JP2009271286A - Plastic optical element, and method for manufacturing electronic equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a plastic optical element which is excellent in transparency and maintains its characteristics in a production process including heat treatment and in various use environments, and to provide a method for manufacturing electronic equipment which executes reflow processing using the plastic optical element. <P>SOLUTION: The plastic optical element contains a resin composition having alicyclic hydrocarbon structure and a water-absorption rate of 0.5 mass% or less and has a water-absorption rate of 1.0-2.0 mass% and a size-variation rate of 0.1-0.5% due to water absorption. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a plastic optical element and a method for manufacturing an electronic apparatus.

  Generally, an optical element made of glass or plastic is used as an optical element that transmits light and achieves a desired optical function. Examples of the optical element include an optical lens and a correction element used in various optical devices. For example, an imaging optical system or an optical pickup device used in an imaging apparatus such as a silver salt camera, a digital camera, or a medical imaging apparatus. And optical elements used in optical systems and optical communication modules.

  In particular, plastic optical elements can be easily molded by injection molding or extrusion molding, and can be molded at a relatively low temperature, and can be manufactured at a lower cost than glass optical elements. There is a strong demand for replacement with plastic optical elements.

  Conventionally, an optical element using a thermoplastic resin is widely known as an optical element used in an imaging optical system or an optical system of an optical pickup device. For example, a copolymer of a cyclic olefin and an α olefin has been proposed as a thermoplastic resin applicable to an optical element of an optical pickup device (for example, Patent Document 1). However, optical elements using thermoplastic resins have low heat resistance compared to glass optical elements, and optical characteristics may change when exposed to high temperatures, so high optical accuracy is required. When used as an optical element in an imaging optical system or an optical system of an optical pickup device, reliability of element physical properties may be a problem.

  For example, when an IC (Integrated Circuits) chip or other electronic component is mounted on a circuit board, a paste of a conductive material is previously applied (potted) to a predetermined position on the circuit board, and the electronic component is mounted on the position. A technique for mounting electronic components on the circuit board by reflowing (heating) the circuit board in a placed state and melting a paste of a conductive material is known. When a module is manufactured, an imaging module can be manufactured at low cost by performing a reflow process in a state where an optical element is also mounted on the electronic module on which such an electronic component is mounted. The temperature in such a reflow process is a temperature at which the conductive material paste can be melted, and is usually performed at a temperature of about 180 to 270 ° C. Therefore, when applying a plastic optical element to this reflow process, Therefore, high heat resistance is required without any change in the physical properties of the element at the processing temperature.

On the other hand, in recent years, an organic-inorganic composite material in which inorganic fine particles are dispersed in heat or active energy ray-curable resin has been proposed as an optical material in which the heat resistance of the resin is improved (for example, Patent Document 2). ~ 4). However, even in these disclosed materials, when a relatively high temperature manufacturing application such as a reflow process is applied, the element is deformed or cracked due to the heat treatment, and it is difficult to sufficiently secure transparency as an optical element. there were. Therefore, the actual situation is that a plastic optical element material satisfying high temperature durability while ensuring transparency as an optical element has not yet been obtained.
JP 2002-105131 A JP-A-4-254406 JP-A-8-157735 JP 2005-146042 A

  A resin composition obtained by curing a transparent curable compound having a polymerization reactive group such as a (meth) acryl group is used as an optical element material used in an optical system of a spectacle lens or various optical devices. In recent years, problems such as insufficient heat resistance and a large coefficient of linear expansion are required to ensure the reliability of advanced physical properties against environmental fluctuations required for optical elements used in various optical instruments. there were. In addition, an imaging module can be manufactured at low cost by performing a reflow process in a state where an optical element is also mounted on an electronic device on which an electronic component is mounted, but when applying a plastic optical element to such a reflow process, Is required to have high heat resistance with no variation in the physical properties of the device at the processing temperature. Conventionally, as a means for improving the heat resistance of a resin applied to a plastic optical element and reducing the linear expansion coefficient, a technique for dispersing inorganic fine particles in an organic resin has been disclosed. An optical element made of such a resin is disclosed. Is used in the reflow process, there is a problem that the element is deformed after the heat treatment or the transparency is impaired due to the occurrence of cracks inside the element. The cause is presumed to be due to the deformation caused by the stress due to the rapid absorption of moisture absorbed by the absorption of the resin, resulting in rapid vaporization and expansion.

  An object of the present invention is a plastic optical element (hereinafter simply referred to as an optical element) that is excellent in transparency and can maintain its characteristics in a manufacturing process involving high-temperature processing and various usage environments, and uses the same. An object of the present invention is to provide an electronic device manufacturing method for performing reflow processing.

  As a result of studying the material prescription design based on the resin structure and the water absorption rate, the water absorption rate of the inorganic fine particles contained in the resin composition containing the inorganic fine particles, the specific structure and the water absorption rate in the specific range are obtained. A plastic optical element comprising a resin composition containing a resin having an alicyclic hydrocarbon skeleton and at least one kind of inorganic fine particles having a water absorption rate (water absorption capacity) in a specific range is applied to manufacture of an electronic device having a reflow process step. It has been found that the transparency of the element can be secured without causing deformation or cracks due to heating even in the case of the above. Moreover, in addition to the resin having the alicyclic hydrocarbon skeleton and the inorganic fine particles, a polyfunctional compound is added as necessary to control the cross-linked structure, so that the durability of the element such as heat resistance in various usage environments can be obtained. It has been found that the property can be improved.

  The above object of the present invention is achieved by the following configurations.

  1. It contains a resin composition having an alicyclic hydrocarbon skeleton and a water absorption of 0.5% by mass or less, a water absorption of 1.0 to 2.0% by mass, and a dimensional change rate of 0.1 to 0.1% by water absorption. A plastic optical element characterized by being 0.5%.

  2. 2. The plastic optical element as described in 1 above, wherein the resin composition contains inorganic fine particles having a water absorption rate of 1.0 to 3.0% by mass.

  3. 3. The plastic optical element as described in 2 above, wherein the inorganic fine particles are a semiconductor crystal composition, an inorganic oxide, or a mixture of a semiconductor crystal composition and an inorganic oxide.

  4). The resin composition is obtained by curing a composition of one or more polymerizable monomers selected from alicyclic hydrocarbon compounds represented by the following general formulas (1) to (3). The plastic optical element according to any one of 1 to 3 above.

(In the general formula (1), X is a group represented by —CH ₂ —O—CO—CHR ₁ ═CH ₂ , and R ₁ represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms. )

(In the general formula (2), Y is represented by —O—CO—CHR ₁ ═CH ₂ , or —CO—R ₂ —CHR ₁ ═CH ₂ , or —O—R ₂ —CHR ₁ ═CH _2. R ₁ represents a hydrogen atom or a methyl group, R ₂ represents a single bond, a substituted or unsubstituted alkylene group having 1 to 10 carbon atoms, and R ₃ and R ₄ are each independently A hydrogen atom and a C1-C10 hydrocarbon group are represented, and m represents an integer of 1-3.)

(In the general formula (3), Z is a group represented by _{-O-CO-CHR 1 = CH} 2 or -CHR ₁ = CH _2,, A is a single bond or a carbon - carbon double bonds R ₁ represents a hydrogen atom or a methyl group, and R _{5 to} R ₇ each independently represent a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms.)
5. 5. The plastic optical element as described in any one of 1 to 4 above, which is used in an imaging device that is mounted on a substrate together with an electronic component by reflow processing.

  6). The step of placing the imaging device having the plastic optical element according to any one of 1 to 5 on a substrate together with an electronic component, and subjecting the imaging device, the electronic component, and the substrate to a reflow process, A method for manufacturing an electronic device, comprising: mounting the imaging device and the electronic component on the substrate.

  ADVANTAGE OF THE INVENTION According to this invention, it is excellent in transparency and can manufacture the plastic optical element which can maintain the characteristic in the manufacturing process with high temperature processing, and various use environment, and the manufacture of the electronic device which performs reflow processing using the same It is to provide a method.

  The best mode for carrying out the present invention will be described in detail below, but the present invention is not limited thereto.

  The plastic optical element in the present invention contains a resin composition having an alicyclic hydrocarbon structure and a water absorption of 0.5% by mass or less, a water absorption of 1.0 to 2.0% by mass, and dimensions. The change rate is 0.1 to 0.5%.

  Hereinafter, the present invention will be described in more detail.

<Resin composition>
The resin composition used in the present invention is obtained by polymerizing and curing a polymerizable monomer having an alicyclic hydrocarbon skeleton, and a particularly preferable compound is represented by the general formula (1). Compounds such as tricyclodecane dimethanol dimethacrylate, tricyclodecane dimethanol diacrylate, compounds represented by the general formula (2) such as adamantyl methacrylate, adamantyl acrylate, etc., and the general formula (3) Examples of the compound represented include isobornyl methacrylate, isobornyl acrylate, and vinyl norbornene. These alicyclic hydrocarbon-based compounds may be used alone or in combination of two or more when the polymerization curable composition is formulated. In the process, in order to suppress the deformation and cracking of the element due to heating, it is necessary to control the water absorption rate of the transparent resin constituting the resin composition within a certain range. Here, the water absorption rate of the resin composition is the mass immediately after drying the resin composition obtained by curing the alicyclic hydrocarbon monomer composition at 85 ° C. for 168 hours in a dry oven. (The obtained value is A.) Then, the dried resin composition was stored in a thermo-hygrostat at 60 ° C. and 90% relative humidity for 168 hours. (The obtained value is defined as B), and defined as a value calculated from the obtained measurement result by the following mathematical formula.

Water absorption (mass%) = ((B−A) / A) × 100
The water absorption of the resin composition used in the present invention is preferably 0.5% by mass or less, and more preferably 0.3% by mass or less. When the water absorption rate exceeds 0.5% by mass, the stress at the time of heating based on the water absorption of the resin component constituting the element cannot be relaxed, and the element is deformed or cracked, which is not suitable as an optical element.

<Inorganic fine particles>
Examples of the inorganic fine particles used in the present invention include inorganic oxide fine particles. Specifically, for example, titanium oxide, zinc oxide, aluminum oxide, zirconium oxide, hafnium oxide, niobium oxide, tantalum oxide, magnesium oxide, oxide Calcium, strontium oxide, barium oxide, yttrium oxide, lanthanum oxide, cerium oxide, indium oxide, tin oxide, lead oxide, complex oxides composed of these oxides such as lithium niobate, potassium niobate, lithium tantalate, etc. And phosphates and sulfates formed in combination with these oxides.

  Since these inorganic fine particles exist in a state dispersed in a transparent resin, the average particle diameter is preferably 1 nm or more and 50 nm or less in order to ensure transparency. More preferably, it is 1 nm or more and 30 nm or less, or 1 nm or more and 20 nm or less, and most preferably 1 nm or more and 10 nm or less. When the average particle diameter is 1 nm or more and 50 nm or less, the dispersibility of the inorganic fine particles at the time of production is good, the resulting plastic optical element material has good transparency, and the light transmittance is preferably 70% or more. The average particle diameter here refers to the diameter when converted to a sphere having the same volume as the particles.

  The shape of the inorganic fine particles is not particularly limited, but spherical fine particles are preferably used. Further, the particle size distribution is not particularly limited, but those having a relatively narrow distribution than those having a wide distribution are preferably used.

  In addition, when the plastic optical element containing the inorganic fine particles of the present invention is applied to a manufacturing process having a heat treatment such as a reflow process, the water absorption rate of the inorganic fine particles is constant in order to suppress the deformation of the element and the generation of cracks due to heating. Need to be controlled within range. Here, the water absorption rate of the inorganic fine particles is obtained by measuring the mass immediately after drying the obtained inorganic fine particles in a dry oven at 85 ° C. for 168 hours (the obtained value is A). The dried resin composition was stored in a thermo-hygrostat at a temperature of 60 ° C. and a relative humidity of 90% for 168 hours to measure the mass (the obtained value is B). It is defined as a value calculated by the following mathematical formula from the measured results.

Water absorption (mass%) = ((B−A) / A) × 100
The inorganic fine particles used in the present invention preferably have a water absorption rate of 1.0 to 3.0% by mass, more preferably 1.2 to 2.0% by mass. If the water absorption is less than 1.0% by mass, the stress during heating based on the water absorption of the resin component cannot be relieved, and the element is deformed or cracked. If it exceeds 3.0% by mass, the environment of the element itself Since the variation of the optical characteristics with respect to the variation becomes large, it is not suitable as an optical element.

  These inorganic fine particles may be used in combination of not only one type but also a plurality of types in the resin composition.

<Polyfunctional compound>
The polyfunctional compound used in the present invention is a compound having two or more reactive groups such as a vinyl group, a (meth) acryloyl group, an epoxy group, an oxetanyl group, a mercapto group, and the alicyclic hydrocarbon. It reacts with a system compound to form a crosslinked structure in the resin.

  For example, diethylene glycol dimethacrylate, ethylene glycol dimethacrylate, tetraethylene glycol diacrylate, diethylene glycol diacrylate, trimethylolpropane triacrylate, trimethylolpropane triacrylate having two or more (meth) acryloyl groups as polyfunctional (meth) acrylate Methacrylate, pentaerythritol tetraacrylate, pentaerythritol tetramethacrylate and the like are polyfunctional epoxy compounds, glycidyl ether type epoxy resins such as bisphenol A diglycidyl ether, bisphenol F diglycidyl ether, resorcinol diglycidyl ether, diglycidyl phthalate, and Dimer acid diglycidyl ester, triglycidyl ether trif Nylmethane, tetraglycidyl ether tetraphenyl ethane, bisphenol S diglycidyl ether, cresol novolac glycidyl ether, triglycidyl isocyanurate, tetrabromobisphenol A diglycidyl ether, etc., as polyfunctional oxetane compounds, reaction of polyfunctional phenolic compounds with oxetane chloride Products, for example, bifunctional oxetane compounds such as bisphenol A type, bisphenol F type, bisphenol S type, biphenyl type and cardo type, trifunctional oxetane compounds such as trisphenol methane type and triskresol methane type, phenol novolac type, cresol Examples thereof include polyfunctional oxetane compounds such as novolak type and calixarene type.

  These polyfunctional compounds may be used not only in the resin composition but also in combination of two or more.

<Stabilizer>
In the resin composition of the present invention, one or more stabilizers selected from hindered amine stabilizers, phenol stabilizers, phosphorus stabilizers, and sulfur stabilizers may be additionally added. By suitably selecting these stabilizers and adding them to the resin composition, it is possible to more highly suppress optical property fluctuations such as coloring and refractive index fluctuations caused by resin degradation due to light or heating.

  As a preferable phenol-based stabilizer, conventionally known ones can be used, for example, 2-t-butyl-6- (3-t-butyl-2-hydroxy-5-methylbenzyl) -4-methylphenyl acrylate, 2 , 4-di-t-amyl-6- (1- (3,5-di-t-amyl-2-hydroxyphenyl) ethyl) phenyl acrylate and the like, and JP-A Nos. 63-179953 and 1-168643. Acrylate compounds described in Japanese Patent Publication No. 1; octadecyl-3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate, 2,2′-methylenebis (4-methyl-6-tert-butylphenol), 1,1,3-tris (2-methyl-4-hydroxy-5-tert-butylphenyl) butane, 1,3,5-trimethyl-2,4,6-tris (3,5 Di-t-butyl-4-hydroxybenzyl) benzene, tetrakis (methylene-3- (3 ′, 5′-di-t-butyl-4′-hydroxyphenylpropionate)) methane [ie pentaerythrmethyl- Tetrakis (3- (3,5-di-t-butyl-4-hydroxyphenylpropionate))], triethylene glycol bis (3- (3-t-butyl-4-hydroxy-5-methylphenyl) propionate) Alkyl-substituted phenolic compounds such as 6- (4-hydroxy-3,5-di-t-butylanilino) -2,4-bisoctylthio-1,3,5-triazine, 4-bisoctylthio-1, 3,5-triazine, 2-octylthio-4,6-bis (3,5-di-t-butyl-4-oxyanilino) -1,3,5-triazine, etc. And triazine group-containing phenolic compounds.

  Preferred hindered amine stabilizers include bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate, bis (2,2,6,6-tetramethyl-4-piperidyl) succinate, bis ( 1,2,2,6,6-pentamethyl-4-piperidyl) sebacate, bis (N-octoxy-2,2,6,6-tetramethyl-4-piperidyl) sebacate, bis (N-benzyloxy-2, 2,6,6-tetramethyl-4-piperidyl) sebacate, bis (N-cyclohexyloxy-2,2,6,6-tetramethyl-4-piperidyl) sebacate, bis (1,2,2,6,6) -Pentamethyl-4-piperidyl) 2- (3,5-di-t-butyl-4-hydroxybenzyl) -2-butylmalonate, bis (1-acryloyl-2,2,6 6-tetramethyl-4-piperidyl) 2,2-bis (3,5-di-t-butyl-4-hydroxybenzyl) -2-butylmalonate, bis (1,2,2,6,6-pentamethyl) -4-piperidyldecanedioate, 2,2,6,6-tetramethyl-4-piperidylmethacrylate), 4- [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionyloxy]- 1- [2- (3- (3,5-di-t-butyl-4-hydroxyphenyl) propionyloxy) ethyl] -2,2,6,6-tetramethylpiperidine, 2-methyl-2- (2 , 2,6,6-tetramethyl-4-piperidyl) amino-N- (2,2,6,6-tetramethyl-4-piperidyl) propionamide and the like.

  Further, the preferable phosphorus stabilizer is not particularly limited as long as it is usually used in the general resin industry. For example, triphenyl phosphite, diphenylisodecyl phosphite, phenyl diisodecyl phosphite, tris (nonyl) Phenyl) phosphite, tris (dinonylphenyl) phosphite, tris (2,4-di-t-butylphenyl) phosphite, 10- (3,5-di-t-butyl-4-hydroxybenzyl) -9 Monophosphite compounds such as 1,4-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide; 4,4'-butylidenebis (3-methyl-6-tert-butylphenyl-di-tridecyl phosphite ), 4,4'-isopropylidenebis (phenyl-di-alkyl (C12-C15) phosphine) Ito) diphosphite compounds such as and the like. Among these, monophosphite compounds are preferable, and tris (nonylphenyl) phosphite, tris (dinonylphenyl) phosphite, tris (2,4-di-t-butylphenyl) phosphite and the like are particularly preferable.

  Further, preferable sulfur stabilizers include, for example, dilauryl 3,3-thiodipropionate, dimyristyl 3,3′-thiodipropionate, distearyl 3,3-thiodipropionate, lauryl stearyl 3,3- Thiodipropionate, pentaerythritol-tetrakis (β-laurylthio-propionate), 3,9-bis (2-dodecylthioethyl) -2,4,8,10-tetraoxaspiro [5,5] undecane, etc. It is done.

  Although the compounding quantity of these stabilizers is suitably selected in the range which does not impair the objective of this invention, it is 0.01-2 mass parts normally with respect to 100 mass parts of resin compositions, Preferably it is 0.01-1 mass. Part.

<Plastic optical element>
The resin composition used in the present invention can be cured by either ultraviolet or electron beam irradiation or heat treatment. The alicyclic hydrocarbon-based monomer and inorganic fine particles are mixed and further required. Accordingly, it is obtained by preparing a resin composition to which additives such as a polyfunctional compound and a stabilizer are added and then curing the resin composition. The addition amount of the transparent resin is preferably 10 to 90 parts by mass, more preferably 20 to 70 parts by mass with respect to 100 parts by mass of the resin composition. The addition amount of the inorganic fine particles is preferably 5 to 70 parts by mass, more preferably 10 to 50 parts by mass with respect to 100 parts by mass of the resin composition. The addition amount of the polyfunctional compound is preferably 5 to 80 parts by mass and more preferably 10 to 60 parts by mass with respect to 100 parts by mass of the resin composition.

  In preparing the resin composition before curing, an appropriate method can be employed. For example, when the prepared resin composition is in a liquid state, the components are dissolved after blending a predetermined amount of each component. Mix or mix uniformly with a mixer, blender, etc., and then knead with a kneader or roll to obtain a liquid curable resin composition, and the prepared resin composition is solid. In the case where the components are mixed in a predetermined amount, the components are dissolved and mixed, or mixed uniformly with a mixer, blender, etc. and then heat-kneaded with a kneader, roll, etc., cooled and solidified, and then pulverized to obtain a solid resin composition You can get things.

  As a method of curing the resin composition, when the resin composition is ultraviolet and electron beam curable, a resin composition in which a photopolymerization initiator is added to a light-transmitting mold having a predetermined shape as necessary. After filling or coating on the substrate, it may be cured by irradiation with ultraviolet rays and electron beams.

  Examples of the photopolymerization initiator used here include acetophenone, acetophenone benzyl ketal, 1-hydroxycyclohexyl phenyl ketone, 2,2-dimethoxy-2-phenylacetophenone, xanthone, fluorenone, benzaldehyde, fluorene, anthraquinone, tri Phenylamine, carbazole, 3-methylacetophenone, 4-chlorobenzophenone, 4,4'-dimethoxybenzophenone, 4,4'-diaminobenzophenone, Michler's ketone, benzoinpropyl ether, benzoin ethyl ether, benzyldimethyl ketal, 1- (4- Photoradical initiation such as isopropylphenyl) -2-hydroxy-2-methylpropan-1-one, 2-hydroxy-2-methyl-1-phenylpropan-1-one Etc. The.

  On the other hand, if the resin composition is thermosetting, after preparing a resin composition to which a thermal polymerization initiator such as a thermal radical generator is added, if necessary, thermosetting molding by compression molding, transfer molding, injection molding, etc. can do. Examples of the thermal polymerization initiator used here include 2,2′-azobisisobutyronitrile, 2,2′-azobis (2,4-dimethylvaleronitrile), 2,2′-azobis (4- Azo compounds such as methoxy-2,4-dimethylvaleronitrile), organic peroxides such as benzoyl peroxide, lauroyl peroxide, t-butylperoxypivalate, 1,1′-bis (t-butylperoxy) cyclohexane, etc. It is done.

  When the plastic optical element of the present invention is applied to a manufacturing process having a heat treatment such as a reflow process, the water absorption rate and the dimensional change rate of the optical element are controlled within a certain range in order to suppress deformation and cracking due to heating. Need to be done. Here, the water absorption rate of the optical element means that the element obtained by curing an uncured resin composition was measured in a dry oven immediately after drying at 85 ° C. for 168 hours (obtained). The value is A.) Next, the dried resin composition was measured for mass after being stored in a constant temperature and humidity chamber at 60 ° C. and a relative humidity of 90% for 168 hours (obtained value). Is defined as a value calculated from the obtained mass measurement result by the following mathematical formula.

Water absorption (mass%) = ((B−A) / A) × 100
Further, the dimensional change rate of the optical element refers to an element obtained by curing an uncured resin composition in a mold having a size of 30 mm × 30 mm × 3 mm thickness, After measuring the thickness of the element immediately after drying at 168 ° C. for 168 hours using a micrometer (the obtained value is A), the dried element is then placed in a thermo-hygrostat at 60 ° C. The thickness after storage for 168 hours under the conditions of ° C. and relative humidity of 90% is measured again (the obtained value is B), and is defined as the value calculated by the following formula from the obtained measurement result. .

Dimensional change rate (%) = ((B−A) / A) × 100
The water absorption of the optical element of the present invention is preferably 1.0 to 2.0% by mass, more preferably 1.2 to 1.8% by mass. The dimensional change rate due to water absorption of the element is preferably from 0.1 to 0.5%, more preferably from 0.2 to 0.4%. When the water absorption rate of the element is smaller than 1.0% by mass, or when the dimensional change rate of the element due to water absorption is less than 0.1%, the stress relaxation based on the vaporization and expansion of moisture due to moisture absorption of the element becomes insufficient, The generation of cracks cannot be suppressed. On the other hand, when the water absorption rate of the element exceeds 2.0% by mass, or when the dimensional change rate of the element due to water absorption exceeds 0.5%, the variation of the optical characteristics with respect to the environmental variation of the element itself increases. Not suitable as.

<Imaging device>
As shown in FIG. 1, the imaging apparatus 100 according to the present embodiment includes a circuit board 1 on which electronic components constituting an electronic circuit of a mobile information terminal device such as a mobile phone are mounted. A camera module 2 is mounted. The camera module 2 is a small board mounting camera in which a CCD image sensor and a lens are combined. In a completed state in which the circuit board 1 on which electronic components are mounted is incorporated in the cover case 3, the imaging provided in the cover case 3 is performed. The image to be imaged can be captured through the opening 4 for use. In FIG. 1, illustration of electronic components other than the camera module 2 is omitted.

  As shown in FIG. 2, the camera module 2 is composed of a board module 5 (see FIG. 3A) and a lens module 6 (see FIG. 3C). By mounting the board module 5 on the circuit board 1, The entire camera module 2 is mounted on the circuit board 1. The substrate module 5 is a light receiving module in which a CCD image sensor 11, which is a light receiving element for imaging, is mounted on a sub-substrate 10. The upper surface of the CCD image sensor 11 is sealed with a sealing resin 12.

  On the upper surface of the CCD image sensor 11, a light receiving portion (not shown) in which a large number of pixels that perform photoelectric conversion are arranged in a grid pattern is formed, and an optical image is formed on the light receiving portion to store each pixel. The charged charges are output as an image signal. The sub board 10 is mounted on the circuit board 1 by lead-free solder 18, whereby the sub board 10 is fixed to the circuit board 1, and connection electrodes (not shown) of the sub board 10 and circuits on the upper surface of the circuit board 1 are provided. An electrode (not shown) is electrically connected.

  The lens module 6 includes a lens case 15 that supports the lens 16. A lens 16 is held at the upper part of the lens case 15, and the upper part of the lens case 15 is a holder portion 15 a for holding the lens 16. A lower portion of the lens case 15 is inserted into a mounting hole 10 a provided in the sub-board 10 and serves as a mounting portion 15 b that fixes the lens module 6 to the sub-board 10. For this fixing, a method of pressing and fixing the mounting portion 15b into the mounting hole 10a, a method of bonding with an adhesive, or the like is used.

  The lens 16 is for imaging the reflected light from the subject on the light receiving portion of the CCD image sensor 11.

<Imaging apparatus and method for manufacturing electronic device>
A method for manufacturing the imaging device 100 according to the present embodiment will be described with reference to FIG.

  First, the substrate module 5 and the lens module 6 are assembled. As shown in FIG. 3A, the lens case until the lower end portion of the collar member 17 mounted in advance in the lens case 15 comes into contact with the upper surface of the sub-substrate 10. The 15 mounting portions 15b are inserted and fixed in the mounting holes 10a of the sub-board 10 to form the camera module 2.

  Thereafter, as shown in FIG. 3B, the camera module 2 and other electronic components are placed at a predetermined mounting position of the circuit board 1 to which the solder 18 has been applied (potted) in advance. Thereafter, as shown in FIG. 3C, the circuit board 1 on which the camera module 2 and other electronic components are placed is transferred to a reflow furnace (not shown) by a belt conveyor or the like, and the circuit board 1 is subjected to reflow processing. And heat at a temperature of about 260 ° C. As a result, the solder 18 is melted and the camera module 2 is mounted on the circuit board 1 together with other electronic components.

  EXAMPLES Next, although an Example demonstrates this invention concretely, this invention is not limited to these.

(Production Example 1)
50 parts by mass of pure water, 390 parts by mass of special grade ethanol (manufactured by Kanto Chemical), 28% ammonia (manufactured by Kanto Chemical) 22 with respect to 7.2 parts by mass of alumina (Alumina C, Nippon Aerosil Co., Ltd., primary particle size 13 nm) A solution to which parts by mass were added was prepared, 0.72 parts by mass of tetraethoxysilane (LS-2430, manufactured by Shin-Etsu Chemical Co., Ltd.) was added to the solution, and then the solution was ultra-apex mill UAM-015 (manufactured by Kotobuki Industries Co., Ltd.). ) And dispersed for 1 hour at a peripheral speed of 6 m / sec using 0.05 mm beads. Thereafter, 0.72 parts by mass of tetraethoxysilane (LS-2430 manufactured by Shin-Etsu Chemical Co., Ltd.) was further added to the dispersion, followed by stirring for 1 hour.

  Next, 18.2 parts by mass of tetraethoxysilane (LS-2430 manufactured by Shin-Etsu Chemical Co., Ltd.) is diluted with a mixed solution of 40 parts by mass of ethanol and 5 parts by mass of pure water, and the diluted solution is added to the above dispersion for 10 minutes. After the dropwise addition, the solution was stirred at room temperature for 20 hours to form a silica layer on the alumina surface.

  Next, inorganic fine particles were separated from the solution using a centrifuge and dried under reduced pressure at 80 ° C. for 24 hours. The dried inorganic fine particles were put into an eggplant flask, depressurized to 1.3 kPa or less, and heated at 190 ° C. for 1 hour, and then the inside of the eggplant flask was replaced with argon. ) Was added to the inorganic fine particles in an amount of 300 parts by mass, and stirred well at 300 ° C. to obtain inorganic fine particles A. The water absorption rate of the inorganic fine particles A was measured and found to be 0.4% by mass. The water absorption is measured in accordance with the above method by measuring the mass immediately after storage of inorganic fine particles in a dry oven; DS400 (manufactured by Yamato Scientific Co., Ltd.) at 85 ° C. for 168 hours, followed by a constant temperature and humidity chamber; IH400 (Yamato Scientific) The mass after storage for 168 hours at 60 ° C. and 90% relative humidity was measured and calculated.

(Production Example 2)
In Production Example 1, inorganic fine particles B were obtained in the same manner except that 200 parts by mass of hexamethyldisilazane was added to the inorganic fine particles. As a result of measuring the water absorption of the inorganic fine particles B, it was 0.6% by mass.

(Production Example 3)
In Production Example 1, inorganic fine particles C were obtained in the same manner except that 150 parts by mass of hexamethyldisilazane was added to the inorganic fine particles. As a result of measuring the water absorption of the inorganic fine particles C, it was 1.5% by mass.
(Production Example 4)
In Production Example 1, inorganic fine particles D were obtained in the same manner except that 100 parts by mass of hexamethyldisilazane was added to the inorganic fine particles. As a result of measuring the water absorption of the inorganic fine particles D, it was 2.8% by mass.
(Production Example 5)
In Production Example 1, inorganic fine particles E were obtained by the same operation except that 70 parts by mass of hexamethyldisilazane was added to the inorganic fine particles. As a result of measuring the water absorption of the inorganic fine particles E, it was 3.2% by mass.

(Production Example 6)
By the method disclosed in JP-A-2006-36732, 1-adamantanol and methacrylic acid were reacted to obtain adamantyl methacrylate.

(Production Example 7)
According to the composition shown in Table 1, the raw materials were mixed to obtain thermosetting transparent resin compositions A to D. The obtained resin composition was filled in a mold having dimensions of 30 mm × 30 mm × 3 mm, respectively, and then heated and pressed under the conditions of 120 ° C. and 10 Torr to obtain a plate-like transparent resin molded body. The results of measuring the water absorption rate of the obtained resin molded body are shown together in Table 1. According to the above method, the water absorption is measured by measuring each mass of the transparent resin molding in a dry oven; DS400 (manufactured by Yamato Scientific Co., Ltd.) immediately after being stored at 85 ° C. for 168 hours, and then a constant temperature and humidity chamber; IH400 (Yamato) (Manufactured by Kagakusha), the mass after storage for 168 hours at 60 ° C. and 90% relative humidity was measured and calculated.

<Production of Plastic Optical Elements of Examples 1 to 5 and Comparative Examples 1 to 7>
According to the composition shown in Table 2, after mixing each raw material, it knead | mixed using the kneader and obtained the uniform thermosetting resin composition. Each of the obtained resin compositions was filled in a mold having dimensions of 30 mm × 30 mm × 3 mm, and then heated and pressed at 120 ° C. and 10 Torr to obtain a plate-like plastic optical element.

  In Tables 1 and 2, details of each component other than the inorganic fine particles are as follows.

Alicyclic hydrocarbon compound A: Tricyclodecane dimethanol dimethacrylate Alicyclic hydrocarbon compound B: Adamantyl methacrylate Alicyclic hydrocarbon compound C: Isoboronyl methacrylate Polyfunctional compound A: Pentaerythritol tetraacrylate Multifunctional compound B: Trimethylolpropane trimethacrylate Stabilizer A: Tetrakis (1,2,2,6,6-pentamethylpiperidyl) butanetetracarboxylate Stabilizer B: 2,2'-methylenebis (4,6- Di-t-butylphenyl) -2-ethylhexyl phosphite Polymerization initiator: Azobisisobutyronitrile Next, the plastic optical elements obtained in Examples 1 to 5 and Comparative Examples 1 to 7 are described below. The physical properties were evaluated based on the method and the results are shown in Table 2.

[Evaluation of plastic optical elements]
(Measurement of water absorption)
For each sample, according to the method described above, the mass of the element immediately after being stored at 85 ° C. for 168 hours in a dry oven; DS400 (manufactured by Yamato Kagaku) is measured, and then a constant temperature and humidity chamber; IH400 (manufactured by Yamato Kagaku) The water absorption rate of the device was calculated by measuring the mass after storage for 168 hours in an environment of 60 ° C. and 90% humidity.

(Measurement of dimensional change rate)
For each sample, according to the above method, the thickness of the element immediately after being stored at 85 ° C. for 168 hours in a dry oven; DS400 (manufactured by Yamato Scientific Co., Ltd.) was measured using a micrometer; ABSOLUTE 156-101 (manufactured by Mitutoyo Corporation). Next, in a constant temperature and humidity chamber; IH400 (manufactured by Yamato Kagaku Co., Ltd.), the thickness after storage for 168 hours in an environment of 60 ° C. and 90% relative humidity was measured, and the dimensional change rate of the element was calculated. .

(Evaluation of high temperature durability)
Evaluation of the high temperature durability of the plastic optical element was performed by subjecting each molded body to reflow treatment, and measuring the light transmittance at 450 nm before and after the reflow treatment, and the change in surface shape. The reflow treatment was performed using a high-temperature observation furnace; SMT Scope SA-5000 (manufactured by SANYO SEIKO), and the conditions were as shown in FIG. 4 (upper solid line portion). Specifically, in FIG. 4, the “average ramp-up speed (speed from Tsmax to Tp)” is set to 3 ° C./s maximum, the “preheat minimum temperature (Tsmin)” is set to 150 ° C., and the “preheat maximum temperature (Tsmax)” ”Is 200 ° C.,“ Preheat time (time from tsmin to tsmax) ”is 60 to 180 seconds,“ Maintenance temperature (TL) ”is 217 ° C., and“ Maintenance time (tL) ”is 60 to 150 seconds. , “Peak temperature (Tp)” is set to 260 ° C., “Peak time (tp)” is set to 20 to 40 seconds, “Ramp down rate” is set to 6 ° C./second, and “Time from 25 ° C. to peak temperature” The maximum was 8 minutes.

  The light transmittance was measured in accordance with ASTM D1003, and the transmittance at a thickness of 3 mm was measured using TURBIDITY METER T-2600DA (manufactured by Tokyo Denshoku Co., Ltd.). The surface shape change was measured with a three-dimensional measuring machine (UA3P, manufactured by Matsushita Electric Industrial Co., Ltd.). Evaluation is performed on the elements before and after the reflow treatment by a method defined in JISB0601, and a reference length of 2 mm is extracted in the direction of the average line of the roughness curve at 10 points of each element, and is highest from the average line of the extracted portion. Height to mountain; Yp and lowest valley; Sum of Yv; Ry value was measured to determine its average value, and the amount of change before and after the reflow treatment was determined as the surface shape change, and evaluation was performed. . The results are shown in Table 2.

  In addition, the notation in the table follows the following criteria.

  A: Shape difference (surface shape change) is less than 200 nm.

  A: The shape difference (surface shape change) is 200 or more and less than 500 nm.

  X: Shape difference (surface shape change) is 500 nm or more.

  According to Table 2, it turns out that the molded object shape | molded using the resin composition which concerns on this invention has high temperature durability which can endure reflow processing, while ensuring transparency.

It is a schematic perspective view of the imaging device used by preferable embodiment of this invention. 1 is an enlarged schematic cross-sectional view of a part of an imaging apparatus used in a preferred embodiment of the present invention. It is drawing for demonstrating schematically the manufacturing method of the imaging device in preferable embodiment of this invention. It is drawing which shows the outline of the reflow conditions (reflow profile) in the preferable Example of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Imaging device 1 Circuit board 2 Camera module 3 Cover case 4 Imaging opening 5 Board | substrate module 6 Lens module 10 Sub board | substrate 10a Mounting hole 11 CCD image sensor 12 Sealing resin 15 Lens case 15a Holder part 15b Mounting part 16 Lens 17 Color member 18 Solder

Claims (6)

It contains a resin composition having an alicyclic hydrocarbon skeleton and a water absorption of 0.5% by mass or less, a water absorption of 1.0 to 2.0% by mass, and a dimensional change rate of 0.1 to 0.1% by water absorption. A plastic optical element characterized by being 0.5%. The plastic optical element according to claim 1, wherein the resin composition contains inorganic fine particles having a water absorption rate of 1.0 to 3.0 mass%. 3. The plastic optical element according to claim 2, wherein the inorganic fine particles are a semiconductor crystal composition, an inorganic oxide, or a mixture of a semiconductor crystal composition and an inorganic oxide. The resin composition is obtained by curing a composition of one or more polymerizable monomers selected from alicyclic hydrocarbon compounds represented by the following general formulas (1) to (3). The plastic optical element according to any one of claims 1 to 3.

(In the general formula (1), X is a group represented by —CH ₂ —O—CO—CHR ₁ ═CH ₂ , and R ₁ represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms. )

(In the general formula (2), Y is represented by —O—CO—CHR ₁ ═CH ₂ , or —CO—R ₂ —CHR ₁ ═CH ₂ , or —O—R ₂ —CHR ₁ ═CH _2. R ₁ represents a hydrogen atom or a methyl group, R ₂ represents a single bond, a substituted or unsubstituted alkylene group having 1 to 10 carbon atoms, and R ₃ and R ₄ are each independently A hydrogen atom, a hydrocarbon group having 1 to 10 carbon atoms, and m represents an integer of 1 to 3)

(In the general formula (3), Z is a group represented by _{-O-CO-CHR 1 = CH} 2 or -CHR ₁ = CH _2,, A is a single bond or a carbon - carbon double bonds R ₁ represents a hydrogen atom or a methyl group, and R _{5 to} R ₇ each independently represent a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms.) The plastic optical element according to any one of claims 1 to 4, wherein the plastic optical element is used in an imaging device mounted on a substrate by reflow processing together with an electronic component. A step of placing the imaging device having the plastic optical element according to any one of claims 1 to 5 on a substrate together with an electronic component; and the reflow processing of the imaging device, the electronic component, and the substrate. And a step of mounting the imaging device and the electronic component on the substrate.

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