JP2002268068A - Liquid crystal alignment layer, method for aligning bar- shaped liquid crystalline molecule, optical compensation sheet and polarizing plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a liquid crystal alignment layer having a function for aligning bar-shaped liquid crystal molecules perpendicularly to a rubbing direction. SOLUTION: The alignment layer is formed by using a polyimide or a polyamic acid having a carbazole skelton in a side chain.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a liquid crystal alignment film. In addition, the present invention relates to a method for aligning rod-like liquid crystalline molecules perpendicular to a rubbing direction using an alignment film. Furthermore, the present invention also relates to an optical compensatory sheet having, in this order, an alignment film and an optically anisotropic layer formed of rod-like liquid crystalline molecules on a transparent support, and a polarizing plate using the same.

[0002]

2. Description of the Related Art A liquid crystal display device comprises a liquid crystal cell, a polarizing element, and an optical compensation sheet (retardation plate). In a transmission type liquid crystal display device, two polarizing elements are attached to both sides of a liquid crystal cell, and one or two optical compensation sheets are arranged between the liquid crystal cell and the polarizing element. In a reflection type liquid crystal display device, a reflection plate, a liquid crystal cell, one optical compensation sheet, and one polarization element are arranged in this order. The liquid crystal cell includes a rod-like liquid crystal molecule layer, two substrates for enclosing the same, an electrode layer for applying a voltage to the rod-like liquid crystal molecules, and an alignment film layer for controlling the alignment of the rod-like liquid crystal molecules. The liquid crystal cell has a different alignment state of rod-like liquid crystal molecules.
(Twisted Nematic), IPS (In-Plane Switchin)
g), FLC (Ferroelectric Liquid Crystal), OC
B (Optically Compensatory Bend), STN (Supper
Twisted Nematic), VA (Vertically Aligned), E
CB (Electrically Controlled Birefringence), TN and HAN (Hybrid Aligned Nemat)
ic) and various display modes such as GH (Guest-Host).

[0003] Optical compensatory sheets are used in various liquid crystal display devices in order to eliminate coloring of images and to increase the viewing angle. As the optical compensation sheet, a stretched birefringent polymer film has been conventionally used. It has been proposed to use an optical compensatory sheet having an optically anisotropic layer formed of liquid crystal molecules on a transparent support instead of an optical compensatory sheet made of a stretched birefringent film. Since liquid crystal molecules have various alignment forms, it has become possible to realize optical properties that cannot be obtained by a conventional stretched birefringent polymer film by using liquid crystal molecules.

[0004] The optical properties of the optical compensatory sheet are determined according to the optical properties of the liquid crystal cell, specifically, the above-mentioned difference in display mode. When liquid crystal molecules are used, an optical compensation sheet having various optical properties corresponding to various display modes of a liquid crystal cell can be manufactured. Generally, rod-like liquid crystal molecules or discotic liquid crystal molecules are used as the liquid crystal molecules. As the optical compensation sheet using liquid crystal molecules, ones corresponding to various display modes have already been proposed. For example, an optical compensation sheet for a TN mode liquid crystal cell is disclosed in JP-A-6-214116,
It is described in U.S. Pat. Nos. 5,583,679 and 5,646,703 and German Patent Publication No. 391620A1. An optical compensatory sheet for a liquid crystal cell of the IPS mode or the FLC mode is described in JP-A-10-54982. Further, an optical compensatory sheet for a liquid crystal cell of OCB mode or HAN mode is disclosed in US Pat.
No. 3 and International Patent Application WO 96/37804. Further, an optical compensatory sheet for a liquid crystal cell in the STN mode is described in JP-A-9-26572. An optical compensation sheet for a VA mode liquid crystal cell is described in Japanese Patent No. 2866372.

[0005]

SUMMARY OF THE INVENTION An optical compensatory sheet having an optically anisotropic layer formed from rod-like liquid crystalline molecules,
The average direction of the line obtained by projecting the major axis direction of the rod-like liquid crystal molecules onto the surface of the transparent support corresponds to the slow axis of the optical compensation sheet. The average direction of the line obtained by projecting the major axis direction of the rod-like liquid crystal molecules onto the surface of the transparent support generally corresponds to the rubbing direction of the alignment film. The optical compensatory sheet is in the form of a roll in actual production, and the rubbing treatment is most easily performed in the longitudinal direction of the roll-shaped optical compensatory sheet. Therefore, in an optical compensatory sheet having an optically anisotropic layer formed from rod-like liquid crystalline molecules, an embodiment having a slow axis in the longitudinal direction can be most easily produced. The transmission axis of the polarizing film corresponds to a direction perpendicular to the stretching direction of the polymer film forming the polarizing film. The polarizing element is also in a roll shape in actual production, and it is easiest to perform the stretching process in the longitudinal direction of the roll-shaped polarizing film. Accordingly, a polarizing element having a transmission axis in a direction (width direction) perpendicular to the longitudinal direction can be most easily produced.

From the above relationship, when laminating the roll-shaped optical compensation sheet and the roll-shaped polarizing element, the slow axis of the optical compensation sheet and the transmission axis of the polarizing film are arranged so as to be substantially perpendicular to each other. Is the easiest to produce. On the other hand, depending on the display mode of the liquid crystal cell, it may be preferable to arrange the slow axis of the optical compensation sheet and the transmission axis of the polarizing film so as to be substantially parallel. In order for the slow axis of the roll-shaped optical compensatory sheet to be in the width direction of the optical compensatory sheet, it is necessary to align the rod-like liquid crystalline molecules such that the major axis direction is perpendicular to the rubbing direction of the alignment film. is there. In the present specification, "the major axis direction of the rod-shaped liquid crystalline molecules is perpendicular to the rubbing direction of the alignment film" means that the average direction of a line obtained by projecting the major axis direction of the rod-shaped liquid crystalline molecules on the transparent support surface is referred to. ,
It means perpendicular to the rubbing direction. In order to align the rod-like liquid crystal molecules so as to be perpendicular to the rubbing direction, an alignment film having such an alignment function is required. The conventional alignment film has a function of aligning the rod-like liquid crystal molecules in parallel with the rubbing direction.

An object of the present invention is to provide a liquid crystal alignment film having a function of aligning rod-like liquid crystal molecules perpendicular to a rubbing direction. Another object of the present invention is to align rod-like liquid crystal molecules perpendicular to the rubbing direction. Still another object of the present invention is to provide a roll-shaped optical compensation sheet having a slow axis in the width direction. Still another object of the present invention is to provide a polarizing plate that can be easily arranged such that the slow axis of the optical compensation sheet and the transmission axis of the polarizing film are substantially parallel.

[0008]

An object of the present invention is to provide a liquid crystal alignment film of the following (1) to (4), a method of aligning rod-like liquid crystal molecules of the following (5) to (9), and the following (10). And the polarizing plate of the following (11). (1) a liquid crystal alignment film provided on a support,
A liquid crystal alignment film containing polyimide or polyamic acid, wherein the polyimide or polyamic acid has a carbazole skeleton in a side chain. (2) Polyimide or polyamic acid has the following formula (X
The liquid crystal alignment film according to (1), which has a repeating unit represented by I) or (XA) and a repeating unit represented by the following formula (Y):

[0009]

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Wherein X is a tetravalent linking group containing at least one aromatic, aliphatic or heterocyclic ring;
Y is a divalent linking group containing at least one aromatic ring; M is a hydrogen atom, a metal atom or an organic base; and at least one of X and Y is a substituent having a carbazole skeleton. Have]. (3) The substituent having a carbazole skeleton is represented by the following formula (C
The liquid crystal alignment film according to (2), represented by Z):

[0011]

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[Wherein L is a single bond or -O
-, -CO-, -NH-, a divalent linking group selected from the group consisting of an alkylene group, an arylene group, and a combination thereof;
Other benzene rings may be condensed; and the benzene rings A and B and the condensed rings thereof may have a substituent]. (4) The liquid crystal alignment film according to (1), wherein the polyimide or the polyamic acid further has a polymerizable group in a side chain.

(5) A polyimide or polyamic acid having a carbazole skeleton on its side chain is coated on a support to form a coating layer; the surface of the coating layer is rubbed to form an alignment film; and By applying a coating liquid containing rod-like liquid crystal molecules on the substrate and drying, the average direction of the line obtained by projecting the major axis direction of the rod-like liquid crystal molecules onto the transparent support surface and the rubbing direction of the alignment film are adjusted. A method of aligning rod-like liquid crystalline molecules so as to be substantially orthogonal. (6) The rod-shaped liquid crystal molecules have a polymerizable group, and after the rod-shaped liquid crystal molecules are aligned, the rod-shaped liquid crystal molecules are polymerized to fix the alignment state. (5) The rod-shaped liquid crystal molecules are aligned. How to let.

(7) The support is in the form of a roll, and the average direction of a line obtained by projecting the major axis direction of the rod-like liquid crystalline molecules onto the support surface is substantially orthogonal to the longitudinal direction of the support. (5) The method for aligning rod-like liquid crystalline molecules according to (5). (8) The method according to (5), wherein the support has a roll shape, and the rubbing direction of the alignment film is substantially parallel to the longitudinal direction of the support. (9) The method for aligning rod-like liquid crystal molecules according to (5), wherein the rod-like liquid crystal molecules are aligned with an average inclination angle between the major axis direction of the rod-like liquid crystal molecules and the support surface being less than 5 °.

(10) A roll-shaped optical compensation sheet having a transparent support, an alignment film and an optically anisotropic layer formed of rod-like liquid crystalline molecules in this order, wherein the alignment film has a carbazole skeleton on a side chain. The rod-like liquid crystal molecules are composed of polyimide or polyamic acid having, so that the average direction of the lines obtained by projecting the major axis direction of the rod-like liquid crystal molecules on the transparent support surface and the rubbing direction of the alignment film are substantially orthogonal. An optical compensatory sheet characterized in that is oriented.

(11) A roll-shaped polarizing plate having an optically anisotropic layer formed from rod-like liquid crystalline molecules, an alignment film, a transparent support, a polarizing film and a transparent protective film, wherein the alignment film is
It is made of polyimide or polyamic acid having a carbazole skeleton in a side chain, and the rod-like liquid crystal molecules are oriented in a state in which the average tilt angle between the long axis direction of the rod-like liquid crystal molecules and the transparent support surface is less than 5 °, The average direction of the line obtained by projecting the major axis direction of the rod-like liquid crystal molecules on the transparent support surface and the longitudinal direction of the polarizing plate are substantially orthogonal, and the transmission axis of the polarizing film and the rod-like liquid crystal molecules are A polarizing plate, wherein the average direction of a line obtained by projecting a major axis direction onto a surface of a transparent support is substantially parallel.

In this specification, substantially parallel or substantially orthogonal means that the angle difference between the strict parallel and the strict orthogonal is less than 5 °. Preferably, the angle difference is less than 4 °, more preferably less than 3 °, even more preferably less than 2 °, and most preferably less than 1 °.

[0018]

As a result of the study of the present inventors, when polyimide or polyamic acid having a carbazole skeleton in the side chain is used for the liquid crystal alignment film, the rod-like liquid crystal molecules are substantially perpendicular to the rubbing direction. It turned out that it can be uniformly oriented. Thereby, an optical compensation sheet in which the rod-like liquid crystalline molecules are oriented substantially perpendicular to the rubbing direction can be manufactured. Therefore, it has become possible to easily produce a roll-shaped optical compensation sheet having a slow axis in a direction (width direction) perpendicular to the longitudinal direction. On the other hand, as described above, a roll-shaped polarizing element having a transmission axis in a direction perpendicular to the longitudinal direction (width direction) can be most easily produced. Therefore, by laminating the roll-shaped optical compensation sheet and the roll-shaped polarizing element according to the present invention in a roll state,
A polarizing plate in which the slow axis of the optical compensation sheet and the transmission axis of the polarizing film are substantially parallel can be produced. As described above, by using the optical compensation sheet according to the present invention, the optical compensation sheet can be easily arranged such that the slow axis of the optical compensation sheet and the transmission axis of the polarizing film are substantially parallel.

[0019]

FIG. 1 is a schematic diagram showing the basic structure of a transmission type liquid crystal display device. The transmission type liquid crystal display device shown in FIG. 1A includes a transparent protective film (1a), a polarizing film (2a), a transparent support (3a), and an optically anisotropic layer in order from the backlight (BL) side. (4a), lower substrate (5a) of liquid crystal cell, rod-like liquid crystalline molecular layer (6), upper substrate of liquid crystal cell (5b), optically anisotropic layer (4b), transparent support (3
b), a polarizing film (2b), and a transparent protective film (1b). The transparent support and the optically anisotropic layers (3a to 4a and 4b to 3b) constitute an optical compensation sheet. Then, the transparent protective film, the polarizing film, the transparent support, and the optically anisotropic layers (1a to 4a and 4b to 1b) constitute a polarizing plate. The transparent support (3a, 3b) comprises an optically anisotropic layer (4
a) An alignment film is provided on the 4b) side. In addition, the lower substrate (5a) and the upper substrate (5b) of the liquid crystal cell also have an alignment film on the side of the rod-shaped liquid crystalline molecular layer (6).

The transmission type liquid crystal display device shown in FIG. 1B has a transparent protective film (1) in order from the backlight (BL) side.
a), a polarizing film (2a), a transparent support (3a), an optically anisotropic layer (4a), a lower substrate (5a) of a liquid crystal cell, a rod-shaped liquid crystalline molecular layer (6), and an upper substrate of a liquid crystal cell ( 5b), the transparent protective film (1b), the polarizing film (2b), and the transparent protective film (1
c). Transparent support and optically anisotropic layer (3a
4a) constitute an optical compensation sheet. Then, a transparent protective film, a polarizing film, a transparent support and an optically anisotropic layer (1a
To 4a) constitute a polarizing plate. The transparent support (3a)
An alignment film is provided on the optically anisotropic layer (4a) side. In addition, the lower substrate (5a) and the upper substrate (5b) of the liquid crystal cell also have an alignment film on the side of the rod-shaped liquid crystalline molecular layer (6).

The transmission type liquid crystal display device shown in FIG. 1C has a transparent protective film (1) in order from the backlight (BL) side.
a), a polarizing film (2a), a transparent protective film (1b), a lower substrate (5a) of a liquid crystal cell, a rod-like liquid crystalline molecular layer (6), an upper substrate (5b) of a liquid crystal cell, and an optically anisotropic layer ( 4b), a transparent support (3b), a polarizing film (2b), and a transparent protective film (1
c). Transparent support and optically anisotropic layer (4b
3b) constitute an optical compensation sheet. Then, a transparent protective film, a polarizing film, a transparent support, and an optically anisotropic layer (4b
To 1c) constitute a polarizing plate. The transparent support (3b)
An alignment film is provided on the optically anisotropic layer (4b) side. In addition, the lower substrate (5a) and the upper substrate (5b) of the liquid crystal cell also have an alignment film on the side of the rod-shaped liquid crystalline molecular layer (6).

FIG. 2 is a schematic diagram showing a basic configuration of a reflection type liquid crystal display device. The reflection type liquid crystal display device shown in FIG. 2 includes, in order from the bottom, a lower substrate (5a) of a liquid crystal cell, a reflector (RP), a rod-like liquid crystal molecular layer (6), an upper substrate (5b) of the liquid crystal cell, Anisotropic layer (4), transparent support (3),
It comprises a polarizing film (2) and a transparent protective film (1). The transparent support and the optically anisotropic layer (4 to 3) constitute an optical compensation sheet. Then, the transparent protective film, the polarizing film, the transparent support, and the optically anisotropic layer (4-1) constitute a polarizing plate. The transparent support (3) has an alignment film on the optically anisotropic layer (4) side. Further, the reflection plate (RP) and the upper substrate (5b) of the liquid crystal cell also have an alignment film on the rod-like liquid crystal molecular layer (6) side.

FIG. 3 is a schematic view showing a step of bonding a roll-shaped polarizing element and a roll-shaped optical compensation sheet. As shown in FIG. 3, the roll-shaped polarizing element includes a transparent protective film (1) and a polarizing film (2). The roll-shaped optical compensation sheet comprises a transparent support (3) and an optically anisotropic layer (4). The transparent support (3) has an alignment film on the optically anisotropic layer (4) side. The transmission axis of the polarizing film (2) (T
A) is substantially orthogonal to the longitudinal direction (LD) of the roll-shaped polarizing element. The average direction of the line obtained by projecting the major axis direction of the rod-like liquid crystalline molecules of the optically anisotropic layer (4) onto the transparent support surface, that is, the slow axis (SA) is the longitudinal direction of the roll-shaped optical compensation sheet. (LD) is substantially orthogonal. Therefore, as shown in FIG. 3, the transmission axis (TA) of the polarizing film (2) and the retardation of the optically anisotropic layer (4) can be obtained simply by bonding the roll-shaped polarizing element and the roll-shaped optical compensation sheet as they are. It can be arranged such that the phase axis (SA) is substantially parallel. 1 to 3, the order of the transparent support (3) and the optically anisotropic layer (4) may be reversed.

[Alignment Film] For the alignment film, polyimide or polyamic acid having a carbazole skeleton in the side chain is used. The polyimide preferably has a repeating unit represented by the following formula (XI) and a repeating unit represented by the following formula (Y). The polyamic acid has the following formula (XA)
And a repeating unit represented by the following formula (Y).

[0025]

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In the formulas (XI) and (XA), X
Is a tetravalent linking group containing at least one aromatic, aliphatic or heterocyclic ring. Examples of the aromatic ring include a benzene ring and a naphthalene ring. Examples of the aliphatic ring include a cyclobutane ring, a cyclobutene ring, a cyclopentane ring, a cycloheptene ring, a cyclohexane ring, a cyclohexene ring, a cycloheptane and a cycloheptene ring. An aliphatic ring and an aromatic ring may be condensed. Examples of the heterocyclic ring include an oxolane ring. X can also include a linking group other than a cyclic structure. Examples of the linking group other than the cyclic structure include -O-, -CO-, -NH-, (chain).
Includes alkylene groups and combinations thereof. The cyclic structure and the chain alkylene group may have a substituent. Examples of the substituent include an aliphatic group, an aromatic group, a heterocyclic group, -CO-R, -CO-OR and -CO-NH.
-R. In addition, a polymerizable group (Q1 to Q1)
7) is also included in the examples of the substituent. R is an aliphatic group, an aromatic group or a heterocyclic group.

The aliphatic group may have a cyclic structure or a branched structure. The aliphatic group preferably has 1 to 6 carbon atoms. Aliphatic groups include alkyl groups, substituted alkyl groups, alkenyl groups, substituted alkenyl groups, alkynyl groups, and substituted alkynyl groups. Examples of the substituent of the substituted alkyl group, the substituted alkenyl group and the substituted alkynyl group include -CO-R, -CO-OR and -CO-R.
-NH-R. Further, a polymerizable group (Q1
To Q17) are also included as examples of the substituent. R is an aliphatic group, an aromatic group or a heterocyclic group. The aromatic group includes an aryl group and a substituted aryl group. Phenyl and substituted phenyl groups are preferred. Examples of the substituent of the substituted aryl group include an aliphatic group, an aromatic group, a heterocyclic group, -CO-
R, -CO-OR and -CO-NH-R are included. Further, polymerizable groups (Q1 to Q17) described later are also included in examples of the substituent. R is an aliphatic group, an aromatic group or a heterocyclic group. The heterocyclic group is preferably a group containing a carbazole skeleton described below. The heterocyclic group can have a substituent. Examples of the substituent include an aliphatic group, an aromatic group, a heterocyclic group, -CO-R, -CO-OR and-
CO-NH-R. Further, polymerizable groups (Q1 to Q17) described later are also included in examples of the substituent. R is an aliphatic group, an aromatic group or a heterocyclic group.

In the formula (Y), Y is a divalent linking group containing at least one aromatic ring. The aromatic ring is preferably a benzene ring or a naphthalene ring, and more preferably a benzene ring. Y is preferably substituted phenylene, and particularly preferably 5-substituted-1,3-phenylene. As the substituent of the substituted phenylene, a substituent having a carbazole skeleton (described later)
Is preferred. In the formula (XA), M is a hydrogen atom, a metal atom, or an organic base. M is preferably a hydrogen atom. In formulas (XI), (XA) and (Y), at least one of X and Y has a substituent having a carbazole skeleton. The substituent having a carbazole skeleton is preferably a group represented by the following formula (CZ).

[0029]

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In the formula (CZ), L is a single bond or a divalent linking group selected from the group consisting of —O—, —CO—, —NH—, an alkylene group, an arylene group and a combination thereof. is there. Examples of the divalent linking group formed by the combination are shown below. Cz is a carbazole skeleton. L1: -CO-NH-arylene group -CO-Cz L2: -alkylene group-arylene group -Cz L3: -O-CO-arylene group- L4: -NH-CO-arylene group- L5: -CO-NH- Arylene group -CO-L6: -O-CO-arylene group -CO-L7: -O-alkylene group -CO-L8: -CO-O-alkylene group -O-arylene group-
CO- The alkylene group may have a branched or cyclic structure. The number of carbon atoms of the alkylene group is preferably 1 to 30, more preferably 1 to 20, still more preferably 1 to 15, and 1 to 1
Most preferably, it is 2. The arylene group is preferably phenylene or naphthylene, more preferably phenylene, and most preferably p-phenylene. The arylene group may have a substituent. Examples of the substituent of the arylene group are the same as those of the substituent of the substituted aryl group.

In the formula (CZ), each of the benzene rings A and B may be condensed with another benzene ring. In the formula (CZ), the benzene rings A and B and their condensed rings may have a substituent. Examples of the substituent include a halogen atom, an aliphatic group, an aromatic group, a heterocyclic group,
-OR, -CO-R, -O-CO-R, -CO-O-
R, -CO-NH-R, -NH-CO-R, -O-CO
-NH-R. Further, a polymerizable group (Q1
To Q17) are also included as examples of the substituent. R is an aliphatic group, an aromatic group or a heterocyclic group.

The aliphatic group may have a cyclic structure or a branched structure. The aliphatic group preferably has 1 to 6 carbon atoms. Aliphatic groups include alkyl groups, substituted alkyl groups, alkenyl groups, substituted alkenyl groups, alkynyl groups, and substituted alkynyl groups. Examples of the substituent of the substituted alkyl group, the substituted alkenyl group and the substituted alkynyl group include -OR, -CO-R, -O-CO-R,
-CO-OR and -CO-NH-R are included. Further, polymerizable groups (Q1 to Q17) described later are also included in examples of the substituent. R is an aliphatic group, an aromatic group or a heterocyclic group. The aromatic group includes an aryl group and a substituted aryl group. Phenyl and substituted phenyl groups are preferred. Examples of the substituent of the substituted aryl group include an aliphatic group, an aromatic group, a heterocyclic group, -OR, -CO-R, -O-CO-.
R, -CO-OR and -CO-NH-R are included. Further, polymerizable groups (Q1 to Q17) described later are also included in examples of the substituent. R is an aliphatic group, an aromatic group or a heterocyclic group. The heterocyclic group can have a substituent. Examples of the substituent include an aliphatic group, an aromatic group, a heterocyclic group,
-OR, -CO-R, -O-CO-R, -CO-O-
R and -CO-NH-R are included. Further, polymerizable groups (Q1 to Q17) described later are also included in examples of the substituent.
R is an aliphatic group, an aromatic group or a heterocyclic group.

The polyimide or polyamic acid preferably further has a polymerizable group in a side chain. Examples of the polymerizable group are shown below.

[0034]

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The polymerizable group undergoes a polymerization reaction with a polymerizable group (Q) of a rod-like liquid crystal molecule described later, and a polyimide or polyamic acid and the rod-like liquid crystal molecule are combined with each other to form an alignment film and an optically anisotropic layer. Chemical bonding through the interface. Therefore, the type of the polymerizable group is preferably the same as the type of the polymerizable group (Q) of the rod-like liquid crystalline molecule. The polymerizable group (Q) is preferably an unsaturated polymerizable group (Q1 to Q7), an epoxy group (Q8) or an aziridinyl group (Q9), more preferably an unsaturated polymerizable group, and an ethylenic group. Most preferably, it is an unsaturated polymerizable group (Q1 to Q6).

It is preferred that the main chain and the polymerizable group are not directly linked but are linked via a linking group. Examples of linking groups include-
Includes O-, -CO-, -NH-, alkylene groups, arylene groups and combinations thereof. Examples of the linking group consisting of a combination include -O-CO-, -O-CO-N
H-, -CO-O-alkylene group-, -O-alkylene group -O-CO-, -O-CO-NH-alkylene group-,
-O-CO-NH-alkylene group -O-, -O-CO-
NH-alkylene group -CO-O-, -O-CO-NH-
Alkylene group -O-CO-, -O-CO-NH-alkylene group -CO-NH-, -O-CO-alkylene group -O
-CO-, -O-CO-arylene group -O-alkylene group -O-CO-, -O-CO-arylene group -O-alkylene group -O-, -O-CO-arylene group -O-alkylene group -And -O-alkylene groups -O-CO- (the left side is bonded to the main chain, and the right side is bonded to the polymerizable group).

The alkylene group may have a branched or cyclic structure. The number of carbon atoms in the alkylene group is 1
It is preferably from 30 to 30, more preferably from 1 to 20, still more preferably from 1 to 15, and most preferably from 1 to 12. The arylene group is preferably phenylene or naphthylene, more preferably phenylene, and p-
Most preferably, it is phenylene. The arylene group may have a substituent. Examples of the substituent of the arylene group are the same as those of the substituent of the substituted aryl group.

The following is an example of the repeating unit represented by the formula (XI) (a repeating unit derived from a tetracarboxylic acid, wherein the nitrogen atom of the imide is derived from a diamine). (XI-
1) to (XI-4) are repeating units having a substituent having a carbazole skeleton. (XI-5) to (XI-
13) is a repeating unit having no carbazole skeleton.

[0039]

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[0040]

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[0041]

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[0042]

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[0043]

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[0044]

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[0045]

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[0046]

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Examples of the repeating unit represented by the formula (Y) (a repeating unit derived from a diamine, excluding a nitrogen atom) are shown below. Each of the repeating units has a substituent having a carbazole skeleton.

[0048]

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[0049]

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[0050]

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[0051]

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[0052]

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[0053]

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[0054]

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[0055]

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[0056]

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Examples of the polyimide having a carbazole skeleton in the side chain are shown below with reference to the repeating unit (XI) derived from tetracarboxylic acid and the repeating unit (Y) derived from diamine. The proportion of repeating units in the copolymer is mol%.

PI-1:-(XI-1-Y-1)-PI-2:-(XI-1-Y-1) _40- (XI-1-Y)
-2) ₆₀ -PI-3:-(XI-1-Y-1) _10- (XI-5-Y
-1) ₉₀ -PI-4:-(XI-2-Y-1) _10- (XI-5-Y
-1) ₉₀ -PI-5:-(XI-3-Y-1) _5- (XI-6-Y
-1) ₉₅ -PI-6:-(XI-4-Y-1) _5- (XI-5-Y
-1) ₉₅ -PI-7:-(XI-5-Y-1)-PI-8:-(XI-6-Y-1)-PI-9:-(XI-5-Y-4)- PI-10:-(XI-5-Y-11)-

PI-11:-(XI-6-Y-11)-PI-12:-(XI-6-Y-5)-PI-13:-(XI-7-Y-6)-PI- 14 :-( XI-8-Y-10)-PI-15 :-( XI-12-Y-1)-PI-16 :-( XI-13-Y-1)-PI-17 :-( XI -12-Y-11)-PI-18 :-( XI-13-Y-11)-PI-19 :-( XI-12-Y-18)-PI-20 :-( XI-8-Y- 16)-

Examples of the repeating unit represented by the formula (XA) (a repeating unit derived from a tetracarboxylic acid, wherein the nitrogen atom of the amide is derived from a diamine) are shown below. (XA-
1) to (XA-4) are repeating units having a substituent having a carbazole skeleton. (XA-5) to (XA-
13) is a repeating unit having no carbazole skeleton.

[0061]

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[0062]

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[0063]

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[0064]

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[0065]

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[0066]

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[0067]

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[0068]

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[0069]

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A repeating unit in which a carboxyl group (—COOM) of a repeating unit represented by the formula (XA) and a hydroxyl group (—OH) of an alcohol having a polymerizable group (Q) are ester-bonded to a polymerizable group Can be introduced into polyimide or polyamic acid. Examples of such a repeating unit having a polymerizable group are shown below.

[0071]

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[0072]

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[0073]

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[0074]

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[0075]

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[0076]

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[0077]

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[0078]

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[0079]

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[0080]

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[0081]

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[0082]

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[0083]

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[0084]

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[0085]

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[0086]

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Examples of the polyamic acid having a carbazole skeleton in the side chain include a repeating unit (XA) derived from a tetracarboxylic acid, a repeating unit (Y) derived from a diamine, and a repeating unit (XQ) having a polymerizable group. Shown while quoting. The proportion of repeating units in the copolymer is mol%.

PA-1:-(XA-1-Y-1)-PA-2:-(XA-1-Y-1) _40- (XA-1-Y
-2) ₆₀ -PA-3:-(XA-1-Y-1) _10- (XA-5-Y
-1) ₉₀ -PA-4:-(XA-2-Y-1) _10- (XA-5-Y
-1) ₉₀ -PA-5:-(XA-3-Y-1) _5- (XA-6-Y
-1) ₉₅ -PA-6:-(XA-4-Y-1) _5- (XA-5-Y
-1) ₉₅ -PA-7:-(XA-5-Y-1)-PA-8:-(XA-6-Y-1)-PA-9:-(XA-5-Y-4)- PA-10:-(XA-5-Y-11)-

PA-11:-(XA-6-Y-11)-PA-12:-(XA-6-Y-5)-PA-13:-(XA-7-Y-6)-PA- 14 :-( XA-8-Y-10)-PA-15 :-( XA-12-Y-1)-PA-16 :-( XA-13-Y-1)-PA-17 :-( XA -12-Y-11)-PA-18 :-( XA-13-Y-11)-PA-19 :-( XA-12-Y-18)-PA-20 :-( XA-8-Y- 16) - PA-21 :-( XA -6-Y-1) 98 - (XQ-7-
_{Y-1) 2 - PA-} 22 :-( XA-6-Y-1) 98 - (XQ-16
-Y-1) _2-

The orientation film can be obtained by applying a polyamic acid or polyimide to form a coating layer and rubbing the surface of the coating layer. After applying a polyamic acid, a polyimide may be formed by reacting a carboxyl group (—COOM) with an imino group (—NH—) of an amide bond. The rubbing treatment is performed by rubbing the surface of the polymer coating layer several times with paper or cloth in a certain direction (usually the longitudinal direction). The thickness of the alignment film is preferably 0.01 to 5 μm, and more preferably 0.05 to 1 μm. The rod-like liquid crystalline molecules of the optically anisotropic layer may be oriented using an orientation film, and then the optically anisotropic layer may be transferred onto a transparent support. The rod-like liquid crystal molecules fixed in the alignment state can maintain the alignment state without the alignment film.

[Optical Anisotropic Layer] The optically anisotropic layer is formed from rod-like liquid crystal molecules. The rod-like liquid crystalline molecules are preferably oriented in a state where the average tilt angle between the major axis direction of the rod-like liquid crystalline molecules and the transparent support surface is less than 5 °. It is preferable to adjust the retardation of the entire optical compensation sheet by providing an optically anisotropic layer. The in-plane retardation (Re) of the entire optical compensation sheet is preferably from 20 to 200 nm, and more preferably from 20 to 100 nm.
Is more preferable, and most preferably 20 to 70 nm. The retardation (Rth) in the thickness direction of the entire optical compensation sheet is preferably from 70 to 500 nm, more preferably from 70 to 400 m, and further preferably from 70 to 300 nm. The in-plane retardation (Re) and the retardation in the thickness direction (Rth) of the optical compensation sheet are respectively defined by the following equations. Re = (nx−ny) × d Rth = [{(nx + ny) / 2} −nz] × d where nx and ny are in-plane refractive indices of the optical compensation sheet, and nz is the thickness of the optical compensation sheet. And d is the thickness of the optical compensatory sheet. By combining an optically anisotropic layer and a transparent support having optical uniaxiality or optical biaxiality, the retardation of the entire optical compensatory sheet can be adjusted. The transparent support having optical uniaxiality or optical biaxiality will be described later.

The rod-like liquid crystalline molecules used in the optically anisotropic layer are preferably fixed in an aligned state. Although the alignment state can be fixed using a polymer binder, it is preferable to fix the alignment state by a polymerization reaction. Depending on the display mode of the liquid crystal cell, the rod-like liquid crystalline molecules may be cholesterically aligned. When the rod-like liquid crystalline molecules are cholesterically aligned, the selective reflection region is preferably outside the visible region. Examples of rod-like liquid crystal molecules include azomethines, azoxys, cyanobiphenyls, cyanophenyl esters, benzoic esters, cyclohexanecarboxylic acid phenyl esters, cyanophenylcyclohexanes, cyano-substituted phenylpyrimidines, and alkoxy-substituted phenylpyrimidines. , Phenyldioxane, tolan and alkenylcyclohexylbenzonitrile are preferably used. The rod-like liquid crystal molecules also include metal complexes. Further, a liquid crystal polymer containing a rod-like liquid crystal molecule in a repeating unit can also be used as the rod-like liquid crystal molecule. In other words, the rod-like liquid crystalline molecules may be bonded to a (liquid crystal) polymer. For rod-like liquid crystal molecules, see Quarterly Chemistry Review Vol. 22, Chapters 4, 7, and 11 of the Chemical Society of Japan (1994), edited by The Chemical Society of Japan, and the Liquid Crystal Device Handbook, edited by the 142nd Committee of the Japan Society for the Promotion of Science There is a description in Chapter 3. The birefringence of the rod-like liquid crystalline molecules is preferably 0.001 to 0.7.

The rod-like liquid crystalline molecules preferably have a polymerizable group. Examples of the polymerizable group (Q) are the same as the examples of the polymerizable group (Q1 to Q1) of the polyimide or polyamic acid described above.
Same as 7). The polymerizable group (Q) is preferably an unsaturated polymerizable group (Q1 to Q7), an epoxy group (Q8) or an aziridinyl group (Q9), more preferably an unsaturated polymerizable group, and an ethylenic group. Most preferably, it is an unsaturated polymerizable group (Q1 to Q6). The rod-like liquid crystal molecules preferably have a molecular structure that is substantially symmetric with respect to the minor axis direction. For that purpose, it is preferable to have a polymerizable group at both ends of the rod-shaped molecular structure. Hereinafter, examples of rod-like liquid crystal molecules will be described.

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The optically anisotropic layer is composed of rod-like liquid crystal molecules or the following polymerizable initiators and optional additives (eg, plasticizer, monomer, surfactant, cellulose ester, 1,3,5,
-A liquid crystal composition (coating solution) containing a triazine compound and a chiral agent) is applied on the alignment film.
As the solvent used for preparing the liquid crystal composition, an organic solvent is preferably used. Examples of organic solvents include amides (eg,
N, N-dimethylformamide), sulfoxide (eg,
Dimethylsulfoxide), heterocyclic compound (eg, pyridine), hydrocarbon (eg, benzene, hexane), alkyl halide (eg, chloroform, dichloromethane), ester (eg, methyl acetate, butyl acetate), ketone (eg, acetone, Methyl ethyl ketone) and ethers (eg, tetrahydrofuran, 1,2-dimethoxyethane). Alkyl halides and ketones are preferred. Two or more organic solvents may be used in combination. The liquid crystal composition can be applied by a known method (eg, a wire bar coating method, an extrusion coating method, a direct gravure coating method, a reverse gravure coating method, a die coating method).

The polymerization reaction of the rod-like liquid crystal molecules includes a thermal polymerization reaction using a thermal polymerization initiator and a photopolymerization reaction using a photopolymerization initiator. Photopolymerization reactions are preferred. Examples of photopolymerization initiators include α-carbonyl compounds (U.S. Pat.
No. 661, No. 2367670), acyloin ether (described in US Pat. No. 2,448,828), α-hydrocarbon-substituted aromatic acyloin compound (described in US Pat. No. 2,722,512), polynuclear quinone compound (described in US Pat. Patents 3046127 and 2951758), triarylimidazole dimer and p
-Combination with aminophenyl ketone (US Patent 35
No. 49367), acridine and phenazine compounds (described in JP-A-60-105667, U.S. Pat. No. 4,239,850) and oxadiazole compounds (described in U.S. Pat. No. 4,221,970). The amount of the photopolymerization initiator used is 0.1% of the solid content of the coating solution.
It is preferably from 0.01 to 20% by mass, and more preferably from 0.5 to 5% by mass. Light irradiation for the polymerization of the rod-like liquid crystalline molecules is preferably performed using ultraviolet light. The irradiation energy is 20 mJ / cm ^{2 to} 50 J /
cm ² , preferably 100 to 800 mJ /
cm ² is more preferable. Light irradiation may be performed under heating conditions to promote the photopolymerization reaction. The thickness of the optically anisotropic layer is preferably from 0.1 to 20 μm, more preferably from 0.2 to 15 μm, and most preferably from 0.3 to 10 μm.

[Support] The support is preferably transparent. As the transparent support of the optical compensation sheet, a glass plate or a polymer film, preferably a polymer film is used. The support is transparent when the light transmittance is 8
It means 0% or more. Generally, an optically isotropic polymer film is used as a transparent support. Specifically, the optical isotropy means that the in-plane retardation (Re) is preferably less than 10 nm, and 5n
More preferably, it is less than m. In the case of an optically isotropic transparent support, the retardation in the thickness direction (Rth)
Is also preferably less than 10 nm, more preferably less than 5 nm. The in-plane retardation (Re) of the transparent support and the retardation in the thickness direction (Rt)
h) is each defined by the following equation. Re = (nx−ny) × d Rth = [{(nx + ny) / 2} −nz] × d where nx and ny are in-plane refractive indices of the transparent support, and nz is the thickness of the transparent support. Is the refractive index in the direction, and d is the thickness of the transparent support.

Depending on the type of liquid crystal display mode, an optically anisotropic polymer film may be used as the transparent support. That is, in some cases, the optical anisotropy of the optically anisotropic layer is added to the optical anisotropy of the transparent support to correspond to the optical anisotropy of the liquid crystal cell (optical compensation). In such a case, the transparent support preferably has optical uniaxiality or optical biaxiality. In the case of an optically uniaxial support, even if it is optically positive (the refractive index in the optical axis direction is larger than the refractive index in the direction perpendicular to the optical axis), it is negative (the refractive index in the optical axis direction is (Smaller than the refractive index in the vertical direction).
In the case of an optically biaxial support, the refractive indices nx, ny of the above formula
And nz all have different values (nx ≠ ny ≠ nz). In-plane retardation of optically anisotropic transparent support (R
e) is preferably 0 to 300 nm, more preferably 0 to 200 nm, and 0 to 10 nm.
Most preferably, it is 0 nm. The retardation (Rth) in the thickness direction of the optically anisotropic transparent support is preferably from 10 to 1,000 nm, and from 50 to 400 n.
m, more preferably 100 to 300 nm.

The material forming the transparent support is determined depending on whether it is an optically isotropic support or an optically anisotropic support. In the case of an optically isotropic support, glass or cellulose ester is generally used. In the case of an optically anisotropic support, a synthetic polymer (eg, polycarbonate, polysulfone, polyethersulfone, polyacrylate, polymethacrylate, norbornene resin) is generally used. However, the use of (1) the use of a retardation increasing agent (a birefringence increasing agent), (2) a decrease in the degree of acetylation of cellulose acetate, or (3) a cooling dissolution method described in European Patent No. 0911656 A2. By producing a film, an optically anisotropic (high retardation) cellulose ester film can also be produced. The transparent support made of a polymer film is preferably formed by a solvent casting method.

In order to obtain an optically anisotropic transparent support, it is preferable to carry out a stretching treatment on the polymer film.
When an optically uniaxial support is produced, ordinary uniaxial stretching or biaxial stretching may be performed. When producing an optically biaxial support, it is preferable to carry out an unbalanced biaxial stretching treatment. In unbalanced biaxial stretching, a polymer film is stretched in a certain direction at a certain magnification (for example, 3
To 100%, preferably 5 to 30%), and a higher magnification (eg, 6 to 200%) in the direction perpendicular thereto.
%, Preferably 10 to 90%). The bidirectional stretching may be performed simultaneously. It is preferable that the stretching direction (the direction of higher stretching ratio in unbalanced biaxial stretching) and the in-plane slow axis of the stretched film be substantially the same. The angle between the stretching direction and the slow axis is preferably less than 10 °, more preferably less than 5 °, and most preferably less than 3 °. When a transparent support having optical uniaxiality or optical biaxiality is used, the average direction of a line obtained by projecting the major axis direction of the rod-like liquid crystalline molecules of the optically anisotropic layer onto the transparent support surface. Are preferably arranged so as to be substantially parallel or orthogonal to the in-plane slow axis of the transparent support.

The thickness of the transparent support is 10 to 500 μm
Is more preferably 50 to 200 μm. In order to improve the adhesion between the transparent support and the layer provided thereon (adhesion layer, alignment film or optically anisotropic layer), the transparent support is subjected to surface treatment (eg, glow discharge treatment, corona discharge treatment, ultraviolet light). (UV) treatment, flame treatment). An ultraviolet absorber may be added to the transparent support. Adhesion layer (undercoat layer) on transparent support
May be provided. For the adhesion layer, see JP-A-7-333.
No. 433. The thickness of the adhesion layer is preferably from 0.1 to 2 μm, more preferably from 0.2 to 1 μm.

[Polarizing Film] As the polarizing film, an iodine-based polarizing film,
There are a dye-based polarizing film using a dichroic dye and a polyene-based polarizing film. The iodine-based polarizing film and the dye-based polarizing film are generally manufactured using a polyvinyl alcohol-based film. The transmission axis of the polarizing film corresponds to a direction perpendicular to the stretching direction of the film. The transmission axis of the polarizing film is disposed so as to be substantially parallel to the average direction (slow axis) of a line obtained by projecting the major axis direction of the rod-like liquid crystal molecules onto the surface of the transparent support.

[Transparent Protective Film] As the transparent protective film, a transparent polymer film is used. That the protective film is transparent means that the light transmittance is 80% or more. As the transparent protective film, a cellulose ester film, preferably a triacetyl cellulose film, is generally used. The cellulose ester film is preferably formed by a solvent casting method. The thickness of the transparent protective film is preferably 20 to 500 μm,
More preferably, it is 0 to 200 μm.

[Liquid Crystal Display Device] The present invention can be applied to liquid crystal cells of various display modes. As described above, the optical compensation sheet using liquid crystal molecules is formed of a TN (Twisted Nemati).
c), IPS (In-Plane Switching), FLC (Ferroel
ectric Liquid Crystal), OCB (Optically Compensa)
tory Bend), STN (Supper Twisted Nematic), V
A (Vertically Aligned), ECB (Electrically Cont
rolled Birefringence) and HAN (Hybrid Aligne)
dNematic) mode liquid crystal cells have already been proposed. The optical compensatory sheet and the polarizing plate of the present invention are preferably arranged such that the slow axis of the optical compensatory sheet and the transmission axis of the polarizing film are substantially parallel to each other, for example, a TN mode or a VA mode. It is preferable to use it for a liquid crystal display device. The present invention is particularly effective in a VA mode liquid crystal display device. The VA mode liquid crystal cell includes (1) a VA mode liquid crystal cell in a narrow sense in which rod-like liquid crystal molecules are aligned substantially vertically when no voltage is applied and substantially horizontally when voltage is applied. 176
625), and (2) a liquid crystal cell (SID97, Digest of tech. Papers) in which the VA mode is multi-domain (in the MVA mode) in order to enlarge the viewing angle.
(Proceedings) 28 (1997) 845), (3) A mode in which rod-like liquid crystalline molecules are substantially vertically aligned when no voltage is applied, and twisted multi-domain alignment is performed when a voltage is applied (n
-ASM mode) liquid crystal cell (described in Proceedings 58-59 (1998) of Japanese Liquid Crystal Symposium) and (4) SURVA
Includes IVAL mode liquid crystal cells (presented at LCD International 98).

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[Example 1] (Formation of alignment film) Polyimide (PI-8) was dissolved in a mixed solvent of N-methylpyrrolidone / methylethylketone (mass ratio = 1/4) to prepare a 4 mass% solution. Prepared. This solution was applied to a glass support at 1 μm using a bar coater.
To a thickness of The coating layer was heated at 120 ° C. for 5 minutes and dried. The surface of the coating layer was rubbed to form an alignment film.

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(Formation of Optically Anisotropic Layer) On the alignment film,
Using a bar coater, a coating solution having the following composition was 0.7 μm
To a thickness of

<< Composition of Optically Anisotropic Layer Coating Solution >>棒 100 parts by mass of rod-like liquid crystalline molecule (N71) Photopolymerization initiator (Irgacure 907, manufactured by Nippon Ciba Geigy Co., Ltd.) 3 parts by mass Photopolymerization sensitizer (Kayacure DETX, manufactured by Nippon Kayaku Co., Ltd.) 1 part by mass Methyl ethyl ketone 400 parts by mass ──────────────────────

The coating layer was heated at 100 ° C. for 1 minute to align the rod-like liquid crystalline molecules. At that temperature, ultraviolet rays were irradiated for 4 seconds to polymerize the rod-like liquid crystalline molecules, and the alignment state was fixed. Thus, an optically anisotropic layer was formed to produce an optical compensation sheet. Observation of the orientation of the optically anisotropic layer and the director (long axis direction) of the rod-like liquid crystal molecules using a polarizing microscope revealed that the rod-like liquid crystal molecules were oriented so that the long axis direction was orthogonal to the rubbing direction. I was Wavelength 550
When the in-plane retardation (Re) and the retardation in the thickness direction (Rth) in nm were measured using an ellipsometer (M-150, manufactured by JASCO Corporation), Re was 30 nm and Rth was 115 nm. .

Example 2 An optical compensatory sheet was prepared and evaluated in the same manner as in Example 1 except that the same amount of polyimide (PI-9) was used instead of polyimide (PI-8). Observation of the orientation of the optically anisotropic layer and the director (long axis direction) of the rod-like liquid crystal molecules using a polarizing microscope revealed that the rod-like liquid crystal molecules were oriented so that the long axis direction was orthogonal to the rubbing direction. I was When the in-plane retardation (Re) and the retardation in the thickness direction (Rth) at a wavelength of 550 nm were measured using an ellipsometer (M-150, manufactured by JASCO Corporation), Re was 30.
nm and Rth were 110 nm.

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Example 3 A polyimide (PI-11) was used in place of the polyimide (PI-8), except that the same amount was used.
An optical compensatory sheet was prepared and evaluated in the same manner as in Example 1. Observation of the orientation of the optically anisotropic layer and the director (long axis direction) of the rod-like liquid crystal molecules using a polarizing microscope revealed that the rod-like liquid crystal molecules were oriented so that the long axis direction was orthogonal to the rubbing direction. I was The in-plane retardation (Re) and the retardation in the thickness direction (Rth) at a wavelength of 550 nm were measured using an ellipsometer (M-150, manufactured by JASCO Corporation).
nm and Rth were 115 nm.

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Example 4 (Preparation of Transparent Support) 4.0% by mass of the following birefringence increasing agent was added to cellulose triacetate, and the thickness was 100 μm.
m of cellulose triacetate film was prepared. The obtained cellulose triacetate film,
Used as a transparent support.

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(Formation of Alignment Film) Polyamic acid (PA-
21) and a 4% by mass aqueous solution of triethylamine (neutralizing agent) were prepared. This solution was continuously applied onto a roll-shaped transparent support while transporting it using a bar coater. The coating layer was heated at 120 ° C. for 2 minutes and dried to form a coating layer having a thickness of 1 μm. While transporting the roll-shaped transparent support provided with the coating layer, the surface of the coating layer was continuously rubbed in the longitudinal direction (transport direction) to form an alignment film.

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(Formation of Optically Anisotropic Layer) On the alignment film,
A coating solution having the following composition was continuously applied using a bar coater.

<< Composition of Coating Solution for Optically Anisotropic Layer >>棒 100 parts by mass of rod-like liquid crystalline molecule (N71) Photopolymerization initiator (Irgacure 907, manufactured by Nippon Ciba Geigy Co., Ltd.) 3 parts by mass Photopolymerization sensitizer (Kayacure DETX, manufactured by Nippon Kayaku Co., Ltd.) 1 part by mass Methyl ethyl ketone 400 parts by mass ──────────────────────

The coating layer was heated at 100 ° C. for 1 minute to align the rod-like liquid crystal molecules. 600m at that temperature for 4 seconds
The rod-like liquid crystalline molecules were polymerized by irradiating ultraviolet rays of j / cm ² to fix the alignment state. Thus, an optically anisotropic layer was formed to produce an optical compensation sheet. The rod-like liquid crystal molecules were oriented such that the major axis direction was orthogonal to the longitudinal direction of the optical compensation sheet. The in-plane retardation (Re) and the retardation in the thickness direction (Rth) at a wavelength of 550 nm were measured using an ellipsometer (M-150, manufactured by JASCO Corporation).
Rth was 115 nm.

(Preparation of Polarizing Plate) A roll-shaped polyvinyl alcohol film having a thickness of 80 μm was continuously stretched 5 times in an aqueous iodine solution and dried to obtain a polarizing film. On one side of the polarizing film, a saponified rolled cellulose triacetate film (Fujitac TD80UF, manufactured by Fuji Photo Film Co., Ltd.) was provided, and on the other side, a transparent support of a saponified rolled optical compensation sheet was prepared. By continuously bonding, a polarizing plate was produced. The slow axis of the optical compensation sheet (the major axis direction of the rod-like liquid crystalline molecules) was parallel to the transmission axis of the polarizing film.

(Production of Liquid Crystal Display Device) A commercially available MVA liquid crystal display device (VL-1530S, manufactured by Fujitsu Limited) was used.
The polarizing plate on the observer side and the backlight side and the optical compensation sheet were peeled off, and two polarizing plates produced instead were attached. The viewing angle of the manufactured MVA liquid crystal display device was measured with a viewing angle measuring device (EZContrast 160D, manufactured by ELDIM). As a result, the viewing angle in the transmission axis direction of the polarizing film and the viewing angle in the direction at 45 ° from the transmission axis direction exceeded 80 °.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a basic configuration of a transmission type liquid crystal display device.

FIG. 2 is a schematic diagram showing a basic configuration of a reflection type liquid crystal display device.

FIG. 3 is a schematic view showing a step of bonding a roll-shaped polarizing element and a roll-shaped optical compensation sheet.

[Description of Signs] BL backlight LD longitudinal direction RP reflector SA slow axis of optically anisotropic layer TA transmission axis of polarizing film 1, 1a, 1b, 1c transparent protective film 2, 2a, 2b polarizing film 3, 3a, 3b Transparent support 4, 4a, 4b Optically anisotropic layer 5a Lower substrate of liquid crystal cell 5b Upper substrate of liquid crystal cell 6 Rod-like liquid crystal molecular layer

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2H049 BA02 BA06 BA27 BA42 BB03 BB33 BB43 BC03 BC04 BC05 BC09 BC22 2H090 HB08Y JB02 JB03 JB13 KA05 KA07 KA08 KA14 LA06 LA09 LA16 MA01 MB03 2H091 FA08X FA08Z FA11 FB11 GA11 HA07 HA09 HA10 HA12 KA02 4J043 PA04 PC035 PC036 PC165 PC166 QB15 QB26 QB31 RA34 SA05 SA06 TA14 TA22 ZB21 ZB23

Claims (11)

[Claims] 1. A liquid crystal alignment film provided on a support, comprising a polyimide or polyamic acid, wherein the polyimide or polyamic acid has a carbazole skeleton in a side chain. 2. The liquid crystal alignment according to claim 1, wherein the polyimide or polyamic acid has a repeating unit represented by the following formula (XI) or (XA) and a repeating unit represented by the following formula (Y). Membrane: embedded image Wherein X is a tetravalent linking group containing at least one aromatic, aliphatic or heterocyclic ring; Y is a divalent linking group containing at least one aromatic ring; Is a hydrogen atom, a metal atom or an organic base; and at least one of X and Y has a substituent containing a carbazole skeleton. 3. The liquid crystal alignment film according to claim 2, wherein the substituent having a carbazole skeleton is represented by the following formula (CZ): [Wherein L is a single bond, or -O-, -CO-,
A divalent linking group selected from the group consisting of —NH—, an alkylene group, an arylene group and a combination thereof; each of the benzene rings A and B may be condensed with another benzene ring; The benzene rings A and B and the condensed rings thereof may have a substituent]. 4. The liquid crystal alignment film according to claim 1, wherein the polyimide or polyamic acid further has a polymerizable group in a side chain. 5. A coating layer is provided by coating a polyimide or polyamic acid having a carbazole skeleton on a side chain on a support to form an alignment layer by rubbing the surface of the coating layer. By coating and drying the coating liquid containing rod-like liquid crystal molecules on top, the average direction of the line obtained by projecting the long axis direction of the rod-like liquid crystal molecules on the transparent support surface and the rubbing direction of the alignment film are substantially the same. A method in which rod-like liquid crystalline molecules are oriented so as to be orthogonal to each other. 6. The rod-shaped liquid crystal molecule according to claim 5, wherein the rod-shaped liquid crystal molecule has a polymerizable group, and after the rod-shaped liquid crystal molecule is aligned, the rod-shaped liquid crystal molecule is polymerized to fix the alignment state. A method for orienting. 7. The support has a roll shape, and the average direction of a line obtained by projecting the major axis direction of the rod-like liquid crystalline molecules onto the support surface is substantially perpendicular to the longitudinal direction of the support. The method for aligning rod-like liquid crystalline molecules according to claim 5. 8. The method for aligning rod-like liquid crystal molecules according to claim 5, wherein the support is in a roll shape, and the rubbing direction of the alignment film is substantially parallel to the longitudinal direction of the support. 9. The rod-like liquid crystal molecules according to claim 5, wherein the rod-like liquid crystal molecules are oriented in a state where the average inclination angle between the major axis direction of the rod-like liquid crystal molecules and the support surface is less than 5 °. Method. 10. A roll-shaped optical compensation sheet having a transparent support, an alignment film and an optically anisotropic layer formed of rod-like liquid crystal molecules in this order, wherein the alignment film has a carbazole skeleton in a side chain. It consists of polyimide or polyamic acid having, the rod-like liquid crystalline molecules are such that the average direction of the lines obtained by projecting the long axis direction of the rod-like liquid crystalline molecules on the transparent support surface and the rubbing direction of the alignment film are substantially orthogonal. An optical compensation sheet characterized by being oriented. 11. A roll-shaped polarizing plate having an optically anisotropic layer formed from rod-shaped liquid crystalline molecules, an alignment film, a transparent support, a polarizing film and a transparent protective film, wherein the alignment film has side chains. The rod-like liquid crystal molecules are oriented in a state in which the average tilt angle between the long axis direction of the rod-like liquid crystal molecules and the transparent support surface is less than 5 °. The average direction of the line obtained by projecting the major axis direction of the polar molecule onto the transparent support surface and the longitudinal direction of the polarizing plate are substantially orthogonal, and the transmission axis of the polarizing film and the major axis of the rod-like liquid crystalline molecule A polarizing plate, wherein an average direction of a line obtained by projecting a direction onto a transparent support surface is substantially parallel.