JP2005122156A - Optical retardation plate and image display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical retardation plate in which molecules of a discotic liquid crystal compound are aligned without unevenness so that disk faces of molecules are roughly vertical to the flat face of an alignment layer and the faces of the molecules and the rubbing direction are roughly orthogonal even when an existing aligment layer is used. <P>SOLUTION: The optical retardation plate has at least a layer of an optical anisotropic layer on a transparent supporting body and it is characterized by being an optical retardation plate in which the optical anisotropic layer is formed using the liquid crystal compound expressed by, for example, a general formula. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a retardation plate using a novel discotic liquid crystalline compound. In particular, the present invention relates to a phase difference plate in which a disc surface of a liquid crystalline compound and a transparent support plane are substantially perpendicular and the disc surface and the rubbing direction are oriented substantially orthogonally. Furthermore, the present invention relates to an image display device using the retardation plate.

  A liquid crystal display device usually comprises a liquid crystal cell, a polarizing element, and a retardation plate. In a transmissive liquid crystal display device, usually, two polarizing elements are arranged on both sides of a liquid crystal cell, and one or two retardation plates are arranged between the liquid crystal cell and the polarizing element. In a reflection type liquid crystal display device, usually, a reflection plate, a liquid crystal cell, a single phase difference plate, and a single polarizing element are arranged in this order. A liquid crystal cell usually consists of a rod-like liquid crystalline molecular layer, two substrates for encapsulating it, an electrode layer for applying voltage to the rod-like liquid crystalline molecules, and an alignment film layer for controlling the orientation of the rod-like liquid crystalline molecules. Become. 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-G).

  The phase difference plate is used in various liquid crystal display devices in order to eliminate image coloring and expand the viewing angle. As the retardation film, a stretched birefringent polymer film has been conventionally used. It has been proposed to use a retardation plate having an optically anisotropic layer formed of liquid crystalline molecules on a transparent support, instead of the retardation plate 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 molecules.

  The optical properties of the retardation plate are determined according to the optical properties of the liquid crystal cell, specifically, the display mode differences as described above. When liquid crystalline molecules are used, retardation plates 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 a phase difference plate using liquid crystal molecules, ones corresponding to various display modes have already been proposed. For example, a retardation plate for a TN mode liquid crystal cell is described in each specification of Patent Documents 1 to 4. Patent Documents 5 and 6 describe liquid crystal cell retardation plates in IPS mode or FLC mode. Furthermore, OCB mode or HAN mode liquid crystal cell retardation plates are described in Patent Documents 7 and 8. Furthermore, a retardation plate for an STN mode liquid crystal cell is described in Patent Document 9. A retardation plate for a VA mode liquid crystal cell is described in Patent Document 10.

  In order to cope with these various display modes, an alignment film that controls the respective molecules of the discotic liquid crystal compound and the rod-like liquid crystal compound to a desired alignment angle is essential. Some techniques cannot be fully oriented. For example, for the IPS mode described in Patent Documents 5 and 6, a phase difference plate in which molecules of a discotic liquid crystalline compound are aligned substantially perpendicular to the plane of the alignment film can be suitably used. Has been described. As an alignment film that can align a discotic liquid crystalline compound in such an alignment state, for example, Patent Document 11 proposes an alignment film into which a hydrophobic substituent is introduced. However, when these alignment films are used, the molecules 01 of the discotic liquid crystal compound are actually aligned with the disc surface and the rubbing direction 04 in parallel as shown in FIG. Although it can be aligned perpendicular to the plane 02, as shown in FIG. 1B, the discotic liquid crystal compound molecule 01 is aligned with its disc surface and the rubbing direction 04 orthogonal, and the alignment film It was difficult to align the surface of the plane 02 vertically with no unevenness.

In the case of a rod-like liquid crystal compound, as a method for aligning the rod-like liquid crystal compound 03 as shown in FIG. 2 so that its long axis is substantially orthogonal to the rubbing direction 04, for example, Patent Documents 12 to 17 are used. As described in the above, a method using an alignment film in which a carbazole ring, a fluorene ring, or the like is substituted with a polymer main chain is known. However, as described later in Examples, these alignment films and conventional discotics are used. In the case of a liquid crystal compound, it is difficult to align the disk surface and the rubbing direction 04 perpendicular to each other and to be perpendicular to the alignment film plane 02 without unevenness.
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 Publication No. 96/37804 Pamphlet JP-A-9-26572 Japanese Patent No. 2866372 JP 2000-282041 A JP 2002-62427 A JP 2002-90545 A JP 2002-98836 A JP 2002-268068 A JP 2002-309010 A JP 2002-350859 A

  The problem to be solved by the present invention is that, even if an existing alignment film is used, the disc surface of the discotic liquid crystal compound is substantially perpendicular to the plane of the alignment film, and the disc surface of the discotic liquid crystal compound and the rubbing direction Is to provide a phase difference plate that is oriented substantially orthogonally and without unevenness. It is another object of the present invention to provide an image display device with improved image display characteristics, particularly an IPS mode image display device.

The above problem is solved by the following means.
(1) A retardation plate having at least one optically anisotropic layer on a transparent support, wherein the optically anisotropic layer is formed using a liquid crystalline compound represented by the following general formula (I) A retardation film characterized by being made.
Formula (I)

In the general formula _{(I), Y 11, Y} 12, Y 13, Y 21, Y 22, Y 23, Y 24, Y 25, Y 26 represents a methine group or a nitrogen atom independently. X ₁ , X ₂ and X ₃ each independently represent an oxygen atom, a sulfur atom, methylene or imino. L ₁ , L ₂ and L ₃ each independently represents a single bond or a divalent linking group. R ₁ , R ₂ and R ₃ are each independently an alkyl group, alkenyl group, alkynyl group, aryl group, substituted or unsubstituted amino group, alkoxy group, aryloxy group, acyl group, alkoxycarbonyl group, aryloxycarbonyl Group, acyloxy group, acylamino group, alkoxycarbonylamino group, aryloxycarbonylamino group, alkylsulfonylamino group, arylsulfonylamino group, sulfamoyl group, carbamoyl group, alkylthio group, arylthio group, alkylsulfonyl group, arylsulfonyl group, alkyl Sulfinyl group, arylsulfinyl group, ureido group, phosphoric acid amide group, hydroxy group, mercapto group, halogen atom, cyano group, sulfo group, carboxyl group, nitro group, hydroxamic acid group, sulfino group Hydrazino group, an imino group, a heterocyclic group or a silyl group.
(2) The retardation plate according to (1), wherein the optically anisotropic layer is formed using a liquid crystalline compound represented by the following general formula (II).
Formula (II)

In the general formula _{(II), Y 11, Y} 12, Y 13, Y 21, Y 22, Y 23, Y 24, Y 25, Y 26 represents a methine group or a nitrogen atom independently. X ₁ , X ₂ and X ₃ each independently represent an oxygen atom, a sulfur atom, methylene or imino. L ₁ , L ₂ and L ₃ each independently represents a single bond or a divalent linking group. R ₁ , R ₂ and R ₃ each independently represents the following general formula (V).
General formula (V)

In general formula (V), * represents the position bonded to the 5-membered ring in general formula (II). R ₄ is independently a halogen atom, an alkyl group having 1 to 8 carbon atoms, an alkyloxy group having 1 to 8 carbon atoms, an acyl group having 2 to 8 carbon atoms, an acyloxy group having 2 to 8 carbon atoms, An alkoxycarbonyl group having 2 to 8 carbon atoms, a nitro group, or a cyano group is represented. L ₆ represents ** — O—, ** — CO—O—, ** — O—CO—, ** — O—CO—O—, or ** — CH ₂ —, and ** represents a general formula It represents the position bonded to the benzene ring in (V). R ₅ represents a hydrogen atom, a methyl group, an ethyl group or a propyl group. m represents an integer of 2 to 16. l represents an integer of 0 to 4. R ₆ represents a hydrogen atom or a methyl group.
(3) The retardation film according to (1) or (2), wherein an alignment film layer is provided between the transparent support and at least one optically anisotropic layer.
(4) The liquid crystal compound molecule is oriented and fixed with the angle formed by the disk surface of the molecule and the transparent support surface being substantially perpendicular, and the molecule is fixed. The phase difference plate (5) is characterized in that the molecules of the liquid crystalline compound are aligned and fixed with the angle formed by the disc surface of the molecule and the rubbing direction of the alignment film layer being substantially orthogonal to each other (3) or (4) ).
(6) An image display device comprising a liquid crystal cell and the retardation plate according to any one of (1) to (5).
(7) The image display device according to (6), wherein the liquid crystal cell is in an IPS (In-Plane Switching) mode.

  In the present specification, “substantially perpendicular” and “substantially orthogonal” mean not only an embodiment that is exactly 90 °, but also an embodiment that is 90 ± 5 °.

  According to the present invention, by using a specific liquid crystal compound, the discotic liquid crystal molecules, which have been difficult in the past, are made substantially perpendicular to the plane of the alignment film, and the disc surface of the discotic liquid crystal molecules and the rubbing direction Can be aligned substantially orthogonally and without unevenness. In addition, the retardation plate having an optically anisotropic layer containing a liquid crystalline compound fixed in the alignment state contributes to improvement of display characteristics of the image display device.

Hereinafter, the contents of the present invention will be described in detail.
[Liquid crystal compounds]
The liquid crystalline compound according to the present invention is represented by the following general formula (I).
Formula (I)

In the general formula _{(I), Y 11, Y} 12, Y 13, Y 21, Y 22, Y 23, Y 24, Y 25, Y 26 represents a methine group or a nitrogen atom independently.

When Y ₁₁ , Y ₁₂ , Y ₁₃ , Y ₂₁ , Y ₂₂ , Y ₂₃ , Y ₂₄ , Y ₂₅ , Y ₂₆ are methine, the methine may have a substituent. Examples of the substituent include an alkyl group (eg, methyl group, ethyl group, isopropyl group, tert-butyl group), alkenyl group (eg, vinyl group, allyl group, 2-butenyl group, 3-pentenyl group). ), Alkynyl group (for example, propargyl group, 3-pentynyl group, etc.), aryl group (for example, phenyl group, p-methylphenyl group, naphthyl group, etc.), substituted or unsubstituted amino group (For example, an unsubstituted amino group, a methylamino group, a dimethylamino group, a diethylamino group, an anilino group, etc.), an alkoxy group (for example, a methoxy group, an ethoxy group, a butoxy group, etc.), an aryloxy group ( For example, a phenyloxy group, 2-naphthyloxy group, etc.), an acyl group (for example, acetyl) , Benzoyl group, formyl group, pivaloyl group, etc.), alkoxycarbonyl group (for example, methoxycarbonyl group, ethoxycarbonyl group, etc.), aryloxycarbonyl group (for example, phenyloxycarbonyl group, etc.) An acyloxy group (for example, acetoxy group, benzoyloxy group and the like), an acylamino group (for example, acetylamino group, benzoylamino group and the like), an alkoxycarbonylamino group (for example, methoxycarbonylamino group and the like). ), Aryloxycarbonylamino group (for example, phenyloxycarbonylamino group), alkylsulfonylamino group (for example, methanesulfonylamino group), arylsulfonylamino Group (for example, benzenesulfonylamino group), sulfamoyl group (for example, sulfamoyl group, N-methylsulfamoyl group, N, N-dimethylsulfamoyl group, N-phenylsulfamoyl group) Carbamoyl group (for example, unsubstituted carbamoyl group, N-methylcarbamoyl group, N, N-diethylcarbamoyl group, N-phenylcarbamoyl group, etc.), alkylthio group (for example, methylthio group, ethylthio group) ), Arylthio groups (for example, phenylthio groups and the like), alkylsulfonyl groups (for example, mesyl groups and the like), arylsulfonyl groups (for example, tosyl groups and the like), alkylsulfinyl groups (For example, methanesulfinyl group, etc. Arylsulfinyl group (for example, benzenesulfinyl group), ureido group (for example, unsubstituted ureido group, 3-methylureido group, 3-phenylureido group, etc.), phosphoric acid Amide group (for example, diethyl phosphoric acid amide group, phenylphosphoric acid amide group etc.), hydroxy group, mercapto group, halogen atom (for example, fluorine atom, chlorine atom, bromine atom, iodine atom), cyano group, sulfo group A carboxyl group, a nitro group, a hydroxamic acid group, a sulfino group, a hydrazino group, an imino group, a heterocyclic group (for example, a heterocyclic group having a heteroatom such as a nitrogen atom, an oxygen atom, a sulfur atom, such as an imidazolyl group) , Pyridyl group, quinolyl group, furyl group, piperidyl group, morpholino group, benzoxa Lil group, benzimidazolyl group, etc. benzthiazolyl group), a silyl group (e.g., trimethylsilyl group, etc. triphenylsilyl group) are included. These substituents may be further substituted with these substituents.

  Among these, methine substituents include alkyl groups, alkoxy groups, aryloxy groups, acyl groups, alkoxycarbonyl groups, acyloxy groups, acylamino groups, alkoxycarbonylamino groups, alkylthio groups, arylthio groups, halogen atoms, and cyano. An alkyl group, an alkoxy group, an alkoxycarbonyl group, an acyloxy group, a halogen atom, and a cyano group, more preferably an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, and 2 carbon atoms. Most preferred are an alkoxycarbonyl group having 12 to 12 carbon atoms, an acyloxy group having 2 to 12 carbon atoms, a halogen atom and a cyano group.

In the general formula (I), X ₁ , X ₂ , and X ₃ each independently represent an oxygen atom, a sulfur atom, methylene, or imino. When X ₁ , X ₂ and X ₃ are methylene or imino, they may have a substituent. As the substituent, those mentioned as the substituent for the methine are preferable. These substituents may be further substituted, and the substituents in that case are the same as those mentioned as the substituents that the methine substituent may have.

In general formula (I), L < ₁ >, L < ₂ >, L < ₃ > is a single bond or a bivalent coupling group each independently. When L ₁ , L ₂ and L ₃ are divalent linking groups, each independently represents —O—, —S—, —C (═O) —, —NR ₇ —, —CH═CH—, —C. It is preferably a divalent linking group selected from the group consisting of ≡C—, a divalent cyclic group, and combinations thereof. R ₇ 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 cyclic group represented by L ₁ , L ₂ , and L ₃ is a divalent linking group having at least one cyclic structure. The divalent cyclic group is preferably a 5-membered ring, 6-membered ring, or 7-membered ring, more preferably a 5-membered ring or 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. The cyclic group is preferably an aromatic ring or a heterocyclic ring.

Of the divalent cyclic groups represented by L ₁ , L ₂ and L ₃ , 1,4-phenylene is preferred as the cyclic group having a benzene ring. 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 divalent cyclic group represented by L ₁ , L ₂ and L ₃ may have a substituent. Examples of the substituent include a halogen atom, a cyano group, a nitro group, an alkyl group having 1 to 16 carbon atoms, a halogen-substituted alkyl group having 1 to 16 carbon atoms, and an alkoxy group having 1 to 16 carbon atoms. , An acyl group having 2 to 16 carbon atoms, an alkylthio group having 1 to 16 carbon atoms, an acyloxy group having 2 to 16 carbon atoms, an alkoxycarbonyl group having 2 to 16 carbon atoms, a carbamoyl group, carbon An alkyl-substituted carbamoyl group having 2 to 16 atoms and an acylamino group having 2 to 16 carbon atoms are included.

L ₁ , L ₂ , and L ₃ are each a single bond, * —O—CO—, * —CO—O—, * —CH═CH—, * —C≡C—, * —divalent cyclic group— * -O-CO-divalent cyclic group-, * -CO-O-divalent cyclic group-, * -CH = CH-divalent cyclic group-, * -C≡C-divalent cyclic group Group-, * -divalent cyclic group-O-CO-, * -divalent cyclic group-CO-O-, * -divalent cyclic group-CH = CH-, * -divalent cyclic group- C≡C— is preferred. In particular, a single bond, * —CH═CH—, * —C≡C—, * —CH═CH—divalent cyclic group—, and * —C≡C—divalent cyclic group— are preferable. * Represents a position bonded to a 6-membered ring containing Y ₁₁ , Y ₁₂ and Y ₁₃ in the general formula (I).

In general formula (I), R < ₁ >, R < ₂ >, R < ₃ > is each independently an alkyl group (e.g., methyl group, ethyl group, isopropyl group, tert-butyl group), alkenyl group (e.g., vinyl group, allyl group). , 2-butenyl group, 3-pentenyl group and the like), alkynyl group (for example, propargyl group, 3-pentynyl group and the like), aryl group (for example, phenyl group, p-methylphenyl group, naphthyl group) Substituted, unsubstituted amino group (for example, unsubstituted amino group, methylamino group, dimethylamino group, diethylamino group, anilino group, etc.), alkoxy group (for example, methoxy group, ethoxy group) And butoxy groups), aryloxy groups (for example, phenyloxy groups, 2-naphthyloxy groups, etc.) ), An acyl group (for example, acetyl group, benzoyl group, formyl group, pivaloyl group, etc.), an alkoxycarbonyl group (for example, methoxycarbonyl group, ethoxycarbonyl group, etc.), an aryloxycarbonyl group (for example, , Phenyloxycarbonyl group etc.), acyloxy group (eg acetoxy group, benzoyloxy group etc.), acylamino group (eg acetylamino group, benzoylamino group etc.), alkoxycarbonylamino group ( Examples thereof include a methoxycarbonylamino group), an aryloxycarbonylamino group (for example, a phenyloxycarbonylamino group), an alkylsulfonylamino group (for example, a methanesulfonylamino group). Arylsulfonylamino group (for example, benzenesulfonylamino group), sulfamoyl group (for example, sulfamoyl group, N-methylsulfamoyl group, N, N-dimethylsulfamoyl group, N-phenyl) Sulfamoyl group, etc.), carbamoyl group (eg, unsubstituted carbamoyl group, N-methylcarbamoyl group, N, N-diethylcarbamoyl group, N-phenylcarbamoyl group, etc.), alkylthio group (eg, , Methylthio group, ethylthio group, etc.), arylthio group (eg, phenylthio group etc.), alkylsulfonyl group (eg, mesyl group etc.), arylsulfonyl group (eg, tosyl group etc.) Alkylsulfinyl group) For example, methanesulfinyl group and the like), arylsulfinyl group (for example, benzenesulfinyl group and the like), ureido group (for example, unsubstituted ureido group, 3-methylureido group, 3-phenylureido group and the like) Phosphoric acid amide group (for example, diethylphosphoric acid amide group, phenylphosphoric acid amide group etc.), hydroxy group, mercapto group, halogen atom (for example, fluorine atom, chlorine atom, bromine atom, iodine atom) , Cyano group, sulfo group, carboxyl group, nitro group, hydroxamic acid group, sulfino group, hydrazino group, imino group, heterocyclic group (for example, a heterocyclic group having a hetero atom such as nitrogen atom, oxygen atom, sulfur atom For example, imidazolyl group, pyridyl group, quinolyl group, furyl group, piperi Group, represents a morpholino group, benzoxazolyl group, benzimidazolyl group, etc. benzthiazolyl group), a silyl group (e.g., trimethylsilyl group, etc. triphenylsilyl group). These substituents may be further substituted with these substituents.

R ₁ , R ₂ and R ₃ are more preferably each independently represented by the following general formula (III).

General formula (III) * -L ₁₁ -Q

In the general formula (III), * represents a position bonded to the 5-membered ring in the general formula (I).
Q is each independently a polymerizable group or a methyl group. In the case where the compound represented by the general formula (I) including the retardation plate of the present invention is used for an optical film such as an optical compensation film in which the phase difference does not change due to heat, Q is polymerized. It is preferable that it is a sex group. The polymerization reaction 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.

  Furthermore, the polymerizable group is particularly preferably a functional group capable of addition polymerization reaction. Such a polymerizable group is preferably a polymerizable ethylenically unsaturated group or a ring-opening polymerizable group.

  Examples of the polymerizable ethylenically unsaturated group include the following formulas (M-1) to (M-6).

In formulas (M-3) and (M-4), R represents a hydrogen atom or a substituent. Examples of the substituent include those listed as R ₁ , R ₂ and R ₃ . R is preferably a hydrogen atom or an alkyl group, particularly preferably a hydrogen atom or a methyl group.
Among the above (M-1) to (M-6), (M-1) or (M-2) is preferable, and (M-1) is most preferable.

  The ring-opening polymerizable group is preferably a cyclic ether group, and more preferably an epoxy group or an oxetanyl group, and most preferably an epoxy group.

In the general formula (III), L ₁₁ is a divalent linking group. L ₁₁ is a divalent group selected from the group consisting of —O—, —S—, —C (═O) —, —NR ₇ —, a divalent chain group, a divalent cyclic group, and combinations thereof. A linking group is preferred. R ₇ 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 represented by L ₁₁ means an alkylene group, a substituted alkylene group, an alkenylene group, a substituted alkenylene group, an alkynylene group or a substituted alkynylene group. Of these, an alkylene group, a substituted alkylene group, an alkenylene group, and a substituted alkenylene group are preferable, and an alkylene group and an alkenylene group are more preferable.

The alkylene group as the divalent chain group represented by L ₁₁ may have a branch. The alkylene group preferably has 1 to 16 carbon atoms, more preferably 2 to 14 carbon atoms, and most preferably 2 to 12 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 as the divalent chain group represented by L ₁₁ may have a substituted or unsubstituted alkylene group in the main chain, or may have a branch. The alkenylene group preferably has 2 to 16 carbon atoms, more preferably 2 to 14 carbon atoms, and most preferably 2 to 12 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 as the divalent chain group represented by L ₁₁ may have a substituted or unsubstituted alkylene group in the main chain, and the alkynylene group preferably has 2 to 16 carbon atoms. 2 to 14 is more preferable, and 2 to 12 is most preferable. 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 represented by L ₁₁ include ethylene, trimethylene, tetramethylene, 1-methyl-1,4-butylene, pentamethylene, hexamethylene, octamethylene, nonamethylene, decamethylene and undeca. Examples include methylene, dodecamethylene, 2-butenylene, and 2-butynylene.

The divalent cyclic group represented by L ₁₁ is a divalent linking group having at least one cyclic structure. The divalent cyclic group is preferably a 5-membered ring, 6-membered ring, or 7-membered ring, more preferably a 5-membered ring or 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.

Of the divalent cyclic groups represented by L ₁₁ , 1,4-phenylene is preferable as the cyclic group having a benzene ring. 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 divalent cyclic group represented by L ₁₁ may have a substituent. Examples of the substituent include a halogen atom, a cyano group, a nitro group, an alkyl group having 1 to 16 carbon atoms, a halogen-substituted alkyl group having 1 to 16 carbon atoms, and an alkoxy group having 1 to 16 carbon atoms. , An acyl group having 2 to 16 carbon atoms, an alkylthio group having 1 to 16 carbon atoms, an acyloxy group having 2 to 16 carbon atoms, an alkoxycarbonyl group having 2 to 16 carbon atoms, a carbamoyl group, carbon An alkyl-substituted carbamoyl group having 2 to 16 atoms and an acylamino group having 2 to 16 carbon atoms are included.

R ₁ , R ₂ and R ₃ are more preferably each independently represented by the following general formula (IV).

Formula (IV) * -L ₂₁ -Divalent cyclic group -L ₂₂ -Q ₁

In the general formula (IV), * represents a position bonded to the 5-membered ring in the general formula (I).
Q ₁ is the same as the definition of Q in the general formula (III).
L ₂₁ is a single bond or a divalent linking group. When L ₂₁ is a divalent linking group, it consists of —O—, —S—, —C (═O) —, —NR ₇ —, —CH═CH—, —C≡C—, and combinations thereof. A divalent linking group selected from the group is preferred. R ₇ 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.

L ₂₁ is a single bond, and * —O—CO—, * —CO—O—, * —CH═CH—, * —C≡C— (where * is the * side in the general formula (IV)) Is preferred).

  The divalent cyclic group in general formula (IV) is the same as the definition of the divalent cyclic group in general formula (III).

In the general formula (IV), L ₂₂ is the same as the definition of L _{11 in} the general formula (III).
Examples of the divalent linking group represented by L ₂₂ are shown below. Here, the right side is bonded to the divalent cyclic group in the general formula (IV), and the left side is bonded to Q ₁ .

L-1: -Divalent chain group -O-Divalent cyclic group-
L-2: -Divalent chain group -O-Divalent cyclic group -CO-O-
L-3: -Divalent chain group -O-Divalent cyclic group -O-CO-
L-4: - divalent chain group -O- divalent cyclic group -CO-NR ₇ -
L-5: -Divalent chain group -O-Divalent cyclic group -Divalent chain group-
L-6: -Divalent chain group-O-Divalent cyclic group-Divalent chain group-CO-O-
L-7: -Divalent chain group-O-Divalent cyclic group-Divalent chain group-O-CO-
L-8: -Divalent chain group -O-CO-Divalent cyclic group-
L-9: -Divalent chain group -O-CO-Divalent cyclic group -CO-O-
L-10: -Divalent chain group -O-CO-Divalent cyclic group -O-CO-
L-11: a divalent chain group —O—CO—a divalent cyclic group —CO—NR ₇ —.
L-12: -Divalent chain group-O-CO-Divalent cyclic group-Divalent chain group-
L-13: -Divalent chain group-O-CO-Divalent cyclic group-Divalent chain group-CO-O-
L-14: -Divalent chain group-O-CO-Divalent cyclic group-Divalent chain group-O-CO-
L-15: -Divalent chain group-CO-O-Divalent cyclic group-
L-16: -Divalent chain group -CO-O-Divalent cyclic group -CO-O-
L-17: -Divalent chain group -CO-O-Divalent cyclic group -O-CO-
L-18: - divalent chain group -CO-O- divalent cyclic group -CO-NR ₇ -
L-19: -Divalent chain group-CO-O-Divalent cyclic group-Divalent chain group-
L-20: -Divalent chain group-CO-O-Divalent cyclic group-Divalent chain group-CO-O-
L-21: -Divalent chain group -CO-O-Divalent cyclic group -Divalent chain group -O-CO-
L-22: -Divalent chain group -O-CO-O-Divalent cyclic group-
L-23: -Divalent chain group -O-CO-O-Divalent cyclic group -CO-O-
L-24: -Divalent chain group -O-CO-O-Divalent cyclic group -O-CO-
L-25: - divalent chain group -O-CO-O-divalent cyclic group -CO-NR ₇ -
L-26: -Divalent chain group-O-CO-O-Divalent cyclic group-Divalent chain group-
L-27: -Divalent chain group -O-CO-O-Divalent cyclic group -Divalent chain group -CO-O-
L-28: -Divalent chain group-O-CO-O-Divalent cyclic group-Divalent chain group-O-CO-
L-29: -Divalent chain group-
L-30: -Divalent chain group -O-
L-31: -Divalent chain group -CO-O-
L-32: -Divalent chain group -O-CO-
L-33: - divalent chain group -CO-NR ₇ -
L-34: -Divalent chain group-O-Divalent chain group-
L-35: -Divalent chain group -O-Divalent chain group -O-
L-36: -Divalent chain group -O-Divalent chain group -CO-O-
L-37: -Divalent chain group -O-Divalent chain group -O-CO-

  Among the above, L-2, L-3, L-9, L-10, L-16, L-17, L-23, L-24, L-30, L-31, L-32, L- 35, L-36, and L-37 are preferred.

R ₁ , R ₂ and R ₃ are most preferably each independently represented by the following general formula (V).
General formula (V)

In general formula (V), * represents the position bonded to the 5-membered ring in general formula (I).
R ₄ is independently a halogen atom (preferably a fluorine atom, a chlorine atom, a bromine atom or an iodine atom), an alkyl group having 1 to 8 carbon atoms, an alkyloxy group having 1 to 8 carbon atoms, or 2 to 2 carbon atoms. 8 represents an acyl group, an acyloxy group having 2 to 8 carbon atoms, an alkoxycarbonyl group having 2 to 8 carbon atoms, a nitro group, and a cyano group. Preferably, a halogen atom, an alkyl group having 1 to 3 carbon atoms, an alkyloxy group having 1 to 3 carbon atoms, an acyl group having 2 to 4 carbon atoms, an acyloxy group having 2 to 4 carbon atoms, and the number of carbon atoms 2 to 4 alkoxycarbonyl groups and a cyano group.
l represents an integer of 0 to 4, preferably 0 or 1, and most preferably 0. When l is 2 or more, a plurality of groups represented by R ₄ may be different from each other.
L ₆ represents ** — O—, ** — CO—O—, ** — O—CO—, ** — O—CO—O—, or ** — CH ₂ —, and ** represents a general formula It represents the position bonded to the benzene ring in (V).
R ₅ represents a hydrogen atom, a methyl group, an ethyl group or a propyl group, more preferably a hydrogen atom or a methyl group, and most preferably a hydrogen atom.
m represents an integer of 2 to 16, preferably an integer of 2 to 12. Here, when m is an integer of 5 or more, one —CH— may be replaced by —O—. When m is 8 or more, one or two —CH— may be replaced with —O—. However, when —CH— is replaced with —O—, R ₅ is not linked to —O—.
R ₆ represents a hydrogen atom or a methyl group, preferably a hydrogen atom.

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

  The liquid crystal compound according to the present invention desirably exhibits a liquid crystal phase exhibiting good monodomain properties. When the monodomain property is poor, the resulting structure becomes a polydomain, an orientation defect occurs at the boundary between domains, and light is scattered. If good monodomain properties are exhibited, the retardation plate tends to have a high light transmittance.

The liquid crystal phase liquid crystalline compound according to the present invention is expressed, it can be given a columnar phase and a discotic nematic phase (N _D phase). Of these liquid crystal phases, a discotic nematic phase having a good monodomain property (N _D phase) are most preferred.

  The liquid crystalline compound according to the present invention preferably exhibits a liquid crystal phase in the range of 20 ° C to 300 ° C. More preferably, it is 40 degreeC-280 degreeC, Most preferably, it is 60 degreeC-250 degreeC. Here, the expression of the liquid crystal phase at 20 ° C. to 300 ° C. means that the liquid crystal temperature range crosses 20 ° C. (specifically, for example, 10 ° C. to 22 ° C.) or 300 ° C. (specifically, for example, 298). ° C to 310 ° C). The same applies to 40 ° C to 280 ° C and 60 ° C to 250 ° C.

2. Retardation Plate In one form of the retardation plate of the present invention, an alignment film layer (sometimes referred to simply as “alignment film” in the present specification) on a support, orientation control by the alignment film, and the alignment It has an optically anisotropic layer containing a liquid crystalline compound fixed in a state. FIG. 3 is a schematic sectional view showing an embodiment of the retardation plate of the present invention. A retardation plate 14 shown in FIG. 3 has an alignment film 12 and an optically anisotropic layer 13 on a transparent support 11. The alignment film 12 can be formed on the surface of the transparent support 11 such as a plastic film by coating or vapor deposition. After the surface of the alignment film 12 is rubbed, when a composition (coating liquid) containing a liquid crystal compound is applied to the rubbed surface, the molecules of the liquid crystal compound are aligned by rubbing and aligned at a desired alignment angle. Thereafter, liquid crystal molecules are fixed in the alignment state, the optically anisotropic layer 13 is formed, and the retardation film 14 is obtained.

  In the present invention, it is preferable that the disk surface of the liquid crystal compound molecule and the rubbing direction of the alignment film are substantially orthogonal. Moreover, it is preferable that the angle formed by the disk surface of the molecule and the transparent support plane is substantially vertical.

  4 and 5 are one preferred embodiment of the present invention. Here, FIG. 4 shows a perspective view of an elongated retardation plate, FIG. 5 (a) is a schematic side view (a diagram observed from the a direction in FIG. 4), and FIG. The front schematic diagram (the figure observed from b direction in FIG. 4) is represented. A retardation plate 24 shown in FIG. 5 has an optically anisotropic layer 23 in which an alignment film 22 is provided on a transparent support 21 and the disc surface of the discotic liquid crystalline compound 01 molecule is substantially orthogonal to the rubbing direction 04. The disc surfaces of the molecules of the discotic liquid crystalline compound 01 are aligned substantially perpendicularly to the alignment film plane from the alignment film 22 side to the air interface side. In addition, the transparent support plane and the alignment film plane are substantially parallel. In this specification, “the angle between the disc surface of the molecule and the alignment film plane is substantially perpendicular” and “the disc surface of the molecule and the transparent support plane. Is equivalent to “substantially vertical”.

  For example, if a rubbing process is performed on a long support provided with an alignment film, it is difficult to make the longitudinal direction and the rubbing direction 04 orthogonal. Therefore, in order to produce the retardation plate shown in FIGS. 4 and 5 on a long support provided with an alignment film subjected to rubbing treatment, the disc surface of the molecules of the liquid crystalline compound is the alignment film. The orientation needs to be substantially orthogonal to the rubbing direction.

[Optically anisotropic layer]
The optically anisotropic layer in the present invention includes a state in which the liquid crystalline compound according to the present invention is aligned. Therefore, the optically anisotropic layer exhibits optical anisotropy based on the orientation of the liquid crystalline compound.
The optically anisotropic layer is formed from a composition containing other materials such as a material contributing to controlling the alignment and a material contributing to fixing the alignment state together with the liquid crystalline compound according to the present invention. May be. The liquid crystalline compound according to the present invention can be fixed without impairing the alignment form in the liquid crystal state by once heating to the liquid crystal phase forming temperature and then cooling while maintaining the alignment state. The liquid crystalline compound according to the present invention can also be fixed by heating the composition to which the polymerization initiator has been added to the liquid crystal phase formation temperature, followed by polymerization and cooling. In the present invention, the state in which the alignment state is fixed is a state in which the alignment is maintained in the most typical and preferred embodiment, but is not limited thereto, specifically, usually 0 ° C. to 50 ° C. Under more severe conditions, in a temperature range of −30 ° C. to 70 ° C., the layer has no fluidity, and the fixed alignment form is stable without causing a change in the alignment form by an external field or external force. It means a state where it can continue to be maintained.
Note that when the alignment state is finally fixed, the liquid crystalline composition no longer needs to exhibit liquid crystallinity. For example, when a polymerizable compound is used as the liquid crystal compound, as a result, a polymerization or crosslinking reaction proceeds by a reaction with heat, light, etc., and the liquid crystallinity may be lost by increasing the molecular weight.

[Method of forming optically anisotropic layer]
The optically anisotropic layer is formed by, for example, applying a coating solution prepared by dissolving a liquid crystal compound in a solvent capable of dissolving the liquid crystalline compound on an alignment film formed on a support and provided with orientation, and then 25 It can be formed by drying the solvent used at a temperature of from 130 ° C. to 130 ° C., orienting the liquid crystalline compound, and further fixing it by ultraviolet irradiation or the like, if desired.

  The thickness of the optically anisotropic layer formed in this manner varies depending on the use, for example, depending on the optimum retardation value. It is preferably 10 μm, more preferably 0.5 to 5 μm.

[Additive for optically anisotropic layer]
Additives that can be added to the liquid crystalline compound according to the present invention in forming the optically anisotropic layer include, for example, discotic liquid crystalline molecules described in JP-A-2002-98828 and air described below. Examples include an interfacial alignment controller, an alignment film interfacial alignment controller, a repellency inhibitor, a polymerization initiator, and a polymerizable monomer.

[Air interface alignment control agent]
The liquid crystal compound is aligned at the air interface at the tilt angle of the air interface (the angle formed by the transparent support surface and the disc surface of the liquid crystal compound). Since the tilt angle at the air interface varies depending on the type of liquid crystal compound, it is necessary to arbitrarily control the tilt angle at the air interface.
For controlling the tilt angle, for example, an external field such as an electric field or a magnetic field or an additive can be used, but an additive is preferably used.
Examples of such an additive include a substituted or unsubstituted aliphatic group having 6 to 40 carbon atoms, or a substituted or unsubstituted aliphatic substituted oligosiloxanoxy group having 6 to 40 carbon atoms in the molecule. A compound having at least two is preferred, and a compound having at least two in the molecule is more preferred. For example, a hydrophobic excluded volume effect compound described in JP-A No. 2002-20363 can be used as the air interface alignment control agent.

  The addition amount of the alignment control additive on the air interface side is preferably 0.001% by mass to 20% by mass, more preferably 0.01% by mass to 10% by mass with respect to the liquid crystal compound. A mass% to 5 mass% is most preferred.

[Alignment film interface orientation control agent]
The liquid crystal compound is aligned at the tilt angle of the alignment film interface at the alignment film interface. Since the liquid crystalline compound according to the present invention often exhibits a tilt angle of approximately 90 ° at the alignment film interface, it is not necessary to control the tilt angle. For example, the liquid crystalline compound exhibiting a tilt angle of less than 90 °. When a compound is used or when a tilt angle smaller than 90 ° is required, it is necessary to arbitrarily control the tilt angle at the alignment film interface.
For controlling the tilt angle, for example, an external field such as an electric field or a magnetic field or an additive can be used, but an additive is preferably used.
As such an additive, a compound having a polar group in the molecule is preferable. Examples of the compound having a polar group include a compound having —OH, —NH ₂ , —COOH, —SO ₃ H group or onium salt in the molecule. Specifically, for example, additives described in JP-A No. 2004-101920 can be used.

  The addition amount of the alignment control additive on the alignment film interface side is preferably 0.001% by mass to 10% by mass and more preferably 0.005% by mass to 5% by mass with respect to the liquid crystalline compound according to the present invention. Preferably, 0.01% by mass to 2% by mass is most preferable.

[Anti-repellent agent]
As a material for adding to the liquid crystal compound according to the present invention and preventing repelling at the time of application of the composition, a polymer compound can generally be suitably used. The polymer to be used is not particularly limited as long as it does not significantly inhibit the tilt angle change or orientation of the liquid crystalline compound according to the present invention.
Examples of the polymer are described in JP-A-8-95030, and particularly preferred specific polymer examples include cellulose esters. Examples of cellulose esters include cellulose acetate, cellulose acetate propionate, hydroxypropyl cellulose, and cellulose acetate butyrate. In order not to inhibit the alignment of the liquid crystal compound according to the present invention, the amount of the polymer used for the purpose of preventing repellency is generally in the range of 0.1 to 10% by mass with respect to the discotic compound, More preferably, it is in the range of ˜8 mass%, and further preferably in the range of 0.1 to 5 mass%.

[Polymerization initiator]
In the present invention, the liquid crystalline compound is preferably fixed in a monodomain alignment, that is, in a substantially uniformly aligned state. Therefore, when a polymerizable liquid crystalline compound is used, a liquid crystal is obtained by a polymerization reaction. It is preferable to fix the active compound. The polymerization reaction includes a thermal polymerization reaction using a thermal polymerization initiator, a photopolymerization reaction using a photopolymerization initiator, and a polymerization reaction by electron beam irradiation. In order to prevent the support and the like from being deformed or altered by heat. Also, a photopolymerization reaction and a polymerization reaction by electron beam irradiation are preferable. Examples of the photopolymerization initiator 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-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), a combination of triarylimidazole dimer and p-aminophenyl ketone (US Pat. No. 3,549,367) Description), acridine and phenazine compounds (JP-A-60-105667, U.S. Pat. No. 4,239,850), oxadiazole compounds (U.S. Pat. No. 4,212,970), and the like. The amount of the photopolymerization initiator 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. Light irradiation for the polymerization of the liquid crystalline compound is preferably performed using ultraviolet rays. The irradiation energy is preferably 10mJ~50J / cm ^2, further preferably 50mJ~800mJ / cm ^2. In order to accelerate the photopolymerization reaction, light irradiation may be performed under heating conditions. Further, since the oxygen concentration in the atmosphere is related to the degree of polymerization, when the desired degree of polymerization is not reached in the air, it is preferable to reduce the oxygen concentration by a method such as nitrogen substitution. A preferable oxygen concentration is preferably 10% or less, more preferably 7% or less, and most preferably 3% or less.

[Polymerizable monomer]
As the polymerizable monomer used together with the liquid crystalline compound according to the present invention, the polymerizable monomer has compatibility with the liquid crystalline compound according to the present invention, and unless the liquid crystalline compound according to the present invention significantly causes tilt angle change or alignment inhibition, There is no particular limitation. Among these, compounds having a polymerization active ethylenically unsaturated group such as a vinyl group, a vinyloxy group, an acryloyl group, and a methacryloyl group are preferably used. The addition amount of the polymerizable monomer is generally in the range of 0 to 30% by mass and preferably in the range of 0 to 20% by mass with respect to the liquid crystal compound. In addition, it is particularly preferable to use a monomer having two or more reactive functional groups because an effect of improving the adhesion between the alignment film and the optically anisotropic layer can be expected.

[Application method]
The optically anisotropic layer is formed by preparing a liquid crystal composition coating solution using the following solvent, applying the liquid crystal composition on, for example, an alignment film, and aligning the liquid crystalline compound. The coating liquid can be applied by a known method (for example, a wire bar coating method, an extrusion coating method, a direct gravure coating method, a reverse gravure coating method, or a die coating method).

[Coating solvent]
As the solvent used for preparing the liquid crystal composition, an organic solvent is preferably used. Examples of organic solvents include amides (eg, N, N-dimethylformamide), 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, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone), ethers (eg, tetrahydrofuran, 1,2-dimethoxyethane). Alkyl halides, esters and ketones are preferred. Two or more organic solvents may be used in combination.

  The solid content concentration of the liquid crystal 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 to 40% by mass. % Is 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.

[Alignment film]
Examples of the method for aligning the liquid crystalline compound include a method using an external field such as an electric field and a magnetic field, and a method using an alignment film. In the present invention, it is preferable to use an alignment film.
The alignment film is an organic compound (eg, ω-tricosanoic acid) formed by rubbing treatment of an organic compound (preferably polymer), oblique deposition of an inorganic compound, formation of a layer having a microgroove, or Langmuir-Blodgett method (LB film). , Methyl stearylate). Furthermore, an alignment film in which an alignment function is generated by application of an electric field, application of a magnetic field, or light irradiation is also known.
Any layer can be used as the alignment film as long as the liquid crystal compound of the optically anisotropic layer provided on the alignment film can provide a desired alignment. In the present invention, the alignment film can be rubbed or irradiated with light. The formed alignment film is preferable. In particular, an alignment film formed by a rubbing treatment of a polymer is particularly preferable. The rubbing treatment can be generally carried out by rubbing the surface of the polymer layer several times in a certain direction with paper or cloth. In the present invention, in particular, the method described in the liquid crystal manual (Maruzen Co., Ltd.) is used. Preferably it is done. The thickness of the alignment film is preferably 0.01 to 10 μm, and more preferably 0.05 to 3 μm.
In addition, after aligning the liquid crystalline compound using the alignment film, the liquid crystalline compound is fixed in the aligned state to form an optically anisotropic layer, and only the optically anisotropic layer is polymer film (or transparent support) It may be transferred onto the body). The liquid crystal compound in which the alignment state is fixed can maintain the alignment state without an alignment film. Therefore, in the retardation plate, the alignment film is not essential (although essential in the production of the retardation plate).
In order to align the liquid crystalline compound, a polymer (ordinary alignment polymer) that adjusts the surface energy of the alignment film is used. Specific types of polymers are described in various documents about liquid crystal cells or retardation plates. Any alignment film preferably has a polymerizable group for the purpose of improving the adhesion between the liquid crystal compound and the transparent support. The polymerizable group can be introduced by introducing a repeating unit having a polymerizable group in the side chain or as a substituent of a cyclic group. It is preferable to use an alignment film that forms a chemical bond with the liquid crystalline compound at the interface. Such an alignment film is described in JP-A-9-152509.

  In the present invention, it is preferable to use an alignment film in which the disc surface of the molecules of the liquid crystal compound and the rubbing direction of the alignment film are aligned substantially orthogonally. As such an alignment film, it is preferable to use an alignment film in which the major axis direction of the rod-like liquid crystal compound is aligned substantially perpendicular to the rubbing direction. As such an alignment film, for example, an alignment film in which a polymer main chain is substituted with polystyrene, a carbazole ring, a fluorene ring, or the like described in Patent Documents 12 to 17 can be used.

[Support]
The retardation plate of the present invention has a support. 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. It is preferable to use a polymer film that is transparent and has small optical anisotropy and small wavelength dispersion as the support. Here, when the support is transparent, when the transmittance of the support is measured using a spectrophotometer (UV-2550, manufactured by Shimadzu Corporation), light transmission is performed at a wavelength of 400 nm to 700 nm. It means that the rate is 80% or more.
Specifically, the small chromatic dispersion means that the in-plane retardation ratio (Re400 / Re700) at wavelengths of 400 nm and 700 nm 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 roll-like transparent support is used to laminate the optically anisotropic layer and then cut into a required size. preferable. Examples of the polymer include cellulose ester, polycarbonate, polysulfone, polyethersulfone, polyacrylate and polymethacrylate. Cellulose esters are preferred, acetyl cellulose is more preferred, and triacetyl cellulose is most preferred. The polymer film is preferably formed by a solvent cast method. The thickness of the transparent support is preferably 20 to 500 μm, and more preferably 50 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). 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 an image display device, for example, a liquid crystal display device, a linearly polarizing film, or a transparent protective film.

[Polarizer]
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. Hereinafter, the polarizing film and the transparent protective film will be described.

  Examples of the polarizing film include an iodine polarizing film, a dye polarizing film using a dichroic dye, and a polyene polarizing film. 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 perpendicular to the stretching direction of the film. When the discotic liquid crystalline compound is used for the optically anisotropic layer, the transmission axis of the polarizing film is arranged so as to be substantially parallel to the surface of the discotic liquid crystalline molecule on the alignment film side. . When a rod-like liquid crystalline compound is used, 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 liquid crystalline molecule. Usually, it is preferable to bond to the support side of the retardation plate, but if necessary, it may be bonded to the optically anisotropic layer side.

  A transparent polymer film may be used as a transparent protective film on the optically anisotropic layer side of the retardation plate. 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.

[Liquid Crystal Display]
The retardation plate of the present invention can be used for a liquid crystal display device having liquid crystal cells of various display modes. As described above, the retardation plate of the present invention is useful as an optical compensation sheet for liquid crystal cells. The optical compensation sheet having an optically anisotropic layer made of a liquid crystalline molecule includes TN (Twisted Nematic), IPS (In-Plane Switching), FLC (Ferroelectric Liquid Crystal Bend), OCB (Optically Compensatory Bend) (OCB). Super Twisted Nematic), VA (Vertically Aligned), ECB (Electrically Controlled Birefringence), reflection type is TN, HAN (Hybrid Aligned Nematic), G . The retardation plate and polarizing plate obtained by the present invention can be applied to various liquid crystal display modes depending on the alignment state, but the discotic liquid crystalline compound shown in FIG. 5 is aligned vertically from the alignment film side to the air interface side. The retardation plate having the optically anisotropic layer can be suitably used for a transmissive IPS mode.

  EXAMPLES The present invention will be described below with reference to examples, but the present invention is not limited to these specific examples.

(Example 1) Production of retardation plate [Formation of alignment film]
An optically isotropic triacetyl cellulose 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 following acrylic acid copolymer (PA732) and triethylamine (neutralizing agent) described in JP-A No. 2002-98836 are dissolved in a methanol / water mixed solvent (mass ratio = 30/70) to obtain a 4% by mass solution. Prepared. This solution was continuously applied on the transparent transparent support using a bar coater while being conveyed. The coating layer was heated at 120 ° C. for 5 minutes and dried to form a 1 μm thick layer. While the roll-shaped transparent support provided with the coating layer was transported, the surface of the coating layer was continuously rubbed in the longitudinal direction (transport direction) to form an alignment film.

[Formation of optically anisotropic layer]
A coating solution 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 130 ° C. for 1 minute to align the discotic liquid crystalline molecules. The discotic liquid crystalline molecules were polymerized by irradiating with 600 mJ / cm ² of ultraviolet rays at that temperature, and the alignment state was fixed. Thus, the optically anisotropic layer was formed, and the retardation plate of the present invention was produced. When the in-plane retardation (Re) at a wavelength of 550 nm was measured using KOBRA (manufactured by Oji Scientific Instruments), Re was 100 nm. In addition, when the retardation was measured by changing the observation angle, it was found that the disk surface of the liquid crystalline compound was substantially vertical because the angular dependence of the retardation was almost symmetrical. The angle formed between the disk surface of the molecule and the rubbing direction of the alignment film was 90 °.

────────────────────────────────────
Optically anisotropic layer (A) coating solution composition ─────────────────────────────────────
Liquid crystalline compound (D-8) according to the present invention 100 parts by mass photopolymerization initiator (Irgacure 907, manufactured by Ciba Geigy Japan Ltd.) 2.0 parts by mass The following air interface alignment controller (KK-1) 0.2 parts by mass Part chloroform 270 parts by mass ――――――――――――――――――――――――――――――――――――

(Comparative Example 1)
[Formation of optically anisotropic layer]
On the alignment film produced in Example 1, a coating solution having the following composition was continuously applied using a bar coater. The coating layer was heated at 130 ° C. for 1 minute to align the discotic liquid crystalline molecules. The discotic liquid crystalline molecules were polymerized by irradiating with 600 mJ / cm ² of ultraviolet rays at that temperature, and the alignment state was fixed. Thus, an optically anisotropic layer was formed, and a retardation plate was produced. When the in-plane retardation (Re) at a wavelength of 550 nm was measured using KOBRA (manufactured by Oji Scientific Instruments), Re was 50 nm. In addition, when the retardation was measured by changing the observation angle, it was found that the disk surface of the liquid crystalline compound was not substantially vertical because the angular dependence of retardation did not become symmetrical.
The angle formed between the disk surface of the molecule and the rubbing direction of the alignment film was 90 °.

────────────────────────────────────
Optically anisotropic layer (B) coating composition ────────────────────────────────────
The following conventional liquid crystal compound (JD-1) 100 parts by mass ethylene oxide-modified trimethylolpropane triacrylate (V # 360, manufactured by Osaka Organic Chemical Co., Ltd.) 9.9 parts by mass photopolymerization initiator (Irgacure 907, Ciba Geigy Japan) 3.3 parts by mass sensitizer (Kayacure DETX, manufactured by Nippon Kayaku Co., Ltd.) 1.1 parts by mass The above-mentioned air interface alignment controller (KK-1) 0.2 parts by mass methyl ethyl ketone 270 parts by mass ――――――――――――――――――――――――――――――――――――

[Production of polarizing plate and image display device]
A roll-shaped polyvinyl alcohol film having a thickness of 80 μm was continuously stretched 5 times in an aqueous iodine solution and dried to obtain a polarizing film. Transparency of the roll-shaped retardation plate produced above, in which a saponified roll-shaped cellulose triacetate film (Fujitac TD80UF, manufactured by Fuji Photo Film Co., Ltd.) is saponified on one surface of the polarizing film The support was continuously bonded to produce a polarizing plate. The produced polarizing plate was affixed to the liquid crystal cell for transmission type IPS, and the state which displayed the person image was observed visually, As a result, the image without a nonuniformity was obtained. The results are shown in Table 1.

  From the above results, by using the liquid crystal compound according to the present invention, the liquid crystal molecules, which were difficult with the conventional discotic liquid crystal compounds, are substantially perpendicular, and the surface of the liquid crystal molecules and the rubbing direction are substantially orthogonal. It was found that it was possible to align without unevenness. Moreover, the polarizing plate which gives favorable image display performance as a result was able to be obtained.

(Synthesis Example 1)
D-9 was synthesized according to the following scheme.

5.0 g of (D-3) synthesized according to the method described in the literature (Kim, Bong Gi et al., Molecular Crystals and Liquid Crystals, 2001, 370, 391) was dissolved in 100 ml of CH ₂ Cl _2. 75 ml of boron bromide (1.0 M CH ₂ Cl ₂ solution) was added. After stirring at 40 ° C. for 12 hours, water was added to the reaction solution, and the precipitated crystals were collected by filtration. By drying this crystal, 3.0 g of a trihydroxy compound was obtained.
After dissolving 6.5 g of 4-hydroxybutyl acrylate and 8.0 g of triethylamine in 100 ml of ethyl acetate, a solution in which 4.2 g of methanesulfonyl chloride was dissolved in 50 ml of ethyl acetate was added dropwise at a reaction temperature of 30 ° C. or lower. After stirring for 0.5 hour, 100 ml of water was added to wash the ethyl acetate layer. After liquid separation, the ethyl acetate layer was distilled off, 0.5 g of the above trihydroxy compound, 0.8 g of potassium carbonate and dimethylformamide were added, and the mixture was stirred at 100 ° C. for 5 hours. Water was added to the reaction mixture, and the mixture was extracted with CH ₂ Cl _{2. The} organic layer was concentrated and purified using column chromatography to obtain 0.7 g of D-9 crystals. The ¹ H-NMR spectrum of the obtained D-9 is as follows.

¹ H-NMR (solvent: CDCl ₃ , standard: tetramethylsilane) δ (ppm):
1.70-1.90 (6H, m)
1.90-2.00 (6H, m)
3.95-4.30 (12H, m)
5.80 (3H, d)
6.14 (3H, dd)
6.43 (3H, d)
7.08 (6H, d)
8.13 (6H, d)
9.02 (3H, s)

  The phase transition temperature of D-9 thus obtained was observed by texture observation with a polarizing microscope. As a result, the temperature was increased and the crystal phase was changed to the columnar phase at around 131 ° C., and further from the columnar phase to the discotic nematic around 134 ° C. It changed to a phase, and when it exceeded 138 ° C., it changed to an isotropic liquid phase. That is, it was found that D-9 exhibits a liquid crystal phase between 131 ° C. and 138 ° C., and particularly exhibits a discotic nematic phase between 134 ° C. and 138 ° C.

(Synthesis Example 2)
[Synthesis of D-8]
D-8 was synthesized according to the following scheme.

After dissolving 5 g of 3-bromo-1-propanol in 20 ml of dimethylacetamide, 3.8 ml of acryloyl chloride was added dropwise at a reaction temperature of 40 ° C. or lower. After stirring for 1 hour, 200 ml of water was added and the mixture was extracted with ethyl acetate / hexane. After liquid separation, the organic layer was distilled off, 0.5 g of the trihydroxy compound described in Example 10, 2.0 g of potassium carbonate and dimethylformamide were added, and the mixture was stirred at 100 ° C. for 10 hours.
Water was added to the reaction solution, and the mixture was extracted with CH ₂ Cl _{2. The} organic layer was concentrated and purified using column chromatography to obtain 0.8 g of D-8 crystals. The ¹ H-NMR spectrum of the obtained D-8 is as follows.

¹ H-NMR (solvent: CDCl ₃ , standard: tetramethylsilane) δ (ppm):
2.15-2.30 (6H, m)
4.18 (6H, t)
4.43 (6H, t)
5.86 (3H, d)
6.16 (3H, dd)
6.45 (3H, d)
7.08 (6H, d)
8.16 (6H, d)
9.02 (3H, s)

  The phase transition temperature of the obtained D-8 was measured by texture observation with a polarizing microscope. As a result, the temperature was increased and the crystal phase was changed to a discotic nematic phase around 125 ° C. Transition to phase. That is, it was found that D-8 exhibits a discotic nematic phase between 125 ° C. and 149 ° C.

It is the figure which showed typically the orientation state with respect to the rubbing direction of a discotic liquid crystalline molecule. It is the figure which showed typically the orientation state with respect to the rubbing direction of a rod-shaped liquid crystalline molecule. It is a cross-sectional schematic diagram of one Embodiment of the phase difference plate of this invention. It is a perspective view of one embodiment of a phase difference plate of the present invention. It is (a) side surface schematic diagram and (b) front surface schematic diagram of one Embodiment of the phase difference plate of this invention.

Explanation of symbols

01 discotic liquid crystalline compound 02 alignment film plane 03 rod-shaped liquid crystalline compound 04 rubbing direction 11, 21 transparent support 12, 22 alignment film 13, 23 optically anisotropic layer 14, 24 retardation plate

Claims (7)

A retardation plate having at least one optically anisotropic layer on a transparent support, wherein the optically anisotropic layer is formed using a liquid crystalline compound represented by the following general formula (I) A retardation film characterized by that.
Formula (I)

In the general formula _{(I), Y 11, Y} 12, Y 13, Y 21, Y 22, Y 23, Y 24, Y 25, Y 26 represents a methine group or a nitrogen atom independently. X ₁ , X ₂ and X ₃ each independently represent an oxygen atom, a sulfur atom, methylene or imino. L ₁ , L ₂ and L ₃ each independently represents a single bond or a divalent linking group. R ₁ , R ₂ and R ₃ are each independently an alkyl group, alkenyl group, alkynyl group, aryl group, substituted or unsubstituted amino group, alkoxy group, aryloxy group, acyl group, alkoxycarbonyl group, aryloxycarbonyl Group, acyloxy group, acylamino group, alkoxycarbonylamino group, aryloxycarbonylamino group, alkylsulfonylamino group, arylsulfonylamino group, sulfamoyl group, carbamoyl group, alkylthio group, arylthio group, alkylsulfonyl group, arylsulfonyl group, alkyl Sulfinyl group, arylsulfinyl group, ureido group, phosphoric acid amide group, hydroxy group, mercapto group, halogen atom, cyano group, sulfo group, carboxyl group, nitro group, hydroxamic acid group, sulfino group Hydrazino group, an imino group, a heterocyclic group or a silyl group. The retardation plate according to claim 1, wherein the optically anisotropic layer is formed using a liquid crystalline compound represented by the following general formula (II).
Formula (II)

In the general formula _{(II), Y 11, Y} 12, Y 13, Y 21, Y 22, Y 23, Y 24, Y 25, Y 26 represents a methine group or a nitrogen atom independently. X ₁ , X ₂ and X ₃ each independently represent an oxygen atom, a sulfur atom, methylene or imino. L ₁ , L ₂ and L ₃ each independently represents a single bond or a divalent linking group. R ₁ , R ₂ and R ₃ each independently represents the following general formula (V).
General formula (V)

In general formula (V), * represents the position bonded to the 5-membered ring in general formula (II). R ₄ each independently represents a halogen atom, an alkyl group having 1 to 8 carbon atoms, an alkyloxy group having 1 to 8 carbon atoms, an acyl group having 2 to 8 carbon atoms, an acyloxy group having 2 to 8 carbon atoms, An alkoxycarbonyl group having 2 to 8 carbon atoms, a nitro group, or a cyano group is represented. L ₆ represents ** — O—, ** — CO—O—, ** — O—CO—, ** — O—CO—O—, or ** — CH ₂ —, and ** represents a general formula It represents the position bonded to the benzene ring in (V). R ₅ represents a hydrogen atom, a methyl group, an ethyl group or a propyl group. m represents an integer of 2 to 16. l represents an integer of 0 to 4. R ₆ represents a hydrogen atom or a methyl group.   3. The retardation plate according to claim 1, further comprising an alignment film layer between the transparent support and at least one optically anisotropic layer.   The phase difference plate according to any one of claims 1 to 3, wherein the molecules of the liquid crystal compound are oriented and fixed with the angle formed by the disk surface of the molecule and the transparent support plane being substantially perpendicular.   5. The phase difference plate according to claim 3, wherein the molecules of the liquid crystal compound are aligned and fixed so that the angle formed by the disk surface of the molecule and the rubbing direction of the alignment layer is substantially orthogonal.   An image display device comprising a liquid crystal cell and the retardation plate according to claim 1. The image display device according to claim 6, wherein the liquid crystal cell is in an IPS (In-Plane Switching) mode.

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