JP2012027412A - Optical element and manufacturing method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical element allowing deterioration of a resin to be suppressed and light resistance to be enhanced.SOLUTION: An object lens for an optical pickup device using a light source having a wavelength range from 400 to 410 nm is disclosed as an exemplary optical element. The object lens comprises a resin molded part 50 made of a cycloolefin resin, on which a first film 62 is formed of a high density material having a mixing ratio of SiO:AlO=90 to 99:1 to 10 and a density of equal to or higher than 2.0 g/cm.

Description

  The present invention relates to an optical element and a method for manufacturing the same, and more particularly to an optical element having excellent light resistance and a method for manufacturing the same.

In resinous optical elements such as objective lenses used for blue light pickup applications, irradiation with blue laser (wavelength 405 nm) makes the resin easily clouded and deformed (deteriorated), in which case the spherical aberration fluctuates. , Writing to and reading from the disc becomes impossible. To cope with this, cycloolefin having high light resistance is used as a constituent material, and it is considered that the deterioration of the resin is caused by oxygen in the atmosphere or in the resin.
The technique of Patent Document 1 discloses an antireflection film composed of a plurality of layers. Specifically, the first layer and the second layer are made of SiO, and the film thickness is relatively thick at 400 nm or more. In order to improve the light resistance, an TiO ₂ film made of a high refractive index material is formed and densified by an ion plating method in the upper layer portion, and an oxygen barrier property is added (for example, paragraph) 0048-0053 etc.).

JP 2005-266780 A JP 2004-157497 A

Certainly, this method can improve the light resistance.
However, when the film thickness of the first and second SiO films made of the same material is increased to 400 nm, cracks are likely to occur, and when this occurs, oxygen in the atmosphere enters the resin and promotes deterioration of the resin. However, it takes time to form a film.
Furthermore, even if the TiO ₂ film made of a high refractive index material can be made dense by the ion plating method, it is difficult to secure a sufficient oxygen barrier property, and the resin is clouded and deformed by a blue laser and deteriorates. There is a possibility that the use of the ion plating method itself increases the equipment cost.
Accordingly, a main object of the present invention is to provide an optical element capable of suppressing deterioration of a resin and improving light resistance even when a blue laser is used, and a method for manufacturing the same.

In order to solve the above problems, according to one aspect of the present invention,
In an optical element for an optical pickup device using a light source having a wavelength of 400 to 410 nm,
Provided with a base material made of cycloolefin resin,
A first film made of a high-density material having a mixing ratio of SiO ₂ : Al ₂ O ₃ = 90 to 99: 1 to 10 and a density of 2.0 g / cm ³ or more is formed on the substrate. An optical element is provided.

According to another aspect of the invention,
In a method for manufacturing an optical element for manufacturing an optical element for an optical pickup device using a light source having a wavelength of 400 to 410 nm,
Forming a base material by molding a cycloolefin resin;
A high-density material having a mixing ratio of SiO ₂ : Al ₂ O ₃ = 90 to 99: 1 to 10 and a density of 2.0 g / cm ³ or more is deposited to form a first film on the substrate. And a process of
A method for manufacturing an optical element is provided.

  According to the present invention, since the first film made of a high-density material is formed on the resin base material, deterioration of the resin can be suppressed and light resistance can be improved even when a blue laser is used.

It is drawing which shows schematic structure of the optical pick-up apparatus used by preferable embodiment of this invention. It is a schematic sectional drawing which shows an example of the anti-reflective film used by preferable embodiment of this invention.

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

  As shown in FIG. 1, the optical pickup device 30 includes a semiconductor laser oscillator 32. The semiconductor laser oscillator 32 emits blue laser light (blue laser) having a specific wavelength (for example, 405 nm) having a wavelength of 400 to 410 nm for BD (Blu-ray Disc). The optical pickup device 30 is an example of an optical device, and the semiconductor laser oscillator 32 is an example of a light source.

  On the optical axis of the blue laser light emitted from the semiconductor laser oscillator 32, a collimator 33, a beam splitter 34, a quarter wavelength plate 35, a diaphragm 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 laser light described above.

  The objective lens 37 is disposed at a position facing the high-density optical disk D (BD optical disk), and condenses the blue laser light emitted from the semiconductor laser oscillator 32 on one surface of the optical disk D. Yes. The objective lens 37 is an example of an optical element, and the image-side numerical aperture NA is 0.7 or more. A flange portion is formed on the peripheral edge of the objective lens 37, and the flange portion is attached to the two-dimensional actuator 40. 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 resin molded portion 50, and an antireflection film 60 is formed on the surface 52 of the resin molded portion 50. The resin molding part 50 is an example of a base material.
In the present embodiment, the objective lens 37 includes a resin molded portion 50 and an antireflection film 60, and the antireflection film 60 is formed on the surface 37 a of the objective lens 37. In addition to the surface 37 a of the objective lens 37, the antireflection film 60 may be formed on the opposite surface (surface 37 b).

The resin molding part 50 is mainly composed of a resin made of a polymer having an alicyclic structure, preferably a cycloolefin resin, from the viewpoint of light resistance to blue laser light.
As the resin made of a polymer having an alicyclic structure, for example, the following resins 1 and 2 can be used. In order to improve the adhesion with the antireflection film 60, it is preferable to use the resin 1. .
Specific examples of the resin include ZEONEX manufactured by Nippon Zeon, APEL manufactured by Mitsui Chemicals, Arton manufactured by JSR, TOPAS manufactured by TOPAS ADVANCED POLYMERS Gmbh, and the like.

[Resin 1]
Resin material 1 has a repeating unit (a) having an alicyclic structure represented by the following formula (1) in a polymer all repeating unit having a weight average molecular weight (Mw) of 1,000 to 1,000,000. ) And a repeating unit (b) having a chain structure represented by the following formula (2) and / or the following formula (3) so that the total content is 90% by weight or more, and further the repeating unit The content of (b) is preferably 1% by weight or more and less than 10% by weight, and the chain of the repeating unit (a) preferably contains an alicyclic hydrocarbon copolymer that satisfies the following relational formula (Z).
A ≦ 0.3 × B (Z)
In relational formula (Z), A = (weight average molecular weight of a chain of repeating units having an alicyclic structure), and B = (weight average molecular weight (Mw) of alicyclic hydrocarbon copolymer) × (aliphatic The number of repeating units having a cyclic structure / the total number of repeating units constituting the alicyclic hydrocarbon-based copolymer).

  R1 to R13 in formula (1), formula (2), and formula (3) are each independently a hydrogen atom, chain hydrocarbon group, halogen atom, alkoxy group, hydroxy group, ether group, ester group, cyano group. Chain carbonization substituted with groups, amide groups, imide groups, silyl groups, and polar groups (halogen atoms, alkoxy groups, hydroxy groups, ether groups, ester groups, cyano groups, amide groups, imide groups, or silyl groups) Represents a hydrogen group or the like. Among these, a hydrogen atom or a chain hydrocarbon group having 1 to 6 carbon atoms is preferable because of excellent heat resistance and low water absorption. Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. Examples of the chain hydrocarbon group substituted with a polar group include halogenated alkyl groups having 1 to 20, preferably 1 to 10, more preferably 1 to 6 carbon atoms. As the chain hydrocarbon group, for example, an alkyl group having 1 to 20 carbon atoms, preferably 1 to 10 carbon atoms, more preferably 1 to 6 carbon atoms; 2 to 20 carbon atoms, preferably 2 to 10 carbon atoms, more preferably 2 to 2 carbon atoms. 6 alkenyl groups.

  X in Formula (1) represents an alicyclic hydrocarbon group, and the number of carbon atoms constituting the group is usually 4 to 20, preferably 4 to 10, and more preferably 5 to 7. . Birefringence can be reduced by setting the number of carbon atoms constituting the alicyclic structure within this range. The alicyclic structure is not limited to a monocyclic structure, and may be a polycyclic structure such as a norbornane ring or a dicyclohexane ring.

  The alicyclic hydrocarbon group may have a carbon-carbon unsaturated bond, but its content is 10% or less, preferably 5% or less, more preferably 3% or less of the total carbon-carbon bonds. is there. By setting the carbon-carbon unsaturated bond of the alicyclic hydrocarbon group within this range, transparency and heat resistance are improved. The carbon constituting the alicyclic hydrocarbon group includes a hydrogen atom, a hydrocarbon group, a halogen atom, an alkoxy group, a hydroxy group, an ether group, an ester group, a cyano group, an amide group, an imide group, a silyl group, and A chain hydrocarbon group or the like substituted with a polar group (halogen atom, alkoxy group, hydroxy group, ether group, ester group, cyano group, amide group, imide group, or silyl group) may be bonded. A hydrogen atom or a chain hydrocarbon group having 1 to 6 carbon atoms is preferred in terms of heat resistance and low water absorption.

  In addition, “...” In the formula (3) represents carbon-carbon saturation or carbon-carbon unsaturated bond in the main chain, but unsaturated bond is required when transparency and heat resistance are strongly required. The content of is usually 10% or less, preferably 5% or less, more preferably 3% or less, of all the carbon-carbon bonds constituting the main chain.

  Among the repeating units represented by the formula (1), the repeating unit represented by the following formula (4) is excellent in terms of heat resistance and low water absorption.

  Among the repeating units represented by the formula (2), the repeating unit represented by the following formula (5) is excellent in terms of heat resistance and low water absorption.

  Among the repeating units represented by the formula (3), the repeating unit represented by the following formula (6) is excellent in terms of heat resistance and low water absorption.

  In formula (4), formula (5) and formula (6), Ra, Rb, Rc, Rd, Re, Rf, Rg, Rh, Ri, Rj, Rk, Rl, Rm and Rn are each independently a hydrogen atom. Alternatively, it represents a lower chain hydrocarbon group, and a hydrogen atom or a lower alkyl group having 1 to 6 carbon atoms is excellent in terms of heat resistance and low water absorption.

  Among the repeating units having a chain structure represented by the formulas (2) and (3), the repeating unit having a chain structure represented by the formula (3) is stronger in the obtained hydrocarbon polymer. Excellent characteristics.

  In the present invention, a repeating unit (a) having an alicyclic structure represented by the formula (1) and a chain represented by the formula (2) and / or the formula (3) in the hydrocarbon copolymer. The total content with the repeating unit (b) of the shape structure is usually 90% or more, preferably 95% or more, more preferably 97% or more, on a weight basis. By setting the total content within the above range, low birefringence, heat resistance, low water absorption, and mechanical strength are highly balanced.

  The content of the repeating unit (b) having a chain structure in the alicyclic hydrocarbon copolymer is appropriately selected according to the purpose of use, but is usually 1% or more and less than 10%, preferably 1% on a weight basis. It is 8% or less, more preferably 2% or more and 6% or less. When the content of the repeating unit (b) is in the above range, low birefringence, heat resistance, and low water absorption are highly balanced.

  Further, the chain length of the repeating unit (a) is sufficiently shorter than the molecular chain length of the alicyclic hydrocarbon copolymer, specifically, A = (repeating unit chain having an alicyclic structure). Weight average molecular weight), B = (Weight average molecular weight of alicyclic hydrocarbon copolymer (Mw) × (number of repeating units having alicyclic structure / all repeats constituting alicyclic hydrocarbon copolymer) A) is 30% or less of B, preferably 20% or less, more preferably 15% or less, and particularly preferably 10% or less. When A is outside this range, the low birefringence is poor.

  About the manufacturing method of the said "polymer which has an alicyclic structure", it can manufacture by a conventionally well-known method.

  For example, the method for producing an alicyclic hydrocarbon-based copolymer includes: (1) copolymerizing an aromatic vinyl-based compound with another monomer that can be copolymerized, and carbon-carbon unsaturated bonds of the main chain and aromatic ring And (2) a method of copolymerizing an alicyclic vinyl compound with another monomer copolymerizable and hydrogenating as necessary.

[Resin 2]
Resin 2 is a resin comprising a copolymer of an α-olefin and a cyclic olefin represented by the following general formula (I) or (II).

…式（I）

... Formula (I)

In the formula (I), n is 0 or 1, m is 0 or a positive integer, k is 0 or 1, and R ^{1 to} R ¹⁸ and R ^a and R ^b are each independently a hydrogen atom. Represents a halogen atom or a hydrocarbon group.

…式（II）

... Formula (II)

In the formula (II), p and q are each independently 0 or a positive integer, r and s each independently represent 0, 1 or 2, and R ^{21 to} R ³⁹ are each independently a hydrogen atom. Represents a halogen atom, a hydrocarbon group or an alkoxy group.

[Cyclic olefins represented by general formulas (I) and (II)]
In the above general formula (I), 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.

  Moreover, as a hydrocarbon group, a C1-C20 alkyl group, a C1-C20 halogenated alkyl group, a C3-C15 cycloalkyl group, or an aromatic hydrocarbon group is mentioned normally. It is done. 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-exemplified monocyclic or polycyclic ring, the carbon atom numbered 1 or 2 is carbon bonded to R ¹⁵ (R ¹⁶ ) or R ¹⁷ (R ¹⁸ ) in the general formula (I), respectively. Represents an atom.

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

In general formula (II), 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). Moreover, as a hydrocarbon group, a C1-C20 alkyl group, a C3-C15 cycloalkyl group, or an aromatic hydrocarbon group is mentioned normally. 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 R ³¹ jointly form a methylene group (—CH ₂ -), Ethylene group (—CH ₂ CH ₂ —) or propylene group (—CH ₂ CH ₂ CH ₂ —) of any alkylene group is formed.

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 synonymous with q in the general formula (II).

  Specific examples of the cyclic olefin represented by the general formula (I) or (II) according to the present invention include bicyclo-2-heptene derivatives (bicyclohept-2-ene derivatives), tricyclo-3-decene derivatives, tricyclo -3-undecene derivatives, tetracyclo-3-dodecene derivatives, pentacyclo-4-pentadecene derivatives, pentacyclopentadecadiene derivatives, pentacyclo-3-pentadecene derivatives, pentacyclo-3-hexadecene derivatives, pentacyclo-4-hexadecene derivatives, hexacyclo- 4-heptadecene derivative, heptacyclo-5-eicosene derivative, heptacyclo-4-eicosene derivative, heptacyclo-5-heneicosene derivative, octacyclo-5-docosene derivative, nonacyclo-5-pentacocene derivative, 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.

  Specific examples of the cyclic olefin represented by the general formula (I) or (II) according to the present invention are shown below, but the present invention is not limited to these exemplified compounds.

<< Bicyclo [2.2.1] hept-2-ene derivative >>
1) Bicyclo [2.2.1] hept-2-ene 2) 6-Methylbicyclo [2.2.1] hept-2-ene 3) 5,6-Dimethylbicyclo [2.2.1] hept- 2-ene 4) 1-methylbicyclo [2.2.1] hept-2-ene 5) 6-ethylbicyclo [2.2.1] hept-2-ene 6) 6-n-butylbicyclo [2. 2.1] Hept-2-ene 7) 6-Isobutylbicyclo [2.2.1] hept-2-ene 8) 7-Methylbicyclo [2.2.1] hept-2-ene, etc.

<< Tetracyclo [4.4.0.1 ^2,5 . ^1,7,10 ] -3-dodecene derivative >>
9) Tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene 10) 8-Methyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene 11) 8-ethyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene 12) 8-propyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene 13) 8-Butyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene 14) 8-isobutyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene 15) 8-hexyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene 16) 8-cyclohexyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene 17) 8-stearyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene 18) 5,10-dimethyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene 19) 2,10-dimethyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene 20) 8,9-dimethyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene 21) 8-ethyl-9-methyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene 22) 11,12-dimethyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene 23) 2,7,9-trimethyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene 24) 9-ethyl-2,7-dimethyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene 25) 9-isobutyl-2,7-dimethyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene 26) 9,11,12-trimethyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene 27) 9-ethyl-11,12-dimethyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene 28) 9-isobutyl-11,12-dimethyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene 29) 5,8,9,10-tetramethyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene 30) 8-ethylidenetetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene 31) 8-ethylidene-9-methyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene 32) 8-ethylidene-9-ethyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene 33) 8-ethylidene-9-isopropyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene 34) 8-ethylidene-9-butyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene 35) 8-n-propylidenetetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene 36) 8-n-propylidene-9-methyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene 37) 8-n-propylidene-9-ethyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene 38) 8-n-propylidene-9-isopropyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene 39) 8-n-propylidene-9-butyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene 40) 8-isopropylidenetetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene 41) 8-isopropylidene-9-methyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene 42) 8-isopropylidene-9-ethyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene 43) 8-isopropylidene-9-isopropyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene 44) 8-isopropylidene-9-butyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene 45) 8-chlorotetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene 46) 8-Bromotetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene 47) 8-fluorotetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene 48) 8,9-dichlorotetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene, etc.

<< Hexacyclo [6.6.1.1 ^3,6 . 1 ^10,13 . 0 ^2,7 . 0 ^9,14] -4-heptadecene derivative "
49) Hexacyclo [6.6.1.1 ^3,6 . 1 ^10,13 . 0 ^2,7 . 0 ^9,14] -4-heptadecene 50) 12-methyl hexa cyclo [6.6.1.1 ^{3, 6.} 1 ^10,13 . 0 ^2,7 . 0 ^9,14 ] −
4-Heptadecene 51) 12-ethylhexacyclo [6.6.1.1 ^3,6 . 1 ^10,13 . 0 ^2,7 . 0 ^9,14 ] −
4-heptadecene 52) 12-isobutylhexacyclo [6.6.1.1 ^3,6 . 1 ^10,13 . 0 ^2,7 . 0 ^9,14
] -4-heptadecene 53) 1,6,10-trimethyl-12-isobutylhexacyclo [6.6.1.1 ^3,6 . 1 ^10,13 . 0 ^2,7 . 0 ^9,14] -4-heptadecene, etc.

<< Octacyclo [8.8.0.1 ^2,9 . 1 ^4,7 . 1 ^11,18 . 1 ^13,16 . 0 ^3,8 . 0 ^12,17 ] -5-docosene derivative >>
54) Octacyclo [8.8.0.1 ^2,9 . 1 ^4,7 . 1 ^11,18 . 1 ^13,16 . 0 ^3,8 . 0 ^12,17 ] -5-docosene 55) 15-methyloctacyclo [8.8.0.1 ^2,9 . 1 ^4,7 . 1 ^11,18 . 1 ^13,16 . 0 ^3,8 . 0 ^12,17 ] -5-docosene 56) 15-ethyloctacyclo [8.8.0.1 ^2,9 . 1 ^4,7 . 1 ^11,18 . 1 ^13,16 . 0 ^3,8 . 0 ^12,17 ] -5-docosene, etc.

<< Pentacyclo [6.6.1.1 ^3,6 . 0 ^2,7 . 0 ^9,14 ] -4-hexadecene derivative >>
57) Pentacyclo [6.6.1.1 ^3,6 . 0 ^2,7 . 0 ^9,14 ] -4-hexadecene 58) 1,3-dimethylpentacyclo [6.6.1.1 ^3,6 . 0 ^2,7 . 0 ^9,14 ] -4-hexadecene 59) 1,6-dimethylpentacyclo [6.6.1.1 ^3,6 . 0 ^2,7 . 0 ^9,14 ] -4-hexadecene 60) 15,16-dimethylpentacyclo [6.6.1.1 ^3,6 . 0 ^2,7 . 0 ^9,14 ] -4-hexadecene, etc.

<Heptacyclo-5-eicosene derivative or heptacyclo-5-heneicosene derivative>
61) Heptacyclo [8.7.0.1 ^2,9 . 1 ^4,7 . 1 ^11,17 . 0 ^3,8 . 0 ^12,16 ] -5
Eicosene 62) Heptacyclo [8.8.0.1 ^2,9 . 1 ^4,7 . 1 ^11,18 . 0 ^3,8 . 0 ^12,17 ] -5
Henikosen, etc.

<< Tricyclo [4.3.0.1 ^2,5 ] -3-decene derivative >>
63) Tricyclo [4.3.0.1 ^2,5 ] -3-decene 64) 2-Methyltricyclo [4.3.0.1 ^2,5 ] -3-decene 65) 5-Methyltricyclo [ 4.3.0.1 ^2,5 ] -3-decene, etc.

<< Tricyclo [4.4.0.1 ^2,5 ] -3-undecene derivative >>
66) Tricyclo [4.4.0.1 ^2,5 ] -3-undecene 67) 10-Methyltricyclo [4.4.0.1 ^2,5 ] -3-undecene, etc.

<< Pentacyclo [6.5.1.1 ^3,6 . 0 ^2,7 . 0 ^9,13 ] -4-pentadecene derivative >>
68) Pentacyclo [6.5.1.1 ^3,6 . 0 ^2,7 . 0 ^9,13 ] -4-pentadecene 69) 1,3-dimethylpentacyclo [6.5.1.1 ^3,6 . 0 ^2,7 . 0 ^9,13 ] -4-pentadecene 70) 1,6-dimethylpentacyclo [6.5.1.1 ^3,6 . 0 ^2,7 . 0 ^9,13 ] -4-pentadecene 71) 14,15-dimethylpentacyclo [6.5.1.1 ^3,6 . 0 ^2,7 . 0 ^9,13 ] -4-pentadecene, etc.

<Diene compound>
72) Pentacyclo [6.5.1.1 ^3,6 . 0 ^2,7 . 0 9,13] -4, ^10- pentadecadien, etc.

<< Pentacyclo [7.4.0.1 ^2,6 . 1 ^9,12 . 0 ^8,13 ] -3-pentadecene derivative >>
73) Pentacyclo [7.4.0.1 ^2,6 . 1 ^9,12 . 0 ^8,13] -3-pentadecene 74) methyl-substituted pentacyclo [7.4.0.1 ^2,6. 1 ^9,12 . 0 ^8,13 ] -3-pentadecene, etc.

<< Heptacyclo [8.7.0.1 ^3,6 . 1 ^10,17 . 1 ^12,15 . 0 ^2,7 . 0 ^11,16 ] -4-eicosene derivative >>
75) Heptacyclo [8.7.0.1 ^3,6 . 1 ^10,17 . 1 ^12,15 . 0 ^2,7 . 0 ^11,16 ] -4
-Eicosene 76) Dimethyl-substituted heptacyclo [8.7.0.1 ^3,6 . 1 ^10,17 . 1 ^12,15 . 0 ^2,7 . 0 ^11,16 ] -4-Eicosen, etc.

<< Nonacyclo [10.9.1.1 ^4,7 . 1 ^13,20 . 1 ^15,18 . 0 ^3,8 . 0 ^2,10 . 0 ^12,21 .
0 ^{14, 19]} -5-pentacosenoic derivative "
77) Nonacyclo [10.9.1.1 ^4,7 . 1 ^13,20 . 1 ^15,18 . 0 ^3,8 . 0 ^2,10 . 0 ^12,21 . 0 ^14,19] -5-pentacosene 78) trimethyl-substituted Nonashikuro [10.9.1.1 ^{4, 7.} 1 ^13,20 . 1 ^15,18 . 0 ^3,8 . 0 ^2,10 . 0 ^12,21 . 0 ^{14, 19]} -5-pentacosenoic, etc.

<< Pentacyclo [8.4.0.1 ^2,5 . 1 ^9,12 . 0 ^8,13 ] -3-hexadecene derivative >>
79) Pentacyclo [8.4.0.1 ^2,5 . 1 ^9,12 . 0 ^8,13 ] -3-hexadecene 80) 11-methyl-pentacyclo [8.4.0.1 ^2,5 . 1 ^9,12 . 0 ^8,13 ] -3-hexadecene 81) 11-ethyl-pentacyclo [8.4.0.1 ^2,5 . 1 ^9,12 . 0 ^8,13 ] -3-hexadecene 82) 10,11-dimethyl-pentacyclo [8.4.0.1 ^2,5 . 1 ^9,12 . 0 ^8,13 ]
-3-hexadecene, etc.

<< Heptacyclo [8.8.0.1 ^4,7 . 1 ^11,18 . 1 ^13,16 . 0 ^3,8 . 0 ^12,17 ] -5- ^Heneicosene derivative >>
83) Heptacyclo [8.8.0.1 ^4,7 . 1 ^11,18 . 1 ^13,16 . 0 ^3,8 . 0 ^12,17 ] -5
Haneicosene 84) 15-Methyl-heptacyclo [8.8.0.1 ^4,7 . 1 ^11,18 . 1 ^13,16 . 0 ^3,8 . 0 ^12,17 ] -5- ^Heneicosene 85) Trimethyl-heptacyclo [8.8.0.1 ^4,7 . 1 ^11,18 . 1 ^13,16 . 0 ^3,8 . 0 ^12,17 ] -5- ^Haneikosen , etc.

<< Nonacyclo [10.10.1 ^5,8 . 1 ^14,21 . 1 ^16,19 . 0 ^2,11 . 0 ^4,9 . 0 ^13,22
. 0 ^15,20] -5-hexacosenoic derivative "
86) Nonacyclo [10.10.1 ^5,8 . 1 ^14,21 . 1 ^16,19 . 0 ^2,11 . 0 ^4,9 . 0 ^13,22 . 0 ^15,20] -5-hexacosenoic, etc.

<Others>
87) 5-Phenyl-bicyclo [2.2.1] hept-2-ene 88) 5-Methyl-5-phenyl-bicyclo [2.2.1] hept-2-ene 89) 5-Benzyl-bicyclo [ 2.2.1] hept-2-ene 90) 5-tolyl-bicyclo [2.2.1] hept-2-ene 91) 5- (ethylphenyl) -bicyclo [2.2.1] hept-2 -Ene 92) 5- (isopropylphenyl) -bicyclo [2.2.1] hept-2-ene 93) 5- (biphenyl) -bicyclo [2.2.1] hept-2-ene 94) 5- ( β-naphthyl) -bicyclo [2.2.1] hept-2-ene 95) 5- (α-naphthyl) -bicyclo [2.2.1] hept-2-ene 96) 5- (anthracenyl) -bicyclo [2.2.1] Hept-2-ene 97) 5,6 Diphenyl-bicyclo [2.2.1] hept-2-ene 98) Cyclopentadiene-acenaphthylene adduct 99) 1,4-methano-1,4,4a, 9a-tetrahydrofluorene 100) 1,4-methano-1 4,4a, 5,10,10a-hexahydroanthracene 101) 8-phenyl-tetracyclo [4.4.0.0 ^3,5 . 1 ^7,10 ] -3-dodecene 102) 8-methyl-8-phenyl-tetracyclo [4.4.0.0 ^3,5 . 1 ^7,10 ] -3-dodecene 103) 8-benzyl-tetracyclo [4.4.0.0 ^3,5 . 1 ^7,10 ] -3-dodecene 104) 8-Tolyl-tetracyclo [4.4.0.0 ^3,5 . 1 ^7,10 ] -3-dodecene 105) 8- (ethylphenyl) -tetracyclo [4.4.0.0 ^3,5 . 1 ^7,10 ] -3-dodecene 106) 8- (Isopropylphenyl) -tetracyclo [4.4.0.0 ^3,5 . 1 ^7,10 ] -3-dodecene 107) 8,9-diphenyl-tetracyclo [4.4.0.0 ^3,5 . 1 ^7,10 ] -3-dodecene 108) 8- (biphenyl) -tetracyclo [4.4.0.0 ^3,5 . 1 ^7,10 ] -3-dodecene 109) 8- (β-naphthyl) -tetracyclo [4.4.0.0 ^3,5 . 1 ^7,10 ] -3-dodecene 110) 8- (α-naphthyl) -tetracyclo [4.4.0.0 ^3,5 . 1 ^7,10 ] -3-dodecene 111) 8- (anthracenyl) -tetracyclo [4.4.0.0 ^3,5 . 1 ^7,10 ] -3-dodecene 112) (cyclopentadiene-acenaphthylene adduct) and cyclopentadiene further added 113) 11,12-benzo-pentacyclo [6.5.1.1 ^3,6 . 0 ^2,7 . 0 ^9,13 ] -4-pentadecene 114) 11,12-benzo-pentacyclo [6.5.1.1 ^3,6 . 0 ^2,7 . 0 ^9,13] -4-hexadecene 115) 11-phenyl - hexacyclo [6.6.1.1 ^{3, 6.} 1 ^10,13 . 0 ^2,7 . 0 ^9,14] -4-heptadecene 116) 14,15-benzo - heptacyclo [8.7.0.1 ^2,9. 1 ^4,7 . 1 ^11,17 .
0 ^3,8 . 0 ^12,16 ] -5-Eicosen

[Α-olefin]
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, Examples include linear α-olefins such as 1-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 singly 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, Alkoxycarbonyl, carboxyl, cyano, nitro, halogen-substituted alkoxy, halogen-substituted aryloxy, pyrrolyl, and the like each group and a halogen atom tetrazolyl, and the like.

  As said alkyl group, a C1-C32 thing is preferable and may be linear or branched. As the aryl group, a phenyl group is preferable.

  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 an arylureido group; the sulfamoylamino group is preferably an alkylsulfamoylamino group or an arylsulfamoylamino group; 2-furyl, 2-thienyl, 2-pyrimidinyl, 2-benzothiazolyl, etc .; the saturated heterocyclic ring is preferably a 5- to 7-membered one, specifically tetrahydropyranyl, tetrahydrothiopyranyl, etc .; heterocyclic oxy The group preferably has a 5- to 7-membered heterocyclic ring, such as 3,4,5,6-tetrahydropyranyl-2-oxy, 1-phenyltetrazol-5-oxy, etc .; 5- to 7-membered heterocyclic thio groups are preferred, for example 2-pyridylthio, 2-benzothiazolylthio, 2,4-diphenoxy-1 3,5-triazole-6-thio, etc .; as siloxy group, trimethylsiloxy, triethylsiloxy, dimethylbutylsiloxy, etc .; as imide group, succinimide, 3-heptadecyl succinimide, phthalimide, glutarimide, etc .; remaining spiro compound As the group, spiro [3.3] heptan-1-yl and the like; as the bridged hydrocarbon compound residue, bicyclo [2.2.1] heptan-1-yl, tricyclo [3.3.1.13.7 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-N group. An arylcarbamoyl group and the like; an acyl group such as an alkylcarbonyl group and an arylcarbonyl group; an acyloxy group such as an alkylcarbonyloxy group and the like; an oxycarbonyl group such as an alkoxycarbonyl group and an aryloxycarbonyl group; a halogen-substituted alkoxy group Α-halogen-substituted alkoxy group and the like; halogen-substituted aryloxy groups such as tetrafluoroaryloxy group and pentafluoroaryloxy group; pyrrolyl group such as 1-pyrrolyl and the like; tetrazolyl group such as 1-tetrazolyl and the like Groups.

  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.

  Further, the acyclic monomer content in the copolymer is preferably 20% by mass 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.

The antireflection film 60 is an example of a functional film, and has a multilayer structure in which a plurality of layers are stacked.
Specifically, as shown in FIG. 2, the first film 62 of the first layer is directly formed on the surface 52 of the resin molded portion 50, and the second film 64 of the second layer is formed on the first film 62. The third film 66 of the third layer is formed on the second film 64.

The first film 62 is made of a high-density material having a mixing ratio of SiO ₂ : Al ₂ O ₃ = 90 to 99: 1 to 10 and a density of 2.0 g / cm ³ or more. As the high density material, HDL5 manufactured by Merck Co., Ltd. is preferably used. “Density” as used herein is a value measured by filling a granular (about 1 to 2 mm in diameter) high-density material into a 1 l (liter) container. As a high-density material, HDL5 manufactured by Merck Ltd. Is the value measured according to the measurement method of Merck Co., Ltd.
The first film 62 is composed of SiO ₂ and Al ₂ O _3, and the total mixing ratio of these two compounds is preferably 100.
The first film 62 has a refractive index with respect to light having a wavelength of 400 to 410 nm of 1.47 to 1.52, and a film thickness of 15 to 300 nm.

The second film 64 is made of a high refractive index material having a refractive index of 1.61 or more with respect to light having a wavelength of 400 to 410 nm, preferably ZrO ₂ , TiO ₂ , a mixture of ZrO ₂ and TiO ₂ , Ta It is composed of any of ₂ O ₅ , a mixture of Ta ₂ O ₅ and TiO ₂ . The second film 64 may be composed of Sc ₂ O ₃ , LaO ₃ , LaF ₂ , Y ₂ O ₃ , HfO ₂ , TaO, TiO ₂ , Nb ₂ O ₃ SiN, or a mixture thereof.
The second film 64 has a thickness of 15 to 1000 nm.

The third film 66 is the same film as the first film 62.
In the present embodiment, the antireflection film 60 may be composed of only the first film 62 or may be composed of the first film 62 and the second film 64. In the case of only the first film 62, the antireflection performance may be reduced as compared with the case where the films of the low refractive index material and the high refractive index material are alternately laminated.
Of course, the antireflection film 60 may have a layer structure of four or more layers by alternately stacking the first film 62 and the second film 64 on the third film 66.

The first film 62 and the third film 66 may be composed of films made of different materials.
For example, the first film is made of a high-density material having a mixing ratio of SiO ₂ : Al ₂ O ₃ = 90 to 99: 1 to 10 and a density of 2.0 g / cm ³ or more. May be made of a low refractive index material such as SiO ₂ .
Conversely, the first film is made of a low refractive index material such as SiO ₂ , and the third film has a mixing ratio of SiO ₂ : Al ₂ O ₃ = 90 to 99: 1 to 10 and a density of 2 It may be composed of a high density material of 0.0 g / cm ³ or more. In addition, the surface of the resin molding part 50 is made of a film made of a high-density material having a mixing ratio of SiO ₂ : Al ₂ O ₃ = 90 to 99: 1 to 10 and a density of 2.0 g / cm ³ or more. The film may be formed directly on the surface 52, or a film made of a different material may be formed between the film made of the high-density material and the surface 52.

  Then, an example of the manufacturing method of the objective lens 37 is demonstrated.

First, the resin is injection molded into a mold under a certain condition to form a resin molded portion 50 having a predetermined shape.
Thereafter, using the high-density material as a deposition source, a vacuum deposition process is performed on the surface 52 of the resin molded portion 50 to form the first film 62.
Thereafter, a second film 64 is formed on the first film 62 and a third film 66 is formed on the second film 64 by vacuum deposition. In the case of forming the antireflection film 60 having a layer structure of four or more layers, the step of forming the first film 62 (or the third film 66) and the step of forming the second film 64 are repeated. Just do it.
Through the above processing, the antireflection film 60 can be formed on the surface 52 of the resin molded part 50, whereby the objective lens 37 can be manufactured.

  Next, the operation of the optical pickup device 30 will be described.

Blue laser 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 laser light passes through the collimator 33 and is collimated into infinite parallel light, then passes through the beam splitter 34 and passes through the quarter wavelength plate 35. Furthermore, after passing through the blue laser beam 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.

Blue laser 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 present embodiment described above, the first lens 62 and the third film 66 made of a high-density material are formed on the objective lens 37 as a part of the antireflection film 60. The first film 62 and the third film 66 are made of a special material having a constant composition and high density, and are excellent in light resistance (see the following examples).
In addition, since the first film 62 and the third film 66 are not so thick as 15 to 300 nm, cracks hardly occur even if the film is continuously irradiated with blue laser light, and the film thickness is 300 nm. The film formation time can be shortened as compared with the case of forming a film exceeding the thickness.
Further, since the first film 62 and the third film 66 made of a special material are formed on the objective lens 37, the second film 64 made of a high refractive index material is formed by an ion plating method. Since there is no need for densification, the equipment cost does not increase.

In Example 1, usable high-density materials (mixing ratio of Al ₂ O ₃ ) were examined.
First, cycloolefin resin (APEL-NH) resin was injection molded to form a resin molded portion (resin lens). The resin lens was an objective lens of an optical pickup device dedicated to blue laser light having an effective diameter of 1 mm and an axial thickness of 1.57 mm.
High-density materials (HDL5 manufactured by Merck & Co., Inc.) having a mixing ratio of Al ₂ O ₃ of 1%, 2%, 5%, 8%, 10%, and 12% are vacuum-deposited on the resin molded part. When the film was formed by this method, the film could be formed when the mixing ratio was 1 to 10%, but the film could not be formed when the mixing ratio was 12%.
From this, it was found that the high-density material can be used when the mixing ratio of Al ₂ O ₃ is in the range of 1 to 10%.

In Example 2, a film material having excellent light resistance was examined.
(1) Preparation of sample The resin molding part similar to Example 1 was formed. Thereafter, a standard material (L5 manufactured by Merck & Co., Inc.) and a high-density material (Merck (Merck Corp.)) of SiO ₂ material, SiO material, SiO ₂ : Al ₂ O ₃ = 90 to 99: 1 to 10 for the resin molded part. A single layer film made of each material of HDL5) manufactured by Co., Ltd. was formed by vacuum deposition, and these were designated as “Samples 1 to 4” (see Table 1). Table 1 also shows the physical properties (density, refractive index with respect to light having a wavelength of 405 nm, film thickness) of each material.
In particular, L5 of sample 1 and HDL5 of sample 4 have the same chemical composition but different specific gravity. In samples 1, 2, and 4, the film thickness is set to 100 nm, which is 1/4 of the wavelength of the light resistance test (see next item), and in sample 3, the film thickness is set to 400 nm, which is substantially the same as the light resistance test wavelength.

(2) Sample evaluation (2.1) Heat resistance test and results Each sample was allowed to stand in a temperature environment of 85 ° C. for 1 week, and whether or not cracks (film cracks) had occurred after 1 week had passed. Observed at. The observation results are shown in Table 1.
In Table 1, the criteria for ○ and × are as follows.
“○”: No cracks are observed “×”: Cracks are observed (2.2) Light resistance test and results Under a temperature environment of 85 ° C., a blue laser with a wavelength of 405 nm is applied to each sample. Irradiation was continued for 1 week at 150 mW, and spherical aberration before and after irradiation was measured with a surface interferometer to calculate the variation, and the light resistance of the film was evaluated from the calculation result. The evaluation results are shown in Table 1.
In Table 1, the criteria for ◎, ○, △, × are as follows.
“◎”: The fluctuation amount is less than ± 10 mλ “O”: The fluctuation amount is ± 10 mλ or more and less than ± 20 mλ “△”: The fluctuation amount is ± 20 mλ or more and less than ± 50 mλ “×”: The fluctuation amount Is ± 50 mλ or more

(3) Summary As shown in Table 1, in the heat resistance test, the resin molded part expanded, but Samples 2 and 3 could not follow the expansion, and cracks were generated. In the light resistance test, the result of Sample 4 was superior to that of Samples 1 to 3, and the light resistance was improved.
From these results, it can be seen that forming a film of a high density material having a constant composition can improve light resistance without depending on heat resistance.

In Example 3, the optimum film thickness of a film made of a high-density material was examined.
A resin molded part similar to that in Example 1 was formed. Thereafter, a single layer film made of each material of high density material (HDL5 manufactured by Merck Co., Ltd.) is formed on the resin molded part by a vacuum deposition method while changing the film thickness from 10 nm to a value exceeding 300 nm. These were designated as “Samples 11 to 18” (see Table 2).
Thereafter, the same light resistance test as in Example 2 was performed, and the optimum film thickness was examined by the same evaluation as in Example 2.

As shown in Table 2, although the light resistance is good in samples 12 to 17, the light resistance is lowered in sample 11 having a film thickness of 10 nm, and cracks are observed during the light resistance test in sample 18 having a film thickness exceeding 300 nm. The spherical aberration was not measured.
From these results, it was found that the film thickness of 15 to 300 nm is optimal for improving light resistance.

In Example 4, an optimum film configuration including a film made of a high-density material was examined.
(1) Preparation of sample The resin molding part similar to Example 1 was formed. Thereafter, a single-layer or multi-layer film shown in Table 3 was formed and laminated on the resin molded portion by vacuum vapor deposition treatment, and “samples 21 to 27” were formed according to the film configuration.
In Table 3, the lowest layer in the “film configuration” item is the first first film, which is a film formed directly on the resin molded portion.
In Table 3, the resin-molded portion of sample 22 was subjected to oxidation treatment. As an oxidation treatment, it was stored for 48 hours in an environment of 60 ° C. and 80% RH. The first film (SiO) of sample 2 was formed by vacuum vapor deposition using a resistance heating method.
In Table 3, “OA600” of Sample 22 is a film prepared by evaporating the deposition source using OA600 manufactured by Optran as the deposition source, and is a (Ta ₂ O ₅ + 5% TiO ₂ ) film. When forming the film of OA600, the film was formed while discharging with a high-frequency power source, and the film was densified.

(2) Sample Evaluation (2.1) Light Resistance Test and Results The light resistance test similar to that of Example 2 was performed, and the optimum film configuration was examined by the same evaluation as in Example 2.
(2.2) Evaluation of antireflection performance Using Hitachi spectrophotometer U-4100, the transmittance | permeability (%) of each sample 21-27 with respect to the light of wavelength 405nm was measured. Table 3 shows the measurement results.
In Table 3, the criteria for ◎ and ○ are as follows.
“◎”: The transmittance is 93% or more “◯”: The transmittance is less than 93% and 91% or more

(3) Summary As shown in Table 3, Samples 23 to 27 including a film made of a high-density material were superior in light resistance to Samples 21 and 22 not including this. However, since the sample 23 is a single-layer film made of a high-density material, the antireflection performance is lower than that of the samples 24-27 having a multilayer structure.
From these results, it was found that including a film of a high density material having a constant composition and keeping the thickness of each layer within a certain range is useful for improving light resistance.

DESCRIPTION OF SYMBOLS 30 Optical pick-up apparatus 32 Semiconductor laser oscillator 33 Collimator 34 Beam splitter 35 1/4 wavelength plate 36 Aperture 37 Objective lens 37a, 37b Surface 38 Sensor lens group 39 Sensor 40 Two-dimensional actuator 50 Resin molding part 52 Surface 60 Antireflection film 62 1st 1 film 64 second film 66 third film D optical disk D ₁ protective substrate D ₂ information recording surface

Claims (8)

In an optical element for an optical pickup device using a light source having a wavelength of 400 to 410 nm,
Provided with a base material made of cycloolefin resin,
A first film made of a high-density material having a mixing ratio of SiO ₂ : Al ₂ O ₃ = 90 to 99: 1 to 10 and a density of 2.0 g / cm ³ or more is formed on the substrate. An optical element. The optical element according to claim 1,
An optical element, wherein the first film has a refractive index of 1.47 to 1.52 at a wavelength of 400 to 410 nm, and the thickness of the first film is 15 to 300 nm. The optical element according to claim 1 or 2,
An optical element, wherein a second film having a refractive index of 1.61 or more and a film thickness of 15 to 1000 nm at a wavelength of 400 to 410 nm is formed on the first film. The optical element according to claim 3.
The optical element, wherein the first film and the second film are alternately laminated on the base material. In a method for manufacturing an optical element for manufacturing an optical element for an optical pickup device using a light source having a wavelength of 400 to 410 nm,
Forming a base material by molding a cycloolefin resin;
A high-density material having a mixing ratio of SiO ₂ : Al ₂ O ₃ = 90 to 99: 1 to 10 and a density of 2.0 g / cm ³ or more is deposited to form a first film on the substrate. And a process of
An optical element manufacturing method comprising: In the manufacturing method of the optical element according to claim 5,
The method of manufacturing an optical element, wherein the first film has a refractive index of 1.47 to 1.52 at a wavelength of 400 to 410 nm, and the film thickness of the first film is 15 to 300 nm. In the manufacturing method of the optical element according to claim 5 or 6,
A method for manufacturing an optical element, comprising: forming a second film having a refractive index of 1.61 or more and a thickness of 15 to 1000 nm on a wavelength of 400 to 410 nm on the first film. In the manufacturing method of the optical element according to claim 7,
The step of forming the first film is executed again, or the step of forming the first film and the step of forming the second film are repeatedly executed, and the first film and the second film are formed. A process for producing an optical element comprising the step of alternately laminating the film.

Images