Circular polarizing plate

Abstract

To provide a circular polarizing plate that can provide a display device that can operate stably even when the display device equipped with the circular polarizing plate is placed in a high-temperature environment, or when the circular polarizing plate in the display device is shaped or perforated. [Solution] A circular polarizing plate comprising a first phase difference plate, a polarizing plate, and a second phase difference plate in this order, wherein the first phase difference plate comprises a thermoplastic resin layer having a glass transition temperature of 150°C or higher and a tensile modulus of elasticity of 3500 MPa or higher, the polarizing plate comprises a cured layer of a polymerizable liquid crystal composition comprising a polymerizable liquid crystal compound and a dichroic dye, and the second phase difference plate comprises a cured layer of a polymerizable liquid crystal composition comprising a polymerizable liquid crystal compound.

Description

[Technical Field]

[0001] This invention relates to a circular polarizer. [Background technology]

[0002] Conventionally, circular polarizers have been used in various image display panels (displays), such as liquid crystal display panels or organic electroluminescent (OLED) display panels, by being bonded to image display elements such as liquid crystal cells or OLED display elements. Devices that display images, etc. (for example, display devices mounted in automobiles) are required to operate stably in high-temperature environments. As a technology to reduce the change in reflected hue before and after being placed in a high-temperature environment, for example, Patent Document 1 below discloses a circular polarizing plate that includes a protective film A, a polarizing plate, a protective film B, and a phase difference layer in order from the viewing side when incorporated into a display device, wherein the protective film A is a cycloolefin resin stretched film that exhibits a phase difference. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2019-185007 [Overview of the Initiative] [Problems that the invention aims to solve]

[0004] In recent years, the diversification of display designs in display devices has sometimes necessitated shaping or perforation of circular polarizing plates. However, circular polarizing plates subjected to such shaping or perforation may not function stably in high-temperature environments.

[0005] Therefore, an object of the present invention is to provide a circularly polarizing plate that can provide a display device that can operate stably even when a display device equipped with the circularly polarizing plate is placed in a high-temperature environment or when the circularly polarizing plate in the display device is subjected to shape processing, perforation, or the like.

Means for Solving the Problems

[0006] The inventor has conducted intensive studies to solve the above problems. As a result, it has been found that the above problems are solved by a circularly polarizing plate including a specific first retardation plate, a specific polarizing plate, and a specific second retardation plate in this order, and the present invention has been completed.

[0007] That is, the present invention includes the following preferred embodiments. [1] A circularly polarizing plate including a first retardation plate, a polarizing plate, and a second retardation plate in this order, where the first retardation plate includes a thermoplastic resin layer having a glass transition temperature of 150° C. or higher and a tensile elastic modulus of 3500 MPa or higher, the polarizing plate includes a cured product layer of a polymerizable liquid crystal composition containing a polymerizable liquid crystal compound and a dichroic dye, and the second retardation plate includes a cured product layer of a polymerizable liquid crystal composition containing a polymerizable liquid crystal compound, the circularly polarizing plate. [2] The retardation value Re1(550) at a wavelength of 550 nm of the first retardation plate and the retardation value Re2(550) at a wavelength of 550 nm of the second retardation plate satisfy the following formula (1): Re1(550) < Re2(550) Formula (1) The circularly polarizing plate according to [1]. [3] The circularly polarizing plate according to [1] or [2], wherein the thermoplastic resin layer exhibits inverse wavelength dispersion. [4] The first retardation plate includes the thermoplastic resin layer and a retardation film, and the retardation film exhibits positive wavelength dispersion. The circularly polarizing plate according to any one of [1] to [3]. [5] The circularly polarizing plate according to any one of [1] to [4], wherein the cured product layer included in the second retardation plate exhibits inverse wavelength dispersion. [6] The circular polarizer according to any one of [1] to [5], further comprising a cured resin layer on the side of the first phase difference plate opposite to the polarizer side. [7] A circular polarizing plate according to any one of [1] to [6], having a deformed portion within the plane of the circular polarizing plate. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide a circular polarizing plate that can provide a display device that can operate stably even when the display device equipped with the circular polarizing plate is placed in a high-temperature environment, or when the circular polarizing plate in the display device is subjected to shaping or perforation. [Modes for carrying out the invention]

[0009] The embodiments of the present invention will be described in detail below. However, the scope of the present invention is not limited to the embodiments described herein, and various modifications can be made without departing from the spirit of the invention.

[0010] [Circular polarizer] The circular polarizer of the present invention comprises a specific first phase difference plate, a specific polarizer, and a specific second phase difference plate in this order. The inventors have discovered that, unexpectedly, when the circular polarizer of the present invention is applied to a display device, the display device can operate stably even when the display device is placed in a high-temperature environment, or when the circular polarizer in the display device is subjected to shaping or perforation.

[0011] <First retardation plate> Throughout this specification, "phase difference plate" means a film containing a phase difference film or phase difference film, which exhibits optical functionality as a phase difference film or phase difference film. "Phase difference film" means a film that exhibits a phase difference in the in-plane or thickness direction, and the phase difference is formed by stretching a thermoplastic resin film or the like. "Phase difference film" (liquid crystal phase difference film) means a film that exhibits a phase difference in the in-plane or thickness direction, which is either a layer containing a polymerizable liquid crystal compound, or a layer consisting of this layer and an alignment film.

[0012] The first phase difference plate includes a thermoplastic resin layer having a glass transition temperature of 150°C or higher and a tensile modulus of elasticity of 3500 MPa or higher. If this thermoplastic resin layer is a phase difference film, the first phase difference plate includes the thermoplastic resin layer as the layer that exhibits the phase difference. If this thermoplastic resin layer is not a phase difference film, the first phase difference plate includes a phase difference film in addition to the thermoplastic resin layer (which does not exhibit the phase difference) as the layer that exhibits the phase difference. Therefore, if the thermoplastic resin layer is a phase difference film, the first phase difference plate may be a single layer made of the thermoplastic resin layer or a multilayer made of the thermoplastic resin layer and other layers, and if the thermoplastic resin layer is not a phase difference film, it may be a multilayer including the thermoplastic resin layer and a phase difference film.

[0013] The glass transition temperature of the thermoplastic resin layer is 150°C or higher, preferably 155°C or higher, and more preferably 160°C or higher. When the glass transition temperature of the thermoplastic resin layer is above the lower limit, the phase difference plate can have better heat resistance, and the display device incorporating the circular polarizer plate including the phase difference plate can operate stably even in harsh environments. The upper limit of the glass transition temperature of the thermoplastic resin layer is not particularly limited, but is usually 200°C or lower. The glass transition temperature of the thermoplastic resin layer can be adjusted to be above the lower limit, or above the lower limit and below the upper limit, by appropriately selecting the composition of the composition forming the thermoplastic resin layer. The glass transition temperature of the thermoplastic resin layer can be measured using a differential scanning calorimeter (DSC), specifically by the method described in the examples below.

[0014] The tensile modulus of the thermoplastic resin layer is 3500 MPa or higher, preferably 3600 MPa or higher, and more preferably 3700 MPa or higher. When the tensile modulus of the thermoplastic resin layer is above the lower limit, the phase difference plate can have smaller stress strains even in high-temperature environments, so that the display device incorporating the circular polarizer plate including the phase difference plate can operate stably even in harsh environments. The upper limit of the tensile modulus of the thermoplastic resin layer is not particularly limited, but is usually 5000 MPa or lower. The tensile modulus of the thermoplastic resin layer can be adjusted to be above the lower limit, or above the lower limit and below the upper limit, by appropriately selecting the composition of the composition forming the thermoplastic resin layer. The tensile modulus of the thermoplastic resin layer can be measured using a precision universal tester, specifically by the method described in the examples below.

[0015] In order for the first phase difference plate to function as a phase difference plate, the first phase difference plate is defined by the following equations (2) to (4): 90nm ≤ Re1(450) ≤ 130nm (2) 85nm ≤ Re1(550) ≤ 120nm (3) 80nm ≤ Re1(650) ≤ 110nm (4) [In equations (2) to (4), Re1(λ) represents the in-plane phase difference value of the first phase difference plate at a wavelength of λnm.] It is preferable to have a phase difference value that satisfies the following conditions. When the in-plane phase difference Re1(λ) of the first phase difference plate is within the range of equations (2) to (4), the first phase difference plate functions as a quarter-wave plate, and when a circular polarizer plate including the first phase difference plate is applied to a display device, the visibility of the display device can be improved even when the display device is placed in a high-temperature environment, or when the circular polarizer plate in the display device is shaped or perforated. In this specification, the in-plane phase difference value is measured in an environment with a temperature of 23°C and a relative humidity of 55%. A more preferable range for the above in-plane phase difference value is 95nm≦Re1(450)≦110nm, 85nm≦Re1(550)≦105nm, and 85nm≦Re1(650)≦105nm.

[0016] In the first phase difference plate, if the thermoplastic resin layer has a phase difference, the thermoplastic resin layer is preferably a stretched thermoplastic resin film. In this case, the in-plane phase difference of the first phase difference plate can be adjusted within the above range by the stretching rate and / or thickness and / or wavelength dispersion of the thermoplastic resin film. In the first phase difference plate, if the thermoplastic resin layer does not have a phase difference but the phase difference film does, the phase difference film is either a single layer containing a polymerizable liquid crystal compound, or a two-layer layer consisting of this layer and an alignment film. In this case, the in-plane phase difference of the first phase difference plate can be adjusted within the above range by the thickness and / or birefringence of the phase difference film.

[0017] In one embodiment of the present invention, it is preferable that the first phase difference plate does not contain a stretched thermoplastic resin film. By not including a stretched thermoplastic resin film in the first phase difference plate, the crack resistance of the circular polarizer in the present invention can be improved. In this embodiment, the first phase difference plate may include a thermoplastic resin layer without a phase difference and a phase difference film.

[0018] The thickness of the first phase difference plate is preferably 3 to 30 μm, more preferably 5 to 25 μm, from the viewpoint of desired phase difference value and thinness. In the present invention, the thickness of each layer or film can be measured by methods commonly used in the art, such as using a laser microscope, film thickness gauge, ellipsometer, etc.

[0019] (thermoplastic resin layer) When the thermoplastic resin layer contained in the first phase difference plate has a phase difference, the thermoplastic resin layer is preferably a stretched thermoplastic resin film. The thermoplastic resin contained in the stretched thermoplastic resin film is not particularly limited as long as the thermoplastic resin layer has a glass transition temperature of 150°C or higher and a tensile modulus of 3500 MPa or higher. Preferably, the stretched thermoplastic resin film contains, as a resin component, a chain-like polyolefin resin, a cyclic polyolefin resin, a polycarbonate resin, a cellulose resin, a cellulose ester resin, a polyester resin, a (meth)acrylic resin, or two or more of these, and more preferably, the resin component of the stretched thermoplastic resin film consists of one or more selected from these.

[0020] Examples of linear polyolefin resins include homopolymers of linear olefins such as polyethylene resin and polypropylene resin, as well as copolymers composed of two or more linear olefins.

[0021] Cyclic polyolefin resins are a general term for resins in which cyclic olefins are polymerized using cyclic olefins as polymerization units. Examples of cyclic polyolefin resins include ring-opening (co)polymers of cyclic olefins, addition polymers of cyclic olefins, copolymers of cyclic olefins with chain-like olefins such as ethylene or propylene (typically random copolymers), graft polymers modified with unsaturated carboxylic acids or their derivatives, and their hydrides. From the viewpoint of the glass transition temperature and tensile modulus of the thermoplastic resin layer, norbornene resins using norbornene monomers such as norbornene or polycyclic norbornene monomers as the cyclic olefin are preferred.

[0022] Polycarbonate resins consist of polymers in which monomer units are bonded via carbonate groups. Polycarbonate resins may also be modified polycarbonates, which are resins in which the polymer backbone has been modified, or copolymerized polycarbonates, etc.

[0023] Examples of cellulose-based resins include cellulose triacetate and cellulose diacetate.

[0024] Cellulose ester resins are esters of cellulose and fatty acids. Examples of cellulose ester resins include cellulose triacetate (triacetylcellulose: TAC), cellulose diacetate, cellulose trippropionate, and cellulose dipropionate. Copolymers of these, as well as those in which some of the hydroxyl groups are modified with other substituents, can also be used. Among these, cellulose triacetate is particularly preferred from the viewpoint of mechanical properties.

[0025] Polyester resins are resins containing ester bonds, and are generally composed of polycondensates of polycarboxylic acids or their derivatives and polyhydric alcohols. Divalent dicarboxylic acids or their derivatives can be used as polycarboxylic acids or their derivatives; specific examples include terephthalic acid, isophthalic acid, dimethyl terephthalate, and dimethyl naphthalenedicarboxylate. Divalent diols can be used as polyhydric alcohols; specific examples include ethylene glycol, propanediol, butanediol, neopentyl glycol, and cyclohexanedimethanol. Specific examples of polyester resins include polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polytrimethylene terephthalate, polytrimethylene naphthalate, polycyclohexanedimethyl terephthalate, and polycyclohexanedimethyl naphthalate.

[0026] (Meth)acrylic resins are resins whose main constituent monomers are compounds having a (meth)acryloyl group. Specific examples of (meth)acrylic resins include poly(meth)acrylic acid esters such as polymethyl methacrylate; methyl methacrylate-(meth)acrylic acid copolymers; methyl methacrylate-(meth)acrylic acid ester copolymers; methyl methacrylate-acrylic acid ester-(meth)acrylic acid copolymers; methyl methacrylate-styrene copolymers (MS resin, etc.); and copolymers of methyl methacrylate and compounds having an alicyclic hydrocarbon group (for example, methyl methacrylate-cyclohexyl methacrylate copolymer, methyl methacrylate-norbornyl methacrylate copolymer, etc.). Preferably, poly(meth)acrylic acid C such as polymethyl (meth)acrylate is used. 1~6 A polymer mainly composed of alkyl esters is used, and more preferably, a methyl methacrylate resin mainly composed of methyl methacrylate (50-100% by weight, preferably 70-100% by weight) is used.

[0027] The thermoplastic resin layer may optionally contain additives in addition to the thermoplastic resin. Examples of such additives include antioxidants, release agents, stabilizers, bluing agents, flame retardants, pH adjusters, silica dispersants, lubricants, thickeners, leveling agents, and combinations of two or more of these. If the thermoplastic resin layer contains additives, the amount is preferably 0.001 to 20% by mass, more preferably 0.01 to 15% by mass, and even more preferably 0.1 to 10% by mass, relative to the total mass of the thermoplastic resin layer.

[0028] The elongation ratio in the stretched thermoplastic resin film is preferably 1 to 5 times, more preferably 1 to 3 times, and even more preferably 1 to 2 times, from the viewpoint of a desired phase difference value. When the thermoplastic resin layer contained in the first phase difference plate has a phase difference, the thickness of the thermoplastic resin layer is preferably 3 to 30 μm, more preferably 5 to 28 μm, from the viewpoint of desired phase difference value and thinness.

[0029] When the thermoplastic resin layer contained in the first phase difference plate has a phase difference, it is preferable that the thermoplastic resin layer exhibits inverse wavelength dispersion. Inverse wavelength dispersion is an optical property in which the in-plane phase difference value at short wavelengths is smaller than the in-plane phase difference value at long wavelengths, and preferably the thermoplastic resin layer satisfies the following equations (5) and (6). Re1(λ) represents the in-plane phase difference value for light with a wavelength of λnm. Re1(450) / Re1(550)<1.00 (5) 1.00 <Re1(650) / Re1(550) (6) Because the thermoplastic resin layer exhibits inverse wavelength dispersion, when a circular polarizing plate including the first phase difference plate is applied to a display device, the visibility of the display device can be further improved even when the display device is placed in a high-temperature environment, or when the circular polarizing plate in the display device is shaped or perforated.

[0030] From the viewpoint of improving inverse wavelength dispersion and further enhancing the visibility improvement effect of the above-mentioned display device, Re1(450) / Re1(550) is preferably 0.70 or higher, more preferably 0.80 or higher, even more preferably 0.90 or higher, and also preferably 0.99 or lower. Furthermore, Re1(650) / Re1(550) is preferably 1.01 or higher, also preferably 1.20 or lower, more preferably 1.15 or lower, and even more preferably 1.10 or lower. The values ​​of Re1(450) / Re1(550) and Re1(650) / Re1(550) can be adjusted to be above the lower limit and below the upper limit, depending on the elongation rate and / or thickness and / or wavelength dispersion of the thermoplastic resin film.

[0031] Therefore, in this embodiment, it is preferable that the first phase difference plate includes a thermoplastic resin layer having a phase difference, and that the thermoplastic resin layer exhibits reverse wavelength dispersion.

[0032] If the thermoplastic resin layer included in the first phase difference plate does not have a phase difference, the thermoplastic resin layer is preferably a film corresponding to the thermoplastic resin film before stretching of the stretched thermoplastic resin film described above. When the thermoplastic resin layer contained in the first retardation plate has no retardation, the thickness of the thermoplastic resin layer is preferably 3 to 30 μm, more preferably 5 to 28 μm, from the viewpoints of thinness and / or protection.

[0033] The method for producing the thermoplastic resin film and the stretched thermoplastic resin film is not particularly limited and can be produced by a known method.

[0034] (Retardation film) In one embodiment where the thermoplastic resin layer contained in the first retardation plate has no retardation, the first retardation plate includes a retardation film. The retardation film is either a single layer composed of a polymer of a polymerizable liquid crystal compound or a two-layer structure composed of this layer and an alignment film.

[0035] The thickness of the retardation film is preferably 0.1 to 5 μm, more preferably 0.5 to 5 μm, still more preferably 0.5 to 3 μm, and even more preferably 1 to 3 μm, from the viewpoints of the retardation function and thinness. When the retardation film includes an alignment film, the thickness of the alignment film is not included in the thickness of the retardation film.

[0036] The retardation film is preferably a retardation film composed of a "horizontally aligned liquid crystal cured film" in which the polymerizable liquid crystal compound is cured in a state of being horizontally aligned with respect to the plane of the retardation film. This retardation film preferably satisfies the above formulas (7) to (9).

[0037] The retardation film may also be a retardation film that is a positive C plate (nx≒ny < nz) or a retardation film having a 1 / 2 wavelength plate function. The retardation film that is a positive C plate is a "vertically aligned liquid crystal cured film" in which the polymerizable liquid crystal compound is cured in a state of being vertically aligned with respect to the plane of the retardation film. By including a retardation film having a 1 / 4 wavelength plate function and a retardation film that is a positive C plate as the first retardation plate and the second retardation plate in the circular polarizing plate of the present invention, when the circular polarizing plate is applied to an organic EL display device or the like, in addition to improving the front reflection hue, an improvement in the oblique reflection hue can also be expected.

[0038] In the present invention, the polymerizable liquid crystal compound capable of forming a phase difference film can be appropriately selected from polymerizable liquid crystal compounds conventionally known in the field of phase difference films, depending on the desired optical properties. The polymerizable liquid crystal compounds that can be used in the present invention can be classified, for example, into rod-shaped type (rod-shaped liquid crystal compounds) and disc-shaped type (disc-shaped liquid crystal compounds, discotic liquid crystal compounds) based on their shape, and any of these liquid crystal compounds can be used. Furthermore, two or more rod-shaped liquid crystal compounds, two or more disc-shaped liquid crystal compounds, or mixtures of rod-shaped and disc-shaped liquid crystal compounds may also be used.

[0039] Polymerizable liquid crystal compounds are liquid crystal compounds having polymerizable groups. Generally, polymerizable liquid crystal compounds include polymerizable liquid crystal compounds that exhibit positive wavelength dispersibility and polymerizable liquid crystal compounds that exhibit inverse wavelength dispersibility, obtained by polymerizing the polymerizable liquid crystal compound alone while oriented in a specific direction. In the present invention, either one type of polymerizable liquid crystal compound may be used alone, or both types of polymerizable liquid crystal compounds may be used in mixture form.

[0040] In the present invention, the polymerizable groups of the polymerizable liquid crystal compound that form the phase difference film are preferably photopolymerizable groups. A photopolymerizable group is a group that can participate in the polymerization reaction by active radicals or acids generated from a polymerization initiator. Examples of polymerizable groups of the polymerizable liquid crystal compound include vinyl groups, vinyloxy groups, 1-chlorovinyl groups, isopropenyl groups, 4-vinylphenyl groups, acryloyloxy groups, methacryloyloxy groups, oxyranyl groups, and oxetanyl groups. Among these, radical polymerizable groups are preferred, acryloyloxy groups, methacryloyloxy groups, vinyloxy groups, oxyranyl groups, and oxetanyl groups are more preferred, and acryloyloxy groups or methacryloyloxy groups are even more preferred. The liquid crystalline properties exhibited by the polymerizable liquid crystal compound may be thermotropic liquid crystal or lyotropic liquid crystal, but thermotropic liquid crystal is preferred because it allows for precise control of film thickness. Furthermore, the phase order structure in the thermotropic liquid crystal may be nematic, smectic, or discotic liquid crystal. Polymerizable liquid crystal compounds can be used alone or in combination of two or more.

[0041] The phase difference film is defined by the following formula (7): 85nm ≤ Re1(550) ≤ 120nm (7) [In the formula, Re(λ)1 represents the in-plane phase difference value of the phase difference film at a wavelength of λnm.] It is preferable that the following conditions be met. When the in-plane phase difference Re1(550) of the phase difference film is within the range of equation (7), the phase difference film functions as a quarter-wave plate, and when a circular polarizer containing the phase difference film is applied to a display device, the visibility of the display device can be further improved even when the display device is placed in a high-temperature environment, or when the circular polarizer in the display device is shaped or perforated. A more preferred range for the in-plane phase difference value is 85 nm ≤ Re1(550) ≤ 105 nm.

[0042] The phase difference film preferably exhibits positive wavelength dispersion. Positive wavelength dispersion is an optical property in which the in-plane phase difference value at long wavelengths is less than or equal to the in-plane phase difference value at short wavelengths, and preferably the phase difference film satisfies the following equations (8) and (9). Re1(450) / Re1(550)≧1.00 (8) 1.00 ≥ Re1(650) / Re1(550) (9) Because the phase difference film exhibits positive wavelength dispersion, when a circular polarizing plate including the first phase difference plate is applied to a display device, particularly when the first phase difference plate is positioned on the viewing side of the second phase difference plate, the visibility of the display device can be further improved even when the display device is placed in a high-temperature environment, or when the circular polarizing plate in the display device is shaped or perforated.

[0043] From the viewpoint of improving positive wavelength dispersion and further enhancing the visibility-improving effect of the above-mentioned display device, Re1(450) / Re1(550) is preferably 1.30 or less, more preferably 1.20 or less, even more preferably 1.10 or less, and also preferably 1.01 or more. Furthermore, Re1(650) / Re1(550) is 0.90 or more, more preferably 0.92 or more, and even more preferably 0.94 or more. The values ​​of Re1(450) / Re1(550) and Re1(650) / Re1(550) can be adjusted to be above the lower limit and below the upper limit, depending on the intrinsic birefringence value of the resin material used.

[0044] Therefore, in this embodiment, it is preferable that the first phase difference plate includes a thermoplastic resin layer that does not have a phase difference and a phase difference film, and that the phase difference film exhibits positive wavelength dispersion.

[0045] The above in-plane phase difference value can be adjusted by the film thickness dA of the phase difference film. The in-plane phase difference value is given by the following formula: ReA(λ)=(nxA(λ)-nyA(λ))×dA [In the formula, nxA(λ) represents the principal refractive index at wavelength λnm in the plane of the phase difference film, nyA(λ) represents the refractive index at wavelength λnm in the direction perpendicular to the direction of nxA within the same plane as nxA, and dA represents the thickness of the phase difference film.] This is determined by [the following factors]. Therefore, to obtain the desired in-plane phase difference value (ReA(λ): in-plane phase difference value of the phase difference film at wavelength λ(nm)), one should adjust the three-dimensional refractive index and the film thickness dA.

[0046] An example of a polymerizable liquid crystal compound that produces a phase difference film exhibiting positive wavelength dispersion is "Paliocolor® LC242" manufactured by BASF Japan.

[0047] The polymerizable liquid crystal composition for forming a phase difference film (hereinafter also referred to as the "phase difference film forming composition") may contain other polymerizable liquid crystal compounds other than the polymerizable liquid crystal compound that provides positive wavelength dispersion, as long as the effects of the present invention are not impaired. When the phase difference film forming composition contains two or more polymerizable liquid crystal compounds, from the viewpoint of obtaining a phase difference film with excellent optical properties, it is preferable that at least one of them is a polymerizable liquid crystal compound that provides positive wavelength dispersion, and all of the components contained in the phase difference film forming composition may be polymerizable liquid crystal compounds that provide positive wavelength dispersion.

[0048] In the phase difference film-forming composition, the content of the polymerizable liquid crystal compound that provides positive wavelength dispersion is preferably 60 to 99.9% by mass, more preferably 70 to 99.9% by mass, and even more preferably 80 to 99% by mass, relative to the solid content of the phase difference film-forming composition. When the content of the polymerizable liquid crystal compound is within the above range, the orientation of the polymerizable liquid crystal compound tends to be high. In this specification, solid content refers to the total amount of components excluding the solvent from the phase difference film-forming composition. Hereinafter, when solid content refers to the components excluding volatile components such as solvents from the composition in question, it similarly refers to the components excluding volatile components such as solvents.

[0049] The composition for forming a phase difference film may contain a polymerization initiator for initiating the polymerization reaction of a polymerizable liquid crystal compound. The polymerization initiator can be appropriately selected from those conventionally used in the art, and may be either a thermal polymerization initiator or a photopolymerization initiator, but a photopolymerization initiator is preferred because it can initiate the polymerization reaction under lower temperature conditions. The polymerization initiator may be used alone or in combination of two or more types.

[0050] As photopolymerization initiators, known photopolymerization initiators can be used. For example, photopolymerization initiators that generate active radicals include self-cleaving type photopolymerization initiators and hydrogen abstraction type photopolymerization initiators. Self-cleaving photopolymerization initiators include self-cleaving benzoin compounds, acetophenone compounds, hydroxyacetophenone compounds, α-aminoacetophenone compounds, oxime ester compounds, acylphosphine oxide compounds, azo compounds, etc. In addition, hydrogen abstraction type photopolymerization initiators include hydrogen abstraction benzophenone compounds, benzoin ether compounds, benzyl ketal compounds, dibenzosverone compounds, anthraquinone compounds, xanthone compounds, thioxanthone compounds, halogenoacetophenone compounds, dialkoxyacetophenone compounds, halogenobisimidazole compounds, halogenotriazine compounds, triazine compounds, etc.

[0051] Iodonium salts and sulfonium salts can be used as photopolymerization initiators that generate acid.

[0052] In particular, reactions at low temperatures are preferred from the viewpoint of preventing the dissolution of the dye, and self-cleaving photopolymerization initiators are preferred from the viewpoint of reaction efficiency at low temperatures, with acetophenone compounds, hydroxyacetophenone compounds, α-aminoacetophenone compounds, and oxime ester compounds being especially preferred.

[0053] Examples of photopolymerization initiators include the following: Benzoin compounds such as benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, and benzoin isobutyl ether; Hydroxyacetophenone compounds such as oligomers of 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1,2-diphenyl-2,2-dimethoxyethane-1-one, 2-hydroxy-2-methyl-1-[4-(2-hydroxyethoxy)phenyl]propan-1-one, 1-hydroxycyclohexylphenyl ketone, and 2-hydroxy-2-methyl-1-[4-(1-methylvinyl)phenyl]propan-1-one; α-aminoacetophenone compounds such as 2-methyl-2-morpholino-1-(4-methylthiophenyl)propan-1-one and 2-dimethylamino-2-benzyl-1-(4-morpholinophenyl)butan-1-one; Oxime ester compounds such as 1,2-octanedione, 1-[4-(phenylthio)-,2-(O-benzoyl oxime)], ethanone, 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazole-3-yl]-,1-(O-acetyl oxime); Acylphosphine oxide compounds such as 2,4,6-trimethylbenzoyldiphenylphosphine oxide and bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide; Benzophenone compounds such as benzophenone, o-methyl benzoylbenzoate, 4-phenylbenzophenone, 4-benzoyl-4'-methyldiphenyl sulfide, 3,3',4,4'-tetra(tert-butylperoxycarbonyl)benzophenone, and 2,4,6-trimethylbenzophenone; Dialkoxyacetophenone compounds such as diethoxyacetophenone; 2,4-Bis(trichloromethyl)-6-(4-methoxyphenyl)-1,3,5-triazine, 2,4-Bis(trichloromethyl)-6-(4-methoxynaphthyl)-1,3,5-triazine, 2,4-Bis(trichloromethyl)-6-(4-methoxystyryl)-1,3,5-triazine, 2,4-Bis(trichloromethyl)-6-[2-(5-methylfuran-2-yl)ethenyl]-1,3,5- Triazine compounds such as lyazine, 2,4-bis(trichloromethyl)-6-[2-(furan-2-yl)ethenyl]-1,3,5-triazine, 2,4-bis(trichloromethyl)-6-[2-(4-diethylamino-2-methylphenyl)ethenyl]-1,3,5-triazine, and 2,4-bis(trichloromethyl)-6-[2-(3,4-dimethoxyphenyl)ethenyl]-1,3,5-triazine. The photopolymerization initiator can be appropriately selected in relation to the polymerizable liquid crystal compound that forms a phase difference film from the above-mentioned photopolymerization initiator.

[0054] Alternatively, commercially available photopolymerization initiators may be used. Examples of commercially available polymerization initiators include Irgacure (registered trademark) 907, 184, 651, 819, 250 and 369, 379, 127, 754, OXE01, OXE02, OXE03 (manufactured by BASF); Omnirad BCIM, Esacure 1001M, Esacure KIP160 (IDM Resins). Examples include: BV Corporation; Seikaol (registered trademark) BZ, Z, and BEE (manufactured by Seiko Chemical Co., Ltd.); Kayacure (registered trademark) BP100 and UVI-6992 (manufactured by Dow Chemical Ltd.); Adeka Optomer SP-152, N-1717, N-1919, SP-170, Adeka Arclus NCI-831, Adeka Arclus NCI-930 (manufactured by ADEKA Corporation); TAZ-A and TAZ-PP (manufactured by Nippon Siber Hegner Co., Ltd.); and TAZ-104 (manufactured by Sanwa Chemical Co., Ltd.).

[0055] The phase difference film forming composition may optionally contain additives such as leveling agents, polymerizable non-liquid crystal compounds, photosensitizers, antioxidants, mold release agents, stabilizers, colorants such as bluing agents, flame retardants, and lubricants. When such additives are included, the content of the additive is preferably more than 0% and 20% by mass or less, and more preferably more than 0% and 10% by mass or less, relative to the solid content of the phase difference film forming composition.

[0056] Leveling agents have the function of adjusting the fluidity of the phase difference film-forming composition and making the coating obtained by applying the composition flatter. Specifically, surfactants are examples. As the leveling agent, at least one selected from the group consisting of leveling agents mainly composed of polyacrylate compounds and leveling agents mainly composed of fluorine atom-containing compounds is preferred. Leveling agents can be used alone or in combination of two or more types.

[0057] Examples of leveling agents primarily composed of polyacrylate compounds include BYK-350, BYK-352, BYK-353, BYK-354, BYK-355, BYK-358N, BYK-361N, BYK-380, BYK-381, and BYK-392 (BYK Chemie).

[0058] Examples of leveling agents whose main component is a fluorine atom-containing compound include Megafac® R-08, R-30, R-90, F-410, F-411, F-443, F-445, F-470, F-471, F-477, F-479, F-482, F-483 and F-556 (DIC Corporation); Surflon® S-381, S-382, S-383, S-393, SC-101, SC-105, KH-40 and SA-100 (AGC Seimi Chemical Co., Ltd.); E1830, E5844 (Daikin Fine Chemical Laboratories, Inc.); F-Top EF301, F-Top EF303, F-Top EF351 and F-Top EF352 (Mitsubishi Materials Electronic Chemicals Co., Ltd.).

[0059] When the composition for forming a phase difference film contains a leveling agent, its content is preferably 0.01 to 5 parts by mass, more preferably 0.05 to 3 parts by mass, per 100 parts by mass of the polymerizable liquid crystal compound. When the content of the leveling agent is within the above range, the polymerizable liquid crystal compound is easily oriented, unevenness is less likely to occur, and a smoother phase difference film tends to be obtained.

[0060] A composition for forming a phase difference film is prepared, for example, by mixing and stirring a polymerizable liquid crystal compound and, if necessary, a polymerization initiator, additives, etc. Furthermore, to improve coatability, a solvent may be added to the composition for forming the phase difference film to adjust its viscosity. Specifically, the solvents include, for example, alcohol solvents such as methanol, ethanol, ethylene glycol, isopropyl alcohol, propylene glycol, ethylene glycol methyl ether, ethylene glycol butyl ether, and propylene glycol monomethyl ether; ester solvents such as ethyl acetate, butyl acetate, ethylene glycol methyl ether acetate, γ-butyrolactone, or propylene glycol methyl ether acetate and ethyl lactate; and acetone, methyl ethyl ketone, cyclopentanone, cyclohexanone, 2-heptanone, and methyl isobutyl ketone. Examples include ketone solvents such as ton; aliphatic hydrocarbon solvents such as pentane, hexane, and heptane; aromatic hydrocarbon solvents such as toluene and xylene; nitrile solvents such as acetonitrile; ether solvents such as tetrahydrofuran and dimethoxyethane; chlorine-containing solvents such as chloroform and chlorobenzene; amide solvents such as N,N-dimethylacetamide and N,N-dimethylformamide; sulfur-containing solvents such as dimethyl sulfone, dimethyl sulfoxide, and sulfolane; carbonate solvents such as ethylene carbonate and propylene carbonate; and pyrrolidone solvents such as N-methylpyrrolidone. These solvents may be used individually or in combination of two or more.

[0061] The solvent content is preferably 100 to 1900 parts by mass, more preferably 150 to 1000 parts by mass, and even more preferably 180 to 800 parts by mass, per 100 parts by mass of solid content of the phase difference film forming composition.

[0062] A phase difference film can be obtained by applying a phase difference film-forming composition onto a substrate or an alignment film, removing the solvent by drying, and curing the polymerizable liquid crystal compound in the resulting coating film in an oriented state.

[0063] If the substrate is not peeled off afterward, the substrate corresponds to the thermoplastic resin layer without phase difference described above. Therefore, it is preferable that the substrate is the same as the thermoplastic resin film before stretching of the stretched thermoplastic resin film described above. Alternatively, a commercially available thermoplastic resin film having a glass transition temperature of 150°C or higher and a tensile modulus of 3500 MPa or higher may be used as the substrate. The substrate may be subjected to surface treatments such as corona treatment or plasma treatment.

[0064] When the substrate is to be peeled off later, in addition to the above-mentioned substrates that can be used when the substrate is not to be peeled off later, conventionally known resin film substrates in the field of optical films can be used as the substrate. Specifically, examples of resins that constitute such conventionally known resin films include polyolefin resins such as polyethylene and polypropylene; cycloolefin resins such as norbornene polymers; polyester resins such as polyethylene terephthalate and polyethylene naphthalate; poly(meth)acrylic acid resins such as (meth)acrylic acid and poly(meth)acrylate methyl; cellulose ester resins such as triacetylcellulose, diacetylcellulose and cellulose acetate propionate; vinyl alcohol resins such as polyvinyl alcohol and polyvinyl acetate; polycarbonate resins; polystyrene resins; polyarylate resins; polysulfone resins; polyethersulfone resins; polyamide resins; polyimide resins; polyetherketone resins; polyphenylene sulfide resins; polyphenylene oxide resins, and mixtures thereof. These may be used individually or in combination of two or more. Such resins can be formed into a resin film substrate by known means such as solvent casting or melt extrusion. Alternatively, commercially available products may be used as the film substrate or the resin constituting the film substrate. It is preferable that the substrate be treated with a release agent to facilitate subsequent removal of the substrate.

[0065] If the substrate is later peeled off, a laminate can be obtained by laminating the phase difference film with a thermoplastic resin film equivalent to the substrate used when the substrate is not peeled off, as described above, thereby obtaining a laminate containing a phase difference film and a thermoplastic resin layer having a predetermined glass transition temperature and tensile modulus. The lamination of the phase difference film and the thermoplastic resin layer can be performed, for example, via a lamination layer formed from an adhesive.

[0066] The bonding layer is a layer formed from an adhesive. The bonding layer is not particularly limited as long as it can function as a layer for bonding a phase difference film to a thermoplastic resin layer having a predetermined glass transition temperature and tensile modulus, and may be a layer formed from a known adhesive. The adhesive is not particularly limited, and conventionally known adhesives and glues can be used without particular restriction. Examples of adhesives include adhesives having a base polymer such as acrylic, rubber, urethane, silicone, or polyvinyl ether. Energy ray curing adhesives and thermosetting adhesives may also be used. Examples of glues include active energy ray curing adhesives, water-based adhesives, organic solvent-based adhesives, and solvent-free adhesives.

[0067] In one embodiment of the present invention, it is preferable to use an adhesive as the adhesive for bonding the phase difference film and a thermoplastic resin layer having a predetermined glass transition temperature and tensile modulus. Using an adhesive as the adhesive for bonding the phase difference film and the thermoplastic resin layer having a predetermined glass transition temperature and tensile modulus can improve the crack resistance of the circular polarizer of the present invention and reduce the reflectance in the display device. This effect of reducing reflectance can be further improved when the circular polarizer of the present invention is incorporated into a display device and the first phase difference plate is positioned on the viewing side of the second phase difference plate. The reflectance can be evaluated by the method described in the examples below.

[0068] The thickness of the laminated layer is preferably 1 to 10 μm, more preferably 1.5 to 8 μm, from the viewpoint of sufficient bonding strength between adjacent layers and the thinness of the circular polarizing plate.

[0069] The thickness of the substrate is not particularly limited and can be selected appropriately within a practical range. For example, it can be around 5 μm to 300 μm.

[0070] The phase difference film may include an alignment film. The alignment film has an orientation-regulating force that causes polymerizable liquid crystal compounds to be liquid crystal-aligned in a desired direction, and a phase difference film (cured layer) with high precision can be easily obtained by applying a phase difference film-forming composition onto the alignment film. The alignment film is preferably solvent-resistant, not dissolved by the application of the phase difference film-forming composition, and also has heat resistance for solvent removal and heat treatment for the orientation of the polymerizable liquid crystal compounds. Furthermore, it is preferable that the difference in refractive index between the phase difference film or the laminated layer is small.

[0071] Examples of orientation films include orientation films containing orientation polymers, photo-alignment films, groove-alignment films having surface irregularities or multiple grooves, and stretched films stretched in the orientation direction. These various orientation films can be appropriately selected from those conventionally known in the field, depending on the desired orientation restricting force.

[0072] In one embodiment of the present invention, a photo-alignment film is preferred from the viewpoint of improving orientation accuracy and adhesion with the cured layer formed from the phase difference film forming composition. The photo-alignment film is also advantageous in that the direction of the orientation restricting force can be arbitrarily controlled by selecting the polarization direction of the irradiated polarized light.

[0073] Photo-alignment films are typically obtained by applying a composition containing a polymer, oligomer, or monomer having a photoreactive group and a solvent (hereinafter also referred to as the "photo-alignment film forming composition") onto a substrate or the like, and irradiating it with polarized light (preferably polarized UV). If the polymer or the like contained in the photo-alignment film forming composition has the same reactive group (for example, a (meth)acryloyl group) as the polymerizable group of the polymerizable liquid crystal compound that forms the phase difference film, the adhesion between the cured layer of the polymerizable liquid crystal compound and the alignment film tends to improve. As the substrate to which the photo-alignment film-forming composition is applied, the same substrate that can be used for applying the phase difference film-forming composition can be used.

[0074] A photoreactive group is a group that generates liquid crystal alignment ability upon light irradiation. Specifically, this includes groups involved in photoreactions that are the origin of liquid crystal alignment ability, such as molecular orientation induction or isomerization reactions, dimerization reactions, photocrosslinking reactions, or photodegradation reactions, which are induced by light irradiation. Among these, groups involved in dimerization reactions or photocrosslinking reactions are preferred because they exhibit excellent orientation properties. As a photoreactive group, groups having unsaturated bonds, especially double bonds, are preferred, and groups having at least one selected from the group consisting of carbon-carbon double bonds (C=C bonds), carbon-nitrogen double bonds (C=N bonds), nitrogen-nitrogen double bonds (N=N bonds), and carbon-oxygen double bonds (C=O bonds) are particularly preferred.

[0075] Specifically, such alignment films can be photo-alignment films, such as those described in Japanese Patent Publication No. 2020-56834 and Japanese Patent Publication No. 2021-196514.

[0076] The thickness of the orientation film is preferably 10 to 3000 nm, more preferably 10 to 1000 nm, even more preferably 10 to 500 nm, even more preferably 10 to 300 nm, and particularly preferably 30 to 300 nm. When the thickness of the orientation film is within the above range, it is possible to exhibit good adhesion at the interface with the cured layer formed from the phase difference film forming composition formed on the orientation film, while also exhibiting orientation order, thereby forming a phase difference film with high orientation order.

[0077] The method for applying the phase difference film formation composition and the photo-alignment film formation composition onto a substrate or alignment film is not particularly limited, and known methods such as spin coating, extrusion, gravure coating, die coating, bar coating, applicator coating, and printing methods such as flexographic coating can be employed.

[0078] When a phase difference film-forming composition contains a solvent, or when a photo-alignment film-forming composition normally contains a solvent, the solvent is usually removed from the applied composition. Methods for removing the solvent include natural drying, forced-air drying, heat drying, and reduced-pressure drying. Preferably, the dried film is dried so that the residual solvent in the coating film is 1% by weight or less of the total mass of the coating film. The amount of residual solvent can be quantified by peeling the coating film from the substrate, weighing it, immersing the coating film in a solvent that dissolves the coating film, such as tetrahydrofuran, irradiating it with ultrasound for about 10 minutes to extract the dissolved components, and then analyzing this solution by gas chromatography. Each condition, such as drying temperature and drying time, can be appropriately determined depending on the composition of the phase difference film-forming composition or the alignment film-forming composition, the materials of the substrate and the alignment film, etc.

[0079] In a composition for forming a phase difference film, the polymerizable liquid crystal compound in the coating film is typically heated to a temperature above which it transitions to a liquid crystal state or a solution state, and then cooled to a temperature at which liquid crystal orientation occurs, thereby orienting and forming a liquid crystal phase.

[0080] The temperature at which the polymerizable liquid crystal compound in the coating of the phase difference film-forming composition aligns can be determined in advance by observing the texture of the composition containing the polymerizable liquid crystal compound. Alternatively, solvent removal and liquid crystal orientation may be performed simultaneously. The temperature at this time depends on the solvent to be removed and the type of polymerizable liquid crystal compound used, but is preferably in the range of 50 to 200°C, and more preferably in the range of 80 to 130°C.

[0081] A phase difference film is formed as a cured layer of the liquid crystal composition by polymerizing and curing the polymerizable liquid crystal compound while maintaining its liquid crystal state. Photopolymerization is preferred as the polymerization method. In photopolymerization, the light irradiated onto the dried film is appropriately selected according to the type of polymerizable liquid crystal compound contained in the dried film (particularly the type of polymerizable group the polymerizable liquid crystal compound has), the type of polymerization initiator, and their amounts.

[0082] (Thermoplastic resin layer and any phase difference film and / or layers other than the laminate layer) The first phase difference plate may include a thermoplastic resin layer, a phase difference film and / or a laminating layer if present, as well as other additional layers.

[0083] Such further layers include, for example, a coating layer (surface treatment layer) whether or not the thermoplastic resin layer included in the first phase difference plate has a phase difference. Specific examples of coating layers include a hard coat layer, an anti-glare layer, an anti-reflective layer, an anti-static layer, and an anti-fouling layer. A single coating layer may have two or more functions (for example, a hard coat function and an anti-fouling function). The thickness of the coating layer is not particularly limited, but is usually 0.5 to 100 μm, preferably 1 to 10 μm. The coating layer can be included at any location on the first phase difference plate, but it is preferable to place it adjacent to the thermoplastic resin layer if the thermoplastic resin layer has a phase difference, and adjacent to the thermoplastic resin layer or the phase difference film included in the first phase difference plate if the thermoplastic resin layer does not have a phase difference. The method for forming the coating layer is not particularly limited, and known methods can be used. The coating layer may be formed by coating an adjacent layer (e.g., a thermoplastic resin layer or a phase difference film), or the coating layer may be formed separately and then bonded. Such bonding can be performed, for example, via a bonding layer formed from an adhesive. This bonding layer may be similar to the bonding layer described above for joining a phase difference film to a thermoplastic resin layer having a predetermined glass transition temperature and tensile modulus.

[0084] • Hard coat layer (sometimes referred to as the "HC layer" below) The HC layer can be formed by curing an HC layer-forming composition containing a reactive material that forms a crosslinked structure by irradiation with active energy rays or thermal energy, but it is preferable that the HC layer-forming composition is cured by irradiation with active energy rays (cured resin layer). In one embodiment of the present invention, it is preferable to further include a cured resin layer on the side of the first phase difference plate opposite to the polarizing plate side.

[0085] Active energy rays are defined as energy rays that can decompose compounds that generate active species, thereby generating those active species themselves. Examples of active energy rays include visible light, ultraviolet light, infrared light, X-rays, alpha rays, beta rays, gamma rays, and electron beams. Of these, ultraviolet light is particularly preferred.

[0086] The HC layer forming composition contains at least one radical polymerizable compound and a cationic polymerizable compound.

[0087] A radical polymerizable compound is a compound having a radical polymerizable group. The radical polymerizable group of a radical polymerizable compound can be any functional group capable of undergoing a radical polymerization reaction, and examples include groups containing a carbon-carbon unsaturated double bond. Specifically, examples include vinyl groups and (meth)acryloyl groups. When the radical polymerizable compound has two or more radical polymerizable groups, these radical polymerizable groups may be the same or different. From the viewpoint of improving the hardness of the HC layer, it is preferable that the number of radical polymerizable groups in one molecule of a radical polymerizable compound is two or more.

[0088] As radical polymerizable compounds, compounds having (meth)acryloyl groups are preferred from the viewpoint of high reactivity. For example, compounds referred to as polyfunctional acrylate monomers having 2 to 6 (meth)acryloyl groups in one molecule, or oligomers with molecular weights of several hundred to several thousand having several (meth)acryloyl groups in the molecule, referred to as epoxy (meth)acrylate, urethane (meth)acrylate, and polyester (meth)acrylate, can be preferably used. It is preferable that one or more selected from epoxy (meth)acrylate, urethane (meth)acrylate, and polyester (meth)acrylate are included in the HC layer forming composition.

[0089] Cationic polymerizable compounds are compounds having cationic polymerizable groups such as epoxy groups, oxetanyl groups, and vinyl ether groups. From the viewpoint of improving the hardness of the HC layer, the number of cationic polymerizable groups in one molecule of a cationic polymerizable compound is preferably two or more, and more preferably three or more. Furthermore, as cationic polymerizable compounds, compounds having at least one of epoxy groups and oxetanyl groups as cationic polymerizable groups are preferred.

[0090] Cyclic ether groups such as epoxy groups and oxetanyl groups are preferred from the viewpoint of minimizing shrinkage during polymerization reactions. Furthermore, compounds containing epoxy groups among cyclic ether groups have the advantage of being readily available in a variety of structures, not adversely affecting the durability of the resulting HC layer, and being easy to control in terms of compatibility with radical polymerizable compounds.

[0091] Furthermore, among the cyclic ether groups, the oxetanyl group tends to have a higher degree of polymerization compared to the epoxy group, is less toxic, accelerates the network formation rate obtained from the cationic polymerizable compounds in the resulting HC layer, and has advantages such as forming an independent network without leaving unreacted monomers in the HC layer even in regions where it is mixed with radical polymerizable compounds.

[0092] Examples of cationic polymerizable compounds having epoxy groups include: alicyclic epoxy resins obtained by epoxidizing polyglycidyl ethers of polyhydric alcohols having alicyclic rings, and compounds containing cyclohexene or cyclopentene rings, with a suitable oxidizing agent such as hydrogen peroxide or a peracid; aliphatic epoxy resins such as polyglycidyl ethers of aliphatic polyhydric alcohols or their alkylene oxide adducts, polyglycidyl esters of aliphatic long-chain polybasic acids, and homopolymers or copolymers of glycidyl (meth)acrylates; glycidyl ethers produced by the reaction of bisphenols such as bisphenol A, bisphenol F, or hydrogenated bisphenol A, or derivatives thereof such as alkylene oxide adducts or caprolactone adducts, with epichlorohydrin; novolac epoxy resins; and glycidyl ether-type epoxy resins derived from bisphenols.

[0093] The HC layer-forming composition may further contain a polymerization initiator. Examples of polymerization initiators include radical polymerization initiators, cationic polymerization initiators, and radical and cationic polymerization initiators, which can be appropriately selected and used. These polymerization initiators are decomposed by at least one of active energy ray irradiation and heating to generate radicals or cations, thereby promoting radical polymerization and cationic polymerization.

[0094] A radical polymerization initiator is any agent that can release a substance that initiates radical polymerization by at least one of active energy ray irradiation and heating. Examples of active energy ray radical polymerization initiators include Type 1 radical polymerization initiators, which generate radicals through molecular decomposition, and Type 2 radical polymerization initiators, which generate radicals in a hydrogen abstraction reaction in the presence of tertiary amines. These can be used individually or in combination. Examples of thermal radical polymerization initiators include organic peroxides such as hydrogen peroxide and perbenzoic acid, as well as azo compounds such as azobisbutyronitrile, which can be used individually or in combination.

[0095] A cationic polymerization initiator can be any agent capable of releasing a substance that initiates cationic polymerization upon irradiation with active energy rays and heating, or at least one of these. Examples of cationic polymerization initiators include aromatic iodonium salts, aromatic sulfonium salts, and cyclopentadienyl iron(II) complexes. Depending on their structure, these can initiate cationic polymerization by either or both irradiation with active energy rays and / or heating.

[0096] If the HC layer-forming composition contains a polymerization initiator, its content is preferably 0.1 to 10% by mass relative to the total mass of the HC layer-forming composition. If the polymerization initiator content is above the lower limit, the curing of the HC layer-forming composition can be sufficiently promoted, and the resulting HC layer can have the desired mechanical properties or adhesion. If the polymerization initiator content is below the upper limit, poor adhesion, cracking, or curling due to curing shrinkage can be suppressed.

[0097] The HC layer-forming composition may further comprise one or more selected from the group consisting of solvents and additives (other than polymerization initiators). The solvent should be capable of dissolving or dispersing polymerizable compounds and polymerization initiators (if present), and such solvents are known in the art. Examples of additives include inorganic particles, leveling agents, stabilizers, surfactants, antistatic agents, lubricants, and antifouling agents, one or more of which can be incorporated into the HC layer-forming composition.

[0098] By including a hard coat layer in the first phase difference plate, the mechanical strength of the first phase difference plate can be improved, and thus the mechanical strength of the circular polarizer can be improved.

[0099] In the present invention, layers necessary for ensuring, maintaining, and / or reinforcing the function of the first phase difference plate as a phase difference film or phase difference layer, as well as layers formed integrally with the phase difference layer, specifically, for example, a thermoplastic resin layer, a phase difference layer, a hard coat layer adjacent to or near the phase difference layer, and a bonding layer for bonding these layers, are considered to be components constituting the first phase difference plate. On the other hand, in the present invention, a bonding layer for bonding the first phase difference plate to another layer such as a polarizing plate is not usually considered a component of the first phase difference plate or the polarizing plate.

[0100] <Polarizing plate> The polarizer included in the circular polarizer of the present invention includes a cured layer of a polymerizable liquid crystal composition containing a polymerizable liquid crystal compound and a dichroic dye. The cured layer corresponds to a polarizing film. The polarizing film may be a single layer or a multilayer of two or more layers made of the cured polymerizable liquid crystal composition, or a multilayer of one or more layers made of the cured polymerizable liquid crystal composition and one or more layers of an alignment film for forming the layer. Preferably, the polarizing film is a horizontal polarizing film (hereinafter also simply referred to as a "horizontal polarizing film" or "linear polarizing film") in which the polymerizable liquid crystal compound and the dichroic dye are cured in a state in which they are oriented horizontally with respect to the polarizing film plane. A horizontal polarizing film usually allows light vibrating in the direction of the transmission axis to pass through, but has the function of blocking the polarization of vibration components perpendicular to it, and functions as a polarizing film that extracts linearly polarized light from incident natural light.

[0101] The thickness of the polarizing film is preferably 0.1 to 5 μm, more preferably 0.5 to 4 μm, even more preferably 1 to 3.5 μm, and particularly preferably 1.5 to 3.3 μm, from the viewpoint of polarizing function and thinness. The thickness of the polarizing film is the thickness of the layer made of the cured polymerizable liquid crystal composition contained in the polarizing film, and if the polarizing film has an alignment film, the thickness of the alignment film is not included in the thickness of the polarizing film.

[0102] A polarizing film-forming composition for forming a polarizing film will be described. The polymerizable liquid crystal compound contained in the polarizing film-forming composition is a compound having at least one polymerizable group and having liquid crystallinity. Here, the polymerizable group means a group involved in a polymerization reaction, and is preferably a photopolymerizable group. Examples of the photopolymerizable group include the same ones as those exemplified as the polymerizable group that the polymerizable liquid crystal compound for forming a retardation film may have.

[0103] The polymerizable liquid crystal compound is preferably a liquid crystal compound exhibiting smectic liquid crystallinity. By using a polymerizable liquid crystal compound exhibiting a smectic liquid crystal phase, a polarizing film having a high degree of alignment order and excellent in polarizing function can be formed. From the viewpoint of realizing a higher degree of alignment order, the liquid crystal state exhibited by the polymerizable liquid crystal compound is more preferably a higher-order smectic phase (higher-order smectic liquid crystal state). Here, the higher-order smectic phase means a smectic B phase, a smectic D phase, a smectic E phase, a smectic F phase, a smectic G phase, a smectic H phase, a smectic I phase, a smectic J phase, a smectic K phase, and a smectic L phase. Among these, the smectic B phase, the smectic F phase, and the smectic I phase are more preferable, and the smectic B phase is even more preferable. The liquid crystallinity may be thermotropic liquid crystal or lyotropic liquid crystal, but thermotropic liquid crystal is preferable in terms of enabling precise film thickness control. Further, the polymerizable liquid crystal compound may be a monomer, but may also be an oligomer or a polymer in which the polymerizable groups are polymerized.

[0104] Examples of such a polymerizable liquid crystal compound include a compound represented by formula (A) (hereinafter, also referred to as "polymerizable liquid crystal compound (A)"). U 1 -V 1 -W 1 -(X 1 -Y 1 ) n -X 2 -W 2 -V 2 -U 2 (A)

[0105] In formula (A), X 1 and X 2 Each independently represents a divalent aromatic group or a divalent alicyclic hydrocarbon group, where the hydrogen atoms in the divalent aromatic group or divalent alicyclic hydrocarbon group may be substituted with substituents selected from the group consisting of halogen atoms, C1-C4 alkyl groups, C1-C4 fluoroalkyl groups, C1-C4 alkoxy groups, cyano groups, and nitro groups, and the carbon atoms constituting the divalent aromatic group or divalent alicyclic hydrocarbon group may be substituted with oxygen atoms, sulfur atoms, or nitrogen atoms. However, X 1 and X 2 At least one of these is a 1,4-phenylene group which may have the above substituent, or a cyclohexane-1,4-diyl group which may have the above substituent. Y 1 It is a single bond or a divalent linking group. n is 1 to 3, and if n is 2 or greater, multiple X 1 They may be the same or they may be different. 2 is multiple X 1 It may be the same as or different from any or all of the following. Also, if n is 2 or more, there may be multiple Y 1 These values ​​may be the same or different. From the viewpoint of liquid crystalline properties, n is preferably 2 or greater. U 1 represents a hydrogen atom or a polymerizable group. U 2 This represents a polymerizable group. W 1 and W 2 These are, independently of each other, single or divalent linking groups. V 1 and V 2 Each of these independently represents an alkanediyl group having 1 to 20 carbon atoms, which may have substituents, and the -CH2- constituting the alkanediyl group may be replaced with -O-, -CO-, -S-, or -NH-.

[0106] In polymerizable liquid crystal compound (A), X 1and X 2 These are, independently of each other, preferably a substituted 1,4-phenylene group or a substituted cyclohexane-1,4-diyl group, X 1 and X 2 At least one of these is an optionally substituted 1,4-phenylene group or an optionally substituted cyclohexane-1,4-diyl group, preferably a trans-cyclohexane-1,4-diyl group. Optional substituents on the optionally substituted 1,4-phenylene group or the optionally substituted cyclohexane-1,4-diyl group include C1-C4 alkyl groups such as methyl, ethyl, and butyl groups, cyano groups, and halogen atoms such as chlorine and fluorine atoms. It is preferably unsubstituted.

[0107] Furthermore, polymerizable liquid crystal compound (A) is a compound of formula (A1): -(X 1 -Y 1 ) n -X 2 - (A1) [In the formula, X 1 , Y 1 , X 2 And n have the same meaning as above. From the viewpoint of exhibiting smectic liquid crystal properties, it is preferable that the portion indicated by (hereinafter referred to as "substructure (A1)") has an asymmetric structure. A polymerizable liquid crystal compound (A) in which the substructure (A1) is an asymmetric structure is, for example, n is 1 and one X 1 and X 2 A polymerizable liquid crystal compound (A) in which the two have different structures is also an example. 1 Compounds in which two X have the same structure 1 They have the same structure as each other, and one X 2 These two X 1 Polymerizable liquid crystal compound (A) has a different structure from two X 1 W 1 X that binds 1 However, the other X 1and X 2 It has a different structure, and the other X 1 and X 2 Another example is a polymerizable liquid crystal compound (A) which has the same structure as the others. Furthermore, n is 3, and there are three Y 1 Compounds in which the three X's are identical in structure 1 and one X 2 A polymerizable liquid crystal compound (A) is one in which one of the structures is different from all three others.

[0108] Y 1 -CH2CH2-, -CH2O-, -CH2CH2O-, -COO-, -OCOO-, single bond, -N=N-, -CR a =CR b -, -C≡C-, -CR a =N- or -CO-NR a - is preferable. a and R b Each of these independently represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. 1 It is more preferably -CH2CH2-, -COO-, or a single bond, and multiple Y 1 If X 2 Y that combines with 1 It is more preferable that it be -CH2CH2- or -CH2O-. 1 and X 2 If all have the same structure, then two or more Y have different bonding methods. 1 It is preferable that multiple Ys with different coupling methods exist. 1 When present, an asymmetric structure is formed, which tends to lead to the development of smectic liquid crystal properties.

[0109] U 2 U is a polymerizable group. 1 is a hydrogen atom or a polymerizable group, preferably a polymerizable group. 1 and U 2It is preferable that both are polymerizable groups, and more preferably that both are radical polymerizable groups. Examples of polymerizable groups include vinyl group, vinyloxy group, 1-chlorovinyl group, isopropenyl group, 4-vinylphenyl group, (meth)acryloyl group, (meth)acryloyloxy group, oxyranyl group, oxetanyl group, etc. Among these, radical polymerizable groups are preferred, (meth)acryloyl group, vinyl group, vinyloxy group are more preferred, and (meth)acryloyl group and (meth)acryloyloxy group are even more preferred. 1 Polymerizable group shown and U 2 The polymerizable groups indicated by the symbols may be different from each other, but it is preferable that they be of the same type. Furthermore, the polymerizable groups may be in a polymerized state or an unpolymerized state, but it is preferable that they be in an unpolymerized state.

[0110] V 1 and V 2 Examples of alkanediyl groups represented by include methylene group, ethylene group, propane-1,3-diyl group, butane-1,3-diyl group, butane-1,4-diyl group, pentane-1,5-diyl group, hexane-1,6-diyl group, heptane-1,7-diyl group, octane-1,8-diyl group, decane-1,10-diyl group, undecane-1,11-diyl group, tetradecane-1,14-diyl group, and eicosan-1,20-diyl group. 1 and V 2 The group is preferably an alkanediyl group having 2 to 12 carbon atoms, and more preferably an alkanediyl group having 6 to 12 carbon atoms.

[0111] The alkanediyl group may optionally have substituents such as cyano groups and halogen atoms, but it is preferable that the alkanediyl group be unsubstituted, and more preferably that it be an unsubstituted linear alkanediyl group.

[0112] W 1 and W 2 These are preferably single bonds, -O-, -S-, -COO-, or -OCOO-, and more preferably single bonds or -O-.

[0113] A structure that readily exhibits smectic liquid crystal properties is preferably one that has an asymmetric molecular structure. Specifically, polymerizable liquid crystal compounds having the structures shown by formulas (Aa) to (Ai) below readily exhibit smectic liquid crystal properties and are suitable as polymerizable liquid crystal compound (A). Furthermore, from the viewpoint of readily exhibiting higher-order smectic liquid crystal properties, it is more preferable to have the structures shown by formulas (Aa), (Ab), or (Ac). In formulas (Aa) to (Ai) below, * represents a bond (single bond).

[0114] [ka]

[0115] Examples of polymerizable liquid crystal compounds (A) include those represented by formulas (A-1) to (A-25). When polymerizable liquid crystal compound (A) has a cyclohexane-1,4-diyl group, it is preferable that the cyclohexane-1,4-diyl group is in trans form.

[0116] [ka]

[0117] [ka]

[0118] [ka]

[0119] Among these, at least one selected from the group consisting of compounds represented by formulas (A-2), (A-3), (A-4), (A-5), (A-6), (A-7), (A-8), (A-13), (A-14), (A-15), (A-16), and (A-17) is preferred. As the polymerizable liquid crystal compound (A), one type may be used alone, or two or more types may be used in combination.

[0120] Polymerizable liquid crystal compound (A) can be produced by known methods described in Lub et al., Recl. Trav. Chim. Pays-Bas, 115, 321-328 (1996), or Japanese Patent No. 4719156, etc.

[0121] The polarizing film-forming composition may contain other polymerizable liquid crystal compounds other than polymerizable liquid crystal compound (A), as long as the effects of the present invention are not impaired. From the viewpoint of obtaining a polarizing film with a high degree of orientation order, the ratio of polymerizable liquid crystal compound (A) to the total mass of all polymerizable liquid crystal compounds in the polarizing film-forming composition is preferably 51% by mass or more, more preferably 70% by mass or more, and even more preferably 90% by mass or more, and may be entirely (100% by mass) polymerizable liquid crystal compound (A).

[0122] When the polarizing film-forming composition contains two or more polymerizable liquid crystal compounds, it is preferable that at least one of them is polymerizable liquid crystal compound (A), and it is also possible that all of the components in the polarizing film-forming composition are polymerizable liquid crystal compounds (A).

[0123] The content of polymerizable liquid crystal compounds in the polarizing film-forming composition is preferably 40 to 99.9% by mass, more preferably 60 to 99.9% by mass, and even more preferably 70 to 99% by mass, relative to the solid content of the polarizing film-forming composition. When the content of polymerizable liquid crystal compounds is within the above range, the orientation of the polymerizable liquid crystal compounds tends to be high.

[0124] The polarizing film-forming composition further contains a dichroic dye. Here, a dichroic dye means a dye that has different absorbances in the long axis direction and in the short axis direction of the molecule. The dichroic dye is not particularly limited as long as it has the above properties, and may be a dye or a pigment. Two or more dyes or pigments may be used in combination, or a dye and a pigment may be used in combination. Dichroic dyes may be used alone or in combination, but in order to obtain absorption across the entire visible light spectrum, it is preferable to combine two or more dichroic dyes, and more preferably to combine three or more dichroic dyes. In particular, by mixing two or more dichroic dyes with different absorption wavelengths, polarizing films of various hues can be produced, and polarizing films that have absorption across the entire visible light spectrum can be obtained.

[0125] The dichroic dye is preferably one that has the property of absorbing visible light, and has a maximum absorption wavelength (λ) in the range of 300 to 700 nm. MAX Dichroic dyes are preferred. Examples of such dichroic dyes include acridine dyes, oxazine dyes, cyanine dyes, naphthalene dyes, azo dyes, and anthraquinone dyes. Among these, azo dyes are preferred.

[0126] Examples of azo dyes include monoazo dyes, bisazo dyes, trisazo dyes, tetrakisazo dyes, and stilbenazo dyes, with bisazo dyes and trisazo dyes being preferred. For example, the compound represented by formula (I) (hereinafter also referred to as "compound (I)") is an example.

[0127] K 1 (-N=NK 2 ) p -N=NK 3 (I) [In formula (I), K 1 and K 3 These independently represent an optionally substituted phenyl group, an optionally substituted naphthyl group, an optionally substituted phenyl benzoate group, or an optionally substituted monovalent heterocyclic group. 2represents a p-phenylene group which may have a substituent, a naphthalene-1,4-diyl group which may have a substituent, a 4,4'-stilbenylene group which may have a substituent, or a divalent heterocyclic group which may have a substituent. p represents an integer from 0 to 4. When p is an integer of 2 or more, a plurality of K 2 may be the same as or different from each other. In the range showing absorption in the visible region, the -N=N- bond may be replaced by a -C=C-, -COO-, -NHCO-, or -N=CH- bond.]

[0128] Examples of the monovalent heterocyclic group include a group obtained by removing one hydrogen atom from a heterocyclic compound such as quinoline, thiazole, benzothiazole, thienothiazole, imidazole, benzimidazole, oxazole, benzoxazole, etc. Examples of the divalent heterocyclic group include a group obtained by removing two hydrogen atoms from the heterocyclic compound.

[0129] K 1 and K 3 The phenyl group, naphthyl group, phenyl benzoate group, and monovalent heterocyclic group in, and the p-phenylene group, naphthalene-1,4-diyl group, 4,4'-stilbenylene group, and divalent heterocyclic group in K 2 The optional substituents include an alkyl group having 1 to 20 carbon atoms, an alkyl group having 1 to 20 carbon atoms and a polymerizable group, an alkenyl group having 1 to 4 carbon atoms; an alkoxy group having 1 to 20 carbon atoms such as a methoxy group, an ethoxy group, a butoxy group, etc.; an alkoxy group having 1 to 20 carbon atoms and a polymerizable group; an alkyl fluoride group having 1 to 4 carbon atoms such as a trifluoromethyl group; a cyano group; a nitro group; a halogen atom; a substituted or unsubstituted amino group such as an amino group, a diethylamino group, a pyrrolidino group, etc. (A substituted amino group means an amino group having one or two alkyl groups having 1 to 6 carbon atoms, an amino group having one or two alkyl groups having 1 to 6 carbon atoms and a polymerizable group, or an amino group in which two substituted alkyl groups are bonded to each other to form an alkanediyl group having 2 to 8 carbon atoms. An unsubstituted amino group is -NH2.) etc. Examples of the polymerizable group include a (meth)acryloyl group, a (meth)acryloyloxy group, etc.

[0130] Among the compounds (I), the compounds represented by any of the following formulas (I-1) to (I-8) are preferred.

Chemical formula

[0131] As the anthraquinone dye, the compound represented by formula (I-9) is preferred.

Chemical formula

[0132] As the oxazine dye, a compound represented by formula (I-10) is preferred. [ka] [In formula (I-10), R 9 ~R 15 These are, independently of each other, hydrogen atoms, -R x -NH2, -NHR x , -NR x 2, -SR x Alternatively, it represents a halogen atom. R x This represents an alkyl group with 1 to 6 carbon atoms or an aryl group with 6 to 12 carbon atoms.

[0133] As the acridine dye, a compound represented by formula (I-11) is preferred. [ka] [In formula (I-11), R 16 ~R 23 These are, independently of each other, hydrogen atoms, -R x -NH2, -NHR x , -NR x 2, -SR x Alternatively, it represents a halogen atom. R x This represents an alkyl group with 1 to 6 carbon atoms or an aryl group with 6 to 12 carbon atoms. In equations (I-9), (I-10), and (I-11), R x Examples of alkyl groups having 1 to 6 carbon atoms include methyl, ethyl, propyl, butyl, pentyl, and hexyl groups, while examples of aryl groups having 6 to 12 carbon atoms include phenyl, toluyl, xylyl, and naphthyl groups.

[0134] As the cyanine dye, compounds represented by formula (I-12) and compounds represented by formula (I-13) are preferred. [ka] [In formula (I-12), D 1 and D 2 These represent, independently of each other, a base represented by any of the formulas (I-12a) to (I-12d). [ka] n5 represents an integer between 1 and 3. [ka] [In formula (I-13), D 3 and D 4 These represent, independently of each other, a base expressed by any of the formulas (I-13a) to (I-13h). [ka] n6 represents an integer between 1 and 3.

[0135] The weight-average molecular weight of dichroic dyes is typically 300 to 2000, preferably 400 to 1000.

[0136] The content of the dichroic dye in the polarizing film-forming composition can be appropriately determined depending on the type of dichroic dye used, but is preferably 1 to 60% by mass, more preferably 1 to 20% by mass, and even more preferably 1 to 15% by mass, relative to the solid content of the polarizing film-forming composition. When the content of the dichroic dye is within the above range, it is less likely to disrupt the orientation of the polymerizable liquid crystal compound, and a polarizing film with a high degree of orientation order can be obtained.

[0137] The polarizing film-forming composition may contain a polymerization initiator. The polymerization initiator is a compound capable of initiating a polymerization reaction, such as a polymerizable liquid crystal compound. Examples of polymerization initiators are the same as those previously exemplified for use in forming a phase difference film.

[0138] The content of the polymerization initiator is preferably 0.1 to 20 parts by mass, more preferably 0.1 to 15 parts by mass, even more preferably 0.5 to 10 parts by mass, and particularly preferably 0.5 to 8 parts by mass, per 100 parts by mass of the polymerizable liquid crystal compound. When the content of the polymerization initiator is within the above range, the polymerization reaction can be carried out without significantly disrupting the orientation of the polymerizable liquid crystal compound.

[0139] The polarizing film forming composition may contain a leveling agent. Examples of leveling agents are the same as those previously exemplified for use in forming a phase difference film.

[0140] When the polarizing film-forming composition contains a leveling agent, its content is preferably 0.01 to 5 parts by mass, more preferably 0.05 to 3 parts by mass, per 100 parts by mass of the polymerizable liquid crystal compound. When the leveling agent content is within the above range, the polymerizable liquid crystal compound is easily oriented, unevenness is less likely to occur, and a smoother polarizing film tends to be obtained.

[0141] The polarizing film-forming composition may contain additives other than leveling agents. Examples of other additives include polymerizable non-liquid crystal compounds, photosensitizers, antioxidants, mold release agents, stabilizers, colorants such as bluing agents, flame retardants, and lubricants. When other additives are included, the content of the other additives is preferably more than 0% and 20% by mass or less, and more preferably more than 0% and 10% by mass or less, relative to the solid content of the polarizing film-forming composition.

[0142] The polarizing film-forming composition can be prepared by conventionally known methods for preparing liquid crystal compositions, and is typically prepared by mixing and stirring a polymerizable liquid crystal compound and a dichroic dye, as well as a polymerization initiator and the above-mentioned additives as needed. Furthermore, since liquid crystal compounds that generally exhibit smectic liquid crystal properties have high viscosity, viscosity adjustment may be performed by adding a solvent to the composition to improve the coatability of the liquid crystal composition and facilitate the formation of a polarizing film.

[0143] The solvent can be appropriately selected according to the solubility of the polymerizable liquid crystal compound and dichroic dye used, and it is preferable that the solvent be able to completely dissolve the components and is inert to the polymerization reaction. Specific examples of solvents include those similar to those previously exemplified for use in forming a phase difference film.

[0144] The solvent content is preferably 100 to 1900 parts by mass, more preferably 150 to 1000 parts by mass, and even more preferably 180 to 800 parts by mass, per 100 parts by mass of solid content of the polarizing film forming composition.

[0145] In the present invention, the cured layer formed from the polarizing film-forming composition is preferably a liquid crystal cured film with a high degree of orientational order. A liquid crystal cured film with a high degree of orientational order yields Bragg peaks derived from higher-order structures such as the hexatic phase and the crystal phase in X-ray diffraction measurements. A Bragg peak refers to a peak derived from the periodic plane structure of molecular orientation. Therefore, it is preferable that the polarizing film (cured layer) constituting the polarizer of the present invention exhibits a Bragg peak in X-ray diffraction measurements. That is, in the present invention, it is preferable that the polymerizable liquid crystal compound or its polymer in the polarizing film (cured layer) is oriented such that the film exhibits a Bragg peak in X-ray diffraction measurements. In one embodiment of the present invention, it is preferable that the periodic plane spacing of the molecular orientation is 3.0 to 6.0 Å. A high degree of orientational order that exhibits a Bragg peak can be achieved by controlling the type of polymerizable liquid crystal compound used, the type and amount of dichroic dye, and the type and amount of polymerization initiator.

[0146] In the present invention, the polarizing film may include an alignment film. Examples of alignment films are the same as those previously exemplified for use in forming a phase difference film.

[0147] Polarizing films are, for example, To form a coating film of a polarizing film-forming composition, Removing the solvent from the aforementioned coating film, The polymerizable liquid crystal compound is heated to a temperature above the temperature at which it undergoes a phase transition to the liquid phase, and then cooled to cause the polymerizable liquid crystal compound to undergo a phase transition to the liquid crystal phase (e.g., smectic liquid crystal phase), and Polymerizing a polymerizable liquid crystal compound while retaining the liquid crystal phase. It can be manufactured by a method that includes [a specific component].

[0148] The polarizing film-forming composition can be formed, for example, by applying the polarizing film-forming composition to a substrate or an alignment film. The substrate can be a layer constituting the polarizing plate of the present invention, but in one embodiment of the present invention, it is preferable that it is ultimately peeled off. Examples of substrates include those similar to those previously exemplified as those that can be used when forming a phase difference film.

[0149] The coating method for the polarizing film-forming composition and the curing conditions using active energy rays are all similar to those that can be used in the method for producing a phase difference film.

[0150] The polarizing plate may include additional layers besides the polarizing film. Examples of such further layers include a hard coat layer, an overcoat layer, an anti-reflective layer, an anti-fouling layer, a gas barrier layer, a hue adjustment layer, and a refractive index adjustment layer. Each of these further layers may possess two or more functions (for example, a hard coat function and an anti-fouling function). The hard coat layer can be the same as the hard coat layer that may be included in the first phase difference plate. The overcoat layer can be formed from a composition (overcoat layer forming composition) that is excellent in terms of solventability, transparency, mechanical strength, thermal stability, shielding properties, and isotropy. Examples of materials constituting the overcoat layer include photocurable resins or water-soluble polymers, and (meth)acrylic resins, polyvinyl alcohol resins, polyamide epoxy resins, etc. can be used. The thickness of the overcoat layer may be, for example, 0.1 μm to 10 μm.

[0151] The method for forming further layers, such as a hard coat layer or an overcoat layer, is not particularly limited, and known methods can be used. A hard coat layer or an overcoat layer may be formed by applying a hard coat layer forming composition or an overcoat layer forming composition to a polarizing film, or a hard coat layer or an overcoat layer may be formed on a substrate and a polarizing film may be formed thereon, or the polarizing film and the further layer may be formed separately and then bonded together. Such bonding can be performed, for example, via a bonding layer formed from an adhesive. This bonding layer may be the same as the bonding layer described above for joining a phase difference film and a thermoplastic resin layer having a predetermined glass transition temperature and tensile modulus. The above substrate can be a layer constituting the polarizing plate of the present invention, but in one embodiment of the present invention, it is preferable that it is ultimately peeled off. Examples of substrates include those similar to those previously exemplified for use when forming a phase difference film.

[0152] When laminating the polarizing plate onto the first phase difference plate, it is preferable to laminate them such that the absorption axis of the polarizing film and the slow phase axis (optical axis) of the first phase difference plate are substantially 45° apart. By laminating them such that the absorption axis of the polarizing film and the slow phase axis (optical axis) of the first phase difference plate are substantially 45° apart, the function of a circular polarizing plate can be obtained. Note that substantially 45° is usually in the range of 45 ± 5°. The bonding of the polarizing plate and the first phase difference plate can be performed, for example, via a bonding layer formed from an adhesive. This bonding layer may be the same as the bonding layer described above for bonding the phase difference film and a thermoplastic resin layer having a predetermined glass transition temperature and tensile modulus.

[0153] In one embodiment of the present invention, it is preferable to use an adhesive as the adhesive used to bond the polarizing plate and the first phase difference plate. Using an adhesive as the adhesive used to bond the polarizing plate and the first phase difference plate can reduce the reflectance of the display device. This effect of reducing reflectance can be further improved when the circular polarizing plate of the present invention is incorporated into a display device and the first phase difference plate is positioned on the viewing side of the second phase difference plate.

[0154] <Second retardation plate> In addition to the first retardation plate and the polarizing plate, the circular polarizing plate of the present invention includes a second retardation plate. The second retardation plate includes a cured product layer of a polymerizable liquid crystal composition containing a polymerizable liquid crystal compound. In the second retardation plate, the cured product layer corresponds to a retardation film. The retardation film is either a layer (the cured product layer) consisting solely of a polymer of a polymerizable liquid crystal compound or a layer composed of two layers of this layer and an alignment film. In the present invention, the bonding layer for bonding the second retardation plate to other layers such as a polarizing plate is not regarded as a component of the second retardation plate or the polarizing plate.

[0155] In order for the second retardation plate to function as a retardation plate, the second retardation plate satisfies the following formulas (10) to (12): 90 nm ≤ Re2(450) ≤ 140 nm (10) 110 nm ≤ Re2(550) ≤ 170 nm (11) 120 nm ≤ Re2(650) ≤ 180 nm (12) [In formulas (10) to (12), Re2(λ) represents the in-plane retardation value of the second retardation plate at a wavelength of λ nm] Preferably, it has a retardation value that satisfies the above. When the in-plane retardation Re2(λ) of the second retardation plate is within the range of formulas (10) to (12), the second retardation plate becomes a retardation plate that functions as a quarter-wave plate. When a circular polarizing plate including the second retardation plate is applied to a display device, even when the display device is placed in a high-temperature environment or when the circular polarizing plate in the display device is subjected to shape processing or perforation, etc., the visibility of the display device can be improved. A more preferable range of the above in-plane retardation value is 80 nm ≤ Re2(450) ≤ 130 nm, 100 nm ≤ Re2(550) ≤ 160 nm, and 125 nm ≤ Re2(650) ≤ 170 nm.

[0156] The cured product layer contained in the second retardation plate may exhibit either positive wavelength dispersion or negative wavelength dispersion.

[0157] In one embodiment of the present invention, the cured product layer included in the second retardation plate preferably exhibits inverse wavelength dispersion, and more preferably satisfies the following formulas (13) and (14). Here, Re2(λ) represents the in-plane retardation value for light with a wavelength of λ nm. Re2(450) / Re2(550) < 1 (13) 1 < Re2(650) / Re2(550) (14) When the cured product layer included in the second retardation plate exhibits inverse wavelength dispersion, when a circular polarizing plate including the second retardation plate is applied to a display device, particularly when the first retardation plate is applied so as to be located closer to the viewing side than the second retardation plate, even when the display device is placed in a high-temperature environment, and also when the circular polarizing plate in the display device is subjected to shape processing or punching, etc., the visibility of the display device can be further improved.

[0158] From the viewpoint of improving the inverse wavelength dispersion and further enhancing the visibility improvement effect of the above-described display device, Re2(450) / Re2(550) is preferably 0.70 or more, more preferably 0.80 or more, still more preferably 0.83 or more, and is preferably 0.99 or less. Also, Re2(650) / Re2(550) is preferably 1.01 or more, and is preferably 1.50 or less, more preferably 1.30 or less, still more preferably 1.20 or less.

[0159] The in-plane retardation value or the ratio thereof can be adjusted in the same manner as the in-plane retardation value or the ratio thereof in the above-described first retardation plate.

[0160] The retardation film is preferably a retardation film composed of a "horizontally aligned liquid crystal cured film" in which a polymerizable liquid crystal compound is cured in a state of being horizontally aligned with respect to the plane of the retardation film. This retardation film preferably satisfies the above formulas (10) to (12). The retardation film may also be a retardation film that is a positive C-plate (nx ≈ ny < nz), or a retardation film having a half-wave plate function.

[0161] In one embodiment of the present invention, the phase difference value Re1(550) of the first phase difference plate at a wavelength of 550 nm and the phase difference value Re2(550) of the second phase difference plate at a wavelength of 550 nm are given by the following formula (1): Re1(550) <Re2(550) (1) It is preferable that the above formula (1) is satisfied. When the circular polarizing plate of the present invention is applied to a display device, the visibility of the display device can be further improved even when the display device is placed in a high-temperature environment, or when the circular polarizing plate in the display device is shaped or perforated.

[0162] As the polymerizable liquid crystal compound for forming the phase difference film included in the second phase difference plate, the same one as described above for the first phase difference plate can be used, and the polymerizable liquid crystal compound described below can also be used. The components that the phase difference film included in the second phase difference plate may optionally contain, the alignment film and further layers that may be included in the second phase difference plate, the preparation of the composition for forming the phase difference film, and the formation of the phase difference film can be the same as those described above for the first phase difference plate.

[0163] Examples of polymerizable liquid crystal compounds that form the phase difference film contained in the second phase difference plate (hereinafter also referred to as "polymerizable liquid crystal compound (B)") include compounds that satisfy all of the following conditions (a) to (d) from the viewpoint of imparting the phase difference properties represented by formulas (13) and (14).

[0164] (a) It is a compound that has thermotropic liquid crystal properties. (i) The polymerizable liquid crystal compound has π electrons along the long axis (a). (c) It has π electrons in a direction intersecting the longitudinal axis (a) [intersecting direction (b)]. (e) The π electron density in the long axis direction (a) of a polymerizable liquid crystal compound defined by the following formula (i), where N(πa) is the total number of π electrons present in the long axis direction (a) and N(Aa) is the total molecular weight present in the long axis direction: D(πa)=N(πa) / N(Aa) (i) The π electron density in the cross direction (b) of a polymerizable liquid crystal compound defined by the following formula (ii), where N(πb) is the total number of π electrons present in the cross direction (b) and N(Ab) is the total molecular weight present in the cross direction (b): D(πb) = N(πb) / N(Ab) (ii) Toga, 0 ≤ [D(πa) / D(πb)] ≤ 1 The relationship is as follows: [that is, the π electron density in the intersecting direction (b) is greater than the π electron density in the long axis direction (a)]. Furthermore, polymerizable liquid crystal compound (B) that satisfies all of the above conditions (a) to (d) can form a nematic or smectic phase by heating it to a temperature above the phase transition temperature, for example. In the nematic or smectic phase formed by the orientation of this polymerizable liquid crystal compound, the long axes of the polymerizable liquid crystal compounds are usually oriented parallel to each other, and these long axes become the orientation direction of the nematic or smectic phase.

[0165] Polymerizable liquid crystal compounds (B) having the above characteristics generally exhibit inverse wavelength dispersion. Specifically, a compound that satisfies the above characteristics (a) to (d) is, for example, the following formula (B1): [ka] Examples of compounds represented by the formula (B1) are shown. The compounds represented by the formula (B1) can be used alone or in combination of two or more.

[0166] In formula (B1), Ar represents a divalent group having an aromatic group which may have substituents. Examples of aromatic groups include those exemplified by (Ar-1) to (Ar-23) described later. Ar may also have two or more aromatic groups. These aromatic groups may contain at least one of the following atoms: nitrogen, oxygen, or sulfur. If Ar contains two or more aromatic groups, these groups may be bonded to each other by single bonds, divalent bonds such as -CO-O- or -O-.

[0167] In formula (B1), G 1 and G2 Each of these independently represents a divalent aromatic group or a divalent alicyclic hydrocarbon group. Here, the hydrogen atoms contained in the divalent aromatic group or divalent alicyclic hydrocarbon group may be substituted with halogen atoms, C1-C4 alkyl groups, C1-C4 fluoroalkyl groups, C1-C4 alkoxy groups, cyano groups, or nitro groups, and the carbon atoms constituting the divalent aromatic group or divalent alicyclic hydrocarbon group may be substituted with oxygen atoms, sulfur atoms, or nitrogen atoms.

[0168] In formula (B1), L 1 , L 2 B 1 and B 2 Each of these is independently a single bond or a divalent linking group.

[0169] In equation (B1), k and l each represent integers from 0 to 3 independently, satisfying the relationship 1 ≤ k + l. Here, if 2 ≤ k + l, then B 1 and B 2 , G 1 and G 2 These elements may be identical to each other, or they may be different.

[0170] In formula (B1), E 1 and E 2 Each of these independently represents an alkanediyl group having 1 to 17 carbon atoms, with an alkanediyl group having 4 to 12 carbon atoms being more preferred. Furthermore, the hydrogen atoms in the alkanediyl group may be substituted with halogen atoms, and the -CH2- in the alkanediyl group may be substituted with -O-, -S-, or -C(=O)-.

[0171] In formula (B1), P 1 and P 2 Each of these independently represents a polymerizable group or a hydrogen atom, and at least one of them is a polymerizable group.

[0172] G 1 and G 2is, independently of each other, preferably a 1,4-phenylene diyl group which may be substituted with at least one substituent selected from the group consisting of a halogen atom and an alkyl group having 1 to 4 carbon atoms, a 1,4-cyclohexane diyl group which may be substituted with at least one substituent selected from the group consisting of a halogen atom and an alkyl group having 1 to 4 carbon atoms, more preferably a 1,4-phenylene diyl group substituted with a methyl group, an unsubstituted 1,4-phenylene diyl group, or an unsubstituted 1,4-trans-cyclohexane diyl group, particularly preferably an unsubstituted 1,4-phenylene diyl group or an unsubstituted 1,4-trans-cyclohexane diyl group. Also, at least one of the plurality of Gs 1 and G 2 is preferably a divalent alicyclic hydrocarbon group. Also, L 1 or L 2 The G bonded to 1 and G 2 Among them, it is more preferable that at least one is a divalent alicyclic hydrocarbon group.

[0173] L 1 [[ID=X]]and L 2 are each independently, preferably a single bond, an alkylene group having 1 to 4 carbon atoms, -O-, -S-, -R a1 OR a2 -, -R a3 COOR a4 -, -R a5 OCOR a6 -, -R a7 OC=OOR a8 -, -N=N-, -CR c =CR d -, or -C≡C-. Here, R a1 ~R a8 each independently represents a single bond or an alkylene group having 1 to 4 carbon atoms, and R c and R d represent an alkyl group having 1 to 4 carbon atoms or a hydrogen atom. L 1 and L [[ID=X]] 2 are each independently, more preferably a single bond, -OR a2-1 -, -CH2-, -CH2CH2-, -COOR It should be noted that in the original text, there is an unclear "X" marked in the translation. Please check and correct it according to the actual situation.a4-1 -, or -OCOR a6-1 - is the case here R a2-1 , R a4-1 , R a6-1 Each of these independently represents either a single bond, -CH2-, or -CH2CH2-. 1 and L 2 Each of these is independently, and more preferably, a single bond, -O-, -CH2CH2-, -COO-, -COOCH2CH2-, or -OCO-.

[0174] B 1 and B 2 Each of these is independently, preferably a single bond, an alkylene group having 1 to 4 carbon atoms, -O-, -S-, -R a9 Ure a10 -, -R a11 COOR a12 -, -R a13 OCOR a14 -, or -R a15 OC=OOR a16 - is the case here R a9 ~R a16 Each of these independently represents a single bond or an alkylene group with 1 to 4 carbon atoms. 1 and B 2 Each is independently, more preferably a single bond, -OR a10-1 -, -CH2-, -CH2CH2-, -COOR a12-1 -, or -OCOR a14-1 - is the case here R a10-1 , R a12-1 , R a14-1 Each of these independently represents either a single bond, -CH2-, or -CH2CH2-. 1 and B 2 Each of these is independently, and more preferably, a single bond, -O-, -CH2CH2-, -COO-, -COOCH2CH2-, -OCO-, or -OCOCH2CH2-.

[0175] k and l are preferably in the range of 2 ≤ k + l ≤ 6 from the viewpoint of inverse wavelength dispersion, preferably k + l = 4, and more preferably k = 2 and l = 2. k = 2 and l = 2 is preferred because it results in a symmetric structure. When k is 2 or greater, two B 1 The two Gs may be the same or different. 1 They may be the same or different. If l is 2 or greater, then there are two B 2 The two Gs may be the same or different. 2 They can be the same or different.

[0176] P 1 or P 2 Examples of polymerizable groups represented by include epoxy groups, vinyl groups, vinyloxy groups, 1-chlorovinyl groups, isopropenyl groups, 4-vinylphenyl groups, (meth)acryloyl groups, oxyranyl groups, and oxetanyl groups. Among these, (meth)acryloyl groups, vinyl groups, and vinyloxy groups are preferred, with (meth)acryloyl groups being more preferred.

[0177] It is preferable that Ar has at least one selected from an aromatic hydrocarbon ring which may have substituents, an aromatic heterocycle which may have substituents, and an electron-withdrawing group. Examples of the aromatic hydrocarbon ring include a benzene ring, a naphthalene ring, an anthracene ring, etc., with benzene rings and naphthalene rings being preferred. Examples of the aromatic heterocycle include a furan ring, a benzofuran ring, a pyrrole ring, an indole ring, a thiophene ring, a benzothiophene ring, a pyridine ring, a pyrazine ring, a pyrimidine ring, a triazole ring, a triazine ring, a pyrroline ring, a pyrodazole ring, an imidazole ring, a pyrazole ring, a thiazole ring, a benzothiazole ring, a thienothiazole ring, an oxazole ring, a benzoxazole ring, and a phenantholine ring, etc. Among these, it is preferable to have a thiazole ring, a benzothiazole ring, or a benzofuran ring, and it is even more preferable to have a benzothiazole ring. Furthermore, if Ar contains a nitrogen atom, it is preferable that the nitrogen atom has π electrons.

[0178] In formula (B1), the total number of π electrons possessed by the group represented by Ar is N. π It is usually 6 or more, preferably 8 or more, more preferably 10 or more, even more preferably 14 or more, and particularly preferably 16 or more. Also, it is preferably 36 or less, more preferably 32 or less, even more preferably 26 or less, and particularly preferably 24 or less.

[0179] Examples of aromatic groups contained in Ar include the following groups:

[0180] [ka]

[0181] In equations (Ar-1) to (Ar-23), the asterisk (*) indicates a connecting part, Z 0 , Z 1 and Z 2 Each of these independently represents a hydrogen atom, a halogen atom, a C1-C12 alkyl group, a cyano group, a nitro group, a C1-C12 alkylsulfinyl group, a C1-C12 alkylsulfonyl group, a carboxyl group, a C1-C12 fluoroalkyl group, a C1-C12 alkoxy group, a C1-C12 alkylthio group, a C1-C12 N-alkylamino group, a C2-C12 N,N-dialkylamino group, a C1-C12 N-alkylsulfamoyl group, or a C2-C12 N,N-dialkylsulfamoyl group. 0 , Z 1 and Z 2 It may contain polymerizable groups.

[0182] In formula (Ar-1) ~ formula (Ar-23), Q 1 and Q 2 Each of these is independently of -CR 2’ R 3’ -, -S-, -NH-, -NR 2’ - represents -CO- or -O-, R 2’ and R 3’ Each of these independently represents either a hydrogen atom or an alkyl group having 1 to 4 carbon atoms.

[0183] In formula (Ar-1) ~ formula (Ar-23), J 1 and J 2 Each of these independently represents either a carbon atom or a nitrogen atom.

[0184] In formula (Ar-1) ~ formula (Ar-23), Y 1 , Y 2 and Y 3 Each of these independently represents an optionally substituted aromatic hydrocarbon group or an aromatic heterocyclic group.

[0185] In equations (Ar-1) to (Ar-23), W 1 and W 2 Each of these independently represents a hydrogen atom, a cyano group, a methyl group, or a halogen atom, and m represents an integer from 0 to 6.

[0186] Y 1 , Y 2 and Y 3 Examples of aromatic hydrocarbon groups in this context include C6-C20 aromatic hydrocarbon groups such as phenyl, naphthyl, anthuryl, phenanthuryl, and biphenyl groups, with phenyl and naphthyl groups being preferred and phenyl groups being more preferred. Examples of aromatic heterocyclic groups include C4-C20 aromatic heterocyclic groups containing at least one heteroatom such as a nitrogen atom, oxygen atom, or sulfur atom, such as furyl, pyrrolyl, thienyl, pyridinyl, thiazolyl, and benzothiazolyl groups, with furyl, thienyl, pyridinyl, thiazolyl, and benzothiazolyl groups being preferred.

[0187] Y 1 , Y 2 and Y 3 Each of these may independently be a substituted polycyclic aromatic hydrocarbon group or a polycyclic aromatic heterocyclic group. A polycyclic aromatic hydrocarbon group refers to a fused polycyclic aromatic hydrocarbon group or a group derived from an aromatic ring assembly. A polycyclic aromatic heterocyclic group refers to a fused polycyclic aromatic heterocyclic group or a group derived from an aromatic ring assembly.

[0188] Z 0 , Z1 and Z 2 Each of these is preferably independently a hydrogen atom, a halogen atom, a C1-C12 alkyl group, a cyano group, a nitro group, or a C1-C12 alkoxy group, Z 0 A hydrogen atom, an alkyl group having 1 to 12 carbon atoms, and a cyano group are more preferably Z 1 and Z 2 Hydrogen atoms, fluorine atoms, chlorine atoms, methyl groups, and cyano groups are more preferred. Also, Z 0 , Z 1 and Z 2 It may contain polymerizable groups.

[0189] Q 1 and Q 2 -NH-, -S-, -NR 2’ -, -O- is preferred, R 2’ A hydrogen atom is preferred. Among these, -S-, -O-, and -NH- are particularly preferred.

[0190] Among equations (Ar-1) to (Ar-23), equations (Ar-10) and (Ar-11) are particularly preferred.

[0191] In equations (Ar-16) to (Ar-23), Y 1 This is the nitrogen atom and Z that it bonds to. 0 It may also form an aromatic heterocyclic group. Examples of aromatic heterocyclic groups that Ar may have include those mentioned above, such as a pyrrole ring, imidazole ring, pyrroline ring, pyridine ring, pyrazine ring, pyrimidine ring, indole ring, quinoline ring, isoquinoline ring, purine ring, pyrrolidine ring, etc. This aromatic heterocyclic group may have substituents. Also, Y 1 This is the nitrogen atom and Z that it bonds to. 0 In addition, the aforementioned substituted polycyclic aromatic hydrocarbon groups or polycyclic aromatic heterocyclic groups may also be used. Examples include benzofuran rings, benzothiazole rings, and benzoxazole rings.

[0192] The compound represented by formula (B1) can be produced, for example, by the method described in Japanese Patent Publication No. 2010-31223.

[0193] The thickness of the phase difference film included in the second phase difference plate is preferably 0.1 to 5 μm, more preferably 0.5 to 5 μm, even more preferably 0.5 to 3 μm, and even more preferably 1 to 3 μm, from the viewpoint of phase difference function and thinness. If the phase difference film includes an orientation film, the thickness of the orientation film is not included in the thickness of the phase difference film.

[0194] When laminating the polarizing plate onto the second phase difference plate, it is preferable to laminate them such that the absorption axis of the polarizing film and the slow phase axis (optical axis) of the second phase difference plate are substantially 45° apart. By laminating them such that the absorption axis of the polarizing film and the slow phase axis (optical axis) of the second phase difference plate are substantially 45° apart, the function of a circular polarizing plate can be obtained. The polarizing plate and the second phase difference plate can be bonded together, for example, via a bonding layer formed from an adhesive. The adhesive used can be the same type of adhesive that can be used to bond the polarizing plate and the first phase difference plate.

[0195] <Any layer> The circular polarizer of the present invention may optionally include one or more additional layers in addition to the first phase difference plate, the polarizer, and the second phase difference plate. Examples of such additional layers include a bonding layer for bonding the first phase difference plate and the polarizer, and a bonding layer for bonding the polarizer and the second phase difference plate. Furthermore, layers that do not impair the function of the circular polarizer may be included, and such layers may include a bonding layer for bonding such layers to the first phase difference plate, the polarizer, and / or the second phase difference plate. The bonding layer may be the same as the bonding layer for bonding the polarizer and the first phase difference plate.

[0196] In one embodiment of the present invention, the circular polarizer has one or more irregularly shaped processed portions within its surface. In this specification, "irregularly shaped processed portion" refers to a portion processed into a special shape different from a general processed shape (for example, chamfering of corners). Typical examples of irregularly shaped processed portions include through holes and machined portions that become recesses when viewed from above. The shape of the through hole is not particularly limited and may be, for example, circular, elliptical, rounded rectangle, or capsule-shaped. Typical examples of recesses include V-shaped notches and U-shaped notches. If the circular polarizer has multiple irregularly shaped processed portions, they may be the same or different from each other. Generally, cracks tend to occur in such irregularly shaped processed parts. The circular polarizing plate of the present invention, by including a specific first phase difference plate, a specific polarizing plate, and a specific second phase difference plate in this order, can exhibit improved crack resistance (particularly crack resistance when processing irregularly shaped parts and / or crack resistance after durability tests such as heat shock tests).

[0197] The shaped section can be placed at any appropriate location depending on the purpose. Typically, the shaped section is placed at or near the end of the circular polarizing plate.

[0198] The circular polarizing plate of the present invention can provide a display device that can operate stably even when the display device equipped with the circular polarizing plate is placed in a high-temperature environment, or when the circular polarizing plate in the display device is subjected to shaping or perforation. Furthermore, in one embodiment of the present invention, the reflectivity of the display device can be reduced. Therefore, the circular polarizing plate of the present invention is suitable as a component of various display devices. A display device is a device having a display element, and includes a light-emitting element or light-emitting device as a light source. Examples of display devices include liquid crystal displays, organic electroluminescent (EL) displays, inorganic electroluminescent (EL) displays, touch panel displays, electron emission displays (e.g., electric field emission displays (FEDs), surface field emission displays (SEDs)), electronic paper (display devices using electronic ink or electrophoretic elements), plasma displays, projection displays (e.g., grating light bulb (GLV) displays, displays with digital micromirror devices (DMDs)), and piezoelectric ceramic displays. Liquid crystal displays include transmissive liquid crystal displays, semi-transmissive liquid crystal displays, reflective liquid crystal displays, and direct-view liquid crystal displays. This includes both crystal display devices and projection-type liquid crystal display devices. These display devices may be two-dimensional display devices or three-dimensional display devices that display three-dimensional images. In particular, the circular polarizing plate of the present invention can be suitably used in organic electroluminescent (EL) display devices and inorganic electroluminescent (EL) display devices, and can also be suitably used in liquid crystal display devices and touch panel display devices. These display devices, including the circular polarizing plate of the present invention, can operate stably even when placed in a high-temperature environment, and even when the circular polarizing plate in the display device is shaped or perforated.

[0199] In one embodiment of the present invention, it is preferable that the first phase difference plate is positioned on the viewing side of the second phase difference plate in the display device. In this embodiment, the display device can operate more stably even when the display device including the circular polarizing plate of the present invention is placed in a high-temperature environment, or when the circular polarizing plate in the display device is subjected to shaping or perforation. In this embodiment, from the viewpoint of the mechanical strength of the surface of the circular polarizer, it is preferable that the circular polarizer includes a hard coat layer on the outermost surface opposite to the side of the first phase difference plate on which the polarizer is laminated. In this embodiment, if the circular polarizer includes at least one bonded layer, it is preferable that at least one of the bonded layers is formed from an adhesive (i.e., an adhesive layer), and it is more preferable that the entire bonded layer is an adhesive layer. In this embodiment, the reflectance of the display device including the circular polarizer of the present invention can be reduced. This reflectance reduction effect can be further improved when the first phase difference plate is positioned on the viewing side of the second phase difference plate when the circular polarizer of the present invention is incorporated into the display device.

[0200] The present invention will be described in more detail below with reference to examples and comparative examples, but the present invention is not limited to these examples. Hereinafter, parts and percentages representing usage amounts and content are based on mass unless otherwise specified. [Examples]

[0201] [measurement] [Thickness] The thickness of the layers or films was measured using a laser microscope (Olympus Corporation's "LEXT") or a digital micrometer (Nikon Corporation's "MH-15M").

[0202] [Glass transition temperature] The glass transition temperature (Tg) [°C] of a thermoplastic resin film was measured using a differential scanning calorimeter (Seiko Instruments "EXSTAR6000 series DSC6220").

[0203] [Tensile modulus of elasticity] The tensile modulus was determined according to JIS K 7161-1 using a Shimadzu Autograph "AG-IS". The sample was cut to a width of 10 mm and a length of 50 mm (excluding the chuck), and a uniaxial tensile test was performed at a speed of 1 mm / min. The tensile modulus was calculated from the slope of the resulting stress-strain curve.

[0204] [Storage modulus of the adhesive layer] Multiple adhesive layers were stacked to a thickness of 0.2 mm (measured with a digital micrometer (Nikon Corporation "MH-15M")), and then a cylindrical body with a diameter of 8 mm was punched out and used as a measurement sample. The storage modulus G' [kPa] of this measurement sample was measured using the torsional shear method in accordance with JIS K7244-6 using a viscoelasticity measuring device (Physica Corporation "MCR300") under the following conditions. <Measurement conditions> Normal Force FN:1N Distortion γ: 1% Frequency: 1Hz Temperature: 25℃

[0205] [Pencil Hardness Test] The pencil hardness of the first phase difference plate used below was measured in accordance with JIS K5600-5-4 using a No. 553-M pencil scratch hardness tester manufactured by Yasuda Seiki Seisakusho.

[0206] [Preparation of Active Energy Ray Curable Compositions (Cationic Polymerizable Adhesive Compositions)] After mixing the components listed below, the mixture was degassed to prepare an active energy ray curable composition. The photocationic polymerization initiator was included as a 50% propylene carbonate solution, and its amount is indicated in solid content. • Cationic polymerizable compound (1) [3-ethyl-3{[(3-ethyloxetan-3-yl)methoxy]methyl}oxetane (trade name: OXT-221, manufactured by Toagosei Co., Ltd.)]: 60.0 parts • Cationic polymerizable compound (2) [3',4'-Epoxycyclohexylmethyl 3,4-Epoxycyclohexanecarboxylate (Trade name: CEL2021P, manufactured by Daicel Corporation)]: 32.5 parts • Cationic polymerizable compound (3) [1,2-epoxy-4-(2-oxyranyl)cyclohexane adduct of 2,2-bis(hydroxymethyl)-1-butanol (trade name: EHPE3150, manufactured by Daicel Corporation)]: 7.5 parts • Photocationic polymerization initiator [CPI-100P (manufactured by Sunapro Co., Ltd., 50% by mass solution)]: 2.3 parts • Photosensitizer [9,10-dibutoxyanthracene]: 1.0 part The storage modulus G' of the adhesive layer at a temperature of 25°C was 3150 MPa.

[0207] [Preparation of the adhesive layer] A 5 μm thick (meth)acrylic adhesive layer was prepared as the adhesive layer using the following process. In a reaction vessel equipped with a stirrer, thermometer, reflux condenser, dropping device, and nitrogen inlet tube, 95.0 parts by mass of n-butyl acrylate, 4.0 parts by mass of acrylic acid, 1.0 part by mass of 2-hydroxyethyl acrylate, 200 parts by mass of ethyl acetate, and 0.08 parts by mass of 2,2'-azobisisobutyronitrile were charged, and the air in the reaction vessel was replaced with nitrogen gas. Under a nitrogen atmosphere, the reaction solution was heated to 60°C while stirring and reacted for 6 hours, after which it was cooled to room temperature. The weight-average molecular weight of a portion of the obtained solution was measured, confirming the formation of a (meth)acrylic acid ester polymer with a molecular weight of 1.8 million. 100 parts by mass (solid content equivalent; the same applies hereinafter) of the (meth)acrylic acid ester polymer obtained in the above process, 1.5 parts by mass of trimethylolpropane-modified tolylene diisocyanate (manufactured by Tosoh Corporation, trade name "Coronate® L") as an isocyanate-based crosslinking agent, 0.30 parts by mass of 3-glycidoxypropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., trade name "KBM403") as a silane coupling agent, 7.5 parts by mass of ethoxylated isocyanuric acid triacrylate (manufactured by Shin-Nakamura Chemical Industry Co., Ltd., product name "A-9300") as an ultraviolet-curable compound, and 0.5 parts by mass of 2-methyl-1-(4-methylthiophenyl)-2-morpholinopropan-1-one (manufactured by BASF, Irgacure® 907) as a photopolymerization initiator were mixed, thoroughly stirred, and diluted with ethyl acetate to obtain a composition for forming an adhesive layer. The adhesive layer-forming composition was applied to the release surface (release layer surface) of a separator (Lintec Corporation: SP-PLR382190) using an applicator so that the thickness after drying would be 5 μm. After drying at 100°C for 1 minute, another separator (Lintec Corporation: SP-PLR381031) was attached to the side of the adhesive layer-forming composition opposite to the side to which the separator was attached. After drying, ultraviolet light (irradiation intensity 500 mW / cm²) was applied to the adhesive layer-forming composition through the separator (SP-PLR38) using a belt conveyor-equipped ultraviolet irradiation device (Fusion UV Systems, using a D-bulb lamp). 2 , cumulative light intensity 500 mJ / cm 2 The material was irradiated with ) to obtain an adhesive layer with a double-sided separator. The storage modulus G' of the adhesive layer at a temperature of 25°C was 106 kPa.

[0208] [Preparation of compositions for photoalignment film formation] A photo-alignment film-forming composition was obtained by mixing 2 parts of a photo-aligning polymer with a number-average molecular weight of 28,000 represented by the following chemical formula with 98 parts of o-xylene, and stirring the resulting mixture at 80°C for 1 hour. [ka] [In the formula, Me represents a methyl group]

[0209] [First retardation plate] First retardation plate A A cycloolefin resin film with an HC layer (hardened resin layer) (thickness 3 μm) was prepared by forming an acrylic HC layer (hardened resin layer) (thickness 3 μm) on one side of a cycloolefin polymer (COP) film (ZD12, manufactured by Nippon Zeon Co., Ltd., thickness 22 μm). The layer structure of the first phase difference plate A is HC layer / COP film. The in-plane phase difference value of the first phase difference plate A was measured using "KOBRA-WR" manufactured by Oji Instruments Co., Ltd. The in-plane phase difference value Re1(450) at a wavelength of 450 nm is 105 nm. The in-plane phase difference value Re1(550) at a wavelength of 550 nm is 100 nm. The in-plane phase difference value Re1(650) at a wavelength of 650 nm was 96 nm. Calculating Re1(450) / Re1(550) yields 1.05, and calculating Re1(650) / Re1(550) yields 0.96, confirming that the COP film in the first phase difference plate A has positive wavelength dispersion. Furthermore, the HC layer in the first phase difference plate A does not exhibit a phase difference and therefore does not affect the in-plane phase difference value. The glass transition temperature of the COP film in the first phase difference plate A was 131°C, and its tensile modulus was 2200 MPa. Furthermore, the pencil hardness of the HC layer surface of the first phase difference plate A was 2B.

[0210] First retardation plate B A uniaxially stretched triacetylcellulose (TAC) film, as described in Japanese Patent Publication No. 2023-167428, was procured. This was used as the first phase difference plate B (stretched TAC film) with a thickness of 25 μm. The layer structure of the first phase difference plate B consists only of a single layer of stretched TAC. The in-plane phase difference value of the first phase difference plate was measured using "KOBRA-WR" manufactured by Oji Instruments Co., Ltd. The in-plane phase difference value Re1(450) at a wavelength of 450 nm is 103 nm. The in-plane phase difference value Re1(550) at a wavelength of 550 nm is 105 nm. The in-plane phase difference value Re1(650) at a wavelength of 650 nm was 107 nm. Calculating Re1(450) / Re1(550) yields 0.98, and calculating Re1(650) / Re1(550) yields 1.02, confirming that the stretched TAC monolayer, which is the first phase difference plate B, has inverse wavelength dispersion. The glass transition temperature of the stretched TAC monolayer, which is the first phase difference plate B, was 180°C, and its tensile modulus was 4000 MPa. Furthermore, the pencil hardness of the surface of the first phase difference plate B was 5B.

[0211] First retardation plate C A triacetylcellulose film with an acrylic HC layer (cured resin layer) (thickness 3 μm) was prepared on one side of the first phase difference plate B (first phase difference plate C). The layer structure of the first phase difference plate C is HC layer / stretched TAC film. The in-plane phase difference value of the first phase difference plate C was measured using "KOBRA-WR" manufactured by Oji Instruments Co., Ltd. The in-plane phase difference value Re1(450) at a wavelength of 450 nm is 103 nm. The in-plane phase difference value Re1(550) at a wavelength of 550 nm is 105 nm. The in-plane phase difference value Re1(650) at a wavelength of 650 nm was 107 nm. Calculating Re1(450) / Re1(550) yields 0.98, and calculating Re1(650) / Re1(550) yields 1.02, confirming that the stretched TAC film in the first phase difference plate C exhibits inverse wavelength dispersion. Furthermore, the HC layer in the first phase difference plate C does not exhibit a phase difference and therefore does not affect the in-plane phase difference value. The glass transition temperature of the stretched TAC film in the first phase difference plate C was 180°C, and its tensile modulus was 4000 MPa. Furthermore, the pencil hardness of the HC surface of the first phase difference plate C was H.

[0212] First retardation plate D A triacetylcellulose (TAC) film with an acrylic HC layer (cured resin layer) (3 μm thick) was formed on one side of a triacetylcellulose (TAC) film (25 μm thick) manufactured by Konica Minolta, Inc., to prepare an HC-layered triacetylcellulose film (HC-TAC film). In accordance with Example 1 of Japanese Patent Application Publication No. 2021-124641, a release-treated TAC film was coated with a phase difference film-forming composition (a composition containing a polymerizable liquid crystal compound) on the release-treated side and dried. A laminate of the TAC film and the phase difference film was then produced by polymerizing the polymerizable liquid crystal compound contained in the dried coating. After plasma treatment was applied to both the TAC surface of the HC-TAC film and the phase difference film surface of the laminate, they were bonded together via the adhesive layer prepared above to form a laminate. Subsequently, the TAC film on the phase difference film side was peeled off to obtain a first phase difference plate D. The layer structure of this first phase difference plate D is HC layer / TAC film / adhesive layer / phase difference film. The in-plane phase difference value of the first phase difference plate D was measured using "KOBRA-WR" manufactured by Oji Instruments Co., Ltd. The in-plane phase difference value Re1(450) at a wavelength of 450 nm is 125 nm. The in-plane phase difference value Re1(550) at a wavelength of 550 nm is 113 nm. The in-plane phase difference value Re1(650) at a wavelength of 650 nm was 108 nm. Calculating Re1(450) / Re1(550) yields 1.11, and calculating Re1(650) / Re1(550) yields 0.96, confirming that the phase difference film in the first phase difference plate D has positive wavelength dispersion. Furthermore, the HC layer, TAC film, and adhesive layer in the first phase difference plate D do not exhibit phase difference and therefore do not affect the in-plane phase difference value. The glass transition temperature of the TAC film in the first phase difference plate D was 180°C, and its tensile modulus was 4000 MPa. Furthermore, the pencil hardness of the HC surface of the first phase difference plate D was H.

[0213] First retardation plate E A triacetylcellulose (TAC) film with an acrylic HC layer (cured resin layer) (3 μm thick) was formed on one side of a triacetylcellulose (TAC) film (25 μm thick) manufactured by Konica Minolta, Inc., to prepare an HC-layered triacetylcellulose film (HC-TAC film). In accordance with Example 1 of Japanese Patent Application Publication No. 2021-124641, a phase difference film forming composition (a composition containing a polymerizable liquid crystal compound) was applied to the release-treated side of a TAC film that had been subjected to a release treatment and dried. A laminate of the TAC film and the phase difference film was then fabricated by polymerizing the polymerizable liquid crystal compound contained in the dried coating. After plasma treatment was applied to both the TAC surface of the HC-TAC film and the phase difference film surface of the laminate, the active energy ray curable composition (cationic polymerizable adhesive composition) was applied to the TAC surface of the HC-TAC film to an adhesive layer thickness of 2 μm, and the coated surface and the phase difference film surface of the laminate were bonded together. Subsequently, using a belt conveyor-equipped ultraviolet irradiation device (manufactured by Fusion UV Systems, using a D-bulb lamp), ultraviolet light (irradiation intensity 500 mW / cm²) is applied through the TAC film of the laminate. 2 , cumulative light intensity 500 mJ / cm 2 The first phase difference plate E was obtained by irradiating the laminate with ) and peeling off the TAC film. The layer structure of this first phase difference plate E is HC layer / TAC film / adhesive layer / phase difference film. The in-plane phase difference value of the first phase difference plate E was measured using "KOBRA-WR" manufactured by Oji Instruments Co., Ltd. The in-plane phase difference value Re1(450) at a wavelength of 450 nm is 125 nm. The in-plane phase difference value Re1(550) at a wavelength of 550 nm is 113 nm. The in-plane phase difference value Re1(650) at a wavelength of 650 nm was 108 nm. Calculating Re1(450) / Re1(550) yields 1.11, and calculating Re1(650) / Re1(550) yields 0.96, confirming that the phase difference film in the first phase difference plate E has positive wavelength dispersion. Furthermore, the HC layer, TAC film, and adhesive layer in the first phase difference plate E do not exhibit phase difference and therefore do not affect the in-plane phase difference value. The glass transition temperature of the TAC film in the first phase difference plate E was 180°C, and its tensile modulus was 4000 MPa. Furthermore, the pencil hardness of the HC surface of the first phase difference plate E was H.

[0214] First retardation plate F A triacetylcellulose (TAC) film (HC-TAC film) with an acrylic HC layer (cured resin layer) (20 cm × 30 cm × 3 μm thick) was prepared by forming an HC layer on one side of a Konica Minolta triacetylcellulose (TAC) film (thickness 25 μm). After plasma treatment of the TAC surface of this HC-TAC film, the following photo-aligning polymer composition (1) was applied. The resulting coated film was dried at 120°C for 2 minutes, and then cooled to room temperature to form a dry film. Furthermore, using a UV irradiation device, polarized ultraviolet light of 100 mJ (based on 313 nm) was continuously irradiated at a 45° angle to the longitudinal direction of the HC-TAC film to form a 100 nm photo-aligned film. On this, the following phase difference film forming composition (1) was applied using a bar coater. The resulting coated film was dried at 100°C for 1 minute, and then cooled to room temperature to obtain a dry film. Next, using a high-pressure mercury lamp, exposure at 1000 mJ / cm² was applied under a nitrogen atmosphere. 2 By continuously irradiating the dried film with ultraviolet light (based on 365 nm), a phase difference film was formed in which the polymerizable liquid crystal compound was cured in a state where it was oriented horizontally to the substrate surface, thereby obtaining the first phase difference plate F. The layer structure of this first phase difference plate F is HC layer / TAC film / alignment film / phase difference film.

[0215] Preparation of photo-oriented polymer composition (1) A photo-oriented material with the following structure (weight-average molecular weight: 50,000, m:n=50:50) was prepared according to the method described in Japanese Patent Application Publication No. 2021-196514. Two parts of the photo-oriented material and 98 parts of propylene glycol monomethyl ether (PGME, solvent) were mixed, and the resulting mixture was stirred at 80°C for 1 hour to prepare a photo-oriented polymer composition (1). Photoalignable materials: [ka]

[0216] Preparation of the phase difference film forming composition (1) The polymerizable liquid crystal compound Paliocolor® LC242 (manufactured by BASF Japan), whose structure is shown below, was mixed with the leveling agent "BYK-361N" (manufactured by BYK-Chemie), the photopolymerization initiator "Omnirad 907" (manufactured by IGM Resin BV), and the additive "Laromer® LR-9000" (manufactured by BASF Japan). Furthermore, propylene glycol 1-monomethyl ether 2-acetate (PGME) was added, and this mixture was stirred at 80°C for 1 hour to prepare a phase difference film forming composition (1). The amounts of each component added are shown in Table 1 below. [Table 1] Polymerizable liquid crystal compound Paliocolor® LC242: [ka]

[0217] The in-plane phase difference value of the first phase difference plate F was measured using "KOBRA-WR" manufactured by Oji Instruments Co., Ltd. The in-plane phase difference value Re1(450) at a wavelength of 450 nm is 102 nm. The in-plane phase difference value Re1(550) at a wavelength of 550 nm is 95 nm. The in-plane phase difference value Re1(650) at a wavelength of 650 nm was 93 nm. Calculating Re1(450) / Re1(550) yields 1.07, and calculating Re1(650) / Re1(550) yields 0.98, confirming that the phase difference film on the first phase difference plate F has positive wavelength dispersion. Furthermore, the HC layer, TAC film, and alignment film on the first phase difference plate F do not exhibit phase difference and therefore do not affect the in-plane phase difference value. The glass transition temperature of the TAC film in the first phase difference plate F was 180°C, and its tensile modulus was 4000 MPa. Furthermore, the pencil hardness of the HC surface of the first phase difference plate F was H.

[0218] [Linear polarizing plate] (Preparation of polymerizable liquid crystal composition for forming a linearly polarized film) A polymerizable liquid crystal composition was obtained by mixing the following components and stirring at 80°C for 1 hour. The polymerizable liquid crystal compounds (X1) and (X2) have the structures shown below. The dichroic dyes (DP1) to (DP3) are azo dyes described in the examples of Japanese Patent Application Publication No. 2013-101328 and have the structures shown below. Polymerizable liquid crystal compound (X1): 75 parts Polymerizable liquid crystal compound (X2): 25 parts Dichroic dye (DP1): 2.5 parts Dichroic pigment (DP2): 2.5 parts Dichroic pigment (DP3): 2.5 parts Polymerization initiator [2-dimethylamino-2-benzyl-1-(4-morpholinophenyl)butan-1-one (Irgacure® 369; manufactured by BASF Japan): 6 parts Leveling agent [polyacrylate compound (BYK-361N; manufactured by BYK-Chemie)]: 1.2 parts Solvent [o-xylene]: 250 parts

[0219] ·Polymerizable liquid crystal compound (X1): [ka] ·Polymerizable liquid crystal compound (X2): [ka]

[0220] ·Dichroic dye (DP1): [ka] • Dichroic pigment (DP2): [ka] • Dichroic pigment (DP3): [ka]

[0221] (Preparation of composition for HC layer formation) The following components were mixed and stirred at 50°C for 4 hours to obtain an HC layer forming composition. • Acrylate monomer represented by the following chemical formula: 70 parts [ka] • Urethane acrylate resin [EBECRYL4858 (manufactured by Daicel Ornex Co., Ltd.)]: 30 parts • Polymerization initiator [Omnirad907 (manufactured by IGM Resins BV)]: 3 parts • Solvent [methyl ethyl ketone]: 10 parts

[0222] (Preparation of composition for forming an overcoat layer (water-soluble polymer aqueous solution)) A water-soluble polymer consisting of the following structural units was obtained according to the following synthesis scheme. [ka]

[0223] In 400 g of dimethyl sulfoxide, 20 g of polyvinyl alcohol (manufactured by Wako Pure Chemical Industries, Ltd.) with a molecular weight of 1000, 0.55 mg of N,N-dimethyl-4-aminopyridine as a nucleophile, and 4.6 g of triethylamine were dissolved and the temperature was raised to 60°C while stirring. Then, a solution of 10.5 g of methacrylic anhydride dissolved in 50 g of dimethyl sulfoxide was added dropwise over 1 hour, and the reaction was carried out by heating and stirring at 60°C for 14 hours. After the resulting reaction solution was cooled to room temperature, 481 g of methanol was added to the reaction solution and stirred until completely mixed, adjusting the ratio (mass) of reaction solution to methanol to 1:1. By gradually adding 1500 mL of acetone to this solution, the water-soluble polymer was crystallized by crystallization. The solution containing the obtained white crystals was filtered, thoroughly washed with acetone, and then vacuum dried to obtain 20.2 g of water-soluble polymer. The obtained water-soluble polymer was dissolved in water to prepare a 3% by mass aqueous solution of the water-soluble polymer.

[0224] (Fabrication of linear polarizing plates) The HC layer-forming composition obtained above was continuously applied to the release surface of a roll-shaped release polyethylene terephthalate (PET) film with a film width of 800 mm (Unitika Ltd. "FF-50", single-sided release treated PET film (supporting substrate thickness: 50 μm)) using a slot die coater, and dried at a temperature of 100°C for 2 minutes to form an HC layer with a thickness of 2.00 μm. As a result, a film was obtained in which the HC layer was laminated on the release surface of the single-sided release treated PET film, and this was used as the first substrate layer.

[0225] After plasma treatment of the HC layer of the first substrate layer, the photo-alignment film-forming composition prepared above was applied using a slot die coater to form a coating layer in a 600 mm wide area in the center of the single-sided release-treated PET film. Next, the solvent was removed by transporting the film through a ventilated drying oven set at 100°C for 2 minutes, and the coating layer on the HC layer was dried. After drying, the coating layer was exposed to polarized UV light at a 90° angle to the length direction of the single-sided release-treated PET film at a rate of 20 mJ / cm². 2An orientation-regulating force was applied by irradiating the HC layer to an intensity of 313 nm (based on 313 nm), thereby forming a photo-alignment film on the HC layer. The thickness of the photo-alignment film was approximately 50 nm.

[0226] A polymerizable liquid crystal composition for forming the linearly polarized film prepared above was applied to the photo-alignment film formed on the first substrate layer using a slot die coater, forming a coated layer in a 600 mm wide area in the center of the first substrate layer. Next, the solvent was removed by transporting the material through a ventilated drying oven set at 110°C for 2 minutes, and the coated layer on the first substrate layer was dried. Then, ultraviolet light at 1000 mJ / cm² was applied using a high-pressure mercury lamp. 2 By irradiating at 365 nm (based on a standard wavelength) and curing the polymerizable liquid crystal compound contained in the above-mentioned coating layer after drying, a cured layer of polymerizable liquid crystal composition for forming a linearly polarized film was formed, and a liquid crystal polarized film with a substrate layer was obtained in which the photo-alignment film and the cured layer (together a liquid crystal polarized film) were formed in this order on the first substrate layer. The liquid crystal polarized film with a substrate layer had an absorption axis in the direction 90° with respect to the length direction. The thickness of the cured layer was 3 μm.

[0227] Next, the liquid crystal polarizing film side of the substrate layer-attached liquid crystal polarizing film was subjected to plasma treatment. Then, the aqueous solution of the water-soluble polymer prepared above was continuously applied using a slot die coater and dried at 100°C for 2 minutes to form an overcoat layer with a thickness of 2 μm. This resulted in obtaining a long linear polarizing plate with a substrate layer, comprising a first substrate layer (single-sided release-treated PET film / HC layer) / liquid crystal polarizing film (photo-alignment film / cured layer) / overcoat layer in this order. The single-sided release-treated PET film was peeled off from the obtained linear polarizing plate with a substrate layer and used as a linear polarizing plate.

[0228] Separately, a linear polarizing plate, before the single-sided release-treated PET film was peeled off, was cut into a 40mm x 40mm square. The overcoat layer side was bonded to an alkali-free glass plate (Corning, product name "Eagle-XG") using a 25μm thick acrylic adhesive (Lintec Corporation, product name "P-3132"), and then the single-sided release-treated PET film was peeled off to obtain a test specimen.

[0229] The single-element transmittance (T1) in the transmission axis direction (perpendicular to orientation) and the single-element transmittance (T2) in the absorption axis direction (orientation direction) of the obtained test specimens were measured using the double-beam method in 2 nm steps over a wavelength range of 380 to 680 nm with a spectrophotometer (Shimadzu Corporation UV-3150) equipped with a holder with a linear polarizer. The single-element transmittance and polarization degree at each wavelength were calculated using equations (15) and (16) below. Furthermore, luminous efficiency correction was performed using a 2-degree field of view (C light source) according to JIS Z 8701 to calculate the luminous efficiency-corrected single-element transmittance (Ty) and luminous efficiency-corrected polarization degree (Py). Single-element transmittance [%] = (T1 + T2) / 2 (15) Polarization degree [%] = [(T1-T2) / (T1+T2)] × 100 (16)

[0230] As a result, the luminous efficiency-corrected single-element transmittance (Ty) of the test specimen was 42%, and the luminous efficiency-corrected polarization degree (Py) was 97%, confirming that these are useful values ​​for a polarizer. Furthermore, when the luminous efficiency-corrected single-element transmittance (Ty) and luminous efficiency-corrected polarization degree (Py) were calculated using the above procedure after heating the test specimen at 100°C for 120 hours, the luminous efficiency-corrected single-element transmittance (Ty) was still 42% and the luminous efficiency-corrected polarization degree (Py) was 97% even after heating, and no decrease in optical performance was observed.

[0231] [Second retardation plate] (Preparation of a composition for forming a phase difference film) A composition for forming a phase difference film was obtained by mixing the following components and stirring at 80°C for 1 hour. ·Polymerizable liquid crystal: Compound (A11-1): 80 parts [ka] ·Polymerizable liquid crystal: Compound (x-1): 20 parts [ka] • Polymerization initiator: 2-dimethylamino-2-benzyl-1-(4-morpholinophenyl)butan-1-one (Irgacure® 369; manufactured by BASF Japan): 8 parts • Leveling agent: Polyacrylate compound (BYK-361N; manufactured by BYK-Chemie): 0.1 part Other additives: LALOMER LR9000 (BASF Japan): 6.7 parts • Solvent: Cyclopentanone: 546 parts • Solvent: N-methylpyrrolidone: 364 parts

[0232] (Fabrication of liquid crystal phase difference films) The photo-alignment film-forming composition prepared above was applied to the release-treated surface of a roll-shaped release polyethylene terephthalate (PET) film with a film width of 800 mm (Unitika Ltd. "FF-50", single-sided release-treated PET film, support substrate thickness: 50 μm) using a slot die coater, covering a 600 mm wide area in the center of the film. The resulting coating was dried at 120°C for 2 minutes, then cooled to room temperature to form a dry coating. Polarized ultraviolet light was then applied to the dry coating at a density of 100 mJ / cm² such that the direction of the orientation-regulating force was at a 0° angle with respect to the transport direction (long direction) of the long film. 2 A long photo-aligned film was formed by irradiation (based on 313 nm). The thickness of the photo-aligned film was 50 nm.

[0233] On this photo-alignment film, the above-mentioned phase difference film-forming composition was applied to a 600 mm wide area in the center of the film using a slot die coater to form a coating film. This coating film was heated and dried at 120°C for 2 minutes, then cooled to room temperature to form a dried coating film. The dried coating film was then exposed to ultraviolet light using an ultraviolet light irradiation device at an exposure dose of 1000 mJ / cm². 2 A liquid crystal phase difference film was formed by irradiation with ultraviolet light (based on 365 nm). The thickness of the liquid crystal phase difference film was 2.1 μm. This resulted in a long second phase difference plate with a release PET film, comprising a release PET film, a photoalignment film, and a liquid crystal phase difference film in that order. The release PET film was peeled off from the second phase difference plate with the release PET film attached, and the in-plane phase difference value of the second phase difference plate was measured using "KOBRA-WR" manufactured by Oji Instruments Co., Ltd. The in-plane phase difference value Re2(450) at a wavelength of 450 nm is 118 nm. The in-plane retardation value Re2(550) at a wavelength of 550 nm is 140 nm, The in-plane retardation value Re2(650) at a wavelength of 650 nm was 146 nm. Calculating Re2(450) / Re2(550) gives 0.84, and calculating Re2(650) / Re2(550) gives 1.04. From this, it was confirmed that the liquid crystal retardation film in the second retardation plate has inverse wavelength dispersion. Note that since the photo-alignment film in the second retardation plate does not exhibit retardation, it does not affect the in-plane retardation value.

[0234] [Fabrication of Optical Laminate A (Circular Polarizing Plate A)] The first retardation plate A, adhesive layer, linear polarizer, adhesive layer, and second retardation plate with a release PET film prepared above were laminated in order, and the release PET film was peeled off to obtain an optical laminate A. The first retardation plate was laminated such that the COP film side was laminated with the adhesive layer, the linear polarizer was laminated such that the HC layer was on the side of the first retardation plate A, and the second retardation plate was laminated such that the liquid crystal retardation film side was laminated with the adhesive layer. At that time, the slow axis of the first retardation plate A and the absorption axis of the linear polarizer formed an angle of 45°, and the absorption axis of the linear polarizer and the slow axis of the second retardation plate formed an angle of 45°. In the optical laminate A, the retardation value Re1(550) of the first retardation plate at a wavelength of 550 nm is 100 nm, and the retardation value Re2(550) of the second retardation plate at a wavelength of 550 nm is 140 nm. Therefore, the optical laminate A satisfies the following formula (1): Re1(550) < Re2(550) Formula (1) was confirmed.

[0235] [Fabrication of Optical Laminates B to F (Circular Polarizing Plates B to F)] Optical laminates B to F were fabricated in the same manner as optical laminate A, except that first retardation plates B to F were used instead of first retardation plate A. In the fabrication of optical laminate C, the stretched TAC side of the first retardation plate C was laminated with the adhesive layer, and in the fabrication of optical laminates D to F, the retardation film side of the first retardation plates D to F was laminated with the adhesive layer. In the optical laminate B and C, the retardation value Re1(550) of the first retardation plate at a wavelength of 550 nm is 105 nm, and the retardation value Re2(550) of the second retardation plate at a wavelength of 550 nm is 140 nm. In the optical laminates D and E, the retardation value Re1(550) of the first retardation plate at a wavelength of 550 nm is 113 nm, and the retardation value Re2(550) of the second retardation plate at a wavelength of 550 nm is 140 nm. In the optical laminate F, the retardation value Re1(550) of the first retardation plate at a wavelength of 550 nm is 95 nm, and the retardation value Re2(550) of the second retardation plate at a wavelength of 550 nm is 140 nm. Therefore, the optical laminates B to F satisfy the following formula (1): Re1(550) < Re2(550) Formula (1) It was confirmed that they satisfy this.

[0236] [Production of Optical Laminate G (Circular Polarizing Plate G)] Plasma treatment was performed on the retardation film surface of the first retardation plate E prepared above and the HC layer surface of the linear polarizing plate. The active energy ray-curable composition (cationic polymerizable adhesive composition) was applied to the retardation film surface of the first retardation plate E so that the thickness of the adhesive layer became 2 μm, and the applied surface and the HC layer surface of the linear polarizing plate were bonded together. The obtained laminate was irradiated with ultraviolet light having an exposure amount of 400 mJ / cm 2 (based on 365 nm) from the linear polarizing plate side, and a laminate composed of the first retardation plate E (HC layer / TAC film / adhesive layer / retardation film), the adhesive layer, and the linear polarizing plate (HC layer / liquid crystal polarizing film (photo-alignment film / hardened product layer) / overcoat layer) was obtained. An optical laminate G was obtained in the same manner as the optical laminate A, except that this laminate was used instead of the first retardation plate A, the adhesive layer, and the linear polarizing plate. The absorption axis of the linear polarizing plate and the slow axis of the second retardation plate were laminated so that they formed an angle of 45°, and the slow axis of the first retardation plate and the absorption axis of the linear polarizing plate formed an angle of 45°. In the optical laminate G, since the retardation value Re1(550) of the first retardation plate at a wavelength of 550 nm is 113 nm and the retardation value Re2(550) of the second retardation plate at a wavelength of 550 nm is 140 nm, the optical laminate A satisfies the following formula (1): Re1(550) < Re2(550), Formula (1) It was confirmed that this was satisfied.

[0237] [Production of Optical Laminate H (Circular Polarizing Plate H)] An optical laminate H was produced in the same manner as the optical laminate G, except that a first retardation plate F was used instead of the first retardation plate E. In the optical laminate H, the retardation value Re1(550) at a wavelength of 550 nm of the first retardation plate is 95 nm, and the retardation value Re2(550) at a wavelength of 550 nm of the second retardation plate is 140 nm. Therefore, the optical laminate A satisfies the following formula (1): Re1(550) < Re2(550), Formula (1) It was confirmed that this was satisfied.

[0238] [Evaluation of Optical Laminate (Circular Polarizing Plate)] [Performance of First Retardation Plate after High Temperature Exposure] The optical laminates A to H were each cut into 100 × 100 mm pieces and placed in a constant temperature bath at 120°C for 1 minute for heating. After taking them out from the constant temperature bath, the in-plane retardation values of the first retardation plates of the optical laminates A to H were measured using "KOBRA-WR" manufactured by Oji Scientific Instruments Co., Ltd., and compared with the in-plane retardation values in the raw material state used for the optical laminates A to H. At this time, those with a change rate of the retardation value at 550 nm of 0 to 5% were evaluated as "A", those with 5 to 15% as "B", those with 15 to 25% as "C", and those with 25% or more as "D".

[0239] [Evaluation of Crack Resistance] Optical laminates A through H were each cut to 70 x 90 mm. A 6 mm diameter through-hole was drilled in the center of each optical laminate using a UV laser (Keyence 3-Axis YVO4 laser marker "MD-V9900A"). Using an adhesive of the same shape as the optical laminate with the through-hole, the optical laminate with the through-hole was attached to an alkali-free glass plate (Corning, product name "Eagle-XG") to obtain samples for evaluating crack resistance. These samples were placed in an autoclave and subjected to a heat shock test by exposing them to -40°C for 30 minutes, followed by 85°C for 30 minutes. The optical laminates A to H were visually evaluated by microscopic observation after being exposed to -40°C for 30 minutes and 85°C for 30 minutes for 50 cycles. Those with no cracks at all in the through-holes were rated "A", those with cracks less than 50 μm were rated "B", those with cracks between 50 μm and 100 μm were rated "C", and those with cracks 100 μm or larger were rated "D". Furthermore, none of the samples showed any cracks before the heat shock test was conducted.

[0240] <Evaluation of reflectance> The second phase difference plate side of optical laminates A to H was bonded to an aluminum reflector via an adhesive layer, a cover glass was placed on the surface side via adhesive, and after autoclaving, the reflectance was measured using a Konica Minolta spectrophotometer CM-26d. The SCI value in the Y stimulation value was used as the reflectance. Reflectances of 5.0-5.2% were evaluated as "A", 5.2-5.3% as "B", and 5.3-5.5% as "C".

[0241] <Indentation test> Indentation tests were conducted to simulate foreign objects and external indentations during roll winding. Specifically, optical laminates A to H were first cut into 40 x 40 mm pieces. Then, indentation tests were performed on the surface of the first phase difference plate side of each optical laminate using an Erichsen pen. After indentation with an Erichsenpen, the condition of the indentation on the outermost surface was evaluated according to the following criteria. In the 1N Erichsenpen test, samples that showed no indentation immediately after the test were classified as "A," samples that showed an indentation immediately after the test but had largely recovered upon re-examination after 10 minutes were classified as "B," and samples that showed a persistent indentation that did not disappear after 10 minutes were classified as "C."

[0242] The results of the above evaluation items are summarized in the table below. [Table 2]

Claims

1. A circular polarizer comprising a first phase difference plate, a polarizing plate, and a second phase difference plate in this order, The first phase difference plate includes a thermoplastic resin layer having a glass transition temperature of 150°C or higher and a tensile modulus of 3500 MPa or higher. The polarizing plate includes a cured layer of a polymerizable liquid crystal composition containing a polymerizable liquid crystal compound and a dichroic dye. The second phase difference plate is a circular polarizing plate comprising a cured layer of a polymerizable liquid crystal composition containing a polymerizable liquid crystal compound.

2. The phase difference value Re of the first phase difference plate at a wavelength of 550 nm １ (550) and the phase difference value Re of the second phase difference plate at a wavelength of 550 nm ２ (550) is as follows: (1) Re １ (550) <Re ２ (550) Formula (1) A circular polarizer according to claim 1, satisfying the requirements.

3. The circular polarizer according to claim 1, wherein the thermoplastic resin layer exhibits reverse wavelength dispersion.

4. The circular polarizer according to claim 1, wherein the first phase difference plate includes the thermoplastic resin layer and the phase difference film, and the phase difference film exhibits positive wavelength dispersion.

5. The circular polarizer according to claim 1, wherein the cured layer contained in the second phase difference plate exhibits inverse wavelength dispersion.

6. The circular polarizer according to claim 1, further comprising a cured resin layer on the side of the first phase difference plate opposite to the polarizer side.

7. The circular polarizing plate according to claim 1, having a deformed portion within the plane of the circular polarizing plate.

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