JP2010169708A - Composite optical element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a composite optical element capable of suppressing deformation of an optical surface at an interface between an optical base material and an energy-curable resin, and having high aberration compensation capability. <P>SOLUTION: The composite optical element has three-layer structure obtained by laminating two optical base materials 1 and 2 having positioning engagement parts 1a and 2a on the outer peripheral part of an optical effective diameter D<SB>1</SB>with the energy-curable resin 3. The engagement parts 1a and 2a are formed on the outer peripheral parts of the two optical base materials 1 and 2, respectively. Besides, the curing contraction ratio of the energy-curable resin 3 is within a range of 1 to 8%. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a composite optical element in which, for example, two optical substrates are laminated using an energy curable resin, and more particularly to a composite optical element using an energy curable resin having a high refractive index.

In recent years, there has been an increasing demand for miniaturization and high performance of an optical system used for an imaging module such as a camera, a video camera, a mobile phone with a camera, a video phone, or a door phone with a camera.
For this reason, in order to eliminate various aberrations in these optical systems, a large number of lenses have been used.

In particular, a composite optical element in which an energy curable resin is laminated on an optical substrate is a useful optical element because it can realize high aberration correction capability with a thin lens.
In particular, in a composite optical element having a three-layer structure in which an energy curable resin is laminated between two optical substrates, the composite optical element having a two-layer structure in which an energy curable resin is laminated on the optical substrate. On the other hand, it has a higher aberration correction capability and is therefore a very useful optical element.

  In such a composite optical element, transfer failure such as sink or distortion occurs in the resin layer due to curing shrinkage of the resin during molding. Also, molding defects such as a decrease in the shape accuracy of the optical surface of the resin layer are likely to occur.

  Furthermore, it was difficult to ensure the positional accuracy between the optical substrate and the molding die or between the optical substrate and the optical substrate. Then, examination of the curing conditions of the resin, the curing method, the shape of the optical base material and the molding die has been made.

For example, Patent Document 1 proposes a cemented lens in which an adhesive reservoir is provided on one or both of the outer peripheral portions of the lens cemented surface, and two lenses are laminated via the adhesive.
Patent Document 2 proposes a bonded lens in which a positioning flange that supports the other lens at a predetermined position and an adhesive discharge path for discharging an adhesive are provided at the lens peripheral end.

According to this bonded lens, positioning can be performed simply by fitting two lenses, and predetermined optical characteristics can be obtained without any influence of the amount of adhesive.
On the other hand, Patent Document 3 proposes a radiation curable resin composition containing at least one of a predetermined monomer and its oligomer as a resin composition for reducing curing shrinkage. The predetermined monomer is a monomer containing silica particles and a urethane bond or a hydroxyalkylene group. In patent document 3, at least one of a monomer and an oligomer has an acidic group, thereby realizing a resin composition having transparency, high adhesion, sufficient strength, and low curing shrinkage.

  Furthermore, in patent document 4, as a resin composition which reduces cure shrinkage, the inorganic component containing the silica particle which consists of a hydrolyzate of the oligomer of alkoxysilane, and the viscosity in 25 degreeC contain at least one of a monomer and an oligomer. A radiation curable resin composition having a thickness of 1,000 to 10,000 centipoise has been proposed.

Japanese Utility Model Publication No. 1-166601 Japanese Patent No. 3014808 JP 2005-36184 A JP 2004-169028 A

  However, Patent Document 1 and Patent Document 2 have the advantage that two lenses can be stacked regardless of the amount of the adhesive, but the curing shrinkage of the adhesive is not considered.

In other words, in Patent Document 1 and Patent Document 2, the shape of the optical surface at the interface between the lens and the adhesive may be deformed by the stress caused by the curing shrinkage of the adhesive.
In Patent Document 3 and Patent Document 4, optical characteristics such as a refractive index and an Abbe number related to aberration correction capability in an optical system are not considered as a resin composition for an optical element. For this reason, it is difficult to contribute to miniaturization and high performance of the optical system.

  The present invention has been made to solve such a problem, and provides a composite optical element capable of suppressing deformation of the optical surface at the interface between the optical base material and the energy curable resin and having high aberration correction capability. Objective.

In order to achieve the object, the invention according to claim 1
The composite optical element of the present invention is a composite optical element in which at least two optical base materials having a positioning fitting portion on the outer peripheral portion of the optical effective diameter are laminated using an energy curable resin.
The fitting portion is formed around each of the at least two optical base materials, and the curing shrinkage rate of the energy curable resin is 1% or more and 8% or less.

The composite optical element further includes a retention portion of the energy curable resin on the inner peripheral portion of the fitting portion and on the outer peripheral portion of the optical effective diameter.
The energy curable resin comprises 5% by mass to 30% by mass of inorganic particles (A) having an average particle diameter of 1 nm or more and 20 nm or less, a monofunctional compound (B) having one polymerizable functional group in the molecule, and The polyfunctional compound (C) having two or more polymerizable functional groups in the molecule and the polymerization initiator (D) are 0.05% by mass or more and 5% by mass or less, and the monofunctional compound (B) and the above The total mass ((B) + (C)) with the polyfunctional compound (C) is 70% by mass or more and 95% by mass or less, and the mass of the monofunctional compound (B) and the polyfunctional compound (C). A cured product of the composition having a ratio (B) / (C) of 0.5 or more and 100 or less.

  The energy curable resin comprises a monofunctional compound (B) having 5 to 30% by mass of inorganic particles (A) having an average particle size of 1 to 20 nm and one polymerizable functional group in the molecule. ), A polyfunctional compound (C) having two or more polymerizable functional groups in the molecule, a polymerization initiator (D) of 0.05% by mass to 5% by mass, a monofunctional compound (B) and a polyfunctional compound (B) The polymer (E) that can be dissolved in the functional compound (C) comprises 5% by mass or more and 30% by mass or less, and the total mass of the monofunctional compound (B) and the polyfunctional compound (C) ((B) + ( C)) is 50 mass% or more and 80 mass% or less, and mass ratio (B) / (C) of the monofunctional compound (B) and the polyfunctional compound (C) is 0.5 or more and 100 or less. It is a cured product of a composition.

  At least one of the monofunctional compound (B) and the polyfunctional compound (C) has at least one cyclic structure selected from an aromatic ring, a condensed polycyclic ring and an alicyclic ring.

  ADVANTAGE OF THE INVENTION According to this invention, the deformation | transformation of the optical surface of the interface of an optical base material and energy curable resin can be suppressed, and the composite type optical element with a high aberration correction capability can be obtained.

1 is a cross-sectional view of an optical substrate of Example 1. FIG. It is sectional drawing of the composite type optical element of the 3 layer structure which bonded together two optical base materials using energy curable resin. 3 is a cross-sectional view of an optical substrate of Example 2. FIG. It is sectional drawing of the composite type optical element of the 3 layer structure which bonded together two optical base materials using energy curable resin. 6 is a cross-sectional view of an optical substrate of Example 3. FIG. It is sectional drawing of the composite type optical element of the 3 layer structure which bonded together two optical base materials using energy curable resin.

First, an outline of the present invention will be described with reference to the drawings.
[Summary of Invention]
The outline of the present invention will be described with reference to FIG.

FIG. 2 shows a cross-sectional view of the composite optical element 10.
The composite optical element 10 has a three-layer structure in which two optical base materials (first optical base material 1 and second optical base material 2) are laminated using an energy curable resin 3. The composite optical element, the outer periphery of the optical effective diameter D ₁ of the both first optical substrate 1 and the second optical substrate 2, have the fitting portions 1a, 2a for positioning each other is doing.

  As the first and second optical bases 1 and 2, normal optical glass, optical resin, or transparent ceramics that can process the fitting portions 1a and 2a and the optical surface into desired shapes can be used.

Examples of the optical glass include quartz, BACD11 (HOYA), BSL7, BAL42, LAH53 (Ohara) and the like.
Optical resins include amorphous polyolefins such as ZEONEX (Nippon ZEON), ARTON (JSR), Apel (Mitsui Chemicals), acrylic resins such as Acrypet (Mitsubishi Rayon Le), and Delpet (Asahi Kasei). A certain Iupilon (Mitsubishi Engineer Plastics) can be mentioned.

Further, the fitting portion 1a, the outer peripheral portion of the inner and peripheral side and the optical effective diameter D ₁ of the 2a, preferably formed a retaining portion 9. This staying part 9 has a function of retaining excess energy curable resin 3 and preventing leakage to the outside.

Next, a method for manufacturing the composite optical element 10 will be described.
A required amount of energy curable resin 3 is discharged onto the optical surface on the bonding side of the first optical substrate 1. Next, from above the discharged energy curable resin 3, the second optical substrate 2 is lowered and brought into contact with the energy curable resin 3.

  Further, the second optical substrate 2 continues to descend until the fitting portions 1a and 2a formed on the first optical substrate 1 and the second optical substrate 2 are fitted to each other. Thus, the energy curable resin 3 is spread into a predetermined shape.

With the spread of the energy curable resin 3, extra energy curable resin 3 is retained in the retaining part 9 of the outer peripheral portion of the optical effective diameter D _1. This is because extra energy curable resin 3 is generated due to variations in the discharge amount and discharge position of energy curable resin 3. The staying portion 9 prevents leakage of the energy curable resin 3 to the outside.

  In addition, the fitting of the fitting portions 1a and 2a causes the energy curable resin 3 to spread into a predetermined shape, and the optical axes O− of the first optical base 1 and the second optical base 2. O matches and the alignment of both is completed.

  After fitting the first optical substrate 1 and the second optical substrate 2, the energy curable resin 3 is cured under predetermined curing conditions. Thus, the composite optical element 10 having a desired shape can be obtained.

  The shape of the staying portion 9 can be adjusted as appropriate depending on the optical surface of the composite optical element 10 or the shape of the energy curable resin 3, its discharge amount, or the size of variation in the discharge position. However, considering the need for miniaturization of products and optical systems, it is desirable to reduce the size of the retention portion 9 as much as possible.

For example, the size of the staying portion 9 is set in the range of about 4% to 12% of the volume of the energy curable resin 3 necessary for forming the optically effective diameter.
Thus, the shape of the uncured energy curable resin 3 is regulated by the fitting portions 1a and 2a. In this case, the shape change of the energy curable resin 3 accompanying the curing shrinkage may cause the first optical substrate 1 and the second optical substrate 2 to be deformed. Therefore, it is desirable to use the energy curable resin 3 having a small curing shrinkage rate.

  However, if the curing shrinkage rate of the energy curable resin 3 is too small, the curing reaction does not proceed. In this case, there is a possibility that the adhesion of the first optical substrate 1 or the second optical substrate 2 is lowered and peeled off. Furthermore, problems such as insufficient mechanical strength and insufficient durability occur. For this reason, the curing shrinkage rate of the energy curable resin 3 needs to be at least 1%.

On the other hand, in order to protect the 1st optical base material 1 and the 2nd optical base material 2 from a deformation | transformation, a cure shrinkage rate needs to be 8% or less.
The cure shrinkage is determined according to JIS K6901 (1999). This curing shrinkage (%) was obtained by measuring the density (d1) before curing and the density (d2) after curing of the energy curable resin 3 and obtaining the following formula.

Curing shrinkage rate (%) = {(density after curing (d2) −density before curing (d1)) / density before curing (d2)} × 100
Moreover, when it is desired to suppress the deformation of the first optical substrate 1 and the second optical substrate 2 to be small, it is preferable to form the staying portion 9 as described above.

  The energy curable resin 3 staying in the staying portion 9 absorbs the shape change caused by curing and shrinking of the uncured energy curable resin 3. In this way, the deformation of the first optical substrate 1 and the second optical substrate 2 can be suppressed to a small level.

In this case, the volume of the retention portion 9, to set the range of about 4% to 12% of the volume of the energy curable resin 3 required to form an optical effective diameter D ₁ is preferred. For this reason, it is important to adjust the curing conditions of the energy curable resin 3.

For example, if is less than 8% cure shrinkage, the energy curable resin 3 staying in the retention unit 9, it is possible to absorb the deformation of the energy curable resin 3 within the optical effective diameter D _1.
Thus, the stay part 9 has a function of preventing excess energy curable resin 3 from leaking to the outside. For this reason, the obtained composite optical element 10 can be accurately held in the lens frame.

  The inorganic particles (A) used for the energy curable resin 3 have an average particle diameter of 1 nm or more and 20 nm or less. Further, the inorganic particles (A) are substantially transparent inorganic particles in the use wavelength range of the composite optical element 10. Here, the average particle size is the central value of the particle size distribution in the particle size obtained by the dynamic light scattering method.

  Specific examples of the inorganic particles (A) include zirconium oxide, titanium oxide, tin oxide, antimony oxide, niobium oxide, cerium oxide, aluminum oxide, zinc oxide, tantalum oxide, and bismuth oxide. And particles of yttrium oxide, lanthanum oxide, ITO, ATO, and the like.

  Among these particles, zirconium oxide, titanium oxide, tin oxide, niobium oxide, zinc oxide, tantalum oxide, bismuth oxide, and yttrium oxide having a high refractive index and excellent transparency are preferable.

As the shape of the particles, a spherical shape, a polygonal shape, an indefinite shape, a flake shape, a fiber shape, a needle shape, a chain shape, and the like can be used, but a spherical shape is preferable in order to suppress light scattering by the particles.
Moreover, it is possible to adjust the ease of dispersion in the energy curable resin 3 by modifying the surface of the inorganic particles. For example, pretreatment with various functional group-containing polyisocyanates makes it possible to develop compatibility and chemical bonding with an acrylic resin.

  In addition, in the case of inorganic particles having a photocatalytic action such as titanium oxide particles, there is a possibility that the energy curable resin 3 may be adversely affected by decomposition over time. For this reason, it is possible to reduce the photocatalytic action by surface-modifying the particle surface with another inorganic component such as a silicon compound.

  The inorganic particles (A) are essential components for reducing the curing shrinkage of the composition and for increasing the refractive index of the resin. Content of an inorganic particle (A) is 5 to 30 mass%. When the content of the inorganic particles (A) is less than 5% by mass, curing shrinkage cannot be sufficiently reduced or the refractive index of the resin cannot be increased. Moreover, when there is more content of an inorganic particle (A) than 30 mass%, there exists a problem that light scattering increases.

  The monofunctional compound (B) used for the energy curable resin 3 is a compound having one polymerizable functional group in the molecule that can be polymerized into a polymer. Examples of the polymerizable functional group include a vinyl group, an acryloyl group, a methacryloyl group, an isocyanate group, an epoxy group, and an oxetane group.

In view of ease of curing of the energy curable resin 3 and the degree of freedom in selecting a compound, a vinyl group, an acryloyl group, and a methacryloyl group are more preferable.
Specific examples include methacrylic acid, acrylic acid, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, benzyl (meth) acrylate, phenyl (meth) acrylate, and nonyl. Phenyl (meth) acrylate, 2-hydroxypropyl methacrylate, 2-ethylhexyl (meth) acrylate, isobornyl (meth) acrylate, nonylphenyl (meth) acrylate, cyclohexyl (meth) acrylate, 2-phenyl-phenyl (meth) acrylate, 1 -Acryloyloxy-4-methoxynaphthalene, 10-acryloyloxy-10-methylbenzylanthrone, allylcarbazole, vinylbenzene, -vinyl anthracenecarboxylate, - such as methacryloyloxyethyl iso Sina sulfonate can be exemplified.

  In addition, (meth) acrylate means what contains at least one of acrylate and methacrylate. One or more components may be selected from these substances and mixed for use. These may be monomers or oligomers.

  Furthermore, organic compounds having not only a polymerizable functional group but also a condensed polycyclic ring such as an aromatic ring, naphthalene ring and anthracene ring in the molecule, a carbazole ring, a fluorene ring and the like have a high refractive index. preferable.

  The polyfunctional compound (C) used for the energy curable resin 3 is a compound having in the molecule two or more polymerizable functional groups that can be polymerized into a polymer. Examples of the polymerizable functional group include a vinyl group, an acryloyl group, a methacryloyl group, an isocyanate group, an epoxy group, and an oxetane group as in the case of the monofunctional compound (B).

More preferred are vinyl group, acryloyl group, and methacryloyl group from the viewpoint of easy curing of the energy curable resin 3 and the degree of freedom in selecting a compound.
Specific examples include dimethylol tricyclodecane dimethacrylate, trimethylolpropane tri (meth) acrylate, bisphenol A di (meth) acrylate, polyethylene glycol di (meth) acrylate, 9-fluorenyl acrylate, 9,9-bis. [4- (2-acryloyloxyethoxy) phenyl] fluorene, divinylbenzene and the like can be mentioned.

  The total mass of the monofunctional compound (B) and the polyfunctional compound (C) in the entire energy curable resin 3 is 70% by mass or more when the polymer (E) is not included in the energy curable resin 3. It is below mass%. Moreover, when a polymer (E) is included, it is 50 to 80 mass%.

  Moreover, mass ratio (B) / (C) of a monofunctional compound (B) and a polyfunctional compound (C) is 0.5 or more and 100 or less. By this mass ratio (B) / (C), the rate of the polymerization reaction of the energy curable resin 3 can be adjusted, and the degree of cure, strength, and heat resistance of the resulting cured product can be changed.

  The energy curable resin 3 needs to have an appropriate degree of curing, strength, heat resistance, and durability. In this case, if the degree of curing and heat resistance are too low, the strength cannot be obtained because it is in a soft state. Moreover, there is a possibility that the position accuracy of the shape of the optical surface and the first optical base material 1 and the second optical base material 2 cannot be maintained due to changes in temperature and humidity.

  Furthermore, if the degree of cure of the energy curable resin 3 is too high than necessary, stress tends to accumulate. Furthermore, problems such as poor durability, such as cracking of the first optical substrate 1 and second optical substrate 2 and deformation of the optical surface, occur due to temperature and humidity changes.

  In order to obtain a cured product having an appropriate degree of curing and heat resistance and good durability, it is an effective means to appropriately mix monofunctional compounds and polyfunctional compounds having different numbers of polymerizable functional groups. In this case, the mass ratio (B) / (C) between the monofunctional compound (B) and the polyfunctional compound (C) is an important index.

  In the monofunctional compound (B) having one polymerizable functional group in one molecule, the polymer chain of the cured product has a two-dimensional structure. This monofunctional compound (B) reduces the degree of cure, strength, and heat resistance of the cured product, but has the effect of reducing stress due to curing and enhancing durability.

  On the other hand, in the polyfunctional compound (C) having two or more polymerizable functional groups in one molecule, the polymer chain of the cured product has a three-dimensional structure. This polyfunctional compound (C) has the effect of increasing the degree of cure, strength, and heat resistance of the cured product, and deformation due to temperature change is also reduced.

  When the mass ratio (B) / (C) of the monofunctional compound (B) and the polyfunctional compound (C) is less than 0.5 as the energy curable resin 3, the stress due to curing becomes too high, Durability due to humidity changes may deteriorate. Moreover, when mass ratio (B) / (C) of a monofunctional compound (B) and a polyfunctional compound (C) is larger than 100, a hardening degree, intensity | strength, and heat resistance become low.

The polymerization initiator (D) used for the energy curable resin 3 can be either a thermal polymerization initiator or a photopolymerization initiator, but is preferably a photopolymerization initiator.
This photopolymerization initiator does not require a time-consuming process such as heating, and can be efficiently cured. In addition, the photopolymerization initiator can easily adjust the curing conditions, and the deformation of the optical surfaces of the first optical substrate 1 and the second optical substrate 2 accompanying the curing shrinkage can be minimized. In addition, when a composite optical element with another optical member is manufactured, it is not easily affected by a problem caused by heating.

  Furthermore, photopolymerization initiators specifically include 4-dimethylaminobenzoic acid, 4-dimethylaminobenzoic acid ester, alkoxyacetophenone, benzyldimethyl ketal, benzophenone and benzophenone derivatives, alkyl benzoylbenzoate, bis (4-dialkyl). Aminophenyl) ketone, benzyl and benzyl derivatives, benzoin and benzoin derivatives, benzoin alkyl ether, 2-hydroxy-2-methylpropiophenone, 1-hydroxycyclohexyl phenyl ketone, thioxanthone and thioxanthone derivatives, 2,4,6-trimethylbenzoyl And diphenylphosphine oxide.

These photopolymerization initiators can be used alone or in combination of two or more.
Of these photopolymerization initiators, it is sufficient to use acylphosphine oxide compounds such as 2,4,6-trimethylbenzoyldiphenylphosphine oxide and phenylbis (2,4,6-trimethylbenzoyl) -phosphine oxide. Is particularly preferable since it provides excellent curability and transparency of the cured product.

  The content of the polymerization initiator (D) in the entire energy curable resin 3 is preferably 0.05% by mass or more and 5% by mass or less. Even if it is less than 0.05% by mass, a material composition having sufficient curability cannot be obtained, resulting in a cured product having a low degree of curing. Moreover, when it exceeds 5 mass%, transparency of hardened | cured material will fall.

The polymer (E) used for the energy curable resin 3 is a polymer that dissolves in the monofunctional compound (B) and the polyfunctional compound (C), and is a polymer of various monomers.
Specific examples of the polymer (E) include a polymer obtained by polymerizing the same monomer as at least one of the monofunctional compound (B) and the polyfunctional compound (C), a copolymer, polystyrene, polycarbonate, polymethyl methacrylate, and the like. can give.

  The polymer (E) is a component added to reduce the curing shrinkage of the composition. The type and molecular weight of the polymer (E) are optical characteristics (refractive index, Abbe number, etc.) required for the energy curable resin 3, processability (viscosity, curing conditions, etc.), durability (strength, light resistance, environment resistance, etc.) ) Can be selected as appropriate.

  The content of the polymer (E) in the entire energy curable resin 3 is preferably 5% by mass or more and 30% by mass or less. If the content of the polymer (E) is less than 5% by mass, the effect of addition is small and the curing shrinkage rate cannot be sufficiently reduced. Moreover, when there is more content of a polymer (E) than 30 mass%, it will become high viscosity too much and workability will fall or adhesiveness will fall.

Next, adjustment of the composition of the energy curable resin 3 will be described with reference to Table 1.
(Adjustment of composition of energy curable resin 3)
Table 1 shows the composition of the energy curable resin 3 composition.

無機粒子（Ａ）として、平均粒径１５ｎｍの五酸化ニオブの微粒子を、単官能化合物（Ｂ）としてイソボニルメタクリレートと９，９−ビス［４−（２−アクリロイルオキシエトキシ）フェニル］フルオレンを、多官能化合物（Ｃ）としてジメチロールトリシクロデカンジアクリレートを、重合開始剤（Ｄ）として２−ヒドロキシ−２−メチル−１−フェニルプロパン−１−オンを用いた。表１には、各成分の配合比率が示されている。

As inorganic particles (A), fine particles of niobium pentoxide having an average particle diameter of 15 nm, isobornyl methacrylate and 9,9-bis [4- (2-acryloyloxyethoxy) phenyl] fluorene as monofunctional compounds (B), Dimethylol tricyclodecane diacrylate was used as the polyfunctional compound (C), and 2-hydroxy-2-methyl-1-phenylpropan-1-one was used as the polymerization initiator (D). Table 1 shows the blending ratio of each component.

After the monofunctional compound (B), polyfunctional compound (C) and polymerization initiator (D) are mixed, the mixture is put into a wet bead mill together with niobium pentoxide fine particles, and the bead diameter is 0 while maintaining the temperature at about 60 ° C. All components were uniformly mixed for 2 hours using 0.03 mm beads to obtain an energy curable resin composition.
(Preparation of measurement sample of energy curable resin 3)
The composition was molded into a size of 20 mm in diameter and 1 mm in thickness, irradiated with ultraviolet rays at a wavelength of 400 nm for 100 seconds at an illuminance of 100 mW / cm ² , and further heated and cured at 80 ° C. for 1 hour to obtain a measurement sample.

About the obtained measurement sample, refractive index nd, Abbe number νd, and curing shrinkage were determined by the following methods.
The results are shown in Table 1.
(1) Measurement of refractive index The refractive index of Fraunhofer's d-line (589.2 nm), C-line (656.3 nm), F-line (486.1 nm), and g-line of the composition is a precision refractometer KPR-200. It was measured using (Shimadzu Device Manufacturing). The measurement environment was 20 ° C. and 60% RH.
(2) Calculation of Abbe number νd When the refractive indexes of the Fraunhofer d-line, C-line, F-line, and g-line obtained by measurement are nd, nC, nF, and ng, respectively, the Abbe number νd is Calculated from the following formula.

νd = (nd−1) / (nF−nC)
(3) Curing shrinkage The curing shrinkage was determined according to JIS K6901.

The density (d1) of the composition before curing of the energy curable resin was determined using a specific gravity bottle according to JIS K2249.
Assuming that the capacity V ml of the specific gravity bottle and the weight G g of the composition, the density (d1) of the composition before curing was obtained by the following formula.

Density of composition before curing (d1) = capacity V / weight G
The density (b) of the composition after curing was determined from the difference in buoyancy between air and water. Mass m1 g in the air, mass m2 g in the water If the density of water is (d _H2O = 0.998), the density (d2) of the composition after curing was determined by the following formula.

Density of composition after curing (d2) = m1 · _dH2O / (m1−m2)
And hardening shrinkage rate (%) was calculated | required by the following formula.
Curing shrinkage rate (%) = (d2−d1) / d2 × 100
(Adjustment of energy curable resin composition)
Formulation Example 2 and Formulation Example 5 shown in Table 1 were mixed in the same manner as Formulation Example 1 to obtain an energy curable resin composition.
(Preparation of energy curable resin measurement sample)
Samples similar to those in Formulation Example 1 were prepared and subjected to the same evaluation.

The results are shown in Table 1.

Next, the composite optical element of this embodiment will be specifically described.

1 and 2 show the manufacturing process of the composite optical element 10 of the first embodiment.
The composite optical element 10 of the present embodiment is basically the same as that described in the outline of the invention described above, and a part thereof will be described.

  FIG. 1 is a cross-sectional view of two optical substrates 1 and 2 to be bonded, and FIG. 2 is a three-layer composite type in which two optical substrates 1 and 2 are bonded using an energy curable resin 3. 1 is a cross-sectional view of an optical element 10.

As shown in FIG. 1, the first optical substrate 1 has a biconcave lens shape. The second optical substrate 2 has a meniscus lens shape.
The first optical substrate 1 is made of an acrylic resin. The first optical substrate 1, and an optical surface 4 ₁ and the optical surface 5 _1. The second optical substrate 2 is made of polycarbonate. The second optical substrate 2, and an optical surface 4 ₂ and the optical surface 5 _2.

Further, the outer peripheral portions of the optical effective diameters D ₁ of both the first and second optical bases 1 and 2 are provided with fitting portions 1a and 2a for determining each other's position on the entire outer peripheral side. Is formed.
That is, the first optical substrate 1 has a plane ₆₁ perpendicular to the optical axis O-O to the outer periphery of the optical surface 4 ₁ of the concave. Further, on an outer peripheral portion has a convex fitting part 1a that projects from the substrate main body side of the plane _61.

The second optical substrate 2 has a flat 6 ₂ perpendicular to the optical axis O-O to the outer periphery of the convex optical surface 4 _2. The plane 6 ₂ are formed to correspond to the first plane 6 ₁ of the optical substrate 1. Further, the outer peripheral portion of the plane 6 _2, and a fitting portion 2a for saving stepwise from the plane 6 ₂ to the substrate main body. The fitting portion 2 a is formed corresponding to the fitting portion 1 a of the first optical base material 1.

Next, a method for manufacturing the composite optical element 10 of this embodiment will be described.
As shown in FIG. 1, the second optical substrate 2 is separated upward from the first optical substrate 1.
In this state, the first upper optical surface 4 ₁ of the optical substrate 1 and the required amount of discharge energy curable resin 3 in "Formulation Example 1" of Table 1. Next, the second optical base material 2 is lowered and approached from above the discharged energy curable resin 3.

  Then, as shown in FIG. 2, the second optical substrate 2 is fitted until the fitting portions 1a and 2a formed on the first optical substrate 1 and the second optical substrate 2 are fitted to each other. Continue descending approach. Thus, the energy curable resin 3 is spread into a predetermined shape.

With the spread of the energy curable resin 3, extra energy curable resin 3 is retained in the retaining part 9 formed on the outer periphery of the optical effective diameter D _1. This is because variations occur in the discharge amount and discharge position of the energy curable resin 3. Thus, the staying part 9 prevents the energy curable resin 3 from leaking outside.

Moreover, the optical axis OO of the 1st optical base material 1 and the 2nd optical base material 2 corresponds by the fitting of this fitting part 1a, 2a, and both alignment is completed.
After fitting the first optical substrate 1 and the second optical substrate 2, the energy curable resin 3 is cured under predetermined curing conditions.

In this example, an ultraviolet curable resin was used as the energy curable resin 3. The energy curable resin 3 was cured by irradiating ultraviolet rays at a wavelength of 405 nm with an illuminance of 100 mW / cm ² for 100 seconds.

Thus, a composite optical element 10 having a desired shape was obtained.
Generally, the energy curable resin 3 cures and shrinks as it cures, and sink marks 3a corresponding to the cure shrinkage rate are formed on the outer periphery.

Here, in this example, the energy curable resin 3 having a sufficiently low curing shrinkage was used. That is, in this example, as described above, the energy curable resin 3 having a curing shrinkage rate of 1% or more and 8% or less was used. For this reason, the optical surfaces 4 ₁ and 4 ₂ of the first optical substrate 1 and the second optical substrate 2 did not deform so much as to affect the quality.

  In addition, although the present Example demonstrated the case where two optical base materials, the 1st optical base material 1 and the 2nd optical base material 2, were laminated | stacked, it is not restricted to this. For example, the present invention can also be applied when three or more optical substrates are laminated. This also applies to Example 2 and Example 3 described later.

According to the present embodiment, the energy curable resin 3 having a sufficiently low curing shrinkage rate is used, and the energy curable resin 3 staying in the staying portion 9 is deformed as the resin is cured. The deformation of the optical surfaces 4 ₁ and 4 ₂ at the interface between the optical substrates 1 and 2 and the energy curable resin 3 can be suppressed to be small.

3 and 4 show a manufacturing process of the composite optical element 20 according to the second embodiment.
FIG. 3 is a cross-sectional view of the two optical base materials 11 and 12 to be bonded together, and FIG. 4 is a three-layer composite type in which the two optical base materials 11 and 12 are bonded together using an energy curable resin 13. 2 is a cross-sectional view of an optical element 20. FIG.

As shown in FIG. 3, the first optical substrate 11 has a biconcave lens shape. Further, the second optical substrate 12 has a meniscus lens shape.
The first optical substrate 11 is made of an acrylic resin. The first optical substrate 11, and an optical surface 14 ₁ and the optical surface 15 _1. The second optical substrate 12 is made of polycarbonate. The second optical substrate 12, and an optical surface 14 ₂ and the optical surface 15 _2.

Further, the outer peripheral portion of both of the optical effective diameter D ₂ of the first and second optical substrates 11 and 12, the fitting portion 11a for positioning each other, 12a is the entire outer peripheral side of the respective Is formed.
That is, the first optical substrate 11 has a flat 16 ₁ orthogonal to the optical axis O-O to the outer periphery of the optical surface 14 ₁ of the concave. Further, on the outer peripheral portion of the plane 16 _1, the grooves 18 are formed. The groove 18 is formed so as to retreat the substrate main body than the plane 16 _1.

Further, a fitting portion 11 a is formed on the outer peripheral portion of the groove 18. The fitting portion 11a is formed in a convex shape so as to protrude from the substrate main body than the plane 16 _1.
The second optical substrate 12 has a flat 16 ₂ orthogonal to the optical axis O-O to the outer periphery of the convex optical surface 14 _2. This plane 16 ₂ is formed to correspond to the plane 16 ₁ and the groove 18 of the first optical substrate 11.

Furthermore, the fitting part 12a is formed in the outer peripheral part. The fitting portion 12a is formed in a stepped shape to retreat from the plane 16 ₂ on the substrate main body. The fitting portion 12 a is formed corresponding to the fitting portion 11 a of the first optical base material 11.

As in Example 1, acrylic resin was used as the first optical substrate 11 and polycarbonate was used as the second optical substrate 12.
Next, a method for manufacturing the composite optical element 20 of this example will be described.

As shown in FIG. 3, the second optical substrate 12 is separated upward from the first optical substrate 11. In this state, a required amount of the energy curable resin 13 made of the composition of “Prescription Example 3” in Table 1 is discharged onto the optical surface 141 of the _first optical substrate 11. Next, the second optical base material 12 is lowered and approached from above the discharged energy curable resin 13.

  And as shown in FIG. 4, until the fitting parts 11a and 12a formed in each of the 1st optical base material 11 and the 2nd optical base material 12 fit each other, the 2nd optical base material 12 Continue descending approach. Thus, the energy curable resin 13 is spread into a predetermined shape.

With the spread of the energy curable resin 13, extra energy curable resin 13 is retained in the retaining part 19 formed on the outer periphery of the optical effective diameter D _2. Thus, the staying portion 19 prevents the energy curable resin 13 from leaking to the outside.

In the present embodiment, the staying portion 19 is formed larger than the staying portion 9 of the first embodiment by the groove 18 of the first optical base material 11.
Further, by fitting the fitting portions 11a and 12a, the optical axes OO of the first optical base material 11 and the second optical base material 12 coincide with each other, and the alignment of both is completed.

After fitting the first optical base material 11 and the second optical base material 12, the energy curable resin 13 is cured under predetermined curing conditions.
In this example, the energy curable resin 13 was cured by irradiating ultraviolet rays at a wavelength of 405 nm with an illuminance of 100 mW / cm ² for 100 seconds.

The energy curable resin 13 cures and shrinks with curing, and sink marks 13a corresponding to the curing shrinkage rate are formed on the outer peripheral portion. However, the curing shrinkage rate of the energy curable resin 13 is sufficiently low. Moreover, the energy curable resin 13 staying in the staying portion 19 is deformed as it hardens. Therefore, no stress is generated on the optical surfaces 14 ₁ and 14 ₂ of the first and second optical base materials 11 and 12.

Thus, a composite optical element 20 having a desired shape as shown in FIG. 4 was obtained.
According to the present embodiment, the energy curable resin 13 having a low curing shrinkage rate is used, and the energy curable resin 13 staying in the staying portion 19 is deformed, whereby the first and second optical base materials 11 and 12 are used. The deformation of the optical surfaces 14 ₁ and 14 ₂ at the interface between the curable resin 13 and the energy curable resin 13 can be made smaller than that in the first embodiment.

5 and 6 show the manufacturing process of the composite optical element 30 of the third embodiment.
FIG. 5 is a cross-sectional view of the two optical base materials 21 and 22 to be bonded together, and FIG. 6 is a three-layer composite type in which the two optical base materials 21 and 22 are bonded together using an energy curable resin 23. 2 is a cross-sectional view of an optical element 30. FIG.

As shown in FIG. 5, the first optical substrate 21 has a meniscus lens shape. The second optical substrate 22 has a biconvex lens shape.
The first optical substrate 21 is made of ZEONEX E48R (Nippon Zeon). The first optical substrate 21 has an optical surface 24 ₁ and an optical surface 25 ₁ .

Moreover, the 2nd optical base material 22 consists of optical glass S-LAH59 (Ohara). The second optical substrate 22 has an optical surface 24 ₂ and an optical surface 25 ₂ .
Further, the outer peripheral portion of both of the optical effective diameter D ₃ of the first and second optical substrates 21 and 22, the fitting portion 21a for positioning each other, 22a is the entire outer peripheral side of the respective Is formed.

That is, the first optical substrate 21 has a flat 26 ₁ orthogonal to the optical axis O-O to the outer periphery of the optical surface 24 ₁ of the concave. Further, the outer peripheral portion of the plane 26 _1, the grooves 28 to retract from the plane 26 ₁ on the substrate main body side. Further, the outer peripheral portion of the groove 28, the convex fitting portion 21a which protrudes from the substrate main body side of the plane 26 ₁ is formed.

The second optical substrate 22 has a flat fitting portion 22a perpendicular to the optical axis O-O to the outer periphery of the convex optical surface 24 _2. The fitting portion 22a is formed corresponding to the fitting portion 21a of the first optical base material 21 and the like.

Next, a method for manufacturing the composite optical element 30 of this embodiment will be described.
As shown in FIG. 5, the second optical substrate 22 is separated upward from the first optical substrate 21. In this state, on the optical surface 24 ₁ of the second optical substrate 21, it is required discharge amount of the energy curable resin 23 consisting of the composition of the "formulation Example 5" in Table 1. Next, the second optical base material 22 is lowered and approached from above the discharged energy curable resin 23.

  Then, as shown in FIG. 6, the second optical base 22 is fitted until the fitting portions 21a and 22a formed on the first optical base 21 and the second optical base 22 are fitted to each other. Continue descending approach. Thus, the energy curable resin 23 is spread into a predetermined shape.

Along with the spreading of the energy curable resin 23, excess energy curable resin 23 is retained in a retention portion 29 formed on the outer peripheral portion of the academic effective diameter D ₃ . Thus, the staying portion 29 prevents excess energy curable resin 23 from leaking to the outside.

The stay part 29 is formed larger than the stay part 9 of the first embodiment by the groove 28 of the first optical base 21.
Moreover, the optical axes OO of the 1st optical base material 21 and the 2nd optical base material 22 correspond by the fitting of these fitting parts 21a and 22a, and both are positioned.

Thereafter, the energy curable resin 23 is cured by irradiating ultraviolet rays at a wavelength of 405 nm at an illuminance of 100 mW / cm ² for 100 seconds.
The energy curable resin 23 cures and shrinks with curing, but its curing shrinkage rate is sufficiently low. Moreover, the energy curable resin 23 staying in the staying portion 29 is deformed with hardening. Therefore, no stress is generated on the optical surfaces 24 ₁ and 24 ₂ of the first and second optical base materials 21 and 22.

Thus, a composite optical element 30 having a desired shape as shown in FIG. 6 was obtained.
According to the present embodiment, the energy curable resin 23 having a low curing shrinkage rate is used, and the energy curable resin 23 staying in the staying portion 29 is deformed, so that the first optical base material 21 and the second optical base material 21 are deformed. The deformation of the optical surfaces 24 ₁ and 24 ₂ at the interface between the base material 22 and the energy curable resin 23 could be suppressed to a small level.

DESCRIPTION OF SYMBOLS 1 1st optical base material 1a Fitting part 2 2nd optical base material 2a Fitting part 3 Energy curable resin 3a Sink 4 ₁ Optical surface 4 ₂ Optical surface 5 ₁ Optical surface 5 ₂ Optical surface 6 ₁ Plane 6 ₂ Plane 9 Staying portion 10 Composite optical element 11 First optical base material 11a Fitting portion 12 Second optical base material 12a Fitting portion 13 Energy curable resin 13a Sink 14 ₁ Optical surface 14 ₂ Optical surface 15 ₁ Optical surface 15 ₂ optical surface 16 ₁ plane 16 ₂ plane 18 groove 19 staying part 20 composite type optical element 21 1st optical base material 21a fitting part 22 2nd optical base material 22a fitting part 23 energy curable resin 24 ₁ optics Surface 24 ₂ Optical surface 25 ₁ Optical surface 25 ₂ Optical surface 26 ₁ Plane 28 Groove 29 Retaining part 30 Composite optical element D1 Optical effective diameter D2 Optical effective diameter D3 Optical effective diameter

Claims (5)

In a composite optical element in which at least two optical base materials having positioning fitting portions on the outer periphery of the optical effective diameter are laminated using an energy curable resin,
The composite optical element, wherein the fitting portion is formed around each of the at least two optical base materials, and the curing shrinkage rate of the energy curable resin is 1% or more and 8% or less. The composite optical element according to claim 1,
The composite-type optical element characterized by having a staying part of the energy curable resin on the inner peripheral part of the fitting part and on the outer peripheral part of the optical effective diameter. The composite optical element according to claim 1 or 2,
The energy curable resin comprises 5% by mass to 30% by mass of inorganic particles (A) having an average particle diameter of 1 nm or more and 20 nm or less, a monofunctional compound (B) having one polymerizable functional group in the molecule, and The polyfunctional compound (C) having two or more polymerizable functional groups in the molecule and the polymerization initiator (D) are 0.05% by mass or more and 5% by mass or less, and the monofunctional compound (B) and the above The total mass ((B) + (C)) with the polyfunctional compound (C) is 70% by mass or more and 95% by mass or less, and the mass of the monofunctional compound (B) and the polyfunctional compound (C). A composite optical element, characterized in that it is a cured product of a composition having a ratio (B) / (C) of 0.5 or more and 100 or less. The composite optical element according to claim 1 or 2,
The energy curable resin comprises 5% by mass to 30% by mass of inorganic particles (A) having an average particle diameter of 1 nm or more and 20 nm or less, a monofunctional compound (B) having one polymerizable functional group in the molecule, and A polyfunctional compound (C) having two or more polymerizable functional groups in the molecule, a polymerization initiator (D) of 0.05% by mass to 5% by mass, a monofunctional compound (B) and a polyfunctional compound The polymer (E) that can be dissolved in (C) comprises 5% by mass or more and 30% by mass or less, and the total mass ((B) + (C) of the monofunctional compound (B) and the polyfunctional compound (C). ) Is 50 mass% or more and 80 mass% or less, and the mass ratio (B) / (C) of the monofunctional compound (B) and the polyfunctional compound (C) is 0.5 or more and 100 or less. A composite optical element, which is a cured product of a product. The composite optical element according to claim 3 or 4,
At least one of the monofunctional compound (B) and the polyfunctional compound (C) has at least one cyclic structure selected from an aromatic ring, a condensed polycyclic ring and an alicyclic ring. element.

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