JP2006126768A - Optically anisotropic film, and polarizing plate using the film, and liquid crystal display - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optically anisotropic film which has proper surface smoothness and is formed from a discotic liquid-crystal compound, having uniform optical characteristics. <P>SOLUTION: This optically anisotropic film has on a support at least one optically anisotropic layer which is formed from a composition comprising the discotic liquid-crystal compound and at least one fluorine-containing polymer, having a fluoro-aliphatic group and an amido group and which has, preferably ≤10 nm Re (intra-plane retardation value) and 60-250 nm Rth (retardation value in the thickness direction), when visible light is made incident. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

The present invention relates to an optically anisotropic film and a polarizing plate useful for optical compensation of a liquid crystal display device.
The present invention also relates to a liquid crystal display device, and more particularly to a vertical alignment nematic liquid crystal display device having excellent viewing angle characteristics.

  A liquid crystal display device usually has a liquid crystal cell and a polarizing plate. The polarizing plate has a protective film and a polarizing film, and is obtained, for example, by dyeing a polarizing film made of a polyvinyl alcohol film with iodine, stretching, and laminating both surfaces with a protective film. In the transmissive liquid crystal display device, the polarizing plate is attached to both sides of the liquid crystal cell, and one or more optical compensation sheets may be disposed. In a reflective liquid crystal display device, a reflector, a liquid crystal cell, one or more optical compensation sheets, and a polarizing plate are usually arranged in this order. A liquid crystal cell usually comprises a liquid crystal molecule, two substrates for encapsulating the liquid crystal molecule, and an electrode layer for applying a voltage to the liquid crystal molecule. The liquid crystal cell performs ON / OFF display depending on the alignment state of liquid crystal molecules, and can be applied to both transmissive and reflective types. TN (Twisted Nematic), IPS (In-Plane Switching), OCB (Optically Compensatory Bend). ), VA (Vertically Aligned), and ECB (Electrically Controlled Birefringence) have been proposed.

  Among such LCDs, for applications that require high display quality, a 90 degree twisted nematic liquid crystal display device (hereinafter referred to as a TN mode) driven by thin film transistors using nematic liquid crystal molecules having positive dielectric anisotropy. ) Is mainly used. However, although the TN mode has excellent display characteristics when viewed from the front, the contrast is reduced when viewed from an oblique direction, or gradation inversion that reverses the brightness in gradation display occurs. There is a viewing angle characteristic that the display characteristic is deteriorated, and this improvement is strongly demanded.

  In recent years, as an LCD method for improving the viewing angle characteristics, nematic liquid crystal molecules having negative dielectric anisotropy are used, and the major axis of the liquid crystal molecules is aligned in a direction substantially perpendicular to the substrate without applying a voltage. A vertical alignment nematic liquid crystal display device (hereinafter referred to as VA mode) in which this is driven by a thin film transistor has been proposed (see Patent Document 1). This VA mode not only has excellent display characteristics when viewed from the front, but also exhibits a wide viewing angle characteristic by applying a viewing angle compensation phase difference film. In the VA mode, a wide viewing angle characteristic can be obtained by using two negative uniaxial retardation films having an optical axis in a direction perpendicular to the film surface, above and below the liquid crystal cell. It is also known that a wider viewing angle characteristic can be realized by using a uniaxially oriented retardation film having a positive refractive index anisotropy with a retardation value of 50 nm (see Non-Patent Document 1). . However, the use of three retardation films (see Non-Patent Document 1) not only causes an increase in production cost, but also causes a decrease in yield due to the bonding of a large number of films, and further uses a plurality of films. For this reason, there is a problem that the thickness is increased, which is disadvantageous for thinning the display device. Moreover, since an adhesive layer is used for lamination | stacking of a stretched film, an adhesive layer shrink | contracts by a temperature / humidity change, and defects, such as peeling and a curvature between films, may generate | occur | produce.

  As a method for improving these, a method of reducing the number of retardation films and a method of using a cholesteric liquid crystal layer are disclosed (see Patent Documents 2 and 3). However, even in these methods, it is necessary to bond a plurality of films, which is insufficient in terms of thinning and production cost reduction. Furthermore, there was a problem that light leakage from the oblique direction of the polarizing plate during black display was recognized, and the viewing angle was not sufficiently expanded (to the extent expected theoretically). Conventionally, an optical compensation sheet has been developed mainly assuming a small-sized or medium-sized liquid crystal display device of 15 inches or less, but recently, the luminance of a large liquid crystal display device of 17 inches or more has been improved. Development of an optical compensation sheet that contributes is desired. In a large-sized liquid crystal display device, a slight unevenness in optical characteristics that is not particularly problematic in practical use in a small-sized or medium-sized liquid crystal display device, for example, unevenness in optical characteristics due to a slight non-smoothness on the surface of an optical compensation sheet May be recognized as unevenness on the display screen. Therefore, it is necessary to further develop an optical film having an optical compensation capability corresponding to the demand for an increase in size and brightness of a liquid crystal display device. Patent Document 4 discloses an optical compensation sheet in which a discotic liquid crystal compound is fixed in a substantially horizontally aligned state, but a film having no uneven optical characteristics cannot be formed. Patent Document 5 describes that an optically anisotropic layer having high surface smoothness and high optical property uniformity can be formed by using a composition containing a leveling agent in a polymerizable liquid crystal. ing. However, depending on the type of polymerizable liquid crystal, the leveling agent may disturb the alignment of the liquid crystal. In particular, when a discotic liquid crystalline compound is used, the alignment is disturbed by the addition of the leveling agent, and the desired optical performance. It was not possible to form an optically anisotropic layer showing

Japanese Patent Laid-Open No. 2-176625 JP-A-11-95208 JP 2003-15134 A JP-A-11-352328 JP-A-11-148080 SID 97 DIGEST Pages 845-848

  An object of the present invention is to provide an optically anisotropic film having high surface smoothness and uniform optical characteristics. The present invention also provides an optically anisotropic film that contributes to optical compensation of a liquid crystal cell without causing uneven brightness when used in a liquid crystal display device, particularly a large-sized liquid crystal display device of 17 inches or more. And providing a polarizing plate. In addition, the present invention provides a liquid crystal display device in which a liquid crystal cell is accurately optically compensated and can display an image with high display quality without luminance unevenness and can be thinned, particularly a VA mode liquid crystal display. It is an object to provide an apparatus.

Means for solving the above problems are as follows.
[1] An optically anisotropic layer formed from a composition containing at least one discotic liquid crystalline compound and a fluorine-containing polymer having at least one fluoroaliphatic group and amide group on a support. An optically anisotropic film having one layer.
[2] The optically anisotropic layer film according to [1], wherein the fluorine-containing polymer includes a polymer unit derived from a fluoroaliphatic group-containing monomer and a polymer unit derived from an amide group-containing monomer.
[3] The optically anisotropic film according to [1] or [2], wherein molecules of the discotic liquid crystalline compound are substantially horizontally aligned in the optically anisotropic layer.
[4] The optically anisotropic film according to any one of [1] to [3], wherein the optically anisotropic layer has Re of 10 nm or less and Rth of 60 to 250 nm with respect to visible light.
[5] The fluoropolymer is a polymer including at least one polymer unit of a fluoroaliphatic group-containing monomer represented by the following general formula (I) or general formula (II): 4] The optically anisotropic film according to any one of the above.

［式中、Ｒ¹及びＲ²は水素原子、ハロゲン原子又はメチル基を表し、Ｌ¹及びＬ²は２価の連結基を表し、ｍ及びｎはそれぞれ独立に１以上１８以下の整数を表す。］

[Wherein, R ¹ and R ² represent a hydrogen atom, a halogen atom or a methyl group, L ¹ and L ² represent a divalent linking group, and m and n each independently represents an integer of 1 to 18. . ]

[6] The polymer according to any one of [1] to [5], wherein the fluorine-containing polymer is a polymer containing at least one polymerized unit of an amide group-containing monomer represented by the following general formula (III): Optical anisotropic film.

［式中、Ｒ³は水素原子、ハロゲン原子又はメチル基を表し、Ｒ¹⁰及びＲ¹¹はそれぞれ独立に水素原子、炭素数１〜１８のアルキル基、炭素数６〜２０の芳香族基又は炭素数１〜２０のヘテロ環基を表す。また、Ｒ¹⁰とＲ¹¹は互いに連結して複素環を形成してもよい。］

[Wherein R ³ represents a hydrogen atom, a halogen atom or a methyl group, and R ¹⁰ and R ¹¹ each independently represent a hydrogen atom, an alkyl group having 1 to 18 carbon atoms, an aromatic group having 6 to 20 carbon atoms, or carbon. The heterocyclic group of number 1-20 is represented. R ¹⁰ and R ¹¹ may be connected to each other to form a heterocyclic ring. ]

[7] The optically anisotropic film according to any one of [1] to [6], wherein the optically anisotropic layer includes at least one discotic compound different from the discotic liquid crystalline compound.
[8] The optically anisotropic film according to any one of [1] to [7], wherein the discotic liquid crystalline compound is a triphenylene liquid crystalline compound.
[9] A polarizing plate having the optically anisotropic film of any one of [1] to [8] and a polarizing film, wherein the optically anisotropic film also serves as at least one protective film of the polarizing film Board.

[10] While having a liquid crystal layer composed of a pair of substrates and liquid crystal molecules sandwiched between the two polarizing films and the two polarizing films whose absorption axes are orthogonal to each other, In a non-driven state where no external electric field is applied, the liquid crystal cell in which the liquid crystalline molecules are aligned in a direction substantially perpendicular to the substrate, optically positive refractive index anisotropy, and visible light And a liquid crystal having at least one first optically anisotropic layer having Re of 40 to 150 nm and the optically anisotropic film of any one of [1] to [8] as the second optically anisotropic layer Display device.
[11] The liquid crystal display device according to [10], wherein the optically anisotropic film also serves as at least one protective film of the two polarizing films.
[12] The liquid crystal display device according to [10] or [11], wherein the first optically anisotropic layer is a layer formed of a rod-like liquid crystalline compound or a polymer.
[13] The liquid crystal display device according to any one of [10] to [12], wherein the first optically anisotropic layer is a layer formed from a rod-like liquid crystalline compound represented by the following general formula (IV).
Formula (IV)
Q ¹ -L ¹¹ -A ¹ -L ¹³ -ML ¹⁴ -A ² -L ¹² -Q ²
[Wherein, Q ¹ and Q ² each independently represent a polymerizable group, L ¹¹ , L ¹² , L ¹³ and L ¹⁴ each independently represent a single bond or a divalent linking group, and A ¹ and A ² Each independently represents a spacer group having 2 to 20 carbon atoms, and M represents a mesogenic group. ]
[14] The first optically anisotropic layer is a layer formed from a rod-like liquid crystalline compound, and the molecules of the rod-like liquid crystalline compound in the first optically anisotropic layer are the two polarized lights. The liquid crystal display device according to any one of [10] to [13], which is fixed in a state of being horizontally aligned in a direction substantially orthogonal to one of the absorption axes of the film.
[15] The liquid crystal display device according to any one of [10] to [14], wherein the first optical anisotropic layer and the second optical anisotropic layer are disposed with a liquid crystal cell interposed therebetween.

  In the present specification, “substantially” with respect to an angle means that the angle is within a range of an exact angle of less than ± 5 °. The error from the exact angle is preferably less than 4 °, more preferably less than 3 °. Further, the “slow axis” means a direction in which the refractive index is maximized. Further, the measurement wavelength of the refractive index is a value at λ = 550 nm in the visible light region unless otherwise specified. In this specification, “visible light” means 400 nm to 700 nm, and the measurement wavelength of the refractive index is a value at λ = 550 nm in the visible light region unless otherwise specified. In this specification, “polarizing film” and “polarizing plate” are distinguished from each other, and “polarizing plate” is a laminate having a transparent protective film for protecting the polarizing film on at least one side of the “polarizing film”. Means.

  In the present invention, an optically anisotropic film having high surface smoothness and uniform optical properties is obtained by containing a fluorine-containing polymer in the optically anisotropic layer. By using this optically anisotropic film, the liquid crystal cell can be optically compensated with the same configuration as that of a conventional liquid crystal display device. The liquid crystal display device of the present invention having the optically anisotropic layer has not only display quality but also a viewing angle that is remarkably improved and a good surface shape. That is, according to the present invention, it is possible to provide a liquid crystal display device in which the liquid crystal cell is accurately optically compensated, particularly a VA mode liquid crystal display device.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, the present invention will be described in detail.
[Optically anisotropic film]
The present invention relates to a fluorine-containing composition comprising, on a support, at least one discotic liquid crystalline compound, at least one polymer unit derived from a fluoroaliphatic group-containing monomer and a polymer unit derived from an amide group-containing monomer. The present invention relates to an optically anisotropic film having at least one optically anisotropic layer formed from a composition containing a polymer.

Hereinafter, various materials and production methods used for producing the optically anisotropic film of the present invention will be described in detail.
<Fluoropolymer>
The fluorine-containing polymer used in the present invention has both a fluoroaliphatic group and an amide group. The fluorine-containing polymer preferably contains respective polymerized units derived from a fluoroaliphatic group-containing monomer and an amide group-containing monomer. The fluorine-containing polymer contributes to improving the surface smoothness of the optically anisotropic layer, and the molecules of the discotic liquid crystalline compound are substantially horizontal with respect to the layer plane (average inclination in the range of 0 to 10 °). Promotes orientation in the corners). There are no particular restrictions on the structure of the monomer containing a fluoroaliphatic group and the monomer containing an amide group constituting the polymer.

  Preferable examples of the fluorine-containing polymer that can be used in the present invention are polymers containing polymerized units of fluoroaliphatic group-containing monomers represented by the following general formula (I) or general formula (II).

In the general formula (I), R ¹ represents a hydrogen atom, a halogen atom or a methyl group, more preferably a hydrogen atom or a methyl group. L ¹ represents a divalent linking group, m represents an integer of 1 to 18, more preferably 2 to 12, still more preferably 4 to 8, and most preferably 4 or 6.

In the general formula (II), R ² represents a hydrogen atom, a halogen atom or a methyl group, and more preferably a hydrogen atom or a methyl group. L ² represents a divalent linking group, n represents an integer of 1 to 18, more preferably 2 to 12, still more preferably 4 to 8, and most preferably 4 or 6.

Next, L ¹ and L ² representing a divalent substituent will be described. L ¹ and L ² are not limited as long as they are each independently a divalent substituent, but a structure represented by the following general formula (V) is more preferable. Here, (a) shows the position bonded to the double bond side, and (b) shows the position bonded to the fluoroaliphatic group side.

General formula (V)
^{(A) -X 10 -R 20 -} (b)
In general formula (V), X ¹⁰ is a single bond, or * -COO-**, * -COS-**, * -OCO-**, * -CON (R ²¹ )-**, * -O-. Represents a divalent linking group represented by **. Here, * represents a position bonded to the double bond side, and ** represents a position bonded to R ²⁰ .
R ²⁰ is an optionally substituted polymethylene group (eg, methylene group, ethylene group, trimethylene group, etc.), an optionally substituted phenylene group (eg, o-phenylene group, m-phenylene group). , P-phenylene group, and the like, and a group that can be formed by any combination thereof. Among them, a polymethylene group is more preferable, and among the polymethylene groups, a methylene group, an ethylene group, a trimethylene group, and a tetramethylene group are preferable, and a methylene group and an ethylene group are still more preferable.
R ²¹ represents a hydrogen atom or an alkyl group which may have a substituent having 1 to 8 carbon atoms, or an aryl group which may have a substituent having 6 to 20 carbon atoms, A 1-6 alkyl group is more preferable, and a hydrogen atom or a C1-C4 alkyl group is still more preferable.

  The fluoroaliphatic group-containing monomer represented by the general formula (I) is more preferably a monomer represented by the following general formula (VI).

In General Formula (V), X ¹ represents a divalent group represented by —O—, —S—, or —N (R ²² ) —, and p represents an integer of 1 to 8. X ¹ is more preferably —O— or —N (R ²² ) —, and most preferably —O—. As for p, 1-6 are more preferable, and it is still more preferable that it is 1-3. R ¹ and m have the same meanings as described in the general formula (I), and preferred ranges are also the same. R ²² represents a hydrogen atom, an alkyl group which may have a substituent having 1 to 8 carbon atoms, or an aryl group which may have a substituent having 6 to 20 carbon atoms.

  Among the fluoroaliphatic group-containing monomers represented by the general formula (II), monomers represented by the following general formula (VII) are preferable.

In General Formula (VII), X ² represents a substituent represented by —O—, —S— or —N (R ²² ) —, and q represents an integer of 1 to 8. X ² is more preferably —O— or —N (R ²² ) —, and most preferably —O—. As for p, 1-6 are more preferable, and it is still more preferable that it is 1-3. R ² and n have the same meanings as described in the general formula (II), and the preferred ranges are also the same. R ²² has the same meaning as described in the general formula (V).

  Specific examples of the fluoroalkyl group-containing monomer represented by the general formula (I) are shown below, but are not limited thereto.

  Specific examples of the fluoroalkyl group-containing monomer represented by the general formula (II) are shown below, but are not limited thereto.

  Next, the amide group-containing monomer used in the present invention will be described. The structure of the amide group-containing monomer is not limited as long as it contains an amide group, and may contain any of primary, secondary, and tertiary amide groups. Further, the amide group may be directly bonded to the polymer main chain or may be present separately.

  A preferred example of the fluorine-containing polymer that can be used in the present invention is a polymer containing a polymerized unit of an amide group-containing monomer represented by the following general formula (III).

In general formula (III), R ³ represents a hydrogen atom, a halogen atom or a methyl group, more preferably a hydrogen atom or a methyl group. R ¹⁰ and R ¹¹ each independently represent a hydrogen atom, an alkyl group having 1 to 18 carbon atoms, an aromatic group having 6 to 20 carbon atoms or a heterocyclic group having 1 to 20 carbon atoms, and these substituents are further substituted It may have a group. In addition, an alkyl group having 1 to 12 carbon atoms and an aromatic group having 6 to 15 carbon atoms are more preferable, and an alkyl group having 1 to 6 carbon atoms and an aromatic group having 6 to 12 carbon atoms are further included. preferable. R ¹⁰ and R ¹¹ may be linked to each other to form a heterocyclic ring. Examples of the formed heterocyclic ring include a pyrrolidine ring, a piperidine ring, and a morpholine ring.

  Specific examples of the amide group-containing monomer preferably used in the present invention are shown below, but are not limited thereto.

Examples of the substituents that the monomers represented by the general formulas (I), (II), (III), (VI), and (VII) may have include the following. Hydroxyl group, halogen atom (for example, Cl, Br, F, I), cyano group, nitro group, carboxyl group, sulfo group, linear or cyclic alkyl group having 1 to 8 carbon atoms (for example, methyl, ethyl, isopropyl, n -Butyl, n-hexyl, cyclopropyl, cyclohexyl, 2-hydroxyethyl, 4-carboxybutyl, 2-methoxyethyl, 2-diethylaminoethyl), an alkenyl group having 1 to 8 carbon atoms (for example, vinyl, allyl, 2- Hexenyl), alkynyl groups having 2 to 8 carbon atoms (eg ethynyl, 1-butynyl, 3-hexynyl), aralkyl groups having 7 to 12 carbon atoms (eg benzyl, phenethyl), aryl groups having 6 to 10 carbon atoms (For example, phenyl, naphthyl, 4-carboxyphenyl, 4-acetamidophenyl, 3-methanesulfo Amidophenyl, 4-methoxyphenyl, 3-carboxyphenyl, 3,5-dicarboxyphenyl, 4-methanesulfonamidophenyl, 4-butanesulfonamidophenyl), acyl groups having 1 to 10 carbon atoms (for example, acetyl, benzoyl) , Propanoyl, butanoyl), an alkoxycarbonyl group having 2 to 10 carbon atoms (for example, methoxycarbonyl, ethoxycarbonyl), an aryloxycarbonyl group having 7 to 12 carbon atoms (for example, phenoxycarbonyl, naphthoxycarbonyl), 1 carbon atom -10 carbamoyl group (for example, unsubstituted carbamoyl, methylcarbamoyl, diethylcarbamoyl, phenylcarbamoyl), an alkoxy group having 1 to 8 carbon atoms (for example, methoxy, ethoxy, butoxy, methoxyethoxy), carbon atom An aryloxy group having 6 to 12 carbon atoms (for example, phenoxy, 4-carboxyphenoxy, 3-methylphenoxy, naphthoxy), an acyloxy group having 2 to 12 carbon atoms (for example, acetoxy, benzoyloxy), and a sulfonyloxy having 1 to 12 carbon atoms A group (for example, methylsulfonyloxy, phenylsulfonyloxy), an amino group having 0 to 10 carbon atoms (for example, unsubstituted amino, dimethylamino, diethylamino, 2-carboxyethylamino), an acylamino group having 1 to 10 carbon atoms ( Acetamide, benzamide), a sulfonylamino group having 1 to 8 carbon atoms (for example, methylsulfonylamino, phenylsulfonylamino, butylsulfonylamino, n-octylsulfonylamino), a ureido group having 1 to 10 carbon atoms (for example, ureido, Me Tilureido), urethane group having 2 to 10 carbon atoms (for example, methoxycarbonylamino, ethoxycarbonylamino), alkylthio group having 1 to 12 carbon atoms (for example, methylthio, ethylthio, octylthio), arylthio group having 6 to 12 carbon atoms (For example, phenylthio, naphthylthio), an alkylsulfonyl group having 1 to 8 carbon atoms (for example, methylsulfonyl, butylsulfonyl), an arylsulfonyl group having 7 to 12 carbon atoms (for example, phenylsulfonyl, 2-naphthylsulfonyl), the number of carbon atoms 0-8 sulfamoyl groups (eg unsubstituted sulfamoyl, methylsulfamoyl etc.), heterocyclic groups (eg 4-pyridyl, piperidino, 2-furyl, furfuryl, 2-thienyl, 2-pyrrolyl, 2-quinolylmorpholino ) Etc. In particular, preferred examples of the substituent for substituting R ¹⁰ and R ¹¹ in the general formula (III) include an aryl group, an acyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, a carbamoyl group, an alkoxy group, an aryloxy group, An acyloxy group, an acylamino group, a ureido group, a heterocyclic group, etc. are mentioned.

  The fluorine-containing polymer used in the present invention contains at least one fluoroaliphatic group-containing monomer and at least one amide group-containing monomer as polymerized units, and the polymer contains two or more types of each monomer as polymerized units. It may also be a copolymer containing one or more other copolymerizable monomers as polymerized units. Other types of such copolymerizable monomers include Polymer Handbook 2nd ed. , J .; Brandrup, Wiley lnterscience (1975) Chapter 2 Pages 1-483 can be used. Examples thereof include compounds having one addition polymerizable unsaturated bond selected from acrylic esters, methacrylic esters, methacrylamides, allyl compounds, vinyl ethers, vinyl esters and the like.

Specifically, the following monomers can be mentioned.
Acrylic esters:
Methyl acrylate, ethyl acrylate, propyl acrylate, chloroethyl acrylate, 2-hydroxyethyl acrylate, trimethylolpropane monoacrylate, benzyl acrylate, methoxybenzyl acrylate, furfuryl acrylate, tetrahydrofurfuryl acrylate, etc.
Methacrylic acid esters:
Methyl methacrylate, ethyl methacrylate, propyl methacrylate, chloroethyl methacrylate, 2-hydroxyethyl methacrylate, trimethylolpropane monomethacrylate, benzyl methacrylate, methoxybenzyl methacrylate, 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 butyrate, 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 acrylonitrile, methacrylonitrile, maleilonitrile, styrene.

  In the fluorine-containing polymer used in the present invention, the polymerization unit of the monomer having a fluoroaliphatic group is preferably 25 to 99% by mass based on the total polymerization units constituting the fluorine polymer. A more desirable ratio varies depending on the structure of the fluoroaliphatic group, and the polymerized unit of the monomer represented by the general formula (I) is preferably 50 to 99% by mass based on the total polymerized units constituting the fluoropolymer. 60 to 97% by mass, more preferably 70 to 95% by mass. The polymerization unit of the monomer represented by the general formula (II) is preferably 25 to 60% by mass, more preferably 30 to 50% by mass based on the total polymerization units constituting the fluoropolymer, More preferably, it is 35-45 mass%. Further, two or more kinds of fluoroaliphatic group-containing monomers may be contained in one polymer, and one or more monomers each represented by the general formula (I) and one represented by the general formula (II) are used. It may be included at the same time. On the other hand, the polymerization unit of the monomer having an amide group is preferably from 3 to 70% by mass, and more preferably from 5 to 60% by mass based on the total polymerization units constituting the fluoropolymer.

  The preferable mass average molecular weight of the fluorine-containing polymer used in the present invention is 2000 to 100,000, more preferably 3000 to 80,000, and still more preferably 4,000 to 60,000. Here, the mass average molecular weight and the molecular weight were converted to polystyrene by GTH analyzer using a column of TSKgel GMHxL, TSKgel G4000HxL, TSKgel G2000HxL (both trade names manufactured by Tosoh Corp.), and detection by solvent THF and differential refractometer. Is the molecular weight.

  The fluorine-containing polymer that can be used in the present invention can be produced by a known and conventional method. For example, it can be produced by adding a general-purpose radical polymerization initiator and polymerizing the above-mentioned monomer having a fluoroaliphatic group or monomer having an amide group in an organic solvent. Or depending on the case, it can manufacture by the method similar to the above by adding another addition polymerizable unsaturated compound. 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. Depending on the type of monomer used, methods such as anionic polymerization, cationic polymerization, and emulsion polymerization may be used.

  Hereinafter, although the example of the specific structure of the fluorine-containing polymer which can be used for this invention is shown, this invention is not restrict | limited at all by the following specific examples. In addition, the number in a formula shows the mass ratio of each monomer component. Mw represents a mass average molecular weight.

  In this invention, only 1 type may be used for the said fluorine-containing polymer, and 2 or more types may be used for it. The addition amount of the fluorine-containing polymer is preferably 0.01% by mass to 10% by mass, more preferably 0.05% by mass to 5% by mass with respect to the addition amount of the discotic liquid crystalline compound. More preferably, it is 0.1 mass%-3 mass%.

(Discotic compound)
Discotic 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. Soc. Chem. Comm., 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 compound includes a compound having a liquid crystallinity in which a linear alkyl group, an alkoxy group, and a substituted benzoyloxy group are radially substituted as a side chain of the mother nucleus with respect to the mother nucleus at the center of the molecule. It is. The molecule or the assembly of molecules is preferably a compound that has rotational symmetry and can give a certain orientation. In the optically anisotropic layer formed from the discotic liquid crystalline molecules, the compound finally contained in the optically anisotropic layer does not need to be a discotic liquid crystalline molecule. Also included are compounds that have a group that reacts with heat or light, and that eventually polymerize or cross-link by reaction with heat or light to increase the molecular weight and lose liquid crystallinity. Preferred examples of the discotic compound are described in JP-A-8-50206. Moreover, about superposition | polymerization of a discotic compound, Unexamined-Japanese-Patent No. 8-27284 has description.

  In order to fix the discotic compound by polymerization, it is necessary to bond a polymerizable group as a substituent to the discotic core of the discotic 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 compound having a polymerizable group is preferably a compound represented by the following formula (III).

(III) D (-LQ) n
In formula (III), D is a discotic core; L is a divalent linking group, Q is a polymerizable group, and n is an integer from 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 formula (III), the divalent linking group (L) is selected from the group consisting of an alkylene group, an alkenylene group, an arylene group, —CO—, —NH—, —O—, —S—, and combinations thereof. A divalent linking group is preferred. The divalent linking group (L) is a divalent combination of at least two divalent groups selected from the group consisting of an alkylene group, an arylene group, -CO-, -NH-, -O-, and -S-. More preferably, it is a linking group. The divalent linking group (L) is most preferably a divalent linking group in which at least two divalent groups selected from the group consisting of an alkylene group, an arylene group, -CO- and -O- are combined. . 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 to 10.

Examples of the divalent linking group (L) are shown below. The left side is bonded to the discotic core (D), and the right side is bonded to the polymerizable group (Q). AL represents an alkylene group or an alkenylene group, and AR represents an arylene group. The alkylene group, alkenylene group and arylene group may have a substituent (eg, an alkyl group).
L1: -AL-CO-O-AL-
L2: -AL-CO-O-AL-O-
L3: -AL-CO-O-AL-O-AL-
L4: -AL-CO-O-AL-O-CO-
L5: -CO-AR-O-AL-
L6: -CO-AR-O-AL-O-
L7: -CO-AR-O-AL-O-CO-
L8: -CO-NH-AL-
L9: -NH-AL-O-
L10: -NH-AL-O-CO-

L11: -O-AL-
L12: -O-AL-O-
L13: -O-AL-O-CO-
L14: -O-AL-O-CO-NH-AL-
L15: -O-AL-S-AL-
L16: -O-CO-AR-O-AL-CO-
L17: -O-CO-AR-O-AL-O-CO-
L18: -O-CO-AR-O-AL-O-AL-O-CO-
L19: -O-CO-AR-O-AL-O-AL-O-AL-O-CO-
L20: -S-AL-
L21: -S-AL-O-
L22: -S-AL-O-CO-
L23: -S-AL-S-AL-
L24: -S-AR-AL-

In the formula (III), the polymerizable group (Q) is determined according to the kind of the polymerization reaction. The polymerizable group (Q) is preferably an unsaturated polymerizable group or an epoxy group, more preferably an unsaturated polymerizable group, and most preferably an ethylenically unsaturated polymerizable group.
In the formula (III), n is an integer of 4 to 12. A specific number is determined according to the type of the disk-shaped core (D). In addition, although the combination of several L and Q may differ, it is preferable that it is the same.

  The optically anisotropic film of the present invention applies a composition containing a discotic liquid crystalline compound, a fluorine-containing polymer, and other additives onto a transparent support, and aligns the molecules of the discotic liquid crystalline compound. In addition, the optically anisotropic layer can be formed by fixing it in the orientation state. The immobilization of the discotic liquid crystalline molecules is preferably carried out 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, and a photopolymerization reaction is more preferable. Examples of the photopolymerization initiator include α-carbonyl compounds (described in US Pat. Nos. 2,367,661 and 2,367,670), acyloin ether (described in US Pat. No. 2,448,828), α-hydrocarbon substituted aromatic acyloin. Compound (described in US Pat. No. 2,722,512), polynuclear quinone compound (described in US Pat. Nos. 3,046,127 and 2,951,758), a combination of triarylimidazole dimer and p-aminophenyl ketone (US Pat. No. 3,549,367) Description), acridine and phenazine compounds (JP-A-60-105667, U.S. Pat. No. 4,239,850) and oxadiazole compounds (U.S. Pat. No. 4,212,970).

It is preferable that the usage-amount of a photoinitiator is 0.01-20 mass% of a composition (solid content of a coating liquid), and it is further more preferable that it is 0.5-5 mass%. Light irradiation for the polymerization of the liquid crystalline compound is preferably performed using ultraviolet rays. The irradiation energy is preferably ^{20mJ / cm 2 ~50J / cm 2} , further preferably 100 to 800 mJ / cm ^2. In order to accelerate the photopolymerization reaction, light irradiation may be performed under heating conditions. The thickness of the optically anisotropic layer is preferably 0.1 to 10 μm, and more preferably 0.5 to 5 μm.

  The optically anisotropic layer preferably contains at least one fluorine-containing polymer having a fluoroaliphatic group and an amide group of the present invention that contributes to horizontally aligning the molecules of the discotic liquid crystalline compound. It is more preferable to contain at least one fluorine-containing polymer containing polymerized units of a group-containing monomer and an amide group-containing monomer. In the present invention, “horizontal alignment” refers to the long axis direction of the discotic liquid crystalline compound with respect to the horizontal plane of the liquid crystal layer (for example, the surface of the support when the liquid crystal layer is formed on the support). , The disk surface of the core) is parallel, but it is not required to be strictly parallel. In the present specification, the inclination angle formed between the disk surface of the core and the horizontal plane is less than 10 degrees. Means. The inclination angle is preferably 5 degrees or less, more preferably 3 degrees or less, further preferably 2 degrees or less, and most preferably 1 degree or less. The inclination angle may be 0 degree.

(Additive to optically anisotropic layer)
The additive used together with the discotic compound can be used without particular limitation as long as it is compatible with the discotic compound and does not inhibit the orientation. For example, a plasticizer, a surfactant and a polymerizable monomer can be preferably used.
A compound that adjusts the phase transition temperature of the composition by being added to the composition containing a discotic liquid crystalline compound so that the composition can be aligned in a temperature range applied in the production process may be added as necessary. Specific examples include compounds described as an alignment temperature lowering agent in JP-A-9-104866, and among them, polymerizable monomers (eg, vinyl group, vinyloxy group, acryloyl group and methacryloyl group). Addition of the compound having).
Further, a compound capable of adjusting the phase transition temperature of a discotic liquid crystal composition without reducing optical performance like the compound described in JP-A-9-104866 is disclosed in JP-A-2001-81465. Any of the alignment temperature lowering agents disclosed herein is preferably used in the present invention. Of these, compounds (225) to (356) shown below and compounds having a discotic structure exemplified as compounds (472) to (498) shown below are more preferable, and compounds (472) to (498) are preferred. The compounds having a triphenylene skeleton exemplified in (1) are more preferred, but the present invention is not limited thereto.

(225) R: —H (226) R: —CH ₃ (227) R: — (CH ₂ ) ₂ —CH ₃ (228) R: — (CH ₂ ) ₅ —CH ₃ (229) R: — ( CH ₂ ) ₂ —O—CO—CH═CH ₂ (230) R: — (CH ₂ ) ₂ —O—CO—C (CH ₃ ) ═CH ₂ (231) R: — (CH ₂ ) ₄ —O —CO—CH═CH ₂ (232) R: —OH (233) R: —O— (CH ₂ ) ₂ —CH ₃ (234) R: —O— (CH ₂ ) ₃ —CH ₃ (235) R : —O— (CH ₂ —O—CH ₂ ) ₂ —CH ₃ (236) R: —O—CO—CH═CH ₂ (237) R: —O— (CH ₂ ) ₂ —O—CO—CH ═CH ₂ (238) R: —O—CO—C (CH ₃ ) ═CH ₂ (239) R: —O— (CH ₂ ) ₂ —O—CO—C (CH ₃ ) ═CH ₂ (240) R: -O-CO- (CH _{2 2 -O-CO-CH = CH} 2 (241) R: -O-CO- (CH 2) 2 -O-CO-C (CH 3) = CH 2

(242) R: —O— (CH ₂ ) ₄ —O—CO—CH═CH ₂

(243) R: —O— (CH ₂ ) ₄ —O—CO—CH═CH ₂

(244) R: —H (245) R: —CH ₃ (246) R: — (CH ₂ ) ₂ —CH ₃ (247) R: — (CH ₂ ) ₅ —CH ₃ (248) R: — ( CH ₂ ) ₂ —O—CO—CH═CH ₂ (249) R: — (CH ₂ ) ₂ —O—CO—C (CH ₃ ) ═CH ₂ (250) R: — (CH ₂ ) ₄ —O —CO—CH═CH ₂ (251) R: —OH (252) R: —O— (CH ₂ ) ₂ —CH ₃ (253) R: —O— (CH ₂ ) ₃ —CH ₃ (254) R : —O— (CH ₂ —O—CH ₂ ) ₂ —CH ₃ (255) R: —O—CO—CH═CH ₂ (256) R: —O— (CH ₂ ) ₂ —O—CO—CH ═CH ₂ (257) R: —O—CO—C (CH ₃ ) ═CH ₂ (258) R: —O— (CH ₂ ) ₂ —O—CO—C (CH ₃ ) ═CH ₂ (259) R: -O-CO- (CH _{2 2 -O-CO-CH = CH} 2 (260) R: -O-CO- (CH 2) 2 -O-CO-C (CH 3) = CH 2

(261) R: —O— (CH ₂ ) ₄ —O—CO—CH═CH ₂

(262) R: —O— (CH ₂ ) ₄ —O—CO—CH═CH ₂

(263) R: —H (264) R: —CH ₃ (265) R: — (CH ₂ ) ₂ —CH ₃ (266) R: — (CH ₂ ) ₅ —CH ₃ (267) R: — ( CH ₂ ) ₂ —O—CO—CH═CH ₂ (268) R: — (CH ₂ ) ₂ —O—CO—C (CH ₃ ) ═CH ₂ (269) R: — (CH ₂ ) ₄ —O —CO—CH═CH ₂ (270) R: —OH (271) R: —O— (CH ₂ ) ₂ —CH ₃ (272) R: —O— (CH ₂ ) ₃ —CH ₃ (273) R : —O— (CH ₂ —O—CH ₂ ) ₂ —CH ₃ (274) R: —O—CO—CH═CH ₂ (275) R: —O— (CH ₂ ) ₂ —O—CO—CH ═CH ₂ (276) R: —O—CO—C (CH ₃ ) ═CH ₂ (277) R: —O— (CH ₂ ) ₂ —O—CO—C (CH ₃ ) ═CH ₂ (278) R: -O-CO- (CH _{2 2 -O-CO-CH = CH} 2 (279) R: -O-CO- (CH 2) 2 -O-CO-C (CH 3) = CH 2

(280) R: —O— (CH ₂ ) ₄ —O—CO—CH═CH ₂

(281) R: —O— (CH ₂ ) ₄ —O—CO—CH═CH ₂

(282) R: —H (283) R: —CH ₃ (284) R: — (CH ₂ ) ₂ —CH ₃ (285) R: — (CH ₂ ) ₅ —CH ₃ (286) R: — ( _{CH 2) 2 -O-CO-} CH = CH 2 (287) R :-( CH 2) 2 -O-CO-C (CH 3) = CH 2 (288) R :-( CH 2) 4 -O —CO—CH═CH ₂ (289) R: —OH (290) R: —O— (CH ₂ ) ₂ —CH ₃ (291) R: —O— (CH ₂ ) ₃ —CH ₃ (292) R : —O— (CH ₂ —O—CH ₂ ) ₂ —CH ₃ (293) R: —O—CO—CH═CH ₂ (294) R: —O— (CH ₂ ) ₂ —O—CO—CH ═CH ₂ (295) R: —O—CO—C (CH ₃ ) ═CH ₂ (296) R: —O— (CH ₂ ) ₂ —O—CO—C (CH ₃ ) ═CH ₂ (297) R: -O-CO- (CH _{2 2 -O-CO-CH = CH} 2 (298) R: -O-CO- (CH 2) 2 -O-CO-C (CH 3) = CH 2

(299) R: —O— (CH ₂ ) ₄ —O—CO—CH═CH ₂

(300) R: —O— (CH ₂ ) ₄ —O—CO—CH═CH ₂

(301) R: —H (302) R: —CH ₃ (303) R: — (CH ₂ ) ₂ —CH ₃ (304) R: — (CH ₂ ) ₅ —CH ₃ (305) R: — ( _{CH 2) 2 -O-CO-} CH = CH 2 (306) R :-( CH 2) 2 -O-CO-C (CH 3) = CH 2 (307) R :-( CH 2) 4 -O —CO—CH═CH ₂ (308) R: —OH (309) R: —O— (CH ₂ ) ₂ —CH ₃ (310) R: —O— (CH ₂ ) ₃ —CH ₃ (311) R : —O— (CH ₂ —O—CH ₂ ) ₂ —CH ₃ (312) R: —O—CO—CH═CH ₂ (313) R: —O— (CH ₂ ) ₂ —O—CO—CH ═CH ₂ (314) R: —O—CO—C (CH ₃ ) ═CH ₂ (315) R: —O— (CH ₂ ) ₂ —O—CO—C (CH ₃ ) ═CH ₂ (316) R: -O-CO- (CH _{2 2 -O-CO-CH = CH} 2 (317) R: -O-CO- (CH 2) 2 -O-CO-C (CH 3) = CH 2

(318) R: —O— (CH ₂ ) ₄ —O—CO—CH═CH ₂

(319) R: —O— (CH ₂ ) ₄ —O—CO—CH═CH ₂

(320) R: —H (321) R: —CH ₃ (322) R: — (CH ₂ ) ₂ —CH ₃ (323) R: — (CH ₂ ) ₅ —CH ₃ (324) R: — ( _{CH 2) 2 -O-CO-} CH = CH 2 (325) R :-( CH 2) 2 -O-CO-C (CH 3) = CH 2 (326) R :-( CH 2) 4 -O —CO—CH═CH ₂ (327) R: —OH (328) R: —O— (CH ₂ ) ₂ —CH ₃ (329) R: —O— (CH ₂ ) ₃ —CH ₃ (330) R : —O— (CH ₂ —O—CH ₂ ) ₂ —CH ₃ (331) R: —O—CO—CH═CH ₂ (332) R: —O— (CH ₂ ) ₂ —O—CO—CH ═CH ₂ (333) R: —O—CO—C (CH ₃ ) ═CH ₂ (334) R: —O— (CH ₂ ) ₂ —O—CO—C (CH ₃ ) ═CH ₂ (335) R: -O-CO- (CH _{2 2 -O-CO-CH = CH} 2 (336) R: -O-CO- (CH 2) 2 -O-CO-C (CH 3) = CH 2

(337) R: —O— (CH ₂ ) ₄ —O—CO—CH═CH ₂

(338) R: —O— (CH ₂ ) ₄ —O—CO—CH═CH ₂

(339) R: —C≡C—H (340) R: —C≡C—CH ₃ (341) R: —C≡C— (CH ₂ ) ₂ —CH ₃ (342) R: —C≡C — (CH ₂ ) ₅ —CH ₃ (343) R: —C≡C— (CH ₂ ) ₂ —O—CO—CH═CH ₂ (344) R: —C≡C— (CH ₂ ) ₂ —O —CO—C (CH ₃ ) ═CH ₂ (345) R: —C≡C— (CH ₂ ) ₄ —O—CO—CH═CH ₂ (346) R: —C≡C—OH (347) R : —C≡C—O— (CH ₂ ) ₂ —CH ₃ (348) R: —C≡C—O— (CH ₂ ) ₃ —CH ₃ (349) R: —C≡C—O— (CH _2— O—CH ₂ ) ₂ —CH ₃ (350) R: —C≡C—O—CO—CH═CH ₂ (351) R: —C≡C—O— (CH ₂ ) ₂ —O—CO _{-CH = CH 2 (352) R} : -C≡C-O-CO-C (C _{3) = CH 2 (353)} R: -C≡C-O- (CH 2) 2 -O-CO-C (CH 3) = CH 2 (354) R: -C≡C-O-CO- ( CH ₂ ) ₂ —O—CO—CH═CH ₂ (355) R: —C≡C—O—CO— (CH ₂ ) ₂ —O—CO—C (CH ₃ ) ═CH ₂

(356) R: —O— (CH ₂ ) ₄ —O—CO—CH═CH ₂

(472) R: —OH (473) R: —O— (CH ₂ ) ₂ —CH ₃ (474) R: —O— (CH ₂ ) ₃ —CH ₃ (475) R: —O— (CH ₂ —O—CH ₂ ) ₂ —CH ₃ (476) R: —O—CO—CH═CH ₂ (477) R: —O— (CH ₂ ) ₂ —O—CO—CH═CH ₂ (478) R : —O—CO—C (CH ₃ ) ═CH ₂ (479) R: —O— (CH ₂ ) ₂ —O—CO—C (CH ₃ ) ═CH ₂ (480) R: —O—CO— (CH ₂ ) ₂ —O—CO—CH═CH ₂ (481) R: —O—CO— (CH ₂ ) ₂ —O—CO—C (CH ₃ ) ═CH ₂ (482) R: —C≡ C—C (CH ₃ ) ₂ —OH (483) R: —C≡C—Si (CH ₃ ) ₃ (484) R: —C≡C— (CH ₂ ) ₂ —CH ₃ (485) R: — _{C≡C- (CH 2) 2 -O-} CO-C _{= CH 2 (486) R:} -CH = CH- (CH 2) 2 -CH 3 (487) R: -CH = CH- (CH 2) 2 -O-CO-CH = CH 2

(488) R: —O—CO—CH═CH ₂

(489) R: —O—CO—CH═CH ₂

(490) R: —H (491) R: —O— (CH ₂ ) ₂ —CH ₃ (492) R: —O— (CH ₂ ) ₂ —O—CO—CH═CH ₂

(493) R: -H (494 ) R: -O- (CH 2) 2 -CH 3 (495) R: -O- (CH 2) 2 -O-CO-CH = CH 2

(496) R: —H (497) R: —O— (CH ₂ ) ₂ —CH ₃ (498) R: —O— (CH ₂ ) ₂ —O—CO—CH═CH ₂

  The amount of the compound capable of adjusting the phase transition temperature, preferably a discotic compound, is generally in the range of 1 to 50% by mass and in the range of 2 to 40% by mass with respect to the discotic liquid crystalline compound. It is more preferable that it is in the range of 3 to 30% by mass.

  In addition, when a monomer having 4 or more polymerizable reactive functional groups is mixed and used, adhesion between the alignment film and the optically anisotropic layer can be improved.

  The optically anisotropic layer is preferably formed by applying a coating liquid containing a liquid crystalline compound, a fluorine-containing polymer, the above polymerization initiator and other additives onto the alignment film. 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, toluene, hexane), alkyl halides (eg, , Chloroform, dichloromethane), 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. The coating liquid can be applied by a known method (eg, extrusion coating method, direct gravure coating method, reverse gravure coating method, die coating method).

  In order to align the molecules of the discotic liquid crystalline compound, it is preferable to use an alignment film. The alignment film may be an organic compound (preferably polymer) rubbing treatment, oblique deposition of an inorganic compound, formation of a layer having a microgroup, or an organic compound (eg, ω-triconic acid) by the Langmuir-Blodgett method (LB film). , Dioctadecyldimethylammonium chloride, methyl stearylate, etc.). Furthermore, an alignment film in which an alignment function is generated by application of an electric field, application of a magnetic field, or light irradiation is also known. An alignment film formed by a polymer rubbing treatment is particularly preferred. The rubbing process is carried out by rubbing the surface of the polymer layer several times in a certain direction with paper or cloth.

The type of polymer used for the alignment film can be determined according to the alignment (particularly the average tilt angle) of the liquid crystal compound. For example, in order to align the liquid crystalline compound horizontally, a polymer (ordinary alignment polymer) that does not decrease the surface energy of the alignment film is used. Specific types of polymers are described in various documents about liquid crystal cells or optical compensation sheets. In particular, in the present invention, when the liquid crystalline compound is aligned in a direction orthogonal to the rubbing treatment direction, the modified polyvinyl alcohol described in JP-A No. 2002-62427 and JP-A No. 2002-98836 are described. Acrylic acid-based copolymers, polyimides described in JP-A No. 2002-268068, and polyamic acid can be preferably used. Any of the alignment films preferably has a polymerizable group for the purpose of improving the adhesion between the liquid crystal compound and the transparent support. The polymerizable group can be introduced by introducing a repeating unit having a polymerizable group in the side chain or as a substituent of a cyclic group. It is more preferable to use an alignment film that forms a chemical bond with the liquid crystal compound at the interface. Such an alignment film is described in JP-A-9-152509. The thickness of the alignment film is preferably 0.01 to 5 μm, and more preferably 0.05 to 2 μm.
In addition, after aligning a liquid crystalline compound using an alignment film, the liquid crystalline compound is fixed in the aligned state to form an optically anisotropic layer, and only the optically anisotropic layer is a polymer film (or transparent support) It may be transferred onto the body).

There is no restriction | limiting in particular about the optical characteristic of the said optically anisotropic layer, It determines according to a use. When used as a second optically anisotropic layer in a VA mode liquid crystal display device to be described later, it is preferable that Re be 10 nm or less and Rth be 60 to 250 nm. Re and Rth can be adjusted by selecting various materials used for forming the optically anisotropic layer, controlling the alignment state of the liquid crystalline compound, and selecting the thickness of the layer. In the present specification, Re and Rth represent in-plane retardation and retardation in the thickness direction at a wavelength λ, respectively. In the present invention, Re is a value measured using KOBRA 21ADH (manufactured by Oji Scientific Instruments) with light having a wavelength of λ nm incident in the normal direction of the film. Rth was measured by making light having a wavelength of λ nm incident from a direction inclined + 40 ° with respect to the film normal direction with the Re and slow axis (determined by KOBRA 21ADH) as the tilt axis (rotation axis). Measured in three directions: retardation value and retardation value measured by making light of wavelength λ nm incident from a direction inclined by -40 ° with respect to the film normal direction with the slow axis as the tilt axis (rotation axis) The value calculated by KOBRA 21ADH based on the retardation value obtained. Here, as the assumed value of the average refractive index, the values in the polymer handbook (JOHN WILEY & SONS, INC) and catalogs of various optical films can be used. Those whose average refractive index is not known can be measured with an Abbe refractometer. The average refractive index values of main optical films are exemplified below: cellulose acylate (1.48), cycloolefin polymer (1.52), polycarbonate (1.59), polymethyl methacrylate (1.49), Polystyrene (1.59).
The KOBRA 21ADH calculates nx, ny, and nz by inputting the assumed value of the average refractive index and the film thickness.

The optically anisotropic film of the present invention has a support. The support is preferably transparent, and specifically, a support having a light transmittance of 80% or more is preferably used. The transparent support is preferably a polymer film having small wavelength dispersion, and specifically, the ratio of Re (400 nm) / Re (700 nm) is preferably less than 1.2. The transparent support also preferably has a small optical anisotropy. Specifically, the in-plane retardation (Re) is preferably 20 nm or less, and more preferably 10 nm or less. An alignment film and an optically anisotropic layer can also be formed continuously on a long transparent support. The long transparent support has a roll-like or rectangular sheet-like shape. It is preferable to laminate the optically anisotropic layer using a roll-shaped transparent support and then cut it into a required size. Examples of the polymer include cellulose ester, polycarbonate, polysulfone, polyethersulfone, polyacrylate and polymethacrylate. Cellulose acylate is preferred, acetyl cellulose is more preferred, and triacetyl cellulose is most preferred. Also, polyolefins such as ZEONEX, ZEONOR (both manufactured by Nippon Zeon Co., Ltd.), and ARTON (manufactured by JSR Co., Ltd.) are preferably used for optical reasons as described later in the description of polarizing plates. it can. These supports preferably used in the present invention include, in addition to the optical anisotropic film support according to claim 1, other optical anisotropic layers and optical films included in the liquid crystal display device of the present invention. It can also be preferably used as a support.
About manufacturing a cellulose acylate film using a non-chlorinated solvent, it is described in detail in JIII Journal of Technical Disclosure No. 2001-1745, and the cellulose acylate film described therein is also preferably used in the present invention. it can. The polymer film is preferably formed by a solvent cast method. The thickness of the transparent support is preferably 20 to 500 μm, and more preferably 50 to 200 μm. In order to improve adhesion between the transparent support and the layer (adhesive layer, vertical alignment film or optically anisotropic layer) provided on the transparent support, surface treatment (eg, glow discharge treatment, corona discharge treatment, ultraviolet ray) is applied to the transparent support. (UV) treatment, flame treatment) may be performed. An adhesive layer (undercoat layer) may be provided on the transparent support.

  The optically anisotropic film of the present invention can be used for various applications. The optically anisotropic film of the present invention is useful as an optical compensation sheet for liquid crystal cells driven in various modes. In particular, it is possible to accurately optically compensate a VA mode liquid crystal cell. Moreover, it can incorporate in a liquid crystal display device as a member integrated with the polarizing film, and in such a case, the optically anisotropic film of the present invention may also serve as a protective film for the polarizing film.

Next, the polarizing plate of the present invention will be described.
[Polarizer]
The polarizing plate of the present invention has at least the polarizing film and the optically anisotropic film of the present invention. The polarizing film that can be used in the present invention is not particularly limited, and conventionally known polarizing films can be used. For example, films made of hydrophilic polymers such as polyvinyl alcohol, partially formalized polyvinyl alcohol, partially saponified ethylene / vinyl acetate copolymer, dichroic dyes such as iodine and / or azo, anthraquinone and tetrazine A material obtained by adsorbing a dichroic material composed of the above material and subjecting it to stretching and orientation can be used. In this invention, it is preferable to use the extending | stretching method of Unexamined-Japanese-Patent No. 2002-131548.

  Both surfaces of the polarizing film are preferably protected with a transparent protective film (also referred to as “protective film”), and the protective film on at least one of the surfaces is preferably the optically anisotropic film of the present invention. The type of the transparent protective film on the other surface is not particularly limited, and cellulose esters such as cellulose acetate, cellulose acetate butyrate, and cellulose propionate, polycarbonate, polyolefin, polystyrene, polyester, and the like can be used. The retardation of the transparent protective film is, for example, preferably 10 nm or less at 632.8 nm, and more preferably 5 nm or less. From the viewpoint of such low retardation, polyolefins such as cellulose triacetate, ZEONEX, ZEONOR (both manufactured by Nippon Zeon Co., Ltd.), and ARTON (manufactured by JSR Co., Ltd.) are preferably used as the transparent protective film. It is done. Other examples include non-birefringent optical resin materials as described in JP-A-8-110402 or JP-A-11-293116. When cellulose acetate is used for the transparent protective film, the retardation is preferably less than 3 nm, and more preferably 2 nm or less, for the purpose of reducing the change in retardation due to environmental temperature and humidity. The cellulose acylate film described in the above-mentioned Invention Association Open Technical Report 2001-1745 can also be preferably used.

  In the present invention, it is preferable that one of the protective films of the polarizing film also serves as the optically anisotropic film of the present invention for the purpose of reducing the thickness. When producing the polarizing plate of this aspect, the support body of an optically anisotropic film is adhere | attached on the surface of a polarizing film. The optically anisotropic film and the polarizing film are preferably subjected to fixing treatment from the viewpoint of preventing the optical axis from shifting and preventing foreign matters such as dust from entering. An appropriate method such as an adhesive method through a transparent adhesive layer can be applied to the fixed lamination. There is no particular limitation on the type of the adhesive and the like, and from the viewpoint of preventing changes in the optical properties of the constituent members, those that do not require a high-temperature process during curing or drying are preferable, and a long-time curing process is preferable. And those that do not require drying time. From such a viewpoint, a hydrophilic polymer adhesive or a pressure-sensitive adhesive layer is preferably used. For the formation of the pressure-sensitive adhesive layer, for example, a transparent pressure-sensitive adhesive using an appropriate polymer such as an acrylic polymer, a silicone-based polymer, polyester, polyurethane, polyether, or synthetic rubber can be used. Among these, acrylic pressure-sensitive adhesives are preferred from the viewpoints of optical transparency, adhesive properties, weather resistance, and the like. In addition, an adhesion layer can also be provided as needed on one side or both sides of a polarizing plate for the purpose of adhesion to an adherend such as a liquid crystal cell. In that case, when the pressure-sensitive adhesive layer is exposed on the surface, it is preferable to temporarily attach a separator or the like to prevent contamination of the pressure-sensitive adhesive layer surface until it is put to practical use.

  Appropriate functions such as a protective film for various purposes such as water resistance in accordance with the above-mentioned transparent protective film, an antireflection layer and / or an antiglare treatment layer for the purpose of preventing surface reflection, etc. on one or both sides of the polarizing film You may use the polarizing plate in which the layer was formed. The antireflection layer can be suitably formed, for example, as a light interference film such as a fluorine polymer coating layer or a multilayer metal vapor deposition film. The antiglare layer is also formed by an appropriate method that diffuses the surface reflected light, for example, by providing a fine uneven structure on the surface by an appropriate method such as a resin coating layer containing fine particles, embossing, sandblasting or etching. can do. Examples of the fine particles include inorganic materials having an average particle diameter of 0.5 to 20 μm, such as silica, calcium oxide, alumina, titania, zirconia, tin oxide, indium oxide, cadmium oxide, and antimony oxide. One type or two or more types of fine particles, or crosslinked or uncrosslinked organic fine particles made of a suitable polymer such as polymethyl methacrylate or polyurethane can be used. The above-mentioned adhesive layer or pressure-sensitive adhesive layer may contain such fine particles and exhibit light diffusibility.

The polarizing plate of the present invention preferably has optical properties and durability (storability in short and long term) equivalent to or higher than those of commercially available super high contrast products (for example, HLC2-5618 manufactured by Sanlitz Co., Ltd.). Specifically, the visible light transmittance is 42.5% or more, and the degree of polarization ({(Tp−Tc) / (Tp + Tc)} ^1/2 ≧ 0.9995 (where Tp is parallel transmittance and Tc is orthogonal) The change rate of the light transmittance before and after leaving for 500 hours in a 60 ° C., 90% humidity RH atmosphere and 500 ° C. in a dry atmosphere for 500 hours is 3% based on the absolute value. In the following, it is further preferable that the change rate of the polarization degree is 1% or less, further 0.1% or less based on the absolute value.

Next, a liquid crystal display device using the optically anisotropic film of the present invention or the polarizing plate of the present invention will be described.
[Liquid Crystal Display]
First, an embodiment of the liquid crystal display device of the present invention will be described with reference to the drawings. FIG. 1 is a schematic view showing an example of the configuration of a liquid crystal display device of the present invention, and FIG. 2 is a configuration of a polarizing plate usable in the present invention. In FIG. 1, an example in which active driving is performed using a nematic liquid crystal having negative dielectric anisotropy as a field effect liquid crystal will be described.

  In FIG. 1, the liquid crystal display device includes a liquid crystal cell (5 to 8) and a pair of polarizing plates 1 and 12 disposed on both sides of the liquid crystal cell. A first optically anisotropic layer 3 is provided between the polarizing plate 1 and the liquid crystal cells 5 to 8, and a second optically anisotropic layer 10 is provided between the polarizing plate 12 and the liquid crystal cells 5 to 8. Is arranged. The liquid crystal cell includes an upper electrode substrate 5, a lower electrode substrate 8, and liquid crystal molecules 7 sandwiched between them. The liquid crystal molecules 7 are aligned in a direction substantially perpendicular to the substrate in a non-driven state where no external electric field is applied, by the rubbing treatment directions 6 and 9 applied to the opposing surfaces of the electrode substrates 5 and 8. Is controlled to do. The upper polarizing plate 1 and the lower polarizing plate 12 are laminated so that the absorption axis 2 and the absorption axis 13 are substantially orthogonal.

  As shown in FIG. 2, the polarizing plates 1 and 12 include a polarizing film 103 sandwiched between protective films 101 and 105. The polarizing plates 1 and 12 can be produced by, for example, dyeing a polarizing film made of a polyvinyl alcohol film with iodine and performing stretching to obtain the polarizing film 103 and laminating protective films 101 and 105 on both sides thereof. it can. In the case of lamination, it is preferable in terms of productivity to bond a total of three films of a pair of protective film and polarizing film with a roll, a TO, and a roll. In addition, as shown in FIG. 2, the roll, TO, and roll can be easily laminated so that the slow axes 102 and 106 of the protective films 101 and 105 and the absorption axis 104 of the polarizing film 103 are parallel to each other. It is preferable because the polarizing plate has a high mechanical stability in which the dimensional change and curling of the polarizing plate hardly occur. The same effect can be obtained if at least two axes of the three films, for example, the slow axis of one protective film and the absorption axis of the polarizing film, or the slow axes of the two protective films are substantially parallel. can get.

  In FIG. 1 again, the first optical anisotropic layer 3 has an optically positive refractive index anisotropy, and has a retardation (Re) of 40 to 150 nm with respect to visible light. The material constituting the first optically anisotropic layer 3 is not particularly limited, and may be a layer formed from a liquid crystal compound or a layer formed from a polymer film. A layer formed from a compound is preferred. On the other hand, the second optically anisotropic layer 10 has an optically negative refractive index anisotropy, Re is 10 nm or less and Rth is 60 to 250 nm with respect to visible light. The second optically anisotropic layer 10 is composed of the optically anisotropic film of the present invention, that is, an optically anisotropic layer formed from a composition containing a discotic liquid crystalline compound and the fluoropolymer. Have at least one layer. These optically anisotropic layers 3 and 10 eliminate the image coloring of the liquid crystal cell and contribute to the expansion of the viewing angle.

  In FIG. 1, when the upper side is the observer side, in FIG. 1, the first optical anisotropic layer 3 is placed between the observer-side polarizing plate 1 and the observer-side liquid crystal cell substrate 5 in the second state. Although the configuration in which the optically anisotropic layer 10 is disposed between the back-side polarizing plate 12 and the back-side liquid crystal cell substrate 8 is shown, the first optically anisotropic layer and the second optical anisotropy are shown. The layers may be replaced, and both the first and second optical anisotropic layers are arranged between the polarizing plate 1 on the viewer side and the substrate 5 for the viewer side liquid crystal cell. Or may be disposed between the polarizing plate 12 on the back side and the substrate 8 for the back side liquid crystal cell. Further, the first optically anisotropic layer 3 may be integrated with the polarizing plate 1 and can be incorporated in the liquid crystal display device in an integrated state with the polarizing plate 1. When the first optically anisotropic layer is a layer formed from a rod-like liquid crystalline compound, the optically anisotropic layer is usually formed on a support. For example, the first optically anisotropic layer May be made to function as a protective film on one side of the polarizing film, in the order of a transparent protective film, a polarizing film, a transparent protective film (also used as a transparent support), and the first optical anisotropic layer. A laminated integrated polarizing plate is preferable. When the integrated polarizing plate is incorporated in a liquid crystal display device, a transparent protective film, a polarizing film, a transparent protective film (also a transparent support), and a first optical anisotropic material are arranged from the outside of the device (the side far from the liquid crystal cell). It is preferable to incorporate them in the order of the active layers. Furthermore, when the first optical anisotropic layer 3 is a polymer film, the first optical anisotropic layer 3 may be one protective film of the polarizing plate 1. In this embodiment, the integrated polarizing plate is laminated in the order of the transparent protective film, the polarizing film, and the first optically anisotropic layer (also serving as the transparent protective film), and the integrated polarizing plate is disposed outside (distant from the liquid crystal cell). It is preferable that the transparent protective film, the polarizing film, and the first optical anisotropic layer (also known as the transparent protective film) are incorporated in the liquid crystal display device from the side.

  The same applies to the second optically anisotropic layer 10 and can be incorporated in the liquid crystal display device as an integrated polarizing plate integrated with the polarizing plate 12, and one protective film of the polarizing plate 12 is the second optical film. It may also serve as a transparent support for the anisotropic layer 10. In such an embodiment, the integrated polarizing plate is laminated in the order of a transparent protective film, a polarizing film, a transparent protective film (also used as a transparent support), and a second optically anisotropic layer. It is preferable to incorporate it into the liquid crystal display device in the order of the transparent protective film, the polarizing film, the transparent protective film (also a transparent support), and the second optically anisotropic layer from the side far from the liquid crystal cell.

  In particular, as in FIG. 1, it is preferable that the first optical anisotropic layer and the second optical anisotropic layer are arranged with a liquid crystal cell interposed therebetween.

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

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

<< VA mode liquid crystal cell >>
In the present invention, the liquid crystal cell is preferably in the VA mode. The VA mode liquid crystal cell is formed by sealing liquid crystal molecules having negative dielectric anisotropy between upper and lower substrates whose opposite surfaces are rubbed. For example, by using liquid crystal molecules having Δn = 0.0813 and Δε = −4.6, a director indicating the alignment direction of the liquid crystal molecules, that is, a liquid crystal cell having a so-called tilt angle of about 89 ° can be manufactured. At this time, the thickness d of the liquid crystal layer can be about 3.5 μm. The brightness at the time of white display changes according to the magnitude of the product Δnd of the thickness d of the liquid crystal layer and the refractive index anisotropy Δn. In order to obtain the maximum brightness, the thickness d of the liquid crystal layer is preferably in the range of 0.2 to 0.5 μm.

  A transparent electrode (not shown) is formed inside each alignment film (not shown) of the substrate 5 and the substrate 8, but the liquid crystal in the liquid crystal layer is in a non-driving state where no driving voltage is applied to the electrodes. The molecules 7 are aligned substantially perpendicular to the substrate surface, and as a result, the polarization state of the light passing through the liquid crystal panel hardly changes. As described above, since the absorption axis 2 of the upper polarizing plate 1 of the liquid crystal cell and the absorption axis 13 of the lower polarizing plate 12 are substantially orthogonal to each other, light does not pass through the polarizing plate. In the liquid crystal display device, an ideal black display is realized in a non-driven state. On the other hand, in the driving state, the liquid crystal molecules are inclined in a direction parallel to the substrate surface, and the light passing through the liquid crystal panel changes the polarization state by the inclined liquid crystal molecules and passes through the polarizing plate. In other words, the liquid crystal display device of FIG. 1 can obtain white display in the driving state.

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

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

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

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

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

  In the present invention, the second optically anisotropic layer is composed of the optically anisotropic film of the present invention. The raw material of the first optically anisotropic layer is not particularly limited, but may be formed from a composition containing a liquid crystal compound. An optically anisotropic layer having optical anisotropy expressed by the orientation of liquid crystalline molecules can realize optical properties that cannot be obtained by a conventional stretched birefringent polymer film. In particular, a combination of a first optically anisotropic layer formed from a composition containing a rod-like liquid crystal compound and a second optically anisotropic layer formed from a composition containing a discotic liquid crystalline compound provides a liquid crystal The optical characteristics of the display device can be significantly improved. In the present invention, an optically anisotropic layer formed from a liquid crystalline compound and an optically anisotropic layer formed from a composition containing a liquid crystalline compound are expressed by molecular orientation of the liquid crystalline compound. A layer exhibiting optical anisotropy, which is not only a liquid crystalline compound but also a material that contributes to controlling the alignment of liquid crystalline molecules, and is necessary for fixing the liquid crystalline molecules in an aligned state. Materials and the like may be included. Further, the liquid crystalline molecules may lose liquid crystallinity after being fixed in the alignment state.

  In the present invention, the in-plane retardation (Re) of the first optical anisotropic layer is 40 to 150 nm, the Re of the second optical anisotropic layer is 10 nm or less, and the Rth is 60 to 250 nm. Since the first and second optically anisotropic layers have an optical compensation function as a whole when combined, it is more preferable to adjust the combined overall retardation. When the first and second optically anisotropic layers are combined, it is preferable that Re as a whole is 30 to 200 nm and Rth is 60 to 500 nm.

  The first optically anisotropic layer used in the present invention is preferably formed from a composition containing a rod-like liquid crystalline compound, and Re is 40 to 150 nm, preferably 50 to 120 nm with respect to visible light. is there. The rod-like liquid crystalline compound preferably has a polymerizable group. In the case of a rod-like liquid crystal compound having a polymerizable group, it is preferably fixed in a substantially horizontal (homogeneous) orientation. Substantially horizontal means that the average angle (average inclination angle) between the major axis direction of the rod-like liquid crystalline compound and the surface of the optically anisotropic layer is in the range of 0 ° to 10 °. The rod-like liquid crystal compound may be obliquely aligned. Even in the case of oblique alignment, the average inclination angle is preferably 0 ° to 20 °.

  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. In addition to the above low-molecular liquid crystalline molecules, high-molecular liquid crystalline molecules can also be used. The rod-like liquid crystalline compound having a low molecular polymerizable group that is particularly preferably used is a rod-like liquid crystalline compound of the following general formula (IV).

Formula (IV)
Q ¹ -L ¹¹ -A ¹ -L ¹³ -ML ¹⁴ -A ² -L ¹² -Q ²
In the formula, Q ¹ and Q ² each independently represent a polymerizable group, L ¹¹ , L ¹² , L ¹³ and L ¹⁴ are each independently a single bond or a divalent linking group, and A ¹ and A ² are A spacer group having 2 to 20 carbon atoms is represented, and M represents a mesogenic group.

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

L ¹¹ , L ¹² , L ¹³ and L ¹⁴ each independently represents a single bond or a divalent linking group, and represents —O—, —S—, —CO—, —NR ³¹ —, —CO—O—. , -O-CO-O -, - CO-NR 31 -, - NR 31 -CO -, - O-CO -, - O-CO-NR 31 -, - NR 31 -CO-O -, - NR 31 A divalent linking group selected from the group consisting of —CO—NR ³¹ — or a single bond is preferable. R ³¹ is an alkyl group having 1 to 7 carbon atoms or a hydrogen atom. L ¹³ and L ¹⁴ are each preferably —O— or —O—CO—O—.

Of the groups represented by the combination of Q ¹ and L ¹¹ or Q ² and L ¹² , CH ₂ ═CH—CO—O—, CH ₂ ═C (CH ₃ ) —CO—O—, and CH ₂ ═C (Cl) —CO—O— is preferred, and CH ₂ ═CH—CO—O— is most preferred.

A ¹ and A ² represent a spacer group having 2 to 20 carbon atoms, and an aliphatic group having 2 to 12 carbon atoms is preferable. The spacer group is more preferably a chain, and may contain a non-adjacent oxygen atom or sulfur atom. Moreover, as a substituent, a halogen atom (fluorine, chlorine, bromine), a cyano group, a methyl group, or an ethyl group may be substituted.

As the mesogenic group represented by M, all known mesogenic groups can be used, and among them, a group represented by the following general formula (IX) is preferable.
General formula (IX)
− (− W ¹ −L ¹⁵ ) _n −W ² −
W ¹ and W ² each independently represents a divalent cycloaliphatic group, a divalent aromatic group or a divalent heterocyclic group. W ¹ and W ² are preferably 1,4-cyclohexanediyl, 1,4-phenylene, naphthalene-2,6-diyl, naphthalene-1,5-diyl and the like. In the case of 1,4-cyclohexanediyl, there are structural isomers of a trans isomer and a cis isomer. In the present invention, either isomer may be used, and a mixture in any ratio may be used. preferable. L ¹⁵ represents a group represented by L ^{11 to} L ¹⁴ and CH ₂ —O— or —O—CH ₂ —. L ¹⁵ is preferably —CH ₂ —O—, —O—CH ₂ —, —CO—O—, —CO—NR ³¹ —, —NR ³¹ —CO— or —O—CO—. n represents 1, 2 or 3, and is preferably 2. W ¹ and W ² may have a substituent, and examples of the substituent include a halogen atom (fluorine, chlorine, bromine, iodine), a cyano group, and an alkyl group having 1 to 10 carbon atoms (methyl group, ethyl). Group, propyl group, etc.), C1-10 alkoxy group (methoxy group, ethoxy group, etc.), C1-10 acyl group (formyl group, acetyl group, etc.), C2-10 carbon atom, etc. Examples include alkoxycarbonyl groups (methoxycarbonyl groups, ethoxycarbonyl groups, etc.), acyloxy groups having 2 to 10 carbon atoms (acetyloxy groups, propionyloxy groups, etc.), nitro groups, trifluoromethyl groups, difluoromethyl groups, and the like. . R ³¹ is the same as described in the general formula (IV). Preferred basic skeletons of mesogenic groups represented by the general formula (IX) are as follows. These may be substituted with the above substituents.

  Of these, the following basic skeletons are particularly preferable.

  Specific examples of the compound represented by the general formula (IV) of the present invention are shown below, but the present invention is not limited thereto. The compound represented by the general formula (IV) can be synthesized with reference to the method described in JP-T-11-513019.

  The first optically anisotropic layer is coated with a coating liquid containing the rod-shaped liquid crystalline compound and other additives such as a polymerization initiator on the alignment film, dried, and aligned with the molecules of the rod-shaped liquid crystalline compound. Can be produced. The details of the production method are the same as those described in the production method of the optically anisotropic film of the present invention. Available alignment film, polymerization initiator used for immobilization of liquid crystalline molecules, immobilization method, and coating The preparation of the liquid is the same as described above.

  The first optically anisotropic layer may be made of a polymer film. A stretched thermoplastic polymer film having positive refractive index anisotropy is preferably used. Examples of the thermoplastic polymer include one kind selected from a polymer group such as polyarylate, polyester, polycarbonate, polyolefin, polyether, polysulfine, polysulfone, and polyethersulfone, or 2 More than types. Among these, a polycarbonate copolymer, a polyester copolymer, a polyester carbonate copolymer, and a polyarylate copolymer are preferable, and a polycarbonate copolymer is more preferable. The polycarbonate copolymer is preferably a polycarbonate copolymer having a fluorene skeleton, and is obtained by reacting bisphenols with a carbonate ester-forming compound such as phosgene or diphenyl carbonate from the viewpoint of transparency, heat resistance, and productivity. Polycarbonate copolymers are particularly preferred. The component having a fluorene skeleton is preferably contained in an amount of 1 to 99 mol%. It is preferable that the said polycarbonate copolymer has a repeating unit represented by general formula (I) and general formula (II) as described in international patent 00/26705.

  The thermoplastic polymer film is a film in which a thermoplastic polymer is oriented by stretching. As a method for producing such a film, a known melt extrusion method, solution casting method, or the like is used. From the viewpoint of appearance, thickness unevenness, etc., the solution casting method is more preferably used. As the solvent in the solution casting method, methylene chloride, dioxolane and the like are used. Moreover, although a well-known method can be used also for the extending | stretching method, longitudinal uniaxial stretching is preferable.

  When the first optically anisotropic layer is made of a polymer, the thickness thereof is not particularly limited as long as Re is 40 to 150 nm. However, from the viewpoint of thinning and ease of handling during production, 20 ˜200 μm is preferable, and 40 μm to 150 μm is more preferable.

  The present invention will be described more specifically with reference to the following examples. The materials, reagents, amounts and ratios of substances, operations, and the like shown in the following examples can be appropriately changed without departing from the gist of the present invention. Therefore, the scope of the present invention is not limited to the following specific examples.

[Example 1]
(Synthesis of fluorinated polymer (P-13))

In a reactor equipped with a stirrer and a reflux condenser, 8.0 g of 2- (perfluorohexyl) ethyl acrylate (manufactured by Daikin Industries, Ltd.), 12.0 g of N, N-dimethylacrylamide (manufactured by Wako Pure Chemical Industries), dimethyl The reaction was completed by adding 1.1 g of -2,2'-azobisisobutyrate and 30 g of 2-butanone and heating to 78 ° C. for 6 hours under a nitrogen atmosphere. The weight average molecular weight was 1.7 × 10 ⁴ .

  Fluorine-containing polymers (P-3) and (P-33) were synthesized by a similar method.

[Example 2]
A liquid crystal display device having the configuration shown in FIG. 1 was produced. That is, the upper polarizing plate 1, the liquid crystal cell (upper substrate 5, liquid crystal layer 7, lower substrate 8), and lower polarizing plate 12 were laminated from the observation direction (upper layer), and a backlight light source (not shown) was further arranged. A first optical anisotropic layer 3 and a second optical anisotropic layer 10 for improving the optical performance of the liquid crystal display device were disposed between the upper and lower polarizing plates and the liquid crystal cell. As the upper polarizing plate 1 and the lower polarizing plate 12 used, from the configuration shown in FIG. 2, the protective film 101, the polarizing film 103, and the protective film 105 (assuming that the protective film 105 is disposed closer to the liquid crystal cell). For the upper polarizing plate 1, an integrated upper polarizing plate in which the protective film 105 is also used as a transparent support for the first optical anisotropic layer 3 and the optical anisotropic layer 3 is integrated. After producing the plate, it was incorporated into a liquid crystal display device. Similarly, for the lower polarizing plate 12, an integrated lower polarizing plate in which the protective film 105 is also used as a transparent support of the second optical anisotropic layer 10 and the optical anisotropic layer 10 is integrated is used. After fabrication, it was incorporated into a liquid crystal display device.

Below, the manufacturing method of each used member is demonstrated.
<Production of liquid crystal cell>
A VA mode liquid crystal cell was fabricated by the following procedure. After applying an alignment film (for example, JALS204R manufactured by JSR Corporation) to the substrate surface, the tilt angle with respect to the so-called substrate surface, which is a director indicating the alignment direction of liquid crystalline molecules, was set to about 89 ° by rubbing treatment. The cell gap between the upper and lower substrates was 3.5 μm, and a liquid crystal (MLC-6608 manufactured by Merck) with a negative dielectric anisotropy and Δn = 0.0813 and Δε = −4.6 was dropped between them. Enclosed.

<Production of integrated upper polarizing plate>
A polarizing film was prepared by adsorbing iodine to a stretched polyvinyl alcohol film. A commercially available cellulose triacetate film (Fujitac TD80UF, manufactured by Fuji Photo Film Co., Ltd.) subjected to saponification treatment was used for the transparent protective film (101 in FIG. 2) on the side far from the liquid crystal cell. The protective film had an Re value of 3 nm and an Rth value of 50 nm. On the other hand, the transparent support A prepared by the following method and saponified was used for the transparent protective film (105 in FIG. 2) on the side close to the liquid crystal cell.

(Preparation of transparent support A)
The following composition was put into a mixing tank and stirred while heating to dissolve each component to prepare a cellulose acetate solution.
Cellulose acetate solution composition Cellulose acetate having an acetylation degree of 60.7 to 61.1% 100 parts by weight Triphenyl phosphate (plasticizer) 7.8 parts by weight Biphenyl diphenyl phosphate (plasticizer) 3.9 parts by weight Methylene chloride (first Solvent) 336 parts by mass Methanol (second solvent) 29 parts by mass

  In another mixing tank, 16 parts by mass of the following retardation increasing agent, 92 parts by mass of methylene chloride and 8 parts by mass of methanol were added and stirred while heating to prepare a retardation increasing agent solution. A dope was prepared by mixing 474 parts by mass of the cellulose acetate solution with 25 parts by mass of the retardation increasing agent solution and stirring sufficiently. The addition amount of the retardation increasing agent was 3.5 parts by mass with respect to 100 parts by mass of cellulose acetate.

  The obtained dope was cast using a band stretching machine. After the film surface temperature on the band reached 40 ° C., the film was dried with warm air of 70 ° C. for 1 minute, and the film was dried from the band with 140 ° C. of drying air for 12 minutes. A cellulose acetate film (thickness: 80 μm) was prepared. About the produced cellulose acetate film, Re value and Rth value in wavelength 550nm were measured using KOBRA 21ADH (Oji Scientific Instruments Co., Ltd. product). Re was 2 nm (variation ± 1 nm), and Rth was 120 nm (variation ± 3 nm). Furthermore, Re of each wavelength of 400 nm to 700 nm was in the range of 2 ± 1 nm, and Rth of each wavelength of 400 nm to 700 nm was in the range of 120 ± 2 nm. The produced cellulose acetate film was immersed in a 2.0N potassium hydroxide solution (25 ° C.) for 2 minutes, neutralized with sulfuric acid, washed with pure water, and then dried. The surface energy of the cellulose acetate film was determined by a contact method and found to be 63 mN / m. The cellulose acetate film thus prepared was used as a transparent support A.

(Formation of alignment film)
Next, 26.3 ml / m ² of a coating solution having the following composition was applied to the opposite surface of the produced transparent support A with a # 15 wire bar coater.
Composition film coating liquid composition 4 parts by mass of the following polymer compound P 3 parts by mass Triethylamine 2 parts by mass 5% aqueous solution of DECONAL EX-521 (epoxy compound of Nagase Kasei Kogyo Co., Ltd.) 8.1 parts by mass Water 57 parts by mass Methanol 29 parts by mass

  Drying was performed at 25 ° C. for 30 seconds and 120 ° C. warm air for 120 seconds. The thickness of the dried film was 1.0 μm. Further, the surface roughness of the film was measured with an atomic force microscope (AFM: Atomic Force Microscope, SPI3800N, manufactured by Seiko Instruments Inc.), and found to be 1.135 nm. Next, the formed film was rubbed in the same direction as the slow axis 106 (longitudinal direction: wavelength 550 nm measurement) of the transparent support A.

(Formation of first optically anisotropic layer)
A first optically anisotropic layer was formed on the formed alignment film. Specifically, on the rubbing surface of the alignment film, a coating solution having the following composition is continuously applied using a bar coater, dried and heated (alignment aging), and further irradiated with ultraviolet rays to obtain a thickness. A first optically anisotropic layer having a horizontal orientation of 0.7 μm was formed.
1st coating liquid composition for optically anisotropic layers The rod-shaped liquid crystalline compound (exemplary compound IV-2) in this specification 38.1 mass%
Sensitizer A 0.38% by mass
The following photopolymerization initiator B 1.14% by mass
Orientation control agent C 0.19 mass%
Glutaraldehyde 0.04% by mass
Methyl ethyl ketone 60.1% by mass

  The formed first optically anisotropic layer 3 had a slow axis 4 in a direction perpendicular to the longitudinal direction (rubbing direction) of the transparent support A, and the Re value at 550 nm was 85 nm. Further, it had an optically positive refractive index anisotropy, and the Re value in the entire visible light range was 91 ± 9 nm.

  The laminated body of the produced transparent support A and the first optically anisotropic layer, and the cellulose triacetate film Fujitac TD80UF were attached to both sides of the produced polarizing film using a polyvinyl alcohol-based adhesive. A body-type upper polarizing plate was prepared. In FIG. 2, the transparent protective film 101 far from the liquid crystal cell side is Fujitac TD80UF, and the transparent protective film 105 near the liquid crystal cell is the transparent support A. When the stacking angle of each film is based on the left and right directions when the display device is viewed from above (0 °), the angle of the upper polarizing plate protective film slow axis 102 is 0 °, the angle of 106 is 0 °, and The angle of the polarizing film absorption axis 104 (2 in FIG. 1) was set to 0 °. The integrated upper polarizing plate of the upper polarizing plate 1 and the first optically anisotropic layer 3 manufactured in this way is arranged so that the first optically anisotropic layer 3 is closer to the upper liquid crystal cell substrate 5. Incorporated into a liquid crystal display device.

<Preparation of integrated lower polarizing plate>
As the protective film of the lower polarizing film, a commercially available cellulose triacetate film (Fujitac TD80UF, manufactured by Fuji Photo Film Co., Ltd., Re value is 3 nm, Rth value is 50 nm) was used as the protective film of the upper polarizing film.
(Formation of alignment film)
On the produced cellulose acetate film (A), a coating solution having the following composition was applied at 24 ml / m ² with a # 14 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. ───────────────────────────────────
Alignment film coating solution composition ───────────────────────────────────
Modified polyvinyl alcohol of the following formula 40 parts by weight Water 728 parts by weight Methanol 228 parts by weight Glutaraldehyde (crosslinking agent) 2 parts by weight Citric acid 0.08 parts by weight Citric acid monoethyl ester 0.29 parts by weight Citric acid diethyl ester 0.27 Parts by mass Triethyl citrate 0.05 parts by mass ───────────────────────────────────

  Drying was performed at 25 ° C. for 60 seconds, 60 ° C. warm air for 60 seconds, and 90 ° C. warm air for 150 seconds. The thickness of the dried film was 1.1 μm. Further, the surface roughness of the film was measured by an atomic force microscope (AFM: Atomic Force Microscope, SPI3800N, manufactured by Seiko Instruments Inc.), and found to be 1.147 nm.

(Formation of second optically anisotropic layer)
A coating liquid containing a discotic liquid crystal having the following composition was coated on the formed alignment film.
Composition of coating liquid for discotic liquid crystal layer Discotic liquid crystal compound (1) * 1 32.6% by mass
Fluoropolymer in this specification (Exemplary Compound P-13) 0.07% by mass
Ethylene oxide modified trimethylolpropane triacrylate (V # 360, manufactured by Osaka Organic Chemical Co., Ltd.) 3.2% by mass
Sensitizer (Kayacure DETX, manufactured by Nippon Kayaku Co., Ltd.) 0.4% by mass
Photopolymerization initiator (Irgacure 907, manufactured by Ciba Geigy) 1.1% by mass
Methyl ethyl ketone 62.0% by mass
* 1: As the discotic liquid crystalline compound (1), 1,2,1 ′, 2 ′, 1 ″, 2 ″ -tris [4,5-di (vinylcarbonyloxybutoxybenzoyloxy) phenylene (Japanese Patent Laid-Open No. Hei 8- Example compound TE-8 (8), m = 4) described in Japanese Patent No. 50206, paragraph 0044 was used.

  Then, it dried by heating for 2 minutes in a 130 degreeC drying zone, and orientated the discotic compound. Next, UV irradiation was performed for 4 seconds using a 120 W / cm high-pressure mercury lamp at 130 ° C. to polymerize the discotic compound. Thereafter, the film was allowed to cool to room temperature, a thickness of 3.0 μm, an optically negative refractive index anisotropy, and a second optical anisotropic layer with Re = 0 nm and Rth = 140 nm for visible light Formed. The discotic liquid crystalline compound of the second optically anisotropic layer was horizontally aligned within a range of ± 2 °.

  The laminated body of Fujitac TD80UF and the second optically anisotropic layer and Fujitac TD80UF thus produced were attached to both surfaces of the polarizing film using a polyvinyl alcohol-based adhesive to produce an integrated polarizing plate. When the stacking angle of each film is based on the left and right directions when the display device is viewed from above (0 °), the axis angle of the polarizing film absorption axis 104 (13 in FIG. 1) is 90 ° in FIG. The angles of the protective film slow axes 102 and 106 were set to 90 °. The produced integrated lower polarizing plate was incorporated into a liquid crystal display device so that the second optical anisotropic layer 10 was in contact with the upper liquid crystal cell substrate 8.

[Evaluation of liquid crystal display devices]
<Measurement of leakage light of the manufactured liquid crystal display device>
The viewing angle dependence of the transmittance of the liquid crystal display device thus manufactured was measured. The elevation angle was measured from the front in an oblique direction up to 80 ° every 10 °, and the azimuth was measured up to 360 ° every 10 ° on the basis of the horizontal right direction (0 °). It has been found that the luminance at the time of black display increases as the elevation angle increases from the front direction, and the leakage light transmittance increases and takes a maximum value near the elevation angle of 60 °. It was also found that the contrast, which is the ratio between the white display transmittance and the black display transmittance, deteriorates as the black display transmittance increases. Therefore, it was decided to evaluate the viewing angle characteristics based on the maximum values of the black display transmittance at the front and the leakage light transmittance at an elevation angle of 60 °. The front transmittance in this example was 0.05%, and the maximum value of leakage light transmittance at an elevation angle of 60 ° was 0.1% at an azimuth angle of 30 °.

<Evaluation of unevenness>
Unevenness was evaluated by preparing a front black display and viewing from an elevation angle of 60 °. The evaluation criteria are as follows.
○: No unevenness is observed on the entire surface.
○: Slightly uneven.
Δ: Some unevenness has occurred.
X: Unevenness occurs on the entire surface.

[Examples 3 and 4]
The fluorine-containing polymer (Exemplary Compound P-13) in this specification is changed to Exemplified Compounds P-3 and P-33, and the second optically anisotropic layer (Re = 0 nm, Rth = A liquid crystal display device was produced in the same manner as in Example 2 except that 140 nm) was produced.

[Comparative Example 1]
In producing the second optically anisotropic layer, the fluoropolymer (Exemplary Compound P-13) in this specification is replaced with Comparative Compound 1 (Exemplary Compound FS-3 described in JP-A No. 11-352328). A liquid crystal display device was produced in the same manner as in Example 2 except that.

[Comparative Example 2]
In the production of the second optically anisotropic layer, the fluoropolymer (Exemplary Compound P-13) in this specification is replaced with Comparative Compound 1 (Exemplary Compound MM-2 described in JP-A No. 11-352328). A liquid crystal display device was produced in the same manner as in Example 2 except that.

[Comparative Example 3]
In the production of the second optically anisotropic layer, the fluoropolymer (Exemplary Compound P-13) in this specification was used as the comparative fluoropolymer 1 (Example 2 of JP-A-11-148080). Polymer (1): A liquid crystal display device was produced in the same manner as in Example 2 except that the content of the fluoroaliphatic group-containing monomer was 19% by mass.
[Comparative Example 4]
A liquid crystal display device was produced in the same manner as in Example 2 except that the fluoropolymer (Exemplary Compound P-13) in this specification was not used in the production of the second optically anisotropic layer.
[Comparative Example 5]
A liquid crystal display device was produced in the same manner as in Example 2 except that the second optically anisotropic layer was not produced.

For each of the manufactured liquid crystal display devices, leakage light and unevenness were evaluated in the same manner as in Example 2. The results are shown in Table 1. Further, the inclination angle in the vicinity of the alignment film of the liquid crystalline compound and the inclination angle in the vicinity of the air interface in the optically anisotropic layer were calculated by the methods described below. In an optically anisotropic layer in which a discotic compound or rod-shaped compound is oriented, the inclination angle on one surface of the optically anisotropic layer (the physical target axis in the discotic compound or rod-shaped compound is the interface of the optically anisotropic layer) It is difficult to directly and accurately measure the angle θ1 and the angle θ2 of the other surface. Therefore, in this specification, θ1 and θ2 are calculated by the following method. Although this method does not accurately represent the actual orientation state of the present invention, it is effective as a means for expressing the relative relationship of some optical properties of the optical film.
In this method, in order to facilitate calculation, the following two points are assumed and the inclination angles at the two interfaces of the optically anisotropic layer are used.
1. The optically anisotropic layer is assumed to be a multilayer body composed of layers containing a discotic compound or a rod-like compound. Further, it is assumed that the minimum unit layer (the tilt angle of the discotic compound or rod-shaped compound is assumed to be uniform in the layer) constituting the optical axis is optically uniaxial.
2. It is assumed that the inclination angle of each layer changes monotonically with a linear function along the thickness direction of the optically anisotropic layer.
The specific calculation method is as follows.
(1) The angle of incidence of the measurement light on the optically anisotropic layer is changed within a plane in which the inclination angle of each layer changes monotonically with a linear function along the thickness direction of the optically anisotropic layer. The retardation value is measured at the measurement angle. In order to simplify measurement and calculation, it is preferable to measure the retardation value at three measurement angles of −40 °, 0 °, and + 40 °, with the normal direction to the optically anisotropic layer being 0 °. Such measurements include KOBRA-21ADH and KOBRA-WR (manufactured by Oji Scientific Instruments), transmission ellipsometer AEP-100 (manufactured by Shimadzu Corporation), M150 and M520 (manufactured by JASCO Corporation) ), ABR10A (manufactured by UNIOPT Co., Ltd.).
(2) In the above model, the refractive index of ordinary light of each layer is no, the refractive index of extraordinary light is ne (ne is the same value in all layers, and no is the same), and the thickness of the entire multilayer body is d And Furthermore, based on the assumption that the tilt direction of each layer and the uniaxial optical axis direction of that layer coincide with each other, the calculation of the angular dependence of the retardation value of the optically anisotropic layer agrees with the measured value. Fitting is performed using the tilt angle θ1 on one surface of the isotropic layer and the tilt angle θ2 of the other surface as variables, and θ1 and θ2 are calculated.
Here, for no and ne, known values such as literature values and catalog values can be used. If the value is unknown, it can also be measured using an Abbe refractometer. The thickness of the optically anisotropic layer can be measured by an optical interference film thickness meter, a cross-sectional photograph of a scanning electron microscope, or the like. The results are shown in Table 1. The measurement wavelength is 632.8 nm.

<Evaluation of liquid crystal display device (1)>

As can be seen from the results shown in Table 1, optical anisotropy formed from a composition containing a fluoropolymer P-13, P-3 or P-33 containing a fluoroaliphatic group and an amide group. In the layer, the molecules of the discotic liquid crystalline compound were substantially horizontally aligned. As a result, when this optically anisotropic layer is used as the second optically anisotropic layer, the optical compensation of the VA mode liquid crystal cell can be performed accurately, and a liquid crystal display device having a small leakage light and a high contrast ratio can be obtained. It was. Moreover, since the surface smoothness of the second optically anisotropic layer was improved by the addition of the fluoropolymer, a high-quality image display with little unevenness could be realized.
On the other hand, in the liquid crystal display devices of Comparative Examples 2 and 3 produced in the same manner as in Example 2 except that the fluoropolymer was replaced with Comparative Compound 1 or 2, the discotic liquid crystal was used in the second optically anisotropic phase. Although the active compound was substantially horizontally oriented, unevenness remained. Further, in the liquid crystal display device of Comparative Example 1 produced in the same manner as in Example 2 except that the fluoropolymer was replaced with the comparative fluoropolymer 1, the molecules of the discotic liquid crystalline compound were contained in the optically anisotropic layer. However, the film was not completely uniformly aligned horizontally, and schlieren defects existed. Therefore, compared to Example 2, the liquid crystal display device has a large leakage light and a low contrast ratio. The schlieren-like structure is an optical structure found in a discotic liquid crystalline compound and is described in pages 145 to 146 of a liquid crystal manual (edited by the Liquid Crystal Handbook Editorial Committee, Maruzen Co., Ltd., 2000). Further, even in the liquid crystal display device of Comparative Example 4 in which the second optically anisotropic layer does not contain the fluorine-containing polymer according to the present invention, the molecules of the discotic liquid crystalline compound are not horizontally aligned and many schlieren defects exist. Therefore, compared with Examples 2 to 4, the liquid crystal display device has a large leakage light and a low contrast ratio.
Further, the liquid crystal display device of Comparative Example 5 having no second optically anisotropic layer was also a liquid crystal display device having a large leakage light and a low contrast ratio.

  In addition, the laminated body of TD80UF and the second optically anisotropic layer produced in each example is sandwiched between two polarizing plates whose absorption axes are orthogonal to each other, and observed from various angles to cause unevenness. As a result of evaluation, the same results as the evaluation of unevenness in the table were obtained. By adding the fluorine-containing polymer of the present application, it was possible to produce an optically anisotropic film without unevenness. Therefore, it can be seen that in the present invention, it is preferable to use a fluoropolymer containing a fluoroaliphatic group-containing monomer and an amide group-containing monomer.

[Example 5]
Example 2 is the same as Example 2 except that ethylene oxide-modified trimethylolpropane triacrylate (V # 360, manufactured by Osaka Organic Chemical Co., Ltd.) was not added, but the same amount of orientation temperature reducing agent A was added instead. The second anisotropic layer was fabricated in the same manner as described above. As a result, the second anisotropic layer having a thickness of 3.0 μm, an optically non-refractive index anisotropy, and Re = 0 nm and Rth = 155 nm for visible light. An anisotropic layer was obtained. In the obtained second optically anisotropic layer, the molecules of the discotic liquid crystalline compound were horizontally aligned within a range of ± 2 °. From a comparison between this and Example 2, it can be seen that an optically anisotropic layer having the same film thickness and a large Rth can be obtained by adding the alignment temperature lowering agent A.

[Example 6]
An optically anisotropic layer having a film thickness of 2.7 μm was produced in exactly the same manner as in Example 5 except that the coating amount was changed so that Rth was 140 nm. As shown, a second optically anisotropic layer with Re = 0 nm and Rth = 140 nm for visible light was obtained. In the obtained second optically anisotropic layer, the molecules of the discotic liquid crystalline compound were horizontally aligned within a range of ± 2 °. A liquid crystal display device was produced in the same manner as in Example 2 except that the second optically anisotropic layer obtained here was used. As a result of evaluating leakage light and unevenness of the manufactured liquid crystal display device in the same manner as in Example 2, optical compensation of the VA mode liquid crystal cell can be performed accurately as in Example 2, and the leakage light is small and the contrast ratio is reduced. Liquid crystal display device. Moreover, since the surface smoothness of the second optically anisotropic layer was improved by the addition of the fluoropolymer, a high-quality image display with little unevenness could be realized.
In addition, the laminated body of TD80UF and the second optically anisotropic layer produced in Example 6 is sandwiched between two polarizing plates whose absorption axes are orthogonal to each other, and observed from various angles to cause unevenness. As a result of the evaluation, the same result as the evaluation of unevenness in Example 2 was obtained.
From this, it became clear that by using the alignment temperature lowering agent A, the film thickness of the second optical anisotropic layer can be reduced and the same optical performance can be obtained. This is advantageous in that it can be made thinner and in terms of manufacturing cost.

It is the schematic which shows an example of the liquid crystal display device of this invention. It is the schematic which shows an example of the polarizing plate which can be used for this invention.

Explanation of symbols

1 Upper polarizing plate 2 Upper polarizing plate absorption axis 3 First optical anisotropic layer 4 First optical anisotropic layer slow axis direction 5 Upper electrode substrate of liquid crystal cell 6 Upper substrate alignment control direction 7 Liquid crystalline molecule 8 Liquid crystal cell lower electrode substrate 9 Lower substrate orientation control direction 10 Second optical anisotropic layer 12 Lower polarizing plate 13 Lower polarizing plate absorption axis direction 101 Polarizing plate protective film 102 Polarizing plate protective film slow axis direction 103 Polarizing plate polarizing film 104 Polarizing film absorption axis direction 105 Polarizing plate protective film 106 Polarizing plate protective film slow axis direction

Claims (15)

Optical anisotropy having at least one optically anisotropic layer formed from a composition containing a discotic liquid crystalline compound and at least one fluoropolymer having a fluoroaliphatic group and an amide group on a support the film. The optically anisotropic film according to claim 1, wherein the fluorine-containing polymer includes a polymer unit derived from a fluoroaliphatic group-containing monomer and a polymer unit derived from an amide group-containing monomer. The optically anisotropic film according to claim 1 or 2, wherein molecules of the discotic liquid crystalline compound are substantially horizontally aligned in the optically anisotropic layer. The optically anisotropic film according to any one of claims 1 to 3, wherein the optically anisotropic layer has Re of 10 nm or less and Rth of 60 to 250 nm with respect to visible light. 5. The polymer according to claim 1, wherein the fluoropolymer is a polymer including at least one polymer unit of a fluoroaliphatic group-containing monomer represented by the following general formula (I) or general formula (II). Optical anisotropic film:

In the formula, R ¹ and R ² represent a hydrogen atom, a halogen atom or a methyl group, L ¹ and L ² each represent a divalent linking group, and m and n each independently represents an integer of 1 to 18. . The optically anisotropic film according to any one of claims 1 to 5, wherein the fluoropolymer is a polymer containing at least one polymerized unit of an amide group-containing monomer represented by the following general formula (III):

In the formula, R ³ represents a hydrogen atom, a halogen atom or a methyl group, and R ¹⁰ and R ¹¹ are each independently a hydrogen atom, an alkyl group having 1 to 18 carbon atoms, an aromatic group having 6 to 20 carbon atoms or a carbon number. 1-20 heterocyclic groups are represented. R ¹⁰ and R ¹¹ may be connected to each other to form a heterocyclic ring. The optically anisotropic film according to any one of claims 1 to 6, wherein the optically anisotropic layer contains at least one discotic compound different from the discotic liquid crystalline compound. The optically anisotropic film according to claim 1, wherein the discotic liquid crystalline compound is a triphenylene liquid crystalline compound. A polarizing plate comprising the optically anisotropic film according to claim 1 and a polarizing film, wherein the optically anisotropic film also serves as at least one protective film of the polarizing film. . Between the two polarizing plates whose absorption axes are orthogonal to each other and the two polarizing films, a pair of substrates and a liquid crystal layer made of liquid crystalline molecules sandwiched between the substrates, and an external electric field In a non-driven state where no voltage is applied, the liquid crystal molecule is aligned in a direction substantially perpendicular to the substrate, and has an optically positive refractive index anisotropy. A liquid crystal display comprising at least one first optical anisotropic layer having a thickness of 40 to 150 nm and the optical anisotropic film according to any one of claims 1 to 8 as a second optical anisotropic layer. apparatus. The liquid crystal display device according to claim 10, wherein the optically anisotropic film also serves as at least one protective film of the two polarizing films. The liquid crystal display device according to claim 10, wherein the first optically anisotropic layer is a layer formed from a rod-like liquid crystalline compound or a polymer. The liquid crystal display device according to any one of claims 10 to 12, wherein the first optically anisotropic layer is a layer formed from a rod-like liquid crystalline compound represented by the following general formula (IV).
Formula (IV)
Q ¹ -L ¹¹ -A ¹ -L ¹³ -ML ¹⁴ -A ² -L ¹² -Q ²
In the formula, Q ¹ and Q ² each independently represent a polymerizable group, L ¹¹ , L ¹² , L ¹³ and L ¹⁴ each independently represent a single bond or a divalent linking group, and A ¹ and A ² are Each independently represents a spacer group having 2 to 20 carbon atoms, and M represents a mesogenic group. The first optically anisotropic layer is a layer formed from a rod-like liquid crystalline compound, and the molecules of the rod-like liquid crystalline compound in the first optically anisotropic layer are absorbed by the two polarizing films. The liquid crystal display device according to claim 10, wherein the liquid crystal display device is fixed in a state of being horizontally aligned in a direction substantially perpendicular to one of the axes. The liquid crystal display device according to claim 10, wherein the first optically anisotropic layer and the second optically anisotropic layer are disposed with a liquid crystal cell interposed therebetween.

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