Optical element, method for manufacturing optical element, resin composition, optical device, and imaging device

Abstract

To provide an optical element which has a low hygroscopic expansion coefficient and has optical performance hardly changing even under a high humidity environment, and a method for manufacturing the same.SOLUTION: An optical element 10 comprises a cured product 2. The cured product has a mono- or bifunctional first (meth)acrylate compound with an alicyclic skeleton represented by general formula (1) or (2), and a second bifunctional (meth)acrylate compound with a bisphenol skeleton represented by general formula (3).SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to an optical element, a method for manufacturing an optical element, a resin composition, an optical instrument, and an imaging device. [Background technology]

[0002] One type of optical element known is a lens in which a cured resin is provided on a transparent substrate such as a glass lens. Such lenses are manufactured using a molding die by providing a resin composition between the substrate and the molding die, polymerizing or copolymerizing the resin composition to form a cured product of the desired shape on the surface of the substrate. Lenses manufactured by this method are called replica elements. Because replica elements can be easily formed into the desired surface shape, they are effective for use as aspherical lenses or Fresnel lenses. An aspherical lens is a general term for a lens whose curvature changes continuously from the center to the periphery. Patent Document 1 discloses a resin composition having a bisphenol skeleton that can be used in replica elements, and a cured product thereof. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2004-346225 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the cured product disclosed in Patent Document 1 has a high coefficient of swelling due to its water absorption, and therefore has the problem that its optical performance is easily affected in a high humidity environment. [Means for solving the problem]

[0005] A first aspect for solving the above problem is a method for producing a polymerizable composition comprising a first monofunctional or bifunctional (meth)acrylate compound having an alicyclic skeleton represented by the following general formula (1) or (2) and a second bifunctional (meth)acrylate compound having a bisphenol skeleton represented by the following general formula (3): The resin composition containing cured product and a transparent substrate on which the cured product is provided. Equipped with the content ratio of the first (meth)acrylate compound and the second (meth)acrylate compound in the cured product is in the range of 90% by mass or more and 99.5% by mass or less, a content ratio of the first (meth)acrylate compound to the sum of the first (meth)acrylate compound and the second (meth)acrylate compound in the cured product is in the range of 50% by mass or more and 90% by mass or less; the ratio of the maximum thickness d2 of the cured product to the minimum thickness d1 is greater than 1 and less than or equal to 30; The minimum thickness d1 is 300 μm or less, and the maximum thickness d2 is in the range of 10 μm or more and 1000 μm or less. The optical element is characterized by the above.

[0006] [ka]

[0007] [ka]

[0008] [ka] (In the above general formula (3), R1 and R2 represent a hydrogen atom or a methyl group, and m+n represents a numerical value.)

[0009] The second aspect of the present invention for solving the above problems is a method for manufacturing a polymerizable composition comprising a transparent substrate and a polymerizable compound represented by the following general formula (1) or general formula ( 2) Polymerizable functional group of monofunctional or bifunctional (meth)acrylate having an alicyclic skeleton represented by the formula The first material has a group and a bifunctional ( A resin composition having a second material having a polymerizable functional group of methacrylate and a polymerization initiator. a preparing step of preparing the resin composition; an installing step of providing the resin composition on the transparent substrate; a curing step of curing the resin composition to form a cured product; a step of obtaining the optical element through the curing step; The method for producing an optical element is characterized by comprising the steps of:

[0010] [ka]

[0011] [ka]

[0012] [ka] (In the above general formula (3), R1 and R2 represent a hydrogen atom or a methyl group, and m+n represents a numerical value.) [Effects of the Invention]

[0018] According to the above aspect, it is possible to provide an optical element having a low water swelling coefficient and optical performance that is less likely to change even in a high-humidity environment, a method for manufacturing the same, a resin composition for use in the optical element, and an optical device and an imaging device using the optical element. [Brief explanation of the drawings]

[0019] [Figure 1] FIG. 1 is a schematic diagram illustrating an optical element according to a first embodiment. [Figure 2] 2A to 2C are schematic diagrams illustrating a method for manufacturing an optical element according to the first embodiment. [Figure 3] FIG. 10 is a schematic diagram showing an imaging device according to a third embodiment. [Figure 4] FIG. 2 is a schematic diagram showing the thickness of a cured product in an optical element according to an example. DETAILED DESCRIPTION OF THE INVENTION

[0020] Hereinafter, embodiments of the present disclosure will be described.

[0021] (First embodiment) [Optical elements] FIG. 1 is a schematic diagram showing an optical element according to a first embodiment, and is a side cross-sectional view of an optical element 10 cut in the lamination direction along a straight line passing through the element center O of the optical element.

[0022] The optical element 10 has a transparent substrate 1 and a cured product 2. The optical element 10 is a type of optical element called a replica lens, in which the cured product is provided on the transparent substrate 1.

[0023] (Transparent base material) The transparent substrate 1 has a first surface 1A and a second surface 1B, which are optical surfaces. The first surface 1A of the transparent substrate is either a light incident surface or a light exit surface, and the second surface 1B of the transparent substrate is the other of the light incident surface and the light exit surface.

[0024] The transparent substrate 1 can be made of a transparent resin or transparent glass. In this specification, "transparent" means that the transmittance of light in the wavelength range of 400 nm to 780 nm is 10% or more. The transparent substrate 1 is preferably made of glass, and examples of materials that can be used include common optical glasses such as silicate glass, borosilicate glass, and phosphate glass, as well as quartz glass and glass ceramics.

[0025] In Figure 1, the first surface 1A is concave spherical and the second surface 1B is convex spherical, but the shape of the transparent substrate 1 is not particularly limited. The shape of the surface of the transparent substrate 1 that comes into contact with the cured product 2 can be selected from concave spherical, convex spherical, axisymmetric aspherical, flat, etc., depending on the desired characteristics. The transparent substrate 1 is preferably circular when viewed from above on the paper surface of Figure 1. This is because this improves assembly accuracy when the optical element 10 is used as a lens in an optical system, which will be described later.

[0026] (cured product) The cured product 2 is provided in close contact with the first surface 1A of the transparent substrate. The cured product 2 is a cured product of a resin obtained by polymerizing or copolymerizing a resin composition 2a. The cured product 2 contains a monofunctional or bifunctional first (meth)acrylate compound having an alicyclic skeleton represented by the following general formula (1) or general formula (2). The cured product 2 also contains a bifunctional second (meth)acrylate compound having a bisphenol skeleton represented by the following general formula (3).

[0027] [ka]

[0028] [ka]

[0029] [ka] (In the above general formula (3), R1 and R2 represent a hydrogen atom or a methyl group, and m+n represents a numerical value.)

[0030] Resin composition 2a includes a first material and a second material. The first material includes at least one of a compound (monomer) having a structure with an alicyclic skeleton represented by the following general formula (1) or general formula (2) and a polymer (polymer or oligomer) thereof, and a polymerizable functional group of a monofunctional or difunctional (meth)acrylate. This first material is a precursor of the first (meth)acrylate compound.

[0031] [ka]

[0032] [ka]

[0033] The alicyclic skeleton has the effect of increasing the Abbe number of the cured product 2. Furthermore, due to the bulky structure of the alicyclic skeleton, it reduces cure shrinkage when the resin composition 2a is polymerized or copolymerized to obtain the cured product 2, thereby improving moldability. Furthermore, due to its bulky structure, it has the effect of increasing the glass transition temperature Tg. Furthermore, due to its rigid structure, it has the effect of reducing the water absorption expansion coefficient of the cured product 2. Examples of structures having an alicyclic skeleton include a tricyclodecane skeleton represented by the above general formula (1) and an isobornyl group represented by the above general formula (2). Monomers having a tricyclodecane skeleton are superior in terms of small cure shrinkage. An isobornyl group is superior in terms of low water absorption expansion coefficient. Furthermore, a polymerizable functional group of a monofunctional (meth)acrylate is more preferable because it has a lower water absorption expansion coefficient than a polymerizable functional group of a difunctional (meth)acrylate.

[0034] Commercially available materials for the first material described above include, for example, materials having a monofunctional polymerizable functional group such as FA-513M (dicyclopentamethacrylate) from the Fancryl series manufactured by Showa Denko Materials Inc., IB (isobornyl methacrylate) and A-IB (isobornyl acrylate) manufactured by Shin-Nakamura Chemical Co., Ltd., and IB-X (isobornyl methacrylate) and IB-AX (isobornyl acrylate) manufactured by Kyoeisha Chemical Co., Ltd. Furthermore, materials having a bifunctional polymerizable functional group such as DCP (dimethylol-tricyclodecane dimethacrylate) and A-DCP (dimethylol-tricyclodecane dimethacrylate) manufactured by Shin-Nakamura Chemical Co., Ltd., and DCP-M (dimethylol-tricyclodecane dimethacrylate) and DCP-A (dimethylol-tricyclodecane dimethacrylate) manufactured by Kyoeisha Chemical Co., Ltd. The first material may be of only one type, but two or more types may be used in combination depending on the amount of hardening collected during molding of the cured product 2, the coefficient of water absorption expansion, optical properties, and the like.

[0035] The second material has at least one of a compound having a bisphenol skeleton represented by the following general formula (3) and a polymer thereof, and a difunctional (meth)acrylate polymerizable functional group. This second material is a precursor of the second (meth)acrylate compound.

[0036] [ka] (In the above general formula (3), R1 and R2 represent a hydrogen atom or a methyl group, and m+n represents a numerical value.)

[0037] The polymerizable functional group of the bifunctional (meth)acrylate of the second material bonds with the polymerizable functional group of the monofunctional or bifunctional (meth)acrylate of the first material through a polymerization reaction. The bisphenol skeleton has the effect of increasing the flexibility of the resin composition 2a and the cured product 2. This makes it possible to accurately transfer the shape of the mold when molding the cured product 2 using a molding die. Bisphenol is a general term for compounds containing two hydroxyphenyl groups, but in this specification, the bisphenol skeleton is synonymous with diphenylmethane. Diphenylmethane is a type of aromatic hydrocarbon and has a structure in which two hydrogen atoms in methane are replaced by phenyl atoms.

[0038] Commercially available second materials include, for example, the bisphenol A EO adduct dimethacrylate series manufactured by Shin-Nakamura Chemical Co., Ltd., including BPE-80N (m + n = 2.3), BPE-100 (m + n = 2.6), BPE-200 (m + n = 4), BPE-300 (m + n = 7), and BPE-500 (m + n = 10), and the bisphenol A EO adduct diacrylate series including ABE-300 (m + n = 3), A-BPE-4 (m + n = 4), A-BPE-10 (m + n = 10), and A-BPP-3 (m + n = 3). While a single type of compound (monomer) having a bisphenol skeleton and its polymer may be used, two or more types may be used in combination depending on the transfer accuracy, curing yield, water absorption expansion coefficient, optical properties, etc., during molding of the cured product 2.

[0039] The content ratio of the first material and the second material in the resin composition 2a is preferably 90% by mass or more and 99.5% by mass or less. That is, the content ratio of the first (meth)acrylate compound and the second (meth)acrylate compound in the cured product 2 is preferably in the range of 90% by mass or more and 99.5% by mass or less. This is to ensure high transfer accuracy of the cured product 2 and an excellent coefficient of water absorption and expansion.

[0040] The content ratio of the first material in the resin composition 2a relative to the sum of the first material and the second material is preferably 50% by mass or more and 90% by mass or less. That is, the content ratio of the first (meth)acrylate compound relative to the sum of the first (meth)acrylate compound and the second (meth)acrylate compound in the cured product 2 is preferably in the range of 50% by mass or more and 90% by mass or less. This is to ensure high transfer accuracy of the cured product 2 and an excellent water absorption expansion coefficient.

[0041] The length of the ether moiety represented by the average value of m+n in the above general formula (3) is preferably short. The longer the length of the ether moiety, the greater the flexibility of the resin composition 2a and the softer the cured product 2, but there is a risk of the coefficient of water absorption swelling becoming higher. From the viewpoint of reducing the coefficient of water absorption swelling of the cured product 2, the average value of m+n is preferably in the range of 2 or more and 10 or less. The average value of m+n is more preferably in the range of 2 or more and 5 or less.

[0042] The resin composition 2a may contain a polymerization initiator. The polymerization initiator may be a photopolymerization initiator or a thermal polymerization initiator, and can be determined depending on the selected manufacturing process. However, when replica molding is performed to produce an aspherical shape, a photopolymerization initiator is preferred from the viewpoint of fast curing speed. Examples of commercially available photopolymerization initiators include 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-1-butanone, 1-hydroxycyclohexyl phenyl ketone, bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide, 4-phenylbenzophenone, 4-phenoxybenzophenone, 4,4'-diphenylbenzophenone, and 4,4'-diphenoxybenzophenone. The content of the photopolymerization initiator in the resin composition 2a is preferably in the range of 0.01% by mass to 10% by mass. If the content of the photopolymerization initiator is less than 0.01% by mass, sufficient reactivity may not be obtained, and if it exceeds 10% by mass, there is a risk of a decrease in the transmittance of the cured product 2. Note that unreacted polymerization initiator remains in the cured product 2.

[0043] Furthermore, the resin composition 2a may contain additives such as a polymerization inhibitor, an antioxidant, a light stabilizer (HALS), an ultraviolet absorber, a silane coupling agent, a release agent, a pigment, and a dye, as required.

[0044] The cured product 2 preferably has high transparency. Specifically, the transmittance at a wavelength of 400 nm, converted into a thickness of 500 μm, is preferably 70% or more. The Abbe number of the cured product 2 is also preferably 40 or more. Within these ranges, the optical element 10 can be adapted to various optical designs when used as a lens in an optical system.

[0045] In FIG. 1, the thickness of the cured product 2 is not uniform within the first surface 1A. That is, the surface of the cured product 2 not in contact with the transparent substrate 1 has an aspherical shape. In this embodiment, the thickness distribution is such that the thickness is thin near the center O of the element, reaching a minimum thickness d1, and reaches a maximum thickness d2 at the periphery of the element, but this shape is not necessarily required. For example, the thickness distribution may be such that the thickness is maximum d2 near the center O of the element and reaches a minimum thickness d1 at the periphery of the element. The ratio of the maximum thickness d2 to the minimum thickness d1 of the cured product 2 is preferably greater than 1 and less than or equal to 30. If the ratio is greater than 30, the difference in thickness of the cured product 2 is so large that high surface precision may not be maintained during cure shrinkage. Note that the minimum thickness d1 is preferably 300 μm or less, and the maximum thickness d2 is preferably 10 μm or more and 1000 μm or less.

[0046] Furthermore, the coefficient of water absorption of the cured product 2 provided on the transparent substrate 1 is preferably less than 0.30%. This is because fluctuations in optical properties due to water absorption and expansion can be minimized. If the coefficient of water absorption and expansion is 0.30% or more, the change in the surface shape of the cured product 2 before and after water absorption will be significant, which may affect image quality when used in an optical system. Therefore, the coefficient of water absorption and expansion is preferably less than 0.20%, and more preferably 0.15% or less. The coefficient of water absorption and expansion is measured by placing the optical element 10 in a thermo-hygrostat chamber at a temperature of 40°C and a humidity of 90% for 16 hours, and then removing it from the chamber to room temperature (23°C±2°C) for 20 minutes, and then evaluating the surface shape of the cured product 2 with a shape measuring instrument.

[0047] In this embodiment, the optical element 10 has the transparent substrate 1, but the optical element 10 may not have the transparent substrate 1 depending on the optical properties of the optical element 10.

[0048] [Method of manufacturing optical elements] Although the method for manufacturing the optical element according to the first embodiment is not particularly limited, an example of a suitable manufacturing process will be described below. Figure 2 is a schematic diagram showing the method for manufacturing the optical element according to the first embodiment.

[0049] First, a transparent substrate 1 and a resin composition 2a are prepared (preparation step). To improve adhesion between the transparent substrate 1 and the cured product 2, it is preferable to pretreat the first surface 1A of the transparent substrate. If the transparent substrate 1 is glass, for example, silane coupling treatment, corona discharge treatment, UV ozone treatment, or plasma treatment can be selected. From the viewpoint of further enhancing adhesion by directly chemically bonding the first surface 1A and the cured product 2, it is preferable to perform the coupling treatment using a silane coupling agent. Specific examples of coupling agents include hexamethyldisilazane, methyltrimethoxysilane, trimethylchlorosilane, and triethylchlorosilane.

[0050] Next, as shown in FIG. 2(a), a resin composition 2a is dropped onto the mold 4. The resin composition 2a is a UV-curable composition containing a photopolymerization initiator. The transparent substrate 1 is placed on an ejector 5 and positioned opposite the mold 4. The mold 4 is, for example, a metal mold having a desired aspherical inverted shape on its surface, which can be produced by cutting a metal base material such as stainless steel or steel plated with NiP or oxygen-free copper using a precision machining machine. The surface of the mold 4 may also be coated with a release agent to control the release properties of the resin. The type of release agent is not particularly limited, but examples include fluorine coating agents.

[0051] 2(b), the ejector 5 is lowered so that the mold 4 approaches the transparent substrate 1, thereby providing the resin composition 2a on the transparent substrate 1 (setting step). The ejector 5 is further lowered so that the uncured resin composition 2a fills the space between the mold 4 and the transparent substrate 1, and is molded into a desired shape (molding step).

[0052] Then, by irradiating the transparent substrate 1 with ultraviolet light from the second surface 1B side using an ultraviolet light source 6, a cured product 2 that is a polymerized and cured product of the resin composition 2a is obtained (curing step, light irradiation step).

[0053] Thereafter, the polymerized and cured cured product 2 is released from the mold 4, thereby obtaining an optical element 10 having the aspherical cured product 2 on the transparent substrate 1. After the cured product 2 is formed, it may be subjected to additional ultraviolet irradiation or heat treatment in the air or in an oxygen-free atmosphere.

[0054] The optical element of the first embodiment can be manufactured by the above manufacturing method. In the setting step, the resin composition 2a may be dripped onto both the mold 4 and the transparent substrate 1, or onto only the transparent substrate 1. In addition, if the resin composition 2a contains a thermal polymerization initiator as a curing initiator, the light irradiation step may be changed to a heat treatment step. Furthermore, after the curing step, the transparent substrate 1 may be peeled off from the optical element 10, and only the cured product 2 may be used as the optical element 10.

[0055] (Second embodiment) [Optical equipment] Specific application examples of the optical element of the first embodiment include lenses constituting optical equipment (photography optical systems) for cameras and video cameras, and lenses constituting optical equipment (projection optical systems) for liquid crystal projectors. It can also be used as a pickup lens for DVD recorders and the like. These optical systems are composed of at least one lens arranged in a housing, and the optical element of the first embodiment can be used for at least one of these lenses.

[0056] (Third embodiment) [Imaging device] 3 is a schematic diagram showing the configuration of a single-lens reflex digital camera 100, which is an example of a preferred embodiment of an imaging device using the optical element of the first embodiment. In FIG. 3, a camera body 602 and a lens barrel 601, which is an optical device, are coupled together, and the lens barrel 601 is a so-called interchangeable lens that can be attached to and detached from the camera body 602.

[0057] Light from a subject is captured via an optical system consisting of multiple lenses 603, 605, etc., arranged on the optical axis of the photographing optical system inside a housing 620 of a lens barrel 601. The optical element of the first embodiment can be used for the lenses 603, 605, for example. Here, the lens 605 is supported by an inner barrel 604, and is movably supported relative to the outer barrel of the lens barrel 601 for focusing and zooming.

[0058] During the observation period before shooting, light from the subject is reflected by a primary mirror 607 inside the camera body housing 621, passes through a prism 611, and then is projected to the photographer through a viewfinder lens 612 as a captured image. The primary mirror 607 is, for example, a half mirror, and light passing through the primary mirror is reflected by a secondary mirror 608 toward an AF (autofocus) unit 613. This reflected light is used, for example, for distance measurement. The primary mirror 607 is attached and supported by a primary mirror holder 640, for example, by adhesive. During shooting, a drive mechanism (not shown) moves the primary mirror 607 and secondary mirror 608 out of the optical path, opens a shutter 609, and allows an image sensor 610 to receive light that has entered through the lens barrel 601 and passed through the shooting optical system, forming a captured optical image. The aperture 606 is configured so that the brightness and depth of focus during shooting can be changed by changing the aperture area.

[0059] Although the imaging device has been described here using a single-lens reflex digital camera, it can also be used in smartphones, compact digital cameras, drones, etc. [Example]

[0060] The following description will be given with reference to examples and comparative examples. First, the evaluation methods used in the examples and comparative examples will be described.

[0061] [Evaluation method] (Refractive index nd of d line and Abbe number νd) The refractive index nd and Abbe number νd of the cured products of the optical elements of the examples and comparative examples were evaluated by preparing samples for evaluating optical properties. It is also possible to peel off the transparent substrate from the optical element and remove the cured product for evaluation without using a sample for evaluating optical properties. First, a method for preparing a sample for evaluating optical properties will be described.

[0062] A 500 μm thick spacer and an uncured resin composition, which was a precursor to the cured product to be measured, were placed on a 1 mm thick glass (S-TIH, manufactured by Ohara Corporation). A 1 mm thick quartz glass was placed on top of the glass via the spacer, and the uncured resin composition was spread. Next, the spacer was removed, and a high-pressure mercury lamp (UL750, manufactured by HOYA CANDEO OPTRONICS) was used to illuminate the uncured resin composition from above the quartz glass at 20 mW / cm. 2 The resin composition was cured, the quartz glass was removed, and the resin composition was annealed at 80°C for 16 hours to prepare a sample for evaluating optical properties. The cured product had a thickness of 500 μm and a size of 5 mm × 20 mm within the glass surface.

[0063] The refractive index nf at the f-line (486.1 nm), the refractive index nd at the d-line (587.6 nm), and the refractive index nc at the c-line (656.3 nm) were measured for the obtained sample from the glass side using a refractometer (KPR-30, manufactured by Shimadzu Corporation).

[0064] The Abbe number νd was calculated from the measured refractive indexes using the following formula: Abbe number νd=(nd-1) / (nf-nc)

[0065] (Minimum thickness d1, maximum thickness d2) The minimum thickness d1 and maximum thickness d2 of the cured product of the optical elements of the Examples and Comparative Examples were evaluated using optical elements in which the cured product was provided on a transparent substrate.

[0066] First, the fabricated optical element was placed in a thermostatic chamber at 80°C for 16 hours. The optical element was then removed to room temperature (23°C ± 2°C). After 20 minutes, the surface shape of the cured product was evaluated using a profile measuring instrument (Form Talysurf Laser, manufactured by Taylor Hobson). Measurements were performed by optically scanning a straight line from the edge of the optical element through the center to the opposite edge at a scanning speed of 0.5 mm / sec. The vertical distance from the interface between the transparent substrate 1 and the cured product 2 to the measured surface shape of the cured product 2 was calculated to obtain the thickness D of the cured product 2. The thickness D is shown in Figure 4. Furthermore, the average radial thickness was defined as D0, the minimum thickness as d1, and the maximum thickness as d2.

[0067] (Water absorption expansion rate) The coefficient of water absorption expansion of the cured products of the optical elements of the Examples and Comparative Examples was evaluated using optical elements each having a cured product provided on a transparent substrate.

[0068] First, the fabricated optical element was placed in a thermo-hygrostat chamber at 40°C and 90% humidity for 16 hours. The optical element was then removed to room temperature (23°C ± 2°C), and after 20 minutes, the surface shape of the cured product was evaluated using a profile measuring instrument (Form Talysurf Laser, manufactured by Taylorhobson). Measurements were performed by optically scanning a straight line from the edge of the optical element, passing through the center, to the opposite edge, at a scanning speed of 0.5 mm / sec. The water absorption expansion coefficient [%] of the optical element was calculated using the following formula from the average thickness (D0) before water absorption and the average thickness (D1) after water absorption. Water absorption expansion rate [%] = ((D1-D0) / D0) x 100

[0069] (evaluation) A: The cured product does not peel off and has a water absorption expansion rate of less than 0.20%. B: The cured product does not peel off and has a water absorption expansion rate of less than 0.30%. C: The cured product has peeled off or the water absorption expansion rate is 0.30% or more.

[0070] [Fabrication of optical elements] Example 1 First, a resin composition serving as a precursor for the cured product was prepared. As a first material having an alicyclic skeleton and a monofunctional or difunctional first (meth)acrylate polymerizable functional group, 70 parts by mass of (A-1) dicyclopentamethacrylate (monofunctional, FA-513M, manufactured by Showa Denko Materials Co., Ltd.) was prepared. Furthermore, as a second material having a bisphenol skeleton and a difunctional (meth)acrylate polymerizable functional group, 30 parts by mass of (B-1) bisphenol A EO adduct dimethacrylate (difunctional, m + n = 7, BPE-300, manufactured by Shin-Nakamura Chemical Co., Ltd.) was prepared. Furthermore, as a polymerization initiator, 2 parts by mass of (C-1) 1-hydroxycyclohexyl phenyl ketone (photopolymerization initiator, Omnirad 184, manufactured by IGM Resins) was prepared. These materials were placed in a bottle and mixed uniformly to obtain Resin Composition 2a of Example 1.

[0071] Next, the optical element shown in FIG. 1 was manufactured using the manufacturing method shown in FIG. 2. An optical glass (S-TIM8, manufactured by Ohara Inc.) with a diameter of 32 mm was prepared as the transparent substrate 1. One surface (first surface 1A) was a concave spherical shape with a radius of 40 mm, and the other surface (second surface 1B) was a convex spherical shape with a radius of 75 mm. The mold 4 was made by cutting a NiP layer plated on a metal base material with a precision machining machine to form a shape that was the inverse of the aspherical shape of the cured product 2 to be molded.

[0072] Subsequently, the resin composition 2a was filled between the transparent substrate 1 and the mold 4. Thereafter, in order to cure the resin composition 2a, a light having an intensity of 10 mW / cm at a wavelength of 365 nm was applied. 2 The entire surface was irradiated with ultraviolet light of 80° C. for 200 seconds. After the mold 4 was released, the transparent substrate 1 was heated at 80° C. for 24 hours to form a cured product 2 on the first surface 1A of the transparent substrate 1, thereby obtaining the optical element 10 of Example 1.

[0073] The cured product 2 of Example 1 had a refractive index nd of 1.53 for the d-line and an Abbe number vd of 47. The cured product of the optical element of Example 1 had a shape in which the thickness was smallest at the center and largest at the periphery. The minimum thickness d1 was 50 μm, the maximum thickness d2 was 400 μm, and d2 / d1 was 8.0. The coefficient of swelling by water absorption was 0.15%, and no peeling was observed, so the evaluation was A.

[0074] Example 2 Example 2 differs from Example 1 in the composition of the resin composition. Specifically, Example 2 differs from Example 1 in that 30 parts by mass of (B-2) EO adduct dimethacrylate of bisphenol A (bifunctional, m+n=10, BPE-500, manufactured by Shin-Nakamura Chemical Co., Ltd.) was prepared as the second material. Also, the shape of the mold 4 differs from Example 1. Except for these points, the optical element of Example 2 was produced in the same manner as Example 1.

[0075] The cured product of Example 2 had a refractive index nd of 1.53 for d-line and an Abbe number vd of 48. The minimum thickness d1 was 30 μm, the maximum thickness d2 was 380 μm, and d2 / d1 was 12.7. The coefficient of swelling by water absorption was 0.19%, and no peeling was observed, so the product was rated A.

[0076] Example 3 Example 3 differs from Example 1 in the composition of the resin composition. Specifically, Example 3 differs from Example 1 in that 30 parts by mass of (B-3) EO adduct dimethacrylate of bisphenol A (bifunctional, m+n=2.3, BPE-80N, manufactured by Shin-Nakamura Chemical Co., Ltd.) was prepared as the second material. Except for this, the optical element of Example 3 was produced in the same manner as Example 1.

[0077] The cured product of Example 3 had a refractive index nd of 1.53 for d-line and an Abbe number vd of 47. The minimum thickness d1 was 50 μm, the maximum thickness d2 was 400 μm, and d2 / d1 was 8.0. The coefficient of swelling by water absorption was 0.07%, and no peeling was observed, so the product was rated A.

[0078] Example 4 Example 4 differs from Example 1 in the composition of the resin composition. Specifically, Example 4 differs from Example 1 in that 30 parts by mass of (B-4) EO adduct diacrylate of bisphenol A (bifunctional, m+n=3, ABE-300, manufactured by Shin-Nakamura Chemical Co., Ltd.) was prepared as the second material. Except for this, the optical element of Example 4 was produced in the same manner as Example 1.

[0079] The cured product of Example 4 had a refractive index nd of 1.53 for d-line and an Abbe number vd of 47. The minimum thickness d1 was 50 μm, the maximum thickness d2 was 400 μm, and d2 / d1 was 8.0. The coefficient of swelling by water absorption was 0.07%, and no peeling was observed, so the product was rated A.

[0080] Example 5 Example 5 differs from Example 1 in the composition of the resin composition. Specifically, Example 5 differs from Example 1 in that 30 parts by mass of (A-1) dicyclopentamethacrylate (monofunctional, FA-513M, manufactured by Showa Denko Materials Co., Ltd.) and 40 parts by mass of (A-2) dimethyloltricyclodecane diacrylate (bifunctional, A-DCP, manufactured by Shin-Nakamura Chemical Co., Ltd.) were prepared as the first material. Example 5 also differs from Example 1 in that 30 parts by mass of (B-3) EO adduct dimethacrylate of bisphenol A (bifunctional, m+n=2.3, BPE-80N, manufactured by Shin-Nakamura Chemical Co., Ltd.) were prepared as the second material. Except for these differences, the optical element of Example 5 was fabricated in the same manner as Example 1.

[0081] The cured product of Example 5 had a refractive index nd of 1.53 for d-line and an Abbe number vd of 47. The minimum thickness d1 was 50 μm, the maximum thickness d2 was 400 μm, and d2 / d1 was 8.0. The coefficient of swelling by water absorption was 0.14%, and no peeling was observed, so the product was rated A.

[0082] Example 6 Example 6 differs from Example 1 in the composition of the resin composition. Specifically, Example 6 differs from Example 1 in that 70 parts by mass of (A-3) dimethyloltricyclodecane dimethacrylate (bifunctional, DCP-M, manufactured by Kyoeisha Chemical Co., Ltd.) was prepared as the first material. Example 6 also differs from Example 1 in that 30 parts by mass of (B-3) bisphenol A EO adduct dimethacrylate (bifunctional, m+n=2.3, BPE-80N, manufactured by Shin-Nakamura Chemical Co., Ltd.) was prepared as the second material. Except for these differences, the optical element of Example 6 was fabricated in the same manner as Example 1.

[0083] The cured product of Example 6 had a refractive index nd of 1.54 for d-line and an Abbe number vd of 46. The minimum thickness d1 was 50 μm, the maximum thickness d2 was 400 μm, and d2 / d1 was 8.0. The coefficient of swelling by water absorption was 0.15%, and no peeling was observed, so the product was rated A.

[0084] Example 7 Example 7 differs from Example 1 in the composition of the resin composition. Specifically, Example 7 differs from Example 1 in that 35 parts by mass of (A-1) dicyclopentamethacrylate (monofunctional, FA-513M, manufactured by Showa Denko Materials Co., Ltd.) and 55 parts by mass of (A-2) dimethyloltricyclodecane diacrylate (bifunctional, A-DCP, manufactured by Shin-Nakamura Chemical Co., Ltd.) were prepared as the first material. Example 7 also differs from Example 1 in that 10 parts by mass of (B-3) EO adduct dimethacrylate of bisphenol A (bifunctional, m+n=2.3, BPE-80N, manufactured by Shin-Nakamura Chemical Co., Ltd.) were prepared as the second material. Except for these differences, the optical element of Example 7 was fabricated in the same manner as Example 1.

[0085] The cured product of Example 7 had a refractive index nd of 1.53 for d-line and an Abbe number vd of 49. The minimum thickness d1 was 50 μm, the maximum thickness d2 was 400 μm, and d2 / d1 was 8.0. The coefficient of swelling due to water absorption was 0.17%, and no peeling was observed, so the product was rated A.

[0086] Example 8 Example 8 differs from Example 1 in the composition of the resin composition. Specifically, Example 8 differs from Example 1 in that 40 parts by mass of (A-2) dimethyloltricyclodecane diacrylate (bifunctional, A-DCP, manufactured by Shin-Nakamura Chemical Co., Ltd.) and 30 parts by mass of (A-4) isobornyl methacrylate (bifunctional, IB, manufactured by Shin-Nakamura Chemical Co., Ltd.) were prepared as the first material. Example 8 also differs from Example 1 in that 30 parts by mass of (B-3) EO adduct dimethacrylate of bisphenol A (bifunctional, m+n=2.3, BPE-80N, manufactured by Shin-Nakamura Chemical Co., Ltd.) were prepared as the second material. Except for these differences, the optical element of Example 8 was fabricated in the same manner as Example 1.

[0087] The cured product of Example 8 had a refractive index nd of 1.54 for d-line and an Abbe number vd of 47. The minimum thickness d1 was 50 μm, the maximum thickness d2 was 400 μm, and d2 / d1 was 8.0. The coefficient of swelling due to water absorption was 0.13%, and no peeling was observed, so the product was rated A.

[0088] Example 9 Example 9 differs from Example 1 in the composition of the resin composition. Specifically, Example 9 differs from Example 1 in that 30 parts by mass of (B-5) EO adduct dimethacrylate of bisphenol A (bifunctional, m+n=17, BPE-900, manufactured by Shin-Nakamura Chemical Co., Ltd.) was prepared as the second material. In all other respects, the optical element of Example 9 was produced in the same manner as Example 1.

[0089] The cured product of Example 9 had a refractive index nd of 1.52 for d-line and an Abbe number vd of 48. The minimum thickness d1 was 50 μm, the maximum thickness d2 was 400 μm, and d2 / d1 was 8.0. The coefficient of swelling due to water absorption was 0.26%, and no peeling was observed, so the product was evaluated as B.

[0090] (Comparative Example 1) Comparative Example 1 differs from Example 1 in the composition of the resin composition. Specifically, it differs from Example 1 in that 100 parts by mass of (B-6) EO adduct acrylate of bisphenol A (bifunctional, m+n=3, ABE-30, manufactured by Shin-Nakamura Chemical Co., Ltd.) was prepared as the second material. In Comparative Example 1, the first material was not prepared. The optical element of Comparative Example 1 was produced in the same manner as Example 1 except for the above.

[0091] The cured product of Comparative Example 1 had a refractive index nd of 1.56 for d-line and an Abbe number vd of 35. The minimum thickness d1 was 50 μm, the maximum thickness d2 was 400 μm, and d2 / d1 was 8.0. The coefficient of swelling due to water absorption was 0.30%, so the product was evaluated as C.

[0092] The compounding ratios of the resin compositions of Examples 1 to 9 and Comparative Example 1 are shown in Table 1.

[0093] [Table 1]

[0094] The alphanumeric characters shown in the type column in Table 1 refer to the following:

[0095] (A) First material A-1: Dicyclopentamethacrylate (monofunctional, FA-513M, Showa Denko Materials Co., Ltd.) A-2: Dimethyloltricyclodecane diacrylate (bifunctional, A-DCP, manufactured by Shin-Nakamura Chemical Co., Ltd.) A-3: Dimethyloltricyclodecane dimethacrylate (bifunctional, DCP-M, manufactured by Kyoeisha Chemical Co., Ltd.) A-4: Isobornyl methacrylate (bifunctional, IB, manufactured by Shin-Nakamura Chemical Co., Ltd.)

[0096] (B) Second material B-1: EO adduct dimethacrylate of bisphenol A (bifunctional, m+n=7, BPE-300, manufactured by Shin-Nakamura Chemical Co., Ltd.) B-2: EO adduct dimethacrylate of bisphenol A (bifunctional, m+n=10, BPE-500, manufactured by Shin-Nakamura Chemical Co., Ltd.) B-3: EO adduct dimethacrylate of bisphenol A (bifunctional, m+n=2.3, BPE-80N, manufactured by Shin-Nakamura Chemical Co., Ltd.) B-4: EO adduct diacrylate of bisphenol A (bifunctional, m+n=3, ABE-300, manufactured by Shin-Nakamura Chemical Co., Ltd.) B-5: EO adduct dimethacrylate of bisphenol A (bifunctional, m+n=17, BPE-900, manufactured by Shin-Nakamura Chemical Co., Ltd.) B-6: EO adduct acrylate of bisphenol A (bifunctional, m+n=3, ABE-30, manufactured by Shin-Nakamura Chemical Co., Ltd.)

[0097] (C) Polymerization initiator C-1: 1-hydroxycyclohexyl phenyl ketone (photopolymerization initiator, Omnirad 184, manufactured by IGM Resins) Table 2 shows the evaluation results of the optical elements of Examples 1 to 9 and Comparative Example 1.

[0098] [Table 2]

[0099] Table 2 shows that Examples 1 to 9, which contain the first material and the second material as resin composition 2a, have a water absorption swelling coefficient of less than 0.30%, which is lower than that of Comparative Example 1, which uses a resin composition containing only the second material. Furthermore, Examples 1 to 8, in which the average value of m+n is 10 or less, have a water absorption swelling coefficient of less than 0.20%, which is lower than that of Example 9, in which the average value of m+n is 17.

[0100] From the above, it was found that an optical element comprising a cured product containing a monofunctional or bifunctional first (meth)acrylate compound having an alicyclic skeleton represented by general formula (1) or general formula (2) and a bifunctional second (meth)acrylate compound having a bisphenol skeleton represented by general formula (3) has a large Abbe number of 40 or more, high transfer accuracy, and an excellent coefficient of water swelling. As a result, it was found that an optical element can be provided whose optical performance is less likely to fluctuate even in a high-humidity environment. [Explanation of symbols]

[0101] 1 Transparent base material 1A 1st page 1B 2nd side 2 Cured product 2a Resin composition Type 4 5 Ejector 10 Optical Elements 600 SLR digital camera (imaging device) 601 Lens barrels (interchangeable lenses, optical equipment) 602 Camera body 603 Lens (optical element) 604 Inner cylinder 605 Lens (optical element) 606 Aperture 607 Primary Mirror 608 submirror 609 Shutter 610 Image sensor 611 Prism 621 Case

Claims

1. The present invention comprises a cured product obtained by curing a resin composition containing a monofunctional or bifunctional first (meth)acrylate compound having an alicyclic skeleton represented by the following general formula (1) or general formula (2) and a bifunctional second (meth)acrylate compound having a bisphenol skeleton represented by the following general formula (3), and a transparent substrate on which the cured product is provided: the content ratio of the first (meth)acrylate compound and the second (meth)acrylate compound in the cured product is in the range of 90% by mass or more and 99.5% by mass or less, a content ratio of the first (meth)acrylate compound to the sum of the first (meth)acrylate compound and the second (meth)acrylate compound in the cured product is in the range of 50% by mass or more and 90% by mass or less, the ratio of the maximum thickness d2 of the cured product to the minimum thickness d1 is greater than 1 and less than 30; An optical element characterized in that the minimum thickness d1 is 300 μm or less, and the maximum thickness d2 is in the range of 10 μm or more and 1000 μm or less. 【Chemical 1】 【Chemistry 2】 【Chemistry 3】 (In the above general formula (3), R １ and R ２ represents a hydrogen atom or a methyl group, and m+n represents a numerical value.

2. 2. The optical element according to claim 1, wherein the average value of m+n in the general formula (3) is in the range of 2 or more and 10 or less.

3. 3. The optical element according to claim 1, wherein the average value of m+n in the general formula (3) is in the range of 2 or more and 5 or less.

4. The optical element according to claim 1 , wherein the cured product further contains a polymerization initiator.

5. 5. The optical element according to claim 1, wherein the cured product has a transmittance of 70% or more at a wavelength of 400 nm when converted into a thickness of 500 [mu]m.

6. The optical element according to claim 1 , wherein the cured product has an Abbe number of 40 or more.

7. the transparent substrate has a first surface that is a concave spherical surface, The optical element according to claim 1 , wherein the cured product is provided on the first surface.

8. 8. The optical element according to claim 1, wherein the cured product has a coefficient of water swelling of less than 0.30%.

9. a preparation step of preparing a transparent substrate, a resin composition including a first material having a polymerizable functional group of a monofunctional or bifunctional (meth)acrylate having an alicyclic skeleton represented by the following general formula (1) or (2), a second material having a polymerizable functional group of a bifunctional (meth)acrylate having a bisphenol skeleton represented by the following general formula (3), and a polymerization initiator; an installation step of providing the resin composition on the transparent substrate; a curing step of curing the resin composition to form a cured product; a step of obtaining the optical element according to any one of claims 1 to 8 through the curing step; 1. A method for manufacturing an optical element, comprising: 【Chemistry 4】 【Chemistry 5】 【Chemistry 6】 (In the above general formula (3), R １ and R ２ represents a hydrogen atom or a methyl group, and m+n represents a numerical value.

10. The method for manufacturing an optical element according to claim 9 , wherein the placing step includes a molding step of molding the resin composition using a mold.

11. the polymerization initiator is a photopolymerization initiator, The method for manufacturing an optical element according to claim 9 or 10, wherein the curing step includes a light irradiation step of curing the resin composition by light irradiation.

12. 1. An optical instrument comprising: a housing; and an optical system having at least one lens disposed within the housing, An optical device, wherein at least one of the lenses is the optical element according to any one of claims 1 to 8.

13. An imaging device having a housing, an optical system having at least one lens disposed in the housing, and an imaging element that receives light that has passed through the optical system, An imaging device, wherein at least one of the lenses is the optical element according to claim 1 .

Images