JPWO2009057491A1 - Optical element manufacturing method and optical element - Google Patents

Abstract

In order to suppress fluctuations in optical characteristics due to the reflow process, the imaging apparatus 100 includes a lens 16 made of a thermosetting resin that is mounted on the substrate of the electronic device using the reflow process. When the refractive index is measured in the state of a plate-shaped molded product having a thickness of 3 mm, the lens 16 is formed under the condition that the refractive index distribution value X in the thickness direction of the plate-shaped molded product satisfies the following conditional expression. . X = {∫ | nd−n | × ω (n) dn} / {∫ω (n) dn} <1.3 × 10 −3 “nd” is the refractive index of the main peak in the d-line, “n” Represents an arbitrary refractive index in a range of nd ± 0.01, and “ω (n)” represents an intensity at a refractive index n.

Description

  The present invention relates to a method for manufacturing an optical element used for an imaging device mounted on a substrate of an electronic device using a reflow process, and an optical element.

  Conventionally, when an IC (Integrated Circuits) chip or other electronic component is mounted on a circuit board, a metal paste (for example, a solder paste) is previously applied (potted) to a predetermined position of the circuit board, and the electronic is placed at the position. A technology for manufacturing an electronic module at a low cost has been developed by a technique of subjecting the circuit board to a reflow process (heating process) with components mounted thereon and mounting the electronic component on the circuit board (for example, patents). Reference 1).

  And as one of such technologies, in a state where the electronic component on which the image sensor is mounted is fitted in a cylindrical socket (lens case), the socket and the electronic component are placed on the circuit board, There is a technique for manufacturing an imaging device by fitting an imaging lens in a socket after performing the solder reflow process as described above (see, for example, Patent Document 2).

  However, in the technique described in Patent Document 2, an electronic component is placed on a circuit board and mounted by reflow processing, and then an imaging lens is placed on the electronic component. It takes time and effort to divide the process into two steps. In addition, since it is necessary to fit the imaging lens into the socket in consideration of the thickness of the solder interposed between the electronic component and the circuit board, manufacturing errors in the inner peripheral portion of the socket and the outer peripheral portion of the imaging lens, etc. It will take. And it takes time and labor to reduce the productivity of the imaging apparatus.

  Therefore, there is a demand for a technique of simultaneously mounting an electronic component and an optical element on a substrate, and an optical element material that can cope with this reflow process is demanded.

In such a situation, the thermoplastic resin used as a conventional optical element has plasticity due to heat and it is difficult to make it compatible with the reflow treatment, so it is hardened by heat instead of the thermoplastic resin. In some cases, a thermosetting resin is used. However, it has been found that when a thermosetting resin is molded and the molded product is reflowed, the optical characteristics fluctuate for some reason and the performance as an imaging device may be hindered.
JP 2001-24320 A JP 2004-153855 A

  Therefore, the present inventors examined this problem, and found that the refractive index distribution fluctuated before and after the reflow treatment, and as a result, the optical characteristics fluctuated. Specifically, the present inventors first formed an optical element with a thermosetting resin, and measured the refractive index distribution in the “direction perpendicular to the optical axis direction” of the optical element. Was not seen. Therefore, a thermosetting resin is molded to produce a plate-shaped molded product having a thickness of about 3 mm, the refractive index distribution in the “thickness direction” (cross-sectional direction of the molded product) of the molded product is measured, and before and after the reflow treatment We observed changes in the refractive index profile.

  In the measurement of the refractive index distribution, a light beam having a predetermined wavelength was obliquely incident on the molding, and the refractive index obtained from the direction (position) of the emitted light beam, its distribution, and the intensity of the emitted light at that time were measured.

  Then, before the reflow process, the peak width of the refractive index distribution in the “thickness direction” is relatively wide (the area in the vicinity of the maximum intensity value is wide), or a plurality of refractive index values different in the “thickness direction”. It was proved that the peak (branch of the refractive index) occurred. Further, it was observed that the width of the refractive index distribution peak changed or the branched refractive index changed to a single peak after the reflow treatment. In other words, it was found that the reflow treatment caused a change in the refractive index distribution in the thickness direction, which caused variations in the optical characteristics of the optical element.

  Therefore, a main object of the present invention is to provide an optical element capable of suppressing a change in optical characteristics due to a reflow process and a method for manufacturing the optical element.

In order to solve the above problems, the method for manufacturing an optical element according to claim 1 is a method for manufacturing an optical element used in an imaging device mounted on a substrate of an electronic device using a reflow process. The optical element is made of a thermosetting resin, and the following conditional expression:
X = {∫ | nd−n | × ω (n) dn} / {∫ω (n) dn} <1.3 × 10 ⁻³
... (1)
However, X: of the plate-shaped molded product when the refractive index is measured in the state of a plate-shaped molded product having a thickness of 3 mm
Refractive index distribution value in the thickness direction nd: Refractive index of the main peak in the d line n: Arbitrary refractive index ω (n) in the range of nd ± 0.01: Conditions satisfying the intensity at the refractive index n Features.

  The optical element manufacturing method according to claim 2 is characterized in that in the invention according to claim 1, an annealing process is provided before the reflow process.

The optical element according to claim 3 is an optical element used in an imaging device mounted on a substrate of an electronic device using a reflow process, and the optical element is made of a thermosetting resin. The following conditional expression:
X = {∫ | nd−n | × ω (n) dn} / {∫ω (n) dn} <1.3 × 10 ⁻³
... (1)
However, X: When the refractive index is measured in the state of a plate-like molded product having a thickness of 3 mm,
Refractive index distribution value in the thickness direction nd: Refractive index of main peak in d line n: Arbitrary refractive index ω (n) in the range of nd ± 0.01: Conditions satisfying the intensity at refractive index n It is characterized by.

  In the present invention, it is formed under the conditions satisfying the above conditional expression, when a 3 mm thick plate-shaped molded product is molded using the same material as the resin used for molding the optical element. It means that the optical element is formed under the condition that the above conditional expression can be satisfied.

  The optical element according to claim 4 is characterized in that, in the invention according to claim 3, the optical element is annealed before the reflow treatment.

  The optical element according to claim 5 is characterized in that, in the invention according to claim 3 or 4, the thermosetting resin is an acrylic resin or an epoxy resin.

  According to the present invention, since the optical element is formed under the condition satisfying the conditional expression (1) when the plate-shaped molded article is formed, the change in the refractive index distribution is suppressed even when the reflow process is performed, and the reflow process is performed. Variations in optical characteristics can be suppressed.

It is a schematic perspective view of the imaging device used by preferable embodiment of this invention. 1 is an enlarged schematic cross-sectional view of a part of an imaging apparatus used in a preferred embodiment of the present invention. It is a refractive index distribution map which shows roughly the relationship between a refractive index and its intensity | strength. It is the schematic for demonstrating the refractive index distribution characteristic of the optical element used by preferable embodiment of this invention. It is drawing for demonstrating schematically the manufacturing method of the imaging device in preferable embodiment of this invention. It is a figure which shows schematically the fluctuation | variation of the optical characteristic of the lens by the presence or absence of an annealing process, and a reflow process. 1 is a drawing schematically showing a refractive index profile (relation between refractive index and intensity) of a sample 1; 5 is a drawing schematically showing a refractive index profile (relation between refractive index and intensity) of Sample 2. 4 is a drawing schematically showing a refractive index profile (relation between refractive index and intensity) of Sample 3. 4 is a drawing schematically showing a refractive index profile (relation between refractive index and intensity) of Sample 4. 2 is a drawing schematically showing a refractive index profile (relation between refractive index and intensity) of a sample 5; 3 is a drawing schematically showing a refractive index profile (relation between refractive index and intensity) of a sample 6; 3 is a drawing schematically showing a refractive index profile (relation between refractive index and intensity) of a sample 7; 2 is a drawing schematically showing a refractive index profile (relation between refractive index and intensity) of a sample 8; 2 is a drawing schematically showing a refractive index profile (relation between refractive index and intensity) of a sample 9;

Explanation of symbols

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

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

  As shown in FIG. 1, an imaging apparatus 100 as an electronic module has a circuit board 1 on which electronic components constituting an electronic circuit of a mobile information terminal device such as a mobile phone are mounted. Module 2 is mounted. The imaging module 2 is a small board mounting camera that combines a CCD image sensor and a lens. The imaging module 2 is provided in the cover case 3 in a completed state in which the circuit board 1 on which electronic components are mounted is incorporated in the cover case 3. An image to be imaged can be captured through the imaging aperture 4. In FIG. 1, illustration of electronic components other than the electronic components of the imaging module 2 is omitted. Further, the imaging module 2 may be a combination of a CMOS image sensor and a lens.

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

  On the upper surface of the CCD image sensor 11, a light receiving portion (not shown) in which a large number of pixels that perform photoelectric conversion are arranged in a grid pattern is formed, and an optical image is formed on the light receiving portion to store each pixel. The charged charges are output as an image signal. The sub-board 10 is mounted on the circuit board 1 by the conductive material 18, thereby fixing the sub-board 10 to the circuit board 1, and connecting electrodes (not shown) of the sub-board 10 and circuit electrodes on the upper surface of the circuit board 1. (Not shown) is electrically connected.

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

  The lens 16 is an example of an optical element for reflow processing, and is made of a thermosetting resin. As the thermosetting resin, for example, the types of resins listed below can be preferably used.

[Thermosetting resin]
The thermosetting resin is not particularly limited as long as it is a curable resin that is cured by heat treatment, but as the thermosetting resin, for example, the types of resins listed below can be preferably 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 or a butyl group, an alkenyl group such as a vinyl group or an allyl group, an aryl group such as a phenyl group or 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 differs in a 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, and 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 mass 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.

(acrylic resin)
Specific examples of the acrylic resin include, for example, an acrylic resin having a tricyclocyclodecane derivative (JP-A-7-26193 and JP-A-7-69985), NK ester DCP (tricyclodecane dimethanol, manufactured by Shin-Nakamura Chemical Co., Ltd. Dimethacrylate), NK ester A-DCP, manufactured by Shin-Nakamura Chemical, adamantyl (meth) acrylate (JP 2005-8527 A), NK ester IB, manufactured by Shin-Nakamura Chemical, NK ester A-IB, manufactured by Shin-Nakamura Chemical -Adamantanediol diacrylate, 1,3,5-adamantanetriol triacrylate, adamantyl (meth) acrylate (Japanese Patent Laid-Open No. 2005-8527) and the like.

  These acrylic resins may be polymerized independently. In that case, 0.01 to 5 parts by mass of the following polymerization initiator is used with respect to 100 parts by mass of the total amount of monomers. In order to increase the degree of crosslinking, the following (meth) acrylate may be used by mixing the following crosslinking monomer. In that case, it is desirable to mix and use a polymerization initiator in 60-5 mass% of a crosslinkable monomer with respect to 40-95 mass% of (meth) acrylate.

  Crosslinkable monomers include methyl (meth) acrylate, benzyl (meth) acrylate, phenyl (meth) acrylate, ethylene glycol (meth) acrylate, diethylene glycol (meth) acrylate, triethylene glycol (meth) acrylate, tetraethylene Glycol di (meth) acrylate, 2, -methyl-1,8-octanediol (meth) acrylate, 1,6-hexanediol di (meth) acrylate, neopentyldiol di (meth) acrylate, polyethylene glycol di (meth) Acrylate, ethylene oxide modified bisphenol A di (meth) acrylate, propylene oxide modified bisphenol A di (meth) acrylate, trimethylolpropane tri (meth) acrylate, ditrimethylol group Such Pantetora (meth) acrylate. These crosslinkable monomers can be used alone or in combination of two or more.

  The polymerization initiating means can be performed by using radical polymerization initiators such as various peroxides and azo compounds.

  The radical polymerization agent is not particularly limited, and known ones can be used. Typical examples include ketone peroxides, dialkyl peroxides, peroxyketals, peroxydicarbonates, hydroperoxides. , Peroxyesters, diacyl peroxides and the like. In addition, 2,2′-azobisisobutyronitrile, 2,2′-azobis (4-dimethylvaleronitrile), 2,2′-azobis (2-methylbutyronitrile), 1,1′-azobis ( And azo compounds such as cyclohexane-1-carbonitrile).

  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.

(Epoxy resin)
Examples of the epoxy compound include novolak phenol type epoxy resin, biphenyl type epoxy resin, dicyclopentadiene type epoxy resin, bisphenol F diglycidyl ether, bisphenol A diglycidyl ether, and 2,2′-bis (4-glycidyloxycyclohexyl). Propane, 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate, vinylcyclohexene 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, triglycidyl isocyanurate, monoallyl diglycidyl isocyanate Examples thereof include nurate and diallyl monoglycidyl isocyanurate.

  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.

  The lens 16 is preferably annealed in advance before being held by the lens case 15 (before being installed in the lens module 6). “Annealing treatment” means heat treatment or wet heat treatment at a temperature of 100 to 300 ° C. for 1 hour or more.

  Here, a normal lens used in a known imaging device or the lens 16 according to the present embodiment has a profile (refractive index distribution) as shown in FIGS. 3A to 3F in relation to the refractive index and its intensity. )have. In particular, the lens 16 according to the present embodiment is formed under a condition that satisfies the relationship of the conditional expression (1) in the refractive index distribution (see FIG. 4) showing the relationship between the refractive index and its intensity. Specifically, when the refractive index distribution in the thickness direction (optical axis direction) is measured by a refractive index measuring device (KPR-200, manufactured by Shimadzu Corporation), the lens 16 is in the state of a plate-shaped molded product having a thickness of 3 mm. The refractive index distribution value X (refractive index distribution or branch value) is formed under the same conditions as satisfying the following conditional expression (1).

X = {∫ | nd−n | × ω (n) dn} / {∫ω (n) dn} <1.3 × 10 ⁻³
... (1)
In formula (1), “nd” is the refractive index of the main peak in the d-line, “n” is the refractive index of the main peak in the range of nd ± 0.01, and “ω (n)” is the refractive index at the refractive index n. Represents strength.

  In the formula (1), when the refractive index distribution has two peaks as shown in FIG. 4 and the intensity of each peak is the same value, the low refractive index peak is set as the main peak. Moreover, Formula (1) is applied not only when the number of peaks in the refractive index distribution is two but also when the number of peaks is one or three or more.

  Next, a method for manufacturing the imaging device 100 will be described with reference to FIG.

  First, a thermosetting resin is injected and filled into a fixed mold and is thermoset to form a 3 mm thick plate-like molded product made of the thermosetting resin. At this time, the molded plate-shaped molded product is molded so as to satisfy the condition that satisfies the conditional expression (1). For example, heat treatment or wet heat treatment (annealing treatment) at a temperature of 100 to 300 ° C. for 1 hour or more can be mentioned. Thereafter, the lens 16 is formed under the same condition as the condition in which the plate-shaped molded product satisfies the conditional expression (1). At this time, as the optical material, the same material as that of the plate-like molded product is used, and the same annealing treatment is performed after the molding.

  When the manufacture of the lens 16 is completed, as shown in FIG. 5A, the substrate module 5 and the lens module 6 are assembled, and the lower end portion of the collar member 17 mounted in advance in the lens case 15 is on the upper surface of the sub-substrate 10. The mounting portion 15b of the lens case 15 is inserted into and fixed to the mounting hole 10a of the sub-board 10 until contact is made, and the imaging module 2 is formed.

  On the other hand, as shown in FIG. 5B, the imaging module 2 and other electronic components are placed at a predetermined mounting position of the circuit board 1 on which a conductive material 18 such as solder has been applied (potted) in advance. Then, as shown in FIG.5 (c), the circuit board 1 which mounted the imaging module 2 and other electronic components is transferred to a reflow furnace (not shown) with a belt conveyor etc., and the said circuit board 1 is 180-270 degreeC. Heat (reflow treatment) at about a temperature for about 1 hour. As a result, the conductive material 18 melts and the imaging module 2 is mounted on the circuit board 1 together with other electronic components.

  In the above embodiment, since the lens 16 is annealed in the same manner as the condition in which the refractive index distribution value X of the plate-shaped molded product satisfies the conditional expression (1) before the reflow treatment of the lens 16, Even when the imaging module 2 is mounted on the circuit board 1 together with the electronic components, the peak change in the refractive index distribution of the lens 16 can be suppressed and the fluctuation of the optical characteristics due to the reflow processing can be suppressed.

  FIG. 6 is a diagram schematically showing the presence or absence of annealing treatment and the change in optical characteristics of the lens due to reflow treatment. FIG. 6A is a diagram conceptually showing a refractive index distribution of a lens without annealing, and FIG. 6B is a refractive index after reflow processing of the lens without annealing shown in FIG. 6A. It is a figure which shows distribution conceptually. FIG. 6C conceptually shows the refractive index distribution of the lens with annealing treatment, and FIG. 6D shows the lens with annealing treatment shown in FIG. 6C after the reflow treatment. It is a figure which shows a refractive index distribution notionally.

  That is, when the lens 16 that is not annealed is reflowed as it is, the refractive index distribution of the lens changes from the state shown in FIG. 6A to the state shown in FIG. 6B, resulting in a large peak change, resulting in MTF. The value fluctuates greatly. On the other hand, when the lens 16 is annealed before the reflow process so as to satisfy the condition of the expression (1) as in this embodiment, the state shown in FIG. 6C is changed to the state shown in FIG. Peak changes in the refractive index distribution are suppressed, and as a result, fluctuations in the MTF value can be suppressed.

(1) Preparation of sample (1.1) Preparation of sample 1 Add 1 wt% of perbutyl O manufactured by NOF as a polymerization initiator to NK ester DCP (tricyclodecanedimethanol dimethacrylate) manufactured by Shin-Nakamura Chemical Co., Ltd. Curing was performed at 150 ° C. for 10 minutes to prepare a test piece (plate-shaped molded product) having a thickness of 3 mm, which was designated as “Sample 1”.
(1.2) Preparation of Sample 2 1 wt% of perfume O manufactured by Nippon Oil & Fats as a polymerization initiator was added to NK ester DCP (tricyclodecane dimethanol dimethacrylate) manufactured by Shin-Nakamura Chemical, and the mixture was cured at 150 ° C for 1 hour. Thus, a test piece (plate-shaped molded product) having a thickness of 3 mm was produced, and this was designated as “Sample 2”.
(1.3) Preparation of sample 3 1 wt% of perfume O manufactured by Nippon Oil & Fats as a polymerization initiator was added to NK ester DCP (tricyclodecane dimethanol dimethacrylate) manufactured by Shin-Nakamura Chemical, and the mixture was cured at 150 ° C. for 10 minutes. Thus, a test piece (plate-shaped molded product) having a thickness of 3 mm was produced. Thereafter, the test piece was further annealed (heated) at 270 ° C. for 1 hour, and this was designated as “Sample 3”.

(1.4) Preparation of Sample 4 A 2-alkyl-2-adamantyl (meth) acrylate prepared according to Japanese Patent Laid-Open No. 2002-193883 was cured at 130 ° C. for 10 minutes, and a test piece (plate-shaped molded product) having a thickness of 3 mm. And this was designated as “Sample 4”.
(1.5) Preparation of Sample 5 A 2-alkyl-2-adamantyl (meth) acrylate prepared according to Japanese Patent Laid-Open No. 2002-193883 was cured at 130 ° C. for 1 hour, and a test piece (plate-shaped molded product) having a thickness of 3 mm. And this was designated as “Sample 5”.
(1.6) Preparation of Sample 6 A 2-alkyl-2-adamantyl (meth) acrylate prepared according to Japanese Patent Laid-Open No. 2002-193883 was cured at 130 ° C. for 10 minutes, and a test piece (plate-shaped molded product) having a thickness of 3 mm. Was made. Thereafter, the test piece was further annealed (heated) at 270 ° C. for 1 hour, and this was designated as “Sample 6”.

(1.7) Production of Sample 7 As resin B, Daicel Ink Chemical Co., Ltd. acid anhydride EPICLON B-650 was mixed in each equivalent as Daicel Ink's aromatic-containing epoxy resin and curing agent, and the mixture Was cured at 160 ° C. for 10 minutes to prepare a test piece (plate-shaped molded product) having a thickness of 3 mm, which was designated as “Sample 7”.
(1.8) Preparation of Sample 8 As resin B, Daicel Ink Chemical Co., Ltd. acid anhydride EPICLON B-650 was mixed in an equivalent amount as Daicel Ink's aromatic-containing epoxy resin and a curing agent, and the mixture. Was cured at 160 ° C. for 1 hour to prepare a test piece (plate-shaped molded product) having a thickness of 3 mm, which was designated as “Sample 8”.
(1.9) Preparation of Sample 9 As resin B, Daicel Ink Chemical Co., Ltd. acid anhydride EPICLON B-650 is mixed in each equivalent as Daicel Ink's aromatic-containing epoxy resin and curing agent, and the mixture. Was cured at 160 ° C. for 10 minutes to prepare a test piece (plate-shaped molded product) having a thickness of 3 mm. Thereafter, the test piece was further annealed (heated) at 270 ° C. for 1 hour, and this was designated as “Sample 9”.

(1.10) Production of Lenses 1 to 9 “Lens 1” was produced in the same manner as the production method of Sample 1. Table 1 shows lens data of the lens 1. In addition, “lenses 2 to 9” were manufactured by the same method as that of Samples 2 to 9. Note that lens data of the lenses 2 to 9 is omitted.

2Y shown in Table 1 is the diagonal length of the solid-state imaging device. The aspherical shape is expressed by the following (Equation 1), where the vertex of the surface is the origin, the X axis is taken in the optical axis direction, and the height in the direction perpendicular to the optical axis is h. In the aspheric data, a power of 10 (for example, 2.5 × 10 ⁻² ) is expressed using E (for example, 2.5E−2).

However,
Ai: i-order aspherical coefficient R: radius of curvature K: conic coefficient

(2) Evaluation of sample (2.1) Refractive index distribution Using KPR-200 manufactured by Shimadzu Corporation as a refractive index measuring device, the refractive index of each sample 1-9 is measured, and the relationship between the refractive index and its strength is measured. The refractive index distribution shown was determined. The refractive index distributions of the samples 1 to 9 are shown in FIGS. 7 to 15, and the refractive index distribution values (values on the left side of equation (1), refractive index distributions or branch values) are shown in Table 2.

  7 shows the refractive index profile of sample 1 (relation between refractive index and intensity), FIG. 8 shows the refractive index profile of sample 2 (relation between refractive index and intensity), and FIG. 9 shows the refractive index profile of sample 3 (relationship between refractive index and intensity). 10 is a refractive index profile of sample 4 (relation between refractive index and intensity), FIG. 11 is a refractive index profile of sample 5 (relation between refractive index and intensity), and FIG. FIG. 13 shows the refractive index profile of the sample 6 (relation between refractive index and intensity), FIG. 13 shows the refractive index profile of the sample 7 (relation between refractive index and intensity), and FIG. FIG. 15 is a diagram schematically showing the refractive index profile (relation between the refractive index and the intensity) of the sample 9. Moreover, about the intensity | strength of the vertical axis | shaft, each maximum intensity | strength was set to 100, and it was set as the relative value with respect to this maximum intensity | strength.

(2.2) MTF fluctuation Using MATRIX plus manufactured by Nanotex Co., Ltd. as the MTF measuring instrument, the MTF value of each lens 1 to 9 at a spatial frequency of 78 lines / mm at the d-line was determined. Thereafter, the lenses 1 to 9 were put into a furnace at 270 ° C. and left for 60 minutes (reflow treatment). The similar MTF values were obtained again for each of the lenses 1 to 9 after the reflow processing, and the amount of change in the MTF values before and after the reflow processing was calculated. The calculation result is shown in the column of MTF fluctuation (relative value) in Table 2. In Table 2, the fluctuation amount of the lenses 2 and 3 is expressed as a relative value when the fluctuation amount of the lens 1 is 1.0, and the fluctuation amount of the lenses 5 and 6 is 1.0. The variation amount of the lenses 8 and 9 is represented by a relative value when the variation amount of the lens 7 is 1.0.

(3) Summary As shown in Table 2, the lenses 3, 6, and 9 annealed before the reflow treatment have significantly less MTF variation than the lenses 1, 2, 4, 5, 7, and 8, and before the reflow treatment. In the state, the refractive index distribution value of the test piece (plate-like molded product having a thickness of 3 mm) is less than 1.3 × 10 ⁻³ (the condition of the expression (1) is satisfied). It was found to be useful in suppressing

Claims (5)

A method of manufacturing an optical element used in an imaging device mounted using a reflow process on a substrate of an electronic device,
The said optical element is a product made from a thermosetting resin, and is formed on the conditions which satisfy | fill the following conditional expressions, The manufacturing method of the optical element characterized by the above-mentioned.
X = {∫ | nd−n | × ω (n) dn} / {∫ω (n) dn} <1.3 × 10 ⁻³
... (1)
However, X: of the plate-shaped molded product when the refractive index is measured in the state of a plate-shaped molded product having a thickness of 3 mm
Refractive index distribution value in the thickness direction nd: refractive index of main peak in d line n: arbitrary refractive index ω (n) in range of nd ± 0.01: intensity at refractive index n In the manufacturing method of the optical element of Claim 1,
An optical element manufacturing method comprising an annealing treatment step before the reflow treatment step. An optical element used in an imaging device mounted on a substrate of an electronic device using a reflow process,
The optical element is made of a thermosetting resin, and is formed under conditions that satisfy the following conditional expression.
X = {∫ | nd−n | × ω (n) dn} / {∫ω (n) dn} <1.3 × 10 ⁻³
... (1)
However, X: of the plate-shaped molded product when the refractive index is measured in the state of a plate-shaped molded product having a thickness of 3 mm
Refractive index distribution value in the thickness direction nd: refractive index of main peak in d line n: arbitrary refractive index ω (n) in range of nd ± 0.01: intensity at refractive index n The optical element according to claim 3,
An optical element that is annealed before the reflow treatment. In the optical element according to claim 3 or 4,
The optical element, wherein the thermosetting resin is an acrylic resin or an epoxy resin.