Optical laminate and integrated member

Abstract

The present invention provides: an optical laminate including a retardation layer, a resin layer, and an adhesive layer in this order, the resin layer including a thermoplastic resin; and an integrated member including a member having a curved surface part and the optical laminate integrated with the curved surface part of the member.

Description

Optical laminates and integrated components

[0001] The present invention relates to an optical laminate and an integrated member comprising the optical laminate and a member having a curved surface portion.

[0002] Image display devices, such as liquid crystal displays and electroluminescent (EL) displays (e.g., organic EL displays), are rapidly becoming widespread. In image display devices, optical components such as phase difference members and polarizing members are generally used to realize image display and improve image display performance (see, for example, Patent Document 1). These optical components can be pre-integrated and mounted on the image display device as an optical laminate.

[0003] In recent years, new applications for image display devices have been developed. For example, goggles with displays for realizing Virtual Reality (VR) (VR goggles) are beginning to be commercialized. As VR goggles are being considered for use in a variety of situations, there is a demand for lighter weight and improved visibility.

[0004] Japanese Patent Publication No. 2021-103286

[0005] The weight reduction of the VR goggles described above can be achieved, for example, by using curved lenses and adjusting the optical path by refracting light with these curved lenses. In this case, the optical components can be used integrated with the curved lenses. However, cracks may occur in the optical components (e.g., phase difference components) when they are bonded to a curved surface. Also, if the smoothness of the optical components is low, the displayed image may become blurry, affecting visibility.

[0006] In view of the above, the primary objective of the present invention is to provide an optical laminate that has high smoothness and suppresses the occurrence of cracks when integrated with a member having a curved surface.

[0007] [1] According to one aspect of the present invention, an optical laminate is provided comprising a phase difference layer, a resin layer, and an adhesive layer in that order, wherein the resin layer comprises a thermoplastic resin. [2] In the optical laminate described in [1], the resin layer may be disposed directly adjacent to the phase difference layer. [3] In the optical laminate described in [1] or [2], the indentation modulus of the resin layer may be greater than the shear modulus of the adhesive layer. [4] In the optical laminate described in any of [1] to [3], the indentation modulus of the resin layer at 25°C is 5.0 × 10 ８ [1] The pressure may be Pa or higher. [2] In the optical laminate described in any of [1] to [4] above, the ratio of the indentation modulus of the resin layer at 25°C to the shear modulus of the adhesive layer at 25°C may be 10 or more. [3] In the optical laminate described in any of [1] to [5] above, the thickness of the resin layer may be 1 μm or less. [4] In the optical laminate described in any of [1] to [6] above, the phase difference layer may be an orientation solidified layer of a liquid crystal compound. [5] In the optical laminate described in any of [1] to [7] above, the phase difference layer may be a homeotropic orientation solidified layer of a liquid crystal compound. [6] According to another aspect of the present invention, an integrated member is provided, comprising a member having a curved surface portion and an optical laminate described in any of [1] to [8] above integrated with the curved surface portion of the member. [7] In the integrated member described in [9] above, the radius of curvature of the curved surface portion may be 10 mm to 150 mm.

[0008] An optical laminate according to an embodiment of the present invention comprises a phase difference layer, a resin layer, and an adhesive layer in that order. The resin layer has excellent smoothness and can have a high modulus of elasticity, and therefore can contribute to improved smoothness and crack resistance when integrated with a member having a curved surface in the optical laminate.

[0009] This is a schematic diagram showing the general configuration of an example of a display system to which an optical laminate according to an embodiment of the present invention may be applied. This is a schematic cross-sectional view showing the general configuration of an optical laminate according to one embodiment of the present invention. This is a schematic cross-sectional view showing the general configuration of an optical laminate according to one embodiment of the present invention. This is a schematic cross-sectional view showing the general configuration of an optical laminate according to one embodiment of the present invention. Figures 5A to 5C are schematic diagrams showing an example of a method for integrating an optical laminate with a member having a curved surface. This is a diagram following Figure 5A. This is a diagram following Figure 5B. This is a schematic diagram illustrating the fixed state of the evaluation sample in a heating test.

[0010] Embodiments of the present invention will be described below with reference to the drawings, but the present invention is not limited to these embodiments. While the drawings may schematically represent the width, thickness, shape, etc., of each part compared to the embodiments in order to clarify the explanation, these are merely examples and do not limit the interpretation of the present invention. Furthermore, in the drawings, the same or equivalent elements are denoted by the same reference numerals, and redundant explanations may be omitted.

[0011] (Definitions of Terms and Symbols) The definitions of terms and symbols used herein are as follows: (1) Refractive Index (nx, ny, nz) "nx" is the refractive index in the direction in which the refractive index in the plane is maximum (i.e., in the direction of the slow phase axis), "ny" is the refractive index in the direction perpendicular to the slow phase axis in the plane (i.e., in the direction of the fast phase axis), and "nz" is the refractive index in the thickness direction. (2) In-Plane Phase Difference (Re) "Re(λ)" is the in-plane phase difference measured with light of wavelength λnm at 23°C. For example, "Re(550)" is the in-plane phase difference measured with light of wavelength 550nm at 23°C. Re(λ) can be calculated by the formula: Re(λ) = (nx - ny) × d, where d (nm) is the thickness of the layer (film). (3) Phase Difference in the Thickness Direction (Rth) "Rth(λ)" is the phase difference in the thickness direction measured with light of wavelength λnm at 23°C. For example, "Rth(550)" is the phase difference in the thickness direction measured with light of a wavelength of 550 nm at 23°C. Rth(λ) is obtained 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 obtained 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 with respect to the reference direction. Therefore, for example, "45°" means ±45°. Also in this specification, "approximately parallel" includes the range of 0° ± 10°, preferably within the range of 0° ± 5°. "Approximately orthogonal" includes the range of 90° ± 10°, preferably within the range of 90° ± 5°.

[0012] A. Display System Figure 1 is a schematic diagram showing the general configuration of an example of a display system to which an optical laminate according to an embodiment of the present invention may be applied. Figure 1 schematically illustrates the arrangement and shape of each component of the display system 2. The display system 2 comprises a display element 12, a reflective polarizing member 14, a first lens portion 16, a half mirror 18, a first phase difference member 20, a second phase difference member 22, and a second lens portion 24. The reflective polarizing member 14 is positioned in front of the display element 12 on the display surface 12a side and can reflect light emitted from the display element 12. The first lens portion 16 is positioned in the optical path between the display element 12 and the reflective polarizing member 14, and the half mirror 18 is positioned between the display element 12 and the first lens portion 16. The first phase difference member 20 is positioned in the optical path between the display element 12 and the half mirror 18, and the second phase difference member 22 is positioned in the optical path between the half mirror 18 and the reflective polarizing member 14.

[0013] The components positioned in front of the half-mirror or first lens section (in the illustrated example, the half-mirror 18, first lens section 16, second phase difference member 22, reflective polarizing member 14, and second lens section 24) may be collectively referred to as the lens section (lens section 4).

[0014] The display element 12 is, for example, a liquid crystal display or an organic EL display, and has a display surface 12a for displaying an image. The light emitted from the display surface 12a passes through a polarizing member (typically a polarizing film) that may be included in the display element 12, and is emitted as first linearly polarized light.

[0015] The first phase difference member 20 includes a first λ / 4 member capable of converting a first linearly polarized light incident on the first phase difference member 20 into a first circularly polarized light. If the first phase difference member does not include any members other than the first λ / 4 member, the first phase difference member may correspond to the first λ / 4 member. The first phase difference member 20 may be provided integrally with the display element 12.

[0016] The half mirror 18 transmits light emitted from the display element 12 and reflects the light reflected by the reflective polarizing member 14 back towards the reflective polarizing member 14. The half mirror 18 is integrally provided with the first lens portion 16.

[0017] The second phase difference member 22 includes a second λ / 4 member that can transmit light reflected by the reflective polarizing member 14 and the half mirror 18 through the reflective polarizing member 14. If the second phase difference member does not include any members other than the second λ / 4 member, the second phase difference member may correspond to the second λ / 4 member. The second phase difference member 22 may be provided integrally with the first lens portion 16.

[0018] The first circularly polarized light emitted from the first λ / 4 member included in the first phase difference member 20 passes through the half mirror 18 and the first lens portion 16 and is converted into a second linearly polarized light by the second λ / 4 member included in the second phase difference member 22. The second linearly polarized light emitted from the second λ / 4 member is reflected towards 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 in the same direction as the reflection axis of the reflective polarizing member 14. Therefore, the second linearly polarized light incident on the reflective polarizing member 14 is reflected by the reflective polarizing member 14.

[0019] The second linearly polarized light reflected by the reflective polarizing member 14 is converted into a second circularly polarized light by the second λ / 4 member included in the second phase difference member 22. The second circularly polarized light emitted from the second λ / 4 member passes through the first lens portion 16 and is reflected by the half mirror 18. The second circularly polarized light reflected by the half mirror 18 passes through the first lens portion 16 and is converted into a third linearly polarized light by the second λ / 4 member included in the second phase difference member 22. The third linearly polarized light is transmitted through the reflective polarizing member 14. At this time, the polarization direction of the third linearly polarized light incident on the reflective polarizing member 14 is in the same direction as the transmission axis of the reflective polarizing member 14. Therefore, the third linearly polarized light incident on the reflective polarizing member 14 is transmitted through the reflective polarizing member 14.

[0020] Light that has passed through the reflective polarizing member 14 passes through the second lens portion 24 and enters the user's eye 26.

[0021] For example, the absorption axis of a polarizing member that may be included in the display element 12 and the reflection axis of a reflective polarizing member 14 may be arranged substantially parallel to each other or substantially orthogonal to each other. The angle between the absorption axis of a polarizing member that may be included in the display element 12 and the lagging axis of a first λ / 4 member included in the first phase difference member 20 is, for example, 40° to 50°, may be 42° to 48°, or may be about 45°. The angle between the absorption axis of a polarizing member that may be included in the display element 12 and the lagging axis of a second λ / 4 member included in the second phase difference member 22 is, for example, 40° to 50°, may be 42° to 48°, or may be about 45°.

[0022] The in-plane phase difference Re(550) of the first λ / 4 member is, for example, 100 nm to 190 nm, but may also be 110 nm to 180 nm, 130 nm to 160 nm, or 135 nm to 155 nm. For example, it is preferable that the first λ / 4 member exhibits an inverse dispersion wavelength characteristic in which the phase difference value increases with the wavelength of the measured light. In this case, the Re(450) / Re(550) of the first λ / 4 member is, for example, 0.75 or more and less than 1, and may also be 0.8 or more and 0.95 or less.

[0023] The in-plane phase difference Re(550) of the second λ / 4 member is, for example, 100 nm to 190 nm, but may also be 110 nm to 180 nm, 130 nm to 160 nm, or 135 nm to 155 nm. For example, it is preferable that the second λ / 4 member exhibits an inverse dispersion wavelength characteristic in which the phase difference value increases with the wavelength of the measured light. In this case, the Re(450) / Re(550) of the second λ / 4 member is, for example, 0.75 or more and less than 1, and may also be 0.8 or more and 0.95 or less.

[0024] Although not shown in the diagram, an absorptive polarizing member may be positioned in front of the reflective polarizing member 14. The absorptive polarizing member may be positioned between the reflective polarizing member 14 and the second lens portion 24. The reflection axis of the reflective polarizing member and the absorption axis of the absorptive polarizing member may be positioned substantially parallel to each other, and the transmission axis of the reflective polarizing member and the transmission axis of the absorptive polarizing member may be positioned substantially parallel to each other.

[0025] In the lens portion 4, a space may be formed between the first lens portion 16 and the second lens portion 24. In this case, it is preferable that the member disposed between the first lens portion 16 and the second lens portion 24 is integrally provided with either the first lens portion 16 or the second lens portion 24. For example, it is preferable that the member disposed between the first lens portion 16 and the second lens portion 24 is integrated with either the first lens portion 16 or the second lens portion 24 via an adhesive layer. With such a configuration, for example, the handling of each member can be improved.

[0026] In the display system 2 shown in Figure 1, both the first lens portion 16 and the second lens portion 24 have curved surfaces. When a member placed between the first lens portion 16 and the second lens portion 24 is integrated with the first lens portion 16 and / or the second lens portion 24, which have curved surfaces, these members are usually bonded together so as to conform to the surface shape of the curved surface, in a state where their shape is easily deformed by heating. Therefore, an optical laminate that includes a member placed between the first lens portion 16 and the second lens portion 24, and in which the occurrence of cracks in the member due to heating during curved surface bonding is suppressed, is useful for manufacturing display systems using curved lenses. Note that, unlike the illustrated example, in the display system 2, only one of the first lens portion 16 and the second lens portion 24 may have a curved surface.

[0027] B. Optical Laminate The optical laminate according to an embodiment of the present invention includes, in this order, a phase difference layer (sometimes referred to as the first phase difference layer), a resin layer, and an adhesive layer (sometimes referred to as the first adhesive layer), wherein the resin layer contains a thermoplastic resin. The resin layer containing the thermoplastic resin and the adhesive layer may have higher smoothness than a resin layer containing a curing resin that undergoes curing shrinkage during molding. Furthermore, the resin layer containing the thermoplastic resin has a higher elastic modulus than the adhesive layer and can function as a protective layer for the phase difference layer. Therefore, the optical laminate having the above configuration has excellent smoothness and can suppress the occurrence of cracks in the phase difference layer when integrated with a member having a curved surface.

[0028] In the above optical laminate, the resin layer is typically disposed directly adjacent to the retardation layer. In other words, there is no layer intervening between the resin layer and the retardation layer, and these layers are laminated in close contact with each other. Also, in the above optical laminate, the resin layer is typically disposed directly adjacent to the adhesive layer. In other words, there is no layer intervening between the resin layer and the adhesive layer, and these layers are laminated in close contact with each other.

[0029] The above optical laminate may include an adhesive layer as the outermost layer. An optical laminate including an adhesive layer as the outermost layer can be bonded to an adjacent member through the adhesive layer of the outermost layer and integrated. The first adhesive layer may be the adhesive layer of the outermost layer, or an adhesive layer different from the first adhesive layer (which may be referred to as the second adhesive layer) may be the adhesive layer of the outermost layer.

[0030] The above optical laminate may further include any appropriate member as needed. Examples of members that the optical laminate may further include are another retardation layer (which may be referred to as the second retardation layer), a reflective polarizing member, an absorptive polarizing member, a protective member, and the like.

[0031] The overall thickness of the above optical laminate is, for example, 20 μm to 300 μm, preferably 100 μm to 220 μm. The smoothness of the above optical laminate is, for example, 0.25 arcmin or less, preferably 0.20 arcmin or less.

[0032] FIG. 2 is a schematic cross-sectional view showing a schematic configuration of an optical laminate according to one embodiment of the present invention. The optical laminate 100A includes a first retardation layer 22a, a resin layer 30, and a first adhesive layer 41 in this order. The first retardation layer 22a and the resin layer 30 are directly adjacent to each other, and the resin layer 30 and the first adhesive layer 41 are directly adjacent to each other. In the optical laminate 100A, a second adhesive layer 42 as the outermost layer is disposed on the side opposite to the side where the resin layer 30 of the first retardation layer 22a is disposed. Also, in the optical laminate 100A, a second retardation layer 22b is disposed on the side opposite to the side where the resin layer 30 of the first adhesive layer 41 is disposed.

[0033] FIG. 3 is a schematic cross-sectional view showing a schematic configuration of an optical laminate according to one embodiment of the present invention. The optical laminate 100B includes a first retardation layer 22a, a resin layer 30, and a first adhesive layer 41 in this order. The first retardation layer 22a and the resin layer 30 are directly adjacent to each other, and the resin layer 30 and the first adhesive layer 41 are directly adjacent to each other. In the optical laminate 100B, a second retardation layer 22b and a second adhesive layer 42 are arranged in this order on the side opposite to the side where the resin layer 30 of the first adhesive layer 41 is arranged.

[0034] FIG. 4 is a schematic cross-sectional view showing a schematic configuration of an optical laminate according to one embodiment of the present invention. The optical laminate 100C includes a first retardation layer 22a, a resin layer 30, and a first adhesive layer 41 in this order. The first retardation layer 22a and the resin layer 30 are directly adjacent to each other, and the resin layer 30 and the first adhesive layer 41 are directly adjacent to each other. In the optical laminate 100C, a second adhesive layer 42 as an outermost layer is arranged on the side opposite to the side where the resin layer 30 of the first retardation layer 22a is arranged. Further, in the optical laminate 100C, a second retardation layer 22b, a reflective polarizing member 14, an absorptive polarizing member 15, and a protective member 50 are arranged in this order on the side opposite to the side where the resin layer 30 of the first adhesive layer 41 is arranged. The reflective polarizing member 14, the absorptive polarizing member 15, and the protective member 50 are laminated via adhesive layers 62, 63, and 64, respectively.

[0035] Preferably, either one of the first retardation layer 22a and the second retardation layer 22b is a member that can function as a second λ / 4 member, and the other is a member (so-called positive C-plate) that can show a refractive index characteristic of nz>nx = ny. Such a first retardation layer 22a and a second retardation layer 22b can constitute a second retardation member 22 including the second λ / 4 member in the display system 2 described in item A. The second retardation member 22 including the first retardation layer 22a and the second retardation layer 22b can be integrated with the first lens unit 16 via, for example, the second adhesive layer 42. By including a positive C-plate in addition to the second λ / 4 member in the second retardation member 22, light leakage (for example, light leakage in an oblique direction) in the display system 2 can be suppressed.

[0036] In one embodiment, the phase difference layer closer to the second adhesive layer 42 (the first phase difference layer 22a in optical laminates 100A and 100C and the second phase difference layer 22b in optical laminate 100B) is a positive C plate, and the other phase difference layer is a second λ / 4 member. By bonding an optical laminate with such a configuration to the front side of the first lens portion via the second adhesive layer, a display system can be obtained in which the second λ / 4 member is positioned in front of the positive C plate.

[0037] The first phase difference layer 22a can be formed from any suitable material depending on the desired optical properties. The first phase difference layer is, for example, an oriented solidified layer of a liquid crystal compound (hereinafter also referred to as a liquid crystal oriented solidified layer) or a stretched film of a resin film, and is preferably a liquid crystal oriented solidified layer. A liquid crystal oriented solidified layer (for example, a homeotropic oriented solidified layer) may crack when heated, but the occurrence of such cracks can be suitably suppressed by directly adjacent to the resin layer.

[0038] The second phase difference layer 22b can be formed from any suitable material depending on the desired optical properties. The second phase difference layer is, for example, a liquid crystal alignment solidification layer or a stretched film of a resin film. When the second phase difference layer is a liquid crystal alignment solidification layer, a resin layer containing a thermoplastic resin (sometimes referred to as the second resin layer) can be placed directly adjacent to the second phase difference layer. By placing the second resin layer directly adjacent to the liquid crystal alignment solidification layer, the occurrence of cracks due to heating can be suppressed. The same explanation as for the resin layer 30 provided adjacent to the first phase difference layer can be applied to the second resin layer.

[0039] [Second λ / 4 member] The in-plane phase difference Re(550) and dispersion wavelength characteristics of the second λ / 4 member are as described in Section A.

[0040] The second λ / 4 member preferably exhibits a refractive index characteristic relating nx > ny ≥ nz. Here, "ny = nz" includes not only the case where ny and nz are exactly 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 second λ / 4 member 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.

[0041] The second λ / 4 member is formed from any suitable material that can satisfy the above characteristics. The second λ / 4 member may be, for example, a stretched resin film or a liquid crystal orientation solidified layer.

[0042] Examples of resins included in the above-mentioned 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 individually or in combination. Methods of combination include blending and copolymerization. When the first λ / 4 member exhibits inverse dispersion wavelength characteristics, a resin film containing a polycarbonate resin or a polyester carbonate resin (hereinafter sometimes simply referred to as a polycarbonate resin) can be suitably used.

[0043] Any suitable polycarbonate resin can be used as the above-mentioned polycarbonate resin. For example, the polycarbonate resin includes structural units derived from fluorene-based dihydroxy compounds, structural units derived from isosorbide-based dihydroxy compounds, and structural units derived from at least one dihydroxy compound selected from the group consisting of alicyclic diols, alicyclic dimethanol, di, tri, or polyethylene glycol, and alkylene glycol or spiroglycol. Preferably, the polycarbonate resin includes structural units derived from fluorene-based dihydroxy compounds, structural units derived from isosorbide-based dihydroxy compounds, structural units derived from alicyclic dimethanol, and / or structural units derived from di, tri, or polyethylene glycol; more preferably, it includes structural units derived from fluorene-based dihydroxy compounds, structural units derived from isosorbide-based dihydroxy compounds, and structural units derived from di, tri, or polyethylene glycol. The polycarbonate resin may optionally include structural units derived from other dihydroxy compounds. Further details regarding polycarbonate resins suitably used for the second λ / 4 member and methods for forming the second λ / 4 member are described, for example, in Japanese Patent Publication No. 2014-10291, Japanese Patent Publication No. 2014-26266, Japanese Patent Publication No. 2015-212816, Japanese Patent Publication No. 2015-212817, and Japanese Patent Publication No. 2015-212818, and the descriptions in these publications are incorporated herein by reference.

[0044] The thickness of the second λ / 4 member, which is made of a stretched resin film, is, for example, 10 μm to 100 μm, preferably 10 μm to 70 μm, and more preferably 20 μm to 60 μm.

[0045] The above-described liquid crystal orientation solidification layer is a layer in which liquid crystal compounds are oriented in a predetermined direction within the layer, and this orientation state is fixed. Note that the term "orientation solidification layer" is a concept that includes orientation hardened layers obtained by curing liquid crystal monomers, as described later. In the second λ / 4 member, typically, rod-shaped liquid crystal compounds are oriented in a state where they are aligned along the slow axis direction of the second λ / 4 member (homogenous orientation). Examples of rod-shaped liquid crystal compounds include liquid crystal polymers and liquid crystal monomers. Preferably, the liquid crystal compound is polymerizable. If the liquid crystal compound is polymerizable, the orientation state of the liquid crystal compound can be fixed by polymerizing it after orientation.

[0046] The above-mentioned liquid crystal alignment solidification layer can be formed by applying an alignment treatment to the surface of a predetermined substrate, coating the surface with a coating liquid containing a liquid crystal compound to orient 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. Specifically, these 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 deposition and photo-alignment treatment. Any appropriate treatment conditions can be adopted for each type of alignment treatment depending on the purpose.

[0047] The orientation of liquid crystal compounds is achieved by treating them at a temperature that exhibits the liquid crystal phase, depending on the type of liquid crystal compound. This temperature treatment causes the liquid crystal compound to enter a liquid crystal state, and it then orients according to the orientation treatment direction on the substrate surface.

[0048] In one embodiment, the orientation state is fixed by cooling the liquid crystal compound oriented as described above. If the liquid crystal compound is polymerizable or crosslinkable, the orientation state is fixed by subjecting the liquid crystal compound oriented as described above to a polymerization treatment or a crosslinking treatment.

[0049] As the above-mentioned liquid crystal compound, any suitable liquid crystal polymer and / or liquid crystal monomer can be used. The liquid crystal polymer and liquid crystal monomer may be used individually or in combination. Specific examples of liquid crystal compounds and methods for producing liquid crystal alignment solidified layers are described, for example, in Japanese Patent Publication No. 2006-163343, Japanese Patent Publication No. 2006-178389, and International Publication No. 2018 / 123551. The descriptions in these publications are incorporated herein by reference.

[0050] The thickness of the second λ / 4 member, which is composed of a liquid crystal alignment solidification layer, 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.

[0051] [Positive C-plate] The phase difference Rth(550) in the thickness direction 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. Here, with respect to the refractive index characteristics of the positive C-plate (nz > nx = ny), "nx = ny" includes not only the case where nx and ny are exactly equal, but also the case where nx and ny are substantially equal. The in-plane phase difference Re(550) of the positive C-plate is, for example, less than 10 nm.

[0052] The positive C plate can be formed from any suitable material. Preferably, the positive C plate consists of a film containing a liquid crystal compound fixed in a homeotropic orientation (in other words, a film containing a homeotropically oriented solidified layer). The liquid crystal compound that can be homeotropically oriented may be a liquid crystal monomer or a liquid crystal polymer. Specific examples of methods for forming such a liquid crystal compound and positive C plate include the liquid crystal compound and the method for forming the phase difference layer described in

[0020] to

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

[0053] [Resin Layer] The resin layer includes a thermoplastic resin. In one embodiment, the resin layer is a solidified or thermoset product of a coating film of an organic solvent solution of the thermoplastic resin. With such a configuration, a very thin, highly elastic resin layer can be formed directly on the phase difference layer (i.e., without an adhesive layer or tack layer). As a result, crack formation in the phase difference layer due to heating can be suppressed without compromising the weight reduction or thinning of the lens. Furthermore, the solidified or thermoset product of a coating film of an organic solvent solution of the thermoplastic resin exhibits less shrinkage when forming the resin layer compared to a cured product of a curable resin. Therefore, an optical laminate with excellent surface smoothness can be obtained.

[0054] The resin layer may further contain an isocyanate compound in addition to the thermoplastic resin. Preferably, the isocyanate compound used is tolylene diisocyanate, diphenylmethane diisocyanate, xylylene diisocyanate, or their derivatives (e.g., modified products, adducts). These may be used alone or in combination. By using such isocyanate compounds, excellent adhesion to the phase difference layer can be achieved. In addition to the above, it is preferable to use at least one of hexamethylene diisocyanate or its derivatives as the isocyanate compound.

[0055] The content of thermoplastic resin in the resin layer is, for example, 50% by weight or more, may be 55% by weight or more, or 60% by weight or more. On the other hand, the content of thermoplastic resin in the resin layer is, for example, 90% by weight or less, may be 85% by weight or less, or 80% by weight or less. The content of isocyanate compound in the resin layer is, for example, 10% by weight or more, may be 15% by weight or more, or 20% by weight or more. On the other hand, the content of isocyanate compound in the resin layer is, for example, 50% by weight or less, may be 45% by weight or less, or 40% by weight or less. The amount of hexamethylene diisocyanate and its derivatives used per 100 parts by weight of isocyanate compound is preferably 10 to 40 parts by weight.

[0056] It is preferable that the indentation elastic modulus of the resin layer is higher than the shear elastic modulus of the adjacent adhesive layer (first adhesive layer). The ratio (the former / the latter) of the indentation elastic modulus (at 25 °C) of the resin layer to the shear elastic modulus (at 25 °C) of the first adhesive layer is, for example, 10 or more, preferably 1.0×10 ２ ~1.0×10 ６ and more preferably 1.0×10 ３ ~5.0×10 ４ .

[0057] The indentation elastic modulus of the resin layer at 25 °C is, for example, 5.0×10 ８ Pa or more, preferably 5.0×10 ８ Pa to 1.0×10 １０ Pa, more preferably 8.0×10 ８ Pa to 8.0×10 ９ Pa. If the indentation elastic modulus of the resin layer is within such a range, the generation of cracks in the retardation layer can be preferably suppressed.

[0058] The thickness of the resin layer is preferably 0.01 μm to 1 μm, more preferably 0.02 μm to 0.8 μm, still more preferably 0.03 μm to 0.6 μm, and particularly preferably 0.04 μm to 0.5 μm. If the thickness of the resin layer is within such a range, the generation of cracks in the retardation layer can be preferably suppressed and high smoothness can be achieved.

[0059] The glass transition temperature (Tg) of the above thermoplastic resin is typically 85 °C or higher, preferably 90 °C or higher, more preferably 100 °C or higher, still more preferably 110 °C or higher, and particularly preferably 120 °C or higher. The upper limit of Tg can be, for example, 200 °C. If the Tg of the resin layer is within such a range, the generation of cracks in the retardation layer can be preferably suppressed.

[0060] The weight-average molecular weight (Mw) of the above thermoplastic resin is typically 50,000 or more, preferably 60,000 or more, more preferably 70,000 or more, and even more preferably 80,000 or more. The upper limit of Mw is, for example, less than 500,000, preferably 400,000 or less, and even more preferably 300,000 or less. If the weight-average molecular weight of the thermoplastic resin is within this range, the occurrence of cracks in the phase difference layer can be suitably suppressed. The weight-average molecular weight can be determined, for example, by using a gel permeation chromatograph (GPC system, manufactured by Tosoh) and converting it to polystyrene equivalent. Tetrahydrofuran can be used as the solvent.

[0061] Any suitable thermoplastic resin can be used as the thermoplastic resin contained in the resin layer. Examples of thermoplastic resins include acrylic resins and epoxy resins. Acrylic resins and epoxy resins may also be used in combination. Representative examples of acrylic resins and epoxy resins that can be used in the resin layer are described below.

[0062] ≪Acrylic Resins≫ Acrylic resins typically contain repeating units derived from (meth)acrylic acid ester monomers having a linear or branched structure as their main component. In this specification, (meth)acrylic means acrylic and / or methacrylic. Acrylic resins may contain repeating units derived from any appropriate copolymer monomer depending on the purpose. Examples of copolymer monomers include carboxyl group-containing monomers, hydroxyl group-containing monomers, amide group-containing monomers, aromatic ring-containing (meth)acrylates, and heterocyclic vinyl monomers. By appropriately setting the type, number, combination, and copolymerization ratio of monomer units, an acrylic resin having the above-mentioned predetermined Mw can be obtained.

[0063] <Boron-containing acrylic resin> In one embodiment, the acrylic resin includes a copolymer (hereinafter sometimes referred to as a boron-containing acrylic resin) obtained by polymerizing a monomer mixture containing more than 50 parts by weight of a (meth)acrylic monomer and more than 0 parts by weight but less than 50 parts by weight of a monomer represented by formula (1) (hereinafter sometimes referred to as a copolymer monomer): (In the formula, X represents a functional group comprising at least one reactive group selected from the group consisting of vinyl group, (meth)acrylic group, styryl group, (meth)acrylamide group, vinyl ether group, epoxy group, oxetane group, hydroxyl group, amino group, aldehyde group, and carboxyl group, R １ and R ２ Each of these independently represents a hydrogen atom, an optionally substituted aliphatic hydrocarbon group, an optionally substituted aryl group, or an optionally substituted heterocyclic group, R １ and R ２ (They may be connected to each other to form a ring.)

[0064] Boron-containing acrylic resins typically have repeating units represented by the following formula. By polymerizing a monomer mixture containing a copolymer monomer represented by formula (1) and a (meth)acrylic monomer, the boron-containing acrylic resin has a substituent containing boron in its side chain (for example, the repeating unit k in the following formula). This can improve adhesion to the phase difference layer when the resin layer is placed adjacent to the phase difference layer. These boron-containing substituents may be contained continuously (i.e., in blocks) or randomly in the boron-containing acrylic resin. (In the formula, R ６ (where represents any functional group, and j and k represent integers greater than or equal to 1).

[0065] <(meth)acrylic monomers> Any suitable (meth)acrylic monomer can be used as the (meth)acrylic monomer. Examples include (meth)acrylic acid ester monomers having a linear or branched structure, and (meth)acrylic acid ester monomers having a cyclic structure.

[0066] Examples of linear or branched (meth)acrylic acid ester monomers include methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, t-butyl (meth)acrylate, methyl 2-ethylhexyl (meth)acrylate, and 2-hydroxyethyl (meth)acrylate. Methyl (meth)acrylate is preferably used. Only one (meth)acrylic acid ester monomer may be used, or two or more may be used in combination.

[0067] Examples of (meth)acrylic acid ester monomers having a cyclic structure include cyclohexyl (meth)acrylate, benzyl (meth)acrylate, isobornyl (meth)acrylate, 1-adamantyl (meth)acrylate, dicyclopentenyl (meth)acrylate, dicyclopentenyloxyethyl (meth)acrylate, dicyclopentanyl (meth)acrylate, biphenyl (meth)acrylate, o-biphenyloxyethyl (meth)acrylate, o-biphenyloxyethoxyethyl (meth)acrylate, m-biphenyloxyethyl acrylate, p-biphenyloxyethyl (meth)acrylate, and o-biphenyloxyethyl (meth)acrylate. Examples of biphenyl group-containing monomers include oxy-2-hydroxypropyl (meth)acrylate, p-biphenyloxy-2-hydroxypropyl (meth)acrylate, m-biphenyloxy-2-hydroxypropyl (meth)acrylate, N-(meth)acryloyloxyethyl-o-biphenyl=carbamate, N-(meth)acryloyloxyethyl-p-biphenyl=carbamate, N-(meth)acryloyloxyethyl-m-biphenyl=carbamate, o-phenylphenol glycidyl ether acrylate, terphenyl (meth)acrylate, o-terphenyloxyethyl (meth)acrylate, etc. Preferably, 1-adamantyl (meth)acrylate and dicyclopentanyl (meth)acrylate are used. By using these monomers, polymers with high glass transition temperatures can be obtained. These monomers may be used individually or in combination of two or more.

[0068] Furthermore, a silsesquioxane compound having a (meth)acryloyl group may be used instead of the (meth)acrylic acid ester monomer described above. By using a silsesquioxane compound, an acrylic polymer with a high glass transition temperature can be obtained. Silsesquioxane compounds are known to have various skeletal structures, such as cage structures, ladder structures, and random structures. A silsesquioxane compound may have only one of these structures, or it may have two or more. A silsesquioxane compound may be used alone, or two or more may be used in combination.

[0069] As silsesquioxane compounds containing a (meth)acryloyl group, for example, the MAC grade and AC grade of the SQ series from Toagosei Co., Ltd. can be used. MAC grade is a silsesquioxane compound containing a methacryloyl group, and specifically, examples include MAC-SQ TM-100, MAC-SQ SI-20, MAC-SQ HDM, etc. AC grade is a silsesquioxane compound containing an acryloyl group, and specifically, examples include AC-SQ TA-100, AC-SQ SI-20, etc.

[0070] The (meth)acrylic monomer is used in amounts exceeding 50 parts by weight per 100 parts by weight of the monomer mixture.

[0071] <Copolymer Monomer> The monomer represented by formula (1) above is used as the copolymer monomer. By using such a copolymer monomer, a substituent containing boron is introduced into the side chain of the resulting polymer. Only one copolymer monomer may be used, or two or more types may be used in combination.

[0072] Examples of the aliphatic hydrocarbon group in formula (1) above include linear or branched alkyl groups having 1 to 20 carbon atoms, which may have substituents, cyclic alkyl groups having 3 to 20 carbon atoms, which may have substituents, and alkenyl groups having 2 to 20 carbon atoms. Examples of the aryl group above include phenyl groups having 6 to 20 carbon atoms, which may have substituents, and naphthyl groups having 10 to 20 carbon atoms, which may have substituents. Examples of the heterocyclic group include five-membered ring groups or six-membered ring groups containing at least one heteroatom, which may have substituents. １ and R ２ They may be connected to each other to form a ring. １ and R ２ This is preferably a hydrogen atom, or a linear or branched alkyl group having 1 to 3 carbon atoms, and more preferably a hydrogen atom.

[0073] The reactive group contained in the functional group represented by X is at least one selected from the group consisting of vinyl group, (meth)acrylic group, styryl group, (meth)acrylamide group, vinyl ether group, epoxy group, oxetane group, hydroxyl group, amino group, aldehyde group, and carboxyl group. Preferably, the reactive group is a (meth)acrylic group and / or a (meth)acrylamide group. Having these reactive groups can further improve adhesion to the phase difference layer when the resin layer is placed adjacent to the phase difference layer.

[0074] In one embodiment, the functional group represented by X is preferably a functional group represented by Z-Y-. Here, Z represents a functional group comprising at least one reactive group selected from the group consisting of vinyl group, (meth)acrylic group, styryl group, (meth)acrylamide group, vinyl ether group, epoxy group, oxetane group, hydroxyl group, amino group, aldehyde group, and carboxyl group, and Y represents a phenylene group or alkylene group.

[0075] Specifically, the following compounds can be used as copolymer monomers.

[0076] The copolymer monomer is used in an amount greater than 0 parts by weight and less than 50 parts by weight per 100 parts by weight of the monomer mixture. Preferably, it is 0.01 parts by weight or more and less than 50 parts by weight, more preferably 0.05 parts by weight to 20 parts by weight, even more preferably 0.1 parts by weight to 10 parts by weight, and particularly preferably 0.5 parts by weight to 5 parts by weight.

[0077] <Acrylic resin containing lactone rings, etc.> In another embodiment, the acrylic resin may have repeating units containing a ring structure selected from lactone ring units, glutaric acid anhydride units, glutarimide units, maleic acid anhydride units, and maleimide (N-substituted maleimide) units. Only one type of repeating unit containing a ring structure may be included in the repeating units of the acrylic resin, or two or more types may be included. The content of repeating units containing a ring structure in the acrylic resin is preferably 1 mol% to 50 mol%, more preferably 10 mol% to 40 mol%, and even more preferably 20 mol% to 30 mol%. The acrylic resin contains repeating units derived from the above-mentioned (meth)acrylic monomer as the main repeating units.

[0078] <Epoxy Resin> Preferably, an epoxy resin having an aromatic ring is used as the epoxy resin. By using an epoxy resin having an aromatic ring as the epoxy resin, adhesion to the phase difference layer can be improved when the resin layer is placed adjacent to the phase difference layer. Furthermore, when the adhesive layer is placed adjacent to the resin layer, the anchoring force of the adhesive layer can be improved. Examples of epoxy resins having an aromatic ring include bisphenol type epoxy resins such as bisphenol A type epoxy resin, bisphenol F type epoxy resin, and bisphenol S type epoxy resin; novolac type epoxy resins such as phenol novolac epoxy resin, cresol novolac epoxy resin, and hydroxybenzaldehyde phenol novolac epoxy resin; polyfunctional epoxy resins such as glycidyl ether of tetrahydroxyphenylmethane, glycidyl ether of tetrahydroxybenzophenone, and epoxidized polyvinylphenol; naphthol type epoxy resin, naphthalene type epoxy resin, and biphenyl type epoxy resin. Preferably, bisphenol A type epoxy resin, biphenyl type epoxy resin, and bisphenol F type epoxy resin are used. Epoxy resin may be used alone, or two or more types may be used in combination.

[0079] The resin layer can be formed by applying an organic solvent solution of the above resin (for example, an organic solvent solution containing the above resin and the above isocyanate compound) to form a coating film, and then solidifying or thermally curing the coating film. Any suitable organic solvent that can dissolve or uniformly disperse the above resin can be used as the organic solvent. Specific examples of organic solvents include ethyl acetate, toluene, methyl ethyl ketone (MEK), methyl isobutyl ketone (MIBK), cyclopentanone, and cyclohexanone. The resin concentration in the solution is preferably 3 to 20 parts by weight per 100 parts by weight of solvent. With such a resin concentration, a uniform coating film can be formed.

[0080] The above resin solution is applied to the phase difference layer, and the applied film is dried (solidified) or heat-cured to directly form a resin layer on top of the phase difference layer. Any suitable method can be used to apply the resin solution. Specific examples include the roll coating method, spin coating method, wire bar coating method, dip coating method, die coating method, curtain coating method, spray coating method, and knife coating method (comma coating method, etc.).

[0081] The heating temperature of the coated film during drying (solidification) or heat curing is preferably 100°C or lower, and more preferably 50°C to 70°C. Within this heating temperature range, adverse effects on the phase difference layer can be prevented. The heating time may vary depending on the heating temperature. For example, the heating time may be 1 to 10 minutes.

[0082] The resin layer may contain any appropriate additives depending on the purpose. Specific examples of additives include: UV absorbers; leveling agents; antioxidants such as hindered phenols, phosphorus, and sulfur; stabilizers such as light stabilizers, weather stabilizers, and heat stabilizers; reinforcing materials such as glass fibers and carbon fibers; near-infrared absorbers; flame retardants such as tris(dibromopropyl) phosphate, triallyl phosphate, and antimony oxide; antistatic agents such as anionic, cationic, and nonionic surfactants; colorants such as inorganic pigments, organic pigments, and dyes; organic or inorganic fillers; resin modifiers; organic and inorganic fillers; plasticizers; lubricants; antistatic agents; and flame retardants. The type, number, combination, and amount of additives can be appropriately determined depending on the purpose.

[0083] [Adhesive Layer] The first adhesive layer and the second adhesive layer can each be composed of any suitable adhesive. Specific examples include acrylic adhesives, rubber adhesives, silicone adhesives, polyester adhesives, urethane adhesives, epoxy adhesives, and polyether adhesives. By adjusting the type, number, combination, and blending ratio of monomers forming the base resin of the adhesive, as well as the amount of crosslinking agent, reaction temperature, reaction time, etc., an adhesive with desired properties for a particular purpose can be prepared. The base resin of the adhesive may be used alone or in combination of two or more types. Acrylic resins are preferably used as the base resin. Specifically, the adhesive layer is preferably composed of an acrylic adhesive.

[0084] The shear moduli of the first and second adhesive layers at 25°C are, for example, 1.0 × 10⁻⁶. ４ Pa ~ 5.0 x 10 ６ Pa, preferably 5.0 × 10 ４ Pa ~ 1.0 × 10 ６ Pa, more preferably 8.0 × 10 ４ Pa ~ 5.0 x 10 ５ It is Pa.

[0085] The thickness of the first adhesive layer is, for example, 3 μm or more, for example, 15 μm or less, may be 10 μm or less, or may be 7 μm or less. Such a thickness allows for excellent smoothness.

[0086] The thickness of the second adhesive layer is, for example, 3 μm or more, may be 5 μm or more, for example, 25 μm or less, may be 20 μm or less, may be 15 μm or less, or may be 10 μm or less. Such a thickness allows for excellent adhesion to adjacent members.

[0087] [Reflective Polarizing Members] Reflective polarizing members transmit light with polarization parallel to their transmission axis (typically linear polarization) while maintaining its polarization state, and reflect light with other polarization states (typically light with polarization perpendicular to their transmission axis). The orthogonal transmittance (Tc) of a reflective polarizing member may be, for example, 0.01% to 3%. The single-layer transmittance (Ts) of a reflective polarizing member may be, for example, 43% to 49%, preferably 45% to 47%. The degree of polarization (P) of a reflective polarizing member may be, for example, 92% to 99.99%. Reflective polarizing members are typically composed of a multilayer film (sometimes referred to as a reflective polarizing film). Examples of commercially available reflective polarizing films include the product names "DBEF" and "APF" from 3M, and "APCF" from Nitto Denko.

[0088] The above orthogonal transmittance, single-element transmittance, and polarization degree can be measured, for example, using a UV-Vis spectrophotometer. The polarization degree P can be calculated using a UV-Vis spectrophotometer to measure the single-element transmittance Ts, parallel transmittance Tp, and orthogonal transmittance Tc, and then calculated from the obtained Tp and Tc using the following formula. Note that Ts, Tp, and Tc are Y values ​​measured using a 2-degree field of view (C light source) according to JIS Z 8701 and corrected for luminous efficiency. Polarization degree P (%) = {(Tp - Tc) / (Tp + Tc)} １／２ ×100

[0089] [Absorbing Polarizing Member] An absorbing polarizing member typically includes a resin film containing a dichroic substance (sometimes referred to as an absorbing polarizing film), and typically further includes a protective layer disposed on one or both sides thereof.

[0090] The orthogonal transmittance (Tc) of the absorbing polarizing member (absorbing polarizing film) is preferably 0.5% or less, more preferably 0.1% or less, and even more preferably 0.05% or less. The single-element transmittance (Ts) of the absorbing polarizing member (absorbing polarizing film) is, for example, 41.0% to 45.0%, and preferably 42.0% or more. The degree of polarization (P) of the absorbing polarizing member (absorbing polarizing film) is, for example, 99.0% to 99.997%, and preferably 99.9% or more.

[0091] The thickness of the absorption polarizing film is, for example, 1 μm or more and 20 μm or less, but may also 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.

[0092] The above-mentioned absorption polarizing film may be made from a single layer of resin film, or it may be made using a laminate of two or more layers.

[0093] When manufactured from a single layer of resin film, an absorption polarizing film can be obtained by subjecting a hydrophilic polymer film, such as a polyvinyl alcohol (PVA) film, a partially formalized PVA film, or a partially saponified ethylene-vinyl acetate copolymer film, to dyeing treatment with a dichroic substance such as iodine or a dichroic dye, and stretching treatment. Among these, an absorption polarizing film obtained by dyeing a PVA film with iodine and uniaxially stretching it is preferred.

[0094] The above-mentioned iodine dyeing is carried out, for example, by immersing the PVA-based film in an iodine aqueous solution. The stretching ratio for the above-mentioned uniaxial stretching is preferably 3 to 7 times. Stretching may be performed after the dyeing treatment, or during the dyeing process. Alternatively, dyeing may be performed after stretching. If necessary, the PVA-based film may be subjected to swelling treatment, crosslinking treatment, washing treatment, drying treatment, etc.

[0095] When using the above-mentioned laminate of two or more layers, examples of laminates include a laminate of a resin substrate and a PVA-based resin layer (PVA-based resin film) laminated on the resin substrate, or a laminate of a resin substrate and a PVA-based resin layer coated on the resin substrate. An absorption polarizing film obtained using a laminate of a resin substrate and a PVA-based resin layer coated on the resin substrate can be produced, for example, by applying a PVA-based resin solution to a resin substrate, drying it to form a PVA-based resin layer on the resin substrate, and obtaining a laminate of a resin substrate and a PVA-based resin layer; or by stretching and dyeing the laminate to make the PVA-based resin layer an absorption polarizing film. In this embodiment, preferably, a polyvinyl alcohol-based resin layer containing a halogenated compound and a polyvinyl alcohol-based resin is formed on one side of the resin substrate. Stretching typically includes immersing the laminate in an aqueous boric acid solution and stretching it. Furthermore, the stretching may, if necessary, further include air stretching the laminate at a high temperature (e.g., 95°C or higher) before stretching in an aqueous boric acid solution. In addition, in this embodiment, preferably, the laminate is subjected to a drying shrinkage treatment in which it shrinks by 2% or more in the width direction by heating while being transported in the longitudinal direction. Typically, the manufacturing method of this embodiment includes applying an air auxiliary stretching treatment, a dyeing treatment, an underwater stretching treatment, and a drying shrinkage treatment to the laminate in this order. By introducing auxiliary stretching, it is possible to increase the crystallinity of PVA even when PVA is coated on a thermoplastic resin, making it possible to achieve high optical properties. At the same time, by increasing the orientation of PVA in advance, it is possible to prevent problems such as a decrease in the orientation of PVA or dissolution when immersed in water in the subsequent dyeing and stretching processes, making it possible to achieve high optical properties. Furthermore, when the PVA-based resin layer is immersed in a liquid, the disorder of the orientation of polyvinyl alcohol molecules and the decrease in orientation can be suppressed compared to when the PVA-based resin layer does not contain halides. This can improve the optical properties of absorption polarizing films obtained through processing steps that involve immersing the laminate in a liquid, such as dyeing and underwater stretching. Furthermore, the optical properties can be improved by shrinking the laminate in the width direction through a drying shrinkage treatment.The resulting resin substrate / absorbent polarizing film laminate may be used as is (i.e., the resin substrate may be used as a protective layer for the absorbent polarizing film), or an appropriate protective layer may be laminated on the peeled surface obtained by removing the resin substrate from the resin substrate / absorbent polarizing film laminate, or on the surface opposite to the peeled surface, depending on the purpose. Details of such a method for manufacturing an absorbent polarizing film are described, for example, in Japanese Patent Application Publication No. 2012-73580 and Japanese Patent No. 6470455. The entire contents of these publications are incorporated herein by reference.

[0096] The protective layer can be formed from any suitable resin film that can be used as a protective layer for an absorption polarizing film. Specific examples of resins that are the main components of the resin film include cellulosic resins such as triacetylcellulose (TAC), polyester resins, polyvinyl alcohol resins, polycarbonate resins, polyamide resins, polyimide resins, polyethersulfone resins, polysulfone resins, polystyrene resins, cycloolefin resins such as polynorbornene, polyolefin resins, (meth)acrylic resins, acetate resins, and the like.

[0097] The thickness of the protective layer is typically 100 μm or less, for example, 5 μm to 80 μm, preferably 10 μm to 50 μm, and more preferably 15 μm to 35 μm.

[0098] [Protective Member] The protective member preferably comprises a substrate and a surface treatment layer formed on the substrate. The protective member having the surface treatment layer may be positioned such that the surface treatment layer is located on the front side when the optical laminate is applied to a display system. Specifically, the surface treatment layer may be located on the outermost surface of the optical laminate. The surface treatment layer may have any suitable function. The surface treatment layer preferably has an anti-reflective function, for example, from the viewpoint of improving visibility. The thickness of the surface treatment 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.

[0099] [Adhesive Layer] The adhesive layer used for laminating each component (layer) may be formed of an adhesive or a tack. Specifically, the adhesive layer may be an adhesive layer or a tack layer. The thickness of the adhesive layer is, for example, 0.01 μm to 60 μm.

[0100] The adhesive layer is preferably an adhesive layer or a non-curing adhesive layer. An adhesive layer or non-curing adhesive layer that does not undergo curing shrinkage can contribute to improving the smoothness of the optical laminate.

[0101] If the adhesive layer is an adhesive layer, the adhesive constituting the adhesive layer may be the same as the adhesive constituting the first adhesive layer and the second adhesive layer.

[0102] When the adhesive layer is a non-curing adhesive layer, the adhesive constituting the non-curing adhesive layer may include an adhesive containing a solvent and a thermoplastic resin dissolved or dispersed in the solvent. The adhesive may be an aqueous adhesive containing an aqueous solvent, or a solvent-based adhesive containing an organic solvent. An example of an aqueous adhesive is a PVA-based adhesive containing a polyvinyl alcohol-based resin. The thickness of the adhesive layer is, for example, 0.01 μm to 5 μm, preferably 0.1 μm to 4 μm, and more preferably 0.5 μm to 2 μm.

[0103] C. Integrated Member According to another aspect of the present invention, an integrated member is provided which includes a member having a curved surface portion and an optical laminate described in Section B integrated with the member.

[0104] The radius of curvature of the curved portion of a member having a curved surface is, for example, 10 mm or more and 150 mm or less, preferably 100 mm or less, and more preferably 90 mm or less. The radius of curvature can be confirmed, for example, using a laser displacement meter.

[0105] The diameter (major axis) of the curved surface in plan view is, for example, 10 mm to 100 mm. Here, the major axis in plan view is the distance between the two points that are furthest apart on the outer circumference of the curved surface when viewed from above.

[0106] In one embodiment, the member having a curved surface is an optical member such as a lens, and may be, for example, the first lens portion in the display system described in Section A.

[0107] The integration of the optical laminate with the member having a curved surface can be carried out by any suitable method. Figures 5A to 5C are schematic diagrams showing an example of a method for integrating the optical laminate with the curved surface of the member having a curved surface.

[0108] Figure 5A shows the optical laminate cut into the desired shape to prepare the workpiece 4, and the workpiece 4 placed above the adherend (lens) L. In Figure 5A-C, the lens L-side surface of the workpiece 4 may be an adhesive layer.

[0109] The lens L is, for example, circular in plan view and has a concave shape on the upper side in cross-section. The workpiece 4 is held above the concave surface (upper surface) of the lens L by a holder (not shown). In this state, the workpiece 4 can be heated. The workpiece 4 may become more susceptible to deformation due to heating. The plan view shape of the workpiece 4 is not limited to a circle. Specifically, the plan view shape of the workpiece 4 may be approximately elliptical or a rounded rectangle.

[0110] Once the workpiece 4 is in a state where it is easily deformable, it is bonded to the lens L over its entire surface by any appropriate method (for example, by using a pressure difference), as shown in Figure 5B. Then, as shown in Figure 5C, unnecessary parts of the workpiece 4 (for example, parts that do not overlap with the lens L in a plan view) are removed to obtain the integrated member 5. In the illustrated example, the workpiece 4 is integrated to the concave surface of the lens L, but the optical laminate may be integrated to the convex surface of a member having a convex portion.

[0111] As described above, the integration of the optical laminate with the member having a curved surface can be performed while the optical laminate is heated. The temperature of the optical laminate during the above integration is, for example, 80°C to 160°C, preferably 100°C to 140°C. By using an optical laminate in which the occurrence of cracks due to heating is suppressed, an integrated member in which the occurrence of cracks is suppressed can be suitably obtained.

[0112] The present invention will be specifically described below with reference to examples, but the present invention is not limited in any way to these examples. The measurement methods for each characteristic are as follows. Unless otherwise specified, "parts" and "%" in the examples and comparative examples are based on weight.

[0113] <Thickness> Thicknesses of 10 μm or less were measured using a scanning electron microscope (JEOL Ltd., product name "JSM-7100F"). Thicknesses exceeding 10 μm were measured using a digital micrometer (Anritsu Corporation, product name "KC-351C"). <Phase difference value> Phase difference values ​​at each wavelength at 23°C were measured using a phase difference measuring device (Oji Instruments Co., Ltd., "KOBRA"). <Haze> Haze was measured using a haze meter (Suga Test Instruments Co., Ltd., product name "HZ-V3") in accordance with JIS K 7136. <Total light transmittance> Total light transmittance was measured using a haze meter (Suga Test Instruments Co., Ltd., product name "HZ-V3") in accordance with JIS K 7361. <Indentation modulus> The indentation modulus was evaluated by an indentation test using an indentation tester (nanoindenter). Specifically, it is as follows. Acrylic resin solution A was applied to a resin substrate, and dried in the same manner as in Example 1 to obtain a laminate of a thermoset product (thickness 0.4 μm) and a resin substrate. Adhesive composition A was applied to the resin substrate, and cured by UV irradiation in the same manner as in Comparative Example 2 to obtain a laminate of adhesive layer A and a resin substrate. These laminates were used as measurement samples, and nanoindentation measurements were performed on the cured products under the following conditions. (Measurement conditions) ・Measurement device: Hystron Inc., product name "Triboindenter" ・Indenter used: Berkovich (triangular pyramidal type) ・Measurement method: Single indentation measurement ・Measurement temperature: Room temperature (approx. 25°C) ・Indentation depth setting: 50 nm The indentation modulus (S√π / 2√A) was calculated from the measurement results using the software (triboscan) attached to the measurement device (S: contact stiffness, A: contact projected area). The average value of N=3 was taken as the indentation modulus. <Shear Modulus> The shear modulus was evaluated by dynamic viscoelasticity measurement in the shear mode using a dynamic viscoelasticity measuring device (TA Instruments "ARES"). Specifically, the following was performed: A test sample with a thickness of 1 mm was prepared by laminating only the adhesive layer to be measured. This test sample was punched out into a disc shape with a diameter of 7.9 mm, sandwiched between parallel plates, and dynamic viscoelasticity measurement was performed under the following conditions. From the measurement results, the shear modulus G' of the adhesive layer at a predetermined temperature was read.(Measurement conditions) Deformation mode: Torsion Measurement frequency: 1 Hz Temperature range: -50°C to 150°C Heating rate: 5°C / min Shape: Parallel plate 7.9 mmφ <Glass transition temperature (Tg)> The glass transition temperature of the resin was measured using a differential scanning calorimeter (DSC6220, manufactured by SII Nanotechnology Co., Ltd.). Approximately 10 mg of resin sample was placed in an aluminum pan manufactured by the same company and sealed, and heated from 30°C to 200°C at a heating rate of 20°C / min under a nitrogen gas flow of 50 mL / min. After holding the temperature for 3 minutes, it was cooled to 30°C at a rate of 20°C / min. It was held at 30°C for 3 minutes, and then heated again to 200°C at a rate of 20°C / min. From the DSC data obtained during the second heating cycle, the extrapolated glass transition onset temperature was determined by finding the temperature at the intersection of a straight line extending the low-temperature baseline towards the high-temperature side and a tangent line drawn at the point where the slope of the curve representing the stepwise transition of the glass transition is maximized. This temperature was defined as the glass transition temperature (Tg).

[0114] [Manufacturing Example 1: Preparation of λ / 4 component A] 55 parts of the compound represented by formula (I) below, 25 parts of the compound represented by formula (II) below, and 20 parts of the compound represented by formula (III) below were added to 400 parts of cyclopentanone (CPN). The mixture was then heated to 60°C and stirred to dissolve. After dissolution was confirmed, the mixture was returned to room temperature, and 3 parts of Irgacure 907 (manufactured by BASF Japan Ltd.), 0.2 parts of Megafac F-554 (manufactured by DIC Corporation), and 0.1 parts of p-methoxyphenol (MEHQ) were added. The mixture was further stirred to obtain a solution. The solution was transparent and homogeneous. The obtained solution was filtered through a 0.20 μm membrane filter to obtain a polymerizable composition. The polyimide solution for alignment films was applied to a glass substrate with a thickness of 0.7 mm using a spin coating method, dried at 100°C for 10 minutes, and then baked at 200°C for 60 minutes to obtain a coating film. The obtained coating film was subjected to a rubbing treatment using a commercially available rubbing device to form an orientation film. The polymerizable composition obtained above was applied to the orientation film (substrate) by spin coating and dried at 100°C for 2 minutes. After the obtained coating film was cooled to room temperature, it was heated using a high-pressure mercury lamp at 30 mW / cm². ２A liquid crystal alignment solidified layer with a thickness of 3 μm was obtained by irradiating with ultraviolet light at the specified intensity for 30 seconds. The obtained liquid crystal alignment solidified layer (λ / 4 member A) had an in-plane phase difference Re(550) of 141 nm and a Re(450) / Re(550) of 0.80, exhibiting inverse dispersion wavelength characteristics.

[0115]

[0116] [Manufacturing Example 2: Preparation of Positive C Plate] A liquid crystal coating solution was prepared by dissolving 20 parts by weight of a side-chain liquid crystal polymer represented by the following chemical formula (IV) (the numbers 65 and 35 in the formula indicate the mole percent of monomer units and are conveniently represented as a block polymer: weight-average molecular weight 5000), 80 parts by weight of a polymerizable liquid crystal exhibiting a nematic liquid crystal phase (BASF Japan Ltd.: trade name Paliocolor LC242), and 5 parts by weight of a photopolymerization initiator (Ciba Specialty Chemicals: trade name Irgacure 907) in 200 parts by weight of cyclopentanone. The coating solution was then applied to a vertically aligned PET substrate using a bar coater, and the liquid crystal was aligned by heating and drying at 80°C for 4 minutes. By irradiating this liquid crystal layer with ultraviolet light to cure the liquid crystal layer, a positive C plate A with a thickness of 4 μm, Re(550) of 0 nm, and Rth(550) of -80 nm was formed on the substrate.

[0117] [Production Example 3: Preparation of Adhesive Layer] A monomer mixture containing 92 parts by weight of butyl acrylate, 5 parts by weight of N-acryloylmorpholine, 2.9 parts by weight of acrylic acid, and 0.1 parts by weight of 2-hydroxyethyl acrylate was charged into a four-necked flask equipped with a stirring blade, thermometer, nitrogen gas inlet tube, and condenser. Furthermore, 0.1 parts by weight of 2,2'-azobisisobutyronitrile was added to 100 parts by weight of this monomer mixture as a polymerization initiator along with 100 parts by weight of ethyl acetate. After introducing nitrogen gas while gently stirring to purge the flask with nitrogen, the polymerization reaction was carried out for 8 hours while maintaining the liquid temperature in the flask at around 55°C to prepare a solution of an acrylic polymer with a weight-average molecular weight (Mw) of 2 million. To 100 parts by weight of the solid content of the above-mentioned acrylic polymer solution, 0.15 parts by weight of dibenzoyl peroxide (half-life of 1 minute: 130°C) and 0.6 parts by weight of a polyisocyanate crosslinking agent (Coronate L, manufactured by Nippon Polyurethane Industry Co., Ltd.) consisting of a trimethylolpropane adduct of tolylene diisocyanate were mixed to prepare an acrylic adhesive. The obtained acrylic adhesive was coated onto a substrate film, and the resulting coating film on the substrate film was dried in an oven to form an adhesive layer A with a thickness of 5 μm (shear modulus: 0.13 MPa).

[0118] [Manufacturing Example 4: Preparation of Adhesive Composition] Adhesive composition A was prepared by mixing 62 parts by weight of hydroxyethyl acrylamide (manufactured by Kojinsha, trade name "HEAA"), 25 parts by weight of acryloylmorpholine (manufactured by Kojinsha, trade name "ACMO"), 7 parts by weight of PEG400# diacrylate (manufactured by Kyoeisha Chemical Co., Ltd., trade name "Light Acrylate 9EG-A"), 3 parts by weight of "Irgacure 907" (manufactured by BASF Japan) and 3 parts by weight of "KAYACURE DETX-S" (manufactured by Nippon Kayaku Co., Ltd.) for 60 minutes.

[0119] [Production Example 5: Preparation of Acrylic Resin Solution] 99.0 parts by weight of methyl methacrylate (MMA, manufactured by Fujifilm Wako Pure Chemical Industries, trade name: methyl methacrylate monomer), 1.0 part by weight of monomer of general formula (1e), and 0.2 parts by weight of polymerization initiator (manufactured by Fujifilm Wako Pure Chemical Industries, trade name: 2,2'-azobis(isobutyronitrile)) were dissolved in 100 parts by weight of toluene. Then, a polymerization reaction was carried out for 5.5 hours while heating at 70°C under a nitrogen atmosphere to obtain copolymer 1 (solid content concentration: 50% by weight). The Tg of copolymer 1 was 105°C and the Mw was 85000. To 70 parts (on a solids basis) of the obtained copolymer 1 (boron-containing acrylic resin), 22.5 parts (on a solids basis) of trimethylolpropane adduct of tolylene diisocyanate (manufactured by Tosoh Corporation, trade name "Coronate L") and 7.5 parts (on a solids basis) of trimethylolpropane adduct of hexamethylene diisocyanate (manufactured by Mitsui Chemicals, trade name "Takenate D160N") were added as isocyanate compounds to obtain a mixture. This mixture was dissolved in 80 parts of a mixed solvent of ethyl acetate / cyclopentanone (70 / 30) to obtain acrylic resin solution A (20%).

[0120] [Example 1] The acrylic resin solution A obtained in Production Example 5 was applied to the surface of the positive C plate A of a laminate having the configuration [substrate / positive C plate A] obtained in Production Example 2. The coating film was dried at 60°C for 5 minutes to directly form a resin layer A (thickness 0.04 μm, indentation modulus 6000 MPa), which is composed of a thermoset product of the coating film of the acrylic resin organic solvent solution, on the surface of the positive C plate A. Next, the λ / 4 member A obtained in Production Example 1 was transferred from the glass substrate to the surface of the resin layer A via the adhesive layer A. The substrate was peeled off from the positive C plate to obtain an optical laminate 1 having the configuration [positive C plate A / resin layer A / adhesive layer A / λ / 4 member A].

[0121] [Comparative Example 1] An optical laminate 1C having the configuration of [positive C plate A / adhesive layer A / λ / 4 member A] was obtained in the same manner as in Example 1, except that a resin layer A was not formed on the surface of the positive C plate A.

[0122] [Comparative Example 2] The adhesive composition A obtained in Production Example 4 was applied to the surface of the positive C plate A of the laminate having the configuration [substrate / positive C plate A] obtained in Production Example 2. The laminate having the configuration [substrate / λ / 4 member A] obtained in Production Example 1 was laminated on the coated film so that the λ / 4 member A was on the coated film side. The resulting laminate was irradiated with UV light to cure the adhesive composition and form an adhesive layer A (thickness 1 μm, indentation modulus 1.0 MPa). Next, the substrate was peeled off from the positive C plate A and the λ / 4 member A to obtain an optical laminate 2C having the configuration [positive C plate A / adhesive layer A / λ / 4 member A].

[0123] <Characteristic Evaluation> The smoothness, haze, total light transmittance, and Re(550) of the optical laminates obtained in the above examples and comparative examples were measured. For the haze, total light transmittance, and Re(550), the measurement was performed from the λ / 4 member A side using a sample prepared by bonding the surface of the positive C plate A of the optical laminate to a glass plate via another adhesive layer A. The smoothness was evaluated as follows. The results are shown in Table 1. ・Smoothness The smoothness of the laminate was measured using a phase-shift laser interferometer (manufactured by Zygo, product name "DynaFiz"). Specifically, the optical laminate was laminated onto a microslide glass (manufactured by Matsunami Glass Industry Co., Ltd., product name "S200200") to prevent the inclusion of foreign matter, air bubbles, and deformation streaks. Lamination was performed via adhesive layer A so that the positive C plate A was on the microslide glass side. Next, degassing was performed using a pressurized degassing device (autoclave) to remove the effects of minute air bubbles. The degassing conditions were 50°C, 0.5 MPa, and 30 minutes. After degassing, the sample was allowed to cool at room temperature for at least 30 minutes to obtain the measurement sample. The measurement sample was placed on a measurement platform with vibration isolation, and a single-wavelength (wavelength 633 nm) laser was used to interfere with a standard instrument with guaranteed flatness, and the relative displacement within a predetermined area (a circle with a diameter of 30 mm) was measured. For the analysis, the laminate smoothness (unit: arcmin) was defined as twice the value of the angle index "Slope magnitude RMS" obtained by extracting frequency values ​​from 0.1 / mm to 1 / mm (corresponding to 2σ).

[0124]

[0125] <Heating Test> The evaluation sample was a reflective polarizing film (manufactured by Nitto Denko Corporation, "APCF", thickness 58 μm) laminated onto the surface of the λ / 4 member A of the optical laminate obtained in the above examples and comparative examples via an adhesive layer A (size 50 mm x 30 mm). The lamination was performed so that the angle between the slow axis of the λ / 4 member A and the reflection axis of the reflective polarizing film was 45 degrees. As shown in Figure 6, both short sides of the evaluation sample S were attached to the glass G with imide tape T, leaving a 3 cm x 3 cm area unfixed. The evaluation sample in this state was placed in a heating oven at 120°C. After 15 minutes, it was removed and the presence or absence of cracks was checked by microscopic observation (N = 2 or 4). The number of samples in which cracks occurred is shown in Table 2.

[0126]

[0127] <Load Test> The optical laminates obtained in the above examples and comparative examples were cut into squares with a side length of 40 mm, and a reflective polarizing film (manufactured by Nitto Denko Corporation, "APCF", thickness 58 μm) was laminated onto the λ / 4 member A surface via an optically transparent adhesive layer (thickness 10 μm). The lamination was performed so that the angle between the slow axis of the λ / 4 member A and the reflection axis of the reflective polarizing film was 45 degrees. The obtained laminate was bonded to a glass plate via an acrylic adhesive layer (thickness 30 μm) so that the surface of the positive C plate A was facing the glass plate side to obtain an evaluation sample. The evaluation sample was placed with the glass plate facing down, and loads of 300 g, 500 g, or 700 g were applied to a total of five locations on the surface of the reflective polarizing film: the center and the four corners, using a pencil with a flattened tip (hardness H). (Indentation Evaluation) After removing the load, the surface of the evaluation sample (specifically, the surface of the reflective polarizing film) was observed to check whether an indentation had occurred. The minimum load at which an indentation occurred is shown in Table 3. (Cross-Transmission Evaluation) After removing the load, linearly polarized light, whose reflection axis and polarization direction are perpendicular to that of the reflective polarizing film, was incident on either the reflective polarizing film side or the glass plate side, and it was checked from the opposite side to see if any light leakage occurred at the location where the load had been applied. Five samples were evaluated, and if three or more samples showed light leakage, they were judged as "defective". The minimum load at which a sample was judged as defective is shown in Table 3. (Reflection Evaluation) After removing the load, linearly polarized light, whose reflection axis and polarization direction coincide with that of the reflective polarizing film, was incident on the reflective polarizing film side, and it was checked from the opposite side to see if any light leakage occurred at the location where the load had been applied. Five samples were evaluated, and if three or more samples showed light leakage, they were judged as "defective". The minimum load at which a sample was judged as defective is shown in Table 3.

[0128]

[0129] As shown in Tables 1 to 3, the optical laminates of the embodiments in which the phase difference layer, resin layer, and adhesive layer were provided adjacent to each other exhibited excellent surface smoothness, crack resistance, and load-bearing capacity.

[0130] An optical laminate according to an embodiment of the present invention can be suitably used, for example, in the manufacture of a display device that includes a curved surface component such as VR goggles.

[0131] 2 Display system, 12 Display element, 14 Reflective polarizing member, 16 First lens section, 18 Half mirror, 20 First phase difference member, 22 Second phase difference member, 22a First phase difference layer, 22b Second phase difference layer, 24 Second lens section, 30 Resin layer, 100A-100C Optical laminate

Claims

1. An optical laminate comprising a phase difference layer, a resin layer, and an adhesive layer in that order, wherein the resin layer contains a thermoplastic resin.

2. The optical laminate according to claim 1, wherein the resin layer is disposed directly adjacent to the phase difference layer.

3. The optical laminate according to claim 1, wherein the indentation modulus of the resin layer is greater than the shear modulus of the adhesive layer.

4. The indentation modulus of the resin layer at 25°C is 5.0 × 10⁻⁶. ８ The optical laminate according to claim 1, wherein the hardness is Pa or greater.

5. The optical laminate according to claim 1, wherein the ratio of the indentation modulus of the resin layer at 25°C to the shear modulus of the adhesive layer at 25°C is 10 or more.

6. The optical laminate according to claim 1, wherein the thickness of the resin layer is 1 μm or less.

7. The optical laminate according to claim 1, wherein the phase difference layer is an orientation solidified layer of a liquid crystal compound.

8. The optical laminate according to claim 1, wherein the phase difference layer is a homeotropically oriented solidified layer of a liquid crystal compound.

9. An integrated member comprising a member having a curved surface portion and an optical laminate according to claim 1 integrated with the curved surface portion of the member.

10. The integrated member according to claim 9, wherein the radius of curvature of the curved portion is 10 mm to 150 mm.

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