JP2006091731A - Optical compensation sheet, method of manufacturing the same and polarization plate and liquid crystal display using the sheet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a new optical compensation sheet having an excellent optical compensation function, and a wide viewing angle enlargement performance when the sheet is applied to an image display. <P>SOLUTION: The optical compensation sheet has a transparent supporting body and an optical anisotropic layer including a liquid crystal compound fixed in a hybrid orientation on the supporting body and nitrogen atoms/carbon atoms is smaller than 0.1 on the surface on the air boundary side of the optical anisotropic layer, and fluorine atoms/carbon atoms is 0.1 or larger. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention belongs to the field of a novel optical compensation sheet, and a polarizing plate and a liquid crystal display device using the same. The present invention also belongs to the technical field of a method for controlling the tilt angle at the air interface of a liquid crystal, particularly a discotic liquid crystalline compound, and a method for producing an 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, it has been proposed to use an optical compensation sheet having an optically anisotropic layer made of a discotic liquid crystalline compound on a transparent support in place of the stretched birefringent film. This optically anisotropic layer is usually formed by applying a discotic liquid crystal composition containing a discotic liquid crystal compound on an alignment film, and heating it at a temperature higher than the alignment temperature to align the discotic liquid crystal compound, It is formed by fixing its orientation 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 a conventional stretched birefringent film.

  On the other hand, since the discotic liquid crystalline compound has various alignment forms, it is necessary to control the alignment of the discotic liquid crystalline compound in the optically anisotropic layer in order to express desired optical characteristics. As a method for controlling the discotic liquid crystalline compound to a horizontal alignment state having an average tilt angle of less than 5 degrees, a cellulose lower fatty acid ester, a fluorine-containing surfactant or a 1,3,5-triazine ring is added to the discotic liquid crystalline compound. A method of adding a compound having the above has been proposed (see, for example, Patent Document 1). In addition, there is a method in which a compound having a fluorine-substituted alkyl group and a hydrophilic group (a sulfo group is bonded to a benzene ring through a linking group) is added to the optically anisotropic layer to control the tilt angle of the discotic liquid crystalline compound. It has been proposed (see, for example, Patent Document 2). Furthermore, a method for controlling the orientation of the liquid crystalline compound by using a hydrophobic excluded volume effect compound in combination with the optically anisotropic layer has been proposed (see, for example, Patent Document 3). However, no mention is made of the effect of the compound that effectively promotes the hybrid alignment of the liquid crystal compound and the method of using the compound.

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 uneven light leakage in response to an increase in size and brightness.
The reason for this unevenness is that the organic film is sufficiently contained in the coating film at the initial stage of drying, and if the organic solvent evaporates at this stage, the temperature distribution, surface This is because a tension distribution is generated and a flow such as so-called Marangoni convection occurs in the coating film surface. The occurrence of such unevenness becomes a serious coating defect. For a drying method and apparatus for drying a long and wide coating film surface formed by coating various liquid compositions on a continuously running web, see E.C. B. Gutoff, E .; D. Cohen's “Coating and Drying Defects” (Wiley-Interscience, John Wiley & Sons, Inc.) supports a non-application surface side with a roll, and blows and blows air from an air nozzle on the application surface side. A non-contact type air floating drying method is described in which the air is blown from the air nozzle on both the surface and the non-coated surface, and the web is floated, that is, the support is dried without contacting a roll or the like. As for this non-contact type drying method, there is a drying method using a string-winding type drying apparatus as disclosed in Patent Document 4 as a method for efficiently using space and drying efficiently.

Usually, in the method of drying by blowing these winds (hereinafter referred to as hot air drying method), the solvent contained in the coating surface is evaporated and dried by blowing the conditioned air on the coating surface. Although this hot air drying method is excellent in drying efficiency, since the wind is applied directly to the coated surface or through a porous plate, a rectifying plate, etc., the coated surface is disturbed by this wind and the thickness of the coated layer becomes non-uniform. Problems such as unevenness or non-uniform evaporation rate of the solvent on the coating surface due to convection, so-called crushed skin (see Non-Patent Document 1), etc., and a uniform coating layer cannot be obtained. was there.
Patent Document 5 shows that a coating film can be produced without causing unevenness of film thickness due to drying by limiting the evaporation rate of the coating solution solvent to 0.3 g / (m ² · sec) or less. Although it is possible to obtain a good surface shape by adjusting the conditions of the wind blowing on the coating film and lowering the evaporation rate, if the coating rate is lowered, a long drying process is required to complete the drying. Therefore, it is not a preferable method for improving productivity.

JP 11-352328 A (pages 9-21) JP 2001-330725 A (page 7-10) JP 2002-20363 A (page 3-21) Japanese Patent Publication No. 60-59250 JP 2004-34002 A Yuji Ozaki, “Coating Engineering”, Asakura Shoten, 1971, pp. 293-294

The present invention controls a tilt angle of a liquid crystal compound that is hybrid-aligned in an optically anisotropic layer, is excellent in optical compensation function, and has a wide viewing angle widening performance when applied to an image display device. It is an object to provide a compensation sheet. In particular, it contributes to the improvement of the viewing angle of liquid crystal display devices such as TN mode, OCB mode, and IPS mode that control the tilt angle on the air interface side and contain the hybrid oriented discotic liquid crystalline compound in the optically anisotropic layer. It is an object to provide an optical compensation sheet. 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 polarizing plate that contributes to widening the viewing angle of a liquid crystal display device, and a liquid crystal display device that has excellent viewing angle characteristics and high display quality.
In addition, the present invention can be applied to a long and wide coating film surface formed by coating an optically anisotropic layer on a continuously running belt-like flexible support (hereinafter sometimes referred to as a transparent support). It is an object of the present invention to provide an optical compensation sheet having high film thickness uniformity by suppressing the occurrence of film thickness unevenness occurring at the time of drying, suppressing the film thickness unevenness occurring during drying, and drying efficiently. To do.

Means for solving the above problems are as follows.
[1] An optical compensation sheet having a transparent support and an optically anisotropic layer containing a liquid crystalline compound fixed in a hybrid orientation on the support, the air interface side of the optically anisotropic layer An optical compensation sheet having a number of nitrogen atoms / carbon atoms of less than 0.1 on the surface and a fluorine atom number / carbon atom number of 0.1 or more.
[2] The optically anisotropic layer is a layer produced by a method comprising a step of horizontally aligning molecules of a liquid crystalline compound and a step of hybrid aligning molecules of the horizontally aligned liquid crystalline compound, At a temperature lower than the heating temperature in the step of hybrid orientation, the number of nitrogen atoms / number of carbon atoms on the air interface side surface of the optically anisotropic layer is 0.001 or more, and the number of fluorine atoms / number of carbon atoms is 0. The optical compensation sheet according to [1], which is 1 or more.
[3] The optical compensation sheet according to claim 1 or 2, wherein the optically anisotropic layer contains at least one compound represented by the following general formula (1):
General formula (1)
(Rf-X-) _m Ar (-W) _n
In formula (1), Ar represents an (m + n) -valent aromatic heterocyclic group or aromatic hydrocarbon ring group, X 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, n represents 1 or 2, and when m represents an integer of 2 or more, a plurality of Rf and X may be the same or different.
[4] The optical compensation sheet according to any one of [1] to [3], wherein the optically anisotropic layer contains at least one compound having a triazine ring group.
[5] The optically anisotropic layer further contains at least one fluoroaliphatic polymer, and the number of fluorine atoms / number of carbon atoms on the air interface side surface of the optically anisotropic layer is 0.5 or more. The optical compensation sheet according to any one of 1] to [4].
[6] The optical compensation sheet according to any one of [1] to [5], wherein the optically anisotropic layer further contains a cellulose ester.
[7] The optical compensation sheet according to any one of [1] to [6], wherein the liquid crystalline compound is a discotic liquid crystalline compound.
[8] The optical compensation sheet according to any one of [1] to [7], wherein the optically anisotropic layer is formed of a liquid crystal compound having a hybrid alignment, and the hybrid alignment is fixed.
[9] A liquid crystal display device having the optical compensation sheet according to any one of [1] to [8].
[10] A method for producing an optical compensation sheet having at least a transparent support, an alignment film on the transparent support, and an optically anisotropic layer on the alignment film,
A composition for forming an optically anisotropic layer containing at least a liquid crystalline compound is applied on the surface of a web that is a transparent support having a surface on which an alignment film is formed. A step of performing drying while preventing turbulence of the wind in the vicinity of the coating surface and maintaining a high concentration of solvent vapor on the coating surface during drying, and horizontally aligning the molecules of the liquid crystalline compound on the surface of the alignment film. A method for producing an optical compensation sheet, comprising a step of aligning and a step of hybrid aligning molecules of the horizontally aligned liquid crystalline compound.
[11] A polarizing plate comprising at least a polarizing film and a transparent protective film provided on one surface of the polarizing film, wherein the transparent protective film is an optical compensation sheet according to any one of [1] to [8].
[12] At least a liquid crystal cell and polarizing plates respectively disposed on both sides of the liquid crystal cell, and at least one of the polarizing plates is a polarizing film and one side of the polarizing film, close to the liquid crystal cell And a transparent protective film provided on the liquid crystal display device, wherein the transparent protective film is an optical compensation sheet according to any one of [1] to [8].

In the present invention, by controlling the number of nitrogen atoms / number of carbon atoms and the number of fluorine atoms / number of carbon atoms on the air interface side surface of the optically anisotropic layer containing a liquid crystal compound fixed in a hybrid alignment state, Provided is 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. It can be considered that the tilt angle of the hybrid alignment, particularly the tilt angle on the air interface side, was controlled as a factor for increasing the viewing angle. And controlling the number of nitrogen atoms / number of carbon atoms and the number of fluorine atoms / number of carbon atoms on the air interface side surface of the optically anisotropic layer at a temperature lower than the heating temperature in the step of substantially hybrid alignment. Thus, an optically anisotropic layer with few defects can be applied in a short time. In addition, a dryer having a casing surrounding the web prevents the turbulence of the wind near the coating surface and performs drying while keeping the solvent vapor on the coating surface side being dried at a high concentration. / (M ² · sec) or more, drying unevenness as seen in conventional hot air drying does not occur. Therefore, even if the evaporation rate is set higher than that of the conventional drying method, film thickness unevenness due to drying does not occur, and therefore it is possible to cope with higher speed manufacturing.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, the present invention will be described in detail.
The present invention is an optical compensation sheet having an optically anisotropic layer containing a liquid crystal compound fixed in a hybrid orientation, wherein the number of nitrogen atoms / number of carbon atoms on the air interface side surface of the optically anisotropic layer is The present invention relates to an optical compensatory sheet having a fluorine atom number / carbon atom number of 0.1 or more. In the present invention, the number of nitrogen atoms / number of carbon atoms (hereinafter sometimes abbreviated as “N / C”) on the air interface side surface of the optically anisotropic layer, and the number of fluorine atoms / number of carbon atoms (hereinafter, “ "F / C" may be abbreviated as the peak intensity ratio of the photoelectron energy between nitrogen atoms and carbon atoms and between fluorine atoms and carbon atoms determined by X-ray photoelectron spectroscopy. N / C on the air interface side surface of the optically anisotropic layer is preferably less than 0.1, and more preferably less than 0.025. Further, F / C is preferably 0.1 or more, more preferably 1.0 or more, and most preferably 1.0 to 4.0. When N / C and F / C are in the above ranges, the tilt angle at the air interface of the molecules of the liquid crystal compound can be increased, and as a result, an optically anisotropic layer having good optical compensation ability is obtained.

The optically anisotropic layer is preferably formed by horizontally aligning the molecules of the liquid crystalline compound and then hybrid-aligning and fixing in that state. The optically anisotropic layer produced through this process is preferable because it has few defects. Case of hybrid alignment of molecules of the liquid crystalline compound at the temperature T ₁ ° C., at low temperature T ₂ ° C. than the temperature T ₁ ℃, F / C of the air interface side surface of the optically anisotropic layer is 0.1 or more It is preferable that it is 1.0, it is more preferable that it is 1.0 or more, and it is most preferable that it is 1.0-4.0. Further, N / C is preferably 0.001 or more, and more preferably 0.025 or more. When F / C and N / C are within the above ranges, an optically anisotropic layer with fewer defects is preferable.

  The X-ray photoelectron spectroscopy in the present invention means that the sample surface (that is, the optically anisotropic layer surface) is irradiated with soft X-rays having a narrow energy width (half-value width of about 1 eV) from the sample to the vacuum due to the photoelectric effect. Measure the photoelectron energy and the number of inner and outer shell electrons of the emitted atoms, and analyze the amount of atoms existing in the vicinity of the surface (several nm depth), the environment around the atoms, and the state of chemical bonding. Is the method. Using X-ray photoelectron spectroscopy, the peak intensity ratio of photoelectron energy between fluorine atoms (or nitrogen atoms) and carbon atoms on the surface is used to determine the existence state of fluorine atoms or nitrogen atoms on the surface of the optically anisotropic layer. I can know.

The F / C (or N / C) ratio in this specification is an X-ray photoelectron spectrometer ESCA-3400 manufactured by Kratos Analytical (measurement condition: Mg anode is used, X-ray output is 12 kV-10 mA, path energy is 75 eV). The measurement and measurement ranges were C 1s; 300 to 275 eV, F1s; 700 to 600 eV, N1s; 410 to 390 eV were measured at 0.1 eV steps and 0.5 or 1 second / step. It is the value which measured the peak intensity of and calculated | required with the following formula. The F / C and N / C ratios can be controlled by appropriately changing the content of the fluorine compound and the content of the nitrogen compound. By containing a fluorine compound and a nitrogen compound, which will be described later, in the optically anisotropic layer, the F / C and N / C ratios can be easily adjusted within the above ranges.
F / C ratio = (F1s peak intensity) / (C1s peak intensity)
N / C ratio = (N1s peak intensity) / (C1s peak intensity)

Next, various materials and manufacturing methods used for producing the optical compensation sheet of the present invention will be described in detail.
[Optically anisotropic layer]
The optical compensation sheet of the present invention has an optically anisotropic layer containing a liquid crystal compound fixed in a hybrid alignment state. The optically anisotropic layer may contain various additives other than the liquid crystalline compound because N / C and F / C on the air interface side surface are in the above range. The additive is contained in the optically anisotropic layer by being contained in a composition for forming an optically anisotropic layer, generally, a liquid crystal compound in a coating solution.

[Compound represented by general formula (1)]
The optically anisotropic layer preferably contains a compound represented by the following general formula (1). The compound represented by the following general formula (1) contributes to increasing the tilt angle at the air interface of the liquid crystal compound.
General formula (1)
(Rf-X-) _m Ar (-W) _n
In formula (1), Ar represents an (m + n) -valent aromatic heterocyclic group or aromatic hydrocarbon ring group, X 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 X may be the same or different.

  More specifically, in the general formula (1), the (m + n) -valent aromatic heterocyclic group represented by Ar is preferably an aromatic heterocyclic group having 1 to 30 carbon atoms, more preferably 1 to 12 carbon atoms. It is the basis of. For example, a residue of an aromatic heterocyclic ring containing at least one hetero atom such as a nitrogen atom, an oxygen atom, a sulfur atom, and more specifically, a furan ring, a pyrrole ring, an imidazole ring, a pyrazole ring, an isoxazole ring , Pyridine ring, pyrimidine ring, 1,3,5-triazine ring, indole ring, indazole ring, quinoline ring and carbazole ring are preferred. The (m + n) -valent aromatic hydrocarbon ring group represented by Ar is preferably a residue of an aromatic hydrocarbon ring having 6 to 30 carbon atoms, more preferably 6 to 20 carbon atoms. Residues are most preferred. Ar is preferably a (m + n) -valent aromatic hydrocarbon ring group.

The (m + n) -valent aromatic heterocyclic group or aromatic hydrocarbon ring group represented by Ar may have a substituent other than —X—Rf and —W, and examples of the substituent Examples include the following.
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 is 2 to 10, for example, methoxycarbonyl group, ethoxycarbonyl group and the like, acyloxy group (preferably having 2 to 20 carbon atoms, more preferably 2 to 16 carbon atoms, particularly preferably 2 to 10 carbon atoms). For example, an acetoxy group, a benzoyloxy group, etc.), an acylamino group (preferably an acylamino group having 2 to 20 carbon atoms, more preferably 2 to 16 carbon atoms, and particularly preferably 2 to 10 carbon atoms). Acetylamino group, benzoylamino group, etc.), alkoxycarbonylamino 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), aryloxycarbonylamino A 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 sulfonyl An amino group (preferably a sulfonylamino group having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, and 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 A sulfamoyl group having a prime number of 0 to 16, 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 it is C1-C20, More preferably, it is C1-C16, Most preferably, it is C1-C12 carbamoyl group, for example, unsubstituted carbamoyl group, methylcarbamoyl group, 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 a substituent other than —X—Rf and —W of Ar, 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 are preferable, and an alkyl group, particularly preferably An alkoxy group, an alkoxycarbonyl group, and an acyloxy group. However, Ar is most preferably not substituted with a substituent other than —X—Rf and —W.

In the formula (1), the divalent linking group represented by X is an alkylene group, an alkenylene group, a divalent aromatic group, a divalent heterocyclic residue, -CO-, -NR ^a- (R ^a Is a divalent linking group selected from the group consisting of an alkyl group having 1 to 5 carbon atoms or a hydrogen atom), —O—, —S—, —SO—, —SO ₂ — and combinations thereof. Is preferred. The divalent linking group is a group obtained by combining at least two divalent linking groups selected from an alkylene group, —CO—, —NR ^a —, —O—, —S—, —SO ₂ — and a group thereof. 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. The alkylene group, alkenylene group and arylene group may be substituted with a group exemplified as the above-described Ar substituent (eg, alkyl group, halogen atom, cyano, alkoxy group, acyloxy group, etc.) if possible. .
X is preferably a divalent linking group, and more preferably a divalent linking group selected from the group consisting of an alkylene group, —O—, —S—, and combinations thereof.

  The alkyl group represented by Rf may have a cyclic structure or a branched structure. It is preferable that it is C1-C20, it is more preferable that it is C4-C20, and it is especially preferable that it is C8-C20.

The alkyl group substituted with a fluorine atom represented by Rf may have a cyclic structure or a branched structure, preferably has 1 to 20 carbon atoms, and has 4 to 16 carbon atoms. It is more preferable, and it is especially preferable that it is C4-C12. The substitution rate of fluorine atoms is preferably such that 50% or more of hydrogen atoms contained in the alkyl group are substituted with fluorine atoms, and more preferably 60% or more are substituted. Rf is preferably terminated with a CF ₃ group or a CF ₂ H group, 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.

  The following general formula (1a) is included in the range of the general formula (1).

一般式（１ａ）において、Ｘ²は単結合又は２価の連結基を表し、Ｒｆ²はフッ素原子で置換されたアルキル基を表し、Ｒは水素原子又はアルコキシ基を表す。

In the general formula (1a), X ² represents a single bond or a divalent linking group, Rf ² represents an alkyl group substituted with a fluorine atom, and R represents a hydrogen atom or an alkoxy group.

In the general formula (1a), X ² and Rf ² are synonymous with X and Rf in the general formula (1), and preferred ranges are also the same. The alkyl group part of the alkoxy group represented by R may have a cyclic structure or a branched structure. The alkoxy group preferably has 1 to 20 carbon atoms, more preferably 4 to 20 carbon atoms, and particularly preferably 8 to 20 carbon atoms. If possible, the alkoxy group represented by R may be substituted with a group exemplified as the substituent for Ar described above. R is particularly preferably an unsubstituted alkoxy group.

  The range of the general formula (1) includes the following general formula (2).

General formula (2)
(Rf ¹ -X ^1- ) ₂ Ar ¹ (-W ¹ ) _n1
In Formula (2), Ar ¹ represents an aromatic heterocycle or an aromatic hydrocarbon ring, X ¹ represents a single bond or a divalent linking group, Rf ¹ represents an alkyl group substituted with a fluorine atom, W ¹ represents a sulfo group or a carboxyl group, and n1 represents 1 or 2.

More specifically, in the general formula (2), Ar ¹ , X ¹ , Rf ¹ , W ¹ , and n1 have the same meanings as Ar, X, Rf, W, and n in the general formula (1). And the preferred range is also the same. In formula (2), two X ¹ and Rf ¹ may be the same or different from each other.

  Among the compounds represented by the general formula (2), a compound represented by the following general formula (2a) is preferable.

一般式（２ａ）において、Ｘ³は単結合又は２価の連結基を表し、Ｒｆ³はフッ素原子で置換されたアルキル基を表す。

In the general formula (2a), X ³ represents a single bond or a divalent linking group, and Rf ³ represents an alkyl group substituted with a fluorine atom.

In the general formula (2a), X ³ and Rf ³ has the same meaning as X ¹ and Rf ¹ in formula (2), and their preferred ranges are also the same.

  Specific examples of the compound represented by the general formula (1) are shown below, but the compound used in the present invention is not limited thereto.

  The compound represented by the general formula (1) can be easily synthesized by combining a general alkylation reaction of a hydroxy group and a sulfonation reaction of an aromatic compound.

  The addition amount of the compound represented by the general formula (1) is preferably 0.01 to 20% by mass, particularly preferably 0.05 to 10% by mass, and 0.05 to 1% by mass of the amount of the liquid crystal compound. % Is most preferred. In this invention, 1 type of the compound represented by the said General formula (1) may be used, and 2 or more types may be used. When using 2 or more types, it is preferable that at least 1 type is a compound represented by the said General formula (2). A combination of at least one compound represented by the general formula (1a) and at least one compound represented by the general formula (2) is preferable, and at least one compound represented by the general formula (1a) is preferable. And a combination of at least one of the compounds represented by the general formula (2a) is more preferable.

[Compound having 1,3,5-triazine ring group]
The optically anisotropic layer preferably contains at least one compound having a 1,3,5-triazine ring group. 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 can be contained in the composition used when forming the optically anisotropic layer. In addition, as a compound which has a 1,3,5-triazine ring group which can be used for this invention, the compound represented by the following general formula (5) or (6) is preferable.

In the general formula (5), L ¹ , L ² and L ³ each independently represents a single bond or a divalent linking group, A ¹ , A ² and A ³ each independently represents an alkylene group, m ₂ , m ₃ and m ₄ represent an integer of 0 or more. R ^10, R ¹¹ and R ¹² are each independently an organic group, when m ₂ is 0, R ¹⁰ is an alkyl group, when m ₃ is 0, R ¹¹ is an alkyl group, m ₄ is When 0, R ¹² is an alkyl group.

In the general formula (6), X ⁴ and Y ⁴ each independently represent NR ^a (R ^a represents a hydrogen atom or an alkyl group), O or S, and Z ⁴ represents a divalent linking group. R ¹³ , R ¹⁴ , R ¹⁵ and R ¹⁶ each independently represents a substituent.

First, the compound represented by the general formula (5) will be described in detail.
Examples of the divalent linking group represented by each of L ¹ , L ² and L ³ include, for example, —CO—, —NR ^a — (R ^a is an alkyl group or a hydrogen atom), —O—, —S—. It is preferably a divalent linking group selected from the group consisting of, -SO-, -SO ₂ -and combinations thereof. More ^{preferably, -CO -, - NR a -} , - O -, - S -, - SO 2 - and a divalent linking group selected from these groups, still more preferably -CO -, - NR ^a A divalent linking group selected from the group consisting of-, -O-, -S- and -SO _2- , or a combination of two or three types of divalent linking groups selected from the group. Most preferably, it is a divalent linking group selected from the group consisting of —NR ^a —, —O— and —S—, or a combination of two or three types of divalent linking groups selected from the group.

The alkylene group represented by each of A ¹ , A ^2, and A ³ may be linear, branched, or substituted. The substituted or unsubstituted alkylene group is preferably an alkylene group having 2 to 30 carbon atoms. Examples thereof include —CH ₂ —, — (CH ₂ ) ₂ —, —CH ₂ CH (CH ₃ ). _{-, - CH 2 C (CH} 3) 2 - and - (CH _{2) 4} -) are included. Preferably _{- (CH 2) 2 -,} - CH 2 CH (CH 3) -, - (CH 2) 4 - a.

m ₂ , m ₃ and m ₄ each represent an integer of 0 or more, preferably 1 to 10, more preferably 1 to 5.

Examples of the organic group represented by each of R ¹⁰ , R ¹¹ and R ¹² include an alkyl group (a linear or branched substituted or unsubstituted alkyl group, preferably an alkyl group having 1 to 30 carbon atoms, such as methyl Group, ethyl group, n-propyl group, isopropyl group, t-butyl group, n-octyl group, dodecyl group, eicosyl group, 2-chloroethyl group, 2-cyanoethyl group, 2-ethylhexyl group, 2-hexyldecyl group, 2-octyldodecyl group, 3- (2,4-di-t-amylphenoxy) propyl group,

A 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, and a polycycloalkyl group such as a bicycloalkyl group. A group (preferably a substituted or unsubstituted bicycloalkyl group having 5 to 30 carbon atoms, such as a bicyclo (1.2.2) heptan-2-yl group, bicyclo (2.2.2) octane-3- Yl group), tricycloalkyl groups, and the like, preferably monocyclic cycloalkyl groups and bicycloalkyl groups, and monocyclic cycloalkyl groups are particularly preferred.

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 A group (preferably a substituted or unsubstituted cycloalkenyl group having 3 to 30 carbon atoms such as 2-cyclopenten-1-yl group, 2-cyclohexen-1-yl group, polycycloalkenyl group, preferably carbon A substituted or unsubstituted bicycloalkenyl group having a number of 5 to 30; for example, a bicyclo (2.2.1) hept-2-en-1-yl group, a bicyclo (2.2.2) oct-2-ene- A 4-yl group or a tricycloalkenyl group, particularly preferably a monocyclic cycloalkenyl group) or an alkynyl group (preferably a group having 2 to 30 carbon atoms). Or unsubstituted alkynyl group 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 a nitrogen atom, an oxygen atom and a sulfur atom are A heterocyclic group having at least one atom, more preferably a 5- or 6-membered aromatic heterocyclic group having 3 to 30 carbon atoms, such as a 2-furyl group, 2-thienyl group, 2-pyridyl group; 4-pyridyl group, 2-pyrimidinyl group, 2-benzothiazolyl group), and the like.

The organic group represented by each of R ¹⁰ , R ¹¹ and R ¹² may have a substituent, such as an aromatic heterocyclic group represented by Ar in the general formula (1) or It is synonymous with the group quoted as the substituent of the aromatic hydrocarbon ring group, and its preferred range is also the same. The substituent of the organic group represented by each of R ¹⁰ , R ¹¹ and R ¹² is particularly preferably a substituted or unsubstituted alkyl group or a substituted or unsubstituted aryl group.

  Among the compounds represented by the general formula (5), compounds represented by the following general formula (5a) are preferable.

In the general formula (5a), A ¹ , A ² and A ³ each independently represent an alkylene group, m ₂ , m ₃ and m ₄ represent an integer of 0 or more, and R ¹⁰ , R ¹¹ and R ¹² represent Each independently an organic group, when m ₂ is 0, R ¹⁰ is an alkyl group, when m ₃ is 0, R ¹¹ is an alkyl group, and when m ₄ is 0, R ¹² is an alkyl group It is.

In general formula (5a), A ¹ , A ² and A ³ , m ₂ , m ₃ and m ₄ , R ¹⁰ , R ¹¹ and R ¹² have the same meanings as in general formula (5), and the preferred ranges are also the same. It is.

Next, the compound represented by the general formula (6) will be described in detail.
In the formula, the divalent linking group represented by Z ⁴ includes an alkylene group, an alkenylene group, a divalent aryl group, a divalent heterocyclic residue, —CO—, —SO—, —SO ₂ — and the like. A divalent linking group selected from the group consisting of:

The substituent represented by each of R ¹³ , R ¹⁴ , R ¹⁵ and R ¹⁶ 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, t-butyl group, n-octyl group, dodecyl group, eicosyl group, 2-chloroethyl group, 2-cyanoethyl group, 2-ethylhexyl group, 2-to Xyldecyl group, 2-octyldodecyl group, 3- (2,4-di-t-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, and a 4-n-dodecylcyclohexyl group, and a multicycloalkyl group such as a bicycloalkyl group (preferably A substituted or unsubstituted bicycloalkyl group having 5 to 30 carbon atoms, such as a bicyclo (1.2.2) heptan-2-yl group or a bicyclo (2.2.2) octane-3-yl group) And a group having a polycyclic structure such as a tricycloalkyl group, preferably a monocyclic cycloalkyl group or a bicycloalkyl group, and a monocyclic cycloalkyl group is preferred.

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) and tricycloalkenyl groups, and monocyclic cycloalkenyl groups are preferred. Kiniru 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, 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 the ring-constituting atoms are Selected from a carbon atom, a nitrogen atom and a sulfur atom, and a heterogeneity of either a nitrogen atom, an oxygen atom or a sulfur atom A heterocyclic group having at least one child, 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. 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, t-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-t-amylphenoxy group, 4-t-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, trimethylsilyloxy group, t-butyldimethylsilyl group) An oxy group), a heterocyclic oxy group (preferably a substituted or unsubstituted heterocyclic oxy group having 2 to 30 carbon atoms, and the heterocyclic portion is preferably a heterocyclic portion described in the above heterocyclic group, for example, 1-phenyltetrazole-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 An oxy group, a pivaloyloxy group, a stearoyloxy group, a benzoyloxy group, a p-methoxyphenylcarbonyloxy group), a carbamoyloxy group (preferably a substituted or unsubstituted carbamoyloxy group having 1 to 30 carbon atoms such as N, N-dimethylcarbamoyloxy group, N, N-diethylcarbamoyloxy group, morpholinocarbonyloxy group, N, N-di-n-octylaminocarbonyloxy group, Nn-octylcarbamoyloxy group), alkoxycarbonyloxy group ( Preferably, A substituted or unsubstituted alkoxycarbonyloxy group having 2 to 30 primes, for example, a methoxycarbonyloxy group, an ethoxycarbonyloxy group, a t-butoxycarbonyloxy group, an n-octylcarbonyloxy group), an aryloxycarbonyloxy group (preferably, A substituted or unsubstituted aryloxycarbonyloxy group having 7 to 30 carbon atoms, such as 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-t-amylphenoxy) propylamino, 3- (2-ethylhexyloxy) propyl Amino group, 3- (2-hexyldecanooxy) propylamino group, 3-dodecyloxypropylamino group, 3- (3-perfluorohexylpropyloxy) propylamino group, 3- (3- (6H-perfluoro) Hexyl) propyloxy) propylamino group, anilino group, N-methyl-anilino group, diphenylamino group, 2-methyl Ruoxyanilino 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), acylamino group (preferably A formylamino group, a substituted or unsubstituted alkylcarbonylamino group having 1 to 30 carbon atoms, and a substituted or unsubstituted arylcarbonylamino group having 6 to 30 carbon atoms, such as formylamino group, acetylamino group, and 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, 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, t-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, methyl Ruhoniruamino group, butylsulfonyl group, phenylsulfonylamino group, 2,3,5-trichlorophenyl sulfonylamino group, p- methylphenyl sulfonylamino group), a 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 group, 1-phenyltetrazol-5-ylthio group), sulfamoyl group (preferably a substituent having 0 to 30 carbon atoms or An unsubstituted sulfamoyl group such as N-ethylsulfamoyl group, N- (3-dodecyloxy) Propyl) sulfamoyl group, N, N- dimethyl sulfamoyl mottle, N- acetyl sulfamoyl group, N- benzoylsulfamoyl group, N- (N'-phenylcarbamoyl) sulfamoyl group), a sulfo group,

Alkyl and arylsulfinyl groups (preferably substituted or unsubstituted alkylsulfinyl groups having 1 to 30 carbon atoms, substituted or unsubstituted arylsulfinyl groups having 6 to 30 carbon atoms such as methylsulfinyl group, ethylsulfinyl group, phenyl A sulfinyl group, a p-methylphenylsulfinyl group), an alkyl and an arylsulfonyl group (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, 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, 7 to 30 carbon atoms) Substituted or unsubstituted For example, an acetyl group, a pivaloyl group, a 2-chloroacetyl group, a stearoyl group, a benzoyl group, a pn-octyloxyphenylcarbonyl group), an aryloxycarbonyl group (preferably having 7 to 30 carbon atoms). A substituted or unsubstituted aryloxycarbonyl group such as phenoxycarbonyl group, o-chlorophenoxycarbonyl group, m-nitrophenoxycarbonyl group, pt-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, t-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), arylazo group and heterocyclic azo group (preferably substituted or unsubstituted arylazo group having 6 to 30 carbon atoms, substituted or unsubstituted heterocyclic azo group having 3 to 30 carbon atoms (heterocyclic moiety) Is preferably a heterocyclic moiety described in the above heterocyclic group A phenylazo group, a p-chlorophenylazo group, a 5-ethylthio-1,3,4-thiadiazol-2-ylazo group), an imide group (preferably a substituted or unsubstituted imide group having 2 to 30 carbon atoms). For example, 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 ), A phosphinyl 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, t-butyldimethylsilyl group, phenyldimethylsilyl group).

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

  These substituents may be further substituted with these substituents. Moreover, when it has two or more substituents, those substituents may be the same or different. If possible, they may be bonded to each other to form a ring.

R ¹³ , R ¹⁴ , R ¹⁵ and R ¹⁶ are preferably a substituted or unsubstituted amino group, an alkylamino group, an arylamino group or a heterocyclic amino group, more preferably a substituted or unsubstituted alkylamino group ( For example, methylamino group, dimethylamino group, 3-perfluorohexylpropylamino group, 3- (2,4-di-t-amylphenoxy) propylamino group, 3- (2-ethylhexyloxy) propylamino group, 3- (2-hexyldecanooxy) propylamino group, 3-dodecyloxypropylamino group, 3- (3-perfluorohexylpropyloxy) propylamino group, 3- (3- (6H-perfluorohexyl) propyloxy) Propylamino) group, arylamino group (for example, anilino group, N-methyl-anilino group, di Enylamino group, 2-methyloxyanilino group, 2- (3-perfluorohexylpropyloxy) anilino group, 2- (2-perfluorobutylethyloxy) anilino group, 2,4-di (2-perfluorohexyl) Ethyloxy) anilino group, 2- (6H-perfluorohexylmethyloxy) anilino group, 3,4-di (3-perfluorohexylpropyloxy) anilino group).

  Among the compounds represented by the general formula (6), a compound represented by the following general formula (6a) is particularly preferable.

In the general formula (6a), Z ⁵ represents a poly (alkyleneoxy) group, R ^a represents ^a hydrogen atom or an alkyl group, R ¹⁷ , R ¹⁸ , R ¹⁹ and R ²⁰ each independently represents a substituent, j1, j2, j3 and j4 each represents an integer of 0 to 5. When j1, j2, j3 and j4 are 2 or more, a plurality of R ¹⁷ , R ¹⁸ , R ¹⁹ and R ²⁰ may be the same or different, and may be bonded to each other to form a ring.

  j1, j2, j3 and j4 each represents an integer of 0 to 5. Preferably it is 1, 2 or 3.

Examples of the substituents represented by R ¹⁷ , R ¹⁸ , R ¹⁹ and R ²⁰ include the groups listed as R ¹³ , R ¹⁴ , R ¹⁵ and R ¹⁶ in the general formula (6). Preferred are a substituted or unsubstituted alkoxy group, an alkylthio group, an alkylamino group, and an arylamino group. More preferably, it is a substituted or unsubstituted alkoxy group (for example, methoxy group, ethoxy group, isopropoxy group, t-butoxy group, n-octyloxy group, 2-methoxyethoxy group, 1H, 1H, 9H-hexadecafluorononano Xyl group, 2-perfluorohexylethoxy group, 3-perfluorohexylpropyloxy group, 2-perfluorobutylethyloxy group, 6H-perfluorohexylmethyloxy group).

  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%.

[Liquid crystal compounds]
The optical compensation sheet of the present invention has optical anisotropy expressed by the orientation of the liquid crystal compound. In the optically anisotropic layer, the molecules of the liquid crystalline compound are preferably fixed in the alignment state, and more preferably fixed in the hybrid alignment state. There is no restriction | limiting in particular about the liquid crystalline compound used for this invention, A various compound can be used. It is preferable to use a rod-like liquid crystal compound or a discotic liquid crystal compound, and it is more preferable to use a discotic liquid crystal compound. The liquid crystal compound may be a polymer liquid crystal or a low molecular liquid crystal. Furthermore, the low molecular liquid crystalline compound is cross-linked when forming a layer, and includes those that no longer exhibit liquid crystallinity.

[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 the rod-shaped liquid crystalline compound of the present invention. In other words, the rod-like liquid crystalline compound may be bonded to a (liquid crystal) polymer. Regarding rod-like liquid crystalline compounds, for example, Quarterly Chemical Review Vol. 22, Liquid Crystal Chemistry (1994), Chapter 4, Chapter 7 and Chapter 11 of the Chemical Society of Japan and Liquid Crystal Device Handbook, Japan Society for the Promotion of Science, 142nd Committee The one described in Chapter 3 of the edition can be adopted.
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 an unsaturated polymerizable group or an epoxy group, more preferably an unsaturated polymerizable group, and most preferably an ethylenically unsaturated polymerizable group.

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

  The discotic liquid crystalline compound also includes a compound having a structure 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. 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 having a group that reacts with heat or light and, as a result, polymerized or cross-linked by reaction with heat or light, resulting in a high molecular weight and loss of liquid crystallinity. Preferred examples of the discotic liquid crystalline compound are described in JP-A-8-50206. Moreover, about superposition | polymerization of a discotic liquid crystalline compound, Unexamined-Japanese-Patent No. 8-27284 has description.

  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. However, when the polymerizable group is directly connected to the disc-shaped core, it becomes difficult to maintain the orientation state in the polymerization reaction. Therefore, a linking group is introduced between the discotic core and the polymerizable group. Therefore, the discotic liquid crystalline compound having a polymerizable group is preferably a compound represented by the following formula (III).

Formula (III)
D (-LQ) _n
In general formula (III), D is a discotic core, L is a divalent linking group, Q is a polymerizable group, and n is an integer of 4 to 12.

  An example of the disk-shaped core (D) is shown below. In each of the following examples, LQ (or QL) means a combination of a divalent linking group (L) and a polymerizable group (Q).

  In the hybrid alignment, the angle between the physical symmetry axis of the discotic liquid crystalline compound and the surface of the support, that is, the tilt angle is in the direction of the depth of the optically anisotropic layer (that is, perpendicular to the transparent support) and It increases or decreases with increasing distance from the plane of the polarizing film. The angle preferably decreases with increasing distance. In addition, the change in tilt angle can be continuous increase, continuous decrease, intermittent increase, intermittent decrease, change including continuous increase and continuous decrease, or intermittent change including increase and decrease. . The intermittent change includes a region where the inclination angle does not change in the middle of the thickness direction. Even if a region where the angle does not change is included, it may be increased or decreased as a whole. However, it is preferred that the tilt angle changes continuously.

  The average direction of the physical symmetry axis of the liquid crystal compound can be generally adjusted by selecting the material of the liquid crystal compound or the alignment film, or by selecting the rubbing treatment method. The physical symmetry axis direction of the liquid crystal compound on the surface side (air side) is represented by the general formula (1) used by selecting the type of the liquid crystal compound and together with the liquid crystal compound. It can be adjusted by the action of the compound.

  In addition to the liquid crystal compound, the compound represented by the general formula (1), and the compound having a 1,3,5-triazine ring group, the optically anisotropic layer may contain other additives. . Examples of other additives include plasticizers, surfactants, polymerizable monomers and polymers. These additives are preferably compatible with essential components such as a liquid crystal compound and contribute to control of the tilt angle of the liquid crystal compound or do not inhibit the alignment.

[Fluoroaliphatic group-containing polymer]
The optically anisotropic layer preferably further contains a fluoroaliphatic group-containing polymer. The fluoroaliphatic group-containing polymer can be contained in the composition (coating liquid) used when forming the optically anisotropic layer. The fluoroaliphatic group-containing polymer contributes to prevention of unevenness in the optically anisotropic layer. In the conventional large-sized liquid crystal display device, there was a problem of display unevenness due to the optical film, but by using the optical compensation sheet of the present invention, the unevenness of the large-sized liquid crystal display device was reduced and the image quality of the large-sized liquid crystal display device was reduced. Can be improved.

  In the present invention, as the fluoroaliphatic group-containing polymer, it is preferable to use a polymer containing at least one repeating unit derived from a monomer represented by the following general formula (3).

In the general formula (3), R ¹ represents a hydrogen atom or a methyl group, X represents an oxygen atom, a sulfur atom or —N (R ² ) —, H ^f represents a hydrogen atom or a fluorine atom, and R ² represents A hydrogen atom or an alkyl group having 1 to 4 carbon atoms, specifically a methyl group, an ethyl group, a propyl group, or a butyl group, and preferably a hydrogen atom or a methyl group. X is preferably an oxygen atom. m is an integer of 1-6, and 1 or 2 is preferable. n is an integer of 2 to 4, and 2 or 3 is preferable. The polymer may be a copolymer of a plurality of types of monomers represented by the general formula (3).
Although the example of the more specific monomer of the fluoro aliphatic group containing monomer represented by the said General formula (3) is given to the following, it is not this limitation.

  The fluoroaliphatic group-containing monomer can be produced by an electrolytic fluorination method, a telomerization method (telomer method) or an oligomerization method (oligomer method). Regarding the production method of these fluoroaliphatic compounds, for example, “Synthesis and Function of Fluorine Compounds” (Supervision: Nobuo Ishikawa, Issue: CMC Co., 1987), “Chemistry of Organic Fluorines Compounds”. II "(Monograph 187, Ed by Milos Hudricky and Attila E. Pavlath, American Chemical Society 1995). 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 (Scheme 2), 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.

  The fluoroaliphatic group-containing polymer may be a copolymer further containing a repeating unit derived from a monomer represented by the following general formula (4).

一般式（４）において、Ｒ³は水素原子又はメチル基を表し、Ｙは２価の連結基を表し、Ｒ⁴は置換もしくは無置換のポリ（アルキレンオキシ）基、置換基もしくは無置換の炭素数１〜２０の直鎖、又は炭素数４〜２０の分岐もしくは炭素数３〜２０の環状のアルキル基を示す。

In the general formula (4), R ³ represents a hydrogen atom or a methyl group, Y represents a divalent linking group, R ⁴ represents a substituted or unsubstituted poly (alkyleneoxy) group, a substituted or unsubstituted carbon. A linear alkyl group having 1 to 20 carbon atoms, a branched chain having 4 to 20 carbon atoms, or a cyclic alkyl group having 3 to 20 carbon atoms is shown.

The divalent linking group represented by Y is preferably an oxygen atom, a sulfur atom or —N (R ⁵ ) —. R ⁵ 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. R ⁵ is more preferably a hydrogen atom or a methyl group. Y is more preferably an oxygen atom, —N (H) — or —N (CH ₃ ) —.

The poly (alkyleneoxy) group which may have a substituent represented by R ⁴ can be represented by (RO) _x , where R is an alkylene group having 2 to 4 carbon atoms, for example —CH _{2 CH 2 -, - CH 2} CH 2 CH 2 -, - CH (CH 3) CH 2 - or _{-CH (CH 3) CH (CH} 3) - is preferably.
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. Good. It may be present as a linear or branched propyleneoxy or ethyleneoxy unit, a linear or branched propyleneoxy unit block or an ethyleneoxy unit block.

  In the poly (alkyleneoxy) chain, a plurality of poly (alkyleneoxy) units are one or more chain bonds (for example, —CONH—Ph—NHCO—, —S—, etc., where Ph represents a phenylene group) ) May be connected. If the chain bond has three or more valences, branched alkyleneoxy units can be obtained. The amount of the poly (alkyleneoxy) group compound is suitably 250 to 3,000.

Examples of the linear alkyl group having 1 to 20 carbon atoms, the branched chain having 4 to 20 carbon atoms, or the cyclic group having 3 to 20 carbon atoms represented by R ⁴ include a methyl group that may be linear and branched, ethyl Group, propyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonyl group, decyl group, undecyl group, dodecyl group, tridecyl group, tetradecyl group, pentadecyl group, octadecyl group, eicosanyl group, etc .; cyclohexyl group Monocyclic cycloalkyl groups such as cycloheptyl group; and polycyclic cycloalkyl groups such as bicycloheptyl group, bicyclodecyl group, tricycloundecyl group, tetracyclododecyl group, adamantyl group, norbornyl group, tetracyclodecyl group, etc. included.

The poly (alkyleneoxy) group or alkyl group represented by R ⁴ may be substituted, and examples of the substituent include a hydroxyl group, an alkylcarbonyl group, an arylcarbonyl group, an alkylcarbonyloxy group, a carboxyl group, and an alkyl ether group. , Aryl ether groups, halogen atoms such as fluorine atom, chlorine atom and bromine atom, nitro group, cyano group, amino group and the like, but not limited thereto.

The monomer represented by the general formula (4) is particularly preferably alkyl (meth) acrylate or poly (alkyleneoxy) (meth) acrylate.
Specific examples of the monomer represented by the general formula (4) are shown below, but not limited thereto.

  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 (Glico Products)), "Triton" (Toriton (Rohm and Haas)) and "PEG" (Daiichi Kogyo Seiyaku Co., Ltd.) Can be produced by reacting the products sold as) with acrylic acid, methacrylic acid, acrylic chloride, methacryl chloride, acrylic anhydride, etc. In addition, poly (oxyalkylenes) produced by known methods ) Diacrylate can also be used.

  Examples of the fluoroaliphatic group-containing polymer include a homopolymer of a monomer represented by the general formula (3), a monomer represented by the general formula (3), and a monomer represented by the general formula (4) ( More preferably, a copolymer with polyalkyleneoxy (meth) acrylate, more preferably polyethyleneoxy (meth) acrylate or polypropyleneoxy (meth) acrylate) is preferable.

  The fluoroaliphatic group-containing polymer used in the present invention may be a copolymer containing repeating units other than the repeating units derived from the monomers represented by the general formula (3) and the general formula (4). Good. A preferable copolymerization ratio of the monomer copolymerizable with each of the above monomers is 20 mol% or less, more preferably 10 mol% or less in all monomers. As such a monomer, those described in pages 1 to 483 of Chapter 2 of “Polymer Handbook 2nd ed., J. Brandrup, Wiley lnterscience (1975)” 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 (3) in the fluoroaliphatic group-containing polymer is preferably 5 mol% or more of the total amount of constituent monomers of the polymer, more preferably 20 The mol% or more, more preferably 30 mol% or more. The amount of the monomer represented by the general formula (4) in the fluoroaliphatic group-containing polymer of the present invention is preferably 10 mol% or more of the total amount of constituent monomers of the fluoroaliphatic group-containing polymer, more preferably It is 15-70 mol%, More preferably, it is 20-60 mol%.

The weight average molecular weight of the fluoroaliphatic group-containing polymer is preferably 3,000 to 100,000, more preferably 6,000 to 80,000.
Furthermore, the content of the fluoroaliphatic group-containing polymer in the composition for forming an optically anisotropic layer is preferably 0.005 to 8% by mass, more preferably 0.01 to 1% by mass. Yes, more preferably 0.05 to 0.5% by mass. By making the addition amount of the fluoroaliphatic group-containing polymer 0.005% by mass or more, a better one can be obtained, and by making the addition amount 8% by mass or less, the coating film cannot be sufficiently dried. Or adversely affecting the performance as an optical film (for example, uniformity of retardation) can be more effectively prevented.

The fluoroaliphatic group-containing polymer can be produced by a known 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 fluoro aliphatic group containing 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.

[Cellulose ester]
It is preferable to contain a cellulose ester in the optically anisotropic layer because the tilt angle of the molecules of the liquid crystal compound on the air interface side can be further increased. The cellulose ester also contributes to reducing the occurrence of cissing when the composition is applied on the support surface or the like. Preferred examples of the cellulose ester that can be used in the present invention include cellulose acetate, cellulose acetate butyrate, cellulose acetate propionate, hydroxypropyl cellulose, methyl cellulose, and carboxymethyl cellulose. Of these, cellulose acetate butyrate is preferable. The addition amount of the cellulose ester is a mass percentage with respect to the total amount of the liquid crystal compound, preferably 0.01 to 8%, more preferably 0.01 to 4%, and still more preferably 0.01 to 2%. .

[Method for producing optically anisotropic layer]
The optical compensation sheet of the present invention is obtained by applying a composition (usually a coating solution) containing a liquid crystalline compound and optionally other additives to the surface of the support, preferably the alignment film surface, to form molecules of the liquid crystalline compound. Can be produced by orienting and fixing in the oriented state. As a solvent used for preparing the coating solution, 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. When producing a highly uniform optical film, the surface tension of the coating solution is preferably 25 mN / m or less, and more preferably 22 mN / m or less.

  The coating liquid can be applied by a known method (eg, wire bar coating method, extrusion coating method, direct gravure coating method, reverse gravure coating method, die coating method).

  Next, an example of a coating / drying line in the case where the optical compensation sheet of the present invention is continuously produced in a long form is shown in FIGS. In the present invention, the coating liquid for forming an optically anisotropic layer is preferably applied after coating on a support having an alignment film on the surface (sometimes referred to as “web” or “strip-shaped flexible support”). Immediately after the drying, it is preferable to perform drying with a dryer having a casing surrounding the web while preventing turbulence in the vicinity of the coating surface and keeping the solvent vapor on the coating surface side during drying at a high concentration. The coating / drying line shown in FIGS. 1 to 5 is a conceptual diagram of a coating / drying line incorporating a drying apparatus capable of such drying.

  As shown in the figure, the coating / drying line 10 is mainly composed of a feeding device 14 for feeding a strip-shaped flexible support 12 wound in a roll shape, and a coating means for coating a coating liquid on the strip-shaped flexible support 12. 16, a dryer 18 for condensing and recovering the solvent in the coating solution of the coating film formed by coating on the belt-like flexible support 12, a ventilation drying means 20 for drying the coating film provided as necessary, and a coating / drying unit It is formed by a winding device 24 that winds up a product manufactured by drying, and a large number of guide rollers 22, 22... That form a conveyance path along which the belt-like flexible support 12 travels.

  The coating means 16 can be implemented by a known method (eg, slot / die coating method, wire bar coating method, extrusion coating method, direct gravure coating method, reverse gravure coating method, slide hopper coating method, curtain coating method).

  The application means 16 may be configured such that the application surface is on the upper side with respect to the horizontal direction as shown in FIG. 1 and FIG. It may be a simple configuration. Moreover, the structure which inclines with respect to a horizontal direction may be sufficient.

  The dryer 18 is composed of a condensing plate 30 that is a plate-like member provided in parallel with the belt-like flexible support 12 at a predetermined distance, and a side plate that hangs downward from the front and rear sides of the condensing plate 30. Is done. Thereby, when the solvent in the coating liquid of the coating film is volatilized, the volatilized solvent is condensed on the condensing plate 30 and collected.

  In the drying apparatus shown in FIG. 1, the space between the coating surface and the condensing plate 30 is a space in which two plates are sandwiched, and the solvent evaporates into the space, and the evaporated solvent is removed from the condensing plate 30. It is recovered from the condensation surface.

  In order to perform uniform drying of the coated surface, it is necessary that an undisturbed boundary layer is formed between the coated surface and the condensing surface of the condensing plate 30 to perform uniform mass transfer and heat transfer. However, natural thermal convection is generally known as an obstacle to uniform heat transfer between two planes having different temperatures as in the coating film drying apparatus of the present invention. When thermal natural convection occurs, this boundary layer becomes unstable and disturbs the boundary layer, resulting in a non-uniform drying rate distribution. As a result, the coating film cannot be uniformly dried. Research on natural convection has been conducted for a long time, for example, see Heat Transfer, vol. 1 (1953), Max Jacob (publisher: John Wiley & Sons), introduces experimental studies on natural convection in various cases. The Chemical Engineering Handbook, Revised Sixth Edition, edited by the Society of Chemical Engineering (Publisher: Maruzen), introduces research on natural convection.

  These relate to vertical flat plates, horizontal square plates, inclined flat plates, horizontal cylindrical surfaces, inclined cylindrical surfaces, gaps sandwiched between vertical flat plates, gaps sandwiched between horizontal flat plates, and the like. As is clear from these studies, the shape of the solid surface greatly affects the amount of heat transfer. However, these studies are mainly about plates or cylinders that are simply placed in the air. On the other hand, there are few studies on the problem between two planes, including the surface coated with coating liquid, where one side runs continuously, which is the subject of this study, and the conditions for the formation of a uniform boundary layer by suppressing natural convection Is not clear. In addition, since natural convection is convection caused by buoyancy of a fluid mass, the ratio of viscous force to buoyancy, the ratio of thermal diffusivity to momentum diffusivity, and the like are important. Each dimensionless number can be expressed in the following form.

Grasshof number = [thermal expansion coefficient × (T ₁ −T ₂ ) × L ³ × d ² × g] / δ ² (Formula 2)
Prandtl number = (specific heat capacity × δ) / thermal conductivity (Equation 3)
In general, the former (Formula 2) is called the Grasshof number, and the latter (Formula 3) is called the Prandtl number. The relationship between these values and the occurrence of natural convection is only an empirical formula for a specific case. A value obtained by multiplying these two dimensionless numbers is generally called a Rayleigh number.

  As a result of detailed research, in the coating film drying apparatus according to the present invention, the distance between the condenser plate and the strip-shaped flexible support, the temperature of the condenser plate, and the temperature of the coating film so that the Rayleigh number is less than 5000. Thus, a coating film having a good surface without drying unevenness can be obtained regardless of the type of solvent, the shape of the condenser plate 30, the arrangement angle of the condenser plate 30, the traveling angle of the strip-like flexible support 12, etc. It turns out that it is obtained.

  When each condition is set so that the number of Rayleigh is less than 2000, the surface properties of the coating film are further improved.

  The material used for condensing the solvent of the condensing plate 30 is not particularly limited, such as metal, plastic, wood, etc., but when the coating solution contains an organic solvent, it is a material resistant to the organic solvent. It is desirable to use a coating on the surface.

  In the dryer 18, the means for recovering the solvent condensed on the condensing plate 30, for example, provides a groove on the condensing surface of the condensing plate 30 and recovers the solvent using capillary force. The direction of the groove may be the traveling direction of the belt-like flexible support 12 or may be a direction orthogonal to this. When the condensing plate 30 is inclined, the grooves may be provided in a direction in which the solvent can be easily recovered.

  In addition to the configuration in which the condensing plate 30 which is a plate-like member is employed for the dryer 18, a configuration having a similar function, for example, a configuration using a perforated plate, a net, a scissors, a roll, or the like can be employed. Moreover, you may use together with the collection | recovery apparatuses as shown by US5694701.

  The dryer 18 is preferably arranged as close as possible to the coating means 16 in order to prevent uneven drying of the coating film due to the occurrence of natural convection immediately after the coating liquid is applied. Specifically, the inlet of the dryer 18 is preferably disposed so as to be within a position of 5 m from the coating means 16, more preferably disposed within a position of 2 m, and within 0.7 m. Most preferably, it is disposed so as to be positioned.

  For the same reason, the running speed of the strip-shaped flexible support 12 is preferably a speed at which the strip-shaped flexible support 12 reaches the dryer 18 within 30 seconds after coating by the coating means 16. It is more preferable that the speed reaches the dryer 18 within a second.

  The larger the coating amount and the coating film thickness of the coating solution, the more easily the unevenness occurs because the flow inside the coating film is more likely to occur, but according to the present invention, even when the coating amount and the coating film thickness are large. A sufficient effect can be obtained. If the thickness of the coating film is 0.001 to 0.08 mm, it can be dried uniformly and efficiently.

  If the running speed of the belt-like flexible support 12 is too high, the boundary layer near the coating film is disturbed by the accompanying wind, which adversely affects the coating film. Therefore, the running speed of the belt-like flexible support 12 is preferably set to 1 to 100 m / min, and more preferably set to 5 to 80 m / min.

  Since unevenness of the coating film is particularly likely to occur at the initial stage of drying, it is preferable that the dryer 18 condenses and collects 10% or more of the solvent in the coating solution, and the remaining coating solution is dried by the air drying means 20. What percentage of the solvent in the coating solution is condensed and recovered may be determined by comprehensively determining the influence on the drying unevenness of the coating film, production efficiency, and the like.

  In order to promote evaporation and condensation of the solvent in the coating solution, it is preferable to heat the belt-like flexible support 12 and / or the coating film, cool the condensation plate 30, or both means. For example, the cooling means is disposed in the dryer, and the heating means is disposed on the opposite side of the dryer 18 with the belt-like flexible support 12 interposed therebetween.

  In any case, it is desirable that the temperature is controlled in order to control the drying rate of the coating film. The condenser plate 30 can be controlled in temperature, and if it is desired to cool, it is necessary to install equipment for cooling. For cooling, a water-cooled heat exchanger system using a refrigerant or the like, an air-cooled system using wind, a system using electricity, for example, a system using a Peltier element, or the like can be used.

  In the case where it is desired to heat the belt-like flexible support 12 and / or the coating film, a heater can be provided on the anti-coating film side for heating. Moreover, it can also heat by arrange | positioning the conveyance roll (heating roll) which can be heated up. In addition, you may heat using an infrared heater, a microwave heating means, etc.

  When determining the temperature of the strip-shaped flexible support 12, the coating film, and the condensing plate 30, it is necessary to pay attention to the fact that the evaporated solvent is condensed on a place other than the condensing plate 30, for example, on the surface of the transport roll. It is something that must be avoided. For this reason, for example, this kind of dew condensation can be avoided by setting the temperature of the part other than the condenser plate 30 higher than the temperature of the condenser plate 30.

  The distance (interval) between the surface of the coating film and the surface of the condensing plate 30 of the dryer 18 needs to be adjusted to an appropriate distance in consideration of the drying speed of the desired coating film. Shortening the distance increases the drying speed, but is easily affected by the set distance accuracy. On the other hand, when the distance is increased, not only the drying speed is significantly reduced, but also natural convection due to heat occurs, resulting in drying unevenness.

  The distance between the surface of the coating film and the surface of the condensing plate 30 of the dryer 18 needs to be determined within a range that satisfies the condition that the number of Rayleigh expressed by the formula (1) is less than 5000, but is in the range of 0.1 to 200 mm. It is preferable to adjust in the range of 0.5 to 100 mm.

  In the dryer 18, a number of guide rollers 22, 22... Are provided on the opposite side of the condensing plate 30 with the belt-like flexible support 12 interposed therebetween, and the configuration shown in FIGS. The configuration shown in FIGS. 1A and 2A in which the guide rollers 22 are not provided may be employed.

  The dryer 18 does not necessarily have a linear shape as shown in FIG. 1, and may be an arc-shaped dryer 26 as shown in FIG. 2, for example. Further, a large drum may be provided, and a dryer may be disposed thereon.

  In the example shown in FIG. 2, the arc-shaped dryer 26 is brought close to the coating means 16 to improve the solvent recovery efficiency.

  As the ventilation drying means 20, a roller conveying dryer type or air floating dryer type drying apparatus used as a conventional technique can be used. Any type of drying apparatus is common in that dried air is supplied to the surface of the coating film to dry the coating film.

  In addition, the method of drying an application film only with the dryer 18 without providing the ventilation drying means 20 can also be taken. 3, 4, and 5 are examples of configurations in which the coating film is dried only by the dryer 18.

   In the example of FIG. 3, the dryer 18 is divided into a plurality of zones, and the distance between the condenser plate 30 and the coating film is changed stepwise in each zone. Further, a large number of guide rollers 22, 22... Are provided on the opposite side of the condensing plate 30 with the belt-like flexible support 12 interposed therebetween.

   In the example of FIG. 4, the dryer 18 is divided into a plurality of zones, and the distance between the condenser plate 30 and the coating film is changed stepwise in each zone. No guide rollers 22, 22 ... are provided.

   In the example of FIG. 5, the dryer 18 is not divided into a plurality of zones, and the distance between each condenser plate 30 and the coating film is constant. Further, a large number of guide rollers 22, 22... Are provided on the opposite side of the condensing plate 30 with the belt-like flexible support 12 interposed therebetween.

  In addition, conventional members are used for the feeding device 14, the guide roller 22, the winding device 24, etc. used in the coating / drying line 10 incorporating the drying device to which the coating film drying method and apparatus of the present invention is applied. They are used and their explanation is omitted.

  According to the drying method and apparatus detailed above, the coating film can be efficiently and uniformly dried while suppressing unevenness occurring in the coating film immediately after coating. In addition, the layout of the coating and drying process is not greatly changed, and further, the physical properties of the coating liquid and the type of solvent are not restricted, so that the coating liquid prescription means can be designed flexibly.

  Moreover, according to the coating film drying method and apparatus, energy saving and cost reduction are also effective. That is, among the evaporated gas generated in the coating / drying line, a solvent other than water cannot be released as it is to the atmosphere, so the evaporated gas needs to be liquefied and recovered, and a solvent gas recovery facility for that purpose is required. However, in the coating / drying line 10, the solvent can be directly recovered in a liquid state by a dryer that condenses and recovers a part of the coating liquid, so that the load on the solvent gas recovery facility can be reduced.

  Simultaneously with the drying step or after the drying step, the liquid crystalline compound is brought into a desired alignment state, and then fixed in the alignment state to form an optically anisotropic layer. As described above, it is preferable that the molecules of the liquid crystalline compound are once horizontally aligned and then hybrid aligned, and the transition from horizontal alignment to hybrid alignment is promoted, for example, by increasing the alignment temperature.

  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. The coating solution preferably contains a polymerizable monomer or a polymerization initiator that contributes to the fixation of the liquid crystalline compound. As the polymerizable monomer, for example, a compound having a vinyl group, a vinyloxy group, an acryloyl group, and a methacryloyl group is preferable. Generally the addition amount of the said compound is 1-50 mass% with respect to a liquid crystalline compound, and it is preferable that it is 5-30 mass%. In addition, when a monomer having 3 or more polymerizable reactive functional groups is mixed and used, adhesion between the alignment film and the optically anisotropic layer can be improved.

Examples of photopolymerization initiators include α-carbonyl compounds (described in US Pat. Nos. 2,367,661 and 2,367,670), acyloin ethers (described in US Pat. No. 2,448,828), α-hydrocarbon substituted aromatic acyloin compounds ( US Pat. No. 2,722,512), a polynuclear quinone compound (described in US Pat. Nos. 3,046,127 and 2,951,758), a combination of triarylimidazole dimer and p-aminophenyl ketone (described in US Pat. No. 3,549,367), acridine Phenazine compounds (described in JP-A-60-105667 and US Pat. No. 4,239,850) and oxadiazole compounds (described in US Pat. No. 4,221,970) are included.
The amount of the photopolymerization initiator used is preferably 0.01 to 20% by mass, more preferably 0.5 to 5% by mass, based on the solid content of the coating solution.

It is preferable to use ultraviolet rays for light irradiation for polymerization of liquid crystalline molecules. The irradiation energy is preferably in the range of ^{20mJ / cm 2 ~50J / cm 2} , more preferably in the range of ^{20mJ / cm 2 ~5000mJ / cm 2} , a range of 100mJ / cm ² ~800mJ / cm ² More preferably. In order to accelerate the photopolymerization reaction, light irradiation may be performed under heating conditions.

  The thickness of the optically anisotropic layer thus formed is preferably 0.1 to 20 μm, more preferably 0.5 to 15 μm, and most preferably 1 to 10 μm. A protective layer may be provided on the optically anisotropic layer.

[Alignment film]
An alignment film is preferably used for forming the optically anisotropic layer. The alignment film used for forming the optically anisotropic layer is not particularly limited, and an alignment formed by rubbing the surface of the polymer layer in a predetermined direction after forming a polymer layer such as polyvinyl alcohol. A membrane can be used. A preferred example of the alignment film is described in JP-A-8-338913. The thickness of the alignment film is preferably 10 μm or less. The alignment film may be used only at the time of forming the optically anisotropic layer, and after the optically anisotropic layer is formed, it may be peeled off if possible. In such a case, after forming an alignment film on the temporary support and forming an optically anisotropic layer on the alignment film, the optically anisotropic layer is transferred to a transparent support, and the optical compensation of the present invention is performed. A sheet may be produced.

[Transparent support]
The optical compensation sheet of the present invention has a support that supports the optically anisotropic layer. The support is preferably 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 acetate, cellulose diacetate), norbornene-based polymers, and polymethyl methacrylate. A commercially available polymer (for Norbornene-based polymers, both Arton and Zeonex are trade names)) may be used.
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. Particularly, the number of carbon atoms is preferably 2 (cellulose acetate), 3 (cellulose propionate) or 4 (cellulose butyrate). Cellulose acetate is particularly preferred. Mixed fatty acid esters such as cellulose acetate propionate and cellulose acetate butyrate may be used.

In addition, even for polymers that are easily known to exhibit birefringence, such as polycarbonate and polysulfone, which are conventionally known, the birefringence expression can be controlled by modifying the molecule as described in the specification of WO00 / 26705. Then, it can also be used for the optical film of the present invention.
When the optical film of the present invention is used for a polarizing plate protective film or a retardation film, it is preferable to use cellulose acetate having an acetylation degree of 55.0 to 62.5% as the polymer film. 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).
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. The specific value of Mw / Mn is preferably 1.0 to 1.7, more preferably 1.0 to 1.65, and most preferably 1.0 to 1.6. preferable.

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 6-position substitution degree of cellulose is the same as or higher than that of the 2-position and 3-position.
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.
The degree of substitution at each position can be measured by NMR.
Cellulose acetate having a high degree of substitution at the 6-position is described in Synthesis Example 1 described in Paragraph Nos. 0043 to 0044, Synthesis Example 2 described in Paragraph Nos. 0048 to 0049, and Paragraph Nos. 0051 to 0052. It can be synthesized with reference to the method of Synthesis Example 3.

  The optical compensation sheet of the present invention can be used alone as a member of a liquid crystal display device, but can also be integrated with a polarizing plate and incorporated into a liquid crystal display device as one member in the polarizing plate. The polarizing plate in which the optical compensation sheet of the present invention is integrated not only has a polarizing function but also contributes to an increase in the viewing angle of the liquid crystal display device. Furthermore, the use of the polarizing plate using the optical compensation sheet of the present invention as a protective film for the polarizing film contributes to the thinning of the liquid crystal display device.

Hereinafter, the polarizing plate to which the optical compensation sheet of the present invention is added will be described in detail.
[Polarizer]
In general, a polarizing plate has a polarizing film produced by adsorbing and orienting a dichroic substance on a base film and a protective film bonded to at least one surface of the polarizing film. As a polymer used for the base film of the polarizing film, a polyvinyl alcohol (hereinafter referred to as PVA) polymer is generally used. As the dichroic substance, iodine or a dichroic dye is used alone or in combination. As the protective film, physical properties such as low birefringence, transparency, moderate moisture permeability, and dimensional stability are required, and conventionally, cellulose acetate film has been widely used, and methylene chloride, which is a chlorinated organic solvent, is used in the production thereof. The improvement is desired from the viewpoint of environmental conservation. A cellulose acylate film produced using a non-chlorine organic solvent is obtained by casting the film with a non-chlorine solvent to produce a film.

  Here, the PVA used for the polarizing film is usually saponified polyvinyl acetate, but can be copolymerized with vinyl acetate such as unsaturated carboxylic acid, unsaturated sulfonic acid, olefins, and vinyl ethers. You may contain a component. In addition, modified PVA containing an acetoacetyl group, a sulfonic acid group, a carboxyl group, an oxyalkylene group, or the like can also be used. The degree of saponification of PVA is not particularly limited, but is preferably 80 to 100 mol%, particularly preferably 90 to 100 mol% from the viewpoints of solubility, polarization, heat resistance, moisture resistance, and the like. The degree of polymerization of PVA is not particularly limited, but is preferably 1000 to 10,000, and particularly preferably 1500 to 5000, from the viewpoint of film strength, heat resistance, moisture resistance, stretchability, and the like. Moreover, it does not specifically limit about the syndiotacticity of PVA, It can also take arbitrary values according to the objective.

  In order to prepare a polarizing film by dyeing and stretching PVA, a method of stretching a PVA film as a raw fabric in a dry or wet manner and then immersing it in a solution of iodine or dichroic dye, iodine or dichroic dye There are a method of stretching and orienting a PVA film in the above solution, a method of stretching and orienting a PVA film in iodine or a dichroic dye, and then stretching and orienting it in a wet or dry manner. Moreover, when forming a PVA raw fabric by a solution casting method, a method of previously containing a dichroic substance in the PVA solution can be used.

  A manufacturing method by wet stretching of a typical polarizing plate will be described below. First, the raw fabric PVA film is pre-swelled with an aqueous solution. Subsequently, it is immersed in the solution of a dichroic substance, and a dichroic substance is adsorbed. Further, it is uniaxially stretched in the traveling direction in an aqueous solution of a boron compound such as boric acid. If necessary, a color adjustment bath, a curing bath or the like may be provided after this. When it is dried to some extent, a protective film is bonded using an adhesive such as PVA. Furthermore, it dries and a polarizing plate is obtained.

  Various organic solvents, inorganic salts, plasticizers, boric acids and the like may be added to the pre-swelled solution in the aqueous solution.

  As an example of the case where iodine is used as the dichroic substance, an iodine-potassium iodide aqueous solution is used as the staining liquid. Iodine is preferably 0.1 to 20 g / liter, potassium iodide is preferably 1 to 100 g / liter, and the weight ratio of iodine and potassium iodide is preferably 1 to 100. The dyeing time is preferably 30 to 5000 seconds, and the liquid temperature is preferably 5 to 50 ° C. It is also preferable to include a compound that crosslinks PVA such as a boron compound in the dyeing solution. The boron compound in the stretching bath is particularly preferably boric acid. The boric acid concentration is preferably 1 to 200 g / liter, more preferably 10 to 120 g / liter. In addition to the boron compound, the stretching bath can contain an inorganic salt such as potassium iodide, various organic solvents, or a dichroic dye. In addition to the dichroic dye, an inorganic salt such as potassium iodide, a boron compound, and the like are contained in the color adjustment bath and the curing bath as necessary.

  As a PVA stretching process, as exemplified above, it is common to apply tension in the traveling direction of the continuous film, and stretch and orient the film in the traveling direction. A method of applying tension in the width direction and orienting in the width direction is also applicable. The stretching is preferably performed 3 times or more in a uniaxial direction, and more preferably 4.5 times or more. Biaxial stretching may be performed depending on the purpose of use of the polarizing film. Although the film thickness after extending | stretching is not specifically limited, 5-100 micrometers is preferable from a viewpoint of a handleability, durability, and economical efficiency, and 10-40 micrometers is more preferable. The temperature during stretching varies depending on the stretching conditions, but is usually 10 to 250 ° C. When dry stretching at a temperature of 100 ° C. or higher, it is preferably performed in an inert gas atmosphere such as nitrogen. Further, it is preferable to perform a crystallization treatment at a temperature of 100 ° C. or higher before dyeing a previously stretched film.

  As the dyeing method, not only the immersion method exemplified above, but also any means such as application or spraying of iodine or a dye solution is possible. In addition to the liquid layer adsorption described above, adsorption by donation can be performed as necessary. It is also preferable to dye with a dichroic dye. Specific examples of dichroic dyes include, for example, dye compounds such as azo dyes, stilbene dyes, pyrazolone dyes, triphenylmethane dyes, quinoline dyes, oxazine dyes, thiazine dyes, and anthraquinone dyes. I can give you. A water-soluble one is preferred, but not limited thereto. Further, it is preferable that a hydrophilic substituent such as a sulfonic acid group, an amino group, or a hydroxyl group is introduced into these dichroic molecules.

  Typical examples of dichroic molecules include C.I. Eye. direct. Yellow 12, sea. Eye. direct. Orange 39, sea. Eye. direct. Orange 72, sea. Eye. direct. Red 28, Sea. Eye. direct. Red 39, Sea. Eye. direct. Red 79, Sea. Eye. direct. Red 81, Sea. Eye. direct. Red 83, Sea. Eye. direct. Red 89, Sea. Eye. direct. Violet 48, C.I. Eye. direct. Blue 67, Sea. Eye. direct. Blue 90, Sea. Eye. direct. Green 59, Sea. Eye. Acid. Red 37 and the like, and further, JP-A-1-161202, JP-A-1-172906, JP-A-1-172907, JP-A-1-183602, JP-A-2000-48105, JP-A-2000-65205, Examples thereof include the dyes described in JP-A-7-261024. In particular, Sea. Eye. direct. Red 28 (Congo Red) has long been known as preferred for this application. These dichroic molecules are used as free acids or alkali metal salts, ammonium salts, and salts of amines.

  By blending two or more of these dichroic molecules, it is possible to produce polarizers having various hues. As a polarizing element or polarizing plate, a compound (pigment) that exhibits black when the polarization axes are orthogonal to each other and a mixture of various dichroic molecules so as to exhibit black are excellent in terms of both single-plate transmittance and polarization rate, and are preferable.

  From the viewpoint of increasing the heat resistance and moisture resistance of the polarizing film, it is preferable to include an additive that crosslinks PVA in the manufacturing process of the polarizing film. As the crosslinking agent, those described in US Reissue Patent No. 232897 can be used, but boric acid and borax are preferably used practically. In addition, it is known that the polarizing film contains a metal salt such as zinc, cobalt, zirconium, iron, nickel, manganese, etc., because it is known to improve durability. These cross-linking agents and metal salts may be contained in any of the above-described pre-swelling bath, dichroic material dyeing bath, stretching bath, curing bath, color adjusting bath, etc., and the order of the steps is particularly limited. Not. The adhesive that bonds the protective film and the polarizing film is not particularly limited, and any known adhesive such as PVA, modified PVA, urethane, or acrylic can be used. The thickness of the adhesive layer is preferably from 0.01 to 20 μm, more preferably from 0.1 to 10 μm.

  The optical compensation sheet of the present invention (so that the support surface is in contact with the polarizing film) is bonded to one surface of the polarizing film, and a polymer film made of cellulose acylate or the like is disposed on the opposite surface. (The arrangement of optically anisotropic layer / polarizing film / polymer film) is preferred.

  The optical compensation sheet of the present invention can be used in various liquid crystal display devices. When the optical compensation sheet of the present invention is disposed in a liquid crystal display device having a liquid crystal cell and a pair of polarizing films sandwiching the liquid crystal cell, the optical compensation sheet is interposed between at least one of the pair of polarizing films and the liquid crystal cell. It is preferable to arrange. The optical compensation sheet of the present invention preferably determines the optical characteristics of the optically anisotropic layer so as to compensate for the liquid crystalline compound in the liquid crystal cell in the black display of the liquid crystal display device. Since the alignment state of the liquid crystalline compound in the liquid crystal cell in black display varies depending on the mode of the liquid crystal display device, the preferred range of the optical characteristics of the optically anisotropic layer also varies depending on the application. The alignment state of the liquid crystal compound in the liquid crystal cell is described in IDW'00, FMC7-2, P411 to 414, and the like.

  As described above, the preferred range of the optical characteristics of the optical compensation sheet of the present invention varies depending on the application, for example, which mode of the liquid crystal cell is used for optical compensation. In general, Re of the optically anisotropic layer is preferably 0 to 70 nm, more preferably 20 to 70 nm, Rth is preferably 50 to 400 nm, and 100 to 400 nm. More preferred. In order to form an optically anisotropic layer exhibiting such optical characteristics, for example, when a discotic liquid crystalline compound is used and the optically anisotropic layer is formed while being fixed in a hybrid orientation, the minimum inclination angle is 0 to 90 °. The hybrid orientation is preferably (more preferably 0 to 60 °) and the maximum inclination angle is 30 to 90 ° (more preferably 50 to 90 °). The Re of the transparent support is preferably from 0 to 70 nm, more preferably from 0 to 50 nm, and Rth is preferably from 10 to 400 nm, more preferably from 40 to 250 nm. However, this is an example, and the optical characteristics of the optical compensation sheet of the present invention are not limited to this range.

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 of λ nm incident from the direction inclined + 40 ° with respect to the film normal direction with the Re, in-plane slow axis (determined by KOBRA 21ADH) as the tilt axis (rotation axis). The retardation value and the retardation value measured by making light of 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 the 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.

Hereinafter, preferred embodiments of the optical compensation sheet of the present invention in the liquid crystal display device in each liquid crystal mode will be described.
(TN mode liquid crystal display)
The TN mode liquid crystal cell is most frequently used as a color TFT liquid crystal display device, and is described in many documents. The alignment state in the liquid crystal cell in the TN mode black display is an alignment state in which a rod-like liquid crystalline molecule rises at the center of the cell and the rod-like liquid crystalline compound lies in the vicinity of the cell substrate.

  The rod-like liquid crystalline compound in the center of the cell is compensated with a discotic liquid crystalline compound of the homeotropic orientation (horizontal orientation in which the disk surface is lying) or a (transparent) support, and the rod-like liquid crystalline property in the vicinity of the cell substrate The compound can be compensated with a discotic liquid crystalline compound having a hybrid alignment (an alignment in which the inclination of the major axis changes with the distance from the polarizing film). In addition, the rod-like liquid crystalline compound at the center of the cell is compensated with a rod-like liquid crystalline compound having a homogeneous orientation (horizontal orientation in which the major axis lies) or a (transparent) support, and the rod-like liquid crystalline property in the vicinity of the cell substrate The compound can be compensated with a discotic liquid crystalline compound having a hybrid alignment.

The homeotropic alignment liquid crystal compound is aligned in a state where the angle between the average alignment direction of the major axis of the liquid crystal compound and the plane of the polarizing film is 85 to 95 degrees.
The liquid crystal compound of homogeneous alignment is aligned with the angle between the average alignment direction of the major axis of the liquid crystal compound and the plane of the polarizing film being less than 5 degrees.
In the hybrid alignment liquid crystalline compound, the angle between the long axis average alignment direction of the liquid crystalline compound and the plane of the polarizing film is preferably 15 degrees or more, and more preferably 15 degrees to 85 degrees.

Optically anisotropic layer in which support or discotic liquid crystalline compound is homeotropically oriented, optically anisotropic layer in which rod-like liquid crystalline compound is homogeneously oriented, and homeotropically oriented discotic liquid crystalline compound And an optically anisotropic layer made of a mixture of rod-like liquid crystalline compounds that are homogeneously oriented have Rth retardation values defined by the above formula of 40 nm to 200 nm, and Re retardation values defined by the above formula of 0 to 0. It is preferably 70 nm.
Regarding the discotic liquid crystal compound layer having homeotropic alignment (horizontal alignment) and the rod-like liquid crystal compound layer having homogeneous alignment (horizontal alignment), Japanese Patent Laid-Open Nos. 2000-304931 and 2000-304932 Are listed. The discotic liquid crystal compound layer having a hybrid orientation is described in JP-A-8-50206.

(OCB mode liquid crystal display)
The OCB mode liquid crystal cell is a bend alignment mode liquid crystal cell in which a rod-like liquid crystal compound is aligned in a substantially opposite direction (symmetrically) between an upper portion and a lower portion of the liquid crystal cell. Liquid crystal display devices using a bend alignment mode liquid crystal cell are disclosed in US Pat. Nos. 4,583,825 and 5,410,422. Since the rod-like liquid crystal compounds are symmetrically aligned at the upper and lower portions of the liquid crystal cell, the bend alignment mode liquid crystal cell has a self-optical compensation function. Therefore, this liquid crystal mode is called an OCB (Optically Compensatory Bend) liquid crystal mode.
Similarly to the TN mode, the liquid crystal cell in the OCB mode is in a black display, and the alignment state in the liquid crystal cell is such that the rod-like liquid crystal compound rises at the center of the cell and the rod-like liquid crystal compound lies in the vicinity of the cell substrate. .

  Since the TN mode and the alignment of the liquid crystal are the same in black display, the preferred mode is the same for the TN mode. However, since the OCB mode has a larger range in which the liquid crystal compound has risen at the center of the cell than the TN mode, an optically anisotropic layer in which the discotic liquid crystal compound is homeotropically aligned or a rod-like liquid crystal It is necessary to slightly adjust the retardation value of the optically anisotropic layer in which the functional compound is homogeneously oriented. Specifically, the optically anisotropic layer in which the discotic liquid crystalline compound on the (transparent) support is homeotropically aligned, or the optically anisotropic layer in which the rod-like liquid crystalline compound is homogeneously aligned is Rth The retardation value is preferably 150 nm to 500 nm, and the Re retardation value is preferably 20 to 70 nm.

  The optically anisotropic layer in which the support or the discotic liquid crystalline compound is homeotropically oriented, or the optically anisotropic layer in which the rod-like liquid crystalline compound is homogeneously oriented has an Rth retardation value of 150 nm to 500 nm. The Re retardation value is preferably 20 to 70 nm.

(Other liquid crystal display devices)
The ECB mode and STN mode liquid crystal display devices can be optically compensated in the same way as described above.

The present invention will be described more specifically with reference to the following examples. The materials, reagents, ratios, operations and the like shown in the following examples can be appropriately changed without departing from the spirit of the present invention. Therefore, the scope of the present invention is not limited to the specific examples shown below.
[Example 1]
(Production of polymer substrate)
The following composition was put into a mixing tank and stirred while heating to 30 ° C. to dissolve each component to prepare a cellulose acetate solution.
────────────────────────────────────
Cellulose acetate solution composition (parts by mass) Inner layer Outer layer ────────────────────────────────────
Cellulose acetate with an acetylation degree of 60.9% 100 parts by weight 100 parts by weight Triphenyl phosphate (plasticizer) 7.8 parts by weight 0.8 parts by weight Biphenyl diphenyl phosphate (plasticizer)
3.9 parts by mass 3.9 parts by mass Methylene chloride (first solvent) 293 parts by mass 314 parts by mass Methanol (second solvent) 71 parts by mass 76 parts by mass 1-butanol (third solvent) 1.5 parts by mass 6 parts by mass Silica fine particles (AEROSIL R972, manufactured by Nippon Aerosil Co., Ltd.)
0 parts by mass 0.8 parts by mass The following retardation increasing agent 1.4 parts by mass 0 parts by mass ────────────────────────────── ───────

  The obtained inner layer dope and outer layer dope were cast on a drum cooled to 0 ° C. using a three-layer co-casting die. The film having a residual solvent amount of 70% by mass was peeled off from the drum, both ends were fixed with a pin tenter, and the film was dried at 80 ° C. while transporting at a draw ratio of 110% in the transport direction, resulting in a residual solvent amount of 10%. By the way, it was dried at 110 ° C. Thereafter, it was dried at a temperature of 140 ° C. for 30 minutes to produce a cellulose acetate film (outer layer: 3 μm, inner layer: 74 μm, outer layer: 3 μm) having a residual solvent of 0.3% by mass. The optical properties of the produced cellulose acetate film (CF-02) were measured.

The obtained polymer substrate (PK-1) had a width of 1340 mm and a thickness of 80 μm. It was 8 nm when the retardation value (Re) in wavelength 630nm was measured using the ellipsometer (M-150, JASCO Corporation make). Moreover, it was 93 nm when the retardation value (Rth) in wavelength 630nm was measured.
The produced polymer substrate (PK-1) was immersed in a 2.0N potassium hydroxide solution (25 ° C.) for 2 minutes, neutralized with sulfuric acid, washed with pure water and dried. The surface energy of this PK-1 was determined by the contact angle method and found to be 63 mN / m.
On this PK-1, an alignment film coating solution having the following composition was coated at a coating amount of 28 ml / m ² with a # 16 wire bar coater. Drying was performed with warm air of 60 ° C. for 60 seconds, and further with warm air of 90 ° C. for 150 seconds.

(Orientation film coating solution 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

  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).

(Preparation of coating solution for optically anisotropic layer)
The following composition was dissolved in 102 kg of methyl ethyl ketone to prepare a coating solution.
The following discotic liquid crystalline compound (1) 41.01 parts by mass Ethylene oxide-modified trimethylolpropane triacrylate (V # 360, manufactured by Osaka Organic Chemical Co., Ltd.) 4.06 parts by mass Exemplified compound of general formula (1) ( II-1) 0.08 parts by mass Exemplified compound having 1,3,5-triazine ring (H-16) 0.12 parts by mass Photopolymerization initiator (Irgacure 907, manufactured by Ciba Geigy Corporation) 1.35 parts by mass Sensitizer (Kayacure DETX, manufactured by Nippon Kayaku Co., Ltd.) 0.45 parts by mass

The upstream lip land length IUP of the slot die was 1 mm, and the downstream lip land length ILO was 50 μm. Using this slot die, the coating solution was applied at 5 ml / m ² on the web so that the wet film thickness was 5 μm. The coating speed was 50 m / min. The cellulose acetate film coated with the alignment film was used as the web, and the length of the gap between the downstream lip land and the cellulose triacetate substrate as the web was set to 40 μm. The surface of the alignment film application surface was subjected to a rubbing treatment and conveyed to the application process as it was for application. In the rubbing treatment, the alignment film was rubbed in a direction parallel to the slow axis (measured at a wavelength of 632.8 nm) of the cellulose acetate film. The rotational peripheral speed of the rubbing roller in the rubbing treatment was 5.0 m / sec, and the pressing pressure against the alignment layer resin layer was set to 9.8 × 10 ⁻³ Pa.

The composition of the optically anisotropic layer shown below was used for the coating liquid. The coating speed was 50 m / min. Immediately after coating, initial drying was performed using the dryer 18 shown in FIG. The total length of the dryer 18 was 5 m. The condensing plate 30 in the dryer 18 is arranged with a predetermined inclination angle such that the downstream side in the running direction is separated from the coating film. The web initially dried by the dryer 18 was heated at 130 ° C. for 1 minute to align the discotic liquid crystalline compound. Next, UV irradiation was performed for 1 minute using a 120 W / cm high-pressure mercury lamp at 100 ° C. to polymerize the discotic liquid crystalline compound. Then, it stood to cool to room temperature. In this manner, an optical compensation sheet (KH-1) with an optically anisotropic layer was produced.
The Re retardation value of the optically anisotropic layer measured at a wavelength of 546 nm was 52 nm.

(Evaluation of tilt angle of liquid crystal compounds)
The retardation of the liquid crystal compound in the optically anisotropic layer near the alignment film and the air interface near the air interface is changed by changing the observation angle using an ellipsometer (APE-100, manufactured by Shimadzu Corporation). Jpn. J. et al. Appl. Phys. Vol. 36 (1997) p. It calculated by the method described in 143-147. The measurement wavelength was 632.8 nm. The results are shown in Table 1. The inclination angle was similarly determined for Examples 2 to 4 and Comparative Examples 1 and 2 shown below.

(Evaluation of the number of atoms on the air interface surface)
Evaluation of the number of nitrogen atoms / number of carbon atoms (N / C) and the number of fluorine atoms / number of carbon atoms (F / C) on the air interface side surface of the optically anisotropic layer was carried out by ESCA measurement (X-ray manufactured by Kratos Analytical) Evaluation was performed using a photoelectron spectrometer ESCA-3400). The results of N / C and F / C are shown in Table 1. N / C and F / C were similarly calculated for Examples 2 to 5 and Comparative Examples 2 and 3 shown below.

(Preparation of polarizing plate)
Using a polyvinyl alcohol-based adhesive, the optical compensation sheet KH-1 produced as described above was attached to one surface of a polarizer (HF-1). In addition, saponification treatment was performed on a 80 μm thick triacetyl cellulose film (TD-80U: manufactured by Fuji Photo Film Co., Ltd.), and the surface opposite to the polarizer (HF-1) using a polyvinyl alcohol-based adhesive. Pasted on.
The transmission axis of the polarizer (HF-1) and the slow axis of the polymer film (PK-1) that is the support of the optical compensation sheet were arranged in parallel. The transmission axis of the polarizer (HF-1) 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.

(Example 2)
In the preparation of the coating liquid for forming the optically anisotropic layer, the same as Example 1 except that H-15 was added instead of the exemplified compound (H-16) having a 1,3,5-triazine ring. Thus, an optical compensation sheet (KH-2) and a polarizing plate with KH-2 (HB-2) were produced. The Re retardation value of the optically anisotropic layer in the optical compensation sheet measured at a wavelength of 546 nm was 50 nm.

(Example 3)
In the preparation of the coating liquid for forming the optically anisotropic layer, the same procedure as in Example 1 was carried out except that CAB551-0.2 (manufactured by Eastman Chemical Co.) and a fluoroaliphatic group-containing polymer (P-72) were added. Thus, an optical compensation sheet (KH-3) and a polarizing plate with KH-3 (HB-3) were produced. The Re retardation value of the optically anisotropic layer in the optical compensation sheet measured at a wavelength of 546 nm was 48 nm. Moreover, when the polarizing plate was arranged in a crossed Nicol arrangement and the unevenness of the obtained optical compensation sheet was observed, no unevenness was detected even when viewed from the front and the direction inclined by 60 degrees from the normal line.

Example 4
In the preparation of the coating liquid for forming the optically anisotropic layer, the same procedure as in Example 3 was conducted except that P-11 was added instead of the exemplified compound (P-72) of the fluoroaliphatic group-containing polymer. A compensation sheet (KH-4) and a polarizing plate with KH-4 (HB-4) were produced. The Re retardation value of the optically anisotropic layer in the optical compensation sheet measured at a wavelength of 546 nm was 50 nm. Moreover, when the polarizing plate was arranged in a crossed Nicol arrangement and the unevenness of the obtained optical compensation sheet was observed, no unevenness was detected even when viewed from the front and the direction inclined by 60 degrees from the normal line.

(Example 5)
An optical compensation sheet was produced in the same manner as in Example 1 except that the heating and aging method of the optically anisotropic layer was heated in a constant temperature zone of 80 ° C. for 1 minute. The optically anisotropic layer formed a horizontal alignment, N / C on the air interface side surface was 0.04, and F / C was 0.6.

(Comparative Example 1)
An optical compensation sheet (KH-H1) was prepared in the same manner as in Example 1 except that the exemplified compound (II-1) of the general formula (1) was not added in the preparation of the coating liquid for forming the optically anisotropic layer. Furthermore, a polarizing plate (HB-H1) with KH-H1 was produced. The Re retardation value of the optically anisotropic layer in the optical compensation sheet measured at a wavelength of 546 nm was 34 nm. Further, when the polarizing plate was arranged in a crossed Nicol arrangement and the obtained optical compensation sheet was observed, light leakage was observed when viewed from the front.
(Comparative Example 2)
An optical compensation sheet (KH-H2) was prepared in the same manner as in Example 1 except that the addition amount of the exemplified compound (II-1) of the general formula (1) was changed in the preparation of the coating liquid for forming the optically anisotropic layer. Further, a polarizing plate with KH-H2 (HB-H2) was produced. The Re retardation value of the optically anisotropic layer in the optical compensation sheet measured at a wavelength of 546 nm was 30 nm.
(Comparative Example 3)
An optical compensation sheet was prepared in the same manner as in Comparative Example 1 except that the heating and aging method of the optically anisotropic layer was heated in a constant temperature zone of 80 ° C. for 1 minute. The optically anisotropic layer did not form a horizontal alignment, N / C on the air interface side surface was 0.02, and F / C was 0.
(Comparative Example 4)
Regarding the application of the coating liquid for forming the optically anisotropic layer, as a drying process that is installed immediately after the application, a hot air drying method in which the non-application surface side is supported by a roll and air is blown from the air nozzle to the application surface side to dry. An optical compensation sheet and a polarizing plate with an optical compensation sheet were produced in the same manner as in Example 1 except for the use. When the polarizing plate was arranged in a crossed Nicol arrangement and the unevenness of the obtained optical compensation sheet was observed, the unevenness was detected when viewed from the front and the direction inclined by 60 degrees from the normal line.

(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-1) were attached to the observer side and the backlight side one by one through an adhesive so that the compensation sheet (KH-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 measurement results are shown in Table 1.

  As can be seen from the results shown in Table 1, an optically anisotropic layer having an F / C of 0.5 or more and an N / C of less than 0.025 is an optically anisotropic layer having an F / C of less than 0.5. Compared to the anisotropic layer (Comparative Example 1) or the optically anisotropic layer (Comparative Example 2) having N / C of 0.025 or more, the inclination angle at the air interface is large, and the viewing angle of the liquid crystal display device is increased. A big contribution. Furthermore, Example 5 is an example in which liquid crystal molecules are aligned in a lower temperature region (constant temperature zone of 80 ° C.) than the temperature at which liquid crystal compound molecules are hybrid aligned (here, 130 ° C.). An optically anisotropic layer obtained by horizontal alignment was obtained. Therefore, when KH-1 is produced, it is presumed that the liquid crystalline molecules are horizontally aligned in the process of reaching a temperature of 130 ° C., and as a result, a defect-free hybrid alignment is formed by heat aging for 1 minute. It can be understood that KH-1 becomes an optical compensation sheet that does not leak light. On the other hand, since the optically anisotropic layer of Comparative Example 3 does not form horizontal alignment in the low temperature region (80 ° C. constant temperature zone), KH-H1 becomes an optical compensation sheet with light leakage when heated for 1 minute. I understood.

(Example 6)
Optical compensation was performed in the same manner as in Example 1 except that the polymer base material having Rth of 80, 90, 110, 120, and 130 nm was prepared by changing the amount of the retardation increasing agent used in Example 1. Sheets and further polarizing plates with optical compensation sheets were prepared. Even when the Rth of the polymer substrate was changed to 80, 90, 110, 120, and 130 nm, it was confirmed that the vertical, horizontal, and horizontal viewing angles were almost the same as the viewing angles obtained in Example 1.

(Example 7)
Example 1 except that the retardation increasing agent used in Example 1 was replaced with the following retardation increasing agent, and the addition amount of the inner layer was 1.4 parts by mass, and a polymer substrate having an Rth of 110 nm was prepared. In the same manner as described above, an optical compensation sheet and a polarizing plate with an optical compensation sheet were produced. It was confirmed that the vertical and horizontal viewing angles were almost the same as the viewing angles obtained in Example 1.

(Example 8)
Optical compensation was performed in the same manner as in Example 1 except that the polymer base material having Rth of 80, 90, 100, 120, and 130 nm was prepared by changing the addition amount of the retardation increasing agent used in Example 7. Sheets and further polarizing plates with optical compensation sheets were prepared. Even when the Rth of the polymer substrate was changed to 80, 90, 100, 120, and 130 nm, it was confirmed that the viewing angles of the top, bottom, left, and right were almost the same as the viewing angles obtained in Example 1.

It is a conceptual diagram which shows an example of the application | coating and drying line which can be utilized for preparation of the optical compensation sheet | seat of this invention. It is a conceptual diagram which shows an example of the application | coating and drying line which can be utilized for preparation of the optical compensation sheet | seat of this invention. It is a conceptual diagram which shows an example of the application | coating and drying line which can be utilized for preparation of the optical compensation sheet | seat of this invention. It is a conceptual diagram which shows an example of the application | coating and drying line which can be utilized for preparation of the optical compensation sheet | seat of this invention. It is a conceptual diagram which shows an example of the application | coating and drying line which can be utilized for preparation of the optical compensation sheet | seat of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Coating / drying line, 12 ... Strip | belt-shaped flexible support body, 14 ... Delivery apparatus, 16 ... Application | coating means, 18 ... Dryer, 20 ... Ventilation drying means, 22 ... Guide roller, 24 ... Winding device, 26 ... Dryer 30 ... Condenser plate

Claims (12)

An optical compensation sheet comprising a transparent support and an optically anisotropic layer containing a liquid crystalline compound fixed in a hybrid orientation on the support, wherein the nitrogen on the air interface side surface of the optically anisotropic layer An optical compensation sheet having an atom number / carbon atom number of less than 0.1 and a fluorine atom number / carbon atom number of 0.1 or more. The optically anisotropic layer is a layer manufactured by a method including a step of horizontally aligning molecules of a liquid crystalline compound and a step of hybrid aligning molecules of the horizontally aligned liquid crystalline compound, and the hybrid alignment is performed. At a temperature lower than the heating temperature in the process, the number of nitrogen atoms / number of carbon atoms on the air interface side surface of the optically anisotropic layer is 0.001 or more, and the number of fluorine atoms / number of carbon atoms is 0.1 or more. The optical compensation sheet according to claim 1, wherein The optical compensation sheet according to claim 1 or 2, wherein the optically anisotropic layer contains at least one compound represented by the following general formula (1):
General formula (1)
(Rf-X-) _m Ar (-W) _n
In formula (1), Ar represents an (m + n) -valent aromatic heterocyclic group or aromatic hydrocarbon ring group, X 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, n represents 1 or 2, and when m represents an integer of 2 or more, a plurality of Rf and X may be the same or different. The optical compensation sheet according to claim 1, wherein the optically anisotropic layer contains at least one compound having a triazine ring group. The optically anisotropic layer further contains at least one fluoroaliphatic polymer, and the number of fluorine atoms / number of carbon atoms on the air interface side surface of the optically anisotropic layer is 0.5 or more. 5. The optical compensation sheet according to any one of 4 above. The optical compensation sheet according to any one of claims 1 to 5, wherein the optically anisotropic layer further contains a cellulose ester. The optical compensation sheet according to claim 1, wherein the liquid crystal compound is a discotic liquid crystal compound. The optical compensation sheet according to any one of claims 1 to 7, 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. A method for producing an optical compensation sheet having at least a transparent support, an alignment film on the transparent support, and an optically anisotropic layer on the alignment film,
A composition for forming an optically anisotropic layer containing at least a liquid crystalline compound is applied on the surface of a web that is a transparent support having a surface on which an alignment film is formed. A step of performing drying while preventing turbulence of the wind in the vicinity of the coating surface and maintaining a high concentration of solvent vapor on the coating surface during drying, and horizontally aligning the molecules of the liquid crystalline compound on the surface of the alignment film. A method for producing an optical compensation sheet, comprising a step of aligning and a step of hybrid aligning molecules of the horizontally aligned liquid crystalline compound. The polarizing plate which consists of at least a polarizing film and the transparent protective film provided in the single side | surface of this polarizing film, and this transparent protective film is an optical compensation sheet of any one of Claims 1-8. At least one liquid crystal cell and a polarizing plate disposed on each side of the liquid crystal cell, and at least one of the polarizing plates is provided on a side close to the liquid crystal cell on one side of the polarizing film and the polarizing film. A liquid crystal display device comprising at least the transparent protective film, wherein the transparent protective film is the optical compensation sheet according to claim 1.

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