Set of optical stacks

Abstract

To provide an optical laminate which enables a display system having stable optical characteristics even in a severe environment.SOLUTION: A set of optical laminates according to an embodiment of the present invention is a set of a first optical laminate and a second optical laminate, in which a variation (retardation variation XD) in the in-plane retardation (590) of the first optical laminate when placed in an atmosphere of 65 °C / 90% for 500 hours and a variation (retardation variation XL) in the in-plane retardation (590) of the second optical laminate when placed in an atmosphere of 65 °C / 90% for 500 hours satisfy the relationship of XD-XL ≤ 3nm.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an optical laminate set. [Background technology]

[0002] Image display devices, such as liquid crystal display devices and electroluminescence (EL) display devices (e.g., organic EL display devices), are rapidly becoming popular. In image display devices, optical components such as polarizing components and phase difference components are generally used to realize image display and improve the performance of the image display (see, for example, Patent Document 1).

[0003] In recent years, new applications for image display devices have been developed. For example, goggles with displays (VR goggles) for realizing virtual reality (VR) have begun to be commercialized. Since VR goggles are being considered for use in a variety of situations, they are required to be more stable in harsh environments such as high temperature and / or high humidity than optical laminates used in conventional image display devices. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2021-103286 Summary of the Invention [Problem to be solved by the invention]

[0005] A main object of the present invention is to provide an optical laminate that enables a display system with stable optical properties even under harsh environments. [Means for solving the problem]

[0006] 1. A set of optical laminates according to an embodiment of the present invention is a set of a first optical laminate and a second optical laminate, in which the change in in-plane retardation (590) of the first optical laminate when placed in a 65°C / 90% humidity environment for 500 hours (retardation change XD) and the change in in-plane retardation (590) of the second optical laminate when placed in a 65°C / 90% humidity environment for 500 hours (retardation change XL) satisfy the relationship |XD-XL|≦3 nm. 2. In the set of optical laminates described in 1 above, the first optical laminate may include three or more types of optical members. 3. In the set of optical laminates described in 2 above, the number of optical members in the second optical laminate may be smaller than the number of optical members in the first optical laminate. 4. In the set of optical laminates according to any one of 1 to 3 above, the first optical laminate and the second optical laminate may each include a pressure-sensitive adhesive layer. 5. In the set of optical laminates described in 4 above, the number of pressure-sensitive adhesive layers in the first optical laminate may be greater than the number of pressure-sensitive adhesive layers in the second optical laminate. 6. In the set of optical laminates according to 4 or 5 above, the first optical laminate and the second optical laminate may each include two or more types of pressure-sensitive adhesive layers. 7. In the set of optical laminates according to any one of 4 to 6 above, the first optical laminate may include two or more pressure-sensitive adhesive layers, and at least two of the pressure-sensitive adhesive layers may have different thicknesses. 8. In the set of optical laminates according to any one of 4 to 6 above, the second optical laminate may include two or more pressure-sensitive adhesive layers, and at least two of the pressure-sensitive adhesive layers may have different thicknesses. 9. In the set of optical laminates described in 7 above, the second optical laminate may include two or more pressure-sensitive adhesive layers, and at least two of the pressure-sensitive adhesive layers may have different thicknesses. 10. A method for controlling an in-plane retardation change X of an optical laminate under a high-humidity environment according to an embodiment of the present invention is a method for controlling an in-plane retardation change X of an optical laminate including a pressure-sensitive adhesive layer and an optical member under a high-humidity environment, the method comprising adjusting the type and / or thickness of the pressure-sensitive adhesive layer. [Effects of the Invention]

[0007] According to an embodiment of the present invention, it is possible to provide an optical laminate that enables a display system with stable optical properties even in a harsh environment. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a schematic diagram showing a general configuration of a display system including an optical laminate according to one embodiment of the present invention. [Figure 2A] 1 is a schematic cross-sectional view of a first optical stack according to one embodiment of the present invention. [Figure 2B] 1 is a schematic cross-sectional view of a first optical stack according to one embodiment of the present invention. [Figure 3A] FIG. 2 is a schematic cross-sectional view of a second optical stack according to one embodiment of the present invention. [Figure 3B] FIG. 2 is a schematic cross-sectional view of a second optical stack according to one embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments of the present invention will be described with reference to the drawings, but the present invention is not limited to these embodiments. Furthermore, in order to clarify the description, the drawings may show the width, thickness, shape, etc. of each part more schematically than in the embodiments, but these are merely examples and are not intended to limit the interpretation of the present invention. Furthermore, in this specification, the symbol "to" indicating a numerical range includes the upper and lower limits, and "(meth)acrylic" means "acrylic and / or methacrylic."

[0010] (Definition of terms and symbols) The definitions of terms and symbols used in this specification are as follows. (1) Refractive index (nx, ny, nz) "nx" is the refractive index in the direction in which the in-plane refractive index is greatest (i.e., the slow axis direction), "ny" is the refractive index in the direction perpendicular to the slow axis in the plane (i.e., the fast axis direction), and "nz" is the refractive index in the thickness direction. (2) In-plane phase difference (Re) "Re(λ)" is the in-plane retardation measured with light of wavelength λ nm at 23°C. For example, "Re(550)" is the in-plane retardation measured with light of wavelength 550 nm at 23°C. Re(λ) is calculated by the formula: Re(λ)=(nx-ny)×d, where d (nm) is the thickness of the layer (film). (3) Retardation in the thickness direction (Rth) "Rth(λ)" is the retardation in the thickness direction measured with light of wavelength λ nm at 23°C. For example, "Rth(550)" is the retardation in the thickness direction measured with light of wavelength 550 nm at 23°C. Rth(λ) is calculated by the formula: Rth(λ) = (nx - nz) × d, where d (nm) is the thickness of the layer (film). (4) Nz coefficient The Nz coefficient is calculated by Nz=Rth / Re. (5)Angle When an angle is referred to herein, the angle includes both clockwise and counterclockwise angles relative to a reference direction. Thus, for example, "45°" means 45° clockwise or counterclockwise. Furthermore, in this specification, "substantially parallel" includes angles within a range of 0°±10°, such as 0°±5°, preferably 0°±3°, and more preferably 0°±1°. "Substantially perpendicular" includes angles within a range of 90°±10°, such as 90°±5°, preferably 90°±3°, and more preferably 90°±1°.

[0011] A. Setting of optical laminates A set of optical laminates according to an embodiment of the present invention is a set of a first optical laminate and a second optical laminate, in which the change in in-plane retardation (590) of the first optical laminate when placed in a 65°C / 90% humidity environment for 500 hours (retardation change XD) and the change in in-plane retardation (590) of the second optical laminate when placed in a 65°C / 90% humidity environment for 500 hours (retardation change XL) satisfy the relationship |XD-XL|≦3 nm.

[0012] The optical laminate set can be applied to a display system (for example, goggles with a display). Fig. 1 is a schematic diagram showing an example of a display system including the optical laminate set.

[0013] As shown in FIG. 1 , the display system 2 includes a display element 12, a reflective polarizing element 14, a first lens unit 16, a half mirror 18, a first phase difference element 20, a second phase difference element 22, and a second lens unit 24. The reflective polarizing element 14 is disposed in front of the display surface 12′ side of the display element 12 and can reflect light emitted from the display element 12. The first lens unit 16 is disposed on the optical path between the display element 12 and the reflective polarizing element 14, and the half mirror 18 is disposed between the display element 12 and the first lens unit 16. The first phase difference element 20 is disposed on the optical path between the display element 12 and the half mirror 18, and the second phase difference element 22 is disposed on the optical path between the half mirror 18 and the reflective polarizing element 14. Although not shown, the display system 2 may further include an absorptive polarizing element between the reflective polarizing element 14 and the second lens unit 24.

[0014] The components arranged in front of the half mirror (in the illustrated example, the half mirror 18, the first lens section 16, the second phase difference member 22, the reflective polarizing member 14, and the second lens section 24) may be collectively referred to as the lens section (lens section 4).

[0015] The display element 12 is, for example, a liquid crystal display or an organic EL display, and has a display surface 12' for displaying an image. The light emitted from the display surface 12' passes through, for example, a polarizing member 10 that may be included in the display element 12, and is converted into a first linearly polarized light.

[0016] The first phase difference member 20 includes a first λ / 4 member that can convert first linearly polarized light incident on the first phase difference member 20 into first circularly polarized light. When the first phase difference member does not include any member other than the first λ / 4 member, the first phase difference member may correspond to the first λ / 4 member. In addition to the first λ / 4 member, the first phase difference member 20 may include a member whose refractive index characteristics satisfy the relationship nz>nx=ny (hereinafter also referred to as a "first positive C plate").

[0017] The half mirror 18 transmits the light emitted from the display element 12 and reflects the light reflected by the reflective polarizing member 14 back toward the reflective polarizing member 14. The half mirror 18 can be provided integrally with the first lens portion 16.

[0018] The second phase difference member 22 includes a second λ / 4 member that can transmit light reflected by the reflective polarizing member 14 and the half mirror 18 through the reflective polarizing member 14. When the second phase difference member does not include any member other than the second λ / 4 member, the second phase difference member may correspond to the second λ / 4 member. The second phase difference member 22 may be provided integrally with the first lens unit 16.

[0019] The first circularly polarized light emitted from the first λ / 4 element included in the first phase difference element 20 passes through the half mirror 18 and the first lens unit 16, and is converted into the second linearly polarized light by the second λ / 4 element included in the second phase difference element 22. The second linearly polarized light emitted from the second λ / 4 element is reflected toward the half mirror 18 without passing through the reflective polarizing element 14. At this time, the polarization direction of the second linearly polarized light incident on the reflective polarizing element 14 is the same as the reflection axis of the reflective polarizing element 14. Therefore, the second linearly polarized light incident on the reflective polarizing element 14 is reflected by the reflective polarizing element 14.

[0020] The second linearly polarized light reflected by the reflective polarizing element 14 is converted into second circularly polarized light by the second λ / 4 element included in the second phase difference element 22, and the second circularly polarized light output from the second λ / 4 element passes through the first lens unit 16 and is reflected by the half mirror 18. The second circularly polarized light reflected by the half mirror 18 passes through the first lens unit 16 and is converted into third linearly polarized light by the second λ / 4 element included in the second phase difference element 22. The third linearly polarized light is transmitted through the reflective polarizing element 14. At this time, the polarization direction of the third linearly polarized light incident on the reflective polarizing element 14 is the same as the transmission axis of the reflective polarizing element 14. Therefore, the third linearly polarized light incident on the reflective polarizing element 14 is transmitted through the reflective polarizing element 14.

[0021] The display system 2 may include an absorptive polarizing element (typically, an absorptive polarizing film) in front of the reflective polarizing element 14 (the side closer to the eyes). The reflection axis of the reflective polarizing element 14 and the absorption axis of the absorptive polarizing element may be arranged substantially parallel to each other, and the transmission axis of the reflective polarizing element and the transmission axis of the absorptive polarizing element may be arranged substantially parallel to each other. This allows the third linearly polarized light that has passed through the reflective polarizing element 14 to pass directly through the absorptive polarizing element. The reflective polarizing element and the absorptive polarizing element may be laminated together, for example, via an adhesive layer.

[0022] The light transmitted through the reflective polarizing member 14 passes through the second lens portion 24 and enters the eye 26 of the user.

[0023] For example, the absorption axis of the polarizing member 10 included in the display element 12 and the reflection axis of the reflective polarizing member 14 may be disposed approximately parallel to each other or approximately perpendicular to each other. The angle formed between the absorption axis of the polarizing member 10 included in the display element 12 and the slow axis of the first λ / 4 member included in the first retardation member 20 is, for example, 40° to 50°, or may be 42° to 48°, or may be approximately 45°. The angle formed between the absorption axis of the polarizing member 10 included in the display element 12 and the slow axis of the second λ / 4 member included in the second retardation member 22 is, for example, 40° to 50°, or may be 42° to 48°, or may be approximately 45°.

[0024] Typically, the first optical laminate may include a first retardation member 20. Therefore, the first optical laminate may be disposed on the optical path between the display element 12 and the half mirror 18. Furthermore, the second optical laminate may include a second retardation member 22. Therefore, the second optical laminate may be disposed on the optical path between the half mirror 18 and the reflective polarizing member 14. When the set of optical laminates is applied to the display system, the phase difference change XD and the phase difference change XL satisfy the relationship |XD-XL|≦3 nm, thereby suppressing the occurrence of ghosting in the display system even in a high-humidity environment. According to the embodiment of the present invention, even if the phase difference changes of the first optical laminate and the second optical laminate are large, the display characteristics can be improved as described above. Therefore, the design flexibility of the first optical laminate or the second optical laminate can be increased. For example, the thickness of the pressure-sensitive adhesive layer can be increased to improve the adhesiveness of the pressure-sensitive adhesive layer while preventing deterioration of the display characteristics.

[0025] The absolute value of the difference (|XD-XL|) between the change in in-plane retardation (590) of the first optical laminate after 500 hours in a 65°C / 90% humidity environment (retardation change XD) and the change in in-plane retardation (590) of the second optical laminate after 500 hours in a 65°C / 90% humidity environment (retardation change XL) is preferably 2.5 nm or less, more preferably 2.0 nm or less, even more preferably 1.5 nm or less, particularly preferably 1.0 nm or less, and most preferably 0.5 nm or less. Within such a range, the above-mentioned effects are significant. Note that the retardation changes XD and XL refer to the difference between the in-plane retardation (590) at room temperature and the in-plane retardation (590) after 500 hours in a high-humidity environment (65°C / 90% humidity environment) (in-plane retardation at high temperature - in-plane retardation at room temperature).

[0026] The absolute value of the change in in-plane retardation (590) of the first optical laminate (retardation change XD) is preferably 10 nm or less, more preferably 8 nm or less, and even more preferably 6 nm or less. The absolute value of the change in in-plane retardation (590) of the second optical laminate (retardation change XL) is preferably 10 nm or less, more preferably 8 nm or less, and even more preferably 6 nm or less.

[0027] In one embodiment, the first optical laminate and the second optical laminate include two or more optical members. The first optical laminate and the second optical laminate may include two or more types of optical members. The first optical laminate and the second optical laminate may include a pressure-sensitive adhesive layer. In each of the first optical laminate and the second optical laminate, the optical members may be laminated via a pressure-sensitive adhesive layer. In one embodiment, the phase difference change (the |XD-XL|) of the first optical laminate and the second optical laminate can be controlled by the number of layers, composition, thickness, etc. of the pressure-sensitive adhesive layer.

[0028] In one embodiment, the first optical laminate includes 3 or more, 4 or more, 5 or more, or 6 to 10 optical members. The first optical laminate may include 3 or more, 4 or more, 5 or more, or 6 to 10 optical members.

[0029] In one embodiment, the second optical laminate includes 3 or more, 4 or more, 5 or more, or 6 to 10 optical members. The second optical laminate may include 3 or more, 4 or more, 5 or more, or 6 to 10 optical members.

[0030] In one embodiment, the number of optical members in the second optical stack is less than the number of optical members in the first optical stack.

[0031] In one embodiment, the number of pressure-sensitive adhesive layers in the first optical laminate is 2 or more, 3 or more, 4 or more, or 5 to 9. The first optical laminate may include 2 or more, 3 or more, 4 or more, or 5 to 9 types of pressure-sensitive adhesive layers. In this specification, different types of pressure-sensitive adhesive layers refer to pressure-sensitive adhesive layers with different compositions. Therefore, for example, pressure-sensitive adhesive layers that have the same composition but different thicknesses are considered to be the same type of pressure-sensitive adhesive layer.

[0032] In one embodiment, the number of pressure-sensitive adhesive layers in the second optical laminate is 2 or more, 3 or more, 4 or more, or 5 to 9. The second optical laminate may include 2 or more, 3 or more, 4 or more, or 5 to 9 types of pressure-sensitive adhesive layers.

[0033] In one embodiment, the number of pressure-sensitive adhesive layers in the first optical laminate is greater than the number of pressure-sensitive adhesive layers in the second optical laminate.

[0034] In one embodiment, the first optical laminate includes two or more pressure-sensitive adhesive layers, and at least two of the pressure-sensitive adhesive layers have different thicknesses.

[0035] In one embodiment, the second optical laminate includes two or more pressure-sensitive adhesive layers, and at least two of the pressure-sensitive adhesive layers have different thicknesses.

[0036] Examples of optical members included in the optical laminate include an absorptive polarizing member, a reflective polarizing member, a phase difference member, etc. In this specification, the optical member refers to a member having optical properties (e.g., polarization, light refraction, light scattering, light reflectivity, light transparency, light absorption, light diffraction, optical rotation, etc.).

[0037] <First Optical Laminate> 2A and 2B are schematic cross-sectional views of a first optical laminate according to one embodiment of the present invention. The first optical laminate 100a shown in FIG. 2A includes, in this order, a first pressure-sensitive adhesive layer a1, a polarizing member 10, a second pressure-sensitive adhesive layer a2, a first retardation member 20, a third pressure-sensitive adhesive layer a3, and a protective member 30. Specifically, the polarizing member 10 and the first retardation member 20 are bonded together via the second pressure-sensitive adhesive layer a2, and the first retardation member 20 and the protective member 30 are bonded together via the third pressure-sensitive adhesive layer a3. The first pressure-sensitive adhesive layer a1 is a pressure-sensitive adhesive layer for bonding the first optical laminate 100a to an adjacent member (e.g., another member constituting display-equipped goggles), and its surface may be protected by a release liner until use.

[0038] (Adhesive layer) As described above, the first pressure-sensitive adhesive layer, the second pressure-sensitive adhesive layer and the third pressure-sensitive adhesive layer may be pressure-sensitive adhesive layers of the same type or different types.

[0039] The pressure-sensitive adhesive layer can be composed of any appropriate pressure-sensitive adhesive. Specific examples include acrylic pressure-sensitive adhesives, rubber pressure-sensitive adhesives, silicone pressure-sensitive adhesives, polyester pressure-sensitive adhesives, urethane pressure-sensitive adhesives, epoxy pressure-sensitive adhesives, and polyether pressure-sensitive adhesives. By adjusting the type, number, combination, and compounding ratio of monomers forming the base resin of the pressure-sensitive adhesive, as well as the compounding amount of cross-linking agent, reaction temperature, reaction time, etc., a pressure-sensitive adhesive having desired properties according to the purpose can be prepared. The base resin of the pressure-sensitive adhesive may be used alone or in combination of two or more types. An acrylic resin is preferably used as the base resin. Specifically, the pressure-sensitive adhesive layer is preferably composed of an acrylic pressure-sensitive adhesive.

[0040] For example, the pressure-sensitive adhesive layer can be formed by applying a pressure-sensitive adhesive composition containing a base resin, additives such as a crosslinking agent, and a solvent, followed by drying. The pressure-sensitive adhesive composition may be applied directly to the adherend, or may be applied to a separately prepared substrate such as a base film (e.g., a release liner). Drying is typically performed by heating.

[0041] The thickness of the pressure-sensitive adhesive layer is, for example, 1 μm to 100 μm, preferably 3 μm to 70 μm, more preferably 5 μm to 50 μm, even more preferably 10 μm to 40 μm, and particularly preferably 15 μm to 30 μm. In one embodiment, the retardation change (XD, XL) of the optical laminate can be controlled by adjusting the thickness of the pressure-sensitive adhesive layer. For example, the retardation change (XD, XL) can be reduced by making the pressure-sensitive adhesive layer thinner.

[0042] In one embodiment, the pressure-sensitive adhesive layer is formed to a thickness of more than 5 μm. By increasing the thickness of the pressure-sensitive adhesive layer, adhesion can be improved. In particular, increasing the thickness of a pressure-sensitive adhesive layer (e.g., a first pressure-sensitive adhesive layer) for bonding the optical laminate to an adjacent member (e.g., another member constituting display-equipped goggles) is advantageous in that peeling from the member can be prevented. Furthermore, by increasing the thickness of the pressure-sensitive adhesive layer, the influence of foreign matter on the adherend can be alleviated. In the set of optical laminates, adjusting the relationship between the phase difference change XD of the first optical laminate and the phase difference change XL of the second optical laminate is a requirement for improving display characteristics. Therefore, even if the pressure-sensitive adhesive layer is made thicker, the influence (e.g., the influence of an increase in the phase difference change value of the optical laminate alone) can be suppressed, thereby improving display characteristics.

[0043] The pressure-sensitive adhesive layer preferably has a storage modulus at 25°C of 0.01 MPa to 3 MPa, more preferably 0.05 MPa to 1 MPa, and even more preferably 0.1 MPa to 0.5 MPa. In one embodiment, the retardation change (XD, XL) of the optical laminate can be controlled by adjusting the modulus of elasticity of the pressure-sensitive adhesive layer. For example, the retardation change (XD, XL) can be reduced by increasing the modulus of elasticity of the pressure-sensitive adhesive layer. The storage modulus can be determined, for example, by dynamic viscoelasticity measurement using a dynamic viscoelasticity measurement device (Advanced Rheometric Expansion System (ARES), manufactured by Rheometric Scientific) (measurement conditions, for example, parallel plate (8.0 mmφ), torsion mode, frequency range 1 Hz).

[0044] The coefficient of linear expansion of the pressure-sensitive adhesive layer when heated from 60°C to 70°C is, for example, 6.5 × 10 -4 / ℃ or more 10.0×10 -4 / °C or less. In one embodiment, the change in retardation (XD, XL) of the optical laminate can be controlled by adjusting the linear expansion coefficient of the pressure-sensitive adhesive layer. For example, the change in retardation (XD, XL) can be reduced by reducing the linear expansion coefficient of the pressure-sensitive adhesive layer. The linear expansion coefficient is measured by TMA measurement. The TMA measurement can be performed under the following conditions. Measurement sample: 5mm square x 1mm Measurement equipment: SII Nanotechnology "TMA / SS6000" Measurement mode: Compression and expansion method Measurement load: 9.8mN Probe diameter: 3.5mm (compression expansion method) Temperature program: -60℃ → 210℃ → -70℃ → 200℃ ·Temperature rising / cooling rate: 10℃ / min Measurement atmosphere: N2 (flow rate: 200 ml / min)

[0045] In one embodiment, there is provided a method for controlling the in-plane retardation change X of an optical laminate including a pressure-sensitive adhesive layer and an optical member in a high-humidity environment, the method comprising adjusting the type and / or thickness of the pressure-sensitive adhesive layer. The high-humidity environment may be, for example, an environment with a temperature of 40°C to 95°C and a humidity of 80% to 100%. The in-plane retardation change X may be a retardation change at a wavelength of 550 nm. The types of pressure-sensitive adhesive layers can be distinguished by adjusting the type, number, combination, and compounding ratio of monomers forming the base resin of the pressure-sensitive adhesive, as well as the amount of crosslinking agent, reaction temperature, reaction time, etc. (resulting in the physical properties of the pressure-sensitive adhesive layer).

[0046] (polarizing component) The polarizing element 10 is typically an absorptive polarizing element including a resin film (sometimes referred to as an absorptive polarizing film) containing a dichroic material, and may further include a protective layer on one or both sides thereof, as necessary. The protective layer is typically attached to the absorptive polarizing film via any suitable adhesive layer. A typical example of the adhesive that forms the adhesive layer is an ultraviolet-curable adhesive.

[0047] The polarizing member (absorptive polarizing film) preferably has a crossed transmittance (Tc) of 0.5% or less, more preferably 0.1% or less, and even more preferably 0.05% or less. The polarizing member (absorptive polarizing film) has a single transmittance (Ts) of, for example, 41.0% to 45.0%, and preferably 42.0% or more. The polarizing member (absorptive polarizing film) has a degree of polarization (P) of, for example, 99.0% to 99.997%, and preferably 99.9% or more.

[0048] The crossed transmittance, single transmittance, and degree of polarization can be measured, for example, using an ultraviolet-visible spectrophotometer. The degree of polarization P can be calculated from the obtained Tp and Tc by measuring the single transmittance Ts, parallel transmittance Tp, and crossed transmittance Tc using an ultraviolet-visible spectrophotometer, using the following formula: Ts, Tp, and Tc are Y values ​​measured using a 2-degree visual field (C light source) according to JIS Z8701 and corrected for luminosity. Polarization degree P(%)={(Tp-Tc) / (Tp+Tc)} 1 / 2 ×100

[0049] The thickness of the absorptive polarizing film is, for example, 1 μm or more and 20 μm or less, or may be 2 μm or more and 15 μm or less, or may be 12 μm or less, or 10 μm or less, or 8 μm or less, or may be 5 μm or less.

[0050] The absorptive polarizing film may be made from a single layer of resin film or may be made from a laminate of two or more layers.

[0051] When fabricating from a single-layer resin film, an absorptive polarizing film can be obtained by dyeing a hydrophilic polymer film such as a polyvinyl alcohol (PVA) film, a partially formalized PVA film, or a partially saponified ethylene-vinyl acetate copolymer film with iodine or a dichroic substance such as a dichroic dye, stretching, etc. Among these, an absorptive polarizing film obtained by dyeing a PVA film with iodine and uniaxially stretching it is preferred.

[0052] The dyeing with iodine is carried out, for example, by immersing the PVA film in an aqueous iodine solution. The stretching ratio of the uniaxial stretching is preferably 3 to 7 times. The stretching may be carried out after the dyeing treatment or while dyeing. Alternatively, the stretching may be followed by dyeing. If necessary, the PVA film may be subjected to a swelling treatment, a crosslinking treatment, a washing treatment, a drying treatment, etc.

[0053] Examples of laminates produced using the two or more layer laminate include a laminate of a resin substrate and a PVA-based resin layer (PVA-based resin film) laminated on the resin substrate, or a laminate of a resin substrate and a PVA-based resin layer formed by coating on the resin substrate. An absorptive polarizing film obtained using a laminate of a resin substrate and a PVA-based resin layer formed by coating on the resin substrate can be produced, for example, by applying a PVA-based resin solution to the resin substrate and drying the resin substrate to form a PVA-based resin layer on the resin substrate, thereby obtaining a laminate of the resin substrate and the PVA-based resin layer; and then stretching and dyeing the laminate to convert the PVA-based resin layer into an absorptive polarizing film. In this embodiment, a polyvinyl alcohol-based resin layer containing a halide and a polyvinyl alcohol-based resin is preferably formed on one side of the resin substrate. The stretching typically involves immersing the laminate in an aqueous boric acid solution and stretching it. Furthermore, the stretching may further include, if necessary, in-air stretching of the laminate at an elevated temperature (e.g., 95°C or higher) before stretching in the aqueous boric acid solution. Additionally, in this embodiment, the laminate is preferably subjected to a drying shrinkage treatment by heating while being transported in the longitudinal direction, thereby shrinking the laminate by 2% or more in the width direction. Typically, the manufacturing method of this embodiment includes subjecting the laminate to an in-air auxiliary stretching treatment, a dyeing treatment, an underwater stretching treatment, and a drying shrinkage treatment, in this order. By introducing auxiliary stretching, it is possible to increase the crystallinity of PVA, even when PVA is coated on a thermoplastic resin, thereby achieving high optical properties. Furthermore, by simultaneously increasing the orientation of PVA in advance, problems such as a decrease in orientation or dissolution of PVA when immersed in water in the subsequent dyeing and stretching steps can be prevented, thereby achieving high optical properties. Furthermore, when the PVA-based resin layer is immersed in a liquid, the disordering of the orientation of polyvinyl alcohol molecules and the decrease in orientation can be suppressed compared to when the PVA-based resin layer does not contain a halide. This can improve the optical properties of an absorptive polarizing film obtained by immersing the laminate in a liquid through treatment steps such as dyeing and underwater stretching. Furthermore, the optical properties can be improved by shrinking the laminate in the width direction through drying shrinkage treatment.The obtained resin substrate / absorptive polarizing film laminate may be used as is (i.e., the resin substrate may be used as a protective layer for the absorptive polarizing film), or any suitable protective layer may be laminated depending on the purpose on the surface obtained by peeling the resin substrate from the resin substrate / absorptive polarizing film laminate, or on the surface opposite to the peeled surface. Details of such methods for producing absorptive polarizing films are described in, for example, JP 2012-73580 A and Japanese Patent No. 6470455 A. The entire disclosures of these publications are incorporated herein by reference.

[0054] The protective layer is formed of any suitable film that can be used as a protective layer for an absorptive polarizing film. Specific examples of materials that can be used as the main component of the film include cycloolefin (COP) resins such as polynorbornene resins, polyester resins such as polyethylene terephthalate (PET) resins, cellulose resins such as triacetyl cellulose (TAC), and transparent resins such as polycarbonate (PC), (meth)acrylic resins, polyvinyl alcohol resins, polyamides, polyimides, polyethersulfones, polysulfones, polystyrenes, polyolefins, and acetate resins. Other examples include thermosetting or ultraviolet-curable resins such as (meth)acrylic resins, urethane resins, (meth)acrylic urethane resins, epoxy resins, and silicone resins. Other examples include glassy polymers such as siloxane polymers. Polymer films described in JP 2001-343529 A (WO 01 / 37007) can also be used. Examples of materials for this film include resin compositions containing a thermoplastic resin with substituted or unsubstituted imide groups in its side chains and a thermoplastic resin with substituted or unsubstituted phenyl and nitrile groups in its side chains. Examples include a resin composition containing an alternating copolymer of isobutene and N-methylmaleimide and an acrylonitrile-styrene copolymer. The polymer film can be, for example, an extrusion molded product of the above resin composition. The resin film materials can be used alone or in combination.

[0055] The thickness of the protective layer is typically 100 μm or less, for example, 5 μm to 80 μm, preferably 10 μm to 50 μm, and more preferably 15 μm to 35 μm.

[0056] (First phase difference member) The first retardation member 20 includes a first λ / 4 member 20a. The first λ / 4 member 20a is arranged so that the angle between the absorption axis of the polarizing member 10 (absorptive polarizing film) and the slow axis of the first λ / 4 member 20a is preferably 40° to 50°, more preferably 42° to 48°, for example, approximately 45°.

[0057] As shown in FIG. 2B , the first phase difference member 20 may include, in addition to the first λ / 4 member 20a, a member (so-called positive C plate) 20b whose refractive index characteristics can exhibit the relationship nz>nx=ny. The first λ / 4 member 20a and the positive C plate 20b may be laminated via an adhesive layer b1. As shown in the example, it is preferable that the first λ / 4 member 20a is located closer to the polarizing member 10 than the positive C plate 20b, but this arrangement may be reversed. The adhesive layer b1 is typically a pressure-sensitive adhesive layer or an adhesive layer.

[0058] The in-plane retardation Re(550) of the first λ / 4 component 20a is, for example, 100 nm to 190 nm, or alternatively, 110 nm to 180 nm, 130 nm to 160 nm, or 135 nm to 155 nm. The first λ / 4 component preferably exhibits inverse dispersion wavelength characteristics in which the retardation value increases according to the wavelength of the measurement light. The Re(450) / Re(550) of the first λ / 4 component may be, for example, 0.75 or more and less than 1, or 0.8 or more and 0.95 or less.

[0059] The first λ / 4 member preferably exhibits a refractive index characteristic showing a relationship of nx > ny ≧ nz. Here, "ny = nz" includes not only the case where ny and nz are exactly equal but also the case where they are substantially equal. Therefore, within a range that does not impair the effects of the present invention, ny < nz may occur. The Nz coefficient of the first λ / 4 member is preferably 0.9 to 3, more preferably 0.9 to 2.5, still more preferably 0.9 to 1.5, and particularly preferably 0.9 to 1.3.

[0060] The first λ / 4 member is formed of any suitable material that can satisfy the above characteristics. The first λ / 4 member can be, for example, a stretched film of a resin film or an alignment and solidification layer of a liquid crystal compound.

[0061] Examples of the resin contained in the resin film include polycarbonate resins, polyester carbonate resins, polyester resins, polyvinyl acetal resins, polyarylate resins, cyclic olefin resins, cellulose resins, polyvinyl alcohol resins, polyamide resins, polyimide resins, polyether resins, polystyrene resins, acrylic resins, etc. These resins may be used alone or in combination. Examples of the combination method include blending and copolymerization. When the first λ / 4 member exhibits reverse dispersion wavelength characteristics, a resin film containing a polycarbonate resin or a polyester carbonate resin (hereinafter sometimes simply referred to as a polycarbonate resin) can be preferably used.

[0062] Any suitable polycarbonate-based resin can be used as the polycarbonate-based resin. For example, the polycarbonate-based resin contains structural units derived from a fluorene-based dihydroxy compound, structural units derived from an isosorbide-based dihydroxy compound, and structural units derived from at least one dihydroxy compound selected from the group consisting of alicyclic diols, alicyclic dimethanols, di-, tri-, or polyethylene glycols, and alkylene glycols or spiroglycols. Preferably, the polycarbonate-based resin contains structural units derived from a fluorene-based dihydroxy compound, structural units derived from an isosorbide-based dihydroxy compound, structural units derived from an alicyclic dimethanol, and / or structural units derived from di-, tri-, or polyethylene glycol; more preferably, it contains structural units derived from a fluorene-based dihydroxy compound, structural units derived from an isosorbide-based dihydroxy compound, and structural units derived from di-, tri-, or polyethylene glycol. The polycarbonate-based resin may contain structural units derived from other dihydroxy compounds as needed. Details of polycarbonate-based resins that can be suitably used for the first λ / 4 member and methods for forming the first λ / 4 member are described, for example, in JP 2014-10291 A, JP 2014-26266 A, JP 2015-212816 A, JP 2015-212817 A, and JP 2015-212818 A, and the descriptions of these publications are incorporated herein by reference.

[0063] The thickness of the first λ / 4 member made of a stretched resin film is, for example, 10 μm to 100 μm, preferably 10 μm to 70 μm, and more preferably 20 μm to 60 μm.

[0064] The above-mentioned liquid crystal compound alignment / solidification layer is a layer in which the liquid crystal compound is aligned in a predetermined direction within the layer and the alignment state is fixed. The term "alignment / solidification layer" encompasses an alignment / solidification layer obtained by curing a liquid crystal monomer, as described below. In the first λ / 4 member, typically, rod-shaped liquid crystal compounds are aligned in the slow axis direction of the first λ / 4 member (homogeneous alignment). Examples of rod-shaped liquid crystal compounds include liquid crystal polymers and liquid crystal monomers. The liquid crystal compound is preferably polymerizable. If the liquid crystal compound is polymerizable, the alignment state of the liquid crystal compound can be fixed by aligning the liquid crystal compound and then polymerizing it.

[0065] The alignment and solidification layer of the liquid crystal compound (liquid crystal alignment and solidification layer) can be formed by performing an alignment treatment on the surface of a predetermined substrate, applying a coating liquid containing a liquid crystal compound to the surface to align the liquid crystal compound in a direction corresponding to the alignment treatment, and fixing the alignment state. Any appropriate alignment treatment can be used as the alignment treatment. Specific examples include mechanical alignment treatment, physical alignment treatment, and chemical alignment treatment. Specific examples of mechanical alignment treatment include rubbing treatment and stretching treatment. Specific examples of physical alignment treatment include magnetic field alignment treatment and electric field alignment treatment. Specific examples of chemical alignment treatment include oblique vapor deposition and photoalignment treatment. Any appropriate treatment conditions can be used for the various alignment treatments depending on the purpose.

[0066] The alignment of liquid crystal compounds is achieved by treating them at a temperature at which they exhibit a liquid crystal phase depending on the type of liquid crystal compound. By performing such temperature treatment, the liquid crystal compounds assume a liquid crystal state and are aligned in accordance with the alignment treatment direction on the substrate surface.

[0067] In one embodiment, the alignment state is fixed by cooling the liquid crystal compound aligned as described above. When the liquid crystal compound is polymerizable or crosslinkable, the alignment state is fixed by subjecting the liquid crystal compound aligned as described above to a polymerization treatment or crosslinking treatment.

[0068] Any suitable liquid crystal polymer and / or liquid crystal monomer can be used as the liquid crystal compound. The liquid crystal polymer and the liquid crystal monomer can be used alone or in combination. Specific examples of liquid crystal compounds and methods for producing a liquid crystal alignment solidified layer are described in, for example, JP 2006-163343 A, JP 2006-178389 A, and WO 2018 / 123551 A. The descriptions in these publications are incorporated herein by reference.

[0069] The thickness of the first λ / 4 member formed of the liquid crystal alignment solidified layer is, for example, 1 μm to 10 μm, preferably 1 μm to 8 μm, more preferably 1 μm to 6 μm, and even more preferably 1 μm to 4 μm.

[0070] (protective material) The protective member 30 typically includes a substrate. The substrate can be made of any appropriate film. Examples of materials that form the main component of the film constituting the substrate include cellulose-based resins such as triacetyl cellulose (TAC), polyester-based, polyvinyl alcohol-based, polycarbonate-based, polyamide-based, polyimide-based, polyethersulfone-based, polysulfone-based, polystyrene-based, cycloolefin-based resins such as polynorbornene, polyolefin-based, (meth)acrylic-based, and acetate-based resins. The thickness of the substrate is preferably 5 μm to 80 μm, more preferably 10 μm to 40 μm, and even more preferably 15 μm to 35 μm.

[0071] The protective member preferably has a substrate and a surface treatment layer formed on the substrate. The surface treatment layer may be located on the outermost surface of the optical laminate 100a. The surface treatment layer may have any appropriate function. Examples of the surface treatment layer include a hard coat layer, an anti-reflection layer, an anti-sticking layer, and an anti-glare layer. The protective member may have two or more surface treatment layers.

[0072] The antireflection layer is provided to prevent reflection of external light, etc. Examples of the antireflection layer include a fluororesin layer, a resin layer containing nanoparticles (typically hollow nanoparticles, e.g., hollow nanosilica particles), and an antireflection layer having a nanostructure (e.g., a moth-eye structure). The thickness of the antireflection layer is preferably 0.05 μm to 1 μm. Examples of methods for forming the resin layer include a sol-gel method, a heat curing method using an isocyanate, and an ionizing radiation curing method (typically, a photocuring method) using a crosslinkable monomer (e.g., a polyfunctional acrylate) and a photopolymerization initiator.

[0073] The hard coat layer preferably has sufficient surface hardness, excellent mechanical strength, and excellent light transmittance. The hard coat layer can be formed from any appropriate resin. The hard coat layer is typically formed from an ultraviolet-curable resin. Examples of ultraviolet-curable resins include polyester-based, acrylic-based, urethane-based, amide-based, silicone-based, and epoxy-based resins. The thickness of the hard coat layer is, for example, 0.5 μm or more, preferably 1 μm or more, and, for example, 20 μm or less, preferably 15 μm or less.

[0074] (Positive C Plate) The thickness direction retardation Rth(550) of the positive C plate 20b is preferably −50 nm to −300 nm, more preferably −70 nm to −250 nm, even more preferably −90 nm to −200 nm, and particularly preferably −100 nm to −180 nm. Here, "nx=ny" encompasses not only the case where nx and ny are strictly equal, but also the case where nx and ny are substantially equal. The in-plane retardation Re(550) of the positive C plate is, for example, less than 10 nm.

[0075] The positive C plate can be formed of any appropriate material. The positive C plate is preferably composed of a film containing a liquid crystal material fixed in homeotropic alignment. The liquid crystal material (liquid crystal compound) that can be homeotropically aligned may be a liquid crystal monomer or a liquid crystal polymer. Specific examples of such liquid crystal compounds and methods for forming a positive C plate include the liquid crystal compounds and methods for forming a retardation layer described in paragraphs

[0020] to

[0028] of JP-A-2002-333642. In this case, the thickness of the positive C plate is preferably 0.5 μm to 5 μm.

[0076] <Second Optical Laminate> 3A and 3B are schematic cross-sectional views of a second optical laminate according to one embodiment of the present invention. The second optical laminate 200a shown in FIG. 3A includes, in this order, a fourth pressure-sensitive adhesive layer a4, a second phase difference member 22, a fifth pressure-sensitive adhesive layer a5, and a protective member 30. Specifically, the second phase difference member 22 and the protective member 30 are bonded together via the fifth pressure-sensitive adhesive layer a5. The fourth pressure-sensitive adhesive layer a4 is a pressure-sensitive adhesive layer for bonding the optical laminate 200a itself to an adjacent member (e.g., another member constituting display-equipped goggles), and its surface may be protected by a release liner until use.

[0077] Regarding the adhesive layer and the protective member, the description is as above. The second retardation member 22 includes a third λ / 4 member 22a. Regarding the third λ / 4 member, the same description as that of the first 4 / λ member can be applied. The first λ / 4 member and the third λ / 4 member may be members having the same configuration (e.g., forming material, thickness, optical characteristics, etc.), or may be members having different configurations. The in-plane retardation Re(550) of the third λ / 4 member is, for example, 100 nm to 190 nm, may be 110 nm to 180 nm, may be 130 nm to 160 nm, or may be 135 nm to 155 nm. The third λ / 4 member preferably exhibits an inverse dispersion wavelength characteristic in which the retardation value increases according to the wavelength of the measurement light. The third λ / 4 member preferably satisfies the relationship of Re(450) < Re(550) < Re(650). Re(450) / Re(550) of the third λ / 4 member is, for example, 0.75 or more and less than 1, and may be 0.8 or more and 0.95 or less.

[0078] As shown in FIG. 3B, the second retardation member 22 may include a member (so-called positive C-plate) 22b having a refractive index characteristic showing the relationship of nz > nx = ny in addition to the third λ / 4 member 22a. Regarding the positive C-plate, the description is as above. The third λ / 4 member 22a and the positive C-plate 22b are laminated via an adhesive layer b1.

Example

[0079] Hereinafter, the present invention will be specifically described by way of examples, but the present invention is not limited to these examples. Note that the thickness and the like are values measured by the following measurement methods. <Thickness> For a thickness of 10 μm or less, it was measured using a scanning electron microscope (manufactured by JEOL Ltd., product name "JSM-7100F"). For a thickness exceeding 10 μm, it was measured using a digital micrometer (manufactured by Anritsu Corporation, product name "KC-351C"). <In-plane retardation> Using "KOBRA-WPR" manufactured by Oji Scientific Instruments Co., Ltd., the in-plane retardation at 23°C was measured. [[ID=2l]]

[0080] [Manufacturing Example 1] (Formation of adhesive layers A and B) A four-neck flask equipped with a stirring blade, thermometer, nitrogen gas inlet tube, and condenser was charged with a monomer mixture containing 94.9 parts by weight of butyl acrylate, 5 parts by weight of acrylic acid, and 0.1 parts by weight of 2-hydroxyethyl acrylate. Furthermore, 0.3 parts by weight of dibenzoyl peroxide as a polymerization initiator was charged along with ethyl acetate for 100 parts by weight of this monomer mixture. Nitrogen gas was introduced into the flask with gentle stirring to replace the atmosphere with nitrogen. The temperature in the flask was maintained at 60°C, and the polymerization reaction was carried out for 7 hours. Ethyl acetate was then added to the resulting reaction solution to adjust the solids concentration to 30% by weight, producing an acrylic polymer solution with a weight-average molecular weight (Mw) of 2.2 million. An acrylic adhesive was prepared by blending 0.6 parts by weight of a trimethylolpropane / tolylene diisocyanate adduct (trade name: Coronate L, manufactured by Tosoh Corporation) and 0.075 parts by weight of a silane coupling agent (trade name: KBM403, manufactured by Shin-Etsu Chemical Co., Ltd.) with 100 parts by weight of the solid content of the obtained acrylic polymer solution. The obtained acrylic adhesive was coated on a substrate film, and the coating film on the obtained substrate film was dried in an oven to form an adhesive layer A having a thickness of 12 μm and an adhesive layer B having a thickness of 20 μm.

[0081] [Manufacturing Example 2] (Formation of adhesive layer C) A four-neck flask equipped with a stirring blade, thermometer, nitrogen gas inlet tube, and condenser was charged with a monomer mixture containing 92 parts by weight of butyl acrylate, 5 parts by weight of N-acryloylmorpholine, 2.9 parts by weight of acrylic acid, and 0.1 parts by weight of 2-hydroxyethyl acrylate. Furthermore, 0.1 parts by weight of 2,2'-azobisisobutyronitrile as a polymerization initiator and 100 parts by weight of ethyl acetate were charged to 100 parts by weight of this monomer mixture. Nitrogen gas was introduced into the flask with gentle stirring to replace the atmosphere with nitrogen. The temperature in the flask was maintained at around 55°C, and the polymerization reaction was carried out for 8 hours to prepare an acrylic polymer solution with a weight-average molecular weight (Mw) of 2,000,000. An acrylic adhesive was prepared by mixing 100 parts by weight of the solid content of the acrylic polymer solution with 0.15 parts by weight of dibenzoyl peroxide (1 minute half-life: 130°C) as a crosslinking agent and 0.6 parts by weight of a polyisocyanate crosslinking agent consisting of a trimethylolpropane adduct of tolylene diisocyanate (Coronate L, manufactured by Nippon Polyurethane Industry Co., Ltd.). The obtained acrylic pressure-sensitive adhesive was applied to a substrate film, and the resulting coating film on the substrate film was dried in an oven to form a pressure-sensitive adhesive layer C with a thickness of 5 μm.

[0082] [Manufacturing Example 3] (Fabrication of an absorption polarizing film) A long, amorphous isophthalic copolymerized polyethylene terephthalate film (thickness: 100 μm) having a Tg of about 75° C. was used as the thermoplastic resin substrate, and one side of the resin substrate was subjected to a corona treatment. A PVA aqueous solution (coating liquid) was prepared by dissolving 100 parts by weight of a PVA-based resin made by mixing polyvinyl alcohol (polymerization degree 4200, saponification degree 99.2 mol%) and acetoacetyl-modified PVA (manufactured by Mitsubishi Chemical Corporation, trade name "Gohsenex Z410") in a 9:1 ratio, to which 13 parts by weight of potassium iodide was added, in water. The above PVA aqueous solution was applied to the corona treated surface of the resin substrate and dried at 60° C. to form a PVA resin layer with a thickness of 13 μm, thereby producing a laminate. The resulting laminate was uniaxially stretched 2.4 times in the machine direction (longitudinal direction) in an oven at 130°C (auxiliary in-air stretching treatment). Next, the laminate was immersed in an insolubilizing bath (a boric acid aqueous solution obtained by mixing 4 parts by weight of boric acid with 100 parts by weight of water) at a liquid temperature of 40°C for 30 seconds (insolubilizing treatment). Next, the film was immersed in a dye bath (an aqueous iodine solution obtained by mixing iodine and potassium iodide in a weight ratio of 1:7 with 100 parts by weight of water) at a liquid temperature of 30°C for 60 seconds while adjusting the concentration so that the single transmittance (Ts) of the absorptive polarizing film finally obtained would have the desired value (dyeing treatment). Next, the sample was immersed in a crosslinking bath (a boric acid aqueous solution obtained by blending 3 parts by weight of potassium iodide and 5 parts by weight of boric acid with 100 parts by weight of water) at a liquid temperature of 40°C for 30 seconds (crosslinking treatment). The laminate was then immersed in a boric acid aqueous solution (boric acid concentration 4 wt %, potassium iodide concentration 5 wt %) at a liquid temperature of 70°C and uniaxially stretched in the longitudinal direction (longitudinal direction) between rolls with different peripheral speeds to a total stretch ratio of 5.5 times (underwater stretching treatment). Thereafter, the laminate was immersed in a cleaning bath (aqueous solution obtained by mixing 4 parts by weight of potassium iodide with 100 parts by weight of water) at a liquid temperature of 20° C. (cleaning treatment). Thereafter, the laminate was dried in an oven maintained at approximately 90°C and brought into contact with a heated SUS roll whose surface temperature was maintained at approximately 75°C (drying shrinkage treatment). The shrinkage rate in the width direction of the laminate due to the drying shrinkage treatment was 5.2%. In this way, an absorptive polarizing film having a thickness of about 5 μm was formed on the resin substrate.

[0083] (Fabrication of absorptive polarizing members) A 40 μm-thick acrylic film having a lactone ring structure was bonded as a protective layer to the surface of the obtained absorptive polarizing film (the surface opposite to the resin substrate) via a UV-curable adhesive. Specifically, the UV-curable adhesive was applied to a thickness of 2 μm, and the films were bonded using a roller. The adhesive was then cured by irradiating it with UV light from the acrylic film side. The resin substrate was then peeled off. In this way, an absorptive polarizing member 1 having an acrylic film / absorptive polarizing film configuration was obtained. The absorptive polarizing member 1 had a single transmittance (Ts) of 43.4% and a polarization degree of 99.993%.

[0084] [Manufacturing Example 4: Fabrication of λ / 4 components] Polymerization was carried out using a batch polymerization apparatus consisting of two vertical reactors equipped with stirring blades and reflux condensers controlled at 100° C. The polymerization mixture contained 29.60 parts by mass (0.046 mol) of bis[9-(2-phenoxycarbonylethyl)fluoren-9-yl]methane, 29.21 parts by mass (0.200 mol) of isosorbide (ISB), 42.28 parts by mass (0.139 mol) of spiroglycol (SPG), 63.77 parts by mass (0.298 mol) of diphenyl carbonate (DPC), and 1.19 × 10 calcium acetate monohydrate as a catalyst. -2 Part of mass (6.78×10 -5 (mol) was charged. After purging the reactor with nitrogen under reduced pressure, heating was performed using a heat transfer medium. Stirring was initiated when the internal temperature reached 100°C. Forty minutes after the start of the temperature increase, the internal temperature reached 220°C. This temperature was maintained while simultaneously reducing the pressure. 90 minutes after reaching 220°C, the pressure was reduced to 13.3 kPa. Phenol vapor by-produced during the polymerization reaction was introduced into a reflux condenser at 100°C, and the small amount of monomer components contained in the phenol vapor was returned to the reactor. Uncondensed phenol vapor was collected by introducing nitrogen into the first reactor and temporarily restoring the pressure to atmospheric pressure. The oligomerized reaction liquid in the first reactor was then transferred to the second reactor. Next, heating and depressurization of the second reactor were initiated, and the internal temperature reached 240°C and the pressure reached 0.2 kPa in 50 minutes. The polymerization was then allowed to proceed until the specified stirring power was reached. When the predetermined power was reached, nitrogen was introduced into the reactor to restore pressure, and the polyester carbonate resin produced was extruded into water, and the strands were cut to obtain pellets.

[0085] The resulting polyester carbonate resin pellets were vacuum-dried at 80°C for 5 hours and then processed into a 135µm-thick, long resin film using a film-forming device equipped with a single-screw extruder (manufactured by Toshiba Machine Co., Ltd., cylinder temperature setting: 250°C), a T-die (width: 200mm, temperature setting: 250°C), a chill roll (temperature setting: 120-130°C), and a winder. The resulting long resin film was stretched in the width direction at a stretching temperature of 143°C and a stretch ratio of 2.8 times. This resulted in a 47µm-thick stretched film (λ / 4 member 1). The Re(590) of the λ / 4 member 1 was 143nm, the Re(450) / Re(550) was 0.86, and the Nz coefficient was 1.12.

[0086] [Manufacturing Example 5: Preparation of protective member] The hard coat layer-forming material shown below was applied to an acrylic film having a lactone ring structure, and the applied layer was dried to form a hard coat layer with a thickness of 0.5 μm. Next, the antireflection layer-forming material shown below was applied to the surface of the hard coat layer and heated at 80° C. for 1 minute. After heating, the applied layer was irradiated with a high-pressure mercury lamp at an integrated light intensity of 300 mJ / cm. 2 The coating layer was cured by irradiating it with ultraviolet light of 1000 kJ / cm² to form an antireflection layer having a thickness of 0.1 µm, thereby obtaining a protective member 1 (thickness: 44 µm) having a structure of [acrylic film / hard coat layer / antireflection layer].

[0087] (Hard Coat Layer Forming Material) A hard coat layer-forming material was prepared by adding 0.5 wt% of a leveling agent to an acrylic resin raw material (manufactured by Dai Nippon Ink Co., Ltd., product name: GRANDIC PC1071) and further diluting with ethyl acetate to a solids concentration of 50 wt%. The leveling agent was a copolymer copolymerized in a molar ratio of dimethylsiloxane:hydroxypropylsiloxane:6-isocyanatehexylisocyanuric acid:aliphatic polyester = 6.3:1.0:2.2:1.0.

[0088] (Anti-reflection layer forming material) 100 parts by weight of a polyfunctional acrylate containing pentaerythritol triacrylate as the main component (manufactured by Osaka Organic Chemical Industry Co., Ltd., trade name "Viscoat #300", solid content 100 wt%), 100 parts by weight of hollow nanosilica particles (manufactured by JGC Catalysts and Chemicals Industries, Ltd., trade name "Sururia 5320", solid content 20 wt%, weight average particle diameter 75 nm), 100 parts by weight of solid nanosilica particles (manufactured by Nissan Chemical Industries, Ltd., trade name "MEK-2140Z-AC", solid content 30 wt%, weight average particle diameter 10 nm), 12 parts by weight of a fluorine-containing additive (manufactured by Shin-Etsu Chemical Co., Ltd., trade name "KY-1203", solid content 20 wt%), and 3 parts by weight of a photopolymerization initiator (manufactured by BASF, trade name "OMNIRAD907", solid content 100 wt%) were mixed. To this mixture was added a mixed solvent of tertiary butyl alcohol, methyl isobutyl ketone, and propylene glycol monomethyl ether acetate in a weight ratio of 60:25:15, and the mixture was stirred to give a total solids content of 4% by weight to prepare an anti-reflection layer-forming material.

[0089] [Manufacturing Example 6: Manufacturing of phase difference member (λ / 4 member / positive C plate)] A liquid crystal coating solution was prepared by dissolving 20 parts by mass of a side-chain liquid crystal polymer represented by the following chemical formula (1) (the numbers 65 and 35 in the formula indicate the mole percentages of the monomer units, and are conveniently represented as a block polymer: weight-average molecular weight 5000), 80 parts by mass of a polymerizable liquid crystal exhibiting a nematic liquid crystal phase (manufactured by BASF: trade name Paliocolor LC242), and 5 parts by mass of a photopolymerization initiator (manufactured by Ciba Specialty Chemicals: trade name Irgacure 907) in 200 parts by mass of cyclopentanone. [ka] The coating liquid was then applied to a substrate film (norbornene-based resin film: manufactured by Nippon Zeon Corporation, trade name "Zeonex") using a bar coater, and the liquid crystal was aligned by heating and drying at 80°C for 4 minutes. The liquid crystal layer was irradiated with ultraviolet light to harden it, forming a 4 μm-thick retardation member on the substrate. The retardation member thus obtained had a refractive index of nz > nx = ny. The retardation Rth(590) in the thickness direction of the retardation member (positive C plate) was 80 nm. This retardation member (positive C plate) and the λ / 4 member 1 produced in Production Example 4 were laminated together via an adhesive to obtain a retardation member A.

[0090] [Example 1] An adhesive layer B (thickness: 20 μm) was attached to one surface of the absorptive polarizing member 1, and an adhesive layer A (thickness: 12 μm) was attached to the other surface, and a retardation member A was attached thereon so that the λ / 4 member 1 and the absorptive polarizing member 1 faced each other. At this time, the absorptive polarizing member 1 was positioned so that the absorption axis of the absorptive polarizing member 1 and the slow axis of the λ / 4 member 1 formed an angle of 45°. Next, another pressure-sensitive adhesive layer A (thickness: 12 μm) was placed on the surface of the λ / 4 member 1, and the protective member 1 was attached thereon. At this time, the acrylic film side surface of the protective member 1 was attached to the retardation member A side (in other words, the surface treatment layer was attached to the outermost surface). In this way, a first optical laminate A was obtained having a structure of [adhesive layer B / absorptive polarizing member 1 / adhesive layer A / phase difference member A (positive C plate / λ / 4 member 1) / adhesive layer A / protective member 1]. An adhesive layer A (thickness: 12 μm) was placed on one surface (the surface on the positive C plate side) of the retardation member A. Furthermore, the protective member 1 was attached to the other surface of the retardation member A via the adhesive layer A (thickness: 12 μm). At this time, the protective member 1 was attached so that the acrylic film side surface faced the retardation member A side (in other words, so that the surface treatment layer became the outermost surface). In this manner, a second optical laminate A having a structure of [pressure-sensitive adhesive layer B / retardation member A (positive C plate / λ / 4 member 1) / pressure-sensitive adhesive layer A / protective member 1] was obtained. (evaluation) The change in retardation of the first optical laminate A and the second optical laminate A was measured by the following method. The retardation value at a predetermined wavelength was measured at 23°C using a retardation measurement device (Oji Scientific Instruments, product name "KOBRA-HBPR"). The first optical laminate A and second optical laminate A attached to glass were placed in a high-temperature, high-humidity environment (65°C, 90%) for 500 hours, then removed and the retardation value was measured in the same manner using the retardation measurement device. The retardation values ​​before and after being placed in the high-temperature, high-humidity environment were compared to calculate the change in retardation (after placement - before placement). The results are shown in Table 1.

[0091] [Example 2] In the same manner as in Example 1, a first optical laminate A was obtained. An adhesive layer A (thickness: 12 μm) was placed on one surface (the surface on the positive C plate side) of the retardation member A. Furthermore, a protective member 1 was attached to the other surface of the retardation member A via an adhesive layer C (thickness: 5 μm). At this time, the protective member 1 was attached so that the acrylic film side surface faced the retardation member A side (in other words, so that the surface treatment layer became the outermost surface). In this manner, a second optical laminate B having a structure of [adhesive layer A / retardation member A (positive C plate / λ / 4 member 1) / adhesive layer C / protective member 1] was obtained. (evaluation) The first optical laminate A and the second optical laminate B were used to prepare a sample similar to that in Example 1, and the sample was subjected to the same evaluation as in Example 1. The results are shown in Table 1.

[0092] [Example 3] In the same manner as in Example 1, a first optical laminate A was obtained. A second optical laminate C was obtained in the same manner as in Example 1, except that the thickness of the pressure-sensitive adhesive layer A was set to 20 μm. (evaluation) The first optical laminate A and the second optical laminate C were used to prepare a sample similar to that in Example 1, and the sample was subjected to the same evaluation as in Example 1. The results are shown in Table 1.

[0093] [Comparative Example 1] An adhesive layer B (thickness: 20 μm) was attached to one surface of the absorptive polarizing member 1, and an adhesive layer C (thickness: 5 μm) was attached to the other surface, and then a retardation member A was attached thereon so that the λ / 4 member 1 and the absorptive polarizing member 1 faced each other. At this time, the absorptive polarizing member 1 was positioned so that the absorption axis of the absorptive polarizing member 1 and the slow axis of the λ / 4 member 1 formed an angle of 45°. Next, the pressure-sensitive adhesive layer A (thickness: 12 μm) was placed on the surface of the λ / 4 member 1, and the protective member 1 was attached thereon. At this time, the protective member 1 was attached so that the acrylic film side surface faced the retardation member A side (in other words, so that the surface treatment layer became the outermost surface). In this way, a first optical laminate B was obtained having a structure of [adhesive layer B / absorptive polarizing member 1 / adhesive layer C / phase difference member A (positive C plate / λ / 4 member 1) / adhesive layer A / protective member 1]. An adhesive layer C (thickness: 5 μm) was placed on one surface (the surface on the positive C plate side) of the retardation member A. Furthermore, a protective member 1 was attached to the other surface of the retardation member A via an adhesive layer A (thickness: 12 μm). At this time, the protective member 1 was attached so that the acrylic film side surface faced the retardation member A side (in other words, so that the surface treatment layer became the outermost surface). In this manner, a second optical laminate D having a structure of [adhesive layer C / retardation member A (positive C plate / λ / 4 member 1) / adhesive layer A / protective member 1] was obtained. (evaluation) The first optical laminate B and the second optical laminate D were used to prepare a sample similar to that in Example 1, and the sample was subjected to the same evaluation as in Example 1. The results are shown in Table 1.

[0094] Comparative Example 2 In the same manner as in Example 1, a first optical laminate A was obtained. An adhesive layer C (5 μm thick) was placed on one surface (the surface on the positive C plate side) of the retardation member A. Furthermore, the protective member 1 was attached to the other surface of the retardation member A via the adhesive layer C (5 μm thick). At this time, the protective member 1 was attached so that the acrylic film side surface faced the retardation member A side (in other words, so that the surface treatment layer became the outermost surface). In this manner, a second optical laminate E having a structure of [pressure-sensitive adhesive layer C / retardation member A (positive C plate / λ / 4 member 1) / pressure-sensitive adhesive layer C / protective member 1] was obtained. (evaluation) The first optical laminate A and the second optical laminate E were used to prepare a sample similar to that in Example 1, and the sample was subjected to the same evaluation as in Example 1. The results are shown in Table 1.

[0095] [Table 1]

[0096] As shown in Table 1, in the examples, a set of optical laminates was obtained in which the difference between the change in in-plane retardation of the first optical laminate and the change in in-plane retardation of the second optical laminate was small. By using these optical laminates, a display system can be obtained in which the optical properties are stable even in harsh environments and the occurrence of ghosting is suppressed. [Industrial Applicability]

[0097] The optical laminate according to the embodiment of the present invention can be used, for example, in the manufacture of goggles with a display, such as VR goggles. [Explanation of symbols]

[0098] 2. Display System 4 Lens section 10 Polarizing element 12 Display element 14 Reflective polarizing element 16 First lens part 18 Half Mirror 20 First phase difference member 22 Second phase difference member 24 Second lens section

Claims

1. A set of a first optical laminate and a second optical laminate, wherein a change in in-plane retardation (590) of the first optical laminate when placed in an environment of 65°C / 90% humidity for 500 hours (retardation change XD) and a change in in-plane retardation (590) of the second optical laminate when placed in an environment of 65°C / 90% humidity for 500 hours (retardation change XL) satisfy the relationship |XD-XL|≦3 nm.

2. The set of optical laminates according to claim 1 , wherein the first optical laminate comprises three or more optical members.

3. The set of optical stacks according to claim 2 , wherein the number of optical elements in the second optical stack is less than the number of optical elements in the first optical stack.

4. The set of optical laminates according to claim 1 , wherein the first optical laminate and the second optical laminate each include a pressure-sensitive adhesive layer.

5. The set of optical laminates according to claim 4 , wherein the number of pressure-sensitive adhesive layers in the first optical laminate is greater than the number of pressure-sensitive adhesive layers in the second optical laminate.

6. The set of optical laminates according to claim 4 , wherein the first optical laminate and the second optical laminate each include two or more types of pressure-sensitive adhesive layers.

7. The set of optical laminates according to claim 4 , wherein the first optical laminate includes two or more pressure-sensitive adhesive layers, and at least two of the pressure-sensitive adhesive layers have different thicknesses.

8. The set of optical laminates according to claim 4 , wherein the second optical laminate includes two or more pressure-sensitive adhesive layers, and at least two of the pressure-sensitive adhesive layers have different thicknesses.

9. The set of optical laminates according to claim 7 , wherein the second optical laminate includes two or more pressure-sensitive adhesive layers, and at least two of the pressure-sensitive adhesive layers have different thicknesses.

10. A method for controlling an in-plane retardation change X of an optical laminate comprising a pressure-sensitive adhesive layer and an optical member in a high-humidity environment, the method comprising adjusting the type and / or thickness of the pressure-sensitive adhesive layer.

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