JP2010211115A - Composite optical element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a composite optical element composed of only resin having an effect for reducing chromatic aberration and other aberration in an optical system. <P>SOLUTION: The composite optical element is obtained by mutually sticking and laminating two layers, i.e. a synthetic resin layer containing sulfur in a repeating unit and a synthetic resin layer having any ring structure out of a benzene ring, a naphthalene ring and an anthracene ring and not containing sulfur in a repeating unit. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a composite optical element made of only a resin effective in reducing chromatic aberration and other aberrations in an optical system.

  In recent years, downsizing, high performance, and weight reduction of optical systems used in cameras, video cameras, camera-equipped mobile phones, videophones, camera-equipped doorphones, and the like have become major issues. Therefore, in order to eliminate aberrations in these optical systems, composite elements such as a cemented lens and a laminated diffractive element are often used. These composite elements are particularly effective in reducing chromatic aberration among aberrations, and the magnitude of the effect is determined by the combination of the optical characteristics of the lens material used.

Conventionally, glass has been used as at least one material of the composite element because optical properties that can be realized only with synthetic resin are limited. However, these optical materials made of synthetic resin have good workability and are lightweight. It is required to be used for the purpose.
However, the optical properties of the synthetic resin optical materials so far have been insufficient for the optical characteristics. For example, in order to express a specific optical characteristic capable of correcting chromatic aberration, a low refractive index and low dispersion material such as a fluororesin is used, and it is difficult to realize a composite optical element using a high refractive index resin (for example, Patent Document 1).
In addition to the aberration reduction effect other than chromatic aberration in the composite optical element, in order to reduce the size of the optical system, it is effective to use a surface other than the cemented surface in addition to the cemented surface as a spherical surface, an aspherical surface, etc. In order to increase the curvature radius of these spherical and aspherical surfaces and reduce the element thickness, it is desirable that the resin has a high refractive index.

International publication pamphlet WO2003 / 046615

In conventional composite optical elements using only synthetic resins, low refractive index and low dispersion materials such as fluororesin are used to express specific optical characteristics that enable chromatic aberration correction. Realization of a composite optical element has become difficult.
In addition to providing an aberration reduction effect other than chromatic aberration with a composite optical element and realizing a compact optical system, in addition to the joint surface, surfaces other than the joint surface should be used as spherical surfaces, aspheric surfaces, etc. In order to increase the radius of curvature of these spherical and aspherical surfaces and reduce the element thickness, a resin having a high refractive index is indispensable.
It is an object of the present invention to provide a composite optical element made of a synthetic resin that enables downsizing and high performance of an optical system.

In the present invention, two layers of a synthetic resin layer containing sulfur in a repeating unit and a synthetic resin layer not containing sulfur having a cyclic structure of any one of a benzene ring, a naphthalene ring and an anthracene ring in the repeating unit are adhered to each other. It is a laminated composite optical element.
In the composite optical element, the synthetic resin layer containing sulfur is obtained by polymerizing a polymerizable composition containing an episulfide compound.
In the composite optical element, the episulfide compound contains an alkyl episulfide compound.

Further, the refractive index nd of the d-line of the synthetic resin layer containing sulfur in the repeating unit is nd> 1.60, the Abbe number is 40>νd> 30, and the anomalous dispersion θgF is −0.015 ≦ ΔθgF ≦ 0. The composite optical element is 075.
The refractive index nd of the d-line of the synthetic resin layer containing sulfur in the repeating unit is nd> 1.66, the Abbe number is 38>νd> 28, and the anomalous dispersion θgF is −0.015 ≦ ΔθgF ≦ 0.075. The composite optical element described above.
In the composite optical element, the transmittance at 1 mm thickness of the synthetic resin layer containing sulfur in the repeating unit is 70% or more at 450 nm.
In the composite optical element, the synthetic resin layer having any one of a benzene ring, a naphthalene ring, and an anthracene ring in the repeating unit and containing no sulfur in the repeating unit.
In the composite optical element, the surface on which the synthetic resin is laminated is an aspherical surface.
In the composite optical element, the surface on which the synthetic resin is laminated is a diffraction surface.

FIG. 1 is a view showing an example of a molding apparatus used for molding an optical element which is a substrate of the composite optical element of the present invention. FIG. 2 is a diagram illustrating an example of a composite optical element. FIG. 3 is a diagram illustrating an example of an apparatus for manufacturing a composite optical element. FIG. 4 is a diagram for explaining the anomalous dispersion ΔθgF.

According to the present invention, in a composite optical element in which two synthetic resin layers are adhered and laminated, any one of the synthetic resin layers is a synthetic resin layer containing sulfur as a repeating unit. It has been found that a composite optical element effective in reducing aberration can be obtained.
Here, the composite optical element in which two synthetic resin layers are laminated in close contact refers to an element that is composed of two intimate synthetic resin layers and that controls the light traveling direction and the amount of light in the optical system. Examples of the bonded synthetic resin layer bonding surface include a diffractive surface, a flat surface, a spherical surface, an aspherical surface, a free-form surface, and a cylindrical surface, and may have a nano-order fine structure at the same time. Specific examples include a cemented lens and a diffraction element. In addition, the two synthetic resin layers in close contact may be obtained by laminating the above synthetic resins, and another optical layer may be further laminated.

In order to exhibit a chromatic aberration reduction effect in a compound optical element such as a cemented lens or a diffractive element, the combination of optical characteristics of the lens material is relatively lower than that of the lens material having a high refractive index and low dispersion. It is necessary to use a lens material having a refractive index and high dispersion.
The present invention provides a sulfur-containing polymerizable composition as a synthetic resin material having a high refractive index and low dispersion when realizing these composite optical elements only with a synthetic resin in order to reduce the weight of the optical system. It was found that the synthetic resin layer obtained by the polymerization of was effective.

  In addition, in order to have an effect of reducing aberrations other than chromatic aberration in the composite optical element of the present invention, light such as a spherical surface, an aspherical surface, a free-form surface, or a cylindrical surface is refracted on a cemented surface and a surface other than the cemented surface. It is effective to make the surface (surface with power). By designing the shape of these surfaces, aberrations other than chromatic aberration can be reduced. In order to further reduce the aberration, it is more preferable that all the surfaces other than the joint surface and the joint surface are refracting surfaces. In a composite optical element having such a refractive surface, since it is possible to reduce the size of the element by using a high refractive index resin material, it is important to use a high refractive index material. The merit of using a resin containing sulfur having a high refractive index in its repeating unit is particularly remarkable.

In the composite optical element of the present invention, it is more preferable that the joint surface is a diffractive surface or an aspherical surface. In a composite optical element that is effective in reducing chromatic aberration, the diffractive element is very useful as a chromatic aberration reducing element because the effect of correcting the chromatic aberration is reverse to that of a normal cemented lens. Further, it is useful that the cemented surface is aspherical because it has a great effect on reducing aberrations other than chromatic aberration.
Synthetic resins containing sulfur in the repeating unit include resins containing sulfur in the main chain and side chain of the repeating unit, such as thiourethane resins and synthetic resins having an episulfide structure, and other polymerizable functional groups. Etc. Here, it is more preferable that the polymerizable functional group includes an acryloyl group, a methacryloyl group, and a vinyl group.

Moreover, it is desirable that the synthetic resin containing sulfur in the repeating unit does not contain an alicyclic structure. The alicyclic structure tends to increase the dispersion as compared with the linear or branched structure, and it becomes difficult to realize a high refractive index and a low dispersion.
The repeating unit preferably contains a heterocyclic ring or a benzene ring structure in addition to sulfur. When a heterocyclic ring or a benzene ring structure is included, the dispersion increases, but it is effective for increasing the refractive index.
Among these resins containing sulfur as a repeating unit, a resin obtained by curing an episulfide compound is optimal for achieving a high refractive index and low dispersion.
In particular, among the episulfide compounds, the alkyl episulfide compound does not contain an alicyclic structure or a benzene ring structure that increases dispersibility in its structural unit, so low dispersibility can be maintained, and thus low dispersion is required while having a high refractive index. Effective in applications.
Here, as an alkyl episulfide compound, the alkyl group may be linear or branched.
In addition, the synthetic resin layer containing sulfur in the repeating unit and the synthetic resin layer having a cyclic structure of any one of a benzene ring, a naphthalene ring, and an anthracene ring in the repeating unit, and containing no sulfur are a single synthetic resin. Or a mixture of a plurality of synthetic resins. Also, those formed by polymerization of a single polymerizable composition, those obtained by polymerizing a composition containing a polymerizable composition containing sulfur and a polymerizable composition not containing sulfur, a benzene ring, a naphthalene ring, and an anthracene ring It may be produced from a composition obtained by polymerizing a composition containing any of the above ring structures and containing no polymerizable composition containing sulfur and other polymerizable compositions.

In the composite optical element of the present invention, the sulfur-containing resin has a refractive index nd of d-line of nd> 1.60, an Abbe number νd representing a dispersion magnitude of 55>νd> 41, a short wavelength region (blue It is desirable that the anomalous dispersion ΔθgF, which is a numerical value representing the magnitude of dispersion at (˜violet wavelength), is −0.015 ≦ ΔθgF ≦ 0.075.
Here, the Abbe number νd, which is a numerical value representing the magnitude of dispersion, and the value of the anomalous dispersion ΔθgF representing the magnitude of dispersion in the short wavelength region (blue to purple wavelength) are calculated by the following method. is there.
vd = (nd-1) / (nF-nc) Equation 1
θgF = (ng−nF) / (nF−nc) Equation 2
nd: Refractive index with respect to d-line nC: Refractive index with respect to C-line nF: Refractive index with respect to F-line ng: Refractive index with respect to g-line By the above equation 2, the respective partial dispersion ratio θgF is obtained, and the Abbe number (νd ), The vertical dispersion is the partial dispersion ratio θgF, and F7 (νd = 60.5, θgF = 0.547) and K2 (νd = 36.3, θgF = 0.583) of the optical glass are used as the reference dispersion glass. The coordinates (νd, θgF) of these two types of optical glass are connected by a straight line, and the difference in ordinate (ΔθgF) between this straight line and the coordinates indicating θgF and νd of the glass to be compared is short wavelength region (blue Anomalous dispersion ΔθgF representing the magnitude of dispersion at (˜violet wavelength).

If the refractive index nd is greater than 1.6, the curvature of the refractive surface can be reduced in order to obtain the same refractive power when used as an optical element, so that the thickness of the optical element can be reduced. On the other hand, if it is 1.6 or less, this effect is not seen so much. A higher Abbe number is desirable because the dispersion is small and the effect of reducing chromatic aberration is large. However, in the composite optical element, since the chromatic aberration is reduced by the combination of the optical characteristics of the two layers of resin, if it is too large, the balance becomes worse and the correction of aberration becomes too large.
In the refractive index region where the refractive index nd> 1.6, 41>νd> 31 is the optimum range for reducing chromatic aberration. In the same way, chromatic aberration can be satisfactorily reduced when ΔθgF representing the magnitude of dispersion in the short wavelength region is also −0.015 ≦ ΔθgF ≦ 0.075. In addition to the Abbe number, the value of anomalous dispersion is also important for correcting chromatic aberration over the entire visible range.
Furthermore, the optical system can be further miniaturized at a high refractive index such that nd> 1.66. In this refractive index region, the Abbe number νd is in the range of 38>νd> 28 and the anomalous dispersion ΔθgF is in the range of −0.015 ≦ ΔθgF ≦ 0.075, which is a suitable range for reducing aberration by combination. .

  The resin layer containing sulfur of the composite optical element of the present invention desirably has a transmittance of 1% in thickness of 70% or more at 450 nm. The high refractive index resin used in the composite optical element of the present invention contains sulfur, a benzene ring or the like in its repeating unit, and is easily colored by their structure. In particular, since coloring increases when a sulfur atom has a direct bond, it is desirable that the sulfur atom has a bond with carbon in order to make the transmittance at 1 mm thickness 70% or more at 450 nm. In addition, since these structures are colored by irradiation with ultraviolet rays or the like, it is preferable to perform thermosetting when using an energy curable resin.

Here, the resin processing method for obtaining an optical element mainly includes heating a thermoplastic resin until fluidity occurs and then injection molding with a mold and injecting a monomer into the mold to obtain a predetermined shape. Examples include energy ray curing.
As energy ray curing methods, there are ultraviolet curing and thermal curing, but ultraviolet curing has an advantage that it can be cured in a short time and an optical element can be manufactured with high productivity. Thermosetting is advantageous in that the synthetic resin is easily colored by ultraviolet rays, the synthetic resin has a low transmittance in the ultraviolet region, and the amount of energy applied is small compared to ultraviolet curing, so that the reaction control is easy.

  Examples of photopolymerization initiators include 4-dimethylaminobenzoic acid, 4-dimethylaminobenzoic acid ester, alkoxyacetophenone, benzyldimethyl ketal, benzophenone and benzophenone derivatives, alkyl benzoylbenzoate, bis (4-dialkylaminophenyl) 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-trimethylbenzoyldiphenyl Examples include phosphine oxide. These photopolymerization initiators may be used alone or in combination of two or more.

  Examples of thermal polymerization initiators include benzoyl peroxide, benzoin isopropyl ether, benzoin isobutyl ether, 2,2-azobisisobutyronitrile, 2,2-azobis-2,4-dimethylvaleronitrile, azobiscarboxamide , Isopropyl hydroperoxide, tertiary butyl hydroperoxide, cumyl hydroperoxide, 2,5-dimethyl-2,5-bishexane and the like.

In addition, it is effective to use a catalyst for the polymerization of the episulfide compound. Examples of catalysts include amines, phosphines, thiol lithium / sodium / potassium salts and crown ether complexes thereof, quaternary ammonium salts, quaternary phosphonium salts, tertiary sulfonium salts, secondary iodonium salts. Mineral acids, Lewis acids, organic acids, silicic acids, tetrafluoroboric acid and the like.
In addition to the above resin components, the resin layer of the composite optical element of the present invention may be further added with an ultraviolet absorber or an antioxidant to improve durability.

Examples of ultraviolet absorbers include salicylic acid ester-based compounds such as phenyl salicylate, p-tertiary butylphenyl salicylate, p-octylphenyl salicylate, 2,4-dihydroxybenzophenone, 2-hydroxy-4-acetoxyethoxybenzophenone, 2- Hydroxy-4-methoxybenzophenone, 2,2′-dihydroxy-4-methoxybenzophenone, 2,2′-dihydroxy-4,4′-dimethoxybenzophenone, 2-hydroxy-4-n-octoxybenzophenone, 2,2 ′ Benzophenone series such as dihydroxy-4,4′-dimethoxy-5,5′-disulfobenzophenone disodium salt, 2 (2′-hydroxy-5′-methylphenyl) benzotriazole, 2 (2′- Hydroxy-3 ', 5'-ditasi Libutylphenyl) benzotriazole, 2 (2′-hydroxy-3′-tertiarybutyl-5′-methylphenyl) -5-chlorobenzotriazole, 2 (2′-hydroxy-3 ′, 5′-ditertiarybutyl Phenyl) -5-chlorobenzotriazole, 2 (2′-hydroxy-3 ′, 5′-ditertiary amylphenyl) benzotriazole, 2 (2′-hydroxy-5′-tertiarybutylphenyl) benzotriazole, 2 ( Benzotriazoles such as 2′-hydroxy-5′-tertiary octylphenyl) benzotriazole, benzoates such as 2 ′, 4′-ditertiarybutylphenyl-3,5-ditertiarybutyl-4-hydroxybenzoate Such as ethyl-2-cyano-3,3-diphenyl acrylate Examples include anoacrylate-based compounds and aminobenzoic acid-based compounds such as butyl p-aminobenzoate. One or more of these can be selected and mixed for use.
Examples of the antioxidant include hindered phenol-based, hindered amine-based, phosphate ester-based, and sulfur-based antioxidants.

In the composite optical element of the present invention, the synthetic resin layer not containing sulfur in the repeating unit needs to have a relatively low refractive index and high dispersion as compared with the synthetic resin layer containing sulfur in the repeating unit. It is preferable that the resin layer not containing sulfur contains a benzene ring, a naphthalene ring, an anthracene ring structure, or nitrogen in the repeating unit.
In addition, if it contains a benzene ring, naphthalene ring, or anthracene ring structure, the hydrophobicity of the resin increases, and it is desirable to suppress the effect of water absorption when used as a material for optical elements. When nitrogen is included, carbon, oxygen It is desirable because it can exhibit wavelength dispersibility different from that of a resin made of hydrogen, particularly high anomalous dispersibility.
Further, the synthetic resin layer containing no sulfur in the repeating unit of the composite optical element of the present invention is a single synthetic resin having a cyclic structure of any one of a benzene ring, a naphthalene ring, and an anthracene ring, or a plurality of these. A mixture of seeds or other synthetic resin may be added.

A method for manufacturing a composite optical element will be described below with reference to the drawings.
FIG. 1 is a diagram illustrating an example of a molding apparatus that molds an optical element serving as a substrate of a composite optical element.
The optical element molding apparatus 1 includes a cylindrical metal barrel die 2, a metal upper die 3A having a desired optical surface 3A1, a metal lower die 3b having a desired optical surface 3B1, and an upper die 3A. A driving rod 5 for driving and a release cylinder 6 for releasing the cured optical element from the lower mold 3B are provided, and a heating means 4 is arranged around the metal barrel mold 2.

  The cylindrical metal barrel mold 2 is provided with an inlet 7 for injecting the polymerizable composition and an outlet 8 for discharging the excess polymerizable composition. The drive rod 5 slides up and down the upper die 3A within the metal barrel die 2 by a drive source (not shown). Further, the release cylinder 6 slides up and down in contact with the inner peripheral surface of the metal barrel mold 2. A molding chamber 9 for molding an optical element is formed by the optical surfaces of the upper mold 3A and the lower mold 3B and the inner peripheral surface of the metal barrel mold 2.

  The optical element is molded by the following procedure. The metal upper mold 3A and the lower mold 3B are placed in the metal cylinder mold 2 so that the optical surfaces 3A1 and 3B1 face each other. At this time, the upper die 3A is held at a predetermined height in the first stage by the drive rod 5. The predetermined height in the first stage is a height at which the upper mold 3A is located above the discharge port 8. By holding the upper mold 3A at this height, the molding chamber 9 is formed.

  Next, the polymerizable composition of the present invention containing a thermal polymerization initiator is injected from the injection port 7 and filled into the molding chamber 9. At this time, if the inside of the molding chamber 9 is kept at a negative pressure, it is possible to prevent entrainment of bubbles during injection of the polymerizable composition and air remaining in the molding chamber. The temperature may be adjusted so that the viscosity of the material composition can be easily injected. When the polymerizable composition overflows from the discharge port 8, it is determined that the inside of the molding chamber 9 is filled, and injection of the polymerizable composition is stopped.

  The inlet 7 is closed, and the upper die 3A is pressed downward to the second stage height. At this time, a further excess polymerizable composition flows out from the outlet 8. Next, it is heated by the heating means 4 and cured by a polymerizable reaction. Next, the upper mold 3A is slowly moved downward in accordance with the shrinkage accompanying the curing of the polymerizable composition. By lowering the upper mold 3A in conjunction with the shrinkage, the internal stress of the cured optical element can be reduced. After the polymerizable composition is sufficiently cured, the drive rod 5 is raised to release the upper mold 3A. Next, the release cylinder 6 is moved upward to release the cured product from the lower mold 3B. In this way, a cured product of the polymerizable composition can be taken out as an optical element having a desired shape.

  In FIG. 1, if the optical surfaces 3A1, 3B1 are both spherical, a spherical lens is used. If either or both of the optical surfaces 3A1, 3B1 are aspheric, an aspheric lens is used, whichever of the optical surfaces 3A1, 3B1 is used. Alternatively, if both are diffractive surfaces, a diffractive lens can be manufactured as an optical element.

In addition, when the above-cured optical element is a cured product having sulfur as a repeating unit, the composite optical element has at least one ring structure of a benzene ring, a naphthalene ring, and an anthracene ring in the repeating unit. It can be produced by curing a polymerizable composition forming a single cured product in a state of being placed on the surface of the optical element, and laminating the optical element and the polymerizable composition.
Further, when the previously produced optical element is a single synthetic resin having a cyclic structure of at least one of a benzene ring, a naphthalene ring and an anthracene ring, or a cured product containing a plurality of these, the repeating unit A composite element can be similarly produced using a polymerizable composition that forms a cured product having sulfur.
The composite optical element is a composite optical element in which the interface between different kinds of cured products is a spherical surface, an aspherical surface, a free-form surface, or a diffraction surface.

  Further, a polymerizable composition having a desired composition is placed on the surface of the previously cured optical element by a method such as coating, and a mold is brought into contact with the upper surface so as to have a desired shape. The mold used in this case may be made of metal or glass. However, when the polymerizable composition is cured by irradiating ultraviolet rays from the opposite surface of the previously cured optical element, a glass mold is used. When a metal mold is used, the polymerizable composition is cured by irradiating ultraviolet rays from the side of the previously cured optical element.

By such a method, for example, a composite optical element as shown in FIG. 2 can be manufactured. The composite optical element 10 shown in FIG. 2 has a benzene ring, a naphthalene ring, and an anthracene as the cured product 13 on the surface of the optical element 11 that has been previously prepared, which is a synthetic resin containing sulfur as a repeating unit. It can be produced by laminating a single synthetic resin having any ring structure.
Further, when the previously produced optical element 11 includes a single synthetic resin having a ring structure of at least one of a benzene ring, a naphthalene ring and an anthracene ring or a plurality of these in a repeating unit, the surface is repeatedly formed on the surface. A cured product 13 containing sulfur as a unit is integrally formed.

Hereinafter, a method for manufacturing the composite optical element will be described.
FIG. 3 is a diagram for explaining an example of a composite optical element manufacturing apparatus.
An optical element 11 obtained by curing a synthetic resin containing sulfur as a repeating unit, a single synthetic resin having at least one of a benzene ring, a naphthalene ring and an anthracene ring as a repeating unit, or a polymerizable composition obtained by mixing a plurality of these. Is placed so as to be positioned by the engaging edge 25 of the holding cylinder 23.
Next, when the optical element 11 is a synthetic resin containing sulfur as a repeating unit on the surface 11a of the optical element 11, a cured product having a cyclic structure of any one of a benzene ring, a naphthalene ring, and an anthracene ring in the repeating unit. When the polymerizable composition 12 that can be formed or the optical element 11 is a synthetic resin having at least one of a benzene ring, a naphthalene ring, and an anthracene ring as a repeating unit, the repeating unit contains sulfur. A required amount of the polymerizable composition 12 capable of forming a cured product is discharged by a discharge means (not shown). At this time, it is preferable to adjust the temperature so that the polymerizable composition can easily be discharged.

  A support means 35 is coupled to the support base 21 by a support column 36, and a cylinder 37 is attached to the support means 35. The cylinder 37 lowers the upper mold 3 </ b> A and brings the optical surface 3 </ b> A <b> 1 of the upper mold 3 </ b> A into contact with the polymerizable composition 12 discharged onto the surface 11 </ b> A of the optical element 11. Furthermore, the polymerizable composition 12 is spread in a predetermined shape by continuing to descend. In addition, before extending to a predetermined shape, the lowering of the upper mold 3A is stopped. In this state, the optical element 11 is rotated at least once by operating the motor 27 and rotating the holding cylinder 23.

  Thereafter, the cylinder 37 is operated again, and the upper mold 3A is lowered again. When the layer of the polymerizable composition 12 reaches a desired thickness and diameter and reaches a predetermined shape, the lowering of the upper mold 3A is stopped, and an ultraviolet irradiation device (not shown) is applied from the lower side of the optical element 11. Irradiate with ultraviolet rays.

  As a result, the polymerizable composition between the upper mold 3 </ b> A and the optical element 11 is cured, and a cured product 13 of the polymerizable composition can be formed on the surface 11 </ b> A of the optical element 11. At this time, an optical surface to which the optical surface 3A1 of the upper mold 3A is transferred is formed on the surface of the cured product 13 of the polymerizable composition. A composite optical element having a desired shape can be obtained by releasing the cured product from the optical surface 3A1 of the upper mold 3A from the surface of the cured product 13 of the polymerizable composition.

Example 1
Preparation of Sample 1-1 for Optical Characteristic Evaluation Add 0.2 g of tributylamine as a polymerization initiator to 20 g of bicyclo (2.2.1) -2,3,5,6-tetrathiaheptane and heat to 60 ° C. Sample 1 made of synthetic resin containing sulfur in a repeating unit having a thickness of 1 mm by pouring into a mold made of two glass plates with a temperature and stirring and an interval of 1 mm and heating at 80 ° C. for 1 hour. 1 was produced.

Preparation of Sample 1-2 for Optical Characteristic Evaluation 20 g of N-allylcarbazole was mixed with 0.1 g of bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide as a photoinitiator and heated to 60 ° C. with stirring. Then, it is injected into a mold made of two glass plates with a distance of 1 mm, cured by irradiating 405 nm ultraviolet light under the condition of 200 mW / cm ² intensity of 100 s, and cyclically forming a repeating unit having a thickness of 1 mm. Sample 1-2 made of a synthetic resin having a structure and containing no sulfur was prepared.

Optical property evaluation The obtained sample 1-1 and sample 1-2 were evaluated by the following evaluation method.
(1) Measurement of refractive index The refractive index with respect to the d-line, C-line, F-line, and g-line of the sample was measured using a precision refractometer (KPR-200 manufactured by Shimadzu Device Manufacturing Co., Ltd.). The measurement environment was 20 ° C. and 60% RH.
(2) Calculation of Abbe number νd When the refractive indexes for the obtained d-line, C-line, F-line, and g-line are nd, nC, nF, and ng, respectively, the Abbe number vd is calculated from Equation 2 below. did.
vd = (nd-1) / (nF-nC) Equation 3

(3) Calculation of partial dispersion ratio θgF When the refractive indexes for the d-line, C-line, F-line, and g-line obtained by measurement are nd, nC, nF, and ng, respectively, the partial dispersion ratio θgF is Calculated from Equation 4.
θgF = (ng−nF) / (nF−nC) Equation 4
(4) Calculation of anomalous dispersion ΔθgF According to the above equations 3 and 4, the Abbe number νd and partial dispersion ratio θgF of each cured product are obtained, the Abbe number νd on the horizontal axis, and the partial dispersion ratio θgF on the vertical axis, Among the optical glasses, F7 (νd = 60.5, θgF = 0.547) and K2 (νd = 36.3, θgF = 0.583) are selected as the reference dispersion glass, and the coordinates (νd , ΘgF) are connected by a straight line, and the difference in ordinate (ΔθgF) from the coordinates indicating θgF and νd of the cured product compared with this straight line is defined as anomalous dispersion.
In other words, the relationship between the straight lines connecting the two types of reference glass is expressed by Equation 5 assuming that the Abbe number νd0 and the partial dispersion ratio θgF0. The anomalous dispersion ΔθgF was calculated from Equation 6 where νd was the Appe number of the cured product obtained from Equation 3 and θgF was the partial dispersion ratio of the cured product obtained from Equation 4.
θgFo = −0.0149 × νd0 + 0.637 Equation 5
ΔθgF = θgF−θgF0
= ΘgF − (− 0.0149 × νd + 0.637) Equation 6
(5) Evaluation of transparency The transmittance | permeability of 300 nm-800 nm of each sample was measured using the spectrophotometer (Hitachi High-Technologies U-4100). When the transmittance at 450 nm was 70% or more, it was judged as “good”, and when it was less than that, it was judged as “bad”.

Production of Composite Optical Element A composite optical element as shown in FIG. 2 in which the joint surface and the three surfaces other than the joint surface are spherical surfaces was produced in the ultraviolet curing direction.
First, the biconcave optical element having the curvature radius R1 = 16 mm, the curvature radius R2 = 16 mm, and L3 = 1 mm using the molding apparatus shown in FIG. Produced.
Next, after applying the polymerizable composition used in the preparation of the optical property evaluation sample 1-2 on the obtained optical element using the molding apparatus shown in FIG. After curing by irradiation, the upper mold was raised, and a composite optical element having curvature radii R3 = 26 mm and L4 = 1 mm as shown in FIG. 2 was taken out from the molding apparatus.
The focal length of the obtained composite optical element is −11.6 mm.

Example 2
Preparation of Sample 2-1 for Optical Property Evaluation The polymerizable composition was 20 g of 1,4-bis (β-epithiopropylthiomethyl) benzene, and 0.1 g of triethylamine was used as a polymerization initiator, In the same manner as Sample 1-1 described in Example 1, Sample 2-1 for optical property evaluation made of a synthetic resin containing sulfur as a repeating unit was produced.

Preparation of Sample 2-2 for Evaluation of Optical Properties The polymerizable composition is 20 g of 1-acryloxy-4-methoxynaphthalene, and 0.1 g of bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide is used as a photoinitiator. A synthetic resin having a cyclic structure in the repeating unit and containing no sulfur in the same manner as Sample 1-2 described in Example 1, except that irradiation with ultraviolet rays of 405 nm was performed at an intensity of 100 mW / cm ² for 200 seconds. A sample 2-2 for evaluating optical properties was prepared.
Optical property evaluation The obtained sample 2-1 and sample 2-2 were evaluated in the same manner as the evaluation method described in Example 1, and the results are shown in Table 1.

Production of Composite Optical Element A composite optical element was produced in the same manner as in Example 1 except that Sample 1-1 and Sample 1-2 in Example 1 were changed to Sample 2-1 and Sample 2-2, respectively. The evaluation results are shown in Table 1.
The focal length of the obtained composite optical element is -14.2 mm.

Example 3
Preparation of Sample 3-1 for Optical Characteristic Evaluation The polymerizable composition was 20 g obtained by mixing bis (2-methacryloylthioethyl) sulfide and styrene in a ratio of 7: 3, and 2,2-azobis was used as a polymerization initiator. It consists of a synthetic resin containing sulfur in the repeating unit in the same manner as Sample 1-1 described in Example 1, except that 0.1 g of isobutyronitrile was added, stirred, and heated and polymerized at 60 ° C. for 15 hours. Sample 3-1 for optical property evaluation was produced.

Preparation of Sample 3-2 for Optical Property Evaluation The polymerizable composition was mixed with 9,9-bis [4- (2-acryloyloxyethoxy) phenyl] fluorene and dimethyloltricyclodecane diacrylate in a ratio of 7: 3. 20 g, 0.1 g of bis (2,6-dimethoxybenzoyl) -2,4,4-trimethyl-pentylphosphine oxide and 2-hydroxy-2-methyl-1-phenyl-propan-1-one as a photoinitiator The repeating unit has a cyclic structure in the same manner as Sample 1-2 described in Example 1 except that 0.1 g was used and cured by irradiating UV light of 405 nm with an intensity of 300 mW / cm ² for 70 seconds. A sample 3-2 for evaluating optical properties made of a synthetic resin containing no sulfur was produced.

Optical Property Evaluation The obtained sample 3-1 and sample 3-2 were evaluated in the same manner as the evaluation method described in Example 1, and the results are shown in Table 1.

Production of Composite Optical Element A composite optical element was produced in the same manner as in Example 1 except that Sample 1-1 and Sample 1-2 were changed to Sample 3-1 and Sample 3-2, respectively. The evaluation results are shown in Table 1.
The focal length of the obtained composite optical element is −15.9 mm.

Example 4
Preparation of Sample 4-1 for Optical Property Evaluation The polymerizable composition is 20 g of 1,6-bis (β-epithiopropylthio) hexane, 0.2 g of triethylamine is added as a polymerization initiator, and the mixture is stirred. A sample 4-1 for optical property evaluation made of a synthetic resin containing sulfur as a repeating unit was produced in the same manner as the sample 1-1 described in Example 1 except that the time-hardening reaction was performed.

Preparation of Sample 4-2 for Optical Characteristic Evaluation 20 g of a polymerizable composition in which N- (β-acryloyloxyethyl) carbazole and dimethyloltricyclodecane diacrylate were blended at a mass ratio of 84:16 was used as a photoinitiator. Bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide 0.1 g as follows, heated to 60 ° C. and stirred, and irradiated with 405 nm ultraviolet light at an intensity of 200 mW / cm ² for 100 seconds. A sample 4-2 for optical property evaluation made of a synthetic resin having a cyclic structure in the repeating unit and containing no sulfur was prepared in the same manner as in Sample 1-2 described in Example 1 except for the cured point.
Optical Property Evaluation The obtained sample 4-1 and sample 4-2 were evaluated in the same manner as the evaluation method described in Example 1, and the results are shown in Table 1.

Production of Composite Optical Element A composite optical element was produced in the same manner as in Example 1 except that Sample 1-1 and Sample 1-2 in Example 1 were changed to Sample 4-1 and Sample 4-2, respectively. The evaluation results are shown in Table 1.
The focal length of the obtained composite optical element is -13.4 mm.

Comparative Example 1
Optical characteristics comparison evaluation Preparation of sample comparison 1-1 2,5-dimercaptomethyl-1,4-dithiane 18 g, pentaerythritol tetrakismercaptopropionate 9 g, 1,3-bis (isocyanatomethyl) cyclohexane 23 g, and dimethyltin 0.005 g of dichloride was added, mixed and stirred, and heated at 60 ° C. for 15 hours to obtain a cured product. The refractive index of the cured product was nd = 1.6 and the Abbe number νd = 40.

Optical characteristics comparison evaluation Preparation of sample comparison 1-2 The polymerizable composition is 20 g obtained by mixing methyl methacrylate and styrene at a ratio of 3: 7, and 2,2-azobisisobutyronitrile is used as a polymerization initiator. 1 g was added and stirred, and heated at 60 ° C. for 15 hours to obtain a cured product. The refractive index of the cured product was nd = 1.57, and the Abbe number νd = 34.
The focal length of the obtained composite optical element is −16.0 mm.

  In Examples 1 to 4 of the present invention, a cured product having a high refractive index is obtained, and in a composite optical element made using the same, the optical system is reduced in size even in the same lens shape as compared with the comparative example. It has been found that an optical element having a large power effective for aberration reduction can be obtained.

  As in the present invention, a composite optical element formed from a plurality of synthetic resins has a synthetic resin layer containing sulfur in the repeating unit and a ring structure of any one of a benzene ring, a naphthalene ring, and an anthracene ring in the repeating unit. Since two layers of synthetic resin layers not containing sulfur are adhered and laminated, a composite optical element that is effective in reducing chromatic aberration and other aberrations in the optical system can be provided.

  DESCRIPTION OF SYMBOLS 1 ... Composite optical element shaping | molding apparatus, 2 ... Metal cylinder type | mold, 3A ... Upper mold | type, 3B ... Lower mold | type, 3A1 ... Optical surface, 3B1 ... Optical surface, 4 ... Heating means, 5 ... Drive rod, 6 ... Release cylinder 7 ... Injection port, 8 ... Discharge port, 9 ... Molding chamber, 10 ... Composite optical element, 11 ... Optical element, 11A ... Surface, 12 ... Polymerizable composition, 13 ... Cured product, 21 ... Support base, 23 ... Holding cylinder, 25 ... engaging edge, 27 ... motor, 35 ... support means, 36 ... support column, 37 ... cylinder

Claims (9)

  A synthetic resin layer containing sulfur as a repeating unit and a synthetic resin layer containing a cyclic structure of any one of a benzene ring, a naphthalene ring and an anthracene ring as a repeating unit and not containing sulfur. There is a composite optical element.   The composite optical element according to claim 1, wherein the synthetic resin layer containing sulfur is obtained by polymerizing a polymerizable composition containing an episulfide compound.   The composite optical element according to claim 2, wherein the episulfide compound contains an alkyl episulfide compound.   The refractive index nd of the d-line of the synthetic resin layer containing sulfur in the repeating unit is nd> 1.60, the Abbe number is 40> νd> 30, and the anomalous dispersion θgF is −0.015 ≦ ΔθgF ≦ 0.075. The composite optical element according to claim 1, wherein the composite optical element is provided.   The refractive index nd of the d-line of the synthetic resin layer containing sulfur in the repeating unit is nd> 1.66, the Abbe number is 38> νd> 28, and the anomalous dispersion θgF is −0.015 ≦ ΔθgF ≦ 0.075. The composite optical element according to claim 4, wherein the composite optical element is provided.   The composite optical element according to any one of claims 1 to 5, wherein a transmittance of the synthetic resin layer containing sulfur in the repeating unit at a thickness of 1 mm is 70% or more at 450 nm.   The synthetic resin layer having any one of a benzene ring, a naphthalene ring, and an anthracene ring in the repeating unit, and containing no sulfur in the repeating unit, contains nitrogen in the repeating unit. The composite optical element according to Item.   The composite optical element according to claim 1, wherein the surface on which the synthetic resin is laminated is an aspherical surface.   The composite optical element according to claim 1, wherein the surface on which the synthetic resin is laminated is a diffractive surface.

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