Optical laminate, method for manufacturing optical laminate, and optical information transmission device

Abstract

An optical laminate (10) includes an optical substrate (1), a (thio)urethane optical resin layer (2) on at least one side of the optical substrate 1, and an adhesive layer (3) between the optical substrate (1) and the (thio)urethane optical resin layer (2), wherein the adhesive layer (3) has a glass transition temperature of 70°C or less.

Description

Optical laminate, method for manufacturing optical laminate, and optical information transmission device

[0001] The present invention relates to an optical laminate, a method for manufacturing an optical laminate, and an optical information transmission device.

[0002] In recent years, there has been an increasing demand for resin materials in the field of optical devices due to reasons such as weight reduction and improved impact resistance. For example, the use of resin materials is required for optical devices that are worn on the human body when used, such as wearable devices.

[0003] Patent Document 1 discloses a light-weight optical element that contains an organic polymer and has an area of ​​1 mm ２ or more, and the area is 1 mm ２ The document discloses an optical member including a surface A, the flatness of which is measured by a non-contact optical flatness meter and is 80 μm or less.

[0004] International Publication No. 2020 / 170801

[0005] The present invention provides an optical laminate comprising an optical substrate and a (thio)urethane-based optical resin layer, which can suppress warping.

[0006] That is, according to the present invention, there are provided an optical laminate, a method for manufacturing an optical laminate, and an optical information transmission device as shown below. 1. An optical laminate comprising: an optical substrate; a (thio)urethane-based optical resin layer on at least one surface of the optical substrate; and an adhesive layer between the optical substrate and the (thio)urethane-based optical resin layer, wherein the adhesive layer has a glass transition temperature of 70°C or lower. 2. The optical laminate according to 1., wherein the loss modulus of the adhesive layer is 0.001 GPa or higher and 1.5 GPa or lower, measured in a tensile measurement mode at a temperature of 25°C and a measurement frequency of 1 Hz. 3. The optical laminate according to 1. or 2., wherein the thickness of the adhesive layer is 0.5 μm or higher and 1000 μm or lower. 4. The density D of the adhesive layer before curing, measured in accordance with JIS K-5600-2-4:2014, is ０ and density after hardening D １3. The optical laminate according to any one of 1. to 3., wherein the curing shrinkage obtained by the following formula (1) is 10% or less. Curing shrinkage (%)=(D １ -D ０ ) / D ０ (1) 5. The optical laminate according to any one of 1. to 4., wherein the refractive index of the adhesive layer at a temperature of 25°C and a wavelength of 587.6 nm in accordance with JIS K-0062:1992 is 1.47 or more. 6. The optical laminate according to any one of 1. to 5., wherein the adhesive layer contains one or more resins selected from the group consisting of (meth)acrylic resins and epoxy resins. 7. The optical laminate according to any one of 1. to 6., wherein the adhesive layer comprises a cured product of an adhesive resin composition, and the adhesive resin composition is a photocurable resin composition or a thermosetting resin composition. 8. The optical laminate according to any one of 1. to 7., wherein the thickness of the (thio)urethane optical resin layer is 2.0 mm or less. 9. The optical laminate according to 1. to 8., wherein the refractive index of the (thio)urethane optical resin layer at a temperature of 25°C and a wavelength of 587.6 nm in accordance with JIS K-0062:1992 is 1.47 or more. 10. The optical laminate according to any one of 1. to 9., wherein the optical substrate comprises one or more types selected from the group consisting of a glass substrate and an optical crystal substrate. 11. The optical laminate according to any one of 1. to 10., wherein the refractive index of the optical substrate at a temperature of 25°C and a wavelength of 587.6 nm in accordance with JIS K-0062:1992 is 1.47 or more. 12. The optical laminate according to any one of 1. to 11., further comprising a transparent inorganic layer between the optical substrate and the adhesive layer. 13. The optical laminate according to any one of 1. to 12., further comprising a coupling agent layer between the optical substrate and the adhesive layer. 14. The amount of warpage F of the surface A on the (thio)urethane-based optical resin layer side of the optical laminate ＡThe optical laminate according to any one of 1. to 13., wherein the thickness of the optical laminate is 350 μm or less. 15. The optical laminate according to any one of 1. to 14., wherein the (thio)urethane-based optical resin layer does not peel off from the optical substrate when the optical laminate is left standing for 360 hours in an environment at a temperature of 60° C. and a humidity of 90%. 16. The optical laminate according to any one of 1. to 15., wherein the refractive index of the optical laminate at a temperature of 25° C. and a wavelength of 587.6 nm in accordance with JIS K-0062:1992 is 1.47 or more. 17. The optical laminate according to any one of 1. to 16., which can be used in a wearable device. 18. 19. A method for producing an optical laminate, comprising: step (A) of preparing a laminate including an optical substrate, a (thio)urethane-based optical resin layer on at least one surface of the optical substrate, and an uncured or semi-cured adhesive layer between the optical substrate and the (thio)urethane-based optical resin layer; and step (B) of curing the uncured or semi-cured adhesive layer to obtain an optical laminate. 19. A method for producing an optical laminate according to item 18, further comprising step (C) of placing the laminate in a reduced pressure environment before step (B). 20. An optical information transmission device comprising: a light irradiation unit; and the optical laminate according to any one of items 1. to 17.

[0007] According to the present invention, it is possible to provide an optical laminate comprising an optical substrate and a (thio)urethane-based optical resin layer, which can suppress warping.

[0008] 1 is a cross-sectional view schematically showing an example of an optical laminate according to an embodiment of the present invention; 2 is a cross-sectional view schematically showing an example of an optical information transmission device according to an embodiment of the present invention;

[0009] The present invention will be described below based on the embodiments. When numerical ranges are described in stages, the upper and lower limits of each numerical range can be combined in any way.

[0010] [Optical Laminate] The optical laminate of this embodiment will be described in detail below.

[0011] The optical laminate of this embodiment will be described with reference to Fig. 1. The optical laminate 10 of this embodiment includes an optical substrate 1, a (thio)urethane-based optical resin layer 2 on at least one surface of the optical substrate 1, and an adhesive layer 3 between the optical substrate 1 and the (thio)urethane-based optical resin layer 2, and the glass transition temperature of the adhesive layer 3 is 70°C or lower.

[0012] Although the mechanism by which the optical laminate of this embodiment solves the above-mentioned problems is not clear, it is presumed that the above-mentioned problems are solved by the following mechanism. First, as a premise, due to the difference in linear expansion coefficient between the optical substrate and the (thio)urethane-based optical resin layer, the optical laminate is prone to distortion, which in turn makes it prone to warping. In the optical laminate of this embodiment, when distortion is applied to the optical laminate, the adhesive layer relieves stress, which is thought to suppress the occurrence of warping.

[0013] <Adhesive Layer> The adhesive layer of the optical laminate of this embodiment will be described below.

[0014] The glass transition temperature of the adhesive layer is, from the viewpoint of further suppressing warping of the optical laminate and suppressing peeling of the optical laminate, preferably 65°C or lower, more preferably 60°C or lower, even more preferably 55°C or lower, even more preferably 50°C or lower, and even more preferably 45°C or lower, and from the viewpoint of further suppressing warping of the optical laminate and suppressing peeling of the optical laminate in a high temperature environment and / or a high humidity environment, preferably -20°C or higher, more preferably -10°C or higher, even more preferably 0°C or higher, even more preferably 10°C or higher, even more preferably 15°C or higher, and even more preferably 20°C or higher.

[0015] From the viewpoint of further suppressing warping of the optical laminate and suppressing peeling of the optical laminate, the glass transition temperature of the adhesive layer is preferably −20° C. or higher and 70° C. or lower, more preferably −10° C. or higher and 65° C. or lower, even more preferably 0° C. or higher and 60° C. or lower, even more preferably 10° C. or higher and 55° C. or lower, even more preferably 15° C. or higher and 50° C. or lower, and even more preferably 20° C. or higher and 45° C. or lower.

[0016] The glass transition temperature of the adhesive layer can be measured by dynamic mechanical analysis (DMA). Specifically, it can be measured under the following <measurement conditions>. <Measurement conditions> Apparatus: Dynamic mechanical analysis apparatus Sample shape: Width 10 mm × Thickness 0.1 mm × Length 20 mm Heating rate: 5°C / min Measurement mode: Tension

[0017] The glass transition temperature of the adhesive layer can be adjusted by adjusting the composition of the adhesive layer, for example, by adjusting the ratio of high molecular weight components to low molecular weight components (e.g., additives, curing agents, etc.) in the adhesive layer, or by adjusting the crosslink density of the adhesive layer.

[0018] The loss modulus of the adhesive layer, measured in tension at a temperature of 25°C and a measurement frequency of 1 Hz, is preferably 0.001 GPa or more, more preferably 0.01 GPa or more, and even more preferably 0.03 GPa or more, from the viewpoint of further suppressing warping of the optical laminate and suppressing peeling of the optical laminate, and is preferably 1.5 GPa or less, more preferably 1.3 GPa or less, even more preferably 1.1 GPa or less, even more preferably 0.9 GPa or less, even more preferably 0.7 GPa or less, even more preferably 0.5 GPa or less, and even more preferably 0.3 GPa or less, from the viewpoint of further suppressing warping of the optical laminate and suppressing peeling of the optical laminate.

[0019] From the viewpoint of further suppressing warping of the optical laminate and suppressing peeling of the optical laminate, the loss modulus of the adhesive layer measured under conditions of a tensile measurement mode, a temperature of 25°C, and a measurement frequency of 1 Hz is preferably 0.001 GPa or more and 1.5 GPa or less, more preferably 0.01 GPa or more and 1.3 GPa or less, even more preferably 0.03 GPa or more and 1.1 GPa or less, even more preferably 0.03 GPa or more and 0.9 GPa or less, even more preferably 0.03 GPa or more and 0.7 GPa or less, even more preferably 0.03 GPa or more and 0.5 GPa or less, and even more preferably 0.03 GPa or more and 0.3 GPa or less.

[0020] The loss modulus of the adhesive layer can be measured by dynamic mechanical analysis (DMA). Specifically, it can be measured under the following measurement conditions. Measurement conditions: Apparatus: Dynamic mechanical analysis apparatus Sample shape: Width 10 mm x Thickness 0.1 mm x Length 20 mm Temperature: 25°C Measurement mode: Tension

[0021] The loss modulus of the adhesive layer can be adjusted by adjusting the composition of the adhesive layer, for example, by adjusting the ratio of high molecular weight components to low molecular weight components in the adhesive layer or by adjusting the crosslink density of the adhesive layer.

[0022] The thickness of the adhesive layer is preferably 0.5 μm or more, more preferably 1 μm or more, even more preferably 5 μm or more, even more preferably 10 μm or more, and even more preferably 15 μm or more, from the viewpoint of further suppressing warping of the optical laminate and suppressing peeling of the optical laminate, and is preferably 1000 μm or less, more preferably 500 μm or less, even more preferably 200 μm or less, even more preferably 100 μm or less, even more preferably 80 μm or less, and even more preferably 60 μm or less, from the viewpoint of reducing the thickness of the entire optical laminate.

[0023] From the viewpoint of further suppressing warping of the optical laminate while reducing the overall thickness of the optical laminate and suppressing peeling of the optical laminate, the thickness of the adhesive layer is preferably 0.5 μm or more and 1000 μm or less, more preferably 1 μm or more and 500 μm or less, even more preferably 5 μm or more and 200 μm or less, even more preferably 10 μm or more and 100 μm or less, even more preferably 15 μm or more and 80 μm or less, and even more preferably 15 μm or more and 60 μm or less.

[0024] Density D of the adhesive layer before curing measured in accordance with JIS K-5600-2-4:2014 ０ and density after hardening D １Therefore, the cure shrinkage obtained by the following formula (1) is preferably 10% or less, more preferably 9% or less, and even more preferably 8% or less, from the viewpoint of further suppressing warping of the optical laminate and suppressing peeling of the optical laminate, and may be, for example, 0.01% or more, 0.1% or more, or 1% or more. Cure shrinkage (%)=(D １ -D ０ ) / D ０ (1)

[0025] The cure shrinkage of the adhesive layer can be adjusted by adjusting the composition of the adhesive layer, for example, by adjusting the ratio of high molecular weight components to low molecular weight components in the adhesive layer or by adjusting the crosslink density of the adhesive layer.

[0026] The refractive index of the adhesive layer at a temperature of 25°C and a wavelength of 587.6 nm according to JIS K-0062:1992 is, from the viewpoint of improving the optical properties of the optical laminate, preferably 1.47 or more, more preferably 1.49 or more, even more preferably 1.51 or more, and still more preferably 1.53 or more, and may be, for example, 1.90 or less, 1.80 or less, or 1.70 or less.

[0027] The linear expansion coefficient of the adhesive layer measured under the following <Measurement Conditions> is preferably 200×10 from the viewpoint of further suppressing warping of the optical laminate and suppressing peeling of the optical laminate. －６ / °C or less, more preferably 150 x 10 －６ / °C or less, and from the viewpoint of further suppressing warping of the optical laminate and suppressing peeling of the optical laminate, it is better that the linear expansion coefficient with respect to the optical substrate is small. Therefore, it is preferably 2 × 10 －６ / °C or more, more preferably 4 x 10 －６ / °C or more, more preferably 6 × 10 －６ / °C or more, more preferably 8 x 10 －６ / °C or more. <Measurement conditions> Measurement mode: TMA compression mode Test load: 50 mN Heating rate: 5°C / min Test temperature range: 0 to 200°C Measurement atmosphere: nitrogen (100 ml / min)

[0028] The adhesive layer preferably contains one or more resins selected from the group consisting of (meth)acrylic resins and epoxy resins, and more preferably contains a (meth)acrylic resin.

[0029] The adhesive layer may further contain a known adhesive. Examples of known adhesives include laminating adhesives composed of organic titanium resins, polyethyleneimine resins, urethane resins, polyester resins, oxazoline group-containing resins, modified silicone resins, alkyl titanates, polyester polybutadienes, etc., as well as one-component and two-component polyols and polyisocyanates, water-based urethanes, ionomers, etc. Alternatively, aqueous adhesives containing acrylic resins, vinyl acetate resins, urethane resins, polyester resins, etc. as their main raw materials may be used. Furthermore, other additives such as curing agents and silane coupling agents may be added to the adhesive depending on the application of the gas barrier laminate.

[0030] The adhesive layer is preferably made of a cured product of an adhesive resin composition, and the adhesive resin composition is a photocurable resin composition or a thermosetting resin composition, and more preferably made of a cured product of an adhesive resin composition, and the adhesive resin composition is a photocurable resin composition.

[0031] The viscosity of the adhesive resin composition, measured using a cone-plate viscometer (manufactured by Brookfield, model name: DV2T) and a CPA-40G cone spindle (angle: 0.8°, radius: 24 mm, sample amount: 0.5 mL, shear rate: 7.5 N / s) at a temperature of 25°C, is preferably 50 mPa·s or more, more preferably 100 mPa·s or more, even more preferably 200 mPa·s or more, even more preferably 300 mPa·s or more, even more preferably 400 mPa·s or more, and preferably 5000 mPa·s or less, more preferably 2000 mPa·s or less, even more preferably 1000 mPa·s or less, even more preferably 800 mPa·s or less.

[0032] <(Thio)urethane-Based Optical Resin Layer> The (thio)urethane-based optical resin layer of this embodiment will be described below.

[0033] The (thio)urethane-based optical resin layer contains a (thio)urethane-based resin. The (thio)urethane-based resin can be obtained from an iso(thio)cyanate compound and a bifunctional or higher functional active hydrogen compound. Examples of the bifunctional or higher functional active hydrogen compound include a polyol compound and a polythiol compound.

[0034] Examples of the iso(thio)cyanate compound include hexamethylene diisocyanate, pentamethylene diisocyanate, xylylene diisocyanate, isophorone diisocyanate, bis(isocyanatomethyl)cyclohexane, bis(isocyanatocyclohexyl)methane, 2,5-bis(isocyanatomethyl)bicyclo-[2.2.1]-heptane, 2,6-bis(isocyanatomethyl)bicyclo-[2.2.1]-heptane, tolylene diisocyanate, phenylene diisocyanate, and 4,4'-diphenylmethane diisocyanate.

[0035] Examples of polythiol compounds include pentaerythritol tetrakis(2-mercaptoacetate), pentaerythritol tetrakis(3-mercaptopropionate), bis(2-mercaptoethyl) sulfide, 4-mercaptomethyl-1,8-dimercapto-3,6-dithiaoctane, 5,7-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, 4,7-dimercaptomethyl-1,11-dimercapto-3,6, 9-trithiaundecane, 4,8-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, 2,5-dimercaptomethyl-1,4-dithiane, 1,1,3,3-tetrakis(mercaptomethylthio)propane, 4,6-bis(mercaptomethylthio)-1,3-dithiane, 2-(2,2-bis(mercaptomethylthio)ethyl)-1,3-dithietane, ethylene glycol bis(3-mercaptopropionate), and the like.

[0036] Examples of polyol compounds include ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, 1,3-propanediol, 2,2-dimethyl-1,3-propanediol, 2,2-diethyl-1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 3-methyl-1,3-butanediol, 1,2-pentanediol, 1,3-pentanediol, 1,5-pentanediol, 2,4-pentanediol, 2-methyl-2,4-pentanediol, 3-methyl linear or branched aliphatic alcohols such as 1,5-pentanediol, 1,6-hexanediol, 2,5-hexanediol, glycerol, diglycerol, polyglycerol, trimethylolpropane, pentaerythritol, and di(trimethylolpropane); and alicyclic alcohols such as 1,2-cyclopentanediol, 1,3-cyclopentanediol, 3-methyl-1,2-cyclopentanediol, 1,2-cyclohexanediol, 1,3-cyclohexanediol, 1,4-cyclohexanediol, 4,4'-bicyclohexanol, and 1,4-cyclohexanedimethanol.

[0037] The thickness of the (thio)urethane-based optical resin layer is preferably 2.0 mm or less, more preferably 1.5 mm or less, even more preferably 1.0 mm or less, even more preferably 0.8 mm or less, even more preferably 0.6 mm or less, and even more preferably 0.4 mm or less.

[0038] The refractive index of the (thio)urethane-based optical resin layer at a temperature of 25°C and a wavelength of 587.6 nm according to JIS K-0062:1992 is, from the viewpoint of improving the optical properties of the optical laminate, preferably 1.47 or more, more preferably 1.49 or more, even more preferably 1.51 or more, and still more preferably 1.53 or more, and may be, for example, 1.90 or less, 1.80 or less, or 1.70 or less.

[0039] The linear expansion coefficient of the (thio)urethane-based optical resin layer measured under the following <Measurement Conditions> is preferably 100×10 from the viewpoint of further suppressing warping of the optical laminate and suppressing peeling of the optical laminate. －６ / °C or less, more preferably 80 x 10 －６ / °C or less, and from the viewpoint of further suppressing warping of the optical laminate and suppressing peeling of the optical laminate, it is better that the difference in linear expansion coefficient between the optical laminate and the optical substrate is small. Therefore, it is preferably 2 × 10 －６ / °C or more, more preferably 4 x 10 －６ / °C or more, more preferably 6 × 10 －６ / °C or more, more preferably 8 x 10 －６ / °C or more. <Measurement conditions> Measurement mode: TMA compression mode Test load: 50 mN Heating rate: 5°C / min Test temperature range: 23 to 200°C Measurement atmosphere: nitrogen (100 ml / min)

[0040] <Optical Substrate> Hereinafter, the optical substrate of the optical laminate of this embodiment will be described.

[0041] The optical substrate preferably includes one or more types selected from the group consisting of a glass substrate and an optical crystal substrate. Examples of the optical crystal substrate include a SiC substrate, a LiNb ２ O ３ Substrate (LN substrate), Al ２ O ３ Examples of the substrate include a sapphire substrate, a crystal substrate, and a quartz substrate.

[0042] The refractive index of the optical substrate at a temperature of 25°C and a wavelength of 587.6 nm according to JIS K-0062:1992 is, from the viewpoint of improving the optical properties of the optical laminate, preferably 1.47 or more, more preferably 1.49 or more, even more preferably 1.51 or more, and still more preferably 1.53 or more, and may be, for example, 1.90 or less, 1.80 or less, or 1.70 or less.

[0043] The linear expansion coefficient of the optical substrate measured under the following <Measurement Conditions> is preferably 0.1 × 10 because the difference in linear expansion coefficient between the adhesive layer and the (thio)urethane-based optical resin layer is preferably small from the viewpoint of further suppressing warping of the optical laminate and suppressing peeling of the optical laminate. －６ / °C or more, more preferably 0.5 × 10 －６ / °C or more, more preferably 2 × 10 －６ / °C or more, more preferably 4 x 10 －６ / °C or more, and for example, 40 x 10 －６ / °C or less, and －６ / °C or less. <Measurement conditions> Measurement mode: TMA compression mode Test load: 50 mN Heating rate: 5°C / min Test temperature range: 23 to 200°C Measurement atmosphere: nitrogen (100 ml / min)

[0044] <Other Layer Configurations> The optical laminate of this embodiment may include configurations other than the adhesive layer, the (thio)urethane-based optical resin layer, and the optical substrate.

[0045] The optical laminate of this embodiment preferably further includes a transparent inorganic layer between the optical substrate and the adhesive layer in order to prevent peeling of the optical laminate. The means for forming the transparent inorganic layer is not particularly limited, but it can be formed, for example, by sputtering the surface of the optical substrate. Specifically, the optical substrate is first placed in a vacuum chamber, a gas such as argon gas is introduced, and then a negative voltage is applied to the surface of the optical substrate to generate a glow discharge and ionize the gas atoms. This causes the ionized gas atoms to collide with the surface of the optical substrate, ejecting particles (atoms and molecules) from the surface of the optical substrate and adhering and depositing on the surface of the optical substrate, thereby forming a transparent inorganic layer.

[0046] The thickness of the transparent inorganic layer is not particularly limited, but from the viewpoint of further suppressing warping of the optical laminate and suppressing peeling of the optical laminate, it is preferably 5 nm or more, more preferably 10 nm or more, even more preferably 20 nm or more, still more preferably 50 nm or more, and is, for example, 100 nm or less.

[0047] From the viewpoint of suppressing peeling of the optical laminate of this embodiment, the optical laminate of this embodiment preferably further includes a coupling agent layer between the optical substrate and the adhesive layer.

[0048] The coupling agent contained in the coupling agent layer is not particularly limited, and examples thereof include silane coupling agents. Examples of the silane coupling agent include vinyl group-containing silane coupling agents such as vinyltrimethoxysilane and vinyltriethoxysilane, epoxy group-containing silane coupling agents such as 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane and 3-glycidoxypropyltriethoxysilane, and (meth)acrylic group-containing silane coupling agents such as 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropyltriethoxysilane and 3-acryloxypropyltrimethoxysilane.

[0049] The thickness of the coupling agent layer is not particularly limited, but from the viewpoint of further suppressing warping of the optical laminate and suppressing peeling of the optical laminate, it is preferably 1 nm or more, more preferably 2 nm or more, even more preferably 5 nm or more, and even more preferably 10 nm or more, and may be, for example, 50 nm or less.

[0050] In addition to the configuration described above, the optical laminate of this embodiment may include layer configurations such as an antistatic layer that prevents the optical laminate from being charged, a hard coat layer that prevents the optical laminate from being scratched, a moisture-blocking layer that blocks moisture from penetrating into the optical laminate, and an antireflection film that reduces surface reflection of the optical laminate.

[0051] <Physical Properties and Applications of Optical Laminate> Hereinafter, the physical properties and applications of the optical laminate of this embodiment will be described.

[0052] The amount of warpage F of the surface A on the (thio)urethane-based optical resin layer side of the optical laminate of this embodiment Ａis preferably 350 μm or less, more preferably 300 μm or less, even more preferably 250 μm or less, even more preferably 200 μm or less, even more preferably 150 μm or less, even more preferably 100 μm or less, even more preferably 50 μm or less, and may be, for example, 0.01 μm or more.

[0053] Amount of warpage F Ａ can be measured using an ultra-high precision three-dimensional measuring machine. Specifically, the measurement can be performed under the following conditions: Apparatus: UA3P (manufactured by Panasonic Production Engineering Co., Ltd.) Measurement area: a circular area of ​​±30 mm in the X and Y directions from the center of the optical laminate.

[0054] When the optical laminate of this embodiment is left standing for 360 hours in an environment at a temperature of 60° C. and a humidity of 90%, the (thio)urethane-based optical resin layer preferably does not peel off from the optical substrate.

[0055] The refractive index of the optical laminate at a temperature of 25°C and a wavelength of 587.6 nm according to JIS K-0062:1992 is, from the viewpoint of improving the optical properties of the optical laminate, preferably 1.47 or more, more preferably 1.49 or more, even more preferably 1.51 or more, and still more preferably 1.53 or more, and may be, for example, 1.90 or less, 1.80 or less, or 1.70 or less.

[0056] The use of the optical laminate of the present embodiment is not particularly limited, but it can be used in wearable devices, and more specifically, it can be used in wearable displays that display virtual reality (VR), augmented reality (AR), and the like.

[0057] [Method for Producing Optical Laminate] Hereinafter, a method for producing the optical laminate of this embodiment will be described.

[0058] The method for producing an optical laminate of this embodiment includes a step (A) of preparing a laminate including an optical substrate, a (thio)urethane-based optical resin layer on at least one surface of the optical substrate, and an uncured or semi-cured adhesive layer between the optical substrate and the (thio)urethane-based optical resin layer, and a step (B) of curing the uncured or semi-cured adhesive layer to obtain the optical laminate.

[0059] The method for producing an optical laminate of this embodiment may further include a step (C) of placing the laminate in a reduced pressure environment before the step (B). This can prevent misalignment of the components during lamination. This can also prevent air bubbles from forming between the layers.

[0060] The method for producing an optical laminate of this embodiment may further include a step of sputtering the surface of the optical substrate. By sputtering the surface of the optical substrate, a transparent inorganic layer can be formed on the surface of the optical substrate.

[0061] The method for producing an optical laminate of this embodiment may further include a step of performing surface treatment plasma ashing on the surface of the optical substrate. By performing plasma ashing on the surface of the optical substrate, the surface of the optical substrate can be activated.

[0062] The method for producing an optical laminate of this embodiment may further include a step of applying a coupling agent to the surface of the optical substrate. By applying the coupling agent to the surface of the optical substrate, a coupling agent layer can be formed on the surface of the optical substrate.

[0063] In the manufacturing method of the optical laminate of this embodiment, it is preferable to apply a coupling agent to the sputtered surface of the optical substrate from the viewpoint of further suppressing warping of the optical laminate and suppressing peeling of the optical laminate.

[0064] [Optical Information Transmission Device] Hereinafter, an optical information transmission device according to this embodiment will be described.

[0065] The optical information transmission device of this embodiment will be described with reference to Fig. 2. The optical information transmission device 20 of this embodiment includes a light irradiation unit 11 and the optical laminate 10 described above.

[0066] Light 12 emitted from the light emitting unit 11 is reflected by the optical laminate 10, and the reflected light is irradiated onto the user's eye 13. As a result, the light emitted from the light emitting unit 11 is recognized by the user wearing the optical information transmission device 10.

[0067] Although the embodiments of the present invention have been described above, these are merely examples of the present invention, and various other configurations may be adopted. Furthermore, the present invention is not limited to the above-described embodiments, and modifications and improvements within the scope of achieving the object of the present invention are included in the present invention.

[0068] The present invention will be explained in more detail below with reference to examples, but the present invention is not limited to the following examples as long as it does not depart from the gist of the invention.

[0069] <Optical laminate> The following materials were prepared: Glass substrate (1) (manufactured by Corning Incorporated, diameter 80 mm, thickness 0.5 mm, refractive index 1.51, linear expansion coefficient 31.7×10 ―７ / °C) Thiourethane-based optical resin sheet (1) (manufactured by Mitsui Chemicals, Inc., product name SK-600, diameter 78 mm, thickness 0.35 mm, refractive index 1.67, linear expansion coefficient 6.5 × 10 ―５ / °C) Adhesive resin composition (A) (acrylic, ultraviolet curable) Adhesive resin composition (B) (acrylic, ultraviolet curable) Adhesive resin composition (C) (acrylic, ultraviolet curable) Adhesive resin composition (D) (acrylic, ultraviolet curable) Adhesive resin composition (E) (epoxy, thermosetting) Adhesive resin composition (F) (epoxy, thermosetting)

[0070] (Examples 1 to 4) A glass substrate (1) was sputtered to form a transparent inorganic layer on the surface of the glass substrate (1). Metallic Si was used as the sputtering target. Ar and O were used as the carrier gas. ２The sputtering power was 5.5 kW. The method for forming the transparent inorganic layer is not particularly limited, and the layer may be formed by ion-assisted deposition. Next, a silane coupling agent (manufactured by Shin-Etsu Chemical Co., Ltd., product name KBM-5103) was applied to the transparent inorganic layer of the glass substrate (1) to form a silane coupling agent layer with a thickness of 7 nm. Next, the adhesive resin compositions shown in Table 1 were applied to the silane coupling agent layer of the glass substrate (1) so that the thickness after curing would be 50 μm. Next, a thiourethane-based optical resin sheet (1) was laminated on the surface on which the adhesive resin composition was applied, and ultraviolet light with a wavelength of 405 nm was irradiated at an irradiation intensity of 600 mW / cm. ２ The adhesive resin composition was cured by irradiation with light at a rate of 1000 kJ / cm for 50 seconds, and an optical laminate was obtained.

[0071] Example 5 An optical laminate was obtained in the same manner as in Example 1, except that the thickness of the adhesive layer was 20 μm.

[0072] Example 6 An optical laminate was obtained in the same manner as in Example 3, except that the thickness of the adhesive layer was 20 μm.

[0073] (Comparative Examples 1 and 2) A glass substrate (1) was sputtered under the same conditions as when the transparent inorganic substance layer of Example 1 was formed, to form a transparent inorganic substance layer on the surface of the glass substrate (1). Next, a silane coupling agent layer was formed on the transparent inorganic substance layer of the glass substrate (1) under the same conditions as when the silane coupling agent layer of Example 1 was formed. Next, an adhesive resin composition shown in Table 1 was applied to the silane coupling agent layer of the glass substrate (1) so that the thickness after curing would be 50 μm. Next, a thiourethane-based optical resin sheet (1) was laminated on the surface on which the adhesive resin composition was applied, and ultraviolet light having a wavelength of 405 nm was irradiated at an irradiation intensity of 600 mW / cm. ２ The adhesive resin composition was cured by irradiating the adhesive resin composition with light at 80° C. for 50 seconds and then heating at 80° C. for 30 minutes to obtain an optical laminate.

[0074] <Viscosity of adhesive resin composition> Using a cone-plate viscometer (manufactured by Brookfield, model name: DV2T) and further using a CPA-40G cone spindle (angle: 0.8°, radius: 24 mm, sample amount: 0.5 mL, shear rate: 7.5 N / s), the viscosity of the adhesive resin composition was measured at a temperature of 25° C. The results are shown in Table 1.

[0075] <Preparation of Samples for Evaluating Adhesive Layer> (Examples 1 to 6) Each adhesive resin composition shown in Table 1 was applied to a PET sheet so that the thickness after curing would be 0.1 mm. Then, ultraviolet light with a wavelength of 405 nm was irradiated at an intensity of 600 mW / cm. ２ The adhesive resin composition was then irradiated with ultraviolet light at a wavelength of 405 nm for 50 seconds to cure the adhesive resin composition. The cured adhesive resin composition was then peeled off from the PET sheet and cut into a piece 10 mm wide and 20 mm long to obtain a sample for adhesive layer evaluation. (Comparative Examples 1 and 2) Each adhesive resin composition shown in Table 1 was applied to a PET sheet so that the thickness after curing would be 0.1 mm. Next, ultraviolet light with a wavelength of 405 nm was applied at an irradiation intensity of 600 mW / cm. ２ The adhesive resin composition was cured by irradiating the adhesive resin composition with light at 80° C. for 50 seconds and then heating at 80° C. for 30 minutes. The cured adhesive resin composition was then peeled off from the PET sheet and cut into a piece having a width of 10 mm and a length of 20 mm to obtain a sample for evaluating the adhesive layer.

[0076] <Glass Transition Temperature of Adhesive Layer> The glass transition temperature of the adhesive layer evaluation sample obtained by the above method was measured under the following conditions. The results are shown in Table 1. Apparatus: DMA7100 (manufactured by Hitachi High-Tech Science Corporation) Temperature range: 0 to 200°C Heating rate: 5°C / min Measurement interval: 3 seconds Measurement frequency: 1 Hz Measurement mode: Tension

[0077] <Loss modulus of adhesive layer> The loss modulus of the adhesive layer evaluation sample obtained by the above method was measured under the following conditions. The results are shown in Table 1. Apparatus: DMA7100 (manufactured by Hitachi High-Tech Science Corporation) Sample shape: Width 10 mm × Thickness 0.1 mm × Length 20 mm Measurement temperature: 25°C Measurement frequency: 1 Hz Measurement mode: Tension

[0078] <Refractive Index of Adhesive Layer> Using the adhesive layer evaluation sample obtained by the method described above, the refractive index was measured at a temperature of 25°C and a wavelength of 587.6 nm with an Abbe refractometer in accordance with JIS K-0062: 1992. The results are shown in Table 1.

[0079] <Cure shrinkage rate of adhesive layer> The density D of the adhesive layer before curing was measured in accordance with JIS K-5600-2-4:2014 using the adhesive layer evaluation sample obtained by the above method. ０ and density after hardening D １ The cure shrinkage was calculated from the following formula (1). The results are shown in Table 1. Cure shrinkage (%) = (D １ -D ０ ) / D ０ (1)

[0080] <Warpage of Optical Laminate (23°C)> The optical laminate obtained by the above method was allowed to stand at room temperature (23°C) for 1 hour, and then the warpage was measured under the following conditions. Apparatus: UA3P (manufactured by Panasonic Production Engineering Co., Ltd.) Measurement area: Circular area of ​​±30 mm from the center of the optical laminate in the X and Y directions The obtained warpage was evaluated according to the following criteria. The results are shown in Table 1. A: 100 μm or less B: More than 100 μm to 350 μm or less C: More than 350 μm

[0081]

[0082] Warpage was suppressed in the optical laminates of the examples, which shows that warpage can be suppressed in the optical laminate of this embodiment.

[0083] <Warpage of Optical Laminate (50°C)> The optical laminate obtained by the above method was allowed to stand at 50°C for 30 minutes, and then the warpage was measured under the following conditions. The results are shown in Table 2. Apparatus: UA3P (manufactured by Panasonic Production Engineering Co., Ltd.) Measurement area: Circular area of ​​±30 mm from the center of the optical laminate in the X and Y directions.

[0084]

[0085] The amount of warping decreased as the thickness of the adhesive layer increased, which indicates that warping can be further suppressed by increasing the thickness of the adhesive layer.

[0086] This application claims priority based on Japanese Patent Application No. 2023-118126, filed on July 20, 2023, the disclosure of which is incorporated herein by reference in its entirety.

[0087] REFERENCE SIGNS LIST 1 Optical substrate 2 (Thio)urethane-based optical resin layer α 3 (Thio)urethane-based optical resin layer β 10 Optical laminate 11 Light irradiation unit 12 Light 13 Eye 20 Optical information transmission device

Claims

1. an optical substrate; a (thio)urethane-based optical resin layer on at least one surface of the optical substrate; an adhesive layer between the optical substrate and the (thio)urethane-based optical resin layer; Including, An optical laminate, wherein the adhesive layer has a glass transition temperature of 70°C or lower.

2. 2. The optical laminate according to claim 1, wherein the loss modulus of the adhesive layer is 0.001 GPa or more and 1.5 GPa or less, measured in a tensile measurement mode at a temperature of 25°C and a measurement frequency of 1 Hz.

3. The optical laminate according to claim 1 or 2, wherein the adhesive layer has a thickness of 0.5 μm or more and 1000 μm or less.

4. Density D of the adhesive layer before curing measured in accordance with JIS K-5600-2-4:2014 ０ and density after hardening D １ 3. The optical laminate according to claim 1, wherein the cure shrinkage obtained by the following formula (1) is 10% or less: Hardening shrinkage rate (%) = (D １ -D ０ ) / D ０ (1)

5. 3. The optical laminate according to claim 1, wherein the refractive index of the adhesive layer at a temperature of 25° C. and a wavelength of 587.6 nm according to JIS K-0062:1992 is 1.47 or more.

6. The optical laminate according to claim 1 or 2, wherein the adhesive layer comprises one or more resins selected from the group consisting of (meth)acrylic resins and epoxy resins.

7. 3. The optical laminate according to claim 1, wherein the adhesive layer is made of a cured product of an adhesive resin composition, and the adhesive resin composition is a photocurable resin composition or a thermosetting resin composition.

8. 3. The optical laminate according to claim 1, wherein the (thio)urethane-based optical resin layer has a thickness of 2.0 mm or less.

9. 3. The optical laminate according to claim 1, wherein the refractive index of the (thio)urethane-based optical resin layer at a temperature of 25° C. and a wavelength of 587.6 nm according to JIS K-0062:1992 is 1.47 or more.

10. The optical laminate according to claim 1 or 2, wherein the optical substrate comprises one or more substrates selected from the group consisting of glass substrates and optical crystal substrates.

11. 3. The optical laminate according to claim 1, wherein the refractive index of the optical substrate at a temperature of 25° C. and a wavelength of 587.6 nm in accordance with JIS K-0062:1992 is 1.47 or more.

12. The optical laminate according to claim 1 or 2, further comprising a transparent inorganic layer between the optical substrate and the adhesive layer.

13. The optical laminate according to claim 1 or 2, further comprising a coupling agent layer between the optical substrate and the adhesive layer.

14. The amount of warpage F of the surface A on the (thio)urethane-based optical resin layer side of the optical laminate Ａ The optical laminate according to claim 1 or 2, wherein the thickness is 350 μm or less.

15. 3. The optical laminate according to claim 1, wherein the (thio)urethane-based optical resin layer does not peel off from the optical substrate when the optical laminate is left standing for 360 hours in an environment at a temperature of 60°C and a humidity of 90%.

16. 3. The optical laminate according to claim 1, wherein the refractive index of the optical laminate at a temperature of 25° C. and a wavelength of 587.6 nm according to JIS K-0062:1992 is 1.47 or more.

17. The optical laminate according to claim 1 or 2, which can be used in a wearable device.

18. A step (A) of preparing a laminate including an optical substrate, a (thio)urethane-based optical resin layer on at least one surface of the optical substrate, and an uncured or semi-cured adhesive layer between the optical substrate and the (thio)urethane-based optical resin layer; Step (B) of curing the uncured or semi-cured adhesive layer to obtain an optical laminate; A method for producing an optical laminate, comprising:

19. The method for producing an optical laminate according to claim 18 , further comprising, before the step (B), a step (C) of placing the laminate in a reduced pressure environment.

20. A light irradiation unit; The optical laminate according to claim 1 or 2, An optical information transmission device comprising: