Method for manufacturing optical laminate

Abstract

Provided is a method for manufacturing an optical laminate including: a phase difference member that has a first main surface and a second main surface that face each other, converts linearly polarized light incident from the first main surface side into circularly polarized light, and emits the circularly polarized light from the second main surface side; and a protective member that has a slow axis and is disposed on the second main surface side of the phase difference member. The method includes laminating the phase difference member and the protective member such that an angle formed by a polarization direction of the linearly polarized light and the slow axis of the protective member is 15° or less or 75°-105°.

Description

Method for manufacturing optical laminate

[0001] The present invention relates to a method for producing an optical laminate.

[0002] Image display devices, such as liquid crystal display devices and electroluminescence (EL) display devices (e.g., organic EL display devices), are rapidly becoming popular. Optical components such as retardation components and polarizing components are generally used in image display devices to realize image display and improve image display performance (see, for example, Patent Document 1). These optical components can be integrated in advance and mounted on the image display device as an optical laminate.

[0003] In recent years, new applications of image display devices have been developed. For example, goggles with displays (VR goggles) for realizing virtual reality (VR) have begun to be commercialized. Since the use of VR goggles in various situations is being considered, there is a demand for lighter weight, improved visibility, and the like.

[0004] Japanese Patent Application Laid-Open No. 2021-103286

[0005] The weight reduction of the VR goggles can be achieved, for example, by thinning the lenses used in the VR goggles. On the other hand, there is also a need for the development of an optical laminate including the optical member suitable for a display system using lenses.

[0006] In view of the above, a main object of the present invention is to provide a method for manufacturing an optical laminate that can effectively achieve weight reduction of VR goggles while improving visibility.

[0007] [1] According to one aspect of the present invention, there is provided a method for producing an optical laminate including a retardation member having a first principal surface and a second principal surface opposed to each other, the retardation member converting linearly polarized light incident on the first principal surface side into circularly polarized light and emitting the circularly polarized light from the second principal surface side, and a protective member having a slow axis and arranged on the second principal surface side of the retardation member, the method comprising laminating the retardation member and the protective member so that the angle between the polarization direction of the linearly polarized light and the slow axis of the protective member is 15° or less or 75° to 105°. [2] In the method according to the above [1], the retardation member may include a λ / 4 layer having an Re(550) of 100 nm to 190 nm, and laminating the retardation member and the protective member may comprise laminating the λ / 4 layer and the protective member so that the angle between the slow axis of the λ / 4 layer and the slow axis of the protective member is 30° to 60°. [3] In the manufacturing method described in [2] above, laminating the retardation member and the protective member may include laminating the λ / 4 layer and the protective member, both of which are in the form of sheets. [4] The manufacturing method described in [3] above may further include punching the long λ / 4 layer so that its slow axis is approximately perpendicular or parallel to the side direction to obtain the rectangular λ / 4 layer, and punching the long protective member so that its slow axis forms an angle of 30° to 60° with the side direction to obtain the rectangular protective member. [5] The manufacturing method described in [3] above may further include punching the long λ / 4 layer so that its slow axis forms an angle of 30° to 60° with the side direction to obtain the rectangular λ / 4 layer, and punching the long protective member so that its slow axis is approximately perpendicular or parallel to the side direction to obtain the rectangular protective member. [6] In the manufacturing method according to the above [4] or [5], the long λ / 4 layer may have a slow axis in a direction substantially parallel to the longitudinal direction or the width direction. [7] In the manufacturing method according to the above [2], laminating the retardation member and the protective member may include continuously laminating the long λ / 4 layer and the protective member with their longitudinal directions aligned.[8] In the manufacturing method according to [7] above, the elongated λ / 4 layer may have a slow axis in a direction of 30° to 60° relative to the longitudinal direction. [9] In the manufacturing method according to any one of [1] to [8] above, the retardation member and the protective member may be laminated via a pressure-sensitive adhesive layer.

[10] In the manufacturing method according to [9] above, the protective member having the pressure-sensitive adhesive layer provided on one surface thereof may be laminated with the retardation member.

[11] In the manufacturing method according to any one of [1] to

[10] above, the protective member may include a substrate, and the substrate may include at least one resin selected from an acrylic resin and a triacetyl cellulose resin.

[0008] According to the method for producing an optical laminate according to an embodiment of the present invention, the axial angle between the slow axis of a retardation member that converts linearly polarized light into circularly polarized light and the slow axis of a protective member used together with the retardation member is adjusted, thereby making it possible to obtain an optical laminate that can effectively achieve weight reduction of VR goggles while improving visibility.

[0009] 1 is a schematic cross-sectional view showing a schematic configuration of an optical laminate that can be manufactured by a manufacturing method according to an embodiment of the present invention. FIG. 2 is a schematic cross-sectional view showing a schematic configuration of an optical laminate that can be manufactured by a manufacturing method according to an embodiment of the present invention. FIG. 3 is a schematic cross-sectional view showing a schematic configuration of an example of a retardation member used in a manufacturing method according to an embodiment of the present invention. FIG. 4 is a schematic cross-sectional view showing a schematic configuration of an example of a retardation member used in a manufacturing method according to an embodiment of the present invention. FIG. 5 is a schematic view illustrating a polarization state of light passing through the optical laminate shown in FIG. 1. FIG. 6 is a schematic view illustrating an example of a method for manufacturing a rectangular λ / 4 layer and a protective member. FIG. 7 is a schematic view illustrating an example of a method for manufacturing a rectangular λ / 4 layer and a protective member. FIG. 8 is a schematic view illustrating a polarization state of light passing through the optical laminate shown in FIG. 2. FIG. 9 is a schematic side view showing an example of a specific configuration of a part of the display system shown in FIG. 9. FIG. 10 is a schematic side view showing an example of a specific configuration of a part of the display system shown in FIG. 1 is a graph showing the difference between the ellipticity of transmitted light measured for the optical laminates produced in the Examples and Comparative Examples and the ellipticity of transmitted light measured for the optical laminate of Reference Example 1. 2 is a graph showing the difference between the ellipticity of transmitted light measured for the optical laminates produced in the Examples and Comparative Examples and the ellipticity of transmitted light measured for the optical laminate of Reference Example 1. 3 is a graph showing the difference between the ellipticity of transmitted light measured for the optical laminates produced in the Examples and Comparative Examples and the ellipticity of transmitted light measured for the optical laminate of Reference Example 2. 4 is a graph showing the difference between the ellipticity of transmitted light measured for the optical laminates produced in the Examples and Comparative Examples and the ellipticity of transmitted light measured for the optical laminate of Reference Example 2.

[0010] Hereinafter, embodiments of the present invention will be described with reference to the drawings, but the present invention is not limited to these embodiments. In order to clarify the description, the drawings may schematically show the width, thickness, shape, etc. of each part compared to the embodiments, but these are merely examples and do not limit the interpretation of the present invention. Furthermore, in the drawings, the same or equivalent elements are given the same reference numerals, and duplicate explanations may be omitted.

[0011] (Definition of Terms and Symbols) The definitions of terms and symbols used in this specification are as follows. (1) Refractive Index (nx, ny, nz) "nx" is the refractive index in the direction in which the in-plane refractive index is maximum (i.e., the slow axis direction), "ny" is the refractive index in the in-plane direction perpendicular to the slow axis (i.e., the fast axis direction), and "nz" is the refractive index in the thickness direction. (2) In-Plane Retardation (Re) "Re(λ)" is the in-plane retardation measured with light having a wavelength of λ nm at 23°C. For example, "Re(550)" is the in-plane retardation measured with light having a wavelength of 550 nm at 23°C. Re(λ) is calculated by the formula: Re(λ) = (nx - ny) × d, where d (nm) is the thickness of the layer (film). (3) Thickness Direction Retardation (Rth) "Rth(λ)" is the retardation in the thickness direction measured with light having a wavelength of λ nm at 23°C. For example, "Rth(550)" is the retardation in the thickness direction measured with light having a wavelength of 550 nm at 23°C. Rth(λ) is calculated by the formula: Rth(λ) = (nx - nz) × d, where d (nm) is the thickness of the layer (film). (4) Nz Coefficient The Nz coefficient is calculated by Nz = Rth / Re. (5) Angle When an angle is referred to in this specification, unless otherwise specified, the angle includes both clockwise (+) and counterclockwise (-) angles relative to a reference direction. Therefore, for example, "45°" means ±45°. Furthermore, in this specification, "substantially parallel" includes a range of 0° ±10°, preferably within a range of 0° ±5°, more preferably within a range of 0° ±3°, and even more preferably within a range of 0° ±1°. "Approximately perpendicular" encompasses the range of 90°±10°, preferably within the range of 90°±5°, more preferably within the range of 90°±3°, and even more preferably within the range of 90°±1°.

[0012] A. Method for Producing Optical Laminate A method for producing an optical laminate according to an embodiment of the present invention is a method for producing an optical laminate including: a phase difference member having a first main surface and a second main surface opposing each other, converting linearly polarized light incident from the first main surface side into circularly polarized light and outputting the circularly polarized light from the second main surface side; and a protective member having a slow axis and arranged on the second main surface side of the phase difference member, the method including laminating the phase difference member and the protective member so that the angle between the polarization direction of the linearly polarized light and the slow axis of the protective member is, for example, 15° or less or 75° to 105°. Specifically, in the optical laminate, the retardation member is arranged so that its slow axis forms a predetermined angle with the polarization direction of linearly polarized light incident from the first main surface side, thereby being capable of converting the linearly polarized light into circularly polarized light. In the method for manufacturing the optical laminate, the retardation member and the protective member are laminated so that the angle between the polarization direction of the linearly polarized light and the slow axis of the protective member (in other words, the angle between the slow axis of the retardation member and the slow axis of the protective member) is within a predetermined range. The method for manufacturing an optical laminate according to an embodiment of the present invention may further include laminating a polarizing member on the side of the retardation member opposite to the side on which the protective member is arranged (in other words, the first main surface side). The lamination of the retardation member and the polarizing member may be performed before or after the lamination of the retardation member and the protective member.

[0013] A-1. Overall Configuration of Optical Laminate Fig. 1 is a schematic cross-sectional view showing the outline of an example of an optical laminate obtained by a manufacturing method of an optical laminate according to an embodiment of the present invention. The optical laminate 100A includes a phase difference member 20 having a first main surface 20a and a second main surface 20b facing each other, which converts linearly polarized light incident from the first main surface 20a side into circularly polarized light and emits it from the second main surface 20b side, and a protective member 30 having a slow axis and arranged on the second main surface 20b side of the phase difference member 20.

[0014] 2 is a schematic cross-sectional view showing the general configuration of another example of an optical laminate obtained by the method for producing an optical laminate according to an embodiment of the present invention. The optical laminate 100B includes a phase difference member 20 having a first main surface 20a and a second main surface 20b facing each other, which converts linearly polarized light incident on the first main surface 20a into circularly polarized light and emits it from the second main surface 20b, a protective member 30 having a slow axis and arranged on the second main surface 20b side of the phase difference member 20, and a polarizing member 10 arranged on the first main surface 20a side of the phase difference member 20. The polarizing member 10 may be an absorptive polarizing member and / or a reflective polarizing member. The polarizing member 10 can emit the linearly polarized light as transmitted light or reflected light to the first main surface 20a of the phase difference member 20.

[0015] In the optical laminate, the ellipticity of the circularly polarized light CP1 emitted from the second main surface side when linearly polarized light is incident on the first main surface side of the retardation member (wavelength 550 nm, polar angle 0 °) is preferably higher, for example, 0.94 or more, preferably 0.95 or more, more preferably 0.96 or more. Furthermore, the difference between the ellipticity of the circularly polarized light CP1 at a wavelength of 450 nm, 550 nm, or 650 nm (polar angle 0 °) and the ellipticity of the circularly polarized light CP2 emitted after the circularly polarized light CP1 passes through the protective member (polar angle 0 °) (| ellipticity of circularly polarized light CP1 - ellipticity of circularly polarized light CP2 |) is, for example, 0.02 or less, preferably 0 to 0.015, more preferably 0 to 0.01, and even more preferably 0 to 0.005. The ellipticity is the ratio of the minor axis / major axis of the circularly polarized light; for example, the ellipticity is 1 when the light is completely circularly polarized, and the ellipticity is 0 when the light is completely linearly polarized. In this specification, the term "circularly polarized light" may include not only perfectly circularly polarized light, whose ellipticity is 1, but also elliptically polarized light, whose ellipticity is less than 1. Furthermore, "ellipticity" refers to the absolute value of ellipticity.

[0016] The optical laminate may be in a long shape or in a sheet shape. In this specification, "long" means an elongated shape having a length that is sufficiently longer than its width, and includes, for example, an elongated shape having a length that is 10 times or more, preferably 20 times or more, the width. A long optical laminate can be wound into a roll.

[0017] [Retardation Member] The retardation member 20 has a first main surface 20 a and a second main surface 20 b facing each other, and can convert linearly polarized light incident from the first main surface 20 a side into circularly polarized light and emit it from the second main surface 20 b side. Figures 3 and 4 are schematic cross-sectional views each showing an outline of the configuration of an example of the retardation member.

[0018] The phase difference member 20 shown in Fig. 3 is configured to convert linearly polarized light into circularly polarized light using a λ / 4 layer 21 having an Re(550) of 100 nm to 190 nm (Configuration 1). Specifically, the phase difference member 20 of Configuration 1 includes a λ / 4 layer 21 having an Re(550) of 100 nm to 190 nm, and the λ / 4 layer 21 is arranged so that its slow axis direction forms an angle of, for example, 40° to 50°, 42° to 48°, or approximately 45° with the polarization direction of the linearly polarized light to be converted into circularly polarized light. The phase difference member 20 of Configuration 1 can also convert circularly polarized light incident on one main surface side into linearly polarized light and emit it from the other main surface side.

[0019] 4 is configured to convert linearly polarized light into circularly polarized light by a λ / 2 layer 22 having an Re(550) of 200 nm to 330 nm and a λ / 4 layer 21 having an Re(550) of 100 nm to 190 nm, which are arranged in this order from the first main surface 20a side (Configuration 2). Specifically, in the phase difference member 20 of Configuration 2, the λ / 2 layer 22 is arranged so that its slow axis direction forms an angle of, for example, 5° to 35°, 10° to 20°, 12° to 18°, or about 15° with the polarization direction of linearly polarized light to be converted into circularly polarized light, and the λ / 4 layer 21 is arranged so that its slow axis direction forms an angle of, for example, 55° to 85°, 70° to 80°, 72° to 78°, or about 75° with the polarization direction of the linearly polarized light. Alternatively, the λ / 2 layer 22 is arranged so that its slow axis direction forms an angle of, for example, 55° to 85°, 70° to 80°, 72° to 78°, or approximately 75° with the polarization direction of the linearly polarized light, and the λ / 4 layer 21 is arranged so that its slow axis direction forms an angle of, for example, 5° to 35°, 10° to 20°, 12° to 18°, or approximately 15° with the polarization direction of the linearly polarized light. In the retardation member 20 of configuration 2, the angle formed between the slow axis direction of the λ / 2 layer 22 and the slow axis direction of the λ / 4 layer 21 can be, for example, 50° to 70°, 55° to 65°, 57° to 63°, or approximately 60°. The retardation member 20 of configuration 2 can convert circularly polarized light incident from the second major surface 20b side into linearly polarized light and emit it from the first major surface 20a side.

[0020] The retardation members of Configuration 1 and Configuration 2 may each further include another retardation layer depending on the purpose. When the retardation member has a laminated structure, each layer is typically laminated via an adhesive layer. The adhesive layer may be formed of an adhesive or a pressure-sensitive adhesive. Specifically, the adhesive layer may be an adhesive layer or a pressure-sensitive adhesive layer. The thickness of the adhesive layer is, for example, 0.05 μm to 30 μm.

[0021] <λ / 4 Layer> The in-plane retardation Re(550) of the λ / 4 layer 21 is, for example, 100 nm to 190 nm, may be 110 nm to 180 nm, may be 130 nm to 160 nm, or may be 135 nm to 155 nm.

[0022] The λ / 4 layer preferably exhibits an inverse dispersion wavelength characteristic in which the retardation value increases with the wavelength of the measurement light. The Re(450) / Re(550) of the λ / 4 layer may be, for example, less than 1, 0.95 or less, or even less than 0.90, or even 0.85 or less. The Re(450) / Re(550) of the λ / 4 layer may be, for example, 0.75 or more. Furthermore, for example, the λ / 4 layer may exhibit a flat wavelength dispersion characteristic in which the retardation value changes little with the wavelength of the measurement light. In this case, the Re(450) / Re(550) of the λ / 4 layer may be, for example, 0.99 to 1.03, and the Re(650) / Re(550) of the λ / 4 layer may be, for example, 0.98 to 1.02.

[0023] The λ / 4 layer preferably has a refractive index characteristic that satisfies the relationship nx>ny≧nz. Here, "ny=nz" includes not only the case where ny and nz are completely equal, but also the case where they are substantially equal. Therefore, there may be cases where ny<nz, as long as the effects of the present invention are not impaired. The Nz coefficient of the λ / 4 layer is preferably 0.9 to 3, more preferably 0.9 to 2.5, even more preferably 0.9 to 1.5, and particularly preferably 0.9 to 1.3.

[0024] The λ / 4 layer may be formed of any suitable material that satisfies the above-mentioned properties, and may be, for example, a stretched resin film or an oriented and solidified layer of a liquid crystal compound.

[0025] Examples of resins contained in the resin film include polycarbonate resins, polyester carbonate resins, polyester resins, polyvinyl acetal resins, polyarylate resins, cyclic olefin resins, cellulose resins, polyvinyl alcohol resins, polyamide resins, polyimide resins, polyether resins, polystyrene resins, and acrylic resins. These resins may be used alone or in combination (e.g., blends or copolymers). When the λ / 4 layer exhibits reverse dispersion wavelength characteristics, resin films containing polycarbonate resins or polyester carbonate resins (hereinafter sometimes simply referred to as polycarbonate resins) can be preferably used. When the λ / 4 layer exhibits flat wavelength dispersion characteristics, cyclic olefin resins, particularly norbornene resins, can be preferably used.

[0026] As the polycarbonate-based resin, any suitable polycarbonate-based resin can be used as long as the effects of the present invention can be obtained. For example, the polycarbonate-based resin contains structural units derived from a fluorene-based dihydroxy compound, structural units derived from an isosorbide-based dihydroxy compound, and structural units derived from at least one dihydroxy compound selected from the group consisting of alicyclic diols, alicyclic dimethanols, di-, tri-, or polyethylene glycols, and alkylene glycols or spiroglycols. Preferably, the polycarbonate-based resin contains structural units derived from a fluorene-based dihydroxy compound, structural units derived from an isosorbide-based dihydroxy compound, structural units derived from an alicyclic dimethanol and / or structural units derived from di-, tri-, or polyethylene glycol; more preferably, it contains structural units derived from a fluorene-based dihydroxy compound, structural units derived from an isosorbide-based dihydroxy compound, and structural units derived from di-, tri-, or polyethylene glycol. The polycarbonate-based resin may contain structural units derived from other dihydroxy compounds as needed. Details of polycarbonate-based resins that can be suitably used for the λ / 4 layer are described in, for example, JP 2014-10291 A, JP 2014-26266 A, JP 2015-212816 A, JP 2015-212817 A, and JP 2015-212818 A, and the descriptions of these publications are incorporated herein by reference.

[0027] Norbornene-based resins are resins polymerized using norbornene-based monomers as polymerization units. Examples of norbornene-based monomers include norbornene and its alkyl and / or alkylidene substituted derivatives such as 5-methyl-2-norbornene, 5-dimethyl-2-norbornene, 5-ethyl-2-norbornene, 5-butyl-2-norbornene, and 5-ethylidene-2-norbornene, as well as polar group-substituted derivatives thereof such as halogen; dicyclopentadiene; 2,3-dihydrodicyclopentadiene; Dimethanooctahydronaphthalene, its alkyl and / or alkylidene substituted derivatives, and polar group substituted derivatives such as halogen, for example, 6-methyl-1,4:5,8-dimethano-1,4,4a,5,6,7,8,8a-octahydronaphthalene, 6-ethyl-1,4:5,8-dimethano-1,4,4a,5,6,7,8,8a-octahydronaphthalene, 6-ethylidene-1,4:5,8-dimethano-1,4,4a,5,6, 7,8,8a-octahydronaphthalene, 6-chloro-1,4:5,8-dimethano-1,4,4a,5,6,7,8,8a-octahydronaphthalene, 6-cyano-1,4:5,8-dimethano-1,4,4a,5,6,7,8,8a-octahydronaphthalene, 6-pyridyl-1,4:5,8-dimethano-1,4,4a,5,6,7,8,8a-octahydronaphthalene, 6-methoxycarbonyl-1,4:5,8-dimethano and trimers and tetramers of cyclopentadiene, such as 4,9:5,8-dimethano-3a,4,4a,5,8,8a,9,9a-octahydro-1H-benzoindene and 4,11:5,10:6,9-trimethano-3a,4,4a,5,5a,6,9,9a,10,10a,11,11a-dodecahydro-1H-cyclopentaanthracene. The norbornene-based resin may be a copolymer of a norbornene-based monomer and another monomer.

[0028] Any appropriate stretching method and conditions (e.g., stretching temperature, stretching ratio, stretching direction) can be used for stretching the resin film. Specifically, various stretching methods such as free-end stretching, fixed-end stretching / free-end shrinkage, and fixed-end shrinkage can be used alone, simultaneously, or sequentially. Stretching can also be performed in various directions or dimensions, such as horizontal, vertical, thickness direction, and oblique direction. The stretching temperature is preferably within the range of ±20°C of the glass transition temperature (Tg) of the resin film.

[0029] The above-mentioned alignment-solidified layer of the liquid crystal compound is a layer in which the liquid crystal compound is aligned in a predetermined direction within the layer and the alignment state is fixed. The term "alignment-solidified layer" encompasses an alignment-solidified layer obtained by curing a liquid crystal monomer, as described below. Typically, rod-shaped liquid crystal compounds are aligned in the slow axis direction of the λ / 4 layer (homogeneous alignment). Examples of rod-shaped liquid crystal compounds include liquid crystal polymers and liquid crystal monomers. The liquid crystal compound is preferably polymerizable. If the liquid crystal compound is polymerizable, the alignment state of the liquid crystal compound can be fixed by aligning the liquid crystal compound and then polymerizing it.

[0030] The alignment and solidification layer of the liquid crystal compound (liquid crystal alignment and solidification layer) can be formed by performing an alignment treatment on the surface of a predetermined substrate, applying a coating liquid containing a liquid crystal compound to the surface to align the liquid crystal compound in a direction corresponding to the alignment treatment, and fixing the alignment state. Any appropriate alignment treatment can be used as the alignment treatment. Specific examples include mechanical alignment treatment, physical alignment treatment, and chemical alignment treatment. Specific examples of mechanical alignment treatment include rubbing treatment and stretching treatment. Specific examples of physical alignment treatment include magnetic field alignment treatment and electric field alignment treatment. Specific examples of chemical alignment treatment include oblique vapor deposition and photoalignment treatment. Any appropriate treatment conditions can be used for the various alignment treatments depending on the purpose.

[0031] The alignment of liquid crystal compounds is achieved by treating them at a temperature at which they exhibit a liquid crystal phase depending on the type of liquid crystal compound. By performing such temperature treatment, the liquid crystal compounds assume a liquid crystal state and are aligned in accordance with the alignment treatment direction on the substrate surface.

[0032] In one embodiment, the alignment state is fixed by cooling the liquid crystal compound aligned as described above. When the liquid crystal compound is polymerizable or crosslinkable, the alignment state is fixed by subjecting the liquid crystal compound aligned as described above to a polymerization treatment or a crosslinking treatment.

[0033] Any suitable liquid crystal polymer and / or liquid crystal monomer can be used as the liquid crystal compound. The liquid crystal polymer and the liquid crystal monomer can be used alone or in combination. Specific examples of liquid crystal compounds and methods for producing a liquid crystal alignment solidified layer are described in, for example, JP 2006-163343 A, JP 2006-178389 A, and WO 2018 / 123551 A. The descriptions in these publications are incorporated herein by reference.

[0034] When the λ / 4 layer is a stretched resin film, its thickness is, for example, 10 μm to 100 μm, preferably 10 μm to 70 μm, more preferably 10 μm to 60 μm, and even more preferably 20 μm to 50 μm. When the λ / 4 layer is a layer in which a liquid crystal compound is aligned and solidified, its thickness is, for example, 1 μm to 10 μm, preferably 1 μm to 8 μm, more preferably 1 μm to 6 μm, and even more preferably 1 μm to 4 μm.

[0035] <λ / 2 Layer> The in-plane retardation Re(550) of the λ / 2 layer 22 is, for example, 200 nm to 330 nm, may be 230 nm to 330 nm, may be 230 nm to 290 nm, or may be 250 nm to 280 nm.

[0036] The λ / 2 layer preferably exhibits an inverse dispersion wavelength characteristic in which the retardation value increases with the wavelength of the measurement light. The Re(450) / Re(550) of the λ / 2 layer may be, for example, 0.75 or more and less than 1, or 0.8 or more and 0.95 or less. Alternatively, for example, the λ / 2 layer may exhibit a flat wavelength dispersion characteristic in which the retardation value changes little with the wavelength of the measurement light. In this case, the Re(450) / Re(550) of the λ / 2 layer may be, for example, 0.99 to 1.03, and the Re(650) / Re(550) of the λ / 2 layer may be, for example, 0.98 to 1.02.

[0037] The λ / 2 layer preferably has a refractive index characteristic that satisfies the relationship nx>ny≧nz. Here, "ny=nz" includes not only the case where ny and nz are completely equal, but also the case where they are substantially equal. Therefore, there may be cases where ny<nz, as long as the effects of the present invention are not impaired. The Nz coefficient of the λ / 2 layer is preferably 0.9 to 3, more preferably 0.9 to 2.5, even more preferably 0.9 to 1.5, and particularly preferably 0.9 to 1.3.

[0038] The λ / 2 layer may be formed of any suitable material that satisfies the above-mentioned characteristics. The λ / 2 layer may be, for example, a stretched resin film or an oriented and solidified layer of a liquid crystal compound, and the material and method for forming the λ / 2 layer may be the same as those for forming the λ / 4 layer.

[0039] When the λ / 2 layer is a stretched resin film, its thickness is, for example, 20 μm to 200 μm, preferably 20 μm to 140 μm, more preferably 20 μm to 120 μm, and even more preferably 40 μm to 100 μm. When the λ / 2 layer is a layer in which a liquid crystal compound is aligned and solidified, its thickness is, for example, 2 μm to 20 μm, preferably 2 μm to 16 μm, more preferably 2 μm to 12 μm, and even more preferably 2 μm to 8 μm.

[0040] <Other Retardation Layers> Examples of other retardation layers include retardation layers whose refractive index characteristics can exhibit the relationship nz > nx = ny (so-called positive C plates). The thickness direction retardation Rth(550) of the positive C plate is preferably -20 nm to -200 nm, more preferably -30 nm to -180 nm, even more preferably -40 nm to -160 nm, and particularly preferably -50 nm to -140 nm. The positive C plate may have an Re(550) of, for example, less than 0.5 nm, 0.3 nm or less, or 0.1 nm or less.

[0041] The positive C plate can be formed from any appropriate material. The positive C plate is preferably composed of a film containing a liquid crystal material fixed in homeotropic alignment. The liquid crystal material (liquid crystal compound) that can be homeotropically aligned may be a liquid crystal monomer or a liquid crystal polymer. Specific examples of such liquid crystal compounds and methods for forming a positive C plate include the liquid crystal compounds and methods for forming the retardation layer described in paragraphs

[0020] to

[0028] of JP-A No. 2002-333642. In this case, the thickness of the positive C plate is preferably 0.5 μm to 5 μm.

[0042] [Protective Member] The protective member 30 includes a substrate. The protective member 30 may typically be a laminated film having a substrate 32 and a surface treatment layer 34. The protective member 30 having the surface treatment layer 34 may be disposed so that the surface treatment layer 34 is located on the outer side (the side opposite to the retardation member 20). For example, the surface treatment layer may be located on the outermost surface of the optical laminate.

[0043] The Re(550) of the protective member 30 may be, for example, 0.1 nm or more, 0.2 nm or more, 0.5 nm or more, 0.8 nm or more, or 1 nm or more, and may be, for example, 5.0 nm or less, or 4.0 nm or less. The Re(450) of the protective member 30 may be, for example, 0.1 nm to 5.0 nm or 0.1 nm to 4.0 nm. The Re(650) of the protective member 30 may be, for example, 0.1 nm to 5.0 nm or 0.1 nm to 4.0 nm. When a protective member having the above-mentioned in-plane retardation is used, the ellipticity of the circularly polarized light emitted from the retardation member may change (e.g., decrease) when passing through the protective member. However, by laminating both members so that the angle between the slow axis of the protective member, the slow axis of the retardation layer included in the retardation member, and the polarization direction of the linearly polarized light incident on the retardation member is within a predetermined range, the change in ellipticity can be suppressed.

[0044] The thickness of the protective member is preferably 10 μm to 80 μm, more preferably 15 μm to 60 μm, and even more preferably 20 μm to 50 μm.

[0045] The substrate 32 may be composed of any appropriate resin film. The substrate 32 may be a stretched or unstretched resin film. Examples of materials that form the main component of the resin film constituting the substrate 32 include cellulose-based resins such as triacetyl cellulose (TAC), polyester-based, polyvinyl alcohol-based, polycarbonate-based, polyamide-based, polyimide-based, polyethersulfone-based, polysulfone-based, polystyrene-based, cycloolefin-based resins such as polynorbornene, polyolefin-based, acrylic-based, and acetate-based resins. In one embodiment, the substrate 32 is preferably composed of an acrylic resin or a cellulose-based resin. For example, by forming a film of these resins by extrusion film formation, cast film formation, or the like, and then stretching the film as necessary, a substrate with small in-plane retardation and excellent surface smoothness can be obtained.

[0046] In one embodiment, when the resin film constituting the substrate is formed into a long shape, it may have a slow axis in a direction substantially parallel to the longitudinal direction or the width direction. For example, a protective member whose substrate contains a TAC-based resin may have a slow axis in a direction substantially parallel to the longitudinal direction. Furthermore, for example, a protective member whose substrate contains an acrylic-based resin may have a slow axis in a direction substantially parallel to the width direction. The Re(550) of the substrate may be, for example, 0.2 nm or more, 0.5 nm or more, 0.8 nm or more, or 1 nm or more, and may be, for example, 5.0 nm or less or 4.0 nm or less. Furthermore, the long substrate may have a variation in the slow axis angle in the width direction of ±10° or less, ±5° or less, or ±2° or less.

[0047] The thickness of the substrate 32 is preferably 5 μm to 80 μm, more preferably 10 μm to 60 μm, and even more preferably 20 μm to 45 μm.

[0048] The thickness of the surface treatment layer 34 is preferably 0.5 μm to 10 μm, more preferably 1 μm to 7 μm, and even more preferably 2 μm to 5 μm. The surface treatment layer 34 has, for example, a hard coat layer and an anti-reflection layer. The anti-reflection layer can be provided as the outermost layer of the surface treatment layer (the outermost surface of the protective member).

[0049] In one embodiment, the surface treatment layer has substantially no in-plane retardation (e.g., Re(550) is less than 0.5 nm, or 0.2 nm or less, or 0.1 nm or less). Therefore, the in-plane retardation of the substrate may be dominant in the in-plane retardation of the protective member. In one embodiment, the in-plane retardation of the substrate can be considered to be the in-plane retardation of the protective member. Furthermore, the slow axis direction of the substrate can be considered to be the slow axis direction of the protective member.

[0050] The hard coat layer is typically formed by applying a hard coat layer-forming material to the substrate 32 and curing the applied layer. The hard coat layer-forming material typically includes a curable compound as a layer-forming component. Examples of the curing mechanism of the curable compound include heat-curing and photo-curing. Examples of the curable compound include monomers, oligomers, and prepolymers. Preferably, a polyfunctional monomer or oligomer is used as the curable compound. Examples of the polyfunctional monomer or oligomer include a monomer or oligomer having two or more (meth)acryloyl groups, a urethane (meth)acrylate or a urethane (meth)acrylate oligomer, an epoxy-based monomer or oligomer, and a silicone-based monomer or oligomer.

[0051] The thickness of the hard coat layer is preferably 0.5 μm to 10 μm, more preferably 1 μm to 7 μm, and even more preferably 2 μm to 5 μm.

[0052] The antireflection layer preferably has a laminated structure including a high refractive index layer and a low refractive index layer, in this order from the substrate 32 side.

[0053] For example, the high refractive index layer may be composed of a high refractive index resin (e.g., a refractive index of 1.55 or more measured at a wavelength of 550 nm). In this case, the high refractive index layer may typically be a coating layer. Alternatively, the high refractive index layer may be composed of an inorganic film. In this case, the high refractive index layer may typically be formed by physical vapor deposition such as vacuum deposition or sputtering, or chemical vapor deposition.

[0054] The thickness of the high refractive index layer is preferably 10 nm to 200 nm, and more preferably 20 nm to 150 nm.

[0055] The thickness of the low refractive index layer is preferably 10 nm to 200 nm, and more preferably 20 nm to 150 nm.

[0056] The low refractive index layer can be obtained, for example, by applying a coating liquid for forming a low refractive index layer, drying the coating, and curing the resulting coating. The coating liquid for forming a low refractive index layer may contain, for example, a resin component (curable compound), a fluorine-containing additive, hollow particles, solid particles, a solvent, and the like, and can be obtained, for example, by mixing these.

[0057] The curing mechanism of the resin component (curable compound) contained in the coating liquid for forming the low refractive index layer can be, for example, a thermosetting type or a photocurable type. As the resin component, for example, a curable compound having at least one of an acrylate group and a methacrylate group is used, and examples thereof include oligomers or prepolymers such as acrylates or methacrylates of polyfunctional compounds such as silicone resins, polyester resins, polyether resins, epoxy resins, urethane resins, alkyd resins, spiroacetal resins, polybutadiene resins, polythiolpolyene resins, and polyhydric alcohols. These can be used alone or in combination of two or more types.

[0058] The resin component may also contain a reactive diluent having at least one of an acrylate group and a methacrylate group. Examples of the reactive diluent include those described in JP 2008-88309 A, including monofunctional acrylates, monofunctional methacrylates, polyfunctional acrylates, and polyfunctional methacrylates. From the viewpoint of achieving excellent hardness, trifunctional or higher acrylates and trifunctional or higher methacrylates are preferably used as the reactive diluent. Examples of reactive diluents include butanediol glycerin ether diacrylate, acrylates of isocyanuric acid, and methacrylates of isocyanuric acid. These may be used alone or in combination of two or more. A curing agent may be used to cure the resin component. Examples of the curing agent include known polymerization initiators (e.g., thermal polymerization initiators, photopolymerization initiators, etc.).

[0059] The fluorine-containing additive may be, for example, an organic compound containing fluorine or an inorganic compound containing fluorine. Examples of fluorine-containing organic compounds include fluorine-containing antifouling coating agents, fluorine-containing acrylic compounds, and fluorine-silicon-containing acrylic compounds. Commercially available fluorine-containing organic compounds can be used. Specific examples of commercially available products include "KY-1203" manufactured by Shin-Etsu Chemical Co., Ltd. and "Megafac" manufactured by DIC Corporation. The content of the fluorine-containing additive may be, for example, 0.05 parts by weight or more, 0.1 parts by weight or more, 0.15 parts by weight or more, 0.20 parts by weight or more, or 0.25 parts by weight or more, or 20 parts by weight or less, 15 parts by weight or less, 10 parts by weight or less, 5 parts by weight or less, or 3 parts by weight or less, relative to 100 parts by weight of the resin component.

[0060] Examples of hollow particles that can be used include silica particles, acrylic particles, and acrylic-styrene copolymer particles. Commercially available hollow silica particles (e.g., products manufactured by JGC Catalysts and Chemicals Industries, Ltd. under the trade names "Suluria 5320" and "Suluria 4320") can be used. The weight-average particle diameter of the hollow particles can be, for example, 30 nm or more, 40 nm or more, 50 nm or more, 60 nm or more, or 70 nm or more, or 150 nm or less, 140 nm or less, 130 nm or less, 120 nm or less, or 110 nm or less. The shape of the hollow particles is not particularly limited, but is preferably approximately spherical. Specifically, the aspect ratio of the hollow particles is preferably 1.5 or less. The content of the hollow particles may be, for example, 30 parts by weight or more, 50 parts by weight or more, 70 parts by weight or more, 90 parts by weight or more, or 100 parts by weight or more, or 300 parts by weight or less, 270 parts by weight or less, 250 parts by weight or less, 200 parts by weight or less, or 180 parts by weight or less, relative to 100 parts by weight of the resin component.

[0061] Examples of the solid particles include silica particles, zirconia particles, and titania particles. Commercially available solid silica particles (e.g., products manufactured by Nissan Chemical Industries, Ltd. under the trade names "MEK-2140Z-AC," "MIBK-ST," and "IPA-ST") can be used. The weight-average particle diameter of the solid particles may be, for example, 5 nm or more, 10 nm or more, 15 nm or more, 20 nm or more, or 25 nm or more, or 330 nm or less, 250 nm or less, 200 nm or less, 150 nm or less, or 100 nm or less. The shape of the hollow particles is not particularly limited, but is preferably approximately spherical. Specifically, the aspect ratio of the hollow particles is preferably 1.5 or less. The content of the solid particles may be, for example, 5 parts by weight or more, 10 parts by weight or more, 15 parts by weight or more, 20 parts by weight or more, or 25 parts by weight or more, and may be 150 parts by weight or less, 120 parts by weight or less, 100 parts by weight or less, or 80 parts by weight or less, relative to 100 parts by weight of the resin component.

[0062] Any appropriate solvent can be used as the solvent. Examples of the solvent include alcohols such as methanol, ethanol, isopropyl alcohol, butanol, TBA (tertiary butyl alcohol), and 2-methoxyethanol; ketones such as acetone, methyl ethyl ketone, MIBK (methyl isobutyl ketone), and cyclopentanone; esters such as methyl acetate, ethyl acetate, butyl acetate, and PMA (propylene glycol monomethyl ether acetate); ethers such as diisopropyl ether and propylene glycol monomethyl ether; glycols such as ethylene glycol and propylene glycol; cellosolves such as ethyl cellosolve and butyl cellosolve; aliphatic hydrocarbons such as hexane, heptane, and octane; and aromatic hydrocarbons such as benzene, toluene, and xylene. These solvents may be used alone or in combination of two or more. The content of the solvent may be, for example, such that the weight of the solids relative to the total weight of the coating liquid for forming the low refractive index layer is, for example, 0.1 wt % or more, 0.3 wt % or more, 0.5 wt % or more, 1.0 wt % or more, or 1.5 wt % or more, or may be 20 wt % or less, 15 wt % or less, 10 wt % or less, 5 wt % or less, or 3 wt % or less.

[0063] The coating liquid for forming the low refractive index layer can be applied by known coating methods such as fountain coating, die coating, spin coating, spray coating, gravure coating, roll coating, and bar coating. The drying temperature of the coating film is, for example, 30°C to 200°C, and the drying time is, for example, 30 to 90 seconds. The coating film can be cured by, for example, heating or light irradiation (typically, ultraviolet irradiation). A high-pressure mercury lamp, for example, is used as a light source for light irradiation. The dose of ultraviolet irradiation is 50 mJ / cm as an integrated exposure dose at an ultraviolet wavelength of 365 nm. ２ ~500 mJ / cm ２ It is preferable that:

[0064] [Absorptive Polarizing Member] The absorptive polarizing member may typically include a resin film (sometimes referred to as an absorptive polarizing film) containing a dichroic material. The thickness of the absorptive polarizing film is, for example, 1 μm or more and 20 μm or less, and may be 2 μm or more and 15 μm or less, 12 μm or less, 10 μm or less, 8 μm or less, or 5 μm or less. A protective layer may be provided on one or both sides of the absorptive polarizing film.

[0065] The absorptive polarizing film may be made from a single layer of resin film or may be made from a laminate of two or more layers.

[0066] When the absorptive polarizing film is produced from a single-layer resin film, for example, an absorptive polarizing film can be obtained by subjecting a hydrophilic polymer film such as a polyvinyl alcohol (PVA)-based film, a partially formalized PVA-based film, or a partially saponified ethylene-vinyl acetate copolymer-based film to a dyeing treatment with iodine or a dichroic substance such as a dichroic dye, a stretching treatment, etc. Among these, an absorptive polarizing film obtained by dyeing a PVA-based film with iodine and uniaxially stretching it is preferred.

[0067] The dyeing with iodine is carried out, for example, by immersing the PVA-based film in an aqueous iodine solution. The stretching ratio of the uniaxial stretching is preferably 3 to 7 times. The stretching may be carried out after the dyeing treatment or while dyeing. Alternatively, the PVA-based film may be dyed after stretching. If necessary, the PVA-based film may be subjected to a swelling treatment, a crosslinking treatment, a washing treatment, a drying treatment, or the like.

[0068] Examples of laminates produced using the two or more layer laminate include a laminate of a resin substrate and a PVA-based resin layer (PVA-based resin film) laminated on the resin substrate, and a laminate of a resin substrate and a PVA-based resin layer formed by coating on the resin substrate. An absorptive polarizing film obtained using a laminate of a resin substrate and a PVA-based resin layer formed by coating on the resin substrate can be produced, for example, by applying a PVA-based resin solution to the resin substrate and drying the solution to form a PVA-based resin layer on the resin substrate, thereby obtaining a laminate of the resin substrate and the PVA-based resin layer, and then stretching and dyeing the laminate to convert the PVA-based resin layer into an absorptive polarizing film. In this embodiment, a polyvinyl alcohol-based resin layer containing a halide and a polyvinyl alcohol-based resin is preferably formed on one side of the resin substrate. The stretching typically involves immersing the laminate in an aqueous boric acid solution to stretch it. Furthermore, the stretching may further include in-air stretching of the laminate at a high temperature (e.g., 95°C or higher) before stretching in the boric acid aqueous solution, as necessary. In addition, in this embodiment, the laminate is preferably subjected to a drying shrinkage treatment in which the laminate is heated while being transported in the longitudinal direction, thereby shrinking the laminate by 2% or more in the width direction. Typically, the manufacturing method of this embodiment includes subjecting the laminate to an auxiliary in-air stretching treatment, a dyeing treatment, an underwater stretching treatment, and a drying shrinkage treatment, in this order. By introducing auxiliary stretching, it is possible to increase the crystallinity of the PVA, even when the PVA is coated on a thermoplastic resin, thereby achieving high optical properties. Furthermore, by simultaneously increasing the orientation of the PVA in advance, problems such as a decrease in orientation or dissolution of the PVA when immersed in water in the subsequent dyeing or stretching steps can be prevented, thereby achieving high optical properties. Furthermore, when the PVA-based resin layer is immersed in a liquid, the disordering of the polyvinyl alcohol molecules and the decrease in orientation can be suppressed compared to when the PVA-based resin layer does not contain a halide. This can improve the optical properties of the absorptive polarizing film obtained through treatment steps in which the laminate is immersed in a liquid, such as a dyeing treatment and an underwater stretching treatment.Furthermore, the optical properties can be improved by shrinking the laminate in the width direction through a drying shrinkage treatment.The obtained resin substrate / absorptive polarizing film laminate may be used as is (i.e., the resin substrate may be used as a protective layer for the absorptive polarizing film), or any suitable protective layer may be laminated depending on the purpose on the surface obtained by peeling the resin substrate from the resin substrate / absorptive polarizing film laminate or on the surface opposite to the peeled surface. Details of such methods for producing an absorptive polarizing film are described in, for example, JP-A-2012-73580 and Japanese Patent No. 6,470,455. The entire disclosures of these publications are incorporated herein by reference.

[0069] The crossed transmittance (Tc) of the absorptive polarizing element (absorptive polarizing film) is preferably 0.5% or less, more preferably 0.1% or less, and even more preferably 0.05% or less. The single transmittance (Ts) of the absorptive polarizing element (absorptive polarizing film) is, for example, 41.0% to 45.0%, and preferably 42.0% or more. The polarization degree (P) of the absorptive polarizing element (absorptive polarizing film) is, for example, 99.0% to 99.997%, and preferably 99.9% or more.

[0070] [Reflective Polarizing Element] A reflective polarizing element transmits light polarized parallel to its transmission axis (typically, linearly polarized light) while maintaining its polarization state, and can reflect light polarized in other states (typically, light polarized perpendicular to its transmission axis). A reflective polarizing element is typically composed of a film having a multilayer structure (sometimes referred to as a reflective polarizing film). In this case, the thickness of the reflective polarizing element is, for example, 10 μm to 150 μm, preferably 20 μm to 100 μm, and more preferably 30 μm to 60 μm.

[0071] Commercially available reflective polarizing films include, for example, "DBEF" and "APF" manufactured by 3M, and "APCF" manufactured by Nitto Denko Corporation.

[0072] The crossed transmittance (Tc) of the reflective polarizing element (reflective polarizing film) can be, for example, 0.01% to 3%. The single transmittance (Ts) of the reflective polarizing element (reflective polarizing film) can be, for example, 43% to 49%, preferably 45% to 47%. The polarization degree (P) of the reflective polarizing element (reflective polarizing film) can be, for example, 92% to 99.99%.

[0073] A-2. Lamination of Retardation Member and Protective Member The retardation member and the protective member are laminated such that the angle between the polarization direction of linearly polarized light incident on the first main surface of the retardation member and converted into circularly polarized light and the slow axis of the protective member is, for example, 15° or less (in other words, within the range of 0°±15°) or 75° to 105° (in other words, within the range of 90°±15°). The angle is preferably 10° or less, more preferably 5° or less, even more preferably 3° or less, or preferably 80° to 100°, more preferably 85° to 95°, and even more preferably 87° to 93°.

[0074] When the retardation member of the above-described configuration 1 is used, lamination of the retardation member and the protective member may include laminating the λ / 4 layer and the protective member so that the angle between the slow axis of the λ / 4 layer and the slow axis of the protective member is, for example, 30° to 60° (in other words, within a range of 45°±15°), preferably 35° to 55°, more preferably 40° to 50°, and even more preferably 42° to 48°. In the optical laminate obtained by laminating as described above, the angle between the polarization direction of linearly polarized light (linearly polarized light to be converted into circularly polarized light) incident on the first main surface of the retardation member and the slow axis of the λ / 4 layer is, for example, 40° to 50°, 42° to 48°, or about 45°, the angle between the slow axis of the λ / 4 layer and the slow axis of the protective member is, for example, 30° to 60°, preferably 35° to 55°, more preferably 40° to 50°, and even more preferably 42° to 48°, and the angle between the polarization direction of the linearly polarized light and the slow axis of the protective member can be, for example, 15° or less or 75° to 105°. According to the optical laminate obtained by stacking the components so as to have the above-described axial angles, as shown in FIG. 5 , linearly polarized light LP1 incident on the phase difference component 20 (substantially, the λ / 4 layer 21) from the first main surface 20a side is emitted as circularly polarized light CP1 from the second main surface 20b side, and can be transmitted through the protective component 30 without significantly changing its ellipticity and emitted as circularly polarized light CP2 (in the figure, arrow a represents the slow axis direction of the protective component 30, arrow b represents the polarization direction of linearly polarized light LP1 incident on the phase difference component 20 from the first main surface 20a side, and the angle formed by arrows a and b is 15° or less).

[0075] The lamination of the retardation member and the protective member in configuration 1 may include laminating the λ / 4 layer and the protective member, both of which are in a sheet form (so-called sheet to sheet), or may include laminating the λ / 4 layer and the protective member, both of which are in a long shape, continuously with their longitudinal directions aligned (so-called roll to roll).

[0076] The planar shape of the sheet-shaped λ / 4 layer and protective member may be, for example, rectangular (including square). The "rectangular" shape may have chamfered or notched corners. The sheet-shaped λ / 4 layer and protective member may be obtained by punching out a long sheet-shaped λ / 4 layer and protective member, respectively.

[0077] In the case where the variation in the orientation angle in the width direction of the long λ / 4 layer and / or protective member is large, sheet-to-sheet lamination may be advantageous from the viewpoint of precise axis adjustment. On the other hand, in the case where the variation in the orientation angle in the width direction of the long λ / 4 layer and / or protective member is small, roll-to-roll lamination may be advantageous from the viewpoint of manufacturing efficiency.

[0078] The long λ / 4 layer and protective member may have a slow axis in any of the longitudinal direction, the width direction, and the oblique direction. In one embodiment, the long protective member may have a slow axis in a direction substantially parallel to the longitudinal direction or the width direction. The long λ / 4 layer may have a slow axis in the same direction as the stretching direction of the resin film constituting the λ / 4 layer or the alignment direction of the liquid crystal material constituting the λ / 4 layer.

[0079] For example, as shown in FIG. 6, sheet-to-sheet lamination can be performed by laminating a rectangular λ / 4 layer 21s obtained by punching a long λ / 4 layer 21r so that its slow axis direction (arrow c) is approximately perpendicular to or approximately parallel to the side direction, and a rectangular protective member 30s obtained by punching a long protective member 30r so that its slow axis direction (arrow a) forms an angle with the side direction of, for example, 30° to 60°, preferably 35° to 55°, more preferably 40° to 50°, and even more preferably 42° to 48°.

[0080] Furthermore, for example, sheet-to-sheet lamination can be performed by laminating a rectangular λ / 4 layer 21s obtained by punching out a long λ / 4 layer 21r so that its slow axis direction (arrow c) forms an angle of, for example, 30° to 60°, preferably 35° to 55°, more preferably 40° to 50°, and even more preferably 42° to 48° with the side direction, as shown in FIG. 7 , and a rectangular protective member 30s obtained by punching out a long protective member 30r so that its slow axis direction (arrow a) is approximately perpendicular to or approximately parallel to the side direction.

[0081] The roll-to-roll lamination can be performed by, for example, laminating, in a roll-to-roll manner, a long λ / 4 layer having a slow axis in an oblique direction, preferably at an angle of, for example, 30° to 60°, preferably 35° to 55°, more preferably 40° to 50°, and even more preferably 42° to 48° relative to the longitudinal direction, and a long protective member having a slow axis in a direction approximately parallel to the longitudinal direction or the width direction.

[0082] When the retardation member of the configuration 1 includes a retardation layer other than the λ / 4 layer (for example, a positive C plate), the stacking order of each member or layer is not limited as long as an optical laminate having the desired configuration is obtained. Therefore, the above description of "laminating a retardation member and a protective member" is not limited to an embodiment in which a separately prepared retardation member and a protective member are laminated, as long as an optical laminate having the desired configuration is obtained, and may include an embodiment in which some of the retardation layers constituting the retardation member and the protective member are laminated, and the remaining retardation layers are laminated on the resulting laminate. Furthermore, the description of "laminating a λ / 4 layer and a protective member" may include not only an embodiment in which the λ / 4 layer and the protective member are laminated adjacent to each other via an adhesive layer, but also an embodiment in which a retardation member including a λ / 4 layer and another retardation layer and a protective member are laminated so that another retardation layer is interposed between the λ / 4 layer and the protective member.

[0083] When the retardation member of Configuration 2 is used, lamination of the retardation member and the protective member includes laminating the λ / 4 layer and the protective member so that the angle between the slow axis of the λ / 4 layer and the slow axis of the protective member is, for example, 60° to 90° (in other words, within a range of 75°±15°), preferably 65° to 85°, more preferably 70° to 80°, and even more preferably 72° to 78°, or for example, 0° to 30° (in other words, within a range of 15°±15°), preferably 5° to 25°, more preferably 10° to 20°, and even more preferably 12° to 18°. In the optical laminate obtained by laminating in this manner, the angle between the polarization direction of linearly polarized light (linearly polarized light to be converted into circularly polarized light) incident from the first main surface of the retarder and the slow axis of the λ / 2 layer is, for example, 55° to 85°, 70° to 80°, 72° to 78°, or about 75°, and the angle between the polarization direction of the linearly polarized light and the slow axis of the λ / 4 layer is, for example, 5° to 35°, 10° to 20°, 12° to 18°, or about 15°, or the angle between the polarization direction of the linearly polarized light and the slow axis of the λ / 2 layer is, for example, 5° to 35°, 10° to 20°, 12° to 18°, or about 15°, and the angle between the polarization direction of the linearly polarized light and the slow axis of the λ / 4 ... 55° to 85°, 70° to 80°, 72° to 78°, or about 75°, The angle between the slow axis of the λ / 4 layer and the slow axis of the protective member is, for example, 60° to 90° or 0° to 30°, and the angle between the polarization direction of the linearly polarized light and the slow axis of the protective member can be, for example, 15° or less or 75° to 105°. By stacking the components so as to achieve the above-mentioned axis angles, linearly polarized light incident on the retardation component from the first main surface side (in other words, the λ / 2 layer side) is emitted as circularly polarized light from the second main surface side (in other words, the λ / 4 layer side), and can be transmitted through the protective member without significantly changing its ellipticity and emitted as circularly polarized light.

[0084] The retardation member and the protective member of the configuration 2 may be laminated sheet to sheet or roll to roll. The same explanation as above can be applied to the sheet to sheet lamination and the roll to roll lamination, respectively.

[0085] For example, sheet-to-sheet lamination may include preparing sheet-like members and laminating them via an adhesive layer so that they have a desired axial angle. The sheet-like retardation member may be produced by punching out a long-length retardation member obtained by laminating each long-length retardation layer in a roll-to-roll manner, or by laminating each sheet-like retardation layer obtained by punching out each long-length retardation layer in a sheet-to-sheet manner.

[0086] In the lamination of the retardation member and the protective member of the second configuration, the order of lamination of each member or layer is not limited as long as an optical laminate having the desired configuration is obtained. For example, after laminating a λ / 2 layer, a λ / 4 layer, and optionally other retardation layers to obtain a retardation member, the retardation member and the protective member may be laminated. Alternatively, some of the layers constituting the retardation member (e.g., a λ / 4 layer and a positive C plate) and the protective member may be laminated, and then the remaining retardation layer (e.g., a λ / 2 layer) may be laminated. Therefore, the above-mentioned phrase "laminating a retardation member and a protective member" is not limited to an embodiment in which a separately prepared retardation member and a protective member are laminated, as long as an optical laminate having the desired configuration is obtained. It may also include an embodiment in which some of the retardation layers constituting the retardation member and the protective member are laminated, and the remaining retardation layer is laminated on the resulting laminate. Furthermore, the phrase "laminating a λ / 4 layer and a protective member" may include an embodiment in which a retardation member containing a λ / 4 layer and other retardation layers is laminated with a protective member.

[0087] The lamination of the retardation member and the protective member and the lamination of each retardation layer constituting the retardation member are typically performed via an adhesive layer. The adhesive layer may be a pressure-sensitive adhesive layer or an adhesive layer. The lamination of the retardation member and the protective member is preferably performed via a pressure-sensitive adhesive layer.

[0088] In one embodiment, a pressure-sensitive adhesive layer is provided on one surface of the protective member (typically, the surface opposite to the side on which the surface treatment layer of the substrate is provided), and the retardation member and the protective member are laminated via the pressure-sensitive adhesive layer. From the viewpoint of reducing loss due to loss during pressure-sensitive adhesive layer formation, it may be more advantageous to provide the pressure-sensitive adhesive layer on the protective member than to provide the pressure-sensitive adhesive layer on the retardation member.

[0089] The pressure-sensitive adhesive layer may be composed of any appropriate pressure-sensitive adhesive. Specific examples include acrylic pressure-sensitive adhesives, rubber pressure-sensitive adhesives, silicone pressure-sensitive adhesives, polyester pressure-sensitive adhesives, urethane pressure-sensitive adhesives, epoxy pressure-sensitive adhesives, and polyether pressure-sensitive adhesives. Among these, acrylic pressure-sensitive adhesives are preferred. By adjusting the type, number, combination, and compounding ratio of monomers forming the base resin of the pressure-sensitive adhesive, as well as the compounding amount of cross-linking agent, reaction temperature, reaction time, etc., a pressure-sensitive adhesive having desired properties according to the purpose can be prepared. The base resin of the pressure-sensitive adhesive may be used alone or in combination of two or more types. An acrylic resin is preferably used as the base resin.

[0090] The thickness of the pressure-sensitive adhesive layer is, for example, 12 μm or more, preferably 15 μm or more, and for example, 100 μm or less, preferably 80 μm or less.

[0091] A-3. Lamination of Polarizing Members Lamination of a retardation member and a polarizing member is typically performed by laminating a polarizing member on the first main surface side of a retardation member so that the polarizing member provides linearly polarized light that is converted into circularly polarized light when incident on the first main surface of the retardation member. This makes it possible to suitably obtain an optical laminate such as the one shown in FIG.

[0092] For example, when using a retardation member of configuration 1, the lamination can be performed so that the angle between the slow axis of the λ / 4 layer and the polarization axis of the polarizing member is, for example, 40° to 50°, 42° to 48°, or approximately 45°. The polarization axis can be, for example, the transmission axis of an absorptive polarizing member or the reflection axis of a reflective polarizing member. In the optical laminate obtained by lamination in this manner, the angle between the polarization axis of the polarizing member and the slow axis of the λ / 4 layer is as described above, the angle between the slow axis of the λ / 4 layer and the slow axis of the protective member is, for example, 30° to 60°, preferably 35° to 55°, more preferably 40° to 50°, and even more preferably 42° to 48°, and the angle between the polarization axis of the polarizing member and the slow axis of the protective member can be, for example, 15° or less or 75° to 105°. According to the optical laminate obtained by stacking each component so as to obtain the above-described axial angle, as shown in FIG. 8, linearly polarized light LP1 that has passed through or been reflected by the polarizing component 10 enters the phase difference component 20 (essentially, the λ / 4 layer 21) from the first main surface 20a side and is emitted as circularly polarized light CP1 from the second main surface 20b side, and can pass through the protective component 30 without significantly changing its ellipticity and be emitted as circularly polarized light CP2 (in the figure, arrow a represents the slow axis direction of the protective component 30, arrow d represents the polarization axis direction of the polarizing component 10, and the angle between arrows a and d is 15° or less).

[0093] Furthermore, for example, when a retardation member of configuration 2 is used, the lamination can be performed so that the angle between the slow axis of the λ / 2 layer and the polarization axis of the polarizing member is, for example, 5° to 35°, 10° to 20°, 12° to 18°, or about 15°, and the angle between the slow axis of the λ / 4 layer and the polarization axis of the polarizing member is, for example, 55° to 85°, 70° to 80°, 72° to 78°, or about 75°. Alternatively, the lamination can be performed so that the angle between the slow axis of the λ / 2 layer and the polarization axis of the polarizing member is, for example, 55° to 85°, 70° to 80°, 72° to 78°, or about 75°, and the angle between the slow axis of the λ / 4 layer and the polarization axis of the polarizing member is, for example, 5° to 35°, 10° to 20°, 12° to 18°, or about 15°. In the optical laminate obtained by laminating in this manner, the angle between the polarization axis of the polarizing member and the slow axis of the λ / 2 layer or λ / 4 layer is as described above, and the angle between the slow axis of the λ / 4 layer and the slow axis of the protective member is, for example, 60° to 90°, preferably 65° to 85°, more preferably 70° to 80°, and even more preferably 72° to 78°, or for example, 0° to 30°, preferably 5° to 25°, more preferably 10° to 20°, and even more preferably 12° to 18°, and the angle between the polarization axis of the polarizing member and the slow axis of the protective member can be, for example, 15° or less or 75° to 105°. According to the optical laminate obtained by stacking each component so that the axial angle is as described above, linearly polarized light LP1 that has passed through the absorptive polarizing component or been reflected by the reflective polarizing component enters the phase difference component from the first main surface side (λ / 2 layer side) and exits from the second main surface side (λ / 4 layer side) as circularly polarized light CP1, and can pass through the protective component without significantly changing its ellipticity and exit as circularly polarized light CP2.

[0094] The lamination of the retardation member and the polarizing member may be performed sheet-to-sheet or roll-to-roll. The sheet-to-sheet lamination and roll-to-roll lamination are as described above for the lamination of the retardation member and the protective member. For example, a long λ / 4 layer and / or λ / 2 layer having a slow axis in an oblique direction and a polarizing member having a polarization axis in the longitudinal or width direction can be laminated roll-to-roll. Also, for example, each retardation layer or retardation member punched into a rectangular shape so that the slow axis forms a predetermined angle with the side direction can be laminated sheet-to-sheet with the polarizing member.

[0095] The phase difference member and the polarizing member are typically laminated via an adhesive layer. The adhesive layer may be a pressure-sensitive adhesive layer or an adhesive layer, and is preferably a pressure-sensitive adhesive layer. In addition, in laminating the phase difference member and the polarizing member, as in laminating the phase difference member and the protective member, the lamination order of each member or layer is not limited as long as an optical laminate having the desired configuration is obtained. Therefore, the above description of "laminating the phase difference member and the polarizing member" is not limited to an embodiment in which a separately prepared phase difference member and a polarizing member are laminated, as long as an optical laminate having the desired configuration is obtained, and may include an embodiment in which a part of the phase difference layer constituting the phase difference member and the polarizing member are laminated, and the remaining phase difference layer is laminated on the obtained laminate.

[0096] B. Display System FIG. 9 is a schematic diagram showing the general configuration of an example of a display system to which the optical laminate obtained by the manufacturing method described in Section A can be applied. FIG. 9 schematically illustrates the arrangement and shape of each component of a display system 2. The display system 2 includes a display element 12, a reflective polarizing element 14, a first lens unit 16, a half mirror 18, a first phase difference element 23a, a second phase difference element 23b, and a second lens unit 24. The reflective polarizing element 14 is disposed in front of the display surface 12a of the display element 12 and can reflect light emitted from the display element 12. The first lens unit 16 is disposed on the optical path between the display element 12 and the reflective polarizing element 14, and the half mirror 18 is disposed between the display element 12 and the first lens unit 16. The first phase difference element 23a is disposed on the optical path between the display element 12 and the half mirror 18, and the second phase difference element 23b is disposed on the optical path between the half mirror 18 and the reflective polarizing element 14. The first phase difference member 23a and the second phase difference member 23b can convert linearly polarized light into circularly polarized light or circularly polarized light into linearly polarized light, respectively. Although not shown, an absorptive polarizing member may be disposed between the reflective polarizing member 14 and the second lens portion 24 from the viewpoint of improving visibility. In this case, the reflection axis of the reflective polarizing member 14 and the absorption axis of the absorptive polarizing member may be disposed approximately parallel to each other, and the transmission axis of the reflective polarizing member 14 and the transmission axis of the absorptive polarizing member may be disposed approximately parallel to each other.

[0097] The half mirror or the components arranged forward from the first lens unit (in the illustrated example, the half mirror 18, first lens unit 16, second phase difference member 23b, reflective polarizing member 14, and second lens unit 24) may be collectively referred to as the lens unit (lens unit 4).

[0098] The display element 12 is, for example, a liquid crystal display or an organic EL display, and has a display surface 12 a for displaying an image. The light emitted from the display surface 12 a passes through, for example, a polarizing member (typically, a polarizing film) that may be included in the display element 12, and is converted into first linearly polarized light.

[0099] The first linearly polarized light incident on the first phase difference member 23 a is converted into first circularly polarized light. The first phase difference member 23 a may be provided integrally with the display element 12. For example, the first phase difference member 23 a may be provided integrally with a polarizing member that may be included in the display element 12.

[0100] The half mirror 18 transmits the light emitted from the display element 12 and reflects the light reflected by the reflective polarizing member 14 back toward the reflective polarizing member 14. The half mirror 18 is provided integrally with the first lens portion 16.

[0101] The second phase difference member 23b can transmit light reflected by the reflective polarizing member 14 and the half mirror 18 through the reflective polarizing member 14. The second phase difference member 23b may be provided integrally with the first lens portion 16 or the second lens portion 24. In the latter case, the second phase difference member 23b can be provided integrally with the second lens portion 24 together with the reflective polarizing member 14.

[0102] The first circularly polarized light emitted from the first phase difference member 23a passes through the half mirror 18 and the first lens unit 16 and is converted into the second linearly polarized light by the second phase difference member 23b. The second linearly polarized light emitted from the second phase difference member 23b is reflected toward the half mirror 18 without passing through the reflective polarizing member 14. At this time, the polarization direction of the second linearly polarized light incident on the reflective polarizing member 14 is the same as the reflection axis of the reflective polarizing member. Therefore, the second linearly polarized light incident on the reflective polarizing member 14 is reflected by the reflective polarizing member 14.

[0103] The second linearly polarized light reflected by the reflective polarizing element 14 is converted into second circularly polarized light by the second phase difference element 23b, and the second circularly polarized light emitted from the second phase difference element 23b passes through the first lens unit 16 and is reflected by the half mirror 18. The circularly polarized light reflected by the half mirror 18 passes through the first lens unit 16 and is converted into third linearly polarized light by the second phase difference element 23b. The third linearly polarized light is transmitted through the reflective polarizing element 14. At this time, the polarization direction of the third linearly polarized light incident on the reflective polarizing element 14 is the same direction as the transmission axis of the reflective polarizing element. Therefore, the third linearly polarized light incident on the reflective polarizing element 14 is transmitted through the reflective polarizing element.

[0104] The light transmitted through the reflective polarizing member 14 passes through the second lens portion 24 and enters the user's eye 26 .

[0105] For example, the absorption axis of the polarizing member included in the display element 12 and the reflection axis of the reflective polarizing member 14 may be arranged substantially parallel to each other or may be arranged substantially perpendicular to each other.

[0106] In one embodiment, the optical laminate obtained by the manufacturing method described in Section A can be applied to the display system 2 as an optical laminate including the first phase difference member 23a. In this embodiment, the optical laminate is disposed behind the half mirror 18 so that the second main surface 20b of the phase difference member 20 faces the half mirror 18, thereby allowing the phase difference member 20 to function as the first phase difference member 23a. For example, as shown in FIG. 10 , a display system in which the first phase difference member 23a is integrated into the display element 12 can be configured by bonding the optical laminate 100B to the member 13 constituting the display element with the adhesive layer 40. In this display system, the polarizing member 10 is an absorptive polarizing member that can be included in the display element 12, and light emitted from the polarizing member 10 becomes first linearly polarized light. The first linearly polarized light is converted into first circularly polarized light by the first phase difference member 23a, and can maintain high ellipticity even after passing through the protective member 30. As a result, polarization disturbance in the display system can be suppressed, improving visibility.

[0107] In one embodiment, the optical laminate obtained by the manufacturing method described in Section A can be applied to the display system 2 as an optical laminate including the second phase difference member 23b. In this embodiment, the optical laminate is disposed in front of the half mirror 18 (but behind the second lens unit 24) so ​​that the second main surface 20b of the phase difference member 20 faces the half mirror 18, thereby allowing the phase difference member 20 to function as the second phase difference member 23b. For example, as shown in FIG. 11 , by bonding the optical laminate 100B to the second lens unit 24 with a pressure-sensitive adhesive layer 40, a display system can be configured in which the second phase difference member 23b is integrated into the second lens unit 24 together with the reflective polarizing member 14. In this display system, the polarizing member 10 is the reflective polarizing member 14. In the lens unit 4, the second linearly polarized light emitted from the second phase difference member 23b toward the reflective polarizing member 14 is reflected by the reflective polarizing member 14, and is incident on the second phase difference member 23b from the first principal surface 20a side, where it is converted into the second circularly polarized light. The second circularly polarized light emitted from the second principal surface 20b side of the second phase difference member 23b can maintain high ellipticity even after passing through the protective member 30. As a result, polarization disturbance in the display system can be suppressed, and visibility can be improved.

[0108] In one embodiment, the optical laminate obtained by the manufacturing method described in Section A can be applied to the display system 2 as an optical laminate including a second phase difference member 23b. The optical laminate used in this embodiment includes a phase difference member 20 of configuration 1 that converts linearly polarized light into circularly polarized light using one λ / 4 layer. The optical laminate is disposed in front of the half mirror 18 so that the first main surface 20a of the phase difference member 20 faces the half mirror 18, thereby allowing the phase difference member 20 to function as the second phase difference member 23b. For example, as shown in FIG. 12 , a display system in which the second phase difference member 23b is integrated with the first lens unit 16 can be constructed by bonding the optical laminate 100A to the first lens unit 16 with a pressure-sensitive adhesive layer 40 (in the illustrated example, the reflective polarizing member 14 is integrated with the second lens unit 24). In the lens unit 4, the first circularly polarized light emitted from the first phase difference member 23a enters the second phase difference member 23b from the first main surface side 20a and is converted into the second linearly polarized light. The second linearly polarized light emitted from the second main surface 20b of the second phase difference member 23b can maintain its polarization state even after passing through the protective member 30 (in other words, changes in ellipticity can be suppressed). Furthermore, the circularly polarized light reflected by the half mirror enters the second phase difference member 23b from the first main surface side 20a and is converted into third linearly polarized light. The third linearly polarized light emitted from the second main surface 20b of the second phase difference member 23b can maintain its polarization state even after passing through the protective member 30. As a result, polarization disturbance in the display system can be suppressed, and visibility can be improved.

[0109] The present invention will be specifically described below using examples, but the present invention is not limited to these examples. The test and evaluation methods used in the examples are as follows. The term "parts" means "parts by weight" unless otherwise specified, and the term "%" means "% by weight" unless otherwise specified.

[0110] (1) Thickness Thicknesses of 10 μm or less were measured using a scanning electron microscope (manufactured by JEOL Ltd., product name "JSM-7100F"). Thicknesses exceeding 10 μm were measured using a digital micrometer (manufactured by Anritsu Corporation, product name "KC-351C"). (2) Retardation Value Retardation values ​​at a predetermined wavelength were measured at 23°C using a retardation / ellipsoidal polarization measuring device (manufactured by Oji Scientific Instruments, product names "KOBRA-HBR" and "KOBRA-HBPR"). (3) Single Transmittance and Degree of Polarization of Polarizing Element The single transmittance Ts, parallel transmittance Tp, and crossed transmittance Tc of the polarizing element were measured using a spectrophotometer (manufactured by Otsuka Electronics Co., Ltd., "LPF-200"). These Ts, Tp, and Tc are Y values ​​measured using a 2-degree visual field (C light source) according to JIS Z8701 and corrected for luminosity. The degree of polarization of the polarizing member was calculated from the obtained Tp and Tc using the following formula: Degree of polarization (%)={(Tp−Tc) / (Tp+Tc)} １／２ ×100 (4) Axial Angle The axial angle was measured using a Mueller matrix polarimeter (manufactured by AXOMETRICS, product name "AxoScan") at a measurement wavelength of 450 nm, 550 nm, or 650 nm.

[0111] [Production Example 1: Preparation of Absorptive Polarizing Member A] (Preparation of Absorptive Polarizing Film) A long, amorphous, isophthalic acid-copolymerized polyethylene terephthalate film (thickness: 100 μm) with a Tg of approximately 75°C was used as a thermoplastic resin substrate, and one side of the resin substrate was subjected to a corona treatment. A PVA-based resin (a 9:1 mixture of polyvinyl alcohol (degree of polymerization: 4200, degree of saponification: 99.2 mol%) and acetoacetyl-modified PVA (manufactured by Mitsubishi Chemical Corporation, trade name "GOHSENEX Z410") was prepared by mixing 100 parts by weight of the resin with 13 parts by weight of potassium iodide, and the resulting solution was dissolved in water to prepare an aqueous PVA solution (coating solution). The PVA aqueous solution was applied to the corona-treated surface of the resin substrate and dried at 60°C to form a 13 μm-thick PVA-based resin layer, producing a laminate. The resulting laminate was uniaxially stretched 2.4 times in the longitudinal direction (machine direction) in an oven at 130°C (auxiliary in-air stretching treatment). The laminate was then immersed in an insolubilizing bath (a boric acid aqueous solution obtained by blending 4 parts by weight of boric acid with 100 parts by weight of water) at a liquid temperature of 40°C for 30 seconds (insolubilization treatment). The laminate was then immersed in a dyeing bath (an iodine aqueous solution obtained by blending iodine and potassium iodide in a weight ratio of 1:7 with 100 parts by weight of water) at a liquid temperature of 30°C for 60 seconds while adjusting the concentration so that the single-unit transmittance (Ts) of the resulting absorptive polarizing film would have a desired value (dyeing treatment). The laminate was then immersed in a crosslinking bath (a boric acid aqueous solution obtained by blending 3 parts by weight of potassium iodide and 5 parts by weight of boric acid with 100 parts by weight of water) at a liquid temperature of 40°C for 30 seconds (crosslinking treatment). The laminate was then immersed in a boric acid aqueous solution (boric acid concentration: 4 wt %, potassium iodide concentration: 5 wt %) at a liquid temperature of 70°C and uniaxially stretched in the longitudinal direction (machine direction) between rolls operating at different peripheral speeds to a total stretch ratio of 5.5 (underwater stretching treatment). The laminate was then immersed in a cleaning bath (aqueous solution obtained by blending 4 parts by weight of potassium iodide with 100 parts by weight of water) at a liquid temperature of 20°C (washing treatment). The laminate was then dried in an oven maintained at approximately 90°C and brought into contact with a stainless steel heated roll maintained at a surface temperature of approximately 75°C (drying shrinkage treatment). The shrinkage rate of the laminate in the width direction due to the drying shrinkage treatment was 5.2%. In this manner, an absorptive polarizing film having a thickness of approximately 5 μm was formed on the resin substrate.

[0112] (Preparation of Absorptive Polarizing Member) A 20 μm-thick acrylic film having a lactone ring structure was bonded as a protective layer to the surface of the obtained absorptive polarizing film (the surface opposite to the resin substrate) via a UV-curable adhesive. Specifically, the curable adhesive was applied to a thickness of 2 μm, and the films were bonded using a rolling mill. The adhesive was then cured by irradiating it with UV light from the acrylic film side. The resin substrate was then peeled off. In this way, a roll-shaped absorptive polarizing member A having a configuration of [acrylic film / absorptive polarizing film] was obtained. The single transmittance (Ts) of the absorptive polarizing member A was 43.4%, and the polarization degree was 99.993%.

[0113] [Production Example 2A: Preparation of λ / 4 Layer A] A batch polymerization apparatus consisting of two vertical reactors equipped with stirring blades and reflux condensers controlled to 100°C was charged with 29.60 parts by weight (0.046 mol) of bis[9-(2-phenoxycarbonylethyl)fluoren-9-yl]methane, 29.21 parts by weight (0.200 mol) of isosorbide (ISB), 42.28 parts by weight (0.139 mol) of spiroglycol (SPG), 63.77 parts by weight (0.298 mol) of diphenyl carbonate (DPC), and 1.19 × 10 mol of calcium acetate monohydrate as a catalyst. －２ Part by weight (6.78 x 10 －５mol) was charged. After purging the reactor with nitrogen under reduced pressure, heating was performed with a heat medium, and stirring was initiated when the internal temperature reached 100°C. 40 minutes after the start of the temperature increase, the internal temperature reached 220°C, and while controlling to maintain this temperature, pressure reduction was initiated. 90 minutes after reaching 220°C, the pressure was reduced to 13.3 kPa. Phenol vapor by-produced during the polymerization reaction was introduced into a reflux condenser at 100°C, and a small amount of monomer components contained in the phenol vapor were returned to the reactor, while uncondensed phenol vapor was introduced into a condenser at 45°C and recovered. Nitrogen was introduced into the first reactor, and the pressure was temporarily restored to atmospheric pressure. The oligomerized reaction liquid in the first reactor was then transferred to the second reactor. Next, heating and pressure reduction in the second reactor were initiated, and the internal temperature reached 240°C and the pressure reached 0.2 kPa in 50 minutes. Polymerization was then allowed to proceed until the predetermined stirring power was achieved. When the predetermined power was reached, nitrogen was introduced into the reactor to restore pressure, and the resulting polyester carbonate resin was extruded into water and cut into strands to obtain pellets. The resulting polyester carbonate resin (pellets) was vacuum-dried at 80 ° C for 5 hours, and then a film-forming device equipped with a single-screw extruder (manufactured by Toshiba Machine Co., Ltd., cylinder setting temperature: 250 ° C), a T-die (width 200 mm, setting temperature: 250 ° C), a chill roll (setting temperature: 120-130 ° C), and a winder was used to produce a long resin film with a thickness of 130 μm. The obtained long resin film was stretched in the width direction at a stretching temperature of 140 ° C and a stretch ratio of 2.7 times, and wound into a roll. This produced a roll-shaped λ / 4 layer A with a thickness of 47 μm and a slow axis in the width direction. The λ / 4 layer A had an Re(450) of 119 nm, an Re(550) of 139 nm, and an Re(650) of 147 nm, and exhibited reverse dispersion wavelength characteristics. The Nz coefficient(590) of the λ / 4 layer A was 1.2.

[0114] [Production Example 2B: Preparation of λ / 4 Layer B] A long norbornene-based resin film (manufactured by Zeon Corporation, trade name "Zeonor", thickness 40 μm) was stretched longitudinally at the free end by adjusting the stretching ratio and stretching temperature so that the in-plane retardation Re(590) was 135 nm. A long λ / 4 layer B having a thickness of 34 μm and a slow axis in the longitudinal direction was produced. The λ / 4 layer B had a refractive index characteristic of nx > ny = nz. The Re(450) / Re(550) of the λ / 4 layer B was 1.004, indicating approximately flat dispersion wavelength characteristics. The surface smoothness of the λ / 4 layer B was 0.32 arcmin.

[0115] [Production Example 2C: Preparation of λ / 2 Layer A] A long norbornene-based resin film (manufactured by Zeon Corporation, trade name "Zeonor", thickness 50 μm) was stretched longitudinally at the free end by adjusting the stretching ratio and stretching temperature so that the in-plane retardation Re(590) was 280 nm. A long λ / 2 layer A having a thickness of 32 μm and a slow axis in the longitudinal direction was prepared by free end longitudinal stretching. The λ / 2 layer A had a refractive index characteristic of nx > ny = nz. The Re(450) / Re(550) of the λ / 2 layer A was 1.004, showing approximately flat dispersion wavelength characteristics. The surface smoothness of the λ / 2 layer A was 0.42 arcmin.

[0116] [Production Example 3A: Fabrication of Protective Member A] (Preparation of Hard Coat Layer-Forming Material) 50 parts of a urethane acrylic oligomer (manufactured by Shin-Nakamura Chemical Co., Ltd., "NK Oligo UA-53H"), 30 parts of a polyfunctional acrylate containing pentaerythritol triacrylate as a main component (manufactured by Osaka Organic Chemical Industry Ltd., trade name "Viscoat #300"), 20 parts of 4-hydroxybutyl acrylate (manufactured by Osaka Organic Chemical Industry Ltd.), 1 part of a leveling agent (manufactured by DIC Corporation, "GRANDICPC4100"), and 3 parts of a photopolymerization initiator (manufactured by Ciba Japan KK, "Irgacure 907") were mixed and diluted with methyl isobutyl ketone to a solids concentration of 50%, to prepare a hard coat layer-forming material.

[0117] (Preparation of Coating Liquid for Forming High Refractive Index Layer) 100 parts by weight of a polyfunctional acrylate (manufactured by Arakawa Chemical Industries, Ltd., trade name "Opstar KZ6728", solid content 20 wt%), 3 parts by weight of a leveling agent (manufactured by DIC Corporation, "GRANDICPC4100"), and 3 parts by weight of a photopolymerization initiator (manufactured by BASF Corporation, trade name "OMNIRAD907", solid content 100 wt%) were mixed. The mixture was diluted with butyl acetate as a dilution solvent to a solid content of 12 wt%, and the mixture was stirred to prepare a coating liquid for forming a high refractive index layer.

[0118] (Preparation of Coating Solution A for Forming Low Refractive Index Layer) 100 parts by weight of a polyfunctional acrylate containing pentaerythritol triacrylate as a main component (manufactured by Osaka Organic Chemical Industry Ltd., trade name "Viscoat #300", solid content 100 wt%), 150 parts by weight of hollow nanosilica particles (manufactured by JGC Catalysts and Chemicals Industries, Ltd., trade name "Surulia 5320", solid content 20 wt%, weight average particle diameter 75 nm), 50 parts by weight of solid nanosilica particles (manufactured by Nissan Chemical Industries, Ltd., trade name "MEK-2140Z-AC", solid content 30 wt%, weight average particle diameter 10 nm), 12 parts by weight of a fluorine-containing additive (manufactured by Shin-Etsu Chemical Co., Ltd., trade name "KY-1203", solid content 20 wt%), and 3 parts by weight of a photopolymerization initiator (manufactured by BASF, trade name "OMNIRAD907", solid content 100 wt%) were mixed. To the mixture was added a mixed solvent of TBA (tertiary butyl alcohol), MIBK (methyl isobutyl ketone), and PMA (propylene glycol monomethyl ether acetate) in a weight ratio of 60:25:15 as a dilution solvent, so that the total solid content was 4 wt %, and the mixture was stirred to prepare a coating liquid for forming a low refractive index layer.

[0119] The above hard coat layer-forming material was applied to an acrylic film (thickness: 40 μm) having a lactone ring structure, and heated at 90° C. for 1 minute. After heating, the applied layer was irradiated with a high-pressure mercury lamp at an integrated light intensity of 300 mJ / cm 2 ２The coating layer was cured by irradiating ultraviolet light of 1000 W / cm 2 to produce an acrylic film (thickness: 44 μm, surface smoothness of the hard coat layer side: 0.4 arcmin) on which a 4 μm-thick hard coat layer was formed. Next, the coating liquid for forming a high refractive index layer was applied onto the hard coat layer using a wire bar, and the applied coating liquid was heated at 80° C. for 1 minute and dried to form a coating film. The dried coating film was irradiated with ultraviolet light of 300 mJ / cm 2 using a high-pressure mercury lamp. ２ The coating film was cured by irradiating it with ultraviolet light of 1000 kJ / cm to form a high refractive index layer having a thickness of 140 nm. Subsequently, the coating liquid for forming the low refractive index layer was applied onto the high refractive index layer using a wire bar, and the applied coating liquid was heated at 80°C for 1 minute and dried to form a coating film. The dried coating film was irradiated with ultraviolet light of 300 mJ / cm to form a high refractive index layer having a thickness of 140 nm. ２ The coating film was cured by irradiating it with ultraviolet light of 100 . ...

[0120] [Production Example 3B: Preparation of Protective Member B] The same hard coat layer-forming material as in Production Example 3A was applied to a triacetyl cellulose film (manufactured by Fujifilm Corporation, trade name "TG60UL", thickness 60 μm) and heated at 90° C. for 1 minute. After heating, the applied layer was irradiated with a high-pressure mercury lamp at an integrated light intensity of 300 mJ / cm ２The coating layer was cured by irradiating ultraviolet rays of 1000 W / cm 2 to prepare a triacetyl cellulose film (thickness: 72 μm) on which a hard coat layer of 12 μm in thickness was formed. Next, the same high refractive index layer-forming coating liquid as in Production Example 3A was applied onto the hard coat layer using a wire bar, and the applied coating liquid was heated at 80° C. for 1 minute and dried to form a coating film. The dried coating film was irradiated with ultraviolet rays of 300 mJ / cm 2 to prepare a triacetyl cellulose film (thickness: 72 μm). ２ The coating film was cured by irradiating it with ultraviolet light of 1000 kJ / cm to form a high refractive index layer having a thickness of 140 nm. Subsequently, the same low refractive index layer-forming coating liquid as in Production Example 3A was applied onto the high refractive index layer using a wire bar, and the applied coating liquid was heated at 80°C for 1 minute and dried to form a coating film. The dried coating film was irradiated with ultraviolet light of 1000 kJ / cm to form a high refractive index layer having a thickness of 140 nm. ２ The coating was cured by irradiating ultraviolet light of 100 . ...

[0121] Examples 1-1 to 1-3, Comparative Examples 1-1 to 1-3, Reference Example 1 The absorptive polarizing member A, λ / 4 layer A, and pressure-sensitive adhesive layer-attached protective member A prepared in the above production examples were punched into rectangular shapes so that the optical axis formed a predetermined angle with respect to the side direction, and then laminated sheet to sheet to produce an optical laminate having the configuration and axis angle shown in Table 1. Specifically, the release liner was peeled and removed from the pressure-sensitive adhesive layer-attached protective member A, and the exposed pressure-sensitive adhesive layer was used to bond the λ / 4 layer A to the absorptive polarizing member A. Next, an absorptive polarizing member A was attached to the λ / 4 layer side of the resulting laminate via an acrylic pressure-sensitive adhesive (thickness 15 μm). The absorptive polarizing member A was laminated so that the surface of the absorptive polarizing film side of the absorptive polarizing member A faced the λ / 4 layer A. An optical laminate not including the protective member A was also prepared as Reference Example 1.

[0122]

[0123] Examples 2-1 to 2-3, Comparative Examples 2-1 to 2-3 The absorptive polarizing member A, λ / 4 layer A, and pressure-sensitive adhesive layer-attached protective member B produced in the above production examples were punched into rectangular shapes so that the optical axis formed a predetermined angle with respect to the side direction, and optical laminates were produced by laminating them so as to have the configuration and axis angle shown in Table 2. The optical laminates were produced sheet to sheet in the same manner as in Example 1-1, etc.

[0124]

[0125] For the optical laminates obtained in Examples 1-1 to 2-3, Comparative Examples 1-1 to 2-3, and Reference Example 1, the ellipticity of the light emitted from the opposite surface (polar angle 0°) at wavelengths of 450 nm, 550 nm, and 650 nm was measured using a Mueller matrix polarimeter (manufactured by AXOMETRICS, product name "AxoScan"), with light incident from the front direction. The difference between the ellipticity measured for each optical laminate and the ellipticity measured for the optical laminate of Reference Example 1 (ellipticity in Reference Example 1 - ellipticity in the Examples or Comparative Examples) is shown in Figures 13 and 14. The ellipticities of the emitted light at wavelengths of 450 nm, 550 nm, and 650 nm measured for the optical laminate of Reference Example 1 were 0.908, 0.983, and 0.860, respectively.

[0126] As shown in Figure 13, in the optical laminates of Comparative Examples 1-1 to 1-3, the change in ellipticity of transmitted light (emitted light) (difference in ellipticity) compared to the optical laminate of Reference Example 1 exceeds 0.02 depending on the wavelength, but in the optical laminates of Examples 1-1 to 1-3, the change is kept to 0.02 or less at all wavelengths. Also, as shown in Figure 14, in the optical laminates of Comparative Examples 2-1 to 2-3, the change in ellipticity of transmitted light compared to the optical laminate of Reference Example 1 exceeds 0.01 depending on the wavelength, but in the optical laminates of Examples 2-1 to 2-3, the change is kept to 0.01 or less at all wavelengths. As described above, in the optical laminates of the Examples, the change in ellipticity of transmitted light compared to the Reference Example is more suppressed than in the optical laminate of the Comparative Example.

[0127] Examples 3-1 to 3-3, Comparative Examples 3-1 to 3-3, Reference Example 2 The absorptive polarizing element A, λ / 2 layer A, λ / 4 layer B, and pressure-sensitive adhesive layer-attached protective element A prepared in the above manufacturing examples were punched into rectangular shapes so that the optical axis formed a predetermined angle relative to the side direction, and then laminated sheet to sheet to produce an optical laminate having the configuration and axis angle shown in Table 3. Specifically, the λ / 2 layer A and the λ / 4 layer B were bonded together via an acrylic pressure-sensitive adhesive layer (5 μm thick) to prepare laminate A. Next, the release liner was peeled and removed from the pressure-sensitive adhesive layer-attached protective element A, and the protective element A was bonded to the λ / 4 layer B side of laminate A via the exposed pressure-sensitive adhesive layer. Next, the absorptive polarizing element A was bonded to the λ / 2 layer A side of laminate A via an acrylic pressure-sensitive adhesive (15 μm thick). The absorptive polarizing element A was laminated so that the surface of the absorptive polarizing film side of the absorptive polarizing element A faced the λ / 2 layer A. In addition, an optical laminate not including the protective member A was produced as Reference Example 2.

[0128]

[0129] [Examples 4-1 to 4-3, Comparative Examples 4-1 to 4-3] Optical laminates having the configurations and axial angles shown in Table 4 were produced in the same manner as in Examples 3-1 to 3-3 and Comparative Examples 3-1 to 3-3, except that the pressure-sensitive adhesive layer-attached protective member B was used instead of the pressure-sensitive adhesive layer-attached protective member A.

[0130]

[0131] For the optical laminates obtained in Examples 3-1 to 4-3, Comparative Examples 3-1 to 4-3, and Reference Example 2, the ellipticity of the light emitted from the opposite surface (polar angle 0°) at wavelengths of 450 nm, 550 nm, and 650 nm was measured using a Mueller matrix polarimeter (manufactured by AXOMETRICS, product name "AxoScan"), with light incident from the front direction. The difference between the ellipticity measured for each optical laminate and the ellipticity measured for the optical laminate of Reference Example 2 (ellipticity in Reference Example 2 - ellipticity in the Examples or Comparative Examples) is shown in Figures 15 and 16. The ellipticities of the emitted light at wavelengths of 450 nm, 550 nm, and 650 nm measured for the optical laminate of Reference Example 2 were 0.873, 0.944, and 0.934, respectively.

[0132] As shown in Figure 15, in the optical laminates of Comparative Examples 3-1 to 3-3, the change in ellipticity of transmitted light (emitted light) compared to the optical laminate of Reference Example 2 exceeds 0.02 at some wavelengths, but in the optical laminates of Examples 3-1 to 3-3, the change is kept to 0.02 or less at all wavelengths. Also, as shown in Figure 16, in the optical laminates of Comparative Examples 4-1 to 4-3, the change in ellipticity of transmitted light compared to the optical laminate of Reference Example 2 exceeds 0.01 at some wavelengths, but in the optical laminates of Examples 4-1 to 4-3, the change is kept to 0.01 or less at all wavelengths. As described above, in the optical laminates of the Examples, the change in ellipticity of transmitted light compared to Reference Example is more suppressed than in the optical laminates of the Comparative Examples.

[0133] The present invention is not limited to the above-described embodiment, and various modifications are possible. For example, the configurations shown in the above-described embodiment can be replaced with configurations that are substantially the same as those shown in the above-described embodiment, that have the same effects, or that can achieve the same purpose.

[0134] A display system according to an embodiment of the present invention can be used in a display such as VR goggles, for example.

[0135] 2 Display system, 4 Lens portion, 10 Polarizing member, 12 Display element, 12a Display surface, 14 Reflective polarizing member, 16 First lens portion, 18 Half mirror, 20 Phase difference member, 21 λ / 4 layer, 22 λ / 2 layer, 23a First phase difference member, 23b Second phase difference member, 24 Second lens portion, 30 Protective member, 40 Pressure-sensitive adhesive layer, 100 Optical laminate.

Claims

1. A method for manufacturing an optical laminate, comprising: a phase difference element having a first principal surface and a second principal surface opposed to each other, which converts linearly polarized light incident on the first principal surface side into circularly polarized light and emits the circularly polarized light from the second principal surface side; and a protective member having a slow axis and arranged on the second principal surface side of the phase difference element, the method comprising laminating the phase difference element and the protective member so that the angle between the polarization direction of the linearly polarized light and the slow axis of the protective member is 15° or less or 75° to 105°.

2. The manufacturing method according to claim 1, wherein the retardation member includes a λ / 4 layer having an Re(550) of 100 nm to 190 nm, and laminating the retardation member and the protective member includes laminating the λ / 4 layer and the protective member so that the angle between the slow axis of the λ / 4 layer and the slow axis of the protective member is 30° to 60°.

3. The manufacturing method according to claim 2, wherein laminating the retardation member and the protective member includes laminating the λ / 4 layer and the protective member, both of which are in the form of sheets.

4. The manufacturing method according to claim 3, further comprising: punching out the long λ / 4 layer so that its slow axis is approximately perpendicular or parallel to the side direction to obtain the rectangular λ / 4 layer; and punching out the long protective member so that its slow axis forms an angle of 30° to 60° with the side direction to obtain the rectangular protective member.

5. The manufacturing method according to claim 3, further comprising: punching out the elongated λ / 4 layer so that its slow axis forms an angle of 30° to 60° with the side direction to obtain the rectangular λ / 4 layer; and punching out the elongated protective member so that its slow axis is approximately perpendicular or approximately parallel to the side direction to obtain the rectangular protective member.

6. The manufacturing method according to claim 4 or 5, wherein the long λ / 4 layer has a slow axis in a direction substantially parallel to the longitudinal direction or the width direction.

7. The manufacturing method according to claim 2, wherein laminating the retardation member and the protective member includes continuously laminating the λ / 4 layer and the protective member, both of which are elongated, with their longitudinal directions aligned.

8. The manufacturing method according to claim 7, wherein the long λ / 4 layer has a slow axis in a direction of 30° to 60° with respect to the longitudinal direction.

9. The manufacturing method according to claim 1, wherein the retardation member and the protective member are laminated via an adhesive layer.

10. The manufacturing method according to claim 9, wherein the protective member having the adhesive layer provided on one surface thereof and the retardation member are laminated together.

11. The manufacturing method according to claim 1, wherein the protective member comprises a substrate, and the substrate comprises at least one resin selected from an acrylic resin and a triacetyl cellulose resin.

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