Optical layered body, layered optical film, optical article, and virtual reality display device

Abstract

The present invention addresses the problem of providing an optical layered body that produces few ghosts when used in a virtual reality display device or the like, a layered optical film that comprises the optical layered body, an optical article that comprises the optical layered body, and a virtual reality display device that includes the optical article. An optical layered body according to the present invention has, in order, an adhesive layer, an optical interference layer, and two or more layered reflection layers. The layered reflection layers include one of each of a reflection layer A that includes at least one cholesteric liquid crystal layer that comprises rod-shaped crystals and a reflection layer B that includes at least one cholesteric liquid crystal layer that comprises disc-shaped crystals. When the reflection layers A or the reflection layers B are opposite each other at adjacent layered reflection layers, the reflection center wavelengths of adjacent reflection layers differ. When nA is the refractive index of the adhesive layer and nL is the average refractive index of the reflection layer adjacent to the optical interference layer, the refractive index nI of the optical interference layer satisfies (nA×nL)1 / 2-0.03≤nI≤(nA×nL)1 / 2+0.03. The film thickness of the optical interference layer is 60–110 nm or 230–330 nm.

Description

Optical laminate, laminated optical film, optical article and virtual reality display device

[0001] The present invention relates to an optical laminate, a laminated optical film, an optical article, and a virtual reality display device.

[0002] A reflective polarizer is a polarizer that reflects one polarized light and transmits the other polarized light. The reflected light and transmitted light by a reflective polarizer are polarized in mutually orthogonal directions. Here, the orthogonal polarization states refer to polarization states located at antipodes on the Poincaré sphere, such as mutually orthogonal linearly polarized light, and right-handed circularly polarized light and left-handed circularly polarized light.

[0003] Known examples of reflective linear polarizers that produce linearly polarized transmitted and reflected light include a film obtained by stretching a dielectric multilayer film as described in Patent Document 1 and a wire grid polarizer as described in Patent Document 2.

[0004] Furthermore, as a reflective circular polarizer in which transmitted light and reflected light become circularly polarized light, for example, a film having a light-reflecting layer in which a cholesteric liquid crystal phase is fixed, as described in Patent Document 3, is known.

[0005] Reflective polarizers are used to extract only specific polarized light from incident light or to split incident light into two polarized lights. For example, in liquid crystal display devices, they are used as brightness enhancement films that reflect and reuse unwanted polarized light from the backlight, thereby improving light utilization efficiency. They are also used as beam splitters in liquid crystal projectors that split light from a light source into two linearly polarized lights and supply each to a liquid crystal panel.

[0006] In recent years, methods have been proposed that use reflective polarizers to reflect a portion of external light and light from an image display device to generate a virtual or real image. For example, Patent Document 4 discloses an in-vehicle rearview mirror that uses a reflective polarizer to reflect light from behind. Furthermore, Patent Document 5 discloses a method for generating a virtual image by reflecting light back and forth between a reflective polarizer and a half mirror in order to make the display unit of a virtual reality display device, an electronic viewfinder, or the like smaller and thinner.

[0007] Japanese Patent Application Laid-Open No. 2011-053705 Japanese Patent Application Laid-Open No. 2015-028656 Japanese Patent No. 6277088 Japanese Patent Application Laid-Open No. 2017-227720 Japanese Patent Application Laid-Open No. 7-120679

[0008] The inventors' research has revealed that when a reflective polarizer reflects a portion of external light and light from an image display device to generate a virtual or real image, conventional reflective polarizers such as those described in Patent Documents 1 and 2 may result in reduced image sharpness. In contrast, the inventors have found that good image sharpness can be achieved by using a reflective circular polarizer having a light-reflecting layer with a fixed cholesteric liquid crystal phase. The inventors believe that this is because the light-reflecting layer with a fixed cholesteric liquid crystal phase enables a reflective circular polarizer with a high polarization degree to be realized as a thin film, making it less susceptible to the effects of foreign matter contamination and fluctuations due to the density of the material distribution. Furthermore, the inventors' research has revealed that virtual reality display devices and electronic viewfinders, etc., utilize both reflected and transmitted light. In these cases, it is important to suppress ghosting, which occurs when transmitted light that should be blocked is transmitted and becomes visible. The conventional reflective circular polarizer described in Patent Document 3 suppressed ghosting, leaving room for further improvement.

[0009] The present invention has been made in consideration of the above-mentioned problems, and the problem that the present invention aims to solve is to provide an optical laminate that can be used with a reflective circular polarizer that generates little ghosting when used in virtual reality display devices and electronic viewfinders, etc., a laminated optical film that includes the above-mentioned reflective circular polarizer, an optical article that includes the optical laminate, and a virtual reality display device that includes the optical article.

[0010] The present inventors have conducted extensive research into the above-mentioned problems and have found that the above-mentioned problems can be achieved by the following configuration.

[0011] [1] An optical laminate having an adhesive layer, a light interference layer, and two or more laminated reflective layers, wherein the laminated reflective layers include: a reflective layer A containing at least one cholesteric liquid crystal layer formed using a first liquid crystal compound substantially consisting of a rod-shaped liquid crystal compound, and not containing a cholesteric liquid crystal layer formed using a second liquid crystal compound substantially consisting of a discotic liquid crystal compound; and a reflective layer B containing at least one cholesteric liquid crystal layer formed using the second liquid crystal compound substantially consisting of a discotic liquid crystal compound, and not containing a cholesteric liquid crystal layer formed using the first liquid crystal compound substantially consisting of a rod-shaped liquid crystal compound, wherein when the reflective layers A in two of the two or more laminated reflective layers adjacent to each other in the stacking direction face each other, the central wavelengths of the reflected light of the reflective layers A included in the two adjacent laminated reflective layers are different from each other, When the reflective layers B of two or more laminated reflective layers adjacent in the lamination direction face each other, the central wavelengths of the reflected light of the reflective layers B included in the two adjacent laminated reflective layers are different, the adhesive layer, the optical interference layer, and the laminated reflective layer are adjacent in this order, and the refractive index of the adhesive layer is nA, and the average refractive index of the reflective layer A and the reflective layer B of the laminated reflective layer adjacent to the optical interference layer is nL, the refractive index nI of the optical interference layer is (nA×nL). １／２ −0.03≦nI≦(nA×nL) １／２+0.03, and the film thickness of the optical interference layer is 60 nm to 110 nm, or 230 nm to 330 nm. [2] The optical laminate according to [1], wherein the reflective layer A and the reflective layer B are alternately arranged in the stacking direction of the optical laminate. [3] The optical laminate according to [1], wherein the total number of layers in the stacked reflective layer is 20 or less. [4] The optical laminate according to [1], wherein the reflectance of light with a wavelength of 400 to 700 nm is 40% or more and less than 50%. [5] The optical laminate according to [1], wherein the stacked reflective layer is formed by one reflective layer A and one reflective layer B being in direct contact with each other, or is formed by one reflective layer A, one reflective layer B, and an adhesive layer arranged between the reflective layer A and the reflective layer B. [6] The optical laminate according to any one of [1] to [5], wherein the optical interference layer is a photo-alignment film. [7] The optical laminate according to any one of [1] to [5], wherein the light interference layer is a C plate. [8] The optical laminate according to [7], wherein a compound having a cinnamoyl group is present between the C plate and the laminated reflective layer. [9] The optical laminate according to any one of [1] to [5], wherein the light interference layer is a hard coat layer.

[10] A laminated optical film having, in this order, at least a reflective circular polarizer, a retardation layer that converts circularly polarized light into linearly polarized light, and a linear polarizer, wherein the reflective circular polarizer is the optical laminate according to any one of [1] to [9].

[11] The laminated optical film according to

[10] , wherein the linear polarizer comprises a light-absorbing anisotropic layer containing at least a liquid crystal compound and a dichroic material.

[12] The laminated optical film according to

[10] , further comprising a positive C plate.

[13] The laminated optical film according to

[10] , further comprising an antireflection layer on the surface.

[14] The laminated optical film according to

[13] , wherein the antireflection layer is a moth-eye film or an AR film.

[15] The laminated optical film according to

[10] , comprising a resin substrate having a peak temperature of loss tangent tanδ of 170° C. or less.

[16] An optical article comprising the optical laminate according to any one of [1] to [9].

[17] A virtual reality display device comprising the optical article according to

[16] .

[0012] According to the present invention, it is possible to provide an optical laminate that can be used for a reflective circular polarizer that generates little ghosting when used in a virtual reality display device, an electronic viewfinder, etc. Furthermore, according to the present invention, it is possible to provide a laminated optical film including the reflective circular polarizer, an optical article including the optical laminate, and a virtual reality display device including the optical article.

[0013] Fig. 1 is a schematic diagram showing an example of an optical laminate according to a first embodiment of the present invention. Fig. 2 is a schematic diagram showing an example of an optical laminate according to a first embodiment of the present invention. Fig. 3 is an example of a virtual reality display device using the laminated optical film of the present invention. Fig. 4 is an example of a virtual reality display device using the laminated optical film of the present invention. Fig. 5 is a schematic diagram showing an example of the laminated optical film of the present invention. Fig. 6 is a schematic diagram for explaining the function of the optical laminate of the present invention. Fig. 7 is a conceptual diagram for explaining the function of a conventional optical laminate.

[0014] The present invention will be described in detail below. The following description of the constituent elements may be based on representative embodiments and specific examples, but the present invention is not limited to such embodiments. In this specification, a numerical range expressed using "to" means a range that includes the numerical values ​​before and after "to" as the lower and upper limits.

[0015] In this specification, "orthogonal" does not mean an angle of exactly 90°, but means 90°±10°, preferably 90°±5°. "Parallel" does not mean an angle of exactly 0°, but means 0°±10°, preferably 0°±5°. "45°" does not mean an angle of exactly 45°, but means 45°±10°, preferably 45°±5°.

[0016] In this specification, "absorption axis" refers to the polarization direction in which absorbance is maximized in a plane when linearly polarized light is incident. "Reflection axis" refers to the polarization direction in which reflectance is maximized in a plane when linearly polarized light is incident. "Transmission axis" refers to the direction in a plane that is perpendicular to the absorption axis or reflection axis. "Slow axis" refers to the direction in a plane in which the refractive index is maximized. "Fast axis" refers to the direction in a plane in which the refractive index is minimized, and is the direction perpendicular to the slow axis.

[0017] In this specification, unless otherwise specified, phase difference refers to in-plane retardation, and is referred to as Re(λ). Here, Re(λ) represents the in-plane retardation at a wavelength λ, and unless otherwise specified, the wavelength λ is 550 nm. Furthermore, in this specification, the retardation in the thickness direction at a wavelength λ is referred to as Rth(λ). Unless otherwise specified, the wavelength λ is 550 nm. Re(λ) and Rth(λ) can be values ​​measured at a wavelength λ using an AxoScan OPMF-1 (manufactured by OptoScience). By inputting the average refractive index ((nx + ny + nz) / 3) and film thickness (d (μm)) into AxoScan, the slow axis direction (°) Re(λ) = R0(λ) and Rth(λ) = ((nx + ny) / 2 - nz) × d can be calculated.

[0018] The optical laminate of the present invention may be exemplified by the following first embodiment: Hereinafter, the first embodiment of the optical laminate of the present invention will be described.

[0019] [First embodiment] An optical laminate according to a first embodiment of the present invention has two or more laminated reflective layers, the laminated reflective layers each including a reflective layer A that includes at least one cholesteric liquid crystal layer (hereinafter also referred to as "liquid crystal layer 1") formed using a first liquid crystal compound substantially consisting of a rod-shaped liquid crystal compound and does not include a cholesteric liquid crystal layer (hereinafter also referred to as "liquid crystal layer 2") formed using a second liquid crystal compound substantially consisting of a discotic liquid crystal compound, and a reflective layer B that includes at least one liquid crystal layer 2 but does not include liquid crystal layer 1, when the reflective layers A face each other in two of the two or more laminated reflective layers adjacent to each other in the stacking direction, the central wavelengths of the reflected light of the reflective layers A included in the two adjacent laminated reflective layers are different, and when the reflective layers B face each other in two of the two or more laminated reflective layers adjacent to each other in the stacking direction, the central wavelengths of the reflected light of the reflective layers B included in the two adjacent laminated reflective layers are different, When the adhesive layer, the optical interference layer, and the laminated reflective layer are adjacent to each other in this order, and the refractive index of the adhesive layer is nA, and the average refractive index of the reflective layer A and the reflective layer B of the laminated reflective layer that is adjacent to the optical interference layer is nL, the refractive index nI of the optical interference layer is (nA×nL) １／２ −0.03≦nI≦(nA×nL) １／２ +0.03, and the film thickness of the optical interference layer is 60 nm to 110 nm, or 230 nm to 330 nm.

[0020] An optical laminate according to a first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a schematic cross-sectional view showing an example of the configuration of an optical laminate 10 according to the first embodiment. In the embodiment shown in FIG. 1, the optical laminate 10 is composed of a first laminated reflective layer 25, a second laminated reflective layer 26, an optical interference layer 27, and an adhesive layer 28. The first laminated reflective layer 25 is composed of a reflective layer A21a and a reflective layer B22b, and the second laminated reflective layer 26 is composed of a reflective layer A23a and a reflective layer B24b. In the optical laminate 10 according to the embodiment shown in FIG. 1, the reflective layer A21a, the reflective layer B22b, the reflective layer A23a, and the reflective layer B24b are laminated in this order. The optical laminate according to the first embodiment of the present invention can be used for a reflective circular polarizer. When the optical laminate has the above configuration, the reflective layer A has a positive Rth, while the reflective layer B has a negative Rth. Therefore, the Rths of the two layers are offset, and it is believed that the occurrence of ghosts can be suppressed even for light incident from an oblique direction. In addition, by setting the refractive index and film thickness of the optical interference layer to satisfy the above relationship, an anti-reflection effect can be imparted at the interface between the first laminated reflective layer and the adhesive layer. This means that changes in the rotation direction of circularly polarized light caused by interfacial reflection, such as the conversion of right-handed circularly polarized light to left-handed circularly polarized light due to interfacial reflection, can be suppressed. Since changes in the rotation direction of circularly polarized light caused by interfacial reflection are one of the causes of ghosts, it is believed that the occurrence of ghosts can be suppressed by suppressing interfacial reflection. This point will be described in detail later. Below, a first embodiment of the present invention will be described in detail.

[0021] [Laminated Reflective Layer] The optical laminate of the first embodiment of the present invention has two or more laminated reflective layers, each including one reflective layer A and one reflective layer B, which will be described in detail later. That is, the optical laminate of the first embodiment of the present invention includes two or more reflective layers A and two or more reflective layers B. In the laminated reflective layer, the reflective layer A and the reflective layer B may be in direct contact with each other, or the reflective layer A and the reflective layer B may be laminated via another layer. Examples of the other layer include, but are not limited to, an adhesion layer, a refractive index adjustment layer, a resin film, a positive C plate, and an alignment layer. Examples of the adhesion layer include an adhesive layer and a pressure-sensitive adhesive layer. The laminated reflective layer may be configured such that one reflective layer A and one reflective layer B are in direct contact with each other, or may be configured such that one reflective layer A, one reflective layer B, and an adhesion layer disposed between the reflective layer A and the reflective layer B are in direct contact with each other. In particular, the laminated reflective layer is preferably configured such that one reflective layer A and one reflective layer B are in direct contact with each other.

[0022] In the optical laminate, the laminated reflective layer may be laminated so that the reflective layers A and B are alternately arranged, or so that the reflective layers A face each other, or so that the reflective layers B face each other. For example, when the optical laminate of the first embodiment has two laminated reflective layers, they may be laminated in the order of reflective layer A, reflective layer B, reflective layer A and reflective layer B, or so that the reflective layers A, reflective layer B, reflective layer B and reflective layer A are laminated, or so that the reflective layers B, reflective layer A, reflective layer A and reflective layer B are laminated. However, when the reflective layers A face each other in the stacking direction in two adjacent laminated reflective layers, for example, when they are laminated in the order of reflective layer B, reflective layer A, reflective layer A and reflective layer B, the central wavelengths of the reflected light of the reflective layers A included in the two adjacent laminated reflective layers are different. Furthermore, when the reflective layers B of two adjacent laminated reflective layers in the stacking direction face each other, for example, when the layers are stacked in the order of reflective layer A, reflective layer B, reflective layer B, and reflective layer A, the central wavelengths of the reflected light of the reflective layers B included in the two adjacent laminated reflective layers are different.

[0023] Hereinafter, an optical laminate in which the reflective layers A of two adjacent laminated reflective layers in the stacking direction face each other will be described with reference to the drawings. The optical laminate 11 shown in FIG. 2 is composed of a first laminated reflective layer 25, a second laminated reflective layer 26, an optical interference layer 27, and an adhesive layer 28. The first laminated reflective layer 25 is composed of a reflective layer B21b and a reflective layer A22a, and the second laminated reflective layer 26 is composed of a reflective layer A23a and a reflective layer B24b. In the optical laminate 11 of the embodiment shown in FIG. 2, the reflective layer B21b, the reflective layer A22a, the reflective layer A23a, and the reflective layer B24b are stacked in this order. However, in this optical laminate 11, the center wavelength of the reflected light of the reflective layer A22a is different from the center wavelength of the reflected light of the reflective layer A23a. In addition, in the optical laminate 11 shown in FIG. 2 , the reflective layer A 22a is included in the first laminated reflective layer 25, and the reflective layer A 23a is included in the second laminated reflective layer 26. That is, as described in detail below, the reflective layer A may include two or more liquid crystal layers 1 having different central wavelengths of reflected light. However, when two or more liquid crystal layers 1 are arranged consecutively in the optical laminate, the reflective layer A and the laminated reflective layer are arranged so that the number of laminated reflective layers is maximized. Similarly, as described in detail below, the reflective layer B may include two or more liquid crystal layers 2 having different central wavelengths of reflected light. However, when two or more liquid crystal layers 2 are arranged consecutively in the optical laminate, the reflective layer B and the laminated reflective layer are arranged so that the number of laminated reflective layers is maximized. Among these, the laminated reflective layer is preferably arranged so that the reflective layer A and the reflective layer B are alternately arranged. That is, a preferred embodiment is one in which the reflective layer A and the reflective layer B are alternately arranged in the thickness direction of the optical laminate.

[0024] The optical laminate of the first embodiment includes two or more laminated reflective layers. Therefore, the optical laminate of the present invention may include three or four or more laminated reflective layers. That is, the optical laminate includes two or more layers of the reflective layer A and the reflective layer B, but may also include three or four or more layers of the reflective layer A and the reflective layer B. The total number of laminated reflective layers included in the optical laminate is preferably 30 or less, more preferably 20 or less, and even more preferably 10 or less. That is, the total number of the reflective layers A and the reflective layers B of the optical laminate is preferably 60 or less, more preferably 40 or less, and more preferably 20 or less.

[0025] The thickness of the laminated reflective layer is preferably 0.2 μm or more, more preferably 0.4 μm or more, and even more preferably 0.6 μm or more. The thickness of the laminated reflective layer is preferably 20.0 μm or less, more preferably 14.0 μm or less, and even more preferably 10.0 μm or less. The thickness of the laminated reflective layer can be measured in the same manner as for the reflective layer A and the reflective layer B described later.

[0026] The reflective layer A and the reflective layer B will be described below.

[0027] [Reflective Layer A] The laminated reflective layer included in the optical laminate of the first embodiment of the present invention includes a reflective layer A that includes at least one liquid crystal layer 1 but does not include a liquid crystal layer 2. The liquid crystal layer 1 is a cholesteric liquid crystal layer formed using a first liquid crystal compound that is substantially a rod-shaped liquid crystal compound, and is substantially composed of rod-shaped liquid crystal compounds. The "cholesteric liquid crystal layer formed using a first liquid crystal compound that is substantially a rod-shaped liquid crystal compound" refers to a layer in which the first liquid crystal compound is in a cholesteric liquid crystal phase and the orientation state of the cholesteric liquid crystal phase is fixed. The term "substantially composed of rod-shaped liquid crystal compounds" refers to a layer in which the rod-shaped liquid crystal compounds account for 95% by mass or more of the liquid crystal compounds (first liquid crystal compounds) contained in the liquid crystal layer 1. In other words, the term "first liquid crystal compound that is substantially composed of rod-shaped liquid crystal compounds" means that the content of the rod-shaped liquid crystal compounds is 95% by mass or more relative to the total mass of the first liquid crystal compounds. It is particularly preferable that the first liquid crystal compound is composed solely of rod-shaped liquid crystal compounds. Furthermore, the liquid crystal layer 2 is a cholesteric liquid crystal layer formed using a second liquid crystal compound substantially consisting of a discotic liquid crystal compound, and is substantially composed of a discotic liquid crystal compound. The term "cholesteric liquid crystal layer formed using a second liquid crystal compound substantially consisting of a discotic liquid crystal compound" refers to a layer formed by converting the second liquid crystal compound into a cholesteric liquid crystal phase and fixing the orientation state of the cholesteric liquid crystal phase. The term "substantially consisting of a discotic liquid crystal compound" refers to a layer in which the discotic liquid crystal compound accounts for 95% by mass or more of the liquid crystal compound (second liquid crystal compound) contained in the liquid crystal layer 2. In other words, the term "second liquid crystal compound substantially consisting of a discotic liquid crystal compound" means that the content of the discotic liquid crystal compound is 95% by mass or more of the total mass of the second liquid crystal compound. It is particularly preferable that the second liquid crystal compound consists solely of a discotic liquid crystal compound.

[0028] The reflective layer A may contain one or more liquid crystal layers 1, and therefore may contain two or more layers. When the reflective layer A contains two or more liquid crystal layers 1, layers other than the liquid crystal layer 2 may or may not be included between the two or more liquid crystal layers 1. Examples of such layers include, but are not limited to, an adhesion layer (e.g., an adhesive layer, a pressure-sensitive adhesive layer, etc.), a refractive index adjustment layer, a resin film, a positive C plate, and an alignment layer. The number of liquid crystal layers 1 contained in the reflective layer A is preferably five or less, more preferably three or less, and even more preferably two or less. The number of liquid crystal layers 1 contained in the reflective layer A is preferably one. For example, if two liquid crystal layers 1 have different central wavelengths of reflected light, they are considered to be two liquid crystal layers 1. Furthermore, if the central wavelengths of reflected light of two or more liquid crystal layers 1 are the same, they are considered to be one liquid crystal layer 1, even if they are formed by sequential coating or separated by the other layers.

[0029] When the reflective layer A includes two or more liquid crystal layers 1, the central wavelength of the reflected light of the reflective layer A is the central wavelength of the reflected light of the entire reflective layer A. The method for measuring the central wavelength of the reflected light is as described below.

[0030] The thickness of the reflective layer A is preferably 0.1 μm or more, more preferably 0.2 μm or more, and even more preferably 0.3 μm or more. The thickness of the reflective layer A is preferably 10.0 μm or less, more preferably 7.0 μm or less, and even more preferably 5.0 μm or less, in order to further suppress ghosting. The thickness of the reflective layer A can be measured by preparing a cross-section of the optical laminate and observing it with a scanning electron microscope. The thickness of the reflective layer A is a value obtained by averaging the thicknesses of the reflective layer A at any five points on the cross-section of the optical laminate. When the cross-section of the optical laminate is observed with a scanning electron microscope, the region of the reflective layer A and the region of the reflective layer B, which will be described later, can be distinguished by the difference in contrast of the captured image. In addition, the reflective layer A and the reflective layer B can also be distinguished by using composition analysis in the film thickness direction using time-of-flight secondary ion mass spectrometry (TOF-SIMS).

[0031] The Rth of the reflective layer A is preferably 8 to 800 nm, more preferably 16 to 560 nm, and even more preferably 24 to 400 nm at a wavelength of 550 nm. The Rth of the reflective layer A may be measured by taking out only the reflective layer A from the optical laminate, or may be measured by measuring the Rth of a layer prepared under the same conditions as when the reflective layer A is prepared.

[0032] Known rod-shaped liquid crystal compounds, preferably polymerizable rod-shaped liquid crystal compounds having a polymerizable group, can be used as the rod-shaped liquid crystal compound contained in the liquid crystal layer 1. Examples of the rod-shaped liquid crystal compound are not particularly limited, but include those described in claim 1 of JP-A-11-513019 or paragraphs

[0026] to

[0098] of JP-A-2005-289980.

[0033] It is also preferable to use a rod-shaped liquid crystal compound with a high refractive index anisotropy Δn (high Δn). Here, Δn is the difference between the refractive index in the slow axis direction and the refractive index in the fast axis direction. When a rod-shaped liquid crystal compound has high Δn characteristics, a high reflectance can be obtained even with a small number of turns in the helical structure of the cholesteric liquid crystal phase, thereby achieving the desired reflection characteristics even with a thin film thickness. By reducing the film thickness, the magnitude of the phase difference generated for incident light obliquely tilted from the normal direction of the cholesteric liquid crystal layer can be reduced, thereby further reducing ghosting. Liquid crystal compounds with a high refractive index anisotropy Δn are not particularly limited, but the compounds exemplified in paragraphs

[0014] to

[0029] of WO 2019 / 182129 and compounds represented by the following general formula (I) can be preferably used.

[0034]

[0035] In general formula (I), P １ and P ２ each independently represents a hydrogen atom, —CN, —NCS, or a polymerizable group. １ and Sp ２ each independently represents a single bond or a divalent linking group. １ and Sp ２does not represent a divalent linking group containing at least one group selected from the group consisting of an aromatic hydrocarbon ring group, an aromatic heterocyclic group, and an aliphatic hydrocarbon ring group. １ , Z ２ and Z ３ each independently represents a single bond, —O—, —S—, —CHR—, —CHRCHR—, —OCHR—, —CHRO—, —SO—, or —SO ２ -, -COO-, -OCO-, -CO-S-, -S-CO-, -O-CO-O-, -CO-NR-, -NR-CO-, -SCHR-, -CHRS-, -SO-CHR-, -CHR-SO-, -SO ２ -CHR-, -CHR-SO ２ -, -CF ２ O-, -OCF ２ -, -CF ２ S-, -SCF ２ -, -OCHRCHRO-, -SCHRCHRS-, -SO-CHRCHR-SO-, -SO ２ -CHRCHR-SO ２ -, -CH=CH-COO-, -CH=CH-OCO-, -COO-CH=CH-, -OCO-CH=CH-, -COO-CHRCHR-, -OCO-CHRCHR-, -CHRCHR-COO-, -CHRCHR-OCO-, -COO-CHR-, -OCO-CHR-, -CHR-COO-, -CHR-OCO-, -CR=CR-, -CR=N-, -N=CR-, -N=N-, -CR=N-N=CR-, -CF=CF- or C≡C-. R represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms. When multiple Rs are present, they may be the same or different. Z １ and Z ２ When there are a plurality of Z, they may be the same or different. ３ may be the same or different, provided that Sp ２ Z connected to ３ represents a single bond. １ and X ２ Each of X independently represents a single bond or S-. １ and X ２may be the same or different. １ and multiple Xs ２ At least one of them represents -S-. In general formula (I), k represents an integer of 2 to 4. In general formula (I), m and n each independently represent an integer of 0 to 3. Multiple m's may be the same or different. In general formula (I), A １ , A ２ , A ３ and A ４ each independently represents a group represented by any one of the following general formulae (B-1) to (B-7), or a group formed by linking two to three groups represented by any one of the following general formulae (B-1) to (B-7). ２ and A ３ may be the same or different. １ and A ４ When there are a plurality of each, they may be the same or different.

[0036]

[0037] In general formulas (B-1) to (B-7), W １ ~W １８ are each independently CR １ or N, R １ represents a hydrogen atom or the following substituent L. In general formulae (B-1) to (B-7), Y １ ~Y ６ are each independently NR ２ , O or S, R ２ represents a hydrogen atom or the following substituent L. In general formulae (B-1) to (B-7), G １ ~G ４ are each independently CR ３ R ４ , N.R. ５ , O or S, R ３ ~R ５ Each of the groups independently represents a hydrogen atom or the following substituent L. In general formulae (B-1) to (B-7), M １ and M ２ are each independently CR ６or N, R ６ represents a hydrogen atom or the following substituent L. * represents a bonding position.

[0038] The substituent L is an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, an alkylamino group having 1 to 10 carbon atoms, an alkylthio group having 1 to 10 carbon atoms, an alkanoyl group having 1 to 10 carbon atoms, an alkanoyloxy group having 1 to 10 carbon atoms, an alkanoylamino group having 1 to 10 carbon atoms, an alkanoylthio group having 1 to 10 carbon atoms, an alkyloxycarbonyl group having 2 to 10 carbon atoms, an alkylaminocarbonyl group having 2 to 10 carbon atoms, an alkylthiocarbonyl group having 2 to 10 carbon atoms, a hydroxy group, an amino group, a mercapto group, a carboxy group, a sulfo group, an amido group, a cyano group, a nitro group, a halogen atom, or a polymerizable group, provided that the above groups described as the substituent L are not —CH ２ When the group has -, -CH contained in the above group ２ Groups in which at least one of - is replaced by -O-, -CO-, -CH=CH- or C≡C- are also included in the substituent L. Furthermore, when the above groups described as the substituent L have a hydrogen atom, groups in which at least one of the hydrogen atoms contained in the above groups is replaced by at least one selected from the group consisting of a fluorine atom and a polymerizable group are also included in the substituent L.

[0039] In order to further reduce ghosting, the refractive index anisotropy Δn of the liquid crystal compound ５５０ (refractive index anisotropy at a wavelength of 550 nm) is preferably 0.12 or more, more preferably 0.16 or more, even more preferably 0.20 or more, and most preferably 0.25 or more. ５５０ The upper limit of the refractive index anisotropy at a wavelength of 550 nm is preferably 0.90 or less, more preferably 0.70 or less, and even more preferably 0.50 or less, from the viewpoint of suppressing interfacial reflection.

[0040] Furthermore, the liquid crystal layer 1 may be any layer in which the orientation of rod-shaped liquid crystal compounds in a cholesteric liquid crystal phase is maintained. Typically, the liquid crystal layer 1 can be formed by aligning a polymerizable rod-shaped liquid crystal compound having a polymerizable group in a cholesteric liquid crystal phase by adding a chiral agent or the like, and then polymerizing and curing the compound by ultraviolet irradiation, heating, or the like to form a layer with no fluidity. The liquid crystal layer 1 formed as described above may be any layer in which the orientation is not changed by an external field, external force, or the like. It is sufficient for the liquid crystal layer 1 to maintain the optical properties of the cholesteric liquid crystal phase, and the rod-shaped liquid crystal compound in the liquid crystal layer 1 may no longer exhibit liquid crystallinity. For example, the polymerizable rod-shaped liquid crystal compound may be polymerized by a curing reaction and no longer have liquid crystallinity.

[0041] The central wavelength λ of the reflected light of the liquid crystal layer 1 depends on the pitch P (= helical period) of the helical structure in the cholesteric liquid crystal phase, and is expressed by the relationship λ = n × P, where n is the average refractive index of the liquid crystal layer 1. The central wavelength of the reflected light of the liquid crystal layer 1 can be determined as follows. When the transmission spectrum of the reflective layer A is measured from the normal direction of the liquid crystal layer 1 using a spectrophotometer UV3150 (Shimadzu Corporation), a spectrum having a peak where the transmittance decreases in the region near the central wavelength of the reflected light is obtained. Of these, the value of the shorter wavelength of the two wavelengths at which the transmittance is half the value of the largest peak is determined as λ ｌ (nm), and the wavelength on the long wavelength side is λ ｈ (nm), the central wavelength λ of the reflected light is calculated by the following formula: λ = (λ ｌ +λ ｈ ) / 2

[0042] The pitch of the cholesteric liquid crystal phase varies depending on the type and concentration of the chiral agent used together with the polymerizable rod-like liquid crystal compound, and a cholesteric liquid crystal phase with a desired pitch can be obtained by adjusting one or more of the above. Regarding the method for measuring the helical direction and pitch, the methods described in "Introduction to Liquid Crystal Chemistry Experiments" edited by the Japanese Liquid Crystal Society, published by Sigma Publishing in 2007, page 46, and "Liquid Crystal Handbook" edited by the Liquid Crystal Handbook Editorial Committee, published by Maruzen, page 196, can be used.

[0043] [Reflective Layer B] The laminated reflective layer included in the optical laminate of the first embodiment of the present invention includes a reflective layer B that includes at least one liquid crystal layer 2 and does not include a liquid crystal layer 1. The definitions of the liquid crystal layer 2 and the liquid crystal layer 1 are as described above.

[0044] The reflective layer B may contain one or more liquid crystal layers 2, and therefore may contain two or more layers. When the reflective layer B contains two or more liquid crystal layers 2, layers other than the liquid crystal layer 1 may or may not be included between the two or more liquid crystal layers 2. Examples of such layers include, but are not limited to, an adhesion layer (e.g., an adhesive layer, a pressure-sensitive adhesive layer, etc.), a refractive index adjustment layer, a resin film, a positive C plate, and an alignment layer. The number of liquid crystal layers 2 contained in the reflective layer B is preferably five or fewer, more preferably three or fewer, and even more preferably two or fewer. The number of liquid crystal layers 2 contained in the reflective layer B is preferably one. For example, when two liquid crystal layers 2 have different central wavelengths of reflected light, they are considered to be two liquid crystal layers 2. Furthermore, when the central wavelengths of reflected light of two or more liquid crystal layers 2 are the same, they are considered to be one liquid crystal layer 2, even if they are formed by sequential coating or are separated by the other layers.

[0045] When the reflective layer B includes two or more liquid crystal layers 2, the central wavelength of the reflected light of the reflective layer B is the central wavelength of the reflected light of the entire reflective layer B. The central wavelength of the reflected light of each liquid crystal layer 2 is measured in accordance with the method for measuring the central wavelength of the reflected light of the liquid crystal layer 1 described above.

[0046] The thickness of the reflective layer B is preferably 0.1 μm or more, more preferably 0.2 μm or more, and even more preferably 0.3 μm or more. The thickness of the reflective layer B is preferably 10.0 μm or less, more preferably 7.0 μm or less, and even more preferably 5.0 μm or less, in order to further suppress ghosts. The thickness of the reflective layer B can be measured by preparing a cross section of the optical laminate and observing it with a transmission electron microscope.

[0047] The Rth of the reflective layer B is preferably −8 to −800 nm, more preferably −16 to −560 nm, and even more preferably −24 to −400 nm at a wavelength of 550 nm. The Rth of the reflective layer B may be measured by taking out only the reflective layer B from the optical laminate, or may be measured by measuring the Rth of a layer prepared under the same conditions as when the reflective layer B is prepared.

[0048] The discotic liquid crystal compound contained in the liquid crystal layer 2 is not particularly limited, and known discotic liquid crystal compounds can be used. As an example, the discotic liquid crystal compounds described in paragraphs

[0020] to

[0122] of JP 2007-108732 A can be suitably used. It is also preferable to use a liquid crystal compound with a high refractive index anisotropy Δn (high Δn). Here, Δn is the difference between the refractive index in the slow axis direction and the refractive index in the fast axis direction. When a discotic liquid crystal compound has high Δn characteristics, high reflectance can be obtained even with a small number of turns in the helical structure of the cholesteric liquid crystal phase, thereby achieving desired reflection characteristics even with a thin film thickness. Thinning the film can reduce the magnitude of the phase difference occurring with incident light obliquely tilted from the normal direction of the cholesteric liquid crystal layer, thereby further reducing ghosting. As the discotic compound having a high Δn, for example, the discotic liquid crystal compounds described in paragraphs

[0012] to

[0108] of JP-A-2010-244038 can be suitably used. ５５０ The refractive index anisotropy at a wavelength of 550 nm is preferably 0.12 or more, more preferably 0.16 or more, even more preferably 0.20 or more, and most preferably 0.25 or more. ５５０The upper limit of the refractive index anisotropy (at a wavelength of 550 nm) is preferably 0.90 or less, more preferably 0.70 or less, and even more preferably 0.50 or less, from the viewpoint of suppressing interfacial reflection. Furthermore, the liquid crystal layer 2 may be any layer in which the alignment of a discotic liquid crystal compound in a cholesteric liquid crystal phase is maintained. Typically, the liquid crystal layer 2 can be formed by aligning a polymerizable discotic liquid crystal compound having a polymerizable group in a cholesteric liquid crystal phase by adding a chiral agent or the like, and then polymerizing and curing the compound by ultraviolet irradiation, heating, or the like to form a non-fluid layer. The liquid crystal layer 2 formed as described above may be any layer in which the alignment state is not changed by external fields, external forces, or the like. It is sufficient for the liquid crystal layer 2 to maintain the optical properties of the cholesteric liquid crystal phase; the discotic liquid crystal compound in the liquid crystal layer 2 may no longer exhibit liquid crystallinity. For example, the polymerizable discotic liquid crystal compound may be polymerized by a curing reaction and no longer exhibit liquid crystallinity.

[0049] The central wavelength λ of the reflected light from the liquid crystal layer 2 depends on the pitch of the helical structure in the cholesteric liquid crystal phase, and can be defined in the same way as in the case of the liquid crystal layer 1 and can be measured in the same way.

[0050] The pitch of the cholesteric liquid crystal phase varies depending on the type and concentration of the chiral agent used together with the polymerizable discotic liquid crystal compound, and a cholesteric liquid crystal phase with a desired pitch can be obtained by adjusting one or more of the above. Note that the above-mentioned literature can be used as a reference for the method of measuring the helical direction and pitch.

[0051] The pitch of the cholesteric liquid crystal phase may also vary in the film thickness direction. The state in which the pitch varies in the film thickness direction is called a pitch gradient, and a layer in which the pitch varies in the film thickness direction is called a pitch gradient layer. The pitch gradient layer can be produced by a known method, for example, by referring to JP 2020-060627 A. In the pitch gradient layer, the helical pitch varies in the film thickness direction, and therefore light in multiple wavelength ranges can be reflected.

[0052] [Reflectance] The reflectance of the optical laminate of the first embodiment of the present invention for light with a wavelength of 400 to 700 nm is preferably 40% or more but less than 50%. When the reflectance is 40% or more, ghosting is more easily suppressed. The light with a wavelength of 400 to 700 nm refers to unpolarized light. The reflectance of the optical laminate for light with a wavelength of 400 to 700 nm is measured under the following conditions. An automatic absolute reflectance measurement system consisting of a V-750 ultraviolet-visible-near-infrared spectrophotometer manufactured by JASCO Corporation is used for the measurement. Polarized S-wave and P-wave light with wavelengths of 350 to 900 nm is incident on the optical laminate at an incident angle of 5°. The absolute reflectance for each of the S-wave and P-wave is measured, and the average value is calculated for each wavelength to obtain a reflectance spectrum. From the obtained reflectance spectrum, the average reflectance for light with a wavelength of 400 to 700 nm is calculated, and this is defined as the reflectance of the optical laminate for light with a wavelength of 400 to 700 nm.

[0053] [Types and Arrangements of Reflective Layer A and Reflective Layer B] The optical laminate of the first embodiment of the present invention includes the reflective layer A and the reflective layer B. Here, the optical laminate preferably includes at least a blue light reflective layer having a reflectance of 40% or more at a wavelength of 460 nm, a green light reflective layer having a reflectance of 40% or more at a wavelength of 550 nm, a yellow light reflective layer having a reflectance of 40% or more at a wavelength of 600 nm, and a red light reflective layer having a reflectance of 40% or more at a wavelength of 650 nm. The blue light reflective layer, green light reflective layer, yellow light reflective layer, and red light reflective layer may correspond to either the reflective layer A or the reflective layer B, respectively. For example, when the reflective layer A corresponds to the blue light reflective layer, the central wavelength of the reflected light of the reflective layer A may be adjusted by the above-mentioned method to set the central wavelength of the reflected light to about 460 nm. When the reflective layer B corresponds to the blue light reflective layer, the central wavelength of the reflected light of the reflective layer B may be adjusted by the above-mentioned method to set the central wavelength of the reflected light to about 460 nm. The reflectances are those when non-polarized light is incident on the reflective layer at each wavelength. When the optical laminate includes the blue light reflective layer, the green light reflective layer, the yellow light reflective layer, and the red light reflective layer, the optical laminate may have two or more blue light reflective layers, two or more green light reflective layers, two or more yellow light reflective layers, or two or more red light reflective layers.

[0054] The central wavelength of the reflected light of the blue light reflecting layer is preferably in the range of 430 nm or more and less than 500 nm. The central wavelength of the reflected light of the green light reflecting layer is preferably in the range of 500 nm or more and less than 570 nm. The central wavelength of the reflected light of the yellow light reflecting layer is preferably in the range of 570 nm or more and less than 620 nm. The central wavelength of the reflected light of the red light reflecting layer is preferably in the range of 620 nm or more and less than 670 nm. The method for measuring the central wavelength of the reflected light is as described above.

[0055] In addition, in the optical laminate of the first embodiment of the present invention, the central wavelengths of the reflected light of the reflective layer A and the reflective layer B included in the optical laminate may be adjusted so that the reflectance is 40% or more over the entire visible light region (wavelength 400 to 700 nm).

[0056] In addition, it is also preferable that the optical laminate has the above-mentioned blue light reflective layer, green light reflective layer, yellow light reflective layer, and red light reflective layer laminated in this order. Furthermore, when the optical laminate having the above-mentioned laminated order is applied to a reflective circular polarizer described later, the reflective layer on the long wavelength side (for example, red light reflective layer) needs a thicker reflective layer to obtain sufficient reflectivity, and the Rth of the reflective layer itself has a greater effect on the light transmitted through the reflective layer, so it is preferable that the reflective layer arranged on the light source side is a short wavelength reflective layer (for example, blue light reflective layer).

[0057] In the optical laminate of the first embodiment of the present invention, the reflective layer A has a positive Rth, whereas the reflective layer B has a negative Rth, so that the Rths of the two layers are offset. Details will be described below. In an optical laminate having n reflective layers, the reflective layers are arranged in order from the light source side as L １ , L ２ , L ３ , ..., L ｎ (n is an integer of 4 or more), the reflective layer L １ to the reflective layer L ｉ The sum of Rth of each layer up to (i is an integer equal to or less than n) is SRth ｉ Specifically, SRth ｉis expressed as follows: SRth １ = Rth １ SRth ２ = Rth １ +Rth ２ ... SRth ｉ = Rth １ +Rth ２ +...+Rth ｉ ... SRth ｎ = Rth １ +Rth ２ +...+Rth ｉ +...+Rth ｎ All these SRth ｉ (SRth １ ~SRth ｎ The absolute values ​​of Rth of each layer in the above formula are preferably 0.3 μm or less, more preferably 0.2 μm or less, and even more preferably 0.1 μm or less. ｉ is calculated by the above-described formula for calculating Rth. ｉ By setting the value of the reflection coefficient to be in the above-mentioned preferable range, it is considered that the phase difference occurring when transmitting through each reflective layer can be reduced, and the occurrence of ghosts can be further suppressed even for light incident from an oblique direction.

[0058] Furthermore, in the laminated reflective layer, when the reflective layer A and the reflective layer B are configured to be in direct contact with each other, it is preferable to arrange them so that the alignment direction (slow axis direction) of the liquid crystal compound (rod-shaped liquid crystal compound or discotic liquid crystal compound) changes continuously at the interface in order to reduce the difference in refractive index. For example, when the reflective layer A is formed on the reflective layer B, the above-mentioned arrangement can be achieved by directly applying a coating liquid containing a rod-shaped liquid crystal compound onto the reflective layer B, and aligning the slow axis direction so that it is continuous at the interface due to the alignment control force of the discotic liquid crystal compound contained in the reflective layer B.

[0059] The thickness of the optical laminate of the first embodiment of the present invention is preferably 30 μm or less, more preferably 15 μm or less. There is no particular lower limit, but for example, it can be 1 μm or more, and preferably 5 μm or more.

[0060] The method for producing the optical laminate of the first embodiment of the present invention, and a laminated optical film using the optical laminate will be described later.

[0061] [Light interference layer] The optical laminate of the present invention includes a light interference layer. The refractive index of the light interference layer satisfies the following condition. That is, when the refractive index of the adhesive layer adjacent to the light interference layer is nA, and the average refractive index of the reflective layer A or reflective layer B of the laminated reflective layer that is adjacent to the light interference layer is nL, the refractive index nI of the light interference layer is (nA x nL). １／２ −0.03≦nI≦(nA×nL) １／２ +0.03. In the optical laminate 10 shown in Figure 1, the refractive index nA of the adhesive layer 28, the average refractive index nL of the reflective layer A 21a, and the refractive index nI of the light interference layer 27 satisfy the above relationship. The refractive index nA of the adhesive layer adjacent to the light interference layer, the average refractive index nL of the reflective layer A or reflective layer B of the laminated reflective layer that is adjacent to the light interference layer, and the refractive index nI of the light interference layer are given by (nA x nL). １／２ −0.02≦nI≦(nA×nL) １／２ It is preferable to satisfy +0.02 (nA × nL) １／２ −0.01≦nI≦(nA×nL) １／２ It is more preferable that the relationship be +0.01. In the laminated reflective layer, either the reflective layer A or the reflective layer B may be adjacent to the optical interference layer. "The average refractive index of the reflective layer A or the reflective layer B of the laminated reflective layer that is adjacent to the optical interference layer is nL" means that when the reflective layer A is adjacent to the optical interference layer, the average refractive index of the reflective layer A is nL, and when the reflective layer B is adjacent to the optical interference layer, the average refractive index of the reflective layer B is nL.

[0062] By setting the refractive index of the light interference layer within this range, the amplitude reflectance on both sides of the light interference layer can be made approximately the same. Therefore, it is believed that a significant anti-reflection effect can be obtained. That is, if an optical laminate does not have a light interference layer, the reflective layer and adhesive layer of the laminated reflective layer are adjacent. In the optical laminate 10 shown in FIG. 1, the reflective layer A21a and adhesive layer 28 are adjacent. At the interface between the two layers, reflection occurs according to the difference in refractive index. For example, if the cholesteric liquid crystal layer (reflective layer) of the laminated reflective layer reflects right-handed circularly polarized light, if left-handed circularly polarized light unnecessarily passes through the laminated reflective layer, this light becomes a ghost. Specifically, when right-handed circularly polarized light enters from the adhesive layer side, the reflective layer constituting the laminated reflective layer reflects the right-handed circularly polarized light toward the adhesive layer side. In this case, a portion of the right-handed circularly polarized light reflected by the reflective layer (cholesteric liquid crystal layer) is reflected at the interface between the reflective layer and adhesive layer of the laminated reflective layer. During this reflection, the right-handed circularly polarized light is converted into left-handed circularly polarized light. As described above, the reflective layer (cholesteric liquid crystal layer) of the laminated reflective layer reflects right-handed circularly polarized light, while transmitting left-handed circularly polarized light. This unwanted left-handed circularly polarized light becomes ghosts. In contrast, the optical laminate of the present invention has an optical interference layer having the above-mentioned refractive index between the laminated reflective layer and the adhesive layer. By having such an optical interference layer, the optical laminate of the present invention can reduce the difference in refractive index at the interface between the laminated reflective layer and the adhesive layer. Specifically, by having such an optical interference layer, the optical laminate of the present invention can reduce the difference in refractive index between the reflective layer adjacent to the optical interference layer and the optical interference layer, and the difference in refractive index between the optical interference layer and the adhesive layer. This reduces interfacial reflection at the interface between the reflective layer and the adhesive layer, thereby suppressing changes in the rotation direction of circularly polarized light caused by interfacial reflection, such as the conversion of right-handed circularly polarized light to left-handed circularly polarized light due to interfacial reflection. Since changes in the rotation direction of circularly polarized light caused by interfacial reflection are one of the causes of ghosts, it is believed that suppressing interfacial reflection can suppress the occurrence of ghosts. The above points will be described in detail later using a virtual reality display device as an example.

[0063] The refractive indexes of the optical interference layer, the reflective layer, and the adhesive layer can be measured with reference to the methods described in the Examples. In the present invention, the refractive indexes of the layers are all measured for light with a wavelength of 550 nm.

[0064] In the optical laminate of the present invention, the film thickness of the optical interference layer is in the range of 60 to 110 nm or 230 to 330 nm. As described above, in the optical laminate of the present invention, the difference in refractive index between the reflective layer adjacent to the optical interference layer of the laminated reflective layer and the optical interference layer, and the difference in refractive index between the optical interference layer and the adhesive layer are small, thereby reducing reflection at this interface. However, some interfacial reflection still occurs between the two interfaces. In contrast, by setting the film thickness of the optical interference layer in the above range, the optical laminate of the present invention can suitably shift the phase of reflected light at both interfaces, allowing the reflected light at both interfaces to cancel each other out. As a result, ghosts caused by unwanted light reflection at the interfaces can be further reduced. These points will also be described in detail later using a virtual reality image display device as an example. The film thickness of the optical interference layer is preferably in the range of 75 to 100 nm or 245 to 300 nm, and more preferably in the range of 80 to 95 nm or 260 to 285 nm.

[0065] There are no limitations on the material for forming the optical interference layer, and the material is selected from the group consisting of (nA x nL) １／２ −0.03≦nI≦(nA×nL) １／２Various known materials can be used as long as they can provide a refractive index nI that satisfies the above formula (+0.03). Specifically, materials that can be used to form the optical interference layer include a hard coat material crosslinked from a monomer, a photo-alignment film, and a C-plate made of a liquid crystal material. Among these, the C-plate is more preferred because it can also function as an optical compensation adjustment. A positive C-plate is even more preferred. Here, a positive C-plate is a retardation layer having an Re of substantially zero and a negative Rth. A positive C-plate can be obtained, for example, by vertically aligning a rod-shaped liquid crystal compound. Details of the manufacturing method of a positive C-plate can be found in, for example, JP 2017-187732 A, JP 2016-053709 A, and JP 2015-200861 A. The positive C-plate functions as an optical compensation layer to increase the degree of polarization of transmitted light for obliquely incident light. The positive C-plate can be installed at any location on the laminated optical film, and multiple positive C-plates may be installed. In this case, the Re(550) of the C plate is preferably about 10 nm or less, and the Rth(550) is preferably −100 to −1 nm, more preferably −30 to −5 nm.

[0066] [Material for Interlayer Photo-Alignment Film] In the present invention, it is preferable that a material for an interlayer photo-alignment film is present between the optical interference layer and the laminated reflective layer. The material for the interlayer photo-alignment film may be contained in the optical interference layer. This allows the liquid crystal compound to be aligned when a liquid crystal material is applied to the optical interference layer, thereby forming a structure in which the optical interference layer and the reflective layer are adjacent to each other. As an example of a material for the interlayer photo-alignment film, the photo-alignable polymer described in JP-A-2021-143336 can be used. The material for the interlayer photo-alignment film is preferably a compound having a cinnamoyl group. In particular, when the optical interference layer is a C-plate, it is preferable that a compound having a cinnamoyl group, i.e., a cinnamoyl compound, is present between the optical interference layer and the laminated reflective layer. In other words, it is preferable that the cinnamoyl compound is present in the region near the boundary between the optical interference layer (preferably a C-plate) and the laminated reflective layer.

[0067] [Hard Coat Layer] The hard coat layer is not particularly limited as long as it satisfies the above-mentioned requirements for nI, and any known hard coat layer can be used. Examples of a method for forming the hard coat layer include a method in which a curable composition containing a crosslinkable monomer is applied onto the outermost cholesteric liquid crystal layer to form a coating layer, and the formed coating layer is cured to form the hard coat layer.

[0068] The crosslinkable monomer contained in the curable composition may be a monomer having a crosslinkable group. The crosslinkable group is not particularly limited, but may include a radically polymerizable group and a cationically polymerizable group. The radically polymerizable group is not particularly limited, but may include, for example, a vinyl group, a butadiene group, a (meth)acryloyl group, a (meth)acrylamide group, a vinyl acetate group, a fumarate ester group, a styryl group, a vinylpyrrolidone group, and a maleimide group, with a (meth)acrylic group being preferred. The term "(meth)acryloyl group" refers to a concept that includes an acryloyl group and a methacryloyl group. The cationically polymerizable group is not particularly limited, but may include, for example, a vinyl ether group, an epoxy group, and an oxetanyl group.

[0069] The monomer having a crosslinkable group may be used alone or in combination of two or more kinds.

[0070] The curable composition may also contain a polymerization initiator, and known polymerization initiators such as photopolymerization initiators and thermal polymerization initiators can be used as the polymerization initiator.

[0071] The refractive index of the hard coat layer can be adjusted, for example, by the refractive index of the crosslinkable monomer contained in the curable composition. For example, the refractive index of the hard coat layer can be increased by using a crosslinkable monomer having an aromatic ring or the like in the molecule as the crosslinkable monomer. On the other hand, the refractive index of the hard coat layer can be decreased by using a crosslinkable monomer not having an aromatic ring or the like in the molecule as the crosslinkable monomer. In addition, the refractive index of the hard coat layer can be adjusted by mixing inorganic oxide fine particles into the curable composition.

[0072] [Photo-Alignment Film] A preferred embodiment of the optical interference layer is a so-called photo-alignment film (photo-alignment layer) formed by irradiating a photo-alignable material with polarized or non-polarized light to form an alignment layer. It is preferable to impart an alignment control force to the photo-alignment film by irradiating it with polarized light from a vertical or oblique direction, or by irradiating it with non-polarized light from an oblique direction. By using a photo-alignment film, it is possible to horizontally align specific liquid crystal compounds with excellent symmetry. Therefore, a retardation layer positive A plate formed using a photo-alignment film is useful for optical compensation in liquid crystal displays that do not require a pre-tilt angle of the driving liquid crystal, such as IPS (In-Place-Switching) mode liquid crystal displays. Examples of photo-alignment materials used in the photo-alignment film include those disclosed in JP-A-2006-285197, JP-A-2007-076839, JP-A-2007-138138, JP-A-2007-094071, JP-A-2007-121721, JP-A-2007-140465, JP-A-2007-156439, and JP-A-2007- azo compounds described in JP-A-133184, JP-A-2009-109831, JP-A-3883848 and JP-A-4151746, aromatic ester compounds described in JP-A-2002-229039, maleimides having photo-orientable units described in JP-A-2002-265541 and JP-A-2002-317013 and / or alkenyl-substituted nadimide compounds, photocrosslinkable silane derivatives described in Japanese Patent Nos. 4205195 and 4205198, photocrosslinkable polyimides, polyamides or esters described in JP-T-2003-520878, JP-T-2004-529220 and JP-T-4162850, and photodimerizable compounds described in JP-A-9-118717, JP-A-10-506420, JP-A-2003-505561, WO 2010 / 150748, JP-A-2013-177561 and JP-A-2014-012823, in particular cinnamate compounds, chalcone compounds and coumarin compounds. Particularly preferred examples include azo compounds, photocrosslinkable polyimides, polyamides, esters, cinnamate compounds, and chalcone compounds.

[0073] [Adhesive Layer] The optical laminate of the present invention includes an adhesive layer. This adhesive layer is used to attach the optical laminate of the present invention to some optical member (optical component). For example, when the optical laminate of the present invention is used as a reflective circular polarizer in a virtual reality display device described below, the optical laminate of the present invention is attached to the lens of the optical system (pancake lens) constituting the virtual reality display device via the adhesive layer. As the adhesive layer, any known adhesive or pressure-sensitive adhesive can be used as appropriate, as long as it has a refractive index that satisfies the above-mentioned relationship. As an example, the adhesive and pressure-sensitive adhesive used in the laminated optical film described below can be used as appropriate. There are no limitations on the thickness of the adhesive layer, and it is sufficient to set the thickness that provides the required adhesive strength depending on the material forming the adhesive layer.

[0074] [Method for Producing Optical Laminate] The optical laminate of the present invention (first embodiment) can be produced by a known method, and the method is not particularly limited.

[0075] For example, the manufacturing method of the first embodiment may include the following steps: applying a composition containing a rod-shaped liquid crystal compound onto a substrate to form a cholesteric liquid crystal phase, then fixing the alignment state of the cholesteric liquid crystal phase to form a first cholesteric liquid crystal layer; applying a composition containing a discotic liquid crystal compound onto the first cholesteric liquid crystal layer to form a cholesteric liquid crystal phase, then fixing the alignment state of the cholesteric liquid crystal phase to form a second cholesteric liquid crystal layer; forming a third cholesteric liquid crystal layer on the second cholesteric liquid crystal layer in the same manner as the first cholesteric liquid crystal layer; and forming a fourth cholesteric liquid crystal layer on the third cholesteric liquid crystal layer in the same manner as the second cholesteric liquid crystal layer. Note that the first cholesteric liquid crystal layer and the third cholesteric liquid crystal layer correspond to the reflective layer A of the first embodiment, and the second cholesteric liquid crystal layer and the fourth cholesteric liquid crystal layer correspond to the reflective layer B of the first embodiment.

[0076] After the laminated reflective layer is formed in this manner, a light interference layer is formed on the surface of the laminated reflective layer. There are no limitations on the method for forming the light interference layer, and it may be appropriately selected depending on the material for forming the light interference layer. For example, when the light interference layer is a positive C plate using a liquid crystal compound, the light interference layer may be formed by preparing a composition containing a liquid crystal compound constituting the positive C plate, applying the composition to the surface of the laminated reflective layer, drying, and then curing the liquid crystal compound by ultraviolet irradiation or the like. Furthermore, when the light interference layer is a hard coat layer, the light interference layer may be formed by preparing a composition containing a polymerizable compound that will become the hard coat layer, applying the composition to the surface of the laminated reflective layer, drying, and then curing the polymerizable compound by ultraviolet irradiation or the like. Furthermore, when the light interference layer is a photo-alignment film, the light interference layer may be formed by preparing a composition containing a compound that forms a photo-alignment film, applying the composition to the surface of the laminated reflective layer, drying, and then curing the polymerizable compound by ultraviolet irradiation or the like. In this example, the optical interference layer is formed on the laminated reflective layer, but conversely, the optical interference layer may be formed first, and then the reflective layer (cholesteric liquid crystal layer) may be formed on this optical interference layer using the above-mentioned composition.

[0077] Furthermore, an adhesive layer is formed on this light interference layer to obtain the optical laminate of the present invention. There is no limitation on the method for forming the adhesive layer, and various known methods depending on the material for forming the adhesive layer can be used. Therefore, the adhesive layer may be formed by a coating method or by adhering a sheet-like pressure-sensitive adhesive layer.

[0078] Furthermore, in the optical laminate of the present invention, the adhesive layer may be formed when the optical laminate of the present invention is attached to an optical member (optical component) using the optical laminate of the present invention. For example, a composition for forming an adhesive layer may be applied to an optical member (optical component) using the optical laminate of the present invention and / or the light interference layer of a laminate of a laminated reflective layer and a light interference layer prepared as described above, and the adhesive layer may be used to bond the optical member to the laminate of a laminated reflective layer and a light interference layer, thereby forming an adhesive layer on the optical laminate of the present invention. Alternatively, an adhesive layer made of a pressure-sensitive adhesive or the like may be provided on an optical member (optical component) using the optical laminate of the present invention, and the laminate of a laminated reflective layer and a light interference layer prepared as described above may be laminated on the adhesive layer with the light interference layer side facing the adhesive layer and attached to the adhesive layer, thereby forming an adhesive layer on the optical laminate of the present invention.

[0079] Furthermore, when the optical laminate of the present invention is used as a reflective circular polarizer, the reflection wavelength range of the reflective circular polarizer may shift to the short wavelength side when the reflective circular polarizer is stretched or molded. Therefore, it is preferable to manufacture the optical laminate in advance, taking into account the wavelength shift of the reflection wavelength range. For example, when an optical laminate including a layer formed by fixing a cholesteric liquid crystal phase is used as a reflective circular polarizer, the optical laminate may be stretched by stretching and molding, which may result in a smaller helical pitch of the cholesteric liquid crystal phase. Therefore, it is preferable to set the helical pitch of the cholesteric liquid crystal phase to a large value in advance. Furthermore, in consideration of a short-wave shift of the reflection wavelength range due to stretching and molding, the optical laminate preferably has an infrared light-reflecting layer having a reflectance of 40% or more at a wavelength of 800 nm. Furthermore, when the stretching ratio during stretching and molding is not uniform in the plane, an appropriate reflection wavelength range may be selected at each location in the plane of the optical laminate in accordance with the wavelength shift due to stretching, and the optical laminate may be manufactured. In other words, there may be regions in the plane of the optical laminate with different reflection wavelength ranges. It is also preferable to set the reflection wavelength range wider than the necessary wavelength range in advance, assuming that the stretching ratio will be different at different locations within the plane of the optical laminate.

[0080] The above describes a method of forming a cholesteric liquid crystal layer by applying a composition for forming a cholesteric liquid crystal layer directly onto each cholesteric liquid crystal layer, and a method of forming a light interference layer by applying a composition for forming a light interference layer directly onto a reflective layer consisting of a cholesteric liquid crystal layer. However, the method for producing the optical laminate of the present invention is not limited to this, and the cholesteric liquid crystal layer and / or the light interference layer may be formed by applying the cholesteric liquid crystal layer and / or the light interference layer to separate substrates, and the cholesteric liquid crystal layer and the light interference layer may be laminated via an adhesive layer (sticking layer) such as an adhesive layer or a pressure-sensitive adhesive layer.

[0081] Any commercially available adhesive can be used as the adhesive for the adhesive layer. Here, from the viewpoint of thinning and reducing the surface roughness Ra, the adhesive preferably has a thickness of 25 μm or less, more preferably 15 μm or less, and even more preferably 6 μm or less. Furthermore, it is preferable that the adhesive is less likely to outgas. In particular, when stretching and molding are performed, a vacuum process and a heating process may be performed, and it is preferable that the adhesive does not outgas even under these conditions. Any commercially available adhesive can be used as the adhesive for the adhesive layer, and for example, an epoxy resin-based adhesive or an acrylic resin-based adhesive can be used. From the viewpoint of thinning and reducing the surface roughness Ra of a reflective circular polarizer using the optical laminate, the adhesive preferably has a thickness of 25 μm or less, more preferably 5 μm or less, and even more preferably 1 μm or less. Furthermore, from the viewpoint of thinning the adhesive layer and applying the adhesive to the adherend with a uniform thickness, the adhesive preferably has a viscosity of 300 cP or less, more preferably 100 cP or less. Furthermore, when the adherend has surface irregularities, the pressure-sensitive adhesive and adhesive can be selected to have an appropriate viscoelasticity or thickness so as to embed the surface irregularities of the layer to be adhered, from the viewpoint of reducing the surface roughness Ra of the reflective circular polarizer using the optical laminate. From the viewpoint of embedding the surface irregularities, the pressure-sensitive adhesive and adhesive preferably have a viscosity of 50 cP or more. Furthermore, the thickness is preferably greater than the height of the surface irregularities. As a method for adjusting the viscosity of the adhesive, for example, a method using an adhesive containing a solvent can be mentioned. In this case, the viscosity of the adhesive can be adjusted by adjusting the ratio of the solvent. Furthermore, the thickness of the adhesive can be further reduced by applying the adhesive to the adherend and then drying the solvent.

[0082] In the optical laminate of the present invention, from the viewpoint of reducing reflection at the interface and suppressing a decrease in the degree of polarization of transmitted light, it is preferable that the pressure-sensitive adhesive or adhesive used for bonding each layer has a small difference in refractive index with the adjacent layer. Since the cholesteric liquid crystal layer has birefringence and therefore has different refractive indices in the fast axis direction and the slow axis direction, the average refractive index n of the liquid crystal layer is determined by adding the refractive indices in the fast axis direction and the slow axis direction and dividing the sum by 2. ａｖｅ When the refractive index of the adjacent adhesive layer or bonding layer is n ａｖｅ The difference between these refractive indices is preferably 0.075 or less, more preferably 0.05 or less, and even more preferably 0.025 or less. The refractive index of the pressure-sensitive adhesive or adhesive can be adjusted by mixing, for example, titanium oxide fine particles and zirconia fine particles.

[0083] It is also preferable that the adhesive layer between each layer has a thickness of 100 nm or less. When the adhesive layer is 100 nm or less, the refractive index difference is less noticeable for visible light, suppressing unnecessary reflection. The adhesive layer thickness is more preferably 50 nm or less, and even more preferably 30 nm or less. An example of a method for forming an adhesive layer having a thickness of 100 nm or less is vapor deposition of a ceramic adhesive such as silicon oxide (SiOx layer) onto the bonding surface. The bonding surface of the bonding member can be subjected to surface modification treatments such as plasma treatment, corona treatment, and saponification treatment before bonding, and a primer layer can be applied. Furthermore, when there are multiple bonding surfaces, the type and thickness of the adhesive layer can be adjusted for each bonding surface. Specifically, an adhesive layer having a thickness of 100 nm or less can be formed, for example, by the following steps (1) to (3): (1) The layers to be laminated are bonded to a temporary support made of a glass substrate. (2) A SiOx layer having a thickness of 100 nm or less is formed on both the surface of the layer to be laminated and the surface of the layer to be laminated by vapor deposition or the like. Vapor deposition can be performed using, for example, a vapor deposition device manufactured by ULVAC (model number ULEYES) using SiOx powder as a vapor deposition source. It is also preferable to subject the surface of the formed SiOx layer to plasma treatment. (3) After the formed SiOx layers are bonded together, the temporary support is peeled off. The bonding is preferably performed at a temperature of, for example, 120°C.

[0084] The coating, adhesion, or lamination of each layer may be performed by roll-to-roll or sheet-fed. The roll-to-roll method is preferred from the viewpoint of improving productivity and reducing axial misalignment of each layer. On the other hand, the sheet-fed method is preferred because it is suitable for small-lot, high-mix production and because it allows the selection of a special adhesion method such as the above-mentioned adhesive layer thickness of 100 nm or less. Furthermore, examples of methods for applying the adhesive to the adherend include known methods such as roll coating, gravure printing, spin coating, wire bar coating, extrusion coating, direct gravure coating, reverse gravure coating, die coating, spraying, and inkjet printing.

[0085] The reflective circular polarizer using the optical laminate of the present invention may include a support and an alignment layer, but the support and alignment layer may be a temporary support that is peeled off and removed when producing the laminated optical film described below. Using a temporary support is preferable because the laminated optical film can be thinned by transferring the reflective circular polarizer to another laminate and then peeling off and removing the temporary support. Furthermore, the adverse effect of the retardation of the temporary support on the polarization degree of transmitted light can be eliminated. The type of support is not particularly limited, but it is preferably transparent to visible light. For example, films such as cellulose acylate, polycarbonate, polysulfone, polyethersulfone, polyacrylate and polymethacrylate, cyclic polyolefin, polyolefin, polyamide, polystyrene, and polyester can be used. Among these, cellulose acylate film, cyclic polyolefin, polyacrylate, and polymethacrylate are preferred. Commercially available cellulose acetate films (e.g., "TD80U" and "Z-TAC" manufactured by Fujifilm Corporation) can also be used. When the support is a temporary support, a support with high tear strength is preferred from the viewpoint of preventing breakage during peeling. For example, polycarbonate and polyester films are preferred. In addition, the support preferably has a small retardation from the viewpoint of suppressing adverse effects on the polarization degree of transmitted light. Specifically, the magnitude of Re at 550 nm is preferably 10 nm or less, and the absolute value of the magnitude of Rth is preferably 50 nm or less. In addition, even if the support is used as the above-mentioned temporary support, it is preferable that the retardation of the temporary support is small in order to perform quality inspection of reflective circular polarizers and other laminates in the manufacturing process of the laminated optical film described below.

[0086] Furthermore, in order to minimize the influence on various sensors that use near-infrared light as a light source, such as those for eye tracking, facial expression recognition, and iris authentication, which are incorporated into optical systems such as virtual reality display devices and electronic viewfinders, it is preferable that the reflective circular polarizer using an optical laminate used in the laminated optical film described below be transparent to near-infrared light.

[0087] [Laminated optical film] The laminated optical film of the present invention has at least a reflective circular polarizer, a retardation layer that converts circularly polarized light into linearly polarized light, and a linear polarizer in this order. In the laminated optical film of the present invention, the above-mentioned optical laminate (first embodiment) of the present invention is used as the reflective circular polarizer. A preferred embodiment of the optical laminate (first embodiment) is as described above.

[0088] As a suitable example of use of the optical laminate of the present invention and the laminated optical film including the same, a virtual reality display device using the laminated optical film of the present invention will be taken up, and the function of the laminated optical film of the present invention will be described in detail. The virtual reality display device of the present invention includes the optical component of the present invention described below.

[0089] FIG. 3 is a schematic diagram of a virtual reality display device using the laminated optical film of the present invention. In the virtual reality display device of the embodiment shown in FIG. 3, a laminated optical film 100 having a reflective circular polarizer using the optical laminate, a lens 200, a half mirror 300, a circular polarizer 400, and an image display panel 500 are arranged in this order from the viewing side. Furthermore, in the laminated optical film 100, a linear polarizer, a retardation layer, and a reflective circular polarizer are arranged in this order from the viewing side. The laminated optical film 100 is attached to the lens 200 by the reflective circular polarizer, i.e., the adhesive layer of the optical laminate of the present invention. In this example, as an example, the circular polarizer 400 converts the light (image) emitted by the image display panel 500 into right-handed circularly polarized light and transmits it. Furthermore, the reflective layer of the laminated reflective layer constituting the reflective circular polarizer is a cholesteric liquid crystal layer that selectively reflects right-handed circularly polarized light. Furthermore, in the laminated optical film 100, the retardation layer and the linear polarizer have their slow axes and transmission axes set so that when left-handed circularly polarized light is incident from the retardation layer side, the converted linearly polarized light is transmitted.

[0090] As shown in FIG. 3 , a light ray 1000 (a light ray 1000 forming a virtual image) emitted from the image display panel 500 passes through the circular polarizing plate 400 to become circularly polarized light (right-handed circularly polarized light) and then passes through the half mirror 300. The light ray then enters the laminated optical film 100 of the present invention from the reflective circular polarizer side, is totally reflected, is reflected again by the half mirror 300, and again enters the laminated optical film 100. At this time, the light ray 1000 has been reflected by the half mirror, becoming circularly polarized light (left-handed circularly polarized light) with a rotation direction opposite to that of the circularly polarized light when it first entered the laminated optical film 100. Therefore, the light ray 1000 passes through the laminated optical film 100 and is visually recognized by the user. Furthermore, when the light ray 100 is reflected by the half mirror 300, the half mirror has a concave mirror shape, so that the image displayed on the image display panel 500 is enlarged by the half mirror 300 and the lens 200, allowing the user to view the enlarged virtual image. The above-mentioned mechanism is called a reciprocating optical system or a folded optical system.

[0091] On the other hand, Figure 4 is a schematic diagram for explaining a case where a ghost occurs in the virtual reality display device shown in Figure 3. More specifically, it is a schematic diagram showing a case where, when a light ray 2000 (a light ray 2000 forming a ghost) is incident on the laminated optical film 100 for the first time in a virtual reality display device, it is transmitted without being properly reflected, resulting in leakage light. As shown in Figure 4, when the light ray 2000 is incident on the laminated optical film 100 for the first time and is transmitted without being reflected, resulting in leakage light, the user will see an image that is not magnified, as can be seen from Figure 4. This image is called a ghost or the like, and it is desired to reduce it.

[0092] Here, as described above, the reflective circular polarizer, i.e., the optical laminate of the present invention, has a light interference layer between the adhesive layer and the laminated reflective layer. Therefore, this ghost can be reduced. A detailed explanation will be given below with reference to Figures 6 and 7. Note that Figures 6 and 7 illustrate the optical laminate 10 shown in Figure 1 as an example.

[0093] As conceptually shown in FIG. 7 , right-handed circularly polarized light (light ray 1000) that is emitted from the image display panel 500 and transmitted through the circular polarizer 400 enters from the lens 200 side, transmits through the adhesive layer 28, and is reflected by the reflective layers A21a to B24b toward the adhesive layer 28. At this time, a portion of this right-handed circularly polarized light (light ray 1000) is reflected at the interface between the adhesive layer 28 and the reflective layer A21a. At this time, the right-handed circularly polarized light is converted into left-handed circularly polarized light. Therefore, this left-handed circularly polarized light (light ray 2000) transmits through the reflective layers A21a to B24b, the retardation layer, and the linear polarizer, i.e., the laminated optical film 100, and is visually recognized by the user as a ghost.

[0094] In contrast, the optical laminate of the present invention has a light interference layer 27 between an adhesive layer 28 and a reflective layer A21a (laminated reflective layer), as conceptually shown in Fig. 6. As described above, in the present invention, when the refractive index of the adhesive layer 28 adjacent to the light interference layer 27 is nA and the average refractive index of the reflective layer (reflective layer A21a) adjacent to the light interference layer is nL, the refractive index nI of the light interference layer 27 is given by (nA x nL). １／２ −0.03≦nI≦(nA×nL) １／２ +0.03 is satisfied. Therefore, the optical laminate of the present invention can reduce the difference in refractive index at the interface of the layer between the laminated reflective layer (reflective layer) and the adhesive layer. In the illustrated example, the difference in refractive index between the reflective layer (reflective layer A21a) adjacent to the optical interference layer of the laminated reflective layer and the optical interference layer 27, and the difference in refractive index between the optical interference layer 27 and the adhesive layer 28 can be reduced. This allows the optical laminate of the present invention to reduce interfacial reflection at the interface between the adhesive layer 28 and the reflective layer A21a, i.e., the interface between the reflective layer A21a and the optical interference layer 27, and the interface between the optical interference layer 27 and the adhesive layer 28. Note that, in FIG. 6, for simplicity, only the interfacial reflection between the optical interference layer 27 and the adhesive layer 28 is illustrated. By having such a configuration, the optical laminate of the present invention can suppress changes in the rotation direction of circularly polarized light caused by interfacial reflection, for example, the conversion of right-handed circularly polarized light (light ray 1000) to left-handed circularly polarized light (light ray 2000). As a result, ghosting can be reduced by using the optical laminate of the present invention as a reflective circular polarizer in a virtual reality display device, for example.

[0095] Additionally, in the optical laminate of the present invention, the film thickness of the light interference layer 27 is in the range of 60 to 110 nm or 230 to 330 nm. As described above, in the optical laminate of the present invention, the difference in refractive index between the reflective layer A21a adjacent to the light interference layer 27 and the light interference layer 27, and the difference in refractive index between the light interference layer 27 and the adhesive layer 28 are small, thereby reducing reflection at this interface. However, some interfacial reflection still occurs between the two interfaces. In contrast, in the optical laminate of the present invention, the film thickness of the light interference layer 27, i.e., the distance between the interfaces that reflect light, is set to the above-mentioned range. In the present invention, this configuration allows for an appropriate shift in the phase of light (light ray 2000) reflected at the interface between the reflective layer A21a and the light interference layer 27 from the phase of light (light ray 2000) reflected at the interface between the light interference layer 27 and the adhesive layer 28. In the present invention, this configuration preferably allows the phase of light reflected at the interface between the reflective layer A21a and the optical interference layer 27 to be shifted by λ / 2 from the phase of light reflected at the interface between the optical interference layer 27 and the adhesive layer 28. Therefore, the optical laminate of the present invention allows the reflected lights at both interfaces to cancel each other out. As a result, the optical laminate of the present invention can further reduce ghosts caused by reflection of unnecessary light at the interfaces.

[0096] In addition, the laminated optical film 100 of the present invention, which has a laminated reflective layer including the reflective layer A and the reflective layer B, has a high degree of polarization. Therefore, it is possible to reduce leakage of transmitted light (i.e., ghost) when a light ray is incident on the laminated optical film 100 for the first time. Furthermore, since the laminated optical film 100 of the present invention has a high degree of polarization even for transmitted light, it is possible to increase the transmittance when a light ray is incident on the laminated optical film 100 for the second time, thereby improving the brightness of the virtual image and further suppressing coloring of the virtual image.

[0097] As shown in FIGS. 3 and 4 , the laminated optical film 100 may be molded onto a curved surface such as a lens. Conventional optical films, which are conventionally known as reflective circular polarizers and are formed by laminating a reflective linear polarizer and a retardation layer having a quarter-wavelength phase difference, have optical axes such as a transmission axis, a reflection axis, and a slow axis. Therefore, when stretched and molded into a curved shape, the optical axes are distorted, resulting in a decrease in the degree of polarization of transmitted light. In contrast, the laminated optical film 100 of the present invention has a reflective circular polarizer (optical laminate) that does not have an optical axis, so the degree of polarization is less likely to decrease due to stretching and molding. Therefore, the laminated optical film 100 is less likely to experience a decrease in the degree of polarization even when molded into a curved shape.

[0098] An example of the layer structure of the laminated optical film 100 of the present invention is shown in FIG. 5. The laminated optical film 100 shown in FIG. 5 has a reflective circular polarizer 103, a positive C plate 104, a retardation layer 105, and a linear polarizer 106 arranged in this order. As described above, the optical laminate of the present invention is used for the reflective circular polarizer 103. Note that the laminated optical film 100 shown in FIG. 5 has a positive C plate 104 as a preferred embodiment, but the laminated optical film of the present invention does not necessarily have the positive C plate 104. The laminated optical film of the present invention has a reflective circular polarizer 103, a retardation layer 105 that converts circularly polarized light into linearly polarized light, and a linear polarizer 106, in this order. Therefore, leakage light from the reflective circular polarizer 103 can be converted into linearly polarized light and then absorbed by the linear polarizer. This increases the degree of polarization of the transmitted light. When the laminated optical film is stretched or molded, there is a concern that the slow axis of the retardation layer and the absorption axis of the linear polarizer may be distorted. However, as described above, the reflective circular polarizer maintains a high degree of polarization even after stretching and molding, and the amount of leaked light from the reflective circular polarizer is small, so that the increase in leaked light is kept to a small amount.

[0099] Furthermore, the laminated optical film of the present invention preferably has a surface roughness Ra of 100 nm or less. A small Ra can improve the sharpness of images, for example, when the laminated optical film is used in a virtual reality display device or the like. The present inventors presume that when light is reflected from the laminated optical film, unevenness distorts the angle of the reflected light, leading to image distortion and blurring. The Ra of the laminated optical film is more preferably 50 nm or less, even more preferably 30 nm or less, and particularly preferably 10 nm or less. The laminated optical film of the present invention is produced by laminating multiple layers. According to the inventors' studies, it has been found that laminating another layer on an uneven layer can amplify the unevenness. Therefore, in the laminated optical film of the present invention, it is preferable that all layers have a small Ra. Each layer of the laminated optical film of the present invention preferably has an Ra of 50 nm or less, more preferably 30 nm or less, and even more preferably 10 nm or less. From the viewpoint of improving the image sharpness of the reflected image, it is particularly preferable that the Ra of the reflective circular polarizer is small. The surface roughness Ra can be measured, for example, using a non-contact surface / layer cross-sectional shape measurement system, VertScan (manufactured by Ryoka Systems Co., Ltd.). Since VertScan is a surface shape measurement method that utilizes the phase of reflected light from a sample, when measuring a reflective circular polarizer (the above-mentioned optical laminate) consisting of a reflective layer with a fixed cholesteric liquid crystal phase, reflected light from inside the film may be superimposed, making it impossible to accurately measure the surface shape. In this case, a metal layer may be formed on the surface of the sample to increase the surface reflectance and further suppress reflection from inside. For example, a sputtering method is used to form a metal layer on the surface of the sample. Examples of sputtering materials include Au, Al, and Pt.

[0100] The laminated optical film of the present invention preferably has a small number of point defects per unit area. Since the laminated optical film of the present invention is produced by stacking multiple layers, it is preferable that the number of point defects in each layer is also small in order to reduce the number of point defects in the entire laminated optical film. Specifically, the number of point defects in each layer is preferably 20 or less per square meter, more preferably 10 or less, and even more preferably 1 or less. For the entire laminated optical film, the number of point defects is preferably 100 or less per square meter, more preferably 50 or less, and even more preferably 5 or less. Point defects reduce the degree of polarization of transmitted light and reduce image sharpness, so it is preferable to have few point defects. Here, point defects include foreign matter, scratches, dirt, film thickness fluctuations, and poor alignment of liquid crystal compounds. Furthermore, the number of point defects described above is preferably counted as the number of point defects with a size of 100 μm or more, more preferably 30 μm or more, and even more preferably 10 μm or more.

[0101] In addition, various sensors using near-infrared light as a light source, such as for eye tracking, facial expression recognition, and iris authentication, may be incorporated into optical systems such as virtual reality display devices and electronic viewfinders, and in order to minimize the influence on the sensors, it is preferable that the laminated optical film of the present invention is transparent to near-infrared light.

[0102] [Retardation Layer] The retardation layer used in the laminated optical film of the present invention has the function of converting incident circularly polarized light into approximately linearly polarized light. For example, a retardation layer having an Re of approximately 1 / 4 wavelength at any wavelength in the visible range can be used. In this case, the in-plane retardation Re(550) at a wavelength of 550 nm is preferably 120 to 150 nm, more preferably 125 to 145 nm, and even more preferably 135 to 140 nm. In addition, retardation layers having an Re of approximately 3 / 4 wavelength and an Re of approximately 5 / 4 wavelength are also preferred because they can convert linearly polarized light into circularly polarized light.

[0103] In addition, the retardation layer used in the laminated optical film of the present invention preferably has reverse dispersion with respect to wavelength. Reverse dispersion is preferable because it makes it possible to convert circularly polarized light into linearly polarized light over a wide wavelength range in the visible region. Here, having reverse dispersion with respect to wavelength means that the value of the retardation at that wavelength increases as the wavelength increases. A retardation layer having reverse dispersion can be produced by uniaxially stretching a polymer film such as a modified polycarbonate resin film having reverse dispersion, for example, with reference to JP 2017-049574 A. In addition, a retardation layer having reverse dispersion may be produced by substantially having reverse dispersion. For example, as disclosed in Japanese Patent No. 06259925, a retardation layer having an Re of approximately 1 / 4 wavelength and a retardation layer having an Re of approximately 1 / 2 wavelength can be produced by laminating them so that their slow axes form an angle of approximately 60 °. In this case, even if the 1 / 4 wavelength retardation layer and the 1 / 2 wavelength retardation layer each have normal dispersion (the retardation value at the wavelength decreases as the wavelength increases), it is known that circularly polarized light can be converted into linearly polarized light over a wide wavelength range in the visible range, and can be considered to have substantially reverse dispersion. In this case, it is preferable that the laminated optical film of the present invention has a reflective circular polarizer, a 1 / 4 wavelength retardation layer, a 1 / 2 wavelength retardation layer, and a linear polarizer in this order.

[0104] In addition, the retardation layer used in the laminated optical film of the present invention preferably has a layer formed by fixing a uniformly aligned liquid crystal compound. For example, a layer in which a rod-shaped liquid crystal compound is uniformly aligned horizontally relative to the in-plane direction, and a layer in which a discotic liquid crystal compound is uniformly aligned perpendicularly to the in-plane direction can be used. Furthermore, for example, referring to JP-A-2020-084070, a retardation layer having reverse dispersion can also be produced by uniformly aligning and fixing a rod-shaped liquid crystal compound having reverse dispersion.

[0105] In addition, the retardation layer used in the laminated optical film of the present invention preferably has a layer formed by fixing a liquid crystal compound that is twisted and aligned with the thickness direction as the helical axis.For example, as disclosed in Japanese Patent No. 05753922 and Japanese Patent No. 05960743, a retardation layer having a layer formed by fixing a rod-shaped liquid crystal compound or a discotic liquid crystal compound that is twisted and aligned with the thickness direction as the helical axis can also be used.In this case, the retardation layer can be considered to have substantially reverse dispersion, which is preferable.

[0106] The thickness of the retardation layer is not particularly limited, but from the viewpoint of thinning, it is preferably 0.1 to 8 μm, more preferably 0.3 to 5 μm.

[0107] In the laminated optical film of the present invention, the retardation layer may include a support and an alignment layer. The support and alignment layer may also be temporary supports that are peeled off and removed when preparing the laminated optical film. Using a temporary support is preferable because the laminated optical film can be thinned by transferring the retardation layer to another laminate and then peeling off and removing the temporary support. Furthermore, the adverse effect of the retardation of the temporary support on the polarization degree of transmitted light can be eliminated. The type of support is not particularly limited, but it is preferably transparent to visible light. For example, films such as cellulose acylate, polycarbonate, polysulfone, polyethersulfone, polyacrylate, polymethacrylate, cyclic polyolefin, polyolefin, polyamide, polystyrene, and polyester can be used. Among these, cellulose acylate film, cyclic polyolefin, polyacrylate, and polymethacrylate are preferred. Furthermore, commercially available cellulose acetate films can also be used as the support. Examples of commercially available cellulose acetate films include "TD80U" and "Z-TAC" manufactured by Fujifilm Corporation. When the support is a temporary support, a support with high tear strength is preferred from the viewpoint of preventing breakage during peeling. For example, polycarbonate and polyester films are preferred. Furthermore, the support preferably has a small retardation from the viewpoint of suppressing adverse effects on the polarization degree of transmitted light. Specifically, the magnitude of Re(550) is preferably 10 nm or less, and the absolute value of Rth is preferably 50 nm or less. Furthermore, even if the support is used as the above-mentioned temporary support, it is preferable that the retardation of the temporary support is small in order to perform quality inspection of the retardation layer and other laminates in the manufacturing process of the laminated optical film.

[0108] In addition, in order to minimize the influence on various sensors that use near-infrared light as a light source, such as those for eye tracking, facial expression recognition, and iris authentication, which are incorporated into optical systems such as virtual reality display devices and electronic viewfinders, the retardation layer used in the laminated optical film of the present invention is preferably transparent to near-infrared light.

[0109] [Linear Polarizer] The linear polarizer used in the laminated optical film of the present invention is preferably an absorption-type linear polarizer. An absorption-type linear polarizer absorbs linearly polarized light in the absorption axis direction of incident light and transmits linearly polarized light in the transmission axis direction. A typical linear polarizer can be used as the linear polarizer. For example, a polarizer obtained by dyeing a dichroic material onto polyvinyl alcohol or other polymer resin and stretching the material to orient the material, or a polarizer obtained by aligning a dichroic material by utilizing the orientation of a liquid crystal compound, may be used. From the viewpoints of availability and increasing the polarization degree, a polarizer obtained by dyeing polyvinyl alcohol with iodine and stretching the material is preferred. The thickness of the linear polarizer is preferably 10 μm or less, more preferably 7 μm or less, and even more preferably 5 μm or less. A thin linear polarizer can prevent cracking and breakage of the film when the laminated optical film is stretched or molded. The single-plate transmittance of the linear polarizer is preferably 40% or more, more preferably 42% or more. The degree of polarization is preferably 90% or more, more preferably 95% or more, and even more preferably 99% or more. In this specification, the single-plate transmittance and degree of polarization of the linear polarizer are measured using an automatic polarizing film measuring device: VAP-7070 (manufactured by JASCO Corporation). The direction of the transmission axis of the linear polarizer preferably coincides with the direction of the polarization axis of light converted into linearly polarized light by the retardation layer. For example, when the retardation layer is a layer having a retardation of 1 / 4 wavelength, the angle between the transmission axis of the linear polarizer and the slow axis of the retardation layer is preferably approximately 45°.

[0110] The linear polarizer used in the laminated optical film of the present invention is also preferably a light-absorbing anisotropic layer containing a liquid crystal compound and a dichroic material. Linear polarizers containing a liquid crystal compound and a dichroic material are preferred because they can be made thin and are less likely to crack or break even when stretched and molded. The thickness of the light-absorbing anisotropic layer is not particularly limited, but from the viewpoint of thinning, it is preferably 0.1 to 8 μm, more preferably 0.3 to 5 μm. Linear polarizers containing a liquid crystal compound and a dichroic material can be produced, for example, with reference to JP 2020-023153 A. From the viewpoint of improving the polarization degree of the linear polarizer, the light-absorbing anisotropic layer preferably has an orientation degree of the dichroic material of 0.95 or more, more preferably 0.97 or more.

[0111] The liquid crystal compound contained in the composition for forming the optically absorbing anisotropic layer is preferably a liquid crystal compound that does not exhibit dichroism in the visible range. Both low-molecular-weight liquid crystal compounds and high-molecular-weight liquid crystal compounds can be used as the liquid crystal compound. Here, "low-molecular-weight liquid crystal compound" refers to a liquid crystal compound that does not have a repeating unit in its chemical structure. Furthermore, "high-molecular-weight liquid crystal compound" refers to a liquid crystal compound that has a repeating unit in its chemical structure. Examples of high-molecular-weight liquid crystal compounds include the thermotropic liquid crystal polymers described in JP 2011-237513 A. Furthermore, high-molecular-weight liquid crystal compounds preferably have a crosslinkable group at their terminals. Examples of crosslinkable groups at the terminals of high-molecular-weight liquid crystal compounds include acryloyl groups and methacryloyl groups. The liquid crystal compounds may be used alone or in combination. It is also preferable to use a high-molecular-weight liquid crystal compound in combination with a low-molecular-weight liquid crystal compound. The content of the liquid crystal compound is preferably 25 to 2,000 parts by mass, more preferably 33 to 1,000 parts by mass, and even more preferably 50 to 500 parts by mass, relative to 100 parts by mass of the content of the dichroic substance in the composition. When the content of the liquid crystal compound is within the above range, the degree of orientation of the polarizer is further improved.

[0112] The dichroic substance contained in the composition for forming an optically absorptive anisotropic layer for forming the optically absorptive anisotropic layer is not particularly limited, and examples thereof include visible light absorbing substances (dichroic dyes), ultraviolet absorbing substances, infrared absorbing substances, nonlinear optical substances, carbon nanotubes, etc., and any conventionally known dichroic substance (dichroic dye) can be used. In the present invention, two or more dichroic substances may be used in combination. For example, from the viewpoint of obtaining a high degree of polarization over a wider wavelength range, it is preferable to use in combination at least one dichroic substance having a maximum absorption wavelength in the wavelength range of 370 to 550 nm and at least one dichroic substance having a maximum absorption wavelength in the wavelength range of 500 to 700 nm.

[0113] When the linear polarizer of the present invention is composed of a light-absorbing anisotropic layer containing a liquid crystal compound and a dichroic material, the linear polarizer may include a support, an alignment layer, etc., but the support and alignment layer may be a temporary support that is peeled off when producing a laminated optical film. Using a temporary support is preferable because the laminated optical film can be made thinner by peeling off and removing the temporary support after transferring the light-absorbing anisotropic layer to another laminate, and the adverse effect of the retardation of the temporary support on the polarization degree of transmitted light can be eliminated. The type of support is not particularly limited, but it is preferably transparent to visible light. For example, a support similar to the support used for the retardation layer can be used. Preferred embodiments of the support used for the linear polarizer are the same as those of the support used for the retardation layer.

[0114] Furthermore, in order to minimize the influence on various sensors that use near-infrared light as a light source, such as those for eye tracking, facial expression recognition, and iris authentication, which are incorporated into optical systems such as virtual reality display devices and electronic viewfinders, the linear polarizer used in the laminated optical film of the present invention is preferably transparent to near-infrared light.

[0115] [Other Functional Layers] The laminated optical film of the present invention may have other functional layers in addition to the reflective circular polarizer, the retardation layer, and the linear polarizer.

[0116] Furthermore, in order to minimize the influence on various sensors that use near-infrared light as a light source, such as eye tracking, facial expression recognition, and iris authentication, which are incorporated into optical systems such as virtual reality display devices and electronic viewfinders, it is preferable that the other functional layers be transparent to near-infrared light.

[0117] <Positive C Plate> As shown in FIG. 5, the laminated optical film of the present invention preferably further includes a positive C plate. Here, the positive C plate is a retardation layer having an Re of substantially zero and an Rth of a negative value. The positive C plate can be obtained, for example, by vertically aligning a rod-shaped liquid crystal compound. For details of the manufacturing method of the positive C plate, see, for example, JP 2017-187732 A, JP 2016-053709 A, and JP 2015-200861 A. The positive C plate functions as an optical compensation layer to increase the degree of polarization of transmitted light with respect to obliquely incident light. The positive C plate can be disposed at any position in the laminated optical film, and multiple positive C plates may be disposed.

[0118] The positive C plate may be disposed adjacent to or inside the reflective circular polarizer. For example, when a reflective layer formed by immobilizing a cholesteric liquid crystal phase containing a rod-shaped liquid crystal compound is used as the reflective circular polarizer, the reflective layer has a positive Rth. In this case, when light is incident on the reflective circular polarizer from an oblique direction, the Rth may change the polarization state of the reflected light and transmitted light, potentially reducing the degree of polarization of the transmitted light. Having a positive C plate inside or near the reflective circular polarizer is preferable because it can further suppress changes in the polarization state of obliquely incident light and further suppress reductions in the degree of polarization of transmitted light, thereby further reducing ghosting. According to the inventors' studies, the positive C plate is preferably disposed on the side of the blue light-reflecting layer opposite the green light-reflecting layer, but may be disposed elsewhere. In this case, the Re(550) of the positive C plate is preferably approximately 10 nm or less, and the Rth(550) is preferably −600 to −100 nm, more preferably −400 to −200 nm.

[0119] The positive C plate may be disposed adjacent to or within the retardation layer. For example, when a layer formed by immobilizing a rod-shaped liquid crystal compound is used as the retardation layer, the retardation layer has a positive Rth. In this case, when light is incident on the retardation layer from an oblique direction, the polarization state of the transmitted light may change due to the action of Rth, resulting in a decrease in the degree of polarization of the transmitted light. Having a positive C plate within or near the retardation layer is preferable because it can suppress changes in the polarization state of obliquely incident light and suppress a decrease in the degree of polarization of the transmitted light. According to the inventors' studies, the positive C plate is preferably disposed on the side of the retardation layer opposite the linear polarizer, but may be disposed elsewhere. In this case, the Re(550) of the positive C plate is preferably approximately 10 nm or less, and the Rth(550) is preferably -90 to -40 nm.

[0120] <Antireflection Layer> The laminated optical film of the present invention preferably has an antireflection layer on its surface. The laminated optical film of the present invention has the function of reflecting specific circularly polarized light and transmitting circularly polarized light orthogonal to it. However, reflection on the surface of the laminated optical film generally includes reflection of unintended polarized light, which may reduce the degree of polarization of the transmitted light. Therefore, it is preferable that the laminated optical film has an antireflection layer on its surface. The antireflection layer may be provided on only one surface of the laminated optical film or on both surfaces. The type of antireflection layer is not particularly limited, but from the viewpoint of further reducing the reflectance, moth-eye films and AR (anti-reflective) films are preferred. Known moth-eye films and AR films can be used. Furthermore, when the laminated optical film is stretched or molded, moth-eye films are preferred because they can maintain high antireflection performance even when the film thickness changes due to stretching. Furthermore, when the antireflection layer includes a support and is stretched and molded, from the viewpoint of facilitating stretching and molding, the peak temperature of the glass transition temperature Tg of the support is preferably 170° C. or less, more preferably 130° C. or less. Specifically, the support is preferably, for example, a PMMA film.

[0121] <Second Retardation Layer> The laminated optical film of the present invention preferably further has a second retardation layer. For example, it may contain a reflective circular polarizer, a retardation layer, a linear polarizer, and a second retardation layer in this order. The second retardation layer preferably converts linearly polarized light into circularly polarized light, and for example, a retardation layer having a ¼ wavelength Re is preferred. The reason for this will be explained below. Light incident on the laminated optical film from the reflective circular polarizer side and transmitted through the reflective circular polarizer, the retardation layer, and the linear polarizer becomes linearly polarized light, and a portion of it is reflected by the outermost surface on the linear polarizer side and then exits again from the surface on the reflective circular polarizer side. Such light is unnecessary reflected light and can be a factor in reducing the degree of polarization of the reflected light, so it is preferable to reduce it. Therefore, there is a method of laminating an antireflection layer to suppress reflection on the outermost surface on the linear polarizer side. However, when the laminated optical film is used by being attached to a medium such as glass or plastic, even if an antireflection layer is provided on the attachment surface of the laminated optical film, reflection on the surface of the medium cannot be suppressed, making it difficult to obtain an antireflection effect. On the other hand, when a second retardation layer that converts linearly polarized light into circularly polarized light is provided, the light that reaches the outermost surface on the linear polarizer side becomes circularly polarized light and is converted into orthogonal circularly polarized light when reflected on the outermost surface of the medium. After that, when the light passes through the second retardation layer again and reaches the linear polarizer, it becomes linearly polarized light in the absorption axis direction of the linear polarizer and is absorbed by the linear polarizer. Therefore, unnecessary reflection can be prevented. From the viewpoint of more effectively suppressing unnecessary reflection, it is preferable that the second retardation layer has substantially reverse dispersion.

[0122] <Support> The laminated optical film of the present invention may further have a support (resin substrate). The support can be installed in any location. For example, when a reflective circular polarizer, a retardation layer, or a linear polarizer is a film to be transferred from a temporary support, the support can be used as the transfer destination. The type of support is not particularly limited, but it is preferably transparent to visible light. For example, films such as cellulose acylate, polycarbonate, polysulfone, polyethersulfone, polyacrylate, polymethacrylate, cyclic polyolefin, polyolefin, polyamide, polystyrene, and polyester can be used. Among these, cellulose acylate film, cyclic polyolefin, polyacrylate, and polymethacrylate are preferred examples. Furthermore, commercially available cellulose acetate film can also be used as the support. Examples of commercially available cellulose acetate films include "TD80U" and "Z-TAC" manufactured by Fujifilm Corporation. In addition, the support preferably has a small retardation from the viewpoint of suppressing adverse effects on the polarization degree of transmitted light and from the viewpoint of facilitating optical inspection of the laminated optical film. Specifically, the magnitude of Re(550) is preferably 10 nm or less, and the absolute value of the magnitude of Rth(550) is preferably 50 nm or less.

[0123] When the laminated optical film of the present invention is to be stretched and molded, the support (resin substrate) preferably has a loss tangent tanδ peak temperature of 170° C. or less. From the viewpoint of enabling molding at low temperatures, the loss tangent tanδ peak temperature is preferably 150° C. or less, more preferably 130° C. or less.

[0124] Here, the method for measuring the loss tangent tanδ will be described. Using a dynamic viscoelasticity measuring device (DVA-200, manufactured by IT Measurement Control Co., Ltd.), a film sample that has been previously conditioned for at least 2 hours in an atmosphere at a temperature of 25°C and a humidity of 60% Rh is measured for E" (loss modulus) and E' (storage modulus) under the following conditions, and the loss tangent tanδ (= E" / E') is determined as the value. Device: DVA-200, manufactured by IT Measurement Control Co., Ltd. Sample: 5 mm, length 50 mm (gap 20 mm) Measurement conditions: tension mode Measurement temperature: -150°C to 220°C Heating condition: 5°C / min Frequency: 1 Hz Note that, in general, in optical applications, resin substrates that have been subjected to a stretching treatment are often used, and the peak temperature of the loss tangent tanδ often becomes high due to the stretching treatment. For example, the peak temperature of tanδ for a TAC (triacetyl cellulose) substrate (TG40, manufactured by Fujifilm Corporation) is 180°C or higher.

[0125] As the support having a peak temperature of loss tangent tanδ of 170°C or less, various resin substrates can be used without any particular limitation. Examples include polyolefins such as polyethylene, polypropylene, and norbornene-based polymers; cyclic olefin-based resins; polyvinyl alcohol; polyethylene terephthalate; acrylic resins such as polymethacrylic acid esters and polyacrylic acid esters; polyethylene naphthalate; polycarbonate; polysulfone; polyethersulfone; polyether ketone; polyphenylene sulfide; and polyphenylene oxide. Among these, cyclic olefin-based resins, polyethylene terephthalate, and acrylic resins are preferred, and cyclic olefin-based resins and polymethacrylic acid esters are particularly preferred, in view of their easy commercial availability and excellent transparency.

[0126] Commercially available resin substrates include Technolloy S001G, Technolloy S014G, Technolloy S000, Technolloy C001, and Technolloy C000 (Sumika Acrylic Sales Co., Ltd.), Lumirror U Type, Lumirror FX10, and Lumirror SF20 (Toray Industries, Inc.), HK-53A (Higashiyama Films Co., Ltd.), Teflex FT3 (Teijin DuPont Films Japan Co., Ltd.), S-Cina and SCA40 (Sekisui Chemical Co., Ltd.), Zeonor Film (Optes Co., Ltd.), and Arton Film (JSR Corporation).

[0127] The thickness of the support is not particularly limited, but is preferably from 5 to 300 μm, more preferably from 5 to 100 μm, and even more preferably from 5 to 30 μm.

[0128] The laminated optical film may also have layers other than those described above. Examples of layers other than those described above include an adhesive layer formed with the adhesive described below, an adhesive layer formed with the adhesive described below, and a refractive index adjustment layer. A refractive index adjustment layer having a smaller difference in refractive index between the fast axis direction and the slow axis direction than that of the reflective circular polarizer may be provided between the reflective circular polarizer and the adhesive, or between the reflective circular polarizer and the adhesive. In this case, the refractive index adjustment layer preferably has a layer formed by fixing the orientation state of cholesteric liquid crystals. By providing a refractive index adjustment layer, interfacial reflection can be further suppressed, and the occurrence of ghosts can be further suppressed. The average refractive index of the refractive index adjustment layer is more preferably smaller than that of the reflective circular polarizer. The central wavelength of the reflected light from the refractive index adjustment layer may be smaller than 430 nm or larger than 670 nm, and is more preferably smaller than 430 nm.

[0129] [Method of Adhesion of Each Layer] The laminated optical film of the present invention is a laminate composed of multiple layers. Each layer can be bonded (attached) using any bonding method, for example, a pressure-sensitive adhesive or adhesive. As the pressure-sensitive adhesive, any commercially available pressure-sensitive adhesive can be used. However, from the viewpoint of thinning and reducing the surface roughness Ra of the laminated optical film, the thickness is preferably 25 μm or less, more preferably 15 μm or less, and even more preferably 6 μm or less. Furthermore, it is preferable that the pressure-sensitive adhesive is one that is less likely to outgas. In particular, when performing stretching and molding, vacuum processes and heating processes may be used, and it is preferable that the pressure-sensitive adhesive does not outgas even under these conditions. As the adhesive, any commercially available adhesive can be used, for example, an epoxy resin-based adhesive or an acrylic resin-based adhesive. From the viewpoint of thinning and reducing the surface roughness Ra of the laminated optical film, the thickness of the adhesive is preferably 25 μm or less, more preferably 5 μm or less, and even more preferably 1 μm or less. Furthermore, from the viewpoint of thinning the adhesive layer and applying the adhesive to the adherend with a uniform thickness, the adhesive preferably has a viscosity of 300 cP or less, more preferably 100 cP or less, and even more preferably 10 cP or less. Furthermore, if the adherend has surface irregularities, the pressure-sensitive adhesive and adhesive can be selected to have an appropriate viscoelasticity or thickness so as to embed the surface irregularities of the layer to be adhered, thereby reducing the surface roughness Ra of the laminated optical film. From the viewpoint of embedding the surface irregularities, the pressure-sensitive adhesive and adhesive preferably have a viscosity of 50 cP or more. Furthermore, the thickness is preferably greater than the height of the surface irregularities. For example, a method of adjusting the viscosity of the adhesive can be used, such as using a solvent-containing adhesive. In this case, the viscosity of the adhesive can be adjusted by adjusting the ratio of the solvent. Furthermore, the thickness of the adhesive can be further reduced by applying the adhesive to the adherend and then drying the solvent.

[0130] In a laminated optical film, from the viewpoint of reducing unnecessary reflection and suppressing a decrease in the degree of polarization of transmitted light and reflected light, it is preferable that the pressure-sensitive adhesive or adhesive used to bond each layer has a small refractive index difference with adjacent layers. Specifically, the refractive index difference between adjacent layers is preferably 0.1 or less, more preferably 0.05 or less, and even more preferably 0.01 or less. The refractive index of the pressure-sensitive adhesive or adhesive can be adjusted, for example, by mixing titanium oxide fine particles and zirconia fine particles. Furthermore, the reflective circular polarizer, retardation layer, and linear polarizer may have in-plane refractive index anisotropy, but it is preferable that the refractive index difference with adjacent layers is 0.05 or less in all directions in the plane. Therefore, the pressure-sensitive adhesive and adhesive may have in-plane refractive index anisotropy.

[0131] It is also preferable that the adhesive layer between each layer has a thickness of 100 nm or less. When the adhesive layer is 100 nm or less, the refractive index difference is less noticeable for visible light, thereby suppressing reflection at the interface. The adhesive layer thickness is more preferably 50 nm or less. An example of a method for forming an adhesive layer having a thickness of 100 nm or less is by vapor-depositing a ceramic adhesive such as silicon oxide (SiOx layer) onto the bonding surface. The bonding surface of the bonding member can be subjected to surface modification treatments such as plasma treatment, corona treatment, and saponification treatment before bonding, and a primer layer can be applied. Furthermore, when there are multiple bonding surfaces, the type and thickness of the adhesive layer can be adjusted for each bonding surface. Specifically, an adhesive layer having a thickness of 100 nm or less can be formed, for example, by the following steps (1) to (3): (1) The layer to be laminated is laminated to a temporary support made of a glass substrate. (2) SiOx layers having a thickness of 100 nm or less are formed on both the surface of the layer to be laminated and the surface of the layer to be laminated by vapor deposition or the like. The deposition can be performed using, for example, a deposition apparatus (model number ULEYES) manufactured by ULVAC, Inc., using SiOx powder as a deposition source. It is also preferable to subject the surface of the formed SiOx layer to plasma treatment. (3) After the formed SiOx layers are bonded together, the temporary support is peeled off. The bonding is preferably performed at a temperature of, for example, 120°C.

[0132] The coating, adhesion, or lamination of each layer may be performed by roll-to-roll or sheet-to-sheet. The roll-to-roll method is preferred from the viewpoint of improving productivity and reducing axial misalignment of each layer. On the other hand, the sheet-to-sheet method is preferred because it is suitable for small-lot, high-mix production and because it allows the selection of a special adhesion method such as the above-mentioned adhesive layer thickness of 100 nm or less. Furthermore, methods for applying the adhesive to the adherend include known methods such as roll coating, gravure printing, spin coating, wire bar coating, extrusion coating, direct gravure coating, reverse gravure coating, die coating, spraying, and inkjet printing.

[0133] [Direct Coating of Each Layer] It is also preferable that there is no adhesive layer between the layers of the laminated optical film of the present invention. When forming a layer, the adhesive layer can be eliminated by directly coating the layer on an adjacent layer that has already been formed. Furthermore, when one or both of the adjacent layers contain a liquid crystal compound, it is preferable that the alignment direction of the liquid crystal compound continuously changes at the interface in order to reduce the refractive index difference in all in-plane directions. For example, a retardation layer containing a liquid crystal compound can be directly coated on a linear polarizer containing a liquid crystal compound and a dichroic material, and the liquid crystal compound in the retardation layer can be continuously aligned at the interface due to the alignment regulating force of the liquid crystal compound in the linear polarizer.

[0134] [Lamination Order of Layers] The laminated optical film of the present invention is composed of many layers, but the order of the lamination steps is not particularly limited and can be selected arbitrarily. For example, when transferring a functional layer from a film consisting of a temporary support and a functional layer, wrinkles and cracks during transfer can be prevented by adjusting the lamination order so that the thickness of the transferred film is 10 μm or more. In addition, from the viewpoint of reducing the surface roughness Ra of the laminated optical film, if another layer is laminated on a layer with large surface irregularities, the surface irregularities may be further amplified, so it is preferable to laminate the layers in order from the layer with the smallest surface roughness Ra. In addition, the lamination order can also be selected from the viewpoint of quality evaluation in the production process of the laminated optical film. For example, layers other than the reflective circular polarizer may be laminated and quality evaluation may be performed using a transmission optical system, and then the reflective circular polarizer may be laminated and quality evaluation may be performed using a reflection optical system. In addition, the lamination order can also be selected from the viewpoint of improving the production yield of the laminated optical film and reducing costs.

[0135] [Applications of the Laminated Optical Film of the Present Invention] The laminated optical film of the present invention can be used as a reflective polarizer incorporated into in-vehicle rearview mirrors, virtual reality display devices, electronic viewfinders, and the like, as described in, for example, Patent Documents 4 and 5. In particular, in virtual reality display devices and electronic viewfinders, etc., having a reciprocating optical system in which light is reflected and reciprocated between a reflective polarizer and a half mirror, the laminated optical film of the present invention is very useful from the viewpoint of improving the clarity of the displayed image. Furthermore, virtual reality display devices and electronic viewfinders, etc., having a reciprocating optical system may have optical films such as an absorptive polarizer and a circular polarizer in addition to the reflective polarizer. However, the clarity of the displayed image can be further improved by using some of the members and bonding methods used in the laminated optical film of the present invention on optical films other than the above-mentioned reflective polarizer.

[0136] <Molding Method> The optical laminate and laminate optical film of the present invention may be used in a flat form or may be molded into any shape. Here, the optical laminate and laminate optical film are collectively referred to as the optical film, and the molding method will be described. The molding method for the optical film includes a step of heating the optical film, a step of pressing the optical film against a mold to deform it according to the shape of the mold, and a step of cutting the optical film.

[0137] [Step of Heating Optical Film] Methods for heating the optical film include heating by contacting with a heated solid, heating by contacting with a heated liquid, heating by contacting with a heated gas, heating by infrared radiation, and heating by microwave radiation. However, heating by infrared radiation, which allows heating remotely just before molding, is preferred.

[0138] The wavelength of the infrared rays used for heating is preferably 1.0 to 30.0 μm, and more preferably 1.5 to 5 μm. Examples of IR light sources that can be used include near-infrared lamp heaters with a tungsten filament sealed in a quartz tube and wavelength-controlled heaters with multiple quartz tubes and a mechanism for cooling a portion of the space between the quartz tubes with air. Furthermore, by creating a temperature distribution within the surface of the optical film, the physical properties during molding can be controlled according to the purpose. Methods for creating a temperature distribution include creating a distribution of the amount of infrared radiation used for heating, controlling the intensity distribution of cooling air, and creating a distribution by controlling the mold temperature and contact time to control the progress of cooling due to contact with the mold. Methods for creating a distribution of infrared radiation include varying the density of IR light sources and placing a filter with a patterned infrared light transmittance between the IR light source and the optical film. Examples of filters with patterned transmittance include glass with metal vapor deposition, cholesteric liquid crystal layers with a reflection band that is infrared-transformed, dielectric multilayer films with a reflection band that is infrared-transformed, and ink that absorbs infrared. The temperature of the optical film is controlled by the strength, duration, and illuminance of the infrared radiation. The temperature of the optical film can be monitored using temperature measurement means such as a non-contact radiation thermometer and a thermocouple, and it can be molded at the target temperature.

[0139] [Step of Pressing the Optical Film Against the Mold and Deforming it to Fit the Mold Shape] The optical film can be pressed against the mold and deformed to fit the mold shape by reducing or pressurizing the molding space. Alternatively, a mold pressing method can be used.

[0140] [Process for Cutting Optical Film] Cutting the molded optical film into any desired shape can be performed using a cutter, scissors, a cutting plotter, a laser cutter, or the like. <Molding Apparatus> One form of molding apparatus is an apparatus consisting of a box 1 having an opening at the top and a box 2 having an opening at the bottom. To form a molding space, the openings of box 1 and box 2 are aligned directly or via other jigs to form a sealed molding space. A mold (also referred to as an adherend) with the shape to be molded and the film to be molded are placed in the molding space. The film acts as a partition, dividing the molding space consisting of box 1 and box 2 into two spaces. The mold is placed on the box 1 side, below the film to be molded. Furthermore, the vacuum molding apparatus is equipped with multiple heating elements for heating the film to be molded. The heating elements may be placed inside the molding space, or they may be placed outside the molding space and heat the film to be molded through a transparent window.

[0141] <Optical Article> The optical component of the present invention includes the optical laminate of the present invention. One embodiment of the optical article of the present invention is a composite lens having a lens and the optical laminate of the present invention or the laminated optical film of the present invention. A half mirror may be formed on one side of the lens. Convex and concave lenses can be used as lenses. Biconvex lenses, plano-convex lenses, and convex meniscus lenses can be used as convex lenses. Biconcave lenses, plano-concave lenses, and concave meniscus lenses can be used as concave lenses. Convex meniscus and concave meniscus lenses are preferred for lenses used in focusing optical systems, with concave meniscus lenses being more preferred in terms of minimizing aberration. Materials for forming the lenses can include glass, crystal, and plastic, which are transparent to visible light. Since birefringence in lenses causes unevenness and noise, low birefringence is preferable, and zero-birefringence materials are more preferred. The laminated optical film of the present invention used in the optical article of the present invention may be flat or curved, but a curved surface is preferred in terms of reducing image distortion and aberration.

[0142] Another embodiment of the optical article of the present invention comprises a prism or a substrate and the optical laminate of the present invention or the laminated optical film of the present invention. Examples of materials for forming the prism and the substrate include glass, crystal, and plastic. These materials may be transparent or opaque to visible light. The birefringence of the prism and the substrate is preferably small, since it can cause unevenness and noise, and materials with zero birefringence are more preferred.

[0143] The features of the present invention will be explained in more detail below with reference to examples. Note that the materials, amounts used, ratios, processing details, processing procedures, etc. shown below can be changed as appropriate without departing from the spirit of the present invention. Furthermore, configurations other than those shown below can also be used without departing from the spirit of the present invention.

[0144] [Preparation of Coating Solution for Reflective Layer]

[0145] <Reflective layer coating solution R-1> The composition shown below was stirred and dissolved in a container kept at 70° C. to prepare a reflective layer coating solution R-1, where R represents a coating solution using a rod-like liquid crystal compound.

[0146] -------------------------------------------------- Coating liquid R-1 for reflective layer -------------------------------------------------- Methyl ethyl ketone 120.9 parts by mass Cyclohexanone 21.3 parts by mass Mixture X of rod-shaped liquid crystal compounds shown below 100.0 parts by mass Photopolymerization initiator B shown below 1.00 part by mass Chiral agent A shown below 4.18 parts by mass Surfactant F1 shown below 0.1 part by mass

[0147] Mixture X of rod-shaped liquid crystal compounds

[0148] In the above mixture X, the numerical values ​​are in mass %. R is a group bonded via an oxygen atom. Furthermore, the average molar absorption coefficient of the above rod-shaped liquid crystal compound in the wavelength range of 300 to 400 nm was 140 / mol cm.

[0149] Chiral agent A

[0150] Surfactant F1

[0151] Photopolymerization initiator B

[0152] Chiral agent A is a chiral agent whose helical twisting power (HTP) is reduced by light.

[0153] <Reflective Layer Coating Solution R-2> This was prepared in the same manner as Reflective Layer Coating Solution R-1, except that the amount of chiral agent A added was changed as shown in Table 1 below.

[0154] Table 1. Amount of chiral agent in coating solution containing rod-shaped liquid crystal compound

[0155] <Reflective layer coating solution D-1> The composition shown below was stirred and dissolved in a container kept at 50° C. to prepare a reflective layer coating solution D-1, where D represents a coating solution using a discotic liquid crystal compound.

[0156] -------------------------------- Coating liquid D-1 for reflective layer ---------------------------------- 80 parts by mass of discotic liquid crystal compound (A) below 20 parts by mass of discotic liquid crystal compound (B) below 10 parts by mass of polymerizable monomer E1 below 0.3 parts by mass of surfactant F2 below 3 parts by mass of photopolymerization initiator (Irgacure 907, manufactured by BASF) 5.45 parts by mass of the above chiral agent A 290 parts by mass of methyl ethyl ketone 50 parts by mass of cyclohexanone --------------------------------

[0157] Discotic Liquid Crystal Compound (A)

[0158] Discotic Liquid Crystal Compound (B)

[0159] Polymerizable Monomer E1

[0160] Surfactant F2

[0161] <Reflective Layer Coating Solutions D-2 and D-3> These were prepared in the same manner as Reflective Layer Coating Solution D-1, except that the amount of chiral agent A added was changed as shown in Table 2 below.

[0162] Table 2. Amount of chiral agent in coating solution containing discotic liquid crystal compound

[0163] <Coating Solution PA-1 for Light Interference Layer> The composition shown below was stirred and dissolved in a container kept at 60° C. to prepare Coating Solution PA-1 for light interference layer.

[0164] -------------------------------- Coating liquid for optical interference layer PA-1 ---------------------------------- Methyl isobutyl ketone 3011.0 parts by mass Mixture X of the above rod-shaped liquid crystal compound 100.0 parts by mass Photopolymerization initiator C described below 5.1 parts by mass Photoacid generator described below 3.0 parts by mass Hydrophilic polymer described below 2.0 parts by mass Vertical alignment agent described below 1.9 parts by mass Viscosity reducer described below 4.2 parts by mass Material for interlayer photoalignment film described below 8.0 parts by mass Stabilizer described below --------------------------------

[0165] Photopolymerization initiator C

[0166] Photoacid generator

[0167] hydrophilic polymer

[0168] Vertical alignment agent

[0169] Viscosity reducer

[0170] Materials for interlayer photo-alignment films

[0171] stabilizers

[0172] [Preparation of Reflective Circular Polarizer 1] A 60 μm thick tack (triacetyl cellulose) film (TG60, manufactured by Fujifilm Corporation) was prepared as a temporary support.

[0173] The coating solution for optical interference layer PA-1 prepared above was applied to the tack film described above using a wire bar coater, and then dried at 80°C for 60 seconds. Thereafter, the coating solution was dried in a low-oxygen atmosphere (100 ppm) at 78°C with an irradiation dose of 300 mJ / cm. ２The liquid crystal compound was cured by irradiating it with light from a 365 nm ultraviolet LED lamp, and simultaneously cleaving the cleavage group of the material for the interlayer photo-alignment film. The film was then heated at 115°C for 25 seconds to remove the fluorine-containing substituents. This resulted in the formation of a positive C-plate layer with cinnamoyl groups on the outermost surface and a film thickness of 90 nm. The refractive index nI at a wavelength of 550 nm measured using an OPTM interference film thickness meter (manufactured by Otsuka Electronics, analyzed using the least squares method) was 1.57. The Rth(550) at a wavelength of 550 nm measured using an Axoscan (manufactured by Axometrics) was -9 nm.

[0174] Next, the illuminance is 7 mW / cm ２ , irradiation amount 7.9mJ / cm ２ The film was irradiated from the positive C-plate side with polarized UV (wavelength 313 nm). The polarized UV with a wavelength of 313 nm was obtained by passing ultraviolet light emitted from a mercury lamp through a bandpass filter having a transmission band at wavelength 313 nm and a wire grid polarizer. The reflective layer coating solution R-1 prepared above was applied using a wire bar coater and then dried at 110°C for 72 seconds. Thereafter, the film was irradiated with polarized UV light at an illuminance of 80 mW / cm at 100°C in a low-oxygen atmosphere (100 ppm or less). ２ , irradiation amount 500mJ / cm ２ The coating was cured by irradiating it with light from a metal halide lamp (1000 W / m²). The light was irradiated from the cholesteric liquid crystal layer side. The coating thickness was adjusted so that the cured first blue light reflective layer had a thickness of 2.6 μm.

[0175] Next, the first blue light reflecting layer surface was subjected to a discharge of 150 W·min / m ２ After corona treatment, the reflective layer coating solution D-1 was applied to the corona-treated surface using a wire bar coater. Subsequently, the coating film was dried at 70°C for 2 minutes, and after the solvent was evaporated, it was heat-aged at 115°C for 3 minutes to obtain a uniform alignment state. Thereafter, this coating film was kept at 45°C and irradiated with ultraviolet light (300 mJ / cm) using a metal halide lamp under a nitrogen atmosphere. ２) and cured to form a second blue light reflective layer (second light reflective layer) on the first blue light reflective layer. Light irradiation was performed from the cholesteric liquid crystal layer side in all cases. At this time, the coating thickness was adjusted so that the film thickness of the second blue light reflective layer after curing would be 2.0 μm.

[0176] Next, the reflective layer coating solution D-2 was applied onto the second blue light reflective layer using a wire bar coater. Subsequently, the coating film was dried at 70°C for 2 minutes, and after the solvent was evaporated, it was heat-aged at 115°C for 3 minutes to obtain a uniformly oriented state. Thereafter, this coating film was kept at 45°C and irradiated with ultraviolet light (300 mJ / cm) using a metal halide lamp under a nitrogen atmosphere. ２ ) and cured to form a green light reflective layer (third light reflective layer) on the second blue light reflective layer. Light irradiation was performed from the cholesteric liquid crystal layer side in all cases. At this time, the coating thickness was adjusted so that the film thickness of the green light reflective layer after curing was 2.7 μm.

[0177] Next, the reflective layer coating solution R-2 was applied onto the green light reflective layer using a wire bar coater, and then dried at 110°C for 72 seconds. Thereafter, the coating solution was dried in a low-oxygen atmosphere (100 ppm or less) at 100°C with an illuminance of 80 mW and an irradiation dose of 500 mJ / cm. ２ The coating was cured by irradiating it with light from a metal halide lamp at 1000 W / m, thereby forming a red light reflective layer (fourth light reflective layer) on the green light reflective layer. The light irradiation was carried out from the cholesteric liquid crystal layer side in all cases. The coating thickness was adjusted so that the red light reflective layer after curing had a film thickness of 3.4 μm.

[0178] Next, the red light reflecting layer surface was subjected to a discharge of 150 W·min / m ２ After corona treatment at 70°C, the reflective layer coating solution D-3 was applied to the corona-treated surface using a wire bar coater. Subsequently, the coating film was dried at 70°C for 2 minutes, and after the solvent was evaporated, it was heat-aged at 115°C for 3 minutes to obtain a uniform alignment state. Thereafter, this coating film was kept at 45°C and irradiated with ultraviolet light (300 mJ / cm) using a metal halide lamp under a nitrogen atmosphere. ２) and curing to form a yellow light-reflecting layer (fifth light-reflecting layer) on the red light-reflecting layer. Light irradiation was performed from the cholesteric liquid crystal layer side in all cases. At this time, the coating thickness was adjusted so that the film thickness of the yellow light-reflecting layer after curing was 3.4 μm.

[0179] Table 3 shows the central reflection wavelength and film thickness for each reflective layer of the reflective circular polarizer 1 produced. Here, the central reflection wavelength is used to define the characteristics of a light-reflecting film having a reflection band using cholesteric liquid crystal, and refers to the midpoint of the spectral band reflected by the film. Specifically, it was obtained by calculating the average value of the wavelengths on the short wavelength side and the long wavelength side that show half-value of the peak reflectance. The central reflection wavelength (central wavelength of reflected light) was confirmed by creating a film coated with only a single layer. The film thickness was confirmed using an SEM.

[0180] Table 3. Properties of the light-reflecting layer of the reflective circular polarizer

[0181] [Preparation of Reflective Circular Polarizers 2 to 5 and 7 to 15] Reflective circular polarizers 2 to 5 and 7 to 15 were prepared by the same preparation method as reflective circular polarizer 1, except that the film thickness of the light interference layer was changed as shown in Table 4 below. Furthermore, reflective circular polarizer 6 was prepared without a light interference layer by preparing a reflective layer on a rubbed PET film under the same conditions as reflective circular polarizer 1.

[0182] [Fabrication of Reflective Circular Polarizer 16] The reflective circular polarizer 16 was fabricated in the same manner as the reflective circular polarizer 1, except that a photo-alignment layer was formed as the optical interference layer by the following process.

[0183] <Formation of Photo-Alignment Layer>

[0184] The coating solution PA2 for forming an alignment layer, which will be described later, was continuously applied onto a 60 μm-thick tack (triacetyl cellulose) film (TG60, manufactured by Fujifilm Corporation) using a wire bar. The support on which the coating film was formed was dried with hot air at 140° C. for 120 seconds, and then the coating film was irradiated with polarized ultraviolet light (10 mJ / cm ２ A photo-alignment layer having a thickness of 80 nm was formed by irradiating the substrate with light (using an ultra-high pressure mercury lamp).

[0185] ------------------------------------------------------------------ (Coating liquid PA2 for forming alignment layer) ------------------------------------------------------------------ Polymer M-PA-1 (shown below) 100.00 parts by mass Acid generator PAG-1 (shown below) 5.00 parts by mass Acid generator CPI-110TF (shown below) 0.005 parts by mass Xylene 3660.00 parts by mass Methyl isobutyl ketone 366.00 parts by mass

[0186] Polymer M-PA-1

[0187] Acid generator PAG-1

[0188] Acid generator CPI-110TF

[0189] [Fabrication of Reflective Circular Polarizer 17] [Preparation of Coating Solution R-3 for Reflective Layer] The composition shown below was stirred and dissolved in a container kept at 70° C. to prepare Coating Solution R-3 for Reflective Layer, where R represents a coating solution using a rod-like liquid crystal compound.

[0190] -------------------------------------------------- Reflective layer coating liquid R-3 -------------------------------------------------- Methyl ethyl ketone 120.9 parts by mass Cyclohexanone 21.3 parts by mass Rod-like liquid crystal compound X2 below 100.0 parts by mass Photopolymerization initiator B above 1.00 part by mass Chiral agent A above 4.18 parts by mass Surfactant F1 above 0.1 part by mass

[0191] Rod-shaped liquid crystal compound X2

[0192] [Reflective Layer Coating Solution R-4] Reflective layer coating solution R-4 was prepared in the same manner as reflective layer coating solution R-3, except that the amount of chiral agent A added was changed as shown in Table 4 below.

[0193] [Reflective Layer Coating Solution D-4] The following composition was stirred and dissolved to prepare Reflective Layer Coating Solution D-4, where D represents a coating solution using a discotic liquid crystal compound.

[0194] -------------------------------------------------- Reflective layer coating liquid D-4 -------------------------------------------------- 100 parts by mass of the following discotic liquid crystal compound (C) 10 parts by mass of the above polymerizable monomer E1 0.3 parts by mass of the above surfactant F2 3 parts by mass of photopolymerization initiator (Irgacure 907, manufactured by BASF) 5.45 parts by mass of the above chiral agent A 340 parts by mass of methylene chloride --------------------------------------------------

[0195] Discotic Liquid Crystal Compound (C)

[0196] [Reflective layer coating solution D-5 and reflective layer coating solution D-6] Reflective layer coating solution D-5 and reflective layer coating solution D-6 were prepared in the same manner as reflective layer coating solution D-4, except that the amount of chiral agent A added was changed as shown in Table 5 below.

[0197] These coating solutions were used to prepare reflective circular polarizers 17 by coating them onto rubbed PET films in the same manner as for reflective polarizer 6, except that the film thickness after curing was adjusted to the value shown in Table 6.

[0198] The properties of the prepared reflective circular polarizers 1 to 17 are shown in Table 7 below. Table 7. Prepared reflective circular polarizers 1 to 17

[0199] [Preparation of Laminated Optical Films 1 to 16] Laminated optical films were prepared according to the following procedure.

[0200] <Preparation of Retardation Layer 1> A reverse dispersion retardation layer 1 was prepared with reference to the method described in paragraphs 0151 to 0163 of JP 2020-084070 A. The retardation layer 1 had Re(550) = 146 nm and Rth(550) = 73 nm.

[0201] <Preparation of Positive C Plate 2> Positive C Plate 2 was prepared by adjusting the film thickness with reference to the method described in paragraphs 0132 to 0134 of JP 2016-053709 A. However, the support was changed from a polyethylene terephthalate film (PET film) to a triacetyl cellulose film (TAC film). Positive C Plate 2 had an Re(550) of 0.1 nm and an Rth(550) of −80 nm.

[0202] <Preparation of Linear Polarizer> A linear polarizer was prepared by the following procedure.

[0203] (Preparation of Cellulose Acylate Film 1) —Preparation of Core Layer Cellulose Acylate Dope— The following composition was charged into a mixing tank and stirred to dissolve each component, thereby preparing a cellulose acetate solution to be used as the core layer cellulose acylate dope. ----------------------------------- Core Layer Cellulose Acylate Dope --------------------------------------------------- Cellulose acetate having an acetyl substitution degree of 2.88: 100 parts by mass Polyester compound B described in the examples of JP 2015-227955 A: 12 parts by mass Compound F below: 430 parts by mass Methylene chloride (first solvent): 64 parts by mass Methanol (second solvent): 64 parts by mass

[0204] Compound F

[0205] -Preparation of Outer Layer Cellulose Acylate Dope- 10 parts by mass of the following matting agent solution was added to 90 parts by mass of the above core layer cellulose acylate dope to prepare a cellulose acetate solution to be used as the outer layer cellulose acylate dope.

[0206] Matting agent solution - Silica particles with an average particle size of 20 nm (AEROSIL R972, manufactured by Nippon Aerosil Co., Ltd.) 2 parts by mass Methylene chloride (first solvent) 76 parts by mass Methanol (second solvent) 11 parts by mass The above-mentioned cellulose acylate dope for the core layer 1 part by mass

[0207] Preparation of Cellulose Acylate Film 1 The core layer cellulose acylate dope and the outer layer cellulose acylate dope were filtered through a filter paper with an average pore size of 34 μm and a sintered metal filter with an average pore size of 10 μm. The core layer cellulose acylate dope and the outer layer cellulose acylate dope on both sides of the core layer were simultaneously cast onto a drum at 20°C through a casting nozzle (band caster). The film was then peeled off while still containing approximately 20% solvent by weight. Both ends of the film in the width direction were fixed with tenter clips, and the film was stretched transversely at a stretch ratio of 1.1 times while being dried. The film was then transported between the rolls of a heat treatment device and further dried to produce an optical film with a thickness of 40 μm, designated as Cellulose Acylate Film 1. The in-plane retardation of the resulting Cellulose Acylate Film 1 was 0 nm.

[0208] <Formation of Photo-Alignment Layer PA1>

[0209] The coating liquid S-PA-1 for forming an alignment layer, which will be described later, was continuously applied onto the cellulose acylate film 1 using a wire bar. The support on which the coating film was formed was dried with hot air at 140°C for 120 seconds, and then the coating film was irradiated with polarized ultraviolet light (10 mJ / cm ２A photo-alignment layer PA1 was formed by irradiating the substrate with light (using an ultra-high pressure mercury lamp). The film thickness was 0.3 μm.

[0210] ------------------------------------------------------------------ (Coating liquid for forming alignment layer S-PA-1) ------------------------------------------------------------------ Polymer M-PA-1 100.00 parts by mass Acid generator PAG-1 5.00 parts by mass Acid generator CPI-110TF 0.005 parts by mass Xylene 1220.00 parts by mass Methyl isobutyl ketone 122.00 parts by mass

[0211] <Formation of Optically Absorbent Anisotropic Layer P1> The following coating solution SP-1 for forming an optically absorbent anisotropic layer was continuously applied onto the obtained alignment layer PA1 using a wire bar. The coating layer P1 was then heated at 140°C for 30 seconds and cooled to room temperature (23°C). It was then heated at 90°C for 60 seconds and cooled again to room temperature. Thereafter, an LED lamp (center wavelength 365 nm) was used to apply the coating solution SP-1 continuously onto the obtained alignment layer PA1 using a wire bar. The coating layer P1 was then heated at 140°C for 30 seconds and cooled to room temperature (23°C). The coating layer P1 was then heated at 90°C for 60 seconds and cooled again to room temperature. Thereafter, an LED lamp (center wavelength 365 nm) was used to apply the coating solution SP-1 continuously onto the obtained alignment layer PA1 using a wire bar. The coating layer P1 was then heated at 90°C for 60 seconds and cooled again to room temperature. The coating layer P1 was then heated at an illuminance of 200 mW / cm ２ The light was irradiated for 2 seconds under the irradiation conditions of 1.6 μm to form an optically absorptive anisotropic layer P1 on the alignment layer PA1.

[0212] 0.25 parts by mass of dichroic substance D-1 below 0.36 parts by mass of dichroic substance D-2 below 0.59 parts by mass of dichroic substance D-3 below 2.21 parts by mass of polymer liquid crystal compound M-P-1 below 1.36 parts by mass of low molecular weight liquid crystal compound M-1 below 0.200 parts by mass of polymerization initiator IRGACURE OXE-02 (manufactured by BASF) 0.026 parts by mass of surfactant F-3 below Cyclopentanone 46.00 parts by mass Tetrahydrofuran 46.00 parts by mass Benzyl alcohol 3.00 parts by mass ----------------------------------------------------------------------------------

[0213] Dichroic substance D-1

[0214] Dichroic substance D-2

[0215] Dichroic substance D-3

[0216] Polymer liquid crystal compound M-P-1

[0217] Low molecular liquid crystal compound M-1

[0218] Surfactant F-3

[0219] <Transfer for producing laminated optical film> Transfer for producing laminated optical film was performed by the following procedure. (1) UV adhesive Chemiseal U2084B (manufactured by Chemitech Corporation, refractive index after curing n 1.60) was applied to a PMMA substrate to a thickness of 2 μm using a wire bar coater. The optically absorptive anisotropic layer P1 was transferred onto the PMMA substrate. The optically absorptive anisotropic layer P1 was bonded with a laminator so that the side opposite the temporary support of the optically absorptive anisotropic layer P1 was in contact with the UV adhesive. (2) After purging with nitrogen in a purge box until the oxygen concentration was 100 ppm or less, the optically absorptive anisotropic layer P1 was cured by irradiating it with ultraviolet light from a high-pressure mercury lamp from the temporary support side. The illuminance was 25 mW / cm ２ , the irradiation dose is 1000 mJ / cm ２ (3) Finally, the temporary support of the optically absorptive anisotropic layer P1 was peeled off.

[0220] Next, the retardation layer 1 was transferred to the optically absorptive anisotropic layer P1 using the same transfer procedure as described above. However, the retardation layer 1 and the optically absorptive anisotropic layer P1 were laminated so that the slow axis of the retardation layer 1 and the absorption axis of the optically absorptive anisotropic layer P1 formed an angle of 45°. Next, the positive C plate 2 was transferred to the retardation layer 1 using the same transfer procedure as described above. Finally, the reflective circular polarizer 1 was transferred to the positive C plate 2 using the same transfer procedure as described above. In this way, a laminated optical film using the reflective circular polarizer 1 of Example 1 was obtained.

[0221] For the reflective circular polarizers 2 to 16, laminated optical films 2 to 16 were produced in the same manner. For the reflective circular polarizer 17, laminated optical film 23 was produced in the same manner.

[0222] [Preparation of Laminated Optical Film 17] A hard coat layer having a refractive index of 1.57 and a thickness of 90 nm was formed by coating on the surface of the laminated optical film 6 facing the reflective circular polarizer 6, thereby forming an optical interference layer. The Rth(550) of the hard coat layer was 0 nm. The composition of the hard coat layer coating solution and the coating process are shown below.

[0223] ------------------------------------------------------------------ (Coating liquid HC-1 for hard coat layer) ------------------------------------------------------------------ Polymerizable compound 1 12 parts by mass (10-functional urethane acrylate (UV-1700B, manufactured by Nippon Synthetic Chemical Industry)) Polymerizable compound 2 8 parts by mass (Fluorene compound (Oxol EA0200, manufactured by Osaka Gas Chemicals)) Photopolymerization initiator 0.5 parts by mass (Oxime ester type (Irgacure OXE01, manufactured by BASF Japan)) Methyl ethyl ketone 800.00 parts by mass ------------------------------------------------------------------

[0224] The hard coat layer coating solution HC-1 prepared above was applied to the surface of the laminated optical film 6 on the side of the reflective circular polarizer 6 using a wire bar coater, and then dried at 80°C for 60 seconds. Thereafter, the hard coat layer was exposed to light at an irradiation dose of 300 mJ / cm at 78°C in a low-oxygen atmosphere (100 ppm). ２ The polymerizable compound was cured by irradiating it with light from an ultraviolet LED lamp (wavelength 365 nm). This produced a laminated optical film 17 having a 90 nm-thick light interference layer made of a hard coat material on the outermost surface.

[0225] [Preparation of Laminated Optical Films 18 to 22] A light interference layer was formed using the same preparation procedure as for Laminated Optical Film 17. However, the refractive index of the hard coat layer was changed by changing the ratio of polymerizable compound 1 and polymerizable compound 2 in the hard coat layer coating liquid HC-1. A hard coat layer having a refractive index of 1.55 and a thickness of 90 nm was applied to the surface of Laminated Optical Film 6 facing the reflective circular polarizer 6, resulting in Laminated Optical Film 18. Similarly, a hard coat layer having a refractive index of 1.53 and a thickness of 90 nm was formed by a coating method, resulting in Laminated Optical Film 19. Similarly, a hard coat layer having a refractive index of 1.51 and a thickness of 90 nm was formed by a coating method, resulting in Laminated Optical Film 20. Similarly, a hard coat layer having a refractive index of 1.56 and a thickness of 90 nm was formed by a coating method, resulting in Laminated Optical Film 21. Similarly, a hard coat layer having a refractive index of 1.54 and a thickness of 90 nm was formed by a coating method, resulting in Laminated Optical Film 22. All hard coat layers had an Rth(550) of 0 nm.

[0226] [Preparation of Laminated Optical Film 24] Using the same preparation procedure as for laminated optical film 17, a hard coat layer with a refractive index of 1.57 and a thickness of 90 nm was formed by coating on the surface of laminated optical film 23 facing the reflective circular polarizer 17, thereby preparing laminated optical film 24.

[0227] [Molding Method] The prepared laminated optical film was molded into a curved shape. Laminated optical film 1 was set in a molding device. The molding space in the molding device consisted of box 1 and box 2, separated by laminated optical film 1. A convex meniscus lens LE1076-A (diameter 2 inches, focal length 100 mm, radius of curvature of the concave side 65 mm) manufactured by Thorlab, with aluminum vapor deposition on the convex side, was placed in box 1 below laminated optical film 1, with the concave side facing up. The reflective circular polarizer side of laminated optical film 1 was positioned facing the mold. Furthermore, a transparent window was installed on the top of box 2 above laminated optical film 1, and an IR light source for heating laminated optical film 1 was installed outside this window. A patterned infrared reflective filter consisting of a cholesteric liquid crystal layer that reflects infrared light with wavelengths of 2.2 μm to 3.0 μm at a reflectance of approximately 50% was placed between the IR light source and laminated optical film 1. The pattern of the patterned infrared reflection filter was donut-shaped, and was obtained by hollowing out a 1-inch diameter portion in the center of a circular infrared reflection filter with a diameter of 2 inches. When viewed from directly above, the center of the patterned infrared reflection filter was positioned at the center of the mold. Next, a vacuum pump was used to evacuate the interiors of boxes 1 and 2 to 0.1 atmospheres or less. Next, as a step of heating the laminated optical film 1, infrared rays were irradiated to heat the laminated optical film 1 until the center reached 108°C and the edges reached 99°C. Since the glass transition temperature Tg of the PMMA film used as the support was 105°C, the aim was to create a state in which the center was easily stretched and the edges were less likely to stretch during molding. Next, as a step of pressing the laminated optical film 1 against the mold and deforming it to conform to the shape of the mold, gas was flowed into box 2 from a gas cylinder to pressurize it to 300 kPa, and the laminated optical film 1 was pressure-bonded to the mold. Finally, the laminated optical film 1 was removed from the lens mold. As a result, a laminated optical film 1 formed on a curved surface was obtained.

[0228] The laminated optical films 2 to 22 and 24 were also molded into curved surfaces using the same procedure.

[0229] [Evaluation of Ghosting] [Fabrication of Virtual Reality Display Device] A virtual reality display device "Huawei VR Glass" manufactured by Huawei, which is a virtual reality display device employing a reciprocating optical system, was disassembled, and all of the composite lenses were removed. Instead, a composite lens 1 bonded with a laminated optical film 1 was incorporated into the main body, and the laminated optical film 1 was placed between the composite lens 1 and the eye so that the light-absorbing anisotropic layer P1 side was positioned toward the eye, thereby fabricating the virtual reality display device of Example 1. The laminated optical film 1 and the composite lens 1 were bonded using an adhesive (SK2057, manufactured by Soken Chemical & Engineering Co., Ltd.) so that the optical interference layer faced the composite lens 1. This adhesive served as the adhesive layer in the optical laminate of the present invention. At this time, the refractive index nA at a wavelength of 550 nm of the adhesive layer used when attaching the laminated optical film 1 (Example 1) to the lens was 1.49, and the average refractive index nL at a wavelength of 550 nm of the light-reflecting layer (corresponding to the reflective layer A (reflective layer A21a)) was 1.63. The square root of the product of these values ​​((nA × nL) １／２ The refractive index difference between this and the refractive index nI (1.57) of the optical interference layer at a wavelength of 550 nm was 0.01.

[0230] Similarly, laminated optical films 2 to 20 and 24 were also bonded to composite lens 1 and incorporated into the main body of the virtual reality display device to produce the virtual reality display devices of Examples 2 to 13 and 16 and Comparative Examples 1 to 7. Laminated optical films 21 and 22 were similarly bonded to composite lens 1 and incorporated into the main body of the virtual reality display device, except that the adhesive was changed to a pressure-sensitive adhesive (NCF-D692) manufactured by Lintec Corporation, to produce the virtual reality display devices of Examples 14 and 15. Similarly, in Examples 2 to 9, Example 11, Comparative Example 1, and Comparative Examples 3 to 6, the refractive index nI of the optical interference layer at a wavelength of 550 nm was 1.57, and the refractive index difference was 0.01. Furthermore, the refractive index nI of the optical interference layer at a wavelength of 550 nm of Example 10 (reflective polarizer 16) was 1.56, and the refractive index difference was 0.00. Furthermore, the refractive index nI of the optical interference layer at a wavelength of 550 nm of Example 12 was 1.55, and the refractive index difference was 0.01. The refractive index nI of the optical interference layer of Example 13 at a wavelength of 550 nm was 1.53, and the refractive index difference was 0.03. On the other hand, the refractive index nI of the optical interference layer of Comparative Example 7 at a wavelength of 550 nm was 1.51, and the refractive index difference was 0.05. The refractive index nA of the adhesive layer used when attaching the laminated optical film 21 (Example 14) to the lens at a wavelength of 550 nm was 1.46, and the average refractive index nL of the light-reflecting layer (corresponding to reflective layer A (reflective layer A21a)) at a wavelength of 550 nm was 1.63. The square root of the product of these values ​​((nA x nL) １／２ ) was 1.54, and the difference in refractive index from the refractive index nI (1.56) of the optical interference layer at a wavelength of 550 nm was 0.02. The optical interference layer of Example 15 also had a refractive index nI of 1.54 at a wavelength of 550 nm, and the difference in refractive index was 0.00. Furthermore, the refractive index nA of the adhesive layer used when attaching the laminated optical film 24 (Example 16) to the lens at a wavelength of 550 nm was 1.49, and the average refractive index nL of the optical reflective layer (corresponding to reflective layer A (reflective layer A21a)) at a wavelength of 550 nm was 1.66 (Δn was 0.225). The square root of the product of these values ​​((nA x nL) １／２The refractive index difference between the refractive index nI (1.57) of the optical interference layer at a wavelength of 550 nm and the refractive index nI of the optical interference layer at a wavelength of 550 nm was 0.00. The relationship between each example and comparative example and the reflective circular polarizer and laminated optical film used is shown in Table 8 below.

[0231] Here, the refractive index of the adhesive layer was measured using an OPTM interference film thickness meter (manufactured by Otsuka Electronics, analyzed using the least squares method). The average refractive index of the light-reflecting layer was measured using the following method. First, the light-reflecting layer adjacent to the adhesive layer was peeled off and the cross section of the light-reflecting layer was observed using an SEM to obtain the helical pitch P. The helical pitch P is two periods of the light-dark stripe pattern that appears in the SEM image. Next, a reflection spectrum (manufactured by JASCO Corporation, UV-Visible-Near-Infrared Spectrophotometer V-750) was measured to obtain the short-wavelength half-maximum wavelength λl and the long-wavelength half-maximum wavelength λh of the reflection band of the light-reflecting layer. Using the helical pitch P and the half-maximum wavelengths λl and λh, the refractive indices of the light-reflecting layer in two directions, nl = λl / P and nh = λh / P, can be obtained. From this, the average refractive index of the light-reflecting layer, nI = (nl + nh) / 2, was obtained.

[0232] <Evaluation of Ghosts> In the prepared virtual reality display devices, a black and white checkered pattern was displayed on the image display panel, and the ghost visibility was visually evaluated using the following five-point scale. A: Not visible at all. B: Slightly visible, but not bothersome. C: Weak ghost visible. D: Somewhat strong ghost visible. E: Strong ghost visible. The evaluation results are shown in Table 9. As a result, in the virtual reality display devices of Examples 1 to 16, ghosts were either not noticeable or weak across the entire lens area. On the other hand, in the virtual reality display devices of Comparative Examples 1 to 7, light from the white display area was visible as a somewhat strong ghost in part of the black display area of ​​the checkered pattern.

[0233] Table 8. Types of reflective circular polarizers used in Examples and Comparative Examples

[0234] Table 9. Ghost evaluation results

[0235] The present invention can be suitably used in virtual reality display devices, electronic viewfinders, and the like.

[0236] REFERENCE SIGNS LIST 10, 11 Optical laminate 21a, 22a, 23a Reflective layer A 21b, 22b, 24b Reflective layer B 25 First laminated reflective layer 26 Second laminated reflective layer 27 Optical interference layer 28 Adhesive layer 100 Laminated optical film 103 Reflective circular polarizer 104 Positive C plate 105 Retardation layer 106 Linear polarizer 300 Half mirror 400 Circular polarizer 500 Image display panel 1000 Light ray (light ray forming a virtual image) 2000 Light ray (light ray forming a ghost)

Claims

1. An optical laminate having an adhesive layer, a light interference layer, and two or more laminated reflective layers, The laminated reflective layer includes a reflective layer A including at least one cholesteric liquid crystal layer formed using a first liquid crystal compound substantially consisting of a rod-shaped liquid crystal compound, and not including a cholesteric liquid crystal layer formed using a second liquid crystal compound substantially consisting of a discotic liquid crystal compound; a reflective layer B including at least one cholesteric liquid crystal layer formed using the second liquid crystal compound substantially consisting of a discotic liquid crystal compound, and a reflective layer B including no cholesteric liquid crystal layer formed using the first liquid crystal compound substantially consisting of a rod-shaped liquid crystal compound; When the reflective layers A are opposed to each other in two of the two or more laminated reflective layers adjacent to each other in the stacking direction, the central wavelengths of the reflected light of the reflective layers A included in the two adjacent laminated reflective layers are different from each other, When the reflective layers B are opposed to each other in two of the two or more laminated reflective layers adjacent to each other in the stacking direction, the central wavelengths of the reflected light of the reflective layers B included in the two adjacent laminated reflective layers are different from each other, the adhesive layer, the optical interference layer, and the laminated reflective layer are adjacent to each other in this order; When the refractive index of the adhesive layer is nA and the average refractive index of the reflective layer A or the reflective layer B of the laminated reflective layer that is adjacent to the light interference layer is nL, the refractive index nI of the light interference layer is (nA × nL) １／２ −0.03≦nI≦(nA×nL) １／２ +0.03, The optical laminate, wherein the optical interference layer has a film thickness of 60 nm to 110 nm, or 230 nm to 330 nm.

2. The optical laminate according to claim 1 , wherein the reflective layers A and the reflective layers B are alternately arranged in a stacking direction of the optical laminate.

3. The optical laminate according to claim 1 , wherein the total number of layers of the laminated reflective layer is 20 or less.

4. 2. The optical laminate according to claim 1, wherein the reflectance of light having a wavelength of 400 to 700 nm is 40% or more and less than 50%.

5. 2. The optical laminate according to claim 1, wherein the laminated reflective layer is composed of one reflective layer A and one reflective layer B in direct contact with each other, or one reflective layer A, one reflective layer B, and an adhesive layer disposed between the reflective layer A and the reflective layer B.

6. The optical laminate according to claim 1 , wherein the optical interference layer is a photo-alignment film.

7. The optical laminate according to claim 1 , wherein the optical interference layer is a C-plate.

8. The optical laminate according to claim 7 , wherein a compound having a cinnamoyl group is present between the C plate and the laminated reflective layer.

9. The optical laminate according to claim 1 , wherein the optical interference layer is a hard coat layer.

10. The optical laminate according to claim 1, wherein the optical interference film has a thickness of 75 nm to 100 nm, or 245 nm to 300 nm.

11. The optical laminate according to claim 1, wherein the optical interference film has a thickness of 80 nm to 95 nm, or 260 nm to 285 nm.

12. The optical laminate according to claim 7, wherein the thickness direction retardation Rth(550) of the C plate at a wavelength of 550 nm is −30 nm to −5 nm.

13. A laminated optical film having, in this order, at least a reflective circular polarizer, a retardation layer that converts circularly polarized light into linearly polarized light, and a linear polarizer, The reflective circular polarizer is the optical laminate according to any one of claims 1 to 12.

14. The laminated optical film according to claim 13 , wherein the linear polarizer comprises a light-absorbing anisotropic layer containing at least a liquid crystal compound and a dichroic material.

15. The laminated optical film of claim 13 , further comprising a positive C-plate.

16. The laminated optical film according to claim 13 , further comprising an anti-reflection layer on the surface.

17. The laminated optical film according to claim 16 , wherein the antireflection layer is a moth-eye film or an AR film.

18. The laminated optical film according to claim 13 , comprising a resin substrate having a peak temperature of loss tangent tanδ of 170° C. or less.

19. An optical article comprising the optical laminate according to any one of claims 1 to 12.

20. 20. A virtual reality display device comprising the optical article of claim 19.