Optical laminate, optical lens, and virtual reality display device

Abstract

The present invention addresses the problem of providing an optical laminate that includes a reflective polarizer, an absorptive polarizer, and at least one adhesive layer and that exhibits high image sharpness when used as bonded to a lens or the like of a virtual reality display device. An optical laminate according to the present invention includes a reflective polarizer, an absorptive polarizer, and at least one adhesive layer. The reflective polarizer exhibits a shrinkage by a rate greater than or equal to 0% and less than 0.8% along at least one in-plane direction as a dimensional change when heated for one minute at a temperature higher than the glass transition temperature of the reflective polarizer by 20°C. The reflective polarizer is a reflective linear polarizer formed by alternately stacking a plurality of birefringent layers of two or more different kinds.

Description

Optical laminate, optical lens, and virtual reality display device

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

[0002] A reflective polarizer is a polarizer that reflects one polarized light and transmits the other polarized light of incident light. An absorptive polarizer is a polarizer that absorbs one polarized light of incident light and transmits the other polarized light. The light absorbed by an absorptive polarizer and the light transmitted through it are polarized in orthogonal directions.

[0003] As a reflective linear polarizer in which transmitted light and reflected light become linearly polarized light, for example, a film in which two or more different types of birefringent layers are alternately laminated is known, as described in Patent Document 1.

[0004] As a reflective circular polarizer in which transmitted light and reflected light become circularly polarized light, for example, a film having a layer in which a cholesteric liquid crystal phase is fixed, as described in Patent Document 2, is known.

[0005] Reflective polarizers are used to extract only specific polarized light from incident light or to separate incident light into two polarized lights. However, when a reflective polarizer is used alone, the separation of polarized light is often insufficient. Therefore, they are often used as optical laminates including a reflective polarizer and an absorptive polarizer. In addition, reflective polarizers are often further laminated with other functional layers such as retardation plates. Such optical laminates are used, for example, as brightness enhancement films in liquid crystal display devices, which reflect and reuse unwanted polarized light from the backlight to improve light utilization efficiency. They are also used as beam splitters in liquid crystal projectors, which split light from a light source into two linearly polarized lights and supply each to a liquid crystal panel.

[0006] Furthermore, in recent years, a method has been proposed in which an optical laminate including an absorptive polarizer, a reflective polarizer, a λ / 4 retardation plate, etc. is used to separate a portion of external light or light from an image display device into two orthogonal polarized lights, reflect one polarized light, and transmit the other to generate a virtual image and a real image. For example, Patent Document 3 discloses a method for reducing the size or thickness of a display unit in a virtual reality display device, an electronic viewfinder, etc., in which an optical laminate including an absorptive polarizer and a reflective polarizer is used to reflect light back and forth between the reflective polarizer and a half mirror, and then transmit the light through the reflective polarizer and the absorptive polarizer to generate a virtual image.

[0007] JP 2011-053705 A Japanese Patent No. 6277088 A Japanese Patent No. 6501877 A

[0008] According to the inventor's investigations, it has been found that the sharpness of the displayed image may be reduced in the virtual reality display device described in Cited Document 3. In the virtual reality display device, the image displayed by the image display device is magnified and viewed due to the action of an optical laminate including a lens and a reflective polarizer and an absorptive polarizer, and therefore slight irregularities in the optical laminate may distort the image, reducing the sharpness of the image.

[0009] The present invention has been made in view of the above problems, and an object of the present invention is to provide an optical laminate that exhibits high image sharpness when used by being attached to a lens or the like of a virtual reality display device. Another object of the present invention is to provide an optical lens and a virtual reality display device.

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

[0011] [1] An optical laminate including a reflective polarizer, an absorptive polarizer, and an adhesive layer, wherein the reflective polarizer shrinks by 0% or more and less than 0.8% in dimension in at least one in-plane direction when heated for 1 minute at a temperature 20°C higher than the glass transition temperature of the reflective polarizer, and the reflective polarizer is a reflective linear polarizer formed by alternatingly stacking two or more different birefringent layers. [2] The optical laminate according to [1], wherein the absorptive polarizer has an anisotropic absorbing layer containing at least a liquid crystalline compound and a dichroic dye. [3] The optical laminate according to [1] or [2], wherein at least one of the adhesive layers is a layer made of a pressure-sensitive adhesive sheet, and the pressure-sensitive adhesive sheet has a storage modulus G' of 0.8 MPa or more at 20°C as measured by a torsional shear method. [4] The optical laminate according to any one of [1] to [3], wherein at least one of the adhesive layers is a layer formed by curing an adhesive layer-forming composition containing an ultraviolet-curable adhesive. [5] The optical laminate according to any one of [1] to [4], further comprising at least one λ / 4 retardation plate. [6] The optical laminate according to [5], wherein the λ / 4 retardation plate has a fixed liquid crystal phase. [7] An optical lens having a curved surface portion, wherein the optical laminate according to any one of [1] to [6] is bonded to the curved surface portion. [8] A virtual reality display device comprising an image display device that emits polarized light, a half mirror having a curved surface portion, and the optical lens according to [7].

[0012] According to the present invention, an optical laminate that exhibits high image sharpness when used by being attached to a lens or the like of a virtual reality display device can be provided. Furthermore, according to the present invention, an optical lens and a virtual reality display device can be provided.

[0013] 1 is an example of a virtual reality display device using the optical laminate of the present invention.

[0014] The present invention will be described in detail below with reference to the drawings. The following description of the components may be based on representative embodiments or 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 strictly 90°, but means 90°±10°, preferably 90°±5°. "Parallel" does not mean strictly 0°, but means 0°±10°, preferably 0°±5°. "45°" does not mean strictly 45°, but means 45°±10°, preferably 45°±5°.

[0016] As used herein, the term "absorption axis" refers to the polarization direction in which absorbance is maximized in a plane when linearly polarized light is incident. The term "reflection axis" refers to the polarization direction in which reflectance is maximized in a plane when linearly polarized light is incident. The term "transmission axis" refers to the direction perpendicular to the absorption axis or reflection axis in a plane. The term "slow axis" refers to the direction in which refractive index is maximized in a plane. As used herein, "mutually orthogonal polarization states" refers to polarization states located at antipodes on the Poincaré sphere, such as linearly polarized light that is orthogonal to each other. While right-handed circularly polarized light and left-handed circularly polarized light are not generally referred to as "mutually orthogonal polarization states," in the definition herein, right-handed circularly polarized light and left-handed circularly polarized light are also interpreted as being in mutually orthogonal polarization states.

[0017] In this specification, unless otherwise specified, phase difference means 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). 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 following slow axis direction (°) can be calculated: Re(λ) = R0(λ) Rth(λ) = ((nx + ny) / 2 - nz) × d

[0018] [Optical Laminate] The optical laminate of the present invention includes a reflective polarizer, an absorptive polarizer, and at least one adhesive layer, and the reflective polarizer exhibits a dimensional change of 0% or more and less than 0.8% shrinkage when heated for 1 minute at a temperature 20°C higher than the glass transition temperature of the reflective polarizer in at least one in-plane direction. The reflective polarizer is a reflective linear polarizer formed by alternately stacking two or more different birefringent layers.

[0019] Here, a method for measuring the glass transition temperature of a reflective polarizer will be described. Using a dynamic viscoelasticity measuring device (DVA-200 manufactured by IT Measurement Control Co., Ltd.), E" (loss modulus) and E' (storage modulus) are measured under the following conditions for a film sample (reflective polarizer) that has been conditioned in advance in an atmosphere at a temperature of 25°C and a humidity of 60% Rh for at least two hours, and tan δ (= E" / E') is calculated. 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 to 220°C Heating conditions: 5°C / min Frequency: 1 Hz The peak temperature of the obtained tan δ is the glass transition temperature.

[0020] The optical laminate of the present invention can exhibit high image sharpness when used by being bonded to a lens or the like of a virtual reality display device. As a suitable example of use, the use in a virtual reality display device will be taken up and the action of the optical laminate of the present invention will be described in detail. Hereinafter, the ability of the optical laminate to exhibit high image sharpness when used by being bonded to a lens or the like of a virtual reality display device will also be referred to as "excellent image sharpness."

[0021] FIG. 1 shows a virtual reality display device using the optical laminate of the present invention. As shown in FIG. 1, a light ray 1000 emitted from an image display panel 500 passes through a circular polarizer 400 to become circularly polarized light, and then passes through a half mirror 300. The light ray then enters the optical laminate 100 of the present invention from the reflective polarizer side, is totally reflected, is reflected again by the half mirror 300, and again enters the optical laminate 100. At this time, the light ray 1000 has been reflected by the half mirror, becoming circularly polarized light that is orthogonal to the circularly polarized light that entered the optical laminate 100 the first time. Therefore, the light ray 1000 passes through the optical laminate 100 and is visually recognized by the user. Furthermore, when the light ray 1000 is reflected by the half mirror 300, the image is magnified due to the half mirror's concave mirror shape, allowing the user to visually recognize the magnified virtual image. The above-described mechanism is called a reciprocating optical system or a folded optical system.

[0022] A virtual reality display device using an optical laminate displays an enlarged image using a reciprocating optical system, but if the optical laminate has irregularities, the light rays will bend in a direction other than the specified direction, reducing the image sharpness. Therefore, in order to improve the image sharpness when the optical laminate is used in a virtual reality display device, it is preferable that the optical laminate has few irregularities and high smoothness.

[0023] Various sensors using near-infrared light as a light source for eye tracking, facial expression recognition, iris authentication, etc. may be incorporated into optical systems such as virtual reality display devices and electronic viewfinders. In order to minimize the influence on such sensors, the optical laminate of the present invention is preferably transparent to near-infrared light.

[0024] [Reflective Polarizer] The optical laminate of the present invention includes at least a reflective linear polarizer as a reflective polarizer, which is formed by alternately stacking two or more different birefringent layers and whose dimensional change upon heating is 0% or more and less than 0.8%. In this specification, the term "shrinkage of 0% or more and less than 0.8%" also applies to a case where the dimensional change upon heating for 1 minute at a temperature 20°C higher than the glass transition temperature of the reflective polarizer is 0%, i.e., a case where the dimensional change of the reflective polarizer upon heating is 0%.

[0025] A reflective linear polarizer is a polarizer that transmits linearly polarized light in a certain direction and reflects linearly polarized light in a direction perpendicular to the linearly polarized light. Examples of reflective linear polarizers include films obtained by stretching a dielectric multilayer film in which two or more different birefringent layers are alternately stacked, as described in JP 2011-053705 A and M.F. Weber, C.A. Stover, L.R. Gilbert, T.J. Nevitt and A.J. Ouderkirk, Science 287(5462), 2451-2456 (2000). Commercially available reflective linear polarizers can also be used. Commercially available reflective linear polarizers include a reflective polarizer (product name APF) manufactured by 3M.

[0026] The reflective polarizer used in the optical laminate of the present invention exhibits a dimensional change of 0% or more but less than 0.8% in at least one in-plane direction when heated for 1 minute at a temperature 20°C higher than the glass transition temperature of the reflective polarizer. Whether the dimensional change of the reflective polarizer is shrinkage or expansion is confirmed by measuring the dimensions of the reflective polarizer before and after heating. When the dimensional change of the reflective polarizer is shrinkage, i.e., when the dimensions after heating are smaller than the dimensions before heating, the dimensional change indicating the degree of shrinkage due to heating is calculated from the measured dimensions before and after heating using the following formula: Dimensional change of reflective polarizer = {(dimension of reflective polarizer before heating) - (dimension of reflective polarizer after heating)} / (dimension of reflective polarizer before heating) x 100.

[0027] Although the details of the mechanism by which high image sharpness is achieved when the optical laminate of the present invention is bonded to a lens or the like of a virtual reality display device and used is unknown, the following speculation can be made. When the optical laminate is bonded to a lens or the like, it may be heated to improve adhesion. In particular, when the lens has a curved surface, the optical laminate is often heated to a temperature higher than the glass transition temperature of the reflective polarizer in order to mold the optical laminate into a curved shape. If the reflective polarizer expands due to heating, an absorptive polarizer or the like bonded to the reflective polarizer may break, and the smoothness of the optical laminate after being bonded to the lens may be significantly impaired. Furthermore, after being bonded to a lens or the like, the optical laminate may be heated for the purpose of a heat resistance test or the like. If the reflective polarizer expands at this time, the smoothness of the optical laminate may be impaired. In contrast, the dimensional change of the reflective polarizer included in the optical laminate of the present invention when heated for 1 minute at a temperature 20° C. higher than the glass transition temperature is contraction. Therefore, it is thought that expansion and breakage due to the heat treatment when bonding to a lens or the like can be prevented, and the smoothness of the optical laminate can be maintained. On the other hand, if the shrinkage rate of the reflective polarizer is 0.8% or more, when the optical laminate is bonded to a lens or the like, the dimensional change of the optical laminate is large, making it difficult to bond the optical laminate in the desired shape. Furthermore, after being bonded to a lens or the like, the dimensional change of the optical laminate is large, and the optical laminate may peel off from the lens or the like when a heat resistance test is performed. In contrast, the reflective polarizer contained in the optical laminate of the present invention has a shrinkage rate of less than 0.8% when heated for 1 minute at a temperature 20°C higher than the glass transition temperature. This allows the optical laminate to be easily bonded to a lens or the like in the desired shape, and also suppresses dimensional change of the optical laminate during a heat resistance test, preventing peeling of the optical laminate. It is therefore presumed that high image sharpness can be achieved when the optical laminate of the present invention is bonded to a lens or the like of a virtual reality display device.

[0028] The reflective polarizer included in the optical laminate of the present invention preferably experiences a dimensional change due to heating in at least one in-plane direction of shrinkage of more than 0% and less than 0.5%, more preferably more than 0% and less than 0.4%, and even more preferably more than 0% and less than 0.1%. Furthermore, the reflective polarizer preferably experiences a dimensional change due to heating in all in-plane directions of shrinkage of 0% or more and less than 0.8%, more preferably more than 0% and less than 0.5%, even more preferably more than 0% and less than 0.4%, and particularly preferably more than 0% and less than 0.1%.

[0029] The glass transition temperature of the reflective polarizer is, for example, 80° C. or higher, and from the viewpoint of excellent durability, is preferably 90° C. or higher, and more preferably 95° C. or higher. The upper limit is not particularly limited, but is preferably 150° C. or lower.

[0030] The method for preparing the reflective polarizer included in the optical laminate is not particularly limited. For example, a known reflective linear polarizer or a commercially available reflective linear polarizer that shrinks by 0.8% or more when heated for 1 minute at a temperature 20°C higher than the glass transition temperature can be obtained. The obtained reflective polarizer is then heated and subjected to a preheating treatment to shrink it before being bonded to an absorptive polarizer, thereby producing a reflective polarizer with a dimensional change of 0% or more and less than 0.8% upon heating. Furthermore, a reflective polarizer with a dimensional change of 0% or more and less than 0.8% upon heating can also be produced by adjusting the stretching ratio when stretching the dielectric multilayer film during the production process of a known reflective linear polarizer. The conditions for the preheating treatment are not particularly limited and may be appropriately adjusted depending on the reflective polarizer being used. The heating temperature for the preheating treatment is preferably 10 to 50°C higher than the glass transition temperature of the reflective polarizer. The preheating treatment time is preferably 1 to 10 minutes. The preheating treatment can be performed using a known heating means such as an oven.

[0031] Instead of the reflective linear polarizer contained in the optical laminate of the present invention, an optical laminate containing a reflective polarizer other than the reflective linear polarizer (hereinafter also referred to as "another reflective polarizer") in which the dimensional change when heated for 1 minute at a temperature 20°C higher than the glass transition temperature of the reflective polarizer is 0% or more and less than 0.8%, and in which two or more different birefringent layers are alternately stacked, also has excellent image sharpness.

[0032] Other examples of reflective polarizers include wire-grid polarizers as described in JP 2015-028656 A and the like. Commercially available wire-grid polarizers can also be suitably used. Examples of commercially available wire-grid polarizers include a wire-grid polarizer (product name WGF) manufactured by AGC.

[0033] Another example of a reflective polarizer is a reflective circular polarizer. A reflective circular polarizer is a polarizer that transmits right-handed or left-handed circularly polarized light and reflects circularly polarized light with the opposite rotation direction to the transmitted circularly polarized light. An example of a reflective circular polarizer is a reflective circular polarizer having a cholesteric liquid crystal layer. The cholesteric liquid crystal layer is a liquid crystal layer formed by fixing a cholesterically oriented liquid crystal phase (cholesteric liquid crystal phase).

[0034] As is well known, a cholesteric liquid crystal layer has a helical structure in which liquid crystal compounds are spirally rotated and stacked, and the liquid crystal compounds are stacked in a spiral shape with one helical pitch (360° rotation) being defined as one helical pitch (helical pitch). The cholesteric liquid crystal layer reflects right-handed or left-handed circularly polarized light in a specific wavelength range and transmits other light depending on the length of the helical pitch and the helical rotation direction (sense) of the liquid crystal compounds. Therefore, in order to reflect wavelengths across the entire visible range, the reflective circular polarizer may have multiple cholesteric liquid crystal layers, such as a cholesteric liquid crystal layer having a central wavelength that selectively reflects red light, a cholesteric liquid crystal layer having a central wavelength that selectively reflects green light, and a cholesteric liquid crystal layer having a central wavelength that selectively reflects blue light.

[0035] The other reflective polarizer exhibits a dimensional change of 0% or more and less than 0.8% shrinkage in at least one in-plane direction when heated for 1 minute at a temperature 20° C. higher than the glass transition temperature of the reflective polarizer. The dimensional change and manufacturing method of the other reflective polarizer, including their preferred ranges, may be the same as those of the above-mentioned reflective linear polarizer formed by alternately stacking two or more types of birefringent layers.

[0036] [Absorptive Polarizer] The optical laminate of the present invention includes at least an absorptive polarizer. The absorptive polarizer used in the optical laminate of the present invention absorbs linearly polarized light in the absorption axis direction of incident light and transmits linearly polarized light in the transmission axis direction. The single-plate transmittance of the absorptive 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 absorptive polarizer are measured using an automatic polarizing film measuring device: VAP-7070 (manufactured by JASCO Corporation). In the optical laminate, the absorptive polarizer is preferably arranged so that the orientation of the absorption axis of the absorptive polarizer is parallel to the orientation of the reflection axis of the reflective polarizer.

[0037] The absorptive polarizer used in the optical laminate of the present invention preferably has an anisotropic absorbing layer containing at least a liquid crystalline compound and a dichroic dye. This is because an anisotropic absorbing layer containing a liquid crystalline compound and a dichroic dye can be thinned and is less likely to crack or break even when stretched or molded. The thickness of the anisotropic absorbing 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. An absorptive polarizer containing a liquid crystalline compound and a dichroic dye can be produced, for example, with reference to JP 2020-023153 A. From the viewpoint of improving the polarization degree of the absorptive polarizer, the anisotropic absorbing layer preferably has a degree of orientation of the dichroic dye of 0.95 or more, more preferably 0.97 or more.

[0038] The absorptive polarizer may include layers other than the anisotropic absorbing layer, such as a support, an alignment layer, and a protective layer. The alignment layer is used to align the liquid crystalline compound contained in the anisotropic absorbing layer in a specific direction. The alignment layer is not particularly limited, but a layer obtained by rubbing a layer containing polyvinyl alcohol or a photo-alignment film can be used. The protective layer can be provided by coating on the anisotropic absorbing layer. The composition of the protective layer is not particularly limited, but a layer containing polyvinyl alcohol is preferred from the viewpoint of improving the durability of the anisotropic absorbing layer. The type of support is not particularly limited, but a transparent support is preferred. For example, a film made of cellulose acylate, polycarbonate, polysulfone, polyethersulfone, polyacrylate and polymethacrylate, cyclic polyolefin, polyolefin, polyamide, polystyrene, or polyester can be used. Among these, a cellulose acylate film, a cyclic polyolefin film, a polyacrylate film, or a polymethacrylate film is preferred. Alternatively, commercially available cellulose acylate films (for example, "TD80U" and "Z-TAC" manufactured by Fujifilm Corporation) can also be used. Furthermore, the support preferably has a small retardation in order to suppress adverse effects on the polarization degree of transmitted light and reflected light. Specifically, the Re value is preferably 10 nm or less, and the absolute value of the Rth value is preferably 50 nm or less.

[0039] Alternatively, the absorptive polarizer may be provided as a transfer film coated with a layer including an anisotropic absorbing layer on a temporary support, and then formed by transferring the anisotropic absorbing layer to produce another laminate, followed by peeling and removing the temporary support. Removing the temporary support allows the optical laminate to be made thinner and also eliminates the adverse effect of the retardation of the temporary support on the polarization degree of transmitted light and reflected light. To prevent breakage during peeling, the temporary support is preferably a support with high tear strength. Polycarbonate or polyester films are preferred as temporary supports. Furthermore, in the manufacturing process of the optical laminate, it is preferable that the retardation of the temporary support be small in order to perform quality inspections of the anisotropic absorbing layer and other laminates. When the absorptive polarizer is provided as a transfer film coated with a layer including an anisotropic absorbing layer on a temporary support, it is preferable that the absorptive polarizer be provided in a form in which a protective film is laminated to prevent the layer including the anisotropic absorbing layer from peeling off and becoming a foreign substance during film transport or during a slitting process before lamination.

[0040] [Adhesive Layer] The optical laminate of the present invention includes at least one adhesive layer. The optical laminate of the present invention is a laminate including multiple functional layers including a reflective polarizer and an absorptive polarizer. It is preferable that each functional layer of the optical laminate is bonded via an adhesive layer. The adhesive layer can be formed using, for example, an adhesive or a pressure-sensitive adhesive. Any commercially available adhesive can be used as the adhesive. More specifically, epoxy resin-based adhesives and acrylic resin-based adhesives can be used as the adhesive. Any commercially available pressure-sensitive adhesive can be used as the pressure-sensitive adhesive, and a pressure-sensitive adhesive that does not easily outgas is preferred. In particular, when stretching or molding the optical laminate, a vacuum process or a heating process may be performed. It is preferable that no outgassing is generated from the adhesive layer even under the conditions of these vacuum processes or heating processes.

[0041] From the viewpoint of improving the smoothness of the optical laminate and improving the sharpness of images in a virtual reality display device or the like using the optical laminate, the thickness of the adhesive layer is preferably 15 μm or less, more preferably 10 μm or less, and even more preferably 6 μm or less. There is no particular restriction on the lower limit of the thickness of the adhesive layer, but from the viewpoint of burying foreign matter present inside the optical laminate and smoothing it, the thickness is preferably 0.5 μm or more, and more preferably 1 μm or more.

[0042] <Adhesive> The adhesive layer can be formed, for example, by irradiating an adhesive layer-forming composition containing a UV-curable adhesive with UV light to cure it. It is preferable that at least one of the adhesive layers included in the optical laminate is a layer formed by curing an adhesive layer-forming composition containing a UV-curable adhesive. Known adhesives can be used as the UV-curable adhesive. The type of adhesive layer-forming composition is not particularly limited, but from the viewpoint of improving adhesive strength with the functional layer, it is preferable that it contains a compound containing a (meth)acryloyl group, and it is also preferable that it contains a boronic acid compound. From the viewpoint of achieving a uniform coating thickness, the viscosity of the adhesive layer-forming composition is preferably 10 cP or more and 500 cP or less, more preferably 50 cP or more and 400 cP or less, and even more preferably 100 cP or more and 350 cP or less.

[0043] The adhesive layer can also be formed by laminating a sheet containing an adhesive layer-forming composition including a UV-curable adhesive to one adherend, laminating the other adherend to the sheet, and then curing the laminate by irradiating it with UV light. The adhesive strength of the adhesive layer can be further improved by irradiating it with UV light and curing the laminate after laminating the adherend. Furthermore, when stretching or molding the optical laminate, outgassing during a vacuum process or heating process can be suppressed.

[0044] <Pressure-sensitive adhesive> The adhesive layer can also be formed by laminating a pressure-sensitive adhesive sheet. Preferably, at least one of the adhesive layers included in the optical laminate is a layer made of a pressure-sensitive adhesive sheet. The type of pressure-sensitive adhesive sheet is not limited, and from the viewpoint of improving the smoothness of the optical laminate, the storage modulus G' measured by a torsional shear method at 20°C is preferably 0.8 MPa or more, more preferably 1.5 MPa or more, and even more preferably 2.0 MPa or more. There is no particular limit to the upper limit, but it is preferably 30 MPa or less. The storage modulus G' of the pressure-sensitive adhesive sheet measured by the torsional shear method can be measured using a viscoelasticity measuring device such as "HAAKE MARS" manufactured by Thermo Fisher Scientific, for example. When a commercially available pressure-sensitive adhesive sheet is used, the storage modulus G' may be a catalog value.

[0045] [λ / 4 Retardation Plate] The optical laminate of the present invention may further include at least one λ / 4 retardation plate. In this specification, the λ / 4 retardation plate refers to a retardation plate having an in-plane retardation (Re) of approximately ¼ wavelength at any wavelength of visible light. The λ / 4 retardation plate has the function of converting circularly polarized light into linearly polarized light and converting linearly polarized light into circularly polarized light. Therefore, by laminating a λ / 4 retardation plate and an absorptive polarizer so that the orientation of the slow axis of the λ / 4 retardation plate is at 45° with the orientation of the absorption axis of the absorptive polarizer, an optical laminate that can be used as an absorptive circular polarizer can be obtained. Furthermore, by laminating a λ / 4 retardation plate and a reflective linear polarizer so that the orientation of the slow axis of the λ / 4 retardation plate is at 45° with the orientation of the transmission axis of the reflective linear polarizer, an optical laminate that can be used as a reflective circular polarizer can be obtained. Furthermore, by laminating a λ / 4 retardation plate and a reflective circular polarizer at an arbitrary angle, an optical laminate that can be used as a reflective linear polarizer can be obtained.

[0046] As the λ / 4 retardation plate, a λ / 4 retardation plate having an Re of 120 to 150 nm at a wavelength of 550 nm is preferred, a λ / 4 retardation plate having an Re of 130 to 150 nm is more preferred, and a λ / 4 retardation plate having an Re of 130 to 140 nm is even more preferred. Furthermore, a retardation plate having an Re of approximately ¾ wavelength or approximately ¾ wavelength can also be used in the same way as a λ / 4 retardation plate, since it can convert linearly polarized light into circularly polarized light.

[0047] Furthermore, it is preferable that the λ / 4 retarder has reverse dispersion with respect to wavelength. This is because reverse dispersion 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 retarder 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. Furthermore, a retarder having reverse dispersion may be produced as long as it has substantially reverse dispersion. For example, as disclosed in Japanese Patent No. 6259925 A, it can also be produced by laminating a retarder having an Re of approximately ¼ wavelength and a retarder having an Re of approximately ½ wavelength so that their slow axes form an angle of approximately 60°. In this case, it is known that even if the quarter-wave retardation plate and the half-wave retardation plate each have normal dispersion (the retardation value at the wavelength decreases as the wavelength increases), they can convert circularly polarized light 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 optical laminate has a reflective circular polarizer, a quarter-wave retardation plate, a half-wave retardation plate, and a linear polarizer in this order.

[0048] In addition, the optical laminate preferably has a layer formed by fixing a uniformly aligned liquid crystal compound as a retardation plate. 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 2020-084070 A, a retardation plate having reverse dispersion can also be produced by uniformly aligning and fixing a rod-shaped liquid crystal compound having reverse dispersion.

[0049] In addition, the optical laminate also preferably has a layer that is made by fixing the liquid crystal compound that is twisted and aligned with thickness direction as helical axis as retardation plate.For example, as disclosed in Japanese Patent No. 5753922 and Japanese Patent No. 5960743, a retardation plate that has a layer that is made by fixing the rod-shaped liquid crystal compound or discotic liquid crystal compound that is twisted and aligned with thickness direction as helical axis as retardation plate can also be used, and in this case, the retardation plate can be regarded as having substantially reverse dispersion, so it is preferable.

[0050] The thickness of the λ / 4 retarder is not particularly limited, but is preferably 0.1 to 8 μm, more preferably 0.3 to 5 μm, from the viewpoint of thinning. Also, from the viewpoint of thinning, a λ / 4 retarder in which a liquid crystal phase is fixed is preferred.

[0051] The λ / 4 retardation plate may include a support, an alignment layer, a retardation plate, and the like. The type of support is not particularly limited, but is preferably transparent. 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 film, or polyacrylate or polymethacrylate film are preferred. Commercially available cellulose acylate films (e.g., "TD80U" and "Z-TAC" manufactured by Fujifilm Corporation) can also be used. Furthermore, the support preferably has a small retardation in order to suppress adverse effects on the polarization degree of transmitted light and reflected light. Specifically, the Re value is preferably 10 nm or less, and the absolute value of the Rth value is preferably 50 nm or less.

[0052] Alternatively, the λ / 4 retardation plate may be supplied as a transfer film in which a layer including a retardation layer is coated on a temporary support, and then formed by transferring the retardation layer to another laminate and then peeling and removing the temporary support. Removing the temporary support is preferable because it allows the optical laminate to be made thinner and also eliminates the adverse effect of the retardation of the temporary support on the polarization degree of transmitted light and reflected light. The temporary support is preferably a support with high tear strength in order to prevent breakage during peeling. Polycarbonate or polyester films are preferred as the temporary support. Furthermore, in the manufacturing process of the optical laminate, it is preferable that the retardation of the temporary support is small in order to perform quality inspections of the anisotropic absorbing layer and other laminates.

[0053] [Other Functional Layers] The optical laminate may have other functional layers.

[0054] <Positive C Plate> The optical laminate 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 method for producing 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 for increasing the degree of polarization of transmitted light and reflected light with respect to obliquely incident light. The positive C plate can be disposed at any position in the optical laminate, and multiple positive C plates may be disposed.

[0055] The positive C plate may be disposed adjacent to the reflective circular polarizer or inside the reflective circular polarizer. For example, when a light-reflecting layer formed by fixing a cholesteric liquid crystal phase containing a rod-shaped liquid crystal compound is used as the reflective circular polarizer, the light-reflecting 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 the transmitted light, resulting in a decrease in the degree of polarization of the reflected light and the transmitted light. Having a positive C plate inside or near the reflective circular polarizer 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 reflected light and the transmitted light.

[0056] The positive C plate may be disposed adjacent to or inside the λ / 4 retardation plate. For example, when a layer formed by immobilizing a rod-shaped liquid crystal compound is used as the λ / 4 retardation plate, the λ / 4 retardation plate has a positive Rth. In this case, when light is incident on the λ / 4 retardation plate from an oblique direction, the Rth may change the polarization state of the transmitted light, potentially reducing the degree of polarization of the transmitted light. Having a positive C plate inside or near the λ / 4 retardation plate is preferable because it can suppress changes in the polarization state of obliquely incident light and reduce the degree of polarization of the transmitted light. The positive C plate is preferably disposed on the side of the λ / 4 retardation plate opposite the absorptive polarizer, but may be disposed elsewhere. In this case, the Re of the positive C plate is preferably approximately 10 nm or less, and the Rth is preferably −90 to −40 nm.

[0057] <Anti-Reflection Layer> The optical laminate preferably has an anti-reflection layer on its surface. The optical laminate of the present invention has the function of reflecting specific polarized light and transmitting polarized light perpendicular to the specific polarized light. However, reflection on the surface of the optical laminate generally includes reflection of unintended polarized light, thereby reducing the polarization degree of transmitted and reflected light. Therefore, it is preferable that the optical laminate has an anti-reflection layer on its surface. The anti-reflection layer may be disposed on only one surface of the optical laminate or on both surfaces. The type of anti-reflection layer is not particularly limited, but a moth-eye film or an AR film is preferred from the viewpoint of further reducing the reflectance. Furthermore, when the optical laminate is stretched or molded, a moth-eye film is preferred because it can maintain high anti-reflection performance even if the film thickness changes due to stretching. Furthermore, when the anti-reflection layer includes a support and stretching or molding is performed, the support preferably has a Tg peak temperature of 170°C or less, more preferably 130°C or less, from the viewpoint of facilitating stretching or molding. Specifically, a PMMA film or the like is preferred.

[0058] <Second λ / 4 Retardation Plate> The optical laminate preferably further includes a second λ / 4 retardation plate. The optical laminate may include, for example, a reflective circular polarizer, a λ / 4 retardation plate, an absorbing polarizer, and a second λ / 4 retardation plate in this order. Light incident on the optical laminate from the reflective polarizer side and transmitted through the absorbing polarizer is linearly polarized light, a portion of which is reflected by the outermost surface on the absorbing polarizer side and then exits again from the surface on the reflective polarizer side. Such light is unnecessary reflected light and may cause a decrease in the degree of polarization of the reflected light, so it is preferable to reduce it. One method of suppressing reflection on the outermost surface on the absorbing polarizer side is to laminate an antireflection layer. However, when the optical laminate is used by being bonded to a medium such as glass or plastic, even if an antireflection layer is provided on the bonding surface of the optical laminate, reflection on the surface of the medium cannot be suppressed, and therefore, an antireflection effect cannot be obtained. On the other hand, when a second λ / 4 retardation plate that converts linearly polarized light into circularly polarized light is installed, the light that reaches the outermost surface on the absorptive polarizer side becomes circularly polarized light and is converted into orthogonal circularly polarized light when reflected by the outermost surface of the medium. After that, when the light passes through the second λ / 4 retardation plate again and reaches the absorptive polarizer, it becomes linearly polarized light in the absorption axis direction of the absorptive polarizer and is absorbed. Therefore, unnecessary reflection can be prevented. From the viewpoint of more effectively suppressing unnecessary reflection, it is preferable that the second λ / 4 retardation plate has substantially reverse dispersion.

[0059] <Support> The optical laminate of the present invention may further include a support. The support can be placed in any location. The type of support is not particularly limited, but is preferably transparent. 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 film, polyacrylate film, or polymethacrylate film is preferred. Commercially available cellulose acylate films (e.g., "TD80U" and "Z-TAC" manufactured by Fujifilm Corporation) can also be used. Furthermore, the support preferably has a small retardation from the viewpoint of suppressing adverse effects on the polarization degree of transmitted light and reflected light and from the viewpoint of facilitating optical inspection of the optical laminate. Specifically, the Re value is preferably 10 nm or less, and the absolute value of the Rth value is preferably 50 nm or less.

[0060] When the method for producing the optical laminate of the present invention includes a step of stretching or molding, the glass transition temperature (peak temperature of tan δ) of the support is preferably 120° C. or lower, from the viewpoint of enabling molding at low temperatures.

[0061] As the support having a glass transition temperature of 120° C. or less, various resin substrates can be used without any particular limitation. As the resin substrate, a substrate made of a cyclic olefin resin or a substrate made of a polymethacrylic acid ester is preferred because they are easily available on the market and have excellent transparency.

[0062] Examples of commercially available resin substrates include Technoloy (registered trademark) S001G, Technoloy S014G, Technoloy S000, Technoloy C001, and Technoloy C000 (Sumika Acrylic Sales Co., Ltd.), Zeonor Film (Optes Co., Ltd.), and Arton Film (JSR Corporation).

[0063] 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.

[0064] [Method for manufacturing optical laminate] The adhesion or bonding 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 from the viewpoint of being suitable for small-scale production of a wide variety of products. 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.

[0065] [Application of Optical Laminate] The optical laminate of the present invention can be incorporated into image display devices such as, for example, vehicle-mounted rearview mirrors, virtual reality display devices, electronic viewfinders, and aerial image display devices. In particular, in virtual reality display devices and electronic viewfinders having reciprocating optical systems, the optical laminate of the present invention is very useful from the viewpoint of suppressing ghosting and improving the sharpness of displayed images.

[0066] The optical laminate of the present invention is preferably used by being stuck to an optical lens, and more preferably used by being stuck to an optical lens having a curved surface portion. The optical laminate of the present invention can be used by being stuck to either the curved surface portion or the flat surface portion of an optical lens, but in terms of more excellent image sharpness, it is preferable that the optical laminate of the present invention is stuck to the curved surface portion of an optical lens having a curved surface portion.

[0067] The virtual reality display device preferably includes an image display device, a half mirror, and an optical lens formed by bonding the optical laminate of the present invention to the image display device. The optical lens is preferably an optical lens having a curved surface, and more preferably an optical lens formed by bonding the optical laminate of the present invention to the curved surface. The image display device is preferably an image display device that emits polarized light. The half mirror is preferably a half mirror having a curved surface.

[0068] 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.

[0069] [Preparation of Absorptive Polarizer 1] [Preparation of Transparent Support] <Preparation of Core Layer Cellulose Acylate Dope> The following components were placed in 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------------------------------------------------ - 100 parts by mass of cellulose acetate having an acetyl substitution degree of 2.88 - 12 parts by mass of polyester compound B described in the examples of JP 2015-227955 A - 2 parts by mass of compound F below - 430 parts by mass of methylene chloride (first solvent) - 64 parts by mass of methanol (second solvent)------------------------------------------------

[0070] Compound F

[0071]

[0072] <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.

[0073] ------------------------------------------------------------------ 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 ------------------------------------------------------------------

[0074] <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. Then, using a band casting machine, the core layer cellulose acylate dope and the outer layer cellulose acylate dopes on both sides of it were simultaneously cast onto a drum at 20°C from the casting nozzle. The film was then peeled off while the solvent content was 20% by mass, and both ends of the film in the width direction were fixed with tenter clips. The film was then stretched in the transverse direction 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 prepare an optical film (transparent support) with a thickness of 40 μm. This optical film is designated as Cellulose Acylate Film 1.

[0075] [Formation of Photo-Alignment Film PA1] The coating liquid PA1 for forming a photo-alignment film, which will be described later, was continuously applied onto the cellulose acylate film 1 (support) using a wire bar. The support on which the coating film was formed was dried with hot air at 140°C for 120 seconds. Subsequently, the coating film was irradiated with polarized ultraviolet light (10 mJ / cm ２A photo-alignment film PA1 was formed by irradiating the substrate with a TAC (triacetyl cellulose) film having a photo-alignment film. The photo-alignment film PA1 had a thickness of 1.5 μm. -------------------------------------------------- Coating liquid PA1 for forming photoalignment film -------------------------------------------------- - Polymer PA-1 (listed below) 100.00 parts by mass - EPICLON N-695 (manufactured by DIC Corporation) 55.74 parts by mass - jER YX7400 (manufactured by Mitsubishi Chemical Corporation) 18.75 parts by mass - Polymerizable polymer PA-2 (listed below) 8.01 parts by mass - Thermal cationic polymerization initiator PAG-1 (listed below) 16.75 parts by mass - Stabilizer DIPEA (listed below) 1.06 parts by mass - Butyl acetate 1230.49 parts by mass --------------------------------------------------

[0076] Polymer PA-1

[0077]

[0078] Polymerizable polymer PA-2 (wherein the numerical values ​​a, b, and c represent the content (mass%) of each repeating unit relative to the total repeating units; weight average molecular weight: 18,000)

[0079]

[0080] Thermal cationic polymerization initiator PAG-1

[0081]

[0082] Stabilizer DIPEA

[0083]

[0084] [Preparation of Optically Absorbent Anisotropic Film P1] On the obtained photo-alignment film PA1, a composition for forming an optically absorbent anisotropic film P1 having the following composition was continuously applied using a #20 wire bar to form a coating layer P1. Next, the coating layer P1 was heated at 140°C for 15 seconds and cooled to room temperature (23°C). Next, it was heated at 75°C for 15 seconds and cooled to room temperature again. Thereafter, an LED lamp (center wavelength 365 nm) was used to illuminate the coating layer P1 at an illuminance of 200 mW / cm. ２ The coating layer P1 was irradiated with ultraviolet light for 2 seconds under the irradiation conditions of 100°C for 2 seconds to form a light-absorbing anisotropic film P1 (corresponding to an anisotropic absorption layer) on the photo-alignment film PA1. The transmittance of the light-absorbing anisotropic film was measured using a spectrophotometer in the wavelength range of 280 to 780 nm, and the average visible light transmittance was 43%.

[0085] 0.04 parts by mass of the following adhesion improver A-1; 0.07 parts by mass of polymerization initiator IRGACUREOXE-02 (manufactured by BASF); 0.006 parts by mass of the following surfactant F-2; 94.96 parts by mass of cyclopentanone; Benzyl alcohol 2.43 parts by mass ――――――――――――――――――――――――――――――

[0086] Dichroic dye Dye-Y1

[0087]

[0088] Dichroic dye Dye-M1

[0089]

[0090] Dichroic dye Dye-C1

[0091]

[0092] Dichroic dye Dye-C2

[0093]

[0094] Liquid crystal compound L-1 (In the formula below, the numerical values ​​("59", "15", "26") shown for each repeating unit represent the content (% by mass) of each repeating unit relative to all repeating units. Weight average molecular weight: 18,000)

[0095]

[0096] Liquid crystal compound L-3

[0097]

[0098] Surfactant F-2 (wherein the numerical value for each repeating unit represents the content (mass%) of each repeating unit relative to the total repeating units. Ac represents —C(O)CH ３ Weight average molecular weight: 15,000

[0099]

[0100] Adhesion improver A-1

[0101]

[0102] [Formation of Barrier Layer B1] Coating liquid B1 having the following composition was continuously applied onto the optically absorptive anisotropic film P1 using a wire bar. This was then dried with hot air at 80°C for 5 minutes to obtain a laminate X1 having a barrier layer B1 made of polyvinyl alcohol (PVA) with a thickness of 1.0 μm. This resulted in an absorptive polarizer 1 having a cellulose acylate film 1 (transparent support), a photoalignment film PA1, an optically absorptive anisotropic film P1, and a barrier layer B1 adjacent to each other in this order. ----------------------------------- Composition of coating liquid B1 for forming barrier layer ----------------------------------- 3.80 parts by mass of modified polyvinyl alcohol described below 0.20 parts by mass of initiator Irg2959 70 parts by mass of water 30 parts by mass of methanol

[0103] Modified Polyvinyl Alcohol

[0104]

[0105] [Preparation of λ / 4 Retardation Plate 1] A λ / 4 retardation plate 1 having a reverse wavelength dispersion property and including a cellulose acylate film as a temporary support and a fixed liquid crystal phase was prepared with reference to the method described in paragraphs 0151 to 0163 of JP 2020-084070 A. The retardation values ​​of the obtained λ / 4 retardation plate 1 were Re = 142 nm and Rth = 71 nm.

[0106] [Preparation of Reflective Circular Polarizer 1] [Preparation of Reflective Layer Coating Solutions R-1 and R-4]

[0107] The compositions shown below were stirred and dissolved in a container kept at 70°C to prepare coating solutions R-1 and R-4 for reflective layers, respectively. Here, R represents a coating solution using rod-like liquid crystals.

[0108] -------------------------------------------------- Coating liquids R-1 and R-4 for reflective layer -------------------------------------------------- Methyl ethyl ketone 120.9 parts by mass Cyclohexanone 21.3 parts by mass Mixture of the following rod-shaped liquid crystal compounds 100.0 parts by mass Photopolymerization initiator C 1.00 parts by mass Chiral agent A listed in Table 1 below Surfactant F-3 0.027 parts by mass Surfactant F-4 listed below --------------------------------

[0109] Table 1. Amount of chiral agent in coating solution containing rod-shaped liquid crystal compound

[0110]

[0111] A mixture of rod-shaped liquid crystal compounds

[0112] In the above mixture, 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.

[0113] Chiral agent A

[0114]

[0115] Surfactant F-3

[0116]

[0117] Surfactant F-4

[0118]

[0119] Photopolymerization initiator C

[0120]

[0121] The chiral agent A is a chiral agent whose helical twisting power (HTP) is reduced by light.

[0122] (Reflective layer coating solutions D-2, D-3, and D-5) The compositions shown below were stirred and dissolved in a container kept at 50° C. to prepare reflective layer coating solutions D-2, D-3, and D-5, respectively. Here, D represents a coating solution using a discotic liquid crystal compound.

[0123] ------------------------------------------------ Coating solutions D-2, D-3, D-5 for reflective layer ------------------------------------------------ ・Discotic liquid crystal compound (A) below: 80 parts by mass ・Discotic liquid crystal compound (B) below: 20 parts by mass ・Polymerizable monomer E1 10 parts by mass ・Surfactant F-5 0.3 parts by mass ・Photopolymerization initiator (Irgacure 907, manufactured by BASF) 3 parts by mass ・Chiral agent A See Table 2 ・Methyl ethyl ketone 290 parts by mass ・Cyclohexanone 50 parts by mass ------------------------------------------------

[0124] Table 2. Amount of chiral agent in coating solution containing discotic liquid crystal compound

[0125]

[0126] Discotic Liquid Crystal Compound (A)

[0127]

[0128] Discotic Liquid Crystal Compound (B)

[0129]

[0130] Polymerizable Monomer E1

[0131]

[0132] Surfactant F-5

[0133]

[0134] <Coating Solution PC-1 for Optical Interference Layer> The composition shown below was stirred and dissolved in a container kept at 60° C. to prepare Coating Solution PC-1 for Optical Interference Layer.

[0135] -------------------------------- Coating liquid PC-1 for optical interference layer ---------------------------------- 3011.0 parts by mass of methyl isobutyl ketone 100.0 parts by mass of the mixture of rod-shaped liquid crystal compounds described above 5.1 parts by mass of photopolymerization initiator G described below 3.0 parts by mass of photoacid generator PAG-2 described below 2.0 parts by mass of hydrophilic polymer described below 1.9 parts by mass of vertical alignment agent described below 4.2 parts by mass of viscosity reducer described below 8.0 parts by mass of material for interlayer photoalignment film described below 0.2 parts by mass of the stabilizer DIPEA described above ----------------------------------

[0136] Photopolymerization initiator G

[0137]

[0138] Photoacid generator PAG-2

[0139]

[0140] hydrophilic polymer

[0141]

[0142] Vertical alignment agent

[0143]

[0144] Viscosity reducer

[0145]

[0146] Materials for interlayer photo-alignment films

[0147]

[0148] [Preparation of Reflective Circular Polarizer 1] A 60 μm thick TAC (triacetyl cellulose) film (TG60, manufactured by Fujifilm Corporation) was prepared as a temporary support.

[0149] The above-prepared coating solution for optical interference layer PC-1 was applied to the TAC film using a wire bar coater, and then dried at 80°C for 60 seconds. Thereafter, the film was exposed to light at 78°C in a low-oxygen atmosphere (100 ppm) at an irradiation dose of 300 mJ / cm. ２ The 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 having cinnamoyl groups on the outermost surface and a film thickness of 80 nm. The refractive index nI measured using an OPTM interference film thickness meter (manufactured by Otsuka Electronics Co., Ltd., analyzed using the least squares method) was 1.57. The Rth measured at a wavelength of 550 nm using an Axoscan (manufactured by Axometrics) was -8 nm.

[0150] Next, the illuminance is 7 mW / cm ２ , irradiation amount 7.9mJ / cm ２ The positive C-plate side was irradiated 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 a wavelength of 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 reflective layer was irradiated with polarized UV 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 rpm). The light was irradiated from the cholesteric liquid crystal layer side. The coating thickness was adjusted so that the cured first green light reflective layer had a thickness of 2.4 μm.

[0151] Next, the first green light reflecting layer surface was subjected to a discharge of 150 W·min / m ２ After corona treatment, the reflective layer coating solution D-2 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-reflecting layer (second light-reflecting layer) on the first green 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 second blue light-reflecting layer after curing was 1.7 μm.

[0152] Next, the reflective layer coating solution D-3 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 blue 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 blue light reflective layer after curing was 3.8 μm.

[0153] Next, the reflective layer coating solution R-4 was applied onto the blue 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 / m², thereby forming a red light reflective layer (fourth light reflective layer) on the blue 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 4.8 μm.

[0154] Next, the red light reflecting layer surface was subjected to a discharge of 150 W·min / m ２After corona treatment at 400°C, the reflective layer coating solution D-5 was applied to the corona-treated surface using a wire bar coater. The coating film was then 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, the 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 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 3.3 μm. In this way, a reflective circular polarizer 1 having a reflective layer in which a cholesteric liquid crystal phase was fixed on a temporary support was produced.

[0155] Table 3 shows the central reflection wavelength and film thickness of each reflective layer of the reflective circular polarizer 1 produced. 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 short-wavelength and long-wavelength wavelengths that show half-values ​​of the peak reflectance. The central reflection wavelength (the central wavelength of reflected light) was confirmed by creating a film coated with only a single layer. The film thickness was confirmed using a scanning electron microscope (SEM).

[0156] Table 3. Characteristics of the light-reflecting layer of reflective circular polarizer 1

[0157]

[0158] The temporary support was peeled off from the produced reflective circular polarizer 1, and measurement was performed using a dynamic viscoelasticity measuring device (DVA-200 manufactured by IT Measurement Control Co., Ltd.), which revealed that the glass transition temperature of reflective circular polarizer 1 was 98° C. Furthermore, the dimensional change when reflective circular polarizer 1 was heated for 1 minute at a temperature 20° C. higher than the glass transition temperature, i.e., 118° C., was 0.6% shrinkage in all directions.

[0159] [Preparation of Reflective Linear Polarizer 1] An Apple iPad (registered trademark) tablet computer was disassembled, and the liquid crystal panel was removed. A polarizing plate including a reflective linear polarizer was attached to the back surface of the liquid crystal panel. The polarizing plate was peeled off from the liquid crystal panel, and the peeled polarizing plate was immersed in 80°C hot water for 1 minute to peel off only the reflective linear polarizer. The obtained reflective linear polarizer was used as reflective linear polarizer 1. A part of reflective linear polarizer 1 was cut out, and the cross section in the thickness direction was observed with an SEM. It was found that reflective linear polarizer 1 was a reflective linear polarizer formed by alternately laminating multiple layers of two different types of birefringent layers. The thickness of reflective linear polarizer 1 was 17 μm. The reflective linear polarizer 1 was measured using a dynamic viscoelasticity measuring device ("DVA-200" manufactured by IT Measurement Control Co., Ltd.), and the glass transition temperature of reflective linear polarizer 1 was found to be 98°C. The dimensional change of the reflective linear polarizer 1 when heated for 1 minute at a temperature 20° C. higher than the glass transition temperature, i.e., 118° C., was 1.1% in the direction of the reflection axis, and the dimensional change of the reflective linear polarizer 1 when heated for 1 minute at 118° C. was 1.0% in the direction of the transmission axis.

[0160] [Preparation of Reflective Linear Polarizer 2] Because the dimensional change of reflective linear polarizer 1 was greater than 0.8%, reflective linear polarizer 1 was heated at 140°C for 5 minutes to cause it to shrink in all directions, including the direction of the reflection axis. The reflective linear polarizer thus obtained was used as reflective linear polarizer 2. When reflective linear polarizer 2 was heated at 118°C for 1 minute, the dimensional change was 0.1% shrinkage in the direction of the reflection axis. Furthermore, when reflective linear polarizer 2 was heated at 118°C for 1 minute, the dimensional change was greater than 0% and less than 0.1% shrinkage in all directions.

[0161] Reference Example 1 Preparation of Optical Laminate 1 An ultraviolet-curable adhesive, Aronix (registered trademark) UVX-6282, manufactured by Toagosei Co., Ltd., was applied to a PMMA film, Technoloy S001G, manufactured by Sumika Acrylic Sales Co., Ltd. Next, the absorptive polarizer 1 described above was attached to the coating of the ultraviolet-curable adhesive, and then irradiated with ultraviolet light (300 mJ / cm ２) to cure the adhesive, thereby bonding the PMMA film and the absorptive polarizer 1. The cellulose acylate film 1 used as a temporary support (transparent support) for the absorptive polarizer 1 was peeled off and removed after bonding. In the bonded absorptive polarizer 1, a barrier layer B1, a light absorption anisotropic film P1, and a photo-alignment film PA1 were disposed from the coating film side of the ultraviolet-curable adhesive. Using the same procedure as above, a λ / 4 retardation plate 1 and a reflective circular polarizer 1 were further bonded in this order on the absorptive polarizer 1. The temporary supports of the λ / 4 retardation plate 1 and the reflective circular polarizer 1 were both peeled off and removed from the laminate after bonding. Next, a pressure-sensitive adhesive sheet "NCF-D692(5)" manufactured by Lintec Corporation was bonded to the reflective circular polarizer 1, and then an antireflection film "AR200-T0810-JD" manufactured by Dexerials Corporation was bonded thereto. Furthermore, a pressure-sensitive adhesive sheet "NCF-D692(15)" manufactured by Lintec Corporation was laminated onto the above-mentioned PMMA film "Technoloy S001G." In this way, an optical laminate 1 of Reference Example 1 was obtained. The storage modulus G' of the pressure-sensitive adhesive sheet measured by the torsional shear method using the above-mentioned method was 3.2 MPa.

[0162] In the optical laminate 1 of Reference Example 1, a pressure-sensitive adhesive sheet, a PMMA film, an adhesive layer, an absorptive polarizer 1, an adhesive layer, a λ / 4 retardation plate 1, an adhesive layer, a reflective circular polarizer 1, a pressure-sensitive adhesive sheet, and an antireflection film were arranged in this order. Furthermore, the λ / 4 retardation plate 1 and the absorptive polarizer 1 were arranged so that the orientation of the slow axis of the λ / 4 retardation plate 1 and the orientation of the absorption axis of the absorptive polarizer 1 formed an angle of 45°.

[0163] [Fabrication of Virtual Reality Display Device 1] A virtual reality display device "VIVE FLOW (registered trademark)" manufactured by HTC was disassembled, and optical lenses were removed from the lens barrel. The "VIVE FLOW" is a virtual reality display device that employs a pancake lens, and its image display device uses a liquid crystal display device that emits circularly polarized light using a polarizing plate attached to its surface. The optical lenses removed were a biconvex lens with a half-mirror coating on one side, and a plano-convex lens with an optical laminate attached to its flat surface. Next, the optical laminate 1 was attached to the flat surface of a plano-convex lens "#45-151" manufactured by Edmund, with the adhesive sheet on the surface of the optical laminate 1 in contact with the flat surface. The resulting plano-convex lens with the optical laminate 1 attached was heated at 115°C for 5 minutes to strengthen the adhesion between the optical laminate 1 and the plano-convex lens. The obtained plano-convex lens with optical laminate 1 was assembled into the lens barrel of "VIVE FLOW" in place of the plano-convex lens of "VIVE FLOW", and the biconvex lens with half mirror coating that had been removed was assembled into the lens barrel, thereby producing the virtual reality display device 1 of Reference Example 1.

[0164] Example 1 Preparation of Optical Laminate 2 An ultraviolet-curable adhesive, Aronix UVX-6282, manufactured by Toagosei Co., Ltd., was applied to a PMMA film, Technoloy S001G, manufactured by Sumika Acrylic Sales Co., Ltd., and then the absorptive polarizer 1 described above was attached to the coating of the ultraviolet-curable adhesive. The laminate was then irradiated with ultraviolet light (300 mJ / cm ２) to cure the adhesive, thereby bonding the PMMA film and the absorptive polarizer 1. The cellulose acylate film used as a temporary support (transparent support) for the absorptive polarizer 1 was peeled off and removed after bonding. In the bonded absorptive polarizer 1, a barrier layer B1, a light-absorbing anisotropic film P1, and a photo-alignment film PA1 were disposed from the coating film side of the ultraviolet-curable adhesive. Using the same procedure as above, a reflective linear polarizer 2 and a λ / 4 retardation plate 1 were further bonded in this order on the absorptive polarizer 1. The temporary support of the λ / 4 retardation plate 1 was peeled off and removed from the laminate after bonding. Next, a pressure-sensitive adhesive sheet "NCF-D692(5)" manufactured by Lintec Corporation was bonded to the λ / 4 retardation plate 1, and then an antireflection film "AR200-T0810-JD" manufactured by Dexerials Corporation was bonded thereto. Furthermore, an adhesive sheet "NCF-D692(15)" manufactured by Lintec Corporation was attached onto the above-mentioned PMMA film "Technoloy S001G." In this way, an optical laminate 2 of Example 1 was obtained.

[0165] In the optical laminate 2 of Example 1, the pressure-sensitive adhesive sheet, PMMA film, adhesive layer, absorptive polarizer 1, adhesive layer, reflective linear polarizer 2, adhesive layer, λ / 4 retardation plate 1, pressure-sensitive adhesive sheet, and antireflection film were arranged in this order. The absorptive polarizer 1 and the reflective linear polarizer 2 were arranged so that the orientation of the absorption axis of the absorptive polarizer 1 and the orientation of the reflection axis of the reflective linear polarizer 2 were parallel to each other, and the reflective linear polarizer 2 and the λ / 4 retardation plate 1 were arranged so that the orientation of the reflection axis of the reflective linear polarizer 2 and the orientation of the slow axis of the λ / 4 retardation plate 1 formed an angle of 45°.

[0166] [Fabrication of virtual reality display device 2] Virtual reality display device 2 of Example 1 was fabricated in the same manner as Reference Example 1, except that optical laminate 2 was bonded to the flat surface of a plano-convex lens "#45-151" manufactured by Edmund, instead of optical laminate 1.

[0167] [Comparative Example 1] [Preparation of Optical Laminate 3] Optical laminate 3 of Comparative Example 1 was prepared in the same manner as optical laminate 2, except that reflective linear polarizer 2 was used instead of reflective linear polarizer 1.

[0168] [Fabrication of virtual reality display device 3] Virtual reality display device 3 of Comparative Example 1 was fabricated in the same manner as Reference Example 1, except that optical laminate 3 was bonded to the flat surface of a plano-convex lens "#45-151" manufactured by Edmund, instead of optical laminate 1.

[0169] Example 2 Fabrication of Virtual Reality Display Device 4 The optical laminate 2 was attached to the concave side of 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, such that the adhesive sheet on the surface of the optical laminate 2 was in contact with the concave surface of the convex meniscus lens. The obtained lens with the optical laminate 2 attached was heated at 115°C for 5 minutes to strengthen the adhesion between the optical laminate 2 and the lens. Note that the attachment of the optical laminate 2 to the concave surface of the convex meniscus lens was performed using a known vacuum molding method. Specifically, the optical laminate 2 was attached to the concave surface of the convex meniscus lens with reference to Japanese Patent No. 3733564. The obtained lens with the optical laminate 2 attached was assembled into the lens barrel of the "VIVE FLOW" in place of the plano-convex lens of the "VIVE FLOW". The concave side of the lens was set to be the viewing side. The half-mirror-coated biconvex lens was then attached to the lens barrel, thereby producing the virtual reality display device 4 of Example 2.

[0170] [Evaluation of Image Sharpness] In the virtual reality display devices produced in Reference Example 1, Example 1, Example 2, and Comparative Example 1, a black and white checkered pattern was displayed on the image display device, and the degree of image sharpness was visually evaluated using the following three-level scale. When image sharpness is poor, part or all of the checkered pattern appears distorted. A: Distortion of the checkered pattern is barely noticeable. B: Distortion of the checkered pattern is slightly noticeable, but not noticeable when viewing the displayed image. C: Distortion of the checkered pattern is clearly noticeable. The evaluation results of image sharpness are shown in Table 4.

[0171] Table 4: Evaluation results of the virtual reality display devices of the reference example, working example, and comparative example

[0172]

[0173] As can be seen from Table 1, the virtual reality display devices of Examples 1 and 2 had higher image sharpness than Comparative Example 1. This is presumably because, in the virtual reality display devices of Examples 1 and 2, the dimensional change due to heating of the reflective polarizer in the optical laminate was kept sufficiently small, resulting in improved smoothness of the optical laminate.

[0174] The above describes in detail the virtual reality display device of the present invention, but the present invention is not limited to the above examples, and various improvements and modifications may of course be made within the scope that does not deviate from the gist of the present invention.

[0175] 100 Optical laminate 300 Half mirror 400 Circular polarizer 500 Image display panel 1000 Light rays forming a virtual image

Claims

1. An optical laminate including a reflective polarizer, an absorptive polarizer, and an adhesive layer, the reflective polarizer exhibits a dimensional change of 0% or more and less than 0.8% shrinkage when heated for 1 minute at a temperature 20°C higher than the glass transition temperature of the reflective polarizer in at least one in-plane direction; The optical laminate, wherein the reflective polarizer is a reflective linear polarizer formed by alternately laminating two or more different types of birefringent layers.

2. The optical laminate according to claim 1 , wherein the absorptive polarizer has an anisotropic absorbing layer containing at least a liquid crystalline compound and a dichroic dye.

3. At least one of the adhesive layers is a layer made of a pressure-sensitive adhesive sheet, 2. The optical laminate according to claim 1, wherein the pressure-sensitive adhesive sheet has a storage modulus G' of 0.8 MPa or more at 20°C as measured by a torsional shear method.

4. 2. The optical laminate according to claim 1, wherein at least one of the adhesive layers is a layer formed by curing an adhesive layer-forming composition containing an ultraviolet-curable adhesive.

5. The optical laminate according to claim 1 , further comprising at least one λ / 4 retardation plate.

6. The optical laminate according to claim 5 , wherein the λ / 4 retardation plate has a fixed liquid crystal phase.

7. An optical laminate as described in claim 1, wherein the reflective polarizer exhibits a dimensional change of 0% or more but less than 0.1% shrinkage in all directions in the plane when heated for 1 minute at a temperature 20°C higher than the glass transition temperature of the reflective polarizer.

8. An optical laminate as described in claim 1, wherein the glass transition temperature of the reflective polarizer is 95°C or higher.

9. The reflective polarizer exhibits a dimensional change of 0% or more and less than 0.1% shrinkage in all in-plane directions when heated for 1 minute at a temperature 20°C higher than the glass transition temperature of the reflective polarizer, The optical laminate according to claim 1 , wherein the reflective polarizer has a glass transition temperature of 95° C. or higher.

10. An optical lens having a curved surface, An optical lens having the optical laminate according to any one of claims 1 to 9 bonded to the curved surface portion.

11. A virtual reality display device comprising: an image display device that emits polarized light; a half mirror having a curved surface; and the optical lens according to claim 10.