JP2006023543A - Optical compensation film, polarizing plate and liquid crystal display - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical compensation film which contributes to improvement of a visual field angle of a liquid crystal display without producing display unevenness or the like. <P>SOLUTION: The optical compensation film includes at least one layer of optically anisotropic layer which is formed by fixing alignment state of liquid crystal compounds. In the optically anisotropic layer, the liquid crystal compounds have hybrid alignment where an angle made by a director of a molecule and a layer flat surface changes in a depth direction of the layer and further have twist alignment where azimuth of a shaft obtained by projecting the director on the layer flat surface changes. Further the optically anisotropic layer contains a fluoroaliphatic group-containing polymer. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an optical compensation film having an optically anisotropic layer formed from a liquid crystal compound, and a polarizing plate and a liquid crystal display device using the same.

  The liquid crystal display device includes a liquid crystal cell, a polarizing element, and an optical compensation film (retardation plate). In the transmissive liquid crystal display device, two polarizing elements are arranged on both sides of the liquid crystal cell, and one or two optical compensation films are arranged between the liquid crystal cell and the polarizing element. In a reflective liquid crystal display device, a reflector, a liquid crystal cell, a single optical compensation film, and a single polarizing element are arranged in this order. The liquid crystal cell is composed of a rod-like liquid crystal molecule, two substrates for enclosing it, and an electrode layer for applying a voltage to the rod-like liquid crystal molecule. The liquid crystal cell is different in the alignment state of rod-like liquid crystal molecules. As for the transmissive type, TN (Twisted Nematic), IPS (In-Plane Switching), FLC (Ferroelectric Liquid Crystal), OCB (Optically Compensatory N) (OCB). Super Twisted Nematic), VA (Vertically Aligned), ECB (Electrically Controlled Birefringence), and reflection types are TN, HAN (Hybrid Aligned NeH), .

  Optical compensation sheets are used in various liquid crystal display devices in order to eliminate image coloring and expand the viewing angle. As an optical compensation sheet, a stretched birefringent polymer film has been conventionally used. It has been proposed to use an optical compensation sheet having an optically anisotropic layer formed from a low-molecular or high-molecular liquid crystalline compound on a transparent support, instead of the optical compensation sheet comprising a stretched birefringent film. Since liquid crystal compounds have various alignment forms, it has become possible to realize optical properties that cannot be obtained with conventional stretched birefringent polymer films by using liquid crystal compounds. Furthermore, it functions as a protective film for the polarizing plate.

  The optical properties of the optical compensation sheet are determined according to the optical properties of the liquid crystal cell, specifically, the display mode differences as described above. When a liquid crystal compound is used, optical compensation sheets having various optical properties corresponding to various display modes of the liquid crystal cell can be produced. Various optical compensation sheets using liquid crystal compounds corresponding to various display modes have already been proposed. For example, an optical compensation sheet for a TN mode liquid crystal cell optically compensates for an alignment state tilted on the substrate surface while eliminating the twisted structure of liquid crystal molecules by applying a voltage, and prevents contrast leakage by preventing light leakage in an oblique direction during black display. Improve viewing angle characteristics.

  In the TN mode liquid crystal display device, the twisted structure of the liquid crystal molecules in the liquid crystal cell is eliminated by applying an electric field. At that time, the optical compensation has an optically anisotropic layer in an alignment state inclined with respect to the substrate surface of the liquid crystal cell. Optical compensation is performed by a sheet to prevent light leakage in an oblique direction during black display and to improve the viewing angle characteristic of contrast. As a typical example of optical compensation, a film set in which stretched films having the same retardation are orthogonally laminated and in-plane retardation is brought close to 0 is disposed between the upper and lower polarizing plates and the liquid crystal cell, respectively (Patent Document 1). reference). However, the molecules in the liquid crystal cell are not completely vertically aligned with respect to the substrate when an electric field is applied, and remain in parallel alignment in the vicinity of the substrate. On the other hand, the liquid crystal molecules at the center of the substrate are vertically aligned, and the liquid crystal molecules between them are continuously tilted. In order to optically compensate for the alignment state of such a liquid crystal cell, the optical compensation sheet may have the same optical performance. As such an optical compensation sheet, there is one in which a liquid crystal compound is hybrid-oriented and fixed to form a film. For example, there are examples in which a discotic liquid crystalline compound is used as the liquid crystalline compound (see Patent Document 2) or a rod-shaped liquid crystalline compound is used (see Patent Document 3). In addition, there is an example of an optical compensation sheet in which a twisted structure is further introduced into a hybrid alignment state of a discotic liquid crystalline compound (see Patent Document 4). However, in the conventional technology, the optically anisotropic layer containing the liquid crystal compound with hybrid alignment and twist alignment is likely to generate repellency, and further, it is derived from the uneven alignment of the liquid crystal compound and the uneven thickness of the optical anisotropic layer. However, there is a problem that it is very difficult to obtain an optical compensation sheet having a uniform optical characteristic in a large area.

Japanese Patent Laid-Open No. 4-162018 JP-A-6-214116 JP-A-10-186356 Japanese Patent No. 3456891

  The present invention has been made in view of the above problems, and has an optically anisotropic layer formed from liquid crystalline molecules that contributes to the improvement of the viewing angle of a liquid crystal display device without causing display unevenness. It is an object of the present invention to provide a compensation film, a polarizing plate including the compensation film, and a liquid crystal display device, particularly a TN liquid crystal display device, which has a simple structure and has a significantly improved viewing angle.

Means for solving the above-mentioned problems are as follows.
[1] An optical compensation film including at least one optically anisotropic layer formed by fixing an alignment state of a liquid crystal compound, wherein the liquid crystal compound includes a molecular director and a layer plane. And a twisted orientation in which the orientation of the axis of the director projected onto the layer plane is changed, and the optical orientation is different. An optical compensation film in which the anisotropic layer contains a fluoroaliphatic group-containing polymer.
[2] The optical compensation film according to [1], wherein the fluoroaliphatic group-containing polymer is a polymer containing at least one repeating unit derived from a monomer represented by the following general formula (1).

（一般式（１）中、Ｒ¹は水素原子又はメチル基を表し、Ｘは酸素原子、イオウ原子または−Ｎ（Ｒ²）−を表し、Ｈ^fは水素原子またはフッ素原子を表し、Ｒ²は水素原子または炭素数１〜４のアルキル基を表す。ｍは１〜６の整数、ｎは２〜４の整数を表す。）

(In general formula (1), R ¹ represents a hydrogen atom or a methyl group, X represents an oxygen atom, a sulfur atom or —N (R ² ) —, H ^f represents a hydrogen atom or a fluorine atom, R ² Represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, m represents an integer of 1 to 6, and n represents an integer of 2 to 4.)

[3] The optical compensation film according to [2], wherein H ^f is a fluorine atom in the general formula (1).
[4] The optical compensation film according to any one of [1] to [3], wherein the liquid crystal compound is a discotic liquid crystal compound.
[5] The optical compensation film according to any one of [1] to [4], further comprising a support for supporting the optically anisotropic layer.
[6] The optical compensation film according to [5], wherein the support is a cellulose ester film.
[7] A polarizing plate in which the optical compensation film according to any one of [1] to [6] and a polarizing film are laminated.
[8] A liquid crystal display device comprising the optical compensation film of any one of [1] to [6] or the polarizing plate of [7].

[9] A polarizing plate in which the optical compensation film according to any one of [1] to [6] and a polarizing film are laminated, and molecules of the liquid crystal compound at the interface near the polarizing film of the optically anisotropic layer [7] The polarizing plate according to [7], wherein the orientation of the axis projected on the layer plane is not parallel to either the transmission axis or the absorption axis of the polarizing film.
[10] A polarizing plate in which the optical compensation film according to any one of [1] to [6] and a polarizing film are laminated, and the molecules of the liquid crystal compound at the interface far from the polarizing film of the optically anisotropic layer [7] The polarizing plate according to [7], wherein the direction of the axis projected on the plane of the director is not parallel to either the transmission axis or the absorption axis of the polarizing film.
[11] A polarizing plate in which the optical compensation film according to any one of [1] to [6] and a polarizing film are laminated, and one of the transmission axis and the absorption axis of the polarizing film is the optical anisotropy. [7] The polarizing plate according to [7], which is between the azimuths of the axes obtained by projecting the directors of the liquid crystal compound molecules on the interface near and far from the polarizing film of the layer onto the plane of the layer.
[12] A liquid crystal display device comprising the polarizing plate according to any one of [9] to [11].

  According to the present invention, an optical compensation film having an optically anisotropic layer formed from liquid crystalline molecules that contributes to an improvement in the viewing angle of a liquid crystal display device without causing display unevenness, a polarizing plate including the same, In addition, it is possible to provide a liquid crystal display device, in particular, a TN liquid crystal display device, which has a simple configuration and a significantly improved viewing angle.

BEST MODE FOR CARRYING OUT THE INVENTION

  In the present specification, “45 °”, “parallel” or “orthogonal” means that the angle is within a range of strictly less than ± 5 °. The error from the exact angle is preferably less than 4 °, more preferably less than 3 °. As for the angle, “+” means the counterclockwise direction, and “−” means the clockwise direction. Further, the “slow axis” means a direction in which the refractive index is maximized. The “visible light region” means 380 nm to 780 nm. Further, the measurement wavelength of the refractive index is a value at λ = 550 nm in the visible light region unless otherwise specified. Furthermore, the “alignment control direction of the liquid crystalline compound in the optically anisotropic layer” means that the liquid crystalline compound is aligned in a predetermined direction at the interface with the optically anisotropic layer, such as the rubbing treatment direction applied to the alignment film. This means the direction of treatment applied to the alignment film or the support.

  In this specification, “polarizing plate” is cut into a size to be incorporated into a long polarizing plate and a liquid crystal device unless otherwise specified (in this specification, “cutting” includes “punching” and “cutting out”. It is used in the meaning including both of the polarizing plates. In this specification, “polarizing film” and “polarizing plate” are distinguished from each other. “Polarizing plate” means a laminate having a transparent protective film for protecting the polarizing film on at least one side of the “polarizing film”. It shall be.

In this specification, the in-plane retardation value (Re) and the thickness direction retardation value (Rth) of the film are defined by the following mathematical formulas (I) and (II), respectively.
Formula (I): Re = (nx−ny) × d
Formula (II): Rth = {(nx + ny) / 2−nz} × d
In the mathematical expressions (I) and (II), nx is the refractive index in the slow axis direction (the direction in which the refractive index is maximum) in the film plane. In the formulas (I) and (II), ny is the refractive index in the fast axis direction (the direction in which the refractive index is minimum) in the film plane. In the formula (II), nz is a refractive index in the thickness direction of the film. In the formulas (I) and (II), d is the thickness of the film whose unit is nm.

  In the present invention, the optical characteristics of the optically anisotropic layer containing a liquid crystal compound are calculated as follows. The tilt angle of the liquid crystal compound in the optically anisotropic layer near the alignment film, the tilt angle of the air interface, and the average tilt angle were changed using an ellipsometer (M-150, manufactured by JASCO Corporation). The retardation is measured, hypothesized as a refractive index ellipsoid model, and calculated by the method described in “Designing Concepts of the Discrete Negative Birefringence Compensation Films SID98 DIGEST”.

[Optical compensation film]
The optical compensation film of the present invention includes an optically anisotropic layer formed by fixing the alignment state of a liquid crystal compound, and the liquid crystal compound has an angle formed by a molecular director and the plane of the optically anisotropic layer. And a twisted orientation in which the orientation of the axis of the director projected on the plane of the optically anisotropic layer is changed. Furthermore, the optically anisotropic layer contains a fluoroaliphatic group-containing polymer together with a liquid crystalline compound.

  In the optically anisotropic layer, the liquid crystalline molecules are in a hybrid alignment state in which an angle formed by the director and the layer plane (hereinafter sometimes referred to as “tilt angle”) changes in the thickness direction of the film, and It is fixed in an orientation state twisted in the thickness direction at a twist angle φ. FIG. 1 schematically shows the alignment state of the discotic liquid crystalline molecules. When the liquid crystal molecule is a discotic liquid crystal molecule, the director is parallel to the normal direction of the disc surface of the molecule, and when the liquid crystal molecule is a rod-like liquid crystal molecule, the director is the major axis of the molecule. Parallel to the direction. As shown in FIG. 1, the optical compensation film of the present invention comprises a transparent support 3 and an optically anisotropic layer 4. The optically anisotropic layer 4 has a discotic liquid crystalline molecule d having a twist angle φ. In a hybrid orientation state in which the tilt angle (angle formed by the major axis de and the layer plane) increases while twisting and having a local fluctuation in the thickness direction from the transparent support interface to the air interface. It is fixed. In order to cancel the twisted structure and refractive index anisotropy of the liquid crystal layer of the liquid crystal cell, the twisted orientation of the liquid crystal layer is observed when the twisted orientation of the optically anisotropic layer is observed from the surface arranged on the display surface side. It is preferable to arrange so as to be opposite. For example, when the optical compensation film of the present invention is disposed between the display-side polarizing film and the liquid crystal cell and the optical anisotropic layer is disposed on the liquid crystal cell side, the arrow from the bottom to the top in FIG. When observed from the a direction shown, it is preferably fixed to a twisted orientation opposite to the twisted orientation of the liquid crystal cell. On the other hand, when the optical compensation film of the present invention is disposed between the back-side polarizing film and the liquid crystal cell and the optically anisotropic layer is disposed on the liquid crystal cell side, the arrow from top to bottom in FIG. When observed from the b direction shown, it is preferably fixed to a twisted orientation opposite to the twisted orientation of the liquid crystal cell.

  The preferable average tilt angle β and the preferable twist angle φ of the optically anisotropic layer are determined according to Rth of the transparent support, the thickness d of the optically anisotropic layer, and the like. When used for compensation, in general, the average inclination angle β is preferably 30 to 60 °, and more preferably 35 to 55 °.

  In the optically anisotropic layer, since the discotic liquid crystalline molecules are hybrid-aligned, the inclination angle of the disc surface of the molecule with respect to the layer plane is determined by the depth direction of the optically anisotropic layer and the distance from the support interface. Increasing or decreasing with fluctuations. The angle of inclination preferably increases with increasing distance. Further, the change in the tilt angle can be continuous increase, continuous decrease, intermittent increase, intermittent decrease, change including continuous increase and continuous decrease, or intermittent change including increase and decrease. . The intermittent change includes a region where the inclination angle does not change in the middle of the thickness direction. In the present invention, even if a region where the inclination angle does not change is included, it may be increased or decreased as a whole. Furthermore, it is preferable that the inclination angle changes continuously.

  Further, in the optically anisotropic layer, the discotic liquid crystalline molecules are twisted and oriented so that the director is twisted from one interface to the other in the thickness direction of the optically anisotropic layer. The angle φ is twisted. The preferable range of the twist angle φ is preferably 1 ° to 30 °, more preferably 2 ° to 25 °, and more preferably 3 ° to 20 °. The twist orientation in the optically anisotropic layer is preferably less than 1 pitch. The direction of the twist alignment may be clockwise or counterclockwise, but it is preferable that the twist alignment is opposite to the twist direction of the liquid crystal in the liquid crystal cell to be optically compensated.

  Other optical characteristics of the optically anisotropic layer are not particularly limited, and a preferable range is determined according to the application to be used. In general, the in-plane retardation Re is preferably 10 to 120 nm, and more preferably 20 to 90 nm.

  As long as the optically anisotropic layer contained in the optical compensation film of the present invention satisfies the above alignment state, the kind of the liquid crystalline compound is not particularly limited, and may be a discotic liquid crystal or a rod-shaped liquid crystal. Further, not only low-molecular liquid crystalline compounds but also high-molecular liquid crystalline compounds can be used. For example, by aligning a low-molecular liquid crystalline compound in the liquid crystal state and fixing the alignment by photocrosslinking or thermal crosslinking, or aligning the liquid crystalline compound in the liquid crystal state and cooling An optically anisotropic layer obtained by fixing the orientation can be used. In the present invention, even when a liquid crystalline compound is used for the optically anisotropic layer, the optically anisotropic layer is a layer formed by fixing the compound by polymerization or the like, and thus becomes a layer. After that, it is no longer necessary to show liquid crystallinity. The liquid crystal compound used for forming the optically anisotropic layer is preferably a polymerizable liquid crystal compound. The polymerizable liquid crystal may be multifunctional or monofunctional. When the optical compensation film of the present invention is applied to a TN liquid crystal display device, the liquid crystal compound is preferably a discotic liquid crystal compound.

  The optically anisotropic layer included in the optical compensation film of the present invention includes a fluoroaliphatic group-containing polymer. The optically anisotropic layer containing a liquid crystalline compound is formed by applying a coating liquid comprising a composition containing a liquid crystalline compound and a fluoroaliphatic group-containing polymer and a solvent onto a support. By adding an appropriate fluoroaliphatic group-containing polymer to the coating solution, it is possible to suppress repellency generated in the step of coating the coating solution on the support, the step of drying the solvent, and the step of ripening the liquid crystal. It is possible to form a uniform optically anisotropic layer in which unevenness in film thickness generated in the coating process, drying process, and alignment ripening process, and unevenness in alignment state due to temperature unevenness of hot air are reduced.

[Optically anisotropic layer]
The optically anisotropic layer containing a liquid crystalline compound is a composition (coating) containing a rod-like liquid crystalline compound or a discotic liquid crystalline compound, a fluoroaliphatic group-containing polymer, and a polymerization initiator and other additives as described later if desired. (Including liquid form) can be formed on a support.

  In the present invention, the optically anisotropic layer is preferably formed using a discotic liquid crystalline compound, and triphenylene liquid crystal is more preferably used. Discotic liquid crystalline compounds are disclosed in various documents (C. Destrade et al., Mol. Crysr. Liq. Cryst., Vol. 71, page 111 (1981); edited by The Chemical Society of Japan, Quarterly Chemical Review, No. 22, Liquid Crystal Chemistry, Chapter 5, Chapter 10 Section 2 (1994); B. Kohne et al., Angew. Chem. Soc. Chem. Comm., Page 1794 (1985); J. Zhang et al., J Am.Chem.Soc., Vol.116, page 2655 (1994)). The polymerization of discotic liquid crystalline compounds is described in JP-A-8-27284.

The discotic liquid crystalline compound preferably has a polymerizable group so that it can be fixed by polymerization. For example, a structure in which a polymerizable group is bonded as a substituent to a discotic core of a discotic liquid crystalline compound can be considered. However, when a polymerizable group is directly connected to the discotic core, the alignment state is maintained in the polymerization reaction. It becomes difficult. Therefore, a structure having a linking group between the discotic core and the polymerizable group is preferable. That is, the discotic liquid crystalline compound having a polymerizable group is preferably a compound represented by the following formula.
D (-LP) _n
In the formula, D is a discotic core, L is a divalent linking group, P is a polymerizable group, and n is an integer of 4 to 12. Preferred specific examples of the discotic core (D), the divalent linking group (L) and the polymerizable group (P) in the above formula are (D1) to (D15) described in JP-A No. 2001-4837, respectively. ), (L1) to (L25), (P1) to (P18), and the contents described in the publication can be preferably used. In addition, the discotic nematic liquid crystal phase-solid phase transition temperature of the liquid crystal compound is preferably 70 to 300 ° C, and more preferably 70 to 170 ° C.

  In the present invention, the optically anisotropic layer may be formed using a rod-like liquid crystalline compound. Examples of rod-like liquid crystalline compounds include azomethines, azoxys, cyanobiphenyls, cyanophenyl esters, benzoic acid esters, cyclohexanecarboxylic acid phenyl esters, cyanophenylcyclohexanes, cyano-substituted phenylpyrimidines, alkoxy-substituted phenylpyrimidines. , Phenyldioxanes, tolanes and alkenylcyclohexylbenzonitriles are preferably used. Not only the above low-molecular liquid crystalline compounds but also high-molecular liquid crystalline compounds can be used. It is more preferable to fix the alignment of the rod-like liquid crystal compound by polymerization. As the liquid crystal molecules, those having a partial structure capable of causing polymerization or crosslinking reaction by actinic rays, electron beams, heat, or the like are preferably used. The number of the partial structures is 1 to 6, preferably 1 to 3. As the polymerizable rod-like liquid crystalline compound, Makromol. Chem. 190, 2255 (1989), Advanced Materials 5, 107 (1993), US Pat. No. 4,683,327, US Pat. No. 5,622,648, US Pat. No. 5,770,107, International Publication No. WO95 / 22586, No. 95/24455, No. 97/00600, No. 98/23580, No. 98/52905, JP-A-1-272551, No. 6-16616, No. 7-110469, The compounds described in JP-A-11-80081 and JP-A-2001-328773 can be used.

  As a solvent used for preparing the coating solution, an organic solvent is preferably used. Examples of organic solvents include amides (eg, N, N-dimethylformamide), sulfoxides (eg, dimethyl sulfoxide), heterocyclic compounds (eg, pyridine), hydrocarbons (eg, benzene, hexane), alkyl halides (eg, , Chloroform, dichloromethane), esters (eg, methyl acetate, butyl acetate), ketones (eg, acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone), 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).

  The aligned liquid crystal compound is preferably fixed while maintaining the alignment state. The immobilization is preferably performed by a polymerization reaction of the polymerizable group (P) introduced into the liquid crystal compound. The polymerization reaction includes a thermal polymerization reaction using a thermal polymerization initiator and a photopolymerization reaction using a photopolymerization initiator. A photopolymerization reaction is preferred. Examples of the photopolymerization initiator include α-carbonyl compounds (described in US Pat. Nos. 2,367,661 and 2,367,670), acyloin ether (described in US Pat. No. 2,448,828), α-hydrocarbon substituted aromatic acyloin. Compound (described in US Pat. No. 2,722,512), polynuclear quinone compound (described in US Pat. Nos. 3,046,127 and 2,951,758), a combination of triarylimidazole dimer and p-aminophenyl ketone (US Pat. No. 3,549,367) 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).

The amount of the photopolymerization initiator used is preferably 0.01 to 20% by mass, more preferably 0.5 to 5% by mass, based on the solid content of the coating solution. Light irradiation for polymerization of discotic liquid crystalline molecules 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 retardation layer is preferably 0.1 to 10 μm, more preferably 0.5 to 5 μm, and most preferably 1 to 5 μm.

[Chiral agent]
In the present invention, it is preferable to add a chiral agent to the optically anisotropic layer in order to develop a twisted structure. A chiral agent is generally an optically active compound containing an asymmetric carbon atom. As the chiral agent, various natural or synthetic compounds containing asymmetric carbon atoms can be used. When a discotic liquid crystal compound is used for the optically anisotropic layer, a particularly preferred chiral agent is an asymmetric carbon atom in the linking group (R) of the discotic liquid crystalline molecule described in JP-A-8-50206. It is a discotic compound having a molecular structure in which atoms are introduced. Specifically, an asymmetric carbon atom is introduced into AL (an alkylene group or an alkenylene group) contained in the linking group (R). Preferred examples of AL * containing an asymmetric carbon atom are described in paragraph numbers [0033] to [0035] in JP-A-2001-100035. The chiral agent may be introduced with the same or similar polymerizable group (Q) as the discotic liquid crystalline molecule. When a polymerizable group is introduced, the chiral agent can be fixed in the optically anisotropic layer by the same or similar polymerization reaction after the discotic liquid crystal molecules are aligned. The chiral agent is used in an amount necessary and sufficient to stabilize the alignment state of the liquid crystal molecules. The magnitude of the twist amount can be obtained, for example, by an angle at which the extinction axis is extinguished from the rubbing axis (extinction angle) in a crossed Nicol state by a polarizing microscope. The extinction referred to here does not mean that transmitted light becomes zero in a strict sense, but means an angle at which the transmitted light becomes a minimum value. When the twist orientation is in the state schematically shown in FIG. 4 described above, the extinction angle is 60% to 80% of the actual twist angle.

[Alignment film]
The alignment film has a function of defining the alignment direction of the liquid crystalline molecules forming the optically anisotropic layer. The alignment film is an organic compound (eg, ω-tricosanoic acid) formed by rubbing treatment of an organic compound (preferably polymer), oblique deposition of an inorganic compound, formation of a layer having a microgroove, or Langmuir-Blodgett method (LB film). , Dioctadecylmethylammonium chloride, methyl stearylate). Furthermore, an alignment film in which an alignment function is generated by application of an electric field, application of a magnetic field, or light irradiation is also known. The alignment film is preferably formed by polymer rubbing treatment. Polyvinyl alcohol is a preferred polymer. Particularly preferred is a modified polyvinyl alcohol to which a hydrophobic group is bonded. The hydrophobic group is bonded to the main chain terminal or side chain of polyvinyl alcohol. The hydrophobic group is preferably an aliphatic group having 6 or more carbon atoms (preferably an alkyl group or an alkenyl group) or an aromatic group. When a hydrophobic group is bonded to the main chain terminal of polyvinyl alcohol, it is preferable to introduce a linking group between the hydrophobic group and the main chain terminal. Examples of the linking group include —S—, —C (CN) R ¹ —, —NR ² —, —CS—, and combinations thereof. R ¹ and R ² are each a hydrogen atom or an alkyl group having 1 to 6 carbon atoms (preferably an alkyl group having 1 to 6 carbon atoms).

When a hydrophobic group is introduced into the side chain of polyvinyl alcohol, a part of the acetyl group (—CO—CH ₃ ) of the vinyl acetate unit of polyvinyl alcohol is substituted with an acyl group having 7 or more carbon atoms (—CO—R). ³ ). R3 is an aliphatic group or aromatic group having 6 or more carbon atoms. Commercially available modified polyvinyl alcohol (eg, MP103, MP203, R1130, manufactured by Kuraray Co., Ltd.) may be used. The saponification degree of the (modified) polyvinyl alcohol used for the alignment film is preferably 80% or more. The degree of polymerization of (modified) polyvinyl alcohol is preferably 200 or more. The rubbing process is performed by rubbing the surface of the alignment film several times in a certain direction with paper or cloth. It is preferable to use a cloth in which fibers having uniform length and thickness are uniformly planted. Note that the alignment state of the liquid crystalline molecules can be maintained even if the alignment film is removed after aligning the liquid crystalline molecules of the optically anisotropic layer using the alignment film. That is, the alignment film is essential in the production of the optical compensation film in order to orient the liquid crystal molecules, but is not essential in the produced optical compensation film. When the alignment film is provided between the support and the optically anisotropic layer, it is preferable to further provide an undercoat layer (adhesive layer) between the transparent support and the alignment film.

  An alignment film is formed by using a polymer having a side chain having a crosslinkable functional group bonded to the main chain or a polymer having a crosslinkable functional group on a side chain having a function of aligning liquid crystalline molecules, and optically forming the polymer. When the anisotropic layer is formed using a composition containing a polyfunctional monomer, the polymer in the alignment film and the polyfunctional monomer in the optically anisotropic layer formed thereon can be copolymerized. . As a result, a covalent bond is formed not only between the polyfunctional monomers but also between the alignment film polymers and between the polyfunctional monomer and the alignment film polymer, and the alignment film and the optically anisotropic layer are firmly bonded. Therefore, the strength of the optical compensation sheet can be remarkably improved by forming the alignment film using a polymer having a crosslinkable functional group. The crosslinkable functional group of the alignment film polymer preferably contains a polymerizable group in the same manner as the polyfunctional monomer. Specific examples include those described in paragraphs [0080] to [0100] in JP-A-2000-155216.

  Apart from the crosslinkable functional group, the alignment film polymer can also be crosslinked using a crosslinking agent. Examples of the crosslinking agent include aldehydes, N-methylol compounds, dioxane derivatives, compounds that act by activating carboxyl groups, active vinyl compounds, active halogen compounds, isoxazole and dialdehyde starch. Two or more kinds of crosslinking agents may be used in combination. Specific examples include compounds described in paragraphs [0023] to [024] in JP-A-2002-62426. Aldehydes having high reaction activity, particularly glutaraldehyde are preferred.

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

  The alignment film can be basically formed by applying a composition containing the polymer and the crosslinking agent, which are alignment film forming materials, onto a transparent support, followed by drying by heating (crosslinking) and rubbing treatment. it can. As described above, the crosslinking reaction may be performed at any time after coating on the transparent support. When a water-soluble polymer such as polyvinyl alcohol is used as the alignment film forming material, the coating solution is preferably a mixed solvent of an organic solvent (eg, methanol) having a defoaming action and water. The ratio of water: methanol is preferably 0: 100 to 99: 1, and more preferably 0: 100 to 91: 9. Thereby, generation | occurrence | production of a bubble is suppressed and the defect of the alignment film and also the optically anisotropic layer surface reduces remarkably.

  The alignment film is preferably applied by spin coating, dip coating, curtain coating, extrusion coating, rod coating, or roll coating. A rod coating method is particularly preferable. The film thickness after drying is preferably 0.1 to 10 μm. Heating and drying can be performed at 20 ° C to 110 ° C. In order to form sufficient cross-linking, 60 ° C to 100 ° C is preferable, and 80 ° C to 100 ° C is particularly preferable. The drying time can be 1 minute to 36 hours, preferably 1 minute to 30 minutes. The pH is preferably set to an optimum value for the crosslinking agent to be used. When glutaraldehyde is used, the pH is 4.5 to 5.5, and 5 is particularly preferable.

  The alignment film is preferably provided on the transparent support. The alignment film can be obtained by rubbing the surface after crosslinking the polymer layer as described above. For the rubbing treatment, a treatment method widely adopted as a liquid crystal alignment treatment process of the LCD can be applied. That is, a method of obtaining the orientation by rubbing the surface of the orientation film in a certain direction using paper, gauze, felt, rubber, nylon, polyester fiber or the like can be used. In general, it is carried out by rubbing several times using a cloth in which fibers having a uniform length and thickness are flocked on average.

  In addition, after aligning the liquid crystalline compound using the alignment film provided on the temporary support, the liquid crystalline compound is fixed in the alignment state to form the optically anisotropic layer, and only the optically anisotropic layer is formed. May be transferred to a different support.

[Fluoroaliphatic group-containing polymer]
The optically anisotropic layer contains a fluoroaliphatic group-containing polymer. The fluoroaliphatic group-containing polymer contributes to prevention of repellency and unevenness of the optically anisotropic layer. In the conventional large-sized liquid crystal display device, there was a problem of display unevenness due to the optical film, but by using the optical compensation film of the present invention, the unevenness of the large-sized liquid crystal display device was reduced and the image quality of the large-sized liquid crystal display device was reduced. Can be improved.

  In the present invention, as the fluoroaliphatic group-containing polymer, it is preferable to use a polymer containing at least one repeating unit derived from a monomer represented by the following general formula (1).

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

  The fluoroaliphatic compound can be produced by a telomerization method (telomer method) or an oligomerization method (oligomer method). Regarding the production method of these fluoroaliphatic compounds, for example, “Synthesis and Function of Fluorine Compounds” (Supervision: Nobuo Ishikawa, Issue: CMC Co., 1987), “Chemistry of Organic Fluorines Compounds”. II "(Monograph 187, Ed by Milos Hudricky and Attila E. Pavlath, American Chemical Society 1995). The telomerization method is a method of synthesizing a telomer by radical polymerization of a fluorine-containing vinyl compound such as tetrafluoroethylene using an alkyl halide having a large chain transfer constant such as iodide as a telogen (example in Scheme-1). showed that).

  The obtained terminal iodinated telomer is usually subjected to appropriate terminal chemical modification such as (Scheme 2), and led to a fluoroaliphatic compound. These compounds are further converted into a desired monomer structure as necessary, and used for the production of a fluoroaliphatic group-containing polymer.

  The fluoroaliphatic group-containing polymer may be a copolymer containing a repeating unit derived from a monomer represented by the following general formula (2).

In the general formula (2), R ³ represents a hydrogen atom or a methyl group, Y represents a divalent linking group, R ⁴ represents a substituted or unsubstituted poly (alkyleneoxy) group, a substituted or unsubstituted carbon. A linear alkyl group having 1 to 20 carbon atoms, a branched chain having 4 to 20 carbon atoms, or a cyclic alkyl group having 3 to 20 carbon atoms is shown.

The divalent linking group represented by Y is preferably an oxygen atom, a sulfur atom or —N (R ⁵ ) —. R ⁵ is preferably a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, such as a methyl group, an ethyl group, a propyl group, or a butyl group. R ⁵ is more preferably a hydrogen atom or a methyl group. Y is more preferably an oxygen atom, —N (H) — or —N (CH ₃ ) —.

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

  In the poly (alkyleneoxy) chain, a plurality of poly (alkyleneoxy) units are one or more chain bonds (for example, —CONH—Ph—NHCO—, —S—, etc., where Ph represents a phenylene group) ) May be connected. If the chain bond has three or more valences, branched alkyleneoxy units can be obtained. The amount of the poly (alkyleneoxy) group compound is suitably 250 to 3000.

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

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

The monomer represented by the general formula (2) is particularly preferably alkyl (meth) acrylate or poly (alkyleneoxy) (meth) acrylate.
Although the specific example of the monomer shown by General formula (2) is shown next, it is not this limitation.

  Poly (alkyleneoxy) acrylate and methacrylate are commercially available hydroxypoly (alkyleneoxy) materials such as “Pluronic” (Pluronic (Asahi Denka Kogyo Co., Ltd.)), “Adeka Polyether” (Asahi Denka Kogyo ( "Carbowax" (Carbowax (Glico Products)), "Triton" (Toriton (Rohm and Haas)) and "PEG" (Daiichi Kogyo Seiyaku Co., Ltd.) Can be produced by reacting the products sold as) with acrylic acid, methacrylic acid, acrylic chloride, methacryl chloride, acrylic anhydride, etc. In addition, poly (oxyalkylenes) produced by known methods ) Diacrylate can also be used.

  The fluoroaliphatic group-containing polymer of the present invention is represented by the homopolymer of the monomer represented by the general formula (1), or the monomer represented by the general formula (1) and the general formula (2). A copolymer with a monomer (more preferably, polyalkyleneoxy (meth) acrylate, more preferably polyethyleneoxy (meth) acrylate or polypropyleneoxy (meth) acrylate) is preferable.

  The fluoroaliphatic group-containing polymer used in the present invention is a copolymer containing repeating units other than the repeating units derived from the monomers represented by the general formula (1) and the general formula (2). Also good. A preferable copolymerization ratio of the monomer copolymerizable with each of the above monomers is 20 mol% or less, more preferably 10 mol% or less in all monomers. As such a monomer, those described in pages 1 to 483 of Chapter 2 of “Polymer Handbook 2nd ed., J. Brandrup, Wiley lnterscience (1975)” can be used. For example, a compound having one addition polymerizable unsaturated bond selected from acrylic acid, methacrylic acid, acrylic esters, methacrylic esters, acrylamides, methacrylamides, allyl compounds, vinyl ethers, vinyl esters, etc. I can give you.

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

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

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

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

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

  The amount of the fluoroaliphatic group-containing monomer represented by the general formula (1) in the fluoroaliphatic group-containing polymer is preferably 5 mol% or more of the total amount of constituent monomers of the polymer, more preferably 20 The mol% or more, more preferably 30 mol% or more. The amount of the monomer represented by the general formula (2) in the fluoroaliphatic group-containing polymer of the present invention is preferably 10 mol% or more of the total amount of constituent monomers of the fluoroaliphatic group-containing polymer, more preferably It is 15-70 mol%, More preferably, it is 20-60 mol%.

The weight average molecular weight of the fluoroaliphatic group-containing polymer is preferably 3000 to 100,000, more preferably 6,000 to 80,000. The mass average molecular weight can be measured as a value in terms of polystyrene (PS) using gel permeation chromatography (GPC).
Furthermore, the content of the fluoroaliphatic group-containing polymer in the composition for forming an optically anisotropic layer is preferably 0.005 to 8% by mass, more preferably 0.01 to 1% by mass. Yes, more preferably 0.05 to 0.5% by mass. By making the addition amount of the fluoroaliphatic group-containing polymer 0.005% by mass or more, a better one can be obtained, and by making the addition amount 8% by mass or less, the coating film cannot be sufficiently dried. Or adversely affecting the performance as an optical film (for example, uniformity of retardation) can be more effectively prevented.

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

  In addition, what has a polymeric group as a substituent is preferable for the said polymer of this invention in order to fix the orientation state of a liquid crystalline compound.

  Specific examples that are preferably used in the present invention as the polymer are shown below, but the present invention is not limited to these specific examples. Here, the numerical values (numerical values such as a, b, c, d, etc.) in the formula are mass percentages indicating the composition ratio of each monomer, and Mw is TSK Gel GMHxL, TSK Gel G4000 HxL, TSK Gel G2000 HxL (whichever It is a mass average molecular weight expressed in terms of polystyrene by solvent THF and differential refractometer detection using a GPC analyzer using a column of Tosoh Corporation trade name).

  The fluoroaliphatic group-containing polymer may have a repeating unit represented by the following general formula (3). In addition to the fluoroaliphatic group-containing polymer, a polymer having a repeating unit represented by the following general formula (3) (hereinafter referred to as polymer A) may be contained. A polymer having a repeating unit represented by the following general formula (3) is preferably used not only to suppress repellency and unevenness of the liquid crystal layer but also to adjust the tilt angle of the liquid crystal compound.

In the general formula (3), R ¹¹ , R ¹² and R ¹³ each independently represents a hydrogen atom or a substituent. Q represents a carboxyl group (—COOH) or a salt thereof, a sulfo group (—SO ₃ H) or a salt thereof, a phosphonoxy group {—OP (═O) (OH) ₂ } or a salt thereof. L represents an arbitrary group selected from the following linking group group, or a divalent linking group formed by combining two or more thereof.
(Linked group group)
Single bond, —O—, —CO—, —NR ¹⁴ — (R ¹⁴ represents a hydrogen atom, an alkyl group, an aryl group, or an aralkyl group), —S—, —SO ₂ —, —P (═O) (OR ¹⁵ ) — (R ¹⁵ represents an alkyl group, an aryl group, or an aralkyl group), an alkylene group, and an arylene group.

In General Formula (3), R ¹¹ , R ¹² and R ¹³ each independently represent a hydrogen atom or a substituent selected from the substituent group exemplified below.
(Substituent group)
An alkyl group (preferably an alkyl group having 1 to 20 carbon atoms, more preferably 1 to 12 carbon atoms, particularly preferably 1 to 8 carbon atoms, such as a methyl group, an ethyl group, an isopropyl group, a tert-butyl group, n-octyl group, n-decyl group, n-hexadecyl group, cyclopropyl group, cyclopentyl group, cyclohexyl group and the like, alkenyl group (preferably having 2 to 20 carbon atoms, more preferably 2 to 12 carbon atoms, Particularly preferred are alkenyl groups having 2 to 8 carbon atoms, such as vinyl group, aryl group, 2-butenyl group and 3-pentenyl group), alkynyl groups (preferably having 2 to 20 carbon atoms, more preferred). Is an alkynyl group having 2 to 12 carbon atoms, particularly preferably 2 to 8 carbon atoms, such as propargyl group and 3-pentynyl group. An aryl group (preferably an aryl group having 6 to 30 carbon atoms, more preferably 6 to 20 carbon atoms, particularly preferably 6 to 12 carbon atoms, such as a phenyl group, a p-methylphenyl group, and a naphthyl group. Aralkyl groups (preferably 7 to 30 carbon atoms, more preferably 7 to 20 carbon atoms, particularly preferably 7 to 12 carbon atoms, such as benzyl group, phenethyl group, 3- Phenylpropyl group and the like), a substituted or unsubstituted amino group (preferably an amino group having 0 to 20 carbon atoms, more preferably 0 to 10 carbon atoms, particularly preferably 0 to 6 carbon atoms, Unsubstituted amino group, methylamino group, dimethylamino group, diethylamino group, anilino group, etc.),

An alkoxy group (preferably an alkoxy group having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, particularly preferably 1 to 10 carbon atoms, and examples thereof include a methoxy group, an ethoxy group, and a butoxy group). An alkoxycarbonyl group (preferably an alkoxycarbonyl group having 2 to 20 carbon atoms, more preferably 2 to 16 carbon atoms, particularly preferably 2 to 10 carbon atoms such as a methoxycarbonyl group and an ethoxycarbonyl group), acyloxy A group (preferably an acyloxy group having 2 to 20 carbon atoms, more preferably 2 to 16 carbon atoms, particularly preferably 2 to 10 carbon atoms such as an acetoxy group and a benzoyloxy group), an acylamino group (preferably 2-20 carbon atoms, more preferably 2-16 carbon atoms, particularly preferably 2-10 carbon atoms. A silamino group, for example, an acetylamino group, a benzoylamino group, and the like, an alkoxycarbonylamino group (preferably having 2 to 20 carbon atoms, more preferably 2 to 16 carbon atoms, and particularly preferably 2 to 12 carbon atoms). An alkoxycarbonylamino group, for example, a methoxycarbonylamino group), an aryloxycarbonylamino group (preferably having 7 to 20 carbon atoms, more preferably 7 to 16 carbon atoms, and particularly preferably 7 to 12 carbon atoms). Aryloxycarbonylamino group, for example, phenyloxycarbonylamino group and the like, sulfonylamino group (preferably having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, particularly preferably 1 to 1 carbon atoms). 12 sulfonylamino groups such as methanesulfonyl And sulfamoyl groups (preferably having 0 to 20 carbon atoms, more preferably 0 to 16 carbon atoms, and particularly preferably 0 to 12 carbon atoms, such as sulfamoyl group). Group, methylsulfamoyl group, dimethylsulfamoyl group, phenylsulfamoyl group and the like), carbamoyl group (preferably having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, and particularly preferably carbon number). 1 to 12 carbamoyl groups, for example, unsubstituted carbamoyl group, methylcarbamoyl group, diethylcarbamoyl group, phenylcarbamoyl group and the like),

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

R ¹¹ , R ¹² and R ¹³ are each independently a hydrogen atom, an alkyl group, a halogen atom (for example, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, etc.), or a group represented by -LQ described later. It is preferably a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, a chlorine atom, or a group represented by -LQ, more preferably a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. More preferably, it is particularly preferably a hydrogen atom or an alkyl group having 1 to 2 carbon atoms, most preferably R ¹² and R ¹³ are a hydrogen atom, and R ¹¹ is a hydrogen atom or a methyl group. Specific examples of the alkyl group include methyl group, ethyl group, n-propyl group, n-butyl group, sec-butyl group and the like. The alkyl group may have a suitable substituent. Examples of the substituent include a halogen atom, aryl group, heterocyclic group, alkoxyl group, aryloxy group, alkylthio group, arylthio group, acyl group, hydroxyl group, acyloxy group, amino group, alkoxycarbonyl group, acylamino group, oxycarbonyl Group, carbamoyl group, sulfonyl group, sulfamoyl group, sulfonamido group, sulfolyl group, carboxyl group and the like. The carbon number of the alkyl group does not include the carbon atom of the substituent. The same applies to the carbon number of other groups.

L represents a divalent linking group selected from the above linking group group, or a divalent linking group formed by combining two or more thereof. In the linking group group, R ^{14 in} —NR ¹⁴ — represents a hydrogen atom, an alkyl group, an aryl group or an aralkyl group, preferably a hydrogen atom or an alkyl group. R ¹⁵ in —PO (OR ¹⁵ ) — represents an alkyl group, an aryl group or an aralkyl group, and preferably an alkyl group. When R ¹⁴ and R ¹⁵ represent an alkyl group, an aryl group, or an aralkyl group, the number of carbon atoms is the same as that described in the “substituent group”. L preferably includes a single bond, —O—, —CO—, —NR ¹⁴ —, —S—, —SO ₂ —, an alkylene group, or an arylene group, and includes a single bond, —CO—, —O—. , —NR ¹⁴ —, an alkylene group or an arylene group is particularly preferable, and a single bond is most preferable. When L contains an alkylene group, the alkylene group preferably has 1 to 10 carbon atoms, more preferably 1 to 8 carbon atoms, and particularly preferably 1 to 6 carbon atoms. Specific examples of particularly preferred alkylene groups include methylene, ethylene, trimethylene, tetrabutylene, hexamethylene groups and the like. When L contains an arylene group, the carbon number of the arylene group is preferably 6 to 24, more preferably 6 to 18, and particularly preferably 6 to 12. Specific examples of particularly preferred arylene groups include phenylene and naphthalene groups. When L contains a divalent linking group (that is, an aralkylene group) obtained by combining an alkylene group and an arylene group, the carbon number of the aralkylene group is preferably 7 to 34, more preferably 7 to 26, and particularly preferably. 7-16. Specific examples of particularly preferred aralkylene groups include a phenylenemethylene group, a phenyleneethylene group, and a methylenephenylene group. The group listed as L may have a suitable substituent. Examples of such a substituent include the same substituents as those described above as the substituents for R ^{11 to} R ¹³ .
Although the specific structure of L is illustrated below, this invention is not limited to these specific examples.

  In the formula (3), Q is a carboxyl group, a salt of a carboxyl group (for example, lithium salt, sodium salt, potassium salt, ammonium salt (for example, ammonium, tetramethylammonium, trimethyl-2-hydroxyethylammonium, tetrabutylammonium, trimethyl). Benzylammonium, dimethylphenylammonium, etc.), pyridinium salts, etc.), sulfo groups, salts of sulfo groups (examples of cations forming salts are the same as those described above for carboxyl groups), phosphonoxy groups, salts of phosphonoxy groups (salts) Examples of the cation that forms are the same as those described above for the carboxyl group). A carboxyl group, a sulfo group and a phospho group are more preferable, a carboxyl group or a sulfo group is particularly preferable, and a carboxyl group is most preferable.

  Although the specific example of the monomer corresponding to the said General formula (3) contained in the said polymer A which can be used for this invention is given below, this invention is not restrict | limited at all by the following specific examples.

  The polymer A may contain one type of repeating unit represented by the general formula (3), or may contain two or more types. The polymer A may contain a repeating unit derived from the fluoroaliphatic group-containing monomer (for example, a repeating unit represented by the general formula (1)), and has two or more kinds. Also good. The polymer A may further contain other repeating units. The other repeating unit is not particularly limited, and preferred examples thereof include a repeating unit derived from a normal monomer capable of radical polymerization. Hereinafter, specific examples of monomers for deriving other repeating units will be given. The polymer A may contain a repeating unit derived from one or more monomers selected from the following monomer group.

Monomer group (1) Alkenes ethylene, propylene, 1-butene, isobutene, 1-hexene, 1-dodecene, 1-octadecene, 1-eicosene, hexafluoropropene, vinylidene fluoride, chlorotrifluoroethylene, 3, 3, 3-trifluoropropylene, tetrafluoroethylene, vinyl chloride, vinylidene chloride, etc .;
(2) Dienes 1,3-butadiene, isoprene, 1,3-pentadiene, 2-ethyl-1,3-butadiene, 2-n-propyl-1,3-butadiene, 2,3-dimethyl-1,3 -Butadiene, 2-methyl-1,3-pentadiene, 1-phenyl-1,3-butadiene, 1-α-naphthyl-1,3-butadiene, 1-β-naphthyl-1,3-butadiene, 2-chloro -1,3-butadiene, 1-bromo-1,3-butadiene, 1-chlorobutadiene, 2-fluoro-1,3-butadiene, 2,3-dichloro-1,3-butadiene, 1,1,2- Trichloro-1,3-butadiene and 2-cyano-1,3-butadiene, 1,4-divinylcyclohexane and the like;

(3) Derivatives of α, β-unsaturated carboxylic acid (3a) Alkyl acrylates Methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, sec-butyl acrylate, tert-butyl acrylate , Amyl acrylate, n-hexyl acrylate, cyclohexyl acrylate, 2-ethylhexyl acrylate, n-octyl acrylate, tert-octyl acrylate, dodecyl acrylate, phenyl acrylate, benzyl acrylate, 2-chloroethyl acrylate, 2-bromoethyl acrylate, 4-chlorobutyl acrylate, 2-cyanoethyl acrylate, 2-acetoxyethyl acrylate, methoxybenzyl Chryrate, 2-chlorocyclohexyl acrylate, furfuryl acrylate, tetrahydrofurfuryl acrylate, 2-methoxyethyl acrylate, ω-methoxypolyethylene glycol acrylate (number of added polyoxyethylene: n = 2 to 100), 3-methoxy Butyl acrylate, 2-ethoxyethyl acrylate, 2-butoxyethyl acrylate, 2- (2-butoxyethoxy) ethyl acrylate, 1-bromo-2-methoxyethyl acrylate, 1,1-dichloro-2-ethoxyethyl acrylate, glycidyl acrylate Such);

(3b) Alkyl methacrylates Methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, sec-butyl methacrylate, tert-butyl methacrylate, amyl methacrylate, n-hexyl methacrylate, cyclohexyl methacrylate, 2 -Ethylhexyl methacrylate, n-octyl methacrylate, stearyl methacrylate, benzyl methacrylate, phenyl methacrylate, allyl methacrylate, furfuryl methacrylate, tetrahydrofurfuryl methacrylate, cresyl methacrylate, naphthyl methacrylate, 2-methoxyethyl methacrylate, 3-methoxybutyl methacrylate, ω Methoxypolyethylene glycol methacrylate (number of added polyoxyethylene: n = 2 to 100), 2-acetoxyethyl methacrylate, 2-ethoxyethyl methacrylate, 2-butoxyethyl methacrylate, 2- (2-butoxyethoxy) ethyl methacrylate Glycidyl methacrylate, 3-trimethoxysilylpropyl methacrylate, allyl methacrylate, 2-isocyanatoethyl methacrylate, etc .;

(3c) Diesters of unsaturated polycarboxylic acids Dimethyl maleate, dibutyl maleate, dimethyl itaconate, dibutyl taconate, dibutyl crotonate, dihexyl crotonate, diethyl fumarate, dimethyl fumarate, etc .;

(3d) Amides of α, β-unsaturated carboxylic acids N, N-dimethylacrylamide, N, N-diethylacrylamide, Nn-propylacrylamide, N-tertbutylacrylamide, N-tertoctylmethacrylamide, N- Cyclohexylacrylamide, N-phenylacrylamide, N- (2-acetoacetoxyethyl) acrylamide, N-benzylacrylamide, N-acryloylmorpholine, diacetone acrylamide, N-methylmaleimide and the like;

(4) Unsaturated nitriles Acrylonitrile, methacrylonitrile, etc .;
(5) Styrene and its derivatives Styrene, vinyl toluene, ethyl styrene, p-tert butyl styrene, methyl p-vinyl benzoate, α-methyl styrene, p-chloromethyl styrene, vinyl naphthalene, p-methoxy styrene, p-hydroxy Methyl styrene, p-acetoxy styrene, etc .;
(6) Vinyl esters Vinyl acetate, vinyl propionate, vinyl butyrate, vinyl isobutyrate, vinyl benzoate, vinyl salicylate, vinyl chloroacetate, vinyl methoxyacetate, vinyl vinyl acetate, etc .;

(7) Vinyl ethers Methyl vinyl ether, ethyl vinyl ether, n-propyl vinyl ether, isopropyl vinyl ether, n-butyl vinyl ether, isobutyl vinyl ether, tert-butyl vinyl ether, n-pentyl vinyl ether, n-hexyl vinyl ether, n-octyl vinyl ether, n-dodecyl Vinyl ether, n-eicosyl vinyl ether, 2-ethylhexyl vinyl ether, cyclohexyl vinyl ether, fluorobutyl vinyl ether, fluorobutoxyethyl vinyl ether, etc .; and (8) other polymerizable monomers N-vinyl pyrrolidone, methyl vinyl ketone, phenyl vinyl ketone, Methoxyethyl vinyl ketone, 2-vinyl oxazoline, 2-isopropenyl oxazoline .

  The content of the repeating unit represented by the general formula (3) in the polymer A is preferably 0.1 to 50 mol% of the total amount of constituent monomers of the polymer, and is 0.2 to 40 mol%. More preferably, it is 0.3 to 30 mol%.

  The mass average molecular weight of the polymer A used in the present invention is preferably 1,000,000 or less, more preferably 500,000 or less, and further preferably 5,000 or more and 50,000 or less.

  The polymerization method of the polymer A is not particularly limited. For example, a polymerization method using a vinyl group such as cationic polymerization, radical polymerization, or anionic polymerization can be employed. Among these, radical polymerization is possible. Is particularly preferable in that it can be used for general purposes. As the polymerization initiator for radical polymerization, known compounds such as radical thermal polymerization initiators and radical photopolymerization initiators can be used, and it is particularly preferable to use radical thermal polymerization initiators. Here, the radical thermal polymerization initiator is a compound that generates radicals by heating to a decomposition temperature or higher. Examples of such radical thermal polymerization initiators include diacyl peroxide (acetyl peroxide, benzoyl peroxide, etc.), ketone peroxide (methyl ethyl ketone peroxide, cyclohexanone peroxide, etc.), hydroperoxide (hydrogen peroxide, tert. -Butyl hydroxide, cumene hydroperoxide, etc.), dialkyl peroxides (di-tert-butyl peroxide, dicumyl peroxide, dilauroyl peroxide, etc.), peroxyesters (tert-butyl peroxyacetate, tert) -Butyl peroxypivalate, etc.), azo compounds (azobisisobutyronitrile, azobisisovaleronitrile, etc.), persulfates (ammonium persulfate, sodium persulfate) And potassium persulfate) and the like. Such radical thermal polymerization initiators can be used singly or in combination of two or more.

  The radical polymerization method is not particularly limited, and an emulsion polymerization method, a suspension polymerization method, a bulk polymerization method, a solution polymerization method, and the like can be adopted. The solution polymerization, which is a typical radical polymerization method, will be described more specifically. The outlines of other polymerization methods are the same, and details thereof are described, for example, in “Polymer Science Experimental Method” edited by Polymer Society (Tokyo Kagaku Dojin, 1981).

  An organic solvent is used for solution polymerization. These organic solvents can be arbitrarily selected as long as the objects and effects of the present invention are not impaired. These organic solvents are usually organic compounds having boiling points under atmospheric pressure in the range of 50 to 200 ° C., and organic compounds that uniformly dissolve each component are preferred. Examples of preferred organic solvents include alcohols such as isopropanol and butanol; ethers such as dibutyl ether, ethylene glycol dimethyl ether, tetrahydrofuran and dioxane; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone; ethyl acetate and acetic acid And esters such as butyl, amyl acetate, and γ-butyrolactone; and aromatic hydrocarbons such as benzene, toluene, and xylene. These organic solvents can be used alone or in combination of two or more. Furthermore, a water-mixed organic solvent in which water is used in combination with the above organic solvent is also applicable from the viewpoint of the solubility of the monomer and the polymer to be produced.

  Also, the solution polymerization conditions are not particularly limited, but for example, it is preferable to heat within a temperature range of 50 to 200 ° C. for 10 minutes to 30 hours. Furthermore, in order not to deactivate the generated radicals, it is preferable to perform an inert gas purge not only during solution polymerization but also before the start of solution polymerization. Usually, nitrogen gas is suitably used as the inert gas.

  In order to obtain the polymer A in a preferable molecular weight range, a radical polymerization method using a chain transfer agent is particularly effective. As chain transfer agents, mercaptans (for example, octyl mercaptan, decyl mercaptan, dodecyl mercaptan, tert-dodecyl mercaptan, octadecyl mercaptan, thiophenol, p-nonylthiophenol, etc.), polyhalogenated alkyls (for example, carbon tetrachloride, chloroform, etc.) , 1,1,1-trichloroethane, 1,1,1-tribromooctane, etc.) and low-activity monomers (α-methylstyrene, α-methylstyrene dimer, etc.) can be used, preferably carbon These are mercaptans of 4-16. The amount of these chain transfer agents used is remarkably influenced by the activity of the chain transfer agent, the combination of the monomers, the polymerization conditions and the like, and must be precisely controlled. It is about 01 mol% to 50 mol%, preferably 0.05 mol% to 30 mol%, particularly preferably 0.08 mol% to 25 mol%. These chain transfer agents may be present in the system simultaneously with the target monomer whose degree of polymerization is to be controlled in the polymerization process, and the addition method is not particularly limited. It may be added after being dissolved in the monomer, or may be added separately from the monomer.

  In addition, the polymer A of the present invention preferably has a polymerizable group as a substituent in order to fix the alignment state of the liquid crystalline compound.

  Specific examples that are preferably used in the present invention as the polymer A are shown below, but the present invention is not limited to these specific examples. Here, the numerical values (numerical values such as a, b, c, d, etc.) in the formula are mass percentages indicating the composition ratio of each monomer, and Mw is TSK Gel GMHxL, TSK Gel G4000 HxL, TSK Gel G2000 HxL (whichever The weight average molecular weight is expressed in terms of polystyrene by solvent THF and differential refractometer detection using a GPC analyzer using a column of Tosoh Corporation's trade name).

[Other compositions of optically anisotropic layer]
Along with the liquid crystal compound, a plasticizer, a surfactant, a polymerizable monomer, and the like can be used in combination to improve the uniformity of the coating film, the strength of the film, the orientation of the liquid crystal compound, and the like. These materials are preferably compatible with the liquid crystal compound and do not inhibit the alignment.

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

  The polymer used together with the liquid crystal compound is preferably capable of thickening the coating solution. A cellulose ester can be mentioned as an example of a polymer. It is possible to suppress repelling by mixing a cellulosic polymer in the liquid crystal layer. Further, the cellulose ester functions as a tilt angle controlling agent for the liquid crystal compound. Preferable examples of the cellulose ester include those described in paragraph [0178] of JP-A No. 2000-155216. Cellulose acetate, cellulose acetate butyrate, cellulose acetate propionate, hydroxypropyl cellulose, methyl cellulose, carboxymethyl cellulose and the like are preferable. Among them, cellulose ester is preferable as the tilt angle controlling agent of the liquid crystalline compound, cellulose acetate butyrate is particularly preferable, and the degree of butyrylation of cellulose acetate butyrate is most preferably 40% or more. The addition amount of the polymer is preferably in the range of 0.1 to 10% by mass, and in the range of 0.1 to 8% by mass with respect to the liquid crystal molecules so as not to inhibit the alignment of the liquid crystal compound. It is more preferable. The discotic nematic liquid crystal phase-solid phase transition temperature of the liquid crystal compound is preferably 70 to 300 ° C, more preferably 70 to 170 ° C.

[Support]
The optically anisotropic layer is preferably produced on an alignment film formed on the support. As the support for the optically anisotropic layer, it is preferable to use a polymer film having a light transmittance of 80% or more. Examples of polymers constituting the film include cellulose esters (eg, cellulose acetate, cellulose diacetate), polyolefins (eg, norbornene polymers), poly (meth) acrylic acid esters (eg, polymethyl methacrylate), polycarbonates, and polysulfones. Is included. Commercially available polymers (for norbornene polymers, Arton (manufactured by JSR), Zeonore (manufactured by Nippon Zeon), etc.) may be used. 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 40 to 200 μm. In order to improve the adhesion between the transparent support and the layer (adhesive layer, alignment film or retardation layer) provided thereon, surface treatment (eg, glow discharge treatment, corona discharge treatment, ultraviolet (UV) treatment is applied to the transparent support. Treatment, flame treatment). An adhesive layer (undercoat layer) may be provided on the transparent support. Moreover, the average particle diameter is 10 to 100 nm in order to provide the transparent support or the long transparent support with slipperiness in the conveying process or to prevent the back surface and the surface from sticking after winding. It is preferable to use what formed the polymer layer which mixed the inorganic particle of about 5%-40% by solid content weight ratio by the application | coating or co-casting with the support body on the one side of the support body.

  The polymer film used as the transparent support is preferably a cellulose ester, and more preferably a lower fatty acid ester of cellulose. Lower fatty acid means a fatty acid having 6 or less carbon atoms. The number of carbon atoms is preferably 2 (cellulose acetate), 3 (cellulose propionate) or 4 (cellulose butyrate). Mixed fatty acid esters such as cellulose acetate propionate and cellulose acetate butyrate may be used. Of the lower fatty acid esters of cellulose, cellulose acetate is most preferred. The acetylation degree of cellulose acetate is preferably 55.0 to 62.5%, and more preferably 57.0 to 62.0%.

  The viscosity average polymerization degree (DP) of the cellulose ester is preferably 250 or more, and more preferably 290 or more. In addition, the cellulose ester preferably has a narrow molecular weight distribution of Mm / Mn (Mm is a mass average molecular weight, Mn is a number average molecular weight) by gel permeation chromatography. The value of Mm / Mn is preferably 1.0 to 5.0, more preferably 1.3 to 3.0, and most preferably 1.4 to 2.0.

  In the cellulose ester, the hydroxyl groups at the 2-position, 3-position and 6-position of cellulose are not evenly substituted but the degree of substitution at the 6-position tends to be small. In the present invention, the 6-position substitution degree of the cellulose ester is preferably about the same as or higher than the 2-position and 3-position. The ratio of the 6-position substitution degree to the total of the 2-position, 3-position and 6-position substitution degrees is preferably 30 to 40%. The ratio of the 6-position substitution degree is preferably 31% or more, particularly preferably 32% or more. The substitution degree at the 6-position is preferably 0.88 or more. The 6-position of cellulose may be substituted with an acyl group having 3 or more carbon atoms (eg, propionyl, butyryl, valeroyl, benzoyl, acryloyl) in addition to acetyl. The degree of substitution at each position can be measured by NMR. Cellulose esters having a high degree of substitution at the 6-position are described in Synthesis Example 1 described in Paragraph Nos. 0043 to 0044, Synthesis Example 2 described in Paragraph Nos. 0048 to 0049, and Paragraph Nos. 0051 to 0052. It can synthesize | combine with reference to the synthesis example 3 of these.

  A plasticizer can be added to the cellulose ester film in order to improve mechanical properties or increase the drying speed. As the plasticizer, phosphoric acid ester or carboxylic acid ester is used. Examples of phosphate esters include triphenyl phosphate (TPP) and tricresyl phosphate (TCP). Representative examples of the carboxylic acid ester include phthalic acid esters and citric acid esters. Examples of phthalic acid esters include dimethyl phthalate (DMP), diethyl phthalate (DEP), dibutyl phthalate (DBP), dioctyl phthalate (DOP), diphenyl phthalate (DPP) and diethyl hexyl phthalate (DEHP). Examples of citrate esters include triethyl O-acetylcitrate (OACTE) and tributyl O-acetylcitrate (OACTB). Examples of other carboxylic acid esters include butyl oleate, methylacetyl ricinoleate, dibutyl sebacate, and various trimellitic acid esters. Phthalate plasticizers (DMP, DEP, DBP, DOP, DPP, DEHP) are preferably used. DEP and DPP are particularly preferred. The addition amount of the plasticizer is preferably 0.1 to 25% by mass of the amount of cellulose ester, more preferably 1 to 20% by mass, and most preferably 3 to 15% by mass.

  A degradation inhibitor (eg, antioxidant, peroxide decomposer, radical inhibitor, metal deactivator, acid scavenger, amine) may be added to the cellulose ester film. The deterioration preventing agents are described in JP-A-3-199201, JP-A-51907073, JP-A-5-194789, JP-A-5-271471, and JP-A-6-107854. The addition amount of the deterioration preventing agent is preferably 0.01 to 1% by mass of the solution (dope) to be prepared, and more preferably 0.01 to 0.2% by mass. When the addition amount is less than 0.01% by mass, the effect of the deterioration preventing agent is hardly recognized. When the addition amount exceeds 1% by mass, bleed-out (bleeding) of the deterioration preventing agent to the film surface may be observed. Examples of particularly preferred deterioration inhibitors include butylated hydroxytoluene (BHT) and tribenzylamine (TBA). Furthermore, a very small amount of dye may be added to prevent light piping. From the viewpoint of transmittance, it is preferable to adjust the type and amount so that the transmittance of light having a wavelength of 420 nm is 50% or more. The added amount of the dye is preferably 0.01 ppm to 1 ppm.

In order to control the retardation value, a retardation increasing agent can be added to the cellulose ester film. It is preferable to adjust the Re value of the cellulose ester film to a range of 0 to 70 nm and the Rth value to a range of 10 to 400 nm. In addition, it is preferable that the birefringence ((DELTA) n: nx-ny) of a cellulose-ester film exists in the range of 0-0.02. The birefringence {(nx + ny) / 2−nz} in the thickness direction of the cellulose ester film is preferably in the range of 0 to 0.04.

  The retardation increasing agent is preferably an aromatic compound having at least two aromatic rings. The retardation increasing agent is preferably used in the range of 0.01 to 20 parts by mass, more preferably in the range of 0.05 to 15 parts by mass, with respect to 100 parts by mass of the cellulose ester. Most preferably, it is used in the range of 1 to 10 parts by mass. Two or more aromatic compounds may be used in combination. The aromatic ring of the aromatic compound includes an aromatic heterocyclic ring in addition to the aromatic hydrocarbon ring. The aromatic hydrocarbon ring is particularly preferably a 6-membered ring (that is, a benzene ring).

  An aromatic heterocycle is an unsaturated heterocycle. The aromatic heterocycle is preferably a 5-membered ring, 6-membered ring or 7-membered ring, more preferably a 5-membered ring or 6-membered ring. Aromatic heterocycles generally have the most double bonds. As the hetero atom, a nitrogen atom, an oxygen atom and a sulfur atom are preferable, and a nitrogen atom is particularly preferable. Examples of aromatic heterocycles include furan ring, thiophene ring, pyrrole ring, oxazole ring, isoxazole ring, thiazole ring, isothiazole ring, imidazole ring, pyrazole ring, furazane ring, triazole ring, pyran ring, pyridine ring , Pyridazine ring, pyrimidine ring, pyrazine ring and 1,3,5-triazine ring. As the aromatic ring, benzene ring, furan ring, thiophene ring, pyrrole ring, oxazole ring, thiazole ring, imidazole ring, triazole ring, pyridine ring, pyrimidine ring, pyrazine ring and 1,3,5-triazine ring are preferable, More preferred are a benzene ring and a 1,3,5-triazine ring. It is particularly preferred that the aromatic compound has at least one 1,3,5-triazine ring.

  The number of aromatic rings contained in the aromatic compound is preferably 2 to 20, more preferably 2 to 12, further preferably 2 to 8, and most preferably 2 to 6. . The bonding relationship between two aromatic rings can be classified into (a) when a condensed ring is formed, (b) when directly linked by a single bond, and (c) when linked via a linking group (for aromatic rings). , Spiro bonds cannot be formed). The connection relationship may be any of (a) to (c). The retardation increasing agent is described in the pamphlets of WO01 / 88574 and WO00 / 2619, and JP-A 2000-1111914 and 2000-275434.

  The cellulose ester film can be produced by a solvent cast method using a solution containing cellulose ester and other components as a dope. The dope is cast on a drum or band and the solvent is evaporated to form a film. It is preferable to adjust the concentration of the dope before casting so that the solid content is 10 to 40% by mass. The solid content is more preferably 18 to 35% by mass. Two or more dopes can be cast. The surface of the drum or band is preferably finished in a mirror state. The casting and drying methods in the solvent casting method are described in U.S. Pat. No. 736892, JP-B Nos. 45-4554, 49-5614, JP-A-60-176834, No. 60-203430, and No. 62-1115035.

  The dope is preferably cast on a drum or band having a surface temperature of 10 ° C. or less. After casting, it is preferable to dry it by applying air for 2 seconds or more. Then, the method can be employed in which the obtained film is peeled off from the drum or band and further dried with high-temperature air at different temperatures of 100 to 160 ° C. to evaporate the residual solvent (described in Japanese Patent Publication No. 5-17844). . According to this method, it is possible to shorten the time from casting to stripping. In order to carry out this method, it is necessary for the dope to gel at the surface temperature of the drum or band during casting. When casting a plurality of cellulose ester solutions, a solution is prepared by casting a solution containing cellulose ester from a plurality of casting openings provided at intervals in the traveling direction of the support, and laminating them. (Japanese Patent Laid-Open Nos. 61-158414, 1-122419, and 11-198285). A film can also be produced by casting a cellulose ester solution from two casting ports (Japanese Patent Publication Nos. 60-27562, 61-94724, 61-947245, 61-104413, No. 61-158413 and JP-A-6-134933). Employs a method of casting a cellulose ester film (described in JP-A-56-162617) by wrapping a flow of a high-viscosity cellulose ester solution with a low-viscosity cellulose ester solution and simultaneously extruding the high-viscosity and low-viscosity cellulose ester solutions. May be.

  The retardation of the cellulose ester film can be further adjusted by a stretching treatment. The draw ratio is preferably in the range of 3 to 100%. Tenter stretching is preferred. In order to control the slow axis with high accuracy, it is preferable to make the difference between the left and right tenter clip speeds and the separation timing as small as possible. The stretching process is described on page 37, line 8 to page 38, line 8 of the pamphlet of WO 01/88574.

  The cellulose ester film is preferably subjected to a surface treatment. Examples of the surface treatment include corona discharge treatment, glow discharge treatment, flame treatment, acid treatment, alkali treatment, and ultraviolet irradiation treatment. From the viewpoint of maintaining the flatness of the film, the temperature of the cellulose ester film in the surface treatment is preferably Tg (glass transition temperature) or lower, specifically 150 ° C. or lower.

  The surface treatment of the cellulose ester film is particularly preferably an acid treatment or an alkali treatment, that is, a saponification treatment for the cellulose ester. Alkali treatment is most preferred. Hereinafter, the alkali saponification treatment will be specifically described as an example. The alkali treatment is preferably performed in a cycle in which the film surface is immersed in an alkali solution, neutralized with an acidic solution, washed with water and dried. The alkaline solution is preferably a potassium hydroxide solution or a sodium hydroxide solution. The specified concentration of hydroxide ions is preferably in the range of 0.1 to 3.0N, and more preferably in the range of 0.5 to 2.0N. The alkaline solution temperature is preferably in the range of room temperature to 90 ° C, more preferably in the range of 40 to 70 ° C.

  The film surface energy after the surface treatment is preferably 55 mN / m or more, and more preferably in the range of 60 to 75 mN / m. The surface energy of a solid can be determined by a contact angle method, a wet heat method, and an adsorption method as described in “Basics and Applications of Wetting” (issued by Realize 1989.12.10). In the case of the cellulose ester film, it is preferable to use a contact angle method. Specifically, two types of solutions having known surface energies are dropped onto a cellulose ester film, and at the intersection between the surface of the droplet and the film surface, the angle formed by the tangent line drawn on the droplet and the film surface The surface angle of the film can be calculated by defining the angle containing the droplet as the contact angle. An undercoat layer (described in JP-A-7-333433) may be provided on the cellulose ester film.

[Polarizer]
The polarizing plate of this invention has a polarizing film and the said optically anisotropic layer. The polarizing film may have a pair of protective films that sandwich the polarizing film, and at least one of the pair of protective films may also serve as a support for the optically anisotropic layer. The kind of protective film 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. Commercially available polymers (for norbornene polymers, Arton (manufactured by JSR), Zeonore (manufactured by Nippon Zeon), etc.) may be used. Examples of the polarizing film include an iodine polarizing film, a dye polarizing film using a dichroic dye, and a polyene polarizing film. The iodine-based polarizing film and the dye-based polarizing film are generally produced using a polyvinyl alcohol (hereinafter referred to as PVA) film.

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

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

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

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

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

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

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

  Typical examples of dichroic molecules include C.I. Eye. direct. Yellow 12, sea. Eye. direct. Orange 39, sea. Eye. direct. Orange 72, sea. Eye. direct. Red 28, Sea. Eye. direct. Red 39, Sea. Eye. direct. Red 79, Sea. Eye. direct. Red 81, Sea. Eye. direct. Red 83, Sea. Eye. direct. Red 89, Sea. Eye. direct. Violet 48, C.I. Eye. direct. Blue 67, Sea. Eye. direct. Blue 90, Sea. Eye. direct. Green 59, Sea. Eye. Acid. Red 37 and the like, and further, JP-A-1-161202, JP-A-1-172906, JP-A-1-172907, JP-A-1-183602, JP-A-200048105, JP-A-200065205, JP-A-7-0065. Examples thereof include dyes described in each publication of Japanese Patent No. 261024. In particular, Sea. Eye. direct. Red 28 (Congo Red) has long been known as preferred for this application. These dichroic molecules are used as free acids or alkali metal salts, ammonium salts, and salts of amines.

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

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

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

[Liquid Crystal Display]
The optical compensation film of the present invention is preferably used for optical compensation for a liquid crystal cell in which liquid crystal is twisted and aligned, for example, a TN mode liquid crystal cell. FIG. 2 is a schematic diagram of some basic configuration examples of a transmissive liquid crystal display device including the optical compensation film of the present invention.
The transmissive liquid crystal display device shown in FIG. 2 includes, in order from the backlight (BL) side, a transparent protective film (1a), a polarizing film (2a), a transparent support (3a), an optically anisotropic layer (4a), and liquid crystal. Cell lower substrate (5a), rod-shaped liquid crystal layer (6), liquid crystal cell upper substrate (5b), optical anisotropic layer (4b), transparent support (3b), polarizing film (2b), and transparent protective film (1b). The transparent support and the optically anisotropic layer (3a, 4a and 4b, 3b) constitute the optical compensation film of the present invention. And a transparent protective film, a polarizing film, a transparent support body, and an optically anisotropic layer (1a-4a and 4b-1b) comprise the elliptically polarizing plate of this invention.

  The TN mode liquid crystal cell is most frequently used as a color TFT liquid crystal display device, and is described in many documents. The alignment state in the liquid crystal cell in the TN mode black display is an alignment state in which the rod-like liquid crystalline molecules rise at the center of the cell and the rod-like liquid crystalline molecules lie in the vicinity of the cell substrate. In a normally white mode liquid crystal display device, in a non-driving state in which no driving voltage is applied to the electrodes, the liquid crystal molecules in the liquid crystal cell are aligned substantially parallel to the substrate surface, and the alignment direction is 90 to 90 mm between the upper and lower substrates. When the applied voltage is increased, the liquid crystal molecules are configured to gradually stand in the direction perpendicular to the substrate surface while eliminating the twist.

  The product Δn · d of the thickness d (μm) of the liquid crystal layer and the refractive index anisotropy Δn is preferably 0.2 to 0.5 μm. The twist angle (twist angle) of the liquid crystal layer is generally twisted clockwise from the light source side toward the display observation side as viewed from the observation side, and the optimum value is in the vicinity of 90 ° (85 ° to 95 °). . In these ranges, since the white display luminance is high and the black display luminance is low, a bright and high-contrast display device can be obtained. Note that these optimum values are values in the transmission mode, and in the reflection mode, the optical path in the liquid crystal cell is doubled. Therefore, the optimum Δnd value is about a half of the above value. In addition, the optimum twist angle is 30 ° to 70 °.

  In the transmissive liquid crystal display device shown in FIG. 2, the two polarizing films 2a and 2b are arranged with their polarization axes substantially orthogonal.

  The liquid crystal display device of the present invention is not limited to the configuration shown in FIG. 2, and may include other members. For example, a color filter may be disposed between the liquid crystal cell and the polarizing film. A backlight using a cold cathode or a hot cathode fluorescent tube, or a light emitting diode, a field emission element, or an electroluminescent element as a light source can be disposed. The liquid crystal display device of the present invention may be a transflective type in which a reflective portion and a transmissive portion are provided in one pixel of the display device in order to achieve both transmission and reflection modes.

  The liquid crystal display device of the present invention includes an image direct view type, an image projection type, and a light modulation type. The present invention is particularly effective when applied to an active matrix liquid crystal display device using three-terminal or two-terminal semiconductor elements such as TFT and MIM. Of course, an embodiment applied to a passive matrix liquid crystal display device is also effective.

  The operation of the liquid crystal display device having the configuration shown in FIG. 2 will be described. In this embodiment, an example in which active driving is performed using a nematic liquid crystal having positive dielectric anisotropy will be described. A liquid crystal having positive dielectric anisotropy, refractive index anisotropy Δn = 0.0854 (589 nm, 20 ° C.) and dielectric anisotropy Δε = + 8.5 is sealed between the upper and lower substrates 6a and 6b. The alignment control of the liquid crystal layer can be controlled by the surface properties and rubbing axes of the alignment films formed on the inner surfaces of the upper and lower substrates 6a and 6b. The director indicating the alignment direction of the liquid crystal molecules, that is, the so-called tilt angle is preferably about 3 °. The rubbing direction is applied to the upper and lower substrates 6a and 6b in directions orthogonal to each other, and the magnitude of the tilt angle can be controlled by the strength and the number of times of rubbing. The alignment film is preferably formed by applying and baking a polyimide film. The magnitude of the twist angle of the liquid crystal layer is determined by the crossing angle of the upper and lower substrates in the rubbing direction and the chiral agent added to the liquid crystal material. For example, to make the twist angle 90 °, it is preferable to add a chiral agent with a pitch of about 60 μm. The thickness d of the liquid crystal layer may be about 5 μm, for example. The liquid crystal material LC to be used is not particularly limited as long as it is a nematic liquid crystal. As the dielectric anisotropy Δε is larger, the driving voltage can be reduced. The smaller the refractive index anisotropy Δn, the thicker the liquid crystal layer (gap) can be, and the gap variation can be reduced. In addition, a larger Δn can reduce the cell gap and enable high-speed response.

  The polarizing axis of the upper polarizing film 2b and the polarizing axis of the lower polarizing film 2a are stacked approximately orthogonally, and the polarizing axis of the upper polarizing film 2b of the liquid crystal cell and the rubbing direction of the upper substrate 6b are approximately orthogonally crossed, and the lower polarizing film 2a The polarizing axis and the rubbing direction of the lower substrate 6a are laminated so as to be approximately orthogonal to each other. A transparent electrode (not shown) is formed inside the alignment film of each of the upper substrate 6b and the lower substrate 6a. In a non-driving state in which no driving voltage is applied to the electrodes, the liquid crystal molecules in the liquid crystal cell are placed on the substrate surface. As a result, the polarization state of light passing through the liquid crystal panel is propagated along the twisted structure of the liquid crystal molecules, and the polarization plane is rotated by 90 ° and emitted. That is, the liquid crystal display device realizes white display in a non-driven state. In contrast, in the driving state, the liquid crystal molecules are aligned in a direction that forms an angle with respect to the substrate surface, and the light that has passed through the lower polarizing film 2a passes through the liquid crystal layer 7 while maintaining the polarization state. It is blocked by the polarizing film 2b. In other words, a black display is obtained in the driving state. Since this liquid crystal display device includes the optical compensation film of the present invention, the gradation inversion phenomenon that occurs depending on the viewing direction is reduced, and the viewing angle is improved. As a result, the driving effective voltage necessary to obtain a desired black transmittance can be reduced, and the angle at which the liquid crystal molecules stand in the liquid crystal cell, particularly the TN mode liquid crystal cell, is reduced. As a result, the angle at which gradation inversion occurs can be set to an angle larger than the normal and not recognizable only from the lower side. The liquid crystal display device of the present invention is preferably a drive effective voltage that achieves the black transmittance when the drive effective voltage that achieves the black transmittance desired as the liquid crystal display device is V1 when the optical compensation film of the present invention is removed. However, it is preferably 5% or more and less than 60% smaller than V1, and more preferably 10% or more and less than 50%.

  The features of the present invention will be described more specifically with reference to examples and comparative examples. The materials, amounts used, ratios, processing details, processing procedures, and the like shown in the following examples can be changed as appropriate without departing from the spirit of the present invention. Therefore, the scope of the present invention should not be construed as being limited by the specific examples shown below.

[Example 1]
(Production of support)
The following composition was put into a mixing tank and stirred while heating to 30 ° C. to dissolve each component to prepare a cellulose acetate solution.
Cellulose acetate solution composition (parts by weight) Inner layer Outer layer Cellulose acetate with 60.9% acetylation 100 parts by weight 100 parts by weight Triphenyl phosphate (plasticizer) 7.8 parts by weight 0.8 parts by weight Biphenyl diphenyl phosphate (plasticizer) 3.9 parts by mass 3.9 parts by mass Methylene chloride (first solvent) 293 parts by mass 314 parts by mass Methanol (second solvent) 71 parts by mass 76 parts by mass 1-butanol (third solvent) 1.5 parts by mass 6 parts by mass Silica fine particles (AEROSIL R972, manufactured by Nippon Aerosil Co., Ltd.)
0 parts by mass 0.8 parts by mass The following retardation increasing agent 1.4 parts by mass 0 parts by mass

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

The obtained cellulose acetate film had a width of 1340 mm and a thickness of 80 μm. Using an ellipsometer (M-150, manufactured by JASCO Corporation), the in-plane retardation value (Re) at a wavelength of 630 nm was measured and found to be 8 nm. Further, the retardation value (Rth) in the thickness direction at a wavelength of 630 nm was measured and found to be 93 nm.
The 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 dried. The surface energy of this film was determined by the contact angle method and found to be 63 mN / m.
On this film, an alignment film coating solution having the following composition was coated at a coating amount of 28 ml / m ² with a # 16 wire bar coater. Drying was performed with warm air of 60 ° C. for 60 seconds, and further with warm air of 90 ° C. for 150 seconds.

Alignment film coating solution composition Modified polyvinyl alcohol 10 parts by weight Water 371 parts by weight Methanol 119 parts by weight Glutaraldehyde (crosslinking agent) 0.5 parts by weight

  The alignment film was rubbed in a direction parallel to the slow axis (measured at a wavelength of 632.8 nm) of the cellulose acetate film.

(Formation of optically anisotropic layer A)
Composition of optically anisotropic layer A The following discotic liquid crystal compound 91.0 parts by mass Ethylene oxide modified trimethylolpropane triacrylate (V # 360, manufactured by Osaka Organic Chemical Co., Ltd.) 9.0 parts by mass The following chiral agent 0.1 part by mass Fluoroaliphatic group-containing polymer (X-11) 0.4 part by weight Photopolymerization initiator (Irgacure 907, manufactured by Ciba Geigy) 3.0 parts by mass Sensitizer (Kayacure DETX, Nippon Kayaku ( 1.0 mass part)

  The composition of the optically anisotropic layer A is dissolved in 194 parts by mass of methyl ethyl ketone to form a coating solution, which is continuously coated on the alignment film with a # 3.4 wire bar, at 130 ° C. The discotic liquid crystalline compound was aligned by heating for 2 minutes. Next, UV irradiation was performed for 1 minute using a 120 W / cm high-pressure mercury lamp at 100 ° C. to polymerize the discotic liquid crystalline compound. Then, it stood to cool to room temperature. Thus, the optical compensation film 1 with an optically anisotropic layer was produced. The thickness of the formed optically anisotropic layer was 1.9 μm. Moreover, there was no repellency (part in which the liquid crystal layer was not formed on the alignment film) in the optical anisotropic layer. The Re retardation value of only the optically anisotropic layer when measured at a wavelength of 546 nm was 34 nm. Further, the average inclination angle β between the disk surface of the liquid crystal molecules and the transparent support surface was 38 °, and it was confirmed that the liquid crystal molecules were hybrid aligned. When an optically anisotropic layer prepared separately using a glass plate as a support was observed with a crossed Nicol arrangement using a polarizing microscope, the direction of twist was directed from the interface with the alignment film toward the air interface, and was observed from the air interface. It was twisted clockwise and the twist angle φ determined from the extinction position was 5 °. When the polarizing plate was placed in a crossed Nicol arrangement and the unevenness of the obtained optical compensation film was observed, the unevenness was not detected even when viewed from the front and the direction inclined to 60 ° from the normal.

[Example 2]
An optical compensation film 2 was produced in the same manner as in Example 1 except that the optically anisotropic layer B was formed using the following composition instead of the optically anisotropic layer A in Example 1. The thickness of the formed optically anisotropic layer was 1.9 μm. Moreover, there was no repellency (part in which the liquid crystal layer was not formed on the alignment film) in the optical anisotropic layer. The Re retardation value of only the optically anisotropic layer when measured at a wavelength of 546 nm was 42 nm. The average tilt angle β between the disk surface of the liquid crystal molecules and the transparent support surface was 44 °, and it was confirmed that the liquid crystal molecules were hybrid aligned. When an optically anisotropic layer prepared separately using a glass plate as a support was observed with a crossed Nicol arrangement using a polarizing microscope, the direction of twist was directed from the interface with the alignment film toward the air interface, and was observed from the air interface. It was twisted clockwise and the twist angle φ determined from the extinction position was 5 °. When the polarizing plate was placed in a crossed Nicol arrangement and the unevenness of the obtained optical compensation film was observed, the unevenness was not detected even when viewed from the front and the direction inclined to 60 ° from the normal.
Composition of optically anisotropic layer B The following discotic liquid crystal compound 91.0 parts by mass Ethylene oxide-modified trimethylolpropane triacrylate (V # 360, manufactured by Osaka Organic Chemical Co., Ltd.) 9.0 parts by mass The above chiral agent 0.1 part by mass Fluoroaliphatic group-containing polymer (X-11) 0.4 part by mass Cellulose acetate butyrate 0.85 part by mass (CAB531-1, manufactured by Eastman Chemical Co., Ltd.)
0.85 parts by mass of the following polymer Photopolymerization initiator (Irgacure 907, manufactured by Ciba Geigy) 3.0 parts by mass Sensitizer (Kayacure DETX, manufactured by Nippon Kayaku Co., Ltd.) 1.0 part by mass

[Comparative Example 1]
In Example 1, the optical compensation film 3 was produced in the same manner as in Example 1 except that the fluoroaliphatic group-containing polymer (X-11) was not added to the composition of the optically anisotropic layer A. did. The optically anisotropic layer had 6 repellents (average diameter of about 5 mm) per 100 cm ² . Further, when the polarizing plate was arranged in a crossed Nicol arrangement and the obtained optical compensation film was observed from the front and a direction inclined to 60 ° from the normal line, unevenness was detected.

[Comparative Example 2]
In the above Example 2, an optical compensation film 4 was produced in the same manner as in Example 2 except that the fluoroaliphatic group-containing polymer (X-11) was not added to the composition of the optically anisotropic layer B. The optically anisotropic layer had 3 repels (average diameter of about 3 mm) per 100 cm ² . Further, when the polarizing plate was arranged in a crossed Nicol arrangement and the obtained optical compensation film was observed from the front and a direction inclined to 60 ° from the normal line, unevenness was detected.

(Preparation of polarizing plate)
PVA having an average polymerization degree of 4000 and a saponification degree of 99.8 mol% was dissolved in water to obtain a 4.0% aqueous solution. This solution was band-cast using a die having a taper and dried to form a film so that the width before stretching was 110 mm, the thickness was 120 μm at the left end, and 135 μm at the right end.
The film is peeled off from the band, stretched obliquely in the direction of 45 degrees in a dry state, and immersed in an aqueous solution of 0.5 g / L iodine and 50 g / L potassium iodide for 1 minute at 30 ° C., and then 100 g boric acid. / L, potassium iodide 60 g / L in an aqueous solution at 70 ° C. for 5 minutes, further washed in a water washing tank at 20 ° C. for 10 seconds, and then dried at 80 ° C. for 5 minutes to obtain an iodine polarizing film. The polarizing film had a width of 660 mm and a thickness of 20 μm on both sides.

  Optical compensation films 1 to 4 were attached to one side of the polarizing film using a polyvinyl alcohol-based adhesive. At this time, the support surface (surface opposite to the surface on which the optically anisotropic layer was formed) was pasted so as to be in contact with the polarizing film. Further, a saponification treatment was performed on a triacetyl cellulose film (TD80UF, manufactured by Fuji Photo Film Co., Ltd.) having a thickness of 80 μm, and was pasted on the opposite side of the polarizing film using a polyvinyl alcohol-based adhesive. The angle between the absorption axis of the polarizing film and the rubbing direction of the optical compensation film was bonded to be 2 °. At this time, the angle between the orientation of the axis projected on the plane of the optically anisotropic layer with the director of the discotic liquid crystal compound on the side close to the polarizing film and the absorption axis of the polarizing film is 2 °, and the absorption of the polarizing film The axis was set to be between the azimuths of the axis projected on the plane of the optically anisotropic layer by the director of the discotic liquid crystal compound on the side close to and far from the polarizing film. In this manner, polarizing plates 1 to 4 each having the optical compensation films 1 to 4 on one side were prepared.

(Production of liquid crystal display device)
A pair of polarizing plates provided in a liquid crystal display device (AQUAS LC20C1S, manufactured by Sharp Corporation) using a TN type liquid crystal cell is peeled off. Liquid crystal display devices 1 to 5 were prepared by attaching them one by one to the observer side and the backlight side through an adhesive so as to be on the liquid crystal cell side. Note that the transmission axis of the polarizing plate on the observer side and the transmission axis of the polarizing plate on the backlight side were arranged to be in the O mode.
About the produced liquid crystal display devices 1-5, the black display and the halftone display were performed on the whole screen, and the nonuniformity and the repellency were observed from the direction inclined to 60 degrees from the front and the normal line. Moreover, the contrast ratio in a front direction was calculated | required using the measuring machine (EZ-Contrast160D, ELDIM company make). The results are shown in Table 1.

[Reference example]
A polarizing plate was produced in the same manner as in Example 1 except that the optical compensation film 1 was bonded so that the angle formed by the absorption axis of the polarizing film and the rubbing direction of the optical compensation film was 0 °. In the produced polarizing plate, the angle formed by the orientation of the axis projected on the plane of the optically anisotropic layer with the director of the discotic liquid crystal compound closer to the polarizing film and the absorption axis of the polarizing film was 0 °. When a liquid crystal display device was similarly produced using this polarizing plate and evaluated in the same manner, the contrast in the front direction was 230, which was inferior to that of Example 1.

It is the schematic diagram which expanded and showed the twisted hybrid orientation of a discotic liquid crystalline molecule about an example of the optical compensation film of this invention. It is a schematic diagram which shows the basic structural example of the transmissive liquid crystal display device of this invention.

Explanation of symbols

1a, 1b, 1c Transparent protective film 2a, 2b Polarizing film 3, 3a, 3b Transparent support 4, 4a, 4b Optically anisotropic layer 5a, 5b Upper and lower substrates of liquid crystal cell 6 Bar-shaped liquid crystal layer BL Backlight d Disk-shaped liquid crystal Molecule de long axis of discotic liquid crystalline molecules

Claims (8)

An optical compensation film including at least one optically anisotropic layer formed by fixing an alignment state of a liquid crystal compound, wherein the liquid crystal compound is formed by a director of molecules and a layer plane. The optically anisotropic layer has a hybrid orientation in which the angle changes in the depth direction of the layer and a twisted orientation in which the orientation of the axis of the director projected on the layer plane changes. Is an optical compensation film containing a fluoroaliphatic group-containing polymer. The optical compensation film according to claim 1, wherein the fluoroaliphatic group-containing polymer is a polymer containing at least one repeating unit derived from a monomer represented by the following general formula (1).

(In general formula (1), R ¹ represents a hydrogen atom or a methyl group, X represents an oxygen atom, a sulfur atom or —N (R ² ) —, H ^f represents a hydrogen atom or a fluorine atom, R ² Represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, m represents an integer of 1 to 6, and n represents an integer of 2 to 4.) The optical compensation film according to claim 2, wherein in the general formula (1), H ^f is a fluorine atom. The optical compensation film according to claim 1, wherein the liquid crystal compound is a discotic liquid crystal compound. Furthermore, the optical compensation film of any one of Claims 1-4 which has a support body which supports the said optically anisotropic layer. The optical compensation film according to claim 5, wherein the support is a cellulose ester film. A polarizing plate in which the optical compensation film according to claim 1 and a polarizing film are laminated. A liquid crystal display device comprising the optical compensation film according to claim 1, or the polarizing plate according to claim 7.

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