Image display device and method for manufacturing an image display device

Abstract

To provide an image display device and a method for manufacturing an image display device that can improve the conformability of an optical laminate to a three-dimensional curved surface. [Solution] An image display device according to an embodiment of the present invention comprises a transparent member, an optical laminate, and an image display panel. The transparent member has a three-dimensional curved surface. The optical laminate is attached to the three-dimensional curved surface. The image display panel is located on the opposite side of the optical laminate from the three-dimensional curved surface. The optical laminate comprises a first adhesive layer, a polarizer, and a second adhesive layer. The first adhesive layer is in contact with the three-dimensional curved surface. The second adhesive layer is in contact with the image display panel. The image display device satisfies the following formula (1). R 2 ×(d1+d2) / 1000>310···(1) (In equation (1), R represents the radius of curvature of the three-dimensional curved surface [mm], d1 represents the thickness of the first adhesive layer [μm], and d2 represents the thickness of the second adhesive layer [μm].)

Description

[Technical Field]

[0001] The present invention relates to an image display device and a method for manufacturing an image display device. [Background technology]

[0002] Conventionally, image display devices, such as liquid crystal displays and electroluminescent (EL) displays (e.g., organic EL displays and inorganic EL displays), have rapidly become widespread. It is known that optical laminates comprising a phase difference film and a polarizer can be applied to such image display devices in order to impart desired optical properties (see, for example, Patent Document 1). [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2024-124169 [Overview of the project] [Problems that the invention aims to solve]

[0004] In recent years, the applications of image display devices have expanded. Consequently, the shapes of image display devices have diversified, and some may have three-dimensional curved surfaces that are not developable. The manufacture of image display devices with three-dimensional curved surfaces is being explored by attaching optical laminates to such devices, or by forming the three-dimensional curved surface after attaching the optical laminate to the image display device. However, it is difficult to form a three-dimensional curved surface using an optical laminate as described in Patent Document 1, and there is a risk that the optical laminate may not be able to adequately conform to the three-dimensional curved surface in an image display device. The main objective of the present invention is to provide an image display device and a method for manufacturing an image display device that can improve the conformability of an optical laminate to a three-dimensional curved surface. [Means for solving the problem]

[0005] [1] An image display device according to an embodiment of the present invention comprises a transparent member, an optical laminate, and an image display panel. The transparent member has a three-dimensional curved surface. The optical laminate is attached to the three-dimensional curved surface. The image display panel is located on the opposite side of the optical laminate from the three-dimensional curved surface. The optical laminate comprises a first adhesive layer, a polarizer, and a second adhesive layer. The first adhesive layer is in contact with the three-dimensional curved surface. The polarizer is located on the opposite side of the first adhesive layer from the three-dimensional curved surface relative to the first adhesive layer. The second adhesive layer is located on the opposite side of the polarizer from the first adhesive layer. The second adhesive layer is in contact with the image display panel. The image display device satisfies the following formula (1). R 2 ×(d1+d2) / 1000>310···(1) (In equation (1), R represents the radius of curvature of the three-dimensional curved surface [mm], d1 represents the thickness of the first adhesive layer [μm], and d2 represents the thickness of the second adhesive layer [μm].) [2] In the image display device described in [1] above, the sum of the thickness d1 of the first adhesive layer and the thickness d2 of the second adhesive layer may be greater than 150 μm and less than 500 μm. [3] In the image display device described in [1] or [2] above, the thickness d1 of the first adhesive layer may be greater than 250 μm and less than 500 μm. [4] In the image display device described in any of [1] to [3] above, the thickness d2 of the second adhesive layer may be 10 μm or more and less than 50 μm. [5] In the image display device described in any of [1] to [4] above, the thickness d1 of the first adhesive layer may exceed the sum of the thickness d2 of the second adhesive layer, the thickness d3 of the polarizer, and the thickness d4 of the image display panel. [6] In the image display device described in any of [1] to [5] above, the thickness d1 of the first adhesive layer may exceed the sum of the thickness d2 of the second adhesive layer and the thickness d3 of the polarizer. [7] In the image display device described in any of [1] to [6] above, the image display panel may be curved along the three-dimensional curved surface. The radius of curvature of the image display panel may be smaller than the radius of curvature of the three-dimensional curved surface. [8] In the image display device described in [7] above, the radius of curvature of the image display panel may be greater than 2 mm and less than 100 mm. [9] In the image display device described in [7] or [8] above, the radius of curvature of the image display panel may be greater than 2 mm and less than 65 mm.

[10] In the image display device described in any of [7] to [9] above, the radius of curvature of the image display panel may be greater than 2 mm and less than 45 mm.

[11] In the image display device described in any of [1] to

[10] above, the optical laminate may further comprise a first phase difference film. The first phase difference film is located between the first adhesive layer and the polarizer. The radius of curvature of the first phase difference film is greater than the radius of curvature of the polarizer.

[12] In the image display device described in

[11] above, the first phase difference film may function as a λ / 4 plate.

[13] An image display device according to any of [1] to

[12] above may further include a second phase difference film. The second phase difference film is located between the polarizer and the second adhesive layer. The radius of curvature of the second phase difference film is smaller than the radius of curvature of the polarizer.

[14] A method for manufacturing an image display device according to another aspect of the present invention includes, in this order: preparing an optical laminate comprising a polarizer and a second adhesive layer in this order; attaching the optical laminate to an image display panel by the second adhesive layer; and attaching the optical laminate to a three-dimensional curved surface of a transparent member by the first adhesive layer. The method for manufacturing an image display device satisfies the following formula (1). 2500>R 2 ×(d1+d2) / 1000>310···(1) (In formula (1), R represents the radius of curvature [mm] of the three-dimensional curved surface, d1 represents the thickness [μm] of the first adhesive layer, and d2 represents the thickness [μm] of the second adhesive layer).

[15] A method for manufacturing an image display device according to another aspect of the present invention includes the steps of preparing an optical laminate including a polarizer and a second adhesive layer in this order; attaching the optical laminate to an image display panel with the second adhesive layer; attaching the optical laminate to a transparent member with a first adhesive layer; and forming the transparent member into a three-dimensional curved surface in a state where the image display panel and the optical laminate are attached to the transparent member, in this order. In the method for manufacturing the image display device, the following formula (1) is satisfied. 2500 > R 2 ×(d1 + d2) / 1000 > 310 ··· (1) (In formula (1), R represents the radius of curvature [mm] of the three-dimensional curved surface, d1 represents the thickness [μm] of the first adhesive layer, and d2 represents the thickness [μm] of the second adhesive layer).

Advantages of the Invention

[0006] According to an embodiment of the present invention, the followability of the optical laminate with respect to the three-dimensional curved surface can be improved.

Brief Description of the Drawings

[0007] [Figure 1] FIG. 1 is a schematic configuration diagram of an image display device according to one embodiment of the present invention. [Figure 2] FIG. 2 is a schematic cross-sectional view of an optical laminate included in the image display device of FIG. 1. [Figure 3] FIG. 3 is a schematic cross-sectional view of a second retardation film included in the optical laminate of FIG. 2. [Figure 4] FIG. 4 is a schematic cross-sectional view of an optical laminate included in an image display device according to another embodiment of the present invention.

Modes for Carrying Out the Invention

[0008] Hereinafter, representative embodiments of the present invention will be described, but the present invention is not limited to these embodiments. Also, for the purpose of making the description clearer, the drawings may schematically represent the width, thickness, shape, etc. of each part compared to the embodiments, but this is merely an example and does not limit the interpretation of the present invention.

[0009] (Definition of Terms and Symbols) The definitions of the terms and symbols in this specification are as follows. (1) Refractive Index (nx, ny, nz) “nx” is the refractive index in the direction where the in-plane refractive index is maximum (i.e., the slow axis direction), “ny” is the refractive index in the direction orthogonal to the slow axis in the plane (i.e., the fast axis direction), 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 λ nm at 23°C. For example, “Re(550)” is the in-plane phase difference measured with light of wavelength 550 nm at 23°C. Re(λ) is obtained by the formula: Re(λ) = (nx - ny) × d when the thickness of the layer (film) is d (nm). (3) Phase Difference in the Thickness Direction (Rth) “Rth(λ)” is the phase difference in the thickness direction measured with light of wavelength λ nm at 23°C. For example, “Rth(550)” is the phase difference in the thickness direction measured with light of wavelength 550 nm at 23°C. Rth(λ) is obtained by the formula: Rth(λ) = (nx - nz) × d when the thickness of the layer (film) is d (nm). (4) Nz Coefficient The Nz coefficient is obtained by Nz = Rth / Re. (5) Angle When referring to an angle in this specification, the angle includes both clockwise and counterclockwise with respect to the reference direction. Therefore, for example, “45°” means ±45°.

[0010] A. Outline of the Image Display Device Figure 1 is a schematic diagram of an image display device according to one embodiment of the present invention, and Figure 2 is a schematic cross-sectional view of the optical laminate included in the image display device of Figure 1. As shown in Figures 1 and 2, in one embodiment, the image display device 100 comprises a transparent member 2, an optical laminate 1, and an image display panel 3. The transparent member 2 has a three-dimensional curved surface 21. The optical laminate 1 is attached to the three-dimensional curved surface 21. The image display panel 3 is located on the opposite side of the optical laminate 1 from the three-dimensional curved surface 21. The optical laminate 1 comprises a first adhesive layer 11, a polarizer 13, and a second adhesive layer 12 in this order. The first adhesive layer 11 is in contact with the three-dimensional curved surface 21. The polarizer 13 is located on the opposite side of the three-dimensional curved surface 21 from the first adhesive layer 11. The second adhesive layer 12 is located on the opposite side of the first adhesive layer 11 from the polarizer 13. The second adhesive layer 12 is in contact with the image display panel 3. The image display device 100 satisfies the following equation (1). R 2 ×(d1+d2) / 1000>310···(1) (In equation (1), R represents the radius of curvature of the three-dimensional curved surface [mm], d1 represents the thickness of the first adhesive layer [μm], and d2 represents the thickness of the second adhesive layer [μm].) The inventors of the present invention were investigating the application of an optical laminate to an image display device having a three-dimensional curved surface, and discovered that the thickness of the adhesive layer of the optical laminate affects the conformability of the optical laminate to the three-dimensional curved surface. Therefore, the present inventors diligently investigated the thickness of the adhesive layer of the optical laminate and found that if a specific relationship is satisfied between the radius of curvature of the three-dimensional curved surface and the thickness of the adhesive layer, the conformability of the optical laminate to the three-dimensional curved surface can be improved. More specifically, if the image display device satisfies the above formula (1), the optical laminate can be stably formed into a three-dimensional curved surface (specifically, by attaching the optical laminate to a three-dimensional curved surface, or by attaching the optical laminate to a transparent member and then forming it into a three-dimensional curved surface), and the optical laminate can be made to conform sufficiently to the three-dimensional curved surface.

[0011] The image display device 100 preferably satisfies the following formula (1-1), more preferably satisfies the following formula (1-2), and even more preferably satisfies the following formula (1-3). 2500>R 2 ×(d1+d2) / 1000>310···(1-1) 2000>R 2 ×(d1+d2) / 1000>330···(1-2) 1500>R 2 ×(d1+d2) / 1000>400···(1-3) (In equations (1-1) to (1-3), R represents the radius of curvature of the three-dimensional curved surface [mm], d1 represents the thickness of the first adhesive layer [μm], and d2 represents the thickness of the second adhesive layer [μm].) With this configuration, the conformability of the optical laminate to a three-dimensional curved surface can be further improved, and the optical laminate can be formed more stably on a three-dimensional curved surface.

[0012] The radius of curvature R of the three-dimensional curved surface 21 of the transparent member 2 is, for example, 200 mm or less, or for example, 100 mm or less, or for example, 80 mm or less, or for example, 60 mm or less, or for example, 40 mm or less. Even if the three-dimensional curved surface has such a radius of curvature, if the image display device satisfies the above formula (1), the optical laminate can be molded to conform to the three-dimensional curved surface. On the other hand, the radius of curvature R of the three-dimensional curved surface 21 of the transparent member 2 is, for example, 2 mm or more, or for example, 10 mm or more, or for example, 20 mm or more. The radius of curvature of a three-dimensional curved surface can be measured, for example, by a laser interferometer, laser displacement meter, spectroscopic interferometer, or scanning electron microscope (SEM).

[0013] The sum of the thickness d1 of the first adhesive layer 11 and the thickness d2 of the second adhesive layer 12 is, for example, 50 μm or more, preferably 100 μm or more, more preferably exceeding 150 μm, and even more preferably 200 μm or more. On the other hand, the sum of the thickness d1 of the first adhesive layer 11 and the thickness d2 of the second adhesive layer 12 is, for example, 600 μm or less, preferably less than 500 μm, more preferably 400 μm or less, and even more preferably 350 μm or less. When the total thickness of the first adhesive layer and the second adhesive layer is within this range, the image display device can stably satisfy the above formula (1).

[0014] The thickness d1 of the first adhesive layer 11 is, for example, 50 μm or more, preferably 80 μm or more, more preferably 120 μm or more, even more preferably 180 μm or more, particularly preferably 220 μm or more, especially preferably exceeding 250 μm, and most preferably 280 μm or more. On the other hand, the thickness d1 of the first adhesive layer 11 is, for example, 600 μm or less, preferably less than 500 μm, and more preferably 400 μm or less. When the first adhesive layer has such a thickness, the optical laminate can be stably attached to a three-dimensional curved surface.

[0015] The thickness d2 of the second adhesive layer 12 is, for example, 5 μm or more, preferably 10 μm or more, more preferably exceeding 15 μm, even more preferably 20 μm or more, and particularly preferably 25 μm or more. On the other hand, the thickness d2 of the second adhesive layer 12 is, for example, 60 μm or less, preferably less than 50 μm, and more preferably 40 μm or less. Having such a thickness in the second adhesive layer allows the optical laminate to be more stably attached to a three-dimensional curved surface.

[0016] The thickness d1 of the first adhesive layer 11 may exceed the sum of the thickness d2 of the second adhesive layer 12 and the thickness d3 of the polarizer 13, or it may be less than or equal to the sum of the thickness d2 of the second adhesive layer 12 and the thickness d3 of the polarizer 13. In one embodiment, the thickness d1 of the first adhesive layer 11 exceeds the sum of the thickness d2 of the second adhesive layer 12 and the thickness d3 of the polarizer 13. With this configuration, the handling of the first adhesive layer can be improved, and the durability of the optical laminate can be improved. The thickness d1 of the first adhesive layer 11 is, for example, 1.1 to 50 times, preferably 3 to 35 times, and more preferably 5 to 20 times, the sum of the thickness d2 of the second adhesive layer 12 and the thickness d3 of the polarizer 13.

[0017] The thickness d1 of the first adhesive layer 11 may exceed the sum of the thickness d2 of the second adhesive layer 12, the thickness d3 of the polarizer 13, and the thickness d4 of the image display panel 3, or it may be less than or equal to the sum of the thickness d2 of the second adhesive layer 12, the thickness d3 of the polarizer 13, and the thickness d4 of the image display panel 3. In one embodiment, the thickness d1 of the first adhesive layer 11 exceeds the sum of the thickness d2 of the second adhesive layer 12, the thickness d3 of the polarizer 13, and the thickness d4 of the image display panel 3. With such a configuration, the handling of the first adhesive layer can be further improved, and the durability of the optical laminate can be stably improved. The thickness d1 of the first adhesive layer 11 is, for example, 1.1 to 10 times, preferably 1.2 to 6.5 times, and more preferably 1.3 to 3 times, the sum of the thickness d2 of the second adhesive layer 12, the thickness d3 of the polarizer 13, and the thickness d4 of the image display panel 3.

[0018] The thickness d3 of the polarizer 13 is, for example, 1 μm to 80 μm, preferably 1 μm to 15 μm, more preferably 1 μm to 12 μm, and even more preferably 3 μm to 8 μm. Having such a thickness in the polarizer allows for a thinner optical laminate, which in turn allows for a smaller image display device.

[0019] The thickness d4 of the image display panel 3 is, for example, 20 μm to 200 μm, preferably 25 μm to 100 μm, and more preferably 30 μm to 50 μm. Having such a thickness in the image display panel allows for stable miniaturization of the image display device.

[0020] As shown in FIG. 2, in one embodiment, the optical laminate 1 further includes a first retardation film 14. The first retardation film 14 is located between the first adhesive layer 11 and the polarizer 13. In the illustrated example, the first retardation film 14 is in contact with the first adhesive layer 11.

[0021] Typically, the first retardation film 14 can function as a protective layer for the polarizer 13. The first retardation film 14 may have an in-plane retardation or a retardation in the thickness direction. The first retardation film 14 may function as a λ / 4 plate, or may function as a λ / 2 plate, a λ / 5 plate, a λ / 6 plate, or a C-Plate.

[0022] In one embodiment, the first retardation film 14 has an in-plane retardation. The refractive indices of the first retardation film 14 exhibit a relationship of, for example, nx > ny ≧ nz, and preferably nx > ny > nz. Note that "ny = nz" includes not only the case where ny and nz are exactly equal, but also the case where they are substantially equal. Therefore, within a range that does not impair the effects of the present invention, ny > nz or ny < nz may occur. In the illustrated example, the first retardation film 14 functions as a λ / 4 plate. According to such a configuration, in an image display device, it is possible to improve the visibility through an optical member having a polarization effect (hereinafter sometimes referred to as a polarizing member).

[0023] The in-plane retardation Re(550) of the first retardation film 14 is, for example, 80 nm or more, and 90 nm or more. On the other hand, the in-plane retardation Re(550) of the first retardation film 14 is, for example, 160 nm or less, preferably 145 nm or less, more preferably 130 nm or less, still more preferably 120 nm or less, and particularly preferably 110 nm or less. When the first retardation film has such Re(550), in an image display device, the visibility through the polarizing member can be stably improved, and a desired coloring can be stably exhibited.

[0024] The phase difference Rth(550) in the thickness direction of the first phase difference film 14 is, for example, 80 nm to 200 nm, and preferably 90 nm to 160 nm. The Nz coefficient of the first phase difference film 14 is, for example, 0.5 to 5.0, and preferably 1.0 to 3.0.

[0025] The first phase difference film 14 having an in-plane phase difference may exhibit inverse wavelength dispersion characteristics in which the in-plane birefringence increases with the wavelength of the measurement light, or it may exhibit positive wavelength dispersion characteristics in which the in-plane birefringence decreases with the wavelength of the measurement light, or it may exhibit flat wavelength dispersion characteristics in which the in-plane birefringence hardly changes with the wavelength of the measurement light.

[0026] The thickness d5 of the first phase difference film 14 is, for example, 10 μm or more, preferably 15 μm or more, and more preferably 20 μm or more. If the thickness of the first phase difference film is above this lower limit, the first phase difference film can function stably as a protective layer for the polarizer. On the other hand, the thickness d5 of the first phase difference film 14 is, for example, 80 μm or less, preferably 60 μm or less, and more preferably 50 μm or less. If the thickness of the first phase difference film is below this upper limit, the optical laminate can be made thinner.

[0027] The angle between the slow phase axis direction of the first phase difference film 14 and the absorption axis direction of the polarizer 13 is, for example, 30° to 60°, preferably 35° to 55°, more preferably 40° to 50°, and even more preferably 43° to 47°. With this configuration, the visibility of an image display device can be more stably improved through the polarizing member.

[0028] The first phase difference film 14 is typically attached to the polarizer 13 via an adhesive layer 17. Hereinafter, the adhesive layer that attaches the first phase difference film 14 to the polarizer 13 may be referred to as the first adhesive layer 17a. The first adhesive layer 17a may be an adhesive layer or a tack layer.

[0029] In one embodiment, the first adhesive layer 17a is an adhesive layer. In other words, the first adhesive layer 17a contains a cured product of any suitable adhesive. Examples of adhesives include water-based adhesives, thermosetting adhesives, moisture-curing adhesives, and active energy ray-curing adhesives such as ultraviolet-curing adhesives (UV adhesives), with active energy ray-curing adhesives being preferred. Adhesives can be used alone or in combination.

[0030] The thickness of the first adhesive layer 17a is, for example, 15 μm or less, preferably 10 μm or less, and more preferably 5 μm or less. On the other hand, the lower limit of the thickness of the first adhesive layer 17a is typically 0.5 μm.

[0031] In one embodiment, the optical laminate 1 further comprises a second phase difference film 15. The second phase difference film 15 is located between the polarizer 13 and the second adhesive layer 12. In the illustrated example, the second phase difference film 15 is in contact with the second adhesive layer 12.

[0032] The second phase difference film 15 may have an in-plane phase difference, or it may have a phase difference in the thickness direction. The second phase difference film 15 may function as a λ / 4 plate, or it may function as a λ / 2 plate, a λ / 3 plate, a λ / 5 plate, or a C-Plate.

[0033] In one embodiment, the second phase difference film 15 has an in-plane phase difference. The refractive index of the second phase difference film 15 exhibits, for example, the relationship nx > ny, preferably nx > nz ≥ ny. The second phase difference film 15 may be a combination of multiple phase difference films. Multiple phase difference films exhibiting the relationship nx > ny may be combined. Phase difference films exhibiting the relationships nx > ny and nx = ny may be combined. In the illustrated example, the second phase difference film 15 functions as a λ / 4 plate. With this configuration, the image display device can be given excellent anti-reflective properties.

[0034] The in-plane phase difference Re(550) of the second phase difference film 15 is, for example, 100 nm to 300 nm, preferably 100 nm to 190 nm, more preferably 110 nm to 170 nm, and even more preferably 130 nm to 160 nm. The Nz coefficient of the second phase difference film 15 is, for example, 0.3 to 1.5, and preferably 0.9 to 1.3.

[0035] The second phase difference film 15 having an in-plane phase difference may exhibit inverse wavelength dispersion characteristics in which the in-plane birefringence increases with the wavelength of the measurement light, or it may exhibit positive wavelength dispersion characteristics in which the in-plane birefringence decreases with the wavelength of the measurement light, or it may exhibit flat wavelength dispersion characteristics in which the in-plane birefringence hardly changes with the wavelength of the measurement light.

[0036] The thickness d6 of the second phase difference film 15 is, for example, 15 μm or less, preferably less than 10 μm, and more preferably 5 μm or less. On the other hand, the lower limit of the thickness d6 of the second phase difference film 15 is typically 1 μm. Having such a thickness in the second phase difference film allows for a thinner optical laminate.

[0037] The optical laminate 1 may further include a protective layer 16. The protective layer 16 is located between the polarizer 13 and the second adhesive layer 12. In the illustrated example, the protective layer 16 is located between the polarizer 13 and the second phase difference film 15. With this configuration, the protective layer can stably protect the polarizer.

[0038] The thickness d7 of the protective layer 16 is, for example, 5 mm or less, preferably 1 mm or less, more preferably 1 μm to 500 μm, even more preferably 5 μm to 150 μm, and more preferably 10 μm to 40 μm.

[0039] In the illustrated example, the protective layer 16 is attached to the polarizer 13 via the adhesive layer 17, and also attached to the second phase difference film 15 via the adhesive layer 17. Hereinafter, the adhesive layer that attaches the protective layer 16 to the polarizer 13 may be referred to as the second adhesive layer 17b, and the adhesive layer that attaches the protective layer 16 to the second phase difference film 15 may be referred to as the third adhesive layer 17c. The second adhesive layer 17b and the third adhesive layer 17c will be described in the same manner as the first adhesive layer 17a described above. Therefore, a detailed description of the second adhesive layer 17b and the third adhesive layer 17c will be omitted.

[0040] The optical laminate 1 has any suitable shape when viewed from the stacking direction. The shape of the optical laminate 1 as viewed from the stacking direction can be, for example, a polygonal shape such as a rectangle, a circular shape, an elliptical shape, or other irregular shapes. The shape of the optical laminate 1 is adjusted according to the shape of the image display device having a three-dimensional curved surface. Among the shapes of the optical laminate 1 as viewed from the stacking direction, a rectangular shape is preferred. The size of the optical laminate 1 is adjusted arbitrarily and appropriately.

[0041] B. Details of the image display device Next, with reference to Figures 1 and 2, the details of an optical laminate according to one embodiment will be described. As shown in Figure 1, the image display device 100 comprises the transparent member 2 described above, the optical laminate 1 described above, and the image display panel 3 described above.

[0042] B-1. Transparent component The transparent component 2 is typically capable of transmitting light with wavelengths of 410 nm to 650 nm. The total light transmittance of the transparent member 2 at a wavelength of 590 nm is, for example, 80% to 99%, preferably 90% to 98%. Examples of the transparent component 2 include a front panel such as a cover glass, a lens, and a decorative film.

[0043] The transparent member 2 is provided with a three-dimensional curved surface 21 having the radius of curvature R described above. The three-dimensional curved surface 21 may be a concave surface or a convex surface. In the illustrated example, the three-dimensional curved surface 21 is a concave surface and is provided on the surface of the transparent member 2 on the side of the image display panel 3.

[0044] B-2. Optical laminate The optical laminate 1 is typically flexible. The optical laminate 1 is attached to the three-dimensional curved surface 21 of the transparent member 2 by a first adhesive layer 11. As a result, at least a portion of the optical laminate 1 is curved along the three-dimensional curved surface 21 and is formed into a three-dimensional curved surface. In the illustrated example, the entire optical laminate 1 is curved along the three-dimensional curved surface 21.

[0045] As shown in Figure 2, in one embodiment, the optical laminate 1 comprises, in this order, the first adhesive layer 11, the first phase difference film 14, the first adhesive layer 17a, the polarizer 13, the second adhesive layer 17b, the protective layer 16, the third adhesive layer 17c, the second phase difference film 15, and the second adhesive layer 12. With the optical laminate 1 attached to the three-dimensional curved surface 21, the first phase difference film 14, polarizer 13, protective layer 16, and second phase difference film 15 are each curved along the three-dimensional curved surface 21 (see Figure 1).

[0046] B-2-1. First adhesive layer The first adhesive layer 11 is typically located at one end in the stacking direction of the optical laminate 1. When the optical laminate 1 is attached to the three-dimensional curved surface 21, the first adhesive layer 11 is in contact with the three-dimensional curved surface 21. The first adhesive layer 11 is typically capable of transmitting light with wavelengths of 410 nm to 650 nm. The total light transmittance of the first adhesive layer 11 at a wavelength of 590 nm is, for example, 80% to 95%, and also, for example, 85% to 93%.

[0047] The first adhesive layer 11 is composed of any suitable adhesive (adhesive composition). Adhesive compositions typically contain a base polymer. Examples of base polymers include (meth)acrylic polymers, silicone polymers, polyesters, polyurethanes, polyamides, polyvinyl ethers, vinyl acetate / vinyl chloride copolymers, modified polyolefins, epoxy polymers, fluorinated polymers, natural rubber, and synthetic rubber. Note that "(meth)acrylic" refers to acrylic and / or methacrylic polymers. The base polymers can be used alone or in combination.

[0048] In one embodiment, the first adhesive layer 11 comprises an acrylic adhesive composition containing a (meth)acrylic polymer as a base polymer. With such a configuration, the optical transparency of the first adhesive layer can be improved, and adhesive properties such as appropriate wettability, cohesiveness, and adhesion can be stably imparted to the first adhesive layer. The content of the (meth)acrylic polymer is, for example, 50% by mass or more, preferably 70% by mass or more, and more preferably 90% by mass or more, in the solid content of the acrylic adhesive composition.

[0049] The (meth)acrylic polymer preferably has a crosslinked structure. More specifically, the (meth)acrylic polymer includes (meth)acrylic polymer chains into which a crosslinked structure has been introduced.

[0050] (Meth)acrylic polymers contain structural units derived from alkyl (meth)acrylates. Alkyl (meth)acrylates with 1 to 20 carbon atoms in the alkyl group are preferably used. The alkyl (meth)acrylate may have branched alkyl groups or cyclic alkyl groups. The proportion of constituent units derived from alkyl (meth)acrylate is, for example, 50% by mass or more, preferably 55% by mass or more, and more preferably 60% by mass or more, relative to the total amount of constituent units of the (meth)acrylic polymer chain. The proportion of constituent units derived from alkyl(meth)acrylate having a chain-like alkyl group with 4 to 10 carbon atoms is, for example, 40% by mass or more, preferably 50% by mass or more, and more preferably 55% by mass or more, relative to the total amount of constituent units of the (meth)acrylic polymer chain. When the proportion of constituent units derived from alkyl(meth)acrylate is within this range, the glass transition temperature (Tg) of the polymer chain can be appropriately adjusted. Note that the total amount of constituent units of a (meth)acrylic polymer chain refers to the total monomer components that make up the polymer, excluding the monomers used to form the crosslinked structure (such as the polyfunctional (meth)acrylate and urethane (meth)acrylate described later) and the crosslinking agent.

[0051] The (meth)acrylic polymer may further contain constituent units derived from copolymer monomers, depending on the purpose. Specific examples of copolymer monomers include vinyl monomers such as hydroxyl group-containing monomers, carboxyl group-containing monomers, nitrogen-containing monomers, acid anhydride group-containing monomers, caprolactone adducts of (meth)acrylic acid, sulfonic acid group-containing monomers, phosphoric acid group-containing monomers, vinyl acetate, vinyl propionate, styrene, and α-methylstyrene; cyano group-containing acrylic monomers such as acrylonitrile and methacrylonitrile; epoxy group-containing monomers such as glycidyl (meth)acrylate; glycol-based acrylic ester monomers such as polyethylene glycol (meth)acrylate, polypropylene glycol (meth)acrylate, methoxyethylene glycol (meth)acrylate, and methoxypolypropylene glycol (meth)acrylate; and acrylic acid ester monomers such as tetrahydrofurfuryl (meth)acrylate, fluorine (meth)acrylate, silicone (meth)acrylate, and 2-methoxyethyl (meth)acrylate. By adjusting the number, type, combination, and amount of copolymer monomer components, an adhesive layer with desired properties for a specific purpose can be obtained.

[0052] Polymers in which a crosslinked structure has been introduced into the (meth)acrylic polymer chain can be obtained, for example, by (1) polymerizing a (meth)acrylic polymer having a functional group that can react with a crosslinking agent, then adding the crosslinking agent and reacting the (meth)acrylic polymer with the crosslinking agent; and (2) introducing a branched structure (crosslinked structure) into the polymer chain by including a polyfunctional compound in the polymerization components of the polymer. These methods may be used in combination.

[0053] Specific examples of crosslinking agents in the method of reacting the base polymer and crosslinking agent described in (1) above include isocyanate-based crosslinking agents, epoxy-based crosslinking agents, oxazoline-based crosslinking agents, aziridine-based crosslinking agents, carbodiimide-based crosslinking agents, and metal chelate-based crosslinking agents. Crosslinking agents can be used alone or in combination. Among the crosslinking agents, isocyanate-based crosslinking agents and epoxy-based crosslinking agents are preferred. When the crosslinking agent contains an isocyanate-based crosslinking agent and / or an epoxy-based crosslinking agent, it reacts sufficiently with functional groups such as hydroxyl groups and carboxyl groups introduced into the base polymer, and a crosslinked structure can be smoothly formed.

[0054] In the method of including a polyfunctional compound as the polymerization component of the base polymer described in (2) above, the entire amount of monomer components constituting the (meth)acrylic polymer and the polyfunctional compound for introducing the crosslinking structure may be reacted at once, or polymerization may be carried out in multiple steps. An example of a multi-step polymerization method is to polymerize (prepolymerize) the monofunctional monomers constituting the (meth)acrylic polymer to prepare a partially polymerized product (prepolymer composition), and then add a polyfunctional compound such as a polyfunctional (meth)acrylate to the prepolymer composition to polymerize the prepolymer composition and the polyfunctional monomer (main polymerization). The prepolymer composition is a partially polymerized product containing a polymer with a low degree of polymerization and unreacted monomers. Examples of polyfunctional compounds include compounds containing two or more polymerizable functional groups (ethylenically unsaturated groups) having unsaturated double bonds in one molecule. As polyfunctional compounds, polyfunctional (meth)acrylates are preferred because copolymerization with monomer components of (meth)acrylic polymers is easy. When introducing a branched (crosslinked) structure by active energy ray polymerization (photopolymerization), polyfunctional (meth)acrylates are preferred. Furthermore, by using urethane (meth)acrylates having (meth)acryloyl groups at the ends of urethane chains as polyfunctional (meth)acrylates, a crosslinked structure by urethane segments can be introduced.

[0055] In one embodiment, the adhesive composition may contain an acrylic oligomer. In one embodiment, the adhesive composition may be photocurable. In this case, the adhesive composition may contain, for example, a polyfunctional compound and a photopolymerization initiator.

[0056] The adhesive composition may contain additives. Specific examples of additives include powders such as colorants and pigments, dyes, surfactants, plasticizers, tackifiers, surface lubricants, leveling agents, softeners, antioxidants, anti-aging agents, light stabilizers, UV absorbers, polymerization inhibitors, conductive agents, inorganic or organic fillers, metal powders, particulate matter, and foil-like materials. Furthermore, a redox system with a reducing agent may be employed within a controllable range. The type, number, combination, and amount of additives can be appropriately set according to the purpose. By appropriately adjusting the type, combination, and amount of monomer components, as well as the type, number, combination, and amount of crosslinking agents, silane coupling agents, and additives, an adhesive composition (and consequently, an adhesive layer) with desired properties for the purpose can be obtained.

[0057] Another example of an adhesive composition constituting the adhesive layer is described in Japanese Patent Publication No. 2016-94569. The description in said publication is incorporated herein by reference.

[0058] The glass transition temperature of the first adhesive layer 11 is, for example, -3°C or lower, preferably -5°C or lower, and more preferably -6°C or lower. On the other hand, the glass transition temperature of the first adhesive layer 11 is, for example, -20°C or higher, preferably -15°C or higher, and more preferably -13°C or higher. If the glass transition temperature is within such a range, an adhesive layer having excellent impact resistance can be realized.

[0059] The peak top value of the loss tangent tanδ of the first adhesive layer 11 (that is, tanδ at the glass transition temperature) is, for example, 1.5 or higher, preferably 1.6 or higher, more preferably 1.7 or higher, and even more preferably 1.75 or higher. On the other hand, the peak top value of tanδ of the first adhesive layer 11 is, for example, 3.0 or lower, preferably 2.5 or lower, and more preferably 2.3 or lower.

[0060] The gel fraction of the first adhesive layer 11 is, for example, 50% to 95%, preferably 55% to 93%, and more preferably 60% to 90%. If the gel fraction is within such a range, the transparent member and the optical laminate can be firmly fixed. The gel fraction is calculated as, for example, the insoluble component in a solvent such as ethyl acetate. Specifically, the gel fraction is determined as the mass fraction (unit: mass%) of the insoluble component after immersing the adhesive constituting the adhesive layer in ethyl acetate at 23°C for 7 days with respect to the sample before immersion.

[0061] The storage modulus of the first adhesive layer 11 at 25°C is, for example, 1×10 4 Pa to 30×10 4 Pa, preferably 2×10 4 Pa to 25×10 4 Pa, and more preferably 3×10 4 Pa to 20×10 4 Pa. The storage modulus of the adhesive layer is measured, for example, in accordance with JIS K 6868 at a heating rate of 5°C / min and a frequency of 1 Hz.

[0062] B-2-2. First phase difference film The first phase difference film 14 is typically flexible. With the optical laminate 1 attached to the three-dimensional curved surface 21, at least a portion of the first phase difference film 14 is curved along the three-dimensional curved surface 21 (see Figure 1). In one embodiment, the radius of curvature of the first phase difference film 14 is greater than the radius of curvature of the polarizer 13. The radius of curvature of the first phase difference film 14 (more specifically, the radius of curvature of the curved portion of the first phase difference film 14) is, for example, 1 mm to 200 mm, and preferably 2 mm to 100 mm. The radius of curvature of each film (layer) is measured, for example, by a laser interferometer, laser displacement meter, spectroscopic interferometer, or SEM.

[0063] The first phase difference film 14 typically includes a stretched film prepared by stretching a resin film, and / or an orientation solidified layer of a liquid crystal compound. In this specification, "orientation-solidified layer of liquid crystal compound" refers to a layer in which liquid crystal compounds are oriented in a predetermined direction within the layer, and this orientation state is fixed. Furthermore, the concept of "orientation-solidified layer" encompasses the orientation-cured layer obtained by curing liquid crystal monomers, as described later.

[0064] The first phase difference film 14 may have a single-layer structure or a laminated structure. In one embodiment, the first phase difference film 14 has a single-layer structure. The first phase difference film 14, which has a single-layer structure, is typically composed of a stretched film having the in-plane phase difference described above. Examples of materials for the stretched film include cycloolefin (COP) resins, cellulose resins, polycarbonate (PC) resins, and (meth)acrylic resins, with COP resins and cellulose resins being preferred. Polynorbornene resins are a specific example of COP-type resins. A specific example of a cellulosic resin is triacetylcellulose (TAC). The materials for the stretched film can be used individually or in combination. In one embodiment, the first phase difference film 14 having a single-layer structure contains a COP-based resin.

[0065] A surface treatment layer is optionally provided on the surface of the first phase difference film 14 having a single-layer structure. Examples of surface treatment layers include a hard coat layer, an anti-reflective layer, an anti-sticking layer, and an anti-glare treatment layer. Preferably, the surface treatment layer is provided on the surface of the first phase difference film 14 opposite to the polarizer 13.

[0066] B-2-3.Polarizer The polarizer 13 is typically flexible. With the optical laminate 1 attached to the three-dimensional curved surface 21, at least a portion of the polarizer 13 is curved along the three-dimensional curved surface 21 (see Figure 1). The radius of curvature of the polarizer 13 (more specifically, the radius of curvature of the curved portion of the polarizer 13) is, for example, 1 mm to 200 mm, and preferably 2 mm to 100 mm.

[0067] The polarizer 13 has any suitable configuration. For example, the polarizer may be composed of a single layer of resin film, or it may be obtained using a laminate of two or more layers.

[0068] Specific examples of polarizers composed of a single layer of resin film include hydrophilic polymer films such as polyvinyl alcohol (PVA) resin films, partially formalized PVA resin films, and partially saponified ethylene-vinyl acetate copolymer films, which have been subjected to dyeing and stretching treatments with dichroic substances such as iodine or dichroic dyes, as well as polyene-based oriented films such as dehydrated PVA or dehydrochlorinated polyvinyl chloride. Preferably, polarizers obtained by dyeing a PVA resin film with iodine and uniaxially stretching are used because they have excellent optical properties.

[0069] Specific examples of polarizers obtained using laminates include polarizers obtained using a laminate of a resin substrate and a PVA-based resin layer (PVA-based resin film) laminated on the resin substrate, or polarizers obtained using a laminate of a resin substrate and a PVA-based resin layer coated on the resin substrate. Polarizers 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 the resin substrate and the PVA-based resin layer; or by stretching and dyeing the laminate to make the PVA-based resin layer a polarizer. In one embodiment, a polyvinyl alcohol-based resin layer containing a halide 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, stretching may further include, if necessary, air-stretching the laminate at a high temperature (e.g., 95°C or higher) before stretching in the aqueous boric acid solution. In addition, in one embodiment, 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-assisted stretching treatment, a dyeing treatment, a water-based 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 and 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 makes it possible to improve the optical properties of polarizers obtained through processing steps that involve immersing the laminate in a liquid, such as dyeing and water-based stretching. Furthermore, by shrinking the laminate in the width direction through the drying shrinkage treatment, the optical properties can be improved.The resulting resin substrate / polarizer laminate may be used as is (i.e., the resin substrate may be used as a protective layer for the polarizer), or the resin substrate may be peeled off from the resin substrate / polarizer laminate, and any appropriate protective layer may be laminated onto the peeled surface according to the purpose. Details of the manufacturing method of such polarizers are described, for example, in Japanese Patent Publication No. 2012-73580 and Japanese Patent No. 6470455. The entire contents of these publications are incorporated herein by reference.

[0070] The above-mentioned iodine dyeing is carried out, for example, by immersing the PVA resin 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 resin film may be subjected to swelling treatment, crosslinking treatment, washing treatment, drying treatment, etc. For example, by immersing the PVA resin film in water and washing it before dyeing, not only can dirt and blocking inhibitors on the surface of the PVA resin film be washed away, but the PVA resin film can also be swollen to suppress uneven dyeing.

[0071] The polarizer 13 typically exhibits absorption dichroism at any wavelength between 380 nm and 780 nm. The transmittance of the polarizer 13 alone is, for example, 41.5% to 46.0%, preferably 43.0% to 46.0%, and more preferably 44.5% to 46.0%. The degree of polarization of the polarizer 3 is preferably 97.0% or higher, more preferably 99.0% or higher, and even more preferably 99.9% or higher.

[0072] B-2―4.Protective layer The protective layer 16 is typically flexible. With the optical laminate 1 attached to the three-dimensional curved surface 21, at least a portion of the protective layer 16 is curved along the three-dimensional curved surface 21 (see Figure 1). In one embodiment, the radius of curvature of the protective layer 16 is smaller than the radius of curvature of the polarizer 13. The radius of curvature of the protective layer 16 (more specifically, the radius of curvature of the curved portion of the protective layer 16) is, for example, 1 mm to 200 mm, and preferably 2 mm to 100 mm.

[0073] The protective layer 16 contains any suitable transparent resin. Examples of transparent resins include cycloolefin (COP) resins such as polynorbornene; polyester resins such as polyethylene terephthalate (PET); cellulose resins such as triacetylcellulose (TAC); polycarbonate (PC) resins; (meth)acrylic resins; polyvinyl alcohol resins; polyamide resins; polyimide resins; polyethersulfone resins; polysulfone resins; polystyrene resins; polyolefin resins; and acetate resins. Other examples include thermosetting resins such as (meth)acrylic, urethane, (meth)acrylic-urethane, epoxy, and silicone resins, as well as UV-curing resins. In addition, glassy polymers such as siloxane polymers can also be used. A polymer film described in Japanese Patent Application Publication No. 2001-343529 (WO01 / 37007) can also be used. As a material for the protective layer, for example, a resin composition containing a thermoplastic resin having substituted or unsubstituted imide groups in its side chains and a thermoplastic resin having substituted or unsubstituted phenyl and nitrile groups in its side chains can be used. For example, a resin composition having an alternating copolymer of isobutene and N-methylmaleimide and an acrylonitrile-styrene copolymer can be used. The polymer film may be, for example, an extruded product of the above resin composition. The protective layer materials can be used individually or in combination.

[0074] B-2-5. Second phase difference film The second phase difference film 15 is typically flexible. With the optical laminate 1 attached to the three-dimensional curved surface 21, at least a portion of the second phase difference film 15 is curved along the three-dimensional curved surface 21 (see Figure 1). In one embodiment, the radius of curvature of the second phase difference film 15 is smaller than the radius of curvature of the polarizer 13. In the illustrated example, the radius of curvature of the second phase difference film 15 is smaller than the radius of curvature of the protective layer 16. The radius of curvature of the second phase difference film 15 (more specifically, the radius of curvature of the curved portion of the second phase difference film 15) is, for example, 1 mm to 200 mm, and preferably 2 mm to 100 mm.

[0075] The second phase difference film 15 has any suitable configuration. The second phase difference film 15 typically includes a stretched film prepared by stretching a resin film, and / or an orientation solidified layer of a liquid crystal compound.

[0076] In one embodiment, the second phase difference film 15 includes an orientation solidification layer of a liquid crystal compound. If the second phase difference film contains an orientation solidification layer of a liquid crystal compound, the difference between nx and ny of the second phase difference film can be made significantly larger compared to non-liquid crystal materials, thus significantly reducing the thickness of the phase difference film having the desired in-plane phase difference. As a result, the optical laminate can be made even thinner.

[0077] The second phase difference film 15 may have a single-layer structure or a laminated structure. In one embodiment, the second phase difference film 15 has a laminated structure. More specifically, the second phase difference film 15 includes an orientation solidification layer of a plurality of liquid crystal compounds.

[0078] As shown in Figure 3, in one embodiment, the second phase difference film 15 comprises two orientation solidification layers of liquid crystal compounds. Hereinafter, the two orientation solidification layers of liquid crystal compounds in the second phase difference film 15 may be referred to as the first liquid crystal orientation solidification layer 151 and the second liquid crystal orientation solidification layer 152.

[0079] The first liquid crystal alignment solidification layer 151 is located between the polarizer 13 and the second liquid crystal alignment solidification layer 152 (see Figure 1). In the illustrated example, the first liquid crystal alignment solidification layer 151 is located between the protective layer 16 and the second liquid crystal alignment solidification layer 152 (see Figure 1). Therefore, the first liquid crystal alignment solidification layer 151 is attached to the protective layer 16 via the third adhesive layer 17c. The second liquid crystal alignment solidification layer 152 is located on the opposite side of the polarizer 13 from the first liquid crystal alignment solidification layer 151 (see Figure 1).

[0080] The first liquid crystal alignment solidification layer 151 typically functions as a λ / 2 plate. The second liquid crystal alignment solidification layer 152 typically functions as a λ / 4 plate. With this configuration, the wavelength dispersion characteristics of the second phase difference film can be brought closer to ideal inverse wavelength dispersion characteristics. Therefore, excellent anti-reflective properties can be imparted to the optical laminate. Furthermore, the first liquid crystal alignment solidification layer 151 may function as a λ / 4 plate, and the second liquid crystal alignment solidification layer 152 may function as a λ / 2 plate.

[0081] The angle between the absorption axis direction of the polarizer 13 and the slow phase axis direction of the first liquid crystal alignment solidification layer 151 is, for example, 10° to 20°, preferably 12° to 18°, and more preferably 14° to 16°. Furthermore, the angle between the absorption axis direction of the polarizer 13 and the slow phase axis direction of the second liquid crystal alignment solidification layer 152 is, for example, 70° to 80°, preferably 72° to 78°, and more preferably 74° to 76°. With this configuration, the wavelength dispersion characteristics of the second phase difference film 15 can be brought closer to ideal inverse wavelength dispersion characteristics. Therefore, excellent anti-reflective properties can be stably imparted to the optical laminate. Furthermore, the range of angles between the absorption axis direction of the polarizer and the slow axis direction of the second liquid crystal alignment solidification layer may be reversed from the range of angles between the absorption axis direction of the polarizer and the slow axis direction of the third liquid crystal alignment solidification layer.

[0082] In the first liquid crystal alignment solidification layer 151, typically, rod-shaped liquid crystal compounds are oriented in a state where they are aligned along the slow phase axis of the first liquid crystal alignment solidification layer 151 (homogenous orientation). Examples of liquid crystal compounds include liquid crystal compounds in which the liquid crystal phase is a nematic phase (nematic liquid crystals). Examples of such liquid crystal compounds include liquid crystal polymers and liquid crystal monomers. Liquid crystal polymers and liquid crystal monomers may be used individually or in combination. The mechanism by which liquid crystalline properties are expressed in liquid crystal compounds may be lyotropic or thermotropic.

[0083] When a liquid crystal compound contains a liquid crystal monomer, the liquid crystal monomer is preferably a polymerizable monomer or a crosslinkable monomer. The orientation state of the liquid crystal monomer can be fixed by polymerizing or crosslinking (i.e., curing) the liquid crystal monomer. After oriented the liquid crystal monomer, the orientation state can be fixed by polymerizing or crosslinking the liquid crystal monomers together, for example. Here, polymerization forms a polymer and crosslinking forms a three-dimensional network structure, but these are non-liquid crystal. Therefore, the formed first liquid crystal orientation solidified layer does not undergo transitions to liquid crystal phase, glass phase, or crystalline phase due to temperature changes, which is characteristic of liquid crystal compounds. As a result, the second phase difference film can have extremely excellent stability that is not affected by temperature changes.

[0084] Any suitable liquid crystal monomer can be used. Examples of liquid crystal monomers include polymerizable mesogenic compounds described in Japanese Patent Publication No. 2002-533742 (WO00 / 37585), EP358208 (US5211877), EP66137 (US4388453), WO93 / 22397, EP0261712, DE19504224, DE4408171, and GB2280445. Specific examples of such polymerizable mesogenic compounds include BASF's trade name LC242, Merck's trade name E7, and Wacker-Chem's trade name LC-Silicon-CC3767.

[0085] An orientation-solidified layer of liquid crystal compounds can be formed by applying an appropriate orientation treatment to the surface of any suitable coated substrate, then applying a coating liquid containing a liquid crystal compound to the surface to orient the liquid crystal compound in the direction corresponding to the orientation treatment, and fixing that orientation state. Orientation treatments include, for example, mechanical orientation treatments, physical orientation treatments, and chemical orientation treatments. Specific examples of liquid crystal compounds and details of the method for forming the orientation solidified layer are described in Japanese Patent Publication No. 2006-163343. The description in said publication is incorporated herein by reference.

[0086] The thickness of the first liquid crystal alignment solidification layer 151 is arbitrarily and appropriately adjusted so that a desired in-plane phase difference is obtained. The thickness of the first liquid crystal alignment solidification layer 151 is, for example, 5 μm or less, preferably 3 μm or less, and more preferably 2 μm or less. On the other hand, the lower limit of the thickness of the first liquid crystal alignment solidification layer 151 is typically 1.0 μm.

[0087] The second liquid crystal alignment solidification layer 152 will be described in the same manner as the first liquid crystal alignment solidification layer 151. Therefore, a detailed explanation of the second liquid crystal alignment solidification layer 152 will be omitted as appropriate. In the illustrated example, the second liquid crystal alignment solidification layer 152 is attached to the first liquid crystal alignment solidification layer 151 via an adhesive layer 153. The adhesive layer 153 will be described in the same way as the first adhesive layer 17a described above. Therefore, a detailed explanation of the adhesive layer 153 will be omitted.

[0088] B-2-6.Second adhesive layer As shown in Figure 2, the second adhesive layer 12 is typically located at the end opposite to the first adhesive layer 11 in the optical laminate 1. In one embodiment, the second adhesive layer 12 is provided on the surface of the second phase difference film 15 opposite to the polarizer 13.

[0089] The second adhesive layer 12 is composed of any suitable adhesive. Examples of adhesives that make up the second adhesive layer 12 include those similar to those used in the first adhesive layer 11.

[0090] The storage modulus of the second adhesive layer 12 at 25°C is, for example, 2 × 10⁻⁶. 4 Pa~16×10 4 Pa is preferably 4 × 10 4 Pa~15×10 4 It is Pa.

[0091] B-2-7. Variations As described above, the optical laminate 1 shown in Figure 2 comprises a protective layer 16 and a second phase difference film 15. However, the configuration of the optical laminate 1 is not limited to this. As shown in Figure 4, in one embodiment, the image display device 100 may include only one of the protective layer 16 and the second phase difference film 15. That is, the optical laminate 1 shown in Figure 4 includes the first adhesive layer 11, the first phase difference film 14, the first adhesive layer 17a, the polarizer 13, the second adhesive layer 17b, the second phase difference film 15 or protective layer 16, and the second adhesive layer 12 in this order. With such a configuration, the optical laminate can be made thinner.

[0092] B-3. ​​Image display panel As shown in Figure 1, the image display panel 3 includes an image display cell corresponding to the image display device 100. The image display panel 3 is typically flexible. The image display panel 3 is attached to the surface of the second adhesive layer 12 opposite to the polarizer 13 (see Figure 2). With the optical laminate 1 attached to the three-dimensional curved surface 21 and the image display panel 3 attached to the second adhesive layer 12, at least a portion of the image display panel 3 is curved along the three-dimensional curved surface 21. The radius of curvature of the image display panel 3 is typically smaller than the radius of curvature of the three-dimensional curved surface 21. In the illustrated example, the radius of curvature of the image display panel 3 is smaller than the radii of curvature of the first phase difference film 14, the polarizer 13, the second phase difference film 15, and the protective layer 16 (see Figure 2).

[0093] The radius of curvature of the image display panel 3 (more specifically, the radius of curvature of the curved portion of the image display panel 3) is, for example, 1 mm or more, preferably exceeding 2 mm, and more preferably 10 mm or more. On the other hand, the radius of curvature of the image display panel 3 (more specifically, the radius of curvature of the curved portion of the image display panel 3) is, for example, 200 mm or less, preferably less than 100 mm, more preferably less than 65 mm, even more preferably less than 45 mm, and particularly preferably 30 mm or less.

[0094] C. Method for manufacturing an image display device Next, a method for manufacturing an optical laminate according to one embodiment will be described. In one embodiment, the method for manufacturing an image display device includes, in this order, the steps of: preparing the optical laminate 1 described above; attaching the optical laminate 1 to the image display panel 3 with a second adhesive layer 12; and attaching the optical laminate 1 to the three-dimensional curved surface 21 of the transparent member 2 with a first adhesive layer 11. In other words, in this embodiment, the optical laminate 1 (hereinafter sometimes referred to as the laminate with the panel) with the image display panel 3 attached is attached to the three-dimensional curved surface 21 of the transparent member 2. More specifically, the laminate with the panel is heated to, for example, 50°C to 120°C to bring the first adhesive layer 11 of the laminate with the panel into contact with the three-dimensional curved surface 21. In this method, the radius of curvature R of the three-dimensional curved surface, the thickness d1 of the first adhesive layer, and the thickness d2 of the second adhesive layer satisfy equation (1) above, so the laminate with the panel bends smoothly to conform to the three-dimensional curved surface and is stably attached to the three-dimensional curved surface. This is how image display devices are manufactured.

[0095] Furthermore, in the method for manufacturing an image display device described above, an optical laminate is attached to a transparent member having a three-dimensional curved surface, but the method for manufacturing an image display device is not limited to this. In another embodiment, the method for manufacturing an image display device includes, in this order, the steps of: preparing the optical laminate 1 described above; attaching the optical laminate 1 to the image display panel 3 with a second adhesive layer 12; forming a three-dimensional curved surface on the image display panel 3 and the optical laminate 1 (specifically, the laminate with a panel); and attaching it to a transparent member 2 having a three-dimensional curved surface 21 with a first adhesive layer 11. The transparent member 2 may have its three-dimensional curved surface 21 formed in the step of attaching it to the image display panel 3 and the optical laminate 1 (specifically, the laminate with a panel), or it may have its three-dimensional curved surface 21 formed in advance. In yet another embodiment, the method for manufacturing an image display device includes, in this order, the steps of: preparing the optical laminate 1 described above; attaching the optical laminate 1 to the image display panel 3 with a second adhesive layer 12; attaching the optical laminate 1 to the transparent member 2 with a first adhesive layer 11; and forming a three-dimensional curved surface 21 on the transparent member 2 while the image display panel 3 and the optical laminate 1 (specifically, the laminate with the panel) are attached to the transparent member 2. In other words, in this embodiment, the laminated panel is attached to a transparent member 2 that does not have a three-dimensional curved surface, and then the transparent member 2 to which the laminated panel is attached is processed to form a three-dimensional curved surface 21. Examples of processing methods for forming three-dimensional curved surfaces include heat molding, press molding, stretch molding, and shrink molding. During the processing to form a three-dimensional curved surface, the laminated panel and / or transparent component are heated to, for example, 50°C to 120°C. Even with this method, the radius of curvature R of the three-dimensional curved surface, the thickness d1 of the first adhesive layer, and the thickness d2 of the second adhesive layer satisfy equation (1) above, so the laminate with the panel deforms to follow the transparent member, and a three-dimensional curved surface can be stably formed on the image display device. In these embodiments, the pre-prepared optical laminate 1 may or may not include the first adhesive layer 11. If the pre-prepared optical laminate 1 does not include the first adhesive layer 11, the first adhesive layer 11 is formed on one end of the optical laminate 1 in the stacking direction (on the first phase difference film 14 in the illustrated example) after the optical laminate 1 has been attached to the image display panel 3 by the second adhesive layer 12.

[0096] D. Applications of image display devices Examples of such image display devices include liquid crystal displays and organic light-emitting diode (OLED) displays. Specific examples of image display devices include mobile phones (smartphones), laptop computers, and furniture. By shaping the edges of mobile phones and laptop computers to have three-dimensional curved surfaces, the screen size can be maximized. Furniture generally has three-dimensional curved surfaces, and by combining it with an image display device that also has a three-dimensional curved surface, an image display function can be obtained without compromising practicality. [Examples]

[0097] The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. The measurement methods for each characteristic are as follows.

[0098] (1) Measurement of phase difference The in-plane phase difference of the first and second phase difference films used in the examples and comparative examples was automatically measured using a KOBRA-WPR manufactured by Oji Instruments Co., Ltd. The measurement wavelength was 550 nm and the measurement temperature was 25 °C.

[0099] (2) Test of attachment of optical laminates to three-dimensional curved surfaces The test samples obtained in the examples and comparative examples were placed on a reflector, and the ratio of the bonded area to the three-dimensional curved surface was calculated using the image processing software ImageJ. The results are shown in Tables 1 to 3.

[0100] <Preparation of optically transparent adhesive film> <Preparation Example 1> (Preparation of acrylic oligomers) First, in a reaction vessel equipped with a stirrer, thermometer, reflux condenser, and nitrogen gas inlet tube, a mixture containing 60 parts by mass of dicyclopentanyl methacrylate (DCPMA), 40 parts by mass of methyl methacrylate (MMA), 3.5 parts by mass of α-thioglycerol as a chain transfer agent, and 100 parts by mass of toluene as a polymerization solvent was stirred at 70°C for 1 hour under a nitrogen atmosphere. Next, 0.2 parts by mass of 2,2'-azobisisobutyronitrile (AIBN) as a thermal polymerization initiator was added to the mixture to prepare a reaction solution, which was reacted under a nitrogen atmosphere at 70°C for 2 hours, and then at 80°C for 2 hours (polymerization reaction). Next, the reaction solution was heated to 130°C to volatilize and remove toluene, chain transfer agent, and unreacted monomers. This yielded an acrylic oligomer (solid form). The weight-average molecular weight of this acrylic oligomer was 5100.

[0101] (Preparation of prepolymer composition) In a flask, a monomer mixture consisting of 71 parts by mass of n-butyl acrylate (BA), 13 parts by mass of N-vinyl-2-pyrrolidone (NVP), 3 parts by mass of acryloylmorpholine (ACMO), and 13 parts by mass of 4-hydroxybutyl acrylate (4HBA) was mixed with two types of first photopolymerization initiators (totaling 0.062 parts by mass). The mixture was then irradiated with ultraviolet light under a nitrogen atmosphere to polymerize a portion of the monomer components in the mixture and obtain a prepolymer composition. The inter-entanglement molecular weight of n-butyl acrylate (BA) was 15000. As the first photopolymerization initiators, 0.031 parts by mass of BASF's "Omnirad 184" (1-hydroxycyclohexyl-phenyl-ketone) and 0.031 parts by mass of BASF's "Omnirad 651" (2,2-dimethoxy-2-phenylacetophenone) were used. Ultraviolet irradiation was continued until the viscosity of the composition reached approximately 20 Pa·s. This viscosity was measured using a B-type viscometer under the conditions of rotor No. 5, rotor speed of 10 rpm, and temperature of 30°C. The resulting prepolymer composition is a partially polymerized product containing a photopolymerized product (photopolymerized polymer P1a) and monomer components that have not undergone polymerization (residual monomer).

[0102] (Preparation of adhesive composition) Next, 100 parts by mass of the prepolymer composition, 3 parts by mass of the above-mentioned acrylic oligomer, 0.6 parts by mass of urethane acrylate oligomer (UAO) (product name "UN-350", manufactured by Negami Kogyo Co., Ltd.) as a second photopolymerizable polyfunctional compound, 0.4 parts by mass of a second photopolymerization initiator, 0.5 parts by mass of an antioxidant (product name "Irganox 1010", manufactured by BASF), 0.2 parts by mass of a rust inhibitor (product name "BT-120", 1,2,3-benzotriazole, manufactured by Johoku Chemical Industry Co., Ltd.), and 0.3 parts by mass of a silane coupling agent (product name "KBM-403", manufactured by Shin-Etsu Chemical Co., Ltd.) were mixed to obtain an adhesive composition. The amount of the second photopolymerizable polyfunctional compound (crosslinking agent) per 100 parts by mass of monomer components was 0.55 parts by mass. As the second photopolymerization initiator, we used "Omnirad819" (bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide) manufactured by BASF.

[0103] (Preparation of the base adhesive sheet) Next, an adhesive composition was applied to the peel-treated surface of a first peel-treated liner (product name "Diafoil MRF", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation), which has a peel-treated surface on one side, to form a coating film. Next, the peel-treated surface of a second peel-treated liner (product name "Diafoil MRE", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation), which also has a peel-treated surface on one side, was bonded onto the coating film on the first peel-treated liner. Next, ultraviolet light was irradiated onto the coating film between the peel-treated liners from the side of the second peel-treated liner to photo-cur the coating film and form an adhesive layer with a thickness of 100 μm (ultraviolet irradiation step). For ultraviolet irradiation, a black light lamp (wavelength 320 nm to 400 nm, manufactured by Toshiba Corporation) was used as the light source, and the illuminance was set to 6.5 mW / cm². 2 The integrated irradiation light dose is 1500 mJ / cm². 2 In the ultraviolet irradiation step, a photopolymerization reaction proceeds in the coating film in a reaction system containing the aforementioned residual monomer, additional monomer, and a second photopolymerizable polyfunctional compound (crosslinking agent), forming a photopolymerizable polymer P1b having a crosslinked structure. Furthermore, since this photopolymerization reaction proceeds around the photopolymerizable polymer P1a, the photopolymerizable polymer P1b is formed around the photopolymerizable polymer P1a. The adhesive layer formed in this step contains such photopolymerizable polymers P1a and P1b as the base polymer P1. In this manner, a base adhesive sheet with double-sided peel-off liners (first peel-off liner / base adhesive sheet (thickness 100 μm) / second peel-off liner) was prepared.

[0104] (Preparation of post-addition component solution) A solution of added components was prepared by mixing 6.0 parts by mass of trimethylolpropane triacrylate (TMPTA) (product name "Viscote #295", manufactured by Osaka Organic Chemical Industry Co., Ltd.) as a first-order photopolymerizable polyfunctional compound, 1.2 parts by mass of ethoxylated bisphenol A diacrylate (BPAEODE) (product name "ABE-300", manufactured by Shin Nakamura Chemical Industry Co., Ltd.) as another first-order photopolymerizable polyfunctional compound, 0.3 parts by mass of a third-order photopolymerization initiator, 7.0 parts by mass of an ultraviolet absorber (product name "Tinosorb S", manufactured by BASF), and 90.7 parts by mass of ethyl acetate as a solvent (all components except the solvent in the solution are added later). "Omnirad 819" manufactured by BASF was used as the third-order photopolymerization initiator.

[0105] (Preparation of optical adhesive sheets) First, the second release liner was peeled off the base adhesive sheet with the release liner described above. Then, the post-addition component solution was applied to the exposed surface of the base adhesive sheet to a thickness of 20 μm (coating treatment). A bar coater RDS No. 10 manufactured by RDSPECIALTIES was used for coating. Next, it was dried in a drying oven at 110°C for 60 seconds. Through the coating and drying treatments, the post-addition components (first photopolymerizable polyfunctional compound, third photopolymerization initiator, ultraviolet absorber) were permeated into the base adhesive sheet, and the solvent was vaporized. The penetration of the post-addition components into the base adhesive sheet formed a photocurable optical adhesive sheet. Per 100 parts by mass of the above-mentioned prepolymer composition, the amount of TMPTA added was 6.0 parts by mass, the amount of BPAEODE added was 1.2 parts by mass, the amount of third photopolymerization initiator (Omnirad819) added was 0.3 parts by mass, and the amount of ultraviolet absorber (Tinosorb S) added was 7.0 parts by mass. Next, the peel-treated side of a third peel-off liner (product name "Diafoil MRE", thickness 75 μm, manufactured by Mitsubishi Chemical Corporation), which has a peel-treated surface on one side, was attached to the adhesive sheet on the first peel-off liner.

[0106] As described above, an adhesive sheet with a release liner (first release liner / adhesive sheet (thickness 100 μm) / third release liner) was prepared. The adhesive sheet is a photocurable optical adhesive sheet containing a base polymer, a first photopolymerizable polyfunctional compound (TMPTA, BPAEODE), and a third photopolymerization initiator. This optical adhesive sheet was used as an optically transparent adhesive film.

[0107] <Example 1> <<Preparation of Polarizers>> As a thermoplastic resin substrate, an amorphous isophthalic copolymer polyethylene terephthalate film (thickness: 100 μm) in a long length with a Tg of approximately 75°C was used, and one side of the film was subjected to corona treatment. A PVA aqueous solution (coating solution) was prepared by dissolving 100 parts by mass of a PVA-based resin, which was prepared by mixing polyvinyl alcohol (degree of polymerization 4200, degree of saponification 99.2 mol%) and acetoacetyl-modified PVA (manufactured by Nippon Synthetic Chemical Industry Co., Ltd., trade name "Gosephymer") in a 9:1 ratio, with 13 parts by mass of potassium iodide. A 13 μm thick PVA-based resin layer was formed on the thermoplastic resin substrate by applying the above PVA aqueous solution to the corona-treated surface of the thermoplastic resin substrate and drying it at 60°C. The resulting laminate was uniaxially stretched 2.4 times in the longitudinal direction (longitudinal direction) in an oven at 130°C (air-assisted stretching). Next, the laminate was immersed for 30 seconds in an insolubilization bath at a liquid temperature of 40°C (a boric acid aqueous solution obtained by mixing 4 parts by mass of boric acid with 100 parts by mass of water) (insolubilization treatment). Next, the laminate was immersed for 60 seconds in a staining bath at a liquid temperature of 30°C (an iodine aqueous solution obtained by mixing iodine and potassium iodide in a mass ratio of 1:7 with 100 parts by mass of water) while adjusting the concentration so that the final transmittance (Ts) of the polarizer obtained would be the desired value (staining treatment). Next, the laminate was immersed for 30 seconds in a crosslinking bath at a liquid temperature of 40°C (a boric acid aqueous solution obtained by mixing 3 parts by mass of potassium iodide and 5 parts by mass of boric acid with 100 parts by mass of water) (crosslinking treatment). Subsequently, the laminate was immersed in a boric acid aqueous solution (boric acid concentration 4% by mass, potassium iodide concentration 5% by mass) at a liquid temperature of 70°C, and uniaxially stretched in the longitudinal direction (longitudinal direction) between rolls with different peripheral speeds to achieve a total stretch ratio of 5.5 times (underwater stretching treatment). Subsequently, the laminate was immersed in a washing bath at a liquid temperature of 20°C (an aqueous solution obtained by mixing 4 parts by mass of potassium iodide with 100 parts by mass of water) (washing treatment). Subsequently, the laminate was dried in an oven maintained at approximately 90°C while being brought into contact with a SUS (stainless steel) heated roll whose surface temperature was maintained at approximately 75°C (drying shrinkage treatment). In this manner, a polarizer was formed on a thermoplastic resin substrate. The thickness d3 of the polarizer was approximately 5.0 μm.

[0108] <<Attachment of the first phase difference film to the polarizer>> A first phase difference film (ZD12, manufactured by Zeon Corporation) having a single-layer structure of a stretched film containing COP was prepared. The first phase difference film had a refractive index of nx>ny>nz. The in-plane phase difference Re(550) of the first phase difference film was 99 nm. The thickness d5 of the first phase difference film was 25 μm. Next, the polarizer and the first phase difference film were bonded together using an ultraviolet-curing adhesive. Then, the ultraviolet-curing adhesive was irradiated with ultraviolet light to cure it, forming a UV adhesive layer containing the cured adhesive material. The thickness of the UV adhesive layer was 1 μm.

[0109] <<Applying a protective layer to the polarizer>> Next, the thermoplastic resin substrate was peeled off and removed from the polarizer. Subsequently, a TAC film (manufactured by Fujifilm Corporation, product name: TJ25UL, Re(550):0nm) was applied as a protective layer to the surface of the polarizer opposite to the first phase difference film. The thickness d7 of the protective layer was 25 μm. Subsequently, the UV-curable adhesive was irradiated with ultraviolet light to cure it, forming a UV adhesive layer containing the cured product of the UV-curable adhesive. The thickness of the UV adhesive layer was 1 μm. This allowed us to prepare a polarizing plate having a laminated structure of a first phase difference film / UV adhesive layer / polarizer / UV adhesive layer / protective layer. In the polarizing plate, the angle between the absorption axis direction of the polarizer and the slow phase axis direction of the first phase difference film was 45°.

[0110] <<Preparation of the second phase difference film>> A liquid crystal composition (coating solution) was prepared by dissolving 10 parts by mass of a polymerizable liquid crystal exhibiting a nematic liquid crystal phase (BASF: trade name "Paliocolor LC242", represented by the following formula) and 3 parts by mass of a photopolymerization initiator for the polymerizable liquid crystal compound (BASF: trade name "Irgacure 907") in 40 parts by mass of toluene. [ka] The surface of a polyethylene terephthalate (PET) film (38 μm thick) used as a coating substrate was rubbed with a rubbing cloth and subjected to orientation treatment. The direction of the orientation treatment was set so that when bonded to a polarizer (described later), it was at a 15° angle from the viewing side with respect to the absorption axis of the polarizer. The liquid crystal coating solution was applied to this orientation-treated surface using a bar coater, and the liquid crystal compound was oriented by heating and drying at 90°C for 2 minutes. In the liquid crystal layer formed in this manner, a metal halide lamp is used to apply 1 mJ / cm³ of liquid crystal. 2 A first liquid crystal alignment solidification layer was formed on the PET film by irradiating it with light and curing the liquid crystal layer. The thickness of the first liquid crystal alignment solidification layer was 2 μm. The first liquid crystal alignment solidification layer had a refractive index of nx > ny = nz. The in-plane phase difference Re(550) of the first liquid crystal alignment solidification layer was 270 nm. In other words, the first liquid crystal alignment solidification layer can function as a λ / 2 plate.

[0111] Furthermore, a second liquid crystal alignment solidification layer (λ / 4 plate) was formed on the PET film in the same manner as described above, except that the orientation processing direction was changed to a 75° direction relative to the absorption axis axis of the polarizer when viewed from the viewing side. The in-plane phase difference Re(550) of the second liquid crystal alignment solidification layer was 140 nm. In other words, the second liquid crystal alignment solidification layer can function as a λ / 4 plate.

[0112] Next, the first liquid crystal alignment solidified layer and the second liquid crystal alignment solidified layer were bonded together using an ultraviolet-curing adhesive. Then, the ultraviolet-curing adhesive was cured by irradiating it with ultraviolet light. This formed a UV adhesive layer containing the cured product of the ultraviolet-curing adhesive. The thickness of the UV adhesive layer was 1 μm. Next, the PET film (coated substrate) was peeled off from the first liquid crystal alignment solidification layer. This allowed for the preparation of a second phase difference film having a laminated structure of a first liquid crystal alignment solidification layer (λ / 2 layer) / UV adhesive layer / second liquid crystal alignment solidification layer (λ / 4 layer) on a PET film (coated substrate). The thickness d6 of the second phase difference film was 4 μm.

[0113] <<Attachment of the second phase difference film to the polarizing plate>> Next, the protective layer of the polarizing plate and the first liquid crystal alignment solidification layer of the second phase difference film were bonded together using an ultraviolet-curing adhesive. Subsequently, the ultraviolet-curing adhesive was irradiated with ultraviolet light to cure it, forming a UV adhesive layer containing the cured product of the ultraviolet-curing adhesive. The thickness of the UV adhesive layer was 1 μm. Subsequently, the PET film (coated substrate) was peeled off from the second liquid crystal alignment solidification layer. This allowed us to prepare an intermediate laminate having a laminated structure of a first phase difference film / UV adhesive layer / polarizer / UV adhesive layer / protective layer / UV adhesive layer / second phase difference film. In the intermediate laminate, the angle between the polarizer's absorption axis and the slow axis of the first liquid crystal alignment solidification layer was 15°, and the angle between the polarizer's absorption axis and the slow axis of the second liquid crystal alignment solidification layer was 75°.

[0114] <<Formation of the first adhesive layer>> Next, the optically transparent adhesive film obtained in Preparation Example 1 was attached to the surface of the first phase difference film opposite to the polarizer to form the first adhesive layer. The thickness d1 of the first adhesive layer was 300 μm.

[0115] <<Formation of the second adhesive layer>> Furthermore, a (meth)acrylic adhesive was applied to the surface of the second phase difference film opposite to the polarizer to form a second adhesive layer. The thickness d2 of the second adhesive layer was 5 μm.

[0116] Based on the above, an optical laminate having a laminated structure of a first adhesive layer / first phase difference film / UV adhesive layer / polarizer / UV adhesive layer / protective layer / UV adhesive layer / second phase difference film / second adhesive layer was prepared.

[0117] <<Preparation of Test Samples>> Next, an acrylic resin film (manufactured by Nitto Denko Corporation, product name: CAT film) was attached to the surface of the second adhesive layer opposite the second phase difference film, as a substitute for the image display panel. The thickness d4 of the acrylic resin film was 40 μm. Next, the optical laminate was attached to a cover glass (transparent member) having a three-dimensional curved surface using a first adhesive layer. The three-dimensional curved surface was concave, and its radius of curvature was 38.6 mm. More specifically, after setting the cover glass in a curved lens bonding device (Asano Research Institute Co., Ltd., TFH-0321-UD), the optical laminate with the acrylic resin film attached was positioned so that the first adhesive layer faced the three-dimensional curved surface of the cover glass with a gap between them. Next, a mold having a convex surface corresponding to the three-dimensional curved surface of the cover glass was brought into contact with the optical laminate from the side opposite the cover glass, and the cover glass was moved toward the optical laminate. The temperature of the mold was 95°C. This brought the first adhesive layer of the optical laminate into contact with the three-dimensional curved surface of the cover glass. Based on the above, a test sample was obtained comprising a transparent member having a three-dimensional curved surface, an optical laminate, and a substitute for an image display panel. The values ​​of formula (1) in this test sample are shown in Table 1.

[0118] <Example 2> A test sample was obtained in the same manner as in Example 1, except that the thickness d1 of the first adhesive layer was changed to 200 μm and the thickness d2 of the second adhesive layer was changed to 25 μm. The values ​​of formula (1) above for this test sample are shown in Table 1.

[0119] <Example 3> A test sample was obtained in the same manner as in Example 1, except that the thickness d2 of the second adhesive layer was changed to 25 μm. The values ​​of formula (1) in the test sample are shown in Table 1.

[0120] <Example 4> A test sample was obtained in the same manner as in Example 1, except that the thickness d1 of the first adhesive layer was changed to 200 μm and the radius of curvature of the three-dimensional curved surface of the cover glass was changed to 51.5 mm. The values ​​of formula (1) above for this test sample are shown in Table 1.

[0121] <Example 5> A test sample was obtained in the same manner as in Example 4, except that the thickness d1 of the first adhesive layer was changed to 300 μm. The values ​​of formula (1) in the test sample are shown in Table 1.

[0122] <Example 6> A test sample was obtained in the same manner as in Example 4, except that the thickness d1 of the first adhesive layer was changed to 100 μm and the thickness d2 of the second adhesive layer was changed to 25 μm. The values ​​of formula (1) above for this test sample are shown in Table 1.

[0123] <Example 7> A test sample was obtained in the same manner as in Example 4, except that the thickness d2 of the second adhesive layer was changed to 25 μm. The values ​​of formula (1) in the test sample are shown in Table 1.

[0124] <Example 8> A test sample was obtained in the same manner as in Example 4, except that the thickness d1 of the first adhesive layer was changed to 300 μm and the thickness d2 of the second adhesive layer was changed to 25 μm. The values ​​of formula (1) above for this test sample are shown in Table 1.

[0125] <Example 9> A test sample was obtained in the same manner as in Example 1, except that the thickness d1 of the first adhesive layer was changed to 100 μm and the radius of curvature of the three-dimensional curved surface of the cover glass was changed to 77.2 mm. The values ​​of formula (1) above for this test sample are shown in Table 2.

[0126] <Example 10> A test sample was obtained in the same manner as in Example 9, except that the thickness d1 of the first adhesive layer was changed to 200 μm. The values ​​of formula (1) in the test sample are shown in Table 2.

[0127] <Example 11> A test sample was obtained in the same manner as in Example 9, except that the thickness d1 of the first adhesive layer was changed to 300 μm. The values ​​of formula (1) in the test sample are shown in Table 2.

[0128] <Example 12> A test sample was obtained in the same manner as in Example 9, except that the thickness d2 of the second adhesive layer was changed to 25 μm. The values ​​of formula (1) in the test sample are shown in Table 2.

[0129] <Example 13> A test sample was obtained in the same manner as in Example 9, except that the thickness d1 of the first adhesive layer was changed to 200 μm and the thickness d2 of the second adhesive layer was changed to 25 μm. The values ​​of formula (1) in the test sample are shown in Table 2.

[0130] <Example 14> A test sample was obtained in the same manner as in Example 9, except that the thickness d1 of the first adhesive layer was changed to 300 μm and the thickness d2 of the second adhesive layer was changed to 25 μm. The values ​​of formula (1) above for this test sample are shown in Table 2.

[0131] <Comparative Example 1> A test sample was obtained in the same manner as in Example 1, except that the thickness d1 of the first adhesive layer was changed to 100 μm. The values ​​of formula (1) in the test sample are shown in Table 3.

[0132] <Comparative Example 2> A test sample was obtained in the same manner as in Example 1, except that the thickness d1 of the first adhesive layer was changed to 200 μm. The values ​​of formula (1) in the test sample are shown in Table 3.

[0133] <Comparative Example 3> A test sample was obtained in the same manner as in Example 1, except that the thickness d1 of the first adhesive layer was changed to 100 μm and the thickness d2 of the second adhesive layer was changed to 25 μm. The values ​​of formula (1) above for this test sample are shown in Table 3.

[0134] <Comparative Example 4> A test sample was obtained in the same manner as in Example 4, except that the thickness d1 of the first adhesive layer was changed to 100 μm. The values ​​of formula (1) in the test sample are shown in Table 3.

[0135] [Table 1]

[0136] [Table 2]

[0137] [Table 3]

[0138] [evaluation] As is clear from Tables 1 to 3, when the test sample satisfies equation (1) described above, the adhesion ratio of the optical laminate to a three-dimensional curved surface can be significantly improved. [Industrial applicability]

[0139] The image display device manufactured according to the embodiments of the present invention can be used in various industrial products, and is particularly suitable for use in mobile phones (smartphones), laptop computers, furniture, and the like. [Explanation of Symbols]

[0140] 1 Optical laminate 11 First adhesive layer 12 Second adhesive layer 13 Polarizer 14. First Phase Difference Film 15. Second phase difference film 16 Protective layer 2 Transparent component 21 Three-dimensional curved surface 3 Image display panel 100 Image Display Devices

Claims

1. A transparent member having a three-dimensional curved surface, The optical laminate attached to the three-dimensional curved surface, The optical laminate comprises an image display panel located on the opposite side of the three-dimensional curved surface from the optical laminate, The optical laminate, The first adhesive layer in contact with the three-dimensional curved surface, A polarizer located on the opposite side of the three-dimensional curved surface from the first adhesive layer, The polarizer comprises a second adhesive layer located on the opposite side from the first adhesive layer, and in contact with the image display panel, An image display device that satisfies the following equation (1): R ２ ×(d1+d2) / 1000>310・・・(1) (In equation (1), R represents the radius of curvature of the three-dimensional curved surface [mm], d1 represents the thickness of the first adhesive layer [μm], and d2 represents the thickness of the second adhesive layer [μm]).

2. The image display device according to claim 1, wherein the sum of the thickness d1 of the first adhesive layer and the thickness d2 of the second adhesive layer is greater than 150 μm and less than 500 μm.

3. The image display device according to claim 1, wherein the thickness d1 of the first adhesive layer is greater than 250 μm and less than 500 μm.

4. The image display device according to claim 1, wherein the thickness d2 of the second adhesive layer is 10 μm or more and less than 50 μm.

5. The image display device according to claim 1, wherein the thickness d1 of the first adhesive layer exceeds the sum of the thickness d2 of the second adhesive layer, the thickness d3 of the polarizer, and the thickness d4 of the image display panel.

6. The image display device according to claim 1, wherein the thickness d1 of the first adhesive layer exceeds the sum of the thickness d2 of the second adhesive layer and the thickness d3 of the polarizer.

7. The image display panel is curved along the three-dimensional curved surface, The image display device according to claim 1, wherein the radius of curvature of the image display panel is smaller than the radius of curvature of the three-dimensional curved surface.

8. The image display device according to claim 7, wherein the radius of curvature of the image display panel is greater than 2 mm and less than 100 mm.

9. The image display device according to claim 7, wherein the radius of curvature of the image display panel is greater than 2 mm and less than 65 mm.

10. The image display device according to claim 7, wherein the radius of curvature of the image display panel is greater than 2 mm and less than 45 mm.

11. The optical laminate further comprises a first phase difference film located between the polarizer and the first adhesive layer. The image display device according to claim 1, wherein the radius of curvature of the first phase difference film is greater than the radius of curvature of the polarizer.

12. The image display device according to claim 11, wherein the first phase difference film functions as a λ / 4 plate.

13. The optical laminate further comprises a second phase difference film located between the second adhesive layer and the polarizer. The image display device according to claim 1, wherein the radius of curvature of the second phase difference film is smaller than the radius of curvature of the polarizer.

14. A step of preparing an optical laminate comprising a polarizer and a second adhesive layer in this order, The optical laminate is attached to the image display panel by the second adhesive layer, The process includes, in this order, the step of attaching the optical laminate to the three-dimensional curved surface of the transparent member using a first adhesive layer, A method for manufacturing an image display device that satisfies the following formula (1): 2500>R ２ ×(d1+d2) / 1000>310・・・(1) (In equation (1), R represents the radius of curvature of the three-dimensional curved surface [mm], d1 represents the thickness of the first adhesive layer [μm], and d2 represents the thickness of the second adhesive layer [μm]).

15. A step of preparing an optical laminate comprising a polarizer and a second adhesive layer in this order, The optical laminate is attached to the image display panel by the second adhesive layer, The optical laminate is attached to the transparent member by a first adhesive layer, The process includes, in this order, the step of forming the transparent member into a three-dimensional curved surface while the image display panel and the optical laminate are attached to the transparent member, A method for manufacturing an image display device that satisfies the following formula (1): 2500>R ２ ×(d1+d2) / 1000>310・・・(1) (In equation (1), R represents the radius of curvature of the three-dimensional curved surface [mm], d1 represents the thickness of the first adhesive layer [μm], and d2 represents the thickness of the second adhesive layer [μm]).

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