curing and optionally the injection rate was 1.5 mm / sec. The results were the same as in Example 1 except that the pretilt was measured to be greater than 1.0 °.

If the liquid crystal display device manufactured according to each of the above embodiments is visually observed by optically inducing pretilt and then magnified by 100 times between the cross polarizers, the liquid crystal display device is substantially free of irregularities in the alignment pattern generated from scratch. There will be significant irregularities in the liquid crystal display element mechanically buffed to.

<Example 16>

This example shows that the polyimide of Example 1 can optically induce the orientation and pretilt of the liquid crystal when exposed to polarized light of oblique incidence.

Two coated substrates were exposed in the same manner as in Example 1 except that the scanning speed was 1.5 mm / sec. The same substrate was then exposed to p-polarized light (light polarized in the incidence plane) at about 70 ° inclination angle from the perpendicular to the substrate, in the plane of incidence defined by the substrate and the perpendicular to the incident light. The scan direction was the plane of incidence and was the same direction for the initial orthogonal incident exposure. The scanning speed of the oblique exposure was chosen to be 9 mm / sec, and the cylindrical lens used to focus the p-polarized light on the substrate had a 10 cm focal length.

The cell was assembled and charged as in Example 1. The cell is placed between parallel and cross polarizers on the photo light box. For the two polarizer models, the transmittance of the cell was consistent with the twisted nematic orientation of the liquid crystal, and most of the cells provided a pure twisted nematic orientation. However, the loss caused by the inflow of the liquid crystal into the cell can be observed. The pretilt angle measured using the crystal rotation method was approximately 29 degrees.

<Example 17>

This embodiment heats the optically oriented liquid crystals above the isotropic transition temperature, and then cools below the isotropic transition temperature to stabilize the size of the pretilt measured according to the exposure conditions and eliminates the losses that occur during charging of the cell. Shows.

The cell of Example 16 was heated for 30 minutes at 120 ° C. on a Mettler FP52 hotplate (Mettler Corporation, Highstown, NJ), the cell was removed and the cell was placed in an area with two projections in the air. It was maintained and cooled to below isotropic temperature (100 ° C. for ZLI4792) by observing the cells in the crossed polarizers being completely introduced into the nematic phase.

The results were the same as in Example 16 except no loss by flow was observed. Disclination lines were observed at the edge of the cell, but very few were observed in the cell center region. The pretilt angle was measured at about 5 ° and was stable at room temperature.

<Example 18>

This example shows that the heating and cooling cycles of Example 17 stabilize the size and direction of the pretilt as measured according to the exposure conditions and eliminate the losses that occur during cell filling.

The cell was charged perpendicular to the charging direction used in Example 16, where the charging direction is along a bisector in the scanning direction on the substrate. The crystal rotation method found that the pretilt exhibited a new filling direction for the cells of Examples 1-16, ie approximately and -45 ° vertically (indicated by 90 ° twist in the orientation direction between the substrates). This orientation results in an oblique shape of the cell for ZLI4792 with ZLI811 added.

After the cells were heated and cooled circulated in Example 17, the pretilt was determined to be approximately + and −45 ° relative to bisectors in the pretilt (scanning) direction on each substrate as determined by the exposure conditions via the crystal rotation method. Was observed. The pretilt had a size of about 1.5 ° and was thermally stable at room temperature. Therefore, after heating and cooling, the pretilt direction was changed by 90 degrees compared with the cell before thermal cycling. This new orientation yielded a cell that was not oblique with respect to ZLI4792 with ZLI811 added, which coincided with the pretilt orientation of Example 1. In Example 17, there was no loss caused by the flow, and defect lines were formed near the cell edges.

<Example 19>

This example shows that pretilt can be controlled by changing the heating and cooling cycles of the optically oriented cell.

Four cells were exposed, assembled and charged as in Example 16. The first cell was heated and cooled as in Example 17 to produce about 4 ° pretilt, no loss due to flow, and defect lines formed near the cell edges.

The second cell is heated and cooled for 30 minutes at 120 ° C. in a VWR (Bridgeport, NJ) 1410 oven, cooled by stopping the reaction (the cell is immediately placed on a countertop at room temperature), and the resulting pretilt is approximately 10 °. Losses due to flow disappeared and somewhat more defect lines were formed near the cell edges compared to the heating and cooling cycles of Example 17.

The third cell was heated and cooled at 120 ° C. for 30 minutes in a VWR 1410 oven and slowly cooled to 50 ° C. over about 2.5 hours. The pretilt was approximately 2.5 °, the loss due to flow disappeared, and very few defect lines were formed near the cell edges.

The fourth cell was heated and cooled at 120 ° C. for 90 minutes in a VWR 1410 oven and cooled as described in Example 17. The pretilt was approximately 5 °, the loss due to flow disappeared, and many defect lines were formed near the cell edges compared to the heating and cooling circulation of Example 17.

Claims (95)

(a) exposing the at least one optical alignment layer comprising anisotropic absorbing molecules and hydrophobic moieties to polarized light having a wavelength belonging to the absorption band of the anisotropic absorbing molecule so that the exposed anisotropic absorbing molecules are optical with respect to the polarization direction of the incident light; Inducing liquid crystal medium orientation along the surface of the alignment layer at + and − angles and inducing pretilt of Φ angle with respect to the surface of the optical alignment layer, (b) applying a liquid crystal medium to the optical alignment layer And inducing pretilt in the orientation of the liquid crystal medium adjacent the surface of the optical alignment layer. The method of claim 1, wherein the anisotropic absorbing molecule and the hydrophobic moiety are covalently bonded to the polymer. The method of claim 1 wherein the anisotropic absorbing molecule is an unbound solute dissolved in a hydrophobic polymer. The method of claim 2, wherein the polymer is a polyimide polymer. 5. The method of claim 4, wherein the polyimide polymer comprises at least one structural element of formula I, wherein the polyimide polymer is a reaction product of at least one tetracarboxylic dianhydride and at least one hydrophobic diamine. <Formula I> (In the above formula, Y is a divalent group selected from formulas II and III; M is a tetravalent organic group derived from said tetracarboxylic dianhydride containing two or more carbon atoms, and no more than two carbonyl groups in said dianhydride are attached to any one carbon atom of said tetravalent group) <Formula II> <Formula III> Wherein Z is -S-, -O-, -SO _2- , -CH _2- , -C (CF ₃ ) _2- , -C (O)-, -CH ₂ CH _2- , -NR- ( Wherein R is C ₁ -C ₄ hydrocarbon chain) and a covalent bond; X is R ₁ , -OR ₁ , -SR ₁ , -N (R ₂ ) -R ₁ , wherein R ₁ is a C ₄ -C ₂₀ perfluorinated alkyl chain, a C ₄ -C ₂₀ partial fluorinated alkyl chain, And C _{2 0} -C ₂₀ hydrocarbon chains independently, R ₂ is independently selected from H, C ₁ -C ₉ hydrocarbon chains and R ₁ ; X ₁ is independently selected from X and H. The method of claim 5 wherein the polyimide polymer is a copolyimide further comprising at least one structural element of formula (Ia), wherein the ratio of structural elements of formula (I) and formula (Ia) in the copolyimide is from 1:99 to 99 : 1 way. <Formula Ia> In the above formula, Y ₁ is a divalent organic group different from Y having two or more carbon atoms; M is as described in Claim 5. 6. The process of claim 5 wherein said tetracarboxylic dianhydride is a diaryl ketone tetracarboxylic dianhydride and said structural element of formula (I) is a compound of formula (IV). <Formula IV> In the above formula, X ₂ is H, Cl, F, Br, R ₃ and R ₃ O- (where R ₃ is a C ₁ -C ₃ perfluorinated alkyl chain, a C ₁ -C ₃ partial fluorinated alkyl chain and C ₁ -C independently selected from ₈ hydrocarbon chain) with independently selected from the group consisting of; m is 1 or 0; Z and Y are as defined in claim 5. The method according to claim 5, wherein the at least one tetracarboxylic dianhydride is an alicyclic tetracarboxylic dianhydride. 8. The method of claim 7, wherein the polyimide polymer is a copolymer further comprising a structural element of Formula V, further comprising an alicyclic tetracarboxylic dianhydride. <Formula V> In the above formula, P is a tetravalent organic group derived from the alicyclic tetracarboxylic dianhydride containing 4 or more carbon atoms, and at most one carbonyl group in the dianhydride is attached to any one carbon atom of the tetravalent group. Become; Y is as defined in claim 5. The method of claim 9, wherein the copolymer comprises structural elements of Formulas IV and V in a ratio of 1:10 to 99: 1. The alicyclic tetracarboxylic dianhydride according to claim 9, wherein the alicyclic tetracarboxylic dianhydride is 5- (2,5-dioxotetrahydro) -3-methyl-3-cyclohexene-1,2-dicarboxylic anhydride, 2, 3,5-tricarboxycyclopentaneacetic dianhydride, 1,2,3,4-butanetetracarboxylic dianhydride and cyclobutanetetracarboxylic dianhydride. 8. The method of claim 7, wherein said diaryl ketone tetracarboxylic dianhydride is 3,3 ', 4,4'-benzophenonetetracarboxylic dianhydride. The method of claim 5 wherein said polyimide polymer is a copolyimide further comprising at least one structural element of Formula VI. <Formula VI> In the above formula, X ₂ is H, Cl, F, Br, R ₃ and R ₃ O- (where R ₃ is a C ₁ -C ₃ perfluorinated alkyl chain, a C ₁ -C ₃ partial fluorinated alkyl chain and C ₁ -C independently selected from ₈ hydrocarbon chain) with independently selected from the group consisting of; M is as described in Claim 5. 6. The method of claim 5, wherein the hydrophobic diamine is 4- (1H, 1H-pentadecafluoro-1-octyloxy) -1,3-benzenediamine, 4- (1H, 1H, 11H-eicosafluoro-1 -Undecyloxy) -1,3-benzenediamine, 4- (1-octadecyloxy) -1,3-benzenediamine, 4- (1-hexadecyl) -1,3-benzenediamine and 2- ( 1-octadecyloxy) -1,4-benzenediamine. The method of claim 1, wherein said anisotropic absorbing molecule is selected from the group of arylazo, poly (arylazo), stilbene, and diaryl ketone derivatives. The method of claim 1, wherein the anisotropic absorbing molecule is selected from the group of arylazo, stilbene and diaryl ketone derivatives having a maximum absorbance of 150 to 400 nm. The method of claim 1, wherein the anisotropic absorption molecule is 4,4'-diaminostilbene; 2,4-diaminophenylhydrazone of benzophenone, 4,4'-diaminobenzophenone and 3,3'-bis (trifluoromethyl) benzophenone; And diazodiamine A. The method of claim 1, wherein the anisotropic absorbing molecule is benzophenone, 4,4'-bis (trifluoromethyl) benzophenone, 3,4'-bis (trifluoromethyl) benzophenone, 3,3'-bis (Trifluoromethyl) benzophenone; And phenylhydrazone of benzophenone, 4,4'-bis (trifluoromethyl) benzophenone and 3,4'-bis (trifluoromethyl) benzophenone; And 3,3'-bis (trifluoromethyl) benzophenone. The method of claim 1 wherein the polarization is laser light. The method of claim 1, wherein the polarized light is a light source selected from the group of mercury arc, xenon deuterium, and quartz tungsten halogen lamps, and black light together with the polarizer. A liquid crystal display device manufactured from the method of claim 1. A polyimide comprising at least two structural elements of formulas IV and V, which are the reaction products of at least one diaryl ketone tetracarboxylic dianhydride, at least one hydrophobic diamine and at least one alicyclic tetracarboxylic dianhydride Composition. <Formula IV> <Formula V> Wherein Y is a divalent group selected from formulas (II) and (III) below; X ₂ is H, Cl, F, Br, R ₃ and R ₃ O- (where R ₃ is a C ₁ -C ₃ perfluorinated alkyl chain, a C ₁ -C ₃ partial fluorinated alkyl chain and C ₁ -C independently selected from ₈ hydrocarbon chain) with independently selected from the group consisting of; m is 1 or 0; P is a tetravalent organic group derived from the alicyclic tetracarboxylic dianhydride containing four or more carbon atoms, and at most one carbonyl group in the dianhydride is attached to any one carbon atom of the tetravalent group. being) <Formula II> <Formula III> Wherein Z is -S-, -O-, -SO _2- , -CH _2- , -C (CF ₃ ) _2- , -C (O)-, -CH ₂ CH _2- , -NR- ( Wherein R is independently a C ₁ -C ₄ hydrocarbon chain) and a covalent bond; X is R ₁ , -OR ₁ , -SR ₁ , -N (R ₂ ) -R ₁ , wherein R ₁ is a C ₄ -C ₂₀ perfluorinated alkyl chain, a C ₄ -C ₂₀ partial fluorinated alkyl chain, And C _{2 0} -C ₂₀ hydrocarbon chains independently, R ₂ is independently selected from H, C ₁ -C ₉ hydrocarbon chains and R ₁ ; X ₁ is independently selected from X and H. The composition of claim 22, wherein the copolymer comprises structural elements of Formulas IV and V in a ratio of 1:10 to 99: 1. The composition of claim 22, wherein said hydrophobic diamine comprises from 1.0 to 50 mol% of a diamine component. The composition of claim 22, wherein the hydrophobic diamine comprises 1.0 to 15 mol% of a diamine component. 24. The composition of claim 23, wherein the copolyimide further comprises at least one structural element of Formulas VII and VIII, further derived from at least one diaminobenzophenone. <Formula VII> <Formula VIII> In the above formula, Z, X ₂ , P and m are as described in claim 22. The alicyclic tetracarboxylic dianhydride according to claim 22, wherein the alicyclic tetracarboxylic dianhydride is 5- (2,5-dioxotetrahydro) -3-methyl-3-cyclohexene-1,2-dicarboxylic acid anhydride, 2, 3,5-tricarboxycyclopentaneacetic dianhydride, 1,2,3,4-butanetetracarboxylic dianhydride and cyclobutanetetracarboxylic dianhydride. 23. The composition of claim 22, wherein said cycloaliphatic tetracarboxylic dianhydride is 5- (2,5-dioxotetrahydro) -3-methyl-3-cyclohexene-1,2-dicarboxylic acid anhydride. The method of claim 22, wherein the hydrophobic diamine is 4- (1H, 1H-pentadecafluoro-1-octyloxy) -1,3-benzenediamine, 4- (1H, 1H, 11H-eicosafluoro-1 -Undecyloxy) -1,3-benzenediamine, 4- (1-octadecyloxy) -1,3-benzenediamine, 4- (1-hexadecyl) -1,3-benzenediamine and 2- ( 1-octadecyloxy) -1,4-benzenediamine. 23. The composition of claim 22, wherein said diaryl ketone tetracarboxylic dianhydride is 3,3 ', 4,4'-benzophenonetetracarboxylic dianhydride. A polyimide composition comprising at least two structural elements of Formulas (IV) and (VII), which are reaction products of at least one diaryl ketone tetracarboxylic dianhydride, at least one hydrophobic diamine, and at least one diaminobenzophenone. <Formula IV> <Formula VII> Wherein Y is a divalent group selected from formulas (II) and (III) below; X ₂ is H, Cl, F, Br, R ₃ and R ₃ O- (where R ₃ is a C ₁ -C ₃ perfluorinated alkyl chain, a C ₁ -C ₃ partial fluorinated alkyl chain and C ₁ -C independently selected from ₈ hydrocarbon chain) with independently selected from the group consisting of; m is 1 or 0) <Formula II> <Formula III> Wherein Z is -S-, -O-, -SO _2- , -CH _2- , -C (CF ₃ ) _2- , -C (O)-, -CH ₂ CH _2- , -NR- ( Wherein R is independently a C ₁ -C ₄ hydrocarbon chain) and a covalent bond; X is R ₁ , -OR ₁ , -SR ₁ , -N (R ₂ ) -R ₁ , wherein R ₁ is a C ₄ -C ₂₀ perfluorinated alkyl chain, a C ₄ -C ₂₀ partial fluorinated alkyl chain, And C _{2 0} -C ₂₀ hydrocarbon chains independently, R ₂ is independently selected from H, C ₁ -C ₉ hydrocarbon chains and R ₁ ; X ₁ is independently selected from X and H. The diaryl ketone tetracarboxylic anhydride according to claim 31, wherein the diaryl ketone tetracarboxylic anhydride is 3,3 ', 4,4'-benzophenonetetracarboxylic dianhydride and the hydrophobic diamine is 4- (1H, 1H-pentadecafluoro Rho-1-octyloxy) -1,3-benzenediamine, 4- (1H, 1H, 11H-eicosafluoro-1-undecyloxy) -1,3-benzenediamine, 4- (1-octade Selected from the group consisting of siloxy) -1,3-benzenediamine, 4- (1-hexadecyl) -1,3-benzenediamine and 2- (1-octadecyloxy) -1,4-benzenediamine Composition. 33. The composition of claim 32, wherein said diaminobenzophenone is 4,4'-diaminobenzophenone. 32. The composition of claim 31, wherein the hydrophobic diamine comprises about 1.0 to 50 mol% diamine component. 32. The composition of claim 31, wherein the hydrophobic diamine comprises about 1.0 to 15 mol% diamine component. A copolyimide comprising at least two structural elements of Formulas V and VIII, derived from at least one cycloaliphatic tetracarboxylic dianhydride, at least one hydrophobic diamine and at least one diaminobenzophenone A polyimide composition derived from the diamine component and the dianhydride component for causing pretilt in the orientation of the liquid crystal. <Formula V> <Formula VIII> Wherein Y is a divalent group selected from formulas (II) and (III) below; X ₂ is H, Cl, F, Br, R ₃ and R ₃ O- (where R ₃ is a C ₁ -C ₃ perfluorinated alkyl chain, a C ₁ -C ₃ partial fluorinated alkyl chain and C ₁ -C independently selected from ₈ hydrocarbon chain) with independently selected from the group consisting of; P is a tetravalent organic group derived from the alicyclic tetracarboxylic dianhydride containing four or more carbon atoms, and at most one carbonyl group in the dianhydride is attached to any one carbon atom of the tetravalent group. being) <Formula II> <Formula III> Wherein Z is -S-, -O-, -SO _2- , -CH _2- , -C (CF ₃ ) _2- , -C (O)-, -CH ₂ CH _2- , -NR- ( Wherein R is independently a C ₁ -C ₄ hydrocarbon chain) and a covalent bond; X is R ₁ , -OR ₁ , -SR ₁ , -N (R ₂ ) -R ₁ , wherein R ₁ is a C ₄ -C ₂₀ perfluorinated alkyl chain, a C ₄ -C ₂₀ partial fluorinated alkyl chain, And C _{2 0} -C ₂₀ hydrocarbon chains independently, R ₂ is independently selected from H, C ₁ -C ₉ hydrocarbon chains and R ₁ ; X ₁ is independently selected from X and H. The method of claim 36, wherein the alicyclic tetracarboxylic dianhydride is 5- (2,5-dioxotetrahydro) -3-methyl-3-cyclohexene-1,2-dicarboxylic acid anhydride, 2, 3,5-tricarboxycyclopentaneacetic dianhydride, 1,2,3,4-butanetetracarboxylic dianhydride and cyclobutanetetracarboxylic dianhydride. 38. The composition of claim 37, wherein said diaminobenzophenone is 4,4'-diaminobenzophenone. The composition of claim 36, wherein the hydrophobic diamine comprises about 1.0 to 50 mol% diamine component. 37. The composition of claim 36, wherein said hydrophobic diamine comprises about 1.0 to 15 mol% diamine component. A polyimide comprising at least one structural element of formulas IV and IVa, which is a reaction product of at least one diaryl ketone tetracarboxylic dianhydride, at least one hydrophobic diamine and at least one diamine derived from a Y ₂ group Composition. <Formula IV> <Formula IVa> Wherein Y is a divalent group selected from formulas (II) and (III) below; X ₂ is H, Cl, F, Br, R ₃ and R ₃ O- (where R ₃ is a C ₁ -C ₃ perfluorinated alkyl chain, a C ₁ -C ₃ partial fluorinated alkyl chain and C ₁ -C independently selected from ₈ hydrocarbon chain) with independently selected from the group consisting of; m is 1 or 0; Y ₂ is a divalent group selected from formulas IIa and IIIa <Formula II> <Formula III> Wherein Z is -S-, -O-, -SO _2- , -CH _2- , -C (CF ₃ ) _2- , -C (O)-, -CH ₂ CH _2- , -NR- ( Wherein R is independently a C ₁ -C ₄ hydrocarbon chain) and a covalent bond; X is R ₁ , -OR ₁ , -SR ₁ , -N (R ₂ ) -R ₁ , wherein R ₁ is a C ₄ -C ₂₀ perfluorinated alkyl chain, a C ₄ -C ₂₀ partial fluorinated alkyl chain, And C _{2 0} -C ₂₀ hydrocarbon chains independently, R ₂ is independently selected from H, C ₁ -C ₉ hydrocarbon chains and R ₁ ; X ₁ is independently selected from X and H. <Formula IIa> <Formula IIIa> In formula, X ₃ is C ₁ -C ₃ perfluorinated alkyl chain, partially fluorinated alkyl chain or are independently selected from -OCF _3; X ₄ is independently selected from X ₃ and H. 42. The diamine of claim 41 wherein the diamine derived from Y ₂ is 2- (trifluoromethyl) -1,4-benzenediamine, 5- (trifluoromethyl) -1,3-benzenediamine, 2,2 ' -Bis (trifluoromethyl) benzidene, 2,2'-bis (trifluoromethoxy) benzidene and 3,3'-bis (trifluoromethyl) benzedene. 42. The composition of claim 41, wherein said diaryl ketone tetracarboxylic dianhydride is 3,3 ', 4,4'-benzophenonetetracarboxylic dianhydride. 43. The composition of claim 42, wherein the hydrophobic diamine comprises about 1.0 to 50 mol% diamine component. 43. The composition of claim 42, wherein the hydrophobic diamine comprises about 1.0 to 15 mol% diamine component. (a) exposing the at least one optical alignment layer comprising anisotropic absorbing molecules and hydrophobic moieties to polarized light having a wavelength belonging to the absorption band of the anisotropic absorbing molecule so that the exposed anisotropic absorbing molecules are optical with respect to the polarization direction of the incident light; Inducing liquid crystal medium orientation of + and − angles along the surface of the alignment layer and inducing pretilt of Φ angle with respect to the surface of the optical alignment layer; (b) applying a liquid crystal medium having an isotropic point to the optical alignment; (c) heating the liquid crystal medium to a temperature above its isotropic point; And (d) cooling the liquid crystal medium to a temperature below its isotropic point And inducing pretilt in the orientation of the liquid crystal medium adjacent the surface of the optical alignment layer. 47. The method of claim 46, comprising exposing the exposure to two or more polarizations. 47. The method of claim 46, comprising exposing the at least one optical alignment layer to polarized light at an oblique angle of incidence. 49. The method of claim 48, further comprising exposing the optical alignment layer to polarization of a second angle of incidence. The method of claim 49, wherein the polarization of the oblique incident angle and the second incident angle used in the exposure have different polarization directions. The method of claim 46, wherein the liquid crystal medium is heated at a temperature above about 0.01 to 60 ° C. of the isotropic point of the liquid crystal medium. 52. The method of claim 51 comprising heating the liquid crystal medium for about 1 second to 8 hours. The method of claim 51 comprising cooling the liquid crystal medium at a rate of about 1000 to 0.01 ° C./min. The method of claim 53 comprising cooling the liquid crystal medium for about 1 second to 8 hours. 47. The method of claim 46, wherein said anisotropic absorbing molecule and hydrophobic moiety are covalently bound to a polymer. 47. The method of claim 46, wherein said anisotropic absorbing molecule is an unbound solute dissolved in a hydrophobic polymer. The method of claim 55, wherein the polymer is a polyimide polymer. 58. The process of claim 57, wherein the polyimide polymer comprises at least one structural element of formula I, wherein the polyimide polymer is a reaction product of at least one tetracarboxylic dianhydride and at least one hydrophobic diamine. <Formula I> In the above formula, Y is a divalent group selected from formulas II and III; M is a tetravalent organic group derived from said tetracarboxylic dianhydride containing two or more carbon atoms, and no more than two carbonyl groups in said dianhydride are attached to any one carbon atom of said tetravalent group) <Formula II> <Formula III> Wherein Z is -S-, -O-, -SO _2- , -CH _2- , -C (CF ₃ ) _2- , -C (O)-, -CH ₂ CH _2- , -NR- ( Wherein R is C ₁ -C ₄ hydrocarbon chain) and a covalent bond; X is R ₁ , -OR ₁ , -SR ₁ , -N (R ₂ ) -R ₁ , wherein R ₁ is a C ₄ -C ₂₀ perfluorinated alkyl chain, a C ₄ -C ₂₀ partial fluorinated alkyl chain, And C _{2 0} -C ₂₀ hydrocarbon chains independently, R ₂ is independently selected from H, C ₁ -C ₉ hydrocarbon chains and R ₁ ; X ₁ is independently selected from X and H. 59. The polyimide polymer of claim 58 wherein the polyimide polymer is a copolyimide further comprising at least one structural element of formula Ia, wherein the ratio of structural elements of formulas I and Ia in the copolyimide is from 1:99 to 99: 1 How to be. <Formula Ia> In the above formula, Y ₁ is a divalent organic group different from Y having two or more carbon atoms; M is as described in Claim 13. 59. The process of claim 58, wherein said tetracarboxylic dianhydride is a diaryl ketone tetracarboxylic dianhydride and the structural element of formula I is formula IV. <Formula IV> Wherein X ₂ is H, Cl, F, Br, R ₃ and R ₃ O— wherein R ₃ is a C ₁ -C ₃ perfluorinated alkyl chain, a C ₁ -C ₃ partial fluorinated alkyl chain, and Independently selected from C ₁ -C ₈ hydrocarbon chains; m is 1 or 0; Z and Y are as defined in claim 13. 59. The method of claim 58, wherein said at least one tetracarboxylic dianhydride is an alicyclic tetracarboxylic dianhydride. 61. The method of claim 60, wherein the polyimide polymer is a copolymer further comprising a structural element of Formula V, further comprising an alicyclic tetracarboxylic dianhydride. <Formula V> In the above formula, P is a tetravalent organic group derived from the alicyclic tetracarboxylic dianhydride containing 4 or more carbon atoms, and at most one carbonyl group in the dianhydride is attached to any one carbon atom of the tetravalent group. Become; Y is as defined in claim 13. 63. The method of claim 62, wherein the copolymer comprises structural elements of Formulas IV and V in a ratio of 1:10 to 99: 1. 63. The method of claim 62, wherein the cycloaliphatic tetracarboxylic dianhydride is 5- (2,5-dioxotetrahydro) -3-methyl-3-cyclohexene-1,2-dicarboxylic acid anhydride, 2, 3,5-tricarboxycyclopentaneacetic dianhydride, 1,2,3,4-butanetetracarboxylic dianhydride and cyclobutanetetracarboxylic dianhydride. 61. The method of claim 60, wherein said diaryl ketone tetracarboxylic anhydride is 3,3 ', 4,4'-benzophenonetetracarboxylic dianhydride. 59. The method of claim 58, wherein the polyimide polymer is a copolyimide further comprising at least one structural element of Formula VI. <Formula VI> Wherein X ₂ is H, Cl, F, Br, R ₃ and R ₃ O— wherein R ₃ is a C ₁ -C ₃ perfluorinated alkyl chain, a C ₁ -C ₃ partial fluorinated alkyl chain, and Independently selected from C ₁ -C ₈ hydrocarbon chains; M is as defined in claim 13. The method of claim 58, wherein the hydrophobic diamine is 4- (1H, 1H-pentadecafluoro-1-octyloxy) -1,3-benzenediamine, 4- (1H, 1H, 11H-eicosafluoro-1 -Undecyloxy) -1,3-benzenediamine, 4- (1-octadecyloxy) -1,3-benzenediamine, 4- (1-hexadecyl) -1,3-benzenediamine and 2- ( 1-octadecyloxy) -1,4-benzenediamine. 47. The method of claim 46, wherein said anisotropic absorbing molecule is selected from the group of arylazo, poly (arylazo), stilbene, and diaryl ketone derivatives. 47. The method of claim 46, wherein said anisotropic absorbing molecule is selected from the group of arylazo, stilbene, and diaryl ketone derivatives having a maximum absorbance of 150 to 400 nm. 47. The method of claim 46, wherein said anisotropic absorbing molecule is selected from 4,4'-diaminostilbene; 2,4-diaminophenylhydrazone of benzophenone, 4,4'-diaminobenzophenone and 3,3'-bis (trifluoromethyl) benzophenone; And diazodiamine A. 47. The method of claim 46, wherein the anisotropic absorbing molecule is benzophenone, 4,4'-bis (trifluoromethyl) benzophenone, 3,4'-bis (trifluoromethyl) benzophenone, 3,3'-bis (Trifluoromethyl) benzophenone; And phenylhydrazone of benzophenone, 4,4'-bis (trifluoromethyl) benzophenone, 3,4'-bis (trifluoromethyl) benzophenone; And 3,3'-bis (trifluoromethyl) benzophenone. 47. The method of claim 46, wherein said polarization is laser light. 47. The method of claim 46, wherein the polarization is a light source selected from the group of mercury arc, xenon deuterium, and quartz and tungsten halogen lamps, and black light together with the polarizer. 47. The method of claim 46, wherein the polarized light is unpolarized at its light source and is incident on the optical alignment layer at an oblique incident angle. 47. The method of claim 1 or 46, wherein said exposing is performed in a scanning manner. 47. The method of claim 1 or 46, comprising transferring said exposure to said optical alignment layer at between 0.001 and 2000 J / cm 2 within an absorption band of anisotropic absorbing molecules. 47. The method of claim 1 or 46, wherein the exposure is Exposing the at least one optical alignment layer to polarized light at a normal angle of incidence, And exposing the optical alignment layer to polarized light at an oblique angle of incidence. 47. The method of claim 1 or 46, wherein the exposure is Exposing the optical alignment layer to a first direction linearly polarized light of incident light, And exposing the optical alignment layer to second direction linearly polarized light of incident light. 47. The method of claim 1 or 46, wherein the exposure is Exposing the optical alignment layer to a first direction linearly polarized light of incident light, And exposing the optical alignment layer at oblique incidence angles to the second direction linearly polarized light of the incident light. 47. The method of claim 1 or 46, wherein the polarization has one or more wavelengths of about 150 to 800 nm. 47. The method of claim 1 or 46, wherein said polarized light has one or more wavelengths of about 150 to 400 nm. 47. The method of claim 1 or 46, wherein said polarized light has one or more wavelengths of about 300 to 400 nm. 47. The method of claim 1 or 46, comprising capillaryly filling the cell with a liquid crystal medium. 47. The method of claim 1 or 46, comprising casting the liquid crystal medium to the optical alignment layer. 47. The method of claim 1 or 46, wherein the liquid crystal medium is selected from the group consisting of nematic liquid crystals, ferroelectric liquid crystals, polymeric nematic liquid crystals and nematic liquid crystal polymers. 47. The method of claim 1 or 46, wherein said liquid crystal medium is selected from the group consisting of nematic liquid crystals and polymeric nematic liquid crystals. 87. The method of claim 86, wherein the nematic liquid crystals are 4-cyano-4'-alkylbiphenyl, 4-alkyl- (4'-cyanophenyl) cyclohexane and ZLI-5079, ZLI-5080, ZLI-5081, And a perfluorinated liquid crystal mixture selected from the group consisting of ZLI-5092, ZLI-4792, ZLI-1828, MLC-2016, MLC-2019, MLC-6252, and MLC-6043. 47. The method of claim 1 or 46, wherein the orientation of the liquid crystal medium is + and-θ, where θ is 90 ° with respect to the polarization direction. 47. The method of claim 1 or 46, wherein the pretilt of the φ angle is in the range of 1 to 30 degrees or 179 to 150 degrees. 47. The method of claim 1 or 46, wherein the pretilt of the φ angle is in the range of 2-15 degrees or 178-165 degrees. A liquid crystal medium display device made from the method of claim 46. 48. The method of claim 47, wherein the exposure is performed simultaneously. 48. The method of claim 47, wherein the exposure is continuous. 42. A liquid crystal display device made from the composition of claims 22, 31, 36, 41. Two substantially parallel substrates having opposing surfaces, an alignment layer disposed on each of the opposing surfaces, a liquid crystal layer disposed adjacent thereto and at least partially oriented between the alignment layers, and a spacer separating the alignment layers, wherein And at least one of said alignment layers is an optical alignment layer comprising anisotropic absorbing molecules and hydrophobic moieties, wherein the alignment polarizer is substantially free of irregularities in the alignment pattern when viewed at 100 times magnification.