Cured product, optical element, optical equipment and imaging device

Abstract

To provide a cured product that has a high characteristic (high θg,F characteristic) of secondary dispersion characteristic (θg,F) of a refractive index, in other words, a high characteristic of chromatic aberration correction function, and has high transmittance.SOLUTION: A cured product of a resin composition contains a (meth)acrylate compound and a sulfur-containing compound having at least one thiol group in the molecule, wherein a content of the sulfur-containing compound is 30 mass% or less, and secondary dispersion characteristic of the cured product is 0.65 or more.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a cured product, an optical element, an optical instrument, and an imaging device. [Background technology]

[0002] In general, optical materials such as glass materials and organic resins have a gradually increasing refractive index toward the shorter wavelength side. The Abbe number (ν d ) and second-order dispersion characteristics (θ g,F ) are known. The Abbe number and secondary dispersion characteristics are values specific to each optical material, but in most cases they fall within a certain range. d Abbe number based on the d line) and second-order dispersion characteristics (θ g,F ) is expressed by the following formula: ν d =(n d -1) / (n F -n C ) θ g,F =(n g -n F ) / (n F -n C ) n d : Refractive index at wavelength 587.6 nm n F : Refractive index at wavelength 486.1 nm n C : Refractive index at wavelength 656.3 nm n g : Refractive index at wavelength 435.8 nm However, by carefully designing the composition (material type and molecular structure) of optical materials (glass materials, organic resins, etc.), optical materials with high second-order dispersion characteristics outside of this certain range of values have also been synthesized. Furthermore, when manufacturing optical elements having aspherical shapes or the like that offer excellent chromatic aberration correction capabilities, molding an organic resin onto a spherical glass or the like has the advantages of being more suitable for mass production, easier to mold, more flexible in shape, and lighter in weight than using glass material. However, the optical properties of conventional organic resins fall within the aforementioned fixed range, and few exhibit unique dispersion characteristics. Patent Document 1 discloses a cured product of a resin precursor containing a (meth)acrylate compound and a curable composition as a resin material with high secondary dispersion properties. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2019 / 069488 Summary of the Invention [Problem to be solved by the invention]

[0004] Although the cured product disclosed in Patent Document 1 has high secondary dispersion properties, the secondary dispersion properties are reduced compared to those of a cured product of the monomer component alone due to the components contained in the resin precursor to suppress precipitation of the monomer component. Furthermore, there is a demand for both high secondary dispersion properties and transmittance. In view of the above background art, the present invention aims to provide a method for determining the second-order dispersion characteristic of the refractive index (θ g,F ) is high (high θ g,F The present invention provides a resin composition having excellent chromatic aberration correcting properties, i.e., a high transmittance, a cured product of the resin composition, an optical element, and an optical instrument. [Means for solving the problem]

[0005] The cured product of the present invention is a cured product of a resin composition containing a (meth)acrylate compound and a sulfur-containing compound having at least one thiol group in the molecule, The content of the sulfur-containing compound is 1% by mass or more 30% by mass or less, The secondary dispersion characteristic of the cured product is 0.65 or more. the law of nature , The (meth)acrylate compound is a compound having an electron-withdrawing group or an electron-donating group bonded to at least two aryl groups, and having three or four benzene rings which may be bonded to each other. It is characterized by: [Effects of the Invention]

[0006] According to the present invention, the second-order dispersion characteristic of the refractive index (θ g,F ), i.e., an optical element containing a cured product having a high chromatic aberration correction function and a high transmittance can be provided. [Brief explanation of the drawings]

[0007] [Figure 1] 1 is a cross-sectional view in the thickness direction schematically illustrating the configuration of an example of an optical element of the present invention. [Figure 2] 1 is a cross-sectional view schematically showing the configuration of an imaging device using an optical element of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0008] Hereinafter, embodiments of the present invention will be described with reference to the drawings. The present invention is not limited to the following embodiments, and appropriate modifications and improvements to the following embodiments based on the ordinary knowledge of those skilled in the art are also included within the scope of the present invention, provided that they do not deviate from the spirit of the present invention. In this specification, the term "(meth)acrylate compound" refers to an acrylate compound and a methacrylate compound.

[0009] The present inventors have conducted extensive research to provide a resin composition having high secondary dispersion properties and high transmittance properties, and have found that adding a sulfur-containing compound having at least one thiol group in the molecule to a resin composition containing a (meth)acrylate compound exhibiting high secondary dispersion properties makes it possible to achieve both high secondary dispersion properties and high transmittance.

[0010] In general, compounds with long conjugated structures, such as aromatic compounds, have smaller band gaps than general-purpose materials, resulting in absorption edges in the ultraviolet region closer to the visible light region. As a result, compounds with long conjugated structures have high refractive indices and high second-order dispersion characteristics. However, simply linking aromatic compounds to construct long conjugated structures does not produce practical materials. For example, large aromatic compounds present challenges in terms of synthesis, coloring, reduced transmittance at the short wavelength end of the visible light region, compatibility with other compounds, and crystal precipitation in compositions.

[0011] Therefore, when using them as optical materials, it is necessary to adjust the length of the conjugated structure to improve transmittance and suppress crystallinity. However, shortening the conjugated structure of aromatic compounds or widening the intermolecular distance by steric hindrance of the substituents in order to improve transmittance or suppress crystallinity results in a decrease in the refractive index and a deterioration in second-order dispersion characteristics. Furthermore, adding a resin to improve transmittance or suppress crystallinity also results in a decrease in the refractive index and a deterioration in second-order dispersion characteristics.

[0012] The inventors believe the following about the resin composition according to the present invention. We believe that the cured product of a resin composition containing a (meth)acrylate compound with high secondary dispersion and a sulfur-containing compound with at least one thiol group in the molecule exhibits improved transmittance due to the reduced cure shrinkage of the sulfur-containing compound. Furthermore, by limiting the amount of sulfur-containing compound in the resin composition to 30% by mass or less, high secondary dispersion properties can be maintained while achieving high transmittance. When other resin components are added to a resin composition containing a (meth)acrylate compound with high secondary dispersion, the secondary dispersion decreases with the amount of the other resin components. This is because, with increasing amounts of the other resin components, the probability of the other resin components reacting with each other becomes higher than the probability of reacting with the (meth)acrylate compound with high secondary dispersion, resulting in components with low secondary dispersion. Sulfur-containing compounds containing thiol groups selectively react with the (meth)acrylate compound due to the ene-thiol reaction that occurs with the (meth)acrylate compound during curing, such as photocuring. In other words, sulfur-containing compounds can suppress the generation of low secondary dispersion components due to sulfur-containing compounds, and since their contribution to secondary dispersion properties relative to the amount added is small compared to other resin components, it is thought that high secondary dispersion properties can be maintained and high transmittance can be obtained.

[0013] As a result, it is believed that by setting the amount of sulfur-containing compounds to 30 mass % or less, high transmittance can be obtained while maintaining high secondary dispersion properties.

[0014] (Meth)acrylate compounds The (meth)acrylate compound used in the present invention preferably has the following two characteristics (a) and (b). By having characteristics (a) and (b), it is possible to achieve both high secondary dispersion properties and high transmittance. Hereinafter, a (meth)acrylate compound having characteristics (a) and (b) will be referred to as "(meth)acrylate compound (A)." (a) At least two aryl groups have electron-withdrawing or electron-donating groups attached thereto. (b )Be The total number of benzene rings is 3 or 4. The benzene rings may be bonded to each other.

[0015] Examples of electron-withdrawing groups include carbonyl groups, sulfonyl groups, and imide groups. Examples of electron-donating groups include trivalent groups having a nitrogen atom. Preferred are sulfonyl groups and trivalent groups having a nitrogen atom. The three bonds of the nitrogen atom are bonded to aryl groups.

[0016] Examples of the (meth)acrylate compound (A) include (meth)acrylate compounds represented by the following general formula (1) or (2).

[0017] <Compound represented by general formula (1)> [ka]

[0018] (In general formula (1), R1 and R2 are each independently selected from a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, and a substituted or unsubstituted alkylene group having 1 to 8 carbon atoms and having an acryloyloxy group or a methacryloyloxy group. R3 to R 12 are each independently selected from a hydrogen atom, a trifluoromethyl group, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkylene group having an acryloyloxy group or a methacryloyloxy group, an acryloyloxy group or a methacryloyloxy group. However, R3 to R 12 At least one of R to R is a trifluoromethyl group. 12 At least one of the groups has an acryloyloxy group or a methacryloyloxy group.

[0019] [R1 and R2] In the general formula (1), examples of the substituted or unsubstituted alkyl group having 1 to 10 carbon atoms represented by R1 and R2 include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an n-pentyl group, an n-hexyl group, etc. g,FAs long as the desired properties are obtained, the group is not limited to these, but is preferably a methyl group, an ethyl group, an n-propyl group, or an n-butyl group.

[0020] In the general formula (1), examples of the unsubstituted alkylene group having 1 to 8 carbon atoms and having an acryloyloxy group or a methacryloyloxy group, represented by R1 and R2, include a methylene group, an ethylene group, an n-propylene group, an iso-propylene group, an n-butylene group, an n-pentylene group, and an n-hexylene group. g,F As long as the desired properties are obtained, the alkyl group is not limited to these, but is preferably a methylene group, an ethylene group, an n-propylene group, or an n-butylene group.

[0021] In general formula (1), examples of the alkylene group having 1 to 8 carbon atoms and substituted with an acryloyloxy group or a methacryloyloxy group, represented by R1 and R2, include a group derived by replacing at least one CH2 in the main chain of the alkylene group with an oxygen atom, and a group derived by replacing at least one CH2 in the main chain of the alkylene group with a sulfur atom, but are not limited to these as long as high secondary dispersion properties can be obtained.

[0022] [R3 to R 12 ] In general formula (1), R to R 12 Examples of the substituted or unsubstituted alkyl group represented by the formula (I) include a methyl group, an ethyl group, an n-propyl group, an n-butyl group, an isopropyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, etc., but are not limited to these as long as high secondary dispersion properties can be obtained. Methyl groups and ethyl groups are preferred.

[0023] In general formula (1), R to R 12 Examples of the unsubstituted alkylene group having an acryloyloxy group or a methacryloyloxy group represented by the formula (I) include a methylene group, an ethylene group, an n-propylene group, an n-butylene group, an n-pentylene group, an n-hexylene group, and the like. g,FAs long as the desired properties are obtained, the group is not limited to these, but is preferably a methylene group, an ethylene group, or an n-propylene group.

[0024] In general formula (1), R to R 12 Examples of the substituted alkylene group having an acryloyloxy group or a methacryloyloxy group represented by the formula (I) include a group derived by replacing at least one CH2 in the main chain of the alkylene group with an oxygen atom, a group derived by replacing at least one CH2 in the main chain of the alkylene group with a sulfur atom, and the like. g,F There is no limitation to these as long as the desired properties can be obtained.

[0025] <Compound represented by general formula (2)> [ka]

[0026] (In the above general formula (2), X and Y are S or O, respectively. R 21 When X is S, R is an alkyl group having 1 to 2 carbon atoms, and when X is O, R is a hydrogen atom or an alkyl group having 1 to 2 carbon atoms. 22 When Y is S, it is an alkyl group having 1 to 2 carbon atoms, and when Y is O, it is a hydrogen atom or an alkyl group having 1 to 2 carbon atoms. R 23 ~R 30 are each independently selected from a hydrogen atom and a methyl group. a and b are each an integer of 1 or 2. Z1 and Z2 are each a group represented by the following general formula (3). When a is 2, one of Z1 may be a methyl group. When b is 2, one of Z2 may be a methyl group.

[0027] [ka]

[0028] (In general formula (3), * represents a bond. m is selected from 0 and 1. W is a hydrogen atom or a methyl group. V is selected from groups represented by the following general formulas (4) to (6). -OC n H 2n -O-** ···(4) -SC n H 2n -S-** ···(5) -SC n H 2n -O-** ···(6) In the general formulae (4) to (6), * represents a bond to the alkylene group, and ** represents a bond to the (meth)acryloyl group. n is selected from 2, 3, and 4. -C n H 2n At least one hydrogen atom of - may be substituted with a methyl group.

[0029] [X and Y] In general formula (2), by making X and Y electron-donating elements, the state of the conjugated structure of the compound is improved, and high secondary dispersion characteristics are obtained. Furthermore, in consideration of ease of synthesis and stability of the compound, X and Y are each S or O. Preferably, in consideration of ease of procurement of raw materials, X and Y are each O. Furthermore, in consideration of ease of synthesis, it is preferable that X and Y are the same.

[0030] [R 21 and R 22 ] In general formula (2), R 21 and R 22 are each a hydrogen atom or an alkyl group having 1 to 2 carbon atoms in order to prevent deterioration of optical properties. However, when X is S, R 21 is an alkyl group having 1 to 2 carbon atoms, and when Y is S, R 22 is an alkyl group having 1 to 2 carbon atoms. 21 and R 22is preferably an alkyl group having 1 to 2 carbon atoms. The alkyl group having 1 to 2 carbon atoms is a methyl group or an ethyl group. 21 and R 22 may be the same or different, but are preferably the same in consideration of ease of synthesis.

[0031] [R 23 ~R 30 ] In general formula (2), R 23 ~R 30 are each independently selected from a hydrogen atom and a methyl group. 23 ~R 30 is preferably a hydrogen atom.

[0032] [a and b] In general formula (2), a and b are each an integer of 1 or 2. When a is 2, two Z1s may be the same or different. When b is 2, two Z2s may be the same or different. In consideration of ease of synthesis, it is preferable that a and b are each 1.

[0033] [Z1 and Z2] In general formula (2), Z1 and Z2 are each a group represented by general formula (3). When a is 2, one of Z1 may be a methyl group. When b is 2, one of Z2 may be a methyl group. Z1 and Z2 may be the same or different, but are preferably the same in consideration of ease of synthesis.

[0034] [m] In the general formula (3), m is one selected from 0 and 1, taking into consideration the ease of obtaining raw materials. Preferably, m is 0.

[0035] [W] In the general formula (3), W is a hydrogen atom or a methyl group, taking into consideration the reactivity of the polymerization reaction and the ease of procuring raw materials.

[0036] [V] In general formula (3), V is selected from the groups represented by the following general formulae (4) to (6) in order to suppress deterioration of the optical properties of the resulting molded article. -OC n H 2n -O-** ···(4) -SC n H 2n -S-** ···(5) -SC n H 2n -O-** ···(6) In the general formulae (4) to (6), * represents a bond to the alkylene group, and ** represents a bond to the (meth)acryloyl group. n is selected from 2, 3, and 4. n H 2n At least one hydrogen atom of - may be substituted with a methyl group. The number of methyl groups substituted for hydrogen atoms is preferably 1 to 2 in order to suppress deterioration of optical properties.

[0037] In consideration of ease of raw material procurement and synthesis, V is preferably a group represented by general formula (4). More preferred are *-O-CH(CH3)-CH2-O-**, *-O-CH2-CH(CH3)-O-**, *-O-CH2-CH2-CH2-O-**, *-O-CH2-CH(CH3)-CH2-O-**, *-O-CH2-CH(CH3)-CH2-O-**, and *-O-CH2-C(CH3)2-CH2-O-**.

[0038] <Example> Specific examples of the (meth)acrylate compound used in the present invention are shown below. However, the (meth)acrylate compound used in the present invention is not limited to these. A plurality of (meth)acrylate compounds may be used in combination. That is, the cured product according to the present invention (the polymer of the resin composition described below) may be a homopolymer or copolymer of the (meth)acrylate compound.

[0039] In addition, the crossed sign (-) and (|) at the -O-C2H3(CH3)-O- position in the formula of exemplary compound M6 indicates that CH3 is a mixture of those bonded to the carbon atom on the right side or the carbon atom on the left side.

[0040] [ka]

[0041] [ka]

[0042] <Manufacturing method> The method for producing the (meth)acrylate compound of the present invention will be described below with reference to an example.

[0043] The method for producing the (meth)acrylate compound is not particularly limited, and any production method can be adopted, and the compound can be synthesized using a known synthesis method. For example, the compound represented by general formula (1) can be synthesized using the known synthesis method described in JP-A-2018-165355, and the compound represented by general formula (2) can be synthesized using the known synthesis method described in JP-A-2014-43565.

[0044] There are two methods for introducing a polymerizable functional group into a (meth)acrylate compound. One is a method for directly introducing the polymerizable functional group to form a (meth)acrylate compound. The other is a method for introducing a structure having a polymerizable functional group or a functional group of a precursor of a polymerizable functional group into a precursor of a (meth)acrylate compound. The latter method includes, for example, a method for introducing a functional group-containing aryl group using a coupling reaction based on a monoarylamine derivative using a metal catalyst and a base.

[0045] The following methods can be used to introduce an unsaturated hydrocarbon group (e.g., an acrylic group or a methacrylic group) into a (meth)acrylate compound: a method in which a (meth)acrylate is reacted with a precursor of a (meth)acrylate compound having a hydroxy group, or a method in which a polymerizable functional group is directly introduced to form a (meth)acrylate compound.

[0046] Metal-catalyzed coupling reactions can be performed in any desired manner, including the Ullmann reaction using copper, the Buchwald-Hartwig reaction using amines, the Suzuki coupling using boric acid, the Stille coupling using organotin, and the Negishi coupling using organozinc.

[0047] Any method can be selected for the (meth)acrylate reaction. Typical methods include esterifying a hydroxyl group using a (meth)acrylic acid halide or (meth)acrylic anhydride, and transesterification using a lower alcohol ester of (meth)acrylic acid. Other suitable methods include direct esterification, in which (meth)acrylic acid and the diol undergo dehydration condensation using a dehydration condensing agent such as N,N'-dicyclohexylcarbodiimide, and heating (meth)acrylic acid and the diol in the presence of a dehydrating agent such as sulfuric acid.

[0048] A polymerization inhibitor may also be used to prevent polymerization of the (meth)acrylate compound during reaction or storage. Usable examples include hydroquinones such as p-benzoquinone, hydroquinone, hydroquinone monomethyl ether, and 2,5-diphenylparabenzoquinone, and N-oxy radicals such as tetramethylpiperidinyl-N-oxy radical (TEMPO). Other examples include substituted catechols such as t-butylcatechol, amines such as phenothiazine, diphenylamine, and phenyl-β-naphthylamine, nitrosobenzene, picric acid, molecular oxygen, sulfur, and copper(II) chloride. Among these, hydroquinones, phenothiazine, and N-oxy radicals are preferred in terms of versatility and polymerization inhibition, with hydroquinones being particularly preferred.

[0049] The amount of polymerization inhibitor used relative to the (meth)acrylate compound has a lower limit of usually 10 ppm or more, preferably 50 ppm or more, and an upper limit of usually 10,000 ppm or less, preferably 1,000 ppm or less. If the amount is too small, the effect as a polymerization inhibitor will not be exhibited, or even if it is exhibited, the effect will be small, and polymerization may proceed during the reaction or during concentration in a post-treatment step. Conversely, if the amount is too large, it may become an impurity when producing a resin composition described below, or may have adverse effects such as inhibiting polymerization reactivity, which is not preferable.

[0050] ≪Resin composition≫ The resin composition of the present invention contains a (meth)acrylate compound and a sulfur-containing compound having at least one thiol group in the molecule.

[0051] The content of the (meth)acrylate compound contained in the resin composition, preferably the content of the (meth)acrylate compound (A), is preferably 1.0 mass% or more and 99 mass% or less, more preferably 50 mass% or more and 99 mass% or less, based on the total mass of the resin composition.

[0052] <Sulfur-containing compounds> The content of the sulfur-containing compound of the present invention is 30% by mass or less, preferably 0.01% by mass or more and 30% by mass or less. The content of the sulfur-containing compound is preferably 1% by mass or more and 15% by mass or less in consideration of the refractive index characteristics and transmittance of the resulting resin composition, and more preferably 2% by mass or more and 10% by mass or less in consideration of the brittleness of the resulting molded product.

[0053] The sulfur-containing compound may be used alone or in combination of two or more kinds. There is no particular limitation on the sulfur-containing compound as long as it does not significantly affect the optical properties of the molded article. Examples of sulfur-containing compounds include ethanethiol, 1-propanethiol, 1-butanethiol, 1-pentanethiol, 1-hexanethiol, 1-heptanethiol, 1-octanethiol, 1-decanethiol, 1-undecanethiol, 1-dodecanethiol, 1-tetradecanethiol, 1-pentadecanethiol, 1-hexadecanethiol, 1-octadecanethiol, 1-eicosanethiol, 1-docosanethiol, cyclohexanethiol, cyclopentanethiol, 2-propanethiol, 2-butanethiol, isobutyl mercaptan, isopentanethiol, 2-methyl-2-propanethiol, 2-methyl-1-butanethiol, 2-ethyl-1-hexanethiol, 3-methyl-2-butanethiol, and tert-dodecyl mercaptan. , tert-tetradecanethiol, tert-hexadecanethiol, 1,2-ethanedithiol, 1,2-propanedithiol, 1,3-propanedithiol, 1,2-butanedithiol, 1,4-butanedithiol, 2,3-butanedithiol, 1,5-pentanedithiol, 1,6-hexanedithiol, 1,8-octanedithiol, 3,6-dioxa-1,8-octanedithiol Thiol, 3,7-dithia-1,9-nonanedithiol, 1,10-decanedithiol, bis(2-mercaptoethyl) ether, bis(2-mercaptoethyl) sulfide, 1,4-bis(3-mercaptobutyryloxy)butane, 1,3,5-tris(2-(3-sulfanylbutanoyloxy)ethyl)-1,3,5-triazinane-2,4,6-trione, trimethylolpropane nt Tris(3-mercaptobutyrate), Pentaerythritol Ruthe Trachys(3-mercaptobutyrate) 、Octadecyl 3-mercaptopropionate, 2-ethylhexyl-3-mercaptopropionate, n-octyl-3-mercaptopropionate, methoxybutyl-3-mercaptopropionate, stearyl-3-mercaptopropionate, ethylene bis(thioglycolate), 1,4-butanediol bis(thioglycolate), ethylene glycol bis(3-mercaptopropionate), tetraethylene glycol ruby Examples of the esters of 2-(3-mercaptopropionyloxy)ethyl isocyanurate include, but are not limited to, tris(3-mercaptopropionate), trimethylolpropane tris(thioglycolate), trimethylolpropane tris(3-mercaptopropionate), tris[2-(3-mercaptopropionyloxy)ethyl]isocyanurate, pentaerythritol tetrakis(mercaptoacetate), pentaerythritol tetra(3-mercaptopropionate), dipentaerythritol hexakis(3-mercaptopropionate), and the like.

[0054] <Other ingredients> The resin composition used in the present invention may contain a polymerization initiator, a polymerization inhibitor, and, if necessary, a photosensitizer, a light stabilizer, a heat stabilizer, an antioxidant, or other resin components.

[0055] [Polymerization initiator] Examples of the polymerization initiator include, but are not limited to, those that generate radical species or cation species upon irradiation with light, and those that generate radical species upon heat.

[0056] Examples of polymerization initiators that generate radical species upon irradiation with light include 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-1-butanone and 1-hydroxycyclohexylphenyl ketone. Other examples include 2-hydroxy-2-methyl-1-phenylpropan-1-one, bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, 4-phenylbenzophenone, and 4-phenoxybenzophenone. Other examples include, but are not limited to, 4,4'-diphenylbenzophenone and 4,4'-diphenoxybenzophenone.

[0057] Furthermore, examples of suitable polymerization initiators that generate cationic species upon irradiation with light include, but are not limited to, iodonium(4-methylphenyl)[4-(2-methylpropyl)phenyl]-hexafluorophosphate.

[0058] Furthermore, examples of polymerization initiators that generate radical species by heat include azo compounds such as azobisisobutylnitrile (AIBN), benzoyl peroxide, t-butyl peroxypivalate, t-butyl peroxyneohexanoate, etc. Also included are peroxides such as t-hexyl peroxyneohexanoate, t-butyl peroxyneodecanoate, t-hexyl peroxyneodecanoate, cumyl peroxyneohexanoate, etc., but are not limited to these.

[0059] When polymerization is initiated by irradiation with ultraviolet light or the like, known sensitizers can also be used. Examples of sensitizers include benzophenone, 4,4-diethylaminobenzophenone, and 1-hydroxycyclohexylphenyl ketone. Other examples include isoamyl p-dimethylaminobenzoate, methyl 4-dimethylaminobenzoate, benzoin, benzoin ethyl ether, benzoin isobutyl ether, benzoin isopropyl ether, and 2,2-diethoxyacetophenone. Other examples include, but are not limited to, methyl o-benzoylbenzoate, 2-hydroxy-2-methyl-1-phenylpropan-1-one, and acylphosphine oxide.

[0060] The content ratio of the photopolymerization initiator to the polymerizable component can be appropriately selected depending on the amount of light irradiation and the additional heating temperature, and can also be adjusted depending on the target average molecular weight of the resulting polymer.

[0061] The content of the photopolymerization initiator used in the polymerization (curing) and molding of the resin composition used in the present invention is preferably in the range of 0.01% by mass to 10.00% by mass based on the total amount of polymerizable components. Depending on the reactivity of the resin and the wavelength of light irradiation, a single type of photopolymerization initiator can be used, or two or more types can be used in combination.

[0062] [Polymerization inhibitor] Examples of the polymerization inhibitor include those described in "<(Meth)acrylate Compound> <Production Method>." The content of the polymerization inhibitor is as described in "<(Meth)acrylate Compound> <Production Method>."

[0063] [Light resistance stabilizer] There are no particular limitations on the light resistance stabilizer, as long as it does not significantly affect the optical properties of the cured product. Representative examples include benzotriazole-based materials, such as 2-(2H-benzotriazol-2-yl)-p-cresol and 2-(2H-benzotriazol-2-yl)-4,6-bis(1-methyl-1-phenylethyl)phenol. Other examples include 2-[5-chloro(2H)-benzotriazol-2-yl]-4-methyl-6-(tert-butyl)phenol and 2-(2H-benzotriazol-2-yl)-4,6-di-tert-pentylphenol. Other examples include 2-(2H-benzotriazol-2-yl)-4-(1,1,3,3-tetramethylbutyl)phenol. Other examples include 2,2'-methylenedibis[6-(2H-benzotriazol-2-yl)-4-(1,1,3,3-tetramethylbutyl)]phenol and 2-(2H-benzotriazol-2-yl)-6-dodecyl-4-methylphenol. Other examples include cyanoacrylate-based materials such as ethyl 2-cyano-3,3-diphenylacrylate and 2-ethylhexyl 2-cyano-3,3-diphenylacrylate. Other examples include triazine-based materials, benzophenone-based materials such as octabenzone and 2,2'-4,4'-tetrahydrobenzophenone. The light resistance stabilizer may also function as a photosensitizer, in which case it may not be added.

[0064] The content of the light resistance stabilizer used in the polymerization (curing) and molding of the resin composition used in the present invention is preferably in the range of 0.01% by mass to 10.00% by mass based on the total amount of polymerizable components.

[0065] [Heat stabilizer] The heat resistance stabilizer is not particularly limited as long as it does not significantly affect the optical properties of the cured product. For example, hindered phenol materials include pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)]propionate. Other examples include octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, benzenepropanoic acid 3,5-bis(1,1-dimethylethyl)-4-hydroxy, C7-C9 side chain alkyl ester, etc. Other examples include 4,6-bis(octylthiomethyl)-o-cresol, 4,6-bis(dodecylthiomethyl)-o-cresol, ethylenebis(oxyethylene)bis[3-(5-tert-butyl-4-hydroxy-m-tolyl)]propionate, etc. Other examples include hexamethylenebis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)]propionate, etc. Phosphorus-based materials such as tris(2,4-di-tert-butylphenyl)phosphite, and sulfur-based materials such as dioctadecyl 3,3′-thiodipropionate can also be used.

[0066] The content of the heat resistance stabilizer used in the polymerization (curing) and molding of the resin composition used in the present invention is preferably in the range of 0.01% by mass to 10.00% by mass based on the total amount of polymerizable components.

[0067] [Antioxidants] The antioxidant is not particularly limited as long as it does not significantly affect the optical properties of the molded article, and representative examples include hindered amine-based materials, such as bis(2,2,6,6-tetramethyl-4-piperidyl) sebacate, and bis(1,2,2,6,6-pentamethyl-4-piperidyl)[[3,5-bis(1,1-dimethylethyl)-4-hydroxyphenyl]methyl]butyl malonate.

[0068] The content of the antioxidant used in the polymerization (curing) and molding of the resin composition used in the present invention is preferably in the range of 0.01% by mass to 10.00% by mass based on the total amount of polymerizable components.

[0069] [Other resin components] The other resin components contained in the resin composition used in the present invention are not particularly limited, and examples thereof include 1,3-adamantanediol dimethacrylate, 1,3-adamantanedimethanol dimethacrylate, tricyclodecane dimethanol diacrylate, pentaerythritol tetraacrylate, propoxylated neopentyl glycol diacrylate, dipropylene glycol diacrylate, ethoxylated bisphenol A dimethacrylate, tris(2-hydroxyethyl)isocyanurate triacrylate, 2(2-ethoxyethoxy)ethyl acrylate, stearyl acrylate, tetrahydrofurfuryl acrylate, 2-phenoxyethyl acrylate, isodecyl acrylate, isobornyl acrylate, isobornyl methacrylate, 1,3-butylene glycol diacrylate, 1,4-butanediol diacrylate, diethylene glycol Lithium diacrylate, 1,6-hexanediol diacrylate, triethylene glycol diacrylate, tripropylene glycol diacrylate, dipropylene glycol diacrylate, triethylene glycol dimethacrylate, ethylene glycol dimethacrylate, tetraethylene glycol dimethacrylate, 1,4-butanediol dimethacrylate, diethylene glycol dimethacrylate, 1,6-hexanediol dimethacrylate, tripropylene glycol dimethacrylate, dipropylene glycol dimethacrylate, trimethylolpropane trimethacrylate, 9,9-bis[4-(2-acryloyloxyethoxy)phenyl]fluorene, 9,9-bis[4-(2-methacryloyloxyethoxy)phenyl]fluorene, 9,9-Bis[4-(2-methacryloyloxy)phenyl]fluorene, benzyl acrylate, benzyl methacrylate, butoxyethyl acrylate, butoxymethyl methacrylate, cyclohexyl acrylate, cyclohexyl methacrylate, 2-hydroxyethyl acrylate, 2-hydroxymethyl methacrylate, glycidyl acrylate, glycidyl methacrylate, phenoxyethyl acrylate, phenoxyethyl methacrylate, phenyl methacrylate, ethylene glycol diacrylate, ethylene glycol dimethacrylate, diethylene glycol diacrylate, diethylene glycol dimethacrylate, triethylene glycol diacrylate, triethylene glycol dimethacrylate, tetraethylene glycol diacrylate, tetraethylene glycol dimethacrylate, polyethylene glycol diacrylate, polyethylene glycol dimethacrylate, neopentyl glycol diacrylate, neopentyl glycol dimethacrylate acrylate, ethylene glycol bisglycidyl acrylate, ethylene glycol bisglycidyl methacrylate, bisphenol A diacrylate, bisphenol A dimethacrylate, 2,2-bis(4-acryloxyethoxyphenyl)propane, 2,2-bis(4-methacryloxyethoxyphenyl)propane, 2,2-bis(4-acryloxydiethoxyphenyl)propane, 2,2-bis(4-methacryloxydiethoxyphenyl)propane, bisphenol F diacrylate, bis Phenol F dimethacrylate, 1,1-bis(4-acryloxyethoxyphenyl)methane, 1,1-bis(4-methacryloxyethoxyphenyl)methane, 1,1-bis(4-acryloxydiethoxyphenyl)methane, 1,1-bis(4-methacryloxydiethoxyphenyl)methane, 1,1-bis(4-acryloxyethoxyphenyl)sulfone, 1,1-bis(4-methacryloxyethoxyphenyl)sulfone, 1,1-bis(4-acryloxydiethoxyphenyl)sulfone, 1,1-Bis(4-methacryloxydiethoxyphenyl)sulfone, dimethyloltricyclodecane diacrylate, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, glycerol diacrylate, glycerol dimethacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, pentaerythritol tetramethacrylate, methyl thioacrylate, methyl thiomethacrylate, phenyl thioacrylate, benzyl thiomethacrylate, xylylenedithiol diacrylate, xylylenedithiol Examples of suitable resins include (meth)acrylate compounds such as mercaptoethyl sulfide dimethacrylate, mercaptoethyl sulfide diacrylate, and mercaptoethyl sulfide dimethacrylate; allyl compounds such as allyl glycidyl ether, diallyl phthalate, diallyl terephthalate, diallyl isophthalate, diallyl carbonate, and diethylene glycol bisallyl carbonate; vinyl compounds such as styrene, chlorostyrene, methylstyrene, bromostyrene, dibromostyrene, divinylbenzene, and 3,9-divinylspirobi(m-dioxane); and diisopropenylbenzene, but are not limited to these. From the viewpoint of excellent optical properties and moldability, acrylate resins and methacrylate resins are particularly preferred.

[0070] The other resin component may also be a thermoplastic resin, for example, a polyolefin resin such as an ethylene homopolymer, a random or block copolymer of ethylene with one or more α-olefins such as propylene, 1-butene, 1-pentene, 1-hexene, or 4-methyl-1-pentene, a random or block copolymer of ethylene with one or more α-olefins such as vinyl acetate, acrylic acid, methacrylic acid, methyl acrylate, or methyl methacrylate, a propylene homopolymer, a random or block copolymer of propylene with one or more α-olefins other than propylene such as 1-butene, 1-pentene, 1-hexene, or 4-methyl-1-pentene, a 1-butene homopolymer, an ionomer resin, or a mixture of these polymers; a hydrocarbon atom-based resin such as a petroleum resin or a terpene resin. Examples of suitable resins include: polyester resins such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate; polyamide resins such as nylon 6, nylon 66, nylon 11, nylon 12, nylon 610, nylon 6 / 66, nylon 66 / 610, and nylon MXD; acrylic resins such as polymethyl methacrylate; styrene-acrylonitrile resins such as polystyrene, styrene-acrylonitrile copolymer, styrene-acrylonitrile-butadiene copolymer, and polyacrylonitrile; polyvinyl alcohol resins such as polyvinyl alcohol and ethylene-vinyl alcohol copolymer; polycarbonate resins; polyketone resins; polymethylene oxide resins; polysulfone resins; polyimide resins; and polyamide-imide resins. These resins can be used alone or in combination of two or more.

[0071] The content of other resin components contained in the resin composition is preferably 0.01% by mass or more and 99% by mass or less. Considering the refractive index characteristics of the resulting resin composition and the brittleness of the molded product, 0.01% by mass or more and 50% by mass or less is more preferable. Furthermore, the content is more preferably 0.01% by mass or more and 20.0% by mass or less. Furthermore, in order to maintain secondary dispersion characteristics and transmittance, it is more preferable to contain acrylate resins and methacrylate resins in amounts of 0.01% by mass or more and 20.0% by mass or less.

[0072] ≪Cured product≫ The cured product of the present invention is a cured product of the resin composition of the present invention, in which the content of the sulfur-containing compound is 30 mass% or less and the secondary dispersion characteristic of the cured product is 0.65 or more, and more preferably 0.70 or more.

[0073] The content of the sulfur-containing compound in the cured product is preferably from 0.01% by mass to 30% by mass, more preferably from 1% by mass to 15% by mass in consideration of the refractive index characteristics and transmittance of the cured product, and even more preferably from 2% by mass to 10% by mass in consideration of the brittleness of the cured product.

[0074] Secondary dispersion characteristics of the cured product (θ g,F ) is expressed by the following formula, where the refractive index is the refractive index at room temperature (23°C). θ g,F =(n g -n F ) / (n F -n C ) n d : Refractive index at wavelength 587.6 nm n F : Refractive index at wavelength 486.1 nm n C : Refractive index at wavelength 656.3 nm n g : Refractive index at wavelength 435.8 nm The ratio of carbon atoms to sulfur atoms (carbon atoms / sulfur atoms) contained in the cured product of the present invention is preferably 15 or more and 130 or less. In consideration of the transmittance of the obtained cured product, the ratio of carbon atoms to sulfur atoms is preferably 30 or more and less than 100, and in consideration of the brittleness of the cured product, it is more preferably 50 or more and less than 100.

[0075] <Optical elements> Next, an optical element according to the present invention will be described with reference to the drawings.

[0076] The optical element of the present invention is characterized by comprising the cured product of the present invention. The cured product of the present invention exhibits high second-order dispersion characteristics of 0.65 or more, and therefore, in the optical element of the present invention, chromatic aberration can be efficiently eliminated.

[0077] 1(a) shows a cross-sectional view of an optical element according to an embodiment of the present invention, taken along the thickness direction, in which a thin film of a cured product 1 is provided on one surface of a transparent substrate 2. In FIG.

[0078] The transparent substrate 2 can be made of a transparent resin or transparent glass. In this specification, "transparent" means that the transmittance over the entire visible light range (light having a wavelength in the range of 380 nm to 780 nm) is 30% or more. The transparent substrate 2 is preferably made of glass, and examples of materials that can be used include common optical glasses such as silicate glass, borosilicate glass, and phosphate glass, as well as quartz glass and glass ceramics. The transparent substrate 2 is preferably circular in plan view.

[0079] 1(a) may be produced, for example, by forming a thin layer structure on the transparent substrate 2. Specifically, a mold made of a metal material is placed at a certain distance from the transparent substrate 2, and a fluid resin composition is filled into the gap between the mold and the transparent substrate 2, and then the mold is lightly pressed down to form the mold. If necessary, the resin composition is polymerized while maintaining this state.

[0080] The light irradiation used for the polymerization reaction is carried out using light of a suitable wavelength, typically ultraviolet or visible light, depending on the mechanism resulting from radical generation using a photopolymerization initiator. For example, light is uniformly irradiated onto raw materials such as monomers of the resin composition through a light-transmitting material used as the transparent substrate 2. The amount of light irradiation is appropriately selected depending on the mechanism resulting from radical generation using the photopolymerization initiator and the content ratio of the photopolymerization initiator contained.

[0081] On the other hand, when curing a resin composition by such a photopolymerization reaction, it is more preferable that the irradiated light is uniformly applied to the entire molded resin composition. Therefore, it is more preferable to select light of a wavelength that allows uniform irradiation through the light-transmitting material used for the transparent substrate 2. In this case, it is more suitable for the present invention to reduce the thickness of the cured product 1 formed on the transparent substrate 2.

[0082] In addition, in FIG. 1(b), a thin film of a cured product 1 obtained by curing the above-mentioned resin composition is sandwiched between transparent substrates 2 and 3. In FIG. 1(b), the transparent substrates 2 and 3 each have a concave surface on the opposing side and are in contact with each other at their peripheries, and the cured product 1 is like a lens with convex surfaces on both sides. The transparent substrates 2 and 3 can be made of a transparent resin or transparent glass, preferably glass. Examples of glass that can be used include general optical glass, such as silicate glass, borosilicate glass, and phosphate glass, as well as quartz glass and glass ceramics. The transparent substrates 2 and 3 are preferably circular when viewed from above.

[0083] 1(b), for example, the resin composition is poured between transparent substrates 2 and 3 and gently pressed down to form the resin composition. While maintaining this state, the resin composition is photopolymerized. This results in a laminate in which the cured product 1 is sandwiched between the transparent substrates 2 and 3.

[0084] Similarly, a molded body can also be produced by a thermal polymerization method. In this case, it is desirable to make the overall temperature more uniform, and it is more suitable for the present invention to reduce the total thickness of the molded body of the resin composition formed on the substrate of the light-transmitting material. Furthermore, when the total thickness of the molded body of the resin composition to be formed is increased, it is necessary to select the irradiation amount, irradiation intensity, light source, etc., taking into consideration the film thickness, absorption of the resin component, and absorption of the microparticle component.

[0085] Specific application examples of the optical element of the present invention will be described. Specific application examples include lenses constituting optical equipment (photography optical systems) for cameras and video cameras, and lenses constituting optical equipment (projection optical systems) for liquid crystal projectors. The optical element can also be used as a pickup lens for DVD recorders and the like. These optical systems have multiple lenses arranged in a housing, and at least one of the multiple lenses can be the optical element of the present invention.

[0086] <Optical equipment, imaging devices> The optical device of the present invention has a housing and an optical system having a plurality of lenses arranged in the housing, and at least one of the plurality of lenses is the optical element of the present invention.

[0087] The imaging device of the present invention has a housing, an optical system having a plurality of lenses arranged within the housing, and an imaging element that receives light that has passed through the optical system, and at least one of the plurality of lenses is the optical element of the present invention.

[0088] Fig. 2 shows a preferred embodiment of an imaging device using the optical element of the present invention, and illustrates the configuration of a single-lens reflex digital camera 10. Fig. 2 is a schematic cross-sectional view including the optical axis of the optical element used. In Fig. 2, a camera body 12 is coupled to a lens barrel 11, which is an optical device, and the lens barrel 11 is a so-called interchangeable lens that can be attached to and detached from the camera body 12.

[0089] Light from a subject is photographed via an optical system consisting of multiple lenses 13, 15, etc., arranged on the optical axis of the photographing optical system within housing 30 of lens barrel 11. The optical element of the present invention can be used, for example, for lenses 13, 15. Here, lens 15 is supported by inner barrel 14 and is movably supported relative to the outer barrel of lens barrel 11 for focusing and zooming.

[0090] During the observation period before shooting, light from the subject is reflected by the main mirror 17 inside the camera body housing 31, passes through a prism 21, and then is projected to the photographer through a viewfinder lens 22. The main mirror 17 is, for example, a half mirror, and light passing through the main mirror 17 is reflected by a sub-mirror 18 toward an AF (autofocus) unit 23. This reflected light is used, for example, for distance measurement. The main mirror 17 is attached and supported by a main mirror holder 40, for example, by adhesive. During shooting, a drive mechanism (not shown) moves the main mirror 17 and sub-mirror 18 out of the optical path, opens the shutter 19, and allows the image sensor 20 to receive light that has entered through the lens barrel 11 and passed through the shooting optical system, forming a shooting light image. The aperture 16 is configured so that the brightness and depth of focus during shooting can be changed by changing the aperture area.

[0091] Although the imaging device has been described above using a single-lens reflex digital camera, the optical element of the present invention can also be used in smartphones, compact digital cameras, and the like. [Example]

[0092] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the following examples in any way as long as it does not deviate from the gist of the invention.

[0093] <Synthesis of (meth)acrylate compound (A)> <Synthesis of exemplary compounds M1, M2, M5, and M8> Exemplary compounds M1 and M2 were synthesized as compounds represented by general formula (1), and exemplary compounds M5 and M8 were synthesized as compounds represented by general formula (2). These compounds were synthesized based on the descriptions in JP-A-2018-165355 and JP-A-2014-043565.

[0094] <Synthesis of Exemplary Compound M10> (1) Synthesis of intermediate of exemplary compound M10 Under a nitrogen atmosphere, a 500 mL three-neck flask was charged with 1.58 g of 4-chlorobenzotrifluoride, 8.0 g of 2-(4-aminophenyl)ethanol, 66.50 g of cesium carbonate, and 0.33 g of bis(dibenzylideneacetone)palladium. 0.56 g of 2-dicyclohexylphosphino-2',4',6'-triisopropylbiphenyl and 280 mL of ortho-xylene were also added. The mixture was heated to 120 °C and stirred at that temperature for 6 hours. After cooling to room temperature (25 °C), the organic phase was extracted with ethyl acetate. The resulting organic phase was washed with saturated brine and water, and then dried over anhydrous magnesium sulfate. The resulting crude product was purified by column chromatography to obtain 14.3 g (57% yield) of the exemplary compound M10 intermediate.

[0095] (2) Synthesis of exemplary compound M10 Under a nitrogen atmosphere, 10.0 g of the exemplary compound M10 intermediate, 350 mL of tetrahydrofuran, 0.88 g of hydroquinone monomethyl ether (MEHQ), and 13.0 mL of triethylamine were added to a 500 mL three-neck flask. Then, 12.0 g of methacrylic anhydride was added dropwise, and the mixture was heated and refluxed with stirring for 20 hours. The reaction solution was diluted with toluene, and the resulting organic phase was washed with acidic and basic aqueous solutions, followed by drying with saturated saline and anhydrous magnesium sulfate. The solvent was removed, and the resulting crude product was purified by silica gel chromatography to obtain 6.5 g of exemplary compound M10 (yield 56%).

[0096] ≪Sulfurized compound≫ Sulfur-containing compound S1: bis(2-mercaptoethyl) sulfide (Tokyo Chemical Industry Co., Ltd.) Sulfur-containing compound S2: 1,4-butanediol bis(thioglycolate) ) (Tokyo Chemical Industry Co., Ltd.) Sulfur-containing compound S3: Trimethylolpropane tris(3-mercaptopropionate) (Tokyo Chemical Industry Co., Ltd.) Sulfur-containing compound S4: Pentaerythritol tetra(3-mercaptopropionate) (Tokyo Chemical Industry Co., Ltd.) Sulfur-containing compound S5: Dodecanethiol (Tokyo Chemical Industry Co., Ltd.)

[0097] <Other resin components> Other resin components: R1: 1,6-hexanediol methacrylate (Tokyo Chemical Industry Co., Ltd.) Other resin component R2: Triethylene glycol dimethacrylate (Tokyo Chemical Industry Co., Ltd.) Other resin component R3: Tricyclodecane dimethanol diacrylate (manufactured by Shin-Nakamura Chemical Co., Ltd.) <Polymerization aid> Polymerization inhibitor I1: Methoxyphenol (Fujifilm Wako Pure Chemical Industries, Ltd.) Polymerization initiator I2: "Irgacure TPO" diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide (manufactured by BASF)

[0098] Example 1 (1) Preparation of resin composition A resin composition was prepared by mixing exemplary compound M1, sulfur-containing compound S1, and other resin components R1, I1, and I2 in a mass ratio of 81:10:9:0.1:0.2.

[0099] (2) Refractive index and second-order dispersion characteristics (θ g,F ) measurement The resin composition was placed on a 500 μm thick spacer on a 1 mm thick high refractive index glass ("S-TIH11" manufactured by HOYA Corporation). Next, quartz glass was placed on the resin composition to be measured and spread to a thickness of 500 μm via the spacer. The resin composition sandwiched between the two glass substrates was cured by irradiating the sample with a high-pressure mercury lamp ("EX250" manufactured by HOYA-SCHOTT Corporation) equipped with a short wavelength cut filter (UV: 385 nm) as a light source. After curing, the sample was heated at 100°C for 12 hours to complete the reaction, and a measurement sample was prepared.

[0100] The refractive index of the measurement sample was measured using an Abbe refractometer (manufactured by Kalnew Optical Industries), and the second-order dispersion characteristic (θ g,F) was calculated and evaluated. A value of 0.65 or higher for the secondary dispersion characteristics was evaluated as good. The refractive index of the glass substrate must be higher than that of the cured resin composition. Table 1 shows the evaluation results.

[0101] (3) Transmittance measurement In the same manner as in the measurement of second-order dispersion characteristics, a 500 μm-thick transmittance measurement sample and a 1000 μm-thick transmittance measurement sample were prepared. Note that the refractive index measurement sample prepared for measuring second-order dispersion characteristics may be used as the 500 μm-thick transmittance sample.

[0102] The transmittance of the transmittance measurement samples of each film thickness was measured using a spectrophotometer (Hitachi High-Technologies Corporation, product name "U-4000") and converted into internal transmittance (1000 μm) at a wavelength of 420 nm for evaluation. A transmittance of 90% or higher at a wavelength of 420 nm was evaluated as good. Table 1 shows the evaluation results.

[0103] Examples 2 to 15 and Comparative Examples 1 to 5 A resin composition was prepared in the same manner as in Example 1, except that the exemplary compounds, sulfur-containing compounds, and other resin components listed in Tables 1 and 2 were used. This resin composition was evaluated using the same evaluation methods as in Example 1. The evaluation results are shown in Tables 1 and 2.

[0104] Furthermore, the ratio of carbon atoms to sulfur atoms (carbon atoms / sulfur atoms) was calculated and evaluated by the following method for Examples 3, 4, 5, 7, and 10 and Comparative Example 1. The evaluation results are shown in Table 3.

[0105] (1) XPS measurement In the same way as for measuring the secondary dispersion characteristics, samples with a thickness of 500 μm were prepared, and the quartz glass was then peeled off to prepare the measurement sample. The number of atoms in each sample was measured using an XPS measurement (ULVAC-PHI, Inc., product name "Quantera II"), and the ratio of carbon atoms to sulfur atoms was calculated and evaluated.

[0106] [Table 1]

[0107] [Table 2]

[0108] [Table 3]

[0109] From the results in Tables 1 and 2, all of Examples 1 to 15 had secondary dispersion characteristics of 0.65 or more, and exhibited high transmittance values of 96% or more at 420 nm.

[0110] Examples 1 to 10 had higher transmittance values than Comparative Example 1, which did not contain a sulfur-containing compound. Furthermore, even when the amount of the sulfur-containing compound was increased, i.e., the amount of the exemplary compound exhibiting high secondary dispersion properties was reduced, the secondary dispersion properties remained high. Comparative Example 2, in which the amount of other resin components was increased and the amount of the exemplary compound was reduced compared to Comparative Example 1, exhibited lower secondary dispersion properties than Examples 1 to 10. This is thought to be because, when the amount of other resin components was increased, the amount of cured resins with low secondary dispersion properties increased, resulting in a decrease in secondary dispersion properties and a decrease in transmittance. On the other hand, it is thought that a sulfur-containing compound having a thiol group improves transmittance and maintains secondary dispersion properties.

[0111] Comparative Example 4 is an example in which a sulfur compound is not contained in a resin composition using the exemplary compounds of Examples 11 and 13. Comparative Example 5 is an example in which a sulfur compound is not contained in a resin composition using the exemplary compounds of Examples 14 and 15. All of Examples 11 to 15, like Examples 1 to 10, showed improved transmittance and high secondary dispersion characteristics when a sulfur-containing compound was contained.

[0112] From the results in Table 3, each example exhibited improved transmittance compared to Comparative Example 1 and also exhibited high secondary dispersion characteristics. [Explanation of symbols]

[0113] 1: cured product, 2, 3: transparent substrate, 10: digital camera (imaging device), 11: lens barrel (optical equipment), 13, 15: lens (optical element)

Claims

1. A cured product of a resin composition containing a (meth)acrylate compound and a sulfur-containing compound having at least one thiol group in the molecule, The content of the sulfur-containing compound is 1% by mass or more and 30% by mass or less, The secondary dispersion characteristic of the cured product is 0.65 or more, A cured product characterized in that the (meth)acrylate compound is a compound having an electron-withdrawing group or an electron-donating group bonded to at least two aryl groups, and having three or four benzene rings which may be bonded to each other.

2. 2. The cured product according to claim 1, wherein the (meth)acrylate compound is a compound represented by the following general formula (1): 【Chemical 1】 (In general formula (1), R 1 and R 2 are each independently selected from a substituted or unsubstituted alkyl group having from 1 to 10 carbon atoms, and a substituted or unsubstituted alkylene group having from 1 to 8 carbon atoms and having an acryloyloxy group or a methacryloyloxy group. R 3 ~R 12 are each independently selected from a hydrogen atom, a trifluoromethyl group, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkylene group having an acryloyloxy group or a methacryloyloxy group, an acryloyloxy group or a methacryloyloxy group. However, R 3 ~R 12 At least one of R is a trifluoromethyl group, and 1 ~R 12 At least one of the groups has an acryloyloxy group or a methacryloyloxy group.)

3. The cured product according to claim 1, wherein the (meth)acrylate compound is a compound represented by the following general formula (2): 【Chemistry 2】 (In the general formula (2), X and Y are each S or O. R 21 When X is S, R is an alkyl group having 1 to 2 carbon atoms, and when X is O, R is a hydrogen atom or an alkyl group having 1 to 2 carbon atoms. 22 When Y is S, it is an alkyl group having 1 to 2 carbon atoms, and when Y is O, it is a hydrogen atom or an alkyl group having 1 to 2 carbon atoms. R 23 ~R 30 are each independently selected from a hydrogen atom and a methyl group. a and b are each an integer of 1 or 2; Z 1 and Z 2 are groups represented by the following general formula (3): 1 One of the groups may be a methyl group. When b is 2, Z 2 One of them may be a methyl group.) 【Chemistry 3】 (In general formula (3), * represents a bond. m is selected from 0 and 1. W is a hydrogen atom or a methyl group. V is selected from groups represented by the following general formulas (4) to (6). *-O-C n H 2n -O-** ・・・(4) *-S-C n H 2n -S-** ・・・(5) *-S-C n H 2n -O-** ・・・(6) In the general formulae (4) to (6), * represents a bond to the alkylene group, and ** represents a bond to the (meth)acryloyl group. n is selected from 2, 3, and 4. -C n H 2n At least one hydrogen atom of - may be substituted with a methyl group.

4. The resin composition further contains another resin component, 4. The cured product according to claim 1, wherein the content of the other resin component is 0.01% by mass or more and 20.0% by mass or less.

5. The cured product described in Claim 4, characterized in that the other resin component is a (meth)acrylate compound.

6. 6. The cured product according to claim 1, wherein the content of the sulfur compound is 1% by mass or more and 15% by mass or less.

7. 7. The cured product according to claim 1, wherein the ratio of carbon atoms to sulfur atoms is 15 or more and 130 or less.

8. An optical element comprising a transparent substrate and the cured product according to claim 1 provided on the transparent substrate.

9. An optical element comprising the cured product according to claim 1 sandwiched between two transparent substrates.

10. An optical device having a housing and an optical system having a plurality of lenses disposed within the housing, 10. An optical device, wherein at least one of the plurality of lenses is the optical element according to claim 8.

11. An imaging device having a housing, an optical system having a plurality of lenses arranged in the housing, and an imaging element that receives light that has passed through the optical system, 10. An imaging device, wherein at least one of the plurality of lenses is the optical element according to claim 8.

12. 12. The imaging device according to claim 11, wherein the imaging device is a camera.

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