WO2010016377A1

WO2010016377A1 - Optical element and optical pickup device

Info

Publication number: WO2010016377A1
Application number: PCT/JP2009/062965
Authority: WO
Inventors: 大輔渡邉
Original assignee: コニカミノルタオプト株式会社
Priority date: 2008-08-08
Filing date: 2009-07-17
Publication date: 2010-02-11
Also published as: JPWO2010016377A1

Abstract

Provided are an optical element and an optical pickup device which can surely improve the reflection prevention effect by a fluorination process. The optical element has a molded portion molded by a resin material. The resin material contains a resin having an alicyclic hydrocarbon structure, wherein each unit structure has four or more tertiary carbon atoms. The density of the resin is 1.01 g/cm3 or above. The molded portion has, on the surface thereof, a layer containing a resin having the alicyclic hydrocarbon structure in which at least one hydrogen atom is replaced by a fluorine atom.

Description

Optical element and optical pickup device

The present invention relates to an optical element and an optical pickup device.

Conventionally, a resin material having an alicyclic structure has a low water absorption and is preferably used as a material for an optical element. Further, such an optical element is subjected to antireflection treatment from the viewpoint of increasing the transmittance.

Here, as an antireflection method, an antireflection effect is obtained by attaching a vapor deposition film of an inorganic material or by fluorinating the fluorine gas by substituting CH bonds in the resin with CF bonds. A method (for example, refer to Patent Document 1) is known.

Of these, the method of applying a vapor deposition film made of an inorganic material requires a large-scale apparatus, and the film thickness tends to be non-uniform when the surface angle becomes tight. In addition, the adhesion between the inorganic layer (deposited film) and the resin layer (base material) is poor, and film peeling occurs when short-wavelength light such as blue laser is irradiated.

On the other hand, since the method of performing the fluorination treatment is performed in the gas phase, it is considered preferable because a uniform film can be formed regardless of the surface angle.

However, since Patent Document 1 does not disclose the structure of the resin, the antireflection effect cannot be reliably improved by the fluorinated film.

JP 2005-274748 A

An object of the present invention is to provide an optical element and an optical pickup device that can surely improve the antireflection effect by the fluorination treatment.

According to one aspect of the present invention, the optical element of the present invention is an optical element having a molded part molded from a resin material,
The resin material is
A resin having an alicyclic hydrocarbon structure, wherein the number of tertiary carbons in the unit structure is 4 or more, and the density is 1.01 g / cm ³ or more;
The molded part is on the surface,
It has a layer containing a resin in which at least a part of hydrogen constituting the alicyclic hydrocarbon structure is substituted with fluorine.

In this optical element,
It is preferable that an antireflection coating made of an inorganic material is provided on the fluorinated film.

According to another aspect of the present invention, in an optical pickup device,
The optical element of the present invention is provided as an objective lens.

In order to improve the antireflection effect by the fluorination treatment, it is preferable to increase the refractive index difference between the base material (molded part) and the fluorinated film. To increase the refractive index difference, C—H bonds in the base material It is desirable to substitute more C—F bonds.

As a result of diligent research, the present inventors have found that in order to easily cause such a substitution reaction, the carbon bonded with CH in the substrate is a tertiary carbon, that is, in an unstable state. It is considered that carbon is preferable. Further, as the number of tertiary carbons in the substrate increases, the number of C—F bonds increases after the fluorination treatment, and the difference in refractive index from the resin material can be increased. Thought. However, if the tertiary carbon in the substrate is simply increased, the reaction rate of the fluorination treatment increases, resulting in an interface between the resin portion layer that has not been fluorinated and the resin portion layer that has been fluorinated. It turned out that the anti-reflection efficiency deteriorates. Therefore, when the density of the resin material is increased to 1.01 g / cm ³ or more in order to suppress the penetration rate of the fluorine gas, the penetration rate is lowered and the reactivity of the penetrated portion is increased. It has been found that a high fluorinated film can be formed. Furthermore, it has been found that the tertiary carbon number per unit structure is preferably 4 or more in order to increase the difference in refractive index between the substrate and the fluorinated film.

That is, according to the present invention, the surface of the molded part is fluorinated to form a fluorinated film, that is, contains a resin in which at least a part of hydrogen constituting the alicyclic hydrocarbon structure is substituted with fluorine. The resin material of the molding part has an alicyclic hydrocarbon structure, the number of tertiary carbons in the unit structure is 4 or more, and the density is 1.01 g / cm ³ or more. Since the resin is contained, the antireflection effect by the fluorination treatment can be reliably improved.

It is drawing which shows schematic structure of the optical pick-up apparatus used by preferable embodiment of this invention.

Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.
[1] Optical pickup device 30
As shown in FIG. 1, the optical pickup device 30 includes a semiconductor laser oscillator 32 as a light source. The semiconductor laser oscillator 32 emits blue light (blue-violet light) having a specific wavelength (for example, 405 nm) having a wavelength of 380 to 420 nm for BD (Blu-ray Disc). On the optical axis of the blue-violet light emitted from the semiconductor laser oscillator 32, a collimator 33, a beam splitter 34, a ¼ wavelength plate 35, an aperture 36, and an objective lens 37 are arranged in a direction away from the semiconductor laser oscillator 32. Are sequentially arranged.

A sensor lens group 38 and a sensor 39 each including two sets of lenses are sequentially arranged at a position close to the beam splitter 34 and in a direction orthogonal to the optical axis of the blue-violet light described above.
[1-2] Objective lens 37
The objective lens 37 is disposed at a position facing the high-density optical disc D (BD optical disc), and collects blue-violet light emitted from the semiconductor laser oscillator 32 on one surface of the optical disc D. Yes. The objective lens 37 has an image-side numerical aperture NA of 0.7 or more. The objective lens 37 is provided with a two-dimensional actuator 40, and the objective lens 37 is movable on the optical axis by the operation of the two-dimensional actuator 40.

As shown in the enlarged view of FIG. 1, the objective lens 37 is mainly composed of a molding part 50, and a fluorinated film 55 and an antireflection film 60 are formed on the surface 37a.
[1-2.1] Molding unit 50
Among these, the shaping | molding part 50 is shape | molded by the lens shape, and exhibits essential optical functions, such as a condensing function. The molded part 50 is molded from a resin material. The resin material has an alicyclic hydrocarbon structure, the number of tertiary carbons in the unit structure is 4 or more, and the density is 1.01 g / A resin of cm ³ or more is contained as a base material resin.

Here, the unit structure in the present invention refers to a unit structure in a monomer. If the resin is a copolymer, it refers to a unit structure in a monomer having the largest number of tertiary carbons.
[1-2.1A] Resin material of molded part 50 The alicyclic hydrocarbon resin having a tertiary carbon of 4 or more and a density greater than 1.01 g / cm ³ used in the present invention is not particularly limited. Examples thereof include resins represented by the following general formula. As the resin composition, a resin composition having a copolymer resin composed of an α-olefin and a cyclic olefin and a light-resistant stabilizer base material is preferably used.

The cyclic olefin in the copolymer constituting the resin composition is preferably a cyclic olefin represented by the following formula (I) or (II).

In the formula, n is 0 or 1, m is 0 or a positive integer, and k is 0 or 1. When k is 1, the ring represented by k is a 6-membered ring, and when k is 0, this ring is a 5-membered ring.

R ¹ to R ¹⁸ and R ^a and R ^b are each independently a hydrogen atom, a halogen atom or a hydrocarbon group. Here, the halogen atom is a fluorine atom, a chlorine atom, a bromine atom or an iodine atom.

The hydrocarbon group usually includes an alkyl group having 1 to 20 carbon atoms, a halogenated alkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 3 to 15 carbon atoms, or an aromatic hydrocarbon group. . More specifically, examples of the alkyl group include a methyl group, an ethyl group, a propyl group, an isopropyl group, an amyl group, a hexyl group, an octyl group, a decyl group, a dodecyl group, and an octadecyl group. These alkyl groups may be substituted with a halogen atom.

Examples of the cycloalkyl group include a cyclohexyl group, and examples of the aromatic hydrocarbon group include a phenyl group and a naphthyl group. Further, in the general formula (I), R ¹⁵ and R ¹⁶ are R ¹⁷ and R ¹⁸ , R ¹⁵ and R ¹⁷ are R ¹⁶ and R ¹⁸ , R ¹⁵ and R ¹⁸ are R ¹⁶ and R ¹⁷ may be bonded to each other (in cooperation with each other) to form a monocyclic or polycyclic group, and the monocyclic or polycyclic ring thus formed is a double bond You may have. Specific examples of the monocyclic or polycyclic ring formed here include the following.

In the above examples, the carbon atom numbered 1 or 2 represents a carbon atom bonded to R ¹⁵ (R ¹⁶ ) or R ¹⁷ (R ¹⁸ ) in the general formula (I).

R ¹⁵ and R ¹⁶ , or R ¹⁷ and R ¹⁸ may form an alkylidene group. Such alkylidene groups are usually alkylidene groups having 2 to 20 carbon atoms, and specific examples of such alkylidene groups include ethylidene, propylidene and isopropylidene groups.

In the formula, p and q are each independently 0 or a positive integer, and r and s are each independently 0, 1 or 2. R ²¹ to R ³⁹ are each independently a hydrogen atom, a halogen atom, a hydrocarbon group or an alkoxy group.

Here, the halogen atom is the same as the halogen atom in the general formula (I). Examples of the hydrocarbon group generally include an alkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 3 to 15 carbon atoms, and an aromatic hydrocarbon group. More specifically, examples of the alkyl group include a methyl group, an ethyl group, a propyl group, an isopropyl group, an amyl group, a hexyl group, an octyl group, a decyl group, a dodecyl group, and an octadecyl group. These alkyl groups may be substituted with a halogen atom.

Examples of the cycloalkyl group include a cyclohexyl group. Examples of the aromatic hydrocarbon group include an aryl group and an aralkyl group. Specifically, the phenyl group, the tolyl group, the naphthyl group, the benzyl group, and the phenylethyl group. Etc.

Examples of the alkoxy group include a methoxy group, an ethoxy group, and a propoxy group. Here, the carbon atom to which R ²⁹ and R ³⁰ are bonded and the carbon atom to which R ³³ is bonded or the carbon atom to which R ³¹ is bonded are directly or an alkylene group having 1 to 3 carbon atoms. It may be connected via. That is, when the two carbon atoms are bonded via an alkylene group, R ²⁹ and R ³³ or R ³⁰ and ³¹ are combined with each other to form a methylene group (—CH ₂ — ), An ethylene group (—CH ₂ CH ₂ —) or a propylene group (—CH ₂ CH ₂ CH ₂ —).

Further, when r = s = 0, R ³⁵ and R ³² or R ³⁵ and R ³⁹ may be bonded to each other to form a monocyclic or polycyclic aromatic ring. Specifically, when r = s = 0, the following aromatic rings formed by R ³⁵ and R ³² are exemplified.

Here, q is the same as q in the general formula (II). Specific examples of the cyclic olefin represented by the above general formula (I) or (III) include bicyclo-2-heptene derivatives (bicyclohept-2-ene derivatives), tricyclo-3-decene derivatives, tricyclo- 3-undecene derivative, tetracyclo-3-dodecene derivative, pentacyclo-4-pentadecene derivative, pentacyclopentadecadiene derivative, pentacyclo-3-pentadecene derivative, pentacyclo-3-hexadecene derivative, pentacyclo-4-hexadecene derivative, hexacyclo-4 -Heptadecene derivatives, heptacyclo-5-eicosene derivatives, heptacyclo-4-eicosene derivatives, heptacyclo-5-heneicosene derivatives, octacyclo-5-docosene derivatives, nonacyclo-5-pentacocene derivatives, nonacyclo-6- Xacocene derivative, cyclopentadiene-acenaphthylene adduct, 1,4-methano-1,4,4a, 9a-tetrahydrofluorene derivative, 1,4-methano-1,4,4a, 5,10,10a-hexahydroanthracene derivative Etc.

Hereinafter, more specific examples of the cyclic olefin represented by the above general formula (I) or (II) will be shown.

Examples of the α-olefin constituting the copolymer include ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, -Linear α-olefins such as octadecene and 1-eicosene; branched α-olefins such as 4-methyl-1-pentene, 3-methyl-1-pentene and 3-methyl-1-butene. An α-olefin having 2 to 20 carbon atoms is preferable. Such a linear or branched α-olefin may be substituted with a substituent, and may be used alone or in combination of two or more.

Examples of the substituent include various substituents, but typical examples include alkyl, aryl, anilino, acylamino, sulfonamido, alkylthio, arylthio, alkenyl, cycloalkyl, cycloalkenyl, alkynyl, heterocycle, Alkoxy, aryloxy, heterocyclic oxy, siloxy, amino, alkylamino, imide, ureido, sulfamoylamino, alkoxycarbonylamino, aryloxycarbonylamino, alkoxycarbonyl, aryloxycarbonyl, heterocyclic thio, thioureido, hydroxyl and mercapto As well as spiro compound residues, bridged hydrocarbon compound residues, sulfonyl, sulfinyl, sulfonyloxy, sulfamoyl, phosphoryl, carbamoyl, acyl, acyloxy Oxycarbonyl, carboxyl, cyano, nitro, halogen-substituted alkoxy, halogen-substituted aryloxy, pyrrolyl, and the like each group and a halogen atom tetrazolyl, and the like.

The alkyl group preferably has 1 to 32 carbon atoms and may be linear or branched. The aryl group is preferably a phenyl group.

As acylamino group, alkylcarbonylamino group, arylcarbonylamino group; as sulfonamide group, alkylsulfonylamino group, arylsulfonylamino group; alkylthio group, alkyl component in arylthio group, aryl component is the above alkyl group, aryl group Is mentioned.

The alkenyl group preferably has 2 to 23 carbon atoms, and the cycloalkyl group preferably has 3 to 12 carbon atoms, particularly 5 to 7 carbon atoms. The alkenyl group may be linear or branched. The cycloalkenyl group preferably has 3 to 12 carbon atoms, particularly 5 to 7 carbon atoms.

The ureido group is preferably an alkylureido group or arylureido group; the sulfamoylamino group is preferably an alkylsulfamoylamino group or an arylsulfamoylamino group; Is 2-furyl, 2-thienyl, 2-pyrimidinyl, 2-benzothiazolyl, etc .; the saturated heterocyclic ring is preferably a 5- to 7-membered member, specifically tetrahydropyranyl, tetrahydrothiopyranyl, etc .; heterocyclic oxy group Are preferably those having a 5- to 7-membered heterocyclic ring, such as 3,4,5,6-tetrahydropyranyl-2-oxy, 1-phenyltetrazol-5-oxy, etc .; 7-membered heterocyclic thio groups are preferred, such as 2-pyridylthio, 2-benzothiazolylthio, 2,4-diphenoxy-1, , 5-triazole-6-thio, etc .; as siloxy group, trimethylsiloxy, triethylsiloxy, dimethylbutylsiloxy, etc .; as imide group, succinimide, 3-heptadecylsuccinimide, phthalimide, glutarimide, etc .; spiro compound residue As spiro [3.3] heptan-1-yl and the like; as bridged hydrocarbon compound residues, bicyclo [2.2.1] heptan-1-yl, tricyclo [3.3.1.13.7] Examples include decan-1-yl, 7,7-dimethyl-bicyclo [2.2.1] heptan-1-yl, and the like.

As the sulfonyl group, an alkylsulfonyl group, an arylsulfonyl group, a halogen-substituted alkylsulfonyl group, a halogen-substituted arylsulfonyl group, etc .; As a sulfinyl group, an alkylsulfinyl group, an arylsulfinyl group, etc .; As a sulfonyloxy group, an alkylsulfonyloxy group , Arylsulfonyloxy groups, etc .; as sulfamoyl groups, N, N-dialkylsulfamoyl groups, N, N-diarylsulfamoyl groups, N-alkyl-N-arylsulfamoyl groups, etc .; as phosphoryl groups, alkoxy A phosphoryl group, an aryloxyphosphoryl group, an alkylphosphoryl group, an arylphosphoryl group, etc .; examples of the carbamoyl group include an N, N-dialkylcarbamoyl group, an N, N-diarylcarbamoyl group, and an N-alkyl- group. An arylcarbamoyl group, etc .; an acyl group, an alkylcarbonyl group, an arylcarbonyl group, etc .; an acyloxy group, an alkylcarbonyloxy group, etc .; an oxycarbonyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, etc .; a halogen-substituted alkoxy Α-halogen-substituted alkoxy group, etc .; halogen-substituted aryloxy groups, tetrafluoroaryloxy groups, pentafluoroaryloxy groups, etc .; pyrrolyl groups, 1-pyrrolyl, etc .; tetrazolyl groups, such as 1-tetrazolyl, etc. Each group is mentioned.

In addition to the above substituents, groups such as trifluoromethyl, heptafluoro-i-propyl, nonylfluoro-t-butyl, tetrafluoroaryl groups, pentafluoroaryl groups and the like are also preferably used. Furthermore, these substituents may be substituted with other substituents.

The acyclic monomer content in the copolymer of the present invention is preferably 20% by weight or more from the viewpoint of moldability, more preferably 25% or more and 90% or less, and 30% or more and 85% or less. More preferably it is.

The glass transition temperature (Tg) of the polymer or copolymer of the present invention is preferably 80 to 250 ° C., more preferably 90 to 220 ° C., and most preferably 100 to 200 ° C. The number average molecular weight (Mn) is a polystyrene conversion value measured by gel permeation chromatography (GPC), preferably 10,000 to 1,000,000, more preferably 20,000 to 500,000, most preferably Is in the range of 50,000 to 300,000. The molecular weight distribution is preferably 2.0 or less when expressed as a ratio (Mw / Mn) between the above Mn and a polystyrene-equivalent weight average molecular weight (Mw) similarly measured by GPC.

When Mw / Mn is too large, the mechanical strength and heat resistance of the molded product are lowered. In particular, in order to improve mechanical strength, heat resistance, and moldability, Mw / Mn is more preferably 1.8 or less, and particularly preferably 1.6 or less.

The temperature at the time of polymerization is selected from the range of 0 to 200 ° C., preferably 50 to 150 ° C., and the pressure is selected from the range of atmospheric pressure to 100 atm. Moreover, the molecular weight of the produced | generated polymer can be easily adjusted by making hydrogen exist in a polymer zone | band.

The olefin resin of the present invention may be a polymer synthesized from a one-component cyclic monomer, but preferably a copolymer synthesized from two or more cyclic monomers or a cyclic monomer and an acyclic monomer. To be elected. This copolymer may be produced using monomers having 100 or more components, but the mixing of monomers is preferably 10 or less from the viewpoint of production efficiency polymerization stability. More preferred is 5 components or less.

The obtained copolymer may be a crystalline polymer or an amorphous polymer, but preferably an amorphous polymer.

As a method of hydrogenating the carbon-carbon unsaturated bond (including aromatic ring) of the polymer and copolymer of the present invention, a known method can be used. Among them, the hydrogenation rate is increased and hydrogen is added. In order to reduce the polymer chain scission reaction that occurs simultaneously with the addition reaction, a catalyst containing at least one metal selected from nickel, cobalt, iron, titanium, rhodium, palladium, platinum, ruthenium and rhenium is used in an organic solvent. It is preferable to perform a hydrogenation reaction. As the hydrogenation catalyst, either a heterogeneous catalyst or a homogeneous catalyst can be used. The heterogeneous catalyst can be used in the form of a metal or a metal compound or supported on a suitable carrier. Examples of the support include activated carbon, silica, alumina, calcium carbide, titania, magnesia, zirconia, diatomaceous earth, silicon carbide, and the like. The supported amount of the catalyst is a metal content with respect to the total weight of the catalyst, usually 0.01. It is in the range of ˜80% by weight, preferably 0.05 to 60% by weight. The homogeneous catalyst is a catalyst in which a nickel, cobalt, titanium or iron compound and an organometallic compound (for example, an organoaluminum compound or an organolithium compound) are combined, or an organometallic complex catalyst such as rhodium, palladium, platinum, ruthenium or rhenium. Can be used. These hydrogenation catalysts can be used alone or in combination of two or more, and the amount used is usually 0.01 to 100 parts by weight, preferably 0, per 100 parts by weight of the polymer. 0.05 to 50 parts by weight, more preferably 0.1 to 30 parts by weight.

The hydrogenation reaction temperature is usually from 0 to 300 ° C., preferably from room temperature to 250 ° C., particularly preferably from 50 to 200 ° C.

The hydrogen pressure is usually 0.1 MPa to 30 MPa, preferably 1 MPa to 20 MPa, more preferably 2 MPa to 15 MPa. From the viewpoint of heat resistance and weather resistance, the hydrogenation rate of the obtained hydrogenated product is usually 90% or more, preferably 95% or more of the carbon-carbon unsaturated bond of the main chain as measured by 1H-NMR. Preferably it is 97% or more. When the hydrogenation rate is low, optical properties such as transmittance, low birefringence, and thermal stability of the resulting polymer are lowered.

The solvent used in the hydrogenation reaction of the polymer and copolymer of the present invention may be any solvent as long as it dissolves the polymer and copolymer of the present invention and the solvent itself is not hydrogenated. For example, ethers such as tetrahydrofuran, diethyl ether, dibutyl ether and dimethoxyethane, aromatic hydrocarbons such as benzene, toluene, xylene and ethylbenzene, aliphatic hydrocarbons such as pentane, hexane and heptane, cyclopentane, cyclohexane and methylcyclohexane , Aliphatic cyclic hydrocarbons such as dimethylcyclohexane and decalin, and halogenated hydrocarbons such as methylene dichloride, dichloroethane, dichloroethylene, tetrachloroethane, chlorobenzene, and trichlorobenzene. It may be.

The polymer or copolymer hydrogenated product of the present invention can be produced by isolating the polymer or copolymer hydrogenated product from the polymer solution and then dissolving it again in the solvent. It is also possible to employ a method of performing a hydrogenation reaction by adding a hydrogenation catalyst composed of the above organometallic complex and an organoaluminum compound.

After completion of the hydrogenation reaction, the hydrogenation catalyst remaining in the polymer can be removed by a known method. For example, an adsorption method using an adsorbent, a method in which an organic acid such as lactic acid, a poor solvent, and water are added to a solution using a good solvent, and the system is extracted and removed at room temperature or under heating. Acetic acid, citric acid, benzoic acid after contact treatment of a solution or polymer slurry with a basic compound such as trimethylenediamine, aniline, pyridine, ethanediamide, sodium hydroxide, etc. in an atmosphere of nitrogen or hydrogen gas. And a method of washing and removing an acidic compound such as hydrochloric acid after contact treatment.

The method for recovering the polymer hydride from the polymer or copolymer hydrogenated solution of the present invention is not particularly limited, and a known method can be used. For example, the reaction solution is discharged into a poor solvent under stirring to solidify the polymer hydride, and recovered by filtration, centrifugation, decantation, etc., and steam is blown into the reaction solution to remove the polymer hydride. Examples thereof include a steam stripping method for precipitation and a method for directly removing the solvent from the reaction solution by heating.

When the hydrogenation method of the present invention is used, the hydrogenation rate can be easily achieved at 90% or more, and can be 95% or more, particularly 99% or more. The additive is not easily oxidized and becomes an excellent polymer or copolymer hydrogenation.
(Method for preparing resin material)
A method for preparing a resin material (hereinafter also referred to as a resin composition) in the present invention will be described.

The resin composition in the present invention is preferably subjected to a specific processing treatment before the molding step (molding process), and a plasticizer, an antioxidant, and other additives that are usually added to the resin at the stage of the processing treatment. May be added.

Examples of the method for preparing a resin composition in the present invention include a kneading process or a process for obtaining a composition by dissolving a mixture in a solvent, removing the solvent, and drying, and the like. A more preferable preparation method is a kneading process. It is. Moreover, the process used for the mixing | blending of normal resin can be used as a kneading | mixing process. For example, a roll, a Banbury mixer, a twin-screw kneader, a kneader ruder or the like can be used, and a Banbury mixer, a twin-screw kneader, a kneader ruder or the like is preferable. For the purpose of preventing oxidation of the resin, an apparatus capable of kneading in a closed system is preferably used, and more preferably, the kneading process is performed by inert gasification such as nitrogen or argon.
[1-2.1B] Additives to resin material Various additives (also referred to as compounding agents) can be added as necessary during the preparation of the resin composition and the molding process of the resin composition in the present invention. . There are no particular restrictions on the additives, but stabilizers such as antioxidants, heat stabilizers, light stabilizers, weather stabilizers, UV absorbers and near infrared absorbers; resin modifiers such as lubricants and plasticizers Colorants such as dyes and pigments; antistatic agents, flame retardants, fillers and the like. These compounding agents can be used alone or in combination of two or more, and the compounding amount is appropriately selected within a range not impairing the effects described in the present invention.

"Antioxidant"
The antioxidant used in the present invention will be described.

Examples of the antioxidant include phenolic antioxidants, phosphorus antioxidants, sulfur antioxidants, and the like. Among these, phenolic antioxidants, particularly alkyl-substituted phenolic antioxidants are preferable. By blending these antioxidants, it is possible to prevent lens coloring and strength reduction due to oxidative degradation during molding without lowering transparency, heat resistance and the like. These antioxidants can be used alone or in combination of two or more, and the blending amount thereof is appropriately selected within a range not impairing the object of the present invention. The amount is preferably 0.001 to 5 parts by mass, more preferably 0.01 to 1 part by mass with respect to parts.

As the phenolic antioxidant, conventionally known ones can be used, for example, 2-t-butyl-6- (3-t-butyl-2-hydroxy-5-methylbenzyl) -4-methylphenyl acrylate, 2 , 4-di-t-amyl-6- (1- (3,5-di-t-amyl-2-hydroxyphenyl) ethyl) phenyl acrylate and the like, and JP-A Nos. 63-179953 and 1-168643. Acrylate compounds described in Japanese Patent Publication No. 1; octadecyl-3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate, 2,2′-methylene-bis (4-methyl-6-tert-butylphenol) ), 1,1,3-tris (2-methyl-4-hydroxy-5-tert-butylphenyl) butane, 1,3,5-trimethyl-2,4,6-tris (3 -Di-t-butyl-4-hydroxybenzyl) benzene, tetrakis (methylene-3- (3 ', 5'-di-t-butyl-4'-hydroxyphenylpropionate) methane [pentaerythrmethyl-tetrakis ( Alkyl such as 3- (3,5-di-tert-butyl-4-hydroxyphenylpropionate)], triethylene glycol bis (3- (3-tert-butyl-4-hydroxy-5-methylphenyl) propionate) Substituted phenol compounds; 6- (4-hydroxy-3,5-di-t-butylanilino) -2,4-bisoctylthio-1,3,5-triazine, 4-bisoctylthio-1,3,5 -Triazine, 2-octylthio-4,6-bis- (3,5-di-t-butyl-4-oxyanilino) -1,3,5-triazine Azine group-containing phenolic compound; and the like.

The phosphorus antioxidant is not particularly limited as long as it is usually used in the general resin industry. For example, triphenyl phosphite, diphenylisodecyl phosphite, phenyl diisodecyl phosphite, tris (nonylphenyl) Phosphite, tris (dinonylphenyl) phosphite, tris (2,4-di-t-butylphenyl) phosphite, 10- (3,5-di-t-butyl-4-hydroxybenzyl) -9,10 Monophosphite compounds such as -dihydro-9-oxa-10-phosphaphenanthrene-10-oxide; 4,4'-butylidene-bis (3-methyl-6-tert-butylphenyl-di-tridecyl phosphite ), 4,4′isopropylidene-bis (phenyl-di-alkyl (C12-C15) phosphite) Like diphosphite compounds such as. Among these, monophosphite compounds are preferable, and tris (nonylphenyl) phosphite, tris (dinonylphenyl) phosphite, tris (2,4-di-t-butylphenyl) phosphite and the like are particularly preferable.

Examples of the sulfur-based antioxidant include dilauryl 3,3-thiodipropionate, dimyristyl 3,3′-thiodipropionate, distearyl 3,3-thiodipropionate, lauryl stearyl 3,3-thiodiprote. Pionate, pentaerythritol-tetrakis- (β-lauryl-thio-propionate, 3,9-bis (2-dodecylthioethyl) -2,4,8,10-tetraoxaspiro [5,5] undecane It is done.
<Light resistance stabilizer>
The light-resistant stabilizer used in the present invention will be described.

Examples of the light-resistant stabilizer include benzophenone-based light-resistant stabilizer, benzotriazole-based light-resistant stabilizer, hindered amine-based light-resistant stabilizer, etc., but in the present invention, from the viewpoint of lens transparency, color resistance, etc., hindered amine-based It is preferable to use a light-resistant stabilizer. Among hindered amine light-resistant stabilizers (hereinafter referred to as HALS), those having a polystyrene-equivalent Mn measured by GPC using THF as a solvent are preferably 1000 to 10,000, more preferably 2000 to 5000, Those of 2800 to 3800 are particularly preferred. If Mn is too small, when HALS is blended by heat-melting and kneading into a block copolymer, a predetermined amount cannot be blended due to volatilization, foaming or silver streak occurs during heat-melt molding such as injection molding, etc. Processing stability decreases. Further, when the lens is used for a long time with the lamp turned on, a volatile component is generated as a gas from the lens. Conversely, if Mn is too large, the dispersibility in the block copolymer is lowered, the transparency of the lens is lowered, and the effect of improving light resistance is reduced. Therefore, in the present invention, a lens having excellent processing stability, low gas generation and transparency can be obtained by setting the HALS Mn within the above range.

Specific examples of such HALS include N, N ′, N ″, N ′ ″-tetrakis- [4,6-bis- {butyl- (N-methyl-2,2,6,6-tetra Methylpiperidin-4-yl) amino} -triazin-2-yl] -4,7-diazadecane-1,10-diamine, dibutylamine and 1,3,5-triazine and N, N′-bis (2,2 , 6,6-Tetramethyl-4-piperidyl) butylamine, poly [{(1,1,3,3-tetramethylbutyl) amino-1,3,5-triazine-2,4-diyl } {(2,2,6,6-tetramethyl-4-piperidyl) imino} hexamethylene {(2,2,6,6-tetramethyl-4-piperidyl) imino}], 1,6-hexanediamine- N, N'-bis (2,2,6,6-tetra Til-4-piperidyl) and morpholine-2,4,6-trichloro-1,3,5-triazine, poly [(6-morpholino-s-triazine-2,4-diyl) (2 , 2,6,6, -tetramethyl-4-piperidyl) imino] -hexamethylene [(2,2,6,6-tetramethyl-4-piperidyl) imino]] and the like, the piperidine ring is interposed via the triazine skeleton. A plurality of high molecular weight HALS bonded to each other; a polymer of dimethyl succinate and 4-hydroxy-2,2,6,6-tetramethyl-1-piperidineethanol, 1,2,3,4-butanetetracarboxylic acid and 1 2,2,6,6-pentamethyl-4-piperidinol and 3,9-bis (2-hydroxy-1,1-dimethylethyl) -2,4,8,10-tetraoxaspiro [5,5] un Of a mixed ester of cans, piperidine ring linked to a high molecular weight HALS, and the like via an ester bond.

Among these, polycondensates of dibutylamine, 1,3,5-triazine and N, N′-bis (2,2,6,6-tetramethyl-4-piperidyl) butylamine, poly [{(1, 1,3,3-tetramethylbutyl) amino-1,3,5-triazine-2,4-diyl} {(2,2,6,6-tetramethyl-4-piperidyl) imino} hexamethylene {(2 , 2,6,6-tetramethyl-4-piperidyl) imino}], a polymer of dimethyl succinate and 4-hydroxy-2,2,6,6-tetramethyl-1-piperidineethanol and the like. 5,000 to 5,000 are preferred.

The blending amount of the resin material in the present invention is preferably 0.01 to 20 parts by mass, more preferably 0.02 to 15 parts by mass, and particularly preferably 0.05 to 10 parts by mass with respect to 100 parts by mass of the polymer. Part. If the amount added is too small, the effect of improving light resistance cannot be obtained sufficiently, and coloring occurs when used outdoors for a long time. On the other hand, when the blending amount of HALS is too large, a part of the HALS is generated as a gas, or the dispersibility in the resin is lowered, so that the transparency of the lens is lowered.

In addition, by blending the resin composition in the present invention with a compound having the lowest glass transition temperature of 30 ° C. or less, the properties such as transparency, heat resistance and mechanical strength are not deteriorated for a long time. Can prevent cloudiness in high temperature and high humidity environment.

That is, in the present invention, there is provided a resin composition comprising at least one compounding agent selected from the group consisting of the resin composition of the present invention and (1) a soft polymer and (2) an alcoholic compound. The By blending these compounding agents, it is possible to prevent white turbidity in a high temperature and high humidity environment for a long time without degrading various properties such as transparency, low water absorption, and mechanical strength.

Among these, (1) a soft polymer and (2) an alcoholic compound are excellent in the effect of preventing white turbidity in a high temperature and high humidity environment and the transparency of the resulting resin composition.

(1) Soft polymer The soft polymer used in the present invention is usually a polymer having a Tg of 30 ° C. or lower. When a plurality of Tg are present, at least the lowest Tg is preferably 30 ° C. or lower. .

Specific examples of these soft polymers include, for example, liquid polyethylene, polypropylene, poly-1-butene, ethylene / α-olefin copolymers, propylene / α-olefin copolymers, and ethylene / propylene / diene copolymers. (EPDM), olefinic soft polymers such as ethylene / propylene / styrene copolymers, isobutylene soft polymers such as polyisobutylene, isobutylene / isoprene rubber, isobutylene / styrene copolymers; polybutadiene, polyisoprene, butadiene / styrene Random copolymer, isoprene / styrene random copolymer, acrylonitrile / butadiene copolymer, acrylonitrile / butadiene / styrene copolymer, butadiene / styrene / block copolymer, styrene / butadiene / styrene / block Copolymer, isoprene / styrene block copolymer, diene soft polymer such as styrene / isoprene / styrene block copolymer, silicon-containing soft polymer such as dimethylpolysiloxane, diphenylpolysiloxane, dihydroxypolysiloxane, etc. Polymers such as polybutyl acrylate, polybutyl methacrylate, polyhydroxyethyl methacrylate, polyacrylamide, polyacrylonitrile, soft polymers composed of α, β-unsaturated acids such as butyl acrylate / styrene copolymer, polyvinyl alcohol, polyvinyl acetate, Soft polymers composed of unsaturated alcohols such as polyvinyl stearate and vinyl acetate / styrene copolymers and amines or acyl derivatives or acetals thereof, ethylene oxide, polypropylene oxide, Epoxy soft polymers such as lorhydrin rubber, fluorinated soft polymers such as vinylidene fluoride rubber, tetrafluoroethylene-propylene rubber, natural rubber, polypeptide, protein, polyester thermoplastic elastomer, vinyl chloride heat Other soft polymers such as a plastic elastomer and a polyamide-based thermoplastic elastomer can be used. These soft polymers may have a cross-linked structure or may have a functional group introduced by a modification reaction.

Among the above-mentioned soft polymers, diene-based soft polymers are preferable, and hydrides obtained by hydrogenating carbon-carbon unsaturated bonds of the soft polymers are particularly excellent in terms of rubber elasticity, mechanical strength, flexibility, and dispersibility.

(2) Alcoholic Compound The alcoholic compound is a compound having at least one non-phenolic hydroxyl group in the molecule, and preferably has at least one hydroxyl group and at least one ether bond or ester bond. Specific examples of such compounds include, for example, dihydric or higher polyhydric alcohols, more preferably trihydric or higher polyhydric alcohols, and even more preferably one of the hydroxyl groups of a polyhydric alcohol having 3 to 8 hydroxyl groups is an ether. Examples thereof include alcoholic ether compounds and alcoholic ester compounds that have been converted into or esterified.

Examples of the dihydric or higher polyhydric alcohol include polyethylene glycol, glycerol, trimethylolpropane, pentaerythritol, diglycerol, triglycerol, dipentaerythritol, 1,6,7-trihydroxy-2,2-di (hydroxy). Methyl) -4-oxoheptane, sorbitol, 2-methyl-1,6,7-trihydroxy-2-hydroxymethyl-4-oxoheptane, 1,5,6-trihydroxy-3-oxohexanepentaerythritol, tris (2-Hydroxyethyl) isocyanurate and the like can be mentioned, and in particular, a polyhydric alcohol having a valence of 3 or more, more preferably a polyhydric alcohol having 3 to 8 hydroxyl groups. In the case of obtaining an alcoholic ester compound, glycerol, diglycerol, triglycerol or the like capable of synthesizing an alcoholic ester compound containing α, β-diol is preferable.

Examples of such alcoholic compounds include glycerol monostearate, glycerol monolaurate, glycerol monobehenate, diglycerol monostearate, glycerol distearate, glycerol dilaurate, pentaerythritol monostearate, and pentaerythritol monolaurate. , Pentaerythritol monobeherate, pentaerythritol distearate, pentaerythritol dilaurate, pentaerythritol tristearate, dipentaerythritol distearate, and the like; 3- (octyloxy) -1,2-propane Diol, 3- (decyloxy) -1,2-propanediol, 3- (lauryloxy) -1,2-propanediol, 3- (4-nonylpheny Of oxy) -1,2-propanediol, 1,6-dihydrooxy-2,2-di (hydroxymethyl) -7- (4-nonylphenyloxy) -4-oxoheptane, p-nonylphenyl ether and formaldehyde Alcoholic ether compounds obtained by reaction of condensates with glycidol, alcoholic ether compounds obtained by reaction of condensates of p-octylphenyl ether and formaldehyde with glycidol, condensates of p-octylphenyl ether and dicyclopentadiene and glycidol And alcoholic ether compounds obtained by the above reaction. These polyhydric alcohol compounds are used alone or in combination of two or more. The molecular weight of these polyhydric alcoholic compounds is not particularly limited, but those having a molecular weight of usually 500 to 2000, preferably 800 to 1500, have little decrease in transparency.

(3) Organic or inorganic filler As the organic filler, ordinary organic polymer particles or crosslinked organic polymer particles can be used. For example, polyolefins such as polyethylene and polypropylene; halogen-containing materials such as polyvinyl chloride and polyvinylidene chloride Vinyl polymers; polymers derived from α, β-unsaturated acids such as polyarylate and polymethacrylate; polymers derived from unsaturated alcohols such as polyvinyl alcohol and polyvinyl acetate; polyethylene oxide or bisglycidyl ether Polymers derived from: aromatic condensation polymers such as polyphenylene oxide, polycarbonate and polysulfone; polyurethanes; polyamides; polyesters; aldehyde / phenolic resins; natural polymer compound particles or crosslinked particles It can gel.

Examples of the inorganic filler include Group 1 element compounds such as lithium fluoride and borax (sodium borate hydrate); Group 2 element compounds such as magnesium carbonate, magnesium phosphate, calcium carbonate, strontium titanate, and barium carbonate; Titania), Group 4 element compounds such as titanium monoxide; Group 6 element compounds of molybdenum dioxide and molybdenum trioxide; Group 7 element compounds such as manganese chloride and manganese acetate; Group 8-10 elements compounds such as cobalt chloride and cobalt acetate Group 11 element compounds such as cuprous iodide; Group 12 element compounds such as zinc oxide and zinc acetate; Group 13 such as aluminum oxide (alumina), aluminum fluoride, aluminosilicate (alumina silicate, kaolin, kaolinite) Elemental compounds; silicon oxide (silica, silica gel), graphite Carbon, graphite, Group 14 element compound such as glass; kernal stones, kainite, mica (mica, Kin'unmo) include particles of natural minerals, such as Bairosu ore.

The compounding amount of the compounds (1) to (3) is determined by the combination of the alicyclic hydrocarbon copolymer and the compound to be compounded. In general, if the compounding amount is too large, the glass transition temperature of the composition and the transparency The properties are greatly reduced, making it unsuitable for use as an optical material. Moreover, if there are too few compounding quantities, the cloudiness of a molding may be produced under high temperature and high humidity. The blending amount is usually 0.01 to 10 parts by weight, preferably 0.02 to 5 parts by weight, particularly preferably 0.05 to 2 parts by weight with respect to 100 parts by weight of the alicyclic hydrocarbon copolymer. It mixes in the ratio. When the blending amount is too small, the effect of preventing white turbidity in a high temperature and high humidity environment cannot be obtained, and when the blending amount is too large, the heat resistance and transparency of the molded product are lowered.

<Other ingredients>
In the resin composition in the present invention, if necessary, as other compounding agents, ultraviolet absorbers, light stabilizers, near infrared absorbers, coloring agents such as dyes and pigments, lubricants, plasticizers, antistatic agents, A fluorescent brightening agent or the like can be blended, and these can be used alone or in admixture of two or more.
[1-2.2] Fluorinated film 55
The fluorinated film 55 is a layer formed by performing a fluorination process on the molded part 50, and has a function of reducing the surface reflectance of the objective lens 37. The refractive index of the fluorinated film 55 with respect to d-line is 1.35 to 1.45, and the value of the refractive index can be measured by the surface reflectance. The layer thickness of the fluorinated film 55 (thickness from the surface 37a to the inside of the molded part 50) is preferably 10 to 5000 nm. When the layer thickness exceeds 5000 nm, the influence of interference fringes greatly depends on the wavelength of light, and even if the antireflection film 60 is formed thereon, it becomes difficult to exert its function, and conversely, the layer thickness is less than 10 nm. This is because it is difficult to sufficiently exert the function of the fluorinated film 55.
[1-2.3] Antireflection film 60
The antireflection film 60 is made of an inorganic material and basically has a two-layer structure. A first layer 61 is formed directly on the fluorinated film 55, and a second layer 62 is formed thereon.

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

In the objective lens 37, the first layer 61 and the second layer 62 may be alternately stacked on the first layer 61 and the second layer 62, and the antireflection film 60 may have a 2-7 layer structure as a whole. In this case, the layer in direct contact with the fluorinated film 55 may be a layer of high refractive index material (first layer 61) or a layer of low refractive index material (second layer), depending on the type of the molded part 50. Layer 62). In the present embodiment, the layer that is in direct contact with the fluorinated film 55 is a layer of a high refractive index material.

In the objective lens 37, the fluorinated film 55 and the antireflection film 60 are also formed on the back surface 37b in the same manner as the fluorinated film 55 and the antireflection film 60 are formed on the front surface 37a. The fluorinated film 55 and the antireflection film 60 are formed on both the front surface 37a and the back surface 37b. However, the objective lens 37 may not have the antireflection film 60.
[1-2.4] Method for Manufacturing Objective Lens 37 Next, a method for manufacturing the objective lens 37 will be described.

First, the above resin material is injection-molded on a mold under a certain condition to form a molded part 50 having a predetermined shape. Thereafter, a fluorination treatment is performed on the molding unit 50 to form a fluorinated film 55 on the molding unit 50.

In the fluorination treatment, the molded part 50 is exposed to a fluorine gas atmosphere, and a fluorinated film 55 is formed on the surface thereof. Thereby, the refractive index of the polymer material (resin) can be lowered, and the surface reflectance of the objective lens 37 can be lowered.

By appropriately selecting the fluorine gas concentration in the fluorine gas atmosphere and the temperature and time of exposure to the fluorine gas atmosphere, the fluorination rate and the film thickness of the fluorinated film 55 can be arbitrarily controlled, and the surface reflectance at a desired wavelength. Can be reduced.

Here, the fluorine gas atmosphere means being covered with a gas containing fluorine gas, and includes being covered with a mixed gas of fluorine gas and an inert gas such as nitrogen or argon.

Further, the concentration of the fluorine gas in the fluorine gas atmosphere can be appropriately selected according to the desired refractive index and the thickness of the fluorinated film 55.

Further, the molding part 50 is not particularly limited as long as it is a polymer composed of carbon and hydrogen as a constituent element of the resin and is a polymer composed of carbon and hydrogen in addition to the above example.

In addition, the constituent element of the additive whose addition amount is 5% or less with respect to the total weight such as an antioxidant, an ultraviolet absorber, and a plasticizer added to the molded part 50 may be other than carbon and hydrogen. .

Further, even when a polymerization auxiliary material such as a catalyst or a reaction terminator used in manufacturing the molded part 50 remains, if the residual amount is less than 1% with respect to the total weight, its constituent elements Is not limited to carbon and hydrogen.

In the present embodiment, the molded part 50 is not particularly limited as long as the above conditions are satisfied. However, the above-described resin can be used in consideration of high transparency, high heat resistance, low water absorption, high purity, and low birefringence. More preferred is a polymer of the material.

When this polymer is exposed to fluorine gas of various concentrations diluted with nitrogen gas, for example, at a predetermined temperature and for a predetermined time, fluorine is gradually introduced into the molecule from the surface to the inside of the polymer material. The fluorine content of the material will increase.

The penetration depth of fluorine from the material surface and the fluorine content in the material after fluorination treatment vary depending on the concentration of fluorine gas during the fluorination treatment, the fluorination treatment temperature, and the fluorination treatment time.

There are no particular restrictions on these conditions, but when the fluorine concentration is high, the treatment time is long, the treatment temperature is high, the penetration depth of fluorine becomes deep, and the fluorine of the polymer material after fluorination treatment The content rate becomes high.

Since the refractive index of the fluorinated portion decreases as the fluorine content increases, the low-refractive fluorinated film 55 having a desired thickness can be formed by appropriately selecting the fluorine concentration, processing temperature, and processing time. Is possible.

However, if the fluorine concentration is extremely increased or the fluorination treatment is performed at an extremely high temperature for a long time, the molecule deteriorates. Therefore, the normal fluorination treatment conditions are a fluorine concentration of 1 ppm to 25% and a treatment temperature of 0. A treatment time of up to 100 ° C. and a treatment time of 0.1 seconds to 120 minutes is preferred.

Thereafter, an antireflection film 60 is formed on the fluorinated film 55. Specifically, the first layer 61 is formed using a vapor deposition source that constitutes the first layer 61. For example, when a (Ta ₂ O ₅ + 5% TiO ₂ ) film is formed as the first layer 61, OA600 manufactured by OPTRAN can be used as the evaporation source and the evaporation source may be evaporated by electron gun heating. During vapor deposition, it is preferable to form a film while introducing O ₂ gas up to a pressure of 1.0 × 10 ⁻² Pa inside the vacuum vapor deposition apparatus and controlling the vapor deposition rate at 5 Å / sec. Then, the film forming temperature (temperature in the vapor deposition apparatus) is maintained within an appropriate temperature range.

Thereafter, in order to form the first layer 61 on the opposite surface of the molding portion 50, the molding portion 50 is reversed by the reversing mechanism inside the vapor deposition apparatus, and the first layer 61 is also formed on the opposite surface in the same manner as described above. (The same applies to the film formation on the back surface of the second layer 62.)

Thereafter, the second layer 62 is formed on the first layer 61 using the vapor deposition source constituting the second layer 62. For example, when a SiO ₂ film is formed as the second layer 62, O ₂ gas is introduced up to a pressure of 1.0 × 10 ⁻² Pa inside the vacuum vapor deposition apparatus, and the vapor deposition rate is controlled to 5 liters / sec. It is better to form the film while doing so. Then, the film forming temperature (temperature in the vapor deposition apparatus) is maintained within an appropriate temperature range.

The objective lens 37 is manufactured by the above process.
[2] Operation of Optical Pickup Device 30 Next, the operation of the optical pickup device 30 will be described.

Blue-violet light is emitted from the semiconductor laser oscillator 32 during an operation of recording information on the optical disc D or an operation of reproducing information recorded on the optical disc D. The emitted blue-violet light is transmitted through the collimator 33 and collimated into infinite parallel light, then transmitted through the beam splitter 34 and transmitted through the quarter wavelength plate 35. Furthermore, after passing through the blue-violet light aperture 36 and the objective lens 37, forms a converged spot on an information recording surface D ₂ through the protective substrate D ₁ of the optical disc D.

Violet light that formed the concentrated light spot is modulated by the information recording surface D ₂ of the optical disk D by the information bits, is reflected by the information recording surface D _2. Then, the reflected light is sequentially transmitted through the objective lens 37 and the diaphragm 36, the polarization direction is changed by the quarter wavelength plate 35, and the reflected light is reflected by the beam splitter 34. Thereafter, the reflected light passes through the sensor lens group 38 to be given astigmatism, is received by the sensor 39, and finally is photoelectrically converted by the sensor 39 to become an electrical signal.

Thereafter, such an operation is repeatedly performed, and the operation of recording information on the optical disc D and the operation of reproducing information recorded on the optical disc D are completed.

According to the above embodiment, the surface of the molded part 50 is fluorinated to form the fluorinated film 55, the resin material of the molded part 50 has an alicyclic hydrocarbon structure, and has a unit structure. Since the resin contains a resin having a tertiary carbon number of 4 or more and a density of 1.01 g / cm ³ or more, the antireflection effect by the fluorination treatment can be reliably improved.

Further, since the antireflection film 60 is formed on the fluorinated film 55, the antireflection effect can be further improved.

In the above embodiment, the optical element according to the present invention has been described as the objective lens 37, but other types and applications of optical elements may be used.

Hereinafter, the optical element according to the present invention will be described more specifically by giving examples and comparative examples. However, the present invention is not limited to the examples.
(1) Production of Samples As examples and comparative examples of the present invention, samples as shown in Tables 1 and 2 below were produced. Hereinafter, each sample will be specifically described.

(1.1) Example 1
100 parts by mass of a random copolymer of ethylene and bicyclo [2,2,1] hept-2-ene, 0.5 parts by mass of pentaerythritol distearate as a surfactant, and pentaerythritol tetrakis [ 0.3 parts by mass of 3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate] was kneaded with a biaxial kneader to obtain “resin material 1”. The number of tertiary carbons per unit structure of the base resin in “resin material 1” was 4, and the density of “resin material 1” was measured to be 1.04 g / cm ³ .

This “resin material 1” was dried at 70 ° C. for 6 hours to remove moisture, and then with an injection molding machine, the cylinder temperature was 280 ° C., the mold temperature was 80 ° C., the injection speed was 30 mm / sec, and the injection pressure was 80 MPa. The plate was formed.

Next, the plate is exposed to an atmosphere of 1.1 atm, normal temperature, and F ₂ gas concentration of 15% for 15 minutes to subject the plate to fluorination treatment. Samples of Here, the film thickness of the obtained fluorinated film was 100 nm.
(1.2) Example 2
Ethylene and tetracyclo ^[4,4,0,1 ^{2,5, 1 7,10]} dodeca-3 random copolymer 100 parts by weight of the ene, pentaerythritol distearate 0.5 part by weight of a surfactant And 0.3 parts by mass of pentaerythritol tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate] as a stabilizer were kneaded in a biaxial kneader “resin material 2 " The number of tertiary carbons per unit structure of the base resin in this “resin material 2” was 8, and the density of “resin material 2” was measured to be 1.04 g / cm ³ .

This “resin material 2” was dried at 70 ° C. for 6 hours to remove moisture, and then with an injection molding machine, the cylinder temperature was 280 ° C., the mold temperature was 80 ° C., the injection speed was 30 mm / sec, and the injection pressure was 80 MPa. The plate was formed.

Next, the plates 1.1 atmospheres, room temperature, by exposing F ₂ gas concentration 5% 16 minutes under an atmosphere of, performs a fluorination treatment with respect to the plate, the resulting plate "Example 2" Samples of Here, the film thickness of the obtained fluorinated film was 100 nm.
(1.3) Comparative Example 1
The inside of the stainless steel reactor equipped with a stirrer was sufficiently dried and purged with nitrogen. Thereafter, 300 parts by mass of dehydrated cyclohexane, 60 parts by mass of styrene and 0.38 parts by mass of dibutyl ether were charged into the reactor, and the n-butyllithium solution (15% hexane solution) 0 was added while stirring them at 60 ° C. .36 parts by mass was added to initiate the polymerization reaction.

Polymerization reaction is performed for 1 hour, and then the reaction solution is mixed with 8 parts by mass of styrene, 12 parts by mass of isoprene, and 0.8 parts by mass of 1,2,2,6,6-pentamethyl-4-piperidylmethacrylate. A monomer was added and the polymerization reaction was further performed for 1 hour, and then 0.2 parts by mass of isopropyl alcohol was added to the reaction solution to stop the reaction.

Next, 300 parts by mass of the above polymerization reaction solution was transferred to a pressure-resistant reactor equipped with a stirrer, and as a hydrogenation catalyst, a silica-alumina supported nickel catalyst (manufactured by JGC Kagaku Kogyo Co., Ltd .: E22U, nickel supported amount 60). %) 10 parts by mass were added and mixed. The inside of the reactor was replaced with hydrogen gas, hydrogen was further supplied while stirring the solution, the temperature was set to 160 ° C., and then a hydrogenation reaction was performed at a pressure of 4.5 MPa for 8 hours.

After completion of the reaction, the reaction solution was filtered to remove the hydrogenation catalyst, 800 parts by mass of cyclohexane was added for dilution, and then the reaction solution was poured into 3500 parts by mass of isopropanol to precipitate a copolymer. Thereafter, this copolymer was filtered out and dried under reduced pressure at 80 ° C. for 48 hours to obtain “resin material 3”. In this “resin material 3”, the number of tertiary carbons per unit structure of the base resin was two, and the density of “resin material 3” was measured to be 0.94 g / cm ³ .

This “resin material 3” was dried at 70 ° C. for 6 hours to remove moisture, and then with an injection molding machine, the cylinder temperature was 280 ° C., the mold temperature was 80 ° C., the injection speed was 30 mm / sec, and the injection pressure was 80 MPa. The plate was formed.

The plate is exposed to an atmosphere of 1.1 atm, normal temperature, and F ₂ gas concentration of 5% for 10 minutes to subject the plate to fluorination treatment. did. Here, the film thickness of the obtained fluorinated film was 100 nm.
(1.4) Comparative Example 2
The inside of the stainless steel reactor equipped with a stirrer was sufficiently dried and purged with nitrogen. Thereafter, 300 parts by mass of dehydrated cyclohexane, 60 parts by mass of 2,4-dimethylstyrene and 0.38 parts by mass of dibutyl ether were charged into the reactor. While stirring at 60 ° C., an n-butyllithium solution (15% Containing hexane solution) 0.36 parts by mass was added to initiate the polymerization reaction.

Polymerization reaction was performed for 1 hour, and then 8 parts by mass of 2,4-dimethylstyrene, 12 parts by mass of isoprene and 1,2,2,6,6-pentamethyl-4-piperidyl methacrylate 0.8 were added to the reaction solution. A mixed monomer consisting of parts by mass was added, and a polymerization reaction was further performed for 1 hour, and then 0.2 parts by mass of isopropyl alcohol was added to the reaction solution to stop the reaction.

After completion of the reaction, the reaction solution was filtered to remove the hydrogenation catalyst, 800 parts by mass of cyclohexane was added for dilution, and then the reaction solution was poured into 3500 parts by mass of isopropanol to precipitate a copolymer. Thereafter, this copolymer was filtered out and dried under reduced pressure at 80 ° C. for 48 hours to obtain “resin material 4”. The number of tertiary carbons per unit structure of the base resin in this “resin material 4” was 4, and the density of “resin material 4” was measured to be 0.95 g / cm ³ .

This “resin material 4” was dried at 70 ° C. for 6 hours to remove moisture, and then with an injection molding machine, the cylinder temperature was 280 ° C., the mold temperature was 80 ° C., the injection speed was 30 mm / sec, and the injection pressure was 80 MPa. The plate was formed.

The plates 1.1 atmospheres, room temperature, by exposure for 10 minutes in an atmosphere of F ₂ gas concentration 5%, performed fluorination process on the plate, the resulting plate and samples of "Comparative Example 2" did. Here, the film thickness of the obtained fluorinated film was 100 nm.
(1.5) Comparative Example 3
100 parts by mass of bicyclo [2,2,1] hept-2-ene and 7.6 parts by mass of 1-hexene are dissolved in 300 parts by mass of toluene. Here, 2 parts by mass of diethylaluminum chloride solution and 0% of tungsten hexachloride are dissolved. 0.003 part by mass was added, and the mixture was stirred at 80 ° C. for 3 hours. After stirring, a large amount of methanol was put into the mixed solution to be solidified, and the solidified polymer was dried.

100 parts by mass of the obtained polymer was dissolved in tetrahydrofuran, 10 parts by mass of palladium / alumina was added thereto as a hydrogenation catalyst, and a hydrogenation reaction was carried out while heating and stirring at 170 ° C. under a pressure of 4 MPa for 4 hours. Thereafter, the catalyst was filtered to obtain “resin material 5”. In this “resin material 5”, the number of tertiary carbons per unit structure of the base resin was two, and the density of “resin material 5” was measured to be 1.01 g / cm ³ .

Resin material 5 is obtained by hydrogenating a polymer formed by ring-opening metathesis polymerization, and there are two tertiary carbons per unit structure.

This “resin material 5” was dried at 70 ° C. for 6 hours to remove moisture, and then with an injection molding machine, the cylinder temperature was 280 ° C., the mold temperature was 80 ° C., the injection speed was 30 mm / sec, and the injection pressure was 80 MPa, and the thickness was 3 mm. The plate was formed.

Next, the plates 1.1 atmospheres, room temperature, by exposure for 12 minutes under an atmosphere of F ₂ gas concentration 5%, performed fluorination process on the plate, the resulting plate "Comparative Example 3" Samples of Here, the film thickness of the obtained fluorinated film was 100 nm.
(1.6) Comparative Example 4
100 parts by mass of 5-methyl-bicyclo [2,2,1] hept-2-ene and 7.6 parts by mass of 1-hexene are dissolved in 300 parts by mass of toluene, and 2 parts by mass of diethylaluminum chloride solution, 0.003 parts by mass of tungsten chloride was added and stirred at 80 ° C. for 3 hours. After stirring, a large amount of methanol was put into the mixed solution to be solidified, and the solidified polymer was dried.

100 parts by mass of the obtained polymer was dissolved in tetrahydrofuran, 10 parts by mass of palladium / alumina was added thereto as a hydrogenation catalyst, and a hydrogenation reaction was carried out while heating and stirring at 170 ° C. under a pressure of 4 MPa for 4 hours. Thereafter, the catalyst was filtered to obtain “resin material 6”. The number of tertiary carbons per unit structure of the base resin in this “resin material 6” was 3, and the density of “resin material 6” was measured to be 1.01 g / cm ³ .

In the resin material 6, the 5-position of bicyclo [2,2,1] hepta-2-, which is a unit monomer, is substituted with Me, and the number of tertiary carbons is one higher than that of the resin material 5.

This “resin material 6” was dried at 70 ° C. for 6 hours to remove moisture, and then with an injection molding machine, the cylinder temperature was 280 ° C., the mold temperature was 80 ° C., the injection speed was 30 mm / sec, and the injection pressure was 80 MPa. The plate was formed.

Next, the plate was exposed to an atmosphere of 1.1 atm, normal temperature, and F ₂ gas concentration of 12% for 12 minutes to subject the plate to fluorination treatment. Samples of Here, the film thickness of the obtained fluorinated film was 100 nm.
(1.7) Example 3
100 parts by mass of 5,6-dimethyl-bicyclo [2,2,1] hept-2-ene and 7.6 parts by mass of 1-hexene are dissolved in 300 parts by mass of toluene, and 2 parts by mass of diethylaluminum chloride solution is dissolved therein. Then, 0.003 part by mass of tungsten hexachloride was added and stirred at 80 ° C. for 3 hours. After stirring, a large amount of methanol was put into the mixed solution to be solidified, and the solidified polymer was dried.

100 parts by mass of the obtained polymer was dissolved in tetrahydrofuran, 10 parts by mass of palladium / alumina was added thereto as a hydrogenation catalyst, and a hydrogenation reaction was carried out while heating and stirring at 170 ° C. under a pressure of 4 MPa for 4 hours. Thereafter, the catalyst was filtered to obtain “resin material 7”. In addition, the number of tertiary carbons per unit structure of the base resin in this “resin material 7” was 4, and the density of “resin material 7” was measured to be 1.01 g / cm ³ .

In the resin material 7, the 5- and 6-positions of bicyclo [2,2,1] hepta-2-, which is a unit monomer, are substituted, and the number of tertiary carbons is two more than that of the resin material 5, and four It is.

This “resin material 7” was dried at 70 ° C. for 6 hours to remove moisture, and then with an injection molding machine, the cylinder temperature was 280 ° C., the mold temperature was 80 ° C., the injection speed was 30 mm / sec, and the injection pressure was 80 MPa. The plate was formed.

Next, the plate is exposed to an atmosphere of 1.1 atm, normal temperature, and F ₂ gas concentration of 12% for 12 minutes to subject the plate to fluorination treatment. Samples of Here, the film thickness of the obtained fluorinated film was 100 nm.
(1.8) Example 4
Seven layers of TiO ₂ layers and SiO ₂ layers were alternately formed as antireflection films on the fluorinated film in the sample of Example 1, and the resulting plate was used as the sample of “Example 4”.
(2) Evaluation of sample (2.1) Evaluation of transmittance The reflectance and total light transmittance of each of the produced samples of Examples 1 to 3 and Comparative Examples 1 to 4 were measured, and the transmittance was measured according to the following criteria. Was evaluated, and the results were as shown in Table 1 above.

(Reflectance)
Using Olympus USPM-RUIII, the reflectance of the sample surface was directly measured to obtain the reflectance.

(Total light transmittance)
Using a U-4100 manufactured by Hitachi High-Tech Co., Ltd., the case where the sample was not attached to the entrance of the integrating sphere was taken as 100%, and measurement was conducted after the sample was attached.

○: Total light transmittance is 96% or more ×: Total light transmittance is less than 96% Further, when the light transmittance at 500 nm was measured for each sample of Examples 1 and 4, as shown in Table 2 above. became.

◎: Transmittance is 98% or more ○: Transmittance is less than 98% (3) Summary From the results shown in Table 1, the samples of Examples 1 to 3 have an antireflection effect compared to the samples of Comparative Examples 1 to 4. It can be seen that it has improved. From this, it was molded with a resin material having a resin having an alicyclic hydrocarbon structure, the number of tertiary carbons in the unit structure being 4 or more, and the density being 1.01 g / cm ³ or more. It can be seen that the antireflection effect is improved when the surface of the optical element (molded portion) is fluorinated.

Also, from the results in Table 2, it can be seen that the antireflection effect is further increased by adding an inorganic antireflection film on the fluorinated film.

DESCRIPTION OF SYMBOLS 30 Optical pick-up apparatus 32 Semiconductor laser oscillator 33 Collimator 34 Beam splitter 35 1/4 wavelength plate 36 Diaphragm 37 Objective lens 37a Front surface 37b Back surface 38 Sensor lens group 39 Sensor 40 Two-dimensional actuator 50 Molding part 55 Fluorinated film 60 Antireflection film 61 First layer 62 Second layer D Optical disc D ₁ Protective substrate D ₂ Information recording surface

Claims

An optical element having a molded part molded from a resin material,
The resin material is
A resin having an alicyclic hydrocarbon structure, wherein the number of tertiary carbons in the unit structure is 4 or more, and the density is 1.01 g / cm 3 or more;
The molded part is on the surface,
An optical element comprising a layer containing a resin in which at least a part of hydrogen constituting the alicyclic hydrocarbon structure is substituted with fluorine.
The optical element according to claim 1,
An optical element, wherein an antireflection coating made of an inorganic material is provided on the fluorinated film.
An optical pickup device comprising the optical element according to claim 1 as an objective lens.