JP2010015095A - Optical element, method of manufacturing optical element and method of manufacturing electronic device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lens used integrally with an image capturing apparatus and an electronic component, the lens having improved heat resistance for a reflow process and preventing a reflection preventing film from cracking and peeling. <P>SOLUTION: An imaging lens 9 includes: a wafer lens 91 serving as a substrate at least one of the optical faces of which is formed from a rein material containing hard resin; and the reflection preventing film 92 formed from an organic material on the optical face of the substrate. The reflection preventing film 92 is formed by substituting the optical face of the substrate with fluorine. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an optical element, a method for manufacturing an optical element, and a method for manufacturing an electronic device.

Conventionally, in the technical field of electronic modules in which an IC (Integrated Circuits) chip or other electronic component is mounted on a circuit board, a metal paste (for example, solder paste) is applied (potted) in advance to a predetermined position on the circuit board. A technology for manufacturing an electronic module at a low cost has been developed by a technique in which the circuit board is subjected to a reflow process (heating process) with the electronic component placed at the position, and the electronic component is mounted on the circuit board. (For example, refer to Patent Document 1). In recent years, a technique using such a technique for an electronic device such as a mobile phone with an imaging device has been studied.
On the other hand, a resin material is preferably used as the material of the optical element used in the imaging apparatus from the viewpoint of easy molding. In general, thermoplastic resins that can be molded by injection molding are widely used as imaging optical elements. However, when performing reflow processing in which an imaging device and electronic components are integrally mounted on a circuit board, there is a problem that the optical element made of resin is softened and cannot be used.

As one of the techniques using reflow processing, an imaging device including an electronic member provided with a socket (lens case) and other electronic components are placed on a circuit board and mounted on the circuit board by reflow processing. A technique for manufacturing an electronic apparatus having an imaging device by fitting an imaging lens in a socket has also been proposed (see, for example, Patent Document 2). However, in such a technique, it is necessary to position the imaging optical system in a state in which the electronic components of the imaging device are mounted on the circuit board, which makes accurate positioning difficult and limits the shape of the optical system. Or the lens is limited to a simple configuration of a fixed focus type, and another solution has been demanded.
Therefore, when manufacturing an imaging apparatus to be subjected to reflow processing, the present inventors have a resin material with high heat resistance, for example, 3 once cured, so that the imaging lens has reflow resistance. The use of a curable resin such as a thermosetting resin or a photocurable resin that forms a three-dimensional network structure and does not exhibit fluidity even at high temperatures is being studied. When a curable resin is used, the heat resistance is higher than that of a thermoplastic resin, and it is possible to suppress deterioration of optical performance due to softening or decomposition due to reflow treatment.

By the way, generally, an imaging lens is provided with an antireflection film made of an inorganic material on a base material from the viewpoint of reducing a light amount loss due to reflection on the surface. Conventionally, when an antireflection film is provided on a base material made of a thermoplastic resin, it is deposited on the base material at 100 ° C. or lower in order to avoid softening of the thermoplastic resin.
However, when an imaging lens having an antireflection film formed on a curable resin base material under the same conditions is subjected to reflow treatment, problems such as softening and coloring of the base material do not occur, but a new It turns out that a problem occurs. When an imaging lens in which an antireflection film made of an inorganic material is formed on a curable resin substrate is subjected to reflow processing, the linear expansion coefficient of the resin of the substrate is large, whereas the line of the antireflection film Since the expansion coefficient is small, only the base material portion expands, resulting in a problem that a crack occurs in the antireflection film.
In response to such a problem, in anticipation of expansion of the base material portion during the reflow process, we also considered depositing an antireflection film on the base material that had been expanded in advance at a high temperature. On the contrary, since the base material portion contracts greatly, the antireflection film may peel off from the base material surface, and the transmittance may be lowered.

On the other hand, in the technical field of a conventional optical element made of a thermoplastic resin, a technique for controlling the refractive index by replacing the surface of a base material with fluorine instead of providing an antireflection film made of an inorganic material has been developed. Furthermore, by providing an organic material layer on the surface side of such a fluorine-substituted layer, further replacing the surface of the organic material layer with fluorine, and laminating these organic material layers and fluorine-substituted layers alternately, A technique for improving the antireflection function has been developed as a structure in which a high refractive index layer and a low refractive index layer are laminated (see, for example, Patent Document 3).
JP 2001-24320 A JP 2004-153855 A JP 2005-274748 A

  However, when the technique described in Patent Document 3 is applied and only the fluorine-substituted layer is provided on the surface of the resin base material, it has been found that sufficient antireflection effect cannot be obtained and the loss of light amount increases. did. Furthermore, when the antireflection effect is enhanced by laminating an organic material layer and a fluorine-substituted layer, when the imaging lens is subjected to a reflow process, the organic material layer is colored by the reflow process, thereby reducing the transmittance. As a result, a new problem of increasing the light loss has occurred.

  An object of the present invention is to provide an optical element, an optical element manufacturing method, and an electronic device manufacturing method capable of improving the heat resistance against reflow treatment and preventing the occurrence of cracks and film peeling in an antireflection film. It is.

According to one aspect of the present invention, an optical element comprising:
A substrate formed of a resin material including at least one optical surface containing a curable resin;
An antireflection film made of an inorganic material formed on the optical surface of the substrate;
The surface of the optical surface of the substrate is substituted with fluorine.

In this optical element,
The substrate is
A first optical member made of a material containing glass or a curable resin;
It is preferable that the wafer lens has a second optical member made of a resin material containing a curable resin and bonded to the surface of the first optical member.

According to another aspect of the present invention, there is provided a method for manufacturing an optical element,
Using a base material formed of a resin material including at least one optical surface containing a curable resin,
After fluorine-substituting the surface of the optical surface of the substrate,
An antireflection film made of an inorganic material is formed on the optical surface of the substrate.

According to another aspect of the present invention, there is provided a method for manufacturing an electronic device,
After placing the optical element as the imaging lens manufactured by the manufacturing method of the optical element of the present invention on the substrate together with the electronic component,
The imaging lens, the electronic component, and the substrate are subjected to reflow processing, and the imaging lens and the electronic component are mounted on the substrate as an imaging module.

  By studying the present invention, the surface of the optical surface of the resin base material is substituted with fluorine to form a fluorine-substituted layer, and an antireflection film made of an inorganic material is formed thereon, whereby cracks in the antireflection film It has been found that occurrence of film peeling can be remarkably suppressed, and heat resistance that can withstand reflow treatment can be imparted by using a base material made of a curable resin. By using such an optical element as an imaging lens, an electronic module can be manufactured at low cost using reflow processing.

  Next, preferred embodiments of the present invention will be described with reference to the drawings.

[First Embodiment]
As shown in FIG. 1, an electronic device 100 is an example of a small electronic device such as a mobile phone with an imaging function, and includes a circuit board 101 on which electronic components are mounted. An imaging module 102 is mounted on the circuit board 101. The imaging module 102 is a small board mounting camera that combines a CCD image sensor and a lens. In a completed state in which the circuit board 101 on which electronic components are mounted is incorporated in the cover case 103, an image to be imaged can be captured through the imaging opening 104 provided in the cover case 103.
In FIG. 1, illustration of electronic components other than the electronic components of the imaging module 102 is omitted.

  As shown in FIG. 2, the imaging module 102 includes a board module 105 (see FIG. 14A) and a lens module 106 (see FIG. 14A). By mounting the board module 105 on the circuit board 101, The entire imaging module 102 is mounted on the circuit board 101. The substrate module 105 is a light receiving module in which a CCD image sensor 110 that detects light collected by the lens module 106 is mounted on a sub-substrate 130. The upper surface of the CCD image sensor 110 is sealed with a resin 120. A CCD image sensor is an example of a sensor device.

  On the upper surface of the CCD image sensor 110, a light receiving portion (not shown) in which a large number of pixels that perform photoelectric conversion are arranged in a grid is formed, and an optical image is formed on the light receiving portion, thereby storing each pixel. The charged charges are output as an image signal. The sub-board 130 is mounted on the circuit board 101 by a conductive material 180 such as solder, whereby the sub-board 130 is fixed to the circuit board 101, and the connection electrodes (not shown) of the sub-board 130 and the upper surface of the circuit board 101 are fixed. The circuit electrode (not shown) is electrically connected.

  The lens module 106 includes a lens case 150. The lens case 150 holds the IR cut filter 160 and the imaging lens 9. The upper part of the lens case 150 is an IR cut filter 160 and a holder portion 150 a that holds the imaging lens 9.

  A lower portion of the lens case 150 is inserted into a mounting hole 130 a provided in the sub-board 130 and serves as a mounting portion 150 b that fixes the lens module 106 to the sub-board 130. For this fixing, a method of pressing and fixing the mounting portion 150b into the mounting hole 130a, a method of bonding with an adhesive, or the like is used.

  In the electronic apparatus 100 described above, when light enters from the imaging aperture 104 (see FIG. 1), the light passes through the imaging lens 9 and is shielded from infrared rays by the IR cut filter 160, and thereafter enters the CCD image sensor 110. Then, photoelectric conversion is performed by the CCD image sensor 110 to generate an image or the like.

Next, the imaging lens 9 will be described in detail.
As shown in FIGS. 2 and 3, the imaging lens 9 includes a wafer lens 91 as a base material in the present invention and antireflection films 92 formed on both front and back surfaces of the wafer lens 91.

  The wafer lens 91 includes a flat plate-like first optical member 911 and second and third optical members 912 and 913 which are bonded to the front and back surfaces of the first optical member 911 to form an optical surface. Yes.

  As shown in FIG. 3, the wafer lens 91 is formed integrally with the other wafer lens 91 as the lens array 1 and then at the time of product shipment or the like, the second and third optical members 912 and 913 are formed. Each is cut / divided into a lattice shape and manufactured as a product (wafer lens 91).

  The lens array 1 includes a rectangular glass substrate 3 that is divided to form a first optical member 911, and a plurality of lens portions 5 that form second and third optical members 912 and 913. The plurality of lens portions 5 are arranged in an array on the glass substrate 3. The lens unit 5 may be formed on the surface of the glass substrate 3 or may be formed on both front and back surfaces. The lens unit 5 may have a fine structure such as a diffraction groove or a step on the surface of the optical surface.

<Lens part>
The lens unit 5 is made of resin 5A. As this resin 5A, a curable resin can be used. The curable resin can be roughly classified into a photocurable resin and a thermosetting resin. As the photocurable resin, an acrylic resin and an allyl resin can be reactively cured by radical polymerization. Any epoxy resin can be cured by cationic polymerization. On the other hand, the thermosetting resin can be cured by addition polymerization such as silicone in addition to the above radical polymerization and cationic polymerization.

Details of each of the above resins will be described below.
(acrylic resin)
The (meth) acrylate used for the polymerization reaction is not particularly limited, and the following (meth) acrylate produced by a general production method can be used. Ester (meth) acrylate, urethane (meth) acrylate, epoxy (meth) acrylate, ether (meth) acrylate, alkyl (meth) acrylate, alkylene (meth) acrylate, (meth) acrylate having an aromatic ring, alicyclic structure The (meth) acrylate which has is mentioned. One or more of these can be used.
In particular, (meth) acrylate having an alicyclic structure is preferable, and may be an alicyclic structure containing an oxygen atom or a nitrogen atom. For example, cyclohexyl (meth) acrylate, cyclopentyl (meth) acrylate, cycloheptyl (meth) acrylate, bicycloheptyl (meth) acrylate, tricyclodecyl (meth) acrylate, tricyclodecane dimethanol (meth) acrylate, isoboronyl (meth) ) Acrylates, di (meth) acrylates of hydrogenated bisphenols, and the like. In particular, it preferably has an adamantane skeleton. For example, 2-alkyl-2-adamantyl (meth) acrylate (see Japanese Patent Application Laid-Open No. 2002-193883), adamantyl di (meth) acrylate (Japanese Patent Application Laid-Open No. 57-5000785), diallyl adamantyl dicarboxylate (Japanese Patent Application Laid-Open No. 60-100537). ), Perfluoroadamantyl acrylate (JP 2004-123687), Shin-Nakamura Chemical 2-methyl-2-adamantyl methacrylate, 1,3-adamantanediol diacrylate, 1,3,5-adamantanetriol triacrylate, Saturated carboxylic acid adamantyl ester (JP 2000-119220), 3,3′-dialkoxycarbonyl-1,1 ′ biadamantane (see JP 2001-253835), 1,1′-biadamantane compound (US Patent) No. 3342880), Tet Curing having an adamantane skeleton having no aromatic ring such as adamantane (see JP-A-2006-169177), 2-alkyl-2-hydroxyadamantane, 2-alkyleneadamantane, di-tert-butyl 1,3-adamantanedicarboxylate Resin (see JP-A-2001-322950), bis (hydroxyphenyl) adamantanes, bis (glycidyloxyphenyl) adamantane (see JP-A-11-35522, JP-A-10-130371) and the like. .
It is also possible to contain other reactive monomers. In the case of (meth) acrylate, for example, methyl acrylate, methyl methacrylate, n-butyl acrylate, n-butyl methacrylate, 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, isobutyl acrylate, isobutyl methacrylate, tert-butyl acrylate Tert-butyl methacrylate, phenyl acrylate, phenyl methacrylate, benzyl acrylate, benzyl methacrylate, cyclohexyl acrylate, cyclohexyl methacrylate, and the like.
Examples of the polyfunctional (meth) acrylate include trimethylolpropane tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol hexa (meth) acrylate, dipentaerythritol penta (meth) ) Acrylate, dipentaerythritol tetra (meth) acrylate, dipentaerythritol tri (meth) acrylate, tripentaerythritol octa (meth) acrylate, tripentaerythritol septa (meth) acrylate, tripentaerythritol hexa (meth) acrylate, tripenta Erythritol penta (meth) acrylate, tripentaerythritol tetra (meth) acrylate, tripentaerythritol (Meth) acrylate.

(Allyl ester resin)
Examples of resins that have an allyl group and are cured by radical polymerization include the following, but are not particularly limited to the following.
Bromine-containing (meth) allyl ester not containing an aromatic ring (see JP 2003-66201 A), allyl (meth) acrylate (see JP 5-286896 A), allyl ester resin (JP 5-286896 A) , JP 2003-66201 A), a copolymer compound of an acrylate ester and an epoxy group-containing unsaturated compound (see JP 2003-128725 A), an acrylate compound (see JP 2003-147072 A), acrylic Examples include ester compounds (see JP 2005-2064 A).

(Epoxy resin)
The epoxy resin is not particularly limited as long as it has an epoxy group and is polymerized and cured by light or heat, and an acid anhydride, a cation generator, or the like can be used as a curing initiator. Epoxy resin is preferable in that it has a low cure shrinkage and can be a lens with excellent molding accuracy.
Examples of the epoxy include novolak phenol type epoxy resin, biphenyl type epoxy resin, and dicyclopentadiene type epoxy resin. Examples include bisphenol F diglycidyl ether, bisphenol A diglycidyl ether, 2,2′-bis (4-glycidyloxycyclohexyl) propane, 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate, vinyl Cyclohexene dioxide, 2- (3,4-epoxycyclohexyl) -5,5-spiro- (3,4-epoxycyclohexane) -1,3-dioxane, bis (3,4-epoxycyclohexyl) adipate, 1,2 -Cyclopropanedicarboxylic acid bisglycidyl ester etc. can be mentioned.
A hardening | curing agent is used when comprising curable resin material, and there is no limitation in particular. Moreover, in this invention, when comparing the transmittance | permeability of the curable resin material and the optical material after adding an additive, a hardening | curing agent shall not be contained in an additive. As the curing agent, an acid anhydride curing agent, a phenol curing agent, or the like can be preferably used. Specific examples of the acid anhydride curing agent include phthalic anhydride, maleic anhydride, trimellitic anhydride, pyromellitic anhydride, hexahydrophthalic anhydride, 3-methyl-hexahydrophthalic anhydride, 4-methyl-hexahydrophthalic anhydride. Examples thereof include an acid, a mixture of 3-methyl-hexahydrophthalic anhydride and 4-methyl-hexahydrophthalic anhydride, tetrahydrophthalic anhydride, nadic anhydride, methyl nadic anhydride and the like. Moreover, a hardening accelerator is contained as needed. The curing accelerator is not particularly limited as long as it has good curability, is not colored, and does not impair the transparency of the thermosetting resin. For example, 2-ethyl-4-methylimidazole Imidazoles such as (2E4MZ), tertiary amines, quaternary ammonium salts, bicyclic amidines such as diazabicycloundecene and their derivatives, phosphines, phosphonium salts, etc. can be used, Two or more kinds may be mixed and used.

(Silicone resin)
A silicone resin having a siloxane bond with Si—O—Si as the main chain can be used. As the silicone resin, a silicone resin made of a predetermined amount of polyorganosiloxane resin can be used (for example, see JP-A-6-9937).
The thermosetting polyorganosiloxane resin is not particularly limited as long as it becomes a three-dimensional network structure with a siloxane bond skeleton by a continuous hydrolysis-dehydration condensation reaction by heating. It exhibits curability and has the property of being hard to be re-softened by overheating once cured.
Such a polyorganosiloxane resin includes the following general formula (A) as a structural unit, and the shape thereof may be any of a chain, a ring, and a network.
((R ₁ ) (R ₂ ) SiO) _n (A)
In the general formula (A), “R ₁ ” and “R ₂ ” represent the same or different substituted or unsubstituted monovalent hydrocarbon groups. Specifically, as “R ₁ ” and “R ₂ ”, an alkyl group such as a methyl group, an ethyl group, a propyl group and a butyl group, an alkenyl group such as a vinyl group and an allyl group, an allyl group such as a phenyl group and a tolyl group Group, a cycloalkyl group such as a cyclohexyl group or a cyclooctyl group, or a group in which a hydrogen atom bonded to a carbon atom of these groups is substituted with a halogen atom, a cyano group, an amino group, or the like, such as a chloromethyl group, 3, 3, Examples include 3-trifluoropropyl group, cyanomethyl group, γ-aminopropyl group, N- (β-aminoethyl) -γ-aminopropyl group, and the like. “R ₁ ” and “R ₂ ” may be a group selected from a hydroxyl group and an alkoxy group. In the general formula (A), “n” represents an integer of 50 or more.
The polyorganosiloxane resin is usually used after being dissolved in a hydrocarbon solvent such as toluene, xylene or petroleum solvent, or a mixture of these with a polar solvent. Moreover, you may mix | blend and use what has a different composition in the range which mutually melt | dissolves.
The method for producing the polyorganosiloxane resin is not particularly limited, and any known method can be used. For example, it can be obtained by hydrolysis or alcoholysis of one or a mixture of two or more organohalogenosilanes. Polyorganosiloxane resins generally contain hydrolyzable groups such as silanol groups or alkoxy groups. A group is contained in an amount of 1 to 10% by weight in terms of a silanol group.
These reactions are generally performed in the presence of a solvent capable of melting the organohalogenosilane. It can also be obtained by a method of synthesizing a block copolymer by cohydrolyzing a linear polyorganosiloxane having a hydroxyl group, an alkoxy group or a halogen atom at the molecular chain terminal with an organotrichlorosilane. The polyorganosiloxane resin thus obtained generally contains the remaining HCl, but in the composition of the present embodiment, the storage stability is good, so that the one having 10 ppm or less, preferably 1 ppm or less is used. Is good.

The surface of the lens array 1 described above, that is, the surface of the lens portion 5 in the present embodiment is substituted with fluorine to form a fluorine-substituted layer 500 as shown in the enlarged view of FIG.
The fluorine-substituted layer 500 is formed by exposing the lens array 1 to fluorine gas by dry processing at normal temperature and normal pressure, and has a thickness of about 5 μm or 1 μm from the surface side, for example. As such a fluorine substitution technique, for example, the technique disclosed in Patent Document 3 can be used.

  The antireflection film 92 is formed on the wafer lens 91 with an inorganic material. In the present embodiment, the antireflection film 92 has a two-layer structure. Specifically, the first layer 61 is formed on the wafer lens 91 via the fluorine substitution layer 500, and the second layer 62 is formed thereon.

The first layer 61 is a layer made of a high refractive index material having a refractive index of 1.7 or more, preferably Ta ₂ O ₅ , a mixture of Ta ₂ O ₅ and TiO ₂ , ZrO ₂ , ZrO ₂ and TiO _2. And is composed of any mixture. The first layer 61 may be composed of TiO ₂ , Nb ₂ O ₃ , and HfO ₂ . The second layer 62 is a layer made of a low refractive index material having a refractive index of less than 1.7, and is preferably made of SiO ₂ .

  In the antireflection film 92, the first layer 61 and the second layer 62 are both formed by a method such as vapor deposition. Specifically, the film formation temperatures of the first layer 61 and the second layer 62 are subjected to a reflow process. It is formed while being kept in the range of −40 to + 40 ° C. (preferably −20 to + 20 ° C.) with respect to the melting temperature of the conductive paste such as solder (this will be further described later).

  In the wafer lens 91, the first layer 61 and the second layer 62 may be alternately stacked on the first layer 61 and the second layer 62, and the antireflection film 92 may have a 2 to 7 layer structure as a whole. In this case, the layer that is in direct contact with the wafer lens 91 and the fluorine-substituted layer 500 may be a high refractive index material layer (first layer 61) or a low refractive index material layer depending on the type of the wafer lens 91. It may be a layer (second layer 62). In the present embodiment, the layer that is in direct contact with the wafer lens 91 is a layer of a high refractive index material.

  In the production of the lens array 1 described above, as a mold for molding, a master mold (hereinafter simply referred to as “master”) 10 and a sub master mold (hereinafter simply referred to as “submaster”) 20 of FIG. Is used.

<Master>
As shown in FIG. 4A, the master 10 has a plurality of convex portions 14 formed in an array with respect to a rectangular parallelepiped base portion 12. The convex portion 14 is a portion corresponding to the lens portion 5 of the lens array 1 and protrudes in a substantially hemispherical shape. Note that the outer shape of the master 10 may be a quadrangle or a circle as described above. Although the scope of rights of the present invention is not limited by this difference, the following description will be made taking a rectangular shape as an example.
The optical surface shape (surface shape) of the master 10 may have a convex shape in which convex portions 14 are formed as shown in FIG. 4A, or a plurality of concave portions as shown in FIG. You may have the concave shape in which 16 was formed. However, the surface (molding surface) shape of the convex portions 14 and the concave portions 16 is positive corresponding to the optical surface shape (the shape of the surface opposite to the glass substrate 3) of the lens portion 5 molded and transferred onto the glass substrate 3. It has a shape. In the following description, the master 10 in FIG. 4 is distinguished as “master 10A”, and the master 10 in FIG. 5 is distinguished as “master 10B”.

As a material for the master 10A, when an optical surface shape is created by machining such as cutting or grinding, metal or metal glass can be used. The classification includes ferrous materials and other alloys. Examples of the iron system include hot dies, cold dies, plastic dies, high-speed tool steel, general structural rolled steel, carbon steel for mechanical structure, chromium / molybdenum steel, and stainless steel. Among them, plastic molds include pre-hardened steel, quenched and tempered steel, and aging treated steel. Examples of pre-hardened steel include SC, SCM, and SUS. More specifically, the SC system is PXZ. SCM systems include HPM2, HPM7, PX5, and IMPAX. Examples of the SUS system include HPM38, HPM77, S-STAR, G-STAR, STAVAX, RAMAX-S, and PSL. Examples of iron-based alloys include JP-A-2005-113161 and JP-A-2005-206913. As the non-ferrous alloys, copper alloys, aluminum alloys and zinc alloys are well known. Examples include the alloys disclosed in JP-A-10-219373 and JP-A-2000-176970. PdCuSi, PdCuSiNi, etc. are suitable as metallic glass materials because they have high machinability in diamond cutting and less tool wear. Amorphous alloys such as electroless and electrolytic nickel phosphorous plating are also suitable because they have good machinability in diamond cutting. These highly machinable materials may constitute the entire master 10A, or may cover only the surface of the optical transfer surface, in particular, by a method such as plating or sputtering.
Further, as the material of the master 10A, although machining is somewhat difficult, glass can also be used. If glass is used for the master 10A, the advantage of allowing UV light to pass through can also be obtained. If it is the glass generally used, it will not specifically limit.

In particular, examples of the molding material for the master 10A include materials that can easily ensure fluidity at a low temperature, such as low-melting glass and metal glass. The use of a low-melting glass is advantageous because it allows irradiation from the mold side of the sample when molding a UV curable material. Examples of the low melting point glass include glasses having a glass transition point of about 600 ° C. or lower and glass compositions of ZnO—PbO—B2O3, PbO—SiO2—B2O3, PbO—P2O5-SnF2, and the like. Examples of the glass that melts at 400 ° C. or less include PbF2-SnF2-SnO—P2O5 and similar structures. Specific materials include S-FPL51, S-FPL53, S-FSL 5, S-BSL 7, S-BSM 2, S-BSM 4, S-BSM 9, S-BSM10, S-BSM14, S-BSM15 , S-BSM16, S-BSM18, S-BSM22, S-BSM25, S-BSM28, S-BSM71, S-BSM81, S-NSL 3, S-NSL 5, S-NSL36, S-BAL 2, S- BAL 3, S-BAL11, S-BAL12, S-BAL14, S-BAL35, S-BAL41, S-BAL42, S-BAM 3, S-BAM 4, S-BAM12, S-BAH10, S-BAH11, S -BAH27, S-BAH28, S-BAH32, S-PHM52, S-PHM53, S-TIL 1, S-TIL 2, S-TIL 6, S-TIL25, S-TIL26, S-TIL27, S-TIM 1 , S-TIM 2, S-TIM 3, S-TIM 5, S-TIM 8, S-TIM22, S-TIM25, S-TIM27, S-TIM28, S-TIM35, S-TIM39, S-TIH 1, S-TIH 3, S-TIH 4, S-TIH 6, S-TIH10, S-TIH11, S-TIH13, S-TIH14, S-TIH18, S-TIH23, S-TIH53, S-LAL 7, S- LAL 8, S-LAL 9, S-LAL10, S-LAL12, S-LAL13, S-LAL14, S-LAL18, S-LAL54, S-LAL56, S-LAL58, S-LAL59, S-LAL61, S- LAM 2, S-LAM 3, S-LAM 7, S-LAM51, S-LAM52, S-LAM54, S-LAM55, S-LAM58, S-LAM59, S-LAM60, S-LAM61, S-LAM66, S -LAH51, S-LAH52, S-LAH53, S-LAH55, S-LAH58, S-LAH59, S-LAH60, S-LAH63, S-LAH64, S-LAH65, S-LAH66, S-LAH71, S-LAH79, S-YGH51, S-FTM16, S-NBM51, S-NBH 5, S-NBH 8, S-NBH51, S-NBH52, S-NBH53, S-NBH55, S-NPH1, S-NPH2, S-NPH53, P-FK01S, P-FKH2S, P-SK5S, P-SK12S, P-LAK13S, P-LASF03S, P-LASFH11S, P-LASFH12S and the like can be mentioned, but it is not necessary to be limited to these.
Similarly, metallic glass can be easily formed by molding. As the metallic glass, there are structures such as JP-A-8-109419, JP-A-8-333660, JP-A-10-81944, JP-A-10-92619, JP-A-2001-140047, JP-A-2001-303218, and JP-T-2003-534925. Although mentioned, it is not necessary to specifically limit to these.

The optical surface of the master 10A may be a surface on which a single convex portion 14 is formed, or may be a surface on which a plurality of convex portions 14 are formed in an array as shown in FIG. Good. As a method for creating the optical surface of the master 10A, there is diamond cutting.
If the optical surface of the master 10A is a surface on which a single convex portion 14 is formed, a diamond tool using a material such as nickel phosphorus, aluminum alloy, free-cutting cast or metal glass or amorphous alloy as a mold material. This can be realized by cutting.
If the optical surface of the master 10A is a surface on which a plurality of convex portions 14 are formed in an array, the optical surface shape is cut using a ball end mill B (see FIG. 6) in which cutting edges are formed of diamond. To do. At this time, the cutting edge of the tool is not a complete circular arc, and an error occurs in the machining shape depending on the place where the cutting edge is used. Therefore, when cutting any part of the optical surface shape, the position of the cutting edge to be used is the same. Thus, it is desirable to work while adjusting the tilt of the tool.
Specifically, first, the center of the cutting edge arc of the ball end mill B is positioned on the normal line of the machining surface at the point where the workpiece and the tool are in contact with the three translational axes. Further, the position B1 used by the cutting edge is positioned using the rotating shaft so as to come to the contact point between the workpiece and the tool. By continuously performing such tool position control, cutting of the optical surface shape is performed.
In order to perform such processing, the processing machine needs at least 3 translational degrees of freedom and 1 rotational degree of freedom, and can only be realized by a processing machine having a total of 4 or more degrees of freedom, so the optical surface of the master 10A is formed. In this case, a processing machine having 4 or more degrees of freedom is used.

<Submaster>
As shown in FIG. 4B, the sub master 20 includes a sub master molding portion 22 and a sub master substrate 26. A plurality of concave portions 24 are formed in the sub master molding portion 22 in an array. The surface (molding surface) shape of the concave portion 24 is a negative shape corresponding to the lens portion 5 in the lens array 1, and is concave in a substantially hemispherical shape in this figure.

≪Submaster molding part≫
The sub master molding part 22 is formed of resin 22A. As the resin 22A, a resin having good releasability, particularly a transparent resin is preferable. It is excellent in that it can be released without applying a release agent. As the resin, any of a photo-curing resin, a thermosetting resin, and a thermoplastic resin may be used.
Examples of the photocurable resin include a fluorine-based resin, and examples of the thermosetting resin include a fluorine-based resin and a silicone-based resin. Among them, a resin having good releasability, that is, a resin having a low surface energy when cured is preferable. Examples of the thermoplastic resin include transparent and relatively good releasable olefin resins such as polycarbonate and cycloolefin polymer. In addition, the release property is improved in the order of fluorine resin, silicone resin, and olefin resin. In this case, the sub master substrate 26 may be omitted. By using such a resin, it can be bent, so that it becomes more advantageous at the time of mold release.

Hereinafter, the fluorine resin, the silicone resin, and the thermoplastic resin will be described in detail.
(Fluorine resin)
Fluorocarbon resins include PTFE (polytetrafluoroethylene), PFA (tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer), FEP (tetrafluoroethylene / hexafluoropropylene copolymer (4,6 fluorinated)), ETFE (tetrafluoroethylene / ethylene copolymer), PVDF (polyvinylidene fluoride (difluoride)), PCTFE (polychlorotrifluoroethylene (trifluoride)), ECTFE (chlorotrifluoroethylene / ethylene copolymer) ), PVF (polyvinyl fluoride) and the like.
The advantages of fluororesins include mold releasability, heat resistance, chemical resistance, insulation, and low friction, but the disadvantage is that they are poor in transparency because they are crystalline. Since the melting point is high, a high temperature (about 300 ° C.) is required during molding.
Further, the molding method is cast molding, injection molding, extrusion molding, blow molding, transfer molding, etc. Among them, FEP, PFA, PVDF, etc. that are excellent in light transmittance and can be injection molding and extrusion molding are particularly preferable. .
Examples of great moldable grades include Fluon PFA manufactured by Asahi Glass, Dyneon PFA manufactured by Sumitomo 3M, and Dyneon THV. Particularly, the Dyneon THV series is preferable because it has a low melting point (about 120 ° C.) and can be molded at a relatively low temperature and is highly transparent.
As a thermosetting amorphous fluororesin, CYTOP Grade S manufactured by Asahi Glass is preferable because of its high transmittance and good releasability.

(Silicone resin)
Silicone resins include one-part moisture curing type and two-part addition reaction type and two-part condensation type.
Advantages include releasability, flexibility, heat resistance, flame retardancy, moisture permeability, low water absorption, and many transparent grades, but disadvantages include high linear expansion.
In particular, a silicone resin for mold making use that includes a PDMS (polydimethylsiloxane) structure is preferable because of good release properties, and a highly transparent grade of RTV elastomer is desirable. For example, TSE3450 from Momentive Performance Materials (two-component mixing, addition type), ELASTOSIL M 4647 (two-component RTV silicone rubber) from Asahi Kasei Wacker Silicone, and KE-1603 from Shin-Etsu Silicone (two-component mixing, addition) Type RTV rubber), SH-9555 (two-component mixed, addition type RTV rubber) manufactured by Toray Dow Corning, SYLGARD 184, Sylpot 184, WL-5000 series (photosensitive silicone buffer material, which can be patterned by UV) and the like are preferable.
In the case of a two-component RTV rubber, the molding method is room temperature curing or heat curing.

(Thermoplastic resin)
Examples of the thermoplastic resin include transparent resins such as alicyclic hydrocarbon resins, acrylic resins, polycarbonate resins, polyester resins, polyether resins, polyamide resins, and polyimide resins. A hydrocarbon-based resin is preferably used. If the submaster 20 is made of a thermoplastic resin, the injection molding technique that has been conventionally performed can be used as it is, and the submaster 20 can be easily manufactured. Further, if the thermoplastic resin is an alicyclic hydrocarbon-based resin, the hygroscopic property is very low, so the life of the submaster 20 is extended. In addition, since cycloaliphatic hydrocarbon resins such as cycloolefin resins are excellent in light resistance and light transmittance, in order to cure actinic ray curable resins, light having a short wavelength such as a UV light source may be used. There is little deterioration and it can be used as a mold for a long time.
Examples of the alicyclic hydrocarbon-based resin include those represented by the following formula (1).

In the above formula (1), “x” and “y” represent copolymerization ratios and are real numbers satisfying 0/100 ≦ y / x ≦ 95/5. “N” is 0, 1 or 2, and represents the number of substitutions of the substituent Q. “R ₁ ” is one or more (2 + n) -valent groups selected from a hydrocarbon group having 2 to 20 carbon atoms. “R ₂ ” is a hydrogen atom, or is one or two or more monovalent groups consisting of carbon and hydrogen and selected from the structural group having 1 to 10 carbon atoms. “R ₃ ” is one or two or more divalent groups selected from a hydrocarbon group having 2 to 20 carbon atoms. “Q” is represented by COOR ₄ (R ₄ is a hydrogen atom or a hydrocarbon, and is one or more monovalent groups selected from a structural group having 1 to 10 carbon atoms). It is 1 type or 2 or more types of monovalent group chosen from the structural group made.

  In the general formula (1), R1 is preferably one or more divalent groups selected from the group of hydrocarbon groups having 2 to 12 carbon atoms, more preferably the following general formula (2) ( In formula (2), p is an integer of 0-2.);

  And more preferably a divalent group in which p is 0 or 1 in the general formula (2). The structure of R1 may be used alone or in combination of two or more. Examples of R2 include a hydrogen atom, a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, a 2-methylpropyl group, etc., preferably a hydrogen atom and / or A methyl group, most preferably a hydrogen atom. As an example of R3, as a preferred example of a structural unit containing this group, when n = 0, for example, (a), (b), (c) (provided that in formulas (a) to (c), R1 Is as described above);

などが挙げられる。また、ｎは好ましくは０である。

Etc. N is preferably 0.

  In this embodiment, the type of copolymerization is not particularly limited, and known copolymerization types such as random copolymerization, block copolymerization, and alternating copolymerization can be applied, but random copolymerization is preferable. is there.

  In addition, the polymer used in the present embodiment has a repeating structural unit derived from another copolymerizable monomer as required, as long as the physical properties of the product obtained by the molding method of the present embodiment are not impaired. You may do it. The copolymerization ratio is not particularly limited, but is preferably 20 mol% or less, more preferably 10 mol% or less. When the copolymerization is further performed, the optical characteristics are impaired and a high-precision optical component is obtained. May not be obtained. The type of copolymerization at this time is not particularly limited, but random copolymerization is preferred.

  Another example of a preferred thermoplastic alicyclic hydrocarbon polymer applied to the submaster 20 is an alicyclic structure in which the repeating unit having an alicyclic structure is represented by the following general formula (4): The total content of the repeating unit (a) having a chain structure repeating unit (b) represented by the following formula (5) and / or the following formula (6) and / or the following formula (7) is 90. Examples thereof include a polymer that is contained in an amount of not less than mass%, and further the content of the repeating unit (b) is not less than 1 mass% and less than 10 mass%.

  In formula (4), formula (5), formula (6) and formula (7), R21 to R33 are each independently a hydrogen atom, a chain hydrocarbon group, a halogen atom, an alkoxy group, a hydroxy group, an ether group, Chains substituted with ester groups, cyano groups, amino groups, imide groups, silyl groups, and polar groups (halogen atoms, alkoxy groups, hydroxy groups, ester groups, cyano groups, amide groups, imide groups, or silyl groups) Represents a hydrocarbon group or the like. Specific examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. Examples of the chain hydrocarbon group substituted with a polar group include, for example, 1 to 20 carbon atoms, preferably The halogenated alkyl group of 1-10, More preferably, 1-6 is mentioned. As the chain hydrocarbon group, for example, an alkyl group having 1 to 20 carbon atoms, preferably 1 to 10 carbon atoms, more preferably 1 to 6 carbon atoms: 2 to 20 carbon atoms, preferably 2 to 10 carbon atoms, more preferably 2 to 2 carbon atoms. 6 alkenyl groups.

  X in the above formula (4) represents an alicyclic hydrocarbon group, and the number of carbon atoms constituting the group is usually 4 to 20, preferably 4 to 10, more preferably 5 to 7. It is. Birefringence can be reduced by setting the number of carbon atoms constituting the alicyclic structure within this range. The alicyclic structure is not limited to a monocyclic structure, and may be a polycyclic structure such as a norbornane ring.

The alicyclic hydrocarbon group may have a carbon-carbon unsaturated bond, but its content is 10% or less, preferably 5% or less, more preferably 3% or less of the total carbon-carbon bonds. is there. By setting the carbon-carbon unsaturated bond of the alicyclic hydrocarbon group within this range, transparency and heat resistance are improved. The carbon constituting the alicyclic hydrocarbon group includes a hydrogen atom, hydrocarbon group, halogen atom, alkoxy group, hydroxy group, ester group, cyano group, amide group, imide group, silyl group, and polar group ( A chain hydrocarbon group substituted with a halogen atom, an alkoxy group, a hydroxy group, an ester group, a cyano group, an amide group, an imide group, or a silyl group) may be bonded, and among them, the number of hydrogen atoms or carbon atoms 1 to 6 chain hydrocarbon groups are preferable in terms of heat resistance and low water absorption.
In addition, the above formula (6) has a carbon-carbon unsaturated bond in the main chain, and the above formula (7) has a carbon-carbon saturated bond in the main chain. When heat resistance is strongly required, the content of unsaturated bonds is usually 10% or less, preferably 5% or less, more preferably 3% or less, of all carbon-carbon bonds constituting the main chain.

  In this embodiment, the repeating unit (a) having an alicyclic structure represented by the general formula (4) in the alicyclic hydrocarbon copolymer, the general formula (5) and / or the general formula The total content with the repeating unit (b) having a chain structure represented by (6) and / or the general formula (7) is usually 90% or more, preferably 95% or more, more preferably 97 on a weight basis. % Or more. By setting the total content within the above range, low birefringence, heat resistance, low water absorption, and mechanical strength are highly balanced.

  As a production method for producing the alicyclic hydrocarbon-based copolymer, an aromatic vinyl-based compound is copolymerized with another monomer that can be copolymerized, and a carbon-carbon unsaturated bond of the main chain and the aromatic ring is formed. The method of hydrogenating is mentioned.

  The molecular weight of the copolymer before hydrogenation is 1,000 to 1,000,000, preferably 5,000 to 500,000 in terms of polystyrene (or polyisoprene) equivalent weight average molecular weight (Mw) measured by GPC. More preferably, it is in the range of 10,000 to 300,000. When the weight average molecular weight (Mw) of the copolymer is excessively small, the strength characteristics of the molded product of the alicyclic hydrocarbon copolymer obtained therefrom are inferior. Conversely, when the copolymer is excessively large, the hydrogenation reactivity is inferior.

  Specific examples of the aromatic vinyl compound used in the above method include, for example, styrene, α-methylstyrene, α-ethylstyrene, α-propylstyrene, α-isopropylstyrene, α-t-butylstyrene, 2- Methylstyrene, 3-methylstyrene, 4-methylstyrene, 2,4-diisopropylstyrene, 2,4-dimethylstyrene, 4-t-butylstyrene, 5-t-butyl-2-methylstyrene, monochlorostyrene, dichlorostyrene Monofluorostyrene, 4-phenylstyrene and the like, and styrene, 2-methylstyrene, 3-methylstyrene, 4-methylstyrene and the like are preferable. These aromatic vinyl compounds can be used alone or in combination of two or more.

  Other monomers that can be copolymerized are not particularly limited, but chain vinyl compounds and chain conjugated diene compounds are used. When chain conjugated dienes are used, the operability in the production process is excellent. The resulting alicyclic hydrocarbon copolymer is excellent in strength properties.

  Specific examples of the chain vinyl compound include chain olefin monomers such as ethylene, propylene, 1-butene, 1-pentene and 4-methyl-1-pentene; 1-cyanoethylene (acrylonitrile), 1-cyano- Nitrile monomers such as 1-methylethylene (methacrylonitrile) and 1-cyano-1-chloroethylene (α-chloroacrylonitrile); 1- (methoxycarbonyl) -1-methylethylene (methacrylic acid methyl ester), 1- (Ethoxycarbonyl) -1-methylethylene (methacrylic acid ethyl ester), 1- (propoxycarbonyl) -1-methylethylene (methacrylic acid propyl ester), 1- (butoxycarbonyl) -1-methylethylene (methacrylic) Acid butyl ester), 1-methoxycarboni (Meth) acrylic acid such as ethylene (acrylic acid methyl ester), 1-ethoxycarbonylethylene (acrylic acid ethyl ester), 1-propoxycarbonylethylene (acrylic acid propyl ester), 1-butoxycarbonylethylene (acrylic acid butyl ester) Ester monomers, 1-carboxyethylene (acrylic acid), 1-carboxy-1-methylethylene (methacrylic acid), unsaturated fatty acid monomers such as maleic anhydride, and the like are mentioned, among which chain olefin monomers are preferable, Most preferred are ethylene, propylene and 1-butene.

  Examples of the chain conjugated diene include 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, 1,3-hexadiene, and the like. Of these chain vinyl compounds and chain conjugated dienes, chain conjugated dienes are preferable, and butadiene and isoprene are particularly preferable. These chain vinyl compounds and chain conjugated dienes can be used alone or in combination of two or more.

  The polymerization reaction is not particularly limited, such as radical polymerization, anionic polymerization, and cationic polymerization. However, the polymerization operation, the ease of the hydrogenation reaction in the post-process, and the mechanical properties of the finally obtained hydrocarbon copolymer are not limited. In view of strength, the anionic polymerization method is preferable.

  In the case of anionic polymerization, bulk polymerization, solution polymerization, slurry polymerization, etc. in the temperature range of usually 0 ° C. to 200 ° C., preferably 20 ° C. to 100 ° C., particularly preferably 20 ° C. to 80 ° C. in the presence of an initiator. However, solution polymerization is preferable in view of removal of reaction heat. In this case, an inert solvent capable of dissolving the polymer and its hydride is used. Examples of the inert solvent used in the solution reaction include aliphatic hydrocarbons such as n-butane, n-pentane, iso-pentane, n-hexane, n-heptane, and iso-octane; cyclopentane, cyclohexane, methylcyclopentane, Examples thereof include alicyclic hydrocarbons such as methylcyclohexane and decalin; aromatic hydrocarbons such as benzene and toluene. Examples of the initiator for the anionic polymerization include monoorganolithium such as n-butyllithium, sec-butyllithium, t-butyllithium, hexyllithium, and phenyllithium, dilithiomethane, 1,4-diobane, and 1,4-dilithio. A polyfunctional organolithium compound such as 2-ethylcyclohexane can be used.

  When conducting hydrogenation reactions such as carbon-carbon double bonds of unsaturated rings such as aromatic rings and cycloalkene rings of the copolymer before hydrogenation, and unsaturated bonds of the main chain, the reaction method and reaction form are special. There is no particular limitation, and it may be carried out according to a known method, but a hydrogenation method that can increase the hydrogenation rate and has little polymer chain scission reaction that occurs simultaneously with the hydrogenation reaction is preferable, for example, in an organic solvent, nickel, The method is performed using a catalyst containing at least one metal selected from cobalt, iron, titanium, rhodium, palladium, platinum, ruthenium, and rhenium. The hydrogenation reaction is usually 10 ° C. to 250 ° C., but preferably 50 ° C. to 200 ° C. because the hydrogenation rate can be increased and the polymer chain scission reaction occurring simultaneously with the hydrogenation reaction can be reduced. More preferably, it is 80 degreeC-180 degreeC. The hydrogen pressure is usually 0.1 MPa to 30 MPa, but in addition to the above reasons, from the viewpoint of operability, it is preferably 1 MPa to 20 MPa, more preferably 2 MPa to 10 MPa.

The hydrogenation rate of the hydride obtained in this manner is determined by ¹ H-NMR, as determined by ¹ H-NMR, the main chain carbon-carbon unsaturated bond, the aromatic ring carbon-carbon double bond, the unsaturated ring carbon- All of the carbon double bonds are usually 90% or more, preferably 95% or more, more preferably 97% or more. When the hydrogenation rate is low, the low birefringence, thermal stability, etc. of the resulting copolymer are lowered.

  The method for recovering the hydride after completion of the hydrogenation reaction is not particularly limited. Usually, after removing the hydrogenation catalyst residue by a method such as filtration or centrifugation, the solvent is removed directly from the hydride solution by drying, the hydride solution is poured into a poor solvent for the hydride, and the hydride A method of coagulating can be used.

≪Sub-master board≫
Even if the submaster substrate 26 is inferior in strength only by the submaster molding portion 22 of the submaster 20, the strength of the submaster 20 can be increased by pasting resin on the substrate, and the submaster substrate 26 can be molded many times. It is a material.
The sub-master substrate 26 may be any material having smoothness such as quartz, silicone wafer, metal, glass, resin and the like.
From the viewpoint of transparency, considering that UV irradiation can be performed from above or below the submaster 20, a transparent mold such as quartz, glass, or transparent resin is preferable. The transparent resin may be a thermoplastic resin, a thermosetting resin, or a UV curable resin, and may have an effect of reducing the linear expansion coefficient by adding fine particles to the resin. By using resin in this way, it will be easier to release when it is released because it bends than glass, but since resin has a large coefficient of linear expansion, the shape will change if heat is generated during UV irradiation. There is a drawback that it cannot be transferred cleanly.

  Next, a manufacturing method of the lens array 1 will be described with reference to FIG.

As shown in FIG. 7A, a resin 22A is applied on the master 10A, the convex portions 14 of the master 10A are transferred to the resin 22A, the resin 22A is cured, and a plurality of concave portions 24 are formed on the resin 22A. Thereby, the sub master molding part 22 is formed.
The resin 22A may be thermosetting, photocurable, or volatile curable (the solvent is volatilized and cured, HSQ (hydrogen silsesquioxane or the like)). In the case where high-precision molding transferability is important, molding with UV curable or volatile curable resin, which is less affected by thermal expansion of resin 22A, is preferable because it does not apply heat to curing, but is not limited thereto. Since the resin 22A having good releasability from the master 10A after curing does not require a large force at the time of peeling, the molded optical surface shape and the like are more preferable without being inadvertently deformed.

  In the case where the resin 22A (the material of the sub-master molding part 22) and the resin 5A (the material of the lens part 5) are curable resins, the optical surface shape (convex part 14) of the master 10A is preferably cure shrinkage of the resin 22A. And designed in anticipation of cure shrinkage of resin 5A.

  When the resin 22A is applied on the master 10A, a technique such as spray coating, spin coating, dropping, or discharging is used. In this case, the resin 22A may be applied while evacuating. If the resin 22A is applied while evacuating, the resin 22A can be cured without introducing bubbles into the resin 22A.

In order to easily peel the cured resin 22A from the master 10A, it is preferable to apply a release agent to the surface of the master 10A.
When applying a release agent, the surface of the master 10A is modified. Specifically, an OH group is made to stand on the surface of the master 10A. The surface modification method may be any method that allows OH groups to stand on the surface of the master 10A, such as UV ozone cleaning and oxygen plasma ashing.
As the release agent, a material having a hydrolyzable functional group bonded to the end, such as a silane coupling agent structure, that is, dehydration condensation or hydrogen bonding with an OH group present on the metal surface is caused. And those having a structure that binds to each other. In the case of a release agent having a silane coupling structure at the end and a release function at the other end, the more OH groups are formed on the surface of the master 10A, the more covalently bonded portions on the surface of the master 10A. , A stronger bond is possible. As a result, no matter how many shots are formed, the release effect is not diminished and the durability is increased. Moreover, since a primer (underlayer, SiO ₂ coat, etc.) is not required, the effect of improving the durability can be obtained while keeping the thin film.

The material having a hydrolyzable functional group bonded to the terminal preferably includes a material composed of an alkoxysilane group, a halogenated silane group, a quaternary ammonium salt, a phosphate ester group or the like as a functional group. Further, the terminal group may be a group that causes a strong bond with the mold, such as triazine thiol. Specifically, it has an alkoxysilane group (8) or a halogenated silane group (9) represented by the following general formula.
-Si (OR1) nR2 (3-n) (8)
-SiXmR3 (3-m) (9)
Here, R1 and R2 are alkyl groups (eg, methyl, ethyl, propyl, butyl, etc.), n and m are 1, 2 or 3, and R3 is an alkyl group (eg, methyl, ethyl, propyl) Group, butyl group, etc.) or alkoxy group (for example, methoxy group, ethoxy group, butoxy group, etc.). X is a halogen atom (for example, Cl, Br, I).
Further, when two or more of R1, R2, R3 or X are bonded to Si, they may be different within the above group or atom range, for example, so that two Rm are an alkyl group and an alkoxy group. Good.
The alkoxysilane group —SiOR1 and the halogenated silane group —SiX react with moisture to become —SiOH, which further undergoes dehydration condensation or hydrogen bonding with the OH group present on the surface of the mold material such as glass or metal. Wake up and join.

FIG. 8 shows a reaction diagram of a release agent using an alkoxysilane group as an example of a hydrolyzable functional group at the terminal and an OH group on the surface of the master 10A.
In FIG. 8A, —OR represents methoxy (—OCH ₃ ) or ethoxy (—OC ₂ H ₅ ), and generates methanol (CH ₃ OH) or ethanol (C ₂ H ₅ OH) by hydrolysis. The silanol (—SiOH) in FIG. Thereafter, it is partially dehydrated and condensed to form a silanol condensate as shown in FIG. Further, as shown in FIG. 8 (d), it is adsorbed by OH groups and hydrogen bonds on the surface of the master 10 (inorganic material), and finally dehydrated as shown in FIG. To do. Although FIG. 8 shows the case of an alkoxysilane group, basically the same reaction occurs in the case of a halogenated silane group.
That is, the mold release agent used in the present invention is chemically bonded to the surface of the master 10A at one end and the functional group is oriented at the other end to cover the master 10A, and is thin and uniform in durability. A release layer can be formed.

A structure having a releasability function preferably has a low surface energy, such as a fluorine-substituted hydrocarbon group or a hydrocarbon group.
(Functional side is fluorine-based release agent)
Fluorine-substituted hydrocarbon groups include fluorine-substituted hydrocarbons that have perfluoro groups (a and b are integers) such as CF3 (CF2) a- and CF3 / CF3 / CF (CF2) b-groups at one end of the molecular structure. A hydrocarbon group is preferred, and the length of the perfluoro group is preferably 2 or more in terms of carbon number, and the number of CF2 groups following CF3 of CF3 (CF2) a- is suitably 5 or more.
Moreover, the perfluoro group does not need to be a straight chain and may have a branched structure. Furthermore, a structure such as CF3 (CF2) c- (CH2) d- (CF2) e- may be used in response to recent environmental problems. In this case, c is 3 or less, d is an integer (preferably 1), and e is 4 or less.
The above-mentioned fluorine release agent is usually a solid, but in order to apply it to the surface of the master 10A, it is necessary to make it a solution dissolved in an organic solvent. Depending on the molecular structure of the release agent, a fluorinated hydrocarbon solvent or a mixture of some organic solvent is suitable as the solvent. The concentration of the solvent is not particularly limited, but the required release film is characterized by being particularly thin. Therefore, a low concentration is sufficient, and it may be 1 to 3% by weight.
In order to apply this solution to the surface of the master 10A, a normal coating method such as dip coating, spray coating, brush coating, or spin coating can be used. After coating, the solvent is evaporated by natural drying to obtain a dry coating film. The film thickness applied at this time is not particularly specified, but 20 μm or less is appropriate.
Specific examples include Opkin DSX from Daikin Industries, Durasurf HD-1100, HD-2100, Novec EGC1720 from Sumitomo 3M, Triazine thiol from Takeuchi Vacuum Coating, Amorphous Fluorine Cytop Grade M from AGC, Antifouling from NI Material Coat OPC-800 etc. are mentioned.

(Functional side hydrocarbon release agent)
The hydrocarbon group may be linear, such as CnH2n + 1, or may be branched. Silicone release agents are included in this category.
Conventionally, a number of compositions are known as a composition mainly composed of an organopolysiloxane resin and forming a cured film exhibiting water repellency. For example, JP-A-55-48245 discloses a hydroxyl group-containing methylpolysiloxane resin, α, ω-dihydroxydiorganopolysiloxane, and organosilane, which are cured to provide excellent mold release and antifouling properties and water repellency. Compositions have been proposed that form the films shown. Japanese Patent Application Laid-Open No. 59-140280 discloses a composition mainly composed of a partial cohydrolysis condensate of an organosilane mainly composed of a perfluoroalkyl group-containing organosilane and an amino group-containing organosilane. A composition that forms a cured film excellent in oil repellency has been proposed.
Specific examples include AGC Seimi Chemical's mold spat, Matsumoto Fine Chemical's Olga Chicks SIC-330, 434, Toray Dow Chemical's SR-2410, and the like. Further, as a self-assembled monomolecular film, SAMLAY manufactured by Nippon Soda is cited.

When the resin 22A is a photocurable resin, the light source 50 disposed above the master 10A is turned on and irradiated with light.
Examples of the light source 50 include a high-pressure mercury lamp, a metal halide lamp, a xenon lamp, a halogen lamp, a fluorescent lamp, a black light, a G lamp, and an F lamp, and may be a linear light source or a point light source. Good. The high-pressure mercury lamp is a lamp having a narrow spectrum at 365 nm and 436 nm. A metal halide lamp is a kind of mercury lamp, and its output in the ultraviolet region is several times higher than that of a high-pressure mercury lamp. A xenon lamp is a lamp having a spectrum closest to sunlight. Halogen lamps contain a lot of long-wavelength light and are mostly near-infrared light. Fluorescent lamps have uniform illumination intensity for the three primary colors of light. Black light has a peak top at 351 nm and emits near-ultraviolet light of 300 nm to 400 nm.

In the case of irradiating light from the light source 50, a plurality of linear or point light sources 50 may be arranged in a lattice shape so that the light reaches the entire surface of the resin 22A at one time, or linear or dotted. The light source 50 may be scanned in parallel to the surface of the resin 22A so that the light sequentially reaches the resin 22A. In this case, preferably, a luminance distribution and an illuminance (intensity) distribution during light irradiation are measured, and the number of irradiations, irradiation amount, irradiation time, and the like are controlled based on the measurement results.
After the resin 22A is photocured (after the production of the submaster 20), the submaster 20 may be post-cured (heat treatment). If post cure is performed, the resin 22A of the submaster 20 can be completely cured, and the mold life of the submaster 20 can be extended.

  When the resin 22A is a thermosetting resin, the resin 22A is heated while controlling the heating temperature and the heating time within an optimum range. The resin 22A can be molded by a technique such as injection molding, press molding, light irradiation and then cooling.

As shown in FIG. 7B, the sub master substrate 26 is mounted on the back surface (the surface opposite to the concave portion 24) of the sub master molding portion 22 (resin 22A), and the sub master molding portion 22 is lined.
The sub master substrate 26 may be quartz or a glass plate, and it is important to have sufficient bending strength and UV transmittance. In order to improve the adhesion between the sub-master molding part 22 and the sub-master substrate 26, a treatment such as applying a silane coupling agent to the sub-master substrate 26 may be performed.

As described above, when the sub master substrate 26 is mounted after the convex portion 14 of the master 10A is transferred to the resin 22A and the resin 22A is cured (that is, after the sub master molding portion 22 is formed). Use glue.
Conversely, the sub-master substrate 26 may be mounted before the convex portion 14 of the master 10A is transferred to the resin 22A and the resin 22A is cured. In this case, without using an adhesive, the sub-master substrate 26 is attached by the adhesive force of the resin 22A, or a coupling agent is applied to the sub-master substrate 26 to increase the adhesive force and thereby apply the resin 22A to the resin 22A. On the other hand, the sub master substrate 26 is attached. For example, a thermosetting resin is used as the resin 22A, and the resin 22A is filled between the master 10A and the sub master substrate 26, and then these are put into a baking furnace. Or a UV curable resin as the resin 22A, a UV transmissive substrate as the sub master substrate 26, and the sub master substrate in a state where the resin 22A is filled between the master 10A and the sub master substrate 26. There is a method of irradiating the resin 22A with UV light from the 26 side.

  Further, when backing the sub master molding portion 22 (resin 22A) with the sub master substrate 26, a conventionally known vacuum chuck device 260 is used, and the sub master substrate 26 is sucked to the suction surface 260A of the vacuum chuck device 260. While holding, it is preferable that the suction surface 260A is parallel to the molding surface of the convex portion 14 in the master 10A, and the sub master molding portion 22 is lined with the sub master substrate 26. Thereby, the back surface 20A of the sub master 20 (surface on the sub master substrate 26 side) is parallel to the molding surface of the convex portion 14 in the master 10A, and the molding surface of the recess 24 in the sub master 20 is parallel to the back surface 20A. . Therefore, when the lens unit 5 is molded by the submaster 20 as will be described later, the reference surface of the submaster 20, that is, the back surface 20 </ b> A can be made parallel to the molding surface of the recess 24. Or variation in thickness, the shape accuracy of the lens unit 5 can be improved, and the lens performance can be maintained high. Further, since the sub master 20 is sucked and held by the vacuum chuck device 260, the sub master 20 can be attached and detached only by turning on / off the vacuum exhaust. Therefore, the sub master 20 can be easily arranged. In addition, the master 10A is most carefully and gently peeled off from the master 10A if the master 10A is sucked and held by the second vacuum chuck device parallel to the suction surface 260A of the vacuum chuck device 260 described above. For work that requires attention, the vacuum chuck can be turned off while the two are cured and in close contact with each other, making it easy to remove from the molding equipment. It can be carried out. Further, when another master and a sub master substrate are attached to the molding apparatus by a vacuum chuck during the operation, the sub master can be continuously molded.

  Here, the back surface 20A being parallel to the molding surface of the recess 24 specifically means that the back surface 20A is perpendicular to the central axis of the molding surface of the recess 24.

  The suction surface 260A of the vacuum chuck device 260 is preferably made of a ceramic material. In this case, the hardness of the suction surface 260A is increased, and the suction surface 260A is hardly damaged by the attachment / detachment of the submaster 20 (submaster substrate 26), so that the surface accuracy of the suction surface 260A can be maintained high. . Moreover, it is preferable to use silicon nitride or sialon as such a ceramic material. In this case, since the linear expansion coefficient is as small as 1.3 ppm, the flatness of the suction surface 260A can be kept high with respect to the temperature change.

In the present embodiment, the following method is used as a method for bringing the suction surface 260A into a parallel state with respect to the molding surface of the convex portion 14 in the master 10A.
First, the front and back surfaces of the master 10A are parallelized with high accuracy. Thereby, in the master 10A, the shaping | molding surface and back surface of the convex part 14 become parallel.
In addition, reference members 260C and 260D are provided so as to protrude from the support surface 260B that supports the master 10A from the back surface (surface opposite to the convex portion 14) and the suction surface 260A, respectively. Here, the shapes of these reference members 260C and 260D are such that when the master 10A and the sub master 20 come into contact with each other in a state where the support surface 260B and the suction surface 260A are parallel to each other, there is no backlash.
Thus, by bringing the reference members 260C and 260D into contact with each other, the support surface 260B of the master 10A and eventually the molding surface of the convex portion 14 of the master 10 are parallel to the suction surface 260A.

  However, in the method as described above, the reference member may be provided on at least one of the support surface 260B and the suction surface 260A. For example, when the reference member is provided only on the support surface 260B, the shape of the reference member is When the master 10A and the sub master 20 are in contact with each other in a state where the surface 260B and the suction surface 260A are parallel to each other, the shape may be configured to contact the suction surface 260A without backlash. Similarly, when the reference member is provided only on the suction surface 260A, the shape of the reference member is such that when the master 10A and the sub master 20 are in contact with each other with the support surface 260B and the suction surface 260A being parallel to each other, What is necessary is just to make it the shape which contact | abuts with respect to the support surface 260B without backlash. Such parallelism by mechanical contact can realize reproducibility of about a few seconds without having a special alignment device.

As shown in FIG. 7C, the sub master 20 is formed by releasing the sub master molding portion 22 and the sub master substrate 26 from the master 10A.
When a resin such as PDMS (polydimethylsiloxane) is used as the resin 22A, the releasability from the master 10 is very good, so that a large force is not required for peeling from the master 10, and the molding optical surface is distorted. It ’s good because there ’s nothing.

  As shown in FIG. 7D, a resin 5A is filled between the sub master 20 and the glass substrate 3 and cured. More specifically, the resin 5A is filled in the recess 24 of the submaster 20, and the resin 5A is cured while pressing the glass substrate 3 from above.

When the resin 5A is filled in the recess 24 of the sub master 20, the resin 5A may be filled while evacuating. If the resin 5A is filled while evacuating, the resin 5A can be cured without introducing bubbles into the resin 5A.
Instead of filling the recess 24 of the sub master 20 with the resin 5A, the resin 5A may be applied to the glass substrate 3, and the glass substrate 3 coated with the resin 5A may be pressed against the sub master 20.

  When the glass substrate 3 is pressed, the glass substrate 3 is preferably provided with a structure for axial alignment with the submaster 20. When the glass substrate 3 has a circular shape, for example, it is preferable to form a D cut, an I cut, a marking, a notch, or the like. The glass substrate 3 may have a polygonal shape, and in this case, the axis alignment with the submaster 20 is easy. Further, a marker pattern for matching the coaxiality with the front-side molding optical surface at the time of molding the back surface of the glass substrate 3 may be molded and transferred simultaneously with the optical surface at the time of molding the front-surface side.

  When the resin 5A is to be cured, the light source 52 disposed below the sub master 20 may be turned on to emit light from the sub master 20 side, or the light source 54 disposed above the glass substrate 3 may be turned on to turn on the glass substrate. The light may be irradiated from the 3 side, or both the light sources 52 and 54 may be turned on simultaneously, and the light may be irradiated from both the sub master 20 side and the glass substrate 3 side.

  As the light sources 52 and 54, the same high-pressure mercury lamp, metal halide lamp, xenon lamp, halogen lamp, fluorescent lamp, black light, G lamp, F lamp as the light source 50 described above can be used. It may be a point light source.

  When irradiating light from the light sources 52 and 54, a plurality of linear or point light sources 52 and 54 may be arranged in a lattice shape so that the light reaches the resin 5A at one time. The point light sources 52 and 54 may be scanned in parallel to the submaster 20 and the glass substrate 3 so that the light sequentially reaches the resin 5A. In this case, preferably, a luminance distribution and an illuminance (intensity) distribution during light irradiation are measured, and the number of irradiations, irradiation amount, irradiation time, and the like are controlled based on the measurement results.

  When the resin 5A is cured, the lens portion 5 is formed. Thereafter, the lens unit 5 and the glass substrate 3 are released from the sub-master 20, and a molded product of the lens array 1 is manufactured (the molded product has the lens unit 5 formed only on the surface of the glass substrate 3). is there.).

When the molded product of the lens array 1 is released from the sub master 20, a tensile sheet 60 is provided in advance between the molded product (glass substrate 3) and the sub master 20, and the tensile sheet 60 is pulled to form the molded product. May be released from the sub-master 20.
When the submaster substrate 26 of the submaster 20 is an elastic material (resin), it may be bent slightly to release the molded product from the submaster 20, or the glass substrate 3 is elastic instead of glass. Even in the case of a material (resin), the molded product may be released from the sub master 20 by slightly bending it.
When the molded product is slightly peeled from the sub master 20 and a gap is formed between both members, air or pure water may be pumped into the gap and the molded product may be released from the sub master 20.

  In the above description, the method of providing the lens unit 5 on one side of the glass substrate 3 has been described. However, when the lens unit 5 is provided on both sides, first, it corresponds to the optical surface shape of the lens unit 5 on one side of the glass substrate 3. A master (not shown) having a plurality of positive molding surfaces and a master having a plurality of positive molding surfaces corresponding to the optical surface shape of the lens portion 5 on the other surface are prepared, and each of these masters is used. Thus, the sub masters 20C and 20D (see FIGS. 7E and 7F) are formed. Accordingly, the sub master 20C has a negative molding surface corresponding to the optical surface shape of the lens portion 5 on one surface of the glass substrate 3, and the sub master 20D corresponds to the optical surface shape of the lens portion 5 on the other surface. Will have a negative shaped molding surface. And after filling resin 5A between each submaster 20C and 20D and the glass substrate 3, the resin 5A is hardened simultaneously and the lens part 5 is shape | molded on both surfaces of the glass substrate 3. FIG. According to this, the resin 5A does not cure and shrink on only one side of the glass substrate 3, and the resin 5A cures and shrinks simultaneously on both sides to become the lens parts 5, respectively. In contrast, since the warp of the glass substrate 3 can be prevented, the shape accuracy of the lens portion 5 can be improved. Note that the simultaneous curing of the resin 5A on both surfaces of the glass substrate 3 means that the resin 5A is completely cured in the same curing process, and it is not always necessary to start and end the curing simultaneously. After the resin 5A between the glass substrate 3 is thickened to a predetermined viscosity, the resin 5A and the other resin 5A may be completely cured.

Here, in order to fill the resin 5 </ b> A between the sub masters 20 </ b> C and 20 </ b> D and the glass substrate 3, three methods can be used.
In the first method, as shown in FIGS. 7E and 7F, after the resin 5A is dropped or discharged onto the upper surface of the sub master 20C, the sub master 20C and the glass disposed above the sub master 20C are disposed. After the substrate 3 is brought into contact with the glass substrate 3 and the sub master 20C so as to be filled with the resin 5A, the glass substrate 3 and the sub master 20C are integrally turned upside down while being in contact with each other. Then, after the resin 5A is dropped or discharged on the upper surface of the sub master 20D, the sub master 20D is brought into contact with the glass substrate 3 disposed above the sub master 20D so that the sub master 20D is placed between the glass substrate 3 and the sub master 20D. The resin 5A is filled. When the glass substrate 3 and the sub master 20C are turned upside down in a state where they are in contact with each other, if both are sucked and held by the vacuum chuck, this can be easily realized by this OFF / ON operation.
In the second method, after the resin 5A is dropped or discharged on the upper surface of the glass substrate 3, the glass substrate 3 and the sub master 20C disposed above the glass substrate 3 are brought into contact with each other. The resin 5A is filled between the sub masters 20C, and after the resin 5A is dropped or discharged onto the upper surface of the sub master 20D, the sub master 20D and the glass substrate 3 disposed thereabove are contacted. The resin 5A is filled between the glass substrate 3 and the submaster 20D.
In the third method, molding and curing are sequentially performed for each optical surface on one side of the glass substrate 3, but the first molding surface is not released until the molding and curing on both sides is completed to prevent warping due to curing shrinkage. Therefore, in the first curing molding, the sub master 20C performs molding of the opposite surface by the sub master 20D while the filled resin 5A remains in contact after curing. The glass substrate 3 is molded by the sub-master 20C, and a tensile force is applied to the molding surface side due to the curing shrinkage of the resin 5A. However, warping is prevented by receiving this while the sub-master 20C is in contact. In this state, when the sub-master 20D is filled with the resin 5A on the opposite surface and molded and cured, the glass substrate 3 remains anti-balanced even if the sub-masters 20C and 20D are released in balance with the tensile force due to the curing shrinkage on this side. It will not be.
In addition, when making the glass substrate 3 and submaster 20C, 20D contact | abut, it is preferable not to leave a bubble between them. The resin 5A used here may be a thermosetting resin, a UV curable resin, or a volatile curable resin (HSQ or the like). When a UV curable resin is used, at least one of the sub-masters 20C and 20D is made to be UV transmissive so that the UV light is simultaneously irradiated to the resin 5A on both surfaces of the glass substrate 3 from the one sub-master side. can do.

  Here, in the case where the lens portions 5 are formed on the front and back surfaces of the glass substrate 3, as shown in FIG. 9, the sub master 20 is doubled vertically and horizontally (the magnification can be changed). When the diameter sub-master 200 and the normal sub-master 20 of FIG. 10 are prepared and the lens unit 5 is formed on the surface of the glass substrate 3, the sub-master 200 is used, and the lens unit 5 is disposed on the back surface on the opposite side. When forming the sub master 20, the sub master 20 may be used a plurality of times.

  Specifically, the lens portion 5 is collectively formed on the surface of the glass substrate 3 using the large-diameter submaster 200. On the rear surface of the glass substrate 3 thereafter, as shown in FIG. 11, the lens unit 5 is formed using the submaster 20 four times while shifting the submaster 20 by ¼ sections of the large-diameter submaster 200. To do. According to such a configuration, the axis alignment of the sub master 20 is easy with respect to the glass substrate 3 having the lens portion 5 formed using the large-diameter submaster 200, and the lens formed using the large-diameter submaster 200. It is possible to suppress a situation in which the portion 5 and the lens portion 5 formed using the sub master 20 are misaligned on the front and back of the glass substrate 3.

  However, when the large-diameter submaster 200 is used, as shown in the upper to lower stages of FIG. 12, there is a possibility that the submaster molding portion 22 may be slightly warped, so that the original function as a mold is exhibited. Sometimes you can't. Therefore, as shown in FIG. 13, a region where the resin 22 </ b> A does not exist in a cross shape (stress relaxation portion 210) is provided at the center so as to divide the large-diameter submaster 200, and It is preferable to adopt a configuration that suppresses the occurrence of warpage 22 (relaxes stress with the glass substrate 3).

  In the case where the stress relieving portion 210 is provided, for example, when the resin 22A is a photocurable resin, the glass substrate 3 or the sub master substrate 26 is masked to form an unirradiated portion of light, or the light sources 52 and 54 are masked. Thus, an unirradiated portion of light may be formed.

Instead of the master 10A, the master 10B may be used, and the molded product of the lens array 1 may be manufactured directly from the master 10B without manufacturing the sub-master 20.
In this case, the recess 5 of the master 10B is filled with the resin 5A, the resin 5A is cured while pressing the glass substrate 3 from above, and then the glass substrate 3 and the lens unit 5 are released from the master 10B. . The curing means of the resin 5A differs depending on the resin material. For example, when a UV curable resin is used, UV curing is performed from the glass substrate 3 side, but when a thermosetting resin is used, an infrared lamp or a master 10B is used. It is cured by heating with an embedded heater.
Mold release for peeling the resin 5A from the master 10B is important, and two types of methods can be considered as the mold release method.

As a first method, a release agent is added to the resin 5A. In this case, since the adhesion of the antireflection coating, which is a subsequent process, is lowered or the adhesion to the glass substrate 3 is lowered, a coupling agent or the like is preferably applied to the glass substrate 3 for the latter. To strengthen the adhesion.
As a second method, a release agent is coated on the surface of the master 10B. As the release agent, a release agent that forms triazine dithiol, a fluorine-based, or a silicon-based monomolecular layer can be used. By using the mold release agent, the film can be coated to a thickness that does not affect the optical surface shape, such as about 10 nm. In order to improve the adhesion so that the mold release agent does not peel off during molding, a coupling agent is applied to the master 10B, or SiO ₂ or the like that creates a bridge between the mold release agent and the master 10B is used as the master 10B. If it is coated, the adhesion may be strong.

  Then, the lens array 1 is manufactured by exposing the molded product of the lens array 1 formed as described above to fluorine gas to form the fluorine substitution layer 500 on the surface of the lens portion 5.

Next, a method for manufacturing the electronic device 100 will be described with reference to FIG.
First, an antireflection film 92 is formed on the lens array 1 manufactured as described above.

Here, the antireflection film 92 is formed as follows. First, the lens array 1 (the lens array 1 without the antireflection film 92) is mounted in a vacuum deposition apparatus, and the pressure in the apparatus is reduced to a predetermined pressure (for example, 2 × 10 ⁻³ Pa), and vacuum is applied. The lens array 1 is heated by a heater at the top of the vapor deposition apparatus until the temperature reaches a predetermined temperature (eg, 240 ° C.).

Thereafter, the first layer 61 is formed using a vapor deposition source constituting the first layer 61. In particular, in this case, the film forming temperature is maintained within a range of −40 to + 40 ° C. with respect to the melting temperature of the conductive paste to be melted by the reflow process.
For example, when a (Ta ₂ O ₅ + 5% TiO ₂ ) film is formed as the first layer 61, OA600 manufactured by Optron is used as an evaporation source, and the evaporation source may be evaporated by electron gun heating. During vapor deposition, it is preferable to form a film while introducing an O ₂ gas up to a pressure of 1.0 × 10 ⁻² Pa inside the vacuum vapor deposition apparatus and controlling the vapor deposition rate at 5 Å / sec. When the melting temperature of the conductive paste to be melted by the reflow process is 240 ° C., for example, the film forming temperature (temperature in the vapor deposition apparatus) is maintained within the range of 200 to 280 ° C.

  Thereafter, in order to form the first layer 61 on both surfaces of the lens array 1, the lens array 1 is reversed by a reversing mechanism inside the vapor deposition apparatus, and the first layer 61 is also formed on the back surface thereof in the same manner as above (second). The same applies to the film formation on the back surface of the layer 62).

Thereafter, the second layer 62 is formed on the first layer 61 using the vapor deposition source constituting the second layer 62. Also in this case, as in the case of forming the first layer 61, the film forming temperature is maintained within the range of −40 to + 40 ° C. with respect to the melting temperature of the conductive paste to be melted by the reflow process.
For example, when a SiO ₂ film is formed as the second layer 62, O ₂ gas is introduced until the pressure inside the vacuum vapor deposition apparatus is 1.0 × 10 ⁻² Pa, and the vapor deposition rate is controlled to 5 liters / sec. It is better to form the film while doing so. When the melting temperature of the conductive paste to be melted by the reflow process is 240 ° C., for example, the film forming temperature (temperature in the vapor deposition apparatus) is maintained within the range of 200 to 280 ° C.
Through the above steps, the antireflection film 92 can be formed on the lens array 1.

  Next, the lens array 1 is cut and divided into second and third optical members 912 and 913 to manufacture a plurality of wafer lenses 91, and the substrate module 105 and the lens module 106 are assembled using the wafer lenses 91. As shown in FIG. 14A, the mounting portion 150b of the lens case 150 is attached to the mounting hole of the sub-board 130 until the lower end of the collar member 190 mounted in advance in the lens case 150 contacts the upper surface of the sub-board 130. The imaging module 102 is formed by being inserted and fixed in 130a.

  After that, as shown in FIG. 14B, the imaging module 102 and other electronic components are placed at a predetermined mounting position of the circuit board 101 to which a conductive material 180 such as solder has been applied (potted) in advance. Thereafter, as shown in FIG. 14C, the circuit board 101 on which the imaging module 102 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 101 is moved at 230 to 270 ° C. Heat (reflow treatment) at about a temperature for about 5 to 10 minutes. As a result of the reflow processing, the conductive material 180 is melted and the imaging module 102 is mounted on the circuit board 101 together with other electronic components, and the electronic device 100 is manufactured by incorporating this into the cover case 103.

  According to the above embodiment, since the antireflection film 92 on the wafer lens 91 is formed of an inorganic material, the heat resistance against the reflow process is improved as compared with the case of being formed of an organic material. Can do. Further, since the surface of the lens portion 5 in the wafer lens 91 is substituted with fluorine, the occurrence of cracks and film peeling in the antireflection film 92 can be prevented (see the following examples). Moreover, the electronic device 100 can be manufactured at low cost by using the imaging lens 9 having such an imaging lens 91 for the reflow process.

[Second Embodiment]
The second embodiment is mainly different from the first embodiment in the following points, and is otherwise substantially the same.

  In manufacturing the lens array 1, the master 10, the sub master 30, and the sub sub master 40 shown in FIG. 5 are used as molds for molding. In the first embodiment, the sub-master 20 is used to manufacture the lens array 1 from the master 10 (10A), whereas in the second embodiment, the lens array 1 is mainly from the master 10 (10B). The difference is that two types of sub-master 30 and sub-sub-master 40 are used to manufacture the sub-master. In particular, the process of manufacturing the sub master 30 from the master 10B and the process of manufacturing the lens array 1 from the sub sub master 40 are substantially the same as those in the first embodiment, and the first is that the sub sub master 40 is manufactured from the sub master 30. This is different from the embodiment.

  As shown in FIG. 5A, the master 10 </ b> B is a mold in which a plurality of concave portions 16 are formed in an array shape with respect to a rectangular parallelepiped base portion 12. The shape of the concave portion 16 is a negative shape corresponding to the lens portion 5 of the lens array 1, and is concave in a substantially hemispherical shape in this figure. The outer shape of the master 10B does not have to be a quadrangle and may be a circle, but here, a quadrangle will be described as an example.

  The master 10B may be a material such as nickel phosphorus, aluminum alloy, free-cutting cast metal, etc., created by cutting an optical surface with high precision by diamond cutting, or by grinding a hard material such as carbide. It may also have been created. The optical surface created by the master 10B is preferably one in which a plurality of concave portions 16 are arranged in an array as shown in FIG. 5 (a), and only a single concave portion 16 is arranged. Also good.

  As shown in FIG. 5B, the sub master 30 includes a sub master molding part 32 and a sub master substrate 36. A plurality of convex portions 34 are formed in an array on the sub master molding portion 32. The shape of the convex portion 34 is a positive shape corresponding to the lens portion 5 of the lens array 1 and protrudes in a substantially hemispherical shape in this figure. The sub master molding part 32 is formed of a resin 32A.

The resin 32A can basically use the same material as the resin 22A of the sub-master 20 of the first embodiment, but is particularly releasable and heat resistant, and has a small linear expansion coefficient (ie It is preferable to use a resin having a small surface energy. Specifically, any of the above-mentioned photo-curing resin, thermosetting resin, and thermoplastic resin may be used, and it may be transparent or opaque. For example, if it is a thermosetting resin, the above-mentioned fluorine-based resin may be used. is necessary. This is because when the silicone resin is used, the coefficient of linear expansion is large, so that it deforms when thermally transferred to the sub-submaster 40, and the fine structure cannot be accurately transferred.
The sub master substrate 36 can use the same material as the sub master substrate 26.

  As shown in FIG. 5C, the sub-sub master 40 includes a sub-sub master molding portion 42 and a sub-sub master substrate 46. A plurality of recesses 44 are formed in an array in the sub-submaster molding part 42. The concave portion 44 is a portion corresponding to the lens portion 5 of the lens array 1 and is concave in a substantially hemispherical shape. The sub-sub master molding part 42 is formed of a resin 42A.

The resin 42A can use the same material as the resin 22A of the submaster 20 of the first embodiment, but uses a silicone resin or an olefin resin because it can be bent and easily released. It is preferable to do.
A material similar to that of the sub master substrate 26 can also be used for the sub sub master substrate 46.

  Next, a manufacturing method of the lens array 1 will be briefly described with reference to FIGS.

  As shown in FIG. 15A, a resin 32A is applied on the master 10B, the resin 32A is cured, and the concave portions 16 of the master 10B are transferred to the resin 32A, thereby forming a plurality of convex portions 34 on the resin 32A. Thereby, the submaster molding part 32 is formed.

As shown in FIG. 15B, the sub master substrate 36 is bonded to the sub master molding portion 32.
Thereafter, as shown in FIG. 15C, the sub master molding part 32 and the sub master substrate 36 are released from the master 10B, and the sub master 30 is manufactured.
Thereafter, as shown in FIG. 15D, a resin 42A is applied on the sub master 30, the resin 42A is cured, and the convex portions 34 of the sub master 30 are transferred to the resin 42A. Form. Thereby, the sub-submaster molding part 42 is formed.
Thereafter, as shown in FIG. 15 (e), the sub-sub master substrate 46 is mounted on the sub-sub master molding portion 42.

  As shown in FIG. 16 (f), the sub-submaster 40 is fabricated by releasing the sub-submaster molding part 42 and the sub-submaster substrate 46 from the submaster 30.

  As shown in FIG. 16G, the recess 5 of the sub-submaster 40 is filled with the resin 5A, and the resin 5A is cured while pressing the glass substrate 3 from above. As a result, the lens portion 5 is formed from the resin 5A. Thereafter, the lens unit 5 and the glass substrate 3 are released from the sub-submaster 40 to manufacture the lens array 1 (the lens array 1 is formed by forming the lens unit 5 only on the surface of the glass substrate 3). ).

  When the lens unit 5 is formed on the back surface of the glass substrate 3 and the lens unit 5 is formed on both the front and back surfaces of the glass substrate 3, it corresponds to the optical surface shape of the lens unit 5 on one surface of the glass substrate 3. A master (not shown) having a plurality of negative-shaped molding surfaces and a master having a plurality of negative-shaped molding surfaces corresponding to the optical surface shape of the lens portion 5 on the other surface are prepared, and each of these masters is used. Then, a sub master having a positive molding surface is formed, and further, a sub sub master is formed using each of these sub masters. And after filling resin 5A between each sub-submaster and the glass substrate 3, the resin 5A is hardened and the lens part 5 is shape | molded on both surfaces of the glass substrate 3. FIG.

  In the above embodiment, the optical element according to the present invention has been described as the imaging lens 9. However, other types and applications of optical elements may be used.

  Hereinafter, the optical element according to the present invention will be described more specifically by giving examples and comparative examples. However, the present invention is not limited to the examples.

[Sample preparation]
As Examples and Comparative Examples of the present invention, samples (1) to (12) as shown in Table 1 below were prepared.

Specifically, various UV curable resins having heat resistance were selected as the resin of the lens unit 5 (see “resin” column in the table).
Here, in the table, “acrylic” refers to 2-alkyl-2-adamantyl (meth) acrylate as a curable resin prepared according to the method disclosed in JP-A-2002-193883 as a UV curing initiator. An IRGACURE907 added with 1 wt% is shown.
“Epoxy” refers to hydrogenated bisphenol A type epoxy resin with 4 wt% of UVI-6992 added as a UV curing initiator.
“Allyl ester” refers to a compound containing 1% by weight of IRGACURE907 as a UV initiator with respect to a bromine-containing (meth) allyl ester not containing an aromatic ring (see JP-A-2003-66201).

  In the table, the “fluorine gas substitution” column indicates whether or not the fluorine substitution layer 500 is formed on the surface of the lens unit 5. This fluorine gas replacement was performed by exposing the molded article of the lens array 1 for 2 minutes in 5% concentration of fluorine gas under conditions of 1.1 atm and 25 ° C.

  Further, in the table, the column of “organic film lamination” indicates whether or not an organic material layer is laminated on the surface of the lens unit 5. This organic film was laminated by the method of “Specific Example 6” in Patent Document 3.

In the table, “AR coating” means an antireflection film. This antireflection film was formed on the surface of the lens portion 5 in the molded article of the lens array 1 by a vacuum deposition method. Specifically, first, the lens array 1 is mounted in a vacuum deposition apparatus, the pressure in the apparatus is reduced to 2 × 10 ⁻³ Pa, and the lens array 1 is brought to a temperature of 240 ° C. by a heater at the top of the vacuum deposition apparatus. Heated until. Next, in order to form a (Ta ₂ O ₅ + 5% TiO ₂ ) film having a thickness of 20 nm on the lens array 1, OA600 manufactured by Optron is used as a film material, and this is evaporated by heating with an electron gun. A (Ta ₂ O ₅ + 5% TiO ₂ ) film was formed thereon. Here, at the time of vapor deposition, O ₂ gas was introduced until the pressure in the vacuum vapor deposition apparatus became 1.0 × 10 ⁻² Pa, and vapor deposition was performed while controlling the evaporation rate at 5 kg / sec. Subsequently, O ₂ gas was introduced until the pressure inside the vacuum deposition apparatus reached 1.2 × 10 ⁻² Pa, and deposition of an SiO ₂ film of 110 nm was performed while controlling the evaporation rate at 5 Å / sec.

[Sample evaluation] (Reflow heat resistance evaluation of resin base material)
Difference in total light transmittance due to coloring before and after leaving only the resin base material (lens array without antireflection film and fluorine substitution layer) in each material (1) to (12) under reflow conditions at 260 ° C. for 30 minutes Was measured according to the following criteria, and the results were as shown in the column of Table 1 “Reflow heat resistance test of resin base material”.
○: Less than -2% ×: -2% or more

(Evaluation of reflow heat resistance after formation of antireflection film and fluorine substitution layer)
Each material (1) to (12) is allowed to stand under reflow conditions at 260 ° C. for 30 minutes, and the difference in total light transmittance due to coloring before and after the measurement is measured. When observed with a stereomicroscope and evaluated according to the following criteria, the results were as shown in the column of Table 1 “Reflow heat resistance test with AR coating”.
○: Transmittance difference is less than −2% and no cracks are observed on the surface Δ Coloring: Transmittance difference is −2% or more and less than −5% × Coloring: Transmittance difference is -5% or more ΔCrack: 1 or more and 4 or less cracks are observed in the antireflection film × Crack: 5 or more cracks are observed on the surface

(Evaluation of film peeling after deposition of antireflection film)
For each of the materials (2), (4), (6), (8), (10), and (12) on which the antireflection film is deposited, a cotton swab is immersed in IPA, and the lens surface is reciprocated with a load of 10 g. When the presence or absence of film peeling of the antireflection film was evaluated according to the following criteria, it was as shown in the column of Table 1 “Presence or absence of film peeling after AR coating deposition”.
○: not peeled even 200 times or more Δ: peeled 50 times or more and less than 200 times ×: peeled less than 50 times

(Evaluation of antireflection effect)
The loss of light amount when transmitting a light beam having a wavelength of 405 nm (= transmittance− (incident side surface reflectance + exit side surface reflectance)) was measured and evaluated according to the following criteria. The result is as shown in the column of “Effect (Loss of light quantity)”.
○: Less than 5% △: 5% or more, less than 10% ×: 10% or more

(Comprehensive evaluation)
From the above results, the samples (4), (8), and (12) as examples of the present invention have improved heat resistance against reflow treatment compared with other samples as comparative examples, and antireflection films. It was found that the occurrence of cracks and film peeling was prevented, and the reduction in light loss was prevented.

It is a schematic perspective view of the electronic device used by preferable embodiment of this invention. 1 is a schematic cross-sectional view enlarging a peripheral portion of an imaging device in an electronic apparatus used in a preferred embodiment of the present invention. It is a perspective view which shows roughly the external appearance of a lens array. It is a perspective view which shows schematic structure of a master and a submaster. It is drawing which shows schematic structure of a master, a submaster, and a subsubmaster. It is a figure for demonstrating the creation method of the molding surface by a ball end mill. It is drawing for demonstrating the manufacturing method of a lens array. It is a reaction diagram of a release agent using an alkoxysilane group as an example of a functional group capable of being hydrolyzed at the terminal and an OH group on the master surface. It is a top view which shows schematic structure of a large diameter submaster. It is a top view which shows schematic structure of a normal submaster. It is drawing for demonstrating a mode that a lens part is formed in the front and back both surfaces of a glass substrate using a large diameter submaster and a normal submaster. It is drawing for demonstrating the inconvenience at the time of using a large diameter submaster. It is drawing which shows the modification of a large diameter submaster. It is drawing for demonstrating schematically the manufacturing method of the electronic device in preferable embodiment of this invention. It is drawing for demonstrating the manufacturing method of a lens array. FIG. 16 is a view for explaining a manufacturing method subsequent to FIG. 15.

Explanation of symbols

9 Imaging lens (optical element)
91 Wafer lens (base material)
92 Antireflection film 911 First optical member 912 Second optical member

Claims (4)

A substrate formed of a resin material including at least one optical surface containing a curable resin;
An antireflection film made of an inorganic material formed on the optical surface of the substrate;
An optical element, wherein a surface of the optical surface of the substrate is substituted with fluorine. The optical element according to claim 1, wherein
The substrate is
A first optical member made of a material containing glass or a curable resin;
An optical element comprising a wafer lens made of a resin material containing a curable resin and having a second optical member bonded to the surface of the first optical member. Using a base material formed of a resin material including at least one optical surface containing a curable resin,
After fluorine-substituting the surface of the optical surface of the substrate,
An optical element manufacturing method, comprising: forming an antireflection film made of an inorganic material on the optical surface of the substrate. After placing the optical element as an imaging lens manufactured by the method for manufacturing an optical element according to claim 3 on a substrate together with an electronic component,
A method for manufacturing an electronic apparatus, comprising: subjecting the imaging lens, the electronic component, and the substrate to reflow processing, and mounting the imaging lens and the electronic component as an imaging module on the substrate.

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