JP2006106105A - Optical compensation sheet, liquid crystal display device, and manufacturing method of optical compensation sheet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical compensation sheet having an optical anisotropic layer in which the slope angle of a liquid crystal compound to be hybrid-oriented is precisely controlled. <P>SOLUTION: The optical compensation sheet consists of an optical anisotropic layer at least, and the optical anisotropic layer is formed by applying a liquid crystalline compound and a liquid crystalline composition containing at least a kind of compound among those expressed by a general formula (I) described below onto an alignment film formed by applying an alignment film composition of pH 6 or more onto a supporting body. The general formula (I): (Rf-Y-)<SB>m</SB>Ar(-W)<SB>n</SB>. In the general formula (I), Ar expresses a (m+n)-valent aromatic heterocycle or aromatic hydrocarbon ring; Y expresses a single bond or a divalent linkage group; Rf expresses an alkyl group or an alkyl group replaced by a fluorine atom; W expresses a sulfo group or a carboxyl group; m is an integer of 1 through 4; and n expresses 1 or 2. When m expresses an integer of two or more, two or more pieces of Rf an Y may be the same or different. When n is 2, each W may be the same. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a novel optical compensation sheet, a liquid crystal display device, and a method for manufacturing the optical compensation sheet.

Optical compensation sheets are used in various liquid crystal display devices in order to eliminate image coloring and expand the viewing angle. Conventionally, stretched birefringent films have been used as optical compensation sheets.In recent years, instead of stretched birefringent films, optical compensation sheets having an optically anisotropic layer made of a discotic liquid crystalline compound on a support are used. It is proposed to use. This optically anisotropic layer is usually formed by applying a liquid crystalline composition containing a discotic liquid crystalline compound on an alignment film, and heating it to a temperature higher than the alignment temperature to align the discotic liquid crystalline compound. It is formed by fixing the state.
In general, the discotic liquid crystalline compound has a large birefringence and various alignment forms. By using a discotic liquid crystalline compound, it has become possible to realize optical properties that cannot be obtained with conventional stretched birefringent films.

  On the other hand, since various orientation forms exist in the discotic liquid crystalline compound, it is necessary to control the orientation of the discotic liquid crystalline compound in the optically anisotropic layer in order to develop desired optical characteristics. In particular, in order to develop optical compensation performance, it is important to realize a so-called “hybrid alignment” state in which the tilt angle of the discotic liquid crystalline compound is aligned with the distance from the support surface. It is the most important factor that determines the performance of the compensation sheet, that is, the viewing angle expansion, the contrast reduction due to the viewing angle change, the gradation inversion, the black-and-white inversion, and the hue change. This hybrid alignment is the difference between the inclination angle of the alignment film surface provided on the support for the purpose of regulating the azimuth angle of the orientation of the discotic liquid crystalline compound and the inclination angle of the air side interface which is the outermost surface of the optical compensation sheet. It is realized by using. After applying and drying an optical compensation sheet using a discotic liquid crystalline compound, the discotic liquid crystalline compound is monodomain aligned at a stable tilt angle at both the air interface and the alignment film interface. As a result, an alignment state in which the inclination angle continuously changes in the thickness direction of the film is formed. The discotic liquid crystalline compound has a property of having a high tilt angle of 50 ° or more at the air interface. Therefore, in order to realize hybrid alignment, the tilt angle of the alignment film interface must be significantly smaller than the tilt angle of the air interface. An alignment film using polyvinyl alcohol is suitably used for realizing the target hybrid alignment because the inclination angle is close to 0 ° (see, for example, Patent Document 1).

  In order to obtain a desired optical compensation function, it is necessary to precisely control the inclination angle on the air interface side. As a method of obtaining an angle exceeding 50 ° which is an inclination angle obtained at a normal air interface, a method of adding a partially esterified cellulose (see, for example, Patent Document 2) or a fluorine-substituted alkyl group and a hydrophilic group (a sulfo group is a linking group) There has been proposed a method of adding a compound having a bond to a benzene ring via (see, for example, Patent Document 3). However, when the present inventors actually used these optical compensation sheets, light leakage from the oblique direction of the polarizing plate was observed, and the viewing angle did not expand sufficiently (to the extent that could be expected theoretically). It turns out that there is also. One reason for the insufficient optical compensation function is that the tilt angle of the discotic liquid crystalline compound is not sufficiently controlled.

  Further, when the alignment state of the liquid crystal compound is fixed, if the alignment state changes greatly due to a temperature change, it becomes difficult to precisely control the optical performance. For this reason, it has been required to maintain the orientation state stably in the vicinity of the fixing temperature regardless of the temperature.

  Furthermore, in the prior art, an optical compensation sheet has been developed mainly assuming a small or medium-sized liquid crystal display device of 15 inches or less. However, recently, it is also necessary to assume a liquid crystal display device having a large size of 17 inches or more and high brightness. When a conventional optical compensation sheet was attached as a protective film to a polarizing plate of a large liquid crystal display device, it was found that unevenness occurred on the panel. This defect is not so conspicuous in a small-sized or medium-sized liquid crystal display device, but it is necessary to further develop an optical film that copes with light leakage unevenness in response to an increase in size and brightness. As a technique for improving unevenness, a method of incorporating a leveling agent into a polymerizable liquid crystal has been disclosed (see, for example, Patent Document 4, pages 7-10). However, this method is effective only when the polymerizable liquid crystal has a homogeneous alignment, and cannot be applied to a complicated alignment such as a hybrid alignment.

JP-A-8-50206 JP-A-8-95030 JP 2001-330725 A JP-A-11-148080

  The present invention has been made in view of the above-mentioned problems. For example, an object of the present invention is to provide an optical compensation sheet having an optically anisotropic layer in which the tilt angle of a liquid crystal compound that is hybrid-aligned is precisely controlled. To do. Another object of the present invention is to provide a novel optical compensation sheet that has an excellent optical compensation function and has a wide viewing angle expansion performance when applied to an image display device, and a method for manufacturing the same. It is another object of the present invention to provide an optical compensation sheet that contributes to improving display quality without causing unevenness even when applied to a large liquid crystal display device. Another object of the present invention is to provide a liquid crystal display device having excellent viewing angle characteristics and high display quality.

Means for solving the above problems are as follows.
(1) At least composed of an optically anisotropic layer, and the optically anisotropic layer has a liquid crystalline compound and the following general formula on an alignment film obtained by applying an alignment film composition having a pH of 6 or more on a support. An optical compensation sheet obtained by applying a liquid crystalline composition containing at least one compound represented by (I).
Formula (I)
(Rf-Y-) _m Ar (-W) _n
(In general formula (I), Ar represents an (m + n) -valent aromatic heterocycle or aromatic hydrocarbon ring, Y represents a single bond or a divalent linking group, and Rf is substituted with an alkyl group or a fluorine atom. W represents a sulfo group or a carboxyl group, m represents an integer of 1 to 4, and n represents 1 or 2. When m represents an integer of 2 or more, a plurality of Rf and Y may be the same or different.When n is 2, each W may be the same or different.)
(2) The optical compensation sheet according to (1), wherein the optically anisotropic layer further contains a fluoroaliphatic group-containing polymer.
(3) The optical compensation sheet according to (1) or (2), wherein the optically anisotropic layer further contains a cellulose ester.
(4) The optical compensation sheet according to (1), wherein the optically anisotropic layer further contains a fluoroaliphatic group-containing polymer and a cellulose ester.
(5) The optical compensation sheet according to any one of (1) to (4), wherein the optically anisotropic layer further contains a compound having a 1,3,5-triazine ring group.
(6) The optical compensation sheet according to any one of (1) to (5), wherein the liquid crystalline compound is a discotic liquid crystalline compound.
(7) The optical compensation sheet according to any one of (1) to (6), wherein the optically anisotropic layer is formed from a liquid crystal compound having a hybrid alignment, and the hybrid alignment is fixed.
(8) A liquid crystal display device having the optical compensation sheet according to any one of (1) to (7).
(9) Any of (1) to (7) including a step of horizontally aligning a liquid crystalline compound, a step of hybrid aligning the liquid crystalline compound, and a step of fixing the liquid crystalline compound in the hybrid alignment state A method for producing the optical compensation sheet according to 1.
(10) A step of forming an alignment film by applying an alignment film composition having a pH of 6 or more on the support, and the liquid crystal compound and the following general formula (I) are expressed on the alignment film. A method for producing an optical compensation sheet according to any one of (1) to (7), comprising applying a liquid crystalline composition containing at least one compound to form an optically anisotropic layer.

  By using the optical compensation sheet of the present invention, the viewing angle of the liquid crystal display device can be expanded, and even in a large liquid crystal display device, an image with high display quality can be displayed without causing unevenness. Further, according to the method for producing an optical compensation sheet having the optically anisotropic layer of the present invention, the alignment aging time can be shortened compared to the conventional production method, and the change in retardation due to temperature change is small. The production efficiency of the compensation sheet can be significantly improved.

  Hereinafter, the contents of the present invention will be described in detail. In the present specification, “to” is used to mean that the numerical values described before and after it are included as a lower limit value and an upper limit value.

  The term “hybrid alignment” in the present invention refers to a so-called major axis direction of a liquid crystal compound (for example, a disk surface of a core in the case of a discotic liquid crystal compound) and a horizontal plane of the liquid crystal layer (for example, a liquid crystal layer is formed on a support). In this case, the angle formed with the surface of the support (hereinafter referred to as “tilt angle”) refers to an orientation that continuously changes in the thickness direction of the liquid crystal layer. In addition, “horizontal alignment” refers to the long axis direction (for example, discotic liquid crystallinity) of the liquid crystalline compound with respect to the horizontal plane of the liquid crystal layer (for example, the surface of the support when the liquid crystal layer is formed on the support). In the case of a compound, it means that the disk surface of the core is parallel, but it is not required to be strictly parallel. In this specification, the inclination angle formed between the major axis direction of the liquid crystalline compound and the horizontal plane Means an orientation of less than 10 degrees. In the step of horizontally aligning the liquid crystal compound, the inclination angle when the liquid crystal compound is horizontally aligned is preferably 5 degrees or less, more preferably 3 degrees or less, further preferably 2 degrees or less, and most preferably 1 degree or less. . The inclination angle may be 0 degree.

  The compound represented by the general formula (I) is also included in the expression “containing the compound represented by the general formula (I)” with respect to the compound polymerized by light, heat or the like. Hereinafter, unless otherwise noted in this specification, the same applies.

  The optical compensation sheet of the present invention is an optical compensation sheet having an optically anisotropic layer containing at least a liquid crystalline compound and a compound represented by the general formula (I). Preferably, it is an optical compensation sheet in which an optically anisotropic layer is provided on a support.

1. Optically anisotropic layer First, the optically anisotropic layer provided on the support will be described. The optically anisotropic layer is preferably designed so as to compensate for the liquid crystalline compound in the liquid crystal cell in the black display of the liquid crystal display device. The alignment state of the liquid crystal compound in the liquid crystal cell in black display varies depending on the mode of the liquid crystal display device. With respect to the alignment state of the liquid crystal compound in the liquid crystal cell, for example, those described in Abstracts of 2000 Display International Workshop (IDW '00), FMC7-2, P411 to 414 can be employed.

1-1. Inclination angle controlling agent (compound represented by formula (I))
The optical compensation sheet of the present invention contains a compound represented by the following general formula (I) in the optically anisotropic layer. The compound has a function as a tilt angle controlling agent of the liquid crystal compound.

Formula (I)
(Rf-Y-) _m Ar (-W) _n
(In general formula (I), Ar represents an (m + n) -valent aromatic heterocycle or aromatic hydrocarbon ring, Y represents a single bond or a divalent linking group, and Rf is substituted with an alkyl group or a fluorine atom. W represents a sulfo group or a carboxyl group, m represents an integer of 1 to 4, and n represents 1 or 2. When m represents an integer of 2 or more, a plurality of Rf and Y may be the same or different.When n is 2, each W may be the same or different.)

In the general formula (I), the aromatic heterocycle represented by Ar is preferably an aromatic heterocycle having 1 to 30 carbon atoms, more preferably 1 to 12 carbon atoms, such as a nitrogen atom, an oxygen atom, or a sulfur atom. A hetero ring having a hetero atom such as furan ring, pyrrole ring, imidazole ring, pyrazole ring, isoxazole ring, pyridine ring, pyrimidine ring, 1,3,5-triazine ring, indole ring, indazole ring, quinoline ring, A carbazole ring is preferred. The aromatic hydrocarbon ring represented by Ar is preferably an aromatic hydrocarbon ring having 6 to 30 carbon atoms, more preferably 6 to 20 carbon atoms, and most preferably a benzene ring.
Ar is more preferably an aromatic hydrocarbon ring.

The aromatic heterocycle or aromatic hydrocarbon ring represented by Ar may have a substituent, and examples of the substituent include the following groups.
An alkyl group (preferably an alkyl group having 1 to 20 carbon atoms, more preferably 1 to 12 carbon atoms, particularly preferably 1 to 8 carbon atoms, such as a methyl group, an ethyl group, an isopropyl group, a tert-butyl group, n-octyl group, n-decyl group, n-hexadecyl group, cyclopropyl group, cyclopentyl group, cyclohexyl group and the like, alkenyl group (preferably having 2 to 20 carbon atoms, more preferably 2 to 12 carbon atoms, Particularly preferred are alkenyl groups having 2 to 8 carbon atoms, such as vinyl group, aryl group, 2-butenyl group and 3-pentenyl group), alkynyl groups (preferably having 2 to 20 carbon atoms, more preferred). Is an alkynyl group having 2 to 12 carbon atoms, particularly preferably 2 to 8 carbon atoms, such as propargyl group and 3-pentynyl group. An aryl group (preferably an aryl group having 6 to 30 carbon atoms, more preferably 6 to 20 carbon atoms, particularly preferably 6 to 12 carbon atoms, such as a phenyl group, a p-methylphenyl group, and a naphthyl group. A substituted or unsubstituted amino group (preferably an amino group having 0 to 20 carbon atoms, more preferably 0 to 10 carbon atoms, and particularly preferably 0 to 6 carbon atoms. Group, methylamino group, dimethylamino group, diethylamino group, anilino group, etc.),

An alkoxy group (preferably having 1 to 20 carbon atoms, such as a methoxy group, an ethoxy group or a butoxy group), an alkoxycarbonyl group (preferably having 2 to 20 carbon atoms, more preferably having 2 to 16 carbon atoms, Particularly preferably, it has 2 to 10 carbon atoms, and examples thereof include methoxycarbonyl group and ethoxycarbonyl group), acyloxy group (preferably 2 to 20 carbon atoms, more preferably 2 to 16 carbon atoms, particularly preferably 2 carbon atoms). For example, an acetoxy group, a benzoyloxy group, and the like), an acylamino group (preferably having 2 to 20 carbon atoms, more preferably 2 to 16 carbon atoms, and particularly preferably an acylamino group having 2 to 10 carbon atoms). For example, acetylamino group, benzoylamino group, etc.), alkoxycarbonylamino A group (preferably an alkoxycarbonylamino group having 2 to 20 carbon atoms, more preferably 2 to 16 carbon atoms, particularly preferably 2 to 12 carbon atoms, such as a methoxycarbonylamino group), aryloxycarbonyl An amino group (preferably an aryloxycarbonylamino group having 7 to 20 carbon atoms, more preferably 7 to 16 carbon atoms, particularly preferably 7 to 12 carbon atoms, such as a phenyloxycarbonylamino group); A sulfonylamino group (preferably a sulfonylamino group having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms, and examples thereof include a methanesulfonylamino group and a benzenesulfonylamino group. ), A sulfamoyl group (preferably having 0 to 20 carbon atoms, more preferably Or a sulfamoyl group having 0 to 16 carbon atoms, particularly preferably 0 to 12 carbon atoms, and examples thereof include a sulfamoyl group, a methylsulfamoyl group, a dimethylsulfamoyl group, and a phenylsulfamoyl group). A carbamoyl group (preferably a carbamoyl group having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms, such as an unsubstituted carbamoyl group, a methylcarbamoyl group, a diethylcarbamoyl group, Phenylcarbamoyl group, etc.),

An alkylthio group (preferably an alkylthio group having 1 to 20 carbon atoms, more preferably an alkylthio group having 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms, such as a methylthio group and an ethylthio group), an arylthio group ( Preferably it is C6-C20, More preferably, it is C6-C16, Most preferably, it is C6-C12 arylthio group, for example, a phenylthio group etc. are mentioned, A sulfonyl group (preferably C1-C1). 20, more preferably a sulfonyl group having 1 to 16 carbon atoms, particularly preferably a sulfonyl group having 1 to 12 carbon atoms, such as a mesyl group and a tosyl group, and a sulfinyl group (preferably having a carbon number of 1 to 20, more A sulfinyl group having 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms is preferable. Zensulfinyl group and the like), ureido group (preferably a ureido group having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms, for example, an unsubstituted ureido group , Methylureido group, phenylureido group, etc.), phosphoric acid amide group (preferably having 1 to 20 carbon atoms, more preferably having 1 to 16 carbon atoms, particularly preferably having 1 to 12 carbon atoms). Yes, for example, diethyl phosphoric acid amide group, phenyl phosphoric 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 (preferably having a carbon number of 1 to 0, more preferably a heterocyclic group of 1 to 12, for example, a heterocyclic group having a heteroatom such as a nitrogen atom, an oxygen atom, a sulfur atom, such as an imidazolyl group, a pyridyl group, a quinolyl group, a furyl group , Piperidyl group, morpholino group, benzoxazolyl group, benzimidazolyl group, benzthiazolyl group and the like), silyl group (preferably having 3 to 40 carbon atoms, more preferably 3 to 30 carbon atoms, particularly preferably A silyl group having 3 to 24 carbon atoms, and examples thereof include a trimethylsilyl group and a triphenylsilyl group).
These substituents may be further substituted with these substituents. Further, when two or more substituents are present, they may be the same or different. If possible, they may be bonded to each other to form a ring.

  As the substituent other than —Y—Rf and W of the aromatic heterocycle or aromatic hydrocarbon ring represented by Ar, preferably an alkyl group, an aryl group, an alkoxy group, an alkoxycarbonyl group, an acyloxy group, an acylamino group, A sulfonylamino group and an alkylthio group, particularly preferably an alkyl group, an alkoxy group, an alkoxycarbonyl group, and an acyloxy group. Most preferably, Ar is not substituted with a substituent other than —Y—Rf and W.

In the general formula (I), Y represents a divalent linking group or a single bond. In the case of a divalent linking group, an alkylene group, an alkenylene group, a divalent aromatic group, a divalent heterocyclic residue, -CO-, -NR ^a- (R ^a has 1 to And a divalent linking group selected from the group consisting of —O—, —S—, —SO—, —SO ₂ — and combinations thereof. The divalent linking group is a group in which at least two divalent linking groups selected from an alkylene group, —CO—, —NR ^a —, —O—, —S—, —SO ₂ — and a group thereof are combined. It is more preferable that The alkylene group preferably has 1 to 12 carbon atoms. The alkenylene group preferably has 2 to 12 carbon atoms. The number of carbon atoms in the arylene group is preferably 6-10. If possible, the alkylene group, alkenylene group and arylene group may be substituted by a group exemplified as the substituent of the aforementioned Ar (eg, alkyl group, halogen atom, cyano, alkoxy group, acyloxy group, etc.). .
Y is preferably a divalent linking group, and particularly preferably a divalent linking group selected from the group consisting of an alkylene group, —O—, —S—, and combinations thereof.

  In the general formula (I), the alkyl group substituted with a fluorine atom represented by Rf may have a cyclic structure or a branched structure. It is preferably 1 to 20 carbon atoms, more preferably 4 to 16 carbon atoms, and particularly preferably 4 to 12 carbon atoms.

In the alkyl group substituted with a fluorine atom represented by Rf, the substitution rate of the fluorine atom is preferably such that 50% or more of the hydrogen atoms contained in the alkyl group are substituted with a fluorine atom, and 60% or more are substituted. More preferably. Rf preferably has a CF ₃ group or a CF ₂ H group at its end, and particularly preferably a CF ₃ group. If possible, the alkyl group substituted with a fluorine atom represented by Rf is, if possible, a group exemplified as the substituent of Ar described above (eg, alkyl group, halogen atom, cyano group, alkoxy group, acyloxy group, etc.). May be substituted.
Specific examples of Rf are shown below.

Rf1: n-C ₈ F ₁₇ −
_{Rf2: n-C 6 F 13} -
_{Rf3: n-C 4 F 9} -
_{Rf4: n-C 8 F 17} - (CH 2) 2 -
_{Rf5: n-C 6 F 13} - (CH 2) 2 -
_{Rf6: n-C 4 F 9} - (CH 2) 2 -
_{Rf7: n-C 8 F 17} - (CH 2) 3 -
_{Rf8: n-C 6 F 13} - (CH 2) 3 -
_{Rf9: n-C 4 F 9} - (CH 2) 3 -
_{Rf10: H- (CF 2) 8} -
Rf11: H— (CF ₂ ) ₆ —
Rf12: H— (CF ₂ ) ₄ —
_{Rf13: H- (CF 2) 8} - (CH 2) -
Rf14: H— (CF ₂ ) ₆ — (CH ₂ ) —
_{Rf15: H- (CF 2) 4} - (CH 2) -
_{Rf16: n-C 4 F 9} -CH 2 CH 2 - (n-C 4 F 9 -CH 2 CH 2 -) CHCH 2 -

  W is preferably a sulfo group, m is preferably 1 or 2, and n is preferably 1.

  Particularly preferably, the general formula (I) is the following general formula (Ia).

Formula (Ia)

In general formula (Ia), Y ² represents a single bond or a divalent linking group, and Rf ² represents an alkyl group substituted with a fluorine atom.

In the general formula (Ia), Y ² and Rf ² are the same meanings as Y and Rf in Formula (I), preferable ranges are also the same.

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

  The compound represented by the general formula (I) can be easily synthesized by combining a general alkylation reaction of a hydroxy group and a sulfonation reaction of an aromatic compound.

  The amount of the compound represented by the general formula (I) is preferably 0.01 to 20% by mass, particularly preferably 0.05 to 10% by mass, and 0.05 to 1% by mass based on the amount of the liquid crystal compound. % Is most preferred. In this invention, 1 type of the compound represented by the said general formula (I) may be used, and 2 or more types may be used.

1-2. Liquid crystalline compound The liquid crystalline compound used for the optically anisotropic layer includes a rod-like liquid crystalline compound or a discotic liquid crystalline compound (discotic liquid crystalline compound). The rod-like liquid crystal compound or the discotic liquid crystal compound may be a high-molecular liquid crystal or a low-molecular liquid crystal, and further includes those in which the low-molecular liquid crystal is cross-linked and no longer exhibits liquid crystallinity. A rod-like liquid crystal compound and a discotic liquid crystal compound may be used in combination. More preferably, it is a discotic liquid crystalline compound.

[Bar-shaped liquid crystalline compound]
Examples of rod-like liquid crystalline compounds include azomethines, azoxys, cyanobiphenyls, cyanophenyl esters, benzoic acid esters, cyclohexanecarboxylic acid phenyl esters, cyanophenylcyclohexanes, cyano-substituted phenylpyrimidines, alkoxy-substituted phenylpyrimidines. , Phenyldioxanes, tolanes and alkenylcyclohexylbenzonitriles are preferably used.
The rod-like liquid crystalline compound includes a metal complex. Moreover, the liquid crystal polymer which contains a rod-shaped liquid crystalline compound in a repeating unit can also be used as a rod-shaped liquid crystalline compound. In other words, the rod-like liquid crystalline compound may be bonded to a (liquid crystal) polymer.
For rod-like liquid crystalline compounds, see Chapter 4, Chapter 7 and Chapter 11 of the Chemistry of the Quarterly Chemical Review Vol. 22 Liquid Crystal Chemistry (1994) edited by the Chemical Society of Japan, and the 142nd Committee of the Japan Society for the Promotion of Science. Described in Chapter 3.
The birefringence of the rod-like liquid crystalline compound is preferably in the range of 0.001 to 0.7.
The rod-like liquid crystalline compound preferably has a polymerizable group in order to fix its alignment state. The polymerizable group is preferably a radically polymerizable unsaturated group or a cationically polymerizable group. Specifically, for example, the polymerizable group described in paragraphs [0064] to [0086] of JP-A-2002-62427 is described. And polymerizable liquid crystalline compounds.

[Discotic liquid crystalline compounds]
Examples of discotic liquid crystalline compounds include C.I. Destrade et al., Mol. Cryst. 71, 111 (1981), benzene derivatives described in C.I. Destrade et al., Mol. Cryst. 122, 141 (1985), Physics lett, A, 78, 82 (1990); Kohne et al., Angew. Chem. 96, page 70 (1984) and the cyclohexane derivatives described in J. Am. M.M. Lehn et al. Chem. Commun. , 1794 (1985), J. Am. Zhang et al., J. Am. Chem. Soc. 116, 2655 (1994), azacrown type and phenylacetylene type macrocycles are included.

  As a discotic liquid crystalline compound, a compound having liquid crystallinity in which a linear alkyl group, an alkoxy group, and a substituted benzoyloxy group are radially substituted as a side chain of the mother nucleus with respect to the mother nucleus at the center of the molecule Is also included. The molecule or the assembly of molecules is preferably a compound having rotational symmetry and imparting a certain orientation. The optically anisotropic layer formed from the discotic liquid crystalline compound does not necessarily require that the compound finally contained in the optically anisotropic layer is a discotic liquid crystalline compound. Also included are compounds that have a group that reacts with heat or light, and that eventually polymerize or cross-link by reaction with heat or light to increase the molecular weight and lose liquid crystallinity. Preferred examples of the discotic liquid crystalline compound are described in JP-A-8-50206. The polymerization of discotic liquid crystalline compounds is described in JP-A-8-27284.

  In order to fix the discotic liquid crystalline compound by polymerization, it is necessary to bond a polymerizable group as a substituent to the discotic core of the discotic liquid crystalline compound. A compound in which the discotic core and the polymerizable group are bonded via a linking group is preferable, and the orientation state can be maintained even in the polymerization reaction. Examples thereof include compounds described in paragraphs [0151] to “0168” in JP-A No. 2000-155216.

  In hybrid alignment, the angle between the long axis (disc surface) of the discotic liquid crystalline compound and the plane of the polarizing film increases or decreases in the depth direction of the optically anisotropic layer and with increasing distance from the plane of the polarizing film. is doing. The angle preferably decreases with increasing distance. Further, the change in angle can be a continuous increase, a continuous decrease, an intermittent increase, an intermittent decrease, a change including a continuous increase and a continuous decrease, or an intermittent change including an increase and a decrease. The intermittent change includes a region where the inclination angle does not change in the middle of the thickness direction. Even if the angle includes a region where the angle does not change, the angle only needs to increase or decrease as a whole. Furthermore, it is preferable that the angle changes continuously.

  The average direction of the major axis of the discotic liquid crystalline compound on the polarizing film side can be generally adjusted by selecting the discotic liquid crystalline compound or the material of the alignment film, or by selecting the rubbing treatment method. Further, the major axis (disk surface) direction of the discotic liquid crystalline compound on the surface side (air side) is generally adjusted by selecting the discotic liquid crystalline compound or the type of additive used together with the discotic liquid crystalline compound. be able to. Examples of the additive used together with the discotic liquid crystalline compound include, in addition to the compound represented by the general formula (I), a fluoropolymer, a triazine ring group-containing compound, a cellulose ester described later, and a plasticizer. , Surfactants, polymerizable monomers and polymers. The degree of change in the orientation direction of the major axis can be adjusted by selecting the liquid crystal compound and the additive as described above.

  The discotic nematic liquid crystal phase-solid phase transition temperature of the discotic liquid crystalline compound is preferably 70 to 300 ° C, more preferably 70 to 170 ° C.

1-3. Fluoropolymer The optical compensation sheet of the present invention preferably contains a fluoroaliphatic group-containing copolymer (sometimes abbreviated as “fluorine polymer”) in the optically anisotropic layer. The fluoropolymer functions as an unevenness preventing agent for optical films. Therefore, by applying the optical film to a large liquid crystal display device, it is possible to display an image with high display quality without causing unevenness.

Hereinafter, the fluoropolymer according to the present invention will be described in detail.
The fluoropolymer used in the present invention is an acrylic resin, a methacrylic resin containing a repeating unit derived from a monomer represented by the following general formula (II), or a repeating unit derived from a monomer represented by the following general formula (II) An acrylic resin and a methacrylic resin containing a repeating unit derived from a monomer represented by the following general formula (III) are preferable, and an acrylic resin or a methacrylic resin copolymerized with a vinyl monomer copolymerizable with these monomers. Acrylic resins are also preferred.

In the general formula (II), R ¹⁰ represents a hydrogen atom or a methyl group, X ¹⁰ represents an oxygen atom, a sulfur atom or —N (R ¹¹ ) —, Hf represents a hydrogen atom or a fluorine atom, and r represents 1 Represents an integer of ˜6, s represents an integer of 2 to 4, and R ¹¹ represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms.

Furthermore, X ¹⁰ is preferably an oxygen atom. r is particularly preferably 1 or 2. s is preferably 2 or 3, and a mixture thereof may be used. R ¹¹ specifically represents a methyl group, an ethyl group, a propyl group, or a butyl group, and preferably a hydrogen atom or a methyl group.

  Although the example of the more specific monomer of the fluoro aliphatic group containing monomer represented by general formula (II) is given to the following, it is not this limitation.

In the general formula (III), R ²⁰ represents a hydrogen atom or a methyl group, Y ²⁰ represents a divalent linking group, and R ²¹ represents a poly (alkyleneoxy) group or a substituent which may have a substituent. A linear, branched or cyclic alkyl group having 1 to 20 carbon atoms which may be present.

Furthermore, the divalent linking group for Y ²⁰ is preferably an oxygen atom, a sulfur atom or N (R ²² ) —. R ²² is preferably a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, such as a methyl group, an ethyl group, a propyl group, or a butyl group. More preferred forms of R ²² are a hydrogen atom and a methyl group. Y ²⁰ is more preferably an oxygen atom, —N (H) — or N (CH ₃ ) —.

The poly (alkyleneoxy) group in the general formula (III) can be represented by (R ²³ O) _x , where R ²³ is an alkylene group having 2 to 4 carbon atoms, such as —CH ₂ CH ₂ —, It is preferably —CH ₂ CH ₂ CH ₂ —, —CH (CH ₃ ) CH ₂ —, or —CH (CH ₃ ) CH (CH ₃ ) —.
The alkyleneoxy units in the poly (alkyleneoxy) group may be the same as in poly (propyleneoxy), or two or more different types of alkyleneoxy may be randomly distributed. It may be a linear or branched propyleneoxy or ethyleneoxy unit, or may be present as a linear or branched propyleneoxy unit block and an ethyleneoxy unit block.
In this poly (alkyleneoxy) chain, a plurality of poly (alkyleneoxy) units are linked to each other by one or more chain bonds (for example, -CONH-Ph-NHCO-, -S-, etc., where Ph represents a phenylene group) ) Can be included. If the linkage in the chain has a valence of 3 or more, this provides a means for obtaining branched alkyleneoxy units. When this copolymer is used in the present invention, the molecular weight of the poly (alkyleneoxy) group is suitably from 250 to 3,000.

Examples of the linear, branched or cyclic alkyl group having 1 to 20 carbon atoms represented by R ²¹ include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, which may be linear and branched, Heptyl group, octyl group, nonyl group, decyl group, undecyl group, dodecyl group, tridecyl group, tetradecyl group, pentadecyl group, octadecyl group, eicosanyl group, etc., and monocyclic cycloalkyl groups such as cyclohexyl group, cycloheptyl group and the like A polycyclic cycloalkyl group such as a bicycloheptyl group, a bicyclodecyl group, a tricycloundecyl group, a tetracyclododecyl group, an adamantyl group, a norbornyl group, or a tetracyclodecyl group is preferably used.

Examples of the substituent of the poly (alkyleneoxy) group or alkyl group represented by R ²¹ include a hydroxyl group, an alkylcarbonyl group, an arylcarbonyl group, an alkylcarbonyloxy group, a carboxyl group, an alkyl ether group, an aryl ether group, a fluorine atom, Examples include, but are not limited to, halogen atoms such as chlorine atom and bromine atom, nitro group, cyano group and amino group.

  The monomer represented by the general formula (III) is particularly preferably alkyl (meth) acrylate or poly (alkyleneoxy) (meth) acrylate.

  Specific examples of the monomer represented by the general formula (III) are shown below, but not limited thereto.

  One of the fluoroaliphatic groups in the fluoropolymer according to the present invention is derived from, for example, a fluoroaliphatic compound produced by a telomerization method (also referred to as a telomer method) or an oligomerization method (also referred to as an oligomer method). It will be. Regarding the production method of these fluoroaliphatic compounds, for example, “Synthesis and function of fluorine compounds” (supervision: Nobuo Ishikawa, published by CMC Co., 1987), “Chemistry of Organic Fluorine Compounds” II "(Monograph 187, Ed by Milos Hudlicky and Attila E. Pavlath, American Chemical Society 1995), pages 747-752. The telomerization method is a method of synthesizing a telomer by radical polymerization of a fluorine-containing vinyl compound such as tetrafluoroethylene using an alkyl halide having a large chain transfer constant such as iodide as a telogen (example in Scheme-1). showed that).

  The obtained terminal iodinated telomer is usually subjected to appropriate terminal chemical modification such as [Scheme2], and led to a fluoroaliphatic compound. These compounds are further converted into a desired monomer structure as necessary, and used for the production of a fluoroaliphatic group-containing polymer.

Poly (alkyleneoxy) acrylate and methacrylate are commercially available hydroxypoly (alkyleneoxy) materials such as “Pluronic” (Pluronic (Asahi Denka Kogyo Co., Ltd.)), “Adeka Polyether” (Asahi Denka Kogyo ( “Carbowax” [Carbowax], “Triton” [Toriton (Rohm and Haas)) and “PEG” (Daiichi Kogyo Seiyaku Co., Ltd.) It can be produced by reacting a commercially available product with acrylic acid, methacrylic acid, acrylic chloride, methacrylic chloride or acrylic acid anhydride by a known method.
Separately, poly (oxyalkylene) diacrylate produced by a known method can also be used.

  As the fluoropolymer in the present invention, a homopolymer of a monomer represented by the general formula (II) or a copolymer of a monomer represented by the general formula (II) and a polyalkyleneoxy (meth) acrylate is preferable, and polyethylene It is particularly preferred to include oxy (meth) acrylate or polypropyleneoxy (meth) acrylate.

  The copolymer of the monomer represented by the general formula (II) and the monomer represented by the general formula (III) used in the present invention is added with a monomer copolymerizable with these in addition to the above monomers. It may be a copolymer reacted in the above manner. A preferable copolymerization ratio of the copolymerizable monomer is 20 mol% or less, more preferably 10 mol% or less in all monomers. Such monomers include Polymer Handbook 2nd ed. , J .; Brandrup, Wiley lnterscience (1975) Chapter 2 Pages 1-483 can be used. For example, a compound having one addition polymerizable unsaturated bond selected from acrylic acid, methacrylic acid, acrylic esters, methacrylic esters, acrylamides, methacrylamides, allyl compounds, vinyl ethers, vinyl esters, etc. I can give you.

Specifically, the following monomers can be mentioned.
Acrylic esters:
Furfuryl acrylate, tetrahydrofurfuryl acrylate, etc.
Methacrylic acid esters:
Furfuryl methacrylate, tetrahydrofurfuryl methacrylate, etc.

Allyl compounds:
Allyl esters (for example, allyl acetate, allyl caproate, allyl caprylate, allyl laurate, allyl palmitate, allyl stearate, allyl benzoate, allyl acetoacetate, allyl lactate, etc.), allyloxyethanol, etc.

Vinyl ethers:
Alkyl vinyl ethers (eg hexyl vinyl ether, octyl vinyl ether, decyl vinyl ether, ethyl hexyl vinyl ether, methoxyethyl vinyl ether, ethoxyethyl vinyl ether, chloroethyl vinyl ether, 1-methyl-2,2-dimethylpropyl vinyl ether, 2-ethylbutyl vinyl ether, hydroxyethyl vinyl ether, Diethylene glycol vinyl ether, dimethylaminoethyl vinyl ether, diethylaminoethyl vinyl ether, butylaminoethyl vinyl ether, benzyl vinyl ether, tetrahydrofurfuryl vinyl ether, etc.

Vinyl esters:
Vinyl bitylate, vinyl isobutyrate, vinyl trimethyl acetate, vinyl diethyl acetate, vinyl valerate, vinyl caproate, vinyl chloroacetate, vinyl dichloroacetate, vinyl methoxyacetate, vinyl butoxyacetate, vinyl lactate, vinyl-β-phenyl Butyrate, vinyl cyclohexyl carboxylate, etc.

Dialkyl itaconates:
Dimethyl itaconate, diethyl itaconate, dibutyl itaconate, etc.
Dialkyl or monoalkyl esters of fumaric acid:
Dibutyl fumarate etc. Others such as crotonic acid, itaconic acid, acrylonitrile, methacrylonitrile, maleilonitrile, styrene.

The amount of the fluoroaliphatic group-containing monomer represented by the general formula (II) in the fluoropolymer used in the present invention is preferably 5 mol% or more, more preferably 20 mol% of the total amount of the constituent monomers of the polymer. It is above, More preferably, it is 30 mol% or more.
The amount of the monomer represented by the general formula (III) in the fluoropolymer of the present invention is 5 mol% or more, preferably 5 to 70 mol%, more preferably 5 mol% of the total amount of the constituent monomers of the fluoropolymer. ~ 60 mol%.

The preferred weight average molecular weight of the fluoropolymer used in the present invention is preferably 3000 to 100,000, more preferably 6,000 to 80,000.
Furthermore, the preferable content of the fluoropolymer according to the present invention with respect to the liquid crystalline composition containing the liquid crystalline compound (coating component excluding the solvent) is in the range of 0.005 to 8% by mass, more preferably 0.8. The range is from 01 to 1% by mass, and more preferably from 0.05 to 0.5% by mass. By making the addition amount of the fluorine-based polymer within the above range, sufficient effects can be exhibited, the coating film is sufficiently dried, and the performance as an optical film (for example, uniformity of retardation, etc.) More preferred.

  The fluorine-based polymer used in the present invention can be produced by a known and conventional method. For example, a general-purpose radical polymerization initiator is added and polymerized in an organic solvent containing monomers such as (meth) acrylate having a fluoroaliphatic group and (meth) acrylate having a polyalkyleneoxy group. Can be manufactured. Further, in some cases, other addition-polymerizable unsaturated compounds can be further added and produced by the same method as described above. Depending on the polymerizability of each monomer, a dropping polymerization method in which a monomer and an initiator are added dropwise to a reaction vessel is also effective for obtaining a polymer having a uniform composition.

  Hereinafter, although the example of the specific structure of the fluorine-type polymer used by this invention is shown, this invention is not limited to these. In addition, the number in a formula shows the molar ratio of each monomer component. Mw represents a weight average molecular weight.

1-4. Horizontal alignment accelerator (compound having 1,3,5-triazine ring group)
The optical compensation sheet of the present invention preferably contains a compound having a 1,3,5-triazine ring group in the optically anisotropic layer. The compound contributes to stably transferring a liquid crystal compound, particularly a discotic liquid crystal compound, from a horizontal alignment state to a hybrid alignment state. The compound having a 1,3,5-triazine ring group that can be used in the present invention is preferably a compound represented by the following general formula (IV) or (V).

Formula (IV)

In the general formula (IV), L ⁴¹ , L ⁴² and L ⁴³ each represent a single bond or a divalent linking group, A ⁴¹ , A ⁴² and A ⁴³ each represent an alkylene group, t1, t2 and t3 Represents an integer of 0 or more. R ⁴¹ , R ⁴² and R ⁴³ are each an organic group. When t 1 is 0, R ⁴¹ is an alkyl group, when t 2 is 0, R ⁴² is an alkyl group, and when t 3 is 0, ⁴³ is an alkyl group.

In the general formula (IV), L ⁴¹ , L ⁴² and L ⁴³ are more preferably each a divalent linking group, and still more preferably NRa (Ra is a hydrogen atom, an alkyl group or an aryl group) Or O or S.
Examples of organic groups of R ⁴¹ , R ⁴² and R ⁴³ are alkyl groups (preferably alkyl groups having 1 to 20 carbon atoms, more preferably 1 to 12 carbon atoms, particularly preferably 1 to 8 carbon atoms, , Methyl group, ethyl group, isopropyl group, tert-butyl group, n-octyl group, n-decyl group, n-hexadecyl group, cyclopropyl group, cyclopentyl group, cyclohexyl group, etc.), alkenyl group (preferably An alkenyl group having 2 to 20 carbon atoms, more preferably 2 to 12 carbon atoms, particularly preferably 2 to 8 carbon atoms, and examples thereof include a vinyl group, an aryl group, a 2-butenyl group, and a 3-pentenyl group. ), An alkynyl group (preferably an alkynyl group having 2 to 20 carbon atoms, more preferably 2 to 12 carbon atoms, particularly preferably 2 to 8 carbon atoms, Propargyl group, 3-pentynyl group and the like), aryl groups (preferably 6-30 carbon atoms, more preferably 6-20 carbon atoms, particularly preferably 6-12 carbon atoms aryl groups such as phenyl Group, p-methylphenyl group, naphthyl group and the like), alkoxycarbonyl group (preferably having 2 to 20 carbon atoms, more preferably 2 to 16 carbon atoms, particularly preferably 2 to 10 carbon atoms, A methoxycarbonyl group, an ethoxycarbonyl group, and the like), a sulfonyl group (preferably a sulfonyl group having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, and particularly preferably 1 to 12 carbon atoms. Group, tosyl group and the like), sulfinyl group (preferably having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, Preferably it is a C1-C12 sulfinyl group, for example, a methanesulfinyl group, a benzenesulfinyl group, etc., a heterocyclic group (preferably C1-C30, more preferably 1-12 heterocyclic group) A heterocyclic group having a heteroatom such as a nitrogen atom, an oxygen atom or a sulfur atom, such as an imidazolyl group, a pyridyl group, a quinolyl group, a furyl group, a piperidyl group, a morpholino group, or a benzoxazolyl group. A benzimidazolyl group, a benzthiazolyl group, etc.), a silyl group (preferably a silyl group having 3 to 40 carbon atoms, more preferably 3 to 30 carbon atoms, and particularly preferably 3 to 24 carbon atoms. , Trimethylsilyl group, triphenylsilyl group and the like.

一般式（Ｖ）において、Ｚ⁵¹はｑ価の連結基を表す。ｑは２以上の整数を表す。Ｘ⁵¹はＮＲａ（Ｒａは水素原子、アルキル基またはアリール基を表す）、Ｏ、Ｓのいずれかを表し、複数のＸ⁵¹は同じでも異なっても良い。Ｒ⁵¹およびＲ⁵²は置換基を表し、同じでも異なっていてもよく、複数のＲ⁵¹およびＲ⁵²はそれぞれ同じでも異なっていてもよい。 General formula (V)

In the general formula (V), Z ⁵¹ represents a q-valent linking group. q represents an integer of 2 or more. X ⁵¹ represents NRa (Ra represents a hydrogen atom, an alkyl group or an aryl group), O, or S, and the plurality of X ⁵¹ may be the same or different. R ⁵¹ and R ⁵² represent a substituent, which may be the same or different, and a plurality of R ⁵¹ and R ⁵² may be the same or different.

In the general formula (V), the substituent represented by R ⁵¹ and R ⁵² is an alkyl group (a linear or branched substituted or unsubstituted alkyl group, preferably an alkyl group having 1 to 30 carbon atoms). For example, methyl group, ethyl group, n-propyl group, isopropyl group, tert-butyl group, n-octyl group, dodecyl group, eicosyl group, 2-chloroethyl group, 2-cyanoethyl group, 2-ethylhexyl group, 2-hexyl Xyldecyl group, 2-octyldodecyl group, 3- (2,4-di-tert-amylphenoxy) propyl group), cycloalkyl group (preferably a substituted or unsubstituted cycloalkyl group having 3 to 30 carbon atoms, such as A cyclohexyl group, a cyclopentyl group, a 4-n-dodecylcyclohexyl group, a polycycloalkyl group such as a bicycloal Group (preferably a substituted or unsubstituted bicycloalkyl group having 5 to 30 carbon atoms, for example, bicyclo [1.2.2] heptan-2-yl group, bicyclo [2.2.2] octane-3 -Yl group) and a tricyclic group such as a tricycloalkyl group, preferably a monocyclic cycloalkyl group or a bicycloalkyl group, and a monocyclic cycloalkyl group is particularly preferable.

  An alkenyl group (straight or branched substituted or unsubstituted alkenyl group, preferably an alkenyl group having 2 to 30 carbon atoms, such as vinyl group, allyl group, prenyl group, geranyl group, oleyl group), cycloalkenyl group Group (preferably a substituted or unsubstituted cycloalkenyl group having 3 to 30 carbon atoms, such as 2-cyclopenten-1-yl group and 2-cyclohexen-1-yl group, and polycycloalkenyl group such as A bicycloalkenyl group (preferably a substituted or unsubstituted bicycloalkenyl group having 5 to 30 carbon atoms such as bicyclo [2.2.1] hept-2-en-1-yl group, bicyclo [2.2 .2] Oct-2-en-4-yl group), tricycloalkenyl group, and monocyclic cycloalkenyl group are preferable. Group (preferably a substituted or unsubstituted alkynyl group having 2 to 30 carbon atoms, such as ethynyl group, propargyl group, trimethylsilyl ethynyl group),

  An aryl group (preferably a substituted or unsubstituted aryl group having 6 to 30 carbon atoms such as a phenyl group, p-tolyl group, naphthyl group, m-chlorophenyl group, o-hexadecanoylaminophenyl group, o-2- (Perfluorohexyl) ethoxyphenyl group, o-3- (perfluorohexyl) propyloxyphenyl group, o-2- (6H-dodecafluorohexyl) ethoxyphenyl group, o- (8H-hexadecafluorooctyl) methoxyphenyl Group), a heterocyclic group (preferably a 5- to 7-membered substituted or unsubstituted, saturated or unsaturated, aromatic or non-aromatic, monocyclic or condensed heterocyclic group, more preferably a ring-constituting atom. Is selected from a carbon atom, a nitrogen atom, and a sulfur atom, and any one of a nitrogen atom, an oxygen atom, and a sulfur atom A heterocyclic group having at least one tera atom, and more preferably a 5- or 6-membered aromatic heterocyclic group having 3 to 30 carbon atoms, such as 2-furyl group, 2-thienyl group, 2- Pyridyl group, 4-pyridyl group, 2-pyrimidinyl group, 2-benzothiazolyl group), cyano group, hydroxyl group, nitro group, carboxyl group,

  An alkoxy group (preferably a substituted or unsubstituted alkoxy group having 1 to 30 carbon atoms such as methoxy group, ethoxy group, isopropoxy group, tert-butoxy group, n-octyloxy group, 2-methoxyethoxy group, 1H, 1H, 9H-hexadecafluorononanoxy group, 2-perfluorohexylethoxy group), an aryloxy group (preferably a substituted or unsubstituted aryloxy group having 6 to 30 carbon atoms, such as a phenoxy group, 2-methylphenoxy group, 2,4-di-tert-amylphenoxy group, 4-tert-butylphenoxy group, 3-nitrophenoxy group, 2-tetradecanoylaminophenoxy group, o-2- (perfluorohexyl) Ethoxyphenoxy group, o-3- (perfluorohexyl) propyloxyphenoxy group O-2- (6H-dodecafluorohexyl) ethoxyphenoxy group, o- (8H-hexadecafluorooctyl) methoxyphenoxy group), silyloxy group (preferably a silyloxy group having 3 to 20 carbon atoms, for example, trimethylsilyl An oxy group, a tert-butyldimethylsilyloxy group), a heterocyclic oxy group (preferably a substituted or unsubstituted heterocyclic oxy group having 2 to 30 carbon atoms, and the heterocyclic portion was explained by the aforementioned heterocyclic group. Heterocyclic part is preferable, for example, 1-phenyltetrazol-5-oxy group, 2-tetrahydropyranyloxy group),

  Acyloxy group (preferably formyloxy group, substituted or unsubstituted alkylcarbonyloxy group having 2 to 30 carbon atoms, substituted or unsubstituted arylcarbonyloxy group having 6 to 30 carbon atoms, such as formyloxy group, acetyl Oxy group, pivaloyloxy group, stearoyloxy group, benzoyloxy, p-methoxyphenylcarbonyloxy), carbamoyloxy group (preferably a substituted or unsubstituted carbamoyloxy group having 1 to 30 carbon atoms, for example, N, N- Dimethylcarbamoyloxy group, N, N-diethylcarbamoyloxy group, morpholinocarbonyloxy group, N, N-di-n-octylaminocarbonyloxy group, Nn-octylcarbamoyloxy group), alkoxycarbonyloxy group (preferably ,carbon 2-30 substituted or unsubstituted alkoxycarbonyloxy groups such as methoxycarbonyloxy group, ethoxycarbonyloxy group, tert-butoxycarbonyloxy group, n-octylcarbonyloxy group), aryloxycarbonyloxy group (preferably carbon A substituted or unsubstituted aryloxycarbonyloxy group of 7 to 30, for example, phenoxycarbonyloxy group, p-methoxyphenoxycarbonyloxy group, pn-hexadecyloxyphenoxycarbonyloxy group),

  An amino group (preferably an amino group, a substituted or unsubstituted alkylamino group having 1 to 30 carbon atoms, a substituted or unsubstituted arylamino group having 6 to 30 carbon atoms, or a heterocyclic amino group having 0 to 30 carbon atoms); Yes, for example, amino group, methylamino group, dimethylamino group, 3-perfluorohexylpropylamino group, 3- (2,4-di-tert-amylphenoxy) propylamino group, 3- (2-ethylhexyloxy) Propylamino group, 3- (2-hexyldecanooxy) propylamino group, 3-dodecyloxypropylamino group, 3- (3-perfluorohexylpropyloxy) propylamino group, 3- (3- (6H-par Fluorohexyl) propyloxy) propylamino group, anilino group, N-methyl-anilino group, diphenylamino group 2-methyloxyanilino group, 2- (3-perfluorohexylpropyloxy) anilino group, 2- (2-perfluorobutylethyloxy) anilino group, 2,4-di (2-perfluorohexylethyloxy) Anilino group, 2- (6H-perfluorohexylmethyloxy) anilino group, 3,4-di (3-perfluorohexylpropyloxy) anilino group, N-1,3,5-triazin-2-ylamino group), An acylamino group (preferably a formylamino group, a substituted or unsubstituted alkylcarbonylamino group having 1 to 30 carbon atoms, a substituted or unsubstituted arylcarbonylamino group having 6 to 30 carbon atoms, such as a formylamino group, Acetylamino group, pivaloylamino group, lauroylamino group, benzoylamino group, 3,4,5 Tri-n-octyloxyphenylcarbonylamino group), aminocarbonylamino group (preferably a substituted or unsubstituted aminocarbonylamino group having 1 to 30 carbon atoms such as carbamoylamino group, N, N-dimethylaminocarbonylamino group) Group, N, N-diethylaminocarbonylamino group, morpholinocarbonylamino group), alkoxycarbonylamino group (preferably a substituted or unsubstituted alkoxycarbonylamino group having 2 to 30 carbon atoms such as methoxycarbonylamino group, ethoxycarbonylamino group) Group, tert-butoxycarbonylamino group, n-octadecyloxycarbonylamino group, N-methyl-methoxycarbonylamino group),

  Aryloxycarbonylamino group (preferably a substituted or unsubstituted aryloxycarbonylamino group having 7 to 30 carbon atoms such as phenoxycarbonylamino group, p-chlorophenoxycarbonylamino group, mn-octyloxyphenoxycarbonyl) Amino group), sulfamoylamino group (preferably a substituted or unsubstituted sulfamoylamino group having 0 to 30 carbon atoms, such as sulfamoylamino group, N, N-dimethylaminosulfonylamino group, N -N-octylaminosulfonylamino group), alkyl and arylsulfonylamino groups (preferably substituted or unsubstituted alkylsulfonylamino groups having 1 to 30 carbon atoms, substituted or unsubstituted arylsulfonylamino groups having 6 to 30 carbon atoms) For example, methyls Sulfonylamino group, butylsulfonylamino group, phenylsulfonylamino group, 2,3,5-trichlorophenylsulfonylamino group, p-methylphenylsulfonylamino group), mercapto group,

  An alkylthio group (preferably a substituted or unsubstituted alkylthio group having 1 to 30 carbon atoms, such as a methylthio group, an ethylthio group or an n-hexadecylthio group), an arylthio group (preferably a substituted or unsubstituted group having 6 to 30 carbon atoms); An arylthio group, for example, a phenylthio group, a p-chlorophenylthio group, an m-methoxyphenylthio group), a heterocyclic thio group (preferably a substituted or unsubstituted heterocyclic thio group having 2 to 30 carbon atoms, Is preferably a heterocyclic moiety described in the above heterocyclic group, for example, 2-benzothiazolylthio, 1-phenyltetrazol-5-ylthio), a sulfamoyl group (preferably substituted or unsubstituted having 0 to 30 carbon atoms) A sulfamoyl group such as N-ethylsulfamoyl group, N- (3-dodecyloxypro Le) sulfamoyl group, N, N- dimethylsulfamoyl group, N- acetyl sulfamoyl group, N- benzoylsulfamoyl group, N- (N'-phenylcarbamoyl) sulfamoyl group), a sulfo group,

  An alkylsulfinyl group and an arylsulfinyl group (preferably a substituted or unsubstituted alkylsulfinyl group having 1 to 30 carbon atoms, a substituted or unsubstituted arylsulfinyl group having 6 to 30 carbon atoms such as a methylsulfinyl group and an ethylsulfinyl group; , Phenylsulfinyl group, p-methylphenylsulfinyl group), alkyl and arylsulfonyl groups (preferably a substituted or unsubstituted alkylsulfonyl group having 1 to 30 carbon atoms, a substituted or unsubstituted arylsulfonyl group having 6 to 30 carbon atoms) Yes, for example, methylsulfonyl group, ethylsulfonyl group, phenylsulfonyl group, p-methylphenylsulfonyl group), acyl group (preferably formyl group, substituted or unsubstituted alkylcarbonyl group having 2 to 30 carbon atoms, carbon number 7 ~ 30 substitutions Or an unsubstituted arylcarbonyl group, for example, acetyl group, pivaloyl group, 2-chloroacetyl group, stearoyl group, benzoyl group, pn-octyloxyphenylcarbonyl group), aryloxycarbonyl group (preferably, A substituted or unsubstituted aryloxycarbonyl group having 7 to 30 carbon atoms such as a phenoxycarbonyl group, o-chlorophenoxycarbonyl group, m-nitrophenoxycarbonyl group, p-tert-butylphenoxycarbonyl group), halogen atom ( For example, chlorine atom, bromine atom, iodine atom),

  An alkoxycarbonyl group (preferably a substituted or unsubstituted alkoxycarbonyl group having 2 to 30 carbon atoms such as methoxycarbonyl group, ethoxycarbonyl group, tert-butoxycarbonyl group, n-octadecyloxycarbonyl group), carbamoyl group (preferably Is a substituted or unsubstituted carbamoyl group having 1 to 30 carbon atoms, such as a carbamoyl group, N-methylcarbamoyl group, N, N-dimethylcarbamoyl group, N, N-di-n-octylcarbamoyl group, N- ( Methylsulfonyl) carbamoyl group), aryl and heterocyclic azo groups (preferably substituted or unsubstituted arylazo groups having 6 to 30 carbon atoms, substituted or unsubstituted heterocyclic azo groups having 3 to 30 carbon atoms (the heterocyclic moiety is The heterocyclic moiety described in the above heterocyclic group is preferable. For example, phenylazo, p-chlorophenylazo, 5-ethylthio-1,3,4-thiadiazol-2-ylazo), an imide group (preferably a substituted or unsubstituted imide group having 2 to 30 carbon atoms, such as N -Succinimide group, N-phthalimide group), phosphino group (preferably a substituted or unsubstituted phosphino group having 2 to 30 carbon atoms, such as dimethylphosphino group, diphenylphosphino group, methylphenoxyphosphino group), phosphinyl A group (preferably a substituted or unsubstituted phosphinyl group having 2 to 30 carbon atoms, such as a phosphinyl group, a dioctyloxyphosphinyl group, a diethoxyphosphinyl group),

  Phosphinyloxy group (preferably a substituted or unsubstituted phosphinyloxy group having 2 to 30 carbon atoms, such as diphenoxyphosphinyloxy group, dioctyloxyphosphinyloxy group), phosphinylamino A group (preferably a substituted or unsubstituted phosphinylamino group having 2 to 30 carbon atoms, such as a dimethoxyphosphinylamino group or a dimethylaminophosphinylamino group), a silyl group (preferably a carbon number of 3 -30 substituted or unsubstituted silyl groups, for example, trimethylsilyl group, tert-butyldimethylsilyl group, phenyldimethylsilyl group).

  Among the above functional groups, those having a hydrogen atom may be substituted with the above groups by removing this. Examples of such a functional group include an alkylcarbonylaminosulfonyl group, an arylcarbonylaminosulfonyl group, an alkylsulfonylaminocarbonyl group, and an arylsulfonylaminocarbonyl group. Specifically, a methylsulfonylaminocarbonyl group, p- Examples include methylphenylsulfonylaminocarbonyl group, acetylaminosulfonyl group, and benzoylaminosulfonyl group.

Examples of R ⁵¹ and R ⁵² include those represented by the following general formula (VI). That is, the general formula (V) includes multimers.
General formula (VI)

In the general formula (VI), Z ⁶¹ represents a q-valent linking group. (Q-1) represents an integer of 2 or more. X ⁶¹ and X ⁶² each represent NRa (Ra represents a hydrogen atom, an alkyl group or an aryl group), O, or S, and the plurality of X ⁶¹ and X ⁶² may be the same or different. R ⁶¹ and R ⁶² each represent a substituent, and the plurality of R ⁶¹ and R ⁶² may be the same or different.

In the general formula (VI), the substituents represented by R ⁶¹ and R ⁶² are synonymous with R ⁵¹ and R ⁵² in the general formula (V), and the preferred ranges are also the same.

More preferably, the general formula (V) is the following general formula (VII).
Formula (VII)

In the general formula (VII), Z ⁷¹ represents a divalent linking group. X ⁷¹ and X ⁷² each represent NRa (Ra represents a hydrogen atom, an alkyl group or an aryl group), O, or S. R ⁷¹ , R ⁷² , R ⁷³ and R ⁷⁴ each represent a substituent.

In the general formula (VII), the divalent linking group represented by Z ⁷¹ is an alkylene group, an alkenylene group, a divalent aromatic group, a divalent heterocyclic residue, —O—, —CO—, — SO -, - SO ₂ - and preferably a divalent connecting group selected from the group consisting of.

In the general formula (VII), the substituents represented by R ⁷¹ , R ⁷² , R ⁷³ and R ⁷⁴ are respectively synonymous with R ⁵¹ and R ⁵² in the general formula (V).

Preferably, R ⁷¹ , R ⁷² , R ⁷³ and R ⁷⁴ are each an optionally substituted alkoxy group, aryloxy group, heterocyclic oxy group, alkylthio group, arylthio group, heterocyclic thio group, amino group An alkylamino group, an arylamino group, or a heterocyclic amino group, and more preferably an alkylamino group which may have a substituent [for example, methylamino group, dimethylamino group, 3-perfluorohexylpropylamino group, 3 -(2,4-di-tert-amylphenoxy) propylamino group, 3- (2-ethylhexyloxy) propylamino group, 3- (2-hexyldecanooxy) propylamino group, 3-octyloxypropylamido group , 3-dodecyloxypropylamino group, 3- (3-perfluorohexylpropyloxy) propyla Group, 3- (3- (6H-perfluorohexyl) propyloxy) propylamino group], arylamino group [for example, anilino group, N-methyl-anilino group, diphenylamino group, 2-methyloxyanilino group, 2- (3-perfluorohexylpropyloxy) anilino group, 2- (2-perfluorobutylethyloxy) anilino group, 2,4-di (2-perfluorohexylethyloxy) anilino group, 2- (6H- Perfluorohexylmethyloxy) anilino group, 3,4-di (3-perfluorohexylpropyloxy) anilino group]. Examples of the substituent which may be included include the examples given for R ⁵¹ and R ⁵² in formula (V).

Even more preferably, the general formula (V) is the following general formula (VIII).
Formula (VIII)

In the general formula (VIII), X ⁸¹ and X ⁸² each represent NRa (Ra represents a hydrogen atom, an alkyl group or an aryl group), O, or S. A ⁸¹ , A ⁸² and A ⁸³ each represent a divalent linking group, and the plurality of A ⁸² may be the same or different. u represents an integer of 0 or more. R ⁸¹ , R ⁸² , R ⁸³ and R ⁸⁴ each represent a substituent.

In the general formula (VIII), the substituents represented by R ⁸¹ , R ⁸² , R ⁸³ and R ⁸⁴ are respectively synonymous with R ⁷¹ , R ⁷² , R ⁷³ and R ⁷⁴ in the general formula (VII). The preferred range is also the same.

In the general formula (VIII), A ⁸¹ , A ⁸² and A ⁸³ are divalent linking groups such as an alkylene group, an alkenylene group, a divalent aromatic group, a divalent heterocyclic residue, —CO—, A divalent linking group selected from the group consisting of —SO—, —SO ₂ — and combinations thereof is preferable. More preferably, it is an alkylene group (a linear or branched substituted or unsubstituted alkylene group, preferably an alkylene group having 1 to 30 carbon atoms, such as —CH ₂ —, — (CH ₂ ) ₂ —, —CH _2. CH (CH ₃ ) —, —CH ₂ C (CH ₃ ) ₂ —, — (CH ₂ ) ₄ —), and more preferably — (CH ₂ ) ₂ —, —CH ₂ CH (CH ₃ ) —. , — (CH ₂ ) ₄ —.

The aforementioned alkylene group, alkenylene group, divalent aromatic group and divalent heterocyclic residue may have a substituent if possible. Examples of such a substituent include the examples given for R ⁵¹ and R ⁵² in formula (V).

  Specific examples of the compound having a 1,3,5-triazine ring group that can be used in the present invention are shown below, but the compound used in the present invention is not limited thereto.

  The addition amount of the compound having a 1,3,5-triazine ring group is preferably 0.01 to 20% by mass relative to the liquid crystal compound (preferably a discotic liquid crystal compound), 0.05 More preferably, it is 10 mass%, It is further more preferable that it is 0.1-5 mass%.

1-5. Cellulose ester The optically anisotropic layer of the optical compensation sheet of the present invention preferably contains a cellulose ester. By using the cellulose ester, the tilt angle of the liquid crystal compound can be changed as in the case of the compound represented by the general formula (I).

  The cellulose ester used in the present invention is not particularly defined as long as it does not depart from the spirit of the present invention, but it is preferable to use a lower fatty acid ester of cellulose. The “lower fatty acid” in the lower fatty acid ester of cellulose means a fatty acid having 6 or less carbon atoms. The number of carbon atoms is preferably 2 to 5, and more preferably 2 to 4. A substituent (eg, hydroxy) may be bonded to the fatty acid. Two or more types of fatty acids may form an ester with cellulose. Examples of lower fatty acid esters of cellulose include cellulose acetate, cellulose propionate, cellulose butyrate, cellulose hydroxypropionate, cellulose acetate propionate, and cellulose acetate butyrate. Cellulose acetate butyrate is particularly preferred. The degree of butyrylation of cellulose acetate butyrate is preferably 30% or more, and more preferably 80% or less. The acetylation degree of cellulose acetate butyrate is preferably 30% or less, and more preferably 1% or more. The addition amount of the cellulose ester is preferably in the range of 0.1 to 10% by mass and preferably in the range of 0.1 to 8% by mass with respect to the liquid crystal compound so as not to inhibit the alignment of the liquid crystal compound. It is more preferable.

1-6. Polymerization initiator In this invention, a polymerization initiator can be employ | adopted as what fixes the oriented liquid crystalline compound, maintaining an orientation state. The immobilization is preferably performed by a polymerization reaction. The polymerization reaction includes a thermal polymerization reaction using a thermal polymerization initiator and a photopolymerization reaction using a photopolymerization initiator. A photopolymerization reaction is preferred.
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) Acridine and phenazine compounds (JP-A-60-105667, U.S. Pat. No. 4,239,850) and oxadiazole compounds (U.S. Pat. No. 4,212,970).
The amount of the photopolymerization initiator used is preferably in the range of 0.01 to 20% by mass, more preferably in the range of 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 in the range of ^{20mJ / cm 2 ~50J / cm 2} , more preferably in the range of 20~5000mJ / cm ^2, more preferably in the range of 100 to 800 mJ / cm ² . In order to accelerate the photopolymerization reaction, light irradiation may be performed under heating conditions.
A protective layer may be provided on the optically anisotropic layer.

1-7. Liquid crystalline composition constituting the optically anisotropic layer The liquid crystalline composition constituting the optically anisotropic layer of the present invention includes the liquid crystalline compound and the compound represented by the general formula (I). The component is not particularly defined, but is preferably a liquid crystal composition containing a liquid crystal compound, a compound represented by formula (I), a fluorine-based polymer and a cellulose ester.
Furthermore, in addition to the above composition, the optically anisotropic layer of the present invention can be used in combination with a plasticizer, a surfactant, a polymerizable monomer, etc., so that the uniformity of the coating film, the strength of the film, and the orientation of the liquid crystal molecules Etc. can be improved. These are preferably compatible with the liquid crystal compound and can change the tilt angle of the liquid crystal compound or do not inhibit the alignment.

  Examples of the polymerizable monomer include radically polymerizable or cationically polymerizable compounds. Preferably, it is a polyfunctional radically polymerizable monomer and is preferably copolymerizable with the polymerizable group-containing liquid crystalline compound. Examples thereof include those described in paragraph numbers [0018] to [0020] in JP-A No. 2002-296423. The amount of the compound added is preferably in the range of 1 to 50% by mass, more preferably in the range of 5 to 30% by mass with respect to the discotic liquid crystalline compound.

  Examples of the surfactant include conventionally known compounds, and fluorine compounds are particularly preferable. Specific examples include compounds described in paragraph numbers [0028] to [0056] in JP-A-2001-330725.

2. Next, the support used for the optical compensation sheet of the present invention will be described in detail.
The support used for the optical compensation sheet of the present invention is preferably a transparent support made of glass or a transparent polymer film.
The support preferably has a light transmittance of 80% or more. Examples of the polymer constituting the polymer film include cellulose esters (eg, cellulose mono-triacylate), norbornene-based polymers, and polymethyl methacrylate. A commercially available polymer (for Norbornene-based polymers, both Arton and Zeonex are trade names)) may be used. In addition, even a conventionally known polymer such as polycarbonate or polysulfone that easily develops birefringence can be improved in birefringence by modifying the molecule as described in International Publication WO00 / 26705. If controlled, it can also be used in the optical film of the present invention.

Among these, cellulose esters are preferable, and lower fatty acid esters of cellulose are more preferable. Lower fatty acid means a fatty acid having 6 or less carbon atoms. In particular, cellulose acylate having 2 to 4 carbon atoms is preferable. Cellulose acetate is particularly preferred. Mixed fatty acid esters such as cellulose acetate propionate and cellulose acetate butyrate may be used.
The viscosity average degree of polymerization (DP) of cellulose acetate is preferably 250 or more, and more preferably 290 or more. Cellulose acetate preferably has a narrow molecular weight distribution of Mw / Mn (Mw is a mass average molecular weight, Mn is a number average molecular weight) by gel permeation chromatography. A specific value of Mw / Mn is preferably 1.0 to 1.7, and more preferably 1.0 to 1.65.

As the polymer film, it is preferable to use cellulose acetate having an acetylation degree of 55.0 to 62.5%. The acetylation degree is more preferably 57.0 to 62.0%.
The degree of acetylation means the amount of bound acetic acid per unit mass of cellulose. The degree of acetylation is determined by measurement and calculation of the degree of acetylation in ASTM: D-817-91 (test method for cellulose acetate and the like).

In cellulose acetate, the hydroxyl groups at the 2-position, 3-position and 6-position of cellulose are not evenly substituted, but the substitution degree at the 6-position tends to be small. In the polymer film used in the present invention, it is preferable that the degree of substitution at the 6-position of cellulose is the same or greater than that at the 2- and 3-positions.
The ratio of the substitution degree at the 6-position to the total substitution degree at the 2-position, the 3-position, and the 6-position is preferably 30 to 40%, more preferably 31 to 40%, and more preferably 32 to 40%. Most preferably it is. The substitution degree at the 6-position is preferably 0.88 or more.
These specific acyl groups and the method for synthesizing cellulose acylate are described in detail on page 9 of the Japan Society for Invention and Innovation (Technical Number 2001-1745, published on March 15, 2001). .

When using a polymer film for an optical compensation sheet, the polymer film preferably has a desired retardation value. In this specification, Re and Rth respectively represent in-plane retardation and retardation in the thickness direction at a wavelength λ.
Re is measured with KOBRA 21ADH (manufactured by Oji Scientific Instruments Co., Ltd.) by making light of wavelength λ nm incident in the normal direction of the film. Rth was measured by making light having a wavelength λ nm incident from a direction inclined + 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). A retardation value and a retardation value measured by making light having a wavelength λ nm incident from a direction inclined −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. The average refractive index values of main optical films are exemplified below: cellulose acylate (1.48), cycloolefin polymer (1.52), polycarbonate (1.59), polymethyl methacrylate (1.49), 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.

In the present specification, the “tilt angle” refers to an angle formed by the normal line between the major axis direction of the molecule of the liquid crystal compound and the interface (alignment film interface or air interface). The angle is preferably 3 ° to 30 °, and the inclination angle on the air interface side is preferably 40 to 80 °. If the tilt angle on the alignment film side is too small, it is preferable to increase the time required for monodomain alignment of the liquid crystal compound, particularly the discotic liquid crystal compound. However, if the tilt angle is too large, the optical compensation is performed. On the contrary, it is not preferable because optical performance preferable as a sheet cannot be obtained. Therefore, from the viewpoint of both shortening of the monodomain formation time and preferable optical performance as the optical compensation sheet, the preferable inclination angle on the alignment film side is 5 ° to 50 °, more preferably 10 ° to 50 °, Particularly preferred is 10 to 30 °. Moreover, the preferable inclination angle on the air interface side is 40 to 80 °, more preferably 50 to 80 °, and particularly preferably 50 to 70 °. The tilt angle on the alignment film side can be controlled in the range of several degrees to several tens of degrees by changing the light irradiation direction of the alignment film, or by adding the aforementioned alignment film tilt angle control agent. As described above, when the optically anisotropic layer is once formed and then disposed between two layers by transfer or the like, the interface of the optically anisotropic layer is not necessarily the alignment film interface and the air interface. In such an embodiment, the tilt angle of the liquid crystal compound on each of the two interface sides of the two interfaces of the optically anisotropic layer and the other interface side is the range of the tilt angle on the alignment film side and the air interface. It is preferable that it is the range of the side inclination angle. In particular, the tilt angle θ1 of the discotic liquid crystal compound at the interface of the alignment layer of the optically anisotropic layer preferably satisfies 10 ° ≦ θ1 ≦ 30 °.
The tilt angle between the two interfaces is the tilt angle on the surface of the optically anisotropic layer on the alignment film side (the angle formed by the physical symmetry axis in the discotic liquid crystalline compound or the like with the interface of the optically anisotropic layer) θ1 and air It is obtained by determining the inclination angle θ2 of the interface side surface. Since it is difficult to directly and accurately measure θ1 and θ2, in this specification, θ1 and θ2 are calculated based on the following two assumptions in order to facilitate calculation. Although this method does not accurately represent the actual orientation state of the present invention, it is effective as a means for expressing the relative relationship of some optical properties of the optical film.
1. The optically anisotropic layer is assumed to be a multilayer body composed of layers containing a discotic liquid crystalline compound or the like. Further, the minimum unit layer (assuming that the tilt angle of the discotic liquid crystalline compound is uniform in the layer) is assumed to be optically uniaxial.
2. It is assumed that the inclination angle of each layer changes monotonically with a linear function along the thickness direction of the optically anisotropic layer.
The specific calculation method is as follows.
(1) The angle of incidence of the measurement light on the optically anisotropic layer is changed within a plane in which the inclination angle in each layer changes monotonically with a linear function along the thickness direction of the optically anisotropic layer. The retardation value is measured at the measurement angle. In order to simplify measurement and calculation, it is preferable to measure the retardation value at three measurement angles of −40 °, 0 °, and + 40 °, with the normal direction to the optically anisotropic layer being 0 °. Such measurements include KOBRA-21ADH and KOBRA-WR (manufactured by Oji Scientific Instruments), transmission ellipsometer AEP-100 (manufactured by Shimadzu Corporation), M150 and M520 (manufactured by JASCO Corporation) ), ABR10A (manufactured by UNIOPT Co., Ltd.).
(2) In the above model, the refractive index of ordinary light of each layer is no, the refractive index of extraordinary light is ne (ne is the same value in all layers, and no is the same), and the thickness of the entire multilayer body is d And Furthermore, based on the assumption that the tilt direction of each layer and the uniaxial optical axis direction of that layer coincide with each other, the calculation of the angular dependence of the retardation value of the optically anisotropic layer agrees with the measured value. Fitting is performed using the tilt angle θ1 on one surface of the isotropic layer and the tilt angle θ2 of the other surface as variables, and θ1 and θ2 are calculated.
Here, for no and ne, known values such as literature values and catalog values can be used. If the value is unknown, it can also be measured using an Abbe refractometer. The thickness of the optically anisotropic layer can be measured by an optical interference film thickness meter, a cross-sectional photograph of a scanning electron microscope, or the like. The measurement wavelength is 632.8 nm.

Although the polymer film retardation value varies depending on the liquid crystal cell in which the optical compensation sheet is used and the method of use thereof, the Re retardation value is preferably 0 to 200 nm, and the Rth retardation value is preferably 70 to 400 nm.
Further, when two optically anisotropic layers are used in the liquid crystal display device, the Rth retardation value of the polymer film is preferably in the range of 70 to 250 nm. When one optically anisotropic layer is used in the liquid crystal display device, the Rth retardation value of the substrate is preferably in the range of 150 to 400 nm.

  In addition, it is preferable that the birefringence ((DELTA) n: nx-ny) of a base film exists in the range of 0.00028-0.020. The birefringence {(nx + ny) / 2−nz} in the thickness direction of the cellulose acetate film is preferably in the range of 0.001 to 0.04.

  In order to adjust the retardation of the polymer film, a method of applying an external force such as stretching is common, but a retardation increasing agent for adjusting optical anisotropy is optionally added. In order to adjust the retardation of the cellulose acylate film, an aromatic compound having at least two aromatic rings is preferably used as a retardation increasing agent. The aromatic compound is preferably used in the range of 0.01 to 20 parts by mass with respect to 100 parts by mass of cellulose acylate. Two or more aromatic compounds may be used in combination. The aromatic ring of the aromatic compound includes an aromatic hetero ring in addition to the aromatic hydrocarbon ring. Examples thereof include compounds described in European Patent 0911656A2, JP-A Nos. 2000-1111914 and 2000-275434.

Furthermore, the hygroscopic expansion coefficient of the cellulose acetate film used in the optical compensation sheet of the present invention is preferably 30 × 10 ⁻⁵ /% RH or less. The hygroscopic expansion coefficient is more preferably 15 × 10 ⁻⁵ /% RH or less, and further preferably 10 × 10 ⁻⁵ /% RH or less. Further, the hygroscopic expansion coefficient tends to be smaller, but a value of 1.0 × 10 ⁻⁵ /% RH or more is more preferable.
The hygroscopic expansion coefficient indicates the amount of change in the length of the sample when the relative humidity is changed at a constant temperature.
By adjusting the hygroscopic expansion coefficient, it is possible to prevent a frame-like transmittance increase (light leakage due to distortion) while maintaining the optical compensation function of the optical compensation sheet.
The method for measuring the hygroscopic expansion coefficient is shown below. A sample having a width of 5 mm and a length of 20 mm was cut out from the produced polymer film, and one end was fixed and suspended in an atmosphere of 25 ° C. and 20% RH (R0). A weight of 0.5 g was hung from the other end and left for 10 minutes to measure the length (L0). Next, the temperature was kept at 25 ° C., the humidity was 80% RH (R1), and the length (L1) was measured. The hygroscopic expansion coefficient was calculated by the following equation. The measurement was performed 10 samples for the same sample, and the average value was adopted.
Hygroscopic expansion coefficient [/% RH] = {(L1-L0) / L0} / (R1-R0)

  In order to reduce the dimensional change due to moisture absorption of the polymer film, it is preferable to add a compound having a hydrophobic group or fine particles. As the compound having a hydrophobic group, a material corresponding to a plasticizer or a degradation inhibitor having a hydrophobic group such as an aliphatic group or an aromatic group in the molecule is particularly preferably used. It is preferable that the addition amount of these compounds exists in the range of 0.01-10 mass% with respect to the solution (dope) to adjust. Further, the free volume in the polymer film may be reduced. Specifically, it is preferable that the amount of residual solvent at the time of film formation by the solvent casting method described later is small because free deposition becomes small. It is preferable to dry under the condition that the residual solvent amount with respect to the cellulose acetate film is in the range of 0.01 to 1.00% by mass.

  The above-mentioned additives to be added to the polymer film and additives that can be added according to various purposes (for example, an ultraviolet ray inhibitor, a release agent, an antistatic agent, a deterioration preventing agent (eg, an antioxidant, a peroxide decomposing agent, The radical inhibitor, metal deactivator, acid scavenger, amine), infrared absorber and the like may be solid or oily. Moreover, when a film is formed from a multilayer, the kind and addition amount of the additive of each layer may differ. For these details, the materials described in detail on pages 16 to 22 of the technique No. 2001-1745 described above are preferably used. The amount of these additives used is not particularly limited as long as the amount of each material is manifested, but it is preferably used as appropriate in the range of 0.001 to 25% by mass in the entire polymer film composition.

2-1. Production method of polymer film The polymer film is preferably produced by a solvent cast method. In the solvent cast method, a film is produced using a solution (dope) in which a polymer material is dissolved in an organic solvent. The dope is cast on a drum or band and the solvent is evaporated to form a film. The concentration of the dope before casting is preferably adjusted so that the solid content is 18 to 35%. The surface of the drum or band is preferably finished in a mirror state.
The dope is preferably cast on a drum or band having a surface temperature of 10 ° C. or less. After casting, it is preferable to dry it by applying air for 2 seconds or more. The obtained film can be peeled off from the drum or band and further dried with high-temperature air whose temperature is successively changed from 100 to 160 ° C. to evaporate the residual solvent. The above method is described in Japanese Patent Publication No. 5-17844. According to this method, it is possible to shorten the time from casting to stripping. In order to carry out this method, it is necessary for the dope to gel at the surface temperature of the drum or band during casting.

In the casting step, one type of cellulose acylate solution may be cast as a single layer, or two or more types of cellulose acylate solutions may be cast simultaneously and / or sequentially.
As a method of co-casting a plurality of cellulose acylate solutions of two or more layers as described above, for example, a solution containing cellulose acylate from a plurality of casting openings provided at intervals in the traveling direction of the support. A method of casting and laminating each (for example, a method described in JP-A-11-198285) A method of casting a cellulose acylate solution from two casting ports (a method described in JP-A-6-134933) A method of wrapping a flow of a high-viscosity cellulose acylate solution with a low-viscosity cellulose acylate solution and simultaneously extruding the high- and low-viscosity cellulose acylate solution (method described in JP-A-56-162617), etc. Can be mentioned. The present invention is not limited to these.
The manufacturing process of these solvent casting methods is described in detail on pages 22 to 30 of the aforementioned technical number 2001-1745, and includes dissolution, casting (including co-casting), metal support, drying, peeling. Categorized as stretching, etc.

  The thickness of the film of the present invention is preferably 15 to 120 μm, more preferably 30 to 80 μm.

2-2. Surface treatment of polymer film The polymer film is preferably subjected to a surface treatment. Surface treatment includes corona discharge treatment, glow discharge treatment, flame treatment, acid treatment, alkali treatment and ultraviolet irradiation treatment. Details of these are described in detail on pages 30 to 32 of the above-mentioned public technical number 2001-1745. Among these, an alkali saponification treatment is particularly preferable, and it is extremely effective as a surface treatment of a cellulose acylate film.
The alkali saponification treatment may be either immersion in a saponification solution or application of a saponification solution, but a coating method is preferred. Examples of the coating method include a dip coating method, a curtain coating method, an extrusion coating method, a bar coating method, and an E-type coating method. Examples of the alkali saponification treatment liquid include potassium hydroxide solution and sodium hydroxide solution, and the prescribed concentration of hydroxide ions is preferably in the range of 0.1 to 3.0N. Furthermore, as an alkali treatment liquid, a solvent (eg, isopropyl alcohol, n-butanol, methanol, ethanol, etc.) having good wettability to the film, a surfactant, a wetting agent (eg, diols, glycerin, etc.) is contained. Thus, the wettability of the saponification solution to the support, the aging stability of the saponification solution, and the like are improved. Specifically, description of the content is mentioned in Unexamined-Japanese-Patent No. 2002-82226 and international publication WO02 / 46809, for example.

  As means for performing in addition to or in place of the above-mentioned surface treatment method, an undercoat layer (described in JP-A-7-333433) or a resin layer such as gelatin containing both a hydrophobic group and a hydrophilic group A single layer method in which only one layer is applied, a layer (hereinafter abbreviated as the undercoat first layer) is provided as a first layer, which adheres well to a polymer film, and a gelatin, etc., which adheres well to an alignment film as a second layer thereon The content of what is called a multilayer method (for example, description in Unexamined-Japanese-Patent No. 11-248940) which apply | coats a hydrophilic resin layer (henceforth an undercoat 2nd layer) is mentioned.

3. Alignment film In the optical compensation sheet of the present invention, the optically anisotropic layer is formed by applying the composition to the surface of the alignment film. In particular, it is preferable to provide an alignment film on the polymer substrate surface-treated as described above, and to provide an optically anisotropic layer thereon. Here, “application” means that the liquid crystalline composition is almost uniformly present on the surface of the alignment film, such as applying a liquid crystalline composition to the surface of the alignment film.
The alignment film has a function of defining the alignment direction of the liquid crystalline compound. Therefore, if the alignment state is fixed after the alignment of the liquid crystalline compound, the alignment film plays the role, and thus is not necessarily essential as the final form of the optical compensation sheet. That is, it is possible to produce an optical compensation sheet that requires only the optically anisotropic layer on the alignment film in which the alignment state is fixed.

  The alignment film is not particularly limited except for adjusting the pH of the alignment film composition described later, but after applying (for example, applying) a composition containing a polymer and a crosslinking agent on a support, drying by heating (crosslinking). And preferably formed by rubbing treatment.

In the production of the optical compensation sheet of the present invention, the pH of the alignment film composition of the alignment film is adjusted to 6.0 or more. The pH of the alignment film composition is preferably 6.0 to 7.5, more preferably 6.0 to 7.0, and most preferably 6.0 to 6.5.
In adjusting the alignment film composition pH, any of inorganic bases, organic bases, inorganic acids, and organic acids can be used. As the base, it is more preferable to use an inorganic base such as KOH or NaOH.

In principle, the polymer used for the alignment film has a molecular structure having a function of aligning the liquid crystal compound. In the present invention, in addition to the function of aligning the liquid crystalline compound, the crosslinking having the function of binding a side chain having a crosslinkable functional group (eg, double bond) to the main chain or aligning the liquid crystalline compound. It is preferable to introduce a functional functional group into the side chain.
As the polymer used for the alignment film, either a polymer that can be crosslinked by itself or a polymer that is crosslinked by a crosslinking agent can be used, and a plurality of combinations thereof can be used.

  Examples of the polymer include, for example, methacrylate copolymers, styrene copolymers, polyolefins, polyvinyl alcohols and modified polyvinyl alcohols described in paragraph No. [0022] of JP-A-8-338913, poly (N- Methylolacrylamide), polyester, polyimide, vinyl acetate copolymer, carboxymethylcellulose, polycarbonate and the like. Silane coupling agents can be used as the polymer. Water-soluble polymers (eg, poly (N-methylolacrylamide), carboxymethylcellulose, gelatin, polyvinyl alcohol, modified polyvinyl alcohol) are preferred, gelatin, polyvinyl alcohol and modified polyvinyl alcohol are more preferred, and polyvinyl alcohol and modified polyvinyl alcohol are most preferred. . It is particularly preferable to use two types of polyvinyl alcohol or modified polyvinyl alcohol having different degrees of polymerization.

  The saponification degree of polyvinyl alcohol is preferably 70 to 100%, more preferably 80 to 100%. It is preferable that the polymerization degree of polyvinyl alcohol is 100-5000.

The side chain having the function of aligning the liquid crystal compound generally has a hydrophobic group as a functional group. The specific type of functional group is determined according to the type of liquid crystal compound and the required alignment state.
For example, the modifying group of the modified polyvinyl alcohol can be introduced by copolymerization modification, chain transfer modification or block polymerization modification. Examples of modifying groups include hydrophilic groups (carboxylic acid groups, sulfonic acid groups, phosphonic acid groups, amino groups, ammonium groups, amide groups, thiol groups, etc.), hydrocarbon groups having 10 to 100 carbon atoms, fluorine atoms Examples include substituted hydrocarbon groups, thioether groups, polymerizable groups (unsaturated polymerizable groups, epoxy groups, azirinidyl groups, etc.), alkoxysilyl groups (trialkoxy groups, dialkoxy groups, monoalkoxy groups), and the like. As specific examples of these modified polyvinyl alcohol compounds, for example, paragraph numbers [0022] to [0145] in JP-A No. 2000-155216 and paragraph numbers [0018] to [0018] in JP-A No. 2002-62426 are described. [0022] and the like.

When the side chain having a crosslinkable functional group is bonded to the main chain of the alignment film polymer or the crosslinkable functional group is introduced into the side chain having the function of aligning the liquid crystal compound, the alignment film polymer and the optically anisotropic film The polyfunctional monomer contained in the conductive layer can be copolymerized. As a result, not only between the polyfunctional monomer and the polyfunctional monomer, but also between the alignment film polymer and the alignment film polymer and between the polyfunctional monomer and the alignment film polymer is firmly bonded by a covalent bond. Therefore, the strength of the optical compensation sheet can be remarkably improved by introducing the crosslinkable functional group into the alignment film polymer.
The crosslinkable functional group of the alignment film polymer preferably contains a polymerizable group in the same manner as the polyfunctional monomer. Specific examples include those described in paragraphs [0080] to [0100] in JP-A-2000-155216.

Apart from the crosslinkable functional group, the alignment film polymer can also be crosslinked using a crosslinking agent.
Examples of the crosslinking agent include aldehydes, N-methylol compounds, dioxane derivatives, compounds that act by activating carboxyl groups, active vinyl compounds, active halogen compounds, isoxazole, and dialdehyde starch. Two or more kinds of crosslinking agents may be used in combination. Specific examples include compounds described in paragraphs [0023] to [0024] in JP-A No. 2002-62426. Aldehydes having high reaction activity, particularly glutaraldehyde are preferred.

  0.1-20 mass% is preferable with respect to a polymer, and, as for the addition amount of a crosslinking agent, 0.5-15 mass% is more preferable. The amount of the unreacted crosslinking agent remaining in the alignment film is preferably 1.0% by mass or less, and more preferably 0.5% by mass or less. By adjusting in this way, even if the alignment film is used for a long time in a liquid crystal display device or left in a high-temperature and high-humidity atmosphere for a long time, sufficient durability without occurrence of reticulation can be obtained.

  As described above, the crosslinking reaction may be performed at an arbitrary time after coating on the support. When a water-soluble polymer such as polyvinyl alcohol is used as the alignment film forming material, the alignment film composition is preferably a mixed solvent of an organic solvent (eg, methanol) having defoaming action and water. The ratio of water: methanol is preferably 0: 100 to 99: 1, and more preferably 0: 100 to 91: 9. Thereby, generation | occurrence | production of a bubble is suppressed and the defect of the layer surface of an alignment film and also an optically anisotropic layer reduces remarkably.

  The alignment film is preferably applied by spin coating, dip coating, curtain coating, extrusion coating, rod coating, or roll coating. A rod coating method is particularly preferable. The film thickness after drying is preferably 0.1 to 10 μm. Heat drying can be preferably performed at 20 to 110 ° C. In order to form sufficient crosslinking, the temperature is more preferably 60 ° C to 100 ° C, and particularly preferably 80 ° C to 100 ° C. The drying time can be preferably 1 minute to 36 hours, more preferably 1 minute to 30 minutes.

  The alignment film is provided on the support or on the undercoat layer. The alignment film can be obtained by rubbing the surface after crosslinking the polymer layer as described above.

  For the rubbing treatment, a treatment method widely adopted as a liquid crystal alignment treatment process of LCD can be applied. That is, a method of obtaining the orientation by rubbing the surface of the orientation film in a certain direction using paper, gauze, felt, rubber, nylon, polyester fiber or the like can be used. Generally, it is carried out by rubbing several times using a cloth or the like in which fibers having a uniform length and thickness are planted on average.

  Next, the alignment film is functioned to align the liquid crystalline compound of the optically anisotropic layer provided on the alignment film. Thereafter, as necessary, the alignment film polymer and the polyfunctional monomer contained in the optically anisotropic layer are reacted, or the alignment film polymer is crosslinked using a crosslinking agent.

  The thickness of the alignment film is preferably in the range of 0.1 to 10 μm.

4). Coating of Optically Anisotropic Layer on Support The optically anisotropic layer comprises a liquid crystalline compound, a liquid crystal composition containing the compound represented by the general formula (I) and other optional components, an alignment film After being applied (for example, coated), it is formed by bringing it into a desired orientation state (preferably a hybrid orientation).

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, benzene, hexane), alkyl halides (eg, , Chloroform, dichloromethane, tetrachloroethane), esters (eg, methyl acetate, butyl acetate), ketones (eg, acetone, methyl ethyl ketone), ethers (eg, tetrahydrofuran, 1,2-dimethoxyethane). Alkyl halides and ketones are preferred. Two or more organic solvents may be used in combination.
Application (application) of the liquid crystalline composition can be performed by a known method (eg, wire bar coating method, extrusion coating method, direct gravure coating method, reverse gravure coating method, die coating method).
The thickness of the optically anisotropic layer is preferably 0.1 to 20 μm, more preferably 0.5 to 15 μm, and most preferably 1 to 10 μm.

5. Manufacturing method of optically anisotropic layer The manufacturing method of an optically anisotropic layer of the present invention is a manufacturing method of an optically anisotropic layer formed by fixing a liquid crystalline compound in a hybrid alignment state, and the liquid crystalline compound is A first alignment step of horizontally aligning in the presence of the compound represented by the general formula (I) and optionally other additives, a second alignment step of hybrid aligning the horizontally aligned liquid crystalline compound, And an immobilization step of fixing the hybrid aligned liquid crystalline compound in the alignment state. According to the production method of the present invention, it is possible to quickly provide a hybrid alignment optically anisotropic layer with few defects such as schlieren defects by horizontally aligning a liquid crystalline compound and then transferring to a hybrid alignment. it can.

  In the first and / or second alignment step, the liquid crystal compound is subjected to horizontal alignment and / or hybrid alignment by supplying at least one of an electric field, a magnetic field, radiation and heat to the liquid crystal compound. it can. For example, in the first and second alignment steps, the amount of energy supplied from the outside is changed (for example, when the alignment is performed by heating, the heating temperature is changed), or the type of energy supplied is changed. Thus, the alignment state of the liquid crystalline compound can be adjusted. From the viewpoint of production suitability, in the first and second alignment steps, it is preferable to change from the horizontal alignment to the hybrid alignment by changing the heating temperature of the liquid crystalline compound.

  In the present invention, as described above, the liquid crystalline compound can be aligned in a desired alignment state by supplying energy from the outside, but by forming an optically anisotropic layer on the alignment film, or by liquid crystal The desired alignment state can also be achieved by adding a compound capable of controlling the alignment state of the organic compound (such as the compound represented by the general formula (I)) to the optically anisotropic layer.

  The following method can be mentioned as a preferable aspect of the manufacturing method of the optically anisotropic layer of this invention.

A first alignment step of horizontally aligning the liquid crystalline compound at a temperature T ₁ ° C in the presence of the compound represented by the general formula (I) and optionally other additives, and after the first alignment step And an optical anisotropic process including a second alignment step of hybrid-aligning the liquid crystalline compound at a temperature of T ₂ ° C. (where T ₁ <T ₂ ) and an immobilizing step of fixing the hybrid-aligned liquid crystalline compound in the alignment state. It is a manufacturing method of an adhesive layer.

In the first alignment step, for example, a solution in which a discotic liquid crystalline compound, the compound represented by the general formula (I) and a compound necessary for forming an optically anisotropic layer are appropriately dissolved in a solvent is formed on the alignment film. Apply to, then dry. Then heated to a discotic nematic phase-forming temperature, further heated to a temperature (T ₁ ° C.) to take a horizontal alignment state in the liquid crystal phase (the first orientation step). At a temperature T ₁ ° C., the discotic liquid crystalline compound is in a horizontal alignment state. Thereafter, the temperature is further raised to a high temperature region (T ₂ ° C) in the temperature range exhibiting the liquid crystal phase state, and the state is shifted to the hybrid alignment state (second alignment step). Finally, it is polymerized by UV light irradiation or the like to fix the alignment state (fixing step). According to this manufacturing method, an optically anisotropic layer formed by hybrid alignment of discotic liquid crystalline compounds can be rapidly manufactured while suppressing the occurrence of schlieren defects.

In the production method, temperature control in the alignment process of the liquid crystal compound is important. The temperature (T ₁ ° C.) exhibiting a horizontal alignment state, preferably 50 to 200 ° C., more preferably from 70 to 200 ° C., particularly preferably 70 to 120 ° C..

The temperature that exhibits the horizontal alignment state (T ₁ ° C) is lower than the temperature that exhibits the hybrid alignment state (T ₂ ° C). The temperature difference (T ₂ −T ₁ ) is preferably 10 ° C. or more, and more preferably 20 ° C. or more.
T ₁ and T ₂ ° C. are temperatures measured as the film surface temperature of the optically anisotropic layer.

The temperature at which the liquid crystal compound exhibits a horizontal alignment state can be arbitrarily controlled by the type and amount of the liquid crystal compound, the compound represented by the general formula (I), and other optional additives, and accordingly T ₁ ° C and T ₂ ° C can be set. Further, the time for maintaining each temperature at T ₁ ° C and T ₂ ° C and the time for changing from T ₁ ° C to T ₂ ° C can be appropriately set according to the type of the liquid crystalline compound.

6). Polarizing Film The optical compensation sheet of the present invention exhibits its functions remarkably by being bonded to the polarizing film or used as a protective film for the polarizing film.

  The optically anisotropic layer (when providing a plurality of optically anisotropic layers, the first optically anisotropic layer closest to the polarizing film) is preferably formed of a liquid crystalline compound on the polarizing film via an alignment film. . Specifically, the optically anisotropic layer is formed by applying the liquid crystalline composition as described above to the surface of the polarizing film. As a result, without using a polymer film between the polarizing film and the optically anisotropic layer, a thin polarizing plate having a small stress (strain × cross-sectional area × elastic modulus) associated with the dimensional change of the polarizing film is produced. . When the polarizing plate according to the present invention is attached to a large liquid crystal display device, an image with high display quality is displayed without causing problems such as light leakage.

The polarizing film is preferably a coating type polarizing film represented by Optiva Inc., or a polarizing film made of a binder and iodine or a dichroic dye.
Iodine and dichroic dye in the polarizing film exhibit deflection performance by being oriented in the binder. It is preferable that the iodine and the dichroic dye are aligned along the binder molecule, or the dichroic dye is aligned in one direction by self-assembly such as liquid crystal.
Currently, commercially available polarizers are made by immersing a stretched polymer in a solution of iodine or dichroic dye in a bath and allowing iodine or dichroic dye to penetrate into the binder. Is common.
The commercially available polarizing film has iodine or dichroic dye distributed about 4 μm (about 8 μm on both sides) from the polymer surface, and a thickness of at least 10 μm is necessary to obtain sufficient polarization performance. The penetrability can be controlled by the solution concentration of iodine or dichroic dye, the temperature of the bath, and the immersion time.
As described above, the lower limit of the binder thickness is preferably 10 μm. The upper limit of the thickness is preferably as thin as possible from the viewpoint of light leakage of the liquid crystal display device. It is preferably not more than a commercially available polarizing plate (about 30 μm), preferably 25 μm or less, and more preferably 20 μm or less. When the thickness is 20 μm or less, the light leakage phenomenon is not observed on a 17-inch liquid crystal display device.

The binder of the polarizing film may be cross-linked.
As the crosslinked binder, a polymer that can be crosslinked per se can be used. A polarizing film can be formed by reacting a polymer having a functional group or a binder obtained by introducing a functional group into a polymer between the binders by light, heat, or pH change.
Moreover, you may introduce | transduce a crosslinked structure into a polymer with a crosslinking agent.
Crosslinking is generally carried out by applying a coating solution containing a polymer or a mixture of a polymer and a crosslinking agent on a support and then heating. Since it is only necessary to ensure durability at the stage of the final product, the crosslinking treatment may be performed at any stage until the final polarizing plate is obtained.

As the binder for the polarizing film, either a polymer that can be crosslinked by itself or a polymer that is crosslinked by a crosslinking agent can be used. Examples of the polymer include the same polymers as those described in the alignment film. Most preferred are polyvinyl alcohol and modified polyvinyl alcohol. The modified polyvinyl alcohol is described in JP-A-8-338913, JP-A-9-152509 and JP-A-9-316127.
Two or more kinds of polyvinyl alcohol and modified polyvinyl alcohol may be used in combination.

The addition amount of the crosslinking agent in the binder is preferably 0.1 to 20% by mass with respect to the binder. The orientation of the polarizing element and the moisture and heat resistance of the polarizing film are improved. The alignment film contains a certain amount of a crosslinking agent that has not reacted even after the crosslinking reaction has been completed. However, the amount of the remaining crosslinking agent is preferably 1.0% by mass or less and more preferably 0.5% by mass or less in the alignment film. In this way, even if the polarizing film is incorporated in a liquid crystal display device and used for a long time or left in a high temperature and high humidity atmosphere for a long time, the degree of polarization does not decrease.
The crosslinking agent is described in US Reissue Patent 23297. Boron compounds (eg, boric acid, borax) can also be used as a crosslinking agent.

As the dichroic dye, an azo dye, stilbene dye, pyrazolone dye, triphenylmethane dye, quinoline dye, oxazine dye, thiazine dye or anthraquinone dye is used. The dichroic dye is preferably water-soluble. The dichroic dye preferably has a hydrophilic substituent (eg, sulfo group, amino group, hydroxyl group).
Examples of the dichroic dye include compounds described in, for example, the Japan Society for Invention and Innovation, Japanese Patent No. 2001-1745, page 58 (issued on March 15, 2001).

  In order to increase the contrast ratio of the liquid crystal display device, the transmittance of the polarizing plate is preferably higher and the degree of polarization is preferably higher. The transmittance of the polarizing plate is preferably in the range of 30 to 50%, more preferably in the range of 35 to 50%, and most preferably in the range of 40 to 50% in light having a wavelength of 550 nm. . The degree of polarization is preferably in the range of 90 to 100%, more preferably in the range of 95 to 100%, and most preferably in the range of 99 to 100% in light having a wavelength of 550 nm.

  It is also possible to arrange the polarizing film and the optically anisotropic layer, or the polarizing film and the alignment film via an adhesive. As the adhesive, a polyvinyl alcohol resin (including a modified polyvinyl alcohol with an acetoacetyl group, a sulfonic acid group, a carboxyl group, or an oxyalkylene group) or an aqueous boron compound solution can be used. A polyvinyl alcohol resin is preferred. The thickness of the adhesive layer is preferably in the range of 0.01 to 10 μm after drying, and particularly preferably in the range of 0.05 to 5 μm.

6-1. Manufacture of Polarizing Film From the viewpoint of yield, the polarizing film is stretched at an angle of 10 to 80 degrees with respect to the longitudinal direction (MD direction) of the polarizing film (stretching method) or rubbed (rubbing method). Later, it is preferable to dye with iodine or a dichroic dye. The tilt angle is preferably stretched so as to match the angle formed between the transmission axis of the two polarizing plates bonded to both sides of the liquid crystal cell constituting the LCD and the vertical or horizontal direction of the liquid crystal cell.
A normal inclination angle is 45 °. Recently, however, devices that are not necessarily 45 ° have been developed for transmissive, reflective, and transflective LCDs, and it is preferable that the stretching direction can be arbitrarily adjusted in accordance with the design of the LCD.

In the stretching method, the stretching ratio is preferably 2.5 to 30.0 times, and more preferably 3.0 to 10.0 times. Stretching can be performed by dry stretching in air. Moreover, you may implement wet extending | stretching in the state immersed in water. The stretch ratio of dry stretching is preferably 2.5 to 5.0 times, and the stretch ratio of wet stretching is preferably 3.0 to 10.0 times. The stretching step may be performed in several steps including oblique stretching. By dividing into several times, it is possible to stretch more uniformly even at high magnification. Before the oblique stretching, a slight stretching (a degree to prevent shrinkage in the width direction) may be performed horizontally or vertically.
Stretching can be performed by performing tenter stretching in biaxial stretching in different steps. The biaxial stretching is the same as the stretching method performed in normal film formation. In biaxial stretching, stretching is performed at different speeds on the left and right, so that the thickness of the binder film before stretching needs to be different on the left and right. In casting film formation, the flow rate of the binder solution can be differentiated between the left and right sides by tapering the die.
As described above, a binder film that is obliquely stretched by 10 to 80 degrees with respect to the MD direction of the polarizing film is produced.

In the rubbing method, a rubbing treatment method widely adopted as a liquid crystal alignment treatment process of LCD can be applied. That is, the orientation is obtained by rubbing the surface of the film in a certain direction using paper, gauze, felt, rubber, nylon, or polyester fiber. In general, it is carried out by rubbing several times using a cloth in which fibers having a uniform length and thickness are planted on average.
It is preferable to carry out using a rubbing roll in which the roundness, cylindricity, and deflection (eccentricity) of the roll itself are 30 μm or less. The film wrap angle on the rubbing roll is preferably 0.1 to 90 °. However, as described in JP-A-8-160430, a stable rubbing treatment can be obtained by winding 360 ° or more.
When rubbing a long film, the film is preferably transported at a speed of 1 to 100 m / min in a constant tension state by a transport device. The rubbing roll is preferably rotatable in the horizontal direction with respect to the film traveling direction for setting an arbitrary rubbing angle. It is preferable to select an appropriate rubbing angle in the range of 0 to 60 °. When used in a liquid crystal display device, 40 to 50 ° is preferable, and 45 ° is particularly preferable.

It is preferable to dispose a polymer film (arrangement of optically anisotropic layer / polarizing film / polymer film) on the surface of the polarizing film opposite to the optically anisotropic layer.
The polymer film is preferably provided with an antireflection film having an outermost surface having antifouling properties and scratch resistance. Any conventionally known antireflection film can be used.

7). Liquid crystal display device Hereinafter, a liquid crystal display device using the optical compensation sheet of the present invention will be described.
By using the optical compensation sheet of the present invention, a liquid crystal display device having a wide viewing angle can be provided. TN mode optical compensation sheets for liquid crystal cells are described in JP-A-6-214116, US Pat. No. 5,583,679, US Pat. No. 5,646,703, and German Patent Publication 3911620A1. Further, an optical compensation sheet for liquid crystal cells in IPS mode or FLC mode is described in JP-A-10-54982. Furthermore, OCB mode or HAN mode liquid crystal cell optical compensation sheets are described in US Pat. No. 5,805,253 and International Publication WO 96/37804. Furthermore, an optical compensation sheet for an STN mode liquid crystal cell is described in JP-A-9-26572. A VA mode liquid crystal cell optical compensation sheet is described in Japanese Patent No. 2866372.

  In the present invention, optical compensation sheets for liquid crystal cells of various modes can be prepared with reference to the above-mentioned publications. The optical compensation sheet of the present invention includes TN (Twisted Nematic), IPS (In-Plane Switching), FLC (Ferroelectric Liquid Crystal), OCB (Optically Compensatory Bend), STN (Super Twisted Nematic), VA (Vertically Aligned), and HAN. It can be applied to a liquid crystal display device in combination with a liquid crystal cell driven in various modes such as (Hybrid Aligned Nematic) mode. The optical compensation sheet of the present invention is particularly effective in a TN (Twisted Nematic) mode liquid crystal display device.

  The present invention will be described more specifically with reference to the following examples. The materials, amounts used, ratios, processing details, processing procedures, and the like shown in the following examples can be changed as appropriate 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]
(Production of polymer substrate)
The following composition was put into a mixing tank and stirred while heating to dissolve each component to prepare a cellulose acetate solution.

Cellulose acetate solution composition:
Cellulose acetate (linter) with an acetylation degree of 60.9% 80 parts by mass Cellulose acetate (linter) with an acetylation degree of 60.8% 20 parts by mass Triphenyl phosphate (plasticizer) 7.8 parts by mass Biphenyl diphenyl phosphate (plasticizer) 3.9 parts by mass Methylene chloride (first solvent) 300 parts by mass Methanol (second solvent) 54 parts by mass 1-butanol (third solvent) 11 parts by mass

Into the mixing tank, 16 parts by mass of the following retardation increasing agent, 80 parts by mass of methylene chloride and 20 parts by mass of methanol were added and stirred while heating to prepare a retardation increasing agent solution.
A dope was prepared by mixing 474 parts by mass of the cellulose acetate solution with 25 parts by mass of the retardation increasing agent solution and stirring sufficiently. The addition amount of the retardation increasing agent was 3.5 parts by mass with respect to 100 parts by mass of cellulose acetate.

The obtained dope was cast using a band casting machine. After the film surface temperature on the band reached 40 ° C., it was dried for 1 minute, peeled off, and then the polymer base material (PK-1) having a residual solvent amount of 0.3 mass% with 140 ° C. drying air Manufactured.
The obtained polymer substrate (PK-1) had a width of 1500 mm and a thickness of 65 μm. When the retardation value (Re) at a wavelength of 590 nm was measured using KOBRA 21ADH (manufactured by Oji Scientific Instruments), it was 4 nm. Moreover, it was 78 nm when the retardation value (Rth) in wavelength 590nm was measured.

(Surface treatment of polymer substrate and formation of alignment film)
The polymer substrate (PK-1) was immersed in a 2.0N potassium hydroxide solution (25 ° C.) for 2 minutes, then neutralized with sulfuric acid, washed with pure water and dried. The surface energy was determined by a contact angle method and found to be 63 mN / m.

On the prepared PK-1, an alignment film composition (coating solution) adjusted to pH 6.5 with 1N KOH aqueous solution with the following composition was applied with a # 16 wire bar coater at a coating amount of 28 ml / m ^2. did. Drying was performed with warm air of 60 ° C. for 60 seconds, and further with warm air of 90 ° C. for 150 seconds.

Alignment film composition:
The following modified polyvinyl alcohol 10 parts by weight Water 371 parts by weight Methanol 119 parts by weight Glutaraldehyde (crosslinking agent) 0.5 parts by weight

  Next, the alignment film was rubbed in a direction parallel to the slow axis (measured at a wavelength of 632.8 nm) of the polymer substrate (PK-1).

(Formation of optically anisotropic layer)
On the alignment film,
The following discotic liquid crystal compound 41.01 kg
Ethylene oxide modified trimethylolpropane triacrylate (V # 360, manufactured by Osaka Organic Chemical Co., Ltd.) 4.06 kg
Exemplary compounds of general formula (I): I-47 0.09 kg
Photopolymerization initiator (Irgacure 907, manufactured by Ciba Geigy) 1.35 kg
Sensitizer (Kayacure DETX, manufactured by Nippon Kayaku Co., Ltd.) 0.45kg
Was dissolved in 102 kg of methyl ethyl ketone to obtain a liquid crystalline composition (coating solution), which was applied with a wire bar of # 3.4. This was heated and aged in a constant temperature zone of 120 ° C. for 2 minutes to align the discotic liquid crystalline compound. Next, UV irradiation was performed for 1 minute using a 120 W / cm high-pressure mercury lamp in an atmosphere at 80 ° C. to polymerize the discotic liquid crystalline compound. Then, it stood to cool to room temperature. Thus, an optically anisotropic layer was formed, and an optical compensation sheet (KH-80-1) (an orientation-fixed sheet at 80 ° C.) was produced.
In addition, the liquid crystalline composition used for the production of KH-80-1 was applied to the alignment film with a # 3.4 wire bar. This was heated in a constant temperature zone of 120 ° C. for 2 minutes to align the discotic liquid crystalline compound. Next, UV irradiation was performed for 1 minute using a 120 W / cm high-pressure mercury lamp in a 90 ° C. atmosphere to polymerize the discotic liquid crystalline compound. Then, it stood to cool to room temperature. Thus, an optically anisotropic layer was formed, and an optical compensation sheet (KH-90-1) (an orientation-fixed sheet at 90 ° C.) was produced.
Furthermore, the liquid crystalline composition used for the production of KH-1 was applied to the alignment film with a # 3.4 wire bar. This was heated in a constant temperature zone of 120 ° C. for 2 minutes to align the discotic liquid crystalline compound. Next, UV irradiation was performed for 1 minute using a 120 W / cm high-pressure mercury lamp in an atmosphere of 100 ° C. to polymerize the discotic liquid crystalline compound. Then, it stood to cool to room temperature. Thus, an optically anisotropic layer was formed, and an optical compensation sheet (KH-100-1) (an orientation-fixed sheet at 100 ° C.) was produced.

(Preparation of polarizing plate)
Using a polyvinyl alcohol-based adhesive, KH-80-1 (optical compensation sheet) was attached to one side of the polarizer (HF-1). Moreover, the saponification process was performed to the 80-micrometer-thick triacetylcellulose film (TD-80U: Fuji Photo Film Co., Ltd. product), and it affixed on the other side of the polarizer using the polyvinyl alcohol-type adhesive agent.
The transmission axis of the polarizer and the slow axis of PK-1 were arranged in parallel. The transmission axis of the polarizer and the slow axis of the triacetyl cellulose film were arranged so as to be orthogonal to each other. In this way, a polarizing plate (HB-1) was produced.

[Examples 2 to 6]
Production of the polymer substrate and formation / rubbing treatment of the alignment film were carried out in the same manner as in Example 1.
In the preparation of the liquid crystal composition, as shown in Table 1, the exemplified compound represented by the general formula (I) is changed and / or used as an additive as a fluorine-based polymer (exemplified compound P-67 or P-71). ), A compound having 1,3,5-triazine ring group (Exemplary Compound H-26), or a cellulose ester (CAB551-0.2 manufactured by Eastman Chemical Co.) was added as shown in Table 1.
In the formation of the optically anisotropic layer, Examples 4 to 6 were the same as in Example 1 except that the heating in the constant temperature zone at 120 ° C. was changed from 2 minutes to 1 minute. Produced a polarizing plate.
[Comparative Example 1]
In the formation of the alignment film, an optical compensation sheet and a polarizing plate were produced in the same manner as in Example 5 except that the pH of the alignment film composition was adjusted to 5.0 without changing other compositions.
[Comparative Example 2]
In the preparation of the liquid crystal composition, an optical compensation sheet and further a polarizing plate were produced in the same manner as in Example 2 except that the exemplary compound represented by the general formula (I) was not added.

(Evaluation with TN liquid crystal cell)
A pair of polarizing plates provided in a liquid crystal display device (AQUAS LC20C1S, manufactured by Sharp Corporation) using a TN type liquid crystal cell is peeled off, and the polarizing plate (HB-1) prepared in Example 1 is optically replaced. The compensation sheets (KH-80-1) were attached to the observer side and the backlight side one by one through an adhesive so that the compensation sheet (KH-80-1) was on the liquid crystal cell side. The transmission axis of the polarizing plate on the viewer side and the transmission axis of the polarizing plate on the backlight side were arranged to be in the O mode.
About the produced liquid crystal display device, the viewing angle was measured in eight steps from black display (L1) to white display (L8) using the measuring machine (EZ-Contrast160D, ELDIM company make).
The viewing angles were similarly measured for Examples 2 to 6 and Comparative Examples 1 and 2. The measurement results are shown in Table 2.

(Evaluation of unevenness on LCD panel)
The display panels of the liquid crystal display devices of Examples 1 to 6 and Comparative Examples 1 and 2 were adjusted to the whole halftone, and unevenness was evaluated. The results are shown in Table 2.

(Inclination angle evaluation of liquid crystal compound part)
The inclination angle in the vicinity of the alignment film of the liquid crystalline compound and the inclination angle in the vicinity of the air interface in the optically anisotropic layer of the optical compensation sheet are described in Paragraph No. 0156 using an ellipsometer (APE-100, manufactured by Shimadzu Corporation). It was calculated according to the method. The measurement wavelength was 632.8 nm.

(Retardation evaluation of optical compensation sheet)
With respect to each optical compensation sheet produced by changing the orientation fixing temperature, the retardation was measured using KOBRA 21ADH (manufactured by Oji Scientific Instruments) at different observation angles. The measurement wavelength was 632.8 nm. The results are shown in Table 2.

As can be seen from the result of Comparative Example 1 shown in Table 2 above, when the pH of the alignment film composition is less than 6.0, it is not preferable because there is a large retardation decrease accompanying a temperature decrease. Further, as can be seen from the result of Comparative Example 2, the optically anisotropic layer not containing the compound represented by the general formula (I) has an inclination angle at the air interface of the liquid crystalline compound that is too low. The optical compensation sheet having the optically anisotropic layer is not preferable because the viewing angle of the liquid crystal display device cannot be sufficiently expanded.
In the optical compensation sheet containing the exemplary compound of the present invention in the optically anisotropic layer, the tilt angle at the air interface of the liquid crystalline compound is controlled to the optimum value, which greatly contributes to the expansion of the viewing angle. In particular, when the cellulose ester is contained, the tilt angle at the air interface can be further increased, and the viewing angle expansion of the liquid crystal display device is more excellent. In addition, when the fluorine-based polymer was contained, no unevenness was observed in a lattice shape with an upper field of view of 45 ° or more, which was more excellent when applied to a large liquid crystal display device. Furthermore, when a compound having a 1,3,5-triazine ring group was contained, the orientation rate was high, the heat aging time at 120 ° C. could be shortened, and the production efficiency was more excellent.

Claims (10)

The optically anisotropic layer is composed of at least an optically anisotropic layer, and the optically anisotropic layer has a liquid crystalline compound and the following general formula (I) on an alignment film obtained by applying an alignment film composition having a pH of 6 or more on a support. An optical compensation sheet obtained by applying a liquid crystalline composition containing at least one compound represented by the formula:
Formula (I)
(Rf-Y-) _m Ar (-W) _n
(In general formula (I), Ar represents an (m + n) -valent aromatic heterocycle or aromatic hydrocarbon ring, Y represents a single bond or a divalent linking group, and Rf is substituted with an alkyl group or a fluorine atom. W represents a sulfo group or a carboxyl group, m represents an integer of 1 to 4, and n represents 1 or 2. When m represents an integer of 2 or more, a plurality of Rf and Y may be the same or different.When n is 2, each W may be the same or different.) The optical compensation sheet according to claim 1, wherein the optically anisotropic layer further contains a fluoroaliphatic group-containing polymer. The optical compensation sheet according to claim 1, wherein the optically anisotropic layer further contains a cellulose ester. The optical compensation sheet according to claim 1, wherein the optically anisotropic layer further contains a fluoroaliphatic group-containing polymer and a cellulose ester. The optical compensation sheet according to any one of claims 1 to 4, wherein the optically anisotropic layer further contains a compound having a 1,3,5-triazine ring group. The optical compensation sheet according to claim 1, wherein the liquid crystalline compound is a discotic liquid crystalline compound. The optical compensation sheet according to any one of claims 1 to 6, wherein the optically anisotropic layer is formed of a liquid crystal compound having a hybrid alignment, and the hybrid alignment is fixed. A liquid crystal display device comprising the optical compensation sheet according to claim 1. The optical compensation according to any one of claims 1 to 7, comprising a step of horizontally aligning the liquid crystalline compound, a step of hybrid aligning the liquid crystalline compound, and a step of fixing the liquid crystalline compound in the hybrid alignment state. Sheet manufacturing method. A step of forming an alignment film by applying an alignment film composition having a pH of 6 or more on a support; and at least a liquid crystalline compound and a compound represented by the following general formula (I) on the alignment film: A method for producing an optical compensation sheet according to claim 1, comprising a step of forming an optically anisotropic layer by applying a liquid crystalline composition containing one kind.