Laminate, optical component and optical device

Abstract

To provide a laminate capable of being used as an optical component such as a lens, and having an anti-reflection layer, the laminate having excellent reflow resistance.SOLUTION: A laminate comprises a substrate and an anti-reflection layer covering the surface of the substrate, where the anti-reflection layer has a moth-eye structure, and has a linear expansion coefficient of 2×10-4 / K or less at 230°C to 240°C.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present disclosure relates to a laminate, an optical component constructed from the laminate, and an optical device including the optical component. [Background technology]

[0002] Generally, resin lenses are easier to process and can be made smaller and thinner than glass or glass-resin composite lenses. However, lenses made of thermoplastic resin are vulnerable to heat and can deform or crack when mounted on optical devices using a heating and bonding process known as reflow.

[0003] Patent Document 1 discloses that when forming an anti-reflection film on the surface of a lens array, durability against reflow processing can be improved by maintaining the film formation temperature within a range of -40°C to +40°C relative to the melting temperature of solder, etc.

[0004] Patent Document 2 reports that by forming an anti-reflection structure on the optical function part, i.e., the lens, the difference in linear expansion coefficient between the anti-reflection structure and the optical function part is small, which has the effect of preventing cracks from occurring. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-244583 [Patent Document 2] Japanese Patent Application Laid-Open No. 2012-212019 Summary of the Invention [Problem to be solved by the invention]

[0006] An object of the present disclosure is to provide a laminate that can be used as an optical component such as a lens, has an antireflection layer, and has excellent reflow resistance. [Means for solving the problem]

[0007] As a result of extensive research aimed at solving the above-mentioned problems, the present inventors have found that the above-mentioned problems can be solved by a laminate having a substrate and an antireflection layer, the linear expansion coefficient of which is within a specific range, and the antireflection layer having a moth-eye structure.

[0008] That is, the gist of the present disclosure is as follows. [1] A substrate and an anti-reflection layer covering the surface of the substrate, the antireflection layer has a moth-eye structure, Linear expansion coefficient at 230℃~240℃ is 2×10 -4 / K or less. [2] The laminate according to [1], wherein the moth-eye structure has an average pitch of 10 nm or more and 500 nm or less. [3] The laminate according to [1] or [2], wherein the moth-eye structure has an average height of 10 nm or more and 500 nm or less. [4] The laminate according to any one of [1] to [3], wherein the substrate is a cured product of a curable composition containing an epoxy compound. [5] The laminate according to [4], wherein the epoxy compound is at least one selected from the group consisting of alicyclic epoxy compounds, aromatic epoxy compounds, and aliphatic epoxy compounds. [6] The laminate according to any one of [1] to [5], wherein the antireflection layer is made of an inorganic material. [7] The laminate according to any one of [1] to [6], wherein the antireflection layer contains at least one of SiO2 and Al2O3. [8] The laminate according to any one of [1] to [7], wherein at least a portion of the antireflection layer is covered with a water-repellent film. [9] The laminate according to [8], wherein the water-repellent film contains a fluorine-containing compound.

[10] An optical component comprising the laminate according to any one of [1] to [9].

[11] An optical device comprising the optical component according to

[10] . [Effects of the Invention]

[0009] According to the present disclosure, it is possible to provide a laminate that can be used as an optical component such as a lens, has an antireflection layer, and has excellent reflow resistance. DETAILED DESCRIPTION OF THE INVENTION

[0010] Although the following description is an example of an embodiment of the present disclosure, the present disclosure is not limited to the following description as long as it does not deviate from the gist of the disclosure. Furthermore, in this disclosure, a numerical range expressed using "to" means a range that includes the numerical values ​​before and after "to" as the lower and upper limits, and "A to B" means A or more and B or less.

[0011] One embodiment of the present disclosure includes a substrate and an antireflection layer covering a surface of the substrate, the antireflection layer having a moth-eye structure and a linear expansion coefficient of 2×10 at 230° C. to 240° C. -4 / K or less. The linear expansion coefficient of the laminate according to this embodiment at 230°C to 240°C is 2 × 10 -4 / K or less, 1.8×10 -4 / K or less is more preferable, and 1.5×10 -4 The lower limit of the coefficient of linear expansion at 230°C to 240°C is not particularly limited, and is, for example, 4 × 10 -5 / K or higher, 2×10 -5 / K or higher, 0.6×10 -5 That is, the range of the linear expansion coefficient at 230°C to 240°C may be 0 / K or more, 2 × 10 -4 / K or less, and -5 / K or higher, 1.8×10 -4 / K or less, and -5 / K or higher, 1.8×10 -4 / K or less, and -5 / K or higher, 1.5×10 -4 / K or less, or other combinations of the above upper and lower limits. The linear expansion coefficient at 230°C to 240°C can be determined from the slope of the straight line of the thermal expansion coefficient measured in a nitrogen atmosphere at a heating rate of 20°C / min over the measurement temperature range of 230°C to 240°C using a TMA measuring device (TMA / SS100 manufactured by SII Nanotechnology Inc.) according to a method in accordance with JIS K7197.

[0012] The linear expansion coefficient of the laminate according to this embodiment at 20°C to 30°C is not particularly limited, but is preferably 1.0 × 10 -4 / K or less is preferable, and 0.8×10 -4 / K or less is more preferable, and 0.7×10 -4 The lower limit of the coefficient of linear expansion at 20°C to 30°C is not particularly limited, and is, for example, 4 × 10 -5 / K or higher, 2×10 -5 / K or higher, 0.6×10 -5 That is, the range of the linear expansion coefficient at 20°C to 30°C may be 0 / K or more, 1.0 × 10 -4 / K or less, and -5 / K or higher, 0.8×10 -4 / K or less, and -5 / K or higher, 0.8×10 -4 / K or less, and -5 / K or higher, 0.7×10 -4 / K or less, or other combinations of the above upper and lower limits. The linear expansion coefficient at 20°C to 30°C can be determined from the slope of the straight line of the thermal expansion coefficient measured in a nitrogen atmosphere at a heating rate of 20°C / min over a temperature range of 20°C to 30°C using a TMA measuring device (TMA / SS100 manufactured by SII Nanotechnology Inc.) according to a method in accordance with JIS K7197.

[0013] <Base material> The material constituting the substrate is a laminate with a linear expansion coefficient of 2×10 at 230℃ to 240℃. -4 The material is not particularly limited as long as it has a temperature of 1 / K or less. The smaller the linear expansion coefficient of the base material at 230℃ to 240℃, the less likely deformation or cracks will occur during the reflow process. -4 / K or less is preferable, and 1.8×10 -4 / K or less is more preferable, and 1.5×10 -4 The lower limit of the coefficient of linear expansion at 230°C to 240°C is not particularly limited, and is, for example, 4 × 10 -5 / K or higher, 2×10 -5 / K or higher, 0.6×10 -5 That is, the range of the linear expansion coefficient at 230°C to 240°C may be 0 / K or more, 2 × 10 -4 / K or less, and -5 / K or higher, 1.8×10 -4 / K or less, and -5 / K or higher, 1.8×10 -4 / K or less, and -5 / K or higher, 1.5×10 -4 / K or less, or other combinations of the above upper and lower limits. The linear expansion coefficient of the substrate at 230° C. to 240° C. can be measured in the same manner as for the laminate. The linear expansion coefficient can be set within the above range by selecting an appropriate material.

[0014] (epoxy resin) An example of a material constituting the substrate is a cured product of a curable composition containing an epoxy compound. As the epoxy compound, known compounds having one or more epoxy groups (oxirane rings) in the molecule can be used, such as alicyclic epoxy compounds, aromatic epoxy compounds, and aliphatic epoxy compounds. The number of epoxy groups in the molecule may be one or more, or may be two or more. The upper limit of the number of epoxy groups is not particularly limited, but may be five or less, or may be four or less. In this embodiment, a polyfunctional alicyclic epoxy compound having an alicyclic structure and two or more epoxy groups in one molecule is preferred, as it can form a cured product with excellent heat resistance and transparency.

[0015] Specific examples of the polyfunctional alicyclic epoxy compound include: (1) Compounds having an epoxy group consisting of two adjacent carbon atoms and an oxygen atom that form an alicyclic ring (i.e., an alicyclic epoxy group) (2) Compounds having an epoxy group directly bonded to an alicyclic ring by a single bond (3) Compounds having an alicyclic ring and a glycidyl group etc.

[0016] Examples of the above-mentioned (1) compound having an alicyclic epoxy group include compounds represented by the following formula (i). [ka]

[0017] In the above formula (i), X represents a single bond or a linking group (a divalent group having one or more atoms). Examples of the linking group include a divalent hydrocarbon group, an alkenylene group in which some or all of the carbon-carbon double bonds have been epoxidized, a carbonyl group, an ether bond, an ester bond, a carbonate group, an amide group, or a group in which multiple of these are linked together. The cyclohexene oxide group in formula (i) may have a substituent (e.g., an alkyl group) bonded to it.

[0018] Examples of the divalent hydrocarbon group include a linear or branched alkylene group having 1 to 18 carbon atoms, and a divalent alicyclic hydrocarbon group. Examples of the linear or branched alkylene group having 1 to 18 carbon atoms include a methylene group, a methylmethylene group, a dimethylmethylene group, an ethylene group, a propylene group, and a trimethylene group. Examples of the hydrogen group include cycloalkylene groups (including cycloalkylidene groups) such as a 1,2-cyclopentylene group, a 1,3-cyclopentylene group, a cyclopentylidene group, a 1,2-cyclohexylene group, a 1,3-cyclohexylene group, a 1,4-cyclohexylene group, and a cyclohexylidene group.

[0019] Examples of the alkenylene group in the alkenylene group in which some or all of the carbon-carbon double bonds have been epoxidized (sometimes referred to as an "epoxidized alkenylene group") include linear or branched alkenylene groups having 2 to 8 carbon atoms, such as vinylene, propenylene, 1-butenylene, 2-butenylene, butadienylene, pentenylene, hexenylene, heptenylene, and octenylene. In particular, the epoxidized alkenylene group is preferably an alkenylene group in which all of the carbon-carbon double bonds have been epoxidized, and more preferably an alkenylene group having 2 to 4 carbon atoms in which all of the carbon-carbon double bonds have been epoxidized.

[0020] Representative examples of the compound represented by formula (i) above include (3,4,3',4'-diepoxy)bicyclohexyl, bis(3,4-epoxycyclohexylmethyl)ether, 1,2-epoxy-1,2-bis(3,4-epoxycyclohexyl-1-yl)ethane, 2,2-bis(3,4-epoxycyclohexyl-1-yl)propane, 1,2-bis(3,4-epoxycyclohexyl-1-yl)ethane, and compounds represented by formulas (i-1) to (i-10) below. L in formula (i-5) below is an alkylene group having 1 to 8 carbon atoms, and among these, a linear or branched alkylene group having 1 to 3 carbon atoms, such as a methylene group, an ethylene group, a propylene group, or an isopropylene group, is preferred. n in formulas (i-5), (i-7), (i-9), and (i-10) below 1 ~n 8 each independently represents an integer of 1 to 30. [ka] [ka]

[0021] The above-mentioned (1) compound having an alicyclic epoxy group also includes epoxy-modified siloxanes. Examples of epoxy-modified siloxanes include linear or cyclic polyorganosiloxanes having a structural unit represented by the following formula (i'): [ka]

[0022] In the above formula (i'), R 1 represents a substituent containing an epoxy group represented by the following formula (1a) or (1b), and R 2 represents an alkyl group or an alkoxy group. [ka]

[0023] R in the above formulas (1a) and (1b) 1a , R 1b may be the same or different and represent a straight-chain or branched-chain alkylene group, and examples thereof include straight-chain or branched-chain alkylene groups having 1 to 10 carbon atoms, such as a methylene group, a methylmethylene group, a dimethylmethylene group, an ethylene group, a propylene group, a trimethylene group, a tetramethylene group, a pentamethylene group, a hexamethylene group, and a decamethylene group.

[0024] The epoxy equivalent of the epoxy-modified siloxane (based on JIS K 7236) is, for example, 100 or more and 400 or less, and preferably 150 or more and 300 or less.

[0025] As the epoxy-modified siloxane, for example, a commercially available product such as an epoxy-modified cyclic polyorganosiloxane represented by the following formula (i'-1) (for example, trade name "X-40-2670", manufactured by Shin-Etsu Chemical Co., Ltd.) can be used. [ka]

[0026] Examples of the compound (2) having an epoxy group directly bonded to the alicyclic ring through a single bond include: and compounds represented by the following formula (ii): [ka]

[0027] In formula (ii), R' is a group (p-valent organic group) obtained by removing p hydroxyl groups (-OH) from the structural formula of a p-valent alcohol, and p, n 9 Each represents a natural number. p-valent alcohol [R'-(OH) p Examples of the alkyl group include polyhydric alcohols (alcohols having 1 to 15 carbon atoms) such as 2,2-bis(hydroxymethyl)-1-butanol. p is preferably an integer of 1 to 6, and n is preferably an integer of 1 to 6. 9 is preferably 1 to 30. When p is 2 or more, n in the groups in the respective square brackets (outer brackets) 9 and may be the same or different. Specific examples of the compound represented by the formula (ii) include 1,2-epoxy-4-(2-oxiranyl)cyclohexane adduct of 2,2-bis(hydroxymethyl)-1-butanol (for example, trade name "EHPE3150" (manufactured by Daicel Corporation)).

[0028] Examples of the above-mentioned (3) compound having an alicyclic ring and a glycidyl group include hydrogenated aromatic glycidyl ether epoxy compounds such as hydrogenated bisphenol A epoxy compounds, hydrogenated bisphenol F epoxy compounds, hydrogenated biphenol epoxy compounds, hydrogenated phenol novolac epoxy compounds, hydrogenated cresol novolac epoxy compounds, hydrogenated cresol novolac epoxy compounds of bisphenol A, hydrogenated naphthalene epoxy compounds, and hydrogenated products of trisphenolmethane epoxy compounds.

[0029] As the polyfunctional alicyclic epoxy compound, (1) a compound having an alicyclic epoxy group is preferred in that it can give a cured product having high surface hardness and excellent heat resistance and transparency. The compound represented by the above formula (i) is more preferred in that it has a small linear expansion coefficient and is less likely to cause eccentricity, and (3,4,3',4'-diepoxy)bicyclohexyl is particularly preferred.

[0030] The curable composition contains an epoxy compound as a cationically curable compound, but may also contain other cationically curable compounds in addition to the epoxy compound, such as an oxetane compound, a vinyl ether compound, etc. Furthermore, the curable composition may also contain a radically curable compound in addition to the cationically curable compound.

[0031] The proportion of the epoxy compound in the total amount (100% by weight) of the curable compounds contained in the curable composition is, for example, preferably 50% by weight or more and 100% by weight or less, in order to obtain a cured product with high surface hardness and excellent transparency, more preferably 60% by weight or more and 90% by weight or less, particularly preferably 70% by weight or more and 90% by weight or less, and most preferably 80% by weight or more and 90% by weight or less.

[0032] Furthermore, the proportion of (1) the compound having an alicyclic epoxy group in the total amount (100% by weight) of the curable compounds contained in the curable composition is preferably, for example, 20% by weight or more and 70% by weight or less, from the viewpoint of obtaining a cured product having high surface hardness and excellent transparency, more preferably 30% by weight or more and 70% by weight or less, and particularly preferably 40% by weight or more and 60% by weight or less.

[0033] Furthermore, the ratio of the compound represented by formula (i) to the total amount (100% by weight) of the curable compounds contained in the curable composition is, for example, 10% by weight or more and 50% by weight or less. It is preferable in that a cured product having high surface hardness and excellent transparency can be obtained, and it is more preferable that it is 15% by weight or more and 40% by weight or less, and particularly preferable that it is 20% by weight or more and 40% by weight or less.

[0034] (Polymerization initiator) The curable composition may contain a polymerization initiator. The polymerization initiator includes a photopolymerization initiator and a thermal polymerization initiator. Therefore, when the curable composition contains a cationic curable compound, it is preferable that the polymerization initiator contains a photocationic polymerization initiator or a thermal cationic polymerization initiator.

[0035] The cationic photopolymerization initiator is a compound that generates an acid upon irradiation with light and initiates the curing reaction of a curable compound (particularly a cationic curable compound) such as an epoxy compound contained in the curable composition, and is composed of a cationic moiety that absorbs light and an anionic moiety that serves as the source of acid generation.

[0036] Examples of the photocationic polymerization initiator include diazonium salt compounds, iodonium salt compounds, sulfonium salt compounds, phosphonium salt compounds, selenium salt compounds, oxonium salt compounds, ammonium salt compounds, and bromine salt compounds.

[0037] In this embodiment, sulfonium salt compounds are particularly preferred because they can form cured products with excellent curability. Examples of the cation moiety of the sulfonium salt compound include arylsulfonium ions (particularly triarylsulfonium ions) such as (4-hydroxyphenyl)methylbenzylsulfonium ion, triphenylsulfonium ion, diphenyl[4-(phenylthio)phenyl]sulfonium ion, 4-(4-biphenylylthio)phenyl-4-biphenylylphenylsulfonium ion, and tri-p-tolylsulfonium ion.

[0038] The anion moiety of the photocationic polymerization initiator may be, for example, [(Y) s B(Phf) 4-s ] - (wherein Y represents a phenyl group or a biphenylyl group; Phf represents a phenyl group in which at least one hydrogen atom is substituted with at least one selected from a perfluoroalkyl group, a perfluoroalkoxy group, and a halogen atom; and s represents an integer of 0 to 3), BF4 - , [(Rf) t PF 6-t ] - (wherein Rf represents an alkyl group in which 80% or more of the hydrogen atoms are substituted with fluorine atoms, and t represents an integer of 0 to 5), AsF6 - , SbF6 - , SbF5OH - etc.

[0039] Examples of the photocationic polymerization initiator in this embodiment include (4-hydroxyphenyl)methylbenzylsulfonium tetrakis(pentafluorophenyl)borate, 4-(4-biphenylylthio)phenyl-4-biphenylylphenylsulfonium tetrakis(pentafluorophenyl)borate, 4-(phenylthio)phenyldiphenylsulfonium phenyltris(pentafluorophenyl)borate, [4-(4-biphenylylthio)phenyl]-4-biphenylylphenylsulfonium phenyltris(pentafluorophenyl)borate, diphenyl[4-(phenylthio)phenyl]sulfonium tris(pentafluoroethyl)trifluorophosphate, diphenyl[4-(phenylthio)phenyl]sulfonium tetrakis(pentafluorophenyl)borate, diphenyl[4-(phenylthio)phenyl]sulfonium hexafluorophosphate, and 4-(4-biphenylylthio)phenyl-4-biphenylylphenylsulfonium Tris(pentafluoroethyl)trifluorophosphate, bis[4-(diphenylsulfonio)phenyl]sulfide phenyltris(pentafluorophenyl)borate, [4-(2-thioxanthonylthio)phenyl]phenyl-2-thioxanthonylsulfonium phenyltris(pentafluorophenyl)borate, 4-(phenylthio)phenyldiphenylsulfonium hexafluoroantimonate, trade name "Cyclohexyl Racure UVI-6970, Cyracure UVI-6974, Cyracure UVI-6990, Cyracure UVI-950 (all manufactured by Union Carbide Corporation, USA), Irgacure250, Irgacure261, Irgacure264 (all manufactured by BASF), CG-24-61 (manufactured by Ciba-Geigy), Optomer SP-150, Optomer SP-151, Optomer SP-170, Optomer SP-171 (all manufactured by ADEKA Corporation), DAICAT II" (manufactured by Daicel Corporation), "UVAC1590", "UVAC1591" (both manufactured by Daicel-Cytec Co., Ltd.), "CI-2064", "CI-2639", "CI-2624", "CI-2481", "CI-2734", "CI-2855", "CI-2823", "CI-2758", "CIT-1682" (all manufactured by Nippon Soda Co., Ltd.), "PI-2074" (manufactured by Rhodia, tetrakis(pentafluorophenyl)borate Commercially available products such as "triylcumyl iodonium salt," "FFC509" (manufactured by 3M), "BBI-102," "BBI-101," "BBI-103," "MPI-103," "TPS-103," "MDS-103," "DTS-103," "NAT-103," and "NDS-103" (all manufactured by Midori Chemical Co., Ltd.), "CD-1010," "CD-1011," and "CD-1012" (all manufactured by Sartomer Corporation, USA), "CPI-100P," and "CPI-101A" (all manufactured by San-Apro Co., Ltd.) can be used.

[0040] A thermal cationic polymerization initiator is a compound that generates an acid upon heat treatment and initiates the curing reaction of a cationic curable compound contained in a curable composition, and is composed of a cationic moiety that absorbs heat and an anionic moiety that serves as the source of acid generation. One type of thermal cationic polymerization initiator can be used alone, or two or more types can be used in combination.

[0041] Examples of the thermal cationic polymerization initiator include iodonium salt compounds and sulfonium salt compounds.

[0042] Examples of the cationic moiety of the thermal cationic polymerization initiator include a 4-hydroxyphenyl-methyl-benzylsulfonium ion, a 4-hydroxyphenyl-methyl-(2-methylbenzyl)sulfonium ion, a 4-hydroxyphenyl-methyl-1-naphthylmethylsulfonium ion, and a p-methoxycarbonyloxyphenyl-benzyl-methylsulfonium ion.

[0043] Examples of the anion moiety of the thermal cationic polymerization initiator include the same examples as those of the anion moiety of the photocationic polymerization initiator. Examples of the thermal cationic polymerization initiator include 4-hydroxyphenyl-methyl-benzylsulfonium phenyltris(pentafluorophenyl)borate, 4-hydroxyphenyl-methyl-(2-methylbenzyl)sulfonium phenyltris(pentafluorophenyl)borate, 4-hydroxyphenyl-methyl-1-naphthylmethylsulfonium phenyltris(pentafluorophenyl)borate, and p-methoxycarbonyloxyphenyl-benzyl-methylsulfonium phenyltris(pentafluorophenyl)borate.

[0044] The content of the polymerization initiator is, for example, in the range of 0.1 parts by weight or more and 5.0 parts by weight or less, relative to 100 parts by weight of the curable compound (particularly, the cationic curable compound) contained in the curable composition. When the content of the polymerization initiator is 0.1 parts by weight or more, excellent curability can be exhibited and curing defects can be suppressed. Furthermore, when the content of the polymerization initiator is 5.0 parts by weight or less, coloration of the cured product can be suppressed, and a cured product with excellent transparency can be formed.

[0045] (Other ingredients) The curable composition may contain other components in addition to the epoxy compound and polymerization initiator. Examples of the other components include solvents, antioxidants, surface conditioners, photosensitizers, antifoaming agents, leveling agents, coupling agents, surfactants, flame retardants, UV absorbers, colorants, ion adsorbents, pigments, fluorescent materials, and mold release agents. The content of the other components is, for example, 20% by weight or less, preferably 10% by weight or less, and particularly preferably 5% by weight or less, of the total amount of the curable composition. The lower limit is not particularly limited, and may be 0% by weight or more.

[0046] The shape of the substrate is not particularly limited, and examples thereof include a lens shape, a flat plate shape, a curved surface shape, etc., but a lens shape is preferred. Specific examples thereof include shapes such as a microlens and a Fresnel lens.

[0047] The substrate can be produced by a known method, for example, injection molding, by filling a mold with the curable composition and curing it.

[0048] <Anti-reflection layer> In this embodiment, the antireflection layer covers the surface of the substrate and has a moth-eye structure. When the substrate has a shape having a front surface and a back surface, the antireflection layer only needs to cover at least one surface of the substrate, and may cover both surfaces. For example, when the substrate is a lens, the antireflection layer only needs to cover either the convex surface or the concave surface, and may cover both the convex surface and the concave surface.

[0049] The antireflection layer is subjected to stress due to the difference in linear expansion coefficient between the antireflection layer and the substrate during the reflow process, but the moth-eye structure can mitigate the effect of stress and prevent cracks from occurring. Therefore, there are no particular restrictions on the material that constitutes the antireflection layer.

[0050] The antireflection layer preferably contains an inorganic material, and more preferably is made of an inorganic material. Examples of inorganic materials include metal oxides, specifically SiO2, Al2O3, ZrO2, TiO2, and Ta2O5. Among these, it is preferable that the antireflection layer contains at least one of SiO2 and Al2O3, and more preferably Al2O3. When the antireflection layer contains an inorganic material, preferably when it is made of an inorganic material, it is possible to reduce the negative pressure during molding of the substrate and stabilize the molding process, which is more preferable than forming the antireflection layer directly on a resin.

[0051] The antireflection layer may be a single layer or a multilayer. When the antireflection layer is a multilayer, the materials constituting each layer may be the same or different.

[0052] In this embodiment, the antireflection layer has a moth-eye structure. The moth-eye structure refers to a fine uneven structure having a pitch equal to or less than a specific wavelength. The moth-eye structure of the antireflection layer can prevent reflection of light incident on the laminate and can also improve reflow resistance. Specifically, the moth-eye structure may be exemplified by a concave-convex structure including a large number of fine fluffs, pyramids, cones, needles, and the like.

[0053] The average pitch of the moth-eye structure is not particularly limited, but is preferably 10 nm or more and 500 nm or less, more preferably 20 nm or more and 400 nm or less, and particularly preferably 50 nm or more and 300 nm or less. The average height of the moth-eye structure is not particularly limited, but is preferably 10 nm or more and 500 nm or less, more preferably 20 nm or more and 400 nm or less, and particularly preferably 50 nm or more and 300 nm or less. The average pitch and average height of the moth-eye structure can be measured by SEM observation.

[0054] The thickness of the antireflection layer is preferably 10 nm or more and 500 nm or less, more preferably 20 nm or more and 400 nm or less, and particularly preferably 50 nm or more and 300 nm or less. Here, the thickness of the antireflection layer is the thickness including the moth-eye structure. The thickness of the antireflection layer can be adjusted, for example, by the voltage during film formation by sputtering, the film formation time, etc.

[0055] The anti-reflection layer can be formed by vapor deposition, coating, sputtering, etc. In particular, it can be suitably formed by DC sputtering. As a DC sputtering film-forming apparatus, a drum-type sputtering film-forming apparatus (carousel-type sputtering apparatus) or the like can be used.

[0056] In one example, a drum-type sputtering deposition apparatus includes a vacuum chamber as a deposition chamber and a cylindrical drum arranged in the center of the vacuum chamber so as to be rotatable about its own axis. A substrate as a deposition target is held on the outer cylindrical surface of the drum with the deposition surface facing outward.

[0057] A target, a sputtering cathode to which the target is attached, and a sputtering gas inlet are arranged on one side of the vacuum chamber.

[0058] Furthermore, a radical source is preferably disposed on the other side of the vacuum chamber. The radical source has a radical gas inlet and a gun capable of generating plasma. The discharge from the gun is, for example, a high frequency discharge, preferably an RF (Radio Frequency) discharge. It is electricity.

[0059] During operation, while the drum is rotating, a rare gas (e.g., Ar gas) is introduced through the sputtering gas inlet, and a DC voltage is applied to the sputtering cathode (DC discharge) to form an anti-reflective layer (DC sputtering). Alternatively, while the drum is rotating, a rare gas and nitrogen (N2) gas may be introduced through the sputtering gas inlet, and an AC voltage may be applied to the sputtering cathode to form an anti-reflective layer (reactive sputtering). In this case, a thin film of nitride of the target material is formed as the anti-reflective layer. Alternatively, while the drum is rotating, a rare gas may be introduced through the sputtering gas inlet of the sputtering source, a DC voltage may be applied to the sputtering cathode, and a radical source may be operated in conjunction with the introduction of N2 gas (RAS (Radical Assist Sputtering) method).

[0060] Gas is introduced into the vacuum chamber through a radical gas inlet, and the gas is radicalized by the plasma generated by the gun. As the drum rotates and the substrate on the drum passes through the plasma, at least one of reaction and modification occurs on the film-forming surface. Examples of gases introduced through the radical gas inlet include O2 gas, N2 gas, and rare gases. One type of gas may be introduced, or two or more types may be used.

[0061] Preferably, the substrate is cleaned before forming the anti-reflection layer by sputtering. That is, with O2 gas introduced through the radical gas inlet of the radical source, a high-frequency voltage is applied to the gun to generate radical oxygen, which is then irradiated onto the substrate on the outer circumferential surface of the rotating drum for a predetermined period of time. If organic matter or the like is attached to the substrate surface, the organic matter or the like is decomposed and removed by the radical oxygen and ultraviolet light generated by the plasma, cleaning the substrate's film-forming surface. Such cleaning improves the adhesion of the film to be formed later.

[0062] The moth-eye structure can be formed by wet etching, dry etching, imprinting, etc. Alternatively, if possible, a method of attaching a sheet on which a moth-eye structure is formed using a material with the same refractive index as the substrate may be used. The blocking layer can also be formed by a dipping process in which the blocking layer is dipped in a predetermined solution.

[0063] The solvent of the predetermined solution is, for example, water (H2O). The solution is preferably pure water or an aqueous solution containing a trace amount of silica (SiO2). Note that even highly pure water or pure water with normal purity often contains a trace amount of silica. If the solution contains a trace amount of silica, the moth-eye structure is formed and the silica is simultaneously incorporated into the anti-reflection layer.

[0064] The silica concentration in the solution is preferably 10 mg / L or less, more preferably 2 mg / L or less. Within this range, silica is easily incorporated into the anti-reflection layer. 10 mg / L corresponds to the silica concentration in pure water with normal purity.

[0065] The temperature of the solution is, for example, 80° C. or higher and lower than the boiling temperature (100° C. at 1 atmospheric pressure), or 80° C. or higher and 90° C. or lower. When the solution boils, the solution moves relatively vigorously, making it difficult for the moth-eye structure, which is a fine uneven structure, to grow.

[0066] The immersion time in the solution is, for example, 2 seconds to 20 minutes, 5 seconds to 10 minutes, 15 seconds to 5 minutes, or 1 minute to 3 minutes. If the immersion time is too short, the moth-eye structure will not be sufficiently obtained, whereas if the immersion time is too long, the treatment time will be long and the efficiency will be reduced accordingly.

[0067] The substrate and anti-reflection layer immersed in the immersion step are preferably subsequently subjected to a drying step. Drying is performed by blowing hot air at, for example, 80°C. Blowing hot air dries faster than natural drying. Natural drying may be used when quality is more important than efficiency. The temperature of the hot air may be 60°C or higher and 100°C or lower, or 70°C or higher and 90°C or lower.

[0068] The immersion step may be performed multiple times. That is, the substrate and antireflection layer may be immersed in a predetermined solution and then in another solution. The solutions used in each immersion step may be the same or different. In a preferred embodiment, the method includes a low-temperature immersion step in which the substrate is immersed in a solution below 80°C and a high-temperature immersion step in which the substrate is immersed in a solution at 80°C or higher, and the high-temperature immersion step is performed after the low-temperature immersion step. Alternatively, a further low-temperature immersion step may be performed after the high-temperature immersion step. The temperature of the solution in the low-temperature immersion step is preferably 60°C or higher. For example, a first tank, a second tank, and a third tank may be provided, each having a solution temperature of 60, 80, and 90°C, respectively, and the substrate and the anti-reflective layer may be immersed in the first tank, the second tank, the third tank, the second tank, and the first tank, respectively, for a predetermined time, and then dried after five immersions. Multiple tanks having the same solution temperature may be provided. By immersing in a tank having a solution temperature from low to high, thermal shock can be alleviated and the quality of the anti-reflective layer can be improved. Similarly, by immersing in a tank having a solution temperature from high to low, thermal shock can be alleviated and the quality of the anti-reflective layer can be improved.

[0069] By the above-mentioned method, the moth-eye structure can be formed after forming the antireflection layer on the substrate. Alternatively, the antireflection layer with the moth-eye structure formed thereon may be attached to the substrate, but it is preferable to form the moth-eye structure after forming the antireflection layer on the substrate. Wet etching, dry etching, and imprinting can be performed by known methods. For example, a moth-eye structure can be formed by applying a photoresist to a substrate using photolithography, drying the photoresist, forming an etching pattern, and then performing dry etching. By adjusting conditions such as the etching pattern and processing time, a moth-eye structure with a desired average pitch and average height can be formed.

[0070] <Water-repellent film> The antireflection layer of this embodiment may be at least partially coated with a water-repellent film, or the entire antireflection layer may be coated with a water-repellent film. The inventors have found that when the antireflection layer has a moth-eye structure, the minute irregularities may bite into a dicing tape or the like, and adhesive may remain after the tape or the like is peeled off. If the adhesive remains, the desired optical properties may not be obtained. By covering the antireflection layer with a water-repellent film, it is possible to prevent adhesive from remaining in the covered area.

[0071] The thickness of the water-repellent film is not particularly limited, but is preferably 5 nm or more and 50 nm or less, more preferably 5 nm or more and 30 nm or less, and particularly preferably 10 nm or more and 20 nm or less.

[0072] The water-repellent film can be made of known materials, such as a fluorine-containing compound, wax, or silicone. Among these, it is preferable for the water-repellent film to contain a fluorine-containing compound, and it is more preferable for the water-repellent film to contain a carbon compound containing a fluoromethyl group or a silicon compound containing a fluoromethyl group. A water-repellent film containing a carbon compound containing a fluoromethyl group or a silicon compound containing a fluoromethyl group can be formed by the same vapor deposition method, coating method, sputtering method, or the like as the antireflection layer, and is therefore suitable for this embodiment.

[0073] When the water-repellent film contains a fluorine-containing compound, the proportion of the fluorine-containing compound relative to the total amount of the water-repellent film is, for example, preferably 30% by weight or more and 80% by weight or less in order to prevent tape adhesive from remaining, more preferably 30% by weight or more and 65% by weight or less, and particularly preferably 35% by weight or more and 55% by weight or less. When the water-repellent film contains a carbon compound containing a fluoromethyl group or a silicon compound containing a fluoromethyl group, the above proportions can be applied as the proportion of the carbon compound containing a fluoromethyl group or the silicon compound containing a fluoromethyl group relative to the total amount of the water-repellent film.

[0074] The water-repellent film can be formed by a known method such as a vapor deposition method, a coating method, a sputtering method, or a dipping method.

[0075] <Applications of laminates> The laminate of this embodiment can be used as an optical component such as a lens. It can also be used as an optical component array having two or more optical components arranged two-dimensionally. The optical component array can be divided into individual components by a method such as dicing, as needed, to obtain single optical components.

[0076] The laminate of this embodiment has high optical transparency and reflow resistance, and therefore can be suitably used as diffusion optical elements such as imaging lenses and collimator lenses for compact camera modules and microlens arrays for optical sensors installed in various devices. The shape, size, and optical properties of these optical components are not particularly limited and can be designed appropriately by those skilled in the art. Furthermore, by combining lenses with each other, or with diffractive optical elements (HOE, DOE), laser elements, light-reflecting members, light-receiving elements, etc., they can also be provided as optical devices that can utilize light with high efficiency. [Example]

[0077] The present disclosure will be specifically described below with reference to examples, but the present disclosure is not limited to the aspects of the following examples.

[0078] (Influence of the moth-eye structure on the anti-reflection layer on reflow resistance) Example 1 <Preparation of substrate> A mold was used in which perfectly circular lens cavities were arranged two-dimensionally. A curable composition, CELVENUS OTM107 (hereinafter sometimes referred to as OTM107; containing (3,4,3',4'-diepoxy)bicyclohexyl and a thermal polymerization initiator; manufactured by Daicel Corporation), was applied to the substrate using a volumetric dispenser. The applied curable composition was then pressed against the mold (maximum pressing pressure 300 N), and the mold was heated in this state (heated from 80°C at a rate of 15°C / min, and then heated to 170°C for 2 minutes), after which the mold was released at 120°C. This resulted in a 100 mm diameter circular wafer lens array, which had a substrate with multiple lens portions arranged two-dimensionally and connected to each other via joints.

[0079] <Formation of anti-reflection layer> An anti-reflection layer was formed on the wafer lens array obtained above by sputtering Al2O3. The array was then immersed in pure water containing silica at a temperature above 80°C but below the boiling point to form a moth-eye structure. The wafer lens array was then dried in a high-temperature furnace at approximately 80°C.

[0080] <Dicing> The obtained wafer lens array was attached to a dicing tape, and a high-speed rotating blade was used to make lattice-shaped cuts to separate it into individual pieces.The dicing tape was then removed to obtain the laminate of Example 1.

[0081] Example 2 A laminate according to Example 2 was produced in the same manner as in Example 1, except that the diameter of the wafer lens was set to 40 mm.

[0082] Example 3 A laminate according to Example 3 was produced in the same manner as in Example 1, except that a curable composition X (hereinafter, sometimes referred to as composition X, containing an alicyclic epoxy resin and a thermal polymerization initiator) was used as the curable composition.

[0083] Example 4 A laminate according to Example 4 was produced in the same manner as in Example 1, except that the diameter of the wafer lens was set to 40 mm and composition X was used as the curable composition.

[0084] Example 5 A laminate according to Example 5 was prepared in the same manner as in Example 1, except that a UV-curable composition (product name "CELVENUS OUH106"; containing a cationic curable compound and a photocationic polymerization initiator, with 80% by weight of the total cationic curable compound being an epoxy resin (including a polyfunctional alicyclic epoxy compound); viscosity at 25°C and a shear rate of 20 (1 / s): 0.2 Pa·s; breaking strain of the cured product (measured using a 5B-type test piece in accordance with JIS-K7162:1994): 0.8%; light transmittance (450 nm): 90% or more; Tg of the cured product: 100°C or more; manufactured by Daicel Corporation) was used as the curable composition, and UV irradiation (30 mW x 30 seconds) was performed instead of heat treatment.

[0085] Comparative Example 1 A laminate according to Comparative Example 1 was produced in the same manner as in Example 1, except that the antireflection layer was made of two layers, TiO2 and SiO2, and the moth-eye structure was not provided.

[0086] Comparative Example 2 A substrate was prepared in the same manner as in Example 1. TiO2 and SiO2 were sequentially deposited on the substrate by vacuum deposition to form a two-layer antireflection layer. The obtained wafer was divided into individual pieces in the same manner as in Example 1 to prepare a laminate according to Comparative Example 2.

[0087] <Evaluation of reflow resistance> The produced laminate was attached to a substrate by reflow. The laminate was observed under a microscope (100x magnification) to check for the presence or absence of cracks. The results are shown in Table 1.

[0088] [Table 1]

[0089] <Measurement of linear expansion coefficient> The thermal expansion coefficient of the laminate prepared in the same manner as in Example 1 was measured using a TMA measuring device ("TMA / SS100" manufactured by SII NanoTechnology Inc.) in a nitrogen atmosphere at a temperature rise rate of 20°C / min over the measurement temperature range of 20°C to 30°C and 230°C to 240°C according to a method in accordance with JIS K7197. The linear expansion coefficient was calculated from the slope of the straight line of the thermal expansion coefficient. Three samples were used, and the average and maximum values ​​are shown in Table 2.

[0090] [Table 2]

[0091] Each laminate was produced in the same manner as in Examples 2 to 5, and the linear expansion coefficient of the laminate was evaluated in the same manner as in the evaluation method for the linear expansion coefficient described above. As a result, the linear expansion coefficient at 230°C to 240°C was 2 × 10 -4 It was found to be below / K.

[0092] (Improved dicing suitability by providing a water-repellent film) In Examples 1 to 4, it was found that adhesive may remain when the dicing tape is peeled off after dicing. If adhesive remains, there is a risk that the desired optical properties may not be obtained, so a method for preventing adhesive residue was investigated.

[0093] Example 6 <Formation of water-repellent film> A wafer lens array was fabricated in the same manner as in Example 1, an antireflection layer was formed, and a moth-eye structure was formed on the antireflection layer. A water-repellent film was formed on the surface on which the moth-eye structure was formed by vacuum-depositing a fluorine-containing compound. Thereafter, dicing was performed in the same manner as in Example 1 to fabricate a laminate according to Example 6.

[0094] Example 7 A wafer lens array was fabricated, an antireflection layer was formed, and a moth-eye structure was formed on the antireflection layer in the same manner as in Example 2. A water-repellent film was formed on the surface on which the moth-eye structure was formed in the same manner as in Example 6. Thereafter, dicing was performed in the same manner as in Example 1 to fabricate a laminate according to Example 7.

[0095] Example 8 A wafer lens array was fabricated, an antireflection layer was formed, and a moth-eye structure was formed on the antireflection layer in the same manner as in Example 3. A water-repellent film was formed on the surface on which the moth-eye structure was formed in the same manner as in Example 6. Thereafter, dicing was performed in the same manner as in Example 1 to fabricate a laminate according to Example 8.

[0096] Example 9 A wafer lens array was fabricated, an antireflection layer was formed, and a moth-eye structure was formed on the antireflection layer in the same manner as in Example 4. A water-repellent film was formed on the surface on which the moth-eye structure was formed in the same manner as in Example 6. Thereafter, dicing was performed in the same manner as in Example 1 to fabricate a laminate according to Example 9.

[0097] <Dicing evaluation> The ease of peeling from the tape using tweezers and whether or not there was any laminate with residual dicing tape adhesive were evaluated for Examples 1 to 4, 6 to 9 and Comparative Examples 1 and 2. The results are shown in Table 3.

[0098] [Table 3]

Claims

1. A substrate and an anti-reflection layer covering the surface of the substrate, the antireflection layer has a moth-eye structure, Linear expansion coefficient at 230°C to 240°C is 2 x 10 －４ / K or less.

2. The laminate according to claim 1 , wherein the moth-eye structure has an average pitch of 10 nm or more and 500 nm or less.

3. The laminate according to claim 1 , wherein the moth-eye structure has an average height of 10 nm or more and 500 nm or less.

4. The laminate according to claim 1 , wherein the substrate is a cured product of a curable composition containing an epoxy compound.

5. The laminate according to claim 4, wherein the epoxy compound is at least one selected from the group consisting of an alicyclic epoxy compound, an aromatic epoxy compound, and an aliphatic epoxy compound.

6. The laminate of claim 1 , wherein the anti-reflection layer is made of an inorganic material.

7. The anti-reflection layer is made of SiO ２ and Al ２ O ３ The laminate according to claim 1 , comprising at least one of:

8. The laminate according to claim 1 , wherein the antireflection layer is at least partially covered with a water-repellent film.

9. The laminate according to claim 8 , wherein the water-repellent film contains a fluorine-containing compound.

10. An optical component comprising the laminate according to any one of claims 1 to 9.

11. An optical instrument comprising the optical component according to claim 10.

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