Resin composition for lens, cured product for lens, and lens

Abstract

This resin composition for a lens comprises: a photocationic polymerization initiator (X) containing a salt formed from an anion represented by general formula (1) and a cation; an epoxy compound (Y) containing at least two epoxy groups in a molecule; and a stabilizer having a base dissociation constant pKb of at least 6.0.

Description

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

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

[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. It is also known that epoxy resin is used as a material for the lenses. Examples of such techniques include those described in Patent Documents 1 to 3.

[0004] Patent Document 1 describes a molding process and a silicone encapsulant composition suitable for use therein, which comprises the steps of: 1) heating a mold having a mold cavity at a temperature ranging from 100°C to 200°C; 2) supplying an amount of a silicone composition containing a mold release agent to an assembly, the composition having a viscosity ranging from 50 cps to 3,000 cps at the operating temperature of the process, and preventing the silicone encapsulant composition from flowing back out of the assembly; and 3) injecting the silicone composition from the assembly into the mold cavity through a gate, wherein 3) maintaining the silicone composition at 1,000 psi to 10,000 psi for a time sufficient to prevent the silicone composition from flowing out of the mold cavity; and 5) curing the product of step 4).

[0005] Furthermore, Patent Document 2 discloses an active energy ray-curable resin composition for Fresnel lenses, which has excellent substrate adhesion to plastic substrates, is resistant to chipping or cracking due to external forces while maintaining a high elastic modulus, and exhibits excellent shape retention over a wide temperature range, and which aims to obtain a Fresnel lens sheet using the active energy ray-curable resin composition for Fresnel lenses. The active energy ray-curable resin composition contains as essential components: an epoxy (meth)acrylate (a) having two or more (meth)acryloyl groups obtained by reacting an epoxy resin having a cyclic structure and an epoxy equivalent of 450 g / eq or more with (meth)acrylic acid; a trifunctional (meth)acrylate (b) having a specific structure; a (meth)acrylate (c) which is a (meth)acrylate of an aliphatic polyhydric alcohol having a propylene oxide structure and two or more hydroxyl groups and has a molecular weight of 700 or less; and a monofunctional (meth)acrylate (d) having a cyclic structure.

[0006] Furthermore, Patent Document 3 discloses a curable composition for lenses, which contains at least an alicyclic epoxy compound (A) having a specific structure, a cationic polymerization initiator (B), and a polysiloxane (C) having a specific structure, with the aim of providing a curable composition that is excellent in mold transfer accuracy and that can form lenses that are excellent in heat resistance and optical properties, and which contains 0.01 to 5% by weight of the polysiloxane (C) relative to the total amount (100% by weight) of the curable composition.

[0007] JP-T-2008-545553 A JP-A-2003-131004 A JP-A-2019-189874 A

[0008] Conventional lens materials have room for improvement in terms of achieving the various properties required of lenses, such as optical properties and heat resistance.

[0009] The present invention provides a resin composition for lenses that can form a cured product for lenses having an improved balance of high refractive index, high light transmittance, high heat resistance, and bleed-out resistance. Another object of the present invention is to provide a cured product for lenses and a lens having an improved balance of high refractive index, high light transmittance, high heat resistance, and bleed-out resistance.

[0010] 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, an epoxy compound, and a specific stabilizer in combination, thereby completing the present invention.

[0011] 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.

[0012] [1] A lens resin composition comprising: a photocationic polymerization initiator (X) containing a salt formed from an anion represented by the following general formula (1) and a cation; an epoxy compound (Y) containing two or more epoxy groups in its molecule; and a stabilizer having a base dissociation constant pKb of 6.0 or more as measured by the <Method for Measuring Base Dissociation Exponent pKb> below. <Method for Measuring Base Dissociation Exponent pKb> 0.1 g of the stabilizer is dissolved in 100 g of an 80 mass % aqueous solution containing methanol, and the solution is titrated with a 3N-HCl aqueous solution while measuring the pH using a pH meter to obtain a pH titration curve. The obtained pH titration curve is used to calculate the pKb value by a graphical method. [2] The lens resin composition according to the above [1], wherein the stabilizer contains one or more partial structures selected from the group consisting of a partial structure represented by the following general formula (6) and a partial structure represented by the following general formula (7): (In the above 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. (In the above general formula (6), R ａ represents an alkyl group having 1 to 18 carbon atoms or an aryl group having 6 to 14 carbon atoms. (In the above general formula (7), O. represents an oxyl group.) [3] The lens resin composition according to the above [1] or [2], wherein the base dissociation constant pKb of the stabilizer is 12.0 or less. [4] A lens resin composition comprising: a photocationic polymerization initiator (X) containing a salt formed from an anion represented by the following general formula (1) and a cation; an epoxy compound (Y) containing two or more epoxy groups in the molecule; and a stabilizer containing one or more partial structures selected from the group consisting of a partial structure represented by the following general formula (6) and a partial structure represented by the following general formula (7). (In the above 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. (In the above general formula (6), R ａ represents an alkyl group having 1 to 18 carbon atoms or an aryl group having 6 to 14 carbon atoms. (In the above general formula (7), O. represents an oxyl group.) [5] The lens resin composition according to any one of the above [1] to [4], wherein the content of the stabilizer is 0.01 parts by mass or more and 5.0 parts by mass or less per 100 parts by mass of the epoxy compound (Y). [6] The lens resin composition according to any one of the above [1] to [5], wherein the epoxy compound (Y) is represented by the following general formula (2): (In the above 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, and n is the average repeat number and represents a real number in the range of 0 to 30.) [7] The lens resin composition according to any one of [1] to [6] above, wherein the cationic photopolymerization initiator (X) contains, as an anion, at least one anion selected from the group consisting of an anion represented by the following formula (3) and an anion represented by the following formula (4): [8] The lens resin composition according to any one of the above [1] to [7], wherein the photocationic polymerization initiator (X) contains a sulfonium ion as a cation. [9] The lens resin composition according to any one of the above [1] to [8], further comprising a monofunctional epoxy compound (Z) represented by the following general formula (5): (In the above general formula (5), A is selected from a single bond, an oxygen atom, and a sulfur atom, and R １０ is alkylene having 1 to 8 carbon atoms, and any methylene group may be substituted with an oxygen atom.)

[10] The lens resin composition according to [9] above, wherein the monofunctional epoxy compound (Z) comprises o-phenylphenol glycidyl ether.

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

[10] above, wherein the lens resin composition further comprises an oxetane compound (W).

[12] The lens resin composition according to

[11] above, wherein the oxetane compound (W) comprises a biphenyl-type oxetane compound.

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

[12] above, wherein the lens resin composition 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.

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

[13] above, wherein the resin composition for a lens is applied to a glass substrate in a thickness of 250 μm, and the applied composition is irradiated at a wavelength of 365 nm, an irradiation intensity of 500 mW / cm, and an accumulated irradiation amount of 6000 mJ / cm ２ and then heated in a nitrogen atmosphere at 120°C for 30 minutes, the cured product having a refractive index of 1.55 or more.

[15] The lens resin composition according to any one of [1] to

[14] above, wherein the lens resin composition is applied to a glass substrate to a thickness of 250 μm, and the cured product is exposed to UV light at a wavelength of 365 nm, an irradiation intensity of 500 mW / cm, and an accumulated irradiation dose of 6000 mJ / cm. ２and heating in a nitrogen atmosphere at 120°C for 30 minutes, the cured product obtained has a light transmittance in the thickness direction of 70% or more as measured using an ultraviolet-visible-near-infrared spectrophotometer under the following (measurement conditions): (Measurement conditions) Measurement method: Transmission method Measurement wavelength: 400 nm Reference: Air Detector: Integrating sphere / photomultiplier tube (200 nm to 850 nm) Integrating sphere: PbS (850 nm to 2600 nm)

[16] A lens resin composition according to any of the above [1] to

[15] , wherein the lens resin composition is applied to a glass substrate to a thickness of 250 μm, and the applied light is exposed to UV light at a wavelength of 365 nm, an irradiation intensity of 500 mW / cm, and an accumulated irradiation amount of 6000 mJ / cm. ２ A resin composition for a lens, wherein the cured product obtained by UV exposure under the conditions of (1) above and heating under a nitrogen atmosphere at 120°C for 30 minutes has a light transmittance in the thickness direction of 70% or more, as measured using an ultraviolet-visible-near-infrared spectrophotometer under the following (measurement conditions), after the following (heat resistance test). (Measurement conditions) Measurement method: Transmission method Measurement wavelength: 400 nm Reference: Air Detector: Integrating sphere / photomultiplier tube (200 nm to 850 nm) Integrating sphere: PbS (850 nm to 2600 nm) (Heat resistance test) The cured product is heated in an oven set at 125°C under an air atmosphere for 168 hours.

[17] The resin composition for a lens according to any one of the above [1] to

[16] , which is used for a wafer-level lens.

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

[17] .

[19] A lens comprising the cured product for a lens according to the above

[18] .

[0013] The lens resin composition of the present invention, having the above-mentioned configuration, can form a cured product having an improved performance balance of high refractive index, high light transmittance, high heat resistance, and bleed-out resistance. Furthermore, the lens cured product of the present invention is obtained by curing the lens resin composition described above, and therefore has an improved performance balance of high refractive index, high light transmittance, high heat resistance, and bleed-out resistance. Furthermore, the lens of the present invention includes the lens cured product described above, and therefore has an improved performance balance of high refractive index, high light transmittance, high heat resistance, and bleed-out resistance.

[0014] 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.

[0015] 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, when a group such as an alkyl group "has a substituent," it means that a hydrogen atom present in the structure has been substituted with a substituent, unless otherwise specified. 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 substituted with a phenyl group is considered to be an alkyl group with two carbon atoms. In this embodiment, non-volatile components refer to the components of the resin composition for lenses excluding volatile components such as solvents.

[0016] [Lens Resin Composition] The lens resin composition of the first embodiment of the present invention comprises a cationic photopolymerization initiator (X) containing a salt formed from an anion represented by the following general formula (1) and a cation; an epoxy compound (Y) containing two or more epoxy groups in the molecule; and a stabilizer having a base dissociation constant pKb of 6.0 or more as measured by the <Method for Measuring Base Dissociation Exponent pKb> below. <Method for Measuring Base Dissociation Exponent pKb> 0.1 g of the stabilizer is dissolved in 100 g of an 80 mass % aqueous solution containing methanol, and this solution is titrated with a 3N-HCl aqueous solution while measuring the pH using a pH meter to obtain a pH titration curve. The pKb value is calculated by a graphical method using the obtained pH titration curve.

[0017]

[0018] 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.

[0019] The lens resin composition of the first embodiment of the present invention can form a cured product with an improved balance of performance, including a high refractive index, high light transmittance, high heat resistance, and bleed-out resistance. Suppressing the occurrence of bleed-out during UV curing and heating can also suppress the generation of foreign matter. While the detailed mechanism is unclear, it is presumed that photocationic polymerization initiators containing anionic gallium generate almost no strong acid components even when heated, thereby suppressing heat-induced deterioration such as coloration and the generation of foreign matter. Furthermore, photocationic polymerization initiators containing anionic gallium can suppress adverse effects on various performance characteristics, such as high refractive index, high light transmittance, and high heat resistance, while exhibiting polymerization performance at the level of the prior art. Furthermore, a stabilizer with a base dissociation constant pKb of 6.0 or more, as determined by the above-mentioned <Method for Measuring the Base Dissociation Exponent pKb>, when used in combination with a photocationic polymerization initiator containing anionic gallium that generates almost no strong acid components even when heated, can prevent bonding with strong acid components and suppress bleed-out due to changes in compatibility.

[0020] From the viewpoint of achieving a further improved performance balance of high refractive index, high light transmittance, high heat resistance, coloration resistance, and bleed-out resistance, the base dissociation constant pKb of the stabilizer in the lens resin composition of the first embodiment of the present invention is 6.0 or more, more preferably 7.0 or more, even more preferably 8.0 or more, even more preferably 9.0 or more, and still more preferably 10.0 or more, and is preferably 15.0 or less, more preferably 14.0 or less, even more preferably 13.0 or less, even more preferably 12.0 or less, and still more preferably 11.5 or less. That is, from the viewpoint of further improving the performance balance of high refractive index, high light transmittance, high heat resistance, coloration resistance, and bleed-out resistance, the base dissociation constant pKb of the stabilizer in the lens resin composition of the first embodiment of the present invention is 6.0 or greater, preferably 6.0 or greater and 15.0 or less, more preferably 7.0 or greater and 14.0 or less, even more preferably 8.0 or greater and 13.0 or less, even more preferably 9.0 or greater and 12.0 or less, and still more preferably 10.0 or greater and 11.5 or less.

[0021] The stabilizer in the lens resin composition of the first embodiment of the present invention preferably includes a stabilizer containing one or more partial structures selected from the group consisting of a partial structure represented by the following general formula (6) and a partial structure represented by the following general formula (7), and more preferably includes a stabilizer containing a partial structure represented by the following general formula (6):

[0022]

[0023] In general formula (6), R ａ represents an alkyl group having 1 to 18 carbon atoms or an aryl group having 6 to 14 carbon atoms.

[0024]

[0025] In the general formula (7), O. represents an oxyl group.

[0026] The lens resin composition of the second embodiment of the present invention comprises a cationic photopolymerization initiator (X) containing a salt formed from an anion represented by the following general formula (1) and a cation, an epoxy compound (Y) containing two or more epoxy groups in the molecule, and a stabilizer containing one or more partial structures selected from the group consisting of a partial structure represented by the following general formula (6) and a partial structure represented by the following general formula (7), and preferably comprises a cationic photopolymerization initiator (X) containing a salt formed from an anion represented by the following general formula (1) and a cation, an epoxy compound (Y) containing two or more epoxy groups in the molecule, and a stabilizer containing a partial structure represented by the following general formula (6):

[0027]

[0028] 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.

[0029]

[0030] In general formula (6), R ａ represents an alkyl group having 1 to 18 carbon atoms or an aryl group having 6 to 14 carbon atoms.

[0031]

[0032] In the general formula (7), O. represents an oxyl group.

[0033] The lens resin composition of the second embodiment of the present invention can form a cured product with an improved balance of performance, including a high refractive index, high light transmittance, high heat resistance, and bleed-out resistance. Suppressing the occurrence of bleed-out during UV curing and heating can also suppress the generation of foreign matter. While the detailed mechanism is unclear, it is presumed that photocationic polymerization initiators containing anionic gallium generate almost no strong acid components even when heated, thereby suppressing heat-induced deterioration such as coloration and the generation of foreign matter. Furthermore, photocationic polymerization initiators containing anionic gallium can suppress adverse effects on various performance characteristics, such as high refractive index, high light transmittance, and high heat resistance, while exhibiting polymerization performance at the level of the prior art. Furthermore, a stabilizer containing one or more partial structures selected from the group consisting of a partial structure represented by general formula (6) and a partial structure represented by general formula (7), when used in combination with a photocationic polymerization initiator containing anionic gallium that generates almost no strong acid components even when heated, can prevent bonding with strong acid components and suppress bleed-out due to changes in compatibility.

[0034] Hereinafter, each component contained in the resin composition for a lens according to the first embodiment of the present invention and the second embodiment of the present invention (hereinafter collectively referred to as the present embodiment) will be described in detail.

[0035] <Cationic Photopolymerization Initiator (X)> The lens resin composition of this embodiment contains a cationic photopolymerization initiator (X) containing a salt formed from an anion represented by the following general formula (1) and a cation.

[0036]

[0037] 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.

[0038] R in general formula (1) １ ~R ４The alkyl group having 1 to 18 carbon atoms represented by is not limited to being linear, branched, or cyclic. Specific examples thereof 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; and the like.

[0039] 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.

[0040] 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.

[0041] 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.

[0042] Examples of the halogen atom include a fluorine atom, a chlorine atom, and a bromine atom.

[0043] 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.

[0044] R １ ~R ４ Examples of the halogen-containing group 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 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.

[0045] 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; ether groups; 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; and a furyl group.

[0046] 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; a dithioester group; 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; a thioacyl group; a thioether group; a thiocyanate ester group; an isothiocyanate ester group; 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; a thiocarboxyl group; a dithiocarboxyl group; a sulfo group; a sulfonyl group; a sulfinyl group; a sulfenyl group; and the like.

[0047] Examples of the nitrogen-containing group 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.

[0048] 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 R are aryl groups having 6 to 14 carbon atoms. １ ~R ４ It is more preferable that all of R are aryl groups having 6 to 8 carbon atoms. １ ~R ４ It is more preferable that all of the groups are aryl groups having 6 carbon atoms.

[0049] R １ ~R４ preferably has a halogen atom as a substituent, and more preferably has a fluorine atom as a substituent. Specifically, the cationic photopolymerization initiator (X) preferably contains, as an anion, at least one anion selected from the anion represented by the following formula (3) and the anion represented by the following formula (4). This makes it possible to further improve the heat resistance of a cured lens body formed from the lens resin composition.

[0050]

[0051]

[0052] The cationic photopolymerization initiator (X) contains a cation that forms a salt with the anion represented by general formula (1).

[0053] 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.

[0054] Examples of oxonium ions include oxoniums such as trimethyloxonium, diethylmethyloxonium, triethyloxonium, and tetramethylenemethyloxonium; pyriliniums such as 4-methylpyrilinium, 2,4,6-trimethylpyrilinium, 2,6-di-tert-butylpyrilinium, and 2,6-diphenylpyrilinium; chromeniums such as 2,4-dimethylchromenium and 1,3-dimethylisochromenium; isochromenium; and the like.

[0055] 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; acridiums such as benzylacridium and phenacylacridium; and the like.

[0056] 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.

[0057] Examples of 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)phenylbis(4-fluorophenyl)sulfonium, 4-(4-benzoylphenylthio)phenyldiphenylsulfonium, 7-isopropyl-9-oxo-10-thia-9,10-dihydroanthracen-2-yldi-p-tolyls ...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)phenylthio]phenyldiphenylsulfonium triarylsulfonium such as 4-[4-(benzoylphenylthio)]phenyldi-p-tolylsulfonium, 4-[4-(benzoylphenylthio)]phenyldiphenylsulfonium, 5-(4-methoxyphenyl)thioanthreneium, 5-phenylthioanthreneium, 5-tolylthioanthreneium, 5-(4-ethoxyphenyl)thioanthrenenium and 5-(2,4,6-trimethylphenyl)thioanthrenenium; diphenylphenacylsulfonium, diphenyl 4-nitrophenacylsulfonium, diphenylbenzylsulfonium and diphenylmethylsulfonium; 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, phenacyltetrahydrothiophenium, dimethylbenzylsulfonium, benzyltetrahydrothiophenium, and octadecylmethylphenacylsulfonium; and the like.

[0058] 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.

[0059] The cationic photopolymerization initiator (X) preferably contains, as a cation, at least one selected from an ammonium ion, a phosphonium ion, a sulfonium ion, and an iodonium ion, more preferably at least one selected from a sulfonium ion and an iodonium ion, still more preferably a sulfonium ion, and still more preferably a triarylsulfonium ion.

[0060] The cationic photopolymerization initiator (X) preferably contains a salt composed of a sulfonium ion and at least one anion selected from the group consisting of an anion represented by the following formula (3) and an anion represented by the following formula (4), thereby further improving the heat resistance of a cured lens body formed from the lens resin composition.

[0061]

[0062]

[0063] 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.

[0064]

[0065] The photocationic polymerization initiator (X) can be synthesized in accordance with a known method described in, for example, WO 2018 / 020974, etc. Alternatively, commercially available CPI-310FG (trade name, photocationic polymerization initiator, manufactured by San-Apro Co., Ltd.) or the like may be procured and used.

[0066] The lower limit of the content of the cationic photopolymerization initiator (X) in the lens resin composition of this embodiment is preferably 0.05 parts by mass or more, more preferably 0.07 parts by mass or more, even more preferably 0.1 parts by mass or more, even more preferably 0.5 parts by mass or more, even more preferably 1.0 parts by mass or more, and even more preferably 1.5 parts by mass or more, relative to 100 parts by mass of the epoxy compound (Y). This improves the balance between high refractive index and high heat resistance. Furthermore, the upper limit of the content of the cationic photopolymerization initiator (X) in the lens resin composition of this embodiment is preferably 15 parts by mass or less, more preferably 10 parts by mass or less, even more preferably 8 parts by mass or less, and even more preferably 6 parts by mass or less, relative to 100 parts by mass of the epoxy compound (Y). This improves the balance between high light transmittance and bleed-out resistance. The cationic photopolymerization initiator (X) may be used alone or in combination. When a mixture of multiple types is used, the total content of the cationic photopolymerization initiator (X) is the sum of the contents of the individual photocationic photopolymerization initiators (X).

[0067] When the cationic photopolymerization initiator (X) has a high molar absorption coefficient at wavelengths of 300 to 380 nm, the content may be adjusted to an appropriate amount depending on the volume and thickness of the lens resin composition when used.

[0068] <Epoxy Compound (Y)> The lens resin composition of this embodiment contains an epoxy compound (Y) containing two or more epoxy groups in the molecule.

[0069] 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.

[0070] 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.

[0071] 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 an aromatic ring, 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.

[0072] 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.).

[0073] 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.

[0074] The epoxy compound (Y) is preferably represented by the following general formula (2).

[0075]

[0076] In 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, and n is the average repeat number and is a real number ranging from 0 to 30.

[0077] 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 alkyl groups having 1 to 18 carbon atoms represented by the formula (I), those having 1 to 4 carbon atoms can be exemplified.

[0078] 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.

[0079] n is preferably 1 to 20, and more preferably 5 to 15. Note that n is calculated from the weight average molecular weight calculated in terms of polystyrene based on the measurement results of GPC (gel permeation chromatography).

[0080] 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.

[0081] When the total non-volatile components of the lens resin composition of this embodiment are taken as 100% by mass, the lower limit of the content of the epoxy compound (Y) is preferably 40% by mass or more, more preferably 45% by mass or more, and even more preferably 50% by mass or more. This improves the balance between high light transmittance and bleed-out resistance. When the total non-volatile components of the lens resin composition of this embodiment are taken as 100% by mass, the upper limit of the content of the epoxy compound (Y) is preferably 99% by mass or less, more preferably 90% by mass or less, even more preferably 80% by mass or less, even more preferably 70% by mass or less, and even more preferably 60% by mass or less. This improves the balance between high refractive index and high heat resistance. The epoxy compound (Y) may be used alone or in combination. When a mixture of multiple types is used, the total content of each epoxy compound (Y) is taken as the content of the epoxy compound (Y).

[0082] <Stabilizer> The resin composition for a lens of the present embodiment contains a stabilizer containing one or more partial structures selected from the group consisting of a partial structure represented by the following general formula (6) and a partial structure represented by the following general formula (7):

[0083]

[0084] In general formula (6), R ａ represents an alkyl group having 1 to 18 carbon atoms or an aryl group having 6 to 14 carbon atoms.

[0085]

[0086] In the general formula (7), O. represents an oxyl group.

[0087] R in general formula (6) ａThe alkyl group having 1 to 18 carbon atoms represented by is not limited to being linear, branched, or cyclic. Specific examples thereof 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; and the like.

[0088] R in general formula (6) ａ 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.

[0089] R in general formula (6) ａ 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.

[0090] R in general formula (6) ａ 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.

[0091] Examples of the halogen atom include a fluorine atom, a chlorine atom, and a bromine atom.

[0092] 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.

[0093] R ａ Examples of the halogen-containing group 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 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.

[0094] 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; ether groups; 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; and a furyl group.

[0095] 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; a dithioester group; 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; a thioacyl group; a thioether group; a thiocyanate ester group; an isothiocyanate ester group; 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; a thiocarboxyl group; a dithiocarboxyl group; a sulfo group; a sulfonyl group; a sulfinyl group; a sulfenyl group; and the like.

[0096] Examples of the nitrogen-containing group 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.

[0097] The stabilizer containing the partial structure represented by general formula (6) is R ａ Preferably, the resin composition contains a compound having 1 to 15 carbon atoms, more preferably 6 to 12 carbon atoms, even more preferably 8 to 12 carbon atoms, and even more preferably 11 carbon atoms. This makes it possible to further improve the balance of performance between a high refractive index, a high light transmittance, a high heat resistance, and bleed-out resistance of a cured product for a lens using the resin composition of this embodiment.

[0098] Examples of stabilizers containing one or more partial structures selected from the group consisting of the partial structure represented by general formula (6) and the partial structure represented by general formula (7) include hindered amine antioxidants such as bis[2,2,6,6-tetramethyl-1-(undecyloxy)piperidin-4-yl] carbonate, bis[1-(octyloxy)-2,2,6,6-tetramethyl-4-piperidinyl] sebacate, 2-[[4,6-bis[butyl[1-(cyclohexyloxy)-2,2,6,6-tetramethylpiperidin-4-yl]amino]-1,3,5-triazin-2-yl]amino]ethanol, and bis(2,2,6,6-tetramethyl-4-piperidyl-1-oxyl) sebacate. Examples of commercially available stabilizers include LA-81 from the Adeka Stab series manufactured by ADEKA Corporation, and Tinuvin 123 and Tinuvin 152 manufactured by BASF Corporation.

[0099] The lower limit of the stabilizer content of this embodiment, i.e., the lower limit of the stabilizer content containing one or more partial structures selected from the group consisting of the partial structure represented by general formula (6) and the partial structure represented by general formula (7), is preferably 0.01 parts by mass or more, more preferably 0.05 parts by mass or more, even more preferably 0.10 parts by mass or more, and even more preferably 0.15 parts by mass or more, relative to 100 parts by mass of the epoxy compound (Y). This allows the lens cured product using the resin composition of this embodiment to have a further improved performance balance between high light transmittance and bleed-out resistance. Furthermore, the upper limit of the stabilizer content of this embodiment, i.e., the upper limit of the stabilizer content containing one or more partial structures selected from the group consisting of the partial structure represented by general formula (6) and the partial structure represented by general formula (7), relative to 100 parts by mass of the epoxy compound (Y), is preferably 5.0 parts by mass or less, more preferably 3.0 parts by mass or less, even more preferably 1.0 part by mass or less, even more preferably 0.5 parts by mass or less, even more preferably 0.3 parts by mass or less, and even more preferably 0.2 parts by mass or less. This makes it possible to further improve the performance balance between high refractive index and high heat resistance of a cured product for a lens using the resin composition of this embodiment. That is, from the viewpoint of further improving the performance balance between high refractive index, high heat resistance, high light transmittance, and bleed-out resistance of a cured product for a lens using the resin composition of this embodiment, the content of the stabilizer of this embodiment is preferably 0.01 parts by mass or more and 5.0 parts by mass or less, more preferably 0.01 parts by mass or more and 3.0 parts by mass or less, even more preferably 0.01 parts by mass or more and 1.0 parts by mass or less, still more preferably 0.05 parts by mass or more and 0.5 parts by mass or less, even more preferably 0.10 parts by mass or more and 0.3 parts by mass or less, and still more preferably 0.15 parts by mass or more and 0.2 parts by mass or less, relative to 100 parts by mass of the epoxy compound (Y).

[0100] The lens resin composition of this embodiment may further contain, in addition to the stabilizer, an antioxidant different from the stabilizer.

[0101] Examples of antioxidants other than the stabilizers include phenol-based antioxidants, phosphorus-based antioxidants, thioether-based antioxidants, and hindered amine-based antioxidants.

[0102] The antioxidant different from the stabilizer preferably includes a phenolic antioxidant, more preferably a hindered phenolic antioxidant.

[0103] 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-based antioxidants include AO-20, AO-30, AO-40, AO-50, AO-60, and AO-80 from the Adeka STAB series manufactured by ADEKA Corporation.

[0104] Examples of phosphorus-based antioxidants include phosphines such as trialkylphosphine and triarylphosphine, trialkyl phosphites, triaryl phosphites, etc. 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 of the Adeka STAB series manufactured by ADEKA Corporation.

[0105] Examples of commercially available thioether antioxidants include AO-26, AO-412S, and AO-503A of the Adeka STAB series manufactured by ADEKA Corporation.

[0106] Examples of the hindered amine antioxidant include 2,4-bis[N-butyl-N-(1-cyclohexyloxy-2,2,6,6-tetramethylpiperidin-4-yl)amino]-6-(2-hydroxyethylamine)-1,3,5-triazine and decanedioic acid bis(2,2,6,6-tetramethyl-1-(octyloxy)-4-piperidinyl)ester. Examples of commercially available hindered amine antioxidants include 111FDL, 123, 144, 152, 292, and 5100 from the TINUVIN series manufactured by BASF.

[0107] When the lens resin composition of this embodiment further contains an antioxidant different from the stabilizer, the content thereof may be appropriately set depending on the purpose. From the viewpoint of obtaining a cured product with little coloration, the lower limit of the content of the antioxidant different from the stabilizer in the lens resin composition of this embodiment is preferably 0.01 parts by mass or more, more preferably 0.1 parts by mass or more, even more preferably 0.3 parts by mass or more, even more preferably 0.5 parts by mass or more, and even more preferably 0.8 parts by mass or more, relative to 100 parts by mass of the epoxy compound (Y). Furthermore, from the viewpoint of obtaining a resin composition with excellent curability, the upper limit of the content of the antioxidant different from the stabilizer is preferably 5.0 parts by mass or less, more preferably 3.0 parts by mass or less, and even more preferably 1.0 part by mass or less.

[0108] <Other Components> The lens resin composition of the present 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.

[0109] (Monofunctional Epoxy Compound (Z)) The lens resin composition of this embodiment preferably further contains a monofunctional epoxy compound (Z) represented by general formula (5). This can further improve the heat resistance of a lens cured product formed from the lens resin composition. This can also improve the glass adhesion of the lens resin composition.

[0110]

[0111] In the general formula (5), A is selected from a single bond, an oxygen atom, and a sulfur atom; １０ is alkylene having 1 to 8 carbon atoms, and any methylene group may be substituted with an oxygen atom.

[0112] A is preferably a single bond. １０ is preferably alkylene having 1 to 4 carbon atoms, and more preferably alkylene having 1 or 2 carbon atoms.

[0113] R １０ It is preferred that any methylene group is substituted with an oxygen atom.

[0114] The monofunctional epoxy compound (Z) preferably contains o-phenylphenol glycidyl ether.

[0115] 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.).

[0116] When the lens resin composition of this embodiment contains a monofunctional epoxy compound (Z), the lower limit of the content of the monofunctional epoxy compound (Z) in the lens resin composition of this embodiment is preferably 1% by mass or more, more preferably 5% by mass or more, even more preferably 10% by mass or more, even more preferably 20% by mass or more, even more preferably 30% by mass or more, and even more preferably 35% by mass or more, based on the non-volatile components of the lens resin composition of this embodiment. This further improves the heat resistance of a cured lens product formed from the lens resin composition. Furthermore, when the lens resin composition of this embodiment contains a monofunctional epoxy compound (Z), the upper limit of the content is preferably 70% by mass or less, more preferably 60% by mass or less, even more preferably 50% by mass or less, and even more preferably 40% by mass or less, based on the non-volatile components of the lens resin composition of this embodiment. This further improves the glass adhesion of the lens resin composition.

[0117] When the lens resin composition of this embodiment contains a monofunctional epoxy compound (Z), the lower limit of the content of the monofunctional epoxy compound (Z) in the lens resin composition of this embodiment is preferably 1 part by mass or more, more preferably 5 parts by mass or more, even more preferably 10 parts by mass or more, even more preferably 20 parts by mass or more, even more preferably 30 parts by mass or more, even more preferably 40 parts by mass or more, even more preferably 50 parts by mass or more, even more preferably 60 parts by mass or more, and even more preferably 65 parts by mass or more, relative to 100 parts by mass of the epoxy compound (Y). This can further improve the heat resistance of a cured lens product formed from the lens resin composition. Furthermore, when the lens resin composition of this embodiment contains a monofunctional epoxy compound (Z), the upper limit of the content is preferably 200 parts by mass or less, more preferably 150 parts by mass or less, even more preferably 100 parts by mass or less, even more preferably 80 parts by mass or less, and even more preferably 75 parts by mass or less, relative to 100 parts by mass of the epoxy compound (Y). This can further improve the glass adhesion of the lens resin composition.

[0118] 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).

[0119] (Oxetane Compound (W)) The lens resin composition of 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. This can also improve the glass adhesion of the lens resin composition. This can also improve the curability of the resin composition.

[0120] The oxetane compound (W) is not particularly limited, and generally known compounds can be used. Specific examples of the oxetane compound (W) include oxetane, 2-methyloxetane, 3-methyloxetane, 2,2-dimethyloxetane, 3,3-dimethyloxetane, 3-ethyl-3-hydroxymethyloxetane, and biphenyl-type oxetane.

[0121] 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).

[0122] The oxetane compound (W) preferably includes a biphenyl-type oxetane compound. Specific examples of the biphenyl-type oxetane include xylylene bisoxetane.

[0123] Examples of commercially available oxetane compounds (W) include Aronoxetane OXT-101 (3-ethyl-3-hydroxymethyloxetane, manufactured by Toagosei Co., Ltd.) and Aronoxetane OXT-121 (xylylenebisoxetane, manufactured by Toagosei Co., Ltd.).

[0124] When the lens resin composition of this embodiment contains an oxetane compound (W), the lower limit of the content of the oxetane compound (W) in the lens resin composition of this embodiment is preferably 0.01% by mass or more, more preferably 0.1% by mass or more, even more preferably 1% by mass or more, even more preferably 2% by mass or more, even more preferably 3% by mass or more, and even more preferably 4% by mass or more, based on the non-volatile components of the lens resin composition of this embodiment. This can further improve the heat resistance of a cured lens product formed from the lens resin composition and the curability of the lens resin composition. Furthermore, when the lens resin composition of this embodiment contains an oxetane compound (W), the upper limit of the content of the oxetane compound (W) in the lens resin composition of this embodiment 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, even more preferably 10% by mass or less, and even more preferably 5% by mass or less. This can further improve the glass adhesion of the lens resin composition.

[0125] When the lens resin composition of this embodiment contains an oxetane compound (W), the lower limit of the content of the oxetane compound (W) in the lens resin composition of this embodiment is preferably 1 part by mass or more, more preferably 5 parts by mass or more, and even more preferably 9 parts by mass or more, per 100 parts by mass of the epoxy compound (Y). This makes it possible to further improve the heat resistance of a cured lens product formed from the lens resin composition and the curability of the lens resin composition. Furthermore, when the lens resin composition of this embodiment contains an oxetane compound (W), the upper limit of the content of the oxetane compound (W) in the lens resin composition of this embodiment is preferably 200 parts by mass or less, more preferably 150 parts by mass or less, even more preferably 100 parts by mass or less, still more preferably 80 parts by mass or less, still more preferably 60 parts by mass or less, still more preferably 40 parts by mass or less, still more preferably 25 parts by mass or less, still more preferably 15 parts by mass or less, and even more preferably 10 parts by mass or less. This makes it possible to further improve the glass adhesion of the lens resin composition.

[0126] (Solvent) The solvent contained in the lens resin composition of this embodiment is not particularly limited, but one that can dissolve 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.

[0127] When the resin composition for a lens of this embodiment contains a solvent, 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, for example, 95% by mass or less, preferably 10 to 90% by mass, when the total of all components of the resin composition for a lens of this embodiment is taken as 100% by mass. A single solvent may be used, or multiple solvents may be used in combination, and when multiple solvents are used in combination, the total solvent content is the sum of the contents of the individual solvents.

[0128] When the epoxy compound (Y) is liquid at room temperature (25° C.), coating and the like can be suitably carried out even when no solvent is blended or substantially no solvent is blended.

[0129] (Adhesion Imparting Agent) The adhesion imparting agent contained in the resin composition for a lens of the present 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.

[0130] 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.

[0131] When the lens resin composition of this embodiment contains an adhesion-imparting agent, the content of the adhesion-imparting agent in the lens resin composition of this embodiment 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, even more preferably 2% by mass or less, and even more preferably 1% by mass or less, of the non-volatile components of the lens resin composition of this embodiment. When the lens resin composition of this embodiment contains an adhesion-imparting agent, the content of the adhesion-imparting agent in the lens resin composition of this embodiment 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 lens resin composition of this embodiment. A single adhesion-imparting agent may be used, or multiple adhesion-imparting agents may be used in combination. When multiple adhesion-imparting agents are used in combination, the total content of the adhesion-imparting agent is the sum of the contents of the individual adhesion-imparting agents.

[0132] (Polyol Compound) When the lens resin composition of this embodiment contains a polyol compound, the polyol compound 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.

[0133] When the lens resin composition of this embodiment contains a polyol compound, the content of the polyol compound in the lens resin composition of this embodiment is not particularly limited as long as it is within a range that does not impair the effects of the present invention, and is, for example, 1 to 30 parts by mass, preferably 2 to 25 parts by mass, relative to 100 parts by mass of the epoxy compound (Y). One type of polyol compound may be used alone, or multiple types may be used in combination. When multiple types are used in combination, the total content of the individual polyol compounds is defined as the content of the polyol compound.

[0134] The polyol compound contained in the lens resin composition of this embodiment is a compound that can cure the epoxy compound to a high crosslink density by heating. For example, the polyhydric phenol compounds listed in Japanese Patent Publication No. 5967824 can be used.

[0135] (Polyphenol Compound) When the lens resin composition of this embodiment contains a polyphenol compound, the content of the polyphenol compound in the lens resin composition of this embodiment is not particularly limited as long as it is within a range that does not impair the effects of the present invention, and is, for example, 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). A single polyphenol compound may be used, or multiple types may be used in combination. When multiple types are used in combination, the total content of the respective polyphenol compounds is defined as the content of the polyphenol compound.

[0136] (Sensitizer) The sensitizer contained in the lens resin composition of this embodiment plays a role in donating absorbed light energy to the photocationic polymerization initiator. Examples of the sensitizer include thioxanthones and anthracene compounds having alkoxy groups at the 9- and 10-positions (9,10-dialkoxyanthracene derivatives).

[0137] When the lens resin composition of this embodiment contains a sensitizer, the content of the sensitizer in the lens resin composition of this embodiment 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 this embodiment contains a sensitizer, the content of the sensitizer in the lens resin composition of this embodiment is not particularly limited as long as it is within a range that does not impair the effects of the present invention, and is, for example, 0.1 parts by mass or more, relative to 100 parts by mass of the cationic photopolymerization initiator (X). A single sensitizer may be used, or multiple sensitizers may be used in combination. When multiple sensitizers are used in combination, the total content of the sensitizers is the sum of the contents of the individual sensitizers.

[0138] (Ion Catcher) The ion catcher contained in the lens resin composition of 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 a weak acid when irradiated with ultraviolet light can be used as the ion catcher.

[0139] When the resin composition for a lens of this embodiment contains an ion catcher, the content of the ion catcher in the resin composition for a lens of this embodiment is not particularly limited as long as it is within a range that 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 cationic photopolymerization initiator (X). In the case of an onium weak acid salt compound, the content is preferably 0.001 to 2 parts by mass relative to 100 parts by mass of the cationic photopolymerization initiator (X). A single 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.

[0140] (Other cationic photopolymerization initiators) The lens resin composition of this embodiment may contain a cationic photopolymerization initiator (other cationic photopolymerization initiator) other than the cationic photopolymerization initiator (X). The other cationic photopolymerization initiator contained in the lens resin composition of this embodiment is not particularly limited, and known ones can be used.

[0141] Other examples of the cationic photopolymerization initiator 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), BF ４ － [(Rf) n PF ６－ｎ ] － (Rf: an alkyl group in which 80% or more of the hydrogen atoms are substituted with fluorine atoms, n: an integer of 0 to 5), AsF ６ － , SbF ６ － Examples of suitable anions include those having pentafluorohydroxyantimonate or the like as an anion.

[0142] The content of the other cationic photopolymerization initiator in the lens resin composition of the present embodiment 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).

[0143] The other cationic photopolymerization initiators may be used singly or in combination. When a mixture of multiple types is used, the total content of the other cationic photopolymerization initiators is defined as the content of the other cationic photopolymerization initiators.

[0144] (Other Additives) In addition to the components described above, the resin composition for a lens of this embodiment may contain various additives such as a thermoplastic resin, a colorant, a thickener, an antifoaming agent, and a leveling agent, as needed.

[0145] <Production Method> The lens resin composition of this embodiment can be obtained by stirring and mixing the above-mentioned components by a conventional method. Alternatively, dispersion and mixing may be carried out using a dispersing machine such as a dissolver, homogenizer, or triple roll mill, as necessary. After mixing, the components may be further filtered using a mesh, membrane filter, or the like.

[0146] <Physical Properties> The viscosity of the lens resin composition of this embodiment can be measured, for example, using an E-type viscometer. When the lens resin composition of this embodiment is measured using an E-type viscometer at a temperature of 25°C and a rotation speed of 2.5 rpm, the lower limit of the viscosity is preferably 100 mPa·s or more, more preferably 200 mPa·s or more, even more preferably 500 mPa·s or more, and even more preferably 700 mPa·s or more. This improves the curability of the lens resin composition. Furthermore, the upper limit of the viscosity is preferably 5000 mPa·s or less, more preferably 3000 mPa·s or less, even more preferably 2000 mPa·s or less, and even more preferably 1500 mPa·s or less. This improves the moldability of the lens resin composition.

[0147] The lens resin composition of this embodiment is prepared by applying the lens resin composition to a glass plate in a thickness of 250 μm, and then irradiating the lens with a wavelength of 365 nm, an irradiation intensity of 500 mW / cm, and an accumulated irradiation amount of 6000 mJ / cm. ２ and then heated in a nitrogen atmosphere at 120°C for 30 minutes, the refractive index of the cured product for a lens obtained is preferably 1.55 or more, more preferably 1.56 or more, even more preferably 1.57 or more, even more preferably 1.58 or more, and even more preferably 1.59 or more. When the refractive index of the cured product for a lens is equal to or greater than the above-mentioned lower limit, the optical properties of the lens can be improved. Furthermore, the upper limit of the refractive index of the cured product for a lens is not particularly limited, but is, for example, 1.90 or less, 1.80 or less, 1.75 or less, or 1.70 or less.

[0148] The refractive index of the lens cured product can be measured with an Abbe refractometer.

[0149] The lens resin composition of this embodiment is prepared by applying the lens resin composition to a glass plate in a thickness of 250 μm, and then irradiating the lens with a wavelength of 365 nm, an irradiation intensity of 500 mW / cm, and an accumulated irradiation amount of 6000 mJ / cm. ２ The cured product for a lens obtained by UV exposure under the conditions of (a) and (b) and heating under a nitrogen atmosphere at 120°C for 30 minutes has a lower limit of light transmittance in the thickness direction, as measured using an ultraviolet-visible-near-infrared spectrophotometer under the following (measurement conditions), of preferably 70% or more, more preferably 75% or more, even more preferably 80% or more, and even more preferably 82% or more. This makes it possible to produce lenses with higher transparency. The upper limit of the light transmittance is not particularly limited, but is, for example, 100% or less.

[0150] (Measurement conditions) Measurement method: Transmission method Measurement wavelength: 400 nm Reference: Air Detector: Integrating sphere / photomultiplier tube (200 nm to 850 nm) Integrating sphere: PbS (850 nm to 2600 nm)

[0151] The lens resin composition of this embodiment is prepared by applying the lens resin composition to a glass plate in a thickness of 250 μm, and then irradiating the lens with a wavelength of 365 nm, an irradiation intensity of 500 mW / cm, and an accumulated irradiation amount of 6000 mJ / cm. ２ The lens cured product obtained by UV exposure under the conditions of (a) and (b) and heating under a nitrogen atmosphere at 120°C for 30 minutes is subjected to a heat resistance test by heating for 168 hours in an oven set at 125°C under an air atmosphere, and then the lower limit of the light transmittance (after the heat resistance test) in the thickness direction measured using an ultraviolet-visible-near-infrared spectrophotometer under the following (measurement conditions) is preferably 70% or more, more preferably 72% or more, even more preferably 74% or more, even more preferably 76% or more, even more preferably 78% or more, and even more preferably 79% or more. This enables the production of lenses with higher transparency. The upper limit of the light transmittance (after the heat resistance test) is not particularly limited, but is, for example, 100% or less.

[0152] (Measurement conditions) Measurement method: Transmission method Measurement wavelength: 400 nm Reference: Air Detector: Integrating sphere / photomultiplier tube (200 nm to 850 nm) Integrating sphere: PbS (850 nm to 2600 nm)

[0153] <Use> The resin composition for lenses of the present embodiment is suitably used for wafer-level lenses.

[0154] A wafer-level lens is a lens manufactured by simultaneously creating a number of lenses on a wafer-shaped resin (wafer-level lens array) and then cutting it up. 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 with respect to the substrate 2. The lenses 10 formed on the wafer-level lens array 1 are then cut up individually.

[0155] Therefore, wafer-level lenses have the advantage of being able to produce several hundred lenses at a time, resulting in excellent production efficiency.

[0156] Another advantage of wafer-level lenses is that they can be used to create thin, compact lenses, which are difficult to achieve with injection molding. 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 these sizes, wafer-level lenses are suitable for use in cameras in electronic devices such as smartphones, tablet devices, and laptop computers.

[0157] The resin composition for lenses of the present embodiment can form a cured product for lenses having an improved balance of performance, including high refractive index, high light transmittance, high heat resistance, and bleed-out resistance, and is therefore suitable for use in wafer-level lenses, which require thinness and small size.

[0158] [Cured product for lens] The cured product for lens of this embodiment can be obtained by curing the above-mentioned resin composition for lens. Furthermore, the cured product for lens of this embodiment may be subjected to reflow treatment in a temperature environment of 30°C or higher and 300°C or lower in order to mount a component such as a wafer-level lens comprising the cured product for lens of this embodiment on a circuit board.

[0159] The glass transition temperature (Tg) of the cured product for a lens of this embodiment, measured by the following (method), is preferably 70°C or higher and 200°C or lower, more preferably 70°C or higher and 180°C or lower, even more preferably 80°C or higher and 160°C or lower, even more preferably 90°C or higher and 140°C or lower, and even more preferably 100°C or higher and 120°C or lower.

[0160] (Method) A resin composition for a lens was dropped onto a PDMS substrate (120 × 80 × 1 mmt), and the substrate was sandwiched between two PDMS substrates similar to those described above via a 250 μm-thick silicone spacer and fixed with clips. A metal halide lamp was used to irradiate the lens with a UVA irradiation intensity of 500 mW / cm and an accumulated irradiation dose of 6000 mJ / cm. ２ The lens resin composition is then exposed to UV light so that the lens resin composition becomes 120°C, and cured. The cured lens resin composition is then released from the PDMS substrate and heated in a nitrogen atmosphere at 120°C for 30 minutes to obtain a cured lens product before reflow treatment. The cured lens product before reflow treatment is then subjected to a reflow heating treatment under the conditions shown in Table 1 below to obtain a cured lens product after reflow treatment. The solid viscoelasticity of the cured lens product after reflow treatment is then measured under the following conditions. Apparatus: RSA-G2 (manufactured by TA Instruments) Deformation mode: Tensile Temperature range: -50°C to 180°C Heating temperature: 3°C / min Frequency: 1 Hz Environment: N ２ Then, from the results of the viscoelasticity measurement, the temperature at which the value of tan δ shows a maximum value is measured as Tg.

[0161]

[0162] The refractive index of the cured product for a lens of this embodiment is preferably 1.55 or more, more preferably 1.56 or more, even more preferably 1.57 or more, even 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 a cured product for a lens. The upper limit of the refractive index of the cured product for a lens is not particularly limited, but is, for example, 1.90 or less, 1.80 or less, 1.75 or less, or 1.70 or less.

[0163] The lower limit of the light transmittance in the thickness direction of the cured product for a lens of this embodiment (before heat resistance testing) is preferably 70% or more, more preferably 75% or more, even more preferably 80% or more, and even more preferably 82% or more. The light transmittance can be determined by the procedure described above as the procedure for measuring the light transmittance of a cured product for a lens. The upper limit of the light transmittance is not particularly limited, but is, for example, 100% or less.

[0164] The cured product for lenses of this embodiment has an improved balance of performance, including high refractive index, high light transmittance, high heat resistance, and bleed-out resistance, and is therefore suitable for use in wafer-level lenses, which are required to be thin and small.

[0165] [Lens] The lens of the present embodiment comprises the above-described cured product for a lens.

[0166] The lens of 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.

[0167] 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

[0168] The lens resin composition (lens cured product) 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. Resins may also be used. Resins are easy to process and are suitable for easily and inexpensively forming lenses.

[0169] 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.

[0170] The lens of this embodiment has an improved balance of performance including a high refractive index, high light transmittance, high heat resistance, and bleed-out resistance, and is therefore suitable for use as a wafer-level lens for which thinness and small size are required.

[0171] The diameter of the wafer level lens is, for example, 1 to 10 mm, preferably 1 to 5 mm, and the thickness of the wafer level lens is, for example, 100 to 2000 μm, preferably 100 to 1000 μm.

[0172] Wafer-level lenses are suitable for use in cameras in electronic devices such as smartphones, tablet computers, and laptop computers.

[0173] Although the embodiments of the present invention have been described above, these are merely examples of the present invention, and various other configurations may be adopted. Furthermore, the present invention is not limited to the above-described embodiments, and modifications and improvements within the scope of achieving the object of the present invention are included in the present invention.

[0174] 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.

[0175] <Preparation of Lens Resin Composition> The raw materials listed in Table 3 were stirred and mixed while heating at 50°C until homogenous, to obtain lens resin compositions for each Example and Comparative Example. The raw materials listed in Table 3 are as follows.

[0176] Photocationic polymerization initiator (X): triarylsulfonium-tetrakispentafluorophenyl gallate, manufactured by San-Apro Ltd., product name: CPI-310FG Photocationic polymerization initiator: thiophenyldiphenylsulfonium tris(pentafluoroethyl)trifluorophosphate, manufactured by San-Apro Ltd., product name: CPI-210S

[0177] Epoxy compound (Y): bisphenol A type epoxy resin, manufactured by DIC Corporation, product name: EXA-850CRP, epoxy equivalent: 158 to 168 g / eq

[0178] Monofunctional epoxy compound (Z): o-phenylphenol glycidyl ether, manufactured by Yokkaichi Chemical Co., Ltd., product name: OPP-EP

[0179] Oxetane compound (W): biphenyl-type oxetane compound (xylylene bisoxetane), manufactured by Toagosei Co., Ltd., product name: Aron Oxetane OXT-121

[0180] Adhesion promoter: silane coupling agent (3-glycidoxypropyltrimethoxysilane), manufactured by Shin-Etsu Chemical Co., Ltd., product name: KBM-403

[0181] Antioxidant: phenolic antioxidant (pentaerythritol tetrakis [3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate]), manufactured by ADEKA Corporation, product name: Adekastab AO-60

[0182] Light stabilizer 1: hindered amine light stabilizer (bis[2,2,6,6-tetramethyl-1-(undecyloxy)piperidin-4-yl] carbonate), manufactured by ADEKA Corporation, product name: Adekastab LA-81, base dissociation constant pKb: 11.3 Light stabilizer 2: hindered amine light stabilizer (bis(1,2,2,6,6-pentamethyl-4-piperidyl) sebacate), manufactured by ADEKA Corporation, product name: Adekastab LA-72, base dissociation constant pKb: 5.8 Light stabilizer 3: hindered amine light stabilizer (bis[1-(octyloxy)-2,2,6,6-tetramethyl-4-piperidinyl] sebacate), manufactured by BASF Corporation, product name: Tinuvin 123, base dissociation constant pKb: 11.5 Light stabilizer 4: hindered amine light stabilizer (2-[[4,6-bis[butyl[1-(cyclohexyloxy)-2,2,6,6-tetramethylpiperidin-4-yl]amino]-1,3,5-triazin-2-yl]amino]ethanol), manufactured by BASF Corporation, product name: Tinuvin 152, base dissociation constant pKb: 10.6 Light stabilizer 5: hindered amine light stabilizer (bis(2,2,6,6-tetramethyl-4-piperidyl-1-oxyl) sebacate), manufactured by Tokyo Chemical Industry Co., Ltd., base dissociation constant pKb: 10.1

[0183] <Base Dissociation Constant pKb> The base dissociation constant pKb of each light stabilizer was measured by the following method. 0.1 g of each light stabilizer was dissolved in 100 g of an 80% by mass methanol-containing aqueous solution, and the solution was titrated with a 3N-HCl aqueous solution while measuring the pH using a pH meter (manufactured by Horiba, Ltd.) to obtain a pH titration curve. The pKb value was calculated by a graphical method using the obtained pH titration curve.

[0184] <Viscosity> The viscosity of the lens resin composition of each Example and Comparative Example 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 appropriately selected from 1°34' x R24, 3° x R14, and 3° x R9.7 depending on the viscosity of the sample. The results are shown in Table 3.

[0185] <Preparation of Lens Cured Material 1> A lens resin composition was dropped onto a PDMS substrate (120 × 80 × 1 mmt, manufactured by DuPont Toray Specialty Materials Co., Ltd.), and the lens resin composition was sandwiched between the same PDMS substrates as above via a 250 μm-thick silicone spacer and fixed with clips. Using a metal halide lamp, UVA irradiation intensity was 500 mW / cm and cumulative irradiation amount was 6000 mJ / cm. ２ The lens resin composition was then cured by UV exposure until the temperature reached 120°C. The cured lens resin composition was then released from the PDMS substrate and heated at 120°C for 30 minutes in a nitrogen atmosphere, thereby obtaining a lens cured material 1 before reflow treatment.

[0186] <Reflow Treatment> The lens cured material 1 before the reflow treatment in each of the examples and comparative examples was subjected to a reflow heating treatment using a tabletop heating furnace (SVO-1, manufactured by Synapex Co., Ltd.) under the conditions shown in Table 2 below, to obtain a lens cured material 1 after the reflow treatment.

[0187]

[0188] <Measurement of refractive index> The refractive index of the lens cured material 1 after reflow treatment in each example and comparative example was measured using an Abbe refractometer (DR-M2, manufactured by Atago Co., Ltd.). RE-3520 (589 nm, D line, manufactured by Atago Co., Ltd.) was used as the interference filter, and RE-1196 (monobromonaphthalene, manufactured by Atago Co., Ltd.) was used as the intermediate liquid, and the sample temperature was set to 25°C. The results are shown in Table 3.

[0189] <Measurement of Glass Transition Temperature (Tg)> The solid viscoelasticity of the lens cured material 1 after reflow treatment in each of the Examples and Comparative Examples was measured under the following conditions: Apparatus: RSA-G2 (manufactured by TA Instruments) Deformation mode: Tensile Temperature range: -50°C to 180°C Heating rate: 3°C / min Frequency: 1 Hz Environment: N ２ atmosphere

[0190] From the results of the viscoelasticity measurements, the temperature at which the value of tan δ was at its maximum was measured as Tg.

[0191] <Preparation of Lens Cured Material 2> A lens resin composition was dropped onto a PDMS substrate (120 × 80 × 1 mmt, manufactured by DuPont Toray Specialty Materials Co., Ltd.), and the substrate was sandwiched between borosilicate glass substrates (D263t eco, 120 × 80 × 0.2 mmt, manufactured by SCHOTT) via a 250 μm-thick silicone spacer, and then fixed with clips. Using a metal halide lamp, UVA irradiation intensity was 500 mW / cm and cumulative irradiation amount was 6000 mJ / cm. ２ The lens resin composition was then cured by UV exposure until the temperature reached 120°C. The cured lens resin composition was then released from the PDMS substrate and heated at 120°C for 30 minutes in a nitrogen atmosphere, thereby obtaining a lens cured material 2 before reflow treatment.

[0192] <Reflow Treatment> The lens cured material 2 before the reflow treatment in each of the Examples and Comparative Examples was subjected to a reflow heating treatment using a tabletop heating furnace (SVO-1, manufactured by Synapex Co., Ltd.) under the conditions shown in Table 2 above, to obtain a lens cured material 2 after the reflow treatment.

[0193] <Light transmittance> In each example and comparative example, the light transmittance in the thickness direction of the lens cured product 2 after reflow treatment was measured under the following (measurement conditions) to obtain the light transmittance before the heat resistance test. The measurement was performed by attaching the lens cured product 2 to an integrating sphere, with the glass surface as the light incident surface. The results are shown in Table 3. (Measurement conditions) Measuring device: UH4150 (ultraviolet-visible-near-infrared spectrophotometer, manufactured by Hitachi High-Tech Science Corporation) Measurement method: transmittance method Measurement wavelength: 400 nm Reference: air Detector: integrating sphere / photomultiplier tube (200 nm to 850 nm) Integrating sphere: PbS (850 nm to 2600 nm)

[0194] <Light transmittance after heat resistance test> First, a heat resistance test was carried out by heating the lens cured product 2 after reflow treatment in an air atmosphere in an oven set at 125°C for 168 hours. For the lens cured product 2 after the heat resistance test, the light transmittance in the thickness direction was measured under the above conditions to obtain the light transmittance after the heat resistance test. The results are shown in Table 3.

[0195] <Evaluation of Presence or Absence of Foreign Matter> For each Example and Comparative Example, the resin surface of the lens cured product 2 before and after the reflow treatment and the lens cured product 2 after the heat resistance test obtained in the above <Light transmittance after heat resistance test> was observed at 50x magnification using a 3D measuring laser microscope (LEXT OLS5000, manufactured by Olympus Corporation) for the presence or absence of foreign matter. When this was done, it was determined that foreign matter had occurred if 10 or more convex components with a diameter of 1.0 μm or more and a height of 50 nm or more were confirmed within an observation area of ​​250 μm square. The results are shown in Table 3.

[0196]

[0197] While no foreign matter was observed in any of the Examples, foreign matter was observed in Comparative Example 1. This means that the resin compositions of each Example suppressed the occurrence of bleed-out during UV curing and heating. Furthermore, the refractive index and light transmittance of each Example were at a high level comparable to that of Comparative Example 1. On the other hand, Comparative Examples 2 and 3, which did not contain the specific photocationic polymerization initiator (X), showed a reduced light transmittance after the heat resistance test, indicating inferior heat resistance. From these findings, it can be seen that the lens resin compositions of the Examples had an improved performance balance of high refractive index, high light transmittance, high heat resistance, and bleed-out resistance compared to the lens resin compositions of each Comparative Example.

[0198] This application claims priority based on Japanese Patent Application No. 2023-107856, filed on June 30, 2023, the disclosure of which is incorporated herein in its entirety. The present invention also includes the following aspects: 1. A resin composition for a lens, comprising: a cationic photopolymerization initiator (X) containing a salt formed from an anion represented by the following general formula (1) and a cation; an epoxy compound (Y) containing two or more epoxy groups in the molecule; and a stabilizer containing a partial structure represented by the following general formula (6). (In the 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. (In the general formula (6), R ａrepresents an alkyl group having 1 to 18 carbon atoms or an aryl group having 6 to 14 carbon atoms.) 2. The lens resin composition according to 1., wherein the epoxy compound (Y) is represented by the following general formula (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, and n is the average repeat number and represents a real number in the range of 0 to 30.) 3. The lens resin composition according to 1. or 2., wherein the cationic photopolymerization initiator (X) contains, as an anion, at least one anion selected from the group consisting of an anion represented by the following formula (3) and an anion represented by the following formula (4): 4. The lens resin composition according to any one of 1. to 3., wherein the photocationic polymerization initiator (X) contains a sulfonium ion as a cation. 5. The lens resin composition according to any one of 1. to 4., further comprising a monofunctional epoxy compound (Z) represented by the following general formula (5): (In the general formula (5), A is selected from a single bond, an oxygen atom, and a sulfur atom; R １０is alkylene having 1 to 8 carbon atoms, and any methylene group may be substituted with an oxygen atom.) 6. The lens resin composition according to 5., wherein the monofunctional epoxy compound (Z) comprises o-phenylphenol glycidyl ether. 7. The lens resin composition according to any of 1. to 6., further comprising an oxetane compound (W). 8. The lens resin composition according to 7., wherein the oxetane compound (W) comprises a biphenyl-type oxetane compound. 9. The lens resin composition according to any of 1. to 8., wherein the viscosity of the lens resin composition measured with an E-type viscometer at a temperature of 25°C and a rotation speed of 2.5 rpm is 100 mPa·s or more and 5000 mPa·s or less. 10. 1. to 9. The resin composition for a lens according to any one of claims 1 to 4, wherein the resin composition for a lens is applied to a glass substrate in a thickness of 250 μm, and the applied light is irradiated at a wavelength of 365 nm, an irradiation intensity of 500 mW / cm, and an accumulated irradiation amount of 6000 mJ / cm. ２ 11. A resin composition for a lens according to any one of 1. to 10., wherein the resin composition for a lens is applied to a glass substrate in a thickness of 250 μm, and the applied composition is exposed to UV light at a wavelength of 365 nm, an irradiation intensity of 500 mW / cm, and an accumulated irradiation amount of 6000 mJ / cm. ２ 12. A lens resin composition according to any one of 1. to 11., wherein the lens resin composition is applied to a glass substrate to a thickness of 250 μm, and the cured product is exposed to UV light under the conditions of a wavelength of 365 nm, an irradiation intensity of 500 mW / cm, and an accumulated irradiation amount of 6000 mJ / cm, and the cured product is then heated under the conditions of 120°C for 30 minutes in a nitrogen atmosphere, and the light transmittance in the thickness direction is measured using an ultraviolet-visible-near-infrared spectrophotometer under the following (measurement conditions): (Measurement conditions) Measurement method: Transmission method Measurement wavelength: 400 nm Reference: Air Detector: Integrating sphere / photomultiplier tube (200 nm to 850 nm) Integrating sphere: PbS (850 nm to 2600 nm) 13. A lens resin composition according to any one of 1. to 11., wherein the lens resin composition is applied to a glass substrate to a thickness of 250 μm, and the cured product is then exposed to UV light under the conditions of a wavelength of 365 nm, an irradiation intensity of 500 mW / cm, and an accumulated irradiation amount of 6000 mJ / cm ２A lens resin composition, wherein the cured product obtained by UV exposure under the conditions of (1) above and heating under a nitrogen atmosphere at 120°C for 30 minutes has a light transmittance in the thickness direction of 70% or more, measured using an ultraviolet-visible-near-infrared spectrophotometer under the following (measurement conditions) after the following (heat resistance test). (Measurement conditions) Measurement method: Transmission method Measurement wavelength: 400 nm Reference: Air Detector: Integrating sphere / photomultiplier tube (200 nm to 850 nm) Integrating sphere: PbS (850 nm to 2600 nm) (Heat resistance test) The cured product is heated in an oven set at 125°C under an air atmosphere for 168 hours. 13. The lens resin composition according to any one of (1) to (12), wherein the lens resin composition is used for a wafer-level lens. 14. A lens cured product obtained by curing the lens resin composition according to any one of (1) to (13). 15. A lens comprising the lens cured product according to (14).

[0199] 1 wafer-level lens array 2 substrate 10 lens

Claims

1. A photocationic polymerization initiator (X) comprising an anion represented by the following general formula (1) and a cation, An epoxy compound (Y) containing two or more epoxy groups in its molecule, A stabilizer with a base dissociation constant pKb of 6.0 or higher, as determined by the <Method for measuring base dissociation index pKb> below, A resin composition for lenses containing the following: <Method for measuring the base dissociation index pKb> Dissolve 0.1 g of stabilizer in 100 g of an 80% by mass methanol aqueous solution. Obtain a pH titration curve by titrating this solution with a 3N HCl aqueous solution and measuring the pH using a pH meter. Calculate the pKb value using the obtained pH titration curve by the graphing method.

2. A lens resin composition according to claim 1, A lens resin composition comprising a stabilizer comprising a stabilizer which includes one or more substructures selected from the group consisting of a substructure represented by the following general formula (6) and a substructure represented by the following general formula (7). 【Chemistry 1】 (In the above general formula (1), R １ ~R ４ Each of these 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 above general formula (6), R ａ (This represents an alkyl group having 1 to 18 carbon atoms or an aryl group having 6 to 14 carbon atoms.) 【Transformation 3】 (In the general formula (7) above, O• represents an oxyl group.)

3. A lens resin composition according to claim 1 or 2, A lens resin composition wherein the base dissociation constant pKb of the stabilizer is 12.0 or less.

4. A photocationic polymerization initiator (X) comprising an anion represented by the following general formula (1) and a cation, An epoxy compound (Y) containing two or more epoxy groups in its molecule, A stabilizer comprising one or more substructures selected from the group consisting of the substructure represented by the following general formula (6) and the substructure represented by the following general formula (7), A resin composition for lenses containing the following: 【Chemistry 4】 (In the above general formula (1), R １ ~R ４ Each of these independently represents an alkyl group having 1 to 18 carbon atoms or an aryl group having 6 to 14 carbon atoms. 【Transformation 5】 (In the above general formula (6), R ａ (This represents an alkyl group having 1 to 18 carbon atoms or an aryl group having 6 to 14 carbon atoms.) 【Transformation 6】 (In the general formula (7) above, O• represents an oxyl group.)

5. A lens resin composition according to claim 1, 2, or 4, A lens resin composition in which the content of the stabilizer is 0.01 parts by mass or more and 5.0 parts by mass or less per 100 parts by mass of the epoxy compound (Y).

6. A lens resin composition according to claim 1, 2, or 4, A resin composition for lenses in which the epoxy compound (Y) is represented by the following general formula (2). 【Transformation 7】 (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, and n is an average repeating number and represents a real number in the range of 0 to 30.)

7. A lens resin composition according to claim 1, 2, or 4, A lens resin composition wherein the photocationic polymerization initiator (X) comprises at least one anion selected from the anions represented by the following formula (3) and the anions represented by the following formula (4). 【Transformation 8】 【Chemistry 9】

8. A lens resin composition according to claim 1, 2, or 4, A lens resin composition wherein the photocationic polymerization initiator (X) contains a sulfonium ion as a cation.

9. A lens resin composition according to claim 1, 2, or 4, A lens resin composition further comprising a monofunctional epoxy compound (Z) represented by the following general formula (5). 【Chemistry 10】 (In the above general formula (5), A is selected from a single bond, an oxygen atom, and a sulfur atom, and R １０ (This is an alkylene having 1 to 8 carbon atoms, and any methylene group may be substituted with an oxygen atom.)

10. A lens resin composition according to claim 9, A lens resin composition wherein the monofunctional epoxy compound (Z) contains o-phenylphenol glycidyl ether.

11. A lens resin composition according to claim 1, 2, or 4, A lens resin composition further comprising an oxetane compound (W).

12. A lens resin composition according to claim 11, A lens resin composition wherein the oxetane compound (W) comprises a biphenyl-type oxetane compound.

13. A lens resin composition according to claim 1, 2, or 4, A lens resin composition wherein the viscosity of the lens resin composition, when measured with an E-type viscometer at a temperature of 25°C and a rotation speed of 2.5 rpm, is 100 mPa·s or more and 5000 mPa·s or less.

14. A lens resin composition according to claim 1, 2, or 4, The aforementioned lens resin composition was coated onto a glass substrate to a thickness of 250 μm, and the irradiation was performed at a wavelength of 365 nm, an irradiation intensity of 500 mW / cm, and an integrated irradiation dose of 6000 mJ / cm. ２ A lens resin composition in which a cured product obtained by UV exposure under the following conditions and heating under a nitrogen atmosphere at 120°C for 30 minutes has a refractive index of 1.55 or higher.

15. A lens resin composition according to claim 1, 2, or 4, The aforementioned lens resin composition was coated onto a glass substrate to a thickness of 250 μm, and the irradiation was performed at a wavelength of 365 nm, an irradiation intensity of 500 mW / cm, and an integrated irradiation dose of 6000 mJ / cm. ２ A lens resin composition in which a cured product obtained by UV exposure under the following conditions and heating under a nitrogen atmosphere at 120°C for 30 minutes has a light transmittance in the thickness direction of 70% or more, as measured using an ultraviolet-visible-near-infrared spectrophotometer under the following (measurement conditions). (Measurement conditions) Measurement method: transmission method Measurement wavelength: 400 nm Reference: Atmosphere Detector: Integrating sphere / photomultiplier tube (200 nm to 850 nm) Integrating sphere: PbS (850nm to 2600nm)

16. A lens resin composition according to claim 1, 2, or 4, The aforementioned lens resin composition was coated onto a glass substrate to a thickness of 250 μm, and the irradiation was performed at a wavelength of 365 nm, an irradiation intensity of 500 mW / cm, and an integrated irradiation dose of 6000 mJ / cm. ２ A lens resin composition in which a cured product obtained by UV exposure under the following conditions and heating under a nitrogen atmosphere at 120°C for 30 minutes has a light transmittance in the thickness direction of 70% or more, measured using an ultraviolet-visible-near-infrared spectrophotometer under the following conditions (measurement conditions) after the following (heat resistance test). (Measurement conditions) Measurement method: transmission method Measurement wavelength: 400 nm Reference: Atmosphere Detector: Integrating sphere / photomultiplier tube (200 nm to 850 nm) Integrating sphere: PbS (850nm to 2600nm) (Heat resistance test) The cured product is heated in an oven set to 125°C in an air atmosphere for 168 hours.

17. A lens resin composition according to claim 1, 2, or 4, which is used in wafer-level lenses.

18. A cured lens product obtained by curing the lens resin composition according to claim 1, 2, or 4.

19. A lens comprising the lens hardening material described in claim 18.

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