JP4806992B2 - Liquid crystal display - Google Patents

Description

    The present invention relates to a liquid crystal display device. More specifically, the present invention relates to a liquid crystal display device that is excellent in antireflection, scratch resistance and durability, and has a uniform display and high contrast in a wide range of observation angles.

Liquid crystal display devices have features such as high image quality, thinness, light weight, and low power consumption, and are widely used in televisions, personal computers, car navigation devices, and the like. Until now, when the screen of the liquid crystal display device is observed from an oblique direction, the brightness, color, contrast, and the like have changed greatly, and there has been a problem that the screen becomes difficult to see.
In order to solve this problem, a method for improving the design of the liquid crystal cell itself has been studied, and one of them is an in-plane switching (hereinafter also referred to as IPS) mode liquid crystal display device (Patent Document 1). According to this method, the viewing angle is improved as compared with liquid crystal display devices of other modes. However, in this method, although the narrow viewing angle due to the liquid crystal molecules in the liquid crystal cell is slightly eliminated, the arrangement of the polarizing plates may deviate from the crossed Nicols arrangement depending on the observation angle, which causes light leakage. Occurs and the viewing angle decreases. In addition, there is still room for improvement in the narrow viewing angle due to the liquid crystal molecules in the liquid crystal cell. For this reason, attempts have been made to improve the viewing angle by adding optical compensation means to the IPS mode liquid crystal display device.
For example, in an IPS mode liquid crystal display device, an optical compensation sheet that is an optical anisotropic plate is disposed between a liquid crystal cell and a polarizing plate, the optical compensation sheet has an optically negative uniaxiality, and A liquid crystal display device whose optical axis is parallel to the sheet surface has been proposed (Patent Document 2).
On the other hand, from an attempt to improve the reduction in contrast of the display screen due to the surface reflection of the polarizing plate used in a liquid crystal display device or the like, a siloxane oligomer having a specific molecular weight and a fluoroalkyl structure having a specific molecular weight on the surface of the polarizing plate and A polarizing plate having improved antireflection properties by providing an antireflection film comprising a curable resin composition containing a fluorine compound containing a polysiloxane structure has been reported (Patent Document 3). However, the polarizing plate of Patent Document 3 is still insufficient for obtaining a liquid crystal display device having a uniform and high contrast in a wide range of observation angles when mounted on an IPS liquid crystal display device, and further improvement is required. It was done.

JP 7-261152 A Japanese Patent Application Laid-Open No. 10-054982 JP 2004-167827 A

    An object of the present invention is to provide a liquid crystal display device that is excellent in antireflection properties, scratch resistance and durability, and can provide a high contrast with a uniform display in a wide range of observation angles.

As a result of intensive studies to solve the above-mentioned problems, the present inventors have found that in an IPS mode liquid crystal display device, two main elements in the plane of k optical anisotropic plates (k is an integer of 2 or more). When the total refractive index is less than or equal to twice the total main refractive index in the thickness direction, and the optical anisotropic plate and the liquid crystal cell are stacked, and light having a wavelength of 550 nm is vertically incident the retardation _{R 0,} close to the ratio _R 40 / _{R 0} is 1 and retardation _{R 40} when light of wavelength 550nm is incident at an angle inclined 40 degrees from the normal to the main axis direction, and the exit side polarizing A display device having an antireflection plate on the observation side of the child, and the antireflection plate having a low refractive index layer made of a cured film of a composition containing a specific component has good black display quality when viewed from any direction. Found that it is homogeneous and has high contrast, This has led to the completion of the present invention based on the findings.
That is, the present invention
(1) There are k (k is an integer of 2 or more) optical differences between a pair of polarizers composed of an output-side polarizer and an incident-side polarizer whose absorption axes are substantially perpendicular to each other. An IPS mode liquid crystal display device having a square plate and a liquid crystal cell,
The number of the optical anisotropic plate is i, the main refractive index in the surface of the i-th optical anisotropic plate is n _ix , n _iy (where n _ix > n _iy ), and the main refractive index in the thickness direction. _Where n _iz is
(Σn _ix + Σn _iy ) / 2 ≦ Σn _iz
(Where Σ represents the sum of i = 1 to k),
In the optical laminated plate (O) formed by laminating the optical anisotropic plate and the liquid crystal cell, the retardation when light having a wavelength of 550 nm is perpendicularly incident is R ₀ , and the light having a wavelength of 550 nm is from the normal to the main axis direction. When the retardation when incident at an angle of 40 degrees is R ₄₀ ,
0.90 <R ₄₀ / R ₀ <1.10
And satisfy the relationship
An antireflection plate is provided on the observation side of the output side polarizer,
The antireflection plate is a hollow particle (A) having a particle size of 5 to 2000 nm or less, a siloxane oligomer (B) having a (meth) acryloyl group and a fluoroalkyl group, and an acrylate compound having a (meth) acryloyl group (C A liquid crystal display device comprising a low refractive index layer comprising a cured film of a composition comprising
(2) The liquid crystal display device according to (1), wherein a refractive index of the low refractive index layer is 1.40 or less,
(3) The liquid crystal display device according to (1) or (2), wherein at least one of the optical anisotropic plates is a layer containing a resin having a negative intrinsic birefringence.
(4) The liquid crystal display device according to (1) or (2), wherein at least one of the optical anisotropic plates is a layer containing discotic liquid crystal molecules or lyotropic liquid crystal molecules,
(5) The liquid crystal display device according to (1) or (2), wherein at least one of the optical anisotropic plates is a layer containing a photoisomerization substance,
Is to provide.

    The liquid crystal display device of the present invention is excellent in antireflection, scratch resistance and durability, and has a high contrast with a uniform display in a wide range of observation angles, so it is suitable as a large-screen flat panel display, etc. Can be used.

  The liquid crystal display device of the present invention comprises an IPS mode liquid crystal cell, at least two optical anisotropic plates, an output side polarizer provided with an antireflection plate having a low refractive index layer on the observation side, and an incident side polarizer. At least.

<Liquid crystal cell>
In the IPS mode liquid crystal cell used in the present invention, the liquid crystal molecules in the liquid crystal cell are homogeneously aligned with respect to the surface of the liquid crystal cell substrate when no voltage is applied, and the liquid crystal molecules in the liquid crystal cell are aligned on the substrate surface when voltage is applied. Rotating parallel to the axis and twisting by 90 °. Specifically, methods described in Japanese Patent Application Laid-Open Nos. 09-080424 and 2001-100207 are known.

<Optical anisotropic plate>
Optically anisotropic plate used in the present invention, the slow axis direction of the refractive indices n _x in the plane of the optically anisotropic plate measured with light having a wavelength 550 _nm, in a direction perpendicular in the slow axis and the plane of the plane when the refractive index n _y, the refractive index in the thickness direction is n _z, n x, a plate-like material at least one is different from the other of the n _y and n _z, and the display screen of the liquid crystal display device It has the same size. In the optical anisotropic plate, when light emitted from one monochromatic light source travels in one direction, the light travels in two polarizations having different velocities, and the vibration directions of the two polarizations are perpendicular to each other.
The optical anisotropic plate used in the present invention is preferably a layer containing a material having a negative intrinsic birefringence value. Further, the optical anisotropic plate used in the present invention is preferably a layer containing discotic liquid crystal or lyotropic liquid crystal. Furthermore, the optically anisotropic plate used in the present invention is preferably a layer containing a photoisomerized substance.

(I) Layer including a material having a negative intrinsic birefringence value A material having a negative intrinsic birefringence value is a material having a negative intrinsic birefringence value. The refractive index is smaller than the refractive index of light in the direction orthogonal to the orientation direction.

  Examples of materials having a negative intrinsic birefringence value include vinyl aromatic polymer resins such as polystyrene, acrylic resins such as polyacrylonitrile and polymethyl methacrylate, polycarbonate resins such as polycarbonate, and cellulose acetate resins such as triacetyl cellulose. And multicomponent copolymers thereof. These materials having a negative intrinsic birefringence value can be used singly or in combination of two or more. Among these, vinyl aromatic polymer resins and acrylic resins can be preferably used, and vinyl aromatic polymer resins can be particularly preferably used because of their high birefringence.

  Examples of the vinyl aromatic polymer resin include polystyrene, styrene, α-methylstyrene, o-methylstyrene, p-methylstyrene, p-chlorostyrene, p-nitrostyrene, p-aminostyrene, p- Vinyl aromatic monomers such as carboxystyrene and p-phenylstyrene, ethylene, propylene, butadiene, isoprene, (meth) acrylonitrile, α-chloroacrylonitrile, methyl (meth) acrylate, ethyl (meth) acrylate, ( Examples thereof include copolymers with other monomers such as (meth) acrylic acid, maleic anhydride, and vinyl acetate. Among these, polystyrene or a copolymer of styrene and maleic anhydride can be suitably used.

    The material having a negative intrinsic birefringence value includes, as necessary, an antioxidant, a heat stabilizer, a light stabilizer, an ultraviolet absorber, an antistatic agent, a dispersant, a chlorine scavenger, a flame retardant, and a crystallization. Nucleating agent, antiblocking agent, antifogging agent, release agent, pigment, organic or inorganic filler, neutralizing agent, lubricant, decomposition agent, metal deactivator, antifouling agent, antibacterial agent and other resins, And well-known additives, such as a thermoplastic elastomer, can be added in the range which does not impair the effect of invention.

  The layer including a material having a negative intrinsic birefringence value may include a material having a positive intrinsic birefringence value. Further, it is preferably a laminate in which a layer made of a material having a positive intrinsic birefringence value is laminated on at least one surface of a layer made of a material having a negative intrinsic birefringence value, and the intrinsic birefringence value is negative. A laminate in which layers made of other materials are laminated on both sides of the material layer is particularly preferable.

  A laminate in which a layer made of a material having a negative intrinsic birefringence value and a layer made of a material having a positive intrinsic birefringence value are stacked on at least one side of a layer made of a material having a negative intrinsic birefringence value. There is no restriction | limiting in particular as a method to manufacture this, For example, conventionally well-known methods, such as a solution casting method, an injection molding method, and a melt extrusion method, are mentioned.

  The layer made of a material having a negative intrinsic birefringence value is preferably a layer in which a layer made of a material having a negative intrinsic birefringence value is oriented. Further, from the viewpoint of excellent processing performance, efficient and easy formation of an optically anisotropic plate, and a stable and homogeneous phase difference over a long period of time, a layer made of a material having a negative intrinsic birefringence value It is preferable that the laminate in which a layer made of a material having a positive intrinsic birefringence value is laminated on at least one side of the layer is an oriented layer, and an intrinsic birefringence is formed on both sides of a layer made of a material having a negative intrinsic birefringence value. It is particularly preferable that the laminate in which layers made of materials having a positive refraction value are laminated is an oriented layer. In this case, the layer made of a material having a positive intrinsic birefringence value may be substantially unoriented from the viewpoint of efficiently using the phase difference of the layer made of a material having a negative intrinsic birefringence value. preferable.

A layer made of a material having a positive intrinsic birefringence value is provided on at least one side of the layer made of a material made of a material having a negative intrinsic birefringence value and a layer made of a material having a negative intrinsic birefringence value. A method for producing a layer in which the laminated body is oriented is not particularly limited, but a material having a negative intrinsic birefringence value from the viewpoint of uniformly and efficiently controlling the refractive index in the thickness direction of the optical anisotropic body. A method of stretching a laminate in which a layer made of a material having a positive intrinsic birefringence value is laminated on at least one side of a layer made of or a layer made of a material having a negative intrinsic birefringence value is preferable.
From the viewpoint of controlling the in-plane refractive index of the optical anisotropic body, a method of further laminating another stretched film on the layer made of the material having a negative stretched intrinsic birefringence value is also preferable.
Furthermore, it is preferable that the layer made of a material having a negative intrinsic birefringence value is a laminate in which layers made of other materials are laminated on both sides via an adhesive resin layer. This makes it possible to stretch at a temperature at which birefringence easily develops even if it is a layer made of a material having a negative intrinsic birefringence value that is difficult to stretch by itself and has low strength. It is possible to obtain an optical anisotropic plate having a uniform retardation over the entire surface.

  A layered body in which a layer made of a material having a negative intrinsic birefringence value is oriented and a layered body in which a layer made of another material is laminated on at least one side of a layer made of a material having a negative intrinsic birefringence value are oriented. There is no restriction | limiting in particular in the extending | stretching method of a layer, A conventionally well-known method can be applied. Specifically, a uniaxial stretching method such as a method of uniaxially stretching in the longitudinal direction using a difference in peripheral speed between rolls, a method of uniaxially stretching in the lateral direction using a tenter; Tenter by holding both ends of the clip after stretching in the longitudinal direction using the simultaneous biaxial stretching method that stretches in the transverse direction according to the spread angle of the guide rail at the same time as stretching in the longitudinal direction or the difference in peripheral speed between the rolls. A biaxial stretching method such as a sequential biaxial stretching method in which the film is stretched in the transverse direction by using a tenter stretching machine that can add a feed force, a pulling force, or a take-up force at different speeds in the lateral or longitudinal direction; Alternatively, tenter stretching with the same moving distance and fixed stretching angle, or different moving distance, by adding a feed force or pulling force or pulling force at the same speed in the left and right direction in the longitudinal direction. How to oblique stretching using: and the like.

As described above, a layer made of a material having a negative intrinsic birefringence value is stretched, or a layer made of another material is laminated on at least one side of a layer made of a material having a negative intrinsic birefringence value. By stretching the laminate, the refractive index in the direction perpendicular to the stretching direction of these layers is increased, the refractive index in the stretching direction is decreased, and an optical difference satisfying (Σn _ix + Σn _iy ) / 2 ≦ Σn _iz described later. A square plate can be formed efficiently and preferably.

(Ii-1) Layer containing discotic liquid crystal molecules As discotic liquid crystal molecules, compounds described in various literatures (for example, C. Desradet et al., Mol. Crysr. Liq. Cryst., Vol. 71). , Page 111 (1981), the research report of B. Kohne et al., The cyclohexane derivative described in Angew. Chem. 96, 70 (1984), and J. M. Lehn. J. Chem. Commun., 1794 (1985), J. Zhang et al., And J. Am. Chem. Soc. 116, 2655 (1994). Azacrown type or phenylacetylene type, macrocycle, etc.) , The radially from disk-like structure of the central portion of the molecule is a compound having a mutually identical or different side chain portion of the plurality extending structure. In the side chain portion, for example, an alkyl group, an alkoxy group, a substituted benzoyloxy group or the like is substituted. Specific examples of such discotic liquid crystals are shown below.

  The layer containing the discotic liquid crystal molecules is formed so that the discotic liquid crystal molecules are in contact with the substrate surface from the viewpoint that the optical anisotropic plate can be formed efficiently and easily and that the phase can be stable and homogeneous over a long period of time. It is preferable to consist of substantially vertically oriented layers. The term “substantially vertical alignment” means that the discotic liquid crystal molecules are aligned at an average inclination angle in the range of 50 to 90 ° with respect to the substrate surface. Examples of the substrate include films and plates made of glass or resin. From the viewpoints of weight reduction, thickness reduction, production efficiency, etc., the layer containing discotic liquid crystal molecules is substantially perpendicular to the exit side polarizer, the entrance side polarizer and the liquid crystal cell. It may be what you did.

  The method for producing the optical anisotropic plate from the layer containing the discotic liquid crystal molecules is not particularly limited, but a method of laminating the discotic liquid crystal molecules on the substrate is preferable, and the refractive index in the thickness direction of the optical anisotropic plate is preferred. From the viewpoint of efficiently controlling the thickness, a method of laminating the discotic liquid crystal molecules so as to be substantially vertically aligned with respect to the substrate surface is particularly preferable.

  As a method for vertically aligning the discotic liquid crystal molecules, for example, is it possible to apply and fix a discotic liquid crystal molecule or a coating liquid containing a polymerizable initiator and other additives described later on the vertical alignment film? Alternatively, the coating liquid is applied on the vertical alignment film and fixed, and then the vertical alignment film is peeled off and a layer containing the remaining discotic liquid crystal molecules is laminated on the substrate.

Examples of the solvent used for preparing the coating solution include water and organic solvents. Examples of organic solvents include amides such as N, N-dimethylformamide; sulfoxides such as dimethyl sulfoxide; heterocyclic compounds such as pyridine; hydrocarbons such as benzene and hexane; alkyl halides such as chloroform and dichloromethane; methyl acetate, acetic acid Examples thereof include esters such as butyl; ketones such as acetone and methyl ethyl ketone; ethers such as tetrahydrofuran and 1,2-dimethoxyethane. Two or more organic solvents may be used in combination.
The coating liquid can be applied by a known method such as an extrusion coating method, a direct gravure coating method, a reverse gravure coating method, or a die coating method.

The vertical alignment film refers to a film having such a low surface energy that liquid crystal molecules can be aligned vertically. The vertical alignment film is usually composed of a polymer. In particular, from the viewpoint of reducing the surface energy of the alignment film, a polymer in which a fluorine atom or a hydrocarbon group having 10 or more carbon atoms is introduced into the side chain of the polymer can be suitably used. The hydrocarbon group is an aliphatic group, an aromatic group or a combination thereof. The main chain of the polymer preferably has a polyimide structure or a polyvinyl alcohol structure.
The polymerization degree of the polymer used for the vertical alignment film is preferably 200 to 5,000, and more preferably 300 to 3,000. Although there is no restriction | limiting in particular about the molecular weight of a polymer, The weight average molecular weight (Mw) of polyethylene oxide or polystyrene (standard solution) conversion measured with the gel permeation chromatograph using tetrahydrofuran as a solvent is 9,000-200,000. It is preferable that it is 13,000-130,000. Two or more kinds of polymers may be used in combination.
The vertical alignment film can be formed by applying a polymer used for the vertical alignment film to a substrate. Furthermore, it is preferable to perform a rubbing process on the vertical alignment film. The rubbing treatment is performed by rubbing the surface of the film containing the polymer several times in a certain direction with paper or cloth.

The vertically aligned discotic liquid crystal molecules are fixed while maintaining the alignment state. The immobilization method is preferably performed by a polymerization reaction. Note that the liquid crystal molecules fixed in the vertical alignment state can maintain the alignment state without the vertical alignment film.
Preferred examples of the polymerization reaction include a thermal polymerization reaction using a thermal polymerization initiator and a photopolymerization reaction using a photopolymerization initiator.
As photopolymerization initiators, α-carbonyl compounds (described in the specifications of US Pat. Nos. 2,367,661 and 2,367,670), acyloin ethers (described in US Pat. No. 2,448,828), α-hydrocarbon substituted aromatic acyloin compounds ( US Pat. No. 2,722,512), polynuclear quinone compound (described in US Pat. Nos. 3,046,127 and 2,951,758), a combination of triarylimidazole dimer and p-aminophenyl ketone (described in US Pat. No. 3,549,367) And acridine and phenazine compounds (JP-A-60-105667, described in US Pat. No. 4,239,850) and oxadiazole compounds (described in US Pat. No. 4,212,970).

As described above, by forming a layer in which the discotic liquid crystal molecules are vertically aligned, the refractive index in a direction substantially parallel to the disc surface of the discotic liquid crystal molecules vertically aligned in this layer is large, and the disc surface method The refractive index in the linear direction becomes small, and an optical anisotropic plate satisfying (Σn _ix + Σn _iy ) / 2 ≦ Σn _iz described later can be efficiently and preferably formed.

(Ii-2) Layer containing lyotropic liquid crystal molecules A lyotropic liquid crystal molecule refers to a molecule exhibiting liquid crystallinity when dissolved in a specific solvent in a specific concentration range (Maruzen Co., Ltd., Liquid Crystal Handbook). See 3p etc.). Specifically, JP-A-10-333145, Mol. Cryst. Liq. Cryst. 1993 Vol. 225, 293-310, etc., a polymer lyotropic liquid crystal molecule obtained by dissolving a polymer having a main chain of a rod-like skeleton such as a cellulose derivative, polypeptide, nucleic acid, etc .; a concentrated aqueous solution of an amphiphilic low-molecular compound An amphiphilic lyotropic liquid crystal molecule comprising: a chromonic liquid crystal molecule comprising a solution of a low molecular compound having an aromatic ring imparted with water solubility; and the like.
The lyotropic liquid crystal molecules preferably have a characteristic of being oriented in a specific direction by shearing. The lyotropic liquid crystal molecules preferably have substantially no absorption in the visible light region. Specific examples of such lyotropic liquid crystal molecules are shown below.

  The layer containing the lyotropic liquid crystal molecules has a lyotropic liquid crystal molecule with respect to the substrate surface from the viewpoint that the optical anisotropic plate can be formed efficiently and easily and can have a stable and homogeneous phase difference over a long period of time. It is preferable to consist of substantially vertically oriented layers. The term “substantially vertical alignment” means that the lyotropic liquid crystal molecules are aligned at an average inclination angle in the range of 50 to 90 ° with respect to the substrate surface. Examples of the substrate include films and plates made of glass or resin.

  The method for producing the optical anisotropic plate from the layer containing the lyotropic liquid crystal molecules is not particularly limited, but a method of laminating the lyotropic liquid crystal molecules on the substrate is preferable, and the refractive index in the thickness direction of the optical anisotropic plate is preferred. From the viewpoint of efficiently controlling the thickness, a method of laminating the lyotropic liquid crystal molecules so as to be substantially vertically aligned by shearing with respect to the substrate surface is preferable.

  Examples of the method for vertically aligning lyotropic liquid crystal molecules by shearing include a method of applying a solution of lyotropic liquid crystal molecules or a solution containing the additive and an additive described later on a substrate and fixing the solution. In this alignment treatment, an alignment film is not used because it is excellent in production efficiency, can achieve weight reduction and thinning, and can prevent damage to the base material and can be applied with a uniform thickness. Is preferred.

Examples of the solvent used for dissolving the lyotropic liquid crystal molecules include water and organic solvents. Examples of organic solvents include amides such as N, N-dimethylformamide; sulfoxides such as dimethyl sulfoxide; heterocyclic compounds such as pyridine; hydrocarbons such as benzene and hexane; alkyl halides such as chloroform and dichloromethane; methyl acetate, acetic acid Examples thereof include esters such as butyl; ketones such as acetone and methyl ethyl ketone; ethers such as tetrahydrofuran and 1,2-dimethoxyethane. Two or more organic solvents may be used in combination.
The concentration of the solution containing the lyotropic liquid crystal molecules is not particularly limited, but is preferably 0.0001 to 100 parts by weight, more preferably 0.0001 to 100 parts by weight of the liquid crystal molecules with respect to 100 parts by weight of the solvent. Dissolve in the range of 1 part by weight.

  In the solution containing the lyotropic liquid crystal molecules, if necessary, a polymerization initiator, an antioxidant, a heat stabilizer, a light stabilizer, an ultraviolet absorber, an antistatic agent, a dispersant, a chlorine scavenger, a flame retardant, Crystallization nucleating agent, antiblocking agent, antifogging agent, release agent, pigment, organic or inorganic filler, neutralizing agent, lubricant, decomposition agent, metal deactivator, antifouling material, plasticizer, adhesive Well-known additives such as antibacterial agents, other resins, and thermoplastic elastomers can be added within a range that does not impair the effects of the invention. These additives are usually added in an amount of 0 to 5 parts by weight, preferably 0 to 3 parts by weight, with respect to 100 parts by weight of the solution containing lyotropic liquid crystal molecules.

  The solution containing the lyotropic liquid crystal molecules can be applied by a known method such as an extrusion coating method, a direct gravure coating method, a reverse gravure coating method, or a die coating method.

  The lyotropic liquid crystal molecules vertically aligned by shearing are fixed while maintaining the alignment state. Examples of the immobilization method include solvent removal by drying, a polymerization reaction, a combination of these methods, and the like. Examples of the polymerization reaction include a thermal polymerization reaction using a thermal polymerization initiator and a photopolymerization reaction using a photopolymerization initiator.

As described above, by forming a layer in which lyotropic liquid crystal molecules are vertically aligned, the refractive index in a direction substantially perpendicular to the shear direction of the lyotropic liquid crystal molecules vertically aligned by shearing is increased, and The refractive index becomes small, and an optical anisotropic plate satisfying (Σn _ix + Σn _iy ) / 2 ≦ Σn _iz described later can be efficiently and preferably formed.

(Iii) Layer containing photoisomerization substance The photoisomerization substance is a substance that causes stereoisomerization or structural isomerization by light, and preferably its reverse isomerization is caused by light or heat of another wavelength. Is. In general, many of these compounds are accompanied by a change in color tone in the visible region together with a structural change, and are well known as photochromic compounds. As photoisomers, azobenzene compounds, benzaldoxime compounds, azomethine compounds, stilbene compounds, spiropyran compounds, spirooxazine compounds, fulgide compounds, diarylethene compounds, cinnamic acid compounds, retinal compounds Compounds, hemithioindigo compounds and the like.

  The photoisomerizable substance, that is, a compound having a photoisomerizable functional group (such as an azo group or an internal olefin) may be a low molecular compound or a polymer. In the case of a polymer, the photoisomerizable group is present in the main chain. Even in the side chain, the same function can be exhibited. Further, the polymer may be a homopolymer or a copolymer, and the copolymerization ratio of the copolymer is selected within a range that does not impair the properties of the present invention in order to appropriately adjust the polymer physical properties such as photoisomerization ability and Tg. . Further, the compound having these photoisomerizable groups may be a liquid crystal polymer. That is, a functional group capable of photoisomerization may be included in the molecule of the liquid crystal compound. For photoisomerization, see Polymers, 41, (12), (1992), p884, “Chromic Materials and Applications” (CMMC) p221, “Mechanochemistry” (Maruzen), p21, “Polymer Papers”. 147 vol.10 "(1991) p771 and the like. Specific examples of such photoisomerized materials are shown below.

  A layer containing a photoisomerized substance is a photoisomerized isomerized into a specific isomer from the viewpoint that an optical anisotropic plate can be formed efficiently and easily and can have a stable and homogeneous phase difference over a long period of time. A layer made of a chemical substance is preferred.

  A method for producing an optical anisotropic plate from the layer containing the photoisomerization material is not particularly limited, but a solution containing the photoisomerization material is applied onto a substrate to form a film-like material, and a drying step is performed. Then, a method of irradiating linearly polarized light is preferable, and a method of irradiating linearly polarized light from a direction perpendicular to the film surface is particularly preferable. Examples of the substrate include films and plates made of glass or resin.

  Although there is no restriction | limiting in particular in the solvent used for preparation of the solution containing a photoisomerization substance, Organic solvents, such as a methylene chloride, acetone, methanol, methyl ethyl ketone, are mentioned. The concentration of the coating solution is selected in order to obtain a viscosity suitable for coating, and is not particularly limited, but is preferably 1 to 50% by weight. As a coating method, a known coating method such as bar coating or roll coating can be used.

  In the case of irradiating with linearly polarized light, it can be performed from the time when the coating layer is almost dried. In general, the term “dry” refers to a residual solvent in the coating layer of 10% by weight or less. The optimum temperature for polarized light irradiation varies depending on the amount of residual solvent, but is particularly preferably in the range of Tg-50 ° C to Tg + 30 ° C. A polarized light source is not particularly limited, and a mercury lamp, a halogen lamp, or the like is preferably used.

As described above, by irradiating the layer containing the photoisomerizable material with linearly polarized light, the refractive index in the direction substantially perpendicular to the polarization axis of the irradiated light is large, and the refractive index in the direction of the polarization axis of the irradiated light is small. Thus, an optical anisotropic plate satisfying (Σn _ix + Σn _iy ) / 2 ≦ Σn _iz described later can be efficiently and preferably formed.

In the optical anisotropic plate used in the present invention, the number of the optical anisotropic plate is i, and the main refractive index in the plane of the i-th optical anisotropic plate is n _ix , n _iy (where n _ix > n _ii ). ), When the main refractive index in the thickness direction is n _iz , (Σn _ix + Σn _iy ) / 2 ≦ Σn _iz is satisfied. When (Σn _ix + Σn _iy ) / 2> Σn _iz , when the display screen of the liquid crystal display device is viewed from an oblique direction, the black display quality is poor and the contrast is lowered. In the present invention, the contrast (CR) is expressed by CR = Y _ON / Y _OFF when the brightness at the time of dark display of the liquid crystal display device is Y _OFF and the brightness at the time of bright display is Y _ON. Say. The greater the contrast, the better the visibility. Here, the bright display means a state where the brightness of the liquid crystal display is the brightest, and the dark display means a state where the brightness of the liquid crystal display is the darkest.

At least one optically anisotropic plate used in the present _invention, n z> _{n y,} and is preferably the absolute value of the difference between _{n x} and _{n z} is 0.003 or _less, n z -n _y is 0.00001 or more and more preferably an absolute value of the difference between _{n x} and nz is 0.001 or _less, n z -n _y is 0.00003 or more, and the difference between _{n x} and _{n z} The absolute value of is more preferably 0.0008 or less. Wherein when n _z and said n _y satisfy the above relationship, the contrast of the liquid crystal display device of the present invention is improved.

At least one optically anisotropic plate used in the present invention, the _{n x,} n y, wherein using _{n z: (n x -n z} ) / (n x -n y) value represented by NZ ( NZ value) is preferably 0.9 or less, more preferably 0.4 or less, still more preferably 0.2 or less, particularly preferably 0 or less, and most preferably -0.2 or less. When the NZ value is in the above range, R ₄₀ / R ₀ described later can be efficiently brought close to 1, and the contrast of the liquid crystal display device of the present invention can be increased.

<Optical laminated plate (O) formed by laminating an optical anisotropic plate and a liquid crystal cell>
In the optical laminated plate (O) formed by laminating the optical anisotropic plate and the liquid crystal cell, the retardation when light having a wavelength of 550 nm is perpendicularly incident is R ₀ , and the light having a wavelength of 550 nm is from the normal to the main axis direction. When the retardation when incident at an angle of 40 degrees is R ₄₀ ,
0.90 <R ₄₀ / R ₀ <1.10
And more preferably
0.92 <R ₄₀ / R ₀ <1.08
And more preferably
_{0.95 <R 40 / R 0 <} 1.05
It is. When R ₄₀ / R ₀ is in the above range, the black display quality is improved and the contrast is improved when the display screen is viewed from an oblique direction. The retardation R ₄₀ when light having a wavelength of 550 nm is incident at an angle of 40 degrees from the normal to the principal axis is a polar angle with the slow axis of the optical laminate (O) shown in FIG. Then, the α direction in which the light ray exists in the YZ plane and the polar angle with the fast axis of the optical laminated plate (O) as the rotation axis, the two directions in the β direction in which the light ray exists in the XZ plane. Measure about. The polar angle is an angle when viewing from the front direction when observing the display screen of the liquid crystal display device.

<Emission side polarizer and incident side polarizer>
The exit side polarizer and the entrance side polarizer used in the present invention can convert natural light into linearly polarized light. For example, a polarizer obtained by subjecting a film made of a vinyl alcohol polymer such as polyvinyl alcohol or partially formalized polyvinyl alcohol to dyeing, stretching or crosslinking with a dichroic substance such as iodine or a dichroic dye. Can be mentioned. The thicknesses of the exit-side polarizer and the entrance-side polarizer are not particularly limited, but usually a polarizer having a thickness of 5 to 80 μm is preferable. The exit-side polarizer is a polarizer provided closer to the viewing side of the liquid crystal display device of the present invention, and the incident-side polarizer is on the viewing side of the liquid crystal display device of the present invention. It is a polarizer provided in the far side. The observation side of the liquid crystal display device is the side on which the observer can visually recognize the display screen.

  The exit side polarizer and the entrance side polarizer usually have protective films laminated on both sides thereof. As the protective film, a film made of a polymer resin excellent in transparency, mechanical strength, thermal stability, moisture shielding properties and the like can be suitably used. Examples of such polymer resins include polymer resins having an alicyclic structure, cellulose polymer resins such as cellulose diacetate, cellulose triacetate, and cellulose acetate butyrate; polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, and the like. The polyester polymer resin may be used. Polymer resin and polyester polymer resin having an alicyclic structure have good transparency, lightness, dimensional stability, and film thickness controllability, and cellulosic polymer resin has good transparency and lightness. Therefore, it can be suitably used.

  Examples of the polymer resin having an alicyclic structure include a norbornene polymer, a monocyclic olefin polymer, and a vinyl alicyclic hydrocarbon polymer. Among these, norbornene-based polymers can be suitably used because they have good transparency and moldability. Examples of the norbornene-based polymer include a ring-opening polymer of a norbornene-based monomer, a ring-opening copolymer of a norbornene-based monomer and another monomer, and a hydrogenated product of these polymers; Examples include addition polymers of monomers, addition copolymers of norbornene monomers and other monomers, and hydrogenated products of these polymers. Among these, a hydrogenated product of a ring-opening polymer or a ring-opening copolymer of a norbornene monomer is particularly preferable because it is excellent in transparency.

  The optical anisotropic plate is preferably used as a protective film for the exit-side polarizer or the entrance-side polarizer. By laminating the optical anisotropic plate on the liquid crystal cell side of the exit side polarizer or the entrance side polarizer, a normal protective film can be omitted, which contributes to thinning of the liquid crystal display device.

As a means for laminating the output side polarizer or the incident side polarizer and the protective film or the optical anisotropic plate, there is usually a method of bonding via an adhesive or a pressure sensitive adhesive. Examples of the adhesive or pressure-sensitive adhesive include acrylic, silicone-based, polyester-based, polyurethane-based, polyether-based, and rubber-based adhesives or pressure-sensitive adhesives. Among these, acrylic adhesives or pressure-sensitive adhesives can be suitably used because of their good heat resistance and transparency.
When bonding, the exit-side polarizer or the entrance-side polarizer, and the protective film or the optical anisotropic plate can be cut out to a desired size and bonded to each other. Or it is preferable to adhere | attach an incident side polarizer, a elongate protective film, or an optical anisotropic plate with a roll-to-roll.

<Antireflection plate>
The liquid crystal display device of the present invention includes an antireflection plate on the observation side of the exit side polarizer. This antireflection plate has a low refractive index layer to be described later. The antireflection plate may have a high refractive index layer between the exit side polarizer and the low refractive index layer.

  In the antireflection plate, the maximum reflectance of light with an incident angle of 5 degrees and a wavelength of 430 nm to 700 nm from the viewing side is usually 1.4% or less, preferably 1.3% or less. The reflectance at a wavelength of 550 nm at an incident angle of 5 degrees is usually 0.7% or less, preferably 0.6% or less. Moreover, the maximum value of the reflectance at a wavelength of 430 nm to 700 nm at an incident angle of 20 degrees is usually 1.5% or less, preferably 1.4% or less. The reflectance at an incident angle of 20 degrees and a wavelength of 550 nm is usually 0.9% or less, preferably 0.8% or less. When each reflectance is in the above range, a liquid crystal display device having excellent visibility without reflection of external light and glare can be obtained. The reflectance can be measured using a spectrophotometer (for example, an ultraviolet-visible near-infrared spectrophotometer V-550, manufactured by JASCO Corporation).

The antireflection plate has a reflectance fluctuation of usually 20% or less, preferably 10% or less, before and after the steel wool test. If the variation in reflectance exceeds 20%, the screen may be blurred or glaring. The steel wool test is a test in which the surface of the low refractive index layer is rubbed back and forth 10 times in a state where a load of 0.025 MPa is applied to steel wool # 0000. The reflectance is measured five times at five arbitrary locations in the plane, and is calculated from the arithmetic average value of these measured values. The change in reflectance before and after the steel wool test was determined by the following formula (I). Rb represents the reflectance before the steel wool test, and Ra represents the reflectance after the steel wool test.
ΔR = (Rb−Ra) / Rb × 100 (%) (I)

Similarly, the antireflection plate has a variation in the total light transmittance before and after the steel wool test, usually within 10%, preferably within 8%, more preferably within 6%. The total light transmittance is measured five times at five locations in the plane, and is calculated from the arithmetic average value of these measured values. The fluctuation of the total light transmittance before and after the steel wool test was determined by the following formula (II). Rc represents the total light transmittance before the steel wool test, and Rd represents the total light transmittance after the steel wool test.
ΔR = (Rc−Rd) / Rc × 100 (%) (II)

In the antireflection plate, the surface resistance on the low refractive index layer side described later is preferably 1.0 × 10 ¹⁰ Ω / □ or less, more preferably 5.0 × 10 ⁹ Ω / □ or less. When the surface resistance is in such a range, dust or the like hardly adheres to the surface of the antireflection plate.

≪High refractive index layer≫
In the reflector used in the present invention, the high refractive index layer may be provided between the exit side polarizer and a low refractive index layer described later, if necessary. The high refractive index layer in the present invention is a layer having a higher refractive index than a low refractive index layer described later.
The refractive index n _{H of the} high refractive index layer is preferably 1.55 or more, and more preferably 1.60 or more. When the refractive index of the high refractive index layer is 1.55 or more, there is an advantage that the antireflection performance and scratch resistance in a wide band are improved and the design of the low refractive index layer laminated on the high refractive index layer becomes easy. is there. The refractive index can be determined using a known spectroscopic ellipsometer or the like.

  The high refractive index layer is a layer having a high surface hardness. Specifically, the high refractive index layer is a layer having a hardness of “HB” or higher in a pencil hardness test defined in JIS K5600-5-4. Although the average thickness of a high refractive index layer is not specifically limited, Usually, 0.5-30 micrometers, Preferably it is 3-15 micrometers.

  The material for forming the high refractive index layer should be selected and used so that the refractive index and surface hardness of the high refractive index layer are in the above-mentioned range. A material having a high refractive index is preferably used, and a hard material is used. It is preferable. Examples thereof include organic materials such as silicone-based, melamine-based, epoxy-based, acrylic-based and urethane acrylate-based materials; inorganic materials such as silicon dioxide; Among these, urethane acrylate-based and polyfunctional acrylate-based materials can be preferably used because of their high adhesive strength and excellent productivity.

  The high refractive index layer may further contain inorganic oxide particles. By adding inorganic oxide particles to the high refractive index layer, it is possible to easily form a high refractive index layer having excellent surface scratch resistance and a refractive index of 1.55 or more. As the inorganic oxide particles used in the high refractive index layer, those having a high refractive index are preferable, and specifically, those having a refractive index of 1.6 or more, particularly 1.6 to 2.3 are preferable. Examples of such inorganic oxide particles include titania (titanium oxide), zirconia (zirconium oxide), zinc oxide, tin oxide, cerium oxide, antimony pentoxide, antimony-doped tin oxide (ATO), and phosphorus dope. Tin oxide (PTO), fluorine-doped tin oxide (FTO), tin-doped indium oxide (ITO), zinc-doped indium oxide (IZO), aluminum-doped zinc oxide (AZO), etc. be able to. Among these, antimony pentoxide is suitable as a component for adjusting the refractive index because it has a high refractive index and an excellent balance between conductivity and transparency. The primary particle diameter of the inorganic oxide particles is preferably 1 nm to 100 nm, more preferably 1 nm to 30 nm.

  The method for forming the high refractive index layer is not particularly limited. For example, the high refractive index layer can be obtained by applying the material for forming the high refractive index layer, drying, and curing the material. Examples of the substrate include the exit side polarizer and a film made of a resin. Before applying the material, the surface of the substrate may be subjected to plasma treatment, primer treatment, or the like to increase the peel strength of the high refractive index layer. As a curing method, a thermal curing method and an ultraviolet curing method can be used. Moreover, the resin for forming the substrate and the material for the high refractive index layer can be co-extruded to form a co-extruded film in which the resin for forming the substrate and the material are laminated. The surface of the high refractive index layer is preferably provided with an antiglare function. For example, the function can be realized by forming a convex shape on the surface.

≪Low refractive index layer≫
In the reflector used in the present invention, the low refractive index layer used in the present invention is a layer provided on the upper side (observation side) of the output side polarizer, or when the high refractive index layer is provided, It is a layer provided on the upper side of this high refractive index layer. The average thickness of the low refractive index layer is preferably 10 to 1000 nm, and more preferably 30 to 500 nm.

The low refractive index layer is a layer having a refractive index n _L of 1.45 or less, preferably n _L of 1.40 or less, and more preferably n _L of 1.35 to 1.40. . Moreover, it is preferable that the refractive index difference with the said output side polarizer or the said high refractive index layer which adjoins is 0.05-0.4. By providing such a low refractive index layer, it is possible to obtain a liquid crystal display device that is excellent in balance between visibility, scratch resistance, and strength and excellent in balance between antireflection performance and scratch resistance. Further, n _H ≧ 1.53 and (√n _H ) −0.2 <between the refractive index n _H of the high refractive index layer and the refractive index n _L of the low refractive index layer laminated thereon. It is preferable to have a relationship of n _L <(√n _H ) +0.2 in order to develop the antireflection function.

  In the antireflection plate used in the present invention, the low refractive index layer comprises a hollow particle (A) having a particle size of 5 to 2000 nm, a siloxane oligomer (B) having a (meth) acryloyl group and a fluoroalkyl group, and (meta ) A cured film of a composition containing an acrylate compound (C) having an acryloyl group. In the present invention, (meth) acryloyl means acryloyl and methacryloyl.

[Hollow particles (A)]
The hollow particles used in the present invention are particles having a hollow portion.
Further, the solvent used when preparing the hollow particles and / or the gas that enters during the drying may be present in the hollow part of the hollow particles, or a precursor described later for forming the hollow part of the hollow particles. The substance may remain in the hollow part.
The precursor material is a porous material that remains after removing some of the constituent components of the core particles from the core particles surrounded by the outer shell. As the core particles, porous composite oxide particles made of different types of inorganic oxides are used. The precursor material may remain slightly attached to the outer shell, or it may occupy most of the hollow portion of the hollow particles.
The solvent or gas may be present in the pores of the porous material. If the removal amount of the constituent components of the core particles at this time increases, the volume of the hollow part of the hollow particles increases, and hollow particles having a low refractive index are obtained. The transparent film obtained by blending these hollow particles has a low refractive index. Excellent antireflection performance at a high rate.

  The hollow particles (A) contained in the low refractive index layer used in the present invention have a particle size in the range of 5 to 2,000 nm, and preferably in the range of 20 to 100 nm. When the particle size of the hollow particles (A) is below the above range, the refractive index of the low refractive index layer is not sufficiently small, and when the particle size of the hollow particles (A) is within the above range, antireflection is performed. The transparency of the plate can be maintained, and the contribution due to diffuse reflection can be reduced. The particle diameter of the hollow particles here is a number average particle diameter by observation with a transmission electron microscope.

The outer shell of the hollow particle (A) may be porous having pores, or may be one in which the pores are closed and the cavity is sealed against the outside of the outer shell.
The outer shell preferably has a multilayer structure including an inner layer and an outer layer. The outer shell is preferably a plurality of inorganic oxide film layers including an inner first inorganic oxide film layer and an outer second inorganic oxide film layer. By providing the second inorganic oxide coating layer on the outer side, the outer shell can be densified by closing the pores of the outer shell, and hollow particles in which the inner cavity is sealed can be obtained.

  The thickness of the outer shell of the hollow particles (A) is usually 1 to 50 nm, preferably 5 to 20 nm. The thickness of the outer shell of the hollow particles (A) is preferably in the range of 1/50 to 1/5 of the average particle diameter of the hollow particles.

  When the first inorganic oxide coating layer and the second inorganic oxide coating layer are provided as outer shells as described above, the total thickness of these layers may be in the range of 1 to 50 nm. For the densified outer shell, the thickness of the second inorganic oxide coating layer is preferably in the range of 20 to 40 nm.

  Composition comprising the hollow particles (A), the siloxane oligomer (B) having the (meth) acryloyl group and the fluoroalkyl group, and the acrylate compound (C) having the (meth) acryloyl group (coating liquid described later) The content of the hollow particles is not particularly limited, but is preferably 10 to 30% by weight. Within this range, both low refractive index properties and scratch resistance can be achieved.

The hollow particles (A) are preferably inorganic hollow particles, particularly silica-based hollow particles. The inorganic compound constituting the inorganic hollow _{particles, SiO 2, Al 2 O 3} , B 2 O 3, TiO 2, ZrO 2, SnO 2, Ce 2 O 3, P 2 O 5, Sb 2 O 3, MoO 3 _{, ZnO 2, WO 3, TiO} 2 -Al 2 O 3, TiO 2 -ZrO 2, In 2 O 3 -SnO 2, Sb 2 O 3 -SnO 2 or the like can be exemplified. These can be used alone or in combination of two or more.

  The hollow particles can be produced, for example, based on the method described in JP-A-2001-233611. Commercially available hollow particles may also be used. Moreover, in order to improve the bonding property with the siloxane oligomer (B) and the acrylate compound (C) described later, the hollow particles are obtained by reacting the hollow particles with a surfactant or a coupling agent. Hydrophilic groups such as hydroxyl groups and acryloyl groups may be introduced on the surface. As the surfactant or coupling agent, 3,3,3-trifluoropropyltrimethoxysilane, methyl-3,3,3-trifluoropropyldimethoxysilane, heptadecafluorodecylmethyldimethoxysilane, heptadecafluorodecyl Examples thereof include fluorine-containing organosilicon compounds such as trichlorosilane, heptadecafluorodecyltrimethoxysilane, and tridecafluorooctyltrimethoxysilane.

[Siloxane oligomer (B)]
The siloxane oligomer (B) contained in the low refractive index layer used in the present invention is a siloxane oligomer having a (meth) acryloyl group and a fluoroalkyl group. This siloxane oligomer (B) includes a compound (b-1) having a (meth) acryloyl group, a fluorine compound (b-2) having a fluoroalkyl group, a general formula X _j SiY _4-j (wherein X Represents a monovalent hydrocarbon group which may have a substituent, j represents an integer of 0 to 2, and when j is 2, X may be the same or different. Represents a hydrolyzable group, and Y may be the same or different, and is preferably a condensate with a silane compound (b-3) having a hydrolyzable group.

(B-1) Compound having (meth) acryloyl group As the compound (b-1) having (meth) acryloyl group, methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, hydroxyethyl Examples include (meth) acrylate, glycidyl methacrylate, allyl (meth) acrylate, alkyl (meth) acrylates such as 2-ethylhexyl methacrylate, and organosilanes having a (meth) acryloyl group.
Examples of the organosilane having the (meth) acryloyl group include 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, and 3-methacryloxypropylmethyldiethoxysilane. 3-acryloxypropyltrimethoxysilane, 3-acryloxypropyltriethoxysilane, 3-acryloxypropylmethyldimethoxysilane, 3-acryloxypropylmethyldiethoxysilane, 3-methacryloxymethyltrimethoxysilane, 3-methacrylic Loxymethyltriethoxysilane, 3-methacryloxymethylmethyldimethoxysilane, 3-methacryloxymethylmethyldiethoxysilane, 3-acryloxymethyltrimethoxysilane, 3- Examples include acryloxymethyltriethoxysilane, 3-acryloxymethylmethyldimethoxysilane, 3-acryloxymethylmethyldiethoxysilane, and the like. Among these, 3-methacryloxy is considered due to handling properties, crosslinking density, reactivity, and the like. Propyltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-acryloxypropyltrimethoxysilane, and 3-acryloxypropylmethyldimethoxysilane are preferred.

(B-2) Fluorine compound having a fluoroalkyl group As the fluorine compound (b-2) having a fluoroalkyl group, a condensate of a silane compound having a fluoroalkyl group or a monomer having a fluoroalkyl group A copolymer of this and a copolymerizable monomer may be mentioned.

  As the condensate of the silane compound having a fluoroalkyl group, perfluoroalkylalkoxysilane is preferably used from the viewpoint that a siloxane oligomer can be easily formed by a sol-gel reaction.

Examples of the perfluoroalkylalkoxysilane include, for example, the general formula (2): CF ₃ (CF ₂ ) _n CH ₂ CH ₂ Si (OR ′) ₃ (wherein R ′ is an alkyl having 1 to 5 carbon atoms. And n represents an integer of 0 to 12). Specifically, for example, trifluoropropyltrimethoxysilane, trifluoropropyltriethoxysilane, tridecafluorooctyltrimethoxysilane, tridecafluorooctyltriethoxysilane, heptadecafluorodecyltrimethoxysilane, heptadecafluorodecyltri Examples thereof include ethoxysilane. Among these, the compound wherein n is 2 to 6 is preferable. These can be used alone or in combination of two or more.

  Examples of the monomer having a fluoroalkyl group include fluoroolefins such as tetrafluoroethylene, hexafluoropropylene and 3,3,3-trifluoropropylene; perfluoro (methyl vinyl ether), perfluoro (ethyl vinyl ether), perfluoro (propyl). Examples include perfluoro (alkyl vinyl ethers) such as vinyl ether), perfluoro (butyl vinyl ether), and perfluoro (isobutyl vinyl ether); perfluoro (alkoxyalkyl vinyl ether) such as perfluoro (propoxypropyl vinyl ether); and the like. These can be used alone or in combination of two or more.

  Examples of the monomer copolymerizable with the monomer having a fluoroalkyl group include vinyl ether compounds such as methyl vinyl ether, ethyl vinyl ether and allyl vinyl ether, vinyl ester compounds such as vinyl acetate and vinyl butyrate, methyl (meth) acrylate, (Meth) acrylate compounds such as ethyl (meth) acrylate, hydroxyethyl (meth) acrylate, styrene compounds such as styrene and p-hydroxymethylstyrene, unsaturated carboxylic acid compounds such as crotonic acid, maleic acid and itaconic acid, and These derivatives can be mentioned.

(B-3) formula _X j _SiY silane compound the having a hydrolyzable group represented by _4-j, a silane compound having a hydrolyzable group represented by the general formula _{X j SiY 4-j} (b- In 3), X represents a monovalent hydrocarbon group which may have a substituent. Examples of the monovalent hydrocarbon group which may have a substituent include alkyl groups such as methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group and octyl group; cyclopentyl group and cyclohexyl group A cycloalkyl group such as a phenyl group, a 4-methylphenyl group, a 1-naphthyl group, a 2-naphthyl group, an aryl group which may have a substituent, an alkenyl group such as a vinyl group or an allyl group, a benzyl group, Aralkyl groups such as phenethyl group and 3-phenylpropyl group; haloalkyl groups such as chloromethyl group, γ-chloropropyl group and 3,3,3-trifluoropropyl group; alkenylcarbonyloxyalkyl such as γ-methacryloxypropyl group Group: alkyl group having an epoxy group such as γ-glycidoxypropyl group or 3,4-epoxycyclohexylethyl group Alkyl group having an amino group such as 3-aminopropyl group; an alkyl group having a mercapto group such as γ- mercaptopropyl group include a perfluoroalkyl group such as trifluoromethyl group. Among these, an alkyl group having 1 to 4 carbon atoms, a phenyl group, and a perfluoroalkyl group are preferable from the viewpoint of easy synthesis and availability.

Y represents a hydrolyzable group. The hydrolyzable group is a group that is hydrolyzed in the presence of an acid or a base catalyst as desired to give a — (O—Si) —O— bond. Specific examples of the hydrolyzable group include alkoxyl groups such as methoxy group, ethoxy group and propoxy group; acyloxy groups such as acetoxy group and propionyloxy group; oxime group (—O—N═C—R ¹ (R ² ) ), Enoxy group (—O—C (R ¹ ) = C (R ² ) R ³ ), amino group, aminoxy group (—O—N (R ¹ ) R ² ), amide group (—N (R ¹ )) -C (= O) -R ^2), and the like. In these groups, R ¹ , R ² and R ³ each independently represent a hydrogen atom or a monovalent hydrocarbon group. Among these, as Y, an alkoxyl group is preferable from the viewpoint of availability.

The general formula _{X j SiY 4-j} with a silane compound expressed (b-3), a silicon compound wherein k is an integer of 0 to 2 is preferred. Specific examples thereof include alkoxysilanes, acetoxysilanes, oxime silanes, enoxysilanes, aminosilanes, aminoxysilanes, amidosilanes and the like. Among these, alkoxysilanes are more preferable from the viewpoint of availability.

  Examples of the tetraalkoxysilane in which j is 0 include tetramethoxysilane and tetraethoxysilane. Examples of the organotrialkoxysilane in which j is 1 include methyltrimethoxysilane, methyltriethoxysilane, and methyltriisosilane. Examples include propoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, 3,3,3-trifluoropropyltrimethoxysilane and the like. Examples of the diorganodialkoxysilane in which j is 2 include dimethyldimethoxysilane, dimethyldiethoxysilane, diphenyldimethoxysilane, diphenyldiethoxysilane, and methylphenyldimethoxysilane.

  Although the compounding quantity of a siloxane oligomer (B) is not specifically limited, It is preferable that it is 3-90 weight% with respect to the said composition (coating liquid mentioned later), and it is preferable that it is 5-80 weight%. 10 to 60% by weight is preferable. When it is within the above range, the refractive index of the low refractive index layer becomes an appropriate value, a sufficient antireflection effect is obtained, and the scratch resistance of the low refractive index layer is good.

  Although there is no restriction | limiting in particular about the molecular weight of a siloxane oligomer (B), The number average molecular weight (Mn) of polystyrene (standard solution) conversion measured with the gel permeation chromatograph using a cyclohexane as a solvent must be 5000 or more. preferable.

As a method for obtaining the siloxane oligomer (B), the compound (b-1) having the (meth) acryloyl group, the fluorine compound (b-2) having the fluoroalkyl group, and the silane compound (b-3). Can be obtained by condensation.
In the condensation, the ratio of each reaction component is not particularly limited, but the molar ratio of the compound (b-1) / the compound (b-2) / the compound (b-3) is 5 to 70/30 to 70. It is preferable to mix and condense so that it may become / 1-50 mol%, It is still more preferable to mix | blend and condense so that it may become 5-70 / 30-70 / 1-50 mol%. Furthermore, in the condensation, each reaction component is preferably heated in an alcohol solvent (eg, methanol, ethanol, etc.) in the presence of an organic acid (eg, oxalic acid, etc.).

[Acrylate compound (C)]
The acrylate compound (C) contained in the low refractive index layer used in the present invention has a (meth) acryloyl group.
From the viewpoint of effectively increasing the hardness of the antireflection plate, the acrylate compound (C) preferably does not contain a fluorine atom and has two or more (meth) acryloyl groups. Such compounds include neopentyl glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, trimethylolethane tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, Dipentaerythritol tetra (meth) acrylate, alkyl-modified dipentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, alkyl-modified dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, caprolactone Examples include modified dipentaerythritol hexa (meth) acrylate and ditrimethylolpropane tetra (meth) acrylate. Kill. These can be used alone or in combination of two or more.

  The acrylate compound (C) may contain a fluorine atom from the viewpoint of effectively reducing the refractive index of the low refractive index layer. Examples of acrylate compounds containing fluorine atoms include 2,2,2-trifluoroethyl (meth) acrylate, 2,2,3,3,3-pentafluoropropyl (meth) acrylate, and 2- (perfluorobutyl) ethyl. (Meth) acrylate, 3-perfluorobutyl-2-hydroxypropyl (meth) acrylate, 2- (perfluorohexyl) ethyl (meth) acrylate, 3-perfluorohexyl-2-hydroxypropyl (meth) acrylate, 2- (Perfluorooctyl) ethyl (meth) acrylate, 3-perfluorooctyl-2-hydroxypropyl (meth) acrylate, 2- (perfluorodecyl) ethyl (meth) acrylate, 2- (perfluoro-3-methylbutyl) ethyl (Meth) acrylate, 3- (par Fluoro-3-methylbutyl) -2-hydroxypropyl (meth) acrylate, 2- (perfluoro-5-methylhexyl) ethyl (meth) acrylate, 3- (perfluoro-5-methylhexyl) -2-hydroxypropyl ( (Meth) acrylate, 2- (perfluoro-7-methyloctyl) ethyl (meth) acrylate, 2- (perfluoro-7-methyloctyl) -2-hydroxypropyl (meth) acrylate, 1H, 1H, 3H-tetrafluoro Propyl (meth) acrylate, 1H, 1H, 5H-octafluoropentyl (meth) acrylate, 1H, 1H, 7H-dodecafluoroheptyl (meth) acrylate, 1H, 1H, 9H-hexadecafluorononyl (meth) acrylate, 1H -1- (trifluoromethyl) Lifluoroethyl (meth) acrylate, 1H, 1H, 3H-hexafluorobutyl (meth) acrylate, 2,2,3,3,4,4,5,5,6,6,7,7,8,8, Mention may be made of 9,9-hexadecafluoro-1,10-decandiol-diepoxy (meth) acrylate. These can be used alone or in combination of two or more.

  Although the compounding quantity of an acrylate compound (C) is not specifically limited, It is preferable that it is 5-90 weight% with respect to the said composition (coating liquid mentioned later), and it is preferable that it is 10-80 weight%. It is preferably 15 to 60% by weight. When it is within the above range, the refractive index of the low refractive index layer becomes an appropriate value, a sufficient antireflection effect is obtained, and the scratch resistance of the low refractive index layer is good.

  The low refractive index layer used in the present invention is a coating liquid (composition) containing the hollow particles (A), the siloxane oligomer (B), and the acrylate compound (C). It can be obtained by coating in the form of a film on another layer such as a refractive index layer, drying, and curing by ionizing radiation and / or heating.

  The said coating liquid mixes the said (A), (B), and (C) with the organic solvent which does not decompose | disassemble a hollow particle (A), a siloxane oligomer (B), and an acrylate compound (C). To be prepared. Examples of such organic solvents include alcohols such as isopropyl alcohol, methanol, and ethanol; ketones such as methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; esters such as ethyl acetate and butyl acetate; halogenated hydrocarbons; toluene, xylene, and the like Or aromatic hydrocarbons thereof; or mixtures thereof. The mixing ratio of the organic solvent and the (A), (B), and (C) is not particularly limited, but in the coating solution, the (A), (B), and (C) It is preferable to mix so that the total concentration is 0.1 to 20% by weight, preferably 0.5 to 10% by weight.

  The coating liquid contains a polymerization initiator (photo radical initiator or thermal radical initiator), a curing agent, a crosslinking agent, an ultraviolet blocker, an ultraviolet absorber, a surface conditioner (leveling agent), or other components. It may be included.

The coating method of the coating liquid is not particularly limited. Examples of the curing method include heating and actinic ray irradiation. Drying conditions and curing conditions can be appropriately determined according to the type of solvent used, such as boiling point and saturated vapor pressure. In particular, in order to suppress the other layers to be coated from being colored or decomposed, it is preferable to heat at a temperature within the range of 50 to 150 ° C. for 1 to 180 minutes. It is more preferable to heat at a temperature in the range of 75 to 105 ° C. for 5 to 60 minutes, and when irradiating actinic rays, it is preferable to use ultraviolet rays as the irradiation light. The irradiation energy is preferably from 50 to 500 mJ / cm ^2, more preferably 100~450mJ / cm ^2, further preferably 200 to 400 mJ / cm ^2.

≪Anti-fouling layer≫
In the antireflection plate used in the present invention, an antifouling layer may be further formed on the low refractive index layer (observation side) in order to enhance the antifouling property of the low refractive index layer. The material for forming the antifouling layer is not particularly limited as long as the function of the low refractive index layer is not impaired and the required performance as the antifouling layer is satisfied. Usually, a compound having a hydrophobic group can be preferably used. As specific examples, a perfluoroalkylsilane compound, a perfluoropolyethersilane compound, or a fluorine-containing silicone compound can be used. As the method for forming the antifouling layer, for example, a physical vapor deposition method such as vapor deposition or sputtering; a chemical vapor deposition method such as CVD; a wet coating method; The thickness of the antifouling layer is not particularly limited, but is usually preferably 20 nm or less, and more preferably 1 to 10 nm.

<Arrangement configuration of liquid crystal display device>
Here, an outline of the configuration of the liquid crystal display device of the present invention will be described.
2, FIG. 3, FIG. 4 and FIG. 5 are explanatory diagrams showing examples of the configuration of the liquid crystal display device of the present invention. The liquid crystal display device includes an incident side polarizer 1, a liquid crystal cell 2, an optical anisotropic plate 3, an optical anisotropic plate 4, and an output side polarizer 5. On the observation side of the exit-side polarizer 5, an antireflection plate having a low refractive index layer is provided. The arrows in the figure indicate an absorption axis in a polarizer and an in-plane slow axis in a liquid crystal cell and an optical anisotropic body. 6 and 7 are explanatory diagrams showing two examples of the configuration of a conventional liquid crystal display device.

The liquid crystal display device of the present invention includes at least two of the optical anisotropic plate and the liquid crystal cell between a pair of polarizers composed of the exit side polarizer and the entrance side polarizer. In particular, from the viewpoint that the contrast of the liquid crystal display device of the present invention can be effectively improved, the number of the optical anisotropic plates is preferably two.
In the present invention, there is no limitation on the arrangement of at least two optical anisotropic plates and a liquid crystal cell (arrangement configuration of the optical laminated plate (O)) between a pair of polarizers, and at least two optical anisotropic plates are provided. On the other hand, a liquid crystal cell can be arranged at an arbitrary position. For example, when two optical anisotropic plates and a liquid crystal cell are used, the optical anisotropic plate-liquid crystal cell-optical anisotropic plate, optical anisotropic plate-optical anisotropic from the incident side polarizer to the output side polarizer. Any arrangement of plate-liquid crystal cell or liquid crystal cell-optical anisotropic plate-optical anisotropic plate can be used.

In the liquid crystal display device of the present invention, it is preferable that the slow axes in the plane of the optical anisotropic plate are in a substantially parallel or substantially vertical positional relationship.
In the liquid crystal display device of the present invention, the slow axis in the plane of the optical anisotropic plate is in a substantially parallel or substantially vertical positional relationship with the slow axis in the plane of the liquid crystal of the liquid crystal cell in a state where no voltage is applied. Preferably there is.
In the liquid crystal display device of the present invention, it is preferable that the slow axis in the plane of the optical anisotropic plate and the absorption axis of the output side polarizer are in a substantially parallel or substantially vertical positional relationship. In addition, it is preferable that the slow axis in the plane of the optical anisotropic plate and the absorption axis of the incident-side polarizer are in a substantially parallel or substantially vertical positional relationship.
With the above arrangement, the contrast of the liquid crystal display device of the present invention can be effectively improved.

  In the present invention, two axes being in a substantially parallel positional relationship means that when the angle is displayed at 0 to 90 degrees, the angle formed by the two axes is 0 to 3 °. In the present invention, that the two axes are in a substantially vertical positional relationship means that the angle formed by the two axes is 87 to 90 °.

  The exit-side polarizer and the entrance-side polarizer used in the liquid crystal display device of the present invention have a positional relationship in which their absorption axes are substantially vertical. When the angle formed by the two axes of the incident side polarizer and the output side polarizer is within the above range, the black display quality of the display screen is improved.

When there are two optical anisotropic plates used in the liquid crystal display device of the present invention, it is preferable that the two optical anisotropic plates have a substantially vertical positional relationship with respect to the slow axis in each plane. With the arrangement as described above, R ₄₀ / R ₀ can be brought close to 1 efficiently, and the contrast of the liquid crystal display device of the present invention can be further effectively improved.

  The liquid crystal display device of the present invention includes the low refractive index layer on the observation side of the output side polarizer. Preferably, the high refractive index layer and the low refractive index layer are provided in this order from the exit side polarizer toward the observation side (that is, the high refractive index layer and the low refractive index layer are provided from the observation side to the observation side. For the liquid crystal cell, an arrangement of a low refractive index layer, a high refractive index layer, and an exit side polarizer may be employed). By providing the low refractive index layer on the observation side of the output side polarizer, the contrast of the liquid crystal display device of the present invention can be further effectively improved.

In the liquid crystal display device of the present invention, other films or layers may be provided at appropriate positions in addition to the exit side polarizer, the entrance side polarizer, the optical anisotropic plate, the liquid crystal cell, and the antireflection plate. For example, a prism array sheet, a lens array sheet, a light diffusion plate, a light guide plate, a diffusion sheet, a brightness enhancement film, or the like can be arranged in one layer or two or more layers. In the liquid crystal display device of the present invention, a backlight is used. As the backlight, a cold cathode tube, a mercury flat lamp, a light emitting diode, electroluminescence, or the like can be used.

Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.
In the following examples and comparative examples, an in-plane switching mode liquid crystal cell having a thickness of 2.74 μm, a positive dielectric anisotropy, a birefringence Δn = 0.09884 of a wavelength of 550 nm, and a pretilt angle of 0 degree is used. Produced.
In Examples and Comparative Examples, measurement and evaluation were performed by the following methods.
(1) Thickness After embedding the optical laminate in epoxy resin, slice it to a thickness of 0.05 μm using a microtome [Daiwa Koki Kogyo Co., Ltd., RUB-2100], and cross section using a transmission electron microscope. Observe and measure. About an optical laminated board, it measures for every layer.
(2) Main refractive index of optical anisotropic plate Using an automatic birefringence meter [Oji Scientific Instruments Co., Ltd., KOBRA-21], under conditions of temperature 20 ° C. ± 2 ° C. and humidity 60 ± 5%, wavelength 550 nm the light, measuring the refractive indices n _x in the slow axis direction in a _plane, the refractive index n _y in the slow axis direction and in-plane in a direction perpendicular in the _plane, the refractive index n _z in the thickness direction.
(3) Retardation High-speed spectroscopic ellipsometer [J. A. Using Woollam, M-2000U], R ₀ and R ₄₀ are measured under conditions of a temperature of 20 ° C. ± 2 ° C. and a humidity of 60 ± 5%.
(4) Viewing angle characteristics With the background of the screen of the liquid crystal display device set to black, white characters are displayed on the screen to display the screen from the front and diagonal directions within a polar angle of 80 degrees. Observe visually.
○: White characters can be read
×: Characters cannot be read (5) Contrast ratio The front of the display screen when the liquid crystal display device is installed in an environment of 500 lux and a rectangular wave voltage of 55 Hz (white display 6 V, black display 0 V) is applied to the liquid crystal cell The luminance in the direction is measured using a color luminance meter (manufactured by Topcon Corporation, color luminance meter BM-7). Then, the ratio of the brightness at the time of white display to the brightness at the time of black display (= brightness of white display / brightness of black display) is calculated, and this is defined as contrast (CR). The greater the contrast (CR), the better the visibility.
(6) Reflectance Using a spectrophotometer [JASCO Corporation, UV-Vis near-infrared spectrophotometer V-570], the reflectance spectrum is measured at an incident angle of 5 degrees, and the reflectance in light having a wavelength of 550 nm is obtained. .
(7) Refractive index of low refractive index layer and high refractive index layer High-speed spectroscopic ellipsometer [J. A. Woollam, M-2000U], spectrum at a wavelength range of 400 to 1000 nm when measured at 20 ° C. ± 2 ° C. and humidity 60 ± 5% at incident angles of 55, 60 and 65 degrees, respectively. Calculate from
(8) Scratch resistance In a state where steel wool # 0000 is in contact with the surface of the antireflection plate, the steel wool is reciprocated 10 times on the surface of the antireflection plate (at this time, a load of 0.025 MPa is continuously applied to the steel wool). The surface condition after the test is visually observed.
○: Scratches are not recognized
Δ: Slightly scratched
X: Scratches are recognized (9) Visibility In the state where the display screen of the liquid crystal display device is black, the display on the screen is visually observed, and the following three-stage evaluation is performed.
○: No glare or reflection
Δ: Some glare and reflections can be seen
X: Glare and reflection can be seen (10) Broadband property A liquid crystal display device is installed in an environment with a brightness of 100 lux, and the reflected color is visually observed.
○: Reflection color is black
X: Reflection color is blue (11) number average molecular weight and weight average molecular weight A gel permeation chromatograph [Tosoh Corporation, HLC8020] is used to prepare a calibration curve with a standard solution and measured as a converted value.
(12) Antifouling property When a magic ink (trade name: McKee, manufactured by ZEBRA) is attached to the surface of the antireflection plate and then wiped with a cellulose nonwoven fabric (trade name: Bencott M-3, manufactured by Asahi Kasei). Visually judge the condition.
○: Can be completely wiped off
×: Wipe marks remain

(Production Example 1) (Production of optical anisotropic plate A1)
[1] layer composed of norbornene polymer [glass transition temperature 105 ° C.], [2] layer composed of styrene-maleic anhydride copolymer [glass transition temperature 130 ° C., oligomer content 3 wt%] and modified ethylene It has a [3] layer consisting of a vinyl acetate copolymer [Vicat softening point 80 ° C.], and [1] layer (33 μm)-[3] layer (8 μm)-[2] layer (65 μm)-[3] layer An unstretched laminated film a1 having a structure of (8 μm)-[1] layer (33 μm) was obtained by coextrusion molding. The obtained unstretched laminated film a1 is horizontally uniaxially stretched by a tenter at a temperature of 135 ° C., a magnification of 1.5 times, and a stretching speed of 12% / min, and is a long optical anisotropy whose slow axis is in the film longitudinal direction. Plate A1 was obtained.
The obtained optically anisotropic plate A1 had a main refractive index n _x = 1.57024, n _y = 1.56927, n _z = 1.57048, and a thickness d = 98 μm.

(Production Example 2) (Production of optical anisotropic plate B1)
[1] layer composed of norbornene polymer [glass transition temperature 105 ° C.], [2] layer composed of styrene-maleic anhydride copolymer [glass transition temperature 130 ° C., oligomer content 3 wt%] and modified ethylene [3] layer comprising a vinyl acetate copolymer [Vicat softening point 55 ° C.], [1] layer (38 μm)-[3] layer (10 μm)-[2] layer (76 μm)-[3] layer An unstretched laminated film b1 having a configuration of (10 μm)-[1] layer (38 μm) was obtained by coextrusion molding. The obtained unstretched laminated film b1 is horizontally uniaxially stretched by a tenter at a temperature of 134 ° C., a magnification of 1.7 times, a stretching speed of 12% / min, and a long optical anisotropy in which the slow axis is in the film longitudinal direction. Plate B1 was obtained.
The obtained optical anisotropic plate B1 had a main refractive index n _x = 1.57041, n _y = 1.56878, n _z = 1.57082, and a thickness d = 101 μm.

(Production Example 3) (Production of optical anisotropic plate C1)
A modified polyvinyl alcohol having a structure represented by the chemical formula [6] was dissolved in a mixed solvent of methanol and acetone (volume ratio 50:50) to prepare a solution having a concentration of 5% by weight. This solution is applied to an optically isotropic transparent glass substrate having a length of 40 cm and a width of 30 cm using a bar coater at a thickness of about 1 μm, dried with hot air at 60 ° C. for 2 minutes, and the surface is rubbed. A vertical alignment film was formed.
On the formed vertical alignment film, 32.6% by weight of discotic liquid crystal molecules having a structure represented by the chemical formula [7], 0.7% by weight of cellulose acetate butyrate, 3.2% by weight of modified trimethylolpropane triacrylate %, A sensitizer 0.4% by weight, a photopolymerization initiator 1.1% by weight and methyl ethyl ketone 62.0% by weight, and a discotic liquid crystal molecule was homogeneously aligned. Subsequently, it superposed | polymerized by irradiating an ultraviolet-ray for 1 second with the mercury lamp with the illumination intensity of 500 W / cm < ² >, and obtained the optically anisotropic board C1. The discotic liquid crystal molecules were homogeneously aligned so as to have a slow axis in the lateral direction of the optically isotropic transparent glass substrate.
The obtained optically anisotropic plate C1 had a main refractive index n _x = 1.63353, n _y = 1.53293, n _z = 1.63353, and a thickness d = 4 μm.

(Production Example 4) (Production of optical anisotropic plate D1)
A long unstretched film having a thickness of 100 μm made of a norbornene polymer [glass transition temperature 136 ° C.] was obtained by extrusion molding.
A modified polyvinyl alcohol having a structure represented by the chemical formula [6] was dissolved in a mixed solvent of methanol and acetone (volume ratio 50:50) to prepare a solution having a concentration of 5% by weight. This solution was applied to the unstretched film at a thickness of about 1 μm, dried with hot air at 60 ° C. for 2 minutes, and the surface was rubbed to form a vertical alignment film.
On the formed vertical alignment film, discotic liquid crystal molecules having a structure represented by the chemical formula [8] 22.3% by weight, cellulose acetate butyrate 0.7% by weight, modified trimethylolpropane triacrylate 3.2% by weight %, A sensitizer 0.4% by weight, a photopolymerization initiator 1.1% by weight and methyl ethyl ketone 72.3% by weight was applied to make the discotic liquid crystal molecules homogeneously aligned. Subsequently, it superposed | polymerized by irradiating an ultraviolet-ray for 1 second with the mercury lamp with an illumination intensity of 500 W / cm < ² >, and obtained the optically anisotropic plate D1. The discotic liquid crystal molecules were homogeneously aligned so as to have a slow axis in the longitudinal direction of the optical anisotropic plate D1.
The resulting optically anisotropic plate D1 is the principal refractive index _{n x = 1.60497, n y =} 1.59006, a n z = 1.60497, and a thickness of d = 4 [mu] m.

(Production Example 5) (Production of optical anisotropic plate E1)
170 parts by weight of a styrene polymer obtained by graft copolymerization of 90 parts by weight of a styrene-acrylonitrile-α-methylstyrene (weight ratio 60:20:20) mixture with 10 parts by weight of a styrene-butadiene (weight ratio 20:80) copolymer Was dissolved in 830 parts by weight of methylene chloride. This solution was cast on a glass plate so as to have a dry film thickness of 96 μm, dried with warm air of 45 ° C. for 20 minutes, and then the obtained film was peeled off from the glass plate and attached to a frame. And then dried at 110 ° C. for 15 hours. Next, longitudinal uniaxial stretching was performed using a tensile tester (strograph) at a temperature of 115 ° C. and a stretching ratio of 1.9 times to obtain an optical anisotropic plate E1.
The obtained optical anisotropic plate E1 had a main refractive index n _x = 1.555058, n _y = 1.54884, n _z = 1.555058, and a thickness d = 70 μm.

(Production Example 6) (Preparation of composition H1 for forming a high refractive index layer)
Hexafunctional urethane acrylate oligomer (trade name: NK Oligo U-6HA, Shin-Nakamura Chemical Co., Ltd.) 30 parts, butyl acrylate 40 parts, isoboronyl methacrylate (trade name: NK Ester IB, Shin-Nakamura Chemical Co., Ltd.) 30 parts, 5 parts of styrene beads (particle size 3.5 μm) and 10 parts of 2,2-diphenylethane-1-one were mixed with a homogenizer, and a 40 wt% MIBK solution of antimony pentoxide fine particles (average particle diameter 20 nm: the hydroxyl group is a pyrochlore structure) Are bonded at a ratio of 1 to the antimony atoms appearing on the surface of the coating layer in such a ratio that the weight of the antimony pentoxide fine particles accounts for 50% by weight of the total solids of the coating liquid for forming a high refractive index layer. A composition H1 for forming a high refractive index layer was prepared.

(Production Example 7) (Adjustment of composition L1 for forming a low refractive index layer)
200 parts of ethanol was put into a four-necked reaction flask equipped with a reflux tube, and 120 parts of oxalic acid was added little by little to this ethanol with stirring to prepare an ethanol solution of oxalic acid. The solution was then heated to its reflux temperature, and 50 parts of 3-acryloxypropyltrimethoxysilane (compound (b-1)), heptadecafluorooctylethyltrimethoxysilane (compound (b -2)) A mixture of 50 parts and 10 parts of tetramethoxysilane (compound (b-3)) was added dropwise. Even after completion of the dropwise addition, heating was continued for 5 hours under reflux, followed by cooling.
Next, 20 parts of dipentaerythritol hexaacrylate (acrylate compound (C)) and 5 parts of 2-hydroxy-2-methyl-1-phenylpropan-1-one (polymerization initiator) were added dropwise with stirring and mixing. Even after completion of the dropwise addition, heating was continued for 5 hours under reflux, followed by cooling.
Next, a hollow silica isopropanol dispersion sol (manufactured by Catalyst Kasei Kogyo Co., Ltd., solid content 20% by weight, average primary particle diameter of about 35 nm, outer shell thickness of about 8 nm) (hollow particles (A)), The composition L1 for forming a low refractive index layer was prepared by adding 70% by weight on a standard basis and diluting with methanol to a solid content of 1% by weight.

(Production Example 8) (Adjustment of composition L2 for forming a low refractive index layer)
Low refractive index in the same manner as in Production Example 7 except that 20 parts of 3- (perfluorooctyl) ethyl acrylate (acrylate compound (C)), which is an acrylate compound containing fluorine, was used instead of dipentaerythritol hexaacrylate. A rate layer forming composition L2 was prepared.

(Production Example 9) (Adjustment of composition L3 for forming a low refractive index layer)
A composition for forming a low refractive index layer in the same manner as in Production Example 7, except that 60 parts of tetramethoxysilane which is a siloxane oligomer having no fluoroalkyl group is used instead of 50 parts of heptadecafluorooctylethyltrimethoxysilane. L3 was prepared.

(Production Example 10) (Adjustment of composition L4 for forming a low refractive index layer)
412 parts of methanol was added to 152 parts of tetramethoxysilane, 18 parts of water and 18 parts of 0.01N hydrochloric acid were mixed, and this was mixed well using a disper. The mixture was stirred for 2 hours in a constant temperature bath at 25 ° C., and the weight average molecular weight was adjusted to 850 to obtain a silicone resin. Next, silica methanol sol (Nissan Chemical Industries, Ltd., PMA-ST, average particle size of 10 to 20 nm), which is a non-hollow particle, is added to this silicone resin solution in a weight ratio of silica methanol sol / silicone based on solid content. The resin (condensed compound equivalent) was added so as to be 80/20, and further diluted with methanol so that the total solid content was 3%, to prepare a composition L4 for forming a low refractive index layer.

(Production Example 11) (Production of Polarizer p0)
A 85 μm-thick polyvinyl alcohol film [Kuraray Co., Ltd., Vinylon # 8500] is stretched 2.5 times and immersed in an aqueous solution containing 0.2 g / L iodine and 60 g / L potassium iodide at 30 ° C. for 240 seconds. Then, it was immersed in an aqueous solution containing 70 g / L of boric acid and 30 g / L of potassium iodide, and uniaxially stretched 6.0 times in that state and held for 5 minutes. Finally, it was dried at room temperature for 24 hours to obtain a polarizer p0 having an average thickness of 30 μm and a polarization degree of 99.5%.

(Production Example 12) (Production of polarizer protective film z1)
One side of a triacetyl cellulose (TAC) film [Konica Minolta, KC8UX2M] was coated with 25 mL / m ² of a 1.5 mol / L potassium isopropyl alcohol solution and dried at 25 ° C. for 5 seconds. did. Next, the film was washed with running water for 10 seconds, and the surface of the film was dried by blowing air at 25 ° C. In this way, only one surface of the TAC film was saponified to obtain a protective film z1.

(Production Example 13) (Production of polarizer protective film z2)
Corona discharge treatment using a high-frequency transmitter [Kasuga Electric Co., Ltd., high-frequency power supply AGI-024, output 0.8 kW] on the non-saponified surface of the protective film z1 obtained in Production Example 12. And a protective film z2 having a surface tension of 0.055 N / m was obtained.

(Production Example 14) (Production of polarizer protective film z3)
A long unstretched film having a thickness of 100 μm made of a norbornene polymer [glass transition temperature 136 ° C.] was obtained by extrusion molding. A corona discharge treatment is performed on both sides of the obtained unstretched film using a high-frequency transmitter [Kasuga Electric Co., Ltd., high-frequency power supply AGI-024, output 0.8 kW], and the surface tension is 0.072 N / m. A protective film z3 was obtained.

Example 1 (Production of Liquid Crystal Display Device 1)
[Emission-side polarizer P1]
On the surface of the protective film z2 obtained in Production Example 13 that has been subjected to corona discharge treatment, the composition H1 for forming a high refractive index layer obtained in Production Example 6 was applied using a die coater, and the protective film z2 was coated at 80 ° C. The film was dried for 5 minutes in a drying oven. Then, ultraviolet rays were irradiated (accumulated dose of 300 mJ / cm ² ) to form a high refractive index layer having a thickness of 5 μm, thereby obtaining a protective film z4. The refractive index of the high refractive index layer was 1.62.
Furthermore, on the high refractive index layer side of the protective film z4, using a wire bar coater, the low refractive index layer forming composition L1 obtained in Production Example 7 was applied, left to stand for 1 hour, and dried. The obtained film was heated at 120 ° C. for 10 minutes in an oxygen atmosphere, and a low refractive index layer having a thickness of 100 nm was laminated to obtain a protective film z5.
Further, the surface of the protective film z5 obtained and the one side of the polarizer p0 obtained in Production Example 11 face each other through a roll-to-roll method through a polyvinyl alcohol-based adhesive. Were bonded to obtain an output side polarizer P1. The pencil hardness was 2H.
[Incoming side polarizer P'1]
By a roll-to-roll method through a polyvinyl alcohol-based adhesive so that the saponified surface of the protective film z1 obtained in Production Example 12 and one side of the polarizer p0 obtained in Production Example 11 face each other. These were pasted together to obtain an incident side polarizer P′1.
[Liquid crystal display device 1]
The optical anisotropic plate B1 and the liquid crystal cell obtained in Production Example 2 and the optical anisotropic plate A1 obtained in Production Example 1 are combined with the slow axis of the optical anisotropic plate B1 and the liquid crystal cell when no voltage is applied. An optical laminated plate (O1) was produced by laminating in this order so that the axis was perpendicular and the slow axis when no voltage was applied to the liquid crystal cell and the slow axis of the optical anisotropic plate A1 were parallel.
Next, the incident side polarizer P′1 obtained in Example 1 is laminated with the absorption axis of the incident side polarizer P′1 and the slow axis of the optical anisotropic plate B1 in parallel, and the protective film z1 is laminated. It laminated | stacked with the optical laminated board (O1) so that the surface which is not touched the optical anisotropic board 1. FIG.
Further, the output side polarizer P1 obtained in Example 1 is obtained by making the absorption axis of the output side polarizer P1 parallel to the slow axis of the optical anisotropic plate A1, and lowering the refractive index of the output side polarizer P2. The liquid crystal display device 1 was manufactured by laminating with the optical laminated plate (O1) so that the surface on which no layer was laminated was in contact with the optical anisotropic plate A1. At this time, the exit side polarizer was set to be the observation side of the liquid crystal display device.
When the display characteristics of the obtained liquid crystal display device 1 were visually evaluated, the display screen was good and homogeneous both when viewed from the front and when viewed from an oblique direction within a polar angle of 80 degrees. The evaluation results are shown in Table 1.

(Example 2) (Production of liquid crystal display device 2)
[Emission-side polarizer P2]
In the same manner as in Example 1, except that the low refractive index layer forming composition L2 obtained in Production Example 8 was used instead of the low refractive index layer forming composition L1 obtained in Production Example 7, An exit side polarizer P2 was obtained.
[Liquid crystal display device 2]
Then, a liquid crystal display device 2 was produced in the same manner as in Example 1 except that the output side polarizer P2 was used instead of the output side polarizer P1 obtained in Example 1.
When the display characteristics of the obtained liquid crystal display device 2 were visually evaluated, the display screen was good and homogeneous both when viewed from the front and when viewed from an oblique direction within a polar angle of 80 degrees. The evaluation results are shown in Table 1.

(Example 3) (Production of liquid crystal display device 3)
[Emission-side polarizer P3]
One side of the protective film z3 obtained in Production Example 14 is coated with the high refractive index layer-forming composition H1 obtained in Production Example 6 using a die coater, and is then dried in an 80 ° C. drying oven. And dried for 5 minutes to obtain a film. Then, ultraviolet rays were irradiated (accumulated dose 300 mJ / cm ² ) to form a high refractive index layer having a thickness of 5 μm, thereby obtaining a protective film z6.
Next, on the high refractive index layer side of the protective film z6, the low refractive index layer forming composition L1 obtained in Production Example 7 was applied using a wire bar coater, and left to dry for 1 hour. The obtained film was heated at 120 ° C. for 10 minutes under an oxygen atmosphere to form a low refractive index layer having a thickness of 100 nm, thereby obtaining a protective film z7.
Further, the roll of the protective film z7 obtained through an acrylic adhesive so that the surface on which the low refractive index layer is not laminated and the one surface of the polarizer p0 obtained in Production Example 11 face each other. They were bonded together by a two-roll method to obtain an exit side polarizer P3. The pencil hardness was H.
[Liquid crystal display device 3]
Then, a liquid crystal display device 3 was produced in the same manner as in Example 1 except that the output side polarizer P3 was used instead of the output side polarizer P1 obtained in Example 1.
When the display characteristics of the obtained liquid crystal display device 3 were visually evaluated, the display screen was good and homogeneous both when viewed from the front and when viewed from an oblique direction within a polar angle of 80 degrees. The evaluation results are shown in Table 1.

Example 4 (Production of liquid crystal display device 4)
[Liquid crystal display device 4]
The optical anisotropic plate D1 obtained in Production Example 4, the optical anisotropic plate C1 obtained in Production Example 3, and the liquid crystal cell are divided into a slow axis of the optical anisotropic plate D1 and a slow axis of the optical anisotropic plate C1. Were laminated in this order so that the slow axis of the optically anisotropic plate C1 was perpendicular to the slow axis of the liquid crystal cell when no voltage was applied, to produce an optical laminate (O4).
Next, the incident-side polarizer P′1 obtained in Example 1 is laminated with the absorption axis of the incident-side polarizer P′1 and the slow axis of the optical anisotropic plate D1 in parallel, and the protective film z1 is laminated. It laminated | stacked with the optical laminated board (O4) so that the surface which is not touched the optically anisotropic board D1.
Furthermore, the output side polarizer P1 obtained in Example 1 is obtained by making the absorption axis of the output side polarizer P1 parallel to the slow axis of the optical anisotropic plate C1, and lowering the refractive index of the output side polarizer P1. The liquid crystal display device 4 was manufactured by laminating with the optical laminated plate (O4) so that the surface on which the layer was not laminated is in contact with the optical anisotropic plate C1. At this time, the exit side polarizer was set to be the observation side of the liquid crystal display device.
When the display characteristics of the obtained liquid crystal display device 4 were evaluated visually, the display screen was good and homogeneous both when viewed from the front and when viewed from an oblique direction within a polar angle of 80 degrees. The evaluation results are shown in Table 1.

Example 5 (Production of liquid crystal display device 5)
[Liquid crystal display device 5]
A liquid crystal display device 5 was produced in the same manner as in Example 4 except that the output side polarizer P3 obtained in Example 3 was used instead of the output side polarizer P1 obtained in Example 1.
When the display characteristics of the obtained liquid crystal display device 5 were visually evaluated, the display screen was good and homogeneous both when viewed from the front and when viewed from an oblique direction within a polar angle of 80 degrees. The evaluation results are shown in Table 1.

(Comparative Example 1) (Production of liquid crystal display device 6)
[Liquid crystal display device 6]
The optical anisotropic plate E1 and the liquid crystal cell obtained in Production Example 5 are laminated so that the slow axis of the optical anisotropic plate E1 and the slow axis when no voltage is applied to the liquid crystal cell are parallel to each other. A laminate (O6) was produced.
Next, the incident side polarizer P′1 obtained in Example 1 is parallel to the absorption axis of the incident side polarizer P′1 and the slow axis when no voltage is applied to the liquid crystal cell, and the protective film z1. Was laminated with the optical laminated plate (O6) so that the surface on which the layer was not laminated was in contact with the liquid crystal cell.
Further, the output side polarizer P1 obtained in Example 1 is obtained by making the absorption axis of the output side polarizer P1 and the slow axis of the optical anisotropic plate E1 parallel to each other, and lowering the refractive index of the output side polarizer P2. The liquid crystal display device 6 was manufactured by laminating with the optical laminated plate (O6) so that the surface on which the layer was not laminated is in contact with the optical anisotropic plate E1.
When the display characteristics of the obtained liquid crystal display device 6 were visually evaluated, the display was good when viewed from the front, but the black display quality was poor when viewed from an oblique direction with an azimuth angle of 45 degrees, and the contrast Was low. The evaluation results of the obtained liquid crystal display device 6 are shown in Table 1.

(Comparative Example 2) (Production of liquid crystal display device 7)
[Liquid crystal display device 7]
The first optical anisotropic plate E1, the liquid crystal cell, and the second optical anisotropic plate E1 obtained in Production Example 5 were applied to the slow axis of the first optical anisotropic plate E1 and no voltage applied to the liquid crystal cell. The second optically anisotropic plate E1 is laminated in this order so that the slow axis of the second optical anisotropic plate E1 is perpendicular to the slow axis when no voltage is applied to the liquid crystal cell. An optical laminate (O7) was produced.
Next, the incident side polarizer P′1 obtained in Example 1 is parallel to the absorption axis of the incident side polarizer P′1 and the slow axis when no voltage is applied to the liquid crystal cell, and the protective film z1. Was laminated with the optical laminated plate (O7) so that the surface on which the is not laminated is in contact with the second optical anisotropic plate E1.
Further, in the output side polarizer P1 obtained in Example 1, the slow axis of the first optical anisotropic plate E1 and the absorption axis of the output side polarizer P1 are parallel, and the output side polarizer P2 The liquid crystal display device 7 was manufactured by laminating the optical laminated plate (O7) so that the surface on which the low refractive index layer was not laminated is in contact with the first optical anisotropic plate E1.
When the display characteristics of the obtained liquid crystal display device 7 were evaluated visually, the display was good when viewed from the front, but the black display quality was poor when viewed from an oblique direction with an azimuth angle of 45 degrees, and the contrast Was low. The evaluation results of the obtained liquid crystal display device 7 are shown in Table 1.

(Comparative Example 3) (Production of liquid crystal display device 8)
[Output-side polarizer P8]
In the same manner as in Example 1, except that the low refractive index layer forming composition L3 obtained in Production Example 9 was used instead of the low refractive index layer forming composition L1 obtained in Production Example 7, An exit side polarizer P8 was obtained. The pencil hardness was 2H. The refractive index of the low refractive index layer was 1.41.
[Liquid crystal display device 8]
Then, a liquid crystal display device 8 was produced in the same manner as in Example 1 except that the output side polarizer P8 was used instead of the output side polarizer P1 obtained in Example 1.
When the display characteristics of the obtained liquid crystal display device 8 were visually evaluated, under an environment of 500 lux or more, reflection was seen on the screen, the black display quality was poor, and the contrast was low. The evaluation results of the obtained liquid crystal display device 8 are shown in Table 1.

(Comparative Example 4) (Production of liquid crystal display device 9)
[Emission-side polarizer P9]
In the same manner as in Example 1, except that the low refractive index layer forming composition L4 obtained in Production Example 10 was used instead of the low refractive index layer forming composition L1 obtained in Production Example 7, An exit side polarizer P9 was obtained. The pencil hardness was 2H. The refractive index of the low refractive index layer was 1.43.
[Liquid crystal display device 8]
Then, a liquid crystal display device 9 was produced in the same manner as in Example 1 except that the above-described output side polarizer P9 was used instead of the output side polarizer P1 obtained in Example 1.
When the display characteristics of the obtained liquid crystal display device 9 were visually evaluated, under an environment of 500 lux or more, reflection was seen on the screen, the black display quality was poor, and the contrast was low. The evaluation results of the obtained liquid crystal display device 9 are shown in Table 1.

It is an explanatory view of a measuring method of retardation R _40. It is explanatory drawing of the one aspect | mode of the liquid crystal display device of this invention. It is explanatory drawing of the other aspect of the liquid crystal display device of this invention. It is explanatory drawing of the other aspect of the liquid crystal display device of this invention. It is explanatory drawing of the other aspect of the liquid crystal display device of this invention. It is explanatory drawing of the one aspect | mode of the conventional liquid crystal display device. It is explanatory drawing of the other aspect of the conventional liquid crystal display device.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Incident side polarizer 2 Liquid crystal cell 3 Optical anisotropic plate 4 Optical anisotropic plate 5 Outgoing side polarizer

Claims (5)

Between a pair of polarizers composed of an exit-side polarizer and an entrance-side polarizer whose respective absorption axes are substantially perpendicular to each other, k optical anisotropic plates (k is an integer of 2 or more) and An in-plane switching mode liquid crystal display device having a liquid crystal cell,
The number of the optical anisotropic plate is i, the main refractive index in the surface of the i-th optical anisotropic plate is n _ix , n _iy (where n _ix > n _iy ), and the main refractive index in the thickness direction. _Where n _iz is
(Σn _ix + Σn _iy ) / 2 ≦ Σn _iz
(Where Σ represents the sum of i = 1 to k),
In the optical laminated plate (O) formed by laminating the optical anisotropic plate and the liquid crystal cell, the retardation when light having a wavelength of 550 nm is perpendicularly incident is R ₀ , and the light having a wavelength of 550 nm is from the normal to the main axis direction. When the retardation when incident at an angle of 40 degrees is R ₄₀ ,
0.90 <R ₄₀ / R ₀ <1.10
And satisfy the relationship
An antireflection plate is provided on the observation side of the output side polarizer,
The antireflection plate is
Hollow particles (A) having a particle size of 5 to 2000 nm,
A siloxane oligomer (B) having a (meth) acryloyl group and a fluoroalkyl group, and
Acrylate compound (C) having (meth) acryloyl group
A liquid crystal display device comprising a low refractive index layer comprising a cured film of a composition comprising: 2. The liquid crystal display device according to claim 1, wherein a refractive index of the low refractive index layer is 1.40 or less. 3. The liquid crystal display device according to claim 1, wherein at least one of the optical anisotropic plates is a layer containing a resin having a negative intrinsic birefringence. 3. The liquid crystal display device according to claim 1, wherein at least one of the optical anisotropic plates is a layer containing discotic liquid crystal molecules or lyotropic liquid crystal molecules. The liquid crystal display device according to claim 1, wherein at least one of the optical anisotropic plates is a layer containing a photoisomerization substance.

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