JP2006259212A - Retardation plate, its manufacturing method, polarizing plate and image display apparatus using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a retardation plate which contributes to improvement of a visual field angle characteristic of a liquid crystal display. <P>SOLUTION: On a supporting body, the retardation plate has an alignment film comprising a polymer having at least one kind of constitutional units expressed by a general formula (A) and an optical anisotropic layer comprising a bar-shaped smectic A crystalline compound alignment of which is controlled by the alignment film. In the formula, Mp denotes a linking group of (2+n) value combining with L at (n) positions, L denotes a linking group of (1+n) value, (n) denotes 1 or 2 and X denotes a hydrogen-combining group. However formula weight of the constitutional unit expressed by the general formula (A) is 110 or more. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an optically anisotropic layer formed from a rod-like smectic A liquid crystal compound whose orientation is controlled by a specific alignment film, and in particular, by using a specific alignment film, the rod-like smectic A liquid crystal compound The present invention relates to an optically anisotropic layer manufactured by aligning the major axis so as to be substantially perpendicular to the rubbing direction and a method for manufacturing the same. The present invention also relates to a polarizing plate and a liquid crystal display device using the optically anisotropic layer, and more particularly to a vertical alignment nematic liquid crystal display device having excellent viewing angle characteristics.

  A liquid crystal display device usually has a liquid crystal cell, a polarizing element, and an optically anisotropic layer. In a transmissive liquid crystal display device, two polarizing elements are attached to both sides of a liquid crystal cell, and one or two optically anisotropic layers are disposed between the liquid crystal cell and the polarizing element. In a reflective liquid crystal display device, a reflector, a liquid crystal cell, a single optically anisotropic layer, and a single polarizing element are arranged in this order. The liquid crystal cell includes a rod-like liquid crystalline molecule layer, two substrates for enclosing it, an electrode layer for applying a voltage to the rod-like liquid crystalline molecule, and an alignment film layer for controlling the orientation of the rod-like liquid crystalline molecule. The liquid crystal cell is different in the alignment state of rod-like liquid crystal molecules. As for the transmissive type, TN (Twisted Nematic), IPS (In-Plane Switching), FLC (Ferroelectric Liquid Crystals), OCB (Optically Compensatory B) Twisted Nematic), VA (Vertically Aligned), ECB (Electrically Controlled Birefringence), and reflection type are TN, HAN (Hybrid Aligned Nematic), and GH (Guest).

  The optically anisotropic layer is used in various liquid crystal display devices in order to eliminate image coloring and expand the viewing angle. As the optically anisotropic layer, a stretched birefringent polymer film has been conventionally used. It has been proposed to use an optically anisotropic layer having an optically anisotropic layer formed of liquid crystalline molecules on a transparent support instead of the optically anisotropic layer 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 with conventional stretched birefringent polymer films by using liquid crystal compounds as materials.

  The optical properties of the optically anisotropic layer are determined according to the optical properties of the liquid crystal cell, specifically, the difference in display mode as described above. When liquid crystalline molecules are used, optically anisotropic layers having various optical properties corresponding to various display modes of the liquid crystal cell can be produced. In general, rod-like liquid crystal molecules or discotic liquid crystal molecules are used as the liquid crystal molecules. As an optically anisotropic layer using liquid crystal molecules, those corresponding to various display modes have already been proposed. For example, optically anisotropic layers for liquid crystal cells in TN mode are described in each specification of Patent Documents 1 to 4. Patent Documents 5 and 6 describe optically anisotropic layers for liquid crystal cells in IPS mode or FLC mode. Furthermore, OCB mode or HAN mode liquid crystal cell optical anisotropic layers are described in Patent Documents 7 and 8. Furthermore, Patent Document 9 describes an optically anisotropic layer for an STN mode liquid crystal cell. Patent Document 10 describes an optically anisotropic layer for a VA mode liquid crystal cell.

  In order to cope with these various display modes, an alignment film that controls the discotic liquid crystal molecules and rod-like liquid crystal molecules to a desired alignment angle is essential. However, there are cases where a stable alignment state cannot be formed by using a conventional alignment film depending on the alignment angle. For example, as an example of an optically anisotropic layer for optically compensating a liquid crystal cell of VA mode or the like, as schematically shown in FIG. An optically anisotropic layer that is oriented substantially perpendicular to the direction of rubbing applied to the surface of the film and fixed in the oriented state. As a method for aligning the rod-like liquid crystalline molecules so that the major axis thereof is orthogonal to the rubbing direction, for example, as described in Patent Documents 11 to 13, a carbazole ring or the like is substituted with a polymer main chain. A method using an alignment film and a method using polystyrene or the like are known. However, even when these alignment films are used, some of the rod-like liquid crystalline molecules may be aligned with the major axis parallel to the rubbing direction, and there is an alignment film that aligns perpendicularly without any unevenness. It was desired.

In addition, the conventional known methods for aligning the rod-like liquid crystalline compounds are mostly examples of orientation and fixation in a temperature range exhibiting nematic liquid crystallinity, and smectic A liquid crystals having a higher degree of order than nematic liquid crystallinity. A method for aligning in the range of the properties has not been known. If it can be aligned in the temperature range showing the smectic A liquid crystal phase, the alignment uniformity of the rod-like liquid crystalline compound in the optically anisotropic layer is also improved, and when used as a retardation plate, haze is reduced and contrast is reduced. Since suppression is expected, there is a strong demand for alignment films and alignment methods for uniformly aligning rod-like smectic A liquid crystalline compounds, and in particular, a method for uniformly aligning in a direction orthogonal to the rubbing direction is strongly desired. It was desired.
JP-A-6-214116 US Pat. No. 5,583,679 US Pat. No. 5,646,703 German Patent Publication 3911620A1 Japanese Patent Laid-Open No. 9-292522 Japanese Patent Laid-Open No. 10-54982 US Pat. No. 5,805,253 International patent application WO 96/37804 JP-A-9-26572 Japanese Patent No. 2866372 JP 2002-62427 A JP 2002-90545 A JP 2002-98836 A

  The problem to be solved by the present invention is that a rod-like smectic A liquid crystal molecule is oriented with its major axis substantially perpendicular to the rubbing direction without unevenness, and an optically anisotropic layer produced thereby is prepared. Is to provide. Furthermore, by using this optically anisotropic layer, a liquid crystal display device having excellent viewing angle characteristics and contrast, particularly a vertical alignment nematic liquid crystal display device, and a liquid crystal display device, particularly a vertical alignment nematic liquid crystal display device. It is an object to provide a retardation plate that contributes to improvement of characteristics and contrast.

Means for solving the above problems are as follows.
[1] An orientation film containing a polymer having at least one type of structural unit represented by the following general formula (A) on the support, and orientation controlled by the orientation film and fixed in the orientation state. An optically anisotropic layer containing a rod-like smectic A liquid crystalline compound.

（式中、ＭｐはＬとｎ個の部位で結合している（２＋ｎ）価の連結基を表し、Ｌは（１＋ｎ）価の連結基を表し、ｎは１又は２を表し、Ｘは水素結合性基を表す。但し、一般式（Ａ）で表される構成単位の式量は１１０以上である。）

(In the formula, Mp represents a (2 + n) -valent linking group bonded to L at n sites, L represents a (1 + n) -valent linking group, n represents 1 or 2, and X represents hydrogen. Represents a bonding group, provided that the formula weight of the structural unit represented by formula (A) is 110 or more.)

[2] The phase difference according to [1], wherein the structural unit represented by the general formula (A) is represented by any one of the following general formula (I), general formula (II), and general formula (III). Board.

（式中、Ｒ¹は水素原子、メチル基、ハロゲン原子又はシアノ基を表し、Ｐ¹は酸素原子、−ＣＯ−又は−ＮＲ¹²−を表し、Ｒ¹²は水素原子、炭素原子数１〜６の置換もしくは無置換のアルキル基、又は炭素原子数６以上の置換もしくは無置換のアリール基を表し、Ｌ¹は置換もしくは無置換の、アルキレン基、２価の環状脂肪族基、２価の芳香族基、２価のへテロ環基及びこれらの組み合わせからなる群より選ばれる２価の連結基を表し、Ｘ¹は水素結合性基を表し、ｎ１は１以上の整数を表す。）

(In the formula, R ¹ represents a hydrogen atom, a methyl group, a halogen atom or a cyano group, P ¹ represents an oxygen atom, —CO— or —NR ¹² —, and R ¹² represents a hydrogen atom and has 1 to 6 carbon atoms. Represents a substituted or unsubstituted alkyl group or a substituted or unsubstituted aryl group having 6 or more carbon atoms, and L ¹ represents a substituted or unsubstituted alkylene group, divalent cycloaliphatic group, divalent aromatic A divalent linking group selected from the group consisting of a group, a divalent heterocyclic group and a combination thereof, X ¹ represents a hydrogen bonding group, and n1 represents an integer of 1 or more.)

（式中、Ｒ²は水素原子、メチル基、ハロゲン原子又はシアノ基を表し、Ｌ²¹は置換もしくは無置換の、２価の芳香族基又は２価のヘテロ環基を表し、Ｐ²¹は単結合、−Ｏ−、−ＮＲ²¹−、−ＣＯ−、−Ｓ−、−ＳＯ−、−ＳＯ₂−及びこれらの組み合わせからなる群から選ばれる２価の連結基を表し、Ｒ²¹は水素原子又は炭素原子数１〜６の置換もしくは無置換のアルキル基を表し、Ｌ²²は置換もしくは無置換の、アルキレン基、２価の環状脂肪族基、２価の芳香族基、２価のヘテロ環基及びこれらの組み合わせからなる群より選ばれる２価の連結基を表し、Ｘ²は水素結合性基を表し、ｎ２は０以上の整数である。）

(In the formula, R ² represents a hydrogen atom, a methyl group, a halogen atom or a cyano group, L ²¹ represents a substituted or unsubstituted divalent aromatic group or divalent heterocyclic group, and P ²¹ represents a single atom. Represents a divalent linking group selected from the group consisting of a bond, —O—, —NR ²¹ —, —CO—, —S—, —SO—, —SO ₂ — and combinations thereof, and R ²¹ represents a hydrogen atom. Or a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, wherein L ²² is a substituted or unsubstituted alkylene group, divalent cycloaliphatic group, divalent aromatic group, divalent heterocycle. And a divalent linking group selected from the group consisting of a group and a combination thereof, X ² represents a hydrogen bonding group, and n2 is an integer of 0 or more.)

（式中、Ｌ³¹は置換もしくは無置換の、２価の芳香族基又は２価のヘテロ環基を表し、Ｐ³¹は単結合、−Ｏ−、−ＮＲ³¹−、−ＣＯ−、−Ｓ−、−ＳＯ−、−ＳＯ₂−及びこれらの組み合わせからなる群より選ばれる２価の連結基を表し、Ｒ³¹は水素原子又は炭素原子数１〜６の置換もしくは無置換のアルキル基を表し、Ｌ³²は置換もしくは無置換の、アルキレン基、２価の環状脂肪族基、２価の芳香族基、２価のヘテロ環基及びこれらの組み合わせからなる群より選ばれる２価の連結基を表し、Ｘ³は水素結合性基を表し、ｎ３は０以上の整数である。）

(Wherein L ³¹ represents a substituted or unsubstituted divalent aromatic group or divalent heterocyclic group, and P ³¹ represents a single bond, —O—, —NR ³¹ —, —CO—, —S Represents a divalent linking group selected from the group consisting of —, —SO—, —SO ₂ — and combinations thereof, and R ³¹ represents a hydrogen atom or a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms. , L ³² represents a divalent linking group selected from the group consisting of a substituted or unsubstituted alkylene group, divalent cycloaliphatic group, divalent aromatic group, divalent heterocyclic group, and combinations thereof. X ³ represents a hydrogen bonding group, and n3 is an integer of 0 or more.)

[3] The structural unit represented by the general formula (A) is represented by the general formula (I), and in the formula, R ¹ represents a hydrogen atom or a methyl group, and P ¹ represents —NR ¹² —. R ¹² represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms substituted by a hydrogen bonding group, and L ¹ is a substituted or unsubstituted divalent aromatic group, divalent heterocyclic group, and The retardation plate according to [2], which represents a divalent linking group selected from the group consisting of these combinations, X ¹ represents a hydrogen bonding group, and n1 is an integer of 1 to 4.
[4] The structural unit represented by the general formula (A) is represented by the general formula (I), in which R ¹ represents a hydrogen atom or a methyl group, P ¹ represents —NH—, L ¹ represents a divalent linking group selected from the group consisting of a substituted or unsubstituted divalent aromatic group and combinations thereof, X ¹ represents a hydrogen bonding group, and n1 is an integer of 1 to 3. The retardation plate according to [2].
[5] The structural unit represented by the general formula (A) is represented by the general formula (II), in which R ² represents a hydrogen atom or a methyl group, and L ²¹ is substituted or unsubstituted. Represents a divalent aromatic group or a divalent heterocyclic group, and P ²¹ is a divalent linkage selected from the group consisting of —O—, —NR ²¹ —, —CO—, —SO ₂ — and combinations thereof. R ²¹ represents a hydrogen atom or a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, L ²² represents a substituted or unsubstituted divalent aromatic group, divalent heterocyclic group, and The retardation plate according to [2], which represents a divalent linking group selected from the group consisting of those combinations, X ² represents a hydrogen bonding group, and n2 is an integer of 0 to 3.
[6] The structural unit represented by the general formula (A) is represented by the general formula (III), and in the formula, L ³¹ is a substituted or unsubstituted divalent aromatic group or divalent hetero group. Represents a cyclic group, P ³¹ represents a divalent linking group selected from the group consisting of —O—, —NR ³¹ —, —CO—, —SO ₂ — and combinations thereof, and R ³¹ represents a hydrogen atom or carbon. 2 represents a substituted or unsubstituted alkyl group having 1 to 6 atoms, and L ³² is selected from the group consisting of a substituted or unsubstituted divalent aromatic group, a divalent heterocyclic group, and combinations thereof. The retardation plate according to [2], which represents a valent linking group, X ³ represents a hydrogen bonding group, and n3 is an integer of 0 to 3.
[7] Of [1] to [6], X, X ¹ , X ² and X ³ are each a hydrogen bonding group selected from —CO ₂ H, —SO ₂ NH ₂ and —CONH ₂ . One of the phase difference plates.
[8] The molecule according to any one of [1] to [7], wherein the molecules of the rod-like smectic A liquid crystalline compound have their major axes aligned substantially perpendicular to the rubbing direction of the alignment film. Phase difference plate.
[9] The support has a longitudinal direction, the rubbing direction of the alignment film is parallel to the longitudinal direction of the support, and the molecules of the rod-like smectic A liquid crystalline compound have the long axis. The phase difference plate according to any one of [1] to [7], which is oriented so as to be substantially orthogonal to the longitudinal direction.

[10] A composition containing a polymer containing a structural unit represented by the general formula (A) is applied to the surface of a support having a longitudinal direction to form a layer, and the surface of the layer is A step of forming an alignment film by rubbing in parallel with the longitudinal direction, and a composition containing a rod-like smectic A liquid crystal compound is applied to the rubbing-treated surface of the alignment film so that molecules of the rod-like smectic A liquid crystal compound are And a step of forming an optically anisotropic layer by aligning the major axis substantially perpendicular to the rubbing direction and fixing the alignment in the aligned state.
[11] A polarizing plate having the retardation plate of any one of [1] to [9] and a polarizing film.
[12] The polarizing plate according to [11], wherein the slow axis of the optically anisotropic layer and the absorption axis of the polarizing film are substantially perpendicular to each other.
[13] Two polarizing films whose absorption axes are orthogonal to each other, and a liquid crystal layer composed of a pair of substrates and liquid crystal molecules sandwiched between the two polarizing films between the two polarizing films A liquid crystal cell in which the liquid crystalline molecules are aligned in a direction substantially perpendicular to the substrate in a non-driving state in which no external electric field is applied; and optically positive refractive index anisotropy; A second optically anisotropic layer having an optically negative refractive index anisotropy, Re of 0 to 10 nm, and Rth of 60 to 250 nm. A liquid crystal display device having at least one optically anisotropic layer, wherein the first optically anisotropic layer is the optically anisotropic layer according to any one of [1] to [9] Display device.
[14] In the first optically anisotropic layer, rod-like smectic A liquid crystalline molecules are horizontally aligned with their major axis substantially orthogonal to one of the absorption axes of the two polarizing films. The liquid crystal display device according to [13].
[15] The liquid crystal display device according to [13] or [14], wherein the second optically anisotropic layer is a layer formed of discotic liquid crystal molecules that are substantially horizontally aligned.

  In the present specification, “substantially” for the angle means that the angle is within a range of a strict angle ± 10 ° or less. The error from the exact angle is preferably 5 ° or less, and more preferably 3 ° or less. That is, two axes being substantially parallel means that the angle formed by the other axis with respect to one axis is 0 ° or more and 10 ° or less, and preferably 5 ° or less. The following is more preferable. “Two axes are substantially perpendicular” means that the angle formed by the other axis with respect to one axis is 80 ° or more and 100 ° or less, preferably 85 ° or more and 95 ° or less, and 87 It is more preferable that the angle is not less than ° and not more than 93 °. Further, the “slow axis” means a direction in which the refractive index is maximized. Further, the measurement wavelength of the refractive index is a value at λ = 550 nm in the visible light region unless otherwise specified. In this specification, “visible light” means 400 nm to 700 nm, and the measurement wavelength of the refractive index is a value at λ = 550 nm in the visible light region unless otherwise specified. In this specification, “polarizing film” and “polarizing plate” are distinguished from each other, and “polarizing plate” is a laminate having a transparent protective film for protecting the polarizing film on at least one side of the “polarizing film”. Means. In the present specification, the description “(numerical value 1) to (numerical value 2)” means “(numerical value 1) or more and (numerical value 2) or less”.

In the present specification, Re and Rth respectively represent in-plane retardation and retardation in the thickness direction at a wavelength of 550 nm. Re (λ) is measured by making light having a wavelength of 550 nm incident in the normal direction of the film in KOBRA 21ADH (manufactured by Oji Scientific Instruments). Rth was measured by making light having a wavelength of 550 nm incident from the direction inclined by + 40 ° with respect to the normal direction of the film with the slow axis in the plane (determined by KOBRA 21ADH) as the tilt axis (rotation axis). The retardation value and the retardation value measured by injecting light having a wavelength of 550 nm from a direction inclined by −40 ° with respect to the film normal direction with the in-plane slow axis as the tilt axis (rotation axis). KOBRA 21ADH is calculated based on the retardation value measured in the direction. Here, as the assumed value of the average refractive index, values in the polymer handbook (John Wiley & Sons, Inc.) and catalogs of various optical films can be used. Those whose average refractive index is not known can be measured with an Abbe refractometer. Examples of the average refractive index values of main optical films are given below:
Cellulose acylate (1.48), cycloolefin polymer (1.52), polycarbonate (1.59), polymethyl methacrylate (1.49), and polystyrene (1.59).
The KOBRA 21ADH calculates nx, ny, and nz by inputting the assumed value of the average refractive index and the film thickness. Nz = (nx−nz) / (nx−ny) is further calculated from the calculated nx, ny, and nz.

  According to the present invention, a rod-like smectic A liquid crystal compound can be aligned with its major axis substantially perpendicular to the rubbing direction without unevenness within the temperature range showing the smectic A liquid crystal phase. By using the optically anisotropic layer produced by the above, it is possible to contribute to the improvement of viewing angle characteristics of a liquid crystal display device, particularly a vertically aligned nematic liquid crystal display device.

BEST MODE FOR CARRYING OUT THE INVENTION

1. Retardation plate The retardation plate of the present invention is an alignment film containing the alignment film polymer on a support, and the alignment is controlled within the temperature range in which the smectic A liquid crystal phase is exhibited by the alignment film. It has an optically anisotropic layer containing a fixed rod-like smectic A liquid crystalline compound. FIG. 2 is a side view (a) schematically showing an embodiment of the retardation plate of the present invention (a side view seen from a direction perpendicular to the longitudinal direction) and a top view (b) (an optically anisotropic layer). 3 is a top view as seen from the 03 side). A retardation plate 05 shown in FIG. 2 has an alignment film 02 and an optically anisotropic layer 03 on a transparent support 01. The alignment film 02 can be formed on the surface of the transparent support 01 such as a plastic film by coating or vapor deposition. After rubbing the surface of the alignment film 02, when a composition (coating liquid) containing a rod-like smectic A liquid crystal compound is applied to the rubbing treatment surface, the molecules 04 of the rod-like smectic A liquid crystal compound are orientation-controlled by the rubbing direction, Orient to a desired orientation angle. Thereafter, liquid crystal molecules are fixed in the alignment state to form the optically anisotropic layer 03, and the retardation film 05 is obtained. In the present invention, by using a polymer having a structural unit represented by the general formula (A) described later as the material of the alignment film 02, as shown in the top view (b), the rod-like smectic A liquid crystalline molecule 04 is obtained. Can be stably oriented without unevenness so that the major axis thereof is substantially perpendicular to the rubbing direction. As a result, it is possible to provide a retardation plate that has an optical compensation capability that can support various modes including the VA mode and contributes to an improvement in the viewing angle of the liquid crystal display device.

Hereinafter, the alignment film and the optically anisotropic layer used in the retardation plate of the present invention will be described in detail.
(1) Alignment Film In the present invention, the alignment film contains a polymer having at least one structural unit represented by the following general formula (A) (hereinafter sometimes referred to as “polymer for alignment film”).

  In the formula, Mp represents a (2 + n) -valent linking group bonded to L at n sites, L represents a (1 + n) -valent linking group, n represents 1 or 2, and X represents a hydrogen bond Represents a sex group. However, the formula weight of the structural unit represented by the general formula (A) is 110 or more.

Hereinafter, Mp, L, and X will be described in detail.
Mp in the general formula (I) is a linking group that is the main chain of the polymer that forms the alignment film, and (2 + n) valence that binds to L that is the linking group with the hydrogen bonding group X at n sites. The linking group of In the formula, as the linking group which is the main chain of the polymer of Mp, a linking group consisting of only a carbon-carbon bond (for example, a substituted or unsubstituted ethylene linking group, butylene linking group, vinylene linking group, cyclic alkylene linking group, Phenylene linking groups, etc.), linking groups containing oxygen atoms (eg ether linking groups, acetal linking groups, ester linking groups, carbonate linking groups etc.), linking groups containing nitrogen atoms (eg amino linking groups, imino linking groups, Amide linking group, urethane linking group, ureido linking group, imide linking group, imidazole linking group, oxazole linking group, pyrrole linking group, anilide linking group, maleinimide linking group, etc.), linking group containing sulfur atom (for example, sulfide linking group) Groups, sulfone linking groups, thiophene linking groups, etc.), linking groups containing phosphorus atoms (eg phosphine linking groups, phosphates Such as Le linking group), a linking group (e.g. containing a silicon atom, a linking group such as a siloxane linking group), and a linking group formed by linking two or more of these and the like.
In addition, Mp in the formula is a (2 + n) -valent linking group derived from these divalent linking groups so that it can bind to L at n sites.

  Although the preferable specific example of Mp is shown below, this invention is not restrict | limited at all by the following specific example. Moreover, in the following specific examples, a site represented by * represents a site linked to L.

  The (2 + n) -valent linking group Mp is preferably a linking group consisting of only a carbon-carbon bond or a group derived from a linking group containing a nitrogen atom, and more preferably a substituted or unsubstituted ethylene linkage. A group derived from a group (eg, P-1, P-2, etc.), an imide linking group (eg, P-13), an amide linking group (eg, P-14) or a maleimide linking group (eg, P-19). And most preferably P-1, P-2 or P-19 which is a substituted or unsubstituted ethylene linking group.

The (1 + n) -valent linking group L that links Mp in the general formula (A) and the hydrogen bonding group X is a substituted or unsubstituted alkylene group having 1 to 20 carbon atoms (for example, methylene group, ethylene Group, propylene group, butylene group, isopropylene group, etc.), substituted or unsubstituted C2-C20 alkenylene group (for example, vinylene group, butene group, etc.), substituted or unsubstituted arylene group (for example, o- Phenylene group, m-phenylene group, p-phenylene group, 1,4-naphthylene group, etc.), —O—, —NR ¹ —, —S—, —PR ² —, —Si (R ³ ) (R ⁴ ) -, - C (= O) -, - C (= O) O -, - C (= O) NR 5 -, - OC (= O) O -, - OC (= O) NR 6 -, - NR ⁷ C (═O) NR ⁸ —, (—O) ₂ CH— and the like. R ^{1 to} R ⁸ represent a hydrogen atom or a substituent, for example, a hydrogen atom, a halogen atom, an alkyl group (including a cycloalkyl group such as a cycloalkyl group or a bicycloalkyl group), a substituted or unsubstituted alkenyl. Groups (including cycloalkenyl groups such as cycloalkenyl groups and bicycloalkenyl groups), alkynyl groups, aryl groups, heterocyclic groups, cyano groups, hydroxyl groups, nitro groups, carboxyl groups, alkoxy groups, aryloxy groups, silyloxy groups, Heterocyclicoxy group, acyloxy group, carbamoyloxy group, alkoxycarbonyloxy group, aryloxycarbonyloxy, amino group (including anilino group), acylamino group, aminocarbonylamino group, alkoxycarbonylamino group, aryloxycarbonylamino group, Sulfamoy Amino group, alkyl and arylsulfonylamino group, mercapto group, alkylthio group, arylthio group, heterocyclic thio group, sulfamoyl group, sulfo group, alkyl and arylsulfinyl group, alkyl and arylsulfonyl group, acyl group, aryloxycarbonyl group, Examples include alkoxycarbonyl group, carbamoyl group, aryl and heterocyclic azo group, imide group, phosphino group, phosphinyl group, phosphinyloxy group, phosphinylamino group and silyl group. Further, it may be any group selected from the following (1 + n) -valent linking group group I formed by linking two or more of these linking groups.

In the general formula (A), L represents an alkylene group having 1 to 3 carbon atoms, a phenylene group, —O—, —C (═O) —, —C (═O) O—, —C (═O). NH—, (—O) ₂ CH—, —OC (═O) NH—, L-1 or L-2 selected from the above linking group group is preferable, and a phenylene group, L-1 or L-2 is preferred. It is more preferable that

  In addition, as a preferable combination of Mp and L in the general formula (A), when Mp represents P-1 or P-2, L is a phenylene group, -O-, -C (= O) O. -, -C (= O) NH-, L-1 or L-2 are preferred, and when P represents P-19, L is preferably a phenylene group.

  The hydrogen bonding group X in the general formula (A) is preferably a group containing at least one —OH group or —NH group, for example, a hydroxyl group (—OH), a carboxyl group (—COOH). Carbamoyl group (—CONHR), sulfamoyl group (—SONHR), ureido group (—NHCONHR), amino group (—NHR), urethane group (—NHCOOR), and amide group (—NHCOR) are more preferred. However, R represents a hydrogen atom, a hydroxy group, an amino group, an alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 15 carbon atoms, or a heterocyclic group, and preferably represents a hydrogen atom. The hydrogen bonding group X in the general formula (A) is more preferably a hydroxyl group, a carboxyl group, a carbamoyl group, a sulfamoyl group or a ureido group, and most preferably a carboxyl group.

  In addition, the hydrogen atom contained in the hydrogen bonding group X in the general formula (A) may be dissociated and substituted with another cation. Preferred substituents include, for example, alkyl metals (Li, Na, K), alkyl earth metals (Ca, Mg, etc.), substituted or unsubstituted ammonium (eg, tetramethylammonium, triethylammonium, diisopropylethylammonium, unsubstituted ammonium, etc.).

  In addition, the formula weight of the structural unit represented by the general formula (A) is 110 or more. The formula weight is preferably 160 to 1000, and more preferably 190 to 700. If the formula weight is less than 110, the regulating force for aligning the rod-like smectic A liquid crystal molecules in the direction perpendicular to the rubbing direction becomes weak, and this tends to align in the direction parallel to the rubbing direction. .

  In this invention, it is preferable that the polymer for alignment films contains the structural unit represented by either the following general formula (I), general formula (II), and general formula (III).

In the formula, R ¹ represents a hydrogen atom, a methyl group, a halogen atom or a cyano group, P ¹ represents an oxygen atom, —CO— or —NR ¹² —, and R ¹² represents a hydrogen atom, which has 1 to 6 carbon atoms. Represents a substituted or unsubstituted alkyl group or a substituted or unsubstituted aryl group having 6 or more carbon atoms, and L ¹ is a substituted or unsubstituted alkylene group, divalent cycloaliphatic group, divalent aromatic Represents a divalent linking group selected from the group consisting of a group, a divalent heterocyclic group and a combination thereof, X ¹ represents a hydrogen bonding group, and n1 represents an integer of 1 or more.

In the formula, R ² represents a hydrogen atom, a methyl group, a halogen atom or a cyano group, L ²¹ represents a substituted or unsubstituted divalent aromatic group or a divalent heterocyclic group, and P ²¹ represents a single bond. ^{, -O -, - NR 21 -} , - CO -, - S -, - SO -, - SO 2 - and represents a divalent linking group selected from the group consisting of, R ²¹ is a hydrogen atom or Represents a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, and L ²² represents a substituted or unsubstituted alkylene group, divalent cycloaliphatic group, divalent aromatic group, divalent heterocyclic group. And a divalent linking group selected from the group consisting of these, X ² represents a hydrogen bonding group, and n2 is an integer of 0 or more.

In the formula, L ³¹ represents a substituted or unsubstituted divalent aromatic group or divalent heterocyclic group, and P ³¹ represents a single bond, —O—, —NR ³¹ —, —CO—, —S—. , —SO—, —SO ₂ — and a divalent linking group selected from the group consisting of these, R ³¹ represents a hydrogen atom or a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, L ³² represents a substituted or unsubstituted divalent linking group selected from the group consisting of an alkylene group, a divalent cycloaliphatic group, a divalent aromatic group, a divalent heterocyclic group, and combinations thereof. , X ³ represents a hydrogen bonding group, and n3 is an integer of 0 or more.

Hereinafter, the general formula (I), the general formula (II), and the general formula (III) will be described in detail. First, in the general formula (I) for explaining the general formula (I), R ¹ represents a hydrogen atom, a methyl group, a halogen atom or a cyano group, preferably a hydrogen atom, a methyl group or a halogen atom, more preferably. Is a hydrogen atom or a methyl group. P ¹ represents an oxygen atom, —CO— or —NR ¹² —. R ¹² represents a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, or a substituted or unsubstituted aryl group having 6 or more carbon atoms, preferably a hydrogen atom or 1 to 4 carbon atoms. An alkyl group, more preferably a hydrogen atom, a methyl group or an ethyl group.

L ¹ represents a divalent linking group selected from the group consisting of a substituted or unsubstituted alkylene group, divalent cycloaliphatic group, divalent aromatic group, divalent heterocyclic group, and combinations thereof. To express. As the alkylene group, an alkylene group having 1 to 10 carbon atoms is preferable, and an alkylene group having 1 to 6 carbon atoms is more preferable. For example, a methylene group, an ethylene group, a trimethylene group, etc. are mentioned. As the divalent cycloaliphatic group, cyclohexane-1,2-diyl, 1,4-cyclohexane-1,4-diyl, and cyclobutane-1,3-diyl are preferable, and 1,4-cyclohexane-1 is more preferable. , 4-diyl, cyclobutane-1,3-diyl. Examples of the aromatic ring contained in the divalent aromatic group include a benzene ring, an indene ring, a naphthalene ring, a fluorene ring, a phenanthrene ring or an anthracene ring, and a benzene ring or a naphthalene ring is preferable. Examples of the divalent aromatic group include 1,4-phenylene, 1,3-phenylene, 1,2-phenylene, 1,2-naphthylene, 1,3-naphthylene, 1,4-naphthylene, and 1,5-naphthylene. 1,8-naphthylene and 2,6-naphthylene are preferable, and 1,4-phenylene, 1,3-phenylene, 1,4-naphthylene, 1,5-naphthylene and 2,6-naphthylene are more preferable. The heterocycle contained in the divalent heterocyclic group is preferably a 5-membered, 6-membered or 7-membered heterocycle, and more preferably a 5-membered or 6-membered ring.
The hetero atom constituting the hetero ring is preferably at least one selected from a nitrogen atom, an oxygen atom and a sulfur atom. Examples of heterocycles include furan ring, thiophene ring, pyrrole ring, pyrrolidine ring, oxadiazole ring, isoxadiazole ring, thiazole ring, isothiazole ring, imidazole ring, imidazoline ring, imidazolidine ring, pyrazole ring, Pyrazoline ring, pyrazolidine ring, triazole ring, furazane ring, pyran ring, thiyne ring, oxadiazole ring, thiadiazole ring, pyridine ring, piperidine ring, oxazine ring, morpholine ring, thiazine ring, pyridazine ring, pyrimidine ring, pyrazine ring, Examples of the divalent hetero group containing a piperazine ring and a triazine ring include pyridine-2,5-diyl, pyridine-2,4-diyl, pyrimidine-2,5-diyl, pyrimidine-2,4-diyl, 1,3,5-triazine-2,4-diyl is preferred. Furthermore, the alkylene group, divalent cycloaliphatic group, divalent aromatic group, and divalent heterocyclic group may have a substituent. Examples of the substituent include an aliphatic group, aromatic Group, heterocyclic group, halogen atom, alkoxy group (eg methoxy, ethoxy, methoxyethoxy), aryloxy group (eg phenoxy) arylazo group (eg phenylazo), alkylthio group (eg methylthio, ethylthio, propylthio), Alkylamino groups (eg methylamino, propylamino), arylamino groups (eg phenylamino), acyl groups (eg formyl, acetyl, propanoyl, octanoyl, benzoyl), acyloxy groups (eg acetoxy, pivaloyloxy, benzoyloxy) ), Hydroxy group, mercapto group, amino group, cal Hexyl group, a sulfo group, a carbamoyl group, a sulfamoyl group, include ureido group.

In the general formula (I), X ¹ has the same meaning as the hydrogen bonding group represented by X in the general formula (A), and the preferred range is also the same. n1 represents an integer of 1 or more, but an integer of 1 to 3 is preferable.

Next, general formula (II) will be described.
In the general formula (II), R ² has the same meaning as R ¹ in the general formula (I), and the preferred range is also the same. L ²¹ represents a substituted or unsubstituted divalent aromatic group or divalent heterocyclic group, and the divalent aromatic group or divalent heterocyclic group represented by L ^{1 in the} general formula (I) It is synonymous and the preferable range is also the same. P ²¹ represents a divalent linking group selected from the group consisting of a single bond, —O—, —NR ²¹ —, —CO—, —S—, —SO—, —SO ₂ —, and combinations thereof; ²¹ has the same meaning as R ^{12 in} formula (I), and the preferred range is also the same. L ²² represents a substituted or unsubstituted divalent linking group selected from the group consisting of an alkylene group, a divalent cycloaliphatic group, a divalent aromatic group, a divalent heterocyclic group, and combinations thereof. . For each group L ²² represents the same meaning as each of the groups L ¹ represents a Formula (I), and preferred ranges are also the same. X ² represents a hydrogen bonding group and has the same meaning as X in formula (A), and the preferred range is also the same. n2 represents an integer of 0 or more, but is preferably an integer of 0 to 3.

Next, general formula (III) will be described.
In the general formula (III), L ³¹ represents a substituted or unsubstituted divalent aryl group or divalent heterocyclic group, and the divalent aryl group represented by L ¹ in the general formula (I) or It is synonymous with a bivalent heterocyclic group, and its preferable range is also the same. P ³¹ represents a divalent linking group selected from the group consisting of a single bond, —O—, —NR ³¹ —, —CO—, —S—, —SO—, —SO ₂ —, and combinations thereof; ³¹ has the same meaning as R ¹² in formula (I), and the preferred range is also the same. L ³² represents a substituted or unsubstituted divalent linking group selected from the group consisting of an alkylene group, a divalent cycloaliphatic group, a bicyclic aromatic group, a divalent heterocyclic group, and combinations thereof. , L ³² is the same as each group represented by L ¹ in the general formula (I), and the preferred range is also the same. X ³ represents a hydrogen bonding group and has the same meaning as X in the general formula (A), and the preferred range is also the same. n3 represents an integer of 0 or more, and is preferably an integer of 0 to 3.

  Specific examples of the repeating unit represented by the general formula (I), the general formula (II) or the general formula (III), which are preferred embodiments of the general formula (A), are shown below. It is not limited at all.

  In the present invention, as the alignment film polymer, a homopolymer consisting of only one of the structural units represented by any one of the general formula (A), general formula (I), (II) and (III) may be used. In addition, a polymer comprising a combination of two or more structural units represented by any one of the general formula (A), general formula (I), (II) and (III) may be used, or the general formula ( A) A polymer composed of a combination of one or more structural units represented by any one of the general formulas (I), (II) and (III) and one or more other structural units may be used. Good. The structural unit other than the structural unit represented by general formula (A), general formula (I), (II) or (III) is not particularly limited as long as it is copolymerizable, but is preferably a copolymerization structure. Units include, for example, vinyl monomers (for example, acrylic acid, methacrylic acid, acrylic esters, methacrylic esters, acrylic amides, methacrylic amides, vinyl alcohol, acyloxyvinyls, styrenes, maleic acid , Maleic esters, maleamides, acrylonitrile, vinyl alkyl ketones, etc.) and the structural units obtained by sequential polymerization, and represented by the following general formula (IV-A) or general formula (IV-B) Structural units.

In the general formula (IV-A), R ⁴¹ has the same meaning as R ¹ in Formula (I), and also the same preferred ranges thereof. L ⁴¹ represents a single bond, —COO—, —OCO— or —CONHR ⁴² —, wherein R ⁴² represents a hydrogen atom, a hydrocarbon group having 1 to 10 carbon atoms or a heterocyclic group having 4 to 10 carbon atoms. To express. Preferred examples of the hydrocarbon group include methyl, ethyl, propyl, butyl, phenyl and the like. Preferred examples of the heterocyclic group include groups shown as the heterocyclic group represented by L ¹ in the general formula (I). These groups may have a substituent. Z in the general formulas (IV-A) and (IV-B) represents a hydrogen atom, a halogen atom (for example, chloro atom), an alkyl group (for example, methyl group, ethyl group, etc.), an aryl group (for example, phenyl). Group, naphthyl group, etc.), —OR ^{1 ′} , —NR ^{2 ′} R ^{3 ′} , —SR ^{4 ′} , —PR ^{5 ′} R ^{6 ′} , —SiR ^{7 ′} R ^{8 ′} R ^{9 ′} , —C (═O) R ^{10 ′} , —C (═O) OR ^{11 ′} , —C (═O) NR ^{12 ′} R ^{13 ′} , —OC (═O) OR ^{14 ′} , —OC (═O) NR ^{15 ′} R ^{16 ′} , ^{-NR 17 'C (= O)} NR 18' R 19 '-, (- O) 2 CHR 20', represents the ^{-N + R 21 'R 22'} R 23 ' or the like. R ^{1 ′ to} R ^{23 ′} have the same meaning as the group represented by R ⁴² .

  In the present invention, the alignment film polymer preferably has a water-soluble group (for example, hydroxyl group, carboxyl group, sulfo group, quaternary ammonium group, amino group, phospho group, etc.). Alternatively, it preferably has a carboxyl group. These water-soluble substituents may be substituents of the structural unit represented by the general formula (A), general formula (I), (II) or (III), or other structural units. It may be a substituent.

  Specific examples of the structural unit represented by the general formula (IV-A) or the general formula (IV-B) are shown below, but the present invention is not limited to the following specific examples.

  In the present invention, the total content of the structural units represented by the general formula (A), general formula (I), (II) or (III) in the alignment film polymer is 1% by mass or more and 100% by mass. % Is preferably 10% by mass to 100% by mass, and more preferably 20% by mass to 100% by mass.

  In the present invention, the alignment film polymer preferably further includes a structural unit having a crosslinkable group. When the alignment film polymer contains a polymerizable group, for example, when the liquid crystalline compound having a polymerizable group is aligned on the alignment film of the present invention and is fixed to the alignment state by polymerization on the alignment film, the alignment film It is often preferable that the adhesion between the layer and the optically anisotropic layer made of a fixed liquid crystal compound is improved. The crosslinkable group may be any of addition, condensation, substitution reactive group and the like, and is not particularly limited. On the other hand, as the liquid crystalline compound, a material having an ethylenically unsaturated group such as an acryloyl group or a methacryloyl group is preferably fixed by ultraviolet irradiation in the presence of a radical photopolymerization initiator. It is preferable that the polymer for use also has a crosslinkable group capable of undergoing a crosslinking reaction upon irradiation with ultraviolet rays. As a preferred example of a reaction that can be crosslinked by ultraviolet irradiation, a ring-opening polymerization reaction of a heterocyclic compound such as an epoxy ring or an oxetane ring that is combined with a compound that generates a cation by ultraviolet irradiation and a compound that generates a radical by ultraviolet irradiation are used in combination. The radical polymerization reaction of the compound which has an ethylenically unsaturated group is mentioned. Among these, the most preferable crosslinkable group contained in the polymer for alignment film is an ethylenically unsaturated group (for example, acryloyl group, methacryloyl group, styryl group, etc.). Moreover, there is no restriction | limiting in particular as a crosslinkable group introduction | transduction method in the polymer for said alignment films.

  Although the preferable specific example of the structural unit containing a crosslinkable group is shown below, this invention is not restrict | limited at all by the following specific examples.

  In the present invention, the polymer for alignment film can be produced by various methods such as addition, condensation, and substitution reaction. It is most convenient and preferable to produce by a radical polymerization reaction of an ethylenically unsaturated compound which is a structural unit represented by any one of the general formulas (A), (I), (II) and (III). On the other hand, when the alignment film polymer includes a structural unit having a crosslinkable group, the polymer directly polymerizes a corresponding monomer (that is, a monomer having a substituent that becomes a crosslinkable group), Synthesized by a method of introducing an ethylenically unsaturated group; or (b) a method of introducing an ethylenically unsaturated group into a polymer obtained by polymerizing a monomer having an arbitrary functional group by a polymer reaction. it can. The method (b) is preferred. The polymer reaction is performed by, for example, I) generating a polymer containing a functional group obtained by precuring an ethylenically unsaturated group that can remove hydrochloric acid from, for example, a 2-chloroethyl group, and then converting the functional group (elimination reaction, oxidation). A method of inducing an ethylenically unsaturated group by reaction, reduction reaction, deprotection reaction, etc.); and II) after forming a polymer containing any functional group, a bond formation reaction proceeds with the functional group in the polymer. And a method of reacting a compound having both a functional group capable of forming a covalent bond and an ethylenically unsaturated group (hereinafter referred to as “reactive monomer”). Further, the polymer may be synthesized by combining the methods I) and II). The bond formation reaction referred to here can be used without particular limitation as long as it is a reaction that forms a covalent bond in the bond formation reaction generally used in the field of organic synthesis. On the other hand, the ethylenically unsaturated group contained in the polymer may be thermally polymerized and gelled during the reaction, so that the reaction proceeds at the lowest possible temperature (preferably 60 ° C. or less, particularly preferably room temperature or less). Is preferred. A catalyst may be used for the purpose of promoting the progress of the reaction, and a polymerization inhibitor may be used for the purpose of suppressing gelation.

  When the alignment film polymer contains a repeating unit substituted with a crosslinkable group, the preferred ratio is 0.1 mass% or more and 60 mass% or less, more preferably 0.3 mass% or more and 50 mass% or less. Especially preferably, it is 0.5 mass% or more and 40 mass% or less.

  The preferred molecular weight range of the alignment film polymer used in the present invention is 1,000 to 1,000,000, more preferably 2,000 to 200,000 in terms of weight average molecular weight. Most preferably, it is 3000 or more and 100,000 or less.

  Although the preferable example of the polymer for alignment films used for this invention below is shown in Table 1, this invention is not limited to this. In addition, the structural unit represented by the general formula (A), the general formula (I), (II) or (III), and the structural unit containing a crosslinkable substituent are the specific examples given above. It represents with the number of the example, and added the copolymerization composition ratio in the mass%.

  The alignment film polymer can be easily synthesized by a known method. Specific examples of synthesis of the alignment film polymer will be described below, but the synthesis examples are not limited thereto.

Synthesis example of (AL-1) N, N-dimethylacetamide (300 ml) was added to a 500 mL three-necked flask to dissolve 4-aminobenzoic acid (40.3 g, 0.294 mol) and cooled to 0 ° C. Acrylic acid chloride (30.0 g, 0.331 mol) was slowly added dropwise. After completion of the dropwise addition, the reaction solution was heated to 40 ° C., and further heated and stirred for 2 hours. Then, the reaction solution was added to 3 L of water, and the precipitated solid was separated by filtration under reduced pressure and dried by blowing (intermediate A). Was obtained quantitatively. N, N-dimethylformamide (10 ml) was placed in a 100 mL three-necked flask, heated to 65 ° C. while flowing nitrogen at a flow rate of 35 ml / min, and an initiator (V-65, 7 manufactured by Wako Pure Chemical Industries, Ltd.) was used. 0.5 mg) of N, N-dimethylformamide (4 ml) was added. After 10 minutes, an intermediate A (7.5 g: 0.039 mol) and an initiator (V-65, Wako Pure Chemical Industries, Ltd. V-65, 18.5 mg) in N, N-dimethylformamide (20 ml) were added for 3 hours. After completion of the addition, an N, N-dimethylformamide (2 ml) solution of an initiator ((Wako Pure Chemical Industries, Ltd., V-65, 3.8 mg)) was added and reacted at that temperature for 3 hours. Thereafter, the reaction system was returned to room temperature, and then slowly poured into stirred water (800 mL), and the precipitated polymer was taken out by suction filtration and further dried. The polymer was dried to obtain 6.9 g of an alignment film (AL-1) used in the present invention, and it was confirmed by ¹ H-NMR that the obtained solid was a polymer. .

  In the present invention, the alignment film is formed by applying a coating solution prepared by dissolving the polymer for alignment film in a solvent to the support surface, and drying and removing the solvent contained in the coating solution at 25 ° C to 140 ° C. Can be produced. Moreover, although it can also form by vapor deposition if possible, formation by application | coating is more preferable. The thickness of the alignment film thus formed is preferably 0.01 to 5 μm, and more preferably 0.05 to 2 μm.

  Examples of the solvent used for the preparation of the alignment film forming coating solution include water, alcohols (eg, methanol, ethanol, isopropanol, etc.), amides (eg, N, N-dimethylformamide, etc.), acetonitrile, acetone. , Methyl ethyl ketone, methyl isobutyl ketone, ethyl acetate, and the like, preferably water, alcohols, and mixed solvents thereof. The concentration of the alignment film polymer in the coating solution is preferably 0.1% by mass to 40% by mass, more preferably 0.5% by mass to 20% by mass, and 2% by mass to 10% by mass. % Is more preferable. The viscosity of the coating solution is preferably 0.1 cp to 100 cp, and more preferably 0.5 cp to 50 cp.

  In addition to the alignment film polymer, an additive may be appropriately added to the coating solution. For example, when the alignment film polymer is difficult to dissolve in a water-soluble solvent, a basic compound (for example, sodium hydroxide, lithium hydroxide, triethylamine) or an acidic compound (for example, hydrochloric acid, acetic acid, succinic acid, etc.) ) May be added to promote dissolution.

  The alignment film formed by the above method is preferably given a liquid crystal alignment by rubbing the surface. The rubbing treatment can be carried out by rubbing the surface of the polymer coating layer with paper or cloth in a certain direction (usually the longitudinal direction) several times. In particular, in the present invention, “Liquid Crystal Handbook” (Maruzen Co., Ltd.) It is preferable to carry out by the method described in)). Regarding the rubbing method for the long film, the method described in paragraphs [0017] to [0027] of JP-A-9-166784 is also preferable. As a method other than rubbing, liquid crystal alignment can be imparted by applying an electric field, applying a magnetic field, or irradiating light. As a method for imparting liquid crystal alignment, an alignment film formed by a rubbing treatment of a polymer is particularly preferable.

  The alignment film thus prepared is suitable for aligning a rod-like smectic A liquid crystalline compound. As schematically shown in FIG. 2 (b), when a composition containing a rod-like smectic A liquid crystal compound is applied on the rubbing-treated surface of the alignment film 02, the molecules 04 of the rod-like smectic A liquid crystal compound are converted into its molecules 04. The major axis can be stably oriented substantially perpendicular to the rubbing direction applied to the surface of the alignment film 02. As a result, an optically anisotropic layer exhibiting optical anisotropy expressed by such an orientation state can be stably produced without unevenness, for example, optical anisotropy for optically compensating a VA mode liquid crystal cell. A layer can be produced stably.

(2) Optically anisotropic layer The optically anisotropic layer contains a rod-like smectic A liquid crystalline compound fixed in the orientation state of the smectic A liquid crystal phase. The optically anisotropic layer is formed by applying a coating liquid containing a rod-like smectic A liquid crystalline compound and, optionally, a polymerizable initiator and other additives onto the surface of the alignment film formed on a support, for example, It can be formed by aligning and fixing a smectic A liquid crystalline compound. After aligning and fixing the liquid crystalline compound, the support may be peeled off.

(2) -a Forming Method The optically anisotropic layer is formed on the support as described above, with the coating liquid prepared by dissolving the rod-like smectic A liquid crystalline compound in a solvent capable of being dissolved, and oriented. It can produce by apply | coating on the oriented film of this invention to which the property was provided. Further, if possible, formation by vapor deposition may be used, but formation by coating is preferably used. Examples of the coating method include known coating methods such as curtain coating, dip coating, spin coating, printing coating, spray coating, slot coating, roll coating, slide coating, blade coating, gravure coating, and wire bar method. Next, the solvent used at 25 ° C. to 130 ° C. is dried, and at the same time, the liquid crystalline compound is oriented and further fixed by ultraviolet irradiation or the like, thereby forming an optically anisotropic layer of the liquid crystalline compound. It is preferable to use ultraviolet rays for light irradiation for polymerization. The irradiation energy is preferably ^{20mJ / cm 2 ~50J / cm 2} , further preferably 100 to 800 mJ / cm ^2. In order to accelerate the photopolymerization reaction, light irradiation may be performed under heating conditions. The thickness of the optically anisotropic layer thus formed varies depending on the optimum retardation value depending on the application such as optical compensation, but is preferably 0.1 to 10 μm, preferably 0.5 to 5 μm. More preferably.

(2) -b Material used for forming optically anisotropic layer A rod-like smectic A liquid crystalline compound is used for forming the optically anisotropic layer.
In this specification, the smectic phase refers to a state in which molecules aligned in one direction have a layer structure. In addition, from the viewpoint that each layer faces the same direction, a liquid crystalline compound having a smectic A phase is preferable as described above.

  Here, the rod-like smectic A liquid crystal compound is a rod-like liquid crystal compound having a temperature range showing a smectic A liquid crystal phase, and other than the smectic A liquid crystal phase if the directionality of each layer constituting the smectic is in a desired range. Liquid crystal phase (for example, it may be a compound that also shows a smectic B phase, a smectic C phase, etc.).

In general, a rod-like liquid crystalline compound is composed of a rigid unit (usually called a mesogenic group) in which two or more rings such as an aromatic ring are connected, and hydrocarbon chains substituted at both ends, but the side chain portion. Due to subtle differences in the hydrocarbon chain, the type of liquid crystal phase and the phase transition temperature change very sensitively.
In the case of having the same mesogenic group, the longer the hydrocarbon chain, the more generally it shows a smectic phase.

  The mesogenic group of the rod-like smectic A liquid crystal compound includes azomethines, azoxybenzene groups, biphenyl groups, phenyl ester groups, benzoic acid ester groups, cyclohexanecarboxylic acid phenyl ester groups, phenylcyclohexane groups, phenylpyrimidine groups, and phenyldioxane groups. , Etc. are preferably used.

  Preferred mesogenic groups exhibiting a smectic A phase include biphenyl groups, benzoic acid ester groups, and phenylpyrimidine groups. More preferred mesogenic groups include tricyclic or more phenyl groups described in JP-A-11-322678. It is a benzoic acid ester group having.

  Moreover, as a hydrocarbon group substituted on both ends of the said mesogenic group required in order to express a smectic A phase, it is preferable that it is a C3-C20 hydrocarbon group, More preferably, it is C6-C14. It is a hydrocarbon group. Preferably, it is a compound represented by the following general formula (I).

^{(V) Q 1 -L 1 -Cy} 1 -L 2 - (Cy 2 -L 3) n -Cy 3 -L 4 -Q 2
In the formula, Q ¹ and Q ² are each independently a polymerizable group, L ¹ and L ⁴ are each independently a divalent linking group, and L ² and L ³ are each independently a single bond or a divalent group. It is a linking group, Cy ¹ , Cy ² and Cy ³ are each a divalent cyclic group, and n is 0, 1 or 2.

Hereinafter, the polymerizable rod-like smectic A liquid crystalline compound represented by the general formula (V) will be described. In the formula, Q ¹ and Q ² are each independently a polymerizable group. The polymerization reaction of the polymerizable group is preferably addition polymerization (including ring-opening polymerization) or condensation polymerization. In other words, the polymerizable group is preferably a functional group capable of addition polymerization reaction or condensation polymerization reaction. Examples of polymerizable groups are shown below.

L ¹ and L ⁴ are each independently a divalent linking group. L ¹ and L ⁴ are each independently two selected from the group consisting of —O—, —S—, —CO—, —NR ² —, a divalent chain group, a divalent cyclic group, and combinations thereof. A valent linking group is preferred. R ² is an alkyl group having 1 to 7 carbon atoms or a hydrogen atom. R ² is preferably an alkyl group having 1 to 4 carbon atoms or a hydrogen atom, more preferably a methyl group, an ethyl group or a hydrogen atom, and most preferably a hydrogen atom. The example of the bivalent coupling group which consists of a combination is shown below. Here, the left side is coupled to Q (Q ¹ or Q ² ), and the right side is coupled to Cy (Cy ¹ or Cy ³ ).

L-1: —CO—O—divalent chain group —O—
L-2: -CO-O-divalent chain group -O-CO-
L-3: —CO—O—divalent chain group —O—CO—O—
L-4: -CO-O-divalent chain group -O-divalent cyclic group-
L-5: -CO-O-divalent chain group -O-divalent cyclic group -CO-O-
L-6: -CO-O-divalent chain group -O-divalent cyclic group -O-CO-
L-7: -CO-O-divalent chain group-O-divalent cyclic group-divalent chain group-
L-8: -CO-O-divalent chain group -O-divalent cyclic group -divalent chain group -CO-O-
L-9: -CO-O-divalent chain group -O-divalent cyclic group -divalent chain group -O-CO-
L-10: —CO—O—divalent chain group—O—CO—divalent cyclic group—
L-11: -CO-O-divalent chain group -O-CO-divalent cyclic group -CO-O-
L-12: -CO-O-divalent chain group -O-CO-divalent cyclic group -O-CO-
L-13: —CO—O—Divalent chain group—O—CO—Divalent cyclic group—Divalent chain group—
L-14: -CO-O-divalent chain group -O-CO-divalent cyclic group -divalent chain group -CO-O-
L-15: -CO-O-divalent chain group-O-CO-divalent cyclic group-divalent chain group-O-CO-
L-16: —CO—O—divalent chain group—O—CO—O—divalent cyclic group—
L-17: -CO-O-divalent chain group -O-CO-O-divalent cyclic group -CO-O-
L-18: -CO-O-divalent chain group -O-CO-O-divalent cyclic group -O-CO-
L-19: —CO—O—Divalent chain group—O—CO—O—Divalent cyclic group—Divalent chain group—
L-20: -CO-O-divalent chain group -O-CO-O-divalent cyclic group -divalent chain group -CO-O-
L-21: -CO-O-divalent chain group -O-CO-O-divalent cyclic group -divalent chain group -O-CO-

The divalent chain group means an alkylene group, a substituted alkylene group, an alkenylene group, a substituted alkenylene group, an alkynylene group, or a substituted alkynylene group. An alkylene group, a substituted alkylene group, an alkenylene group and a substituted alkenylene group are preferred, and an alkylene group and an alkenylene group are more preferred.
The alkylene group may have a branch. The alkylene group preferably has 1 to 12 carbon atoms, more preferably 2 to 10 carbon atoms, and most preferably 2 to 8 carbon atoms. The alkylene part of the substituted alkylene group is the same as the above alkylene group. Examples of the substituent include a halogen atom.
The alkenylene group may have a branch. The alkenylene group preferably has 2 to 12 carbon atoms, more preferably 2 to 10 carbon atoms, and most preferably 2 to 8 carbon atoms. The alkenylene part of the substituted alkenylene group is the same as the above alkenylene group.
Examples of the substituent include a halogen atom.
The alkynylene group may have a branch. The alkynylene group preferably has 2 to 12 carbon atoms, more preferably 2 to 10 carbon atoms, and most preferably 2 to 8 carbon atoms. The alkynylene part of the substituted alkynylene group is the same as the above alkynylene group.
Examples of the substituent include a halogen atom.
Specific examples of the divalent chain group include ethylene, trimethylene, propylene, tetramethylene, 2-methyl-tetramethylene, pentamethylene, hexamethylene, octamethylene, 2-butenylene, 2-butynylene and the like.

The definition and examples of the divalent cyclic group are the same as those of Cy ¹ , Cy ² and Cy ³ described later.

L ² and L ³ are each independently a single bond or a divalent linking group. L ² and L ³ are each independently two selected from the group consisting of —O—, —S—, —CO—, —NR ² —, a divalent chain group, a divalent cyclic group, and combinations thereof. A valent linking group or a single bond is preferred.
R ² is an alkyl group having 1 to 7 carbon atoms or a hydrogen atom, preferably an alkyl group having 1 to 4 carbon atoms or a hydrogen atom, and preferably a methyl group, an ethyl group, or a hydrogen atom. More preferably, it is a hydrogen atom. The divalent chain group and the divalent cyclic group have the same definitions as L ¹ and L ⁴ .

In the formula (V), n is 0, 1 or 2. When n is 2, two L ³ may be the same or different, and two Cy ² may be the same or different. n is preferably 1 or 2, and more preferably 1.

In the formula (V), Cy ¹ , Cy ² and Cy ³ are each independently a divalent cyclic group.
The ring contained in the cyclic group is preferably a 5-membered ring, a 6-membered ring or a 7-membered ring, more preferably a 5-membered ring or a 6-membered ring, and most preferably a 6-membered ring. The ring contained in the cyclic group may be a condensed ring. However, it is more preferably a monocycle than a condensed ring. The ring contained in the cyclic group may be any of an aromatic ring, an aliphatic ring, and a heterocyclic ring. Examples of the aromatic ring include a benzene ring and a naphthalene ring. Examples of the aliphatic ring include a cyclohexane ring. Examples of the heterocyclic ring include a pyridine ring and a pyrimidine ring. As the cyclic group having a benzene ring, 1,4-phenylene is preferable. As the cyclic group having a naphthalene ring, naphthalene-1,5-diyl and naphthalene-2,6-diyl are preferable. The cyclic group having a cyclohexane ring is preferably 1,4-cyclohexylene. As the cyclic group having a pyridine ring, pyridine-2,5-diyl is preferable. The cyclic group having a pyrimidine ring is preferably pyrimidine-2,5-diyl. The cyclic group may have a substituent. Examples of the substituent include a halogen atom, a cyano group, a nitro group, an alkyl group having 1 to 5 carbon atoms, a halogen-substituted alkyl group having 1 to 5 carbon atoms, and an alkoxy group having 1 to 5 carbon atoms. , An alkylthio group having 1 to 5 carbon atoms, an acyloxy group having 2 to 6 carbon atoms, an alkoxycarbonyl group having 2 to 6 carbon atoms, a carbamoyl group, and an alkyl-substituted carbamoyl group having 2 to 6 carbon atoms And an acylamino group having 2 to 6 carbon atoms.

  Below, the example of the rod-shaped smectic A liquid crystalline compound which has a polymeric group represented by Formula (V) is shown. The present invention is not limited to these.

The rod-like smectic A liquid crystal molecule is preferably fixed while maintaining the alignment state. The fixation is polymerization of a polymerizable group (for example, Q ¹ and Q ² in the formula (V)) introduced into the liquid crystal molecule. It is preferable to carry out the reaction. For that purpose, it is preferable to contain a polymerization initiator in the coating solution. The polymerization reaction includes a thermal polymerization reaction using a thermal polymerization initiator, a photopolymerization reaction using a photopolymerization initiator, and EB curing using an electron beam. The polymerization reaction includes a thermal polymerization reaction using a thermal polymerization initiator and a photopolymerization reaction using a photopolymerization initiator, and a photopolymerization reaction is preferred. Examples of polymerization initiators that generate radicals by the action of light include α-carbonyl compounds (described in US Pat. Nos. 2,367,661 and 2,367,670), acyloin ether (described in US Pat. No. 2,448,828), α -Combination of hydrocarbon-substituted aromatic acyloin compound (described in US Pat. No. 2,722,512), polynuclear quinone compound (described in US Pat. Nos. 3,046,127 and 2,951,758), triarylimidazole dimer and p-aminophenyl ketone (Described in US Pat. No. 3,549,367), acridine and phenazine compounds (JP-A-60-105667, US Pat. No. 4,239,850) and oxadiazole compounds (described in US Pat. No. 4,212,970), acetophenone compounds , Benzoy Preferred are ether ether compounds, benzyl compounds, benzophenone compounds, thioxanthone compounds and the like. Examples of the acetophenone compound include 2,2-diethoxyacetophenone, 2-hydroxymethyl-1-phenylpropan-1-one, 4′-isopropyl-2-hydroxy-2-methyl-propiophenone, 2-hydroxy -2-methyl-propiophenone, p-dimethylaminoacetone, p-tert-butyldichloroacetophenone, p-tert-butyltrichloroacetophenone, p-azidobenzalacetophenone and the like. Examples of the benzyl compound include benzyl, benzyl dimethyl ketal, benzyl-β-methoxyethyl acetal, 1-hydroxycyclohexyl phenyl ketone and the like. Examples of the benzoin ether compounds include benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin-n-propyl ether, benzoin isopropyl ether, benzoin-n-butyl ether, and benzoin isobutyl ether. Examples of the benzophenone compounds include benzophenone, methyl o-benzoylbenzoate, Michler's ketone, 4,4′-bisdiethylaminobenzophenone, 4,4′-dichlorobenzophenone, and the like. Examples of the thioxanthone compound include thioxanthone, 2-methylthioxanthone, 2-ethylthioxanthone, 2-isopropylthioxanthone, 4-isopropylthioxanthone, 2-chlorothioxanthone, 2,4-diethylthioxanthone, and the like. Among such photosensitive radical polymerization initiators composed of aromatic ketones, acetophenone compounds and benzyl compounds are particularly preferable in terms of curing characteristics, storage stability, odor, and the like. The photosensitive radical polymerization initiators composed of these aromatic ketones can be used alone or in combination of two or more according to the desired performance. In addition to a polymerization initiator, a sensitizer may be used for the purpose of increasing sensitivity. Examples of the sensitizer include n-butylamine, triethylamine, tri-n-butylphosphine, thioxanthone and the like.

  Multiple photopolymerization initiators may be combined, and the amount used is preferably 0.01 to 20% by mass, more preferably 0.5 to 5% by mass, based on the solid content of the coating solution.

  In the coating liquid for forming the optically anisotropic layer, other additives such as the rod-like smectic A liquid crystalline compound and the photopolymerization initiator may be appropriately added. For example, a plasticizer, a monomer, a surfactant, a cellulose ester, an alignment controller, a chiral agent, and the like can be given. The addition amount of the alignment control agent is preferably 0.05% by mass to 10% by mass with respect to the liquid crystal compound in the liquid crystal composition to which the control agent is added. More preferably, it is 0.1 mass%-5 mass%.

In particular, in order to horizontally (homogeneously) align the rod-like smectic A liquid crystalline compound that is easily oriented in the vertical (homeotropic) orientation, it is preferable to use an alignment controller that induces the horizontal orientation on the air interface side.
Preferably, the alignment control agent for inducing horizontal alignment is preferably a triazine compound described in paragraphs [0015] to [0041] of JP-A No. 2004-279625, at least one fluorine atom at positions 1, 3, and 5 of the benzene ring. And a compound having a substituent having.

  As the solvent used for preparing the coating liquid for forming the optically anisotropic layer, an organic solvent is preferable. Examples of organic solvents include amides (eg, N, N-dimethylformamide), sulfoxides (eg, dimethyl sulfoxide), heterocyclic compounds (eg, pyridine), hydrocarbons (eg, toluene, hexane) alkyl halides (eg, Chloroform, dichloromethane), esters (eg, methyl acetate, butyl acetate), ketones (eg, acetone, 2-butanone, methyl isobutyl ketone, cyclohexanone), ethers (eg, tetrahydrofuran, 1,2-dimethoxyethane) and the like . Of these, alkyl halides and ketones are preferred. Two or more organic solvents may be used in combination.

  The solid concentration of the rod-like smectic A liquid crystalline compound and other additives in the coating solution is preferably 0.1% by mass to 60% by mass, more preferably 0.5% by mass to 50% by mass, and 2% by mass. -40 mass% is further more preferable. The viscosity of the coating solution is preferably 0.01 cp to 100 cp, and more preferably 0.1 cp to 50 cp.

(3) Support body The phase difference plate of this invention has a support body. The support is not necessarily the same as the support used at the time of production, and after the optically anisotropic layer is produced, it may be transferred from the temporary support used at the production to another support. The support used in the retardation plate of the present invention is preferably a polymer film that is transparent, has a small optical anisotropy, and a small wavelength dispersion. Here, that the support is transparent means that the light transmittance is 80% or more. Specifically, the small chromatic dispersion means that the ratio of Re400 / Re700 is preferably less than 1.2. Specifically, the small optical anisotropy means that in-plane retardation (Re) is preferably 20 nm or less, and more preferably 10 nm or less. The transparent support preferably has a roll-like or rectangular sheet-like shape, and the optically anisotropic layer can be laminated using the roll-like transparent support and then cut into a required size. preferable. Examples of the polymer include cellulose acylate, polycarbonate, polysulfone, polyethersulfone, polyacrylate and polymethacrylate. Cellulose acylate is preferred, cellulose acetate is more preferred, and triacetyl cellulose is most preferred. About manufacturing a cellulose acylate film using a non-chlorinated solvent, it is described in detail in JIII Journal of Technical Disclosure No. 2001-1745, and the cellulose acylate film described therein is also preferably used in the present invention. it can.

  The polymer film for the support is preferably formed by a solvent cast method. The thickness of the transparent support is preferably 20 to 500 μm, and more preferably 30 to 200 μm. In order to improve the adhesion between the transparent support and the layer (adhesive layer, alignment film or optically anisotropic layer) provided on the transparent support, surface treatment (eg, glow discharge treatment, corona discharge treatment, ultraviolet light ( UV) treatment, flame treatment, saponification treatment). An adhesive layer (undercoat layer) may be provided on the transparent support.

  The retardation plate of the present invention is used for various applications. It can be used as a polarizing plate by being laminated with an optical compensation sheet of a liquid crystal display device, a linearly polarizing film or a transparent protective film.

2. Polarizing plate It is preferable when a linear polarizing film or a transparent protective film is bonded to the retardation plate of the present invention to form a polarizing plate, and then used for an actual liquid crystal display element. In FIG. 3, the cross-sectional schematic diagram of one Embodiment of the polarizing plate of this invention is shown. A polarizing plate 08 shown in FIG. 3 has a linear polarizing film 07 laminated on the back surface of the transparent support 01 of the retardation plate 05 shown in FIG. In this configuration, the linear polarizing film 07 is sandwiched between the transparent protective films 06 and bonded together. In the present invention, as shown in the top view of FIG. 3B, the linear polarizing film 07 is laminated so that the transmission axis of the linear polarizing film 07 is orthogonal to the longitudinal direction of the transparent support 01, that is, the rubbing direction of the alignment film 02. Further, since the long axis of the rod-like smectic A liquid crystalline molecule 04 is oriented perpendicular to the rubbing direction of the alignment film 02, the linearly polarizing film 07 has its transmission axis as the rod-like smectic A. The liquid crystal molecules 04 are preferably bonded in a direction parallel to the major axis direction. Further, since the slow axis of the optically anisotropic layer 03 coincides with the long axis direction of the liquid crystalline molecules 04, the transmission axis of the linearly polarizing film 07 coincides with the slow axis of the optically anisotropic layer 03. It is preferable to laminate.

Below, the linearly polarizing film and transparent protective film used for this invention are demonstrated.
(1) Linearly polarizing film Examples of linearly polarizing films include iodine-based polarizing films, dye-based polarizing films using dichroic dyes, and polyene-based polarizing films. The iodine polarizing film and the dye polarizing film are generally produced using a polyvinyl alcohol film. The transmission axis of the polarizing film corresponds to a direction orthogonal to the film stretching direction. The transmission axis of the polarizing film is arranged so as to be substantially parallel to the long axis direction (slow axis) of the rod-like smectic A liquid crystal molecule. Usually, it is preferably laminated to the support side of the optically anisotropic layer, but may be laminated to the liquid crystalline molecular layer side if necessary.

(2) Transparent protective film A transparent protective film may be bonded to the optically anisotropic layer side of the retardation plate of the present invention. It is preferable to use a transparent polymer film. That the protective film is transparent means that the light transmittance is 80% or more. As the transparent protective film, generally a cellulose ester film, preferably a triacetyl cellulose film is used. The cellulose ester film is preferably formed by a solvent cast method. The thickness of the transparent protective film is preferably 20 to 500 μm, and more preferably 50 to 200 μm.

3. Liquid crystal display device The liquid crystal display device of the present invention includes at least a pair of polarizing plates, and a liquid crystal cell and an alignment film including the alignment film polymer between the pair of polarizing plates, and the alignment state is maintained. And at least one optically anisotropic layer containing a fixed rod-like smectic A liquid crystalline compound. In the liquid crystal display device of the present invention, liquid crystal cells having various display modes can be used as much as possible. As described above, the optical compensation sheet exhibiting the optical anisotropy expressed by the orientation of the liquid crystalline molecules is TN (Twisted Nematic), IPS (In-Plane Switching), FLC (Ferroelectric Liquid Crystal), OCB (Optically Compensatory Bend), STN (Super Twisted Nematic), VA (Vertically Aligned), ECB (Electrically Controlled Bi), Nb (Electron Controlled Bend), ECB (Electrically Controlled Bi) A corresponding one has already been proposed. However, the retardation plate and polarizing plate of the present invention can be suitably applied to a VA mode liquid crystal cell which will be described in detail below.

(1) VA mode liquid crystal cell In this invention, it is preferable that a liquid crystal cell is VA mode. That is, the liquid crystal cell used in the present invention is preferably a liquid crystal cell in which the liquid crystalline molecules are aligned in a direction substantially perpendicular to the substrate in a non-driven state where no external electric field is applied. The VA mode liquid crystal cell is formed by sealing liquid crystal molecules having negative dielectric anisotropy between upper and lower substrates whose opposite surfaces are rubbed. For example, by using liquid crystal molecules having Δn = 0.0813 and Δε = −4.6, a director indicating the alignment direction of the liquid crystal molecules, that is, a liquid crystal cell having a so-called tilt angle of about 89 ° can be manufactured. At this time, the thickness d of the liquid crystal layer can be about 3.5 μm. The brightness at the time of white display changes according to the magnitude of the product Δnd of the thickness d of the liquid crystal layer and the refractive index anisotropy Δn.
In order to obtain the maximum brightness, the thickness d of the liquid crystal layer is preferably in the range of 0.2 to 0.5 μm.

  A transparent electrode is formed inside the alignment film on the upper and lower substrates sandwiching the liquid crystal cell, but in a non-driving state where no driving voltage is applied to the electrodes, the liquid crystal molecules in the liquid crystal layer are substantially perpendicular to the substrate surface. As a result, the polarization state of the light passing through the liquid crystal panel hardly changes. As described above, since the absorption axis of the upper polarizing plate of the liquid crystal cell and the absorption axis of the lower polarizing plate are substantially orthogonal, light does not pass through the polarizing plate, and an ideal black display in the non-driven state. Is realized. On the other hand, in the driving state, the liquid crystal molecules are inclined in a direction parallel to the substrate surface, and the light passing through the liquid crystal panel changes the polarization state by the inclined liquid crystal molecules and passes through the polarizing plate. In other words, white display is obtained in the driving state.

  Here, since an electric field is applied between the upper and lower substrates, an example using a liquid crystal material having a negative dielectric anisotropy in which liquid crystal molecules respond perpendicularly to the electric field direction is shown. In the case where an electrode is disposed on one substrate and an electric field is applied in a lateral direction parallel to the substrate surface, a liquid crystal material having a positive dielectric anisotropy can be used. In addition, in the VA mode liquid crystal display device, the addition of a chiral material generally used in the TN mode liquid crystal display device is rarely used to degrade the dynamic response characteristics, but in order to reduce alignment defects. May be added.

  The features of the VA mode are high-speed response and high contrast. However, there is a problem that the contrast is high in the front but decreases in the oblique direction. During black display, the liquid crystal molecules are aligned perpendicular to the substrate surface. When observed from the front, the liquid crystal molecules have almost no birefringence, so the transmittance is low and a high contrast can be obtained. However, when observed obliquely, birefringence occurs in the liquid crystalline molecules. Further, the crossing angle of the upper and lower polarizing plate absorption axes is 90 ° perpendicular to the front, but is larger than 90 ° when viewed from an oblique direction. Because of these two factors, leakage light occurs in the oblique direction, and the contrast is lowered. In the present invention, in order to solve this problem, at least one first and second optically anisotropic layers are disposed.

  In the VA mode, liquid crystal molecules are tilted during white display, but the birefringence of the liquid crystal molecules when viewed from an oblique direction is different between the tilt direction and the opposite direction, resulting in differences in luminance and color tone. . In order to solve this, the liquid crystal cell is preferably multi-domain. Multi-domain refers to a structure in which a plurality of regions having different alignment states are formed in one pixel. For example, in a multi-domain VA mode liquid crystal cell, a plurality of regions in which tilt angles of liquid crystal molecules are different from each other when an electric field is applied exist in one pixel. In a multi-domain VA mode liquid crystal cell, the tilt angle of liquid crystal molecules due to application of an electric field can be averaged for each pixel, whereby the viewing angle characteristics can be averaged. In order to divide the orientation within one pixel, the electrode is provided with slits or protrusions, and the electric field direction is changed or the electric field density is biased. In order to obtain a uniform viewing angle in all directions, the number of divisions may be increased, but a substantially uniform viewing angle can be obtained by dividing into four or eight or more. In particular, it is preferable that the polarizing plate absorption axis can be set at an arbitrary angle when dividing into eight.

  Also, the liquid crystal molecules are difficult to respond at the alignment division region boundary. For this reason, in normally black display, since black display is maintained, a reduction in luminance becomes a problem. Adding a chiral agent to the liquid crystal material contributes to reducing the boundary region.

(2) Configuration of Liquid Crystal Display Device FIG. 4 shows a schematic diagram of one embodiment of the liquid crystal display device of the present invention. The liquid crystal display device 17 includes a liquid crystal cell 16 and a pair of an upper polarizing plate 08 and a lower polarizing plate 15 disposed on both sides of the liquid crystal cell 16. The upper polarizing plate 08 is the polarizing plate shown in FIG. 3, and has a configuration in which the linear polarizing film 07 and the transparent protective film 06 are laminated on the retardation film 05 of the present invention shown in FIG. The retardation film 05 of the present invention includes an optically anisotropic layer 03 containing a rod-like smectic A liquid crystalline compound fixed in an alignment state functioning as a first optically anisotropic layer. Compensates the liquid crystal cell 16 optically. On the other hand, the lower polarizing plate 15 is an optical material containing a transparent support 11, an alignment film 12 formed on the surface thereof, and a discotic liquid crystal compound in which the alignment is controlled by the alignment film and fixed in the alignment state. In this configuration, a retardation film 14 having an anisotropic layer 13 and a polarizing film 10 and a transparent protective film 09 are laminated on the back surface of the transparent support 11. The second optical anisotropic layer 13 exhibits predetermined optical characteristics, and optically compensates the liquid crystal cell 16 together with the first optical anisotropic layer 03. The liquid crystal cell 16 includes an upper electrode substrate, a lower electrode substrate, and liquid crystal molecules sandwiched between them. The liquid crystalline molecules are controlled to be aligned in a direction substantially perpendicular to the substrate in a non-driven state where no external electric field is applied, depending on the direction of rubbing treatment applied to the opposite surface of the electrode substrate. Yes. Further, the upper polarizing plate 08 and the lower polarizing plate 15 are laminated so that their absorption axes are substantially orthogonal.

  The first optically anisotropic layer 03 has an optically positive refractive index anisotropy and has a retardation (Re) of 40 to 150 nm with respect to visible light. On the other hand, the second optically anisotropic layer 13 has an optically negative refractive index anisotropy, Re is 0 to 10 nm or less, and Rth is 60 to 250 nm with respect to visible light. FIG. 4 shows an example in which the second optically anisotropic layer 13 is formed from a composition containing a discotic liquid crystalline compound. Regarding the material constituting the second optically anisotropic layer 13 Is not particularly limited, and may be formed using a liquid crystalline compound or a polymer film, and the number of constituent layers is not particularly limited. The layer is preferably formed using a discotic liquid crystalline compound, and preferably exhibits optical anisotropy expressed by molecular orientation of the discotic liquid crystalline compound. The first optical anisotropic layer 03 and the second optical anisotropic layer 13 eliminate the image coloring of the liquid crystal cell and contribute to the expansion of the viewing angle.

  In FIG. 4, when the upper side is the observer side, in FIG. 4, the first optical anisotropic layer 03 is formed between the observer-side polarizing film 07 and the observer-side liquid crystal cell 16 substrate. 2 shows a configuration in which the optically anisotropic layer 13 is disposed between the polarizing film 10 on the back side and the substrate for the back side liquid crystal cell 16, but the first optically anisotropic layer and the second optically anisotropic layer 13 are shown. Alternatively, the first and second optically anisotropic layers may be disposed between the viewer-side polarizing film and the viewer-side liquid crystal cell substrate. Or may be disposed between the polarizing film on the back side and the substrate for the back side liquid crystal cell. In such an embodiment, the second optical anisotropic layer may also serve as a support that is a constituent member of the first optical anisotropic layer.

  The liquid crystal display device of the present invention is not limited to the above configuration, and may include other members. For example, a color filter may be disposed between the liquid crystal cell and the polarizing film. In the transmissive liquid crystal display device, a backlight using a cold or hot cathode fluorescent tube, a light emitting diode, or an electroluminescent element as a light source can be disposed on the back surface. On the other hand, in the aspect of the reflective liquid crystal display device, only one polarizing plate is required on the observation side, and a reflective film is provided on the back surface of the liquid crystal cell or the inner surface of the lower substrate of the liquid crystal cell. Of course, it is also possible to provide a front light using the light source on the liquid crystal cell observation side. Further, a transflective type in which a transmissive portion and a reflective portion are provided in one pixel of the display device is also possible.

  The type of the liquid crystal display device of the present invention is not particularly limited, and includes any of image direct view type, image projection type, and light modulation type liquid crystal display devices. The present invention is effective for an active matrix liquid crystal display device using a three-terminal or two-terminal semiconductor element such as TFT or MIM. Of course, it is also effective in a passive matrix liquid crystal display device represented by STN type called time-division driving.

(3) Configuration of liquid crystal display device Optically anisotropic layer used in liquid crystal display device In the present invention, the first and second optically anisotropic layers eliminate image coloring of the liquid crystal display device and have a viewing angle of Contributes to expansion. In addition, when the support of the optically anisotropic layer also serves as a protective film for the polarizing plate, or the optically anisotropic layer also serves as the protective film for the polarizing plate, the number of constituent members of the liquid crystal display device can be reduced. Therefore, in this aspect, it contributes also to thickness reduction of a liquid crystal display device.

  In the present invention, the in-plane retardation (Re) of the first optically anisotropic layer with respect to visible light is 40 to 150 nm, preferably 50 to 120 nm. Re of the second optically anisotropic layer with respect to visible light is 0 to 10 nm or less, Rth is 60 to 250 nm or less, preferably Re is 0 to 5 nm, and Rth is 80 to 230 nm. Since the first and second optically anisotropic layers exhibit an optical compensation function as a whole by their combination, it is more preferable to adjust the overall retardation as a combination. When the first and second optically anisotropic layers are combined, it is preferable that Re as a whole is 30 to 200 nm and Rth is 60 to 500 nm.

  In the present invention, the first optically anisotropic layer aligns rod-like smectic A liquid crystal molecules by applying a composition containing a rod-like smectic A liquid crystal compound on the alignment film containing the polymer for the alignment film. It is an optically anisotropic layer formed. As shown in FIG. 4, it can be incorporated into the liquid crystal display device as an integrated polarizing plate having a retardation film of the present invention including a support and an alignment film and a polarizing film, or incorporated in the form of a retardation film. You can also. Alternatively, after forming the first optically anisotropic layer on the temporary support, only the optically anisotropic layer or the optically anisotropic layer may be transferred together with the alignment film and incorporated in the liquid crystal display device. In the scholarly anisotropic layer of the present invention, the rod-like smectic A liquid crystal molecules are preferably aligned horizontally. Preferred rod-like smectic A liquid crystal compounds are as described above. In the case of a rod-like smectic A liquid crystal compound having a polymerizable group, it is preferably fixed in a substantially horizontal (homogeneous) orientation. Substantially horizontal means that the average angle (average inclination angle) between the major axis direction of the rod-like smectic A liquid crystal compound and the surface of the optically anisotropic layer is in the range of 0 ° to 10 °. The rod-like smectic A liquid crystal compound may be obliquely aligned. In the case of oblique orientation, the average inclination angle is preferably 0 ° to 20 °.

  On the other hand, as for the second optically anisotropic layer, as described above, the material and the number of constituent layers are not particularly limited. According to the optically anisotropic layer exhibiting optical anisotropy expressed by the orientation of the molecules of the liquid crystalline compound, it is possible to realize optical properties that cannot be obtained with a conventional stretched birefringent polymer film. In particular, a first optical anisotropy layer exhibiting optical anisotropy expressed by the molecular orientation of the rod-like smectic A liquid crystalline compound, and a second optical exhibiting optical anisotropy expressed by the molecular orientation of the discotic compound. By combining with the anisotropic layer, the optical characteristics of the liquid crystal display device can be remarkably improved.

  In the present invention, it is preferable to use a discotic liquid crystalline compound or a polymer film for forming the second optically anisotropic layer. The discotic liquid crystalline compound is preferably aligned substantially horizontally (average tilt angle in the range of 0 to 10 degrees) with respect to the layer plane. Discotic liquid crystalline compounds are disclosed in various documents (C. Destrade et al., Mol. Crysr. Liq. Cryst., Vol. 71, page 111 (1981); edited by The Chemical Society of Japan, Quarterly Chemical Review, No. 22, Liquid Crystal Chemistry, Chapter 5, Chapter 10 Section 2 (1994); B. Kohne et al., Angew. Chem. Soc. Chem. Comm., Page 1794 (1985); J. Zhang et al., J Am.Chem.Soc., Vol.116, page 2655 (1994)). The polymerization of discotic liquid crystalline compounds is described in JP-A-8-27284.

The discotic liquid crystalline compound preferably has a polymerizable group so that it can be fixed by polymerization. For example, a structure in which a polymerizable group is bonded as a substituent to a discotic core of a discotic liquid crystalline compound can be considered. However, when a polymerizable group is directly connected to the discotic core, the alignment state is maintained in the polymerization reaction. It becomes difficult. Therefore, a structure having a linking group between the discotic core and the polymerizable group is preferable. That is, the discotic liquid crystalline compound having a polymerizable group is preferably a compound represented by the following general formula (VI).
Formula (VI) D (-LP) _n
In the formula, D is a discotic core, L is a divalent linking group, P is a polymerizable group, and n is an integer of 4 to 12.

  Preferred specific examples of the discotic core (D), the divalent linking group (L), and the polymerizable group (P) in the formula (III) are (D1) described in JP-A-2001-4837, respectively. To (D15), (L1) to (L25), and (P1) to (P18), and the contents described in the publication can be preferably used.

Also in the case of a discotic liquid crystalline compound having a polymerizable group, it is preferable to substantially align horizontally. Substantially horizontal means that the average angle (average inclination angle) between the disc surface of the discotic liquid crystal compound molecule and the surface of the optically anisotropic layer is in the range of 0 ° to 10 °.
The discotic liquid crystalline compound may be obliquely aligned. In the case of oblique orientation, the average inclination angle is preferably 0 ° to 20 °.

  The high molecular polymer preferably used for the second optically anisotropic layer may be any polymer having an optically negative refractive index anisotropy, but Re is 0 to 10 nm with respect to visible light. From the viewpoint, polyolefins such as cellulose triacetate, ZEONEX, ZEONOR (both manufactured by Nippon Zeon Co., Ltd.), and ARTON (manufactured by JSR Co., Ltd.) are preferably used. Other examples include non-birefringent optical resin materials as described in JP-A-8-110402 or JP-A-11-293116.

In the present invention, a horizontal alignment agent can be used. The horizontal alignment agent suitably used in the present invention is a triazine compound represented by the following general formula (VI).

In general formula (VI), the substituent represented by R is a substituted or unsubstituted linear or branched alkyl group having 3 to 50 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 50 carbon atoms. Represents. The substituent represented by R is preferably a substituted phenyl group having 10 to 30 carbon atoms, and it is preferable that at least one fluorine atom is substituted as the substituent.
Specific compounds represented by the general formula (VI) are shown below, but the present invention is not limited thereto.

Hereinafter, the invention will be described in more detail with reference to examples of the retardation plate, the polarizing plate, and the liquid crystal display device using them. The materials, reagents, ratios, operations and the like shown in the following examples can be appropriately changed without departing from the spirit of the present invention. Therefore, the scope of the present invention is not limited to the specific examples shown below.
[Example 1]
1. Production of Optically Anisotropic Layer (1) Formation of Alignment Film Layer An optically isotropic triacetylcellulose film having a thickness of 100 μm, a width of 150 mm, and a length of 200 m was used as a transparent support. The alignment film polymer (AL-1) of the present invention is dissolved in a water / methanol mixture, diluted to 4% by mass, triethylamine is added as a neutralizing agent, and a coating liquid for forming an alignment film is prepared. Liquid. This coating solution was continuously applied to one side of the transparent support, and the coating layer was heated at 120 ° C. for 2 minutes and dried to form a film having a thickness of 1 μm. Subsequently, the rubbing process was continuously implemented in the longitudinal direction (conveyance direction) of the transparent support to form an alignment film E-101.

(2) Formation of liquid crystalline compound layer A coating liquid having the following composition was continuously applied onto the alignment film subjected to the rubbing treatment using a bar coater. The coating layer was heated at 100 ° C. for 1 minute to align rod-like smectic A liquid crystal molecules. The rod-shaped smectic A liquid crystal molecules were polymerized by irradiating with 600 mJ / cm ² ultraviolet rays at that temperature for 4 seconds to fix the alignment state. Thus, an optically anisotropic layer was formed, and an optically anisotropic layer R-101 was produced. This optically anisotropic layer had a slow axis in a direction orthogonal to the longitudinal direction (rubbing direction) of the transparent support, and the Re value at 550 nm measured by the above method was 72 nm. Further, it had an optically positive refractive index anisotropy, and the Re value in the entire visible light range was 76 ± 8 nm.
────────────────────────────────────
Optically anisotropic layer (A) coating solution composition ─────────────────────────────────────
The following rod-like smectic A liquid crystal molecules V-1 38.5 mass ratio The following sensitizer 0.35 mass ratio The following photopolymerization initiator 1.15 mass ratio The following alignment controller D-1 0.20 mass ratio Methyl ethyl ketone 59.8 mass ratio ────────────────────────────────────

(3) Evaluation of orientation defect of optically anisotropic layer The produced optically anisotropic layer was observed under a polarizing microscope, and the orientation defect was evaluated. As a result of evaluating the number of point defects (average value in the 1.0 mm ² range), the number of alignment defects was 10 or less in the 1.0 mm ² range.

(4) Evaluation of adhesion After preparing the optically anisotropic layer, the surface was scratched with a metal fitting, and the ease of peeling of the optically anisotropic layer from the transparent support was evaluated. As an evaluation standard, the optically anisotropic layer R-101 was at the A level as a result of evaluation in three stages: A: not peeled off at all, B: peeled off a little, and C: easy to peel off.

2. Production of Polarizing Plate A roll-shaped polyvinyl alcohol film having a thickness of 80 μm was continuously stretched 5 times in an iodine aqueous solution and dried to obtain a polarizing film. A roll-shaped optically anisotropic layer (R-101) having a saponified roll-shaped cellulose triacetate film (Fujitac TD80UF, manufactured by Fuji Photo Film Co., Ltd.) on one surface of the polarizing film and a saponified surface on the other surface. The transparent support of () was continuously bonded to produce polarizing plate H-101.

3. Production of Liquid Crystal Display Device A liquid crystal display device having the structure shown in FIG. 4 was produced. That is, the upper polarizing plate 08 having the first optical anisotropic layer 03, the liquid crystal cell 16, and the lower polarizing plate 15 having the second optical anisotropic layer 13 are stacked from the observation direction (upper layer), and the back A light source (not shown) was placed. As the upper polarizing plate 08 having the first optically anisotropic layer 03, the polarizing plate H-101 having the optically anisotropic layer R-101 formed using the alignment film of the present invention prepared above was used. . Hereinafter, the production of the lower polarizing plate having the liquid crystal cell and the second optically anisotropic layer as other members will be described.

(1) Production of Liquid Crystal Cell A VA mode liquid crystal cell was produced by the following procedure. After applying an alignment film (for example, JALS204R manufactured by JSR Corporation) to the substrate surface, the tilt angle with respect to the so-called substrate surface, which is a director indicating the alignment direction of liquid crystalline molecules, was set to about 89 ° by rubbing treatment. The cell gap between the upper and lower substrates is 3.5 μm, and a liquid crystal (MLC-6608 made by Merck) with a negative dielectric anisotropy and Δn = 0.0813 and Δε = −4.6 is dropped between them. And enclosed.

(2) Production of second optically anisotropic layer (production of alignment film layer)
On the Fujitac TD80UF (Re = 3 nm, Rth = 50 nm) subjected to saponification treatment in the same manner as the transparent support, a coating solution having the following composition was applied at 28 ml / m ² with a # 16 wire bar coater.
Alignment film coating solution composition Modified polyvinyl alcohol 20 parts by weight Water 361 parts by weight Methanol 119 parts by weight Glutaraldehyde (crosslinking agent) 0.5 parts by weight

  Drying was performed at 25 ° C. for 60 seconds, 60 ° C. warm air for 60 seconds, and 90 ° C. warm air for 150 seconds. The alignment film thickness after drying was 1.1 μm. The alignment film was rubbed in the same direction as the slow axis of Fujitac TD-80UF.

(Formation of second optically anisotropic layer)
A coating liquid containing a discotic liquid crystal having the following composition was applied on the alignment film subjected to the rubbing treatment.
Composition of coating liquid for discotic liquid crystal layer 32.6% by mass of the following discotic liquid crystal compound
Following orientation control agent D-2 0.4 mass%
Ethylene oxide modified trimethylolpropane triacrylate (V # 360, manufactured by Osaka Organic Chemical Co., Ltd.) 3.5% by mass
Sensitizer (Kayacure DETX, manufactured by Nippon Kayaku Co., Ltd.) 0.4% by mass
Photopolymerization initiator (Irgacure 907, manufactured by Ciba Geigy) 1.1% by mass
Methyl ethyl ketone 62.0% by mass

  Then, it dried by heating for 2 minutes in a 130 degreeC drying zone, and orientated the discotic compound. Next, using a 120 W / cm high pressure mercury lamp at 130 ° C., UV irradiation was performed for 4 seconds to polymerize the discotic compound. Then, it was allowed to cool to room temperature, a thickness of 1.4 μm, an optically negative refractive index anisotropy, a second optical anisotropy with Re of 0 nm and Rth of 138 nm measured by the above method. The conductive layer R-201 was formed. The discotic liquid crystalline compound of the second optically anisotropic layer was horizontally aligned within a range of ± 2 °.

(Preparation of polarizing plate)
The produced second optically anisotropic layer R-201 and Fujitac TD80UF were attached to both surfaces of the polarizing film using a polyvinyl alcohol-based adhesive to produce an integrated polarizing plate H-201.

(3) Production of Liquid Crystal Display Device A polarizing plate H-101 having an optically anisotropic layer R-101 produced using the alignment film of the present invention is so arranged that the optically anisotropic layer is in contact with the lower liquid crystal cell substrate. Incorporated into the liquid crystal display device. In addition, the polarizing plate H-201 having the second optically anisotropic layer R-201 produced as described above is arranged so that the second optically anisotropic layer is in contact with the upper liquid crystal cell substrate. Incorporated. Thus, the liquid crystal display device U-101 of the present invention was produced.

(4) Measurement of leakage light of liquid crystal display device produced and evaluation of color unevenness The viewing angle dependence of the transmittance of the liquid crystal display device U-101 produced in this way was measured. The elevation angle was measured from the front in an oblique direction up to 80 ° every 10 °, and the azimuth was measured up to 360 ° every 10 ° on the basis of the horizontal right direction (0 °). It has been found that the luminance at the time of black display increases as the elevation angle increases from the front direction, and the leakage light transmittance also increases and takes a maximum value near the elevation angle of 60 °. It was also found that the contrast, which is the ratio between the white display transmittance and the black display transmittance, deteriorates as the black display transmittance increases. Therefore, it was decided to evaluate the viewing angle characteristics based on the maximum values of the black display transmittance at the front and the leakage light transmittance at an elevation angle of 60 °.
In this example, the front contrast ratio was 1000: 1, and the contrast ratio at an elevation angle of 60 ° was 400: 1. Further, the color unevenness of the liquid crystal display device was visually evaluated, but it was very good with no unevenness.

[Comparative Example 1]
In the production method of the optically anisotropic layer shown in Example 1, all the same procedures as in Example 1 were conducted except that the following nematic liquid crystalline compound N-1 was used instead of the rod-like smectic A liquid crystalline compound. An optically anisotropic layer R-102 was produced.

Further, the orientation of the rod-like nematic liquid crystalline molecules of the optically anisotropic layer R-102 has a slow axis in the direction perpendicular to the longitudinal direction (rubbing direction) of the transparent support, as in RL-101. The Re value at 550 nm measured by the above method was 62 nm. Similarly, the evaluation results of alignment defects and adhesion of these optical anisotropic layers were 10 or less in the 1.0 mm ² range.

  Next, using this optically anisotropic layer R-102, polarizing plates H-102 to 108 were produced in the same manner as in Example 1. Further, a liquid crystal display device U- in which the same VA mode liquid crystal cell as that produced in Example 1 is sandwiched between each of these polarizing plates and the same polarizing plate as the polarizing plate H-201 produced in Example 1. As a result of measuring leakage light in the same manner as in Example 1, the front contrast ratio was 500: 1, and the contrast ratio at an elevation angle of 60 ° was 200: 1. Further, the color unevenness of the liquid crystal display device was visually evaluated, but it was very good with no unevenness.

  As can be seen from the above results, the optical anisotropy in which the major axis direction and the rubbing direction of the rod-like smectic A liquid crystalline molecules are aligned substantially orthogonally without unevenness by using a specific alignment film in the examples of the present invention. In addition, liquid crystal display devices using these optically anisotropic layers can also provide good image display performance as a result of less leakage light, high contrast, and no unevenness. It was. Even when an optically anisotropic layer is produced using a rod-like nematic liquid crystal compound instead of a rod-like smectic A liquid crystal compound, the leakage light of the liquid crystal display device can be reduced, and a high contrast non-uniform image can be obtained. However, when an optically anisotropic layer formed using a rod-like smectic A liquid crystalline compound was used, an image with higher contrast and no unevenness was obtained.

It is the top view which showed typically a mode that rod-shaped smectic A liquid crystal molecule was orientating. It is (a) side view and (b) top view which show typically one embodiment of the phase contrast plate of the present invention. It is the (a) side view and (b) top view which show typically one Embodiment of the elliptically polarizing plate of this invention. It is a schematic sectional drawing which shows the structure of one Embodiment of the liquid crystal display device of this invention.

Explanation of symbols

01 transparent support 02 alignment film 03 optically anisotropic layer (first optically anisotropic layer in FIG. 4)
04 Rod Smectic A Liquid Crystal Molecule 05 Retardation Plate of the Present Invention 06 Transparent Protective Film 07 Linear Polarizing Film 08 Upper Polarizing Film 09 Transparent Protective Film 10 Linear Polarizing Film 11 Transparent Support 12 Orientation Film 13 Second Optical Anisotropic Layer 14 Phase difference plate of the present invention 15 Lower polarizing plate 16 Liquid crystal cell 17 Liquid crystal display device

Claims (15)

An alignment film containing a polymer having at least one structural unit represented by the following general formula (A) on the support, and smectic A controlled in alignment by the alignment film and fixed in the alignment state A retardation plate having an optically anisotropic layer containing a rod-like liquid crystal compound exhibiting a liquid crystal phase (hereinafter referred to as “rod-like smectic A liquid crystal compound”).

(In the formula, Mp represents a (2 + n) -valent linking group bonded to L at n sites, L represents a (1 + n) -valent linking group, n represents 1 or 2, and X represents hydrogen. Represents a bonding group, provided that the formula weight of the structural unit represented by formula (A) is 110 or more.) The phase difference plate according to claim 1, wherein the structural unit represented by the general formula (A) is represented by any one of the following general formula (I), general formula (II), and general formula (III).

(In the formula, R ¹ represents a hydrogen atom, a methyl group, a halogen atom or a cyano group, P ¹ represents an oxygen atom, —CO— or —NR ¹² —, and R ¹² represents a hydrogen atom and has 1 to 6 carbon atoms. Represents a substituted or unsubstituted alkyl group or a substituted or unsubstituted aryl group having 6 or more carbon atoms, and L ¹ represents a substituted or unsubstituted alkylene group, divalent cycloaliphatic group, divalent aromatic A divalent linking group selected from the group consisting of a group, a divalent heterocyclic group and a combination thereof, X ¹ represents a hydrogen bonding group, and n1 represents an integer of 1 or more.)

(In the formula, R ² represents a hydrogen atom, a methyl group, a halogen atom or a cyano group, L ²¹ represents a substituted or unsubstituted divalent aromatic group or divalent heterocyclic group, and P ²¹ represents a single atom. Represents a divalent linking group selected from the group consisting of a bond, —O—, —NR ²¹ —, —CO—, —S—, —SO—, —SO ₂ — and combinations thereof, and R ²¹ represents a hydrogen atom. Or a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, wherein L ²² is a substituted or unsubstituted alkylene group, divalent cycloaliphatic group, divalent aromatic group, divalent heterocycle. And a divalent linking group selected from the group consisting of a group and a combination thereof, X ² represents a hydrogen bonding group, and n2 is an integer of 0 or more.)

(Wherein L ³¹ represents a substituted or unsubstituted divalent aromatic group or divalent heterocyclic group, and P ³¹ represents a single bond, —O—, —NR ³¹ —, —CO—, —S Represents a divalent linking group selected from the group consisting of —, —SO—, —SO ₂ — and combinations thereof, and R ³¹ represents a hydrogen atom or a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms. , L ³² represents a divalent linking group selected from the group consisting of a substituted or unsubstituted alkylene group, divalent cycloaliphatic group, divalent aromatic group, divalent heterocyclic group, and combinations thereof. X ³ represents a hydrogen bonding group, and n3 is an integer of 0 or more.) The structural unit represented by the general formula (A) is represented by the general formula (I), in which R ¹ represents a hydrogen atom or a methyl group, P ¹ represents —NR ¹² —, R ¹² Represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms substituted by a hydrogen bonding group, and L ¹ is a substituted or unsubstituted divalent aromatic group, divalent heterocyclic group, and combinations thereof The retardation plate according to claim 2, which represents a divalent linking group selected from the group consisting of: X ¹ represents a hydrogen bonding group, and n 1 is an integer of 1 to 4. The structural unit represented by the general formula (A) is represented by the general formula (I), in which R ¹ represents a hydrogen atom or a methyl group, P ¹ represents —NH—, and L ¹ represents A divalent linking group selected from the group consisting of a substituted or unsubstituted divalent aromatic group and a combination thereof, X ¹ represents a hydrogen bonding group, and n1 is an integer of 1 to 3. The phase difference plate according to 2. The structural unit represented by the general formula (A) is represented by the general formula (II), in which R ² represents a hydrogen atom or a methyl group, and L ²¹ represents a substituted or unsubstituted divalent divalent group. Represents an aromatic group or a divalent heterocyclic group, and P ²¹ represents a divalent linking group selected from the group consisting of —O—, —NR ²¹ —, —CO—, —SO ₂ — and combinations thereof. R ²¹ represents a hydrogen atom or a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, and L ²² represents a substituted or unsubstituted divalent aromatic group, divalent heterocyclic group, and combinations thereof. The retardation plate according to claim 2, wherein the retardation plate represents a divalent linking group selected from the group consisting of: X ² represents a hydrogen bonding group, and n2 is an integer of 0 to 3. The structural unit represented by the general formula (A) is represented by the general formula (III), and L ³¹ is a substituted or unsubstituted divalent aromatic group or divalent heterocyclic group. represents, P ³¹ is ^{-O -, - NR 31 -,} - CO -, - SO 2 - and represents a divalent linking group selected from the group consisting of, R ³¹ is a hydrogen atom or a carbon atoms 1 represents a substituted or unsubstituted alkyl group of 1 to 6, and L ³² represents a substituted or unsubstituted divalent aromatic group, a divalent heterocyclic group, and a divalent linkage selected from the combination thereof The retardation plate according to claim 2, wherein X ³ represents a hydrogen bonding group, and n 3 is an integer of 0 to 3. X, X ¹ , X ² and X ³ are each a hydrogen bonding group selected from —CO ₂ H, —SO ₂ NH ₂ and —CONH _2. The retardation plate described. The phase difference plate according to claim 1, wherein the molecules of the rod-like smectic A liquid crystalline compound have their major axes aligned substantially perpendicular to the rubbing direction of the alignment film. The support has a longitudinal direction, the rubbing direction of the alignment film is substantially parallel to the longitudinal direction of the support, and the molecules of the rod-like smectic A liquid crystalline compound have its long axis. The phase difference plate according to claim 1, wherein the phase difference plate is oriented so as to be substantially orthogonal to the longitudinal direction. A composition containing a polymer containing a structural unit represented by the general formula (A) in claim 1 is applied to the surface of a support having a longitudinal direction to form a layer, and the surface of the layer is Rubbing substantially parallel to the longitudinal direction to form an alignment film; and applying a composition containing a rod-like smectic A liquid crystal compound to the rubbing-treated surface of the alignment film to produce the rod-like smectic A liquid crystal And a step of forming an optically anisotropic layer by orienting the molecules of the active compound so that the major axis thereof is substantially orthogonal to the rubbing direction and fixing in the aligned state. . The polarizing plate which has the phase difference plate of any one of the said Claims 1-9, and a polarizing film. The polarizing plate according to claim 11, wherein the slow axis of the optically anisotropic layer and the absorption axis of the polarizing film are substantially perpendicular to each other. Two polarizing films having mutually perpendicular absorption axes, a liquid crystal layer composed of a pair of substrates and a liquid crystalline molecule sandwiched between the two polarizing films, and an external electric field In a non-driving state in which no liquid crystal is applied, the liquid crystal molecules are aligned in a direction substantially perpendicular to the substrate, have an optically positive refractive index anisotropy, and Re is 40 to At least one first optically anisotropic layer having a thickness of 150 nm, a second optically anisotropic material having optically negative refractive index anisotropy, Re of 0 to 10 nm, and Rth of 60 to 250 nm A liquid crystal display device having at least one layer of an organic layer, wherein the first optical anisotropic layer is the optical anisotropic layer according to claim 1. The rod-shaped smectic A liquid crystalline compound in the first optically anisotropic layer is horizontally aligned with its major axis substantially perpendicular to one of the absorption axes of the two polarizing films. 14. A liquid crystal display device according to item 13. 15. The liquid crystal display device according to claim 13, wherein the second optically anisotropic layer is a layer formed of discotic liquid crystal molecules that are substantially horizontally aligned.

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