Resin composition for lenses, cured product for lenses, and lenses

Abstract

Provided is a resin composition for a lens, the resin composition containing: a cationic photopolymerization initiator (X), which contains a salt formed from an anion represented by general formula (1) and a cation; and an epoxy compound (Y), which contains two or more epoxy groups per molecule. (In general formula (1), R1 through R4 each independently represent a C1-18 alkyl group or a C6-14 aryl group.)

Description

[Technical Field]

[0001] The present invention relates to a resin composition for a lens, a cured product for a lens, and a lens. [Background technology]

[0002] Currently, many electronic devices such as smartphones, tablet computers, and laptop computers are equipped with cameras. As these devices become smaller and more powerful, there is a strong demand for smaller and more powerful camera lenses.

[0003] It is known that silicone resin or acrylic resin is used as a material for the lenses of the cameras mounted on these electronic devices (Patent Documents 1 and 2). It is also known that epoxy resin is used as a material (Patent Document 3). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Special Publication No. 2008-545553 [Patent Document 2] Japanese Patent Application Laid-Open No. 2003-131004 [Patent Document 3] Japanese Patent Application Publication No. 2019-189874 Summary of the Invention [Problem to be solved by the invention]

[0005] Conventional lens materials have room for improvement in terms of achieving the various properties required of lenses, such as optical properties and heat resistance.

[0006] An object of the present invention is to provide a resin composition for lenses that can form a cured product for lenses that has low cure shrinkage, a high refractive index, high light transmittance, and high heat resistance. Another object of the present invention is to provide a lens cured product and a lens that combine low cure shrinkage, a high refractive index, high light transmittance, and high heat resistance. [Means for solving the problem]

[0007] The present inventors have conducted extensive research to solve the above-mentioned problems, and as a result have found that the above-mentioned problems can be solved by using a specific cationic photopolymerization initiator in combination with an epoxy compound, thereby completing the present invention.

[0008] That is, according to the present invention, there are provided a resin composition for a lens, a cured product for a lens, and a lens as shown below.

[0009] [1] a cationic photopolymerization initiator (X) containing a salt formed from an anion represented by general formula (1) and a cation; an epoxy compound (Y) containing two or more epoxy groups in the molecule; A resin composition for a lens comprising: [ka] (In general formula (1), R 1 ~R 4 each independently represents an alkyl group having 1 to 18 carbon atoms or an aryl group having 6 to 14 carbon atoms. [2] The resin composition for lenses according to the above [1], The resin composition for lenses, wherein the epoxy compound (Y) is represented by general formula (2): [ka] (In the general formula (2), R 5 , R 6 , R 8 and R 9 each independently represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or a trifluoromethyl group, R 7 represents a hydrogen atom or a glycidyl group, n is the average number of repetitions and represents a real number in the range of 0 to 30.) [3] The resin composition for a lens according to the above [1] or [2], The resin composition for lenses has an epoxy equivalent of the epoxy compound (Y) of 100 g / eq or more and 200 g / eq or less. [4] The resin composition for a lens according to any one of [1] to [3] above, A resin composition for a lens, wherein the content of the epoxy compound (Y) is 40% by mass or more of the non-volatile components of the resin composition for a lens. [5] The resin composition for a lens according to any one of [1] to [4] above, The resin composition for lenses, wherein the cationic photopolymerization initiator (X) contains an anion represented by either formula (3) or (4). [ka] [ka] [6] The resin composition for a lens according to any one of [1] to [5] above, A resin composition for lenses, wherein the cationic photopolymerization initiator (X) contains a sulfonium ion as a cation. [7] The resin composition for a lens according to any one of [1] to [6] above, A resin composition for a lens, further comprising a monofunctional epoxy compound (Z) represented by general formula (5). [ka] (In the general formula (5), A is selected from a single bond, an oxygen atom, and a sulfur atom; R 10 is alkylene having 1 to 8 carbon atoms, and any methylene group may be substituted with an oxygen atom. [8] The resin composition for lenses according to the above [7], The resin composition for a lens, wherein the monofunctional epoxy compound (Z) is o-phenylphenol glycidyl ether. [9] The resin composition for a lens according to any one of [1] to [8] above, A resin composition for a lens, further comprising an oxetane compound (W).

[10] The resin composition for a lens according to any one of [1] to [9] above, The resin composition for a lens, wherein the oxetane compound (W) is a biphenyl-type oxetane compound.

[11] The resin composition for a lens according to any one of [1] to

[10] above, The resin composition for a lens has a viscosity of 100 mPa·s or more and 5000 mPa·s or less when measured using an E-type viscometer at a temperature of 25°C and a rotation speed of 2.5 rpm.

[12] The resin composition for a lens according to any one of [1] to

[11] above, The lens resin composition was applied to a glass plate to a thickness of 250 μm, and the wavelength was 365 nm, the irradiation intensity was 150 mW / cm, and the cumulative irradiation amount was 3000 mJ / cm. 2 and then heated in a nitrogen atmosphere at 120°C for 30 minutes, the cured product of which satisfies the following requirements (A) to (D): (A) The cure shrinkage of the cured product is 1.0% or more and 5.0% or less. (B) The refractive index of the cured product is 1.57 or more. (C) The cured product has a light transmittance in the thickness direction of 80% or more. (D) The change in light transmittance in the thickness direction of the cured product after heating (125°C for 168 hours) is 10% or less.

[13] The resin composition for a lens according to any one of [1] to

[12] above, A resin composition for lenses used in wafer-level lenses.

[14] A cured product for a lens obtained by curing the resin composition for a lens according to any one of the above [1] to

[13] .

[15] A lens comprising the lens cured product according to

[14] above. [Effects of the Invention]

[0010] The resin composition for lenses of the present invention, having the above-mentioned constitution, can form a cured product having low cure shrinkage, high refractive index, high light transmittance and high heat resistance. Furthermore, since the cured product for a lens of the present invention is obtained by curing the above-mentioned resin composition for a lens, it has a low cure shrinkage rate, a high refractive index, a high light transmittance, and high heat resistance. Furthermore, since the lens of the present invention has a structure in which the above-mentioned lens cured material is laminated, it has a low cure shrinkage rate, a high refractive index, a high light transmittance, and high heat resistance. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a plan view showing an example of the configuration of a wafer-level lens array having a plurality of wafer-level lenses. DETAILED DESCRIPTION OF THE INVENTION

[0012] The present invention will be described below based on embodiments. In this embodiment, "A to B" indicating a numerical range means A or more and B or less unless otherwise specified. In this embodiment, unless otherwise specified, when a group such as an alkyl group "has a substituent," it means that a hydrogen atom present in the structure is substituted with a substituent. The position of the substituent and the number of substituents are not particularly limited. Note that when the substituent has a carbon atom, the number of carbon atoms in the substituted group does not include the number of carbon atoms of the substituent. For example, an ethyl group having a phenyl group as a substituent is considered to be an alkyl group having two carbon atoms. In this embodiment, the non-volatile components refer to the components of the resin composition for a lens excluding volatile components such as solvents.

[0013] [Lens resin composition]

[0014] The lens resin composition according to this embodiment contains a cationic photopolymerization initiator (X) containing a salt formed from an anion represented by general formula (1) and a cation, and an epoxy compound (Y) containing two or more epoxy groups in the molecule.

[0015] [ka]

[0016] In general formula (1), R 1 ~R 4 each independently represents an alkyl group having 1 to 18 carbon atoms or an aryl group having 6 to 14 carbon atoms.

[0017] The lens resin composition according to this embodiment can form a cured product that combines low cure shrinkage, a high refractive index, high light transmittance, and high heat resistance. Although the detailed mechanism is unclear, it is presumed that photocationic polymerization initiators containing anionic gallium hardly generate strong acid components even when heated, thereby suppressing heat-induced deterioration such as coloration. Furthermore, photocationic polymerization initiators containing anionic gallium can suppress adverse effects on various properties such as cure shrinkage, refractive index, and light transmittance while exhibiting polymerization performance at the level of the prior art.

[0018] Hereinafter, each component contained in the resin composition for a lens according to this embodiment will be described in detail.

[0019] <Cationic Photopolymerization Initiator (X)>

[0020] The lens resin composition according to this embodiment contains a cationic photopolymerization initiator (X) containing a salt formed from an anion represented by general formula (1) and a cation.

[0021] [ka]

[0022] In general formula (1), R 1 ~R 4 each independently represents an alkyl group having 1 to 18 carbon atoms or an aryl group having 6 to 14 carbon atoms.

[0023] R in general formula (1) 1 ~R 4 The alkyl group having 1 to 18 carbon atoms represented by is not limited to any of straight-chain, branched-chain, and cyclic. Specific examples thereof include alkyl groups such as a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, a t-butyl group, a hexyl group, an octyl group, a 2-ethylhexyl group, and a decyl group; and cycloalkyl groups such as a cyclopentyl group, a cyclohexyl group, a cyclooctyl group, a norbornyl group, a bicyclononyl group, and a tricyclodecane group.

[0024] R in general formula (1) 1 ~R 4 Specific examples of the aryl group having 6 to 14 carbon atoms represented by include a phenyl group, a tolyl group, a naphthyl group, a biphenyl group, a terphenyl group, a phenanthryl group, and an anthracenyl group.

[0025] R in general formula (1) 1 ~R 4 The alkyl group having 1 to 18 carbon atoms or the aryl group having 6 to 14 carbon atoms represented by may have a substituent.

[0026] R in general formula (1) 1 ~R 4 The substituent that the alkyl group having 1 to 18 carbon atoms or the aryl group having 6 to 14 carbon atoms represented by the formula (I) may have is not particularly limited. Examples of the substituent include a halogen atom, a hydrocarbon group, a halogen-containing group, an oxygen-containing group, a sulfur-containing group, and a nitrogen-containing group.

[0027] Examples of the halogen atom include a fluorine atom, a chlorine atom, and a bromine atom.

[0028] Examples of hydrocarbon groups include alkyl groups such as methyl, ethyl, propyl, isopropyl, n-butyl, t-butyl, hexyl, octyl, 2-ethylhexyl, and decyl; cycloalkyl groups such as cyclopentyl, cyclohexyl, cyclooctyl, norbornyl, bicyclononyl, and tricyclodecane; aryl groups such as phenyl, tolyl, naphthyl, biphenyl, terphenyl, phenanthryl, and anthracenyl; aralkyl groups such as benzyl and phenylethyl; and divalent diene derivative groups such as 1,3-butadienyl, isoprenyl(2-methyl-1,3-butadienyl), piperylenyl(1,3-pentadienyl), 2,4-hexadienyl, 1,4-diphenyl-1,3-pentadienyl, and cyclopentadienyl.

[0029] R 1 ~R 4 Examples of the halogen-containing group that may be possessed by the alkyl group having 1 to 18 carbon atoms represented by the formula (I) include halogen-containing hydrocarbon groups such as trifluoromethyl, pentafluoroethyl, 1,1,1,3,3,3-hexafluoro-2-propyl, and nonafluoro-t-butyl; halogen-containing aryl groups such as pentafluorophenyl and pentachlorophenyl; and the like.

[0030] Examples of oxygen-containing groups include alkoxy groups such as a methoxy group, an ethoxy group, an n-propoxy group, an isopropoxy group, an n-butoxy group, an isobutoxy group, or a t-butoxy group; aryloxy groups such as a phenoxy group, a 2,6-dimethylphenoxy group, or a 2,4,6-trimethylphenoxy group; ester groups such as an acetyloxy group, a benzoyloxy group, a methoxycarbonyl group, a phenoxycarbonyl group, or a p-chlorophenoxycarbonyl group; an ether group; acyl groups such as a formyl group, an acetyl group, a benzoyl group, a p-chlorobenzoyl group, or a p-methoxybenzoyl group; a carboxyl group; a carbonate group; a hydroxy group; a peroxy group; a carboxylic anhydride group; a furyl group; and the like.

[0031] Examples of sulfur-containing groups include mercapto groups; thioester groups such as an acetylthio group, a benzoylthio group, a methylthiocarbonyl group, or a phenylthiocarbonyl group; dithioester groups; alkylthio groups such as a methylthio group or an ethylthio group; arylthio groups such as a phenylthio group, a methylphenylthio group, or a naphthylthio group; thioacyl groups; thioether groups; thiocyanate ester groups; isothiocyanate ester groups; sulfonate ester groups such as a methyl sulfonate group, an ethyl sulfonate group, or a phenyl sulfonate group; sulfonamide groups such as a phenylsulfonamide group, an N-methylsulfonamide group, or an N-methyl-p-toluenesulfonamide group; thiocarboxyl groups; dithiocarboxyl groups; sulfo groups; sulfonyl groups; sulfinyl groups; sulfenyl groups; and the like.

[0032] Examples of nitrogen-containing groups include an amino group; alkylamino groups such as a dimethylamino group or an ethylmethylamino group; arylamino groups such as a diphenylamino group; imino group; alkylimino groups such as a methylimino group, an ethylimino group, a propylimino group, or a butylimino group; arylimino groups such as a phenylimino group; an amido group; alkylamido groups such as an acetamido group or an N-methylacetamido group; arylamido groups such as an N-methylbenzamido group; an imido group; alkylimido groups such as an acetimido group; arylimido groups such as a benzimido group; a pyrrolidino group; a hydrazino group; a hydrazono group; a nitro group; a nitroso group; a cyano group; an isocyano group; a cyanate ester group; an amidino group; a diazo group; an amino group; and the like.

[0033] R 1 ~R 4 Preferably, three or more of R are aryl groups having 6 to 14 carbon atoms. 1 ~R 4 It is more preferable that all of the groups are aryl groups having 6 to 14 carbon atoms.

[0034] R 1 ~R 4Preferably, the photocationic polymerization initiator (X) has a halogen atom as a substituent, and more preferably a fluorine atom as a substituent. Specifically, it is particularly preferable that the photocationic polymerization initiator (X) contains an anion represented by either formula (3) or (4) as an anion. This can further improve the heat resistance of a cured lens body formed from the lens resin composition.

[0035] [ka]

[0036] [ka]

[0037] The cationic photopolymerization initiator (X) contains a cation that forms a salt with the anion represented by general formula (1).

[0038] The cation that forms a salt with the anion represented by general formula (1) is not particularly limited as long as it is a monovalent cation, and examples thereof include an oxonium ion, an ammonium ion, a phosphonium ion, a sulfonium ion, and an iodonium ion.

[0039] Examples of oxonium ions include oxonium ions such as trimethyloxonium, diethylmethyloxonium, triethyloxonium, and tetramethylenemethyloxonium; pyrilinium ions such as 4-methylpyrilinium, 2,4,6-trimethylpyrilinium, 2,6-di-tert-butylpyrilinium, and 2,6-diphenylpyrilinium; chromenium ions such as 2,4-dimethylchromenium and 1,3-dimethylisochromenium; isochromenium ions; Examples include:

[0040] Examples of ammonium ions include pyrrolidinium ions such as N,N-dimethylpyrrolidinium, N-ethyl-N-methylpyrrolidinium, and N,N-diethylpyrrolidinium; imidazolinium ions such as N,N'-dimethylimidazolinium, N,N'-diethylimidazolinium, N-ethyl-N'-methylimidazolinium, 1,3,4-trimethylimidazolinium, and 1,2,3,4-tetramethylimidazolinium; tetrahydropyrimidinium ions such as N,N'-dimethyltetrahydropyrimidinium; and morpholinium ions such as N,N'-dimethylmorpholinium. pyridiniums such as N-methylpyridinium, N-benzylpyridinium, and N-phenacylpyridinium; imidazoliums such as N,N'-dimethylimidazolium; quinoliums such as N-methylquinolium, N-benzylquinolium, and N-phenacylquinolium; isoquinoliums such as N-methylisoquinolium; thiazoniums such as benzylbenzothiazonium and phenacylbenzothiazonium; and acridiums such as benzylacridium and phenacylacridium.

[0041] Examples of phosphonium ions include tetraarylphosphonium ions such as tetraphenylphosphonium, tetra-p-tolylphosphonium, tetrakis(2-methoxyphenyl)phosphonium, tetrakis(3-methoxyphenyl)phosphonium, and tetrakis(4-methoxyphenyl)phosphonium; triarylphosphonium ions such as triphenylbenzylphosphonium, triphenylphenacylphosphonium, triphenylmethylphosphonium, and triphenylbutylphosphonium; and tetraalkylphosphonium ions such as triethylbenzylphosphonium, tributylbenzylphosphonium, tetraethylphosphonium, tetrabutylphosphonium, tetrahexylphosphonium, triethylphenacylphosphonium, and tributylphenacylphosphonium; and the like.

[0042] Sulfonium ions include triphenylsulfonium, tri-p-tolylsulfonium, tri-o-tolylsulfonium, tris(4-methoxyphenyl)sulfonium, 1-naphthyldiphenylsulfonium, 2-naphthyldiphenylsulfonium, tris(4-fluorophenyl)sulfonium, tri-1-naphthylsulfonium, tri-2-naphthylsulfonium, tris(4-hydroxyphenyl)sulfonium, 4-(phenylthio)phenyldiphenylsulfonium, 4-(p-tolylthio)phenyldi-p-tolylsulfonium, 4-(4-methoxyphenylthio)phenylbis(4-methoxyphenyl)sulfonium, 4-(phenylthio)phenylbis(4-fluorophenyl)sulfonium, 4-(phenylthio)phenylbis(4-methoxyphenyl)sulfonium, 4-(phenylthio)phenyldi-p-tolylsulfonium, [4-(4-biphenylylthio)phenyl]-4-biphenylylphenylsulfonium, [4-(2-thioxanthonylthio)phenyl )phenyl]diphenylsulfonium, bis[4-(diphenylsulfonio)phenyl]sulfide, bis[4-{bis[4-(2-hydroxyethoxy)phenyl]sulfonio}phenyl]sulfide, bis{4-[bis(4-fluorophenyl)sulfonio]phenyl}sulfide, bis{4-[bis(4-methylphenyl)sulfonio]phenyl}sulfide, bis{4-[bis(4-methoxyphenyl)sulfonio]phenyl}sulfide, 4-(4-benzoyl-2-chlorophenyl) 4-(4-benzoyl-2-chlorophenylthio)phenyldiphenylsulfonium, 4-(4-benzoylphenylthio)phenylbis(4-fluorophenyl)sulfonium, 4-(4-benzoylphenylthio)phenyldiphenylsulfonium, 4-(4-benzoylphenylthio)phenyldiphenylsulfonium, 7-isopropyl-9-oxo-10-thia-9,10-dihydroanthracen-2-yldi-p-tolylsulfonium, 7-isopropyl-9-oxo-10-thia-9,10-dihydroanthracen-2-yldi-p-tolylsulfonium,10-Dihydroanthracen-2-yldiphenylsulfonium, 2-[(di-p-tolyl)sulfonio]thioxanthone, 2-[(diphenyl)sulfonio]thioxanthone, 4-(9-oxo-9H-thioxanthen-2-yl)thiophenyl-9-oxo-9H-thioxanthen-2-ylphenylsulfonium, 4-[4-(4-tert-butylbenzoyl)phenylthio]phenyldi-p-tolylsulfonium, 4-[4-(4-tert-butylbenzoyl)phenylthio]phenyldiphenylsulfonium, 4-[4-(benzoyl) triarylsulfonium compounds such as 4-[4-(benzoylphenylthio)]phenyldi-p-tolylsulfonium, 4-[4-(benzoylphenylthio)]phenyldiphenylsulfonium, 5-(4-methoxyphenyl)thioanthrenenium, 5-phenylthioanthrenenium, 5-tolylthioanthrenenium, 5-(4-ethoxyphenyl)thioanthrenenium and 5-(2,4,6-trimethylphenyl)thioanthrenenium; diphenylphenacylsulfonium, diphenyl 4-nitrophenacylsulfonium, diphenylbenzylsulfonium and diphenylmethylsulfonium compounds; Examples include diarylsulfonium such as phenanthronium; monoarylsulfonium such as phenylmethylbenzylsulfonium, 4-hydroxyphenylmethylbenzylsulfonium, 4-methoxyphenylmethylbenzylsulfonium, 4-acetocarbonyloxyphenylmethylbenzylsulfonium, 4-hydroxyphenyl(2-naphthylmethyl)methylsulfonium, 2-naphthylmethylbenzylsulfonium, 2-naphthylmethyl(1-ethoxycarbonyl)ethylsulfonium, phenylmethylphenacylsulfonium, 4-hydroxyphenylmethylphenacylsulfonium, 4-methoxyphenylmethylphenacylsulfonium, 4-acetocarbonyloxyphenylmethylphenacylsulfonium, 2-naphthylmethylphenacylsulfonium, 2-naphthyloctadecylphenacylsulfonium, and 9-anthracenylmethylphenacylsulfonium; trialkylsulfonium such as dimethylphenacylsulfonium, phenacyltrhydrothiophenium, dimethylbenzylsulfonium, benzyltetrahydrothiophenium, and octadecylmethylphenacylsulfonium; and the like.

[0043] Examples of iodonium ions include diphenyliodonium, di-p-tolyliodonium, bis(4-dodecylphenyl)iodonium, bis(4-methoxyphenyl)iodonium, (4-octyloxyphenyl)phenyliodonium, bis(4-decyloxy)phenyliodonium, 4-(2-hydroxytetradecyloxy)phenylphenyliodonium, 4-isopropylphenyl(p-tolyl)iodonium, and 4-isobutylphenyl(p-tolyl)iodonium.

[0044] The cationic photopolymerization initiator (X) preferably contains, as a cation, an ammonium ion, a phosphonium ion, a sulfonium ion, or an iodonium ion, more preferably a sulfonium ion or an iodonium ion, and even more preferably a sulfonium ion.

[0045] The cationic photopolymerization initiator (X) preferably contains a salt composed of an anion represented by formula (3) or (4) and a sulfonium ion, which can further improve the heat resistance of a cured lens body formed from the lens resin composition.

[0046] [ka]

[0047] [ka]

[0048] Specific examples of the anion contained in the cationic photopolymerization initiator (X) are shown below, but the anion contained in the cationic photopolymerization initiator (X) in this embodiment is not limited to these.

[0049] [ka]

[0050] The photocationic polymerization initiator (X) can be synthesized in accordance with a known method, for example, as described in International Publication No. 2018 / 020974. Alternatively, commercially available products such as CPI-310FG (trade name, photocationic polymerization initiator, manufactured by San-Apro Co., Ltd.) may also be purchased and used.

[0051] The content of the photocationic polymerization initiator (X) is preferably 0.05 to 15 parts by mass, more preferably 0.07 to 10 parts by mass, even more preferably 0.1 to 8 parts by mass, and most preferably 0.5 to 5 parts by mass, relative to 100 parts by mass of the epoxy compound (Y). The cationic photopolymerization initiator (X) may be used singly or in combination. When a mixture of multiple types is used, the total content of each cationic photopolymerization initiator (X) is defined as the total content of the cationic photopolymerization initiator (X).

[0052] When the cationic photopolymerization initiator (X) has a high molar absorption coefficient at a wavelength of 300 to 380 nm, the content may be adjusted appropriately depending on the volume and thickness of the lens resin composition when used.

[0053] <Epoxy compound (Y)> The lens resin composition according to this embodiment contains an epoxy compound (Y) containing two or more epoxy groups in the molecule.

[0054] Examples of the epoxy compound (Y) containing two or more epoxy groups in the molecule include diethylene glycol diglycidyl ether, hexanediol diglycidyl ether, dimethylolpropane diglycidyl ether, polypropylene glycol diglycidyl ether, trimethylolpropane triglycidyl ether, trimethylolpropane triglycidyl ether, and pentaerythritol tetraglycidyl ether.

[0055] Further, examples of the epoxy compound (Y) containing two or more epoxy groups in the molecule include alicyclic epoxy resins such as 3',4'-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate and ε-caprolactone-modified 3',4'-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate.

[0056] Further, examples of the epoxy compound (Y) containing two or more epoxy groups in the molecule include bisphenol A type epoxy compounds, bisphenol F type epoxy compounds, biphenyl-phenol novolac type epoxy compounds, and epoxy resins having aromatic rings, such as epoxy compounds in which some or all of the alcoholic hydroxyl groups contained in the structure of these epoxy compounds have been epoxidized.

[0057] Examples of commercially available epoxy compounds (Y) include the EPICLON series (bisphenol A epoxy resins, manufactured by DIC Corporation) represented by EXA-850CRP, the jER series (manufactured by Mitsubishi Chemical Corporation) represented by jER828, the YD series (manufactured by Nippon Steel Chemical & Material Co., Ltd.) represented by YD-127, and TECHMORE VG3101L (trifunctional epoxy resin, manufactured by Printec Co., Ltd.).

[0058] The epoxy compound (Y) is preferably an epoxy compound having an aromatic ring, which can increase the refractive index of the cured product obtained by curing the lens resin composition, thereby improving the optical properties of the lens.

[0059] The epoxy compound (Y) is more preferably one represented by general formula (2).

[0060] [ka]

[0061] In general formula (2), R 5 , R 6 , R8 and R 9 each independently represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or a trifluoromethyl group, R 7 represents a hydrogen atom or a glycidyl group, n is the average number of repetitions and represents a real number in the range of 0 to 30.

[0062] R 5 , R 6 , R 8 and R 9 The alkyl group having 1 to 4 carbon atoms represented by R 1 ~R 4 Among the examples of alkyl groups having 1 to 18 carbon atoms represented by the formula (I), those having 1 to 4 carbon atoms can be exemplified.

[0063] R 5 , R 6 , R 8 and R 9 is preferably an alkyl group having 1 to 4 carbon atoms or a trifluoromethyl group, more preferably a methyl group or a trifluoromethyl group, and even more preferably a methyl group.

[0064] n is preferably 1 to 20, and more preferably 5 to 15. n is calculated from the weight average molecular weight calculated in polystyrene terms based on the measurement results of GPC (gel permeation chromatography).

[0065] The epoxy equivalent of the epoxy compound (Y) is not particularly limited, but is preferably 100 g / eq or more and 200 g / eq or less, more preferably 120 g / eq or more and 180 g / eq or less. The epoxy equivalent in this specification is a value measured by a method in accordance with JIS K7236.

[0066] The content of the epoxy compound (Y) in the non-volatile components of the lens resin composition of this embodiment is preferably 40% by mass or more, more preferably 50% by mass or more, and even more preferably 70% by mass or more. There is no particular upper limit to the content of the epoxy compound (Y) in the non-volatile components of the resin composition for a lens of this embodiment, but it is usually 99 mass % or less. The epoxy compound (Y) may be used singly or in combination. When a mixture of multiple epoxy compounds (Y) is used, the total content of the epoxy compound (Y) is defined as the total content of the epoxy compound (Y).

[0067] <Other ingredients> The lens resin composition according to this embodiment may contain, as necessary, a monofunctional epoxy compound (Z), an oxetane compound (W), a solvent, an adhesion promoter, a polyol compound, a polyhydric phenol compound, a sensitizer, an ion catcher, a cationic photopolymerization initiator other than the cationic photopolymerization initiator (X) (another cationic photopolymerization initiator), and the like.

[0068] (Monofunctional epoxy compound (Z)) The lens resin composition according to this embodiment preferably further contains a monofunctional epoxy compound (Z) represented by general formula (5). This can further improve the heat resistance of a cured lens product formed from the lens resin composition, and can also improve the glass adhesion of the lens resin composition.

[0069] [ka]

[0070] In general formula (5), A is selected from a single bond, an oxygen atom, and a sulfur atom; R 10 is alkylene having 1 to 8 carbon atoms, and any methylene group may be substituted with an oxygen atom.

[0071] R 10 is preferably alkylene having 1 to 4 carbon atoms, and more preferably alkylene having 1 to 2 carbon atoms.

[0072] R 10It is preferred that any methylene group is substituted with an oxygen atom.

[0073] The monofunctional epoxy compound (Z) is preferably o-phenylphenol glycidyl ether.

[0074] Examples of commercially available monofunctional epoxy compounds (Z) include OPP-EP (o-phenylphenol glycidyl ether, manufactured by Yokkaichi Synthetic Co., Ltd.) and OPP-G (o-phenylphenol glycidyl ether, manufactured by Sanko Co., Ltd.).

[0075] When the lens resin composition of this embodiment contains the monofunctional epoxy compound (Z), the content thereof is preferably 1% by mass or more, more preferably 5% by mass or more, and even more preferably 10% by mass or more, of the non-volatile components of the lens resin composition of this embodiment. When the lens resin composition of this embodiment contains the monofunctional epoxy compound (Z), the content thereof is preferably 70 mass % or less, more preferably 60 mass % or less, and even more preferably 50 mass % or less of the non-volatile components of the lens resin composition of this embodiment.

[0076] When the lens resin composition of the present embodiment contains the monofunctional epoxy compound (Z), the content thereof is preferably 1 part by mass or more, more preferably 5 parts by mass or more, and even more preferably 10 parts by mass or more, per 100 parts by mass of the epoxy compound (Y). When the lens resin composition of the present embodiment contains the monofunctional epoxy compound (Z), the content thereof is, for example, 200 parts by mass or less, preferably 150 parts by mass or less, more preferably 100 parts by mass or less, even more preferably 80 parts by mass or less, even more preferably 60 parts by mass or less, even more preferably 40 parts by mass or less, and even more preferably 25 parts by mass or less, relative to 100 parts by mass of the epoxy compound (Y).

[0077] The monofunctional epoxy compound (Z) may be used singly or in combination of two or more kinds. When two or more kinds are used in combination, the total content of the monofunctional epoxy compound (Z) is defined as the content of the monofunctional epoxy compound (Z).

[0078] (Oxetane compounds) The lens resin composition according to this embodiment preferably further contains an oxetane compound (W). This can further improve the heat resistance of a cured lens product formed from the lens resin composition, and can also improve the glass adhesion of the lens resin composition. This can also improve the curability of the resin composition.

[0079] The oxetane compound (W) is not particularly limited, and generally known compounds can be used. Specific examples of oxetane resins include oxetane, 2-methyloxetane, 3-methyloxetane, 2,2-dimethyloxetane, 3,3-dimethyloxetane, 3-ethyl-3-hydroxymethyloxetane, and biphenyl-type oxetane.

[0080] The oxetane compound (W) may be used singly or in combination of two or more kinds. When two or more kinds are used in combination, the total content of the oxetane compound (W) is defined as the total content of the oxetane compound (W).

[0081] The oxetane compound (W) is preferably a biphenyl-type oxetane compound. Specific examples of biphenyl-type oxetane include xylylene bisoxetane.

[0082] Examples of commercially available oxetane compounds (W) include Aronoxetane OXT-101 (3-ethyl-3-hydroxymethyloxetane, manufactured by Toagosei Co., Ltd.) and Aronoxetane OXT-121 (xylylene bisoxetane, manufactured by Toagosei Co., Ltd.).

[0083] When the lens resin composition of this embodiment contains an oxetane compound (W), the content thereof is preferably 0.01% by mass or more, more preferably 0.1% by mass or more, even more preferably 1% by mass or more, and still more preferably 2% by mass or more of the non-volatile components of the lens resin composition of this embodiment, from the viewpoint of improving glass adhesiveness, heat resistance, and curability, etc. When the lens resin composition of the present embodiment contains the oxetane compound (W), the content thereof is preferably 50% by mass or less, more preferably 40% by mass or less, even more preferably 30% by mass or less, even more preferably 20% by mass or less, and even more preferably 10% by mass or less.

[0084] When the lens resin composition of this embodiment contains the oxetane resin (W), the content thereof is preferably 1 part by mass or more, more preferably 5 parts by mass or more, and even more preferably 10 parts by mass or more, per 100 parts by mass of the epoxy compound (Y). When the resin composition for a lens of the present embodiment contains an oxetane resin (W), The content is, for example, 200 parts by mass or less, preferably 150 parts by mass or less, more preferably 100 parts by mass or less, even more preferably 80 parts by mass or less, even more preferably 60 parts by mass or less, even more preferably 40 parts by mass or less, even more preferably 25 parts by mass or less, and even more preferably 15 parts by mass or less.

[0085] (solvent) The solvent contained in the lens resin composition according to this embodiment is not particularly limited, but a solvent capable of dissolving each component of the lens resin composition is preferably used. Examples of such organic solvents include ketones such as acetone, ethyl methyl ketone, methyl isobutyl ketone, cyclohexanone, and cyclopentanone; aromatic hydrocarbons such as toluene, xylene, methoxybenzene, and tetramethylbenzene; glycol ethers such as diglyme, dipropylene glycol dimethyl ether, and dipropylene glycol diethyl ether; ethyl lactate, butyl lactate, propyl lactate, ethyl acetate, methyl acetoacetate, ethyl acetoacetate, methyl propionate, ethyl propionate, propyl propionate, isopropyl propionate, methyl 2-hydroxypropionate, ethyl 2-hydroxypropionate, methyl ... Examples of suitable solvents include esters such as ethyl-3-methoxypropionate, ethyl-3-methoxypropionate, ethyl-3-ethoxypropionate, propyl-3-methoxypropionate, butyl acetate, butyl cellosolve acetate, carbitol acetate, and propylene glycol monomethyl ether acetate; lactones such as α-acetolactone, β-propiolactone, γ-butyrolactone, and δ-valerolactone; alcohols such as methanol, ethanol, cellosolve, and methyl cellosolve; aliphatic hydrocarbons such as octane and decane; and petroleum solvents such as petroleum ether, petroleum naphtha, hydrogenated petroleum naphtha, and solvent naphtha.

[0086] When the lens resin composition of this embodiment contains a solvent, the content is not particularly limited as long as it is within a range that does not impair the effects of the present invention, and is usually 95% by mass or less, preferably 10 to 90% by mass. The solvent may be used alone or in combination of two or more kinds. When a mixture of two or more kinds is used, the total content of the solvents is defined as the total content of the solvents.

[0087] When the epoxy compound (Y) is in a liquid state at room temperature, coating and the like can be suitably carried out even when no solvent is blended or substantially no solvent is blended.

[0088] (adhesion imparting agent) The adhesion promoter contained in the resin composition for a lens according to this embodiment is not particularly limited, and known silane coupling agents, titanium coupling agents, etc. are usable. From the viewpoint of improving glass adhesion, it is preferable to use a silane coupling agent.

[0089] Examples of silane coupling agents include 3-chloropropyltrimethoxysilane, vinyltrichlorosilane, vinyltriethoxysilane, vinyltrimethoxysilane, vinyltris(2-methoxyethoxy)silane, 3-methacryloxypropyltrimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-mercaptopropyltrimethoxysilane, and 8-glycidyloctyltrimethoxysilane.

[0090] When the resin composition for a lens of the present embodiment contains an adhesion promoter, the content thereof is not particularly limited as long as it is within a range that does not impair the effects of the present invention, and is preferably 15% by mass or less, more preferably 10% by mass or less, even more preferably 5% by mass or less, and even more preferably 2% by mass or less of the non-volatile components of the resin composition for a lens of the present embodiment. When the resin composition for a lens of the present embodiment contains an adhesion promoter, the content thereof is not particularly limited as long as it is within a range that does not impair the effects of the present invention, and is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, and even more preferably 0.8% by mass or more of the non-volatile components of the resin composition for a lens of the present embodiment. The adhesion promoter may be used alone or in combination of two or more kinds. When a mixture of two or more kinds is used, the total content of the adhesion promoter is defined as the total content of the adhesion promoter.

[0091] (Polyol compound) The polyol compound contained in the lens resin composition according to this embodiment is not particularly limited, but is typically a polyester polyol compound containing a hydroxy group that reacts with an epoxy group under the influence of a strong acid catalyst. For example, the polyol compounds listed in Japanese Patent Publication No. 5901070 can be used.

[0092] When the lens resin composition of the present embodiment contains a polyol compound, the content thereof is not particularly limited as long as it is within a range that does not impair the effects of the present invention, and is usually 1 to 30 parts by mass, and preferably 2 to 25 parts by mass, per 100 parts by mass of the epoxy compound (Y). The polyol compound may be used alone or in combination of two or more kinds. When a mixture of two or more kinds is used, the total content of the polyol compounds is defined as the content of the polyol compounds.

[0093] The polyphenol compound contained in the lens resin composition according to this embodiment is a compound that can cure the epoxy compound to a high crosslink density by heating. For example, the polyphenol compounds listed in Japanese Patent Publication No. 5967824 can be used.

[0094] (Polyphenol compounds) When the lens resin composition of the present embodiment contains a polyhydric phenol compound, the content thereof is not particularly limited as long as it is within a range that does not impair the effects of the present invention, and is usually 3 to 40 parts by mass, preferably 4 to 30 parts by mass, and more preferably 5 to 25 parts by mass relative to 100 parts by mass of the epoxy compound (Y). The polyhydric phenol compound may be used singly or in combination of two or more kinds. When two or more kinds are used in combination, the total content of each polyhydric phenol compound is defined as the content of the polyhydric phenol compound.

[0095] (sensitizer) The sensitizer contained in the lens resin composition according to this embodiment plays a role in providing absorbed light energy to the cationic photopolymerization initiator. Examples of such sensitizers include thioxanthones and anthracene compounds having alkoxy groups at the 9th and 10th positions (9,10-dialkoxyanthracene derivatives).

[0096] When the lens resin composition of the present embodiment contains a sensitizer, the content thereof is not particularly limited as long as it is within a range that does not impair the effects of the present invention, and is preferably 30 parts by mass or less, and more preferably 20 parts by mass or less, relative to 100 parts by mass of the cationic photopolymerization initiator (X). When the lens resin composition of the present embodiment contains a sensitizer, the content thereof is not particularly limited as long as it is within a range that does not impair the effects of the present invention, and is usually 0.1 parts by mass or more relative to 100 parts by mass of the cationic photopolymerization initiator (X). The sensitizer may be used singly or in combination of two or more kinds. When two or more kinds are used in combination, the total content of the sensitizer is the sum of the contents of the individual sensitizers.

[0097] (Ion Catcher) The ion catcher contained in the lens resin composition according to this embodiment can reduce the adverse effects of ions derived from the photocationic polymerization initiator (X). For example, organoaluminum compounds or onium weak acid salt compounds that generate weak acids upon exposure to ultraviolet light can be used as the ion catcher.

[0098] When the lens resin composition of this embodiment contains an ion catcher, the content thereof is not particularly limited as long as it does not impair the effects of the present invention. In the case of organoaluminum compounds, the content is preferably 0.1 to 10 parts by mass relative to 100 parts by mass of the photocationic polymerization initiator (X). In the case of onium weak acid salt compounds, the content is preferably 0.001 to 2 parts by mass relative to 100 parts by mass of the photocationic polymerization initiator (X). Only one type of ion catcher may be used, or multiple types may be used in combination. When multiple types are used in combination, the total content of the ion catchers is the sum of the contents of the individual ion catchers.

[0099] (Other cationic photopolymerization initiators) The lens resin composition according to this embodiment may contain a cationic photopolymerization initiator other than the cationic photopolymerization initiator (X) (another cationic photopolymerization initiator). The other cationic photopolymerization initiator contained in the lens resin composition according to this embodiment is not particularly limited, and known initiators can be used.

[0100] Other cationic photopolymerization initiators include [(R 20 ) s B(Phf) 4-s ] - (In the formula, R 20 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 is an integer of 0 to 3), BF4 - , [(Rf) n PF 6-n ] - (Rf: alkyl group in which 80% or more of the hydrogen atoms are substituted with fluorine atoms, n: integer of 0 to 5), AsF6 - , SbF6 - Examples of suitable anions include those having pentafluorohydroxyantimonate or the like as an anion.

[0101] The content of the other cationic photopolymerization initiator is not particularly limited as long as the effects of the present invention are not impaired, but is preferably 50 parts by mass or less, more preferably 20 parts by mass or less, and even more preferably 10 parts by mass or less, relative to 100 parts by mass of the cationic photopolymerization initiator (X).

[0102] The other cationic photopolymerization initiators may be used singly or in combination of two or more kinds. When two or more kinds are used in combination, the total content of the other cationic photopolymerization initiators is defined as the content of the other cationic photopolymerization initiators.

[0103] (Other additives) In addition to the above components, the lens resin composition of the present embodiment may contain various additives, such as an antioxidant, a light stabilizer, a thermoplastic resin, a colorant, a thickener, an antifoaming agent, and a leveling agent, as necessary.

[0104] The lens resin composition according to this embodiment preferably further contains an antioxidant.

[0105] Examples of the antioxidant include phenol-based antioxidants, phosphorus-based antioxidants, thioether-based antioxidants, and hindered amine-based antioxidants.

[0106] The antioxidant preferably comprises a phenolic antioxidant, more preferably a hindered phenolic antioxidant.

[0107] Examples of hindered phenol-based antioxidants include 2,6-di-t-butylhydroxytoluene and pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate]. Examples of commercially available hindered phenol antioxidants include AO-20, AO-30, AO-40, AO-50, AO-60, and AO-80 in the Adeka STAB series manufactured by ADEKA Corporation.

[0108] Examples of phosphorus-based antioxidants include phosphines such as trialkylphosphine and triarylphosphine, trialkyl phosphites and triaryl phosphites. Examples of commercially available phosphorus-based antioxidants include PEP-4C, PEP-8, PEP-24G, PEP-36, HP-10, 260, 522A, 329K, 1178, 1500, 135A, and 3010 from the Adeka STAB series manufactured by ADEKA Corporation.

[0109] Examples of commercially available thioether antioxidants include AO-26, AO-412S, and AO-503A of the Adeka Stab series manufactured by ADEKA Corporation.

[0110] Examples of hindered amine antioxidants include bis(1,2,2,6,6-pentamethyl-4-piperidinyl)sebacate, methyl(1,2,2,6,6-pentamethyl-4-piperidinyl)sebacate, 2,4-bis[N-butyl-N-(1-cyclohexyloxy-2,2,6,6-tetramethylpiperidin-4-yl)amino]-6-(2-hydroxyethylamine)-1,3,5-triazine, decanedioic acid bis(2,2,6,6-tetramethyl-1-(octyloxy)-4-piperidinyl)ester, and bis(1,2,2,6,6-pentamethyl-4-piperidyl)sebacate. Examples of commercially available hindered amine antioxidants include AL-72 from the Adeka STAB series manufactured by ADEKA Corporation, and 111FDL, 123, 144, 152, 292, and 5100 from the TINUVIN series manufactured by BASF.

[0111] When two or more antioxidants are used in combination, it is preferable to use a phenolic antioxidant in combination with a hindered amine antioxidant, and a phenolic antioxidant in combination with a thioether antioxidant.

[0112] When the lens resin composition of this embodiment contains an antioxidant, the content thereof may be set appropriately depending on the purpose. From the viewpoint of obtaining a cured product with little coloration, the content thereof is preferably 0.01 parts by mass or more, more preferably 0.1 parts by mass or more, relative to 100 parts by mass of the total amount of the epoxy compound (Y), the monofunctional epoxy compound (Z), and the oxetane compound (W); and from the viewpoint of obtaining a resin composition with excellent curability, the content thereof is preferably 5 parts by mass or less, more preferably 1 part by mass or less.

[0113] The resin composition for a lens according to this embodiment preferably further contains a light stabilizer.

[0114] The light stabilizer according to this embodiment preferably includes a hindered amine light stabilizer. Examples of the hindered amine light stabilizer include compounds exemplified as the hindered amine antioxidant, such as bis(1,2,2,6,6-pentamethyl-4-piperidyl) sebacate, and commercially available products.

[0115] When the lens resin composition of this embodiment contains a light stabilizer, the content thereof is preferably 0.01 parts by mass or more, more preferably 0.05 parts by mass or more, and preferably 1 part by mass or less, more preferably 0.5 parts by mass or less, relative to 100 parts by mass as the total amount of the epoxy compound (Y), the monofunctional epoxy compound (Z), and the oxetane compound (W).

[0116] <Manufacturing method> The lens resin composition of this embodiment can be obtained by mixing and stirring the above-mentioned components by a conventional method. Alternatively, the components may be dispersed and mixed using a dispersing machine such as a dissolver, homogenizer, or triple-roll mill, as needed. After mixing, the components may be further filtered using a mesh or membrane filter.

[0117] <Physical properties> The viscosity of the lens resin composition of this embodiment can be measured, for example, by an E-type viscometer. The viscosity of the lens resin composition of this embodiment, when measured using an E-type viscometer at a temperature of 25°C and a rotation speed of 2.5 rpm, is preferably 100 mPa·s or more and 5000 mPa·s or less, more preferably 200 mPa·s or more and 3000 mPa·s or less, and even more preferably 500 mPa·s or more and 2000 mPa·s or less.

[0118] The lens resin composition of this embodiment is applied to a glass plate in a thickness of 250 μm, and the wavelength is 365 nm, the irradiation intensity is 150 mW / cm, and the cumulative irradiation amount is 3000 mJ / cm. 2 and then heated in a nitrogen atmosphere at 120°C for 30 minutes. The cure shrinkage of the lens cured product (α) obtained is preferably 1.0% or more and 5.0% or less, more preferably 1.2% or more and 4.0% or less, and even more preferably 1.5% or more and 3.0% or less. When the cure shrinkage percentage of the lens cured product (α) is within the above range, the dimensional accuracy during lens production can be improved.

[0119] The cure shrinkage of the lens cured product (α) can be determined by the following procedure. First, the specific gravity d1 of the lens resin composition is determined in accordance with JIS Z 8804:2012 (Method for measuring density and specific gravity of liquids). If the lens resin composition contains volatile components, the specific gravity of the non-volatile components excluding these is determined. Next, the specific gravity d2 of the lens cured product (α) is determined in accordance with JIS Z 8807:2012 (Method for measuring density and specific gravity of solids). Using the determined specific gravity value, the cure shrinkage is calculated according to the following formula. Curing shrinkage rate (%)=(1-d1 / d2)×100

[0120] In the lens resin composition of this embodiment, the refractive index of the lens cured product (α) obtained under the above conditions is preferably 1.57 or more, more preferably 1.58 or more, and even more preferably 1.59 or more. When the refractive index of the lens cured product (α) is within the above range, the optical properties of the lens can be improved.

[0121] The refractive index of the lens cured product (α) can be measured with an Abbe refractometer.

[0122] The resin composition for a lens of this embodiment preferably has a light transmittance T1 in the thickness direction of the cured product for a lens (α) obtained under the above conditions of 80% or more. When the light transmittance of the lens cured product (α) is within the above range, a lens with higher transparency can be produced.

[0123] The light transmittance T1 in the thickness direction of the lens cured product (α) can be measured by a transmission method using an ultraviolet-visible-near-infrared spectrophotometer at a measurement wavelength of 400 nm.

[0124] The lens resin composition of this embodiment is such that the rate of change after heating (125°C for 168 hours) in light transmittance in the thickness direction of the lens cured product (α) obtained under the above conditions is preferably 10% or less, more preferably 5% or less, and even more preferably 2% or less. When the rate of change in light transmittance after heating of the lens cured product (α) is within the above range, a lens with better heat resistance can be produced.

[0125] The rate of change in light transmittance in the thickness direction of the lens cured product (α) after heating (125°C for 168 hours) can be determined by the following procedure. First, the lens cured product (α) is heated for 168 hours in an oven set to 125°C in an air atmosphere. Thereafter, the light transmittance in the thickness direction is measured under the above conditions to obtain the post-heating light transmittance T2, which is calculated using the following formula: Change in light transmittance after heating (125℃ 168 hours) (%) =(T1-T2) / T1×100

[0126] In the lens resin composition of this embodiment, the cured product (α) obtained under the above conditions preferably satisfies the following requirements (A) to (D). (A) The cure shrinkage of the cured product is 1.0% or more and 5.0% or less. (B) The refractive index of the cured product is 1.57 or more. (C) The cured product has a light transmittance in the thickness direction of 80% or more. (D) The change in light transmittance in the thickness direction of the cured product after heating (125°C for 168 hours) is 10% or less. When the lens cured product (α) satisfies the above requirements (A) to (D), a lens having dimensional precision, optical properties, transparency, and heat resistance can be produced.

[0127] <Application> The resin composition for a lens of this embodiment is suitably used for a wafer-level lens.

[0128] A wafer-level lens is a lens that is manufactured by simultaneously creating multiple lenses on a wafer-shaped resin (wafer-level lens array) and then cutting it into pieces. Fig. 1 is a plan view showing an example of the configuration of a wafer-level lens array having a plurality of wafer-level lenses. As shown in Fig. 1, the wafer-level lens array 1 includes a substrate 2 and a plurality of lenses 10 arranged on the substrate 2. The plurality of lenses 10 are formed so as to be arranged one-dimensionally or two-dimensionally on the substrate 2. The lenses 10 formed on the wafer-level lens array 1 are then cut into individual lenses.

[0129] Therefore, wafer-level lenses have the advantage of being able to produce several hundred lenses at a time, resulting in excellent production efficiency.

[0130] Another advantage of wafer-level lenses is that they can be used to create thin, compact lenses, something that injection molding has limitations in. Wafer-level lenses typically have a diameter of about 1 to 10 mm and a thickness of about 100 to 2000 μm, and taking advantage of this size, wafer-level lenses are ideal for use in cameras in electronic devices such as smartphones, tablet devices, and laptops.

[0131] The resin composition for a lens of this embodiment can form a cured product for a lens that has a low cure shrinkage rate, a high refractive index, a high light transmittance, and high heat resistance, and is therefore suitable for use in wafer-level lenses, which require thinness and small size.

[0132] [Cured product for lenses] The cured product for a lens according to this embodiment can be obtained by curing the above-described resin composition for a lens.

[0133] The cure shrinkage of the cured product for a lens according to this embodiment is preferably 1.0% or more and 5.0% or less, more preferably 1.2% or more and 4.0% or less, and even more preferably 1.5% or more and 3.0% or less. The cure shrinkage can be determined by the procedure described above as the procedure for measuring the cure shrinkage of the cured product for a lens (α).

[0134] The refractive index of the cured product for a lens according to this embodiment is preferably 1.57 or more, more preferably 1.58 or more, and even more preferably 1.59 or more. The refractive index can be determined by the procedure described above for measuring the refractive index of the cured product for a lens (α).

[0135] The light transmittance in the thickness direction of the cured product for a lens according to this embodiment is preferably 80% or more. The light transmittance can be determined by the procedure described above as the procedure for measuring the light transmittance of the cured product for a lens (α).

[0136] The rate of change in light transmittance in the thickness direction of the cured product for a lens according to this embodiment after heating (125°C for 168 hours) is preferably 10% or less, more preferably 5% or less, and even more preferably 2% or less. The rate of change in light transmittance after heating (125°C for 168 hours) can be determined by the procedure described above for measuring the rate of change in light transmittance after heating (125°C for 168 hours) of the cured product for a lens (α).

[0137] The cured product for lenses according to this embodiment has low cure shrinkage, a high refractive index, high light transmittance, and high heat resistance, and is therefore suitable for use in wafer-level lenses, which are required to be thin and small.

[0138] [lens] The lens according to this embodiment includes the above-described cured product for a lens.

[0139] The lens according to this embodiment can be manufactured by, for example, imprint molding. Imprint molding is a processing technique in which a lens resin composition is sandwiched between lens molding dies and a pattern is transferred. The lens resin composition sandwiched between the lens molding dies is cured by heating or light irradiation.

[0140] For light irradiation, for example, a mercury lamp, a xenon lamp, a carbon arc lamp, a metal halide lamp, sunlight, an electron beam source, a laser light source, an LED light source, or the like is used, and the cumulative irradiation amount is, for example, 500 to 5000 mJ / cm 2 This can be done by irradiating in a range where

[0141] The lens resin composition (lens cured product) that has been sandwiched between lens molding dies and cured may be used as a lens as is, but the lens cured product may also be laminated with other materials. An example of another material to be laminated with the lens cured product is glass. Glass is available in a wide variety of types, and glass with a high refractive index can be selected, making it suitable as a lens material that requires high optical properties. Glass also has the advantage of excellent heat resistance. Alternatively, resin may be used, which has excellent processability and is suitable for forming lenses easily and inexpensively.

[0142] Furthermore, when a wafer-level molding die is used as the lens molding die, a wafer-level lens array is obtained, and the obtained wafer-level lens array is cut into individual lenses. Wafer-level lens arrays are as described above.

[0143] The lens according to this embodiment has a low cure shrinkage rate, a high refractive index, a high light transmittance, and high heat resistance, and is therefore suitable for use as a wafer-level lens for which thinness and small size are required.

[0144] The diameter of the wafer level lens is usually 1 to 10 mm, preferably 1 to 5 mm, and the thickness of the wafer level lens is usually 100 to 2000 μm, preferably 100 to 1000 μm.

[0145] Wafer-level lenses are suitable for use in cameras in electronic devices such as smartphones, tablet computers, and laptop computers.

[0146] Although the embodiments of the present invention have been described above, these are merely examples of the present invention, and various other configurations can also be adopted. Furthermore, the present invention is not limited to the above-described embodiment, and modifications and improvements within the scope of achieving the object of the present invention are included in the present invention. [Example]

[0147] Hereinafter, embodiments of the present invention will be specifically described based on examples, but the embodiments of the present invention are not limited to these examples.

[0148] <Preparation of Lens Resin Composition>

[0149] The raw materials listed in Table 1 were stirred and mixed while being heated at 50°C until they became homogeneous, thereby obtaining a resin composition for a lens.

[0150] The raw materials listed in Table 1 are as follows:

[0151] Photocationic polymerization initiator (X) Triarylsulfonium tetrakispentafluorophenyl gallate, manufactured by San-Apro Co., Ltd., product name: CPI-310FG

[0152] Other cationic photoinitiators Photocationic polymerization initiator represented by the following formula, manufactured by San-Apro Co., Ltd., product name: CPI-210S

[0153] [ka]

[0154] Epoxy compounds (Y) Bisphenol A epoxy resin, manufactured by DIC Corporation, product name: EXA-850CRP, epoxy equivalent: 158-168g / eq

[0155] Monofunctional epoxy compounds (Z) o-Phenylphenol glycidyl ether, manufactured by Yokkaichi Chemical Co., Ltd., product name: OPP-EP

[0156] Oxetane compounds (W) Biphenyl-type oxetane compound, xylylene bisoxetane, manufactured by Toagosei Co., Ltd., product name: Aron Oxetane OXT-121

[0157] Adhesion promoter Silane coupling agent, 3-glycidoxypropyltrimethoxysilane, manufactured by Shin-Etsu Chemical Co., Ltd., product name: KBM-403

[0158] Antioxidants Phenolic antioxidant, pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], manufactured by ADEKA Corporation, product name: ADK STAB AO-60

[0159] Light stabilizer Hindered amine light stabilizer, bis(1,2,2,6,6-pentamethyl-4-piperidyl) sebacate, manufactured by ADEKA Corporation, product name: ADK STAB LA-72

[0160] <Viscosity> The viscosity of the lens resin composition was measured using an E-type viscometer (TVE-25L, manufactured by Toki Sangyo Co., Ltd.) at a temperature of 25°C and a rotation speed of 2.5 rpm. The cone plate was selected appropriately from 1°34' x R24, 3° x R14, or 3° x R9.7 depending on the viscosity of the sample. The results are shown in Table 1.

[0161] <Preparation of cured material for lenses> A glass substrate (9.0 × 10.0 × 0.7 mm, Eagle-XG, manufactured by Corning) was immersed in Novec (registered trademark) 1720 (a fluorosilane-based release agent, manufactured by 3M Corporation), heated at 100°C for 25 minutes under a nitrogen atmosphere, and rinsed with Novec (registered trademark) 7100 (a fluorine-based solvent, manufactured by 3M Corporation) to obtain a release-treated glass substrate. The lens resin composition was dropped onto a release-treated glass substrate, and the substrate was sandwiched between the release-treated glass substrates via a 250 μm-thick silicone spacer and fixed with clips. An electrodeless lamp (H bulb) was used to illuminate the substrate, with an irradiation intensity of 150 mW / cm at a wavelength of 365 nm and an accumulated irradiation dose of 3000 mJ / cm. 2 The resin composition for lenses was cured by UV exposure so that the temperature became 100°C. Subsequently, the cured resin composition for a lens was released from the glass substrate and heated at 120°C for 30 minutes in a nitrogen atmosphere to obtain a cured product for a lens.

[0162] <Cure shrinkage rate> First, the specific gravity d1 of the resin composition for a lens was determined in accordance with JIS Z 8804:2012 (Method for measuring density and specific gravity of liquids). (Note that when the resin composition for a lens contains volatile components, the specific gravity of the non-volatile components excluding these is determined, but the resin composition of this example does not contain volatile components.) Next, the specific gravity d2 of the cured product for lens was determined in accordance with JIS Z 8807:2012 (Method for measuring density and specific gravity of solids). Using the determined specific gravity value, the cure shrinkage was calculated according to the following formula. The results are shown in Table 1. Curing shrinkage rate (%)=(1-d1 / d2)×100

[0163] <Refractive index measurement> The refractive index of the cured lens material was measured using an Abbe refractometer (DR-M2, manufactured by Atago Co., Ltd.). The interference filter was RE-3520 (589 nm, D-line, manufactured by Atago Co., Ltd.) and the intermediate liquid was RE-1196 (monobromonaphthalene, manufactured by Atago Co., Ltd.). The sample temperature was set to 25°C. The results are shown in Table 1.

[0164] <Light transmittance> The light transmittance in the thickness direction of the cured lens product was measured under the following conditions to obtain the light transmittance T1. The measurement was performed by attaching the cured lens product to an integrating sphere, with the light incident surface being an arbitrary surface. (Measurement conditions) Measurement equipment: UH4150 (Hitachi High-Tech Science ultraviolet-visible near-infrared spectrophotometer) Measurement method: Transmission method Measurement wavelength: 400 nm Reference: Atmosphere Detector: Integrating sphere / photomultiplier tube (200nm~850nm) Integrating sphere: PbS (850nm~2600nm)

[0165] <Change in light transmittance after heating (125°C for 168 hours)> First, the lens cured product was heated in an oven set to 125°C in an air atmosphere for 168 hours. After that, the light transmittance in the thickness direction was measured under the above conditions to obtain the post-heating light transmittance T2, which was calculated using the following formula. The results are shown in Table 1. Change in light transmittance after heating (125℃ 168 hours) (%) =(T1-T2) / T1×100

[0166] <Evaluation of glass adhesion> A glass substrate (7.0 × 7.0 × 0.21 mm, D263T ECO, manufactured by SCHOTT) was immersed in Novec (registered trademark) 1720 (a fluorosilane-based release agent, manufactured by 3M Corporation), heated at 100°C for 25 minutes under a nitrogen atmosphere, and rinsed with Novec (registered trademark) 7100 (a fluorine-based solvent, manufactured by 3M Corporation) to obtain a release-treated glass substrate. The lens resin composition was dropped onto a release-treated glass substrate, and the substrate was sandwiched between two glass substrates (7.0 × 7.0 × 0.21 mm, D263T ECO, manufactured by SCHOTT) that had not been subjected to release treatment via a 250 μm-thick silicone spacer, and then fixed in place with clips. The amount of lens resin composition dropped was adjusted so that the diameter of the wetted and spread resin composition was approximately 5 mm. In contrast, when using an electrodeless lamp (H bulb), the irradiation intensity at 365 nm wavelength is 150 mW / cm and the cumulative irradiation amount is 3000 mJ / cm 2 The resin composition for a lens was cured by UV exposure so that the resin composition for a lens was cured. Subsequently, the release-treated glass substrate was released from the cured resin composition for a lens, and the resin composition was heated at 120°C for 30 minutes in a nitrogen atmosphere to obtain a laminate of the cured product for a lens and the glass substrate (resin diameter 5 mm). Furthermore, a laminate of a cured product for a lens and a glass substrate (resin diameter 40 mm) was obtained by the same procedure as above, except that the amount of resin composition for a lens dropped was adjusted so that the diameter of the resin composition was 40 mm. At this time, the laminates were evaluated as follows: A: those in which no peeling was observed at the interface between the lens cured product and the glass substrate; B: those in which no peeling occurred but the glass substrate was noticeably deformed; and C: those in which the resin easily peeled off from the substrate. The results are shown in Table 1.

[0167] [Table 1]

[0168] The Examples had a smaller rate of change in light transmittance after heating than the Comparative Examples. This means that coloration due to heating was suppressed. Furthermore, the cure shrinkage, refractive index, and light transmittance of the Examples were at high levels comparable to those of the Comparative Examples. From these findings, it can be seen that the lens resin composition of this embodiment combines low cure shrinkage, a high refractive index, high light transmittance, and high heat resistance.

[0169] Furthermore, when comparing the examples, it is found that glass adhesion is improved when one or more compounds selected from the group consisting of monofunctional epoxy compounds (Z), oxetane compounds, and adhesion promoters are included.

[0170] This application claims priority based on Japanese Patent Application No. 2022-000161, filed on January 4, 2022, the disclosure of which is incorporated herein in its entirety. [Explanation of symbols]

[0171] 1 Wafer lens array 2 boards 10 Lenses

Claims

1. a cationic photopolymerization initiator (X) containing a salt formed from an anion represented by general formula (1) and a cation; an epoxy compound (Y) containing two or more epoxy groups in the molecule; A resin composition for a lens comprising: The epoxy compound (Y) is represented by general formula (2), The lens resin composition was applied to a glass plate to a thickness of 250 μm, and the wavelength was 365 nm, the irradiation intensity was 150 mW / cm, and the cumulative irradiation amount was 3000 mJ / cm. ２ and then heated in a nitrogen atmosphere at 120°C for 30 minutes, the cured product of which satisfies the requirement (B) below (however, this does not include energy ray-curable compositions containing an acid generator including an onium gallate salt represented by the following general formula (I) and an onium phosphate salt represented by the following general formula (II) and a cationically polymerizable compound). (B) The refractive index of the cured product is 1.57 or more. 【Chemical Formula 1】 (In general formula (1), R １ ~R ４ each independently represents an alkyl group having 1 to 18 carbon atoms or an aryl group having 6 to 14 carbon atoms. 【Chemistry 2】 (In the general formula (2), R ５ , R ６ , R ８ and R ９ each independently represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or a trifluoromethyl group, R ７ each independently represents a hydrogen atom or a glycidyl group, n is the average number of repetitions and represents a real number ranging from 0 to 30. [(R ５ ) ｎ＋１ -E] ＋ [(R １ )(R ２ )(R ３ )(R ４ )Ga] － (I) [In formula (I), R １ ~R ４ are each independently an alkyl group having 1 to 18 carbon atoms or Ar, provided that at least one is Ar; Ar is an aryl group having 6 to 14 carbon atoms (not including the number of carbon atoms of the following substituents), in which some of the hydrogen atoms in the aryl group are replaced by an alkyl group having 1 to 18 carbon atoms, an alkyl group having 1 to 8 carbon atoms substituted with a halogen atom, an alkenyl group having 2 to 18 carbon atoms, an alkynyl group having 2 to 18 carbon atoms, an aryl group having 6 to 14 carbon atoms, a nitro group, a hydroxyl group, a cyano group, or -OR ６ an alkoxy group or an aryloxy group represented by R ７ an acyl group represented by CO-, R ８ an acyloxy group represented by COO-; ９ an alkylthio group or an arylthio group represented by the formula: １０ R １１ or a halogen atom, R ６ ~R ９ is an alkyl group having 1 to 8 carbon atoms or an aryl group having 6 to 14 carbon atoms, R １０ and R １１ is a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, or an aryl group having 6 to 14 carbon atoms; E represents an element of valence n from Groups 15 to 17 (IUPAC notation), n is an integer from 1 to 3, R ５ is an organic group bonded to E, and R ５ The number of R is n+1, and (n+1) R ５ may be the same or different, and two or more R ５ are directly connected to each other or -O-, -S-, -SO-, -SO ２ A ring structure containing the element E may be formed via -, -NH-, -CO-, -COO-, -CONH-, an alkylene group, or a phenylene group.] [(R ５ ) ｎ＋１ -E] ＋ [(Rf) ｂ PF ６－ｂ ] － (II) In formula (II), Rf represents an alkyl group in which 80% or more of the hydrogen atoms are substituted with fluorine atoms. b represents the number of Rf and is an integer of 1 to 5. The b Rfs may be the same or different. R ５ The definitions of E and n are the same as those in general formula (I).

2. The resin composition for lenses according to claim 1, The resin composition for lenses has an epoxy equivalent of the epoxy compound (Y) of 100 g / eq or more and 200 g / eq or less.

3. The resin composition for lenses according to claim 1 or 2, A resin composition for a lens, wherein the content of the epoxy compound (Y) is 40 mass % or more of the non-volatile components of the resin composition for a lens.

4. The resin composition for lenses according to claim 1 or 2, The lens resin composition, wherein the cationic photopolymerization initiator (X) contains an anion represented by either formula (3) or (4). 【Chemistry 3】 【Chemistry 4】

5. The resin composition for lenses according to claim 1 or 2, The lens resin composition, wherein the cationic photopolymerization initiator (X) contains a sulfonium ion as a cation.

6. The resin composition for lenses according to claim 1 or 2, A resin composition for a lens, further comprising a monofunctional epoxy compound (Z) represented by general formula (5): 【Chemistry 5】 (In the general formula (5), A is selected from a single bond, an oxygen atom, and a sulfur atom; R １０ is alkylene having 1 to 8 carbon atoms, and any methylene group may be substituted with an oxygen atom.

7. The resin composition for lenses according to claim 6, The resin composition for lenses, wherein the monofunctional epoxy compound (Z) is o-phenylphenol glycidyl ether.

8. The resin composition for lenses according to claim 1 or 2, The resin composition for a lens further comprises an oxetane compound (W).

9. The resin composition for lenses according to claim 8, The resin composition for a lens, wherein the oxetane compound (W) is a biphenyl-type oxetane compound.

10. The resin composition for lenses according to claim 1 or 2, The resin composition for a lens has a viscosity of 100 mPa·s or more and 5000 mPa·s or less when measured with an E-type viscometer at a temperature of 25°C and a rotation speed of 2.5 rpm.

11. The resin composition for lenses according to claim 1 or 2, The lens resin composition was applied to a glass plate to a thickness of 250 μm, and the wavelength was 365 nm, the irradiation intensity was 150 mW / cm, and the cumulative irradiation amount was 3000 mJ / cm. ２ and then heated in a nitrogen atmosphere at 120°C for 30 minutes, the cured product of which satisfies the following requirements (A) and (C) to (D): (A) The cure shrinkage of the cured product is 1.0% or more and 5.0% or less. (C) The cured product has a light transmittance in the thickness direction of 80% or more. (D) The change in light transmittance in the thickness direction of the cured product after heating (125°C for 168 hours) is 10% or less.

12. The resin composition for lenses according to claim 1 or 2, A resin composition for lenses used in wafer-level lenses.

13. A cured product for a lens obtained by curing the resin composition for a lens according to claim 1 or 2.

14. A lens comprising the cured product for lenses according to claim 13.

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