WO2020137409A1 - Optically anisotropic laminate, method for manufacturing same, circularly polarizing plate, and image display device - Google Patents

Optically anisotropic laminate, method for manufacturing same, circularly polarizing plate, and image display device Download PDF

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Publication number
WO2020137409A1
WO2020137409A1 PCT/JP2019/047519 JP2019047519W WO2020137409A1 WO 2020137409 A1 WO2020137409 A1 WO 2020137409A1 JP 2019047519 W JP2019047519 W JP 2019047519W WO 2020137409 A1 WO2020137409 A1 WO 2020137409A1
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Prior art keywords
optically anisotropic
anisotropic layer
layer
resin
laminate
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PCT/JP2019/047519
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French (fr)
Japanese (ja)
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和弘 大里
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日本ゼオン株式会社
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Priority to KR1020217017868A priority Critical patent/KR20210107650A/en
Priority to CN201980083873.4A priority patent/CN113196876A/en
Priority to JP2020562994A priority patent/JP7452436B2/en
Publication of WO2020137409A1 publication Critical patent/WO2020137409A1/en

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    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K59/00—Integrated devices, or assemblies of multiple devices, comprising at least one organic light-emitting element covered by group H10K50/00
    • H10K59/80—Constructional details
    • H10K59/8791—Arrangements for improving contrast, e.g. preventing reflection of ambient light
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B33/00—Electroluminescent light sources
    • H05B33/02—Details
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B7/00—Layered products characterised by the relation between layers; Layered products characterised by the relative orientation of features between layers, or by the relative values of a measurable parameter between layers, i.e. products comprising layers having different physical, chemical or physicochemical properties; Layered products characterised by the interconnection of layers
    • B32B7/02—Physical, chemical or physicochemical properties
    • B32B7/023—Optical properties
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/30—Polarising elements
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09F—DISPLAYING; ADVERTISING; SIGNS; LABELS OR NAME-PLATES; SEALS
    • G09F9/00—Indicating arrangements for variable information in which the information is built-up on a support by selection or combination of individual elements
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09F—DISPLAYING; ADVERTISING; SIGNS; LABELS OR NAME-PLATES; SEALS
    • G09F9/00—Indicating arrangements for variable information in which the information is built-up on a support by selection or combination of individual elements
    • G09F9/30—Indicating arrangements for variable information in which the information is built-up on a support by selection or combination of individual elements in which the desired character or characters are formed by combining individual elements

Definitions

  • the present invention relates to an optically anisotropic laminate, a method for manufacturing the same, a circularly polarizing plate, and an image display device.
  • Image display devices such as organic electroluminescence image display devices may reduce the quality of image display by reflecting external light.
  • organic electroluminescence may be referred to as “organic EL”.
  • organic EL organic electroluminescence
  • a circularly polarizing plate may be provided on the display surface of the image display device (for example, see Patent Document 1).
  • External light is converted into circularly polarized light in a certain direction by the circularly polarizing plate, and becomes circularly polarized light in the opposite direction when reflected by the image display device. Since the reflected light that has become circularly polarized light in the opposite direction does not pass through the circularly polarizing plate, reflection is suppressed.
  • the circularly polarizing plate includes a linear polarizer, a ⁇ /2 plate having a slow axis in a direction forming a predetermined angle with respect to the absorption axis of the linear polarizer, and an absorption axis of the linear polarizer. And a ⁇ /4 plate having a slow axis in a direction forming a predetermined angle with respect to the ⁇ /2 plate, the wavelength dispersion of the ⁇ /2 plate and the wavelength dispersion of the ⁇ /4 plate are different, and the NZ of the ⁇ /4 plate is It is described that reflection can be effectively suppressed by providing a configuration in which the coefficient is a predetermined value. However, even when such a circularly polarizing plate is provided on the display surface of the image display device, when the display surface is observed from the tilt direction, the light reflected by the display surface is visually recognized, and thus the display surface is colored. I could see it.
  • a circularly polarizing plate is a ⁇ /4 plate produced by laminating a linear polarizer and two stretched films in parallel with their slow axes in parallel, and by setting the NZ coefficient to a predetermined value, It is described that reflection can be suppressed.
  • the reflection suppressing effect is insufficient when the display surface is observed from the front direction and the tilt direction, and the display surface looks colored. There was something.
  • the optical anisotropy including a first optical anisotropic layer satisfying a predetermined optical condition and a second optical anisotropic layer satisfying a predetermined optical condition.
  • the sum of the NZ coefficient NZ1 of the first optically anisotropic layer and the NZ coefficient NZ2 of the second optically anisotropic layer is within a predetermined range, and the slow axis of the first optically anisotropic layer is
  • the present invention has been completed by finding that the above problems can be solved by adopting a mode in which the slow axis of the second optically anisotropic layer is orthogonal to the above. That is, the present invention provides the following.
  • An optically anisotropic laminate including a first optically anisotropic layer and a second optically anisotropic layer,
  • the first optically anisotropic layer satisfies the following formula (1)
  • the second optically anisotropic layer satisfies the following formula (2)
  • the optically anisotropic laminate satisfies the following formula (3)
  • the NZ coefficient NZ1 of the first optically anisotropic layer and the NZ coefficient NZ2 of the second optically anisotropic layer satisfy the following formula (4)
  • An optically anisotropic laminate, wherein an angle formed by the slow axis of the first optically anisotropic layer and the slow axis of the second optically anisotropic layer is 85° to 95°.
  • nx1 represents the in-plane direction of the first optically anisotropic layer and represents the refractive index in the direction that gives the maximum refractive index
  • ny1 represents the in-plane direction of the first optically anisotropic layer
  • nx1 represents the refractive index in the direction orthogonal to the direction
  • nz1 represents the refractive index in the thickness direction of the first optical anisotropic layer
  • nx2 represents an in-plane direction of the second optically anisotropic layer and represents a refractive index in a direction that gives the maximum refractive index
  • ny2 represents an in-plane direction of the second optically anisotropic layer
  • nx2 represents the refractive index in the direction orthogonal to
  • the first optically anisotropic layer is a stretched film of a first resin film, The optically anisotropic laminate according to any one of [1] to [3], wherein the first resin film contains a resin having a positive intrinsic birefringence value.
  • the second optically anisotropic layer is a stretched film of a second resin film, The optically anisotropic laminate according to any one of [1] to [5], wherein the second resin film contains a resin having a negative intrinsic birefringence value.
  • the second optically anisotropic layer is a stretched film obtained by stretching the second resin film in two directions, and the NZ2 is ⁇ 2.0 or more and ⁇ 0.2 or less. Optically anisotropic laminate.
  • a linear polarizer, A circularly polarizing plate comprising: the optically anisotropic laminate according to any one of [1] to [7].
  • the angle between the absorption axis of the linear polarizer or the transmission axis of the linear polarizer and the slow axis of the first optically anisotropic layer is 40° to 50°. Circular polarizing plate.
  • the linear polarizer, the first optically anisotropic layer, and the second optically anisotropic layer are provided in this order, or The circularly polarizing plate according to [8] or [9], which includes the linear polarizer, the second optically anisotropic layer, and the first optically anisotropic layer in this order.
  • An image display device comprising the circularly polarizing plate according to any one of [8] to [10] and an organic electroluminescence element, An image display device comprising: the linear polarizer, the optically anisotropic laminate, and the organic electroluminescent element in this order.
  • the image display apparatus which suppressed the coloring of the display surface seen from the inclination direction can be implement
  • FIG. 1 is an exploded perspective view schematically showing the circularly polarizing plate according to the first embodiment.
  • FIG. 2 is an exploded perspective view schematically showing the circularly polarizing plate according to the second embodiment.
  • FIG. 3 is a perspective view schematically showing a state of the evaluation model set when the chromaticity is calculated in the simulations of the example and the comparative example.
  • the “long” film means a film having a length of 5 times or more with respect to the width, preferably having a length of 10 times or more, and specifically, a roll.
  • a film having a length such that the film is wound into a shape and stored or transported.
  • the upper limit of the length of the long film is not particularly limited and may be, for example, 100,000 times or less the width.
  • nx represents the refractive index in the direction perpendicular to the thickness direction of the layer (in-plane direction) and giving the maximum refractive index (slow axis direction), and ny represents the in-plane direction of the layer.
  • nz represents the refractive index in the thickness direction of the layer, and d represents the thickness of the layer.
  • the measurement wavelength is 590 nm unless otherwise specified.
  • the slow axis of a layer indicates the in-plane slow axis of the layer unless otherwise specified.
  • the frontal direction of a surface means the normal direction of the surface unless specifically stated otherwise, and specifically refers to the direction with the polar angle of 0° and the azimuth angle of 0°.
  • the inclination direction of a surface means a direction that is neither parallel nor perpendicular to the surface unless specifically stated otherwise, and specifically, a range in which the polar angle of the surface is larger than 0° and smaller than 90°. Point in the direction of.
  • the terms “parallel”, “vertical”, and “orthogonal” of the directions of elements include an error within a range that does not impair the effects of the present invention, for example, a range of ⁇ 5°, unless otherwise specified. You can leave.
  • the longitudinal direction of the long film is usually parallel to the film flow direction in the production line.
  • polarizing plate “circular polarizing plate”, “plate”, and “ ⁇ /2 plate” and “ ⁇ /4 plate” are not limited to rigid members, for example, unless otherwise specified. It also includes a flexible member such as a resin film.
  • the angle formed by the optical axis (absorption axis, transmission axis, slow axis, etc.) of each layer in a member including a plurality of layers is the angle when the layer is viewed from the thickness direction unless otherwise specified. Represents.
  • polymer having a positive intrinsic birefringence value and “resin having a positive intrinsic birefringence value” means “the refractive index in the stretching direction is more than the refractive index in the direction orthogonal to the stretching direction. It means a “polymer which becomes larger” and “a resin whose refractive index in the stretching direction is larger than that in the direction orthogonal to the stretching direction", respectively.
  • a polymer having a negative intrinsic birefringence value and “a resin having a negative intrinsic birefringence value” mean that a polymer having a refractive index in the stretching direction smaller than that in the direction orthogonal to the stretching direction. It means “combined” and “resin whose refractive index in the stretching direction is smaller than that in the direction orthogonal to the stretching direction", respectively.
  • the intrinsic birefringence value can be calculated from the dielectric constant distribution.
  • the adhesive includes not only an adhesive in a narrow sense, but also an adhesive having a shear storage elastic modulus at 23° C. of less than 1 MPa.
  • the adhesive in a narrow sense means an adhesive having a shear storage elastic modulus at 23° C. of 1 MPa to 500 MPa after irradiation with energy rays or after heat treatment.
  • FIG. 1 is an exploded perspective view schematically showing the circularly polarizing plate according to the first embodiment.
  • the circularly polarizing plate 500 of this embodiment includes a linear polarizer 130 and the optically anisotropic laminate 100 of this embodiment.
  • the optically anisotropic layered product 100 of this embodiment includes a first optically anisotropic layer 110 and a second optically anisotropic layer 120.
  • the optically anisotropic layered product 100 may include any layer (not shown) as necessary.
  • the first optically anisotropic layer 110 satisfies the following formula (1)
  • the second optically anisotropic layer 120 satisfies the following formula (2)
  • the optically anisotropic laminate 100 is Formula (3) is satisfied
  • the first optical anisotropic layer and the second optical anisotropic layer satisfy the following formula (4)
  • the slow axis 111 of the first optical anisotropic layer 110 and the second optical anisotropic layer 110 The angle formed by the slow axis 121 of the anisotropic layer 120 is 85° to 95°.
  • Angles formed by the slow axis 111 of the first optically anisotropic layer 110 and the slow axis 121 of the second optically anisotropic layer 120 which have optical characteristics satisfying the equations (1) to (4).
  • the circularly polarizing plate 500 obtained by combining the optically anisotropic laminate 100 having an angle of 85° to 95° with the linear polarizer 130 in the image display device, the display surface of the image display device is tilted from the tilt direction. When viewed, the reflection of external light can be suppressed, and coloring can be effectively suppressed.
  • nx1 represents a refractive index in the in-plane direction of the first optically anisotropic layer, which gives the maximum refractive index
  • ny1 represents in-plane of the first optically anisotropic layer.
  • Direction which is the refractive index in the direction orthogonal to the direction that gives nx1
  • nz1 represents the refractive index in the thickness direction of the first optically anisotropic layer.
  • the above formula (1) shows that the first optically anisotropic layer can function as a so-called positive A plate or negative B plate.
  • the color of the display surface after the heating test is It is possible to easily realize an image display device in which the change in taste is suppressed.
  • nx2 represents the refractive index in the in-plane direction of the second optically anisotropic layer, which gives the maximum refractive index
  • ny2 represents the in-plane direction of the second optically anisotropic layer.
  • Direction which is the refractive index in the direction orthogonal to the direction that gives nx2
  • nz2 represents the refractive index in the thickness direction of the second optically anisotropic layer.
  • the above formula (2) shows that the second optically anisotropic layer can function as a so-called positive B plate.
  • the second optically anisotropic layer satisfies the expression (2), it is possible to realize an image display device that can effectively suppress coloring due to reflected light.
  • Formula (2) indicates that the second optically anisotropic layer is a layer having different refractive indices (nx2, ny2, and nz2) in three directions, that is, a layer having biaxiality.
  • Re(450), Re(550) and Re(650) represent the in-plane retardation of the optically anisotropic laminate at wavelengths of 450 nm, 550 nm and 650 nm, respectively.
  • the above formula (3) shows that the in-plane retardation of the optically anisotropic laminate has inverse wavelength dispersion.
  • the optically anisotropic laminate can uniformly convert the polarization state of light transmitted through the optically anisotropic laminate in a wide wavelength range. Therefore, it is possible to realize an image display device capable of effectively suppressing coloring due to reflected light in a wide wavelength range.
  • NZ1 represents the NZ coefficient of the first optically anisotropic layer
  • NZ2 represents the NZ coefficient of the second optically anisotropic layer.
  • the sum of NZ1 and NZ2 is ⁇ 0.3 or more, preferably 0 or more, more preferably 0.15 or more, and 0.8 or less, preferably 0.75 or less, more preferably 0.65 or less. Is.
  • NZ1 is a value calculated by (nx1-nz1)/(nx1-ny1), and from equation (1), NZ1 is a positive value.
  • NZ1 is preferably 1.0 or more, more preferably 1.05 or more, preferably 1.3 or less, more preferably 1.2 or less.
  • NZ2 is a value calculated by (nx2-nz2)/(nx2-ny2), and from equation (2), NZ2 is a negative value.
  • NZ2 is preferably ⁇ 2.0 or more, more preferably ⁇ 1.5 or more, preferably ⁇ 0.2 or less, more preferably ⁇ 0.4 or less.
  • the first optically anisotropic layer and the second optically anisotropic layer have optical characteristics that satisfy the following formulas (5) and (6).
  • Re1 (550) represents the in-plane retardation of the first optically anisotropic layer at a wavelength of 550 nm
  • Re1 (450) is the in-plane position of the first optically anisotropic layer at a wavelength of 450 nm
  • Re2 (550) represents the in-plane retardation of the second optically anisotropic layer at a wavelength of 550 nm
  • Re2 (450) represents the in-plane retardation of the second optically anisotropic layer at a wavelength of 450 nm. ..
  • the above formula (5) shows that the wavelength dispersion of the second optically anisotropic layer is larger than that of the first optically anisotropic layer.
  • Re1 (550) represents the in-plane retardation of the first optically anisotropic layer at a wavelength of 550 nm
  • Re2 (550) is the in-plane retardation of the second optically anisotropic layer at a wavelength of 550 nm.
  • Formula (6) shows that Re1 (550) of the first optically anisotropic layer is larger than Re2 (550) of the second optically anisotropic layer.
  • the difference between Re1 (550) and Re2 (550) is preferably 100 nm or more, more preferably 110 nm or more, preferably 180 nm or less, more preferably 160 nm or less.
  • the in-plane retardation Re1 (590) of the first optically anisotropic layer at a wavelength of 590 nm is preferably 240 nm or more, more preferably 260 nm or more, preferably 320 nm or less, more preferably 300 nm or less.
  • an image display device capable of more effectively suppressing coloring of reflected light when the display surface is viewed from the tilt direction is provided. realizable.
  • the in-plane retardation Re2 (590) of the second optically anisotropic layer at a wavelength of 590 nm is preferably 100 nm or more, more preferably 120 nm or more, preferably 190 nm or less, more preferably 170 nm or less.
  • an image display device that can more effectively suppress coloring due to reflected light when the display surface is viewed from the tilt direction is realized. it can.
  • the total light transmittance of the first optically anisotropic layer is preferably 80% or more, more preferably 85% or more, and particularly preferably 90% or more.
  • the total light transmittance of the second optically anisotropic layer is preferably 80% or more, more preferably 85% or more, and particularly preferably 90% or more.
  • the haze of the first optically anisotropic layer is preferably 5% or less, more preferably 3% or less, particularly preferably 1% or less, and ideally 0%.
  • the haze of the second optically anisotropic layer is preferably 5% or less, more preferably 3% or less, particularly preferably 1% or less, and ideally 0%.
  • the thickness of the first optically anisotropic layer and the thickness of the second optically anisotropic layer can be arbitrarily adjusted within the range having the above optical characteristics.
  • the thickness of the first optically anisotropic layer is preferably 0.5 ⁇ m or more, more preferably 1 ⁇ m or more, preferably 150 ⁇ m or less, more preferably 100 ⁇ m or less.
  • the thickness of the second optically anisotropic layer is preferably 0.5 ⁇ m or more, more preferably 1 ⁇ m or more, preferably 150 ⁇ m or less, more preferably 100 ⁇ m or less.
  • the total light transmittance of the optically anisotropic laminate is preferably 80% or more, more preferably 85% or more, and particularly preferably 90% or more.
  • the haze of the optically anisotropic laminate is preferably 5% or less, more preferably 3% or less, particularly preferably 1% or less, and ideally 0%.
  • the thickness of the optically anisotropic laminate can be arbitrarily adjusted within the range having the above optical characteristics.
  • the specific thickness is preferably 5 ⁇ m or more, more preferably 10 ⁇ m or more, particularly preferably 15 ⁇ m or more, preferably 200 ⁇ m or less, more preferably 150 ⁇ m or less, particularly preferably 100 ⁇ m or less.
  • a resin can be mentioned, and among them, a thermoplastic resin is preferable.
  • a resin containing a polymer having a positive intrinsic birefringence value has a negative intrinsic birefringence value. It may be a resin containing a polymer, or a resin containing a polymer having a positive intrinsic birefringence value and a polymer having a negative intrinsic birefringence value.
  • the polymer having a positive intrinsic birefringence value is not particularly limited, but examples thereof include polyolefins such as polyethylene and polypropylene; polyesters such as polyethylene terephthalate and polybutylene terephthalate; polyarylene sulfides such as polyphenylene sulfide; polyvinyl alcohol; polycarbonate; Polyarylate; cellulose ester, polyether sulfone, polysulfone, polyaryl sulfone, polyvinyl chloride, alicyclic structure-containing polymers such as cyclic olefin polymers and norbornene polymers, and rod-shaped liquid crystal polymers.
  • polyolefins such as polyethylene and polypropylene
  • polyesters such as polyethylene terephthalate and polybutylene terephthalate
  • polyarylene sulfides such as polyphenylene sulfide
  • polyvinyl alcohol polycarbonate
  • Polyarylate cellulose ester
  • the polymer having a negative intrinsic birefringence value is not particularly limited, but for example, a homopolymer of a styrene compound, and a polystyrene polymer including a copolymer of a styrene compound and an arbitrary monomer; Examples thereof include an acrylonitrile polymer; a polymethylmethacrylate polymer; or a polycopolymer of these.
  • Examples of the arbitrary monomer copolymerizable with the styrene compound include acrylonitrile, maleic anhydride, methyl methacrylate, and butadiene, and one selected from acrylonitrile, maleic anhydride, methyl methacrylate, and butadiene. The above is preferable.
  • the above-mentioned polymer may be a homopolymer or a copolymer. Moreover, the said polymer may be used individually by 1 type, and may be used in combination of 2 or more types in arbitrary ratios.
  • the resin for forming the first optically anisotropic layer and the second optically anisotropic layer may contain an optional compounding agent in addition to the polymer.
  • the compounding agent include stabilizers such as antioxidants, heat stabilizers, light stabilizers, weather resistance stabilizers, ultraviolet absorbers and near infrared absorbers; plasticizers and the like.
  • the compounding agent one kind may be used, or two or more kinds may be used in combination at an arbitrary ratio.
  • the first optically anisotropic layer may be a layer including a liquid crystal alignment layer.
  • the liquid crystal alignment layer will be described in [1-3-2].
  • the first optically anisotropic layer may be a stretched film of the first resin film.
  • the first resin film preferably contains a resin having a positive intrinsic birefringence value.
  • the resin having such a positive intrinsic birefringence value include a resin containing an alicyclic structure-containing polymer, a resin containing cellulose ester, and a resin containing polycarbonate.
  • the first resin film more preferably contains at least one selected from a resin containing an alicyclic structure-containing polymer, a resin containing a cellulose ester, and a resin containing a polycarbonate.
  • the first optically anisotropic layer may be a layer formed by stretching a film (first resin film) made of a resin having a positive intrinsic birefringence value.
  • the first resin film refers to a resin film that has not yet been stretched to form the first optically anisotropic layer.
  • the alicyclic structure-containing polymer is a polymer having an alicyclic structure in the repeating unit, and is usually an amorphous polymer.
  • As the alicyclic structure-containing polymer both a polymer having an alicyclic structure in its main chain and a polymer having an alicyclic structure in its side chain can be used.
  • Examples of the alicyclic structure include a cycloalkane structure and a cycloalkene structure, and the cycloalkane structure is preferable from the viewpoint of thermal stability and the like.
  • the number of carbon atoms constituting one repeating unit of the alicyclic structure is not particularly limited, but preferably 4 or more, more preferably 5 or more, particularly preferably 6 or more, preferably 30 or less, The number is more preferably 20 or less, and particularly preferably 15 or less.
  • the proportion of repeating units having an alicyclic structure in the alicyclic structure-containing polymer may be appropriately selected according to the purpose of use, but is preferably 50% by weight or more, more preferably 70% by weight or more, particularly preferably It is 90% by weight or more.
  • Examples of the alicyclic structure-containing polymer include (1) norbornene polymer, (2) monocyclic cycloolefin polymer, (3) cyclic conjugated diene polymer, (4) vinyl alicyclic hydrocarbon polymer, And hydrogenated products thereof.
  • a cyclic olefin polymer and a norbornene polymer are more preferable.
  • Examples of the norbornene polymer include ring-opening polymers of norbornene monomers, ring-opening copolymers of norbornene monomers with other monomers capable of ring-opening copolymerization, and hydrogenated products thereof; addition polymers of norbornene monomers, Examples thereof include addition copolymers of norbornene monomers and other monomers copolymerizable therewith.
  • a hydrogenated product of a ring-opening polymer of a norbornene monomer is particularly preferable from the viewpoint of transparency.
  • the alicyclic structure-containing polymer is selected from known polymers disclosed in, for example, JP-A-2002-321302.
  • a lower fatty acid ester of cellulose eg, cellulose acetate, cellulose acetate butyrate and cellulose acetate propionate
  • the lower fatty acid means a fatty acid having 6 or less carbon atoms per molecule.
  • Cellulose acetate includes triacetyl cellulose (TAC) and cellulose diacetate (DAC).
  • the total acyl group substitution degree of the cellulose ester is preferably 2.20 or more and 2.70 or less, and more preferably 2.40 or more and 2.60 or less.
  • the total acyl group can be measured according to ASTM D817-91.
  • the weight average degree of polymerization of the cellulose ester is preferably 350 or more and 800 or less, more preferably 370 or more and 600 or less.
  • the number average molecular weight of the cellulose ester is preferably 60,000 or more and 230,000 or less, more preferably 70,000 or more and 230,000 or less.
  • polycarbonate examples include polymers having a structural unit derived from a dihydroxy compound and a carbonate structure (a structure represented by —O—(C ⁇ O)—O—).
  • dihydroxy compound examples include bisphenol A.
  • the constitutional unit derived from the dihydroxy compound contained in the polycarbonate may be one type or two or more types.
  • the first optically anisotropic layer contains a resin containing triacetyl cellulose. Since the retardation of a film formed of a resin containing triacetyl cellulose generally has a reverse wavelength dispersibility, it is possible to realize an image display device that can more effectively suppress coloring due to reflected light in a wide wavelength range.
  • the first optically anisotropic layer is made of a resin containing triacetyl cellulose
  • the first optically anisotropic layer is preferably a layer formed by a solution casting method. Thereby, the first optically anisotropic layer satisfying the formula (1) can be easily manufactured.
  • the first optically anisotropic layer may be a layer including a liquid crystal alignment layer.
  • the liquid crystal alignment layer is a cured product layer obtained by curing a layer of a liquid crystal composition containing an aligned liquid crystal compound. Therefore, since the liquid crystal alignment layer is formed of the cured product of the liquid crystal composition, it contains molecules of the liquid crystal compound.
  • the liquid crystal compound preferably has polymerizability. Therefore, the liquid crystal compound preferably has a molecule containing a polymerizable group such as an acryloyl group, a methacryloyl group, and an epoxy group.
  • the number of polymerizable groups per molecule of the liquid crystal compound may be one, but is preferably two or more.
  • the polymerizable liquid crystal compound can be polymerized in a state of exhibiting a liquid crystal phase so as not to change the direction of the maximum refractive index in the refractive index ellipsoid of the molecules in the liquid crystal phase. Therefore, it is possible to fix the alignment state of the liquid crystal compound in the liquid crystal alignment layer or increase the polymerization degree of the liquid crystal compound to enhance the mechanical strength of the liquid crystal alignment layer.
  • the molecular weight of the liquid crystal compound is preferably 300 or more, more preferably 500 or more, particularly preferably 800 or more, preferably 2000 or less, more preferably 1700 or less, and particularly preferably 1500 or less.
  • a liquid crystal compound having a molecular weight in such a range is used, the coatability of the liquid crystal composition can be made particularly good.
  • the birefringence ⁇ n of the liquid crystal compound at a measurement wavelength of 590 nm is preferably 0.01 or more, more preferably 0.03 or more, preferably 0.15 or less, more preferably 0.10.
  • a liquid crystal compound having a birefringence ⁇ n in such a range is used, it is easy to obtain a liquid crystal cured layer with few alignment defects.
  • the liquid crystal compound may be used alone or in combination of two or more kinds at an arbitrary ratio.
  • liquid crystal compounds examples include liquid crystal compounds represented by the following formula (I).
  • Ar has at least one of an aromatic heterocycle, a heterocycle, and an aromatic hydrocarbon ring, and is an optionally substituted divalent organic group having 6 to 67 carbon atoms.
  • aromatic heterocycle include 1H-isoindole-1,3(2H)-dione ring, 1-benzofuran ring, 2-benzofuran ring, acridine ring, isoquinoline ring, imidazole ring, indole ring, oxadiazole ring.
  • a 1 , A 2 , B 1 and B 2 are each independently a cyclic aliphatic group which may have a substituent, and an aromatic group which may have a substituent.
  • the number of carbon atoms of the group represented by A 1 , A 2 , B 1 and B 2 (including the number of carbon atoms of the substituent) is usually 3 to 100 each independently.
  • a 1 , A 2 , B 1 and B 2 each independently have a cycloaliphatic group having 5 to 20 carbon atoms which may have a substituent, or a substituent.
  • Aromatic groups having 2 to 20 carbon atoms are preferable.
  • Examples of the cycloaliphatic group for A 1 , A 2 , B 1 and B 2 include a cyclopentane-1,3-diyl group, a cyclohexane-1,4-diyl group, a cycloheptane-1,4-diyl group, Cycloalkanediyl group having 5 to 20 carbon atoms such as cyclooctane-1,5-diyl group; carbon atom such as decahydronaphthalene-1,5-diyl group, decahydronaphthalene-2,6-diyl group A bicycloalkanediyl group of the number 5 to 20; and the like.
  • an optionally substituted cycloalkanediyl group having 5 to 20 carbon atoms is preferable, a cyclohexanediyl group is more preferable, and a cyclohexane-1,4-diyl group is particularly preferable.
  • the cycloaliphatic group may be in trans form, cis form, or a mixture of cis form and trans form. Among them, the trans form is more preferable.
  • Examples of the substituent that the cycloaliphatic group in A 1 , A 2 , B 1 and B 2 may have include a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, Examples thereof include a nitro group and a cyano group.
  • the number of substituents may be one or more. Further, the plurality of substituents may be the same as or different from each other.
  • Examples of the aromatic group for A 1 , A 2 , B 1 and B 2 include 1,2-phenylene group, 1,3-phenylene group, 1,4-phenylene group, 1,4-naphthylene group, 1, Aromatic hydrocarbon ring group having 6 to 20 carbon atoms such as 5-naphthylene group, 2,6-naphthylene group, 4,4'-biphenylene group; furan-2,5-diyl group, thiophene-2,5 -Diyl group, pyridine-2,5-diyl group, pyrazine-2,5-diyl group and the like; aromatic heterocyclic group having 2 to 20 carbon atoms; and the like.
  • an aromatic hydrocarbon ring group having 6 to 20 carbon atoms is preferable, a phenylene group is more preferable, and a 1,4-phenylene group is particularly preferable.
  • the substituent which the aromatic group in A 1 , A 2 , B 1 and B 2 may have is, for example, the same as the substituent which the cyclic aliphatic group in A 1 , A 2 , B 1 and B 2 may have.
  • An example is given.
  • the number of substituents may be one or more. Further, the plurality of substituents may be the same as or different from each other.
  • R 22 and R 23 each independently represent a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.
  • G 1 and G 2 are each independently an aliphatic hydrocarbon group having 1 to 20 carbon atoms; and a methylene group contained in the aliphatic hydrocarbon group having 3 to 20 carbon atoms.
  • the hydrogen atom contained in the organic group of G 1 and G 2 may be substituted with an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, or a halogen atom.
  • the methylene groups (—CH 2 —) at both ends of G 1 and G 2 are not replaced with —O— or —C( ⁇ O)—.
  • Specific examples of the aliphatic hydrocarbon group having 1 to 20 carbon atoms in G 1 and G 2 include an alkylene group having 1 to 20 carbon atoms.
  • Specific examples of the aliphatic hydrocarbon group having 3 to 20 carbon atoms in G 1 and G 2 include an alkylene group having 3 to 20 carbon atoms.
  • P 1 and P 2 each independently represent a polymerizable group.
  • the polymerizable group for P 1 and P 2 include a group represented by CH 2 ⁇ CR 31 —C( ⁇ O)—O— such as an acryloyloxy group and a methacryloyloxy group; a vinyl group; a vinyl ether group; p-stilbene group; acryloyl group; methacryloyl group; carboxyl group; methylcarbonyl group; hydroxyl group; amide group; alkylamino group having 1 to 4 carbon atoms; amino group; epoxy group; oxetanyl group; aldehyde group; isocyanate group; thio Isocyanate group; and the like.
  • R 31 represents a hydrogen atom, a methyl group, or a chlorine atom.
  • the liquid crystal compound represented by the formula (I) can be produced, for example, by the reaction of a hydrazine compound and a carbonyl compound described in WO2012/147904.
  • liquid crystal compound represented by the formula (I) include compounds represented by the following formulas.
  • the liquid crystal composition may further contain an optional component in combination with the liquid crystal compound, if necessary.
  • an optional component in combination with the liquid crystal compound, if necessary.
  • the arbitrary component one type may be used alone, or two or more types may be used in combination at an arbitrary ratio.
  • the liquid crystal composition may contain a polymerization initiator as an optional component.
  • a polymerization initiator either a thermal polymerization initiator or a photopolymerization initiator may be used.
  • the liquid crystal composition may include a surfactant as an optional component.
  • the surfactant is preferably a surfactant containing a fluorine atom in the molecule.
  • the liquid crystal composition may include, for example, an antioxidant as an optional component.
  • an antioxidant By using an antioxidant, gelation of the liquid crystal composition can be suppressed, so that the pot life of the liquid crystal composition can be extended.
  • the antioxidant one kind may be used alone, and two kinds may be used in combination at an arbitrary ratio.
  • the liquid crystal composition may include a solvent as an optional component.
  • a solvent those capable of dissolving the reverse dispersion liquid crystal compound are preferable.
  • An organic solvent is usually used as such a solvent.
  • liquid crystal composition may include include metals; metal complexes; metal oxides such as titanium oxide; coloring agents such as dyes and pigments; luminescent materials such as fluorescent materials and phosphorescent materials; leveling agents; Examples include thixotropic agents, gelling agents, polysaccharides, ultraviolet absorbers, infrared absorbers, antioxidants, ion exchange resins, and the like. The amount of each of these components may be 0.1 to 20 parts by weight based on 100 parts by weight of the liquid crystal compound.
  • the curing of the liquid crystal composition is usually achieved by polymerizing the polymerizable compound contained in the liquid crystal composition. Therefore, the liquid crystal alignment layer usually contains a polymer of a part or all of the components included in the liquid crystal composition. Therefore, when the liquid crystal compound is polymerizable, the liquid crystal alignment layer may be a layer containing a polymer of the liquid crystal compound. Usually, the liquid crystallinity of the liquid crystal compound is lost by polymerization, but in the present application, the liquid crystal compound thus polymerized is also included in the term “liquid crystal compound contained in the liquid crystal alignment layer”.
  • liquid crystal alignment layer In the liquid crystal alignment layer, the fluidity of the liquid crystal composition is lost. Therefore, usually, in the liquid crystal alignment layer, the alignment state of the liquid crystal compound can be fixed.
  • liquid crystal compound having a fixed alignment state includes a polymer of the above liquid crystal compound.
  • the liquid crystal alignment layer may include molecules of the liquid crystal compound in which the alignment state is not fixed by combining with molecules of the liquid crystal compound in which the alignment state is fixed, but all of the molecules of the liquid crystal compound included in the liquid crystal alignment layer are included. It is preferable that the orientation state is fixed.
  • the method for forming the liquid crystal alignment layer is not particularly limited, for example, a film serving as a base material, a step of forming a layer of a liquid crystal composition containing a liquid crystal compound, a step of aligning the liquid crystal compound contained in the layer of the liquid crystal composition, Alternatively, it can be formed by performing a step of curing the layer of the liquid crystal composition.
  • the second optically anisotropic layer may be a stretched film of the second resin film.
  • the second resin film preferably contains a resin having a negative intrinsic birefringence value.
  • the second resin film formed of the resin can be stretched to easily produce the second optically anisotropic layer satisfying the formula (2). Therefore, the second optically anisotropic layer may be a layer formed by stretching a film (second resin film) made of a resin having a negative intrinsic birefringence value.
  • the second resin film refers to the resin film that has not yet been stretched to form the second optically anisotropic layer.
  • the resin having a negative intrinsic birefringence value includes a polymer having a negative intrinsic birefringence value.
  • a polystyrene polymer is preferable, and in terms of high heat resistance, styrene or a styrene derivative and maleic anhydride Copolymers are particularly preferred.
  • the amount of the maleic anhydride unit is preferably 5 parts by weight or more, more preferably 10 parts by weight or more, particularly preferably 15 parts by weight or more, and preferably 30 parts by weight with respect to 100 parts by weight of the polystyrene polymer. It is not more than 28 parts by weight, more preferably not more than 28 parts by weight, particularly preferably not more than 26 parts by weight.
  • the maleic anhydride unit is a structural unit having a structure formed by polymerizing maleic anhydride.
  • the proportion of the polymer in the resin having a negative intrinsic birefringence value is preferably 50% by weight to 100% by weight, more preferably 70% by weight to 100% by weight, and particularly preferably 90% by weight to 100% by weight.
  • the second optically anisotropic layer can exhibit appropriate optical characteristics.
  • the glass transition temperature of the resin having a negative intrinsic birefringence value is preferably 80° C. or higher, more preferably 90° C. or higher, further preferably 100° C. or higher, especially 110° C. or higher, particularly preferably 120° C. or higher. ..
  • Such a high glass transition temperature of the resin having a negative intrinsic birefringence value can reduce orientation relaxation of the resin having a negative intrinsic birefringence value.
  • the upper limit of the glass transition temperature of the resin having a negative intrinsic birefringence value is not particularly limited, but is usually 200° C. or lower.
  • the glass transition temperature can be measured by using a differential scanning calorimeter at a temperature rising rate of 10° C./min based on JIS K6911.
  • the second optically anisotropic layer including a layer made of a resin having a negative intrinsic birefringence value is combined with a layer containing a resin having a negative intrinsic birefringence value to obtain a resin having a negative intrinsic birefringence value. It is preferable to provide a protective layer capable of protecting the layer containing.
  • the protective layer is not particularly limited, but for example, a layer made of a resin having a positive intrinsic birefringence value can be used.
  • the in-plane retardation and the retardation in the thickness direction of the protective layer are preferably close to zero.
  • the glass transition temperature of the resin contained in the protective layer is set to the glass transition temperature of the resin having a negative intrinsic birefringence value. There is a method of lowering it.
  • the protective layer may be provided on only one side of the layer made of a resin having a negative intrinsic birefringence value, or may be provided on both sides.
  • one of the first optically anisotropic layer and the second optically anisotropic layer is composed of a ⁇ /2 plate, and the other is composed of a ⁇ /4 plate.
  • the ⁇ /2 plate is an optical member having an in-plane retardation of usually 200 nm or more and usually 300 nm or less at a measurement wavelength of 590 nm.
  • the ⁇ /4 plate is an optical member having an in-plane retardation of usually 75 nm or more and usually 154 nm or less at a measurement wavelength of 590 nm.
  • a broadband ⁇ /4 plate can be realized by combining the ⁇ /2 plate and the ⁇ /4 plate.
  • the circularly polarizing plate according to the present embodiment can exhibit a function of absorbing one of right circularly polarized light and left circularly polarized light and transmitting the remaining light in a wide wavelength range. Therefore, the circularly polarizing plate provided with the optically anisotropic laminate of such an aspect makes it possible to reduce reflection of light in a wide wavelength range in both the front direction and the tilt direction.
  • the optically anisotropic laminate of the present embodiment has a step 1 of stretching a first resin film containing a resin having a positive intrinsic birefringence value to obtain a first optically anisotropic layer, and a negative intrinsic birefringence value.
  • Step 1 is a step of stretching a first resin film containing a resin having a positive intrinsic birefringence value to obtain a first optically anisotropic layer.
  • the first resin film containing a resin having a positive intrinsic birefringence value used in step 1 can be produced by a melt molding method or a solution casting method, and the melt molding method is preferable. Further, among the melt molding methods, the extrusion molding method, the inflation molding method or the press molding method is preferable, and the extrusion molding method is particularly preferable.
  • the first resin film is obtained as a long resin film.
  • the first resin film is obtained as a long resin film.
  • the stretching method of the first resin film an appropriate method can be arbitrarily adopted depending on the optical characteristics to be expressed by stretching.
  • the stretching method of the first resin film is not particularly limited, but unidirectional stretching (uniaxial stretching) is preferable.
  • unidirectional stretching By unidirectionally stretching the first resin film, the uniaxiality of the layer containing the resin having a positive intrinsic birefringence value can be enhanced, and NZ1 can be brought close to 1.0.
  • Unidirectional stretching includes, for example, free-end uniaxial stretching and fixed-end uniaxial stretching.
  • the first resin film may be stretched once in one direction or two directions.
  • the stretching direction of the first resin film is not particularly limited. Stretching of the first resin film may include stretching in an oblique direction.
  • the first optically anisotropic layer as an obliquely stretched film can be obtained by a production method including stretching in an oblique direction.
  • the obliquely stretched film means a film produced by a production method including stretching in an oblique direction.
  • the obliquely stretched film develops a slow axis that is neither parallel nor perpendicular to the width direction. Therefore, in the first optically anisotropic layer as the obliquely stretched film, a slow axis forming a predetermined angle with respect to the width direction can be easily expressed.
  • the first optically anisotropic layer as the obliquely stretched film is laminated with the polarizing film having the transmission axis in the width direction and the second optically anisotropic layer by roll-to-roll to easily manufacture a circularly polarizing plate. it can.
  • the stretch ratio of the first resin film is preferably 1.1 times or more, more preferably 1.3 times or more, particularly preferably 1.5 times or more, preferably 4 times or less, more preferably 3 times or less, It is particularly preferably 2.5 times or less.
  • the stretch ratio of the first resin film is preferably 1.1 times or more, more preferably 1.3 times or more, particularly preferably 1.5 times or more, preferably 4 times or less, more preferably 3 times or less, It is particularly preferably 2.5 times or less.
  • the stretching temperature of the first resin film is preferably Tg 1 °C or higher, more preferably “Tg 1 +2 °C” or higher, particularly preferably “Tg 1 +5 °C” or higher, preferably “Tg 1 +40 °C” or lower, It is more preferably “Tg 1 +35°C” or lower, and particularly preferably "Tg 1 +30°C” or lower.
  • Tg 1 represents the glass transition temperature of the resin having a positive intrinsic birefringence value.
  • step 1 method for producing the first optically anisotropic layer
  • any step other than the steps described above may be further performed.
  • a trimming step of cutting out the first optically anisotropic layer into a desired shape may be performed. ..
  • a single-wafer first optically anisotropic layer having a desired shape is obtained.
  • a step of providing a protective layer on the first optically anisotropic layer may be performed.
  • Step 2 is a step of stretching a second resin film containing a resin having a negative intrinsic birefringence value to obtain a second optically anisotropic layer.
  • the second resin film containing a resin having a negative intrinsic birefringence value used in step 2 can be produced by a melt molding method or a solution casting method, and the melt molding method is preferable. Further, among the melt molding methods, the extrusion molding method, the inflation molding method or the press molding method is preferable, and the extrusion molding method is particularly preferable.
  • the second resin film is, for example, a multilayer film including a layer made of a resin having a negative intrinsic birefringence value and a protective layer, coextrusion T-die method, coextrusion inflation method, coextrusion lamination method, or other coextrusion method.
  • a method such as a molding method; a film lamination method such as dry lamination; a coating molding method in which a certain layer is coated with a resin solution forming the other layer can be used.
  • the coextrusion molding method is preferable from the viewpoint of good production efficiency and preventing volatile components such as a solvent from remaining in the second optically anisotropic layer.
  • the coextrusion molding methods the coextrusion T-die method is preferable.
  • the co-extrusion T-die method includes a feed block method and a multi-manifold method, but the multi-manifold method is more preferable in that the variation in layer thickness can be reduced.
  • the second resin film is obtained as a long resin film.
  • some or all of the steps can be performed in-line when the second optically anisotropic layer is manufactured, so that the manufacturing is simple and easy. It can be done efficiently.
  • bidirectional stretching includes, for example, sequential biaxial stretching and simultaneous biaxial stretching.
  • the stretching direction of the second resin film is not particularly limited. Stretching of the second resin film preferably includes stretching in an oblique direction.
  • the second optically anisotropic layer as an obliquely stretched film can be obtained by a production method including stretching in an oblique direction. Usually, the obliquely stretched film develops a slow axis that is neither parallel nor perpendicular to the width direction. Therefore, in the second optically anisotropic layer as the obliquely stretched film, a slow axis forming a predetermined angle with respect to the width direction can be easily expressed.
  • the second optically anisotropic layer as the obliquely stretched film is laminated with the polarizing film having the transmission axis in the width direction and the first optically anisotropic layer by roll-to-roll to easily manufacture the circularly polarizing plate. it can.
  • the draw ratio of the second resin film is preferably 1.1 times or more, more preferably 1.2 times or more, particularly preferably 1.3 times or more, preferably 4 times or less, more preferably 3 times or less, It is particularly preferably 2.5 times or less.
  • the draw ratio of the second resin film is preferably 1.1 times or more, more preferably 1.2 times or more, particularly preferably 1.3 times or more, preferably 4 times or less, more preferably 3 times or less, It is particularly preferably 2.5 times or less.
  • the stretching temperature of the second resin film is preferably Tg 2 °C or higher, more preferably “Tg 2 +2 °C” or higher, particularly preferably “Tg 2 +5 °C” or higher, preferably “Tg 2 +40 °C” or lower, It is more preferably “Tg 2 +35°C” or lower, and particularly preferably "Tg 2 +30°C” or lower.
  • Tg 2 represents the glass transition temperature of a resin having a negative intrinsic birefringence value.
  • Step 2 may be performed at the same time as step 1, or may be performed before step 1. Further, in the step 2 (method for producing the second optically anisotropic layer), any step may be further performed in addition to the steps described above. For example, the same steps as the arbitrary steps exemplified in Step 1 (method for producing first optically anisotropic layer) may be performed.
  • Step 3 is a step of stacking the first optically anisotropic layer and the second optically anisotropic layer.
  • the first optically anisotropic layer and the second optically anisotropic layer are formed by the slow axis of the first optically anisotropic layer and the slow axis of the second optically anisotropic layer. Stack so that the angle is 85° to 95°. That is, the slow axis of the first optically anisotropic layer and the slow axis of the second optically anisotropic layer are stacked so as to be orthogonal to each other.
  • the angle formed by the slow axis of the first optically anisotropic layer and the slow axis of the second optically anisotropic layer is preferably 90°, for example ⁇ 5°, ⁇ 3°, ⁇ 2° or An error within a range of ⁇ 1° may be included. Therefore, the angle formed by the slow axis of the first optically anisotropic layer and the slow axis of the second optically anisotropic layer is, for example, 85° to 95°, 87° to 93°, 88° to 92°. , Or 89° to 91°.
  • An optical anisotropic laminate can be manufactured by stacking the first optical anisotropic layer and the second optical anisotropic layer and then bonding the two layers together.
  • a suitable adhesive may be used for bonding.
  • the adhesive for example, an adhesive similar to the adhesive that can be used for manufacturing the polarizing plate described below can be used. This laminating step is an optional step.
  • the circularly polarizing plate 500 of the present embodiment includes the linear polarizer 130 and the above-mentioned optically anisotropic laminate 100.
  • the circularly polarizing plate 500 of this embodiment By providing the circularly polarizing plate 500 of this embodiment on the display surface of the image display device, reflection of external light can be suppressed.
  • the circularly polarizing plate 500 of the present embodiment including the optically anisotropic layered product 100 of the present embodiment when the display surface is viewed from the tilt direction, reflection of external light is suppressed and coloring is effectively performed. Can be suppressed.
  • the circularly polarizing plate 500 of the present embodiment includes a linear polarizer 130, a first optical anisotropic layer 110, and the second optical anisotropic layer 120 in this order.
  • 132 is an axis obtained by projecting the transmission axis 131 of the linear polarizer 130 onto the first optical anisotropic layer 110
  • 133 is the transmission axis 131 of the linear polarizer 130 to the second optical anisotropic layer 120.
  • the angle ⁇ A1 is an angle formed by the slow axis 111 of the first optically anisotropic layer 110 clockwise with respect to the transmission axis 131 of the linear polarizer 130.
  • the angle ⁇ B1 is an angle formed by the slow axis 121 of the second optically anisotropic layer 120 clockwise with respect to the transmission axis 131 of the linear polarizer 130.
  • the angle ⁇ A1 formed by the transmission axis 131 of the linear polarizer 130 and the slow axis 111 of the first optically anisotropic layer 110 is preferably close to 45°.
  • the angle ⁇ A1 is specifically preferably 45° ⁇ 5° (ie, preferably 40°-50°), more preferably 45° ⁇ 4° (ie, more preferably 41°-49°), particularly It is preferably 45° ⁇ 3° (that is, particularly preferably 42° to 48°).
  • the slow axis 111 of the first optical anisotropic layer 110 makes the angle ⁇ A1 clockwise with respect to the transmission axis 131 of the linear polarizer 130, the transmission of the linear polarizer 130 is shown.
  • the direction in which the slow axis 111 of the first optical anisotropic layer 110 forms the angle ⁇ A1 with respect to the axis 131 may be clockwise or counterclockwise. Furthermore, the direction in which the slow axis 121 of the second optical anisotropic layer 120 forms the angle ⁇ B1 with respect to the transmission axis 131 of the linear polarizer 130 may be clockwise or counterclockwise.
  • the angle between the absorption axis (not shown) of the linear polarizer 130 and the slow axis 111 of the first optically anisotropic layer 110 is preferably close to 45°.
  • the angle between the absorption axis of the linear polarizer 130 and the slow axis 111 of the first optical anisotropic layer 110 is specifically 45° ⁇ 5° (that is, preferably 40°-50°). More preferably 45° ⁇ 4° (ie, more preferably 41° to 49°), particularly preferably 45° ⁇ 3° (ie, particularly preferably 42° to 48°).
  • the direction in which the slow axis 111 of the first optical anisotropic layer 110 forms the angle with respect to the absorption axis of the linear polarizer 130 may be clockwise or counterclockwise.
  • any linear polarizer can be used as the linear polarizer 130.
  • the linear polarizer a film obtained by adsorbing iodine or a dichroic dye on a polyvinyl alcohol film and then unidirectionally stretching it in a boric acid bath; A film obtained by adsorbing and stretching, and further modifying a part of polyvinyl alcohol units in the molecular chain into polyvinylene units.
  • the linear polarizer include a polarizer having a function of separating polarized light into reflected light and transmitted light, such as a grid polarizer and a multilayer polarizer.
  • the linear polarizer 130 is preferably a polarizer containing polyvinyl alcohol.
  • the degree of polarization of the linear polarizer 130 is not particularly limited, but is preferably 98% or more, more preferably 99% or more.
  • the thickness of the linear polarizer 130 is preferably 5 ⁇ m to 80 ⁇ m.
  • the circularly polarizing plate may further include an adhesive layer for bonding the linear polarizer and the optically anisotropic laminate.
  • an adhesive layer made of an adhesive adhesive may be used, or a layer formed by curing a curable adhesive may be used.
  • a thermosetting adhesive may be used as the curable adhesive, but a photocurable adhesive is preferably used.
  • the photocurable adhesive one containing a polymer or a reactive monomer can be used. Further, the adhesive may contain a solvent, a photopolymerization initiator, other additives, etc., if necessary.
  • Photo-curable adhesives are adhesives that can be cured by irradiation with light such as visible light, ultraviolet rays, and infrared rays. Among them, an adhesive that can be cured by ultraviolet rays is preferable because it is easy to operate.
  • the thickness of the adhesive layer is preferably 0.5 ⁇ m or more, more preferably 1 ⁇ m or more, preferably 30 ⁇ m or less, more preferably 20 ⁇ m or less, still more preferably 10 ⁇ m or less.
  • the above-mentioned circularly polarizing plate may further include an optional layer.
  • the optional layer include a polarizer protective film layer, a hard coat layer such as an impact-resistant polymethacrylate resin layer, a mat layer that improves the slipperiness of the film, a reflection suppressing layer, an antifouling layer, and an antistatic layer. Can be mentioned. These optional layers may be provided in only one layer or in two or more layers.
  • the circularly polarizing plate of this embodiment can be used for an image display device.
  • the image display device of the present embodiment includes the circularly polarizing plate of the present embodiment and an organic electroluminescence element (hereinafter, also referred to as “organic EL element” as appropriate).
  • This image display device usually comprises a linear polarizer, an optically anisotropic laminate and an organic EL element in this order.
  • the image display device may include a linear polarizer, a first optical anisotropic layer, a second optical anisotropic layer and an organic EL element in this order.
  • the organic EL element includes a transparent electrode layer, a light emitting layer, and an electrode layer in this order, and the light emitting layer may generate light when a voltage is applied from the transparent electrode layer and the electrode layer.
  • materials forming the organic light emitting layer include polyparaphenylene vinylene-based materials, polyfluorene-based materials, and polyvinylcarbazole-based materials.
  • the light emitting layer may have a laminated body of a plurality of layers having different emission colors or a mixed layer in which a certain dye layer is doped with different dyes.
  • the organic EL element may include functional layers such as a hole injection layer, a hole transport layer, an electron injection layer, an electron transport layer, an equipotential surface forming layer, and a charge generation layer.
  • the above image display device can suppress reflection of external light on the display surface. Specifically, the light incident from the outside of the device becomes circularly polarized light because only part of the linearly polarized light passes through the linear polarizer and then it passes through the optically anisotropic laminate. The circularly polarized light is reflected by a constituent element (a reflective electrode (not shown) in the organic EL element, etc.) that reflects light in the display device, and again passes through the optically anisotropic laminated body to make incident linearly polarized light.
  • the linearly polarized light has a vibration direction orthogonal to the vibration direction of, and does not pass through the linear polarizer.
  • the direction of vibration of linearly polarized light means the direction of vibration of the electric field of linearly polarized light. Thereby, the function of suppressing reflection is achieved.
  • the image display device since the optically anisotropic laminate has predetermined optical characteristics, the reflection suppressing function can be exerted not only in the front direction of the display surface but also in the tilt direction. And thereby, the coloring of the display surface due to the reflected light can be suppressed. Therefore, the image display device can effectively suppress reflection of external light and suppress coloring in both the front direction and the tilt direction of the display surface.
  • the degree of coloring can be evaluated by the color difference ⁇ E * ab between the chromaticity measured by observing the display surface from the tilt direction and the chromaticity of the black display surface without reflection.
  • the chromaticity is obtained by measuring the spectrum of the light reflected on the display surface and multiplying the spectral sensitivity (color matching function) corresponding to the human eye from this spectrum to obtain the tristimulus values X, Y, and Z. It can be obtained by calculating the degree (a * , b * , L * ).
  • the color difference ⁇ E * ab is the chromaticity (a0 * , b0 * , L0 * ) when the display surface is not illuminated by external light and the chromaticity (a1 when illuminated by external light. * , b1 * , L1 * ) can be obtained from the following formula (X).
  • the coloring of the display surface due to the reflected light may differ depending on the azimuth angle in the viewing direction. Therefore, when observed from the tilt direction of the display surface, the measured chromaticity may differ depending on the azimuth angle of the observation direction, and thus the color difference ⁇ E * ab may also differ. Therefore, as described above, when evaluating the degree of coloring when observed from the tilt direction of the display surface, the evaluation of coloring is performed by the average value of the color difference ⁇ E * ab obtained by observing from a plurality of azimuth directions. It is preferable to carry out. Specifically, in 5 ° increments in azimuth, the azimuth angle phi (see FIG.
  • FIG. 2 is an exploded perspective view schematically showing the circularly polarizing plate 600 according to the second embodiment.
  • the optically anisotropic laminate 200 of the present embodiment is provided in the same manner as in the first embodiment except that the arrangement of the second optically anisotropic layer 120 and the first optically anisotropic layer 110 is different from that of the first embodiment. Has been.
  • the same components as those in the first embodiment are designated by the same reference numerals, and the duplicated description will be omitted.
  • the circularly polarizing plate 600 of the present embodiment includes a linear polarizer 130 and the optically anisotropic laminated body 200 of the present embodiment. As shown in FIG. 2, the circularly polarizing plate 600 of the present embodiment includes a linear polarizer 130, the second optically anisotropic layer 120, and the first optically anisotropic layer 110 in this order.
  • 132 is an axis obtained by projecting the transmission axis of the linear polarizer onto the first optically anisotropic layer 110
  • 133 is an axis obtained by projecting the transmission axis of the linear polarizer onto the second optically anisotropic layer 120.
  • the angle ⁇ A2 is an angle formed by the slow axis 111 of the first optically anisotropic layer 110 clockwise with respect to the transmission axis 131 of the linear polarizer 130.
  • the angle ⁇ B2 is an angle formed by the slow axis 121 of the second optically anisotropic layer 120 clockwise with respect to the transmission axis 131 of the linear polarizer 130.
  • the angles ⁇ A2 and ⁇ B2 are preferably in the same ranges as the angles ⁇ A1 and ⁇ B1 described in the first embodiment, respectively.
  • the circularly polarizing plate of this embodiment can be used in an image display device.
  • An image display device usually includes a linear polarizer, an optically anisotropic laminate and an organic EL element in this order. Therefore, the image display device including the circularly polarizing plate of the present embodiment may include the linear polarizer, the second optical anisotropic layer, the first optical anisotropic layer, and the organic EL element in this order.
  • the optically anisotropic laminate 200 has optical characteristics satisfying the above formulas (1) to (4), and has the slow axis 111 of the first optically anisotropic layer 110 and the first axis. 2
  • the angle formed by the slow axis 121 of the optically anisotropic layer 120 is 85° to 95°. Therefore, by providing the image display device with the circularly polarizing plate 600 obtained by combining such an optically anisotropic laminate 200 with the linear polarizer 130, when the display surface of the image display device is viewed from the tilt direction. Coloring can be effectively suppressed by suppressing reflection of external light.
  • the in-plane retardations Re1(450), Re1(550), Re1(590), Re1(650), and wavelength 590 nm at wavelengths of 450 nm, 550 nm, 590 nm, and 650 nm are used.
  • the retardation Rth1 (590) in the thickness direction and the slow axis direction were measured.
  • the in-plane retardations Re2(450), Re2(550), Re2(590), Re2(650), and wavelength at wavelengths of 450 nm, 550 nm, 590 nm, and 650 nm are used.
  • the retardation Rth2 (590) in the thickness direction at 590 nm and the slow axis direction were measured.
  • Re1(450)/Re1(550) and Re1(450)/Re1(550) were calculated using the obtained in-plane retardation.
  • the NZ coefficient (NZ1, NZ2) was calculated from the obtained ratio of the in-plane retardation and the thickness direction retardation.
  • the in-plane retardations Re(450), Re(550), and Re(650) at the wavelengths of 450 nm, 550 nm, and 650 nm of the optically anisotropic laminate are the first optically anisotropic layer and the second optically anisotropic layer. It was calculated from the optical characteristic values of the optically anisotropic layer.
  • a circularly polarizing plate having a second optically anisotropic layer, a first optically anisotropic layer and a polarizing film on the reflecting surface of a mirror having a planar reflecting surface in this order from the reflecting surface side. was set up.
  • the first optically anisotropic layer and the second optically anisotropic layer those used in each Example and Comparative Example were set.
  • the polarizing film a generally used polarizing plate having a polarization degree of 99.99% was set.
  • the mirror an ideal mirror capable of specularly reflecting the incident light with a reflectance of 100% was set.
  • FIG. 3 is a perspective view schematically showing a state of the evaluation model set when the color space coordinates are calculated in the simulations of the example and the comparative example.
  • the calculation of the color difference ⁇ E * ab was performed in the observation direction 20 in which the polar angle ⁇ with respect to the reflecting surface 10 was 0°, and the color difference ⁇ E * ab in the front direction was obtained.
  • the polar angle ⁇ represents an angle formed with respect to the normal direction 11 of the reflecting surface 10.
  • the calculation of the color difference ⁇ E * ab was performed in the observation direction 20 in which the polar angle ⁇ with respect to the reflecting surface 10 was 60°.
  • the azimuth angle ⁇ represents an angle formed by a direction parallel to the reflecting surface 10 with respect to a certain reference direction 12 parallel to the reflecting surface 10.
  • Example and Comparative Example A large number of people conducted the above observations, and calculated the total points given for each Example and Comparative Example. Examples and comparative examples were arranged in the order of the above total points, and the range of the total points was divided into 5 equal parts and evaluated in the order of A, B, C, D and E from the upper group.
  • the stretching treatment in the width direction was performed by stretching the first optically anisotropic layer of Example 1 in Table 1 below at a stretching temperature of 120° C. to 150° C. and a stretching ratio of 2.0 times to 5.0 times. It was set so that a ⁇ /2 plate having the physical property values (Re1, Rth1) described in the column could be obtained. In this way, a long ⁇ /2 plate A was obtained. The film thickness of this ⁇ /2 plate A was 50 ⁇ m. The in-plane retardation and the thickness direction retardation of this ⁇ /2 plate A were measured by the above-described methods.
  • the measured Re1 (590) was 280 nm
  • Rth1 (590) was 168 nm
  • nx1 was 1.5339
  • ny1 was 1.5283
  • nz1 was 1.5278. From this result, the relationship between nx1, ny1 and nz1 was nx1>ny1>nz1, which satisfied the formula (1).
  • the stretching treatment in the width direction was performed by stretching the first optically anisotropic layer of Comparative Example 2 in Table 2 below at a stretching temperature of 120° C. to 150° C. and a stretching ratio of 2.0 times to 5.0 times. It was set so that a ⁇ /2 plate having the physical property values (Re1, Rth1) described in the column could be obtained. In this way, a long ⁇ /2 plate B was obtained. The film thickness of this ⁇ /2 plate B was 50 ⁇ m. The in-plane retardation and the thickness direction retardation of the ⁇ /2 plate B were measured by the above-described methods.
  • the measured Re1 (590) was 280 nm, Rth1 (590) was 190 nm, nx1 was 1.5341, ny1 was 1.5285, and nz1 was 1.5275. From this result, the relationship between nx1, ny1 and nz1 was nx1>ny1>nz1, which satisfied the formula (1).
  • the prepared styrene-maleic acid copolymer resin, acrylic resin and adhesive are co-extruded to form an acrylic resin layer, an adhesive layer, a styrene-maleic acid copolymer resin layer, an adhesive layer and an acrylic resin layer.
  • a long second resin film having layers in this order was obtained.
  • a long ⁇ /4 plate is obtained by subjecting the second resin film produced in (3-1-1) to a stretching treatment (bidirectional stretching treatment) in the width direction and the longitudinal direction of the second resin film.
  • a stretching treatment bidirectional stretching treatment
  • the conditions for the above-mentioned bidirectional stretching treatment are ⁇ /4 plates having physical properties (Re2, Rth2) described in the columns of the second optically anisotropic layer in Examples 1 to 4 and Comparative Example 3 in Table 1 below. I was set to be able to.
  • the stretching conditions in the width direction of the film are set such that the stretching temperature is 110° C. to 140° C. and the stretching ratio is 1.5 to 4.0.
  • the conditions for the stretching treatment in the longitudinal direction of the film were set at a stretching temperature of 110° C. to 140° C. and a stretching ratio of 1.5 to 4.0.
  • ⁇ /4 plates A to F were obtained.
  • the thickness of each of the obtained ⁇ /4 plates A to F was 40 ⁇ m.
  • the in-plane retardation and the retardation in the thickness direction of each of the obtained ⁇ /4 plates A to E were measured by the above method. No retardation was developed in the acrylic resin layer and the adhesive layer of each ⁇ /4 plate.
  • the measurement results of the ⁇ /4 plate A were Re2(590) of 147 nm, Rth2(590) of -132 nm, nx2 of 1.5582, ny2 of 1.5545, and nz2 of 1.5597.
  • the measurement results of the ⁇ /4 plate B were Re2(590) of 147 nm, Rth2(590) of -162 nm, nx2 of 1.5580, ny2 of 1.5543, and nz2 of 1.5602.
  • the measurement results of the ⁇ /4 plate C were Re2(590) of 147 nm, Rth2(590) of -191 nm, nx2 of 1.5577, ny2 of 1.5540, and nz2 of 1.5607.
  • the measurement results of the ⁇ /4 plate D were Re2(590) of 147 nm, Rth2(590) of ⁇ 220 nm, nx2 of 1.5575, ny2 of 1.5538, and nz2 of 1.5611.
  • the measurement results of the ⁇ /4 plate E were Re2(590) of 147 nm, Rth2(590) of -162 nm, nx2 of 1.5580, ny2 of 1.5543, and nz2 of 1.5602. From these results, in all of the ⁇ /4 plates A to E, the relationship of nx2, ny2, and nz2 was nz2>nx2>ny2, which satisfied the expression (2).
  • the in-plane retardation and the retardation in the thickness direction of the ⁇ /4 plate F were measured by the above method. No retardation was developed in the obtained ⁇ /4 plate acrylic resin layer and adhesive layer.
  • the measured Re2 (590) was 147 nm
  • Rth2 (590) was -88 nm
  • nx2 was 1.5586,
  • ny2 was 1.5549
  • nz2 was 1.5589. From this result, the relationship between nx2, ny2, and nz2 was nz2>nx2>ny2.
  • Example 1 A long polarizing film, a long .lamda./2 plate A and a long .lamda./4 plate A are respectively cut out to obtain a sheet of polarizing film, a sheet of .lamda./2 plate A and a sheet of .lamda./4 plate. I got A.
  • the sheet-shaped polarizing film, the sheet-shaped ⁇ /2 plate A and the sheet-shaped ⁇ /4 plate A are attached to each other using an adhesive (“CS9621” manufactured by Nitto Denko Corporation) to obtain a polarizing film and an adhesive layer.
  • a ⁇ /2 plate A (first optically anisotropic layer), an adhesive layer and a ⁇ /4 plate A (second optically anisotropic layer) were obtained in this order to obtain a circularly polarizing plate.
  • This circularly polarizing plate is a mode corresponding to the first embodiment (see FIG. 1).
  • the ⁇ /2 plate A is the first optically anisotropic layer and the ⁇ /4 plate A is the second optically anisotropic layer.
  • the above-mentioned bonding is such that when viewed from the polarizing film side, the angle ⁇ A1 formed by the slow axis of the ⁇ /2 plate A clockwise with respect to the transmission axis of the polarizing film is 45°, and the transmission axis of the polarizing film is Then, the angle ⁇ B1 formed by the slow axis of the ⁇ /4 plate A in the clockwise direction was set to 135°.
  • the obtained circularly polarizing plate was evaluated by the method described above. Re(450), Re(550) and Re(650) of the optically anisotropic layered product included in the circularly polarizing plate of this example satisfied the following formula (3).
  • Example 2 The same operation as in Example 1 was performed except that the long ⁇ /4 plate A was changed to the long ⁇ /4 plate B, and the polarizing film, the adhesive layer, the ⁇ /2 plate A, the adhesive layer and ⁇ / A circularly polarizing plate having 4 plates B in this order was obtained.
  • the ⁇ /2 plate A is the first optically anisotropic layer
  • the ⁇ /4 plate B is the second optically anisotropic layer.
  • the obtained circularly polarizing plate was evaluated by the above method.
  • Re(450), Re(550) and Re(650) of the optically anisotropic laminate contained in this circularly polarizing plate satisfied the above formula (3).
  • the first optically anisotropic layer satisfies the above formula (1)
  • the second optically anisotropic layer satisfies the above formula (2)
  • the sum of NZ1 and NZ2 is 0. It was 0.5.
  • Example 3 The same operation as in Example 1 was performed except that the long ⁇ /4 plate A was changed to the long ⁇ /4 plate C, and the polarizing film, the adhesive layer, the ⁇ /2 plate A, the adhesive layer and ⁇ / A circularly polarizing plate having 4 plates C in this order was obtained.
  • the ⁇ /2 plate A is the first optically anisotropic layer
  • the ⁇ /4 plate C is the second optically anisotropic layer.
  • the obtained circularly polarizing plate was evaluated by the above method.
  • Re(450), Re(550) and Re(650) of the optically anisotropic laminate contained in this circularly polarizing plate satisfied the above formula (3).
  • the first optically anisotropic layer satisfies the above formula (1)
  • the second optically anisotropic layer satisfies the above formula (2)
  • the sum of NZ1 and NZ2 is 0. It was .3.
  • Example 4 The same operation as in Example 1 was performed except that the long ⁇ /4 plate A was changed to the long ⁇ /4 plate D, and the polarizing film, the adhesive layer, the ⁇ /2 plate A, the adhesive layer and ⁇ / A circularly polarizing plate having 4 plates D in this order was obtained.
  • the ⁇ /2 plate A is the first optically anisotropic layer
  • the ⁇ /4 plate D is the second optically anisotropic layer.
  • the obtained circularly polarizing plate was evaluated by the above method. Re(450), Re(550) and Re(650) of the optically anisotropic laminate contained in this circularly polarizing plate satisfied the above formula (3).
  • the first optically anisotropic layer satisfies the above formula (1)
  • the second optically anisotropic layer satisfies the above formula (2)
  • the sum of NZ1 and NZ2 is 0. It was 1.
  • Example 1 The same operation as in Example 1 was performed except that the long ⁇ /4 plate A was changed to the long ⁇ /4 plate F, and the polarizing film, the adhesive layer, the ⁇ /2 plate A, the adhesive layer and ⁇ / A circularly polarizing plate having 4 plates F in this order was obtained.
  • the ⁇ /2 plate A is the first optically anisotropic layer
  • the ⁇ /4 plate F is the second optically anisotropic layer.
  • the obtained circularly polarizing plate was evaluated by the above method.
  • the Re(450), Re(550) and Re(650) of the optically anisotropic laminate contained in this circularly polarizing plate are Re(450) ⁇ Re(550) ⁇ Re(650) and are represented by the above formula ( 3) was satisfied.
  • the first optically anisotropic layer satisfies the above formula (1)
  • the second optically anisotropic layer satisfies the above formula (2)
  • the sum of NZ1 and NZ2 is 1.0. Met.
  • Example 2 The same operation as in Example 1 was performed except that the following points were changed to obtain a circularly polarizing plate having a polarizing film, an adhesive layer, a ⁇ /2 plate B, an adhesive layer and a ⁇ /4 plate F in this order. ..
  • the ⁇ /2 plate B is the first optically anisotropic layer
  • the ⁇ /4 plate F is the second optically anisotropic layer.
  • the obtained circularly polarizing plate was evaluated by the above method. Further, Re(450), Re(550) and Re(650) of the optically anisotropic laminate contained in this circularly polarizing plate are Re(450) ⁇ Re(550) ⁇ Re(650), It satisfied the formula (3).
  • the first optically anisotropic layer satisfies the above formula (1)
  • the second optically anisotropic layer satisfies the above formula (2)
  • the sum of NZ1 and NZ2 is 1.08.
  • Met. (change point) The long ⁇ /2 plate A was changed to the long ⁇ /2 plate B.
  • the long ⁇ /4 plate A was changed to the long ⁇ /4 plate F.
  • the layers are stuck together such that when viewed from the polarizing film side, the angle ⁇ A1 formed by the slow axis of the ⁇ /2 plate B in the clockwise direction with respect to the transmission axis of the polarizing film is 22.5°, and the transmission of the polarizing film.
  • the angle ⁇ B1 formed by the slow axis of the ⁇ /4 plate F clockwise with respect to the axis was set to 90°.
  • Example 3 The same operation as in Example 1 was performed except that the following points were changed to obtain a circularly polarizing plate including a polarizing film, an adhesive layer, a ⁇ /2 plate B, an adhesive layer and a ⁇ /4 plate E in this order. ..
  • the ⁇ /2 plate B is the first optically anisotropic layer
  • the ⁇ /4 plate E is the second optically anisotropic layer.
  • the obtained circularly polarizing plate was evaluated by the above method. Further, Re(450), Re(550) and Re(650) of the optically anisotropic laminate contained in this circularly polarizing plate are Re(450) ⁇ Re(550) ⁇ Re(650), It satisfied the formula (3).
  • the first optically anisotropic layer satisfies the above formula (1)
  • the second optically anisotropic layer satisfies the above formula (2)
  • the sum of NZ1 and NZ2 is 0. It was 0.58.
  • the long ⁇ /2 plate A was changed to the long ⁇ /2 plate B.
  • the long ⁇ /4 plate A was changed to the long ⁇ /4 plate E.
  • the layers are stuck together such that when viewed from the polarizing film side, the angle ⁇ A1 formed by the slow axis of the ⁇ /2 plate B in the clockwise direction with respect to the transmission axis of the polarizing film is 22.5°, and the transmission of the polarizing film.
  • the angle ⁇ B1 formed by the slow axis of the ⁇ /4 plate F clockwise with respect to the axis was set to 90°.
  • Comparative Example 4 The circularly polarizing plate of Comparative Example 4 was manufactured by the following method (the same method as Example 1 in JP 2010-266723 A).
  • C4-1) Production of Film C1 (a film containing a resin having a positive intrinsic birefringence value)
  • a first unstretched film made of a norbornene-based polymer (“ZEONOR1420” manufactured by Nippon Zeon Co., Ltd., glass transition temperature: 136° C.)
  • the roll-wound body was obtained by melt extrusion molding. Then, the roll-shaped body of the first unstretched film was stretched using a tenter stretching machine (see FIG.
  • the film was roll-formed into a roll C1 by obliquely stretching the film C1 in a direction of 45° with respect to the width direction.
  • the film C1 thus obtained had an Nz coefficient (NZ1) of 1.1, a Re1 (590) of 66 nm, an angle formed by the slow axis with respect to the width direction of 44.8°, and a thickness of 120 ⁇ m. It was
  • the unstretched laminate was pulled out from this roll-shaped body and stretched at a stretching temperature of 138° C., a stretching ratio of 1.7 times, and a stretching speed of 8 mm/min using the same tenter stretching machine as in (C4-1).
  • a roll wound body of the film C2 was obtained.
  • the obtained film C2 has an Nz coefficient (NZ2) of ⁇ 0.1, a Re2 (590) of 66 nm, an angle formed by the slow axis with respect to the width direction of ⁇ 45.2°, and a thickness of 130 ⁇ m. Met.
  • (C4-4) Production of Circularly Polarizing Plate The optically anisotropic laminate C3 obtained in (C4-3) and a polarizing film (manufactured by Sanritz Co., HLC2-5618S, thickness 180 ⁇ m) were combined with each other by a laminating device (special (See FIG. 4 of Kai 2010-266723) was laminated by a roll-to-roll method to produce a circularly polarizing film, which was cut into a predetermined size to obtain a circularly polarizing plate.
  • a laminating device special (See FIG. 4 of Kai 2010-266723) was laminated by a roll-to-roll method to produce a circularly polarizing film, which was cut into a predetermined size to obtain a circularly polarizing plate.
  • the obtained circularly polarizing plate was evaluated by the above-described evaluation method in the same manner as in Example 1.
  • the relationship of Re(450), Re(550) and Re(650) of the optically anisotropic laminate contained in the circularly polarizing plate of this example is Re(450)>Re(550)>Re(650). Yes, the formula (3) was not satisfied.
  • the first optically anisotropic layer satisfies the following formula (1)
  • the second optically anisotropic layer satisfies the following formula (2)
  • the sum of NZ1 and NZ2 is 1. It was 0.0.
  • Rth1 Phase difference in the thickness direction of the ⁇ /2 plate (first optically anisotropic layer) at a measurement wavelength of 590 nm.
  • ⁇ A1 An angle formed by the slow axis of the ⁇ /2 plate (first optically anisotropic layer) in the clockwise direction with respect to the transmission axis of the polarizing film when viewed from the polarizing film side.
  • NZ1 NZ coefficient of ⁇ /2 plate (first optical anisotropic layer).
  • Re2 In-plane retardation of a ⁇ /4 plate (second optically anisotropic layer) at a measurement wavelength of 590 nm.
  • Re2 (550) In-plane retardation of a ⁇ /4 plate (second optically anisotropic layer) at a measurement wavelength of 550 nm.
  • Re2 (450) In-plane retardation of a ⁇ /4 plate (second optically anisotropic layer) at a measurement wavelength of 4590 nm.
  • Rth2 (590) Phase difference in the thickness direction of the ⁇ /4 plate (second optically anisotropic layer) at a measurement wavelength of 590 nm.
  • ⁇ B1 An angle formed by the slow axis of the ⁇ /4 plate (second optically anisotropic layer) in the clockwise direction with respect to the transmission axis of the polarizing film as viewed from the polarizing film side.
  • NZ2 NZ coefficient of ⁇ /4 plate (second optically anisotropic layer).
  • Angle formed by the slow axis An angle formed by the slow axis of the first optically anisotropic layer and the slow axis of the second optically anisotropic layer.
  • the image display devices including the optically anisotropic laminates of Examples 1 to 4 were compared with the image display devices including the optically anisotropic laminates of Comparative Examples 1 to 4, It can be seen that the coloring of the display surface when viewed from the front direction is suppressed equally, and the coloring of the display surface when viewed from the tilt direction is suppressed. From the above results, according to Examples 1 to 4 including the optically anisotropic laminate of the present invention, it is possible to realize the image display device in which the coloring of the display surface when viewed from the front direction and the tilt direction is suppressed.
  • the angle ⁇ A1 formed by the slow axis of the ⁇ /2 plate (first optically anisotropic layer) in the clockwise direction with respect to the transmission axis of the linear polarizer (polarizing film) was Although an optically anisotropic laminate of 45° is shown, the present invention is not limited to this. It may be an optically anisotropic laminate having an angle of 45° between the absorption axis of the linear polarizer and the slow axis of the first optically anisotropic layer.

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Abstract

This optically anisotropic laminate includes a first optically anisotropic layer and a second optically anisotropic layer, wherein the first optically anisotropic layer satisfies the following expression (1), the second optically anisotropic layer satisfies the following expression (2), the optically anisotropic laminate satisfies the following expression (3), an NZ factor NZ1 of the first optically anisotropic layer and an NZ factor NZ2 of the second optically anisotropic layer satisfy the following expression (4), and the angle formed by the slow axis of the first optically anisotropic layer and the slow axis of the second optically anisotropic layer is 90°.　nx1>ny1≥nz1 expression (1), nz2>nx2>ny2 expression (2), Re(450)<Re(550)<Re(650) expression (3), -0.3≤NZ1+NZ2≤0.8 expression (4)

Description

光学異方性積層体及びその製造方法、円偏光板、並びに画像表示装置Optically anisotropic laminate, method for producing the same, circularly polarizing plate, and image display device
　本発明は、光学異方性積層体及びその製造方法、円偏光板、並びに画像表示装置に関する。 The present invention relates to an optically anisotropic laminate, a method for manufacturing the same, a circularly polarizing plate, and an image display device.
　有機エレクトロルミネッセンス画像表示装置などの画像表示装置は、外光を反射することにより、画像表示の品質が低下する場合がある。以下、有機エレクトロルミネッセンスを「有機ＥＬ」ということがある。特に反射電極を備えた有機ＥＬ画像表示装置の場合、画像表示の品質低下が顕著である。このような反射を抑制するため、画像表示装置の表示面に、円偏光板が設けられることがある（例えば、特許文献１を参照）。 Image display devices such as organic electroluminescence image display devices may reduce the quality of image display by reflecting external light. Hereinafter, organic electroluminescence may be referred to as “organic EL”. Particularly in the case of an organic EL image display device provided with a reflective electrode, the quality of image display is significantly reduced. In order to suppress such reflection, a circularly polarizing plate may be provided on the display surface of the image display device (for example, see Patent Document 1).
　外光は、円偏光板によりある方向の円偏光に変換され、画像表示装置により反射される際にある方向とは逆方向の円偏光となる。逆方向の円偏光となった反射光は、円偏光板を透過しないため、反射が抑制される。 External light is converted into circularly polarized light in a certain direction by the circularly polarizing plate, and becomes circularly polarized light in the opposite direction when reflected by the image display device. Since the reflected light that has become circularly polarized light in the opposite direction does not pass through the circularly polarizing plate, reflection is suppressed.
国際公開第２０１６／０４７４６５号International Publication No. 2016/047475 特開２０１０-２６６７２３号公報JP, 2010-266723, A
　上記特許文献１には、円偏光板が、直線偏光子と、直線偏光子の吸収軸に対して所定の角度をなす方向に遅相軸を有するλ／２板と、直線偏光子の吸収軸に対して所定の角度をなす方向に遅相軸を有するλ／４板とを備え、λ／２板の波長分散とλ／４板の波長分散とが相違し、かつλ／４板のＮＺ係数が所定値であるとの構成を具備することにより、反射を効果的に抑制しうることが記載されている。
　しかしながら、画像表示装置の表示面に、かかる円偏光板を設けた場合であっても、表示面を傾斜方向から観察すると、表示面で反射した光が視認されることによって、表示面が色付いて見えることがあった。 In Patent Document 1, the circularly polarizing plate includes a linear polarizer, a λ/2 plate having a slow axis in a direction forming a predetermined angle with respect to the absorption axis of the linear polarizer, and an absorption axis of the linear polarizer. And a λ/4 plate having a slow axis in a direction forming a predetermined angle with respect to the λ/2 plate, the wavelength dispersion of the λ/2 plate and the wavelength dispersion of the λ/4 plate are different, and the NZ of the λ/4 plate is It is described that reflection can be effectively suppressed by providing a configuration in which the coefficient is a predetermined value.
However, even when such a circularly polarizing plate is provided on the display surface of the image display device, when the display surface is observed from the tilt direction, the light reflected by the display surface is visually recognized, and thus the display surface is colored. I could see it.
　また上記文献２には、円偏光板が、直線偏光子と、二枚の延伸フィルムを遅相軸を平行に積層して作製したλ／４板において、そのＮＺ係数を所定値とすることにより、反射を抑制しうることが記載されている。
　しかしながら、画像表示装置の表示面に、かかる円偏光板を設けた場合には、表示面を正面方向および傾斜方向から観察した場合に、反射抑制効果が不十分であり、表示面が色付いて見えることがあった。 Further, in Document 2 above, a circularly polarizing plate is a λ/4 plate produced by laminating a linear polarizer and two stretched films in parallel with their slow axes in parallel, and by setting the NZ coefficient to a predetermined value, It is described that reflection can be suppressed.
However, when such a circularly polarizing plate is provided on the display surface of the image display device, the reflection suppressing effect is insufficient when the display surface is observed from the front direction and the tilt direction, and the display surface looks colored. There was something.
　よって、依然として、傾斜方向から見た表示面の色付きが抑制された画像表示装置を実現できる、光学異方性積層体及びその製造方法；傾斜方向から見た表示面の色付きが抑制された画像表示装置を実現できる円偏光板；ならびに傾斜方向から見た表示面の色付きが抑制された画像表示装置が求められている。 Therefore, it is still possible to realize an image display device in which coloring of the display surface viewed from the tilt direction is realized, and a method of manufacturing the same; an image display in which coloring of the display surface viewed from the tilt direction is suppressed. There is a demand for a circularly polarizing plate that can realize the device; and an image display device in which coloring of the display surface when viewed from the tilt direction is suppressed.
　前記課題を解決するべく、発明者は鋭意検討した結果、所定の光学的条件を満たす第１光学異方性層及び所定の光学的条件を満たす第２光学異方性層を含む光学異方性層積層体であって、第１光学異方性層のＮＺ係数ＮＺ１と第２光学異方性層のＮＺ係数ＮＺ２との和が所定範囲であり、第１光学異方性層の遅相軸と第２光学異方性層の遅相軸とが直交する態様とすることによって、前記課題を解決できることを見出し、本発明を完成した。すなわち、本発明は、以下を提供する。 In order to solve the above-mentioned problems, as a result of intensive studies made by the inventor, the optical anisotropy including a first optical anisotropic layer satisfying a predetermined optical condition and a second optical anisotropic layer satisfying a predetermined optical condition. In the layered laminate, the sum of the NZ coefficient NZ1 of the first optically anisotropic layer and the NZ coefficient NZ2 of the second optically anisotropic layer is within a predetermined range, and the slow axis of the first optically anisotropic layer is The present invention has been completed by finding that the above problems can be solved by adopting a mode in which the slow axis of the second optically anisotropic layer is orthogonal to the above. That is, the present invention provides the following.
　［１］　第１光学異方性層及び第２光学異方性層を含む光学異方性積層体であって、
　前記第１光学異方性層が、下記式（１）を満たし、
　前記第２光学異方性層が、下記式（２）を満たし、
　前記光学異方性積層体が、下記式（３）を満たし、
　前記第１光学異方性層のＮＺ係数ＮＺ１及び前記第２光学異方性層のＮＺ係数ＮＺ２が下記式（４）を満たし、
　前記第１光学異方性層の遅相軸と前記第２光学異方性層の遅相軸とのなす角度が、８５°～９５°である、光学異方性積層体。
　ｎｘ１＞ｎｙ１≧ｎｚ１　　　　　　　　　　　　　式（１）
　ｎｚ２＞ｎｘ２＞ｎｙ２　　　　　　　　　　　　　式（２）
　Ｒｅ（４５０）＜Ｒｅ（５５０）＜Ｒｅ（６５０）　式（３）
　－０．３≦ＮＺ１＋ＮＺ２≦０．８　　　　　　　　式（４）
　但し、
　ｎｘ１は、前記第１光学異方性層の面内方向であって最大の屈折率を与える方向の屈折率を表し、ｎｙ１は、前記第１光学異方性層の面内方向であって、ｎｘ１を与える方向に直交する方向の屈折率を表し、ｎｚ１は、前記第１光学異方性層の厚み方向の屈折率を表し、
　ｎｘ２は、前記第２光学異方性層の面内方向であって最大の屈折率を与える方向の屈折率を表し、ｎｙ２は、前記第２光学異方性層の面内方向であって、ｎｘ２を与える方向に直交する方向の屈折率を表し、ｎｚ２は、前記第２光学異方性層の厚み方向の屈折率を表し、
　Ｒｅ（４５０）、Ｒｅ（５５０）、及びＲｅ（６５０）は、波長４５０ｎｍ、５５０ｎｍ、及び６５０ｎｍにおける前記光学異方性積層体の面内位相差をそれぞれ表す。
　［２］波長５５０ｎｍにおける前記第１光学異方性層の面内位相差Ｒｅ１（５５０）、
　波長４５０ｎｍにおける前記第１光学異方性層の面内位相差Ｒｅ１（４５０）、
　波長５５０ｎｍにおける前記第２光学異方性層の面内位相差Ｒｅ２（５５０）及び、
　波長４５０ｎｍにおける前記第２光学異方性層の面内位相差Ｒｅ２（４５０）が、下記式（５）および式（６）を満たす、［１］に記載の光学異方性積層体。
　Ｒｅ１（４５０）／Ｒｅ１（５５０）＜Ｒｅ２（４５０）／Ｒｅ２（５５０）　式（５）
　Ｒｅ１(５５０)＞Ｒｅ２(５５０)　　　式（６）
　［３］　前記Ｒｅ１（５５０）と前記Ｒｅ２（５５０）との差が、１００ｎｍ以上１８０ｎｍ以下である、［２］に記載の光学異方性積層体。
　［４］　前記第１光学異方性層が、第１樹脂フィルムの延伸フィルムであり、
　前記第１樹脂フィルムは、正の固有複屈折値を有する樹脂を含む、［１］～［３］のいずれか１項に記載の光学異方性積層体。
　［５］　前記第１光学異方性層が、液晶配向層を含む、［１］～［４］のいずれか１項に記載の光学異方性積層体。
　［６］　前記第２光学異方性層が、第２樹脂フィルムの延伸フィルムであり、
　前記第２樹脂フィルムは、負の固有複屈折値を有する樹脂を含む、［１］～［５］のいずれか１項に記載の光学異方性積層体。
　［７］　前記第２光学異方性層が、前記第２樹脂フィルムを二方向延伸した延伸フィルムであり、前記ＮＺ２が－２．０以上－０．２以下である、［６］に記載の光学異方性積層体。
　［８］　直線偏光子と、
　［１］～［７］のいずれか１項記載の光学異方性積層体と、を備える円偏光板。
　［９］　前記直線偏光子の吸収軸または前記直線偏光子の透過軸と、前記第１光学異方性層の遅相軸とのなす角が４０°～５０°である、［８］に記載の円偏光板。
　［１０］　前記直線偏光子、前記第１光学異方性層、及び前記第２光学異方性層をこの順で備えるか、または、
　前記直線偏光子、前記第２光学異方性層、及び前記第１光学異方性層をこの順で備える、［８］または［９］に記載の円偏光板。
　［１１］　［８］～［１０］のいずれか１項に記載の円偏光板と、有機エレクトロルミネッセンス素子と、を備える画像表示装置であって、
　前記直線偏光子と、前記光学異方性積層体と、前記有機エレクトロルミネッセンス素子と、をこの順に備える、画像表示装置。
　［１２］　［１］～［７］のいずれか１項に記載の光学異方性積層体の製造方法であって、
　正の固有複屈折値を有する樹脂を含む第１樹脂フィルムを延伸して第１光学異方性層を得る工程１と、
　負の固有複屈折値を有する樹脂を含む第２樹脂フィルムを延伸して第２光学異方性層を得る工程２と、
　前記第１光学異方性層と前記第２光学異方性層とを重ねる工程３と、を含み、
　前記工程１において、前記第１樹脂フィルムを、一方向延伸し、
　前記工程２において、前記第２樹脂フィルムを、二方向延伸し、
　前記工程３において、前記第１光学異方性層の遅相軸と、前記第２光学異方性の遅相軸とのなす角が８５°～９５°となるように重ねる、光学異方性積層体の製造方法。 [1] An optically anisotropic laminate including a first optically anisotropic layer and a second optically anisotropic layer,
The first optically anisotropic layer satisfies the following formula (1),
The second optically anisotropic layer satisfies the following formula (2),
The optically anisotropic laminate satisfies the following formula (3),
The NZ coefficient NZ1 of the first optically anisotropic layer and the NZ coefficient NZ2 of the second optically anisotropic layer satisfy the following formula (4),
An optically anisotropic laminate, wherein an angle formed by the slow axis of the first optically anisotropic layer and the slow axis of the second optically anisotropic layer is 85° to 95°.
nx1>ny1≧nz1 Formula (1)
nz2>nx2>ny2 Formula (2)
Re(450)<Re(550)<Re(650) Formula (3)
−0.3≦NZ1+NZ2≦0.8 Formula (4)
However,
nx1 represents the in-plane direction of the first optically anisotropic layer and represents the refractive index in the direction that gives the maximum refractive index, and ny1 represents the in-plane direction of the first optically anisotropic layer, nx1 represents the refractive index in the direction orthogonal to the direction, and nz1 represents the refractive index in the thickness direction of the first optical anisotropic layer,
nx2 represents an in-plane direction of the second optically anisotropic layer and represents a refractive index in a direction that gives the maximum refractive index, and ny2 represents an in-plane direction of the second optically anisotropic layer, nx2 represents the refractive index in the direction orthogonal to the direction, and nz2 represents the refractive index in the thickness direction of the second optically anisotropic layer,
Re(450), Re(550), and Re(650) represent the in-plane retardation of the optically anisotropic laminate at wavelengths of 450 nm, 550 nm, and 650 nm, respectively.
[2] In-plane retardation Re1 (550) of the first optically anisotropic layer at a wavelength of 550 nm,
An in-plane retardation Re1(450) of the first optically anisotropic layer at a wavelength of 450 nm,
An in-plane retardation Re2(550) of the second optically anisotropic layer at a wavelength of 550 nm, and
The optically anisotropic laminate according to [1], wherein the in-plane retardation Re2(450) of the second optically anisotropic layer at a wavelength of 450 nm satisfies the following formulas (5) and (6).
Re1(450)/Re1(550)<Re2(450)/Re2(550) Formula (5)
Re1(550)>Re2(550) Formula (6)
[3] The optically anisotropic laminate according to [2], wherein the difference between Re1 (550) and Re2 (550) is 100 nm or more and 180 nm or less.
[4] The first optically anisotropic layer is a stretched film of a first resin film,
The optically anisotropic laminate according to any one of [1] to [3], wherein the first resin film contains a resin having a positive intrinsic birefringence value.
[5] The optically anisotropic laminate according to any one of [1] to [4], wherein the first optically anisotropic layer includes a liquid crystal alignment layer.
[6] The second optically anisotropic layer is a stretched film of a second resin film,
The optically anisotropic laminate according to any one of [1] to [5], wherein the second resin film contains a resin having a negative intrinsic birefringence value.
[7] The second optically anisotropic layer is a stretched film obtained by stretching the second resin film in two directions, and the NZ2 is −2.0 or more and −0.2 or less. Optically anisotropic laminate.
[8] A linear polarizer,
A circularly polarizing plate comprising: the optically anisotropic laminate according to any one of [1] to [7].
[9] The angle between the absorption axis of the linear polarizer or the transmission axis of the linear polarizer and the slow axis of the first optically anisotropic layer is 40° to 50°. Circular polarizing plate.
[10] The linear polarizer, the first optically anisotropic layer, and the second optically anisotropic layer are provided in this order, or
The circularly polarizing plate according to [8] or [9], which includes the linear polarizer, the second optically anisotropic layer, and the first optically anisotropic layer in this order.
[11] An image display device comprising the circularly polarizing plate according to any one of [8] to [10] and an organic electroluminescence element,
An image display device comprising: the linear polarizer, the optically anisotropic laminate, and the organic electroluminescent element in this order.
[12] The method for producing an optically anisotropic laminate according to any one of [1] to [7],
Step 1 of stretching a first resin film containing a resin having a positive intrinsic birefringence value to obtain a first optically anisotropic layer,
Step 2 of stretching a second resin film containing a resin having a negative intrinsic birefringence value to obtain a second optically anisotropic layer,
A step 3 of stacking the first optically anisotropic layer and the second optically anisotropic layer,
In the step 1, the first resin film is unidirectionally stretched,
In the step 2, the second resin film is bidirectionally stretched,
In the step 3, the optical anisotropy is formed so that an angle formed by the slow axis of the first optical anisotropic layer and the slow axis of the second optical anisotropy is 85° to 95°. Method for manufacturing laminated body.
　本発明によれば、傾斜方向から見た表示面の色付きが抑制された画像表示装置を実現できる、光学異方性積層体及びその製造方法；傾斜方向から見た表示面の色付きが抑制された画像表示装置を実現できる円偏光板；ならびに、傾斜方向から見た表示面の色付きが抑制された画像表示装置を提供することができる。 ADVANTAGE OF THE INVENTION According to this invention, the image display apparatus which suppressed the coloring of the display surface seen from the inclination direction can be implement|achieved, and its manufacturing method; The coloring of the display surface seen from the inclination direction was suppressed. It is possible to provide a circularly polarizing plate that can realize an image display device; and an image display device in which coloring of the display surface when viewed from the tilt direction is suppressed.
図１は、実施形態１に係る円偏光板を模式的に示す分解斜視図である。FIG. 1 is an exploded perspective view schematically showing the circularly polarizing plate according to the first embodiment. 図２は、実施形態２に係る円偏光板を模式的に示す分解斜視図である。FIG. 2 is an exploded perspective view schematically showing the circularly polarizing plate according to the second embodiment. 図３は、実施例及び比較例でのシミュレーションにおいて、色度の計算を行う際に設定した評価モデルの様子を模式的に示す斜視図である。FIG. 3 is a perspective view schematically showing a state of the evaluation model set when the chromaticity is calculated in the simulations of the example and the comparative example.
　以下、本発明について実施形態及び例示物を示して詳細に説明する。ただし、本発明は以下に示す実施形態及び例示物に限定されるものではなく、本発明の請求の範囲及びその均等の範囲を逸脱しない範囲において任意に変更して実施しうる。 Hereinafter, the present invention will be described in detail by showing embodiments and exemplifications. However, the present invention is not limited to the embodiments and exemplifications shown below, and may be implemented by being arbitrarily modified within the scope of the claims of the present invention and the scope of equivalents thereof.
　以下の説明において、「長尺」のフィルムとは、幅に対して、５倍以上の長さを有するフィルムをいい、好ましくは１０倍若しくはそれ以上の長さを有し、具体的にはロール状に巻き取られて保管又は運搬される程度の長さを有するフィルムをいう。長尺のフィルムの長さの上限は、特に制限は無く、例えば、幅に対して１０万倍以下としうる。 In the following description, the “long” film means a film having a length of 5 times or more with respect to the width, preferably having a length of 10 times or more, and specifically, a roll. A film having a length such that the film is wound into a shape and stored or transported. The upper limit of the length of the long film is not particularly limited and may be, for example, 100,000 times or less the width.
　以下の説明において、別に断らない限り、ある層の面内位相差Ｒｅは、Ｒｅ＝（ｎｘ－ｎｙ）×ｄで表される値を示す。ある層の厚み方向の位相差Ｒｔｈは、別に断らない限り、Ｒｔｈ＝｛（ｎｘ＋ｎｙ）／２－ｎｚ｝×ｄで表される値である。さらに、ある層のＮＺ係数（ＮＺ）は、別に断らない限り、ＮＺ＝（ｎｘ－ｎｚ）／（ｎｘ－ｎｙ）で表される値を示す。ＮＺ係数は、ＮＺ＝Ｒｔｈ／Ｒｅ＋０．５により算出されうる。
　ここで、ｎｘは、層の厚み方向に垂直な方向（面内方向）であって最大の屈折率を与える方向（遅相軸方向）の屈折率を表し、ｎｙは、層の前記面内方向であってｎｘの方向に直交する方向の屈折率を表し、ｎｚは、層の厚み方向の屈折率を表し、ｄは、層の厚みを表す。測定波長は、別に断らない限り、５９０ｎｍである。 In the following description, unless otherwise specified, the in-plane retardation Re of a certain layer indicates a value represented by Re=(nx−ny)×d. The phase difference Rth in the thickness direction of a certain layer is a value represented by Rth={(nx+ny)/2−nz}×d unless otherwise specified. Further, the NZ coefficient (NZ) of a certain layer indicates a value represented by NZ=(nx−nz)/(nx−ny) unless otherwise specified. The NZ coefficient can be calculated by NZ=Rth/Re+0.5.
Here, nx represents the refractive index in the direction perpendicular to the thickness direction of the layer (in-plane direction) and giving the maximum refractive index (slow axis direction), and ny represents the in-plane direction of the layer. And nz represents the refractive index in the thickness direction of the layer, and d represents the thickness of the layer. The measurement wavelength is 590 nm unless otherwise specified.
　以下の説明において、ある層の遅相軸とは、別に断らない限り、当該層の面内における遅相軸を表す。 In the following description, the slow axis of a layer indicates the in-plane slow axis of the layer unless otherwise specified.
　以下の説明において、ある面の正面方向とは、別に断らない限り、当該面の法線方向を意味し、具体的には前記面の極角０°且つ方位角０°の方向を指す。 In the following description, the frontal direction of a surface means the normal direction of the surface unless specifically stated otherwise, and specifically refers to the direction with the polar angle of 0° and the azimuth angle of 0°.
　以下の説明において、ある面の傾斜方向とは、別に断らない限り、当該面に平行でも垂直でもない方向を意味し、具体的には当該面の極角が０°より大きく９０°より小さい範囲の方向を指す。 In the following description, the inclination direction of a surface means a direction that is neither parallel nor perpendicular to the surface unless specifically stated otherwise, and specifically, a range in which the polar angle of the surface is larger than 0° and smaller than 90°. Point in the direction of.
　以下の説明において、要素の方向が「平行」、「垂直」及び「直交」とは、別に断らない限り、本発明の効果を損ねない範囲内、例えば±５°の範囲内での誤差を含んでいてもよい。 In the following description, the terms “parallel”, “vertical”, and “orthogonal” of the directions of elements include an error within a range that does not impair the effects of the present invention, for example, a range of ±5°, unless otherwise specified. You can leave.
　以下の説明において、長尺状のフィルムの長手方向は、通常は製造ラインにおけるフィルムの流れ方向と平行である。 In the following description, the longitudinal direction of the long film is usually parallel to the film flow direction in the production line.
　以下の説明において、「偏光板」、「円偏光板」、「プレート」、及び「λ／２板」、「λ／４板」とは、別に断らない限り、剛直な部材だけでなく、例えば樹脂製のフィルムのように可撓性を有する部材も含む。 In the following description, “polarizing plate”, “circular polarizing plate”, “plate”, and “λ/2 plate” and “λ/4 plate” are not limited to rigid members, for example, unless otherwise specified. It also includes a flexible member such as a resin film.
　以下の説明において、複数の層を備える部材における各層の光学軸（吸収軸、透過軸、遅相軸等）がなす角度は、別に断らない限り、前記の層を厚み方向から見たときの角度を表す。 In the following description, the angle formed by the optical axis (absorption axis, transmission axis, slow axis, etc.) of each layer in a member including a plurality of layers is the angle when the layer is viewed from the thickness direction unless otherwise specified. Represents.
　以下の説明において、「正の固有複屈折値を有する重合体」及び「正の固有複屈折値を有する樹脂」とは、「延伸方向の屈折率が延伸方向に直交する方向の屈折率よりも大きくなる重合体」及び「延伸方向の屈折率が延伸方向に直交する方向の屈折率よりも大きくなる樹脂」をそれぞれ意味する。また、「負の固有複屈折値を有する重合体」及び「負の固有複屈折値を有する樹脂」とは、「延伸方向の屈折率が延伸方向に直交する方向の屈折率よりも小さくなる重合体」及び「延伸方向の屈折率が延伸方向に直交する方向の屈折率よりも小さくなる樹脂」をそれぞれ意味する。固有複屈折値は、誘電率分布から計算しうる。 In the following description, "polymer having a positive intrinsic birefringence value" and "resin having a positive intrinsic birefringence value" means "the refractive index in the stretching direction is more than the refractive index in the direction orthogonal to the stretching direction. It means a "polymer which becomes larger" and "a resin whose refractive index in the stretching direction is larger than that in the direction orthogonal to the stretching direction", respectively. Further, "a polymer having a negative intrinsic birefringence value" and "a resin having a negative intrinsic birefringence value" mean that a polymer having a refractive index in the stretching direction smaller than that in the direction orthogonal to the stretching direction. It means "combined" and "resin whose refractive index in the stretching direction is smaller than that in the direction orthogonal to the stretching direction", respectively. The intrinsic birefringence value can be calculated from the dielectric constant distribution.
　以下の説明において、接着剤とは、別に断らない限り、狭義の接着剤のみならず、２３℃における剪断貯蔵弾性率が１ＭＰａ未満である粘着剤をも包含する。狭義の接着剤とは、エネルギー線照射後、あるいは加熱処理後、２３℃における剪断貯蔵弾性率が１ＭＰａ～５００ＭＰａである接着剤を表す。 In the following description, unless otherwise specified, the adhesive includes not only an adhesive in a narrow sense, but also an adhesive having a shear storage elastic modulus at 23° C. of less than 1 MPa. The adhesive in a narrow sense means an adhesive having a shear storage elastic modulus at 23° C. of 1 MPa to 500 MPa after irradiation with energy rays or after heat treatment.
　［実施形態１］
　以下、本発明の実施形態１に係る円偏光板及び、当該円偏光板を備える画像表示装置について図１を参照しつつ、説明する。図１は、実施形態１に係る円偏光板を模式的に示す分解斜視図である。 [Embodiment 1]
Hereinafter, a circularly polarizing plate according to Embodiment 1 of the present invention and an image display device including the circularly polarizing plate will be described with reference to FIG. FIG. 1 is an exploded perspective view schematically showing the circularly polarizing plate according to the first embodiment.
　本実施形態の円偏光板５００は、図１に示すように、直線偏光子１３０と、本実施形態の光学異方性積層体１００と、を備える。 As shown in FIG. 1, the circularly polarizing plate 500 of this embodiment includes a linear polarizer 130 and the optically anisotropic laminate 100 of this embodiment.
　［１．光学異方性積層体］
　［１－１．光学異方性積層体の構成］
　本実施形態の光学異方性積層体１００は、第１光学異方性層１１０及び第２光学異方性層１２０を含む。光学異方性積層体１００は、必要に応じて、任意の層（図示せず）を備えていてもよい。 [1. Optically anisotropic laminate]
[1-1. Configuration of Optically Anisotropic Laminate]
The optically anisotropic layered product 100 of this embodiment includes a first optically anisotropic layer 110 and a second optically anisotropic layer 120. The optically anisotropic layered product 100 may include any layer (not shown) as necessary.
　本実施形態において、第１光学異方性層１１０は、下記式（１）を満たし、第２光学異方性層１２０は、下記式（２）を満たし、光学異方性積層体１００は、式（３）を満たし、第１光学異方性層及び第２光学異方性層が、下記式（４）を満たし、第１光学異方性層１１０の遅相軸１１１と第２光学異方性層１２０の遅相軸１２１とのなす角度が８５°～９５°である。 In the present embodiment, the first optically anisotropic layer 110 satisfies the following formula (1), the second optically anisotropic layer 120 satisfies the following formula (2), and the optically anisotropic laminate 100 is Formula (3) is satisfied, the first optical anisotropic layer and the second optical anisotropic layer satisfy the following formula (4), and the slow axis 111 of the first optical anisotropic layer 110 and the second optical anisotropic layer 110 The angle formed by the slow axis 121 of the anisotropic layer 120 is 85° to 95°.
　式（１）～式（４）を満たす光学特性を有し、かつ、第１光学異方性層１１０の遅相軸１１１と第２光学異方性層１２０の遅相軸１２１とのなす角度が８５°～９５°である光学異方性積層体１００を、直線偏光子１３０と組み合わせて得られる円偏光板５００を画像表示装置に設けることにより、その画像表示装置の表示面を傾斜方向から見た場合に外光の反射を抑制して、色付きを効果的に抑制できる。 Angles formed by the slow axis 111 of the first optically anisotropic layer 110 and the slow axis 121 of the second optically anisotropic layer 120, which have optical characteristics satisfying the equations (1) to (4). By providing the circularly polarizing plate 500 obtained by combining the optically anisotropic laminate 100 having an angle of 85° to 95° with the linear polarizer 130 in the image display device, the display surface of the image display device is tilted from the tilt direction. When viewed, the reflection of external light can be suppressed, and coloring can be effectively suppressed.
　ｎｘ１＞ｎｙ１≧ｎｚ１　　　　　　　　　　　　　式（１）
　ｎｚ２＞ｎｘ２＞ｎｙ２　　　　　　　　　　　　　式（２）
　Ｒｅ（４５０）＜Ｒｅ（５５０）＜Ｒｅ（６５０）　式（３）
　－０．３≦ＮＺ１＋ＮＺ２≦０．８　　　　　　　　式（４） nx1>ny1≧nz1 Formula (1)
nz2>nx2>ny2 Formula (2)
Re(450)<Re(550)<Re(650) Formula (3)
−0.3≦NZ1+NZ2≦0.8 Formula (4)
　前記式（１）において、ｎｘ１は、第１光学異方性層の面内方向であって最大の屈折率を与える方向の屈折率を表し、ｎｙ１は、第１光学異方性層の面内方向であって、ｎｘ１を与える方向に直交する方向の屈折率を表し、ｎｚ１は、第１光学異方性層の厚み方向の屈折率を表す。 In the formula (1), nx1 represents a refractive index in the in-plane direction of the first optically anisotropic layer, which gives the maximum refractive index, and ny1 represents in-plane of the first optically anisotropic layer. Direction, which is the refractive index in the direction orthogonal to the direction that gives nx1, and nz1 represents the refractive index in the thickness direction of the first optically anisotropic layer.
　前記式（１）は、第１光学異方性層が、いわゆるポジティブＡプレート又はネガティブＢプレートとして機能しうることを示す。 The above formula (1) shows that the first optically anisotropic layer can function as a so-called positive A plate or negative B plate.
　前記式（１）を満たす層の材料としては、耐熱性が高い材料を用いうるので、このような材料を第１光学異方性層の材料として採用することにより、加熱試験後に表示面の色味が変化することが抑制された画像表示装置を容易に実現できる。 Since a material having high heat resistance can be used as the material of the layer satisfying the formula (1), by adopting such a material as the material of the first optically anisotropic layer, the color of the display surface after the heating test is It is possible to easily realize an image display device in which the change in taste is suppressed.
　前記式（２）において、ｎｘ２は、第２光学異方性層の面内方向であって最大の屈折率を与える方向の屈折率を表し、ｎｙ２は、第２光学異方性層の面内方向であって、ｎｘ２を与える方向に直交する方向の屈折率を表し、ｎｚ２は、第２光学異方性層の厚み方向の屈折率を表す。 In the above formula (2), nx2 represents the refractive index in the in-plane direction of the second optically anisotropic layer, which gives the maximum refractive index, and ny2 represents the in-plane direction of the second optically anisotropic layer. Direction, which is the refractive index in the direction orthogonal to the direction that gives nx2, and nz2 represents the refractive index in the thickness direction of the second optically anisotropic layer.
　前記式（２）は、第２光学異方性層が、いわゆるポジティブＢプレートとして機能しうることを示す。第２光学異方性層が、式（２）を満たすことにより、反射光による色付きを効果的に抑制できる画像表示装置を実現できる。式（２）は、第２光学異方性層が、３方向の屈折率（ｎｘ２、ｎｙ２およびｎｚ２）が相違する層であること、即ち、二軸性を有する層であることを示す。 The above formula (2) shows that the second optically anisotropic layer can function as a so-called positive B plate. When the second optically anisotropic layer satisfies the expression (2), it is possible to realize an image display device that can effectively suppress coloring due to reflected light. Formula (2) indicates that the second optically anisotropic layer is a layer having different refractive indices (nx2, ny2, and nz2) in three directions, that is, a layer having biaxiality.
　前記式（３）において、Ｒｅ（４５０）、Ｒｅ（５５０）、及びＲｅ（６５０）は、波長４５０ｎｍ、５５０ｎｍ、及び６５０ｎｍにおける光学異方性積層体の面内位相差をそれぞれ表す。 In the formula (3), Re(450), Re(550) and Re(650) represent the in-plane retardation of the optically anisotropic laminate at wavelengths of 450 nm, 550 nm and 650 nm, respectively.
　前記式（３）は、光学異方性積層体の面内位相差が、逆波長分散性であることを示す。光学異方性積層体が、式（３）を満たすことにより、広い波長範囲において、光学異方性積層体を透過する光の偏光状態を均一に変換できる。よって、反射光による色付きを、広い波長範囲において効果的に抑制できる画像表示装置を実現できる。 The above formula (3) shows that the in-plane retardation of the optically anisotropic laminate has inverse wavelength dispersion. By satisfying the expression (3), the optically anisotropic laminate can uniformly convert the polarization state of light transmitted through the optically anisotropic laminate in a wide wavelength range. Therefore, it is possible to realize an image display device capable of effectively suppressing coloring due to reflected light in a wide wavelength range.
　前記式（４）において、ＮＺ１は第１光学異方性層のＮＺ係数を表し、ＮＺ２は第２光学異方性層のＮＺ係数を表す。ＮＺ１とＮＺ２の和（ＮＺ１＋ＮＺ２）は、－０．３以上、好ましくは０以上、より好ましくは０．１５以上であり、０．８以下、好ましくは０．７５以下、より好ましくは０．６５以下である。ＮＺ１とＮＺ２との和を前記の範囲に収めることにより、表示面を傾斜方向から見た場合の反射光による色付きをより効果的に抑制できる画像表示装置を実現できる。 In the formula (4), NZ1 represents the NZ coefficient of the first optically anisotropic layer, and NZ2 represents the NZ coefficient of the second optically anisotropic layer. The sum of NZ1 and NZ2 (NZ1+NZ2) is −0.3 or more, preferably 0 or more, more preferably 0.15 or more, and 0.8 or less, preferably 0.75 or less, more preferably 0.65 or less. Is. By setting the sum of NZ1 and NZ2 within the above range, it is possible to realize an image display device that can more effectively suppress coloring due to reflected light when the display surface is viewed from the tilt direction.
　ＮＺ１は（ｎｘ１－ｎｚ１）／（ｎｘ１－ｎｙ１）で算出される値であり、式（１）から、ＮＺ１は正の値である。ＮＺ１は、好ましくは１．０以上、より好ましくは１．０５以上であり、好ましくは１．３以下、より好ましくは１．２以下である。 NZ1 is a value calculated by (nx1-nz1)/(nx1-ny1), and from equation (1), NZ1 is a positive value. NZ1 is preferably 1.0 or more, more preferably 1.05 or more, preferably 1.3 or less, more preferably 1.2 or less.
　ＮＺ２は（ｎｘ２－ｎｚ２）／（ｎｘ２－ｎｙ２）で算出される値であり、式（２）から、ＮＺ２は負の値である。ＮＺ２は、好ましくは－２．０以上、より好ましくは－１．５以上であり、好ましくは－０．２以下、より好ましくは－０．４以下である。ＮＺ２を前記範囲に収めることにより、２軸性を高めることができる。 NZ2 is a value calculated by (nx2-nz2)/(nx2-ny2), and from equation (2), NZ2 is a negative value. NZ2 is preferably −2.0 or more, more preferably −1.5 or more, preferably −0.2 or less, more preferably −0.4 or less. By setting NZ2 within the above range, biaxiality can be enhanced.
　第１光学異方性層及び、第２光学異方性層は下記式（５）および（６）を満たす光学特性を有していることが好ましい。
　Ｒｅ１（４５０）／Ｒｅ１（５５０）＜Ｒｅ２（４５０）／Ｒｅ２（５５０）　式（５）
　Ｒｅ１(５５０)＞Ｒｅ２(５５０)　　　式（６） It is preferable that the first optically anisotropic layer and the second optically anisotropic layer have optical characteristics that satisfy the following formulas (5) and (6).
Re1(450)/Re1(550)<Re2(450)/Re2(550) Formula (5)
Re1(550)>Re2(550) Formula (6)
　前記式（５）において、Ｒｅ１（５５０）は、波長５５０ｎｍにおける第１光学異方性層の面内位相差を表し、Ｒｅ１（４５０）は波長４５０ｎｍにおける第１光学異方性層の面内位相差を表し、Ｒｅ２（５５０）は、波長５５０ｎｍにおける第２光学異方性層の面内位相差を表し、Ｒｅ２（４５０）は波長４５０ｎｍにおける第２光学異方性層の面内位相差を表す。 In the formula (5), Re1 (550) represents the in-plane retardation of the first optically anisotropic layer at a wavelength of 550 nm, and Re1 (450) is the in-plane position of the first optically anisotropic layer at a wavelength of 450 nm. Re2 (550) represents the in-plane retardation of the second optically anisotropic layer at a wavelength of 550 nm, and Re2 (450) represents the in-plane retardation of the second optically anisotropic layer at a wavelength of 450 nm. ..
　前記式（５）は、第２光学異方性層において第１光学異方性層よりも波長分散性が大きいことを示す。 The above formula (5) shows that the wavelength dispersion of the second optically anisotropic layer is larger than that of the first optically anisotropic layer.
　前記式（６）において、Ｒｅ１（５５０）は、波長５５０ｎｍにおける第１光学異方性層の面内位相差を表し、Ｒｅ２（５５０）は、波長５５０ｎｍにおける第２光学異方性層の面内位相差を表す。式（６）は第１光学異方性層のＲｅ１（５５０）が第２光学異方性層のＲｅ２（５５０）よりも大きいことを示す。 In the formula (6), Re1 (550) represents the in-plane retardation of the first optically anisotropic layer at a wavelength of 550 nm, and Re2 (550) is the in-plane retardation of the second optically anisotropic layer at a wavelength of 550 nm. Represents a phase difference. Formula (6) shows that Re1 (550) of the first optically anisotropic layer is larger than Re2 (550) of the second optically anisotropic layer.
　Ｒｅ１（５５０）とＲｅ２（５５０）との差は、好ましくは１００ｎｍ以上、より好ましくは１１０ｎｍ以上であり、好ましくは１８０ｎｍ以下、より好ましくは１６０ｎｍ以下である。 The difference between Re1 (550) and Re2 (550) is preferably 100 nm or more, more preferably 110 nm or more, preferably 180 nm or less, more preferably 160 nm or less.
　波長５９０ｎｍにおける第１光学異方性層の面内位相差Ｒｅ１（５９０）は、好ましくは２４０ｎｍ以上、より好ましくは２６０ｎｍ以上であり、好ましくは３２０ｎｍ以下、より好ましくは３００ｎｍ以下である。第１光学異方性層の面内位相差Ｒｅ１（５９０）が、前記範囲に収まることにより、表示面を傾斜方向から見た場合の反射光の色付きをより効果的に抑制できる画像表示装置を実現できる。 The in-plane retardation Re1 (590) of the first optically anisotropic layer at a wavelength of 590 nm is preferably 240 nm or more, more preferably 260 nm or more, preferably 320 nm or less, more preferably 300 nm or less. When the in-plane retardation Re1 (590) of the first optically anisotropic layer falls within the above range, an image display device capable of more effectively suppressing coloring of reflected light when the display surface is viewed from the tilt direction is provided. realizable.
　波長５９０ｎｍにおける第２光学異方性層の面内位相差Ｒｅ２（５９０）は、好ましくは１００ｎｍ以上、より好ましくは１２０ｎｍ以上であり、好ましくは１９０ｎｍ以下、より好ましくは１７０ｎｍ以下である。第２光学異方性層の面内位相差Ｒｅ２（５９０）が前記範囲に収まることにより、表示面を傾斜方向から見た場合の反射光による色付きをより効果的に抑制できる画像表示装置を実現できる。 The in-plane retardation Re2 (590) of the second optically anisotropic layer at a wavelength of 590 nm is preferably 100 nm or more, more preferably 120 nm or more, preferably 190 nm or less, more preferably 170 nm or less. When the in-plane retardation Re2 (590) of the second optically anisotropic layer falls within the above range, an image display device that can more effectively suppress coloring due to reflected light when the display surface is viewed from the tilt direction is realized. it can.
　第１光学異方性層の全光線透過率は、好ましくは８０％以上、より好ましくは８５％以上、特に好ましくは９０％以上である。
　第２光学異方性層の全光線透過率は、好ましくは８０％以上、より好ましくは８５％以上、特に好ましくは９０％以上である。 The total light transmittance of the first optically anisotropic layer is preferably 80% or more, more preferably 85% or more, and particularly preferably 90% or more.
The total light transmittance of the second optically anisotropic layer is preferably 80% or more, more preferably 85% or more, and particularly preferably 90% or more.
　第１光学異方性層のヘイズは、好ましくは５％以下、より好ましくは３％以下、特に好ましくは１％以下であり、理想的には０％である。
　第２光学異方性層のヘイズは、好ましくは５％以下、より好ましくは３％以下、特に好ましくは１％以下であり、理想的には０％である。 The haze of the first optically anisotropic layer is preferably 5% or less, more preferably 3% or less, particularly preferably 1% or less, and ideally 0%.
The haze of the second optically anisotropic layer is preferably 5% or less, more preferably 3% or less, particularly preferably 1% or less, and ideally 0%.
　第１光学異方性層の厚み及び第２光学異方性層の厚みは、前記の光学特性を有する範囲で任意に調整しうる。
　第１光学異方性層の厚みは、好ましくは０．５μｍ以上、より好ましくは１μｍ以上であり、好ましくは１５０μｍ以下、より好ましくは１００μｍ以下である。
　第２光学異方性層の厚みは、好ましくは０．５μｍ以上、より好ましくは１μｍ以上であり、好ましくは１５０μｍ以下、より好ましくは１００μｍ以下である。 The thickness of the first optically anisotropic layer and the thickness of the second optically anisotropic layer can be arbitrarily adjusted within the range having the above optical characteristics.
The thickness of the first optically anisotropic layer is preferably 0.5 μm or more, more preferably 1 μm or more, preferably 150 μm or less, more preferably 100 μm or less.
The thickness of the second optically anisotropic layer is preferably 0.5 μm or more, more preferably 1 μm or more, preferably 150 μm or less, more preferably 100 μm or less.
　光学異方性積層体の全光線透過率は、好ましくは８０％以上、より好ましくは８５％以上、特に好ましくは９０％以上である。 The total light transmittance of the optically anisotropic laminate is preferably 80% or more, more preferably 85% or more, and particularly preferably 90% or more.
　光学異方性積層体のヘイズは、好ましくは５％以下、より好ましくは３％以下、特に好ましくは１％以下であり、理想的には０％である。 The haze of the optically anisotropic laminate is preferably 5% or less, more preferably 3% or less, particularly preferably 1% or less, and ideally 0%.
　光学異方性積層体の厚みは、前記の光学特性を有する範囲で任意に調整しうる。具体的な厚みは、薄型化の観点から、好ましくは５μｍ以上、より好ましくは１０μｍ以上、特に好ましくは１５μｍ以上であり、好ましくは２００μｍ以下、より好ましくは１５０μｍ以下、特に好ましくは１００μｍ以下である。 The thickness of the optically anisotropic laminate can be arbitrarily adjusted within the range having the above optical characteristics. From the viewpoint of thinning, the specific thickness is preferably 5 μm or more, more preferably 10 μm or more, particularly preferably 15 μm or more, preferably 200 μm or less, more preferably 150 μm or less, particularly preferably 100 μm or less.
［１－２．第１光学異方性層及び第２光学異方性層の材料］
　第１光学異方性層及び第２光学異方性層を形成するための材料としては、例えば樹脂が挙げられ、中でも熱可塑性樹脂が好ましい。
　第１光学異方性層及び第２光学異方性層を形成するための材料としては、正の固有複屈折値を有する重合体を含む樹脂であっても、負の固有複屈折値を有する重合体を含む樹脂であっても、正の固有複屈折値を有する重合体及び負の固有複屈折値を有する重合体を含む樹脂であってもよい。 [1-2. Materials for First Optically Anisotropic Layer and Second Optically Anisotropic Layer]
As a material for forming the first optically anisotropic layer and the second optically anisotropic layer, for example, a resin can be mentioned, and among them, a thermoplastic resin is preferable.
As a material for forming the first optically anisotropic layer and the second optically anisotropic layer, even a resin containing a polymer having a positive intrinsic birefringence value has a negative intrinsic birefringence value. It may be a resin containing a polymer, or a resin containing a polymer having a positive intrinsic birefringence value and a polymer having a negative intrinsic birefringence value.
　正の固有複屈折値を有する重合体としては、特に限定されないが、例えば、ポリエチレン、ポリプロピレン等のポリオレフィン；ポリエチレンテレフタレート、ポリブチレンテレフタレート等のポリエステル；ポリフェニレンサルファイド等のポリアリーレンサルファイド；ポリビニルアルコール；ポリカーボネート；ポリアリレート；セルロースエステル、ポリエーテルスルホン；ポリスルホン；ポリアリールスルホン；ポリ塩化ビニル；環状オレフィン重合体、ノルボルネン重合体等の脂環式構造含有重合体；棒状液晶ポリマーが挙げられる。 The polymer having a positive intrinsic birefringence value is not particularly limited, but examples thereof include polyolefins such as polyethylene and polypropylene; polyesters such as polyethylene terephthalate and polybutylene terephthalate; polyarylene sulfides such as polyphenylene sulfide; polyvinyl alcohol; polycarbonate; Polyarylate; cellulose ester, polyether sulfone, polysulfone, polyaryl sulfone, polyvinyl chloride, alicyclic structure-containing polymers such as cyclic olefin polymers and norbornene polymers, and rod-shaped liquid crystal polymers.
　負の固有複屈折値を有する重合体としては、特に限定されないが、例えば、スチレン類化合物の単独重合体、並びに、スチレン類化合物と任意のモノマーとの共重合体を含むポリスチレン系重合体；ポリアクリロニトリル重合体；ポリメチルメタクリレート重合体；あるいはこれらの多元共重合ポリマーが挙げられる。また、スチレン類化合物に共重合させうる前記任意のモノマーとしては、例えば、アクリロニトリル、無水マレイン酸、メチルメタクリレート、及びブタジエンが挙げられ、アクリロニトリル、無水マレイン酸、メチルメタクリレート、及びブタジエンから選ばれる１種以上が好ましい。 The polymer having a negative intrinsic birefringence value is not particularly limited, but for example, a homopolymer of a styrene compound, and a polystyrene polymer including a copolymer of a styrene compound and an arbitrary monomer; Examples thereof include an acrylonitrile polymer; a polymethylmethacrylate polymer; or a polycopolymer of these. Examples of the arbitrary monomer copolymerizable with the styrene compound include acrylonitrile, maleic anhydride, methyl methacrylate, and butadiene, and one selected from acrylonitrile, maleic anhydride, methyl methacrylate, and butadiene. The above is preferable.
　前記の重合体は、単独重合体でもよく、共重合体でもよい。
　また、前記の重合体は、１種類を単独で用いてもよく、２種類以上を任意の比率で組み合わせて用いてもよい。 The above-mentioned polymer may be a homopolymer or a copolymer.
Moreover, the said polymer may be used individually by 1 type, and may be used in combination of 2 or more types in arbitrary ratios.
　第１光学異方性層及び第２光学異方性層を形成するための樹脂は、前記重合体以外に、任意の配合剤を含んでいてもよい。配合剤の例としては、酸化防止剤、熱安定剤、光安定剤、耐候安定剤、紫外線吸収剤、近赤外線吸収剤等の安定剤；可塑剤；などが挙げられる。配合剤は、１種類を用いてもよく、２種類以上を任意の比率で組み合わせて用いてもよい。 The resin for forming the first optically anisotropic layer and the second optically anisotropic layer may contain an optional compounding agent in addition to the polymer. Examples of the compounding agent include stabilizers such as antioxidants, heat stabilizers, light stabilizers, weather resistance stabilizers, ultraviolet absorbers and near infrared absorbers; plasticizers and the like. As the compounding agent, one kind may be used, or two or more kinds may be used in combination at an arbitrary ratio.
　第１光学異方性層は、液晶配向層を含む層であってもよい。液晶配向層については［１－３－２］において、説明する。 The first optically anisotropic layer may be a layer including a liquid crystal alignment layer. The liquid crystal alignment layer will be described in [1-3-2].
　［１－３．好適な第１光学異方性層の材料］
　［１－３－１．正の固有複屈折値を有する樹脂］
　第１光学異方性層は、第１樹脂フィルムの延伸フィルムとしうる。第１樹脂フィルムは、正の固有複屈折値を有する樹脂を含むことが好ましい。このような正の固有複屈折値を有する樹脂としては、脂環式構造含有重合体を含む樹脂、セルロースエステルを含む樹脂、及びポリカーボネートを含む樹脂が挙げられる。第１樹脂フィルムとしては、脂環式構造含有重合体を含む樹脂、セルロースエステルを含む樹脂、及びポリカーボネートを含む樹脂から選ばれる１種以上を含むことがより好ましく、脂環式構造含有重合体を含む樹脂を含むことが更に好ましい。正の固有複屈折値を有する樹脂を材料として用いることにより、該樹脂で形成された第１樹脂フィルムを延伸することにより、容易に式（１）を満たす第１光学異方性層を製造しうる。第１光学異方性層は、正の固有複屈折値を有する樹脂からなるフィルム（第１樹脂フィルム）を延伸してなる層としうる。第１樹脂フィルムは第１光学異方性層を形成する延伸前の樹脂フィルムのことをいう。 [1-3. Suitable Material of First Optically Anisotropic Layer]
[1-3-1. Resin with a positive intrinsic birefringence value]
The first optically anisotropic layer may be a stretched film of the first resin film. The first resin film preferably contains a resin having a positive intrinsic birefringence value. Examples of the resin having such a positive intrinsic birefringence value include a resin containing an alicyclic structure-containing polymer, a resin containing cellulose ester, and a resin containing polycarbonate. The first resin film more preferably contains at least one selected from a resin containing an alicyclic structure-containing polymer, a resin containing a cellulose ester, and a resin containing a polycarbonate. It is more preferable to include a resin containing. By using a resin having a positive intrinsic birefringence value as a material, the first resin film formed of the resin is stretched to easily produce the first optically anisotropic layer satisfying the formula (1). sell. The first optically anisotropic layer may be a layer formed by stretching a film (first resin film) made of a resin having a positive intrinsic birefringence value. The first resin film refers to a resin film that has not yet been stretched to form the first optically anisotropic layer.
　脂環式構造含有重合体は、繰り返し単位中に脂環式構造を有する重合体であり、通常は非晶質の重合体である。脂環式構造含有重合体としては、主鎖中に脂環式構造を含有する重合体及び側鎖に脂環式構造を含有する重合体のいずれも用いうる。
　脂環式構造としては、例えば、シクロアルカン構造、シクロアルケン構造等が挙げられるが、熱安定性等の観点からシクロアルカン構造が好ましい。
　１つの脂環式構造の繰り返し単位を構成する炭素原子数に特に制限はないが、好ましくは４個以上、より好ましくは５個以上、特に好ましくは６個以上であり、好ましくは３０個以下、より好ましくは２０個以下、特に好ましくは１５個以下である。 The alicyclic structure-containing polymer is a polymer having an alicyclic structure in the repeating unit, and is usually an amorphous polymer. As the alicyclic structure-containing polymer, both a polymer having an alicyclic structure in its main chain and a polymer having an alicyclic structure in its side chain can be used.
Examples of the alicyclic structure include a cycloalkane structure and a cycloalkene structure, and the cycloalkane structure is preferable from the viewpoint of thermal stability and the like.
The number of carbon atoms constituting one repeating unit of the alicyclic structure is not particularly limited, but preferably 4 or more, more preferably 5 or more, particularly preferably 6 or more, preferably 30 or less, The number is more preferably 20 or less, and particularly preferably 15 or less.
　脂環式構造含有重合体中の脂環式構造を有する繰り返し単位の割合は、使用目的に応じて適宜選択されうるが、好ましくは５０重量％以上、より好ましくは７０重量％以上、特に好ましくは９０重量％以上である。脂環式構造を有する繰り返し単位を前記のように多くすることにより、第１光学異方性層の耐熱性を高くできる。 The proportion of repeating units having an alicyclic structure in the alicyclic structure-containing polymer may be appropriately selected according to the purpose of use, but is preferably 50% by weight or more, more preferably 70% by weight or more, particularly preferably It is 90% by weight or more. By increasing the number of repeating units having an alicyclic structure as described above, the heat resistance of the first optically anisotropic layer can be increased.
　脂環式構造含有重合体は、例えば、（１）ノルボルネン重合体、（２）単環の環状オレフィン重合体、（３）環状共役ジエン重合体、（４）ビニル脂環式炭化水素重合体、及びこれらの水素添加物などが挙げられる。これらの中でも、環状オレフィン重合体及びノルボルネン重合体がより好ましい。 Examples of the alicyclic structure-containing polymer include (1) norbornene polymer, (2) monocyclic cycloolefin polymer, (3) cyclic conjugated diene polymer, (4) vinyl alicyclic hydrocarbon polymer, And hydrogenated products thereof. Among these, a cyclic olefin polymer and a norbornene polymer are more preferable.
　ノルボルネン重合体としては、例えば、ノルボルネンモノマーの開環重合体、ノルボルネンモノマーと開環共重合可能なその他のモノマーとの開環共重合体、及びそれらの水素添加物；ノルボルネンモノマーの付加重合体、ノルボルネンモノマーと共重合可能なその他のモノマーとの付加共重合体などが挙げられる。これらの中でも、透明性の観点から、ノルボルネンモノマーの開環重合体水素添加物が特に好ましい。 Examples of the norbornene polymer include ring-opening polymers of norbornene monomers, ring-opening copolymers of norbornene monomers with other monomers capable of ring-opening copolymerization, and hydrogenated products thereof; addition polymers of norbornene monomers, Examples thereof include addition copolymers of norbornene monomers and other monomers copolymerizable therewith. Among these, a hydrogenated product of a ring-opening polymer of a norbornene monomer is particularly preferable from the viewpoint of transparency.
　前記の脂環式構造含有重合体は、例えば特開２００２－３２１３０２号公報等に開示されている公知の重合体から選ばれる。 The alicyclic structure-containing polymer is selected from known polymers disclosed in, for example, JP-A-2002-321302.
　セルロースエステルとしては、セルロースの低級脂肪酸エステル（例：セルロースアセテート、セルロースアセテートブチレート及びセルロースアセテートプロピオネート）が代表的である。低級脂肪酸は、１分子あたりの炭素原子数６以下の脂肪酸を意味する。セルロースアセテートには、トリアセチルセルロース（ＴＡＣ）及びセルロースジアセテート（ＤＡＣ）が含まれる。 As a cellulose ester, a lower fatty acid ester of cellulose (eg, cellulose acetate, cellulose acetate butyrate and cellulose acetate propionate) is typical. The lower fatty acid means a fatty acid having 6 or less carbon atoms per molecule. Cellulose acetate includes triacetyl cellulose (TAC) and cellulose diacetate (DAC).
　セルロースエステルの総アシル基置換度は、好ましくは２．２０以上２．７０以下であり、より好ましくは２．４０以上２．６０以下である。ここで、総アシル基は、ＡＳＴＭ　Ｄ８１７－９１に準じて測定しうる。 The total acyl group substitution degree of the cellulose ester is preferably 2.20 or more and 2.70 or less, and more preferably 2.40 or more and 2.60 or less. Here, the total acyl group can be measured according to ASTM D817-91.
　セルロースエステルの重量平均重合度は、好ましくは３５０以上８００以下であり、より好ましくは３７０以上６００以下である。セルロースエステルの数平均分子量は、好ましくは６００００以上２３００００以下であり、より好ましくは７００００以上２３００００以下である。 The weight average degree of polymerization of the cellulose ester is preferably 350 or more and 800 or less, more preferably 370 or more and 600 or less. The number average molecular weight of the cellulose ester is preferably 60,000 or more and 230,000 or less, more preferably 70,000 or more and 230,000 or less.
　ポリカーボネートとしては、ジヒドロキシ化合物から誘導される構成単位及びカーボネート構造（－Ｏ－（Ｃ＝Ｏ）－Ｏ－で表される構造）を有する重合体が挙げられる。
　ジヒドロキシ化合物としては、例えば、ビスフェノールＡが挙げられる。ポリカーボネート中に含まれる、ジヒドロキシ化合物から誘導される構成単位は、１種であっても２種以上であってもよい。 Examples of the polycarbonate include polymers having a structural unit derived from a dihydroxy compound and a carbonate structure (a structure represented by —O—(C═O)—O—).
Examples of the dihydroxy compound include bisphenol A. The constitutional unit derived from the dihydroxy compound contained in the polycarbonate may be one type or two or more types.
　第１光学異方性層は、トリアセチルセルロースを含む樹脂を含むことが更に好ましい。トリアセチルセルロースを含む樹脂から形成されたフィルムのレターデーションは、一般に逆波長分散性を有することから、反射光による色付きを、広い波長範囲においてより効果的に抑制できる画像表示装置を実現できる。 More preferably, the first optically anisotropic layer contains a resin containing triacetyl cellulose. Since the retardation of a film formed of a resin containing triacetyl cellulose generally has a reverse wavelength dispersibility, it is possible to realize an image display device that can more effectively suppress coloring due to reflected light in a wide wavelength range.
　第１光学異方性層を、トリアセチルセルロースを含む樹脂で形成する場合、第１光学異方性層は、溶液流延法により形成された層であることが好ましい。これにより、容易に式（１）を満たす第１光学異方性層を製造しうる。 When the first optically anisotropic layer is made of a resin containing triacetyl cellulose, the first optically anisotropic layer is preferably a layer formed by a solution casting method. Thereby, the first optically anisotropic layer satisfying the formula (1) can be easily manufactured.
　［１－３－２．液晶配向層］
　第１光学異方性層は液晶配向層を含む層としうる。
　液晶配向層は、配向した液晶化合物を含む液晶組成物の層を硬化させた硬化物層である。よって、液晶配向層は、液晶組成物の硬化物で形成されているので、液晶化合物の分子を含む。 [1-3-2. Liquid crystal alignment layer]
The first optically anisotropic layer may be a layer including a liquid crystal alignment layer.
The liquid crystal alignment layer is a cured product layer obtained by curing a layer of a liquid crystal composition containing an aligned liquid crystal compound. Therefore, since the liquid crystal alignment layer is formed of the cured product of the liquid crystal composition, it contains molecules of the liquid crystal compound.
　液晶化合物は、重合性を有することが好ましい。よって、液晶化合物は、その分子が、アクリロイル基、メタクリロイル基、及びエポキシ基等の重合性基を含むことが好ましい。液晶化合物の分子１つ当たりの重合性基の数は、１個でもよいが、２個以上が好ましい。重合性を有する液晶化合物は、液晶相を呈した状態で重合し、液晶相における分子の屈折率楕円体において最大の屈折率を示す方向を変化させないように重合体となることができる。よって、液晶配向層において液晶化合物の配向状態を固定したり、液晶化合物の重合度を高めて液晶配向層の機械的強度を高めたりすることが可能である。 The liquid crystal compound preferably has polymerizability. Therefore, the liquid crystal compound preferably has a molecule containing a polymerizable group such as an acryloyl group, a methacryloyl group, and an epoxy group. The number of polymerizable groups per molecule of the liquid crystal compound may be one, but is preferably two or more. The polymerizable liquid crystal compound can be polymerized in a state of exhibiting a liquid crystal phase so as not to change the direction of the maximum refractive index in the refractive index ellipsoid of the molecules in the liquid crystal phase. Therefore, it is possible to fix the alignment state of the liquid crystal compound in the liquid crystal alignment layer or increase the polymerization degree of the liquid crystal compound to enhance the mechanical strength of the liquid crystal alignment layer.
　液晶化合物の分子量は、好ましくは３００以上、より好ましくは５００以上、特に好ましくは８００以上であり、好ましくは２０００以下、より好ましくは１７００以下、特に好ましくは１５００以下である。このような範囲の分子量を有する液晶化合物を用いる場合に、液晶組成物の塗工性を特に良好にできる。 The molecular weight of the liquid crystal compound is preferably 300 or more, more preferably 500 or more, particularly preferably 800 or more, preferably 2000 or less, more preferably 1700 or less, and particularly preferably 1500 or less. When a liquid crystal compound having a molecular weight in such a range is used, the coatability of the liquid crystal composition can be made particularly good.
　測定波長５９０ｎｍにおける液晶化合物の複屈折Δｎは、好ましくは０．０１以上、より好ましくは０．０３以上であり、好ましくは０．１５以下、より好ましくは０．１０以下である。このような範囲の複屈折Δｎを有する液晶化合物を用いる場合に、配向欠陥の少ない液晶硬化層を得やすい。 The birefringence Δn of the liquid crystal compound at a measurement wavelength of 590 nm is preferably 0.01 or more, more preferably 0.03 or more, preferably 0.15 or less, more preferably 0.10. When a liquid crystal compound having a birefringence Δn in such a range is used, it is easy to obtain a liquid crystal cured layer with few alignment defects.
　液晶化合物は、１種類を単独で用いてもよく、２種類以上を任意の比率で組み合わせて用いてもよい。 The liquid crystal compound may be used alone or in combination of two or more kinds at an arbitrary ratio.
　このような液晶化合物の例としては、下記式（Ｉ）で表される液晶化合物が挙げられる。 Examples of such liquid crystal compounds include liquid crystal compounds represented by the following formula (I).
Figure JPOXMLDOC01-appb-C000001
Figure JPOXMLDOC01-appb-C000001
　式（Ｉ）において、Ａｒは、芳香族複素環、複素環、および芳香族炭化水素環の少なくとも１つを有し、置換されていてもよい、炭素原子数６～６７の２価の有機基を表す。芳香族複素環としては、例えば、１Ｈ－イソインドール－１，３（２Ｈ）－ジオン環、１－ベンゾフラン環、２－ベンゾフラン環、アクリジン環、イソキノリン環、イミダゾール環、インドール環、オキサジアゾール環、オキサゾール環、オキサゾロピラジン環、オキサゾロピリジン環、オキサゾロピリダジル環、オキサゾロピリミジン環、キナゾリン環、キノキサリン環、キノリン環、シンノリン環、チアジアゾール環、チアゾール環、チアゾロピラジン環、チアゾロピリジン環、チアゾロピリダジン環、チアゾロピリミジン環、チオフェン環、トリアジン環、トリアゾール環、ナフチリジン環、ピラジン環、ピラゾール環、ピラノン環、ピラン環、ピリジン環、ピリダジン環、ピリミジン環、ピロール環、フェナントリジン環、フタラジン環、フラン環、ベンゾ［ｃ］チオフェン環、ベンゾイソオキサゾール環、ベンゾイソチアゾール環、ベンゾイミダゾール環、ベンゾオキサジアゾール環、ベンゾオキサゾール環、ベンゾチアジアゾール環、ベンゾチアゾール環、ベンゾチオフェン環、ベンゾトリアジン環、ベンゾトリアゾール環、ベンゾピラゾール環、ベンゾピラノン環等が挙げられる。複素環としては、例えば、１，３－ジチオラン環、ピロリジン、ピペラジン等が挙げられる。芳香族炭化水素環としては、例えば、フェニル環、ナフタレン環等が挙げられる。 In the formula (I), Ar has at least one of an aromatic heterocycle, a heterocycle, and an aromatic hydrocarbon ring, and is an optionally substituted divalent organic group having 6 to 67 carbon atoms. Represents. Examples of the aromatic heterocycle include 1H-isoindole-1,3(2H)-dione ring, 1-benzofuran ring, 2-benzofuran ring, acridine ring, isoquinoline ring, imidazole ring, indole ring, oxadiazole ring. , Oxazole ring, oxazolopyrazine ring, oxazolopyridine ring, oxazolopyridazyl ring, oxazolopyrimidine ring, quinazoline ring, quinoxaline ring, quinoline ring, cinnoline ring, thiadiazole ring, thiazole ring, thiazolopyrazine ring, thia Zolopyridine ring, thiazolopyridazine ring, thiazolopyrimidine ring, thiophene ring, triazine ring, triazole ring, naphthyridine ring, pyrazine ring, pyrazole ring, pyranone ring, pyran ring, pyridine ring, pyridazine ring, pyrimidine ring, pyrrole ring, Phenanthridine ring, phthalazine ring, furan ring, benzo[c]thiophene ring, benzisoxazole ring, benzisothiazole ring, benzimidazole ring, benzooxadiazole ring, benzoxazole ring, benzothiadiazole ring, benzothiazole ring, Examples thereof include a benzothiophene ring, a benzotriazine ring, a benzotriazole ring, a benzopyrazole ring, and a benzopyranone ring. Examples of the heterocycle include 1,3-dithiolane ring, pyrrolidine, piperazine and the like. Examples of the aromatic hydrocarbon ring include a phenyl ring and a naphthalene ring.
　式（Ｉ）において、Ｚ１及びＺ２は、それぞれ独立して、単結合、－Ｏ－、－Ｏ－ＣＨ２－、－ＣＨ２－Ｏ－、－Ｏ－ＣＨ２－ＣＨ２－、－ＣＨ２－ＣＨ２－Ｏ－、－Ｃ（＝Ｏ）－Ｏ－、－Ｏ－Ｃ（＝Ｏ）－、－Ｃ（＝Ｏ）－Ｓ－、－Ｓ－Ｃ（＝Ｏ）－、－ＮＲ２１－Ｃ（＝Ｏ）－、－Ｃ（＝Ｏ）－ＮＲ２１－、－ＣＦ２－Ｏ－、－Ｏ－ＣＦ２－、－ＣＨ２－ＣＨ２－、－ＣＦ２－ＣＦ２－、－Ｏ－ＣＨ２－ＣＨ２－Ｏ－、－ＣＨ＝ＣＨ－Ｃ（＝Ｏ）－Ｏ－、－Ｏ－Ｃ（＝Ｏ）－ＣＨ＝ＣＨ－、－ＣＨ２－Ｃ（＝Ｏ）－Ｏ－、－Ｏ－Ｃ（＝Ｏ）－ＣＨ２－、－ＣＨ２－Ｏ－Ｃ（＝Ｏ）－、－Ｃ（＝Ｏ）－Ｏ－ＣＨ２－、－ＣＨ２－ＣＨ２－Ｃ（＝Ｏ）－Ｏ－、－Ｏ－Ｃ（＝Ｏ）－ＣＨ２－ＣＨ２－、－ＣＨ２－ＣＨ２－Ｏ－Ｃ（＝Ｏ）－、－Ｃ（＝Ｏ）－Ｏ－ＣＨ２－ＣＨ２－、－ＣＨ＝ＣＨ－、－Ｎ＝ＣＨ－、－ＣＨ＝Ｎ－、－Ｎ＝Ｃ（ＣＨ３）－、－Ｃ（ＣＨ３）＝Ｎ－、－Ｎ＝Ｎ－、及び、－Ｃ≡Ｃ－、からなる群より選ばれるいずれかを表す。Ｒ２１は、それぞれ独立して、水素原子又は炭素原子数１～６のアルキル基を表す。 In formula (I), Z 1 and Z 2 are each independently a single bond, —O—, —O—CH 2 —, —CH 2 —O—, —O—CH 2 —CH 2 —, — CH 2 -CH 2 -O-, -C(=O)-O-, -OC(=O)-, -C(=O)-S-, -SC(=O)-,- NR 21 -C (= O) - , - C (= O) -NR 21 -, - CF 2 -O -, - O-CF 2 -, - CH 2 -CH 2 -, - CF 2 -CF 2 - , -O-CH 2 -CH 2 -O-, -CH=CH-C(=O)-O-, -OC-(=O)-CH=CH-, -CH 2 -C(=O) -O -, - O-C ( = O) -CH 2 -, - CH 2 -O-C (= O) -, - C (= O) -O-CH 2 -, - CH 2 -CH 2 - C (= O) -O -, - O-C (= O) -CH 2 -CH 2 -, - CH 2 -CH 2 -O-C (= O) -, - C (= O) -O- CH 2 -CH 2 -, -CH=CH-, -N=CH-, -CH=N-, -N=C(CH 3 )-, -C(CH 3 )=N-, -N=N- , And -C≡C-. R 21's each independently represent a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.
　式（Ｉ）において、Ａ１、Ａ２、Ｂ１及びＢ２は、それぞれ独立して、置換基を有していてもよい環状脂肪族基、及び、置換基を有していてもよい芳香族基、からなる群より選ばれる基を表す。Ａ１、Ａ２、Ｂ１及びＢ２が表す基の炭素原子数（置換基の炭素原子数を含む。）は、それぞれ独立して、通常、３～１００である。中でも、Ａ１、Ａ２、Ｂ１及びＢ２は、それぞれ独立して、置換基を有していてもよい炭素原子数５～２０の環状脂肪族基、または、置換基を有していてもよい炭素原子数２～２０の芳香族基が好ましい。 In formula (I), A 1 , A 2 , B 1 and B 2 are each independently a cyclic aliphatic group which may have a substituent, and an aromatic group which may have a substituent. Represents a group selected from the group consisting of group groups. The number of carbon atoms of the group represented by A 1 , A 2 , B 1 and B 2 (including the number of carbon atoms of the substituent) is usually 3 to 100 each independently. Among them, A 1 , A 2 , B 1 and B 2 each independently have a cycloaliphatic group having 5 to 20 carbon atoms which may have a substituent, or a substituent. Aromatic groups having 2 to 20 carbon atoms are preferable.
　Ａ１、Ａ２、Ｂ１及びＢ２における環状脂肪族基としては、例えば、シクロペンタン－１，３－ジイル基、シクロヘキサン－１，４－ジイル基、シクロヘプタン－１，４－ジイル基、シクロオクタン－１，５－ジイル基等の、炭素原子数５～２０のシクロアルカンジイル基；デカヒドロナフタレン－１，５－ジイル基、デカヒドロナフタレン－２，６－ジイル基等の、炭素原子数５～２０のビシクロアルカンジイル基；等が挙げられる。中でも、置換されていてもよい炭素原子数５～２０のシクロアルカンジイル基が好ましく、シクロヘキサンジイル基がより好ましく、シクロヘキサン－１，４－ジイル基が特に好ましい。環状脂肪族基は、トランス体であってもよく、シス体であってもよく、シス体とトランス体との混合物であってもよい。中でも、トランス体がより好ましい。 Examples of the cycloaliphatic group for A 1 , A 2 , B 1 and B 2 include a cyclopentane-1,3-diyl group, a cyclohexane-1,4-diyl group, a cycloheptane-1,4-diyl group, Cycloalkanediyl group having 5 to 20 carbon atoms such as cyclooctane-1,5-diyl group; carbon atom such as decahydronaphthalene-1,5-diyl group, decahydronaphthalene-2,6-diyl group A bicycloalkanediyl group of the number 5 to 20; and the like. Of these, an optionally substituted cycloalkanediyl group having 5 to 20 carbon atoms is preferable, a cyclohexanediyl group is more preferable, and a cyclohexane-1,4-diyl group is particularly preferable. The cycloaliphatic group may be in trans form, cis form, or a mixture of cis form and trans form. Among them, the trans form is more preferable.
　Ａ１、Ａ２、Ｂ１及びＢ２における環状脂肪族基が有しうる置換基としては、例えば、ハロゲン原子、炭素原子数１～６のアルキル基、炭素原子数１～５のアルコキシ基、ニトロ基、シアノ基等が挙げられる。置換基の数は、一つでもよく、複数でもよい。また、複数の置換基は、互いに同一であってもよく、異なっていてもよい。 Examples of the substituent that the cycloaliphatic group in A 1 , A 2 , B 1 and B 2 may have include a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, Examples thereof include a nitro group and a cyano group. The number of substituents may be one or more. Further, the plurality of substituents may be the same as or different from each other.
　Ａ１、Ａ２、Ｂ１及びＢ２における芳香族基としては、例えば、１，２－フェニレン基、１，３－フェニレン基、１，４－フェニレン基、１，４－ナフチレン基、１，５－ナフチレン基、２，６－ナフチレン基、４，４’－ビフェニレン基等の、炭素原子数６～２０の芳香族炭化水素環基；フラン－２，５－ジイル基、チオフェン－２，５－ジイル基、ピリジン－２，５－ジイル基、ピラジン－２，５－ジイル基等の、炭素原子数２～２０の芳香族複素環基；等が挙げられる。中でも、炭素原子数６～２０の芳香族炭化水素環基が好ましく、フェニレン基がさらに好ましく、１，４－フェニレン基が特に好ましい。 Examples of the aromatic group for A 1 , A 2 , B 1 and B 2 include 1,2-phenylene group, 1,3-phenylene group, 1,4-phenylene group, 1,4-naphthylene group, 1, Aromatic hydrocarbon ring group having 6 to 20 carbon atoms such as 5-naphthylene group, 2,6-naphthylene group, 4,4'-biphenylene group; furan-2,5-diyl group, thiophene-2,5 -Diyl group, pyridine-2,5-diyl group, pyrazine-2,5-diyl group and the like; aromatic heterocyclic group having 2 to 20 carbon atoms; and the like. Of these, an aromatic hydrocarbon ring group having 6 to 20 carbon atoms is preferable, a phenylene group is more preferable, and a 1,4-phenylene group is particularly preferable.
　Ａ１、Ａ２、Ｂ１及びＢ２における芳香族基が有しうる置換基としては、例えば、Ａ１、Ａ２、Ｂ１及びＢ２における環状脂肪族基が有しうる置換基と同じ例が挙げられる。置換基の数は、一つでもよく、複数でもよい。また、複数の置換基は、互いに同一であってもよく、異なっていてもよい。 The substituent which the aromatic group in A 1 , A 2 , B 1 and B 2 may have is, for example, the same as the substituent which the cyclic aliphatic group in A 1 , A 2 , B 1 and B 2 may have. An example is given. The number of substituents may be one or more. Further, the plurality of substituents may be the same as or different from each other.
　式（Ｉ）において、Ｙ１～Ｙ４は、それぞれ独立して、単結合、－Ｏ－、－Ｃ（＝Ｏ）－、－Ｃ（＝Ｏ）－Ｏ－、－Ｏ－Ｃ（＝Ｏ）－、－ＮＲ２２－Ｃ（＝Ｏ）－、－Ｃ（＝Ｏ）－ＮＲ２２－、－Ｏ－Ｃ（＝Ｏ）－Ｏ－、－ＮＲ２２－Ｃ（＝Ｏ）－Ｏ－、－Ｏ－Ｃ（＝Ｏ）－ＮＲ２２－、及び、－ＮＲ２２－Ｃ（＝Ｏ）－ＮＲ２３－、からなる群より選ばれるいずれかを表す。Ｒ２２及びＲ２３は、それぞれ独立して、水素原子又は炭素原子数１～６のアルキル基を表す。 In formula (I), Y 1 to Y 4 are each independently a single bond, —O—, —C(═O)—, —C(═O)—O—, —O—C(═O )-, -NR 22 -C(=O)-, -C(=O)-NR 22 -, -OC(=O)-O-, -NR 22 -C(=O)-O-, -O-C (= O) -NR 22 -, and, -NR 22 -C (= O) -NR 23 -, represents any one selected from the group consisting of. R 22 and R 23 each independently represent a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.
　式（Ｉ）において、Ｇ１及びＧ２は、それぞれ独立して、炭素原子数１～２０の脂肪族炭化水素基；並びに、炭素原子数３～２０の脂肪族炭化水素基に含まれるメチレン基（－ＣＨ２－）の１以上が－Ｏ－又は－Ｃ（＝Ｏ）－に置換された基；からなる群より選ばれる有機基を表す。Ｇ１及びＧ２の前記有機基に含まれる水素原子は、炭素原子数１～５のアルキル基、炭素原子数１～５のアルコキシ基、または、ハロゲン原子に置換されていてもよい。ただし、Ｇ１及びＧ２の両末端のメチレン基（－ＣＨ２－）が－Ｏ－又は－Ｃ（＝Ｏ）－に置換されることはない。 In the formula (I), G 1 and G 2 are each independently an aliphatic hydrocarbon group having 1 to 20 carbon atoms; and a methylene group contained in the aliphatic hydrocarbon group having 3 to 20 carbon atoms. Represents an organic group selected from the group consisting of one or more of (—CH 2 —) substituted with —O— or —C(═O)—. The hydrogen atom contained in the organic group of G 1 and G 2 may be substituted with an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, or a halogen atom. However, the methylene groups (—CH 2 —) at both ends of G 1 and G 2 are not replaced with —O— or —C(═O)—.
　Ｇ１及びＧ２における炭素原子数１～２０の脂肪族炭化水素基の具体例としては、炭素原子数１～２０のアルキレン基が挙げられる。 Specific examples of the aliphatic hydrocarbon group having 1 to 20 carbon atoms in G 1 and G 2 include an alkylene group having 1 to 20 carbon atoms.
　Ｇ１及びＧ２における炭素原子数３～２０の脂肪族炭化水素基の具体例としては、炭素原子数３～２０のアルキレン基が挙げられる。 Specific examples of the aliphatic hydrocarbon group having 3 to 20 carbon atoms in G 1 and G 2 include an alkylene group having 3 to 20 carbon atoms.
　式（Ｉ）において、Ｐ１及びＰ２は、それぞれ独立して、重合性基を表す。Ｐ１及びＰ２における重合性基としては、例えば、アクリロイルオキシ基、メタクリロイルオキシ基等の、ＣＨ２＝ＣＲ３１－Ｃ（＝Ｏ）－Ｏ－で表される基；ビニル基；ビニルエーテル基；ｐ－スチルベン基；アクリロイル基；メタクリロイル基；カルボキシル基；メチルカルボニル基；水酸基；アミド基；炭素原子数１～４のアルキルアミノ基；アミノ基；エポキシ基；オキセタニル基；アルデヒド基；イソシアネート基；チオイソシアネート基；等が挙げられる。Ｒ３１は、水素原子、メチル基、又は塩素原子を表す。中でも、ＣＨ２＝ＣＲ３１－Ｃ（＝Ｏ）－Ｏ－で表される基が好ましく、ＣＨ２＝ＣＨ－Ｃ（＝Ｏ）－Ｏ－（アクリロイルオキシ基）、ＣＨ２＝Ｃ（ＣＨ３）－Ｃ（＝Ｏ）－Ｏ－（メタクリロイルオキシ基）がより好ましく、アクリロイルオキシ基が特に好ましい。 In formula (I), P 1 and P 2 each independently represent a polymerizable group. Examples of the polymerizable group for P 1 and P 2 include a group represented by CH 2 ═CR 31 —C(═O)—O— such as an acryloyloxy group and a methacryloyloxy group; a vinyl group; a vinyl ether group; p-stilbene group; acryloyl group; methacryloyl group; carboxyl group; methylcarbonyl group; hydroxyl group; amide group; alkylamino group having 1 to 4 carbon atoms; amino group; epoxy group; oxetanyl group; aldehyde group; isocyanate group; thio Isocyanate group; and the like. R 31 represents a hydrogen atom, a methyl group, or a chlorine atom. Of these, a group represented by CH 2 ═CR 31 —C(═O)—O— is preferable, and CH 2 ═CH—C(═O)—O—(acryloyloxy group) and CH 2 ═C(CH 3 )-C(=O)-O-(methacryloyloxy group) is more preferable, and acryloyloxy group is particularly preferable.
　式（Ｉ）において、ｐ及びｑは、それぞれ独立して、０又は１を表す。 In the formula (I), p and q each independently represent 0 or 1.
　式（Ｉ）で表される液晶化合物は、例えば、国際公開第２０１２／１４７９０４号に記載される、ヒドラジン化合物とカルボニル化合物との反応により製造しうる。 The liquid crystal compound represented by the formula (I) can be produced, for example, by the reaction of a hydrazine compound and a carbonyl compound described in WO2012/147904.
　式（Ｉ）で表される液晶化合物としては、具体的には、例えば、下記の式で表される化合物が挙げられる。 Specific examples of the liquid crystal compound represented by the formula (I) include compounds represented by the following formulas.
Figure JPOXMLDOC01-appb-C000002
Figure JPOXMLDOC01-appb-C000002
　液晶組成物は、必要に応じて、液晶化合物に組み合わせて、更に任意の成分を含んでいてもよい。任意の成分は、１種類を単独で用いてもよく、２種類以上を任意の比率で組合わせて用いてもよい。 The liquid crystal composition may further contain an optional component in combination with the liquid crystal compound, if necessary. As the arbitrary component, one type may be used alone, or two or more types may be used in combination at an arbitrary ratio.
　例えば、液晶化合物の重合を促進するため、液晶組成物は、任意の成分として重合開始剤を含んでいてもよい。重合開始剤としては、熱重合開始剤及び光重合開始剤のいずれを用いてもよい。 For example, in order to accelerate the polymerization of the liquid crystal compound, the liquid crystal composition may contain a polymerization initiator as an optional component. As the polymerization initiator, either a thermal polymerization initiator or a photopolymerization initiator may be used.
　液晶組成物は、任意の成分として、界面活性剤を含んでいてもよい。特に、配向性に優れた液晶硬化層を安定して得る観点から、界面活性剤としては、分子中にフッ素原子を含む界面活性剤が好ましい。 The liquid crystal composition may include a surfactant as an optional component. Particularly, from the viewpoint of stably obtaining a liquid crystal cured layer having excellent orientation, the surfactant is preferably a surfactant containing a fluorine atom in the molecule.
　また、液晶組成物は、任意の成分として、例えば、酸化防止剤を含んでいてもよい。酸化防止剤を用いることにより、液晶組成物のゲル化を抑制できるので、液晶組成物のポットライフを長くできる。酸化防止剤は、１種類を単独で用いてもよく、２種類状を任意の比率で組み合わせて用いてもよい。 Further, the liquid crystal composition may include, for example, an antioxidant as an optional component. By using an antioxidant, gelation of the liquid crystal composition can be suppressed, so that the pot life of the liquid crystal composition can be extended. As the antioxidant, one kind may be used alone, and two kinds may be used in combination at an arbitrary ratio.
　液晶組成物は、任意の成分として、溶媒を含んでいてもよい。溶媒としては、逆分散液晶化合物を溶解できるものが好ましい。このような溶媒としては、通常、有機溶媒を用いる。 The liquid crystal composition may include a solvent as an optional component. As the solvent, those capable of dissolving the reverse dispersion liquid crystal compound are preferable. An organic solvent is usually used as such a solvent.
　液晶組成物が含みうる任意のその他の成分としては、例えば、金属；金属錯体；酸化チタン等の金属酸化物；染料、顔料等の着色剤；蛍光材料、燐光材料等の発光材料；レベリング剤；チキソ剤；ゲル化剤；多糖類；紫外線吸収剤；赤外線吸収剤；抗酸化剤；イオン交換樹脂；等が挙げられる。これらの成分の量は、液晶化合物の合計１００重量部に対して、各々０．１重量部～２０重量部としうる。 Examples of optional other components that the liquid crystal composition may include include metals; metal complexes; metal oxides such as titanium oxide; coloring agents such as dyes and pigments; luminescent materials such as fluorescent materials and phosphorescent materials; leveling agents; Examples include thixotropic agents, gelling agents, polysaccharides, ultraviolet absorbers, infrared absorbers, antioxidants, ion exchange resins, and the like. The amount of each of these components may be 0.1 to 20 parts by weight based on 100 parts by weight of the liquid crystal compound.
　液晶組成物の硬化は、通常、当該液晶組成物が含む重合性の化合物の重合によって達成される。よって、液晶配向層は、通常、液晶組成物が含んでいた成分の一部又は全部の重合体を含む。したがって、液晶化合物が重合性を有する場合、液晶配向層は、液晶化合物の重合体を含む層でありうる。通常、重合によって液晶化合物の液晶性は失われるが、本願においては、そのように重合した液晶化合物も、用語「液晶配向層に含まれる液晶化合物」に含める。 The curing of the liquid crystal composition is usually achieved by polymerizing the polymerizable compound contained in the liquid crystal composition. Therefore, the liquid crystal alignment layer usually contains a polymer of a part or all of the components included in the liquid crystal composition. Therefore, when the liquid crystal compound is polymerizable, the liquid crystal alignment layer may be a layer containing a polymer of the liquid crystal compound. Usually, the liquid crystallinity of the liquid crystal compound is lost by polymerization, but in the present application, the liquid crystal compound thus polymerized is also included in the term “liquid crystal compound contained in the liquid crystal alignment layer”.
　液晶配向層においては、液晶組成物が有していた流動性が失われる。よって、通常、液晶配向層においては、液晶化合物の配向状態が、固定されうる。用語「配向状態を固定された液晶化合物」には、前記の液晶化合物の重合体が包含される。液晶配向層は、配向状態を固定された液晶化合物の分子に組み合わせて配向状態を固定されていない液晶化合物の分子を含んでいてもよいが、液晶配向層に含まれる液晶化合物の分子の全てが配向状態を固定されていることが好ましい。 In the liquid crystal alignment layer, the fluidity of the liquid crystal composition is lost. Therefore, usually, in the liquid crystal alignment layer, the alignment state of the liquid crystal compound can be fixed. The term “liquid crystal compound having a fixed alignment state” includes a polymer of the above liquid crystal compound. The liquid crystal alignment layer may include molecules of the liquid crystal compound in which the alignment state is not fixed by combining with molecules of the liquid crystal compound in which the alignment state is fixed, but all of the molecules of the liquid crystal compound included in the liquid crystal alignment layer are included. It is preferable that the orientation state is fixed.
　液晶配向層の形成方法は特に限定されないが、例えば、基材となるフィルムに、液晶化合物を含む液晶組成物の層を形成する工程、液晶組成物の層に含まれる液晶化合物を配向させる工程、及び、液晶組成物の層を硬化させる工程を行うことにより形成しうる。 The method for forming the liquid crystal alignment layer is not particularly limited, for example, a film serving as a base material, a step of forming a layer of a liquid crystal composition containing a liquid crystal compound, a step of aligning the liquid crystal compound contained in the layer of the liquid crystal composition, Alternatively, it can be formed by performing a step of curing the layer of the liquid crystal composition.
　［１－４．好適な第２光学異方性層の材料］
　［１－４－１．負の固有複屈折値を有する樹脂］
　第２光学異方性層は、第２樹脂フィルムの延伸フィルムとしうる。第２樹脂フィルムは、負の固有複屈折値を有する樹脂を含むことが好ましい。負の固有複屈折値を有する樹脂を材料として用いることにより、該樹脂で形成された第２樹脂フィルムを延伸して容易に式（２）を満たす第２光学異方性層を製造しうる。よって、第２光学異方性層は、負の固有複屈折値を有する樹脂からなるフィルム（第２樹脂フィルム）を延伸してなる層としうる。第２樹脂フィルムは第２光学異方性層を形成する延伸前の樹脂フィルムのことをいう。 [1-4. Suitable Material for Second Optically Anisotropic Layer]
[1-4-1. Resin with negative intrinsic birefringence value]
The second optically anisotropic layer may be a stretched film of the second resin film. The second resin film preferably contains a resin having a negative intrinsic birefringence value. By using a resin having a negative intrinsic birefringence value as a material, the second resin film formed of the resin can be stretched to easily produce the second optically anisotropic layer satisfying the formula (2). Therefore, the second optically anisotropic layer may be a layer formed by stretching a film (second resin film) made of a resin having a negative intrinsic birefringence value. The second resin film refers to the resin film that has not yet been stretched to form the second optically anisotropic layer.
　負の固有複屈折値を有する樹脂は負の固有複屈折値を有する重合体を含む。
　負の固有複屈折値を有する重合体としては、位相差の発現性が高いという観点から、ポリスチレン系重合体が好ましく、さらに耐熱性が高いという点で、スチレン又はスチレン誘導体と無水マレイン酸との共重合体が特に好ましい。この場合、ポリスチレン系重合体１００重量部に対して、無水マレイン酸単位の量は、好ましくは５重量部以上、より好ましくは１０重量部以上、特に好ましくは１５重量部以上であり、好ましくは３０重量部以下、より好ましくは２８重量部以下、特に好ましくは２６重量部以下である。前記の無水マレイン酸単位とは、無水マレイン酸を重合して形成される構造を有する構造単位のことをいう。 The resin having a negative intrinsic birefringence value includes a polymer having a negative intrinsic birefringence value.
As the polymer having a negative intrinsic birefringence value, from the viewpoint of high expression of retardation, a polystyrene polymer is preferable, and in terms of high heat resistance, styrene or a styrene derivative and maleic anhydride Copolymers are particularly preferred. In this case, the amount of the maleic anhydride unit is preferably 5 parts by weight or more, more preferably 10 parts by weight or more, particularly preferably 15 parts by weight or more, and preferably 30 parts by weight with respect to 100 parts by weight of the polystyrene polymer. It is not more than 28 parts by weight, more preferably not more than 28 parts by weight, particularly preferably not more than 26 parts by weight. The maleic anhydride unit is a structural unit having a structure formed by polymerizing maleic anhydride.
　負の固有複屈折値を有する樹脂における重合体の割合は、好ましくは５０重量％～１００重量％、より好ましくは７０重量％～１００重量％、特に好ましくは９０重量％～１００重量％である。重合体の割合を前記範囲にすることにより、第２光学異方性層が適切な光学特性を発現しうる。 The proportion of the polymer in the resin having a negative intrinsic birefringence value is preferably 50% by weight to 100% by weight, more preferably 70% by weight to 100% by weight, and particularly preferably 90% by weight to 100% by weight. By setting the proportion of the polymer within the above range, the second optically anisotropic layer can exhibit appropriate optical characteristics.
　負の固有複屈折値を有する樹脂のガラス転移温度は、好ましくは８０℃以上、より好ましくは９０℃以上、更に好ましくは１００℃以上、中でも好ましくは１１０℃以上、特に好ましくは１２０℃以上である。負の固有複屈折値を有する樹脂のガラス転移温度がこのように高いことにより、負の固有複屈折値を有する樹脂の配向緩和を低減することができる。また、負の固有複屈折値を有する樹脂のガラス転移温度の上限に特に制限は無いが、通常は２００℃以下である。ガラス転移温度は、示差走査熱量分析計を用いて、ＪＩＳ　Ｋ　６９１１に基づき、昇温速度１０℃／分の条件で測定しうる。 The glass transition temperature of the resin having a negative intrinsic birefringence value is preferably 80° C. or higher, more preferably 90° C. or higher, further preferably 100° C. or higher, especially 110° C. or higher, particularly preferably 120° C. or higher. .. Such a high glass transition temperature of the resin having a negative intrinsic birefringence value can reduce orientation relaxation of the resin having a negative intrinsic birefringence value. The upper limit of the glass transition temperature of the resin having a negative intrinsic birefringence value is not particularly limited, but is usually 200° C. or lower. The glass transition temperature can be measured by using a differential scanning calorimeter at a temperature rising rate of 10° C./min based on JIS K6911.
　負の固有複屈折値を有する樹脂には、機械的強度が低いものがある。例えば、ポリスチレン系重合体を含む樹脂は、機械的強度が低い傾向がある。そこで、負の固有複屈折値を有する樹脂からなる層を含む第２光学異方性層は、負の固有複屈折値を有する樹脂を含む層に組み合わせて、負の固有複屈折値を有する樹脂を含む層を保護できる保護層を備えることが好ましい。 Some resins with negative intrinsic birefringence have low mechanical strength. For example, a resin containing a polystyrene polymer tends to have low mechanical strength. Therefore, the second optically anisotropic layer including a layer made of a resin having a negative intrinsic birefringence value is combined with a layer containing a resin having a negative intrinsic birefringence value to obtain a resin having a negative intrinsic birefringence value. It is preferable to provide a protective layer capable of protecting the layer containing.
　保護層としては、特に限定はないが、例えば、正の固有複屈折値を有する樹脂からなる層を用いうる。その際、第２光学異方性層における位相差の調整を容易にする観点から、保護層が有する面内位相差及び厚み方向の位相差はゼロに近いことが好ましい。このように保護層の面内位相差及び厚み方向の位相差をゼロに近づける方法としては、例えば、保護層に含まれる樹脂のガラス転移温度を負の固有複屈折値を有する樹脂のガラス転移温度よりも低くする方法が挙げられる。
　保護層は、負の固有複屈折値を有する樹脂からなる層の片側だけに設けられていてもよく、両側に設けられていてもよい。 The protective layer is not particularly limited, but for example, a layer made of a resin having a positive intrinsic birefringence value can be used. At that time, from the viewpoint of facilitating the adjustment of the retardation in the second optically anisotropic layer, the in-plane retardation and the retardation in the thickness direction of the protective layer are preferably close to zero. As a method for bringing the in-plane retardation and the thickness direction retardation of the protective layer close to zero, for example, the glass transition temperature of the resin contained in the protective layer is set to the glass transition temperature of the resin having a negative intrinsic birefringence value. There is a method of lowering it.
The protective layer may be provided on only one side of the layer made of a resin having a negative intrinsic birefringence value, or may be provided on both sides.
　［１－５．光学異方性積層体］
　本実施形態の光学異方性積層体において、第１光学異方性層及び第２光学異方性層のいずれか一方を、λ／２板により構成し、他方をλ／４板により構成しうる。λ／２板は、測定波長５９０ｎｍにおいて、通常２００ｎｍ以上通常３００ｎｍ以下の面内位相差を有する光学部材である。λ／４板は、測定波長５９０ｎｍにおいて、通常７５ｎｍ以上通常１５４ｎｍ以下の面内位相差を有する光学部材である。λ／２板及びλ／４板を組み合わせることにより広帯域λ／４板を実現できる。
　そのため、本実施形態に係る円偏光板は、広い波長範囲において、右円偏光及び左円偏光の一方の光を吸収し、残りの光を透過させうる機能を発現できる。したがって、このような態様の光学異方性積層体を備える円偏光板により、正面方向及び傾斜方向の両方において、広い波長範囲の光の反射を低減することが可能となる。 [1-5. Optically anisotropic laminate]
In the optically anisotropic layered product of the present embodiment, one of the first optically anisotropic layer and the second optically anisotropic layer is composed of a λ/2 plate, and the other is composed of a λ/4 plate. sell. The λ/2 plate is an optical member having an in-plane retardation of usually 200 nm or more and usually 300 nm or less at a measurement wavelength of 590 nm. The λ/4 plate is an optical member having an in-plane retardation of usually 75 nm or more and usually 154 nm or less at a measurement wavelength of 590 nm. A broadband λ/4 plate can be realized by combining the λ/2 plate and the λ/4 plate.
Therefore, the circularly polarizing plate according to the present embodiment can exhibit a function of absorbing one of right circularly polarized light and left circularly polarized light and transmitting the remaining light in a wide wavelength range. Therefore, the circularly polarizing plate provided with the optically anisotropic laminate of such an aspect makes it possible to reduce reflection of light in a wide wavelength range in both the front direction and the tilt direction.
　［１－６．光学異方性積層体の製造方法］
　本実施形態の光学異方性積層体は、正の固有複屈折値を有する樹脂を含む第１樹脂フィルムを延伸して第１光学異方性層を得る工程１と、負の固有複屈折値を有する樹脂を含む第２樹脂フィルムを延伸して第２光学異方性層を得る工程２と、前記第１光学異方性層と前記第２光学異方性層とを重ねる工程３と、を含む製造方法により製造しうる。 [1-6. Method for producing optically anisotropic laminate]
The optically anisotropic laminate of the present embodiment has a step 1 of stretching a first resin film containing a resin having a positive intrinsic birefringence value to obtain a first optically anisotropic layer, and a negative intrinsic birefringence value. A step 2 of stretching a second resin film containing a resin having a to obtain a second optically anisotropic layer, and a step 3 of stacking the first optically anisotropic layer and the second optically anisotropic layer. Can be manufactured by a manufacturing method including.
　[１－６－１．工程１]
　工程１は、正の固有複屈折値を有する樹脂を含む第１樹脂フィルムを延伸して第１光学異方性層を得る工程である。 [1-6-1. Process 1]
Step 1 is a step of stretching a first resin film containing a resin having a positive intrinsic birefringence value to obtain a first optically anisotropic layer.
　工程１で用いる正の固有複屈折値を有する樹脂を含む第１樹脂フィルムは、溶融成形法又は溶液流延法によって製造でき、溶融成形法が好ましい。また、溶融成形法の中でも、押出成形法、インフレーション成形法又はプレス成形法が好ましく、押出成形法が特に好ましい。 The first resin film containing a resin having a positive intrinsic birefringence value used in step 1 can be produced by a melt molding method or a solution casting method, and the melt molding method is preferable. Further, among the melt molding methods, the extrusion molding method, the inflation molding method or the press molding method is preferable, and the extrusion molding method is particularly preferable.
　通常、第１樹脂フィルムは、長尺の樹脂フィルムとして得られる。第１樹脂フィルムを長尺の樹脂フィルムとして用意することにより、第１光学異方性層を製造する場合に各工程の一部または全部をインラインで行うことが可能であるので、製造を簡便且つ効率的に行なうことできる。 Normally, the first resin film is obtained as a long resin film. By preparing the first resin film as a long resin film, it is possible to perform some or all of the steps in-line when manufacturing the first optically anisotropic layer, so that the manufacturing is simple and easy. It can be done efficiently.
　第１樹脂フィルムの延伸方法は、延伸により発現させたい光学特性に応じて適切な方法を任意に採用しうる。本実施形態において、第１樹脂フィルムの延伸方法としては特に限定はないが、一方向延伸（一軸延伸）が好ましい。第１樹脂フィルムを一方向延伸することにより正の固有複屈折率値を有する樹脂を含む層の一軸性を高めることができ、ＮＺ１を１．０に近づけることができる。一方向延伸には、例えば、自由端一軸延伸および固定端一軸延伸が含まれる。工程１において、第１樹脂フィルムを、一方向又は二方向に一回延伸してもよい。 As the stretching method of the first resin film, an appropriate method can be arbitrarily adopted depending on the optical characteristics to be expressed by stretching. In the present embodiment, the stretching method of the first resin film is not particularly limited, but unidirectional stretching (uniaxial stretching) is preferable. By unidirectionally stretching the first resin film, the uniaxiality of the layer containing the resin having a positive intrinsic birefringence value can be enhanced, and NZ1 can be brought close to 1.0. Unidirectional stretching includes, for example, free-end uniaxial stretching and fixed-end uniaxial stretching. In step 1, the first resin film may be stretched once in one direction or two directions.
　第１樹脂フィルムの延伸方向は、特に限定されない。第１樹脂フィルムの延伸は、斜め方向への延伸を含んでいてもよい。斜め方向への延伸を含む製造方法により、斜め延伸フィルムとしての第１光学異方性層を得ることができる。斜め延伸フィルムとは、斜め方向への延伸を含む製造方法によって製造されたフィルムを意味する。通常、斜め延伸フィルムには、その幅手方向に平行でなく垂直でもない遅相軸が発現する。よって、この斜め延伸フィルムとしての第１光学異方性層には、幅手方向に対して所定の角度をなす遅相軸を容易に発現させることができる。したがって、斜め延伸フィルムとしての第１光学異方性層は、幅手方向に透過軸を有する偏光フィルム及び第２光学異方性層とロールトゥロールで貼り合わせて、円偏光板を容易に製造できる。 The stretching direction of the first resin film is not particularly limited. Stretching of the first resin film may include stretching in an oblique direction. The first optically anisotropic layer as an obliquely stretched film can be obtained by a production method including stretching in an oblique direction. The obliquely stretched film means a film produced by a production method including stretching in an oblique direction. Usually, the obliquely stretched film develops a slow axis that is neither parallel nor perpendicular to the width direction. Therefore, in the first optically anisotropic layer as the obliquely stretched film, a slow axis forming a predetermined angle with respect to the width direction can be easily expressed. Therefore, the first optically anisotropic layer as the obliquely stretched film is laminated with the polarizing film having the transmission axis in the width direction and the second optically anisotropic layer by roll-to-roll to easily manufacture a circularly polarizing plate. it can.
　第１樹脂フィルムの延伸倍率は、好ましくは１．１倍以上、より好ましくは１．３倍以上、特に好ましくは１．５倍以上であり、好ましくは４倍以下、より好ましくは３倍以下、特に好ましくは２．５倍以下である。２以上の方向へ延伸を行う場合、各方向への延伸倍率の積が、前記の範囲に収まることが望ましい。延伸倍率を前記範囲に収めることにより、所望の光学特性を有する第１光学異方性層を得やすい。 The stretch ratio of the first resin film is preferably 1.1 times or more, more preferably 1.3 times or more, particularly preferably 1.5 times or more, preferably 4 times or less, more preferably 3 times or less, It is particularly preferably 2.5 times or less. When stretching is performed in two or more directions, it is desirable that the product of the stretching ratios in each direction be within the above range. By setting the stretching ratio within the above range, it is easy to obtain the first optically anisotropic layer having desired optical characteristics.
　第１樹脂フィルムの延伸温度は、好ましくはＴｇ１℃以上、より好ましくは「Ｔｇ１＋２℃」以上、特に好ましくは「Ｔｇ１＋５℃」以上であり、好ましくは「Ｔｇ１＋４０℃」以下、より好ましくは「Ｔｇ１＋３５℃」以下、特に好ましくは「Ｔｇ１＋３０℃」以下である。ここでＴｇ１とは、正の固有複屈折値を有する樹脂のガラス転移温度を表す。延伸温度を前記の範囲にすることにより、第１樹脂フィルムに含まれる分子を確実に配向させることができるので、所望の光学特性を有する第１光学異方性層を容易に得ることができる。 The stretching temperature of the first resin film is preferably Tg 1 °C or higher, more preferably "Tg 1 +2 °C" or higher, particularly preferably "Tg 1 +5 °C" or higher, preferably "Tg 1 +40 °C" or lower, It is more preferably "Tg 1 +35°C" or lower, and particularly preferably "Tg 1 +30°C" or lower. Here, Tg 1 represents the glass transition temperature of the resin having a positive intrinsic birefringence value. By setting the stretching temperature within the above range, the molecules contained in the first resin film can be reliably oriented, and thus the first optically anisotropic layer having desired optical characteristics can be easily obtained.
　工程１（第１光学異方性層の製造方法）では、前述した工程以外に任意の工程を更に行ってもよい。例えば、長尺の第１樹脂フィルムを用いて長尺の第１光学異方性層を製造した場合には、当該第１光学異方性層を所望の形状に切り出すトリミング工程を行ってもよい。トリミング工程を行うことにより、所望の形状を有する枚葉の第１光学異方性層が得られる。また、例えば、第１光学異方性層に保護層を設ける工程を行なってもよい。 In step 1 (method for producing the first optically anisotropic layer), any step other than the steps described above may be further performed. For example, when the elongated first optically anisotropic layer is manufactured using the elongated first resin film, a trimming step of cutting out the first optically anisotropic layer into a desired shape may be performed. .. By performing the trimming process, a single-wafer first optically anisotropic layer having a desired shape is obtained. Further, for example, a step of providing a protective layer on the first optically anisotropic layer may be performed.
　［１－６－２．工程２］
　工程２は、負の固有複屈折値を有する樹脂を含む第２樹脂フィルムを延伸して第２光学異方性層を得る工程である。 [1-6-2. Process 2]
Step 2 is a step of stretching a second resin film containing a resin having a negative intrinsic birefringence value to obtain a second optically anisotropic layer.
　工程２で用いる負の固有複屈折値を有する樹脂を含む第２樹脂フィルムは、溶融成形法又は溶液流延法によって製造でき、溶融成形法が好ましい。また、溶融成形法の中でも、押出成形法、インフレーション成形法又はプレス成形法が好ましく、押出成形法が特に好ましい。 The second resin film containing a resin having a negative intrinsic birefringence value used in step 2 can be produced by a melt molding method or a solution casting method, and the melt molding method is preferable. Further, among the melt molding methods, the extrusion molding method, the inflation molding method or the press molding method is preferable, and the extrusion molding method is particularly preferable.
　第２樹脂フィルムが例えば負の固有複屈折値を有する樹脂からなる層と保護層とを備える複層フィルムである場合、共押出Ｔダイ法、共押出インフレーション法、共押出ラミネーション法等の共押出成形方法；ドライラミネーション等のフィルムラミネーション成形方法；ある層に対してそれ以外の層を構成する樹脂溶液をコーティングするようなコーティング成形方法などの方法を用いうる。中でも、製造効率が良く、第２光学異方性層に溶媒などの揮発性成分を残留させないという観点から、共押出成形方法が好ましい。共押出成形法の中でも、共押出Ｔダイ法が好ましい。さらに共押出Ｔダイ法にはフィードブロック方式、マルチマニホールド方式が挙げられるが、層の厚さのばらつきを少なくできる点でマルチマニホールド方式がさらに好ましい。 When the second resin film is, for example, a multilayer film including a layer made of a resin having a negative intrinsic birefringence value and a protective layer, coextrusion T-die method, coextrusion inflation method, coextrusion lamination method, or other coextrusion method. A method such as a molding method; a film lamination method such as dry lamination; a coating molding method in which a certain layer is coated with a resin solution forming the other layer can be used. Among them, the coextrusion molding method is preferable from the viewpoint of good production efficiency and preventing volatile components such as a solvent from remaining in the second optically anisotropic layer. Among the coextrusion molding methods, the coextrusion T-die method is preferable. Further, the co-extrusion T-die method includes a feed block method and a multi-manifold method, but the multi-manifold method is more preferable in that the variation in layer thickness can be reduced.
　通常、第２樹脂フィルムは、長尺の樹脂フィルムとして得られる。第２樹脂フィルムを長尺の樹脂フィルムとして用意することにより、第２光学異方性層を製造する場合に各工程の一部または全部をインラインで行うことが可能であるので、製造を簡便且つ効率的に行なうことできる。 Normally, the second resin film is obtained as a long resin film. By preparing the second resin film as a long resin film, some or all of the steps can be performed in-line when the second optically anisotropic layer is manufactured, so that the manufacturing is simple and easy. It can be done efficiently.
　第２樹脂フィルムの延伸方法は、延伸により発現させたい光学特性に応じて適切なものを任意に採用しうる。本実施形態において、第２樹脂フィルムの延伸方法としては特に限定はないが、二方向延伸（二軸延伸）が好ましい。第２樹脂フィルムを二方向延伸することにより負の固有複屈折率値を有する樹脂を含む層の二軸性を高めることができ、ＮＺ２を０より小さくすることができる。二方向延伸には、例えば、遂次二軸延伸および同時二軸延伸が含まれる。 As a stretching method for the second resin film, an appropriate stretching method can be arbitrarily adopted according to the optical characteristics to be exhibited by stretching. In the present embodiment, the method for stretching the second resin film is not particularly limited, but bidirectional stretching (biaxial stretching) is preferable. By bidirectionally stretching the second resin film, the biaxiality of the layer containing the resin having a negative intrinsic birefringence value can be enhanced, and NZ2 can be made smaller than 0. Bidirectional stretching includes, for example, sequential biaxial stretching and simultaneous biaxial stretching.
　第２樹脂フィルムの延伸方向は、特に限定されない。第２樹脂フィルムの延伸は、斜め方向への延伸を含むことが好ましい。斜め方向への延伸を含む製造方法により、斜め延伸フィルムとしての第２光学異方性層を得ることができる。通常、斜め延伸フィルムには、その幅手方向に平行でなく垂直でもない遅相軸が発現する。よって、この斜め延伸フィルムとしての第２光学異方性層には、幅手方向に対して所定の角度をなす遅相軸を容易に発現させることができる。したがって、斜め延伸フィルムとしての第２光学異方性層は、幅手方向に透過軸を有する偏光フィルム及び第１光学異方性層とロールトゥロールで貼り合わせて、円偏光板を容易に製造できる。 The stretching direction of the second resin film is not particularly limited. Stretching of the second resin film preferably includes stretching in an oblique direction. The second optically anisotropic layer as an obliquely stretched film can be obtained by a production method including stretching in an oblique direction. Usually, the obliquely stretched film develops a slow axis that is neither parallel nor perpendicular to the width direction. Therefore, in the second optically anisotropic layer as the obliquely stretched film, a slow axis forming a predetermined angle with respect to the width direction can be easily expressed. Therefore, the second optically anisotropic layer as the obliquely stretched film is laminated with the polarizing film having the transmission axis in the width direction and the first optically anisotropic layer by roll-to-roll to easily manufacture the circularly polarizing plate. it can.
　第２樹脂フィルムの延伸倍率は、好ましくは１．１倍以上、より好ましくは１．２倍以上、特に好ましくは１．３倍以上であり、好ましくは４倍以下、より好ましくは３倍以下、特に好ましくは２．５倍以下である。２以上の方向へ延伸を行う場合、各方向への延伸倍率の積が、前記の範囲に収まることが望ましい。延伸倍率を前記範囲に収めることにより、所望の光学特性を有する第２光学異方性層を得やすい。 The draw ratio of the second resin film is preferably 1.1 times or more, more preferably 1.2 times or more, particularly preferably 1.3 times or more, preferably 4 times or less, more preferably 3 times or less, It is particularly preferably 2.5 times or less. When stretching is performed in two or more directions, it is desirable that the product of the stretching ratios in each direction be within the above range. By setting the stretching ratio within the above range, it is easy to obtain the second optically anisotropic layer having desired optical characteristics.
　第２樹脂フィルムの延伸温度は、好ましくはＴｇ２℃以上、より好ましくは「Ｔｇ２＋２℃」以上、特に好ましくは「Ｔｇ２＋５℃」以上であり、好ましくは「Ｔｇ２＋４０℃」以下、より好ましくは「Ｔｇ２＋３５℃」以下、特に好ましくは「Ｔｇ２＋３０℃」以下である。ここでＴｇ２とは、負の固有複屈折値を有する樹脂のガラス転移温度を表す。延伸温度を前記の範囲にすることにより、第２樹脂フィルムに含まれる分子を確実に配向させることができるので、所望の光学特性を有する第２光学異方性層を容易に得ることができる。 The stretching temperature of the second resin film is preferably Tg 2 °C or higher, more preferably "Tg 2 +2 °C" or higher, particularly preferably "Tg 2 +5 °C" or higher, preferably "Tg 2 +40 °C" or lower, It is more preferably "Tg 2 +35°C" or lower, and particularly preferably "Tg 2 +30°C" or lower. Here, Tg 2 represents the glass transition temperature of a resin having a negative intrinsic birefringence value. By setting the stretching temperature in the above range, the molecules contained in the second resin film can be reliably oriented, so that the second optically anisotropic layer having desired optical characteristics can be easily obtained.
　工程２は工程１と同時に行ってもよいし、工程１よりも先に行ってもよい。また、工程２（第２光学異方性層の製造方法）においては、前述した工程以外に任意の工程を更に行ってもよい。例えば、工程１（第１光学異方性層の製造方法）で例示した任意の工程と同じ工程を行ってもよい。 Step 2 may be performed at the same time as step 1, or may be performed before step 1. Further, in the step 2 (method for producing the second optically anisotropic layer), any step may be further performed in addition to the steps described above. For example, the same steps as the arbitrary steps exemplified in Step 1 (method for producing first optically anisotropic layer) may be performed.
　［１－６－３．工程３］
　工程３は、第１光学異方性層と第２光学異方性層とを重ねる工程である。
　工程３においては、第１光学異方性層と第２光学異方性層とを、第１光学異方性層の遅相軸と、第２光学異方性層の遅相軸とのなす角が８５°～９５°となるように重ねる。つまり、第１光学異方性層の遅相軸と第２光学異方性層の遅相軸とが直交するように重ねる。
　第１光学異方性層の遅相軸と第２光学異方性層の遅相軸とのなす角は、好ましくは９０°であるが、例えば±５°、±３°、±２°又は±１°の範囲内での誤差を含んでいてもよい。よって、第１光学異方性層の遅相軸と第２光学異方性層の遅相軸とのなす角は、例えば、８５°～９５°、８７°～９３°、８８°～９２°、又は、８９°～９１°、でありうる。このような態様とすることにより、得られた光学異方性積層体を備える円偏光板を、表示装置に用いることにより、外光の反射を抑制でき、表示面を傾斜方向から見た場合に、外光の反射を抑制して、色付きを効果的に抑制できる。 [1-6-3. Process 3]
Step 3 is a step of stacking the first optically anisotropic layer and the second optically anisotropic layer.
In step 3, the first optically anisotropic layer and the second optically anisotropic layer are formed by the slow axis of the first optically anisotropic layer and the slow axis of the second optically anisotropic layer. Stack so that the angle is 85° to 95°. That is, the slow axis of the first optically anisotropic layer and the slow axis of the second optically anisotropic layer are stacked so as to be orthogonal to each other.
The angle formed by the slow axis of the first optically anisotropic layer and the slow axis of the second optically anisotropic layer is preferably 90°, for example ±5°, ±3°, ±2° or An error within a range of ±1° may be included. Therefore, the angle formed by the slow axis of the first optically anisotropic layer and the slow axis of the second optically anisotropic layer is, for example, 85° to 95°, 87° to 93°, 88° to 92°. , Or 89° to 91°. By adopting such a mode, by using the circularly polarizing plate provided with the obtained optically anisotropic laminate in a display device, reflection of external light can be suppressed, and when the display surface is viewed from the tilt direction. By suppressing the reflection of external light, coloring can be effectively suppressed.
　［１－６－４．貼合工程（任意工程）］
　第１光学異方性層と、第２光学異方性層とを重ねた後に、当該２つの層を貼り合せることにより光学異方性積層体を製造しうる。貼り合わせには、適切な接着剤を用いうる。接着剤としては、例えば、下記偏光板の製造に用いうる接着剤と同様の接着剤を用いうる。この貼合工程は任意の工程である。 [1-6-4. Laminating process (optional process)]
An optical anisotropic laminate can be manufactured by stacking the first optical anisotropic layer and the second optical anisotropic layer and then bonding the two layers together. A suitable adhesive may be used for bonding. As the adhesive, for example, an adhesive similar to the adhesive that can be used for manufacturing the polarizing plate described below can be used. This laminating step is an optional step.
　［２．円偏光板］
　本実施形態の円偏光板５００は、直線偏光子１３０と、上記の光学異方性積層体１００と、を備える。本実施形態の円偏光板５００を、画像表示装置の表示面に設けることにより、外光の反射を抑制できる。本実施形態の光学異方性積層体１００を備える本実施形態の円偏光板５００によれば、表示面を傾斜方向から見た場合に、外光の反射を抑制して、色付きを効果的に抑制できる。 [2. Circular polarizer]
The circularly polarizing plate 500 of the present embodiment includes the linear polarizer 130 and the above-mentioned optically anisotropic laminate 100. By providing the circularly polarizing plate 500 of this embodiment on the display surface of the image display device, reflection of external light can be suppressed. According to the circularly polarizing plate 500 of the present embodiment including the optically anisotropic layered product 100 of the present embodiment, when the display surface is viewed from the tilt direction, reflection of external light is suppressed and coloring is effectively performed. Can be suppressed.
　本実施形態の円偏光板５００は、図１に示すように、直線偏光子１３０、第１光学異方性層１１０、及び前記第２光学異方性層１２０を、この順で備える。 As shown in FIG. 1, the circularly polarizing plate 500 of the present embodiment includes a linear polarizer 130, a first optical anisotropic layer 110, and the second optical anisotropic layer 120 in this order.
　図１において、１３２は直線偏光子１３０の透過軸１３１を第１光学異方性層１１０に投影した軸であり、１３３は直線偏光子１３０の透過軸１３１を第２光学異方性層１２０に投影した軸である。角度θＡ１は、直線偏光子１３０の透過軸１３１に対して第１光学異方性層１１０の遅相軸１１１が時計回りになす角度である。角度θＢ１は、直線偏光子１３０の透過軸１３１に対して第２光学異方性層１２０の遅相軸１２１が時計回りになす角度である。 In FIG. 1, 132 is an axis obtained by projecting the transmission axis 131 of the linear polarizer 130 onto the first optical anisotropic layer 110, and 133 is the transmission axis 131 of the linear polarizer 130 to the second optical anisotropic layer 120. The projected axis. The angle θA1 is an angle formed by the slow axis 111 of the first optically anisotropic layer 110 clockwise with respect to the transmission axis 131 of the linear polarizer 130. The angle θB1 is an angle formed by the slow axis 121 of the second optically anisotropic layer 120 clockwise with respect to the transmission axis 131 of the linear polarizer 130.
　本実施形態の円偏光板５００において、直線偏光子１３０の透過軸１３１と、第１光学異方性層１１０の遅相軸１１１とのなす角度θＡ１は４５°に近いのが好ましい。角度θＡ１は、具体的には、好ましくは４５°±５°（即ち、好ましくは４０°～５０°）、より好ましくは４５°±４°（即ち、より好ましくは４１°～４９°）、特に好ましくは４５°±３°（即ち、特に好ましくは４２°～４８°）である。
　なお、ここでは直線偏光子１３０の透過軸１３１に対して第１光学異方性層１１０の遅相軸１１１が時計回りに前記の角度θＡ１をなす例を示したが、直線偏光子１３０の透過軸１３１に対して第１光学異方性層１１０の遅相軸１１１が前記の角度θＡ１をなす向きは、時計回りでもよく、反時計回りでもよい。さらに、直線偏光子１３０の透過軸１３１に対して第２光学異方性層１２０の遅相軸１２１が前記の角度θＢ１をなす向きは、時計回りでもよく、反時計回りでもよい。 In the circularly polarizing plate 500 of this embodiment, the angle θA1 formed by the transmission axis 131 of the linear polarizer 130 and the slow axis 111 of the first optically anisotropic layer 110 is preferably close to 45°. The angle θA1 is specifically preferably 45°±5° (ie, preferably 40°-50°), more preferably 45°±4° (ie, more preferably 41°-49°), particularly It is preferably 45°±3° (that is, particularly preferably 42° to 48°).
Although the slow axis 111 of the first optical anisotropic layer 110 makes the angle θA1 clockwise with respect to the transmission axis 131 of the linear polarizer 130, the transmission of the linear polarizer 130 is shown. The direction in which the slow axis 111 of the first optical anisotropic layer 110 forms the angle θA1 with respect to the axis 131 may be clockwise or counterclockwise. Furthermore, the direction in which the slow axis 121 of the second optical anisotropic layer 120 forms the angle θB1 with respect to the transmission axis 131 of the linear polarizer 130 may be clockwise or counterclockwise.
　又は、円偏光板５００において、直線偏光子１３０の吸収軸（図示せず）と、第１光学異方性層１１０の遅相軸１１１とのなす角は４５°に近いのが好ましい。直線偏光子１３０の吸収軸と第１光学異方性層１１０の遅相軸１１１とのなす角は、具体的には、好ましくは４５°±５°（即ち、好ましくは４０°～５０°）、より好ましくは４５°±４°（即ち、より好ましくは４１°～４９°）、特に好ましくは４５°±３°（即ち、特に好ましくは４２°～４８°）である。直線偏光子１３０の吸収軸に対して第１光学異方性層１１０の遅相軸１１１が前記の角をなす向きは、時計回りでもよく、反時計回りでもよい。 Alternatively, in the circularly polarizing plate 500, the angle between the absorption axis (not shown) of the linear polarizer 130 and the slow axis 111 of the first optically anisotropic layer 110 is preferably close to 45°. The angle between the absorption axis of the linear polarizer 130 and the slow axis 111 of the first optical anisotropic layer 110 is specifically 45°±5° (that is, preferably 40°-50°). More preferably 45°±4° (ie, more preferably 41° to 49°), particularly preferably 45°±3° (ie, particularly preferably 42° to 48°). The direction in which the slow axis 111 of the first optical anisotropic layer 110 forms the angle with respect to the absorption axis of the linear polarizer 130 may be clockwise or counterclockwise.
　直線偏光子１３０としては、任意の直線偏光子を用いうる。直線偏光子の例としては、ポリビニルアルコールフィルムにヨウ素又は二色性染料を吸着させた後、ホウ酸浴中で一方向延伸することによって得られるフィルム；ポリビニルアルコールフィルムにヨウ素又は二色性染料を吸着させ延伸しさらに分子鎖中のポリビニルアルコール単位の一部をポリビニレン単位に変性することによって得られるフィルム；が挙げられる。また、直線偏光子の他の例としては、グリッド偏光子、多層偏光子、などの、偏光を反射光と透過光に分離する機能を有する偏光子が挙げられる。これらのうち、直線偏光子１３０としては、ポリビニルアルコールを含有する偏光子が好ましい。 Any linear polarizer can be used as the linear polarizer 130. As an example of the linear polarizer, a film obtained by adsorbing iodine or a dichroic dye on a polyvinyl alcohol film and then unidirectionally stretching it in a boric acid bath; A film obtained by adsorbing and stretching, and further modifying a part of polyvinyl alcohol units in the molecular chain into polyvinylene units. Other examples of the linear polarizer include a polarizer having a function of separating polarized light into reflected light and transmitted light, such as a grid polarizer and a multilayer polarizer. Of these, the linear polarizer 130 is preferably a polarizer containing polyvinyl alcohol.
　直線偏光子１３０に自然光を入射させると、一方の偏光だけが透過する。この直線偏光子１３０の偏光度は特に限定されないが、好ましくは９８％以上、より好ましくは９９％以上である。
　また、直線偏光子１３０の厚みは、好ましくは５μｍ～８０μｍである。 When natural light is incident on the linear polarizer 130, only one polarized light is transmitted. The degree of polarization of the linear polarizer 130 is not particularly limited, but is preferably 98% or more, more preferably 99% or more.
The thickness of the linear polarizer 130 is preferably 5 μm to 80 μm.
　円偏光板は、更に、直線偏光子と光学異方性積層体とを貼り合わせるための、接着層を備えていてもよい。接着層としては、粘着性の接着剤からなる粘着層を用いてもよく、硬化性接着剤を硬化させてなる層を用いてもよい。硬化性接着剤としては、熱硬化性接着剤を用いてもよいが、光硬化性接着剤を用いることが好ましい。光硬化性接着剤としては、重合体又は反応性の単量体を含んだものを用いうる。また、接着剤は、必要に応じて溶媒、光重合開始剤、その他の添加剤などを含みうる。 The circularly polarizing plate may further include an adhesive layer for bonding the linear polarizer and the optically anisotropic laminate. As the adhesive layer, an adhesive layer made of an adhesive adhesive may be used, or a layer formed by curing a curable adhesive may be used. A thermosetting adhesive may be used as the curable adhesive, but a photocurable adhesive is preferably used. As the photocurable adhesive, one containing a polymer or a reactive monomer can be used. Further, the adhesive may contain a solvent, a photopolymerization initiator, other additives, etc., if necessary.
　光硬化性接着剤は、可視光線、紫外線、赤外線などの光を照射すると硬化しうる接着剤である。中でも、操作が簡便なことから、紫外線で硬化しうる接着剤が好ましい。 Photo-curable adhesives are adhesives that can be cured by irradiation with light such as visible light, ultraviolet rays, and infrared rays. Among them, an adhesive that can be cured by ultraviolet rays is preferable because it is easy to operate.
　接着層の厚みは、好ましくは０．５μｍ以上、より好ましくは１μｍ以上であり、好ましくは３０μｍ以下、より好ましくは２０μｍ以下、さらに好ましくは１０μｍ以下である。接着層の厚みを前記範囲内とすることにより、光学異方性層の光学的性質を損ねずに、良好な接着を達成しうる。 The thickness of the adhesive layer is preferably 0.5 μm or more, more preferably 1 μm or more, preferably 30 μm or less, more preferably 20 μm or less, still more preferably 10 μm or less. By setting the thickness of the adhesive layer within the above range, good adhesion can be achieved without impairing the optical properties of the optically anisotropic layer.
　上述した円偏光板は、更に、任意の層を含みうる。任意の層としては、例えば、偏光子保護フィルム層、耐衝撃性ポリメタクリレート樹脂層などのハードコート層、フィルムの滑り性を良くするマット層、反射抑制層、防汚層、帯電抑制層等が挙げられる。これらの任意の層は、１層だけを設けてもよく、２層以上を設けてもよい。 The above-mentioned circularly polarizing plate may further include an optional layer. Examples of the optional layer include a polarizer protective film layer, a hard coat layer such as an impact-resistant polymethacrylate resin layer, a mat layer that improves the slipperiness of the film, a reflection suppressing layer, an antifouling layer, and an antistatic layer. Can be mentioned. These optional layers may be provided in only one layer or in two or more layers.
　［３．画像表示装置］
　本実施形態の円偏光板は画像表示装置に用いうる。本実施形態の画像表示装置は、本実施形態の円偏光板と、有機エレクトロルミネッセンス素子（以下、適宜「有機ＥＬ素子」ということがある。）と、を備える。この画像表示装置は、通常、直線偏光子、光学異方性積層体及び有機ＥＬ素子を、この順に備える。 [3. Image display device]
The circularly polarizing plate of this embodiment can be used for an image display device. The image display device of the present embodiment includes the circularly polarizing plate of the present embodiment and an organic electroluminescence element (hereinafter, also referred to as “organic EL element” as appropriate). This image display device usually comprises a linear polarizer, an optically anisotropic laminate and an organic EL element in this order.
　また、画像表示装置は、直線偏光子、第１光学異方性層、第２光学異方性層及び有機ＥＬ素子をこの順に備えうる。 Further, the image display device may include a linear polarizer, a first optical anisotropic layer, a second optical anisotropic layer and an organic EL element in this order.
　有機ＥＬ素子は、透明電極層、発光層及び電極層をこの順に備え、透明電極層及び電極層から電圧を印加されることにより発光層が光を生じうる。有機発光層を構成する材料の例としては、ポリパラフェニレンビニレン系、ポリフルオレン系、及びポリビニルカルバゾール系の材料を挙げることができる。また、発光層は、複数の発光色が異なる層の積層体、あるいはある色素の層に異なる色素がドーピングされた混合層を有していてもよい。さらに、有機ＥＬ素子は、正孔注入層、正孔輸送層、電子注入層、電子輸送層、等電位面形成層、電荷発生層等の機能層を備えていてもよい。 The organic EL element includes a transparent electrode layer, a light emitting layer, and an electrode layer in this order, and the light emitting layer may generate light when a voltage is applied from the transparent electrode layer and the electrode layer. Examples of materials forming the organic light emitting layer include polyparaphenylene vinylene-based materials, polyfluorene-based materials, and polyvinylcarbazole-based materials. Further, the light emitting layer may have a laminated body of a plurality of layers having different emission colors or a mixed layer in which a certain dye layer is doped with different dyes. Furthermore, the organic EL element may include functional layers such as a hole injection layer, a hole transport layer, an electron injection layer, an electron transport layer, an equipotential surface forming layer, and a charge generation layer.
　前記の画像表示装置は、表示面における外光の反射を抑制できる。具体的には、装置外部から入射した光は、その一部の直線偏光のみが直線偏光子を通過し、次にそれが光学異方性積層体を通過することにより、円偏光となる。円偏光は、表示装置内の光を反射する構成要素（有機ＥＬ素子中の反射電極（図示せず）等）により反射され、再び光学異方性積層体を通過することにより、入射した直線偏光の振動方向と直交する振動方向を有する直線偏光となり、直線偏光子を通過しなくなる。ここで、直線偏光の振動方向とは、直線偏光の電場の振動方向を意味する。これにより、反射抑制の機能が達成される。 The above image display device can suppress reflection of external light on the display surface. Specifically, the light incident from the outside of the device becomes circularly polarized light because only part of the linearly polarized light passes through the linear polarizer and then it passes through the optically anisotropic laminate. The circularly polarized light is reflected by a constituent element (a reflective electrode (not shown) in the organic EL element, etc.) that reflects light in the display device, and again passes through the optically anisotropic laminated body to make incident linearly polarized light. The linearly polarized light has a vibration direction orthogonal to the vibration direction of, and does not pass through the linear polarizer. Here, the direction of vibration of linearly polarized light means the direction of vibration of the electric field of linearly polarized light. Thereby, the function of suppressing reflection is achieved.
　さらに、画像表示装置は、光学異方性積層体が所定の光学特性を有するので、前記の反射抑制の機能を、表示面の正面方向だけでなく、傾斜方向においても発揮できる。そして、これにより、反射光による表示面の色付きを抑制できる。したがって、画像表示装置は、表示面の正面方向及び傾斜方向の両方において、外光の反射を効果的に抑制して、色付きを抑制することが可能である。 Further, in the image display device, since the optically anisotropic laminate has predetermined optical characteristics, the reflection suppressing function can be exerted not only in the front direction of the display surface but also in the tilt direction. And thereby, the coloring of the display surface due to the reflected light can be suppressed. Therefore, the image display device can effectively suppress reflection of external light and suppress coloring in both the front direction and the tilt direction of the display surface.
　前記の色付きの程度は、表示面を傾斜方向から観察して測定される色度と、反射の無い黒色の表示面の色度との色差ΔＥ＊ａｂによって、評価しうる。前記の色度は、表示面で反射した光のスペクトルを測定し、このスペクトルから、人間の目に対応する分光感度（等色関数）を乗じて三刺激値Ｘ、Ｙ及びＺを求め、色度（ａ＊，ｂ＊，Ｌ＊）を算出することにより求めうる。また、前記の色差ΔＥ＊ａｂは、外光によって表示面が照らされていない場合の色度（ａ０＊，ｂ０＊，Ｌ０＊）、及び、外光によって照らされている場合の色度（ａ１＊，ｂ１＊，Ｌ１＊）から、下記の式（Ｘ）から求めうる。 The degree of coloring can be evaluated by the color difference ΔE * ab between the chromaticity measured by observing the display surface from the tilt direction and the chromaticity of the black display surface without reflection. The chromaticity is obtained by measuring the spectrum of the light reflected on the display surface and multiplying the spectral sensitivity (color matching function) corresponding to the human eye from this spectrum to obtain the tristimulus values X, Y, and Z. It can be obtained by calculating the degree (a * , b * , L * ). The color difference ΔE * ab is the chromaticity (a0 * , b0 * , L0 * ) when the display surface is not illuminated by external light and the chromaticity (a1 when illuminated by external light. * , b1 * , L1 * ) can be obtained from the following formula (X).
Figure JPOXMLDOC01-appb-M000003
Figure JPOXMLDOC01-appb-M000003
　また、一般に、反射光による表示面の色付きは、観察方向の方位角によって異なりうる。そのため、表示面の傾斜方向から観察した場合、観察方向の方位角によって、測定される色度は異なりうるので、色差ΔＥ＊ａｂも異なりうる。そこで、前記のように表示面の傾斜方向から観察したときの色付きの程度を評価する場合には、複数の方位角方向から観察して得られる色差ΔＥ＊ａｂの平均値によって、色付きの評価を行うことが好ましい。具体的には、方位角方向に５°刻みで、方位角φ（図３参照。）が０°以上３６０°未満の範囲で、色差ΔＥ＊ａｂの測定を行い、測定された色差ΔＥ＊ａｂの平均値（平均色差）によって、色付きの程度を評価する。前記の平均色差が小さいほど、表示面の傾斜方向から観察した場合の表示面の色付きが小さいことを表す。 Further, in general, the coloring of the display surface due to the reflected light may differ depending on the azimuth angle in the viewing direction. Therefore, when observed from the tilt direction of the display surface, the measured chromaticity may differ depending on the azimuth angle of the observation direction, and thus the color difference ΔE * ab may also differ. Therefore, as described above, when evaluating the degree of coloring when observed from the tilt direction of the display surface, the evaluation of coloring is performed by the average value of the color difference ΔE * ab obtained by observing from a plurality of azimuth directions. It is preferable to carry out. Specifically, in 5 ° increments in azimuth, the azimuth angle phi (see FIG. 3.) Is in a range of less than 0 ° or 360 °, was measured for color difference Delta] E * ab, measured color difference Delta] E * ab The degree of coloring is evaluated by the average value (average color difference) of. The smaller the average color difference, the smaller the coloring of the display surface when observed from the tilt direction of the display surface.
　［実施形態２］
　以下、本発明の実施形態２に係る光学異方性積層体を備える円偏光板及び、当該円偏光板を備える画像表示装置について図２を参照しつつ、説明する。図２は、実施形態２に係る円偏光板６００を模式的に示す分解斜視図である。 [Embodiment 2]
Hereinafter, a circularly polarizing plate including the optically anisotropic laminate according to the second embodiment of the present invention and an image display device including the circularly polarizing plate will be described with reference to FIG. FIG. 2 is an exploded perspective view schematically showing the circularly polarizing plate 600 according to the second embodiment.
　本実施形態の光学異方性積層体２００は、第２光学異方性層１２０及び第１光学異方性層１１０の配置が実施形態１と相違すること以外は、実施形態１と同じに設けられている。以下において、実施形態１と同様の構成については、同じ符号を付し、重複した説明は省略する。 The optically anisotropic laminate 200 of the present embodiment is provided in the same manner as in the first embodiment except that the arrangement of the second optically anisotropic layer 120 and the first optically anisotropic layer 110 is different from that of the first embodiment. Has been. In the following, the same components as those in the first embodiment are designated by the same reference numerals, and the duplicated description will be omitted.
　本実施形態の円偏光板６００は、図２に示すように、直線偏光子１３０と、本実施形態の光学異方性積層体２００と、を備える。本実施形態の円偏光板６００は、図２に示すように、直線偏光子１３０、前記第２光学異方性層１２０及び第１光学異方性層１１０を、この順で備える。 As shown in FIG. 2, the circularly polarizing plate 600 of the present embodiment includes a linear polarizer 130 and the optically anisotropic laminated body 200 of the present embodiment. As shown in FIG. 2, the circularly polarizing plate 600 of the present embodiment includes a linear polarizer 130, the second optically anisotropic layer 120, and the first optically anisotropic layer 110 in this order.
　図２において、１３２は直線偏光子の透過軸を第１光学異方性層１１０に投影した軸であり、１３３は直線偏光子の透過軸を第２光学異方性層１２０に投影した軸である。角度θＡ２は、直線偏光子１３０の透過軸１３１に対して第１光学異方性層１１０の遅相軸１１１が時計回りになす角度である。角度θＢ２は、直線偏光子１３０の透過軸１３１に対して第２光学異方性層１２０の遅相軸１２１が時計回りになす角度である。角度θＡ２及び角度θＢ２は、それぞれ、実施形態１で説明した角度θＡ１及び角度θＢ１と同じ範囲にあることが好ましい。 In FIG. 2, 132 is an axis obtained by projecting the transmission axis of the linear polarizer onto the first optically anisotropic layer 110, and 133 is an axis obtained by projecting the transmission axis of the linear polarizer onto the second optically anisotropic layer 120. is there. The angle θA2 is an angle formed by the slow axis 111 of the first optically anisotropic layer 110 clockwise with respect to the transmission axis 131 of the linear polarizer 130. The angle θB2 is an angle formed by the slow axis 121 of the second optically anisotropic layer 120 clockwise with respect to the transmission axis 131 of the linear polarizer 130. The angles θA2 and θB2 are preferably in the same ranges as the angles θA1 and θB1 described in the first embodiment, respectively.
　本実施形態の円偏光板は画像表示装置に用いうる。画像表示装置は、通常、直線偏光子、光学異方性積層体及び有機ＥＬ素子を、この順に備える。よって、本実施形態の円偏光板を備える画像表示装置は、直線偏光子、第２光学異方性層、第１光学異方性層及び有機ＥＬ素子をこの順に備えうる。 The circularly polarizing plate of this embodiment can be used in an image display device. An image display device usually includes a linear polarizer, an optically anisotropic laminate and an organic EL element in this order. Therefore, the image display device including the circularly polarizing plate of the present embodiment may include the linear polarizer, the second optical anisotropic layer, the first optical anisotropic layer, and the organic EL element in this order.
　本実施形態においても、光学異方性積層体２００は、上記式（１）～式（４）を満たす光学特性を有し、かつ、第１光学異方性層１１０の遅相軸１１１と第２光学異方性層１２０の遅相軸１２１とのなす角度が８５°～９５°である。よって、このような光学異方性積層体２００を直線偏光子１３０と組み合わせて得られる円偏光板６００を画像表示装置に設けることにより、その画像表示装置の表示面を傾斜方向から見た場合に外光の反射を抑制して、色付きを効果的に抑制できる。 Also in this embodiment, the optically anisotropic laminate 200 has optical characteristics satisfying the above formulas (1) to (4), and has the slow axis 111 of the first optically anisotropic layer 110 and the first axis. 2 The angle formed by the slow axis 121 of the optically anisotropic layer 120 is 85° to 95°. Therefore, by providing the image display device with the circularly polarizing plate 600 obtained by combining such an optically anisotropic laminate 200 with the linear polarizer 130, when the display surface of the image display device is viewed from the tilt direction. Coloring can be effectively suppressed by suppressing reflection of external light.
　以下、実施例を示して本発明について具体的に説明する。ただし、本発明は以下に示す実施例に限定されるものではなく、本発明の請求の範囲及びその均等の範囲を逸脱しない範囲において任意に変更して実施しうる。
　以下の説明において、量を表す「％」及び「部」は、別に断らない限り、重量基準である。また、以下に説明する操作は、別に断らない限り、常温及び常圧の条件において行った。 Hereinafter, the present invention will be specifically described with reference to examples. However, the present invention is not limited to the examples described below, and may be implemented by being arbitrarily modified within the scope of the claims and equivalents thereof.
In the following description, “%” and “parts” representing amounts are by weight unless otherwise specified. In addition, the operations described below were performed at room temperature and atmospheric pressure unless otherwise specified.
　［評価方法］
　（位相差及びＮＺ係数の測定方法）
　位相差計（Ａｘｏｍｅｔｒｉｃｓ社製「ＡｘｏＳｃａｎ」）を用いて、評価対象（第１光学異方性層、第２光学異方性層、光学異方性積層体）の幅手方向に５０ｍｍ間隔の複数の地点で、位相差を測定した。これらの地点での測定値の平均値を計算し、この平均値を、当該測定対象の位相差とした。 [Evaluation method]
(Phase difference and NZ coefficient measuring method)
Using a retardation meter (“AxoScan” manufactured by Axometrics), a plurality of 50 mm intervals in the width direction of the evaluation target (first optically anisotropic layer, second optically anisotropic layer, optically anisotropic laminate) The phase difference was measured at the point. The average value of the measured values at these points was calculated, and this average value was used as the phase difference of the measurement target.
　第１光学異方性層については、波長４５０ｎｍ、波長５５０ｎｍ、波長５９０ｎｍ、及び波長６５０ｎｍにおける面内位相差Ｒｅ１（４５０）、Ｒｅ１（５５０）、Ｒｅ１（５９０）、Ｒｅ１（６５０）、波長５９０ｎｍにおける厚み方向の位相差Ｒｔｈ１（５９０）、並びに、遅相軸方向を測定した。また、第２光学異方性層については、波長４５０ｎｍ、波長５５０ｎｍ、波長５９０ｎｍ、及び波長６５０ｎｍにおける面内位相差Ｒｅ２（４５０）、Ｒｅ２（５５０）、Ｒｅ２（５９０）、Ｒｅ２（６５０）、波長５９０ｎｍにおける厚み方向の位相差Ｒｔｈ２（５９０）、並びに、遅相軸方向を測定した。得られた面内位相差を用いて、Ｒｅ１（４５０）／Ｒｅ１（５５０）及びＲｅ１（４５０）／Ｒｅ１（５５０）を算出した。また、得られた面内位相差及び厚み方向の位相差の比率から、ＮＺ係数（ＮＺ１、ＮＺ２）を算出した。 Regarding the first optically anisotropic layer, the in-plane retardations Re1(450), Re1(550), Re1(590), Re1(650), and wavelength 590 nm at wavelengths of 450 nm, 550 nm, 590 nm, and 650 nm are used. The retardation Rth1 (590) in the thickness direction and the slow axis direction were measured. Regarding the second optically anisotropic layer, the in-plane retardations Re2(450), Re2(550), Re2(590), Re2(650), and wavelength at wavelengths of 450 nm, 550 nm, 590 nm, and 650 nm are used. The retardation Rth2 (590) in the thickness direction at 590 nm and the slow axis direction were measured. Re1(450)/Re1(550) and Re1(450)/Re1(550) were calculated using the obtained in-plane retardation. Further, the NZ coefficient (NZ1, NZ2) was calculated from the obtained ratio of the in-plane retardation and the thickness direction retardation.
　また、光学異方性積層体の、波長４５０ｎｍ、波長５５０ｎｍ、及び波長６５０ｎｍにおける面内位相差Ｒｅ（４５０）、Ｒｅ（５５０）、Ｒｅ（６５０）は、第１光学異方性層及び第２光学異方性層の光学特性値から計算により求めた。 Further, the in-plane retardations Re(450), Re(550), and Re(650) at the wavelengths of 450 nm, 550 nm, and 650 nm of the optically anisotropic laminate are the first optically anisotropic layer and the second optically anisotropic layer. It was calculated from the optical characteristic values of the optically anisotropic layer.
　（シミュレーションによる色差の計算方法）
　シミュレーション用のソフトウェアとしてシンテック社製「ＬＣＤ　Ｍａｓｔｅｒ」を用いて、各実施例及び比較例で製造された円偏光板をモデル化し、下記の計算を行った。 (Calculation method of color difference)
Using "LCD Master" manufactured by Shintech Co., Ltd. as simulation software, the circularly polarizing plates manufactured in each of the examples and comparative examples were modeled, and the following calculations were performed.
　シミュレーション用のモデルでは、平面状の反射面を有するミラーの前記反射面に、第２光学異方性層、第１光学異方性層及び偏光フィルムを前記反射面側からこの順に有する円偏光板を設けた構成を設定した。第１光学異方性層及び第２光学異方性層としては、各実施例及び比較例で用いたものを設定した。また、偏光フィルムとしては、一般的に使用されている偏光度９９．９９％の偏光板を設定した。また、ミラーとして、入射した光を反射率１００％で鏡面反射しうる理想ミラーを設定した。 In the simulation model, a circularly polarizing plate having a second optically anisotropic layer, a first optically anisotropic layer and a polarizing film on the reflecting surface of a mirror having a planar reflecting surface in this order from the reflecting surface side. Was set up. As the first optically anisotropic layer and the second optically anisotropic layer, those used in each Example and Comparative Example were set. As the polarizing film, a generally used polarizing plate having a polarization degree of 99.99% was set. Further, as the mirror, an ideal mirror capable of specularly reflecting the incident light with a reflectance of 100% was set.
　図３は、実施例及び比較例でのシミュレーションにおいて、色空間座標の計算を行う際に設定した評価モデルの様子を模式的に示す斜視図である。
　図３に示すように、Ｄ６５光源（図示せず。）によって照らされたときに、円偏光板を設けられたミラーの反射面１０で観察される色空間座標を計算した。また、光源によって照らされていないときの色空間座標をａ０＊＝０，ｂ０＊＝０，Ｌ０＊＝０とした。そして、（ｉ）光源で照らされたときの色空間座標と、（ii）光源で照らされていないときの色空間座標とから、前述の式（Ｘ）を用いて、色差ΔＥ＊ａｂを求めた。 FIG. 3 is a perspective view schematically showing a state of the evaluation model set when the color space coordinates are calculated in the simulations of the example and the comparative example.
As shown in FIG. 3, the color space coordinates observed on the reflecting surface 10 of the mirror provided with the circularly polarizing plate were calculated when illuminated by a D65 light source (not shown). Further, the color space coordinates when not illuminated by the light source were set to a0 * =0, b0 * =0, L0 * =0. Then, from (i) the color space coordinates when illuminated by the light source and (ii) the color space coordinates when not illuminated by the light source, the color difference ΔE * ab is obtained using the above-mentioned formula (X). It was
　前記の色差ΔＥ＊ａｂの計算を、反射面１０に対する極角ρが０°の観察方向２０で行って、正面方向での色差ΔＥ＊ａｂを求めた。極角ρとは、反射面１０の法線方向１１に対してなす角を表す。 The calculation of the color difference ΔE * ab was performed in the observation direction 20 in which the polar angle ρ with respect to the reflecting surface 10 was 0°, and the color difference ΔE * ab in the front direction was obtained. The polar angle ρ represents an angle formed with respect to the normal direction 11 of the reflecting surface 10.
　また、前記の色差ΔＥ＊ａｂの計算を、反射面１０に対する極角ρが６０°の観察方向２０で行った。この極角ρ＝６０°での計算は、観察方向２０を方位角方向に、方位角φを０°以上３６０°未満の範囲で５°刻みに移動させて、複数行った。方位角φとは、反射面１０に平行な方向が、反射面１０に平行なある基準方向１２に対してなす角を表す。そして、計算された複数の観察方向２０での色差ΔＥ＊ａｂの平均を計算して、極角ρ＝６０°の傾斜方向での色差ΔＥ＊ａｂを得た。 Further, the calculation of the color difference ΔE * ab was performed in the observation direction 20 in which the polar angle ρ with respect to the reflecting surface 10 was 60°. The calculation at the polar angle ρ=60° was performed plural times by moving the observation direction 20 to the azimuth direction and moving the azimuth angle φ in the range of 0° to less than 360° in 5° steps. The azimuth angle φ represents an angle formed by a direction parallel to the reflecting surface 10 with respect to a certain reference direction 12 parallel to the reflecting surface 10. Then, the average of the calculated color differences ΔE * ab in the plurality of observation directions 20 was calculated to obtain the color difference ΔE * ab in the tilt direction of the polar angle ρ=60°.
　（正面方向における目視による円偏光板の評価方法）
　ミラーを備える画像表示装置として、Ａｐｐｌｅ社の「ＡｐｐｌｅＷａｔｃｈ」（登録商標）を用意した。この画像表示装置のミラーに貼合されていた偏光板を剥離し、ミラーを露出させた。そのミラーの表面と、評価対象の円偏光板の第２光学異方性層の面とを粘着層（日東電工製「ＣＳ９６２１」）を介して貼り合せた。 (Evaluation method of circularly polarizing plate by visual observation in the front direction)
As an image display device provided with a mirror, “AppleWatch” (registered trademark) from Apple Inc. was prepared. The polarizing plate attached to the mirror of this image display device was peeled off to expose the mirror. The surface of the mirror and the surface of the second optically anisotropic layer of the circularly polarizing plate to be evaluated were attached via an adhesive layer (“CS9621” manufactured by Nitto Denko).
　晴れた日に日光で円偏光板を照らした状態で、ミラー上の円偏光板を目視で観察した。観察は、円偏光板の、極角０°、方位角０°の正面方向で行った。観察の結果、有彩色が視認された場合に「Ｂ」と判定し、有彩色が視認されなかった場合に「Ａ」と判定した。 On a sunny day, the circularly polarizing plate on the mirror was visually observed while the circularly polarizing plate was illuminated by sunlight. The observation was performed in the front direction of the circularly polarizing plate at a polar angle of 0° and an azimuth angle of 0°. As a result of the observation, it was determined as "B" when the chromatic color was visually recognized, and was determined as "A" when the chromatic color was not visually recognized.
　（傾斜方向における目視による円偏光板の評価方法）
　ミラーを備える画像表示装置として、Ａｐｐｌｅ社の「ＡｐｐｌｅＷａｔｃｈ」（登録商標）を用意した。この画像表示装置のミラーに貼合されていた偏光板を剥離し、ミラーを露出させた。そのミラーの表面と、評価対象の円偏光板の第２光学異方性層の面とを粘着層（日東電工製「ＣＳ９６２１」）を介して貼り合せた。
　晴れた日に日光で円偏光板を照らした状態で、ミラー上の円偏光板を目視で観察した。観察は、円偏光板の極角６０°、方位角０°～３６０°の傾斜方向で行った。観察の結果、反射輝度及び色付きの優劣を総合的に判定して、実施例及び比較例を順位づけした。そして、順位づけられた実施例及び比較例に、その順位に相当する点数（１位８点、２位７点、３位６点、４位５点、５位４点、６位３点、７位２点、８位１点）を与えた。 (Visual evaluation method of circularly polarizing plate in the tilt direction)
As an image display device provided with a mirror, “AppleWatch” (registered trademark) from Apple Inc. was prepared. The polarizing plate attached to the mirror of this image display device was peeled off to expose the mirror. The surface of the mirror and the surface of the second optically anisotropic layer of the circularly polarizing plate to be evaluated were attached via an adhesive layer (“CS9621” manufactured by Nitto Denko).
The circularly polarizing plate on the mirror was visually observed while the circularly polarizing plate was illuminated by sunlight on a sunny day. The observation was performed in the tilt direction of the circularly polarizing plate having a polar angle of 60° and an azimuth angle of 0° to 360°. As a result of the observation, the superiority and inferiority of the reflection brightness and the coloring were comprehensively determined and the examples and the comparative examples were ranked. Then, in the ranked examples and comparative examples, points corresponding to the ranking (1st place 8 points, 2nd place 7 points, 3rd place 6 points, 4th place 5 points, 5th place 4 points, 6th place 3 points, 7th place 2 points and 8th place 1 point) were given.
　前記の観察を多人数が行い、各実施例及び比較例について、与えられた点数の合計点を求めた。実施例及び比較例を前記の合計点の順に並べ、その合計点のレンジを５等分して、上位グループからＡ、Ｂ、Ｃ、Ｄ及びＥの順に評価した。 A large number of people conducted the above observations, and calculated the total points given for each Example and Comparative Example. Examples and comparative examples were arranged in the order of the above total points, and the range of the total points was divided into 5 equal parts and evaluated in the order of A, B, C, D and E from the upper group.
　［製造例］
　［製造例１：偏光フィルム（直線偏光子）の製造］
　ヨウ素で染色した、ポリビニルアルコール樹脂製の長尺の延伸前フィルムを用意した。この延伸前フィルムを、当該延伸前フィルムの幅手方向に対して９０°の角度をなす長手方向に延伸して、長尺の偏光フィルムを得た。この偏光フィルムは、当該偏光フィルムの長手方向に吸収軸を有し、当該偏光フィルムの幅手方向に透過軸を有していた。 [Production example]
[Production Example 1: Production of polarizing film (linear polarizer)]
A long unstretched film made of polyvinyl alcohol resin dyed with iodine was prepared. This unstretched film was stretched in the longitudinal direction forming an angle of 90° with respect to the width direction of the unstretched film to obtain a long polarizing film. This polarizing film had an absorption axis in the longitudinal direction of the polarizing film and a transmission axis in the width direction of the polarizing film.
　［製造例２－１：λ／２板Ａの製造］
　環状オレフィン重合体を溶融押出法でフィルム状に成形して得られた長尺の環状オレフィン樹脂フィルム（日本ゼオン社製「ゼオノアフィルム」、ガラス転移温度１２６℃）を、第１樹脂フィルム（延伸前フィルム）として用意した。当該第１樹脂フィルムを形成する環状オレフィン樹脂は正の固有複屈折値を有する樹脂である。
　この環状オレフィン樹脂フィルムに対し、当該環状オレフィン樹脂フィルムの幅手方向への延伸処理を施して、長尺のλ／２板を得た。前記の幅手方向への延伸処理は、延伸温度１２０℃～１５０℃、延伸倍率２．０倍～５．０倍の範囲において、下記表１の実施例１の第１光学異方性層の欄に記載の物性値（Ｒｅ１、Ｒｔｈ１）のλ／２板が得られるように設定した。このようにして長尺のλ／２板Ａを得た。このλ／２板Ａの膜厚は５０μｍであった。このλ／２板Ａについて、面内位相差及び厚み方向の位相差の測定を上記方法によって行った。測定されたＲｅ１（５９０）は２８０ｎｍ、Ｒｔｈ１（５９０）は１６８ｎｍ、ｎｘ１は１．５３３９、ｎｙ１は１．５２８３、ｎｚ１は１．５２７８であった。この結果からｎｘ１、ｎｙ１、及びｎｚ１の関係は、ｎｘ１＞ｎｙ１＞ｎｚ１であり、式（１）を満たしていた。 [Production Example 2-1: Production of λ/2 Plate A]
A long cyclic olefin resin film (“ZEONOR film” manufactured by Nippon Zeon Co., Ltd., glass transition temperature 126° C.) obtained by molding a cyclic olefin polymer into a film by a melt extrusion method was used as a first resin film (before stretching). Prepared as a film). The cyclic olefin resin forming the first resin film is a resin having a positive intrinsic birefringence value.
The cyclic olefin resin film was stretched in the width direction of the cyclic olefin resin film to obtain a long λ/2 plate. The stretching treatment in the width direction was performed by stretching the first optically anisotropic layer of Example 1 in Table 1 below at a stretching temperature of 120° C. to 150° C. and a stretching ratio of 2.0 times to 5.0 times. It was set so that a λ/2 plate having the physical property values (Re1, Rth1) described in the column could be obtained. In this way, a long λ/2 plate A was obtained. The film thickness of this λ/2 plate A was 50 μm. The in-plane retardation and the thickness direction retardation of this λ/2 plate A were measured by the above-described methods. The measured Re1 (590) was 280 nm, Rth1 (590) was 168 nm, nx1 was 1.5339, ny1 was 1.5283, and nz1 was 1.5278. From this result, the relationship between nx1, ny1 and nz1 was nx1>ny1>nz1, which satisfied the formula (1).
　［製造例２－２：λ／２板Ｂの製造］
　環状オレフィン重合体を溶融押出法でフィルム状に成形して得られた長尺の環状オレフィン樹脂フィルム（日本ゼオン社製「ゼオノアフィルム」、ガラス転移温度１２６℃）を、延伸前フィルムとして用意した。当該延伸前フィルムを形成する環状オレフィン樹脂は正の固有複屈折値を有する樹脂である。
　この環状オレフィン樹脂フィルムに対し、当該環状オレフィン樹脂フィルムの幅手方向への延伸処理を施して、長尺のλ／２板を得た。前記の幅手方向への延伸処理は、延伸温度１２０℃～１５０℃、延伸倍率２．０倍～５．０倍の範囲において、下記表２の比較例２の第１光学異方性層の欄に記載の物性値（Ｒｅ１、Ｒｔｈ１）のλ／２板が得られるように設定した。このようにして長尺のλ／２板Ｂを得た。このλ／２板Ｂの膜厚は５０μｍであった。このλ／２板Ｂについて、面内位相差及び厚み方向の位相差の測定を上記方法によって行った。測定されたＲｅ１（５９０）は２８０ｎｍ、Ｒｔｈ１（５９０）は１９０ｎｍ、ｎｘ１は１．５３４１、ｎｙ１は１．５２８５、ｎｚ１は１．５２７５であった。この結果からｎｘ１、ｎｙ１、及びｎｚ１の関係は、ｎｘ１＞ｎｙ１＞ｎｚ１であり、式（１）を満たしていた。 [Production Example 2-2: Production of λ/2 Plate B]
A long cyclic olefin resin film (“Zeonoa film” manufactured by Nippon Zeon Co., Ltd., glass transition temperature 126° C.) obtained by molding a cyclic olefin polymer into a film by a melt extrusion method was prepared as a film before stretching. The cyclic olefin resin forming the unstretched film is a resin having a positive intrinsic birefringence value.
The cyclic olefin resin film was stretched in the width direction of the cyclic olefin resin film to obtain a long λ/2 plate. The stretching treatment in the width direction was performed by stretching the first optically anisotropic layer of Comparative Example 2 in Table 2 below at a stretching temperature of 120° C. to 150° C. and a stretching ratio of 2.0 times to 5.0 times. It was set so that a λ/2 plate having the physical property values (Re1, Rth1) described in the column could be obtained. In this way, a long λ/2 plate B was obtained. The film thickness of this λ/2 plate B was 50 μm. The in-plane retardation and the thickness direction retardation of the λ/2 plate B were measured by the above-described methods. The measured Re1 (590) was 280 nm, Rth1 (590) was 190 nm, nx1 was 1.5341, ny1 was 1.5285, and nz1 was 1.5275. From this result, the relationship between nx1, ny1 and nz1 was nx1>ny1>nz1, which satisfied the formula (1).
　［製造例３－１：λ／４板Ａ～Ｅ（実施例１～４および比較例３の第２光学異方性層）の製造］
　（３－１－１：第２樹脂フィルム（延伸前フィルム）の製造）
　負の固有複屈折値を有する樹脂として、スチレン－マレイン酸共重合体樹脂（ノヴァ・ケミカル社製「Ｄａｙｌａｒｋ　Ｄ３３２」、ガラス転移温度１３０℃、オリゴマー成分含有量３重量％）を用意した。
　保護層用のアクリル樹脂として、住友化学社製「スミペックスＨＴ－５５Ｘ」（ガラス転移温度１０５℃）を用意した。
　接着剤として、変性したエチレン－酢酸ビニル共重合体（三菱化学社製「モディックＡＰ　Ａ５４３」、ビカット軟化点８０℃）を用意した。 [Production Example 3-1: Production of λ/4 Plates A to E (Second Optically Anisotropic Layer of Examples 1 to 4 and Comparative Example 3)]
(3-1-1: Production of Second Resin Film (Film Before Stretching))
As a resin having a negative intrinsic birefringence value, a styrene-maleic acid copolymer resin (“Daylark D332” manufactured by Nova Chemical Co., glass transition temperature 130° C., oligomer component content 3% by weight) was prepared.
As an acrylic resin for the protective layer, “SUMIPEX HT-55X” (glass transition temperature 105° C.) manufactured by Sumitomo Chemical Co., Ltd. was prepared.
As an adhesive, a modified ethylene-vinyl acetate copolymer (“Modic AP A543” manufactured by Mitsubishi Chemical Co., Vicat softening point 80° C.) was prepared.
　用意したスチレン－マレイン酸共重合体樹脂、アクリル樹脂及び接着剤を共押出して、アクリル樹脂の層、接着剤の層、スチレン－マレイン酸共重合体樹脂の層、接着剤の層及びアクリル樹脂の層をこの順に備える長尺の第２樹脂フィルムを得た。 The prepared styrene-maleic acid copolymer resin, acrylic resin and adhesive are co-extruded to form an acrylic resin layer, an adhesive layer, a styrene-maleic acid copolymer resin layer, an adhesive layer and an acrylic resin layer. A long second resin film having layers in this order was obtained.
　（３－１－２：λ／４板の製造）
　（３－１－１）で製造した第２樹脂フィルムに対し、当該第２樹脂フィルムの幅手方向及び長手方向への延伸処理（二方向延伸処理）を施して、長尺のλ／４板を得た。前記の二方向延伸処理の条件は、下記表１の実施例１～４及び比較例３の第２光学異方性層の欄に記載の物性値（Ｒｅ２、Ｒｔｈ２）のλ／４板が得られるように設定した。具体的には、各例で用いるλ／４板が得られるようにフィルム幅手方向への延伸処理の条件を、延伸温度１１０℃～１４０℃、延伸倍率１．５～４．０の範囲で設定し、フィルム長手方向への延伸処理の条件を、延伸温度１１０℃～１４０℃、延伸倍率１．５～４．０の範囲で設定した。このようにしてλ／４板Ａ～Ｆを得た。得られたλ／４板Ａ～Ｆの膜厚は、それぞれ、４０μｍであった。
　得られたλ／４板Ａ～Ｅについて、それぞれ、面内位相差及び厚み方向の位相差の測定を上記方法によって行った。各λ／４板の、アクリル樹脂の層及び接着剤の層には、位相差が発現しなかった。
　λ／４板Ａの測定結果は、Ｒｅ２（５９０）は１４７ｎｍ、Ｒｔｈ２（５９０）は－１３２ｎｍ、ｎｘ２は１．５５８２、ｎｙ２は１．５５４５、ｎｚ２は１．５５９７であった。
　λ／４板Ｂの測定結果は、Ｒｅ２（５９０）は１４７ｎｍ、Ｒｔｈ２（５９０）は－１６２ｎｍ、ｎｘ２は１．５５８０、ｎｙ２は１．５５４３、ｎｚ２は１．５６０２であった。
　λ／４板Ｃの測定結果は、Ｒｅ２（５９０）は１４７ｎｍ、Ｒｔｈ２（５９０）は－１９１ｎｍ、ｎｘ２は１．５５７７、ｎｙ２は１．５５４０、ｎｚ２は１．５６０７であった。
　λ／４板Ｄの測定結果は、Ｒｅ２（５９０）は１４７ｎｍ、Ｒｔｈ２（５９０）は－２２０ｎｍ、ｎｘ２は１．５５７５、ｎｙ２は１．５５３８、ｎｚ２は１．５６１１であった。
　λ／４板Ｅの測定結果は、Ｒｅ２（５９０）は１４７ｎｍ、Ｒｔｈ２（５９０）は－１６２ｎｍ、ｎｘ２は１．５５８０、ｎｙ２は１．５５４３、ｎｚ２は１．５６０２であった。
　これらの結果から、λ／４板Ａ～Ｅのいずれも、ｎｘ２、ｎｙ２、及びｎｚ２の関係は、ｎｚ２＞ｎｘ２＞ｎｙ２であり、式（２）を満たしていた。 (3-1-2: Production of λ/4 plate)
A long λ/4 plate is obtained by subjecting the second resin film produced in (3-1-1) to a stretching treatment (bidirectional stretching treatment) in the width direction and the longitudinal direction of the second resin film. Got The conditions for the above-mentioned bidirectional stretching treatment are λ/4 plates having physical properties (Re2, Rth2) described in the columns of the second optically anisotropic layer in Examples 1 to 4 and Comparative Example 3 in Table 1 below. I was set to be able to. Specifically, in order to obtain the λ/4 plate used in each example, the stretching conditions in the width direction of the film are set such that the stretching temperature is 110° C. to 140° C. and the stretching ratio is 1.5 to 4.0. The conditions for the stretching treatment in the longitudinal direction of the film were set at a stretching temperature of 110° C. to 140° C. and a stretching ratio of 1.5 to 4.0. Thus, λ/4 plates A to F were obtained. The thickness of each of the obtained λ/4 plates A to F was 40 μm.
The in-plane retardation and the retardation in the thickness direction of each of the obtained λ/4 plates A to E were measured by the above method. No retardation was developed in the acrylic resin layer and the adhesive layer of each λ/4 plate.
The measurement results of the λ/4 plate A were Re2(590) of 147 nm, Rth2(590) of -132 nm, nx2 of 1.5582, ny2 of 1.5545, and nz2 of 1.5597.
The measurement results of the λ/4 plate B were Re2(590) of 147 nm, Rth2(590) of -162 nm, nx2 of 1.5580, ny2 of 1.5543, and nz2 of 1.5602.
The measurement results of the λ/4 plate C were Re2(590) of 147 nm, Rth2(590) of -191 nm, nx2 of 1.5577, ny2 of 1.5540, and nz2 of 1.5607.
The measurement results of the λ/4 plate D were Re2(590) of 147 nm, Rth2(590) of −220 nm, nx2 of 1.5575, ny2 of 1.5538, and nz2 of 1.5611.
The measurement results of the λ/4 plate E were Re2(590) of 147 nm, Rth2(590) of -162 nm, nx2 of 1.5580, ny2 of 1.5543, and nz2 of 1.5602.
From these results, in all of the λ/4 plates A to E, the relationship of nx2, ny2, and nz2 was nz2>nx2>ny2, which satisfied the expression (2).
　［製造例３－２：λ／４板Ｆの製造］
　製造例３－１の（３－１－１）で製造した延伸前フィルムを用いて、以下の方法によりλ／４板Ｆを製造した。
　延伸前フィルムに対し、当該延伸前フィルムの幅手方向への延伸処理を施して、長尺のλ／４板Ｆを得た。前記の幅手方向への延伸処理は、延伸温度１１０℃～１４０℃、延伸倍率１．５倍～４．０倍の範囲において、下記表２の比較例１の第２光学異方性層の欄に記載の物性値（Ｒｅ２、Ｒｔｈ２）のλ／４板が得られるように設定した。このようにして長尺のλ／４板Ｆを得た。λ／４板Ｆの膜厚は４０μｍであった。
　λ／４板Ｆについて、面内位相差及び厚み方向の位相差の測定を上記方法によって行った。得られたλ／４板のアクリル樹脂の層及び接着剤の層には、位相差が発現しなかった。測定されたＲｅ２（５９０）は１４７ｎｍ、Ｒｔｈ２（５９０）は－８８ｎｍ、ｎｘ２は１．５５８６、ｎｙ２は１．５５４９、ｎｚ２は１．５５８９であった。この結果から、ｎｘ２、ｎｙ２、及びｎｚ２の関係は、ｎｚ２＞ｎｘ２＞ｎｙ２であった。 [Production Example 3-2: Production of λ/4 Plate F]
Using the unstretched film produced in (3-1-1) of Production Example 3-1, a λ/4 plate F was produced by the following method.
The pre-stretched film was stretched in the width direction of the pre-stretched film to obtain a long λ/4 plate F. The stretching treatment in the width direction was carried out at a stretching temperature of 110° C. to 140° C. and a stretching ratio of 1.5 times to 4.0 times. It was set so that a λ/4 plate having the physical property values (Re2, Rth2) described in the column could be obtained. Thus, a long λ/4 plate F was obtained. The film thickness of the λ/4 plate F was 40 μm.
The in-plane retardation and the retardation in the thickness direction of the λ/4 plate F were measured by the above method. No retardation was developed in the obtained λ/4 plate acrylic resin layer and adhesive layer. The measured Re2 (590) was 147 nm, Rth2 (590) was -88 nm, nx2 was 1.5586, ny2 was 1.5549, and nz2 was 1.5589. From this result, the relationship between nx2, ny2, and nz2 was nz2>nx2>ny2.
　［実施例１］
　長尺の偏光フィルム、長尺のλ／２板Ａ及び長尺のλ／４板Ａをそれぞれ切り出して、枚葉の偏光フィルム、枚葉のλ／２板Ａ及び枚葉のλ／４板Ａを得た。これらの枚葉の偏光フィルム、枚葉のλ／２板Ａ及び枚葉のλ／４板Ａを、粘着剤（日東電工社製「ＣＳ９６２１」）を用いて貼り合わせて、偏光フィルム、粘着層、λ／２板Ａ（第１光学異方性層）、粘着層及びλ／４板Ａ（第２光学異方性層）をこの順に備える円偏光板を得た。この円偏光板は実施形態１に対応する態様である（図１を参照）。この円偏光板において、λ／２板Ａが第１光学異方性層であり、λ／４板Ａが第２光学異方性層である。前記の貼り合わせは、偏光フィルム側から見て、偏光フィルムの透過軸に対してλ／２板Ａの遅相軸が時計回りになす角度θＡ１が４５°、及び、偏光フィルムの透過軸に対してλ／４板Ａの遅相軸が時計回りになす角度θＢ１が１３５°となるように行った。得られた円偏光板を、前記の方法で評価した。
　本例の円偏光板に含まれる光学異方性積層体の、Ｒｅ（４５０）、Ｒｅ（５５０）及びＲｅ（６５０）は、下記式（３）を満たすものであった。
　Ｒｅ（４５０）＜Ｒｅ（５５０）＜Ｒｅ（６５０）　　式（３）
　また、光学異方性積層体において、第１光学異方性層は下記式（１）を満たし、第２光学異方性層は下記式（２）を満たし、ＮＺ１とＮＺ２との和は０．７であった。
　ｎｘ１＞ｎｙ１≧ｎｚ１　　　　　　　　　　　　　式（１）
　ｎｚ２＞ｎｘ２＞ｎｙ２　　　　　　　　　　　　　式（２） [Example 1]
A long polarizing film, a long .lamda./2 plate A and a long .lamda./4 plate A are respectively cut out to obtain a sheet of polarizing film, a sheet of .lamda./2 plate A and a sheet of .lamda./4 plate. I got A. The sheet-shaped polarizing film, the sheet-shaped λ/2 plate A and the sheet-shaped λ/4 plate A are attached to each other using an adhesive (“CS9621” manufactured by Nitto Denko Corporation) to obtain a polarizing film and an adhesive layer. , A λ/2 plate A (first optically anisotropic layer), an adhesive layer and a λ/4 plate A (second optically anisotropic layer) were obtained in this order to obtain a circularly polarizing plate. This circularly polarizing plate is a mode corresponding to the first embodiment (see FIG. 1). In this circularly polarizing plate, the λ/2 plate A is the first optically anisotropic layer and the λ/4 plate A is the second optically anisotropic layer. The above-mentioned bonding is such that when viewed from the polarizing film side, the angle θA1 formed by the slow axis of the λ/2 plate A clockwise with respect to the transmission axis of the polarizing film is 45°, and the transmission axis of the polarizing film is Then, the angle θB1 formed by the slow axis of the λ/4 plate A in the clockwise direction was set to 135°. The obtained circularly polarizing plate was evaluated by the method described above.
Re(450), Re(550) and Re(650) of the optically anisotropic layered product included in the circularly polarizing plate of this example satisfied the following formula (3).
Re(450)<Re(550)<Re(650) Formula (3)
In the optically anisotropic laminate, the first optically anisotropic layer satisfies the following formula (1), the second optically anisotropic layer satisfies the following formula (2), and the sum of NZ1 and NZ2 is 0. It was .7.
nx1>ny1≧nz1 Formula (1)
nz2>nx2>ny2 Formula (2)
　［実施例２］
　長尺のλ／４板Ａを長尺のλ／４板Ｂに変更したこと以外は実施例１と同じ操作を行って、偏光フィルム、粘着層、λ／２板Ａ、粘着層及びλ／４板Ｂをこの順に備える円偏光板を得た。この円偏光板において、λ／２板Ａが第１光学異方性層であり、λ／４板Ｂが第２光学異方性層である。得られた円偏光板を前記の方法により評価した。この円偏光板に含まれる光学異方性積層体の、Ｒｅ（４５０）、Ｒｅ（５５０）及びＲｅ（６５０）は、上記式（３）を満たすものであった。また、光学異方性積層体において、第１光学異方性層は上記式（１）を満たし、第２光学異方性層は上記式（２）を満たし、ＮＺ１とＮＺ２との和は０．５であった。 [Example 2]
The same operation as in Example 1 was performed except that the long λ/4 plate A was changed to the long λ/4 plate B, and the polarizing film, the adhesive layer, the λ/2 plate A, the adhesive layer and λ/ A circularly polarizing plate having 4 plates B in this order was obtained. In this circularly polarizing plate, the λ/2 plate A is the first optically anisotropic layer and the λ/4 plate B is the second optically anisotropic layer. The obtained circularly polarizing plate was evaluated by the above method. Re(450), Re(550) and Re(650) of the optically anisotropic laminate contained in this circularly polarizing plate satisfied the above formula (3). In the optically anisotropic laminate, the first optically anisotropic layer satisfies the above formula (1), the second optically anisotropic layer satisfies the above formula (2), and the sum of NZ1 and NZ2 is 0. It was 0.5.
　［実施例３］
　長尺のλ／４板Ａを長尺のλ／４板Ｃに変更したこと以外は実施例１と同じ操作を行って、偏光フィルム、粘着層、λ／２板Ａ、粘着層及びλ／４板Ｃをこの順に備える円偏光板を得た。この円偏光板において、λ／２板Ａが第１光学異方性層であり、λ／４板Ｃが第２光学異方性層である。得られた円偏光板を前記の方法により評価した。この円偏光板に含まれる光学異方性積層体の、Ｒｅ（４５０）、Ｒｅ（５５０）及びＲｅ（６５０）は、上記式（３）を満たすものであった。また、光学異方性積層体において、第１光学異方性層は上記式（１）を満たし、第２光学異方性層は上記式（２）を満たし、ＮＺ１とＮＺ２との和は０．３であった。 [Example 3]
The same operation as in Example 1 was performed except that the long λ/4 plate A was changed to the long λ/4 plate C, and the polarizing film, the adhesive layer, the λ/2 plate A, the adhesive layer and λ/ A circularly polarizing plate having 4 plates C in this order was obtained. In this circularly polarizing plate, the λ/2 plate A is the first optically anisotropic layer and the λ/4 plate C is the second optically anisotropic layer. The obtained circularly polarizing plate was evaluated by the above method. Re(450), Re(550) and Re(650) of the optically anisotropic laminate contained in this circularly polarizing plate satisfied the above formula (3). In the optically anisotropic laminate, the first optically anisotropic layer satisfies the above formula (1), the second optically anisotropic layer satisfies the above formula (2), and the sum of NZ1 and NZ2 is 0. It was .3.
　［実施例４］
　長尺のλ／４板Ａを長尺のλ／４板Ｄに変更したこと以外は実施例１と同じ操作を行って、偏光フィルム、粘着層、λ／２板Ａ、粘着層及びλ／４板Ｄをこの順に備える円偏光板を得た。この円偏光板において、λ／２板Ａが第１光学異方性層であり、λ／４板Ｄが第２光学異方性層である。得られた円偏光板を前記の方法により評価した。この円偏光板に含まれる光学異方性積層体の、Ｒｅ（４５０）、Ｒｅ（５５０）及びＲｅ（６５０）は、上記式（３）を満たすものであった。また、光学異方性積層体において、第１光学異方性層は上記式（１）を満たし、第２光学異方性層は上記式（２）を満たし、ＮＺ１とＮＺ２との和は０．１であった。 [Example 4]
The same operation as in Example 1 was performed except that the long λ/4 plate A was changed to the long λ/4 plate D, and the polarizing film, the adhesive layer, the λ/2 plate A, the adhesive layer and λ/ A circularly polarizing plate having 4 plates D in this order was obtained. In this circularly polarizing plate, the λ/2 plate A is the first optically anisotropic layer and the λ/4 plate D is the second optically anisotropic layer. The obtained circularly polarizing plate was evaluated by the above method. Re(450), Re(550) and Re(650) of the optically anisotropic laminate contained in this circularly polarizing plate satisfied the above formula (3). In the optically anisotropic laminate, the first optically anisotropic layer satisfies the above formula (1), the second optically anisotropic layer satisfies the above formula (2), and the sum of NZ1 and NZ2 is 0. It was 1.
　［比較例１］
　長尺のλ／４板Ａを長尺のλ／４板Ｆに変更したこと以外は実施例１と同じ操作を行って、偏光フィルム、粘着層、λ／２板Ａ、粘着層及びλ／４板Ｆをこの順に備える円偏光板を得た。この円偏光板において、λ／２板Ａが第１光学異方性層であり、λ／４板Ｆが第２光学異方性層である。得られた円偏光板を前記の方法により評価した。この円偏光板に含まれる光学異方性積層体の、Ｒｅ（４５０）、Ｒｅ（５５０）及びＲｅ（６５０）は、Ｒｅ（４５０）＜Ｒｅ（５５０）＜Ｒｅ（６５０）であり上記式（３）を満たすものであった。光学異方性積層体において、第１光学異方性層は上記式（１）を満たし、第２光学異方性層は上記式（２）を満たし、ＮＺ１とＮＺ２との和は１．０であった。 [Comparative Example 1]
The same operation as in Example 1 was performed except that the long λ/4 plate A was changed to the long λ/4 plate F, and the polarizing film, the adhesive layer, the λ/2 plate A, the adhesive layer and λ/ A circularly polarizing plate having 4 plates F in this order was obtained. In this circularly polarizing plate, the λ/2 plate A is the first optically anisotropic layer and the λ/4 plate F is the second optically anisotropic layer. The obtained circularly polarizing plate was evaluated by the above method. The Re(450), Re(550) and Re(650) of the optically anisotropic laminate contained in this circularly polarizing plate are Re(450)<Re(550)<Re(650) and are represented by the above formula ( 3) was satisfied. In the optically anisotropic laminate, the first optically anisotropic layer satisfies the above formula (1), the second optically anisotropic layer satisfies the above formula (2), and the sum of NZ1 and NZ2 is 1.0. Met.
　［比較例２］
　以下の点を変更したこと以外は、実施例１と同じ操作を行って、偏光フィルム、粘着層、λ／２板Ｂ、粘着層及びλ／４板Ｆをこの順に備える円偏光板を得た。この円偏光板において、λ／２板Ｂが第１光学異方性層であり、λ／４板Ｆが第２光学異方性層である。得られた円偏光板を前記の方法により評価した。また、この円偏光板に含まれる光学異方性積層体の、Ｒｅ（４５０）、Ｒｅ（５５０）及びＲｅ（６５０）は、Ｒｅ（４５０）＜Ｒｅ（５５０）＜Ｒｅ（６５０）であり上記式（３）を満たすものであった。光学異方性積層体において、第１光学異方性層は上記式（１）を満たし、第２光学異方性層は上記式（２）を満たし、ＮＺ１とＮＺ２との和は１．０８であった。
　（変更点）
・長尺のλ／２板Ａを長尺のλ／２板Ｂに変更した。
・長尺のλ／４板Ａを長尺のλ／４板Ｆに変更した。
・層の貼り合わせは、偏光フィルム側から見て、偏光フィルムの透過軸に対してλ／２板Ｂの遅相軸が時計回りになす角度θＡ１が２２．５°、及び、偏光フィルムの透過軸に対してλ／４板Ｆの遅相軸が時計回りになす角度θＢ１が９０°となるように行った。 [Comparative example 2]
The same operation as in Example 1 was performed except that the following points were changed to obtain a circularly polarizing plate having a polarizing film, an adhesive layer, a λ/2 plate B, an adhesive layer and a λ/4 plate F in this order. .. In this circularly polarizing plate, the λ/2 plate B is the first optically anisotropic layer and the λ/4 plate F is the second optically anisotropic layer. The obtained circularly polarizing plate was evaluated by the above method. Further, Re(450), Re(550) and Re(650) of the optically anisotropic laminate contained in this circularly polarizing plate are Re(450)<Re(550)<Re(650), It satisfied the formula (3). In the optically anisotropic laminate, the first optically anisotropic layer satisfies the above formula (1), the second optically anisotropic layer satisfies the above formula (2), and the sum of NZ1 and NZ2 is 1.08. Met.
(change point)
The long λ/2 plate A was changed to the long λ/2 plate B.
The long λ/4 plate A was changed to the long λ/4 plate F.
The layers are stuck together such that when viewed from the polarizing film side, the angle θA1 formed by the slow axis of the λ/2 plate B in the clockwise direction with respect to the transmission axis of the polarizing film is 22.5°, and the transmission of the polarizing film. The angle θB1 formed by the slow axis of the λ/4 plate F clockwise with respect to the axis was set to 90°.
　［比較例３］
　以下の点を変更したこと以外は、実施例１と同じ操作を行って、偏光フィルム、粘着層、λ／２板Ｂ、粘着層及びλ／４板Ｅをこの順に備える円偏光板を得た。この円偏光板において、λ／２板Ｂが第１光学異方性層であり、λ／４板Ｅが第２光学異方性層である。得られた円偏光板を前記の方法により評価した。また、この円偏光板に含まれる光学異方性積層体の、Ｒｅ（４５０）、Ｒｅ（５５０）及びＲｅ（６５０）は、Ｒｅ（４５０）＜Ｒｅ（５５０）＜Ｒｅ（６５０）であり上記式（３）を満たすものであった。また、光学異方性積層体において、第１光学異方性層は上記式（１）を満たし、第２光学異方性層は上記式（２）を満たし、ＮＺ１とＮＺ２との和は０．５８であった。
　（変更点）
・長尺のλ／２板Ａを長尺のλ／２板Ｂに変更した。
・長尺のλ／４板Ａを長尺のλ／４板Ｅに変更した。
・層の貼り合わせは、偏光フィルム側から見て、偏光フィルムの透過軸に対してλ／２板Ｂの遅相軸が時計回りになす角度θＡ１が２２．５°、及び、偏光フィルムの透過軸に対してλ／４板Ｆの遅相軸が時計回りになす角度θＢ１が９０°となるように行った。 [Comparative Example 3]
The same operation as in Example 1 was performed except that the following points were changed to obtain a circularly polarizing plate including a polarizing film, an adhesive layer, a λ/2 plate B, an adhesive layer and a λ/4 plate E in this order. .. In this circularly polarizing plate, the λ/2 plate B is the first optically anisotropic layer and the λ/4 plate E is the second optically anisotropic layer. The obtained circularly polarizing plate was evaluated by the above method. Further, Re(450), Re(550) and Re(650) of the optically anisotropic laminate contained in this circularly polarizing plate are Re(450)<Re(550)<Re(650), It satisfied the formula (3). In the optically anisotropic laminate, the first optically anisotropic layer satisfies the above formula (1), the second optically anisotropic layer satisfies the above formula (2), and the sum of NZ1 and NZ2 is 0. It was 0.58.
(change point)
The long λ/2 plate A was changed to the long λ/2 plate B.
The long λ/4 plate A was changed to the long λ/4 plate E.
The layers are stuck together such that when viewed from the polarizing film side, the angle θA1 formed by the slow axis of the λ/2 plate B in the clockwise direction with respect to the transmission axis of the polarizing film is 22.5°, and the transmission of the polarizing film. The angle θB1 formed by the slow axis of the λ/4 plate F clockwise with respect to the axis was set to 90°.
　［比較例４］
　下記の方法（特開２０１０-２６６７２３号公報の実施例１と同じ方法）で比較例４の円偏光板を製造した。
　（Ｃ４－１）フィルムＣ１(固有複屈折値が正の樹脂を含むフィルム)の製造
　ノルボルネン系重合体（日本ゼオン社製、「ＺＥＯＮＯＲ１４２０」、ガラス転移温度：１３６℃）からなる第１未延伸フィルムのロール巻状体を溶融押出し成形により得た。次いで、この第１未延伸フィルムのロール巻状体を、テンター延伸機(特開２０１０－２６６７２３号公報の図２参照)を用いて、延伸温度１４７℃、延伸倍率１．７倍、延伸速度１３ｍｍ／分で、幅手方向に対して４５°の方向へ斜め延伸を行うことにより、フィルムＣ１のロール巻状体を得た。得られたフィルムＣ１は、Ｎｚ係数（ＮＺ１）が１．１、Ｒｅ１（５９０）が６６ｎｍ、幅手方向に対して遅相軸がなす角度は４４．８°であり、その厚みが１２０μｍであった。 [Comparative Example 4]
The circularly polarizing plate of Comparative Example 4 was manufactured by the following method (the same method as Example 1 in JP 2010-266723 A).
(C4-1) Production of Film C1 (a film containing a resin having a positive intrinsic birefringence value) A first unstretched film made of a norbornene-based polymer (“ZEONOR1420” manufactured by Nippon Zeon Co., Ltd., glass transition temperature: 136° C.) The roll-wound body was obtained by melt extrusion molding. Then, the roll-shaped body of the first unstretched film was stretched using a tenter stretching machine (see FIG. 2 of JP 2010-266723 A) at a stretching temperature of 147° C., a stretching ratio of 1.7 times, and a stretching speed of 13 mm. The film was roll-formed into a roll C1 by obliquely stretching the film C1 in a direction of 45° with respect to the width direction. The film C1 thus obtained had an Nz coefficient (NZ1) of 1.1, a Re1 (590) of 66 nm, an angle formed by the slow axis with respect to the width direction of 44.8°, and a thickness of 120 μm. It was
　（Ｃ４－２）フィルムＣ２（固有複屈折値が負の樹脂を含むフィルム）の製造
　数平均粒径０．４μｍの弾性体粒子を含むポリメチルメタクリレート樹脂からなるａ層と、スチレン－マレイン酸共重合体（ノヴァ・ケミカル社製、商品名「Ｄａｙｌａｒｋ　Ｄ３３２」、ガラス転移温度：１３０℃、オリゴマー成分含有量：３重量％）からなるｂ層とを、ａ層（３０μｍ）－ｂ層（３０μｍ）－ａ層（３０μｍ）の順で備える未延伸積層体のロール巻状体（第２未延伸フィルムのロール巻状体）を共押出し成形により得た。次いで、このロール巻状体から未延伸積層体を引き出し、（Ｃ４－１）と同じテンター延伸機を用いて、延伸温度１３８℃、延伸倍率１．７倍、延伸速度８ｍｍ／ｍｉｎで幅手方向に対して４５°方向への斜め延伸を行うことにより、フィルムＣ２のロール巻状体を得た。得られたフィルムＣ２は、Ｎｚ係数（ＮＺ２）が－０．１、Ｒｅ２（５９０）が６６ｎｍ、幅手方向に対して遅相軸がなす角度は－４５．２°であり、その厚みが１３０μｍであった。 (C4-2) Production of Film C2 (Film Containing Resin Having Negative Birefringence Value) A layer made of polymethylmethacrylate resin containing elastic particles having a number average particle diameter of 0.4 μm and styrene-maleic acid copolymer A layer (30 μm)-b layer (30 μm) consisting of a polymer (Nova Chemical Co., trade name “Daylark D332”, glass transition temperature: 130° C., oligomer component content: 3% by weight) A roll wound body (roll wound body of the second unstretched film) of the unstretched laminate provided in the order of -a layer (30 μm) was obtained by coextrusion molding. Then, the unstretched laminate was pulled out from this roll-shaped body and stretched at a stretching temperature of 138° C., a stretching ratio of 1.7 times, and a stretching speed of 8 mm/min using the same tenter stretching machine as in (C4-1). By performing oblique stretching in the direction of 45° with respect to, a roll wound body of the film C2 was obtained. The obtained film C2 has an Nz coefficient (NZ2) of −0.1, a Re2 (590) of 66 nm, an angle formed by the slow axis with respect to the width direction of −45.2°, and a thickness of 130 μm. Met.
　（Ｃ４－３）光学異方性積層体の製造
　（Ｃ４－１）で得られたフィルムＣ１と、（Ｃ４－２）で得られたフィルムＣ２とを、それぞれ引き出して、面内遅相軸が互いに平行となるように、積層装置（特開２０１０－２６６７２３号公報の図３参照)を用いてロールトゥーロール法により積層して、光学異方性積層体Ｃ３のロール巻状体を得た。 (C4-3) Production of Optically Anisotropic Laminated Body The film C1 obtained in (C4-1) and the film C2 obtained in (C4-2) are drawn out to obtain an in-plane slow axis By using a laminating apparatus (see FIG. 3 of JP 2010-266723A) so as to be parallel to each other, the layers were laminated by a roll-to-roll method to obtain a roll winding body of an optically anisotropic laminate C3.
　（Ｃ４－４）円偏光板の製造
　（Ｃ４－３）で得られた光学異方性積層体Ｃ３と、偏光フィルム（サンリッツ社製、ＨＬＣ２-５６１８Ｓ、厚さ１８０μｍ）とを、積層装置（特開２０１０－２６６７２３号公報の図４参照)を用いてロールトゥロール法により積層して、円偏光フィルムを製造し、これを所定の大きさに裁断して、円偏光板を得た。 (C4-4) Production of Circularly Polarizing Plate The optically anisotropic laminate C3 obtained in (C4-3) and a polarizing film (manufactured by Sanritz Co., HLC2-5618S, thickness 180 μm) were combined with each other by a laminating device (special (See FIG. 4 of Kai 2010-266723) was laminated by a roll-to-roll method to produce a circularly polarizing film, which was cut into a predetermined size to obtain a circularly polarizing plate.
　得られた円偏光板を、実施例１と同様に、前記の評価方法で評価した。本例の円偏光板に含まれる光学異方性積層体の、Ｒｅ（４５０）、Ｒｅ（５５０）及びＲｅ（６５０）の関係は、Ｒｅ（４５０）＞Ｒｅ（５５０）＞Ｒｅ（６５０）であり、式（３）を満たさなかった。また、光学異方性積層体において、第１光学異方性層は下記式（１）を満たし、第２光学異方性層は下記式（２）を満たし、ＮＺ１とＮＺ２との和は１．０であった。 The obtained circularly polarizing plate was evaluated by the above-described evaluation method in the same manner as in Example 1. The relationship of Re(450), Re(550) and Re(650) of the optically anisotropic laminate contained in the circularly polarizing plate of this example is Re(450)>Re(550)>Re(650). Yes, the formula (3) was not satisfied. In the optically anisotropic laminate, the first optically anisotropic layer satisfies the following formula (1), the second optically anisotropic layer satisfies the following formula (2), and the sum of NZ1 and NZ2 is 1. It was 0.0.
　［結果］
　実施例及び比較例の結果を、下記の表１及び表２に示す。表１及び表２において、略称の意味は、下記の通りである。
　ＣＯＰ：環状オレフィン樹脂
　ＰＳｔ：スチレン－マレイン酸共重合体樹脂
　Ｒｅ１（５９０）：測定波長５９０ｎｍにおけるλ／２板（第１光学異方性層）の面内位相差。
　Ｒｅ１（５５０）：測定波長５５０ｎｍにおけるλ／２板（第１光学異方性層）の面内位相差。
　Ｒｅ１（４５０）：測定波長４５０ｎｍにおけるλ／２板（第１光学異方性層）の面内位相差。
　Ｒｔｈ１（５９０）：測定波長５９０ｎｍにおけるλ／２板（第１光学異方性層）の厚み方向の位相差。
　θＡ１：偏光フィルム側から見て、偏光フィルムの透過軸に対してλ／２板（第１光学異方性層）の遅相軸が時計回りになす角度。
　ＮＺ１：λ／２板（第１光学異方性層）のＮＺ係数。
　Ｒｅ２（５９０）：測定波長５９０ｎｍにおけるλ／４板（第２光学異方性層）の面内位相差。
　Ｒｅ２（５５０）：測定波長５５０ｎｍにおけるλ／４板（第２光学異方性層）の面内位相差。
　Ｒｅ２（４５０）：測定波長４５９０ｎｍにおけるλ／４板（第２光学異方性層）の面内位相差。
　Ｒｔｈ２（５９０）：測定波長５９０ｎｍにおけるλ／４板（第２光学異方性層）の厚み方向の位相差。
　θＢ１：偏光フィルム側から見て、偏光フィルムの透過軸に対してλ／４板（第２光学異方性層）の遅相軸が時計回りになす角度。
　ＮＺ２：λ／４板（第２光学異方性層）のＮＺ係数。
　遅相軸のなす角：第１光学異方性層の遅相軸と、第２光学異方性層の遅相軸とのなす角。
　ΔＥ＊ａｂ（正面方向）：極角ρ＝０°から観察したときの色差。
　目視(正面方向)：極角ρ＝０°から目視観察したときの色差。
　ΔＥ＊ａｂ（斜め方向）：極角ρ＝６０°から観察したときの色差の平均。
　目視(斜め方向)：極角ρ＝６０°から目視観察したときの色差。
　＊１：本例のように、第１光学異方性層の遅相軸と第２光学異方性層の遅相軸とが直交しない場合、測定装置によってＲｅ１とＲｅ２との差が相違することがあるが、他の例と同様に、位相差計（Ａｘｏｍｅｔｒｉｃｓ社製「ＡｘｏＳｃａｎ」）で測定したＲｅ１（５５０）とＲｅ２（５５０）との差を記載した。 [result]
The results of Examples and Comparative Examples are shown in Tables 1 and 2 below. In Table 1 and Table 2, the meanings of the abbreviations are as follows.
COP: Cyclic olefin resin PSt: Styrene-maleic acid copolymer resin Re1 (590): In-plane retardation of λ/2 plate (first optically anisotropic layer) at a measurement wavelength of 590 nm.
Re1 (550): In-plane retardation of a λ/2 plate (first optically anisotropic layer) at a measurement wavelength of 550 nm.
Re1 (450): In-plane retardation of a λ/2 plate (first optically anisotropic layer) at a measurement wavelength of 450 nm.
Rth1 (590): Phase difference in the thickness direction of the λ/2 plate (first optically anisotropic layer) at a measurement wavelength of 590 nm.
θA1: An angle formed by the slow axis of the λ/2 plate (first optically anisotropic layer) in the clockwise direction with respect to the transmission axis of the polarizing film when viewed from the polarizing film side.
NZ1: NZ coefficient of λ/2 plate (first optical anisotropic layer).
Re2 (590): In-plane retardation of a λ/4 plate (second optically anisotropic layer) at a measurement wavelength of 590 nm.
Re2 (550): In-plane retardation of a λ/4 plate (second optically anisotropic layer) at a measurement wavelength of 550 nm.
Re2 (450): In-plane retardation of a λ/4 plate (second optically anisotropic layer) at a measurement wavelength of 4590 nm.
Rth2 (590): Phase difference in the thickness direction of the λ/4 plate (second optically anisotropic layer) at a measurement wavelength of 590 nm.
θB1: An angle formed by the slow axis of the λ/4 plate (second optically anisotropic layer) in the clockwise direction with respect to the transmission axis of the polarizing film as viewed from the polarizing film side.
NZ2: NZ coefficient of λ/4 plate (second optically anisotropic layer).
Angle formed by the slow axis: An angle formed by the slow axis of the first optically anisotropic layer and the slow axis of the second optically anisotropic layer.
ΔE * ab (front direction): Color difference observed from polar angle ρ=0°.
Visual (front direction): Color difference when visually observed from polar angle ρ=0°.
ΔE * ab (oblique direction): average of color difference observed from polar angle ρ=60°.
Visual observation (oblique direction): Color difference when visually observed from a polar angle ρ=60°.
*1: As in this example, when the slow axis of the first optically anisotropic layer and the slow axis of the second optically anisotropic layer are not orthogonal to each other, the difference between Re1 and Re2 differs depending on the measuring device. However, as in the other examples, the difference between Re1 (550) and Re2 (550) measured by a phase difference meter (“AxoScan” manufactured by Axometrics) was described.
Figure JPOXMLDOC01-appb-T000004
Figure JPOXMLDOC01-appb-T000004
Figure JPOXMLDOC01-appb-T000005
Figure JPOXMLDOC01-appb-T000005
　以上の結果によれば、実施例１～４の光学異方性積層体を備えた画像表示装置は、比較例１～４の光学異方性積層体を備えた画像表示装置と比較して、正面方向から観察した場合の表示面の色付きが同等に抑制されており、かつ傾斜方向から観察した場合の表示面の色付きが抑制されていることが分かる。上記結果から、本発明の光学異方性積層体を備える実施例１～４によれば、正面方向及び傾斜方向から観察した場合の表示面の色付きが抑制された画像表示装置を実現しうる。 According to the above results, the image display devices including the optically anisotropic laminates of Examples 1 to 4 were compared with the image display devices including the optically anisotropic laminates of Comparative Examples 1 to 4, It can be seen that the coloring of the display surface when viewed from the front direction is suppressed equally, and the coloring of the display surface when viewed from the tilt direction is suppressed. From the above results, according to Examples 1 to 4 including the optically anisotropic laminate of the present invention, it is possible to realize the image display device in which the coloring of the display surface when viewed from the front direction and the tilt direction is suppressed.
　［他の実施形態］
　（１）上記実施例１～４においては、λ／２板を第１光学異方性層に用い、λ／４板を第２光学異方性層に用いた光学異方性積層体を示したが、本発明はこれに限定されない。λ／２板を第２光学異方性層に用い、λ／４板を第１光学異方性層に用いた光学異方性積層体であってもよい。
　（２）上記実施例１～４においては、直線偏光子（偏光フィルム）の透過軸に対してλ／２板（第１光学異方性層）の遅相軸が時計回りになす角度θＡ１が４５°の光学異方性積層体を示したが、本発明はこれに限定されない。直線偏光子の吸収軸と、第１光学異方性層の遅相軸とのなす角が４５°の光学異方性積層体であってもよい。 [Other Embodiments]
(1) In Examples 1 to 4 described above, an optically anisotropic laminate using a λ/2 plate as the first optically anisotropic layer and a λ/4 plate as the second optically anisotropic layer was shown. However, the present invention is not limited to this. It may be an optically anisotropic laminate in which a λ/2 plate is used as the second optically anisotropic layer and a λ/4 plate is used as the first optically anisotropic layer.
(2) In Examples 1 to 4, the angle θA1 formed by the slow axis of the λ/2 plate (first optically anisotropic layer) in the clockwise direction with respect to the transmission axis of the linear polarizer (polarizing film) was Although an optically anisotropic laminate of 45° is shown, the present invention is not limited to this. It may be an optically anisotropic laminate having an angle of 45° between the absorption axis of the linear polarizer and the slow axis of the first optically anisotropic layer.
　１００，２００…光学異方性積層体
　１１０…第１光学異方性層
　１１１…遅相軸
　１２０…第２光学異方性層
　１２１…遅相軸
　１３０…直線偏光子
　１３１…透過軸
　５００，６００…光学異方性積層体 100, 200... Optically anisotropic laminate 110... First optical anisotropic layer 111... Slow axis 120... Second optical anisotropic layer 121... Slow axis 130... Linear polarizer 131... Transmission axis 500, 600 ... Optically anisotropic laminate

Claims (12)

  1. 　第１光学異方性層及び第２光学異方性層を含む光学異方性積層体であって、
    　前記第１光学異方性層が、下記式（１）を満たし、
    　前記第２光学異方性層が、下記式（２）を満たし、
    　前記光学異方性積層体が、下記式（３）を満たし、
    　前記第１光学異方性層のＮＺ係数ＮＺ１及び前記第２光学異方性層のＮＺ係数ＮＺ２が下記式（４）を満たし、
    　前記第１光学異方性層の遅相軸と前記第２光学異方性層の遅相軸とのなす角度が、８５°～９５°である、光学異方性積層体。
    　ｎｘ１＞ｎｙ１≧ｎｚ１　　　　　　　　　　　　　式（１）
    　ｎｚ２＞ｎｘ２＞ｎｙ２　　　　　　　　　　　　　式（２）
    　Ｒｅ（４５０）＜Ｒｅ（５５０）＜Ｒｅ（６５０）　式（３）
    　－０．３≦ＮＺ１＋ＮＺ２≦０．８　　　　　　　　式（４）
    　但し、
    　ｎｘ１は、前記第１光学異方性層の面内方向であって最大の屈折率を与える方向の屈折率を表し、ｎｙ１は、前記第１光学異方性層の面内方向であって、ｎｘ１を与える方向に直交する方向の屈折率を表し、ｎｚ１は、前記第１光学異方性層の厚み方向の屈折率を表し、
    　ｎｘ２は、前記第２光学異方性層の面内方向であって最大の屈折率を与える方向の屈折率を表し、ｎｙ２は、前記第２光学異方性層の面内方向であって、ｎｘ２を与える方向に直交する方向の屈折率を表し、ｎｚ２は、前記第２光学異方性層の厚み方向の屈折率を表し、
    　Ｒｅ（４５０）、Ｒｅ（５５０）、及びＲｅ（６５０）は、波長４５０ｎｍ、５５０ｎｍ、及び６５０ｎｍにおける前記光学異方性積層体の面内位相差をそれぞれ表す。     An optical anisotropic laminate comprising a first optical anisotropic layer and a second optical anisotropic layer,
    The first optically anisotropic layer satisfies the following formula (1),
    The second optically anisotropic layer satisfies the following formula (2),
    The optically anisotropic laminate satisfies the following formula (3),
    The NZ coefficient NZ1 of the first optically anisotropic layer and the NZ coefficient NZ2 of the second optically anisotropic layer satisfy the following formula (4),
    The optically anisotropic laminate, wherein the slow axis of the first optically anisotropic layer and the slow axis of the second optically anisotropic layer make an angle of 85° to 95°.
    nx1>ny1≧nz1 Formula (1)
    nz2>nx2>ny2 Formula (2)
    Re(450)<Re(550)<Re(650) Formula (3)
    −0.3≦NZ1+NZ2≦0.8 Formula (4)
    However,
    nx1 represents the in-plane direction of the first optically anisotropic layer and represents the refractive index in the direction that gives the maximum refractive index, and ny1 represents the in-plane direction of the first optically anisotropic layer, nx1 represents the refractive index in the direction orthogonal to the direction, and nz1 represents the refractive index in the thickness direction of the first optical anisotropic layer,
    nx2 represents a refractive index in the in-plane direction of the second optically anisotropic layer that gives the maximum refractive index, and ny2 represents an in-plane direction of the second optically anisotropic layer, nx2 represents the refractive index in the direction orthogonal to the direction, and nz2 represents the refractive index in the thickness direction of the second optically anisotropic layer,
    Re(450), Re(550), and Re(650) represent the in-plane retardation of the optically anisotropic laminate at wavelengths of 450 nm, 550 nm, and 650 nm, respectively.
  2. 　波長５５０ｎｍにおける前記第１光学異方性層の面内位相差Ｒｅ１（５５０）、
    　波長４５０ｎｍにおける前記第１光学異方性層の面内位相差Ｒｅ１（４５０）、
    　波長５５０ｎｍにおける前記第２光学異方性層の面内位相差Ｒｅ２（５５０）及び、
    　波長４５０ｎｍにおける前記第２光学異方性層の面内位相差Ｒｅ２（４５０）が、下記式（５）および式（６）を満たす、請求項１に記載の光学異方性積層体。
    　Ｒｅ１（４５０）／Ｒｅ１（５５０）＜Ｒｅ２（４５０）／Ｒｅ２（５５０）　式（５）
    　Ｒｅ１(５５０)＞Ｒｅ２(５５０)　　　式（６）     An in-plane retardation Re1(550) of the first optically anisotropic layer at a wavelength of 550 nm,
    An in-plane retardation Re1(450) of the first optically anisotropic layer at a wavelength of 450 nm,
    An in-plane retardation Re2(550) of the second optically anisotropic layer at a wavelength of 550 nm, and
    The optically anisotropic laminate according to claim 1, wherein the in-plane retardation Re2(450) of the second optically anisotropic layer at a wavelength of 450 nm satisfies the following formulas (5) and (6).
    Re1(450)/Re1(550)<Re2(450)/Re2(550) Formula (5)
    Re1(550)>Re2(550) Formula (6)
  3. 　前記Ｒｅ１（５５０）と前記Ｒｅ２（５５０）との差が、１００ｎｍ以上１８０ｎｍ以下である、請求項２に記載の光学異方性積層体。 The optically anisotropic layered product according to claim 2, wherein a difference between the Re1 (550) and the Re2 (550) is 100 nm or more and 180 nm or less.
  4. 　前記第１光学異方性層が、第１樹脂フィルムの延伸フィルムであり、
    　前記第１樹脂フィルムは、正の固有複屈折値を有する樹脂を含む、請求項１～３のいずれか１項に記載の光学異方性積層体。     The first optically anisotropic layer is a stretched film of a first resin film,
    The optically anisotropic laminate according to any one of claims 1 to 3, wherein the first resin film contains a resin having a positive intrinsic birefringence value.
  5. 　前記第１光学異方性層が、液晶配向層を含む、請求項１～４のいずれか１項に記載の光学異方性積層体。 The optically anisotropic laminate according to any one of claims 1 to 4, wherein the first optically anisotropic layer includes a liquid crystal alignment layer.
  6. 　前記第２光学異方性層が、第２樹脂フィルムの延伸フィルムであり、
    　前記第２樹脂フィルムは、負の固有複屈折値を有する樹脂を含む、請求項１～５のいずれか１項に記載の光学異方性積層体。     The second optically anisotropic layer is a stretched film of a second resin film,
    The optically anisotropic laminate according to any one of claims 1 to 5, wherein the second resin film contains a resin having a negative intrinsic birefringence value.
  7. 　前記第２光学異方性層が、前記第２樹脂フィルムを二方向延伸した延伸フィルムであり、前記ＮＺ２が－２．０以上－０．２以下である、請求項６に記載の光学異方性積層体。 7. The optically anisotropic layer according to claim 6, wherein the second optically anisotropic layer is a stretched film obtained by stretching the second resin film in two directions, and the NZ2 is −2.0 or more and −0.2 or less. Laminate.
  8. 　直線偏光子と、
    　請求項１～７のいずれか１項記載の光学異方性積層体と、を備える円偏光板。     A linear polarizer,
    A circularly polarizing plate comprising the optically anisotropic laminate according to any one of claims 1 to 7.
  9. 　前記直線偏光子の吸収軸または前記直線偏光子の透過軸と、前記第１光学異方性層の遅相軸とのなす角が４０°～５０°である、請求項８に記載の円偏光板。 The circularly polarized light according to claim 8, wherein an angle formed by an absorption axis of the linear polarizer or a transmission axis of the linear polarizer and a slow axis of the first optically anisotropic layer is 40° to 50°. Board.
  10. 　前記直線偏光子、前記第１光学異方性層、及び前記第２光学異方性層をこの順で備えるか、または、
    　前記直線偏光子、前記第２光学異方性層、及び前記第１光学異方性層をこの順で備える、請求項８または９に記載の円偏光板。     The linear polarizer, the first optically anisotropic layer, and the second optically anisotropic layer are provided in this order, or
    The circularly polarizing plate according to claim 8 or 9, comprising the linear polarizer, the second optically anisotropic layer, and the first optically anisotropic layer in this order.
  11. 　請求項８～１０のいずれか１項に記載の円偏光板と、有機エレクトロルミネッセンス素子と、を備える画像表示装置であって、
    　前記直線偏光子と、前記光学異方性積層体と、前記有機エレクトロルミネッセンス素子と、をこの順に備える、画像表示装置。     An image display device comprising the circularly polarizing plate according to any one of claims 8 to 10 and an organic electroluminescence element,
    An image display device comprising the linear polarizer, the optically anisotropic laminate, and the organic electroluminescent element in this order.
  12. 　請求項１～７のいずれか１項に記載の光学異方性積層体の製造方法であって、
    　正の固有複屈折値を有する樹脂を含む第１樹脂フィルムを延伸して第１光学異方性層を得る工程１と、
    　負の固有複屈折値を有する樹脂を含む第２樹脂フィルムを延伸して第２光学異方性層を得る工程２と、
    　前記第１光学異方性層と前記第２光学異方性層とを重ねる工程３と、を含み、
    　前記工程１において、前記第１樹脂フィルムを、一方向延伸し、
    　前記工程２において、前記第２樹脂フィルムを、二方向延伸し、
    　前記工程３において、前記第１光学異方性層の遅相軸と、前記第２光学異方性の遅相軸とのなす角が８５°～９５°となるように重ねる、光学異方性積層体の製造方法。     The method for producing an optically anisotropic laminate according to any one of claims 1 to 7,
    Step 1 of stretching a first resin film containing a resin having a positive intrinsic birefringence value to obtain a first optically anisotropic layer,
    Step 2 of stretching a second resin film containing a resin having a negative intrinsic birefringence value to obtain a second optically anisotropic layer,
    A step 3 of stacking the first optically anisotropic layer and the second optically anisotropic layer,
    In the step 1, the first resin film is unidirectionally stretched,
    In the step 2, the second resin film is bidirectionally stretched,
    In the step 3, the optical anisotropy is overlapped so that an angle formed by the slow axis of the first optical anisotropic layer and the slow axis of the second optical anisotropy is 85° to 95°. Method for manufacturing laminated body.
PCT/JP2019/047519 2018-12-27 2019-12-04 Optically anisotropic laminate, method for manufacturing same, circularly polarizing plate, and image display device WO2020137409A1 (en)

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TW202027970A (en) 2020-08-01

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