Optical anisotropic laminates and their manufacturing methods, circular polarizers, and image display devices

Abstract

This invention provides an optically anisotropic laminate comprising a first optically anisotropic layer and a second optically anisotropic layer. The first optically anisotropic layer satisfies the following equation (1), the second optically anisotropic layer satisfies the following equation (2), the optically anisotropic laminate satisfies the following equation (3), the NZ coefficients NZ1 of the first optically anisotropic layer and NZ2 of the second optically anisotropic layer satisfy the following equation (4), and the angle between the slow axis of the first optically anisotropic layer and the slow axis of the second optically anisotropic layer is 90°. nx1>ny1≥nz1 Equation (1) nz2>nx2>ny2 Equation (2) Re(450)<Re(550)<Re(650) Equation (3)-0.3≤NZ1+NZ2≤0.8 Equation (4)

Description

Technical Field

[0001] This invention relates to optical anisotropic laminates and their manufacturing methods, circular polarizers, and image display devices. Background Technology

[0002] Image display devices, such as organic electroluminescent image display devices, sometimes suffer from degraded image quality due to reflection of external light. Hereinafter, organic electroluminescence will sometimes be referred to as "organic EL". Particularly in the case of organic EL image display devices with reflective electrodes, the image display quality is significantly reduced. To suppress such reflection, a circular polarizer is sometimes provided on the display surface of the image display device (see, for example, Patent Document 1).

[0003] External light rays are converted into circularly polarized light in a certain direction by a circular polarizer. When reflected by the image display device, they become circularly polarized light in the opposite direction. The reflected light of this oppositely polarized light does not pass through the circular polarizer, thus suppressing reflection.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese International Publication No. 2016 / 047465;

[0007] Patent Document 2: Japanese Patent Application Publication No. 2010-266723. Summary of the Invention

[0008] The problem the invention aims to solve

[0009] Patent Document 1 describes a method to effectively suppress reflection by having a circular polarizer with the following structure: the circular polarizer has a linear polarizer, a λ / 2 waveplate having a slow axis in a direction at a predetermined angle to the absorption axis of the linear polarizer, and a λ / 4 waveplate having a slow axis in a direction at a predetermined angle to the absorption axis of the linear polarizer. The wavelength dispersion of the λ / 2 waveplate is different from that of the λ / 4 waveplate, and the NZ coefficient of the λ / 4 waveplate is a predetermined value.

[0010] However, even when such a circular polarizer is provided on the display surface of the image display device, when the display surface is viewed from an oblique direction, reflected light can sometimes be seen on the display surface, and thus the display surface will be observed to be colored.

[0011] Furthermore, Reference 2 describes how a λ / 4 waveplate, fabricated by stacking a linear polarizer and two stretched films in a parallel manner along the slow axis, can suppress reflection by setting the NZ coefficient to a specified value.

[0012] However, when such a circular polarizer is provided on the display surface of an image display device, the reflection effect is not sufficiently suppressed when the display surface is viewed from the front and tilted directions, and sometimes the display surface is observed to be tinted.

[0013] Therefore, there is still a need for an optical anisotropic laminate for an image display device that can suppress the coloration of the display surface when viewed from an oblique direction, and a method for manufacturing the same; a circular polarizer for an image display device that can suppress the coloration of the display surface when viewed from an oblique direction; and an image display device that can suppress the coloration of the display surface when viewed from an oblique direction.

[0014] Solution for solving the problem

[0015] To address the aforementioned problems, the inventors conducted in-depth research and discovered that the problems can be solved by using an optical anisotropic stack comprising a first optical anisotropic layer satisfying specified optical conditions and a second optical anisotropic layer satisfying specified optical conditions, wherein the sum of the NZ coefficients NZ1 of the first optical anisotropic layer and NZ2 of the second optical anisotropic layer is within a specified range, and the slow axis of the first optical anisotropic layer and the slow axis of the second optical anisotropic layer are orthogonal. This invention thus completes the present invention. Specifically, the present invention provides the following:

[0016] [1] An optically anisotropic laminate, comprising a first optically anisotropic layer and a second optically anisotropic layer,

[0017] The aforementioned first optical anisotropic layer satisfies the following equation (1),

[0018] The aforementioned second optical anisotropic layer satisfies the following equation (2),

[0019] The above-mentioned optically anisotropic laminate satisfies the following equation (3),

[0020] The NZ coefficients NZ1 of the first optical anisotropic layer and NZ2 of the second optical anisotropic layer satisfy the following equation (4).

[0021] The angle between the slow axis of the first optical anisotropy layer and the slow axis of the second optical anisotropy layer is 85° to 95°.

[0022] nx1>ny1≥nz1 Equation (1)

[0023] Equation (2) is: nz² > nx² > ny²

[0024] Re(450)<Re(550)<Re(650) Formula (3)

[0025] -0.3≤NZ1+NZ2≤0.8 Equation (4)

[0026] in,

[0027] nx1 represents the refractive index in the direction providing the maximum refractive index in the in-plane direction of the first optical anisotropic layer, ny1 represents the refractive index in the direction orthogonal to the direction providing nx1 in the in-plane direction of the first optical anisotropic layer, and nz1 represents the refractive index in the thickness direction of the first optical anisotropic layer.

[0028] nx2 represents the refractive index in the direction providing the maximum refractive index in the in-plane direction of the second optical anisotropy layer, ny2 represents the refractive index in the in-plane direction of the second optical anisotropy layer that is orthogonal to the direction providing nx2, and nz2 represents the refractive index in the thickness direction of the second optical anisotropy layer.

[0029] Re(450), Re(550), and Re(650) represent the in-plane phase differences of the aforementioned optical anisotropic laminate at wavelengths of 450 nm, 550 nm, and 650 nm, respectively.

[0030] [2] According to the optically anisotropic laminate described in [1], wherein,

[0031] The in-plane phase difference Re1(550) of the first optical anisotropic layer at a wavelength of 550 nm

[0032] The in-plane phase difference Re1(450) of the first optical anisotropic layer at a wavelength of 450 nm

[0033] The in-plane phase difference Re2(550) of the aforementioned second optical anisotropic layer at a wavelength of 550 nm

[0034] The in-plane phase difference Re2(450) of the second optical anisotropic layer at a wavelength of 450 nm satisfies the following equations (5) and (6).

[0035] Re1(450) / Re1(550)<Re2(450) / Re2(550) Equation (5)

[0036] Re1(550)>Re2(550) Equation (6)

[0037] [3] According to the optical anisotropic laminate described in [2], wherein,

[0038] The difference between Re1(550) and Re2(550) is greater than 100nm and less than 180nm.

[0039] [4] An optically anisotropic laminate according to any one of [1] to [3], wherein,

[0040] The aforementioned first optical anisotropic layer is a stretched film of the first resin film.

[0041] The first resin film mentioned above contains a resin having a positive intrinsic birefringence value.

[0042] [5] An optically anisotropic laminate according to any one of [1] to [4], wherein,

[0043] The aforementioned first optical anisotropy layer includes a liquid crystal alignment layer.

[0044] [6] An optically anisotropic laminate according to any one of [1] to [5], wherein,

[0045] The aforementioned second optical anisotropic layer is a stretched film of the second resin film.

[0046] The aforementioned second resin film comprises a resin having a negative intrinsic birefringence value.

[0047] [7] According to the optically anisotropic laminate described in [6], wherein,

[0048] The aforementioned second optical anisotropic layer is a stretched film obtained by stretching the aforementioned second resin film in two directions, wherein the aforementioned NZ2 is greater than or equal to -2.0 and less than or equal to -0.2.

[0049] [8] A circular polarizer, comprising:

[0050] Linear polarizer; and

[0051] Optical anisotropic laminates as described in any one of [1] to [7].

[0052] [9] According to the circular polarizer described in [8], wherein,

[0053] The angle between the absorption axis or transmission axis of the linear polarizer and the slow axis of the first optical anisotropy layer is 40° to 50°.

[0054]

[10] According to the circular polarizer described in [8] or [9], wherein,

[0055] The aforementioned circular polarizer sequentially comprises the aforementioned linear polarizer, the aforementioned first optical anisotropic layer, and the aforementioned second optical anisotropic layer, or

[0056] The aforementioned circular polarizer sequentially comprises the aforementioned linear polarizer, the aforementioned second optical anisotropic layer, and the aforementioned first optical anisotropic layer.

[0057]

[11] An image display device comprising a circular polarizer and an organic electroluminescent element as described in any one of [8] to

[10] ,

[0058] The image display device described above sequentially includes the linear polarizer, the optical anisotropic laminate, and the organic electroluminescent element.

[0059]

[12] A method for manufacturing an optically anisotropic laminate, which is the method for manufacturing an optically anisotropic laminate according to any one of claims 1 to 7, includes the following steps:

[0060] Step 1: Stretch a first resin film containing a resin with a positive intrinsic birefringence value to obtain a first optical anisotropy layer.

[0061] Step 2 involves stretching a second resin film containing a resin having a negative intrinsic birefringence value to obtain a second optically anisotropic layer; and

[0062] Step 3 involves overlapping the first optical anisotropic layer and the second optical anisotropic layer.

[0063] In step 1 above, the first resin film is stretched in one direction.

[0064] In step 2 above, the second resin film is stretched in two directions.

[0065] In step 3 above, the slow axis of the first optical anisotropy layer and the slow axis of the second optical anisotropy layer are overlapped in such a way that the angle between them is 85° to 95°.

[0066] Invention Effects

[0067] According to the present invention, it is possible to provide: an optical anisotropic laminate capable of realizing an image display device that can suppress the coloring of the display surface when viewed from an oblique direction, and a method for manufacturing the same; a circular polarizer capable of realizing an image display device that can suppress the coloring of the display surface when viewed from an oblique direction; and an image display device capable of suppressing the coloring of the display surface when viewed from an oblique direction. Attached Figure Description

[0068] Figure 1 This is an exploded perspective view schematically representing the circular polarizer of Embodiment 1.

[0069] Figure 2 This is an exploded perspective view schematically representing the circular polarizer of Embodiment 2.

[0070] Figure 3 This is a perspective view schematically representing the state of the evaluation model set during chromaticity calculation in the simulations of the embodiments and comparative examples. Detailed Implementation

[0071] The present invention will now be described in detail with reference to embodiments and examples. However, the present invention is not limited to the embodiments and examples shown below, and any modifications can be made to implement it without departing from the scope of the claims of the present invention and its equivalents.

[0072] In the following description, "strip" film refers to a film having a length that is 5 times or more relative to its width, preferably 10 times or more, specifically meaning a length sufficient to be rolled up for storage or transport. There is no particular upper limit to the length of strip film; for example, it can be less than 100,000 times its width.

[0073] In the following description, unless otherwise specified, the in-plane phase difference Re of a layer is represented by Re = (nx - ny) × d. Unless otherwise specified, the phase difference Rth in the thickness direction of a layer is represented by Rth = {(nx + ny) / 2 - nz} × d. Furthermore, unless otherwise specified, the NZ coefficient (NZ) of a layer is represented by NZ = (nx - nz) / (nx - ny). The NZ coefficient can be calculated by NZ = Rth / Re + 0.5.

[0074] Here, nx represents the refractive index in the direction (slow axis direction) that provides the maximum refractive index in the direction perpendicular to the thickness direction of the layer (in-plane direction); ny represents the refractive index in the direction orthogonal to the nx direction in the aforementioned 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. Unless otherwise specified, the measurement wavelength is 590 nm.

[0075] In the following description, unless otherwise specified, the slow axis of a layer refers to the slow axis within the plane of that layer.

[0076] In the following description, unless otherwise stated, the frontal direction of a face means the direction of the normal to that face, specifically the direction where the polar angle and azimuth angle of the face are both 0°.

[0077] In the following description, unless otherwise stated, the direction of inclination of a surface refers to the direction that is neither parallel nor perpendicular to the surface, specifically the direction in which the polar angle of the surface is greater than 0° and less than 90°.

[0078] In the following description, unless otherwise stated, the orientation of elements as “parallel,” “perpendicular,” and “orthogonal” may include errors within, for example, a range of ±1 / 2 without impairing the effectiveness of the invention.

[0079] In the following description, the length direction of the elongated membrane is usually parallel to the flow direction of the membrane on the production line.

[0080] In the following description, unless otherwise stated, “polarizer,” “circular polarizer,” “plate,” and “λ / 2 waveplate” and “λ / 4 waveplate” include not only rigid components but also flexible components such as resin films.

[0081] In the following description, unless otherwise stated, the angle formed by the optical axes (absorption axis, transmission axis, slow axis, etc.) of each layer in a component with multiple layers represents the angle when the layer is viewed from the thickness direction.

[0082] In the following description, "polymer with positive intrinsic birefringence" and "resin with positive intrinsic birefringence" refer to "polymers whose refractive index in the stretching direction is greater than that in the direction orthogonal to the stretching direction" and "resins whose refractive index in the stretching direction is greater than that in the direction orthogonal to the stretching direction," respectively. Similarly, "polymer with negative intrinsic birefringence" and "resin with negative intrinsic birefringence" refer to "polymers whose refractive index in the stretching direction is smaller than that in the direction orthogonal to the stretching direction" and "resins 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 based on the dielectric constant distribution.

[0083] In the following description, unless otherwise stated, adhesives include not only adhesives in the narrow sense, but also adhesives with a shear storage modulus of less than 1 MPa at 23°C. Adhesives in the narrow sense refer to adhesives with a shear storage modulus of 1 MPa to 500 MPa at 23°C after irradiation with energy rays or heat treatment.

[0084] [Implementation Method 1]

[0085] The following is for reference. Figure 1 The circular polarizer of Embodiment 1 of the present invention and the image display device having the circular polarizer will be described. Figure 1 This is an exploded perspective view schematically representing the circular polarizer of Embodiment 1.

[0086] like Figure 1 As shown, the circular polarizer 500 of this embodiment has a linear polarizer 130 and an optical anisotropic laminate 100 of this embodiment.

[0087] [1. Optically anisotropic laminates]

[0088] [1-1. Structure of Optical Anisotropic Laminates]

[0089] The optical anisotropic laminate 100 of this embodiment includes a first optical anisotropic layer 110 and a second optical anisotropic layer 120. The optical anisotropic laminate 100 may also have any number of layers (not shown) as needed.

[0090] In this embodiment, the first optical anisotropic layer 110 satisfies the following formula (1), the second optical anisotropic layer 120 satisfies the following formula (2), the optical anisotropic laminate 100 satisfies the following formula (3), the first optical anisotropic layer and the second optical anisotropic layer satisfy the following formula (4), and the angle between the slow axis 111 of the first optical anisotropic layer 110 and the slow axis 121 of the second optical anisotropic layer 120 is 85° to 95°.

[0091] A circular polarizer 500 is obtained by combining an optical anisotropic laminate 100 having optical properties that satisfy equations (1) to (4) and an angle of 85° to 95° between the slow axis 111 of the first optical anisotropic layer 110 and the slow axis 121 of the second optical anisotropic layer 120 and a linear polarizer 130. When such a circular polarizer 500 is installed in an image display device, the reflection of external light can be suppressed when the display surface of the image display device is viewed from an inclined direction, thereby effectively suppressing color distortion.

[0092] nx1>ny1≥nz1 Equation (1)

[0093] Equation (2) is: nz² > nx² > ny²

[0094] Re(450)<Re(550)<Re(650) Formula (3)

[0095] -0.3≤NZ1+NZ2≤0.8 Equation (4)

[0096] In the above equation (1), nx1 represents the refractive index of the direction in which the maximum refractive index is provided in the in-plane direction of the first optical anisotropic layer; ny1 represents the refractive index of the direction in which the maximum refractive index is provided in the in-plane direction of the first optical anisotropic layer; and nz1 represents the refractive index of the thickness direction of the first optical anisotropic layer.

[0097] Equation (1) above indicates that the first optical anisotropy layer can function as a so-called positive A plate or a negative B plate.

[0098] Because a material with high heat resistance can be used as the material for the layer that satisfies the above formula (1), by using such a material as the material for the first optical anisotropy layer, it is easy to realize an image display device that can suppress color changes of the display surface after a heating test.

[0099] In the above equation (2), nx2 represents the refractive index of the direction that provides the maximum refractive index in the in-plane direction of the second optical anisotropic layer; ny2 represents the refractive index of the direction orthogonal to the direction that provides nx2 in the in-plane direction of the second optical anisotropic layer; and nz2 represents the refractive index of the thickness direction of the second optical anisotropic layer.

[0100] Equation (2) above indicates that the second optical anisotropic layer can function as a so-called positive B plate. By making the second optical anisotropic layer satisfy equation (2), an image display device that can effectively suppress coloration caused by reflected light can be realized. Equation (2) indicates that the second optical anisotropic layer is a layer with different refractive indices (nx2, ny2, and nz2) in three directions, that is, a layer with biaxiality.

[0101] In the above equation (3), Re(450), Re(550) and Re(650) represent the in-plane phase differences of the optical anisotropic laminate at wavelengths of 450 nm, 550 nm and 650 nm, respectively.

[0102] Equation (3) above indicates that the in-plane phase difference of the optical anisotropic laminate exhibits anti-wavelength dispersion. By making the optical anisotropic laminate satisfy Equation (3), the polarization state of light transmitted through the optical anisotropic laminate can be uniformly converted over a wide wavelength range. Therefore, it is possible to realize an image display device that can effectively suppress coloration caused by reflected light over a wide wavelength range.

[0103] In equation (4) above, NZ1 represents the NZ coefficient of the first optical anisotropy layer, and NZ2 represents the NZ coefficient of the second optical anisotropy 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. By controlling the sum of NZ1 and NZ2 within the above range, an image display device that can effectively suppress coloration caused by reflected light when viewing the display surface from an inclined direction can be realized.

[0104] NZ1 is a value calculated from (nx1-nz1) / (nx1-ny1). As can be seen from equation (1), NZ1 is a positive value. NZ1 is preferably 1.0 or more, more preferably 1.05 or more, and preferably 1.3 or less, more preferably 1.2 or less.

[0105] NZ2 is a value calculated from (nx2-nz2) / (nx2-ny2), and as shown in equation (2), NZ2 is a negative value. NZ2 is preferably -2.0 or higher, more preferably -1.5 or higher, and preferably -0.2 or lower, more preferably -0.4 or lower. By controlling NZ2 within the above range, biaxiality can be improved.

[0106] The first optical anisotropic layer and the second optical anisotropic layer preferably have optical properties that satisfy the following equations (5) and (6).

[0107] Re1(450) / Re1(550)<Re2(450) / Re2(550) Equation (5)

[0108] Re1(550)>Re2(550) Equation (6)

[0109] In equation (5) above, Re1(550) represents the in-plane phase difference of the first optical anisotropic layer at a wavelength of 550 nm, Re1(450) represents the in-plane phase difference of the first optical anisotropic layer at a wavelength of 450 nm, Re2(550) represents the in-plane phase difference of the second optical anisotropic layer at a wavelength of 550 nm, and Re2(450) represents the in-plane phase difference of the second optical anisotropic layer at a wavelength of 450 nm.

[0110] Equation (5) above indicates that the wavelength dispersion is greater in the second optical anisotropic layer than in the first optical anisotropic layer.

[0111] In equation (6) above, Re1(550) represents the in-plane phase difference of the first optical anisotropic layer at a wavelength of 550 nm, and Re2(550) represents the in-plane phase difference of the second optical anisotropic layer at a wavelength of 550 nm. Equation (6) indicates that Re1(550) of the first optical anisotropic layer is larger than Re2(550) of the second optical anisotropic layer.

[0112] The difference between Re1 (550) and Re2 (550) is preferably 100 nm or more, more preferably 110 nm or more, and preferably 180 nm or less, more preferably 160 nm or less.

[0113] The in-plane phase difference Re1(590) of the first optical anisotropic layer at a wavelength of 590 nm is preferably 240 nm or more, more preferably 260 nm or more, and preferably 320 nm or less, more preferably 300 nm or less. By keeping the in-plane phase difference Re1(590) of the first optical anisotropic layer within the above range, it is possible to realize an image display device that can more effectively suppress coloration caused by reflected light when viewing the display surface from an oblique direction.

[0114] The in-plane phase difference Re2 (590) of the second optical anisotropic layer at a wavelength of 590 nm is preferably 100 nm or more, more preferably 120 nm or more, and preferably 190 nm or less, more preferably 170 nm or less. By making the in-plane phase difference Re2 (590) of the second optical anisotropic layer within the above range, it is possible to realize an image display device that can more effectively suppress coloration caused by reflected light when viewing the display surface from an inclined direction.

[0115] The total transmittance of the first optical anisotropic layer is preferably 80% or more, more preferably 85% or more, and particularly preferably 90% or more.

[0116] The total transmittance of the second optical anisotropic layer is preferably 80% or more, more preferably 85% or more, and particularly preferably 90% or more.

[0117] The haze of the first optical anisotropic layer is preferably 5% or less, more preferably 3% or less, particularly preferably 1% or less, and ideally 0%.

[0118] The haze of the second optical anisotropic layer is preferably 5% or less, more preferably 3% or less, particularly preferably 1% or less, and ideally 0%.

[0119] The thickness of the first optical anisotropic layer and the thickness of the second optical anisotropic layer can be arbitrarily adjusted within the range of the aforementioned optical properties.

[0120] The thickness of the first optical anisotropic layer is preferably 0.5 μm or more, more preferably 1 μm or more, and preferably 150 μm or less, more preferably 100 μm or less.

[0121] The thickness of the second optical anisotropic layer is preferably 0.5 μm or more, more preferably 1 μm or more, and preferably 150 μm or less, more preferably 100 μm or less.

[0122] The total transmittance of the optically anisotropic laminate is preferably 80% or more, more preferably 85% or more, and particularly preferably 90% or more.

[0123] 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%.

[0124] The thickness of the optically anisotropic laminate can be arbitrarily adjusted within the range of the aforementioned optical properties. From the viewpoint of thinness, the specific thickness is preferably 5 μm or more, more preferably 10 μm or more, particularly preferably 15 μm or more, and preferably 200 μm or less, more preferably 150 μm or less, and particularly preferably 100 μm or less.

[0125] [1-2. Materials of the first and second optical anisotropic layers]

[0126] Examples of materials used to form the first and second optical anisotropic layers include resins, with thermoplastic resins being preferred.

[0127] The material used to form the first optical anisotropic layer and the second optical anisotropic layer can be a resin containing a polymer having a positive intrinsic birefringence value, a resin containing a polymer having a negative intrinsic birefringence value, or a resin containing both a polymer having a positive intrinsic birefringence value and a polymer having a negative intrinsic birefringence value.

[0128] Polymers with positive intrinsic birefringence are not particularly limited, but can include, for example, polyolefins such as polyethylene and polypropylene; polyesters such as polyethylene terephthalate and polybutylene terephthalate; polyarylene sulfides such as polyphenylene sulfide; polyvinyl alcohol; polycarbonate; polyarylene esters; cellulose esters; polyethersulfone; polysulfone; polyarylene sulfone; polyvinyl chloride; cyclic olefin polymers; polymers containing alicyclic structures such as norbornene polymers; and rod-shaped liquid crystal polymers.

[0129] The polymer having a negative intrinsic birefringence value is not particularly limited, and examples include, for instance, homopolymers containing styrene compounds, and polystyrene-based polymers, copolymers of styrene compounds with any monomer; polyacrylonitrile polymers; polymethyl methacrylate polymers; or multi-component copolymers thereof. Furthermore, as any of the aforementioned monomers capable of copolymerizing with styrene compounds, examples include acrylonitrile, maleic anhydride, methyl methacrylate, and butadiene, preferably selected from one or more of acrylonitrile, maleic anhydride, methyl methacrylate, and butadiene.

[0130] The polymers mentioned above can be homopolymers or copolymers.

[0131] Furthermore, the aforementioned polymers can be used alone or in combination of two or more in any ratio.

[0132] In addition to the polymers described above, the resins used to form the first and second optically anisotropic layers may also contain any additives. Examples of additives include antioxidants, heat stabilizers, light stabilizers, weather stabilizers, ultraviolet absorbers, near-infrared absorbers, and plasticizers. One type of additive may be used, or two or more additives may be used in any combination.

[0133] The first optical anisotropic layer may also be a layer that includes a liquid crystal alignment layer. The liquid crystal alignment layer will be explained in [1-3-2].

[0134] [1-3. Preferred materials for the first optical anisotropy layer]

[0135] [1-3-1. Resin with positive intrinsic birefringence]

[0136] The first optical anisotropy layer can be a stretched film of the first resin film. The first resin film preferably comprises a resin having a positive intrinsic birefringence. Examples of such a resin having a positive intrinsic birefringence include resins containing alicyclic polymers, resins containing cellulose esters, and resins containing polycarbonates. More preferably, the first resin film comprises one or more resins selected from resins containing alicyclic polymers, resins containing cellulose esters, and resins containing polycarbonates; even more preferably, it comprises a resin containing alicyclic polymers. By using a resin having a positive intrinsic birefringence as the material, the first optical anisotropy layer satisfying formula (1) can be easily manufactured by stretching the first resin film formed from this resin. The first optical anisotropy layer can be a layer formed by stretching a film (first resin film) formed from a resin having a positive intrinsic birefringence. The first resin film is the resin film before stretching to form the first optical anisotropy layer.

[0137] Alicyclic polymers are polymers that have an alicyclic structure in repeating units, and are typically amorphous polymers. As alicyclic polymers, either polymers containing an alicyclic structure in the main chain or polymers containing an alicyclic structure in the side chains can be used.

[0138] Examples of alicyclic structures include cycloalkane structures and cycloolefin structures. From the perspective of thermal stability, cycloalkane structures are preferred.

[0139] There is no particular limitation on the number of carbon atoms in the repeating unit constituting an alicyclic structure, but it is preferably 4 or more, more preferably 5 or more, particularly preferably 6 or more, and preferably 30 or less, more preferably 20 or less, and particularly preferably 15 or less.

[0140] The proportion of repeating units with alicyclic structures in the polymer containing alicyclic structures can be appropriately selected according to the intended use, preferably 50% by weight or more, more preferably 70% by weight or more, and particularly preferably 90% by weight or more. By making the number of repeating units with alicyclic structures as described above, the heat resistance of the first optical anisotropy layer can be improved.

[0141] Examples of alicyclic polymers include (1) norbornene polymers, (2) monocyclic cyclic olefin polymers, (3) cyclic conjugated diene polymers, and (4) vinyl alicyclic hydrocarbon polymers and their hydrogenated derivatives. Among these, cyclic olefin polymers and norbornene polymers are more preferred.

[0142] Examples of norbornene polymers include, for instance, ring-opening polymers of norbornene monomer, ring-opening copolymers of norbornene monomer with other monomers capable of ring-opening copolymerization, and their hydrogenated derivatives; addition polymers of norbornene monomer, addition copolymers of norbornene monomer with other monomers capable of copolymerization, etc. Among these, hydrogenated derivatives of ring-opening polymers of norbornene monomer are particularly preferred from the viewpoint of transparency.

[0143] The aforementioned polymers containing alicyclic structures are selected from known polymers disclosed, such as Japanese Patent Application Publication No. 2002-321302.

[0144] As cellulose esters, representative examples include lower fatty acid esters of cellulose (e.g., cellulose acetate, cellulose acetate butyrate, and cellulose acetate propionate). Lower fatty acids are fatty acids with 6 or fewer carbon atoms per molecule. Cellulose acetate includes cellulose triacetate (TAC) and cellulose diacetate (DAC).

[0145] The total acyl substitution degree of the cellulose ester is preferably 2.20 or more and 2.70 or less, more preferably 2.40 or more and 2.60 or less. Here, the total acyl group can be determined according to ASTM D817-91.

[0146] 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.

[0147] Polycarbonates can be exemplified by polymers having structural units derived from dihydroxy compounds and carbonate structures (represented by -O-(C=O)-O-).

[0148] Examples of dihydroxy compounds include bisphenol A. Polycarbonate may contain one or more structural units derived from dihydroxy compounds.

[0149] The first optical anisotropy layer preferably comprises a resin containing cellulose triacetate. The film formed from the cellulose triacetate resin generally exhibits retardation due to its anti-wavelength dispersion, thus enabling an image display device that can more effectively suppress coloration caused by reflected light over a wide wavelength range.

[0150] When the first optical anisotropic layer is formed from a resin containing cellulose triacetate, it is preferable that the first optical anisotropic layer is formed by solution casting. Thus, the first optical anisotropic layer satisfying formula (1) can be easily manufactured.

[0151] [1-3-2. Liquid Crystal Alignment Layer]

[0152] The first optical anisotropy layer can be a layer containing a liquid crystal alignment layer.

[0153] The liquid crystal alignment layer is a cured layer formed by curing a layer of a liquid crystal composition containing an aligned liquid crystal compound. Therefore, the liquid crystal alignment layer is formed from the cured liquid crystal composition and thus contains molecules of the liquid crystal compound.

[0154] The liquid crystal compound preferably possesses polymerizability. Therefore, the liquid crystal compound preferably contains polymerizable groups such as acryloyl, methacryl, and epoxy groups in its molecules. Each molecule of the liquid crystal compound may have one polymerizable group, but preferably two or more. The polymerizable liquid crystal compound, when polymerized in a liquid crystal phase, can become a polymer in which the direction of maximum refractive index does not change within the refractive index ellipsoid of the molecules in the liquid crystal phase. This allows the alignment state of the liquid crystal compound to be fixed in the liquid crystal alignment layer, or it allows the mechanical strength of the liquid crystal alignment layer to be improved by increasing the polymerizability of the liquid crystal compound.

[0155] The molecular weight of the liquid crystal compound is preferably 300 or more, more preferably 500 or more, particularly preferably 800 or more, and more preferably 2000 or less, more preferably 1700 or less, and particularly preferably 1500 or less. Using a liquid crystal compound with a molecular weight within this range results in particularly good coatability of the liquid crystal composition.

[0156] The birefringence Δn of the liquid crystal compound measured at a wavelength of 590 nm is preferably 0.01 or more, more preferably 0.03 or more, and more preferably 0.15 or less, more preferably 0.10 or less. When using a liquid crystal compound with such a range of birefringence Δn, it is easy to obtain a liquid crystal cured layer with fewer orientation defects.

[0157] Liquid crystal compounds can be used alone or in combination of two or more in any ratio.

[0158] As an example of such a liquid crystal compound, the liquid crystal compound represented by the following formula (I) can be cited.

[0159] [Chemical Formula 1]

[0160]

[0161] In formula (I), Ar represents a divalent organic group having at least one of an aromatic heterocycle, a heterocycle, or an aromatic hydrocarbon ring, and having 6 to 67 substituted carbon atoms. Examples of aromatic heterocycles include, for example, 1H-isoindole-1,3(2H)-dione rings, 1-benzofuran rings, 2-benzofuran rings, acridine rings, isoquinoline rings, imidazole rings, indole rings, oxadiazole rings, oxazole rings, oxazolopyrazine rings, oxazolopyridine rings, oxazolopyridazine rings, oxazolopyrimidine rings, quinazolopyrimidine rings, quinazolopyrimidine rings, quinazolopyrimidine rings, quinazolopyrimidine rings, thiazoline rings, thiazoline rings, thiazopyrazine rings, thiazopyridazine rings, and thiazopyridazine rings. Pyrimidine rings, thiophene rings, triazine rings, triazole rings, diazanaphthalene rings, pyrazine rings, pyrazole rings, pyranone rings, pyran rings, pyridine rings, pyridazine rings, pyrimidine rings, pyrrole rings, phenanthridine rings, phthalazine rings, furan rings, benzo[c]thiophene rings, benzo[s]isoxazole rings, benzo[s]isothiazole rings, benzo[s]imidazolium rings, benzo[s]oxadiazole rings, benzo[s]oxadiazole rings, benzo[s]thiadiazole rings, benzo[s]thiazolium rings, benzo[s]thiophene rings, benzo[s]triazine rings, benzo[s]triazole rings, benzo[s]pyrazole rings, and benzo[s]pyranone rings are all examples of heterocycles. Examples of heterocycles include 1,3-dithiopentane, pyrrolidine, and piperazine. Examples of aromatic hydrocarbon rings include benzene rings and naphthyl rings.

[0162] In equation (I), Z 1 and Z 2 Each can be independently represented by a single bond, -O-, -O-CH2-, -CH2-O-, -O-CH2-CH2-, -CH2-CH2-O-, -C(=O)-O-, -OC(=O)-, -C(=O)-S-, -SC(=O)-, -NR 21 -C(=O)-、-C(=O)-NR 21 -, -CF2-O-, -O-CF2-, -CH2-CH2-, -CF2-CF2-, -O-CH2-CH2-O-, -CH=CH-C(=O)-O-, -OC(=O)-CH=CH-, -CH2-C(=O)-O-, -OC(=O)-CH2-, -CH2-OC(=O-, -C(=O)-O-CH2-, -CH2-CH2-C(=O)-O-, -OC(=O)-CH2-CH2-, -CH2-CH2-OC(=O-, -C(=O)-O-CH2-CH2-, -CH=CH-, -N=CH-, -CH=N-, -N=C(CH3)-, -C(CH3)=N-, -N=N-, and -C=N- any one of these. R 21 Each can be independently represented as an alkyl group having 1 to 6 hydrogen atoms or carbon atoms.

[0163] In equation (I), A 1 A 2 B1 and B 2 Each of these groups independently represents a group selected from cyclic aliphatic groups that may have substituents and aromatic groups that may have substituents. A 1 A 2 B 1 and B 2 The number of carbon atoms in each group (including the number of carbon atoms in substituents) is independent, typically ranging from 3 to 100. Among them, A... 1 A 2 B 1 And B 2 Each may independently be a cyclic aliphatic group having 5 to 20 carbon atoms with substituents, or an aromatic group having 2 to 20 carbon atoms with substituents.

[0164] As A 1 A 2 B 1 And B 2 Examples of cyclic aliphatic groups include cycloalkyldiyl groups with 5 to 20 carbon atoms, such as cyclopentane-1,3-diyl, cyclohexane-1,4-diyl, cycloheptane-1,4-diyl, and cyclooctane-1,5-diyl; and dicycloalkyldiyl groups with 5 to 20 carbon atoms, such as decahydronaphthalene-1,5-diyl and decahydronaphthalene-2,6-diyl. Preferably, cycloalkyldiyl groups with 5 to 20 carbon atoms that can be substituted are substituted; more preferably, cyclohexanediyl groups are substituted; and particularly preferably, cyclohexane-1,4-dialkyl groups are substituted. The cyclic aliphatic group can be trans, cis, or a mixture of cis and trans. The trans form is preferred.

[0165] As A 1 A 2 B 1 And B 2 Examples of substituents in the cyclic aliphatic group include halogen atoms, alkyl groups with 1 to 6 carbon atoms, alkoxy groups with 1 to 5 carbon atoms, nitro groups, and cyano groups. There can be one or more substituents. Furthermore, the substituents can be identical or different from each other.

[0166] As A 1 A 2 B 1 And B 2Examples of aromatic groups in this formulation include aromatic hydrocarbon cyclic groups with 6 to 20 carbon atoms, such as 1,2-phenylene, 1,3-phenylene, 1,4-phenylene, 1,4-naphthylene, 1,5-naphthylene, 2,6-naphthylene, and 4,4'-biphenylene; and aromatic heterocyclic groups with 2 to 20 carbon atoms, such as furan-2,5-diyl, thiophene-2,5-diyl, pyridine-2,5-diyl, and pyrazine-2,5-diyl. Among these, aromatic hydrocarbon cyclic groups with 2 to 20 carbon atoms are preferred, phenylene is more preferred, and 1,4-phenylene is particularly preferred.

[0167] As A 1 A 2 B 1 And B 2 The aromatic groups in the aromatic group may have substituents, for example, those with A 1 A 2 B 1 And B 2 Examples of cyclic aliphatic groups having the same substituents. The number of substituents can be one or more. Furthermore, multiple substituents can be the same as or different from each other.

[0168] In equation (I), Y 1 ~Y 4 Each can be independently represented by a single bond, -O-, -C(=O)-, -C(=O)-O-, -OC(=O)-, or -NR. 22 -C(=O)-、-C(=O)-NR 22 -、-OC(=O)-O-、-NR 22 -C(=O)-O-、-OC(=O)-NR 22 -and-NR 22 -C(=O)-NR 23 Any one of - . R 22 and R 23 Each can be independently represented as an alkyl group having 1 to 6 hydrogen atoms or carbon atoms.

[0169] In equation (I), G 1 and G 2 Each of these groups independently represents an organic group selected from aliphatic hydrocarbon groups having 1 to 20 carbon atoms; and from aliphatic hydrocarbon groups having 3 to 20 carbon atoms, where one or more methylene (-CH2-) groups are substituted with -O- or -C(=O)-. G 1 and G 2 The hydrogen atoms contained in the aforementioned organic groups can be replaced by alkyl groups having 1 to 5 carbon atoms, alkoxy groups having 1 to 5 carbon atoms, or halogen atoms. However, G 1 and G 2The methylene groups (-CH2-) at both ends are not replaced by -O- or -C(=O)-.

[0170] As G 1 and G 2 Specific examples of aliphatic hydrocarbon groups with 1 to 20 carbon atoms include alkylene groups with 1 to 20 carbon atoms.

[0171] As G 1 and G 2 Specific examples of aliphatic hydrocarbon groups with 3 to 20 carbon atoms include alkylene groups with 3 to 20 carbon atoms.

[0172] In equation (I), P 1 and P 2 Each independently represents a polymerizable group. As P 1 and P 2 Polymerizing groups in [the group] can be exemplified by, for example, acryloyloxy, methacryloyloxy, etc., which are composed of CH2=CR 31 -C(=O)-O- groups; vinyl; vinyl ether; p-stilbene; acryloyl; methacryloyl; carboxyl; methyl carbonyl; hydroxyl; amide; alkylamino with 1 to 4 carbon atoms; amino; epoxy; oxetane; aldehyde; isocyanate; thioisocyanate, etc. R 31 This represents a hydrogen atom, a methyl group, or a chlorine atom. Preferably, it is CH2=CR. 31 The group represented by -C(=O)-O- is more preferably CH2=CH-C(=O)-O- (acryloyloxy) or CH2=C(CH3)-C(=O)-O- (methacryloyloxy), and is particularly preferred to be acryloyloxy.

[0173] In equation (I), p and q each independently represent 0 or 1.

[0174] The liquid crystal compound represented by formula (I) can be manufactured, for example, by the reaction of a hydrazine compound and a carbonyl compound as described in Japanese International Publication No. 2012 / 147904.

[0175] As a liquid crystal compound represented by formula (I), specific examples include compounds represented by the following formula.

[0176] [Chemical Formula 2]

[0177]

[0178] The liquid crystal composition may be further incorporated with any components as needed to combine with the liquid crystal compound. Any component may be used alone or in combination of two or more in any ratio.

[0179] For example, to promote the polymerization of liquid crystal compounds, the liquid crystal composition may contain a polymerization initiator as an arbitrary component. Either a thermal polymerization initiator or a photopolymerization initiator can be used as the polymerization initiator.

[0180] The liquid crystal composition may contain a surfactant as an arbitrary component. In particular, from the viewpoint of stably obtaining a liquid crystal cured layer with excellent orientation, a surfactant containing fluorine atoms in its molecule is preferred.

[0181] Furthermore, the liquid crystal composition may also contain antioxidants as an optional component. By using antioxidants, gelation of the liquid crystal composition can be inhibited, thus extending its shelf life. Antioxidants can be used alone or in combination in any ratio.

[0182] The liquid crystal composition may also contain a solvent as an arbitrary component. Preferably, the solvent is capable of dissolving the antidispersive liquid crystal compound. Organic solvents are typically used as such solvents.

[0183] Other components that may be included in the liquid crystal composition include, for example, metals; metal complexes; metal oxides such as titanium dioxide; colorants such as dyes and pigments; luminescent materials such as fluorescent materials and phosphorescent materials; leveling agents; thixotropic agents; gelling agents; polysaccharides; ultraviolet absorbers; infrared absorbers; antioxidants; and ion exchange resins. The amounts of these components relative to 100 parts by weight of the total liquid crystal compound can range from 0.1 parts by weight to 20 parts by weight, respectively.

[0184] The curing of a liquid crystal composition is typically achieved by polymerizing the polymeric compound contained in the liquid crystal composition. Thus, the liquid crystal alignment layer typically contains some or all of the polymer of the components contained in the liquid crystal composition. Therefore, when the liquid crystal compound is polymerizable, the liquid crystal alignment layer is a layer containing the polymer of the liquid crystal compound. Normally, polymerizing a liquid crystal compound results in the loss of liquid crystal properties, but in this application, the liquid crystal compound that has been polymerized in this way is also included in the term "liquid crystal compound contained in the liquid crystal alignment layer".

[0185] In a liquid crystal alignment layer, the fluidity of the liquid crystal composition is lost. Therefore, the alignment state of the liquid crystal compounds can typically be fixed in a liquid crystal alignment layer. In the term "liquid crystal compound with fixed alignment state," a polymer comprising the aforementioned liquid crystal compound is included. A liquid crystal alignment layer may comprise a combination of molecules of liquid crystal compounds with unfixed alignment states and molecules of liquid crystal compounds with fixed alignment states, but preferably, the alignment state of all molecules of the liquid crystal compounds contained in the liquid crystal alignment layer is fixed.

[0186] There is no particular limitation on the method for forming the liquid crystal alignment layer. For example, it can be formed by performing the following steps: forming a layer of liquid crystal composition containing liquid crystal compound on a film as a substrate, aligning the liquid crystal compound contained in the layer of liquid crystal composition, and curing the layer of liquid crystal composition.

[0187] [1-4. Preferred materials for the second optical anisotropy layer]

[0188] [1-4-1. Resin with negative intrinsic birefringence]

[0189] The second optical anisotropic layer can be a stretched film of the second resin film. The second resin film preferably comprises a resin having a negative intrinsic birefringence value. By using a resin having a negative intrinsic birefringence value as the material, the second optical anisotropic layer satisfying formula (2) can be easily manufactured by stretching the second resin film formed from that resin. Thus, the second optical anisotropic layer can be a layer formed by stretching a film (the second resin film) made from a resin having a negative intrinsic birefringence value. The second resin film is the resin film before stretching to form the second optical anisotropic layer.

[0190] Resins with negative intrinsic birefringence include polymers with negative intrinsic birefringence.

[0191] From the viewpoint of high manifestation of phase difference, polystyrene-based polymers are preferred as polymers with negative intrinsic birefringence. Furthermore, from the viewpoint of high heat resistance, copolymers of styrene or styrene derivatives with maleic anhydride are particularly preferred. In this case, the amount of maleic anhydride unit relative to 100 parts by weight of the polystyrene-based polymer 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 or less, more preferably 28 parts by weight or less, and particularly preferably 26 parts by weight or less. The aforementioned maleic anhydride unit refers to a structural unit having a structure formed by polymerizing maleic anhydride.

[0192] The proportion of polymer in the resin having a negative intrinsic birefringence is preferably 50% to 100% by weight, more preferably 70% to 100% by weight, and particularly preferably 90% to 100% by weight. By keeping the proportion of polymer within the above range, the second optical anisotropy layer can exhibit suitable optical properties.

[0193] The glass transition temperature of a resin with negative intrinsic birefringence is preferably 80°C or higher, more preferably 90°C or higher, even more preferably 100°C or higher, particularly preferably 110°C or higher, and especially preferably 120°C or higher. By setting the glass transition temperature of the resin with negative intrinsic birefringence to such a high level, the orientation relaxation of the resin with negative intrinsic birefringence can be reduced. Furthermore, there is no particular upper limit to the glass transition temperature of the resin with negative intrinsic birefringence, and it is typically below 200°C. The glass transition temperature can be measured using a differential scanning calorimeter based on JIS K 6911 at a heating rate of 10°C / min.

[0194] Resins with negative intrinsic birefringence values ​​tend to have low mechanical strength. For example, resins containing polystyrene-based polymers tend to have low mechanical strength. Therefore, the second optical anisotropy layer comprising a layer formed of a resin with negative intrinsic birefringence values ​​preferably has a protective layer in combination with the layer comprising the resin with negative intrinsic birefringence values, the protective layer being able to protect the layer comprising the resin with negative intrinsic birefringence values.

[0195] There are no particular limitations on the protective layer; for example, a layer formed of resin having a positive intrinsic birefringence value can be used. In this case, from the viewpoint of easily adjusting the phase difference in the second optical anisotropy layer, it is preferable that the in-plane phase difference and the phase difference in the thickness direction of the protective layer are close to zero. As a method to make the in-plane phase difference and the phase difference in the thickness direction of the protective layer close to zero, one example is to make the glass transition temperature of the resin contained in the protective layer lower than the glass transition temperature of the resin having a negative intrinsic birefringence value.

[0196] The protective layer can be applied to only one side of the layer formed by the resin with negative intrinsic birefringence, or it can be applied to both sides.

[0197] [1-5. Optical Anisotropic Laminates]

[0198] In the optical anisotropic laminate of this embodiment, either the first optical anisotropic layer or the second optical anisotropic layer is composed of a λ / 2 waveplate, and the other is composed of a λ / 4 waveplate. A λ / 2 waveplate is an optical component having an in-plane phase difference typically between 200 nm and 300 nm at a measurement wavelength of 590 nm. A λ / 4 waveplate is an optical component having an in-plane phase difference typically between 75 nm and 154 nm at a measurement wavelength of 590 nm. By combining λ / 2 and λ / 4 waveplates, a broadband λ / 4 waveplate can be realized.

[0199] Therefore, the circular polarizer of this embodiment can exhibit the function of absorbing one of the right-hand circularly polarized light and the left-hand circularly polarized light, while transmitting the remaining light over a wide wavelength range. Thus, by using a circular polarizer having an optically anisotropic laminate in this manner, reflection of light over a wide wavelength range can be reduced in both the frontal and tilt directions.

[0200] [1-6. Manufacturing method of optical anisotropic laminates]

[0201] The optical anisotropic laminate of this embodiment can be manufactured by a manufacturing method including the following steps: Step 1, stretching a first resin film containing a resin having a positive intrinsic birefringence value to obtain a first optical anisotropic layer; Step 2, stretching a second resin film containing a resin having a negative intrinsic birefringence value to obtain a second optical anisotropic layer; Step 3, overlapping the first optical anisotropic layer and the second optical anisotropic layer.

[0202] [1-6-1. Process 1]

[0203] Step 1 is a step of stretching a first resin film containing a resin having a positive intrinsic birefringence value to obtain a first optical anisotropy layer.

[0204] The first resin film used in step 1, comprising a resin having a positive intrinsic birefringence value, can be manufactured by melt molding or solution casting, with melt molding being preferred. Furthermore, in melt molding, extrusion molding, blow molding, or compression molding are preferred, with extrusion molding being particularly preferred.

[0205] The first resin film is typically obtained in the form of a strip of resin film. By preparing the first resin film in the form of a strip of resin film, some or all of the processes can be carried out in an assembly line during the manufacture of the first optical anisotropic layer, thus enabling simple and efficient manufacturing.

[0206] The stretching method for the first resin film can be any suitable method depending on the optical properties desired to be revealed through stretching. In this embodiment, the stretching method for the first resin film is not particularly limited, but unidirectional stretching (uniaxial stretching) is preferred. By unidirectionally stretching the first resin film, the uniaxiality of the layer containing the resin having a positive intrinsic birefringence value can be improved, and NZ1 can be made 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 also be stretched once in one or both directions.

[0207] The stretching direction of the first resin film is not particularly limited. The stretching of the first resin film may include stretching in an oblique direction. By a manufacturing method that includes stretching in an oblique direction, a first optical anisotropic layer as an obliquely stretched film can be obtained. An obliquely stretched film means a film manufactured by a manufacturing method that includes stretching in an oblique direction. Typically, a slow axis that is neither parallel nor perpendicular to its width direction appears in an obliquely stretched film. Therefore, in the first optical anisotropic layer of this obliquely stretched film, a slow axis at a predetermined angle to the width direction can be easily formed. Therefore, the first optical anisotropic layer as an obliquely stretched film can be easily manufactured into a circular polarizer by rolling it with a polarizing film and a second optical anisotropic layer that have a transmission axis in the width direction.

[0208] The stretching 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, and preferably 4 times or less, more preferably 3 times or less, and particularly preferably 2.5 times or less. When stretching in two or more directions, it is desirable that the product of the stretching ratios in each direction is within the above-mentioned range. By keeping the stretching ratio within the above-mentioned range, it is easy to obtain a first optical anisotropic layer with desired optical properties.

[0209] The stretching temperature of the first resin film is preferably Tg1°C or higher, more preferably Tg1+2°C or higher, particularly preferably Tg1+5°C or higher, and more preferably Tg1+40°C or lower, more preferably Tg1+35°C or lower, and particularly preferably Tg1+30°C or lower. Here, Tg1 represents the glass transition temperature of the resin having a positive intrinsic birefringence value. By keeping the stretching temperature within the above-mentioned range, the molecules contained in the first resin film can be reliably oriented, thus making it easy to obtain a first optical anisotropy layer with desired optical properties.

[0210] In step 1 (method for manufacturing the first optical anisotropy layer), any further steps other than those described above may be performed. For example, when manufacturing a strip of the first optical anisotropy layer using a strip of first resin film, a cutting step can be performed to cut the first optical anisotropy layer into a desired shape. By performing the cutting step, a single sheet of the first optical anisotropy layer with the desired shape can be obtained. Furthermore, a step such as providing a protective layer to the first optical anisotropy layer may also be performed.

[0211] [1-6-2. Process 2]

[0212] Step 2 is a step of stretching a second resin film containing a resin with a negative intrinsic birefringence value to obtain a second optical anisotropy layer.

[0213] The second resin film used in step 2, comprising a resin having a negative intrinsic birefringence value, can be manufactured by melt molding or solution casting, with melt molding being preferred. Furthermore, in melt molding, extrusion molding, blow molding, or compression molding are preferred, with extrusion molding being particularly preferred.

[0214] When the second resin film is, for example, a multilayer film having a layer formed of a resin with a negative intrinsic birefringence value and a protective layer, co-extrusion molding methods such as co-extrusion T-die method, co-extrusion blow molding method, and co-extrusion lamination method can be used; film lamination molding methods such as dry lamination; and coating molding methods such as coating a resin solution constituting layers other than a certain layer with a certain layer. Among these, co-extrusion molding methods are preferred from the viewpoint of good manufacturing efficiency and preventing volatile components such as solvents from remaining in the second optical anisotropy layer. Among co-extrusion molding methods, co-extrusion T-die method is preferred. Furthermore, in co-extrusion T-die method, feed pipe method and manifold method can be cited, and from the viewpoint of reducing layer thickness deviation, manifold method is further preferred.

[0215] The second resin film is typically obtained in the form of a strip of resin film. By preparing the second resin film in the form of a strip of resin film, some or all of the processes can be carried out in an assembly line during the manufacture of the second optical anisotropic layer, thus enabling simple and efficient manufacturing.

[0216] The stretching method for the second resin film can be any suitable method depending on the optical properties desired to be revealed through stretching. In this embodiment, the stretching method for the second resin film is not particularly limited, but biaxial stretching is preferred. By performing biaxial stretching on the second resin film, the biaxiality of the layer containing the resin having a negative intrinsic birefringence value can be improved, and the NZ2 value can be made smaller than 0. Biaxial stretching includes, for example, successive biaxial stretching and simultaneous biaxial stretching.

[0217] The stretching direction of the second resin film is not particularly limited. The stretching of the second resin film preferably includes stretching in an oblique direction. By employing a manufacturing method that includes stretching in an oblique direction, a second optical anisotropic layer, serving as an obliquely stretched film, can be obtained. Typically, a slow axis that is neither parallel nor perpendicular to its width direction is observed in an obliquely stretched film. Therefore, in this second optical anisotropic layer, which is the obliquely stretched film, a slow axis at a predetermined angle to the width direction can be easily observed. Therefore, the second optical anisotropic layer, serving as the obliquely stretched film, can be easily manufactured into a circular polarizer by roller-to-roll bonding it to a polarizing film having a transmission axis in the width direction and a first optical anisotropic layer.

[0218] The stretching 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, and preferably 4 times or less, more preferably 3 times or less, and particularly preferably 2.5 times or less. When stretching in two or more directions, it is desirable that the product of the stretching ratios in each direction is within the above-mentioned range. By keeping the stretching ratio within the above-mentioned range, it is easy to obtain a second optical anisotropic layer with desired optical properties.

[0219] The stretching temperature of the second resin film is preferably Tg2°C or higher, more preferably Tg2+2°C or higher, particularly preferably Tg2+5°C or higher, and preferably Tg2+40°C or lower, more preferably Tg2+35°C or lower, and particularly preferably Tg2+30°C or lower. Here, Tg2 represents the glass transition temperature of the resin having a negative intrinsic birefringence. By keeping the stretching temperature within the above-mentioned range, the molecules contained in the second resin film can be reliably oriented, thus easily obtaining a second optical anisotropy layer with desired optical properties.

[0220] Step 2 can be performed simultaneously with Step 1, or it can be performed before Step 1. Furthermore, in Step 2 (the method for manufacturing the second optical anisotropy layer), any steps other than those described above can be performed. For example, any steps identical to those exemplified in Step 1 (the method for manufacturing the first optical anisotropy layer) can be performed.

[0221] [1-6-3. Process 3]

[0222] Step 3 is the process of overlapping the first optical anisotropic layer and the second optical anisotropic layer.

[0223] In step 3, the first optical anisotropic layer and the second optical anisotropic layer are overlapped such that the angle between the slow axis of the first optical anisotropic layer and the slow axis of the second optical anisotropic layer is 85° to 95°. That is, they are overlapped in such a way that the slow axis of the first optical anisotropic layer and the slow axis of the second optical anisotropic layer are orthogonal.

[0224] The angle between the slow axis of the first optical anisotropic layer and the slow axis of the second optical anisotropic layer is preferably 90°, and may include an error within the range of, for example, ±5°, ±3°, ±2°, or ±1°. Therefore, the angle between the slow axis of the first optical anisotropic layer and the slow axis of the second optical anisotropic layer may be, for example, 85°–95°, 87°–93°, 88°–92°, or 89°–91°. By using a circular polarizer having the obtained optical anisotropic laminate in a display device in this manner, the reflection of external light can be suppressed, and the reflection of external light when viewing the display surface from an inclined direction can be effectively suppressed, thus effectively suppressing color distortion.

[0225] [1-6-4. Bonding Process (Any Process)]

[0226] After overlapping the first optical anisotropic layer and the second optical anisotropic layer, an optical anisotropic laminate can be manufactured by bonding the two layers. A suitable adhesive can be used in the bonding process. For example, the same adhesive used in the manufacture of polarizers described below can be used as the adhesive. This bonding process is arbitrary.

[0227] [2. Circular Polarizer]

[0228] The circular polarizer 500 of this embodiment includes a linear polarizer 130 and the aforementioned optical anisotropic laminate 100. By providing the circular polarizer 500 of this embodiment on the display surface of the image display device, the reflection of external light can be suppressed. Based on the circular polarizer 500 of this embodiment having the optical anisotropic laminate 100 of this embodiment, when viewing the display surface from an inclined direction, the reflection of external light can be suppressed, and color distortion can be effectively suppressed.

[0229] like Figure 1 As shown, the circular polarizer 500 of this embodiment sequentially includes a linear polarizer 130, a first optical anisotropy layer 110, and a second optical anisotropy layer 120.

[0230] exist Figure 1 In the diagram, 132 is the axis onto which the transmission axis 131 of the linear polarizer 130 is projected onto the first optical anisotropic layer 110, and 133 is the axis onto which the transmission axis 131 of the linear polarizer 130 is projected onto the second optical anisotropic layer 120. Angle θA1 is the angle formed clockwise between the slow axis 111 of the first optical anisotropic layer 110 and the transmission axis 131 of the linear polarizer 130. Angle θB1 is the angle formed clockwise between the slow axis 121 of the second optical anisotropic layer 120 and the transmission axis 131 of the linear polarizer 130.

[0231] In the circular polarizer 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 optical anisotropy layer 110 is preferably close to 45°. Specifically, the angle θA1 is preferably 45°±5° (i.e., preferably 40° to 50°), more preferably 45°±4° (i.e., more preferably 41° to 49°), and particularly preferably 45°±3° (i.e., particularly preferably 42° to 48°).

[0232] Furthermore, although an example of the angle θA1 formed clockwise between the slow axis 111 of the first optical anisotropy layer 110 and the transmission axis 131 of the linear polarizer 130 is shown here, the orientation of the angle θA1 between the slow axis 111 of the first optical anisotropy layer 110 and the transmission axis 131 of the linear polarizer 130 can be either clockwise or counterclockwise. Similarly, the orientation of the angle θB1 between the slow axis 121 of the second optical anisotropy layer 120 and the transmission axis 131 of the linear polarizer 130 can also be either clockwise or counterclockwise.

[0233] Furthermore, in the circular polarizer 500, the angle between the absorption axis (not shown) of the linear polarizer 130 and the slow axis 111 of the first optical anisotropy layer 110 is preferably close to 45°. Specifically, the angle between the absorption axis of the linear polarizer 130 and the slow axis 111 of the first optical anisotropy layer 110 is preferably 45°±5° (i.e., preferably 40° to 50°), more preferably 45°±4° (i.e., more preferably 41° to 49°), and particularly preferably 45°±3° (i.e., particularly preferably 42° to 48°). The orientation of the aforementioned angle between the slow axis 111 of the first optical anisotropy layer 110 and the absorption axis of the linear polarizer 130 can be clockwise or counterclockwise.

[0234] As the linear polarizer 130, any linear polarizer can be used. Examples of linear polarizers include films obtained by unidirectionally stretching a polyvinyl alcohol film after adsorbing iodine or a dichroic dye into the film in a boric acid bath; and films obtained by adsorbing iodine or a dichroic dye into a polyvinyl alcohol film, stretching it, and then modifying a portion of the polyvinyl alcohol units in the molecular chain into polyethylene units. Other examples of linear polarizers include grid polarizers, multilayer polarizers, and other polarizers that have the function of separating polarized light into reflected and transmitted light. Among these, a polarizer containing polyvinyl alcohol is preferred as the linear polarizer 130.

[0235] When natural light is incident on the linear polarizer 130, only a portion of the polarized light is transmitted. The polarization degree of the linear polarizer 130 is not particularly limited, but is preferably 98% or more, and more preferably 99% or more.

[0236] Furthermore, the thickness of the linear polarizer 130 is preferably 5 μm to 80 μm.

[0237] The circular polarizer may further include an adhesive layer for bonding the linear polarizer to the optical anisotropic laminate. As the adhesive layer, an adhesive layer formed by an adhesive agent can be used, or a layer formed by curing a curable adhesive can be used. As the curable adhesive, a thermosetting adhesive can be used, preferably a photocurable adhesive. As the photocurable adhesive, a photocurable adhesive containing a polymer or reactive monomer can be used. Furthermore, the adhesive may, as needed, contain solvents, photopolymerization initiators, other additives, etc.

[0238] Photocurable adhesives are adhesives that can cure when exposed to light such as visible light, ultraviolet light, and infrared light. Among these, adhesives that can be cured by ultraviolet light are preferred due to their ease of use.

[0239] The thickness of the adhesive layer is preferably 0.5 μm or more, more preferably 1 μm or more, and more preferably 30 μm or less, more preferably 20 μm or less, and even more preferably 10 μm or less. By keeping the thickness of the adhesive layer within the above range, good adhesion can be achieved without sacrificing the optical properties of the optical anisotropic layer.

[0240] The circular polarizer described above can also contain arbitrary layers. Examples of arbitrary layers include, for instance, a polarizer protective film layer, an impact-resistant polymethyl methacrylate resin layer, or other hard coatings; a mat layer to improve the smoothness of the film; an anti-reflective layer; an anti-fouling layer; and an antistatic layer. These arbitrary layers can be provided as a single layer or as two or more layers.

[0241] [3. Image display device]

[0242] The circular polarizer of this embodiment can be used in an image display device. The image display device of this embodiment includes the circular polarizer of this embodiment and an organic electroluminescent element (hereinafter, sometimes appropriately referred to as "organic EL element"). This image display device typically includes a linear polarizer, an optically anisotropic laminate, and an organic EL element in sequence.

[0243] Furthermore, the image display device may sequentially include a linear polarizer, a first optical anisotropic layer, a second optical anisotropic layer, and an organic EL element.

[0244] Organic EL devices sequentially comprise a transparent electrode layer, a light-emitting layer, and an electrode layer. By applying a voltage to the transparent electrode layer and the electrode layer, the light-emitting layer can emit light. Examples of materials constituting the organic light-emitting layer include poly(p-phenylene oxide), polyfluorene, and polyvinylcarbazole-based materials. Furthermore, the light-emitting layer can be a stack of layers with multiple emission colors, or a mixed layer in which different pigments are doped into a layer of a certain pigment. Moreover, organic EL devices can have functional layers such as a hole injection layer, a hole transport layer, an electron injection layer, an electron transport layer, an equipotential surface formation layer, and a charge generation layer.

[0245] The image display device described above can suppress the reflection of external light from the display surface. Specifically, only a portion of the linearly polarized light incident from outside the device passes through a linear polarizer, and then through an optical anisotropic laminate, thereby transforming it into circularly polarized light. The circularly polarized light is reflected by a reflective light structural element within the display device (such as a reflective electrode in an organic EL element), and then passes again through the optical anisotropic laminate, transforming into linearly polarized light with a vibration direction orthogonal to the vibration direction of the incident linearly polarized light, and no longer passes through the linear polarizer. Here, the vibration direction of the linearly polarized light refers to the vibration direction of the electric field of the linearly polarized light. Thus, the function of suppressing reflection is achieved.

[0246] Furthermore, in an image display device, since the optically anisotropic laminate possesses specific optical properties, it can perform the aforementioned function of suppressing reflection not only in the front direction of the display surface but also in the tilted direction. This suppresses coloration of the display surface caused by reflected light. Therefore, the image display device can effectively suppress the reflection of external light and suppress coloration in both the front and tilted directions of the display surface.

[0247] The degree of coloration described above can be evaluated by the color difference ΔE*ab between the chromaticity measured when the display surface is viewed from an oblique direction and the chromaticity of the non-reflective black display surface. The chromaticity can be determined by measuring the spectrum of light reflected from the display surface, multiplying this spectrum by the spectral sensitivity (isochromatic function) corresponding to the human eye, and calculating the tristimulus values ​​X, Y, and Z to arrive at the chromaticity (a*, b*, L*). Furthermore, the color difference ΔE*ab can be calculated using the following formula (X) based on the chromaticity (a0*, b0*, L0*) of the display surface when it is not illuminated by external light and the chromaticity (a1*, b1*, L1*) when it is illuminated by external light.

[0248] [Mathematical Expression 1]

[0249]

[0250] Furthermore, the coloration of the display surface caused by reflected light generally varies depending on the azimuth angle of the viewing direction. Therefore, when observing from an angle where the display surface is tilted, the measured chromaticity differs depending on the azimuth angle of the viewing direction, and thus the chromaticity of the color difference Δ will also vary. Therefore, when evaluating the degree of color difference when observing from an angle where the display surface is tilted, as described above, it is preferable to evaluate the coloration by averaging the color differences ΔE*ab obtained from observations at multiple azimuth angles. Specifically, at an azimuth angle φ (reference... Figure 3 The color difference ΔE*ab is measured every 5° along the azimuth direction, within a range of 0° to less than 360°. The degree of coloring is evaluated by the average value of the measured color differences ΔE*ab (average color difference). The smaller the average color difference, the less coloring is observed on the display surface when viewed from an angle of inclination.

[0251] [Implementation Method 2]

[0252] The following is for reference. Figure 2 A circular polarizer having the optical anisotropic laminate of Embodiment 2 of the present invention, and an image display device having the circular polarizer, will be described. Figure 2 This is an exploded perspective view schematically representing the circular polarizer 600 of Embodiment 2.

[0253] Except for the different configurations of the second optical anisotropic layer 120 and the first optical anisotropic layer 110 compared to Embodiment 1, the optical anisotropic laminate 200 of this embodiment is configured in the same way as in Embodiment 1. In the following description, structures identical to those in Embodiment 1 are labeled with the same reference numerals, and repeated descriptions are omitted.

[0254] like Figure 2 As shown, the circular polarizer 600 of this embodiment includes a linear polarizer 130 and an optical anisotropic laminate 200 of this embodiment. Figure 2 As shown, the circular polarizer 600 of this embodiment sequentially includes a linear polarizer 130, the aforementioned second optical anisotropy layer 120, and a first optical anisotropy layer 110.

[0255] exist Figure 2In the diagram, 132 is the axis onto which the transmission axis of the linear polarizer is projected onto the first optical anisotropy layer 110, and 133 is the axis onto which the transmission axis of the linear polarizer is projected onto the second optical anisotropy layer 120. Angle θA2 is the angle formed clockwise between the slow axis 111 of the first optical anisotropy layer 110 and the transmission axis 131 of the linear polarizer 130. Angle θB2 is the angle formed clockwise between the slow axis 121 of the second optical anisotropy layer 120 and the transmission axis 131 of the linear polarizer 130. Angles θA2 and θB2 are preferably within the same range as angles θA1 and θB1 described in Embodiment 1, respectively.

[0256] The circular polarizer of this embodiment can be used in an image display device. An image display device typically includes a linear polarizer, an optical anisotropic layer, and an organic EL element in sequence. Therefore, an image display device having the circular polarizer of this embodiment can include a linear polarizer, a second optical anisotropic layer, a first optical anisotropic layer, and an organic EL element in sequence.

[0257] In this embodiment, the optical anisotropic laminate 200 also has optical characteristics that satisfy the above-described equations (1) to (4), and the angle between the slow axis 111 of the first optical anisotropic layer 110 and the slow axis 121 of the second optical anisotropic layer 120 is 85° to 95°. Therefore, by combining such an optical anisotropic laminate 200 with a linear polarizer 130 to obtain a circular polarizer 600, and by placing the circular polarizer 600 in an image display device, it is possible to effectively suppress the reflection of external light and thus suppress color distortion when viewing the display surface of the image display device from an oblique direction.

[0258]

Example

[0259] The following describes embodiments and provides a detailed account of the invention. However, the invention is not limited to the embodiments shown below, and any modifications can be made without departing from the scope of the invention and its equivalents.

[0260] In the following descriptions, unless otherwise stated, "%" and "parts" refer to quantities based on weight. Furthermore, unless otherwise stated, the operations described below are performed under normal temperature and pressure conditions.

[0261] [Evaluation Method]

[0262] (Methods for determining phase difference and NZ coefficient)

[0263] The phase difference was measured at multiple locations spaced 50 mm apart along the width of the evaluation object (first optical anisotropic layer, second optical anisotropic layer, and optical anisotropic laminate) using a phase difference meter (AxoScan, manufactured by Axometrics). The average value of the measured values ​​at these locations was calculated and taken as the phase difference of the evaluation object.

[0264] For the first optical anisotropic layer, in-plane phase differences Re1(450), Re1(550), Re1(590), and Re1(650) were measured at wavelengths of 450 nm, 550 nm, 590 nm, and 650 nm. The thickness-direction phase difference Rth1(590) and the slow-axis phase difference were also measured at wavelength 590 nm. Furthermore, for the second optical anisotropic layer, in-plane phase differences Re2(450), Re2(550), Re2(590), and Re2(650) were measured at wavelengths of 450 nm, 550 nm, 590 nm, and 650 nm. The thickness-direction phase difference Rth2(590) and the slow-axis phase difference were also measured at wavelength 590 nm. Using the obtained in-plane phase differences, Re1(450) / Re1(550) and Re2(450) / Re2(550) were calculated. In addition, the NZ coefficients (NZ1, NZ2) are calculated based on the ratio of the in-plane phase difference to the phase difference in the thickness direction.

[0265] Furthermore, based on the optical characteristic values ​​of the first optical anisotropic layer and the second optical anisotropic layer, the in-plane phase differences Re(450), Re(550), and Re(650) of the optical anisotropic laminate at wavelengths of 450 nm, 550 nm, and 650 nm are calculated.

[0266] (A method for calculating color difference based on simulation)

[0267] Using SHINTEC Co., Ltd.'s "LCD Mastere" as simulation software, the circular polarizers manufactured in each embodiment and comparative example were modeled, and the following calculations were performed.

[0268] In the simulation model, a structure with a circular polarizer is provided on the reflective surface of a mirror having a planar reflective surface. This circular polarizer, starting from the reflective surface side, sequentially comprises a second optical anisotropy layer, a first optical anisotropy layer, and a polarizing film. The first and second optical anisotropy layers are the optical anisotropy layers used in the various embodiments and comparative examples. Furthermore, the polarizing film is a commonly used polarizer with a polarization degree of 99.99%. Additionally, the mirror is an ideal mirror capable of specular reflection of incident light with 100% reflectivity.

[0269] Figure 3 This is a perspective view schematically representing the state of the evaluation model set during the calculation of color space coordinates in the simulations of the embodiments and comparative examples.

[0270] like Figure 3 As shown, the color space coordinates observed on the reflecting surface 10 of a mirror with a circular polarizer when illuminated by a D65 light source (not shown) were calculated. Furthermore, the color space coordinates when not illuminated by the light source were set as a0*=0, b0*=0, L0*=0. Then, based on (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 was calculated using the above equation (X).

[0271] The color difference ΔE*ab described above is calculated in the observation direction 20 with a polar angle ρ of 0° relative to the reflecting surface 10, to obtain the color difference ΔE*ab in the front direction. The polar angle ρ represents the angle formed with the normal direction 11 of the reflecting surface 10.

[0272] Furthermore, the calculation of the aforementioned color difference ΔE*ab is performed in the observation direction 20 with a polar angle ρ of 60° relative to the reflecting surface 10. This polar angle ρ = 60° is calculated multiple times within a range where the azimuth angle φ is greater than or equal to 0° and less than 360°, by moving the observation direction 20 5° along the azimuth direction each time. The azimuth angle φ represents the angle formed by a direction parallel to the reflecting surface 10 relative to a reference direction 12 parallel to the reflecting surface 10. Then, the average value of the calculated color differences ΔE*ab in the observation direction 20 is calculated to obtain the color difference ΔE*ab in the tilted direction with a polar angle ρ = 60°.

[0273] (Evaluation method of circular polarizer based on visual inspection from the front view)

[0274] As an image display device with a mirror, Apple's "Apple Watch" (registered trademark) is prepared. The polarizer attached to the mirror of the image display device is peeled off to expose the mirror. The surface of the mirror and the surface of the second optical anisotropy layer of the circular polarizer of the evaluation object are bonded together via an adhesive layer (manufactured by Nitto Denko Corporation, "CS9621").

[0275] Observe the circular polarizer on a mirror under sunlight on a sunny day. The observation should be conducted from the front direction of the polarizer, where the polar angle and azimuth angle are both 0°. Based on the observation, if color is visually confirmed, classify it as "B"; otherwise, classify it as "A".

[0276] (Evaluation method of circular polarizer based on visual inspection in tilt direction)

[0277] As an image display device with a mirror, Apple's "Apple Watch" (registered trademark) is prepared. The polarizer attached to the mirror of the image display device is peeled off to expose the mirror. The surface of the mirror and the surface of the second optical anisotropy layer of the circular polarizer of the evaluation object are bonded together via an adhesive layer (manufactured by Nitto Denko Corporation, "CS9621").

[0278] The circular polarizer was observed visually on a mirror under sunlight on a sunny day. Observations were made along the polar angle of 60° and the azimuth angle from 0° to 360°. Based on the observations, the reflectivity and coloration were comprehensively evaluated, and the examples and comparative examples were ranked. Then, scores corresponding to their rankings were assigned to the ranked examples and comparative examples (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, 8th place: 1 point).

[0279] Multiple individuals conducted the above observations, and the total scores given for each embodiment and comparative example were calculated. The embodiments and comparative examples were arranged in order of the total scores, and the range of total scores was divided into five equal parts, evaluated sequentially from top to bottom as A, B, C, D, and E.

[0280] [Manufacturing Example]

[0281] [Manufacturing Example 1: Manufacturing of Polarizing Film (Linear Polarizer)]

[0282] A long strip of pre-stretching film made of polyvinyl alcohol resin stained with iodine is prepared. This pre-stretching film is stretched along its length at a 90° angle to its width direction to obtain a long strip of polarizing film. This polarizing film has an absorption axis along its length direction and a transmission axis along its width direction.

[0283] [Manufacturing Example 2-1: Manufacturing of λ / 2 Wave Plate A]

[0284] As the first resin film (pre-stretching film), a long strip of cyclic olefin resin film (manufactured by Zeon Corporation, "ZeonorFilm", glass transition temperature 126°C) is prepared to be obtained by molding a cyclic olefin polymer into a film shape via melt extrusion. The cyclic olefin resin forming this first resin film is a resin with a positive intrinsic birefringence value.

[0285] The cyclic olefin resin film was stretched in the width direction to obtain a long strip of λ / 2 waveplate. The stretching process in the width direction was set in the range of stretching temperature 120°C to 150°C and stretching ratio 2.0 to 5.0 times to obtain the λ / 2 waveplate with the physical property values ​​(Re1, Rth1) listed in the first optical anisotropy layer column of Example 1 in Table 1 below. In this way, a long strip of λ / 2 waveplate A was obtained. The film thickness of the λ / 2 waveplate A is 50 μm. The in-plane phase difference and the phase difference in the thickness direction of the λ / 2 waveplate A were measured according to the above method. 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. According to the result, the relationship between nx1, ny1 and nz1 is nx1 > ny1 > nz1, which satisfies equation (1).

[0286] [Manufacturing Example 2-2: Manufacturing of λ / 2 Wave Plate B]

[0287] As a pre-stretching film, a long strip of cyclic olefin resin film (manufactured by Zeon Corporation, "ZeonorFilm", glass transition temperature 126°C) is prepared by melt extrusion molding a cyclic olefin polymer into a film shape. The cyclic olefin resin forming this pre-stretching film is a resin with a positive intrinsic birefringence.

[0288] The cyclic olefin resin film was stretched in the width direction to obtain a long λ / 2 waveplate. The stretching process in the width direction was set in the range of stretching temperature 120°C to 150°C and stretching ratio 2.0 to 5.0 times to obtain a λ / 2 waveplate with the physical property values ​​(Re1, Rth1) listed in the first optical anisotropy layer column of Comparative Example 2 in Table 2 below. A long λ / 2 waveplate B was obtained in this way. The film thickness of the λ / 2 waveplate B is 50 μm. The in-plane phase difference and the phase difference in the thickness direction of the λ / 2 waveplate B were measured according to the above method. 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. The result shows that the relationship between nx1, ny1 and nz1 is nx1 > ny1 > nz1, which satisfies equation (1).

[0289] [Manufacturing Example 3-1: Manufacturing of λ / 4 waveplates A to E (second optical anisotropy layer of Examples 1 to 4 and Comparative Example 3)]

[0290] (3-1-1: Manufacturing of the second resin film (pre-stretching film))

[0291] As a resin with negative intrinsic birefringence, a styrene-maleic acid copolymer resin (manufactured by NovaChemical Corporate, “Daylark D332”, glass transition temperature 130°C, oligomer content 3% by weight) was prepared.

[0292] The acrylic resin to be used as the protective layer is "SUMIPEX HT-55X" (glass transition temperature 105°C) manufactured by Sumitomo Chemical Co., Ltd.

[0293] As an adhesive, a modified ethylene-vinyl acetate copolymer (MODICAP A543 manufactured by Mitsubishi Chemical Corporation, with a Vicat softening point of 80°C) is prepared.

[0294] The prepared styrene-maleic acid copolymer resin, acrylic resin and adhesive are co-extruded to obtain a second resin film that sequentially has an acrylic resin layer, an adhesive layer, a styrene-maleic acid copolymer resin layer, an adhesive layer and an acrylic resin layer.

[0295] (3-1-2: Fabrication of λ / 4 waveplate)

[0296] The second resin film manufactured in (3-1-1) was subjected to stretching treatment in both the width and length directions (bidirectional stretching treatment) to obtain a long strip of λ / 4 waveplate. The conditions for the bidirectional stretching treatment were set in a manner that yielded λ / 4 waveplates with the physical property values ​​(Re2, Rth2) listed in the second optical anisotropy layer column of Examples 1 to 4 and Comparative Example 3 in Table 1 below. Specifically, in order to obtain λ / 4 waveplates, the stretching treatment conditions in the width direction were set to a stretching temperature of 110°C to 140°C and a stretching ratio of 1.5 to 4.0, and the stretching treatment conditions in the length direction were set to a stretching temperature of 110°C to 140°C and a stretching ratio of 1.5 to 4.0. λ / 4 waveplates A to E were obtained in this manner. The film thickness of the obtained λ / 4 waveplates A to E was 40 μm.

[0297] The in-plane phase difference and the phase difference in the thickness direction of the obtained λ / 4 waveplates A to E were measured respectively according to the above method. No phase difference was observed in the acrylic resin layer and the adhesive layer of each λ / 4 waveplate.

[0298] The measurements of the λ / 4 waveplate A are as follows: Re2(590) = 147 nm, Rth2(590) = -132 nm, nx2 = 1.5582, ny2 = 1.5545, and nz2 = 1.5597.

[0299] The measurements of the λ / 4 waveplate B are as follows: Re2(590) = 147 nm, Rth2(590) = -162 nm, nx2 = 1.5580, ny2 = 1.5543, and nz2 = 1.5602.

[0300] The measurements of the λ / 4 waveplate C are as follows: Re2(590) = 147 nm, Rth2(590) = -191 nm, nx2 = 1.5577, ny2 = 1.5540, and nz2 = 1.5607.

[0301] The measurements of the λ / 4 waveplate D are as follows: Re2(590) = 147 nm, Rth2(590) = -220 nm, nx2 = 1.5575, ny2 = 1.5538, and nz2 = 1.5611.

[0302] The measurements of the λ / 4 waveplate E are as follows: Re2(590) = 147 nm, Rth2(590) = -162 nm, nx2 = 1.5580, ny2 = 1.5543, and nz2 = 1.5602.

[0303] The result shows that the relationship between nx2, ny2 and nz2 for any one of the λ / 4 waveplates A to E is nz2>nx2>ny2, which satisfies equation (2).

[0304] [Manufacturing Example 3-2: Manufacturing of λ / 4 Wave Plate F]

[0305] Using the pre-stretch membrane manufactured in (3-1-1) of Manufacturing Example 3-1, a λ / 4 waveplate F is manufactured according to the following method.

[0306] A pre-stretched film was subjected to a stretching process along its width to obtain a long strip of λ / 4 waveplate F. The stretching process along the width was set to a stretching temperature of 110°C to 140°C and a stretching ratio of 1.5 to 4.0 times to obtain a λ / 4 waveplate with the physical property values ​​(Re2, Rth2) listed in the second optical anisotropy layer column of Comparative Example 1 in Table 2 below. The long strip of λ / 4 waveplate F was obtained in this manner. The film thickness of λ / 4 waveplate F was 40 μm.

[0307] The in-plane phase difference and the phase difference along the thickness direction of the λ / 4 waveplate F were measured using the method described above. No phase difference was observed in the acrylic resin layer and the adhesive layer of the obtained λ / 4 waveplate. 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 these results, it can be seen that the relationship between nx2, ny2, and nz2 is nz2 > nx2 > ny2.

[0308] [Example 1]

[0309] Strips of polarizing film, strips of λ / 2 waveplate A, and strips of λ / 4 waveplate A are cut separately to obtain single sheets of polarizing film, single sheets of λ / 2 waveplate A, and single sheets of λ / 4 waveplate A. These single sheets of polarizing film, single sheets of λ / 2 waveplate A, and single sheets of λ / 4 waveplate A are bonded together using an adhesive (Nitto Denko Corporation "CS9621") to obtain a circular polarizer having, in sequence, a polarizing film, an adhesive layer, a λ / 2 waveplate A (first optical anisotropy layer), an adhesive layer, and a λ / 4 waveplate A (second optical anisotropy layer). This circular polarizer corresponds to the method of Embodiment 1 (see reference). Figure 1 In this circular polarizer, λ / 2 waveplate A is the first optical anisotropic layer, and λ / 4 waveplate A is the second optical anisotropic layer. The bonding is performed as follows: the angle θA1 formed clockwise between the slow axis of λ / 2 waveplate A and the transmission axis of the polarizer, when viewed from the polarizing film side, is 45°, and the angle θB1 formed clockwise between the slow axis of λ / 4 waveplate A and the transmission axis of the polarizing film is 135°. The obtained circular polarizer is evaluated according to the above method.

[0310] The Re(450), Re(550) and Re(650) of the optical anisotropic stack contained in the circular polarizer in this example satisfy the following equation (3).

[0311] Re(450)<Re(550)<Re(650) Formula (3)

[0312] Furthermore, in the optical anisotropic laminate, the first optical anisotropic layer satisfies the following equation (1), the second optical anisotropic layer satisfies the following equation (2), and the sum of NZ1 and NZ2 is 0.7.

[0313] nx1>ny1≥nz1 Equation (1)

[0314] Equation (2) is: nz² > nx² > ny²

[0315] [Example 2]

[0316] Except for changing the long λ / 4 waveplate A to a long λ / 4 waveplate B, the same operation as in Example 1 was performed to obtain a circular polarizer having a polarizing film, an adhesive layer, a λ / 2 waveplate A, an adhesive layer, and a λ / 4 waveplate B in sequence. In this circular polarizer, the λ / 2 waveplate A is the first optical anisotropic layer, and the λ / 4 waveplate B is the second optical anisotropic layer. The obtained circular polarizer was evaluated according to the above method. The Re(450), Re(550), and Re(650) of the optical anisotropic layer included in the circular polarizer satisfy the above equation (3). Furthermore, in the optical anisotropic layer, the first optical anisotropic layer satisfies the above equation (1), the second optical anisotropic layer satisfies the above equation (2), and the sum of NZ1 and NZ2 is 0.5.

[0317] [Example 3]

[0318] Except for changing the long λ / 4 waveplate A to a long λ / 4 waveplate C, the same operation as in Example 1 was performed to obtain a circular polarizer having a polarizing film, an adhesive layer, a λ / 2 waveplate A, an adhesive layer, and a λ / 4 waveplate C in sequence. In this circular polarizer, the λ / 2 waveplate A is the first optical anisotropic layer, and the λ / 4 waveplate C is the second optical anisotropic layer. The obtained circular polarizer was evaluated according to the above method. The Re(450), Re(550), and Re(650) of the optical anisotropic layer included in the circular polarizer satisfy the above equation (3). Furthermore, in the optical anisotropic layer, the first optical anisotropic layer satisfies the above equation (1), the second optical anisotropic layer satisfies the above equation (2), and the sum of NZ1 and NZ2 is 0.3.

[0319] [Example 4]

[0320] Except for changing the long λ / 4 waveplate A to a long λ / 4 waveplate D, the same operation as in Example 1 was performed to obtain a circular polarizer having a polarizing film, an adhesive layer, a λ / 2 waveplate A, an adhesive layer, and a λ / 4 waveplate D in sequence. In this circular polarizer, the λ / 2 waveplate A is the first optical anisotropic layer, and the λ / 4 waveplate D is the second optical anisotropic layer. The obtained circular polarizer was evaluated according to the above method. The Re(450), Re(550), and Re(650) of the optical anisotropic stack contained in the circular polarizer satisfy the above equation (3). Furthermore, in the optical anisotropic stack, the first optical anisotropic layer satisfies the above equation (1), the second optical anisotropic layer satisfies the above equation (2), and the sum of NZ1 and NZ2 is 0.1.

[0321] [Comparative Example 1]

[0322] Except for changing the long λ / 4 waveplate A to a long λ / 4 waveplate F, the same operation as in Example 1 was performed to obtain a circular polarizer having a polarizing film, an adhesive layer, a λ / 2 waveplate A, an adhesive layer, and a λ / 4 waveplate F in sequence. In this circular polarizer, the λ / 2 waveplate A is the first optical anisotropic layer, and the λ / 4 waveplate F is the second optical anisotropic layer. The obtained circular polarizer was evaluated according to the above method. The Re(450), Re(550), and Re(650) of the optical anisotropic stack contained in the circular polarizer are Re(450) < Re(550) < Re(650), satisfying the above equation (3). In the optical anisotropic stack, the first optical anisotropic layer satisfies the above equation (1), the second optical anisotropic layer satisfies the above equation (2), and the sum of NZ1 and NZ2 is 1.0.

[0323] [Comparative Example 2]

[0324] Except for the following changes, the same operation as in Example 1 was performed to obtain a circular polarizer having a polarizing film, an adhesive layer, a λ / 2 waveplate B, an adhesive layer, and a λ / 4 waveplate F in sequence. In this circular polarizer, the λ / 2 waveplate B is the first optical anisotropic layer, and the λ / 4 waveplate F is the second optical anisotropic layer. The obtained circular polarizer was evaluated according to the above method. Furthermore, the Re(450), Re(550), and Re(650) of the optical anisotropic stack included in the circular polarizer are Re(450) < Re(550) < Re(650), satisfying the above equation (3). In the optical anisotropic stack, the first optical anisotropic layer satisfies the above equation (1), the second optical anisotropic layer satisfies the above equation (2), and the sum of NZ1 and NZ2 is 1.08.

[0325] (Change Point)

[0326] • Change the long λ / 2 waveplate A to a long λ / 2 waveplate B.

[0327] • Change the long λ / 4 waveplate A to a long λ / 4 waveplate F.

[0328] The bonding of the layers is performed as follows: when viewed from the polarizing film side, the angle θA1 formed clockwise between the slow axis of the λ / 2 waveplate B and the transmission axis of the polarizing film is 22.5°, and the angle θB1 formed clockwise between the slow axis of the λ / 4 waveplate F and the transmission axis of the polarizing film is 90°.

[0329] [Comparative Example 3]

[0330] Except for the following changes, the same operation as in Example 1 was performed to obtain a circular polarizer having a polarizing film, an adhesive layer, a λ / 2 waveplate B, an adhesive layer, and a λ / 4 waveplate E in sequence. In this circular polarizer, the λ / 2 waveplate B is the first optical anisotropic layer, and the λ / 4 waveplate E is the second optical anisotropic layer. The obtained circular polarizer was evaluated according to the above method. Furthermore, the Re(450), Re(550), and Re(650) of the optical anisotropic stack included in the circular polarizer are Re(450) < Re(550) < Re(650), satisfying the above equation (3). Furthermore, in the optical anisotropic stack, the first optical anisotropic layer satisfies the above equation (1), the second optical anisotropic layer satisfies the above equation (2), and the sum of NZ1 and NZ2 is 0.58.

[0331] (Change Point)

[0332] • Change the long λ / 2 waveplate A to a long λ / 2 waveplate B.

[0333] • Change the long λ / 4 waveplate A to the long λ / 4 waveplate E.

[0334] The bonding of the layers is carried out in the following manner: when viewed from the polarizing film side, the angle θA1 formed clockwise between the slow axis of the λ / 2 waveplate B and the transmission axis of the polarizing film is 22.5°, and the angle θB1 formed clockwise between the slow axis of the λ / 4 waveplate E and the transmission axis of the polarizing film is 90°.

[0335] [Comparative Example 4]

[0336] The circular polarizer of Comparative Example 4 was manufactured according to the following method (the same method as in Example 1 of Japanese Patent Application Publication No. 2010-266723).

[0337] Manufacturing of (C4-1) Film C1 (a film containing a resin with an inherently positive birefringence)

[0338] A roll-wound body of a first unstretched film formed from a norbornene polymer (Zeon Corporation, "ZEONOR 1420", glass transition temperature: 136°C) is obtained by melt extrusion molding. Next, a widening stretching machine (refer to Japanese Patent Application Publication No. 2010-266723) is used. Figure 2 The first unstretched film was obliquely stretched at a 45° angle to the width direction under the conditions of a stretching temperature of 147°, a stretching ratio of 1.7, and a stretching speed of 13 mm / min, thereby obtaining the film C1. The obtained film C1 has an Nz coefficient (NZ1) of 1.1, a Re1 (590) of 66 nm, an angle of 44.8° between the slow axis and the width direction, and a thickness of 120 μm.

[0339] Manufacturing of (C4-2) Film C2 (film containing resin with inherently negative birefringence)

[0340] A roll-wound unstretched laminate (roll-wound of the second unstretched film) is obtained by co-extrusion molding. This roll-wound unstretched laminate has an a-layer formed of polymethyl methacrylate resin containing elastomer particles with a number-average particle size of 0.4 μm, and a b-layer formed of a styrene-maleic acid copolymer (manufactured by Nova Chemical Corporate, trade name "Daylark D332", glass transition temperature: 130°C, oligomer content: 3% by weight) in the order of a-layer (30 μm)-b-layer (30 μm). Next, the unstretched laminate is pulled from this roll-wound and stretched obliquely at a 45° angle to the width direction using the same stretching machine as (C4-1) at a stretching temperature of 138°C, a stretch ratio of 1.7, and a stretching speed of 8 mm / min, thereby obtaining the roll-wound film C2. The obtained film C2 has an Nz coefficient (NZ2) of -0.1, a Re2 (590) of 66 nm, an angle of -45.2° between the slow axis and the width direction, and a thickness of 130 μm.

[0341] (C4-3) Fabrication of Optical Anisotropic Laminates

[0342] The membrane C1 obtained in (C4-1) and the membrane C2 obtained in (C4-2) are pulled out separately using a lamination apparatus (refer to Japanese Patent Application Publication No. 2010-266723). Figure 3 The optically anisotropic laminate C3 is obtained by stacking the rollers together in a way that the in-plane slow axes are parallel to each other.

[0343] (C4-4) Manufacturing of Circular Polarizers

[0344] Using a lamination apparatus (refer to Figure 4 of Japanese Patent Application Publication No. 2010-266723), the optically anisotropic laminate C3 obtained in (C4-3) and the polarizing film (SANRITZ CO.,LTD. HLC2-5618S, 180 μm thick) are laminated by a roll-to-roll method to manufacture a circular polarizing film. The film is then cut to a specified size to obtain a circular polarizer.

[0345] The circular polarizer obtained was evaluated using the same evaluation method as in the embodiment described above. In this example, the relationship between Re(450), Re(550), and Re(650) of the optical anisotropic stack comprising the circular polarizer is Re(450) > Re(550) > Re(650), which does not satisfy equation (3) above. Furthermore, in the optical anisotropic stack, the first optical anisotropic layer satisfies equation (1), the second optical anisotropic layer satisfies equation (2), and the sum of NZ1 and NZ2 is 1.0.

[0346] [result]

[0347] Tables 1 and 2 below show the results of the embodiments and comparative examples. In Tables 1 and 2, the abbreviations have the following meanings.

[0348] COP: Cycloolefin resin

[0349] PSt: Styrene-maleic acid copolymer resin

[0350] Re1(590): Measure the in-plane phase difference of the λ / 2 waveplate (first optical anisotropic layer) at a wavelength of 590 nm.

[0351] Re1(550): Measure the in-plane phase difference of the λ / 2 waveplate (first optical anisotropic layer) at a wavelength of 550 nm.

[0352] Re1(450): Measure the in-plane phase difference of the λ / 2 waveplate (first optical anisotropic layer) at a wavelength of 450 nm.

[0353] Rth1(590): Measure the phase difference in the thickness direction of the λ / 2 waveplate (first optical anisotropic layer) at a wavelength of 590 nm.

[0354] θA1: The angle between the slow axis of the λ / 2 waveplate (first optical anisotropy layer) and the transmission axis of the polarization film, viewed from the polarization film side, in a clockwise direction.

[0355] NZ1: NZ coefficient of the λ / 2 waveplate (first optical anisotropic layer).

[0356] Re2(590): Measure the in-plane phase difference of the λ / 4 waveplate (second optical anisotropic layer) at a wavelength of 590 nm.

[0357] Re2(550): Measure the in-plane phase difference of the λ / 4 waveplate (second optical anisotropic layer) at a wavelength of 550 nm.

[0358] Re2(450): Measure the in-plane phase difference of the λ / 4 waveplate (second optical anisotropy layer) at a wavelength of 450 nm.

[0359] Rth2(590): The phase difference in the thickness direction of the λ / 4 waveplate (second optical anisotropic layer) at a wavelength of 590 nm is measured.

[0360] θB1: The angle between the slow axis of the λ / 4 waveplate (second optical anisotropy layer) and the transmission axis of the polarization film, viewed from the polarization film side, in a clockwise direction.

[0361] NZ2: NZ coefficient of λ / 4 waveplate (second optical anisotropy layer).

[0362] Angle formed by the slow axis: The angle formed by the slow axis of the first optical anisotropy layer and the slow axis of the second optical anisotropy layer.

[0363] ΔE*ab (front view): Color difference when observed from the polar angle ρ=0°.

[0364] Visual observation (front view): Color difference when observed from a polar angle ρ = 0°.

[0365] ΔE*ab (oblique direction): The average color difference when observed from a polar angle ρ = 60°.

[0366] Visual observation (oblique direction): Color difference when observed visually from a polar angle ρ = 60°.

[0367] *1: As shown in this example, when the slow axis of the first optical anisotropy layer and the slow axis of the second optical anisotropy layer are not orthogonal, although the difference between Re1 and Re2 may sometimes differ depending on the measuring device, the difference between Re1 (550) and Re2 (550) measured by a phase difference meter ("AxoScan" manufactured by Axometrics Corporation) is recorded in the same way as in other examples.

[0368] [Table 1]

[0369]

[0370] [Table 2]

[0371]

[0372] Based on the above results, it can be seen that, compared with the image display device having the optical anisotropic laminate of Examples 1-4, the image display device having the optical anisotropic laminate of Examples 1-4 can suppress the coloration of the display surface when viewed from the front direction, and can also suppress the coloration of the display surface when viewed from the oblique direction. From the above results, it can be seen that, according to Examples 1-4 having the optical anisotropic laminate of the present invention, an image display device that suppresses the coloration of the display surface when viewed from the front direction and the oblique direction can be realized.

[0373] [Other Implementation Methods]

[0374] (1) In the above embodiments 1 to 4, although an optical anisotropic laminate with a λ / 2 waveplate used in the first optical anisotropic layer and a λ / 4 waveplate used in the second optical anisotropic layer was shown, the present invention is not limited thereto. An optical anisotropic laminate with a λ / 2 waveplate used in the second optical anisotropic layer and a λ / 4 waveplate used in the first optical anisotropic layer may also be used.

[0375] (2) In the above embodiments 1 to 4, although an optical anisotropic laminate with an angle θA1 of 45° formed clockwise between the slow axis of the λ / 2 waveplate (first optical anisotropic layer) and the transmission axis of the linear polarizer (polarization mode) is shown, the present invention is not limited thereto. It may also be an optical anisotropic laminate with an angle of 45° between the absorption axis of the linear polarizer and the slow axis of the first optical anisotropic layer.

[0376] Explanation of reference numerals in the attached figures

[0377] 100, 200: Optically anisotropic laminates

[0378] 110: First optical anisotropy layer

[0379] 111: Slow axis

[0380] 120: Second optical anisotropy layer

[0381] 121: Slow axis

[0382] 130: Linear polarizer

[0383] 131: Transmission axis

[0384] 500, 600: Optically anisotropic laminates

Claims

1. An optically anisotropic laminate, comprising a first optically anisotropic layer and a second optically anisotropic layer, The first optical anisotropic layer satisfies the following equation (1), The second optical anisotropic layer satisfies the following equation (2), The optically anisotropic laminate satisfies the following equation (3). The NZ coefficients NZ1 of the first optical anisotropic layer and NZ2 of the second optical anisotropic layer satisfy the following equation (4). The angle between the slow axis of the first optical anisotropy layer and the slow axis of the second optical anisotropy layer is 85° to 95°. nx1>ny1≥nz1 Equation (1) Equation (2) is: nz² > nx² > ny² Re(450)<Re(550)<Re(650) Formula (3) -0.3≤NZ1+NZ2≤0.8 Equation (4) in, nx1 represents the refractive index in the direction providing the maximum refractive index in the in-plane direction of the first optical anisotropic layer, ny1 represents the refractive index in the direction orthogonal to the direction providing nx1 in the in-plane direction of the first optical anisotropic layer, and nz1 represents the refractive index in the thickness direction of the first optical anisotropic layer. nx2 represents the refractive index in the direction providing the maximum refractive index in the in-plane direction of the second optical anisotropic layer, ny2 represents the refractive index in the in-plane direction of the second optical anisotropic layer that is orthogonal to the direction providing nx2, and nz2 represents the refractive index in the thickness direction of the second optical anisotropic layer. Re(450), Re(550), and Re(650) represent the in-plane phase differences of the optical anisotropic laminate at wavelengths of 450 nm, 550 nm, and 650 nm, respectively.

2. The optically anisotropic laminate according to claim 1, wherein, The in-plane phase difference Re1(550) of the first optical anisotropic layer at a wavelength of 550 nm The in-plane phase difference Re1(450) of the first optical anisotropic layer at a wavelength of 450 nm The in-plane phase difference Re2(550) of the second optical anisotropic layer at a wavelength of 550 nm The in-plane phase difference Re2(450) of the second optical anisotropic layer at a wavelength of 450 nm satisfies the following equations (5) and (6). Re1(450) / Re1(550)<Re2(450) / Re2(550) Equation (5) Re1(550)>Re2(550) Equation (6).

3. The optically anisotropic laminate according to claim 2, wherein, The difference between Re1(550) and Re2(550) is greater than 100nm and less than 180nm.

4. The optically anisotropic laminate according to any one of claims 1 to 3, wherein, The first optical anisotropic layer is a stretched film of the first resin film. The first resin film contains a resin having a positive intrinsic birefringence value.

5. The optically anisotropic laminate according to any one of claims 1 to 3, wherein, The first optical anisotropy layer includes a liquid crystal alignment layer.

6. The optically anisotropic laminate according to any one of claims 1 to 3, wherein, The second optical anisotropic layer is a stretched film of the second resin film. The second resin film contains a resin having a negative intrinsic birefringence value.

7. The optically anisotropic laminate according to claim 6, wherein, The second optical anisotropic layer is a stretched film obtained by stretching the second resin film in two directions, wherein NZ2 is greater than -2.0 and less than -0.

2.

8. The optically anisotropic laminate according to any one of claims 1 to 3, wherein, The NZ2 is above -2.0 and below -0.

6.

9. A circular polarizer, comprising: Linear polarizer; and The optically anisotropic laminate according to any one of claims 1 to 8.

10. The circular polarizer according to claim 9, wherein, The angle between the absorption axis or transmission axis of the linear polarizer and the slow axis of the first optical anisotropy layer is 40° to 50°.

11. The circular polarizer according to claim 9 or 10, wherein, The circular polarizer sequentially comprises the linear polarizer, the first optical anisotropic layer, and the second optical anisotropic layer, or The circular polarizer sequentially comprises the linear polarizer, the second optical anisotropic layer, and the first optical anisotropic layer.

12. An image display device comprising a circular polarizer and an organic electroluminescent element as described in any one of claims 9 to 11, The image display device comprises, in sequence, the linear polarizer, the optical anisotropic laminate, and the organic electroluminescent element.

13. A method for manufacturing an optically anisotropic laminate, as described in any one of claims 1 to 8, comprising the following steps: Step 1: Stretch a first resin film containing a resin with a positive intrinsic birefringence value to obtain a first optical anisotropy layer. Step 2 involves stretching a second resin film containing a resin with a negative intrinsic birefringence value to obtain a second optical anisotropy layer. as well as Step 3 involves overlapping the first optical anisotropic layer and the second optical anisotropic layer. In step 1, the first resin film is stretched in one direction. In step 2, the second resin film is stretched in two directions. In step 3, the slow axis of the first optical anisotropy layer is overlapped with the slow axis of the second optical anisotropy layer at an angle of 85° to 95°.

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