Image display device and method for manufacturing image display device

Abstract

An image display device and a method for manufacturing the image display device are provided, which improve the tracking accuracy of an optical laminate relative to a three-dimensional curved surface. The image display device according to an embodiment of the present invention includes 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 three-dimensional curved surface relative to the optical laminate. The optical laminate includes 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 formula (1), R represents the radius of curvature of the three-dimensional 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] This invention relates to an image display device and a method for manufacturing an image display device. Background Technology

[0002] Previously, image display devices, represented by liquid crystal display devices and electroluminescent (EL) display devices (e.g., organic EL display devices and inorganic EL display devices), have become rapidly popular. In order to impart the desired optical characteristics to such image display devices, it is known to use optical laminates having a retardation film and a polarizer (e.g., see Patent Document 1).

[0003] Existing technical documents Patent documents Patent Document 1: Japanese Patent Application Publication No. 2024-124169 Summary of the Invention

[0004] The problem that the invention aims to solve In recent years, the applications of image display devices have been expanding. Along with this, the shapes of image display devices have become more diverse, and sometimes image display devices have non-developable three-dimensional curved surfaces. This study investigated the fabrication of image display devices with three-dimensional curved surfaces by attaching optical laminates to such devices, or by attaching optical laminates to image display devices and then forming the three-dimensional curved surface.

[0005] However, it is difficult to use the optical laminate as described in Patent Document 1 to form a three-dimensional surface, and it is possible that the optical laminate cannot fully follow the three-dimensional surface in an image display device.

[0006] The main objective of this invention is to provide an image display device and a method for manufacturing the image display device that can improve the following performance of optical laminates relative to three-dimensional curved surfaces.

[0007] Methods for solving problems [1] An image display device according to an embodiment of the present invention includes 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 three-dimensional curved surface relative to the optical laminate. The optical laminate includes 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 three-dimensional curved surface relative to the first adhesive layer. The second adhesive layer is located on the opposite side of the first adhesive layer relative to the polarizer. The second adhesive layer is in contact with the image display panel. The image display device satisfies the following formula (1).

[0008] R 2 ×(d1+d2) / 1000>310···(1) (In equation (1), R represents the radius of curvature of the three-dimensional surface [mm], d1 represents the thickness of the first adhesive layer [μm], and d2 represents the thickness of the second adhesive layer [μm].) [2] According to 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.

[0009] [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.

[0010] [4] In the image display device according to any one of [1] to [3] above, the thickness d2 of the second adhesive layer may be 10 μm or more and less than 50 μm.

[0011] [5] In the image display device according to any one of [1] to [4] above, the thickness d1 of the first adhesive layer may also 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.

[0012] [6] In the image display device according to any one of [1] to [5] above, the thickness d1 of the first adhesive layer may also exceed the sum of the thickness d2 of the second adhesive layer and the thickness d3 of the polarizer.

[0013] [7] In the image display device according to any one of [1] to [6] above, the image display panel may also be curved along the three-dimensional surface. The radius of curvature of the image display panel may also be smaller than the radius of curvature of the three-dimensional surface.

[0014] [8] According to 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.

[0015] [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.

[0016]

[10] The image display device according to any one of [7] to [9] above, wherein the radius of curvature of the image display panel may be greater than 2 mm and less than 45 mm.

[0017]

[11] In the image display device according to any one of [1] to

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

[0018]

[12] In the image display device described in

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

[0019]

[13] The image display device according to any one of [1] to

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

[0020]

[14] Another aspect of the manufacturing method of the image display device of the present invention includes, in sequence, a step of preparing an optical laminate having a polarizer and a second adhesive layer in sequence; a step of attaching the optical laminate to an image display panel through the second adhesive layer; and a step of attaching the optical laminate to a three-dimensional curved surface of a transparent member through a first adhesive layer. In this manufacturing method of the image display device, the following formula (1) is satisfied.

[0021] 2500>R 2 ×(d1+d2) / 1000>310···(1) (In formula (1), R represents the radius of curvature of the three-dimensional surface [mm], d1 represents the thickness of the first adhesive layer [μm], and d2 represents the thickness of the second adhesive layer [μm]).

[0022]

[15] A method for manufacturing an image display device according to another aspect of the present invention comprises, in sequence, a step of preparing an optical laminate having a polarizer and a second adhesive layer in sequence; a step of attaching the optical laminate to an image display panel through the second adhesive layer; a step of attaching the optical laminate to a transparent member through a first adhesive layer; and a step of molding the transparent member into a three-dimensional curved surface with the image display panel and the optical laminate attached to the transparent member. In this method for manufacturing an image display device, the following formula (1) is satisfied.

[0023] 2500>R 2 ×(d1+d2) / 1000>310···(1) (In formula (1), R represents the radius of curvature of the three-dimensional surface [mm], d1 represents the thickness of the first adhesive layer [μm], and d2 represents the thickness of the second adhesive layer [μm]).

[0024] Invention Effects According to embodiments of the present invention, the following ability of optical laminates relative to three-dimensional curved surfaces can be improved. Attached Figure Description

[0025] Figure 1 This is a schematic configuration diagram of an image display device according to one embodiment of the present invention.

[0026] Figure 2 yes Figure 1 A schematic cross-sectional view of the optical laminate of an image display device.

[0027] Figure 3 yes Figure 2 A schematic cross-sectional view of the second phase difference film in the optical laminate.

[0028] Figure 4 This is a schematic cross-sectional view of an optical laminate included in an image display device according to another embodiment of the present invention.

[0029] Explanation of symbols 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 layers 2 Transparent components 21 Three-dimensional surfaces 3 Image display panel 100 Image display devices Detailed Implementation

[0030] Hereinafter, representative embodiments of the present invention will be described, but the present invention is not limited to these embodiments. In addition, in order to make the description clearer, the width, thickness, shape, etc. of each part are sometimes schematically shown in the accompanying drawings compared with the embodiments, but these are just examples and do not limit the interpretation of the present invention.

[0031] (Definitions of terms and symbols) The definitions of terms and symbols used in this specification are as follows.

[0032] (1) Refractive index (nx, ny, nz) “nx” is the refractive index in the direction where the refractive index in the plane becomes the largest (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.

[0033] (2) In-plane phase difference (Re) “Re(λ)” is the in-plane phase difference measured at 23°C using light with a wavelength of λ nm. For example, “Re(550)” is the in-plane phase difference measured at 23°C using light with a wavelength of 550 nm. When the thickness of the layer (film) is set to d (nm), Re(λ) is obtained by the formula: Re(λ) = (nx - ny) × d.

[0034] (3) Phase difference in the thickness direction (Rth) “Rth(λ)” is the phase difference in the thickness direction measured by light with a wavelength of λ nm at 23°C. For example, “Rth(550)” is the phase difference in the thickness direction measured by light with a wavelength of 550 nm at 23°C. When the thickness of the layer (film) is set to d (nm), Rth(λ) is obtained by the formula: Rth(λ) = (nx - nz) × d.

[0035] (4) Nz coefficient The Nz coefficient is obtained by Nz=Rth / Re.

[0036] (5) Angle When referring to angles in this specification, the angle includes both clockwise and counterclockwise relative to a reference direction. Therefore, for example, "45°" means ±45°.

[0037] A. Overview of Image Display Devices Figure 1 This is a schematic configuration diagram of an image display device according to one embodiment of the present invention. Figure 2 yes Figure 1 A schematic cross-sectional view of the optical laminate of an image display device.

[0038] like Figure 1 and Figure 2 As shown, in one embodiment, the image display device 100 includes 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 three-dimensional curved surface 21 relative to the optical laminate 1.

[0039] The optical laminate 1 sequentially comprises a first adhesive layer 11, a polarizer 13, and a second adhesive layer 12. 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 relative to the first adhesive layer 11. The second adhesive layer 12 is located on the opposite side of the first adhesive layer 11 relative to the polarizer 13. The second adhesive layer 12 is in contact with the image display panel 3.

[0040] The image display device 100 satisfies the following formula (1).

[0041] R 2 ×(d1+d2) / 1000>310···(1) (In equation (1), R represents the radius of curvature of the three-dimensional 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 investigated the application of optical laminates to image display devices with three-dimensional curved surfaces and found that the thickness of the adhesive layer in the optical laminate affects the following of the optical laminate relative to the three-dimensional curved surface.

[0042] Therefore, the inventors conducted an in-depth study on the thickness of the adhesive layer of the optical laminate and found that if the radius of curvature of the three-dimensional surface and the thickness of the adhesive layer satisfy a specific relationship, the following performance of the optical laminate relative to the three-dimensional surface can be improved. More specifically, if the image display device satisfies the above formula (1), the optical laminate can be stably shaped into a three-dimensional surface (specifically, the optical laminate is attached to a three-dimensional surface or attached to a transparent component and then shaped into a three-dimensional surface), allowing the optical laminate to fully follow the three-dimensional surface.

[0043] 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).

[0044] 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 surface [mm], d1 represents the thickness of the first adhesive layer [μm], and d2 represents the thickness of the second adhesive layer [μm].) Based on this configuration, the following ability of the optical laminate to follow the three-dimensional surface can be further improved, and the optical laminate can be more stably shaped into a three-dimensional surface.

[0045] The radius of curvature R of the three-dimensional curved surface 21 of the transparent component 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, as long as the image display device satisfies the above formula (1), the optical laminate can be formed along the three-dimensional curved surface.

[0046] 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, and also, for example, 10 mm or more, and also, for example, 20 mm or more.

[0047] It should be noted that the radius of curvature of a three-dimensional surface can be measured using methods such as laser interferometers, laser displacement meters, spectrometers, and SEM.

[0048] 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 more than 150 μm, and even more preferably 200 μm or more.

[0049] 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 less than 400 μm, and even more preferably less than 350 μm.

[0050] If the total thickness of the first adhesive layer and the second adhesive layer is within such a range, the image display device can stably satisfy the above formula (1).

[0051] 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 more than 250 μm, and most preferably 280 μm or more.

[0052] 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 less than 400 μm.

[0053] If the first adhesive layer has such a thickness, the optical laminate can be stably attached to a three-dimensional curved surface.

[0054] The thickness d2 of the second adhesive layer 12 is, for example, 5 μm or more, preferably 10 μm or more, more preferably more than 15 μm, further preferably 20 μm or more, and especially preferably 25 μm or more.

[0055] 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 less than 40 μm.

[0056] If the second adhesive layer has such a thickness, the optical laminate can be more stably attached to the three-dimensional curved surface.

[0057] 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 the sum of the thickness d2 of the second adhesive layer 12 and the thickness d3 of the polarizer 13.

[0058] 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. This configuration improves the operability of the first adhesive layer and enhances the durability of the optical laminate.

[0059] 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, relative to the sum of the thickness d2 of the second adhesive layer 12 and the thickness d3 of the polarizer 13.

[0060] 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 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.

[0061] 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. This configuration further improves the operability of the first adhesive layer and stably enhances the durability of the optical laminate.

[0062] 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, relative 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.

[0063] 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.

[0064] If the polarizer has such a thickness, it is possible to achieve thinner optical laminates, which in turn allows for the miniaturization of image display devices.

[0065] 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. If the image display panel has such a thickness, miniaturization of the image display device can be steadily achieved.

[0066] like Figure 2As shown, 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 example shown, the first retardation film 14 is in contact with the first adhesive layer 11.

[0067] The first phase difference film 14 can typically function as a protective layer for the polarizer 13.

[0068] The first phase retardation film 14 can have an in-plane phase retardation or a phase retardation in the thickness direction. The first phase retardation film 14 can function as a λ / 4 plate, or as a λ / 2 plate, λ / 5 plate, λ / 6 plate, or C-Plate.

[0069] In one embodiment, the first phase difference film 14 has an in-plane phase difference.

[0070] The refractive index of the first phase retardation film 14 exhibits, for example, a relationship of nx > ny ≥ nz, preferably a relationship of nx > ny > nz. It should be noted 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, without impairing the effects of the invention, it may sometimes be expressed as ny > nz or ny <nz。

[0071] In the example shown, the first phase difference film 14 functions as a λ / 4 plate. With this configuration, in an image display device, it is possible to improve visual confirmability through an optical component with polarizing effect (hereinafter, sometimes referred to as a polarizing component).

[0072] The in-plane phase difference Re(550) of the first phase retardation film 14 is, for example, 80 nm or more, or 90 nm or more. On the other hand, the in-plane phase difference Re(550) of the first phase retardation film 14 is, for example, 160 nm or less, preferably 145 nm or less, more preferably 130 nm or less, even more preferably 120 nm or less, and especially preferably 110 nm or less.

[0073] If the first phase difference film has such a Re (550), then in the image display device, the visual confirmability through the polarizing member can be stably improved, and the desired coloring can be stably displayed.

[0074] The phase difference Rth (550) in the thickness direction of the first phase difference film 14 is, for example, 80 nm to 200 nm, preferably 90 nm to 160 nm.

[0075] The Nz coefficient of the first phase difference film 14 is, for example, 0.5 to 5.0, preferably 1.0 to 3.0.

[0076] The first phase difference film 14 with in-plane phase difference can exhibit inverse wavelength dispersion characteristics where in-plane birefringence increases in proportion to the wavelength of the measurement light, positive wavelength dispersion characteristics where in-plane birefringence decreases in proportion to the wavelength of the measurement light, or flat wavelength dispersion characteristics where in-plane birefringence hardly changes according to the wavelength of the measurement light.

[0077] 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.

[0078] If the thickness of the first phase difference film is above such a lower limit, then the first phase difference film can stably function as a protective layer for the polarizer.

[0079] 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.

[0080] If the thickness of the first phase difference film is below such an upper limit, then the thinning of the optical laminate can be pursued.

[0081] The angle between the slow 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°.

[0082] With this configuration, visual confirmation via the polarizing element can be improved more stably in image display devices.

[0083] The first phase retardation film 14 is typically attached to the polarizer 13 via an adhesive layer 17. Hereinafter, the adhesive layer that holds the first phase retardation film 14 to the polarizer 13 will sometimes be referred to as the first adhesive layer 17a.

[0084] The first adhesive layer 17a can be an adhesive layer or a bonding agent layer.

[0085] In one embodiment, the first adhesive layer 17a is an adhesive layer. In other words, the first adhesive layer 17a comprises a cured product of any suitable adhesive.

[0086] Examples of adhesives include water-based adhesives; thermosetting adhesives; moisture-curing adhesives; and ultraviolet-curing adhesives (UV adhesives), among other active energy ray-curing adhesives. Active energy ray-curing adhesives are preferred.

[0087] Adhesives can be used alone or in combination.

[0088] 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.

[0089] In one embodiment, the optical laminate 1 further comprises a second retardation film 15.

[0090] The second retardation film 15 is located between the polarizer 13 and the second adhesive layer 12. In the example shown, the second retardation film 15 is in contact with the second adhesive layer 12.

[0091] The second phase retardation film 15 can have an in-plane phase retardation or a phase retardation in the thickness direction. The second phase retardation film 15 can function as a λ / 4 plate, or as a λ / 2 plate, λ / 3 plate, λ / 5 plate, or C-Plate.

[0092] In one embodiment, the second phase difference film 15 has an in-plane phase difference.

[0093] The refractive index of the second retardation film 15 may exhibit a relationship of nx > ny, and preferably a relationship of nx > nz ≥ ny. The second retardation film 15 may also be a combination of multiple retardation films. Multiple retardation films exhibiting a relationship of nx > ny may also be combined. Alternatively, retardation films exhibiting relationships of nx > ny and nx = ny may also be combined.

[0094] In the example shown, the second phase retardation film 15 functions as a λ / 4 plate. This configuration imparts excellent anti-reflective properties to the image display device.

[0095] The in-plane phase difference Re(550) of the second phase difference film 15 is, for example, 100nm to 300nm, preferably 100nm to 190nm, more preferably 110nm to 170nm, and even more preferably 130nm to 160nm.

[0096] The Nz coefficient of the second phase difference film 15 is, for example, 0.3 to 1.5, preferably 0.9 to 1.3.

[0097] The second phase difference film 15 with in-plane phase difference can exhibit inverse wavelength dispersion characteristics where in-plane birefringence increases in proportion to the wavelength of the measurement light, positive wavelength dispersion characteristics where in-plane birefringence decreases in proportion to the wavelength of the measurement light, or flat wavelength dispersion characteristics where in-plane birefringence hardly changes according to the wavelength of the measurement light.

[0098] The thickness d6 of the second retardation film 15 is, for example, 15 μm or less, preferably less than 10 μm, and more preferably less than 5 μm. On the other hand, the lower limit of the thickness d6 of the second retardation film 15 is typically 1 μm.

[0099] If the second phase retardation film has such a thickness, the optical laminate can be further thinned.

[0100] 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 example shown, the protective layer 16 is located between the polarizer 13 and the second retardation film 15.

[0101] With this configuration, the protective layer can stably protect the polarizer.

[0102] 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.

[0103] In the example shown, the protective layer 16 is attached to the polarizer 13 via the adhesive layer 17, and is also attached to the second retardation film 15 via the adhesive layer 17. Hereinafter, the adhesive layer that bonds the protective layer 16 to the polarizer 13 will sometimes be referred to as the second adhesive layer 17b, and the adhesive layer that bonds the protective layer 16 to the second retardation film 15 will sometimes be referred to as the third adhesive layer 17c.

[0104] The second adhesive layer 17b and the third adhesive layer 17c are each described in the same manner as the first adhesive layer 17a described above. Therefore, detailed descriptions of the second adhesive layer 17b and the third adhesive layer 17c are omitted.

[0105] The optical laminate 1 has any suitable shape when viewed from the lamination direction.

[0106] Examples of possible shapes for the optical laminate 1 as viewed from the stacking direction include polygonal shapes such as rectangles, circles, ellipses, and 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.

[0107] The dimensions of the optical laminate 1 are arbitrarily and appropriately adjusted.

[0108] B. Details of the image display device Next, refer to Figure 1 and Figure 2 The details of an optical laminate according to one embodiment will be described.

[0109] like Figure 1As shown, the image display device 100 includes the aforementioned transparent member 2, the aforementioned optical laminate 1, and the aforementioned image display panel 3.

[0110] B-1. Transparent component Transparent component 2 is typically capable of transmitting light with wavelengths from 410 nm to 650 nm.

[0111] The total light transmittance of the transparent component 2 at a wavelength of 590 nm is, for example, 80% to 99%, preferably 90% to 98%.

[0112] Transparent components 2 can include, for example, the front panel of a cover glass, a lens, or a patterned film.

[0113] A three-dimensional curved surface 21 with the aforementioned radius of curvature R is provided on the transparent component 2.

[0114] The three-dimensional surface 21 can be either a concave or a convex surface. In the example shown, the three-dimensional surface 21 is a concave surface, which is disposed on the surface of the image display panel 3 in the transparent member 2.

[0115] B-2. Optical laminate Optical laminate 1 is typically flexible.

[0116] The optical laminate 1 is attached to the three-dimensional curved surface 21 of the transparent member 2 via a first adhesive layer 11. Thus, at least a portion of the optical laminate 1 is bent along the three-dimensional curved surface 21, forming a three-dimensional curved surface. In the example shown, the entire optical laminate 1 is bent along the three-dimensional curved surface 21.

[0117] like Figure 2 As shown, in one embodiment, the optical laminate 1 sequentially comprises the first adhesive layer 11, the first retardation 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 retardation film 15, and the second adhesive layer 12.

[0118] With the optical laminate 1 attached to the three-dimensional curved surface 21, the first phase retardation film 14, the polarizer 13, the protective layer 16, and the second phase retardation film 15 are each bent along the three-dimensional curved surface 21 (see reference). Figure 1 ).

[0119] B-2-1. First Adhesive Layer The first adhesive layer 11 is typically located at one end of the lamination direction in 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.

[0120] The first adhesive layer 11 is typically capable of transmitting light with wavelengths from 410 nm to 650 nm.

[0121] The total light transmittance of the first adhesive layer 11 at a wavelength of 590 nm is, for example, 80% to 95%, and further, for example, 85% to 93%.

[0122] The first adhesive layer 11 is composed of any suitable adhesive (adhesive composition).

[0123] The adhesive composition typically has a base polymer.

[0124] Examples of basic polymers include (meth)acrylic polymers, silicone polymers, polyesters, polyurethanes, polyamides, polyvinyl ethers, vinyl acetate / vinyl chloride copolymers, modified polyolefins, epoxy polymers, fluoropolymers, natural rubber, and synthetic rubber. It should be noted that "(meth)acrylic polymers" refers to acrylic polymers and / or methacrylic polymers.

[0125] The base polymers can be used alone or in combination.

[0126] In one embodiment, the first adhesive layer 11 comprises an acrylic adhesive composition containing a (meth)acrylic polymer as the base polymer. This configuration improves the optical transparency of the first adhesive layer and stably imparts suitable adhesive properties such as wettability, cohesiveness, and tackiness to the first adhesive layer.

[0127] The proportion of the (meth)acrylic polymer in the solid component of the acrylic adhesive composition is, for example, 50% by mass or more, preferably 70% by mass or more, and more preferably 90% by mass or more.

[0128] (Meth)acrylic polymers preferably have a cross-linked structure. More specifically, (meth)acrylic polymers comprise (meth)acrylic polymer chains with a cross-linked structure.

[0129] (Meth)acrylic polymers contain building blocks derived from alkyl (meth)acrylates. Alkyl (meth)acrylates with alkyl groups having 1 to 20 carbon atoms are suitable as the alkyl group. Alkyl (meth)acrylates may have branched alkyl groups or cyclic alkyl groups.

[0130] The proportion of (meth)acrylate-derived constituent units relative to the total number of constituent units in the (meth)acrylate polymer chain is, for example, 50% by mass or more, preferably 55% by mass or more, and more preferably 60% by mass or more.

[0131] The proportion of (meth)acrylate alkyl ester-derived constituent units having 4 to 10 carbon atoms relative to the total number of constituent units in the (meth)acrylate polymer chain is, for example, 40% by mass or more, preferably 50% by mass or more, and more preferably 55% by mass or more. If the proportion of (meth)acrylate alkyl ester-derived constituent units is within this range, the glass transition temperature (Tg) of the polymer chain can be suitably adjusted.

[0132] It should be noted that the total number of constituent units of a (meth)acrylic polymer chain refers to the components other than the monomers used to form cross-linking structures (such as polyfunctional (meth)acrylates, urethane (meth)acrylates, etc., as described later) and cross-linking agents, from all the monomer components that make up the polymer.

[0133] (Meth)acrylic polymers may also further include constituent units derived from comonomers, depending on the intended use.

[0134] Specific examples of comonomers include vinyl monomers such as hydroxyl-containing monomers, carboxyl-containing monomers, nitrogen-containing monomers, anhydride-containing monomers, caprolactone adducts of (meth)acrylic acid, sulfonic acid-containing monomers, phosphate-containing monomers, vinyl acetate, vinyl propionate, styrene, and α-methylstyrene; cyanoacrylate monomers such as acrylonitrile and methacrylonitrile; epoxy-containing monomers such as glycidyl methacrylate; diol acrylate monomers such as polyethylene glycol (meth)acrylic acid, polypropylene glycol (meth)acrylic acid, methoxyethylene glycol (meth)acrylic acid, and methoxypolypropylene glycol (meth)acrylic acid); and acrylate monomers such as tetrahydrofurfuryl methacrylate, fluoro(meth)acrylic acid, organosilicon (meth)acrylic acid, and 2-methoxyethyl methacrylate (meth)acrylic acid.

[0135] By adjusting the number, type, combination, and amount of comonomer components, an adhesive layer with the desired properties corresponding to the purpose can be obtained.

[0136] A polymer with a cross-linked structure introduced into a (meth)acrylic polymer chain can be obtained, for example, by the following methods: (1) a method of polymerizing a (meth)acrylic polymer having functional groups that can react with a cross-linking agent, and then adding a cross-linking agent to react the (meth)acrylic polymer with the cross-linking agent; and (2) a method of introducing a branched structure (cross-linked structure) into the polymer chain by including a polyfunctional compound in the polymer composition. These methods can also be used in combination.

[0137] As specific examples of crosslinking agents in the method of reacting the base polymer with the crosslinking agent described in (1) above, 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 can be listed.

[0138] Crosslinking agents can be used alone or in combination.

[0139] Among crosslinking agents, isocyanate-based crosslinking agents and epoxy-based crosslinking agents are preferred. If the crosslinking agent includes isocyanate-based crosslinking agents and / or epoxy-based crosslinking agents, it can react fully with functional groups such as hydroxyl or carboxyl groups introduced into the base polymer to successfully form a crosslinked structure.

[0140] In the method described in (2) above for including polyfunctional compounds in the polymer composition of the base polymer, the monomer components constituting the (meth)acrylate polymer and the total amount of polyfunctional compounds used to introduce the crosslinking structure can be reacted in one step, or polymerization can be carried out in multiple stages. As a method for carrying out polymerization in multiple stages, the following method can be listed as an example: polymerizing the monofunctional monomers constituting the (meth)acrylate polymer (prepolymerization), preparing a partial polymer (prepolymer composition), adding polyfunctional compounds such as polyfunctional (meth)acrylates to the prepolymer composition, and polymerizing the prepolymer composition with the polyfunctional monomers (formal polymerization).

[0141] The prepolymer composition is a partial polymer comprising a low-degree-of-polymerization polymer and unreacted monomers. Examples of multifunctional compounds include those containing two or more polymerizable functional groups (olefinic unsaturated groups) with unsaturated double bonds per molecule. Multifunctional (meth)acrylates are preferred as multifunctional compounds from the perspective of ease of copolymerization with monomer components of (meth)acrylate polymers. Multifunctional (meth)acrylates are preferred when introducing branched (crosslinked) structures via active energy radiation polymerization (photopolymerization). Furthermore, as multifunctional (meth)acrylates, crosslinked structures utilizing urethane segments can be introduced by using urethane (meth)acrylates having (meth)acryloyl groups at the ends of the urethane chains.

[0142] In one embodiment, the adhesive composition may also comprise an acrylic oligomer. In another embodiment, the adhesive composition may also be photocurable. In this case, the adhesive composition may, for example, comprise a multifunctional compound and a photopolymerization initiator.

[0143] Adhesive compositions may also contain additives. Specific examples of additives include colorants, pigments and other powders, dyes, surfactants, plasticizers, adhesive agents, surface lubricants, leveling agents, softeners, antioxidants, anti-aging agents, light stabilizers, ultraviolet absorbers, polymerization inhibitors, conductive agents, inorganic or organic fillers, metal powders, granular or foil-like materials. Furthermore, redox systems containing a reducing agent within a controllable range may be used. The type, number, combination, and dosage of additives can be appropriately set according to the purpose. By appropriately adjusting the type, combination, and dosage of monomer components, as well as the type, number, combination, and dosage of crosslinking agents, silane coupling agents, and additives, an adhesive composition (resulting in an adhesive layer) with the desired properties corresponding to the purpose can be obtained.

[0144] Other examples of adhesive compositions constituting the adhesive layer include the composition described in Japanese Patent Application Publication No. 2016-94569. The description in that publication is incorporated herein by reference.

[0145] The glass transition temperature of the first adhesive layer 11 is, for example, below -3°C, preferably below -5°C, and more preferably below -6°C. On the other hand, the glass transition temperature of the first adhesive layer 11 is, for example, above -20°C, preferably above -15°C, and more preferably above -13°C. If the glass transition temperature is in such a range, an adhesive layer with excellent impact resistance can be achieved.

[0146] The peak value of the loss tangent tanδ of the first adhesive layer 11 (i.e., tanδ at the glass transition temperature) is, for example, 1.5 or more, preferably 1.6 or more, more preferably 1.7 or more, and even more preferably 1.75 or more.

[0147] On the other hand, the peak value of tanδ of the first adhesive layer 11 is, for example, 3.0 or less, preferably 2.5 or less, and more preferably 2.3 or less.

[0148] 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 in such a range, the transparent component can be firmly bonded to the optical laminate.

[0149] It should be noted that the gel fraction is calculated, for example, as the insoluble component relative to solvents such as ethyl acetate. Specifically, the gel fraction is determined as the mass fraction (in mass%) of the insoluble component of the adhesive constituting the adhesive layer after immersion in ethyl acetate at 23°C for 7 days, relative to the sample before immersion.

[0150] The storage elastic modulus of the first adhesive layer 11 at 25°C is, for example, 1×10⁻⁶.4 Pa~30×10 4 Pa, preferably 2×10 4 Pa ~ 25 × 10 4 Pa, more preferably 3 × 10 Pa 4 Pa~20×10 4 Pa.

[0151] It should be noted that the storage elastic modulus of the adhesive layer is determined according to JIS K 6868, for example, at a heating rate of 5°C / min and a frequency of 1Hz.

[0152] B-2-2. First phase difference film The first phase difference film 14 is, in a sense, flexible.

[0153] 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 bent along the three-dimensional curved surface 21 (see reference). Figure 1 ).

[0154] 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.

[0155] The radius of curvature of the first phase retardation film 14 (more specifically, the radius of curvature in the curved portion of the first phase retardation film 14) is, for example, 1 mm to 200 mm, preferably 2 mm to 100 mm.

[0156] It should be noted that the radius of curvature of each film (layer) is measured, for example, by a laser interferometer, laser displacement meter, spectrometer, or SEM.

[0157] The first phase difference film 14 typically includes a stretched film prepared by stretching a resin film, and / or an orientation fixing layer of a liquid crystal compound.

[0158] In this specification, "alignment-fixing layer of liquid crystal compound" refers to a layer in which the liquid crystal compound is oriented in a specified direction and its orientation state is fixed. It should be noted that "alignment-fixing layer" includes the concept of an alignment-cured layer obtained by curing liquid crystal monomers as described below.

[0159] The first retardation film 14 can have a single-layer structure or a multilayer structure. In one embodiment, the first retardation film 14 has a single-layer structure.

[0160] The first phase difference film 14, which has a single-layer structure, is typically composed of the stretch film with in-plane phase difference described above.

[0161] Materials used for stretch films include, for example, cycloolefin (COP) resins, cellulose resins, polycarbonate (PC) resins, and (meth)acrylic resins, with COP resins and cellulose resins being preferred.

[0162] As a specific example of COP-based resins, polynorbornene-based resins can be cited.

[0163] Triacetyl cellulose (TAC) is a specific example of a cellulose-based resin.

[0164] The materials used for stretch film can be used alone or in combination.

[0165] In one embodiment, the first phase difference film 14 having a single-layer structure comprises a COP-based resin.

[0166] For the surface of the first retardation film 14 having a single-layer structure, a surface treatment layer is provided as needed. Examples of surface treatment layers include hard coatings, anti-reflective layers, anti-adhesion layers, and anti-glare treatment layers. The surface treatment layer is preferably provided on the surface of the first retardation film 14 opposite to the polarizer 13.

[0167] B-2-3. Polarizer The polarizer 13 is, in a sense, flexible.

[0168] With the optical laminate 1 attached to the three-dimensional curved surface 21, at least a portion of the polarizer 13 bends along the three-dimensional curved surface 21 (see reference). Figure 1 ).

[0169] The radius of curvature of the polarizer 13 (more specifically, the radius of curvature in the bent portion of the polarizer 13) is, for example, 1 mm to 200 mm, preferably 2 mm to 100 mm.

[0170] The polarizer 13 has any suitable configuration. For example, the polarizer can be made of a single layer of resin film, or it can be a polarizer obtained by using two or more layers of laminate.

[0171] Specific examples of polarizers composed of single-layer resin films include polarizers obtained by dyeing and stretching hydrophilic polymer films such as polyvinyl alcohol (PVA)-based resin films, partially formalized PVA-based resin films, and partially saponified ethylene-vinyl acetate copolymer-based films using dichroic substances such as iodine or dichroic dyes; and polyene-based oriented films such as dehydrated PVA products or dehydrochlorinated polyvinyl chloride products. From the perspective of superior optical properties, polarizers obtained by dyeing PVA-based resin films with iodine and then uniaxially stretching them are preferred.

[0172] Specific examples of polarizers obtained using laminates include those using a resin substrate and a PVA-based resin layer (PVA-based resin film) laminated on the resin substrate, or those using a resin substrate and a PVA-based resin layer coated on the resin substrate. A polarizer obtained using a laminate of a resin substrate and a PVA-based resin layer coated on the resin substrate can be manufactured, for example, by coating a PVA-based resin solution onto a resin substrate and drying it to form a PVA-based resin layer on the resin substrate, thus obtaining a laminate of the resin substrate and the PVA-based resin layer; stretching and dyeing the laminate to form a polarizer from the PVA-based resin layer. In one embodiment, a polyvinyl alcohol-based resin layer comprising 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 for stretching. Furthermore, stretching may, if necessary, further include air stretching of the laminate at a high temperature (e.g., above 95°C) prior to stretching in the aqueous boric acid solution. Furthermore, in one embodiment, the laminate is subjected to a drying shrinkage treatment that causes it to shrink by more than 2% in the width direction while being heated and conveyed along the length direction. Typically, the manufacturing method of this embodiment includes sequentially performing an air-assisted stretching treatment, a dyeing treatment, an underwater stretching treatment, and a drying shrinkage treatment on the laminate. By introducing assisted stretching, even when PVA is coated on a thermoplastic resin, the crystallinity of PVA can be improved, resulting in high optical properties. Furthermore, by simultaneously improving the orientation of PVA beforehand, problems such as decreased orientation and dissolution of PVA can be prevented when immersed in water during subsequent dyeing and stretching processes, thus achieving high optical properties. Moreover, when the PVA-based resin layer is immersed in a liquid, compared to when the PVA-based resin layer does not contain halides, the disorder of polyvinyl alcohol molecule orientation and the reduction of orientation can be suppressed. Therefore, the optical properties of the polarizer obtained through processing steps such as dyeing and underwater stretching in which the laminate is immersed in a liquid can be improved. Furthermore, by utilizing the drying shrinkage treatment to shrink the laminate along the width direction, optical properties can be improved. The resulting resin substrate / polarizer laminate can be used directly (i.e., the resin substrate can also be used as a protective layer for the polarizer), or the resin substrate can be peeled off from the resin substrate / polarizer laminate and any suitable protective layer corresponding to the purpose can be laminated on the peeled surface for use.

[0173] Detailed descriptions of the manufacturing method of such a polarizer are provided, for example, in Japanese Patent Application Publication No. 2012-73580 and Japanese Patent No. 6470455. The entire contents of these publications are incorporated herein by reference.

[0174] The aforementioned dyeing using iodine is performed, for example, by immersing the PVA-based resin film in an aqueous iodine solution. The stretching ratio for the uniaxial stretching is preferably 3 to 7 times. Stretching can be performed after dyeing or simultaneously with dyeing. Alternatively, dyeing can be performed after stretching. Depending on the needs, the PVA-based resin film may undergo swelling treatment, crosslinking treatment, washing treatment, drying treatment, etc. For example, by immersing the PVA-based resin film in water for washing before dyeing, not only can stains and anti-blocking agents on the surface of the PVA-based resin film be washed away, but the PVA-based resin film can also swell, thus suppressing uneven dyeing.

[0175] The polarizer 13 typically exhibits absorption dichroism at any wavelength from 380 nm to 780 nm. The transmittance of the polarizer 13 is, for example, 41.5% to 46.0%, preferably 43.0% to 46.0%, more preferably 44.5% to 46.0%. The polarization degree of the polarizer 13 is preferably 97.0% or more, more preferably 99.0% or more, and even more preferably 99.9% or more.

[0176] B-2-4. Protective layer Protective layer 16 is, in a sense, flexible.

[0177] With the optical laminate 1 attached to the three-dimensional curved surface 21, at least a portion of the protective layer 16 is bent along the three-dimensional curved surface 21 (see reference). Figure 1 ).

[0178] In one embodiment, the radius of curvature of the protective layer 16 is smaller than the radius of curvature of the polarizer 13.

[0179] The radius of curvature of the protective layer 16 (more specifically, the radius of curvature in the curved portion of the protective layer 16) is, for example, 1 mm to 200 mm, preferably 2 mm to 100 mm.

[0180] The protective layer 16 comprises any suitable transparent resin.

[0181] Examples of transparent resins include polynorbornene and other cyclic olefin (COP) resins; polyethylene terephthalate (PET) and other polyester resins; triacetyl cellulose (TAC) and other cellulose resins; polycarbonate (PC) resins; (meth)acrylic acid resins; polyvinyl alcohol resins; polyamide resins; polyimide resins; polyethersulfone resins; polysulfone resins; polystyrene resins; polyolefin resins; and acetate resins.

[0182] In addition, thermosetting resins or UV-curing resins such as (meth)acrylic acid-based, urethane-based, (meth)acrylate urethane-based, epoxy-based, and silicone-based resins can also be listed. Furthermore, glassy polymers such as siloxane polymers can also be listed. Furthermore, polymer films 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 on the side chains and a thermoplastic resin having substituted or unsubstituted phenyl and nitrile groups on the side chains can be used; for example, a resin composition having an alternating copolymer formed from isobutylene and N-methylmaleimide and an acrylonitrile-styrene copolymer can be listed. The polymer film can, for example, be an extruded product of the above-mentioned resin composition.

[0183] The materials for the protective layer can be used alone or in combination.

[0184] B-2-5. Second phase difference film The second phase difference film 15 is, in a sense, flexible.

[0185] 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 bent along the three-dimensional curved surface 21 (see reference). Figure 1 ).

[0186] In one embodiment, the radius of curvature of the second retardation film 15 is smaller than the radius of curvature of the polarizer 13. In the illustrated example, the radius of curvature of the second retardation film 15 is smaller than the radius of curvature of the protective layer 16.

[0187] The radius of curvature of the second phase retardation film 15 (more specifically, the radius of curvature in the curved portion of the second phase retardation film 15) is, for example, 1 mm to 200 mm, preferably 2 mm to 100 mm.

[0188] The second phase difference film 15 has any suitable configuration.

[0189] The second phase difference film 15 typically includes a stretched film prepared by stretching a resin film, and / or an orientation fixing layer of a liquid crystal compound.

[0190] In one embodiment, the second retardation film 15 comprises an alignment fixing layer of a liquid crystal compound.

[0191] If the second retardation film includes an alignment fixing layer of a liquid crystal compound, the difference between nx and ny in the second retardation film can be significantly increased compared to non-liquid crystal materials, thus significantly reducing the thickness of the retardation film with the desired in-plane retardation. As a result, the optical laminate can be further thinned.

[0192] The second retardation film 15 can have a single-layer structure or a multilayer structure. In one embodiment, the second retardation film 15 has a multilayer structure. More specifically, the second retardation film 15 includes multiple alignment fixing layers of liquid crystal compounds.

[0193] like Figure 3 As shown, in one embodiment, the second retardation film 15 includes two alignment fixing layers of liquid crystal compounds. Hereinafter, the two alignment fixing layers of liquid crystal compounds included in the second retardation film 15 are sometimes referred to as the first liquid crystal alignment fixing layer 151 and the second liquid crystal alignment fixing layer 152.

[0194] The first liquid crystal alignment fixing layer 151 is located between the polarizer 13 and the second liquid crystal alignment fixing layer 152 (see reference). Figure 1 In the example shown, the first liquid crystal alignment fixing layer 151 is located between the protective layer 16 and the second liquid crystal alignment fixing layer 152 (see figure). Figure 1 Therefore, the first liquid crystal alignment fixing layer 151 is attached to the protective layer 16 via the third adhesive layer 17c.

[0195] The second liquid crystal alignment fixing layer 152 is located on the opposite side of the polarizer 13 relative to the first liquid crystal alignment fixing layer 151 (see reference). Figure 1 ).

[0196] The first liquid crystal alignment fixing layer 151 typically functions as a λ / 2 plate. The second liquid crystal alignment fixing layer 152 typically functions as a λ / 4 plate.

[0197] With this configuration, the wavelength dispersion characteristics of the second retardation film can be made close to the ideal inverse wavelength dispersion characteristics. Therefore, excellent anti-reflection properties can be imparted to the optical laminate.

[0198] It should be noted that the first liquid crystal alignment fixing layer 151 can also function as a λ / 4 plate, and the second liquid crystal alignment fixing layer 152 can function as a λ / 2 plate.

[0199] The angle between the absorption axis direction of the polarizer 13 and the slow axis direction of the first liquid crystal alignment fixing layer 151 is, for example, 10° to 20°, preferably 12° to 18°, and more preferably 14° to 16°.

[0200] Furthermore, the angle between the absorption axis direction of the polarizer 13 and the slow axis direction of the second liquid crystal alignment fixing layer 152 is, for example, 70° to 80°, preferably 72° to 78°, and more preferably 74° to 76°.

[0201] With this configuration, the wavelength dispersion characteristics of the second retardation film 15 can be made closer to the ideal inverse wavelength dispersion characteristics. Therefore, excellent anti-reflection properties can be stably imparted to the optical laminate.

[0202] It should be noted that the range of the angle between the absorption axis direction of the polarizer and the slow axis direction of the second liquid crystal alignment fixing layer and the range of the angle between the absorption axis direction of the polarizer and the slow axis direction of the third liquid crystal alignment fixing layer can also be opposite.

[0203] In the first liquid crystal alignment fixing layer 151, typically, the rod-shaped liquid crystal compound is aligned (plane alignment) in a state where it is arranged along the slow axis direction of the first liquid crystal alignment fixing layer 151.

[0204] Examples of liquid crystal compounds include those 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 can be used individually or in combination.

[0205] The liquid crystal properties of liquid crystal compounds can be manifested by either lyotropic or thermotropic mechanisms.

[0206] When the liquid crystal compound contains liquid crystal monomers, these monomers are preferably polymerizable or crosslinkable monomers. The orientation state of the liquid crystal monomers can be fixed by polymerizing or crosslinking them (i.e., curing). After aligning the liquid crystal monomers, for example, if the monomers are polymerized or crosslinked together, the aforementioned orientation state can be fixed. Here, polymers are formed through polymerization, and three-dimensional mesh structures are formed through crosslinking, but these are non-liquid crystals. Therefore, the formed first liquid crystal alignment-fixed layer, for example, does not cause the temperature-induced phase transition to liquid crystal, glassy, ​​or crystalline phase characteristic of liquid crystal compounds. As a result, the second retardation film can possess extremely excellent stability unaffected by temperature changes.

[0207] Any suitable monomer can be used as the liquid crystal monomer. Examples of liquid crystal monomers include polymerizable mesocrystalline compounds described in Japanese Patent Application Publication No. 2002-533742 (WO00 / 37585), EP358208 (US5211877), EP66137 (US4388453), WO93 / 22397, EP0261712, DE19504224, DE4408171, and GB2280445.

[0208] Specific examples of such polymeric mesocrystalline compounds include BASF's LC242, Merck's E7, and Wacker-Chem's LC-Sillicon-CC3767.

[0209] The alignment fixing layer of the liquid crystal compound can be formed by performing any suitable alignment treatment on the surface of any suitable coating substrate, coating the surface with a coating liquid containing the liquid crystal compound, so that the liquid crystal compound is aligned in a direction corresponding to the above-mentioned alignment treatment, and fixing the alignment state.

[0210] As an orientation treatment, examples include mechanical orientation treatment, physical orientation treatment, and chemical orientation treatment.

[0211] Specific examples of liquid crystal compounds and detailed methods for forming the alignment fixing layer are described in Japanese Patent Application Publication No. 2006-163343. The contents of that publication are incorporated herein by reference.

[0212] The thickness of the first liquid crystal alignment fixing layer 151 is arbitrarily and appropriately adjusted in order to obtain the desired in-plane phase difference. The thickness of the first liquid crystal alignment fixing 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 fixing layer 151 is typically 1.0 μm.

[0213] The second liquid crystal alignment fixing layer 152 is described in the same manner as the first liquid crystal alignment fixing layer 151. Therefore, a detailed description of the second liquid crystal alignment fixing layer 152 is appropriately omitted.

[0214] In the example shown, the second liquid crystal alignment fixing layer 152 is attached to the first liquid crystal alignment fixing layer 151 via an adhesive layer 153. The adhesive layer 153 is described in the same manner as the first adhesive layer 17a described above. Therefore, a detailed description of the adhesive layer 153 is omitted.

[0215] B-2-6. Second adhesive layer like Figure 2 As shown, the second adhesive layer 12 is typically located at the end (the other end) opposite to the first adhesive layer 11 in the optical laminate 1.

[0216] In one embodiment, the second adhesive layer 12 is disposed on the surface of the second phase difference film 15 opposite to the polarizer 13.

[0217] The second adhesive layer 12 is made of any suitable adhesive. For example, the same adhesive as the first adhesive layer 11 can be used as the adhesive constituting the second adhesive layer 12.

[0218] The storage elastic modulus of the second adhesive layer 12 at 25°C is, for example, 2 × 10⁻⁶. 4 Pa ~ 16 × 10 4 Pa, preferably 4 × 10 4Pa ~ 15 × 10 4 Pa.

[0219] B-2-7. Variation Example Figure 2 The optical laminate 1 shown has a protective layer 16 and a second retardation film 15 as described above. However, the configuration of the optical laminate 1 is not limited to this.

[0220] like Figure 4 As shown, in one embodiment, the image display device 100 may also include only one of the protective layer 16 and the second retardation film 15. That is, Figure 4 The optical laminate 1 shown comprises, in sequence, the first adhesive layer 11, the first retardation film 14, the first bonding layer 17a, the polarizer 13, the second bonding layer 17b, the second retardation film 15 or the protective layer 16, and the second adhesive layer 12. With this configuration, the optical laminate can be made thinner.

[0221] B-3. ​​Image Display Panel like Figure 1 As shown, the image display panel 3 includes an image display unit 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 reference). Figure 2 ).

[0222] 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 bent along the three-dimensional curved surface 21.

[0223] The radius of curvature of the image display panel 3 is typically smaller than the radius of curvature of the three-dimensional surface 21. In the example shown, the radius of curvature of the image display panel 3 is smaller than the radii of curvature of the first retardation film 14, the polarizer 13, the second retardation film 15, and the protective layer 16 (see reference). Figure 2 ).

[0224] The radius of curvature of the image display panel 3 (more specifically, the radius of curvature in the curved portion of the image display panel 3) is, for example, 1 mm or more, preferably more than 2 mm, and more preferably 10 mm or more.

[0225] On the other hand, the radius of curvature of the image display panel 3 (more specifically, the radius of curvature in 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, further preferably less than 45 mm, and especially preferably less than 30 mm.

[0226] C. Manufacturing method of image display device Next, a method for manufacturing an optical laminate according to one embodiment will be described.

[0227] In one embodiment, the method for manufacturing an image display device sequentially includes: a step of preparing the optical laminate 1 described above; a step of attaching the optical laminate 1 to the image display panel 3 via a second adhesive layer 12; and a step of attaching the optical laminate 1 to the three-dimensional curved surface 21 of the transparent member 2 via a first adhesive layer 11.

[0228] That is, in this embodiment, the optical laminate 1 (hereinafter, sometimes referred to as the laminate with the panel attached), which has 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, so that the first adhesive layer 11 of the laminate with the panel comes into contact with the three-dimensional curved surface 21.

[0229] In this method, since the radius of curvature R of the three-dimensional surface, the thickness d1 of the first adhesive layer and the thickness d2 of the second adhesive layer satisfy the above equation (1), the laminate with the panel bends smoothly along the three-dimensional surface and is stably attached to the three-dimensional surface.

[0230] Thus, an image display device is manufactured.

[0231] Furthermore, in the above-described method for manufacturing an image display device, an optical laminate is attached to a transparent component having a three-dimensional curved surface, but the method for manufacturing an image display device is not limited to this.

[0232] In another embodiment, the method for manufacturing an image display device sequentially includes: a step of preparing the aforementioned optical laminate 1; a step of attaching the optical laminate 1 to an image display panel 3 via a second adhesive layer 12; a step of forming a three-dimensional curved surface on the image display panel 3 and the optical laminate 1 (specifically, a laminate with a panel); and a step of attaching the transparent member 2 having the three-dimensional curved surface 21 via a first adhesive layer 11. The transparent member 2 may have the three-dimensional curved surface 21 formed during the step of attaching it to the image display panel 3 and the optical laminate 1 (specifically, a laminate with a panel), or the three-dimensional curved surface 21 may be pre-formed.

[0233] In another embodiment, the method for manufacturing an image display device includes, in sequence: a step of preparing the optical laminate 1 described above; a step of attaching the optical laminate 1 to the image display panel 3 via a second adhesive layer 12; a step of attaching the optical laminate 1 to the transparent member 2 via a first adhesive layer 11; and a step of forming a three-dimensional curved surface 21 on the transparent member 2 with the image display panel 3 and the optical laminate 1 (specifically, a laminate with a panel) attached to the transparent member 2.

[0234] That is, in this embodiment, after attaching the laminate with the panel to the transparent member 2 which does not have a three-dimensional curved surface, the transparent member 2 with the laminate with the panel attached is processed to form a three-dimensional curved surface 21.

[0235] Examples of processing methods for forming three-dimensional curved surfaces include heat forming, pressure forming, stretch forming, and shrink forming.

[0236] During the processing of forming three-dimensional curved surfaces, laminates with panels and / or transparent components are heated to, for example, 50°C to 120°C.

[0237] By means of this method, since the radius of curvature R of the three-dimensional surface, the thickness d1 of the first adhesive layer and the thickness d2 of the second adhesive layer satisfy the above equation (1), the laminate with the panel deforms following the transparent component, and thus a three-dimensional surface can be stably formed in the image display device.

[0238] In these embodiments, the pre-prepared optical laminate 1 may or may not have a first adhesive layer 11. When the pre-prepared optical laminate 1 does not have a first adhesive layer 11, the first adhesive layer 11 is formed at one end of the optical laminate 1 in the lamination direction (on the first retardation film 14 in the example) after the optical laminate 1 is attached to the image display panel 3 through the second adhesive layer 12.

[0239] D. Applications of image display devices Examples of such image display devices include liquid crystal displays (LCDs) and organic EL displays. Specific examples of image display devices include mobile phones (smartphones), laptops, and furniture. By molding the edges of mobile phones and laptops with three-dimensional curved surfaces, the screen size can be maximized. Furniture generally has three-dimensional curved surfaces; by combining it with an image display device that also has three-dimensional curved surfaces, image display functionality can be achieved without compromising practicality.

[0240] Example The present invention will now be specifically described through examples, but the present invention is not limited to these examples. It should be noted that the methods for measuring each characteristic are as follows.

[0241] (1) Measurement of phase difference The in-plane phase difference between the first and second phase retardation films used in the examples and comparative examples was automatically measured using a KOBRA-WPR meter manufactured by Oji. The measurement wavelength was 550 nm, and the measurement temperature was 25 °C.

[0242] (2) Attachment test of optical laminates to three-dimensional curved surfaces The test samples obtained in the examples and comparative examples were placed on a reflective plate, and the ratio of the bonding area to the three-dimensional curved surface was calculated using the image processing software ImageJ. The results are shown in Tables 1 to 3.

[0243] <Preparation of Optically Transparent Adhesive Films> <Preparation Example 1> (Preparation of acrylic acid oligomers) First, in a reaction vessel equipped with a stirrer, thermometer, reflux cooler, and nitrogen inlet, a mixture containing 60 parts by mass of dicyclopentyl 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 under a nitrogen atmosphere for 1 hour. 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 at 70°C for 2 hours under a nitrogen atmosphere, and then at 80°C for 2 hours (polymerization reaction). Then, the reaction solution was heated at 130°C to volatilize and remove the 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.

[0244] (Preparation of prepolymer composition) In a flask, two first photopolymerization initiators (totaling 0.062 parts by mass) were added to a monomer mixture comprising 71 parts by mass of n-butyl acrylate (BA), 13 parts by mass of N-vinyl-2-pyrrolidone (NVP), 3 parts by mass of acrylamide (ACMO), and 13 parts by mass of 4-hydroxybutyl acrylate (4HBA). The mixture was then subjected to ultraviolet light irradiation under a nitrogen atmosphere, causing a portion of the monomer components to polymerize to obtain a prepolymer composition. The molecular weight between the intertwined points of n-butyl acrylate (BA) was 15,000. As the first photopolymerization initiators, 0.031 parts by mass of BASF's "Omnirad 184" (1-hydroxy-cyclohexyl-phenyl-ketone) and 0.031 parts by mass of BASF's "Omnirad 651" (2,2-dimethoxy-2-phenylacetophenone) were used. Ultraviolet irradiation continued until the viscosity of the composition reached approximately 20 Pa·s. The viscosity was measured using a Type B viscometer under the conditions of rotor No. 5, rotor speed 10 rpm, and temperature 30°C. The resulting prepolymer composition is a partial polymer containing a photopolymer (photopolymer P1a) and monomer components that have not undergone polymerization (residual monomers).

[0245] (Preparation of adhesive composition) Next, 100 parts by weight of the prepolymer composition, 3 parts by weight of the aforementioned acrylic oligomer, 0.6 parts by weight of the urethane acrylate oligomer (UAO) (brand name "UN-350", manufactured by Negami Kogyosha) as the second photopolymerizable polyfunctional compound, 0.4 parts by weight of the second photopolymerization initiator, 0.5 parts by weight of the antioxidant (brand name "Irganox 1010", manufactured by BASF), 0.2 parts by weight of the rust inhibitor (brand name "BT-120", 1,2,3-benzotriazole, manufactured by Johoku Chemical Industry Co., Ltd.), and 0.3 parts by weight of the silane coupling agent (brand name "KBM-403", manufactured by Shin-Etsu Chemical Industry Co., Ltd.) were mixed to obtain an adhesive composition. The amount of the second photopolymerizable polyfunctional compound (crosslinking agent) per 100 parts by weight of monomer components was 0.55 parts by weight. As the second photopolymerization initiator, BASF's "Omnirad 819" (bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide) was used.

[0246] (Making the basic adhesive sheet) Next, an adhesive composition is applied to the release-treated surface of a first release liner (product name "DIAFOIL MRF", thickness 75 μm, manufactured by Mitsubishi Chemical Co., Ltd.), which has a release-treated surface on one side, to form a coating film. Then, a second release liner (product name "DIAFOIL MRE", thickness 75 μm, manufactured by Mitsubishi Chemical Co., Ltd.), which also has a release-treated surface on one side, is bonded to the coating film on the first release liner. Next, the coating film between the release liners is irradiated with ultraviolet light from the second release liner side to photocur the coating film, forming an adhesive layer with a thickness of 100 μm (UV irradiation process). During UV irradiation, a black light lamp (wavelength 320 nm–400 nm, manufactured by Toshiba Co., Ltd.) is used as the light source, and the illuminance is set to 6.5 mW / cm². 2 The cumulative irradiation intensity was set to 1500 mJ / cm². 2 In the UV irradiation process, a photopolymerization reaction is carried out in the coating film using a reaction system comprising the aforementioned residual monomer, additional monomer, and a second photopolymerizable multifunctional compound (crosslinking agent) to form a photopolymerizable polymer P1b with a crosslinked structure. Furthermore, since this photopolymerization reaction occurs around the photopolymerizable polymer P1a, the photopolymerizable polymer P1b is formed around the photopolymerizable polymer P1a. The adhesive layer formed in this process comprises such photopolymerizable polymers P1a and P1b as a base polymer P1. Following the above procedure, a base adhesive sheet with double-sided release liner (first release liner / base adhesive sheet (100 μm thickness) / second release liner) is produced.

[0247] (Preparation of the solution with added components) A solution of post-addition components was prepared by mixing 6.0 parts by weight of trimethylolpropane triacrylate (TMPTA) (brand name "Viscoat#295", manufactured by Osaka Organic Chemical Co., Ltd.) as the first photopolymerizable polyfunctional compound, 1.2 parts by weight of ethoxylated bisphenol A diacrylate (BPAEODE) (brand name "ABE-300", manufactured by Shin-Nakamura Chemical Co., Ltd.) as another first photopolymerizable polyfunctional compound, 0.3 parts by weight of the third photopolymerization initiator, 7.0 parts by weight of ultraviolet absorber (brand name "Tinosorb S", manufactured by BASF), and 90.7 parts by weight of ethyl acetate as a solvent. The components other than the solvent in the solution were post-addition components. "Omnirad 819" manufactured by BASF was used as the third photopolymerization initiator.

[0248] (Fabrication of optical adhesive sheets) First, after peeling the second release liner from the aforementioned base adhesive sheet with the release liner, a coating of the added component solution is applied to the exposed surface of the base adhesive sheet to a thickness of 20 μm (coating treatment). For coating, a rod coater RDS No. 10 manufactured by RDSPECIALTIES was used. Next, the mixture was dried in a desiccator at 110°C for 60 seconds. Through the coating and drying treatments, the added components (first photopolymerizable multifunctional compound, third photopolymerization initiator, and UV absorber) penetrate into the base adhesive sheet, while the solvent is vaporized. Through the penetration of the added components relative to the base adhesive sheet, a photocurable optical adhesive sheet is formed. The prepolymer composition described above contains 6.0 parts by mass of TMPTA, 1.2 parts by mass of BPAEODE, 0.3 parts by mass of the third photopolymerization initiator (Omnirad 819), and 7.0 parts by mass of the UV absorber (Tinosorb S) per 100 parts by mass. Next, on the adhesive sheet on the first release liner, the release-treated surface of the third release liner (brand name "DIAFOIL MRE", thickness 75μm, manufactured by Mitsubishi Chemical Co., Ltd.) with a release-treated surface on one side is attached.

[0249] Proceed as described above to fabricate an adhesive sheet with release liner (first release liner / adhesive sheet (100 μm thick) / third release liner). The adhesive sheet is a photocurable optical adhesive sheet containing a base polymer, a first photopolymerizable multifunctional compound (TMPTA, BPAEODE), and a third photopolymerization initiator. Use this optical adhesive sheet as an optically transparent adhesive film.

[0250] <Example 1> <<Preparation of the Polarizer>> As a thermoplastic resin substrate, a strip-shaped amorphous polyethylene terephthalate copolymer film (thickness: 100 μm) with a Tg of about 75 °C was used, and one side of the film was subjected to corona treatment.

[0251] 13 parts by mass of potassium iodide were added to 100 parts by mass of a PVA-based resin prepared by mixing polyvinyl alcohol (degree of polymerization 4200, degree of saponification 99.2 mol%) and acetyl-modified PVA (manufactured by Japan Synthetic Chemical Industry Co., Ltd., trade name "GOHSEFIMER") in a ratio of 9:1. The resulting substance was dissolved in water to prepare a PVA aqueous solution (coating solution).

[0252] By coating the above-mentioned PVA aqueous solution onto the corona-treated surface of a thermoplastic resin substrate and drying it at 60°C, a PVA-based resin layer with a thickness of 13 μm is formed on the thermoplastic resin substrate.

[0253] The resulting laminate was stretched uniaxially to 2.4 times its original length in an oven at 130°C (air-assisted stretching treatment).

[0254] Next, the laminate was immersed in an insoluble bath (an aqueous solution of boric acid prepared by mixing 4 parts by mass with 100 parts by mass of water) at a liquid temperature of 40°C for 30 seconds (insoluble treatment).

[0255] Next, the laminate is immersed in a staining bath at 30°C (an iodine aqueous solution prepared by mixing iodine and potassium iodide in a mass ratio of 1:7 relative to 100 parts by mass of water) for 60 seconds (staining treatment) while adjusting the concentration so that the final polarizer's monomer transmittance (Ts) becomes the desired value.

[0256] Next, the laminate was immersed in a crosslinking bath at 40°C (an aqueous solution of boric acid prepared by mixing 3 parts by mass of potassium iodide and 5 parts by mass of boric acid with 100 parts by mass of water) for 30 seconds (crosslinking treatment).

[0257] 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, while being uniaxially stretched (underwater stretching treatment) between rollers with different circumferential speeds along the longitudinal direction (length direction) with a total stretching ratio of 5.5.

[0258] The laminate was then immersed in a washing bath at 20°C (an aqueous solution of 4 parts by mass of potassium iodide relative to 100 parts by mass of water) for washing treatment.

[0259] The laminate is then dried in an oven at approximately 90°C while being brought into contact with heated rollers made of SUS at a surface temperature of approximately 75°C (drying shrinkage treatment).

[0260] This process forms a polarizer on a thermoplastic resin substrate. The thickness d3 of the polarizer is approximately 5.0 μm.

[0261] <<Attachment of the first phase retardation film relative to the polarizer>> A first retardation film (manufactured by ZEON Corporation, Japan, ZD12) with a single-layer structure containing a stretched film of COP was prepared. The first retardation film has a refractive index of nx > ny > nz. The in-plane phase difference Re(550) of the first retardation film is 99 nm. The thickness d5 of the first retardation film is 25 μm.

[0262] Next, the polarizer is bonded to the first phase difference film using a UV-curable adhesive. Then, the UV-curable adhesive is irradiated with ultraviolet light to cure it, forming a UV adhesive layer containing the cured UV adhesive. The thickness of the UV adhesive layer is 1 μm.

[0263] <<Attachment of the protective layer to the polarizer>> Next, the thermoplastic resin substrate is peeled off from the polarizer.

[0264] Subsequently, a TAC film (manufactured by Fujifilm, trade name: TJ25UL, Re(550): 0nm) as a protective layer is attached to the surface of the polarizer opposite to the first phase difference film. The thickness d7 of the protective layer is 25μm.

[0265] Subsequently, the UV-curable adhesive is irradiated with ultraviolet light to cure it, forming a UV adhesive layer containing the cured UV-curable adhesive. The thickness of the UV adhesive layer is 1 μm.

[0266] Thus, a polarizer with a stacked structure of a first phase difference film / UV adhesive layer / polarizer / UV adhesive layer / protective layer is prepared.

[0267] In the polarizer, the angle between the absorption axis of the polarizer and the slow axis of the first phase difference film is 45°.

[0268] <<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 (manufactured by BASF: trade name "Paliocolor LC242", denoted by the following formula) exhibiting a nematic liquid crystal phase and 3 parts by mass of a photopolymerization initiator for the polymerizable liquid crystal compound (manufactured by BASF: trade name "Irgacure 907") in 40 parts by mass of toluene.

[0269] [Chemical Formula 1] The surface of a polyethylene terephthalate (PET) film (38 μm thick), which serves as the coating substrate, is rubbed with a friction cloth to perform an orientation treatment. The orientation treatment direction is set to be 15° relative to the absorption axis of the polarizer when viewed from the visual confirmation side when it is attached to the polarizer (described later).

[0270] The liquid crystal coating liquid was applied to the orientation treatment surface using a bar coater, and the liquid crystal compound was oriented by heating and drying at 90°C for 2 minutes.

[0271] The liquid crystal layer formed in this manner was irradiated with a metal halide lamp at a concentration of 1 mJ / cm². 2 The liquid crystal layer is cured by light, thereby forming a first liquid crystal alignment fixing layer on the PET film. The thickness of the first liquid crystal alignment fixing layer is 2 μm.

[0272] The first liquid crystal alignment fixing layer has a refractive index of nx > ny = nz. The in-plane phase difference Re(550) of the first liquid crystal alignment fixing layer is 270 nm. That is, the first liquid crystal alignment fixing layer can function as a λ / 2 plate.

[0273] In addition, except that the alignment processing direction is changed to a 75° angle relative to the absorption axis of the polarizer when viewed from the visual confirmation side, a second liquid crystal alignment fixing layer (λ / 4 plate) is formed on the PET film in the same manner as described above. The in-plane phase difference Re (550) of the second liquid crystal alignment fixing layer is 140 nm. That is, the second liquid crystal alignment fixing layer can function as a λ / 4 plate.

[0274] Next, the first liquid crystal alignment fixing layer and the second liquid crystal alignment fixing layer are bonded together using a UV-curable adhesive. Then, the UV-curable adhesive is irradiated with ultraviolet light to cure it. This forms a UV adhesive layer containing the cured UV-curable adhesive. The thickness of the UV adhesive layer is 1 μm.

[0275] Next, the PET film (coating substrate) is peeled off from the first liquid crystal alignment fixing layer.

[0276] Thus, a second retardation film with a stacked structure of a first liquid crystal alignment fixing layer (λ / 2 plate), a UV adhesive layer, and a second liquid crystal alignment fixing layer (λ / 4 plate) on a PET film (coating substrate) is prepared. The thickness d6 of the second retardation film is 4 μm.

[0277] <<Attachment of the second phase retardation film to the polarizer>> Next, the protective layer of the polarizer is bonded to the first liquid crystal alignment fixing layer of the second retardation film using a UV-curable adhesive. Then, the UV-curable adhesive is irradiated with ultraviolet light to cure it, forming a UV adhesive layer containing the cured UV adhesive. The thickness of the UV adhesive layer is 1 μm.

[0278] Next, the PET film (coating substrate) is peeled off from the second liquid crystal alignment fixing layer.

[0279] Thus, an intermediate laminate with a stacked structure of a first phase retardation film / UV adhesive layer / polarizer / UV adhesive layer / protective layer / UV adhesive layer / second phase retardation film is prepared.

[0280] In the intermediate stack, the angle between the absorption axis direction of the polarizer and the slow axis direction of the first liquid crystal alignment fixing layer is 15°, and the angle between the absorption axis direction of the polarizer and the slow axis direction of the second liquid crystal alignment fixing layer is 75°.

[0281] <<Formation of the First Adhesive Layer>> Next, the optically transparent adhesive film obtained in Preparation Example 1 is 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 is 300 μm.

[0282] <<Formation of the Second Adhesive Layer>> Furthermore, a (meth)acrylic adhesive is coated on 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 is 5 μm.

[0283] Through the above, an optical laminate with a stacked structure of a first adhesive layer / a first retardation film / UV adhesive layer / polarizer / UV adhesive layer / protective layer / UV adhesive layer / a second retardation film / a second adhesive layer is prepared.

[0284] <<Preparation of Test Samples>> Next, an acrylic resin film (manufactured by Nitto Denko Co., Ltd., trade name: CAT film) is attached to the surface of the second adhesive layer opposite to the second phase difference film as a substitute for the image display panel. The thickness d4 of the acrylic resin film is 40 μm.

[0285] Next, the optical laminate is attached to the cover glass (transparent component) with a three-dimensional curved surface through the first adhesive layer. The three-dimensional curved surface is concave and has a radius of curvature of 38.6 mm.

[0286] More specifically, after placing the coverslip in the curved lens bonding device (manufactured by Asano Labs, TFH-0321-UD), the optical laminate with the acrylic resin film is arranged opposite each other with the first adhesive layer and the three-dimensional curved surface of the coverslip spaced apart.

[0287] Next, the mold, which has a convex surface corresponding to the three-dimensional curved surface of the cover glass, is brought into contact with the optical laminate from the side opposite to the cover glass, and the cover glass is moved toward the optical laminate. The temperature of the mold is 95°C.

[0288] This allows the first adhesive layer of the optical laminate to come into contact with the three-dimensional curved surface of the cover glass.

[0289] Through the above, a test sample was obtained that has a transparent component with a three-dimensional curved surface, an optical laminate, and an image display panel as substitutes. The values ​​of the above formula (1) in this test sample are shown in Table 1.

[0290] <Example 2> 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. Otherwise, the same procedure as in Example 1 was followed to obtain the test sample. The values ​​of the above formula (1) in the test sample are shown in Table 1.

[0291] <Example 3> The thickness d2 of the second adhesive layer was changed to 25 μm, and the same procedure as in Example 1 was followed to obtain the test sample. The values ​​of the above formula (1) in the test sample are shown in Table 1.

[0292] <Example 4> 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 coverslip was changed to 51.5 mm. Otherwise, the same procedure as in Example 1 was followed to obtain the test sample. The values ​​of the above formula (1) in the test sample are shown in Table 1.

[0293] <Example 5> The thickness d1 of the first adhesive layer was changed to 300 μm, and the test sample was obtained in the same manner as in Example 4. The values ​​of the above formula (1) in the test sample are shown in Table 1.

[0294] <Example 6> 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. Otherwise, the test sample was obtained in the same manner as in Example 4. The values ​​of the above formula (1) in the test sample are shown in Table 1.

[0295] <Example 7> The thickness d2 of the second adhesive layer was changed to 25 μm, and the test sample was obtained in the same manner as in Example 4. The values ​​of the above formula (1) in the test sample are shown in Table 1.

[0296] <Example 8> 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. Otherwise, the test sample was obtained in the same manner as in Example 4. The values ​​of the above formula (1) in the test sample are shown in Table 1.

[0297] <Example 9> 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 coverslip was changed to 77.2 mm. Otherwise, the same procedure as in Example 1 was followed to obtain the test sample. The values ​​of the above formula (1) in the test sample are shown in Table 2.

[0298] <Example 10> The thickness d1 of the first adhesive layer was changed to 200 μm, and the same procedure as in Example 9 was followed to obtain the test sample. The values ​​of the above formula (1) in the test sample are shown in Table 2.

[0299] <Example 11> The thickness d1 of the first adhesive layer was changed to 300 μm, and the same procedure as in Example 9 was followed to obtain the test sample. The values ​​of the above formula (1) in the test sample are shown in Table 2.

[0300] <Example 12> The thickness d2 of the second adhesive layer was changed to 25 μm, and the same procedure as in Example 9 was followed to obtain the test sample. The values ​​of the above formula (1) in the test sample are shown in Table 2.

[0301] <Example 13> 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. Otherwise, the same procedure as in Example 9 was followed to obtain the test sample. The values ​​of the above formula (1) in the test sample are shown in Table 2.

[0302] <Example 14> 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. Otherwise, the same procedure as in Example 9 was followed to obtain the test sample. The values ​​of the above formula (1) in the test sample are shown in Table 2.

[0303] <Comparative Example 1> The thickness d1 of the first adhesive layer was changed to 100 μm, and the same procedure as in Example 1 was followed to obtain the test sample. The values ​​of the above formula (1) in the test sample are shown in Table 3.

[0304] <Comparative Example 2> The thickness d1 of the first adhesive layer was changed to 200 μm, and the same procedure as in Example 1 was followed to obtain the test sample. The values ​​of the above formula (1) in the test sample are shown in Table 3.

[0305] <Comparative Example 3> 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. Otherwise, the same procedure as in Example 1 was followed to obtain the test sample. The values ​​of the above formula (1) in the test sample are shown in Table 3.

[0306] <Comparative Example 4> The thickness d1 of the first adhesive layer was changed to 100 μm, and the test sample was obtained in the same manner as in Example 4. The values ​​of the above formula (1) in the test sample are shown in Table 3.

[0307] [evaluate] As shown in Tables 1 to 3, it is known that if the test sample satisfies the above equation (1), the adhesion rate of the optical laminate to the three-dimensional curved surface can be significantly improved.

[0308] Industrial availability The image display device manufactured through embodiments of the present invention can be used in various industrial products, and is particularly suitable for use in mobile phones (smartphones), laptops, furniture, etc.

Claims

1. An image display device comprising: Transparent components with three-dimensional curved surfaces; Optical laminates attached to the three-dimensional curved surface; and The image display panel located on the opposite side of the three-dimensional curved surface relative to the optical laminate. The optical laminate comprises: The first adhesive layer in contact with the three-dimensional curved surface; The polarizer is located on the opposite side of the three-dimensional curved surface relative to the first adhesive layer; and The second adhesive layer, located opposite the first adhesive layer to the polarizer, is in contact with the image display panel. Satisfy the following equation (1): R 2 x (d1+d2) / 1000 > 310... (1) In equation (1), R represents the radius of curvature of the three-dimensional 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 exceeds 150 μm and is 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 greater than 10 μm 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 device according to claim 1, wherein, The image display panel is curved along the three-dimensional surface. The radius of curvature of the image display panel is smaller than the radius of curvature of the three-dimensional surface.

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

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

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

11. The image display device according to claim 1, wherein, The optical laminate further comprises a first retardation film located between the polarizer and the first adhesive layer. 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 image display device according to claim 1, wherein, The optical laminate further comprises a second retardation film located between the second adhesive layer and the polarizer. 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, comprising, in sequence: The process of preparing an optical laminate that sequentially includes a polarizer and a second adhesive layer; The process of attaching the optical laminate to the image display panel via the second adhesive layer; and The process of attaching the optical laminate to the three-dimensional curved surface of the transparent component using a first adhesive layer. Satisfy the following equation (1): 2500>R 2 ×(d1+d2) / 1000>310···(1) In equation (1), R represents the radius of curvature of the three-dimensional 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 method for manufacturing an image display device, comprising the following steps: The process of preparing an optical laminate that sequentially includes a polarizer and a second adhesive layer; The process of attaching the optical laminate to the image display panel using the second adhesive layer; The process of attaching the optical laminate to the transparent component using a first adhesive layer; and The process of shaping the transparent component into a three-dimensional curved surface with the image display panel and the optical laminate attached to the transparent component. Satisfy the following equation (1): 2500>R 2 ×(d1+d2) / 1000>310···(1) In equation (1), R represents the radius of curvature of the three-dimensional 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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