JP2008234702A - Optical pickup device and objective lens - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical pickup device for sharing an optical system even while presenting stable performance for a long period for information recording and/or playbacking to and from different optical information recording media, and to provide an objective lens to be used for the optical pickup device. <P>SOLUTION: Since a second objective lens part OBJ2 is made of resin material having an ultraviolet resistance effect, even when luminous flux of wavelength λ1 is reflected from a first raised mirror M1, deterioration due to the reflection of the luminous flux is suppressed, and stable optical performance can be presented for a long period. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an optical pickup apparatus and an objective lens capable of recording and / or reproducing information with respect to different types of optical information recording media (also referred to as optical disks).

  In recent years, research and development of high-density optical disc systems that can record and / or reproduce information (hereinafter, “recording and / or reproduction” is referred to as “recording / reproduction”) using a blue-violet semiconductor laser having a wavelength of about 400 nm. Development is progressing rapidly. As an example, in an optical disc for recording / reproducing information with specifications of NA 0.85 and light source wavelength 405 nm, so-called Blu-ray Disc (hereinafter referred to as BD), DVD (NA 0.6, light source wavelength 650 nm, storage capacity 4, 7 GB) Can record information of 23 to 27 GB per layer on an optical disk with a diameter of 12 cm, which is the same size as the above, and an optical disk that records and reproduces information with specifications of NA 0.65 and light source wavelength 405 nm, so-called With HD DVD (hereinafter referred to as HD), information of 15 to 20 GB per layer can be recorded on an optical disk having a diameter of 12 cm. In the BD, since coma aberration generated due to the tilt (skew) of the optical disk increases, the protective layer is designed to be thinner than in the DVD (0.1 mm with respect to 0.6 mm of the DVD) The amount of coma due to skew is reduced. Hereinafter, in this specification, such an optical disc is referred to as a “high-density optical disc”.

  Also, given the reality that DVDs and CDs (compact discs) on which a wide variety of information is recorded are currently being sold, information can be appropriately recorded on as many different types of optical discs as possible with a single player. It is desired to enable reproduction. Furthermore, considering that the optical pickup device is mounted on a notebook personal computer or the like, it is not only necessary to have compatibility with a plurality of types of optical discs, but it is important to further promote downsizing.

Here, Patent Document 1 discloses an optical pickup device capable of recording and / or reproducing information in a manner compatible with a high-density optical disc and a DVD / CD using a plurality of optical elements.
JP 2004-319062 A

  However, in order to further reduce the cost and size of the optical pickup device, it is important to share the optical path from the light source to the optical disk. Here, the blue-violet laser beam for high-density optical discs and the red laser beam for DVDs or infrared laser beam for CDs have different wavelengths. Reflective selection elements have also been developed. By arranging such a selection element in the common optical path, for example, the blue-violet laser beam can be transmitted and the red or infrared laser beam can be reflected. Blue-violet laser light can be incident on the objective lens for the density optical disk, and red or infrared laser light can be incident on the objective lens for DVD / CD.

  However, it has been confirmed that in an optical pickup device in which a blue-violet laser beam and a red or infrared laser beam are branched using a selection element, a problem occurs in DVD / CD recording / reproduction due to long-term use. . Such a problem does not occur when the same objective lens for DVD / CD is used in an optical pickup device that supports only DVD / CD.

  The present invention has been made in view of the problems of the prior art, and in order to perform information recording and / or reproduction with respect to different optical information recording media including optical information recording media using blue-violet laser light, An object of the present invention is to provide an optical pickup device and an objective lens capable of sharing an optical system while exhibiting stable performance for a long period of time.

  In this specification, an optical disk (also referred to as an optical information recording medium) that uses a blue-violet semiconductor laser or a blue-violet SHG laser as a light source for recording / reproducing information is generally referred to as a “high-density optical disk”, and NA0 In addition to a standard optical disc (for example, BD: Blu-ray Disc) in which information is recorded / reproduced by an objective optical system of .85 and the thickness of the protective layer is about 0.1 mm, NA 0.65 to 0.67 Information is recorded / reproduced by the objective optical system, and includes a standard optical disc (for example, HD DVD: also simply referred to as HD) having a protective layer thickness of about 0.6 mm. In addition to an optical disc having such a protective layer on its information recording surface, an optical disc having a protective film with a thickness of several to several tens of nanometers on the information recording surface, the thickness of the protective layer or protective film It also includes an optical disc with 0. In this specification, the high-density optical disk includes a magneto-optical disk that uses a blue-violet semiconductor laser or a blue-violet SHG laser as a light source for recording / reproducing information.

  Furthermore, in this specification, DVD is a generic term for DVD series optical disks such as DVD-ROM, DVD-Video, DVD-Audio, DVD-RAM, DVD-R, DVD-RW, DVD + R, DVD + RW, and the like. Is a general term for CD-series optical disks such as CD-ROM, CD-Audio, CD-Video, CD-R, CD-RW and the like. The recording density is highest in the high-density optical disc, and then decreases in the order of DVD and CD.

The optical pickup device according to claim 1, wherein a first light source that emits a first light flux having a wavelength λ1 (380 nm ≦ λ1 ≦ 420 nm) and a second light flux that emits a second light flux having a wavelength λ2 (570 nm ≦ λ2 ≦ 820 nm). A light source, a first objective lens for condensing the first light flux on the information recording surface of the first optical information recording medium, and a plastic for condensing the second light flux on the information recording surface of the second optical information recording medium An optical pickup device having a second objective lens made of:
At least the material constituting the second objective lens has a transmittance of 85% or more at an axial thickness of 3 mm of a light beam having a wavelength of 405 nm.

  In the case where the objective lens is made of the same plastic as that used in a general plastic objective lens for CD / DVD, it is known that deterioration occurs due to irradiation with blue-violet laser light for a long period of time. However, in an optical pickup device that records and / or reproduces information in a manner compatible with a high-density optical disc and DVD / CD, an objective lens for DVD / CD that is not originally arranged in the optical path of blue-violet laser light. It was confirmed that the (second objective lens) was deteriorated.

  As a result of diligent research, the inventors of the present invention, for example, to simplify the configuration, the optical path of blue-violet laser light for high-density optical discs and the optical path of red laser light for DVDs or infrared laser light for CDs. And even if these are branched using a selection element, leakage light of about several percent occurs mutually, and blue-violet laser light is incident on the second objective lens for DVD / CD. It was determined that deterioration would occur. Such blue-violet laser light may be incident on the second objective lens due to the reflected light of each part even when the selection element is not used. On the other hand, if the second objective lens for DVD / CD is made of glass, deterioration can be suppressed even after long-term use and stable performance can be maintained, but this leads to high cost. Therefore, in the present invention, the material constituting the second objective lens has a characteristic that the transmittance of a light beam having a wavelength of 405 nm at an axial thickness of 3 mm is 85% or more, thereby balancing the cost and durability. It is intended. That is, DVD. By using a plastic having resistance to blue-violet laser light for the second objective lens for CD, the above-mentioned problems have been solved.

  In the 2nd objective lens of this invention, it is preferable that the resin composition excellent in the light resistance with respect to a short wavelength blue-violet laser and heat resistance is used as a base material. As a first preferred example of such a resin composition, it is preferable to have a resin substrate containing a polymer having an alicyclic structure. Of the resins described later, a resin having a transmittance of 85% or more at a thickness of 3 mm on the axis of a light beam having a wavelength of 405 nm may be selected. It is more preferable to use a material whose transmittance does not decrease by 5% or more even when a light beam having a wavelength of 405 nm is continuously irradiated for 24 hours or more.

  As the polymer having an alicyclic structure, the repeating unit (a) having an alicyclic structure represented by the following general formula (1), the following general formula (2) and / or Or the repeating unit (b) having a chain structure represented by the following general formula (3) is contained so that the total content is 90% by weight or more, and the content of the repeating unit (b) is 1% by weight. % Or more and less than 10% by weight is preferred.

式（１）中、Ｘは脂環式炭化水素基であり、式（１）、式（２）、及び式（３）中、Ｒ１〜Ｒ１３は、それぞれ独立に水素原子、鎖状炭化水素基、ハロゲン原子、アルコキシ基、ヒドロキシ基、エーテル基、エステル基、シアノ基、アミド基、イミド基、シリル基、及び極性基（ハロゲン原子、アルコキシ基、ヒドロキシ基、エーテル基、エステル基、シアノ基、アミド基、イミド基、又はシリル基）で置換された鎖状炭化水素基である。その中でも水素原子又は炭素原子数１〜６個の鎖状炭化水素基の場合が、耐熱性、低吸水性に優れるので好ましい。ハロゲン原子としては、フッ素原子、塩素原子、臭素原子、及びヨウ素原子を挙げることができる。極性基で置換された鎖状炭化水素基としては、例えば炭素原子数１〜２０、好ましくは１〜１０、より好ましくは１〜６のハロゲン化アルキル基が挙げられる。鎖状炭化水素基としては、例えば炭素原子数１〜２０、好ましくは１〜１０、より好ましくは１〜６のアルキル基；炭素原子数２〜２０、好ましくは２〜１０、より好ましくは２〜６のアルケニル基が挙げられる。

In Formula (1), X is an alicyclic hydrocarbon group, and in Formula (1), Formula (2), and Formula (3), R1 to R13 are each independently a hydrogen atom or a chain hydrocarbon group. , Halogen atom, alkoxy group, hydroxy group, ether group, ester group, cyano group, amide group, imide group, silyl group, and polar group (halogen atom, alkoxy group, hydroxy group, ether group, ester group, cyano group, An amide group, an imide group, or a silyl group). 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 the general 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, more preferably 5 to 7. is there. 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 the general formula (3),... Represents a carbon-carbon saturated or carbon-carbon unsaturated bond in the main chain. If transparency and heat resistance are strongly required, the inclusion of an unsaturated bond. The rate is usually 10% or less, preferably 5% or less, and more preferably 3% or less, of all the carbon-carbon bonds constituting the main chain.

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

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

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

  In general formula (4), general formula (5), and general formula (6), Ra, Rb, Rc, Rd, Re, Rf, Rg, Rh, Ri, Rj, Rk, Rl, Rm, and Rn are respectively A hydrogen atom or a lower chain hydrocarbon group is independently shown, 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 of the chain structure represented by the general formula (2) and the general formula (3), the repeating unit of the chain structure represented by the general formula (3) is more preferable in the hydrocarbon-based weight obtained. Excellent combined strength characteristics.

  In the present invention, the hydrocarbon copolymer is represented by the repeating unit (a) having an alicyclic structure represented by the general formula (1), the general formula (2) and / or the general formula (3). The total content of the chain-structured repeating unit (b) 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.

  Furthermore, it is preferable that the chain length of the repeating unit (a) has a specific distribution. Specifically, when A = (weight average molecular weight of repeating unit chain having an alicyclic structure) and C = (number average molecular weight of repeating unit chain having an alicyclic structure), A / C is preferable. Is 1.3 or more, more preferably 1.3 to 8, and most preferably 1.7 to 6. When A / C is excessively small, the degree of block increases, and when it is excessively large, the degree of randomness increases, and in any case, low birefringence is inferior.

  The molecular weight of the alicyclic hydrocarbon copolymer of the present invention is 1,000 in terms of polystyrene (or polyisoprene) converted weight average molecular weight (Mw) measured by gel permeation chromatography (hereinafter, GPC). In the range of ˜1,000,000, preferably 5,000 to 500,000, more preferably 10,000 to 300,000, and most preferably 50,000 to 250,000. If the weight average molecular weight (Mw) of the alicyclic hydrocarbon copolymer is excessively small, the strength characteristics of the molded product are inferior. Conversely, if the molecular weight is excessively large, the birefringence of the molded product increases.

  The molecular weight distribution of such a copolymer can be appropriately selected according to the purpose of use, but the ratio (Mw) of polystyrene (or polyisoprene) -converted weight average molecular weight (Mw) and number average molecular weight (Mn) measured by GPC. / Mn), usually 2.5 or less, preferably 2.3 or less, more preferably 2 or less. When Mw / Mn is in this range, mechanical strength and heat resistance are highly balanced.

  The glass transition temperature (Tg) of the copolymer may be appropriately selected according to the purpose of use, but is usually 50 ° C to 250 ° C, preferably 70 ° C to 200 ° C, more preferably 90 ° C to 180 ° C. .

(Method for producing alicyclic hydrocarbon-based copolymer)
The method for producing an alicyclic hydrocarbon-based copolymer is as follows: (1) copolymerizing an aromatic vinyl compound with another monomer that can be copolymerized, and hydrogenating the 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.

  When the alicyclic hydrocarbon copolymer is produced by the above method, other monomer (b ′) copolymerizable with the aromatic vinyl compound and / or the alicyclic vinyl compound (a ′). The repeating unit derived from the compound (a ′) in the copolymer is D = (weight average molecular weight of the repeating unit chain derived from the aromatic vinyl compound and / or the alicyclic vinyl compound). , E = (weight average molecular weight of hydrocarbon copolymer (Mw) × (number of repeating units derived from aromatic vinyl compound and / or alicyclic vinyl compound / all repeats constituting hydrocarbon copolymer) The main chain of the copolymer having a chain structure in which D is 30% or less, preferably 20% or less, more preferably 15% or less, and most preferably 10% or less of E. Insaturation of aromatic rings and cycloalkene rings Carbon ring - can be obtained efficiently by a method for hydrogenating carbon-carbon unsaturated bond. When D is out of the above range, the low birefringence of the resulting alicyclic hydrocarbon copolymer is poor.

  The method (1) is preferable because an alicyclic hydrocarbon copolymer can be obtained more efficiently.

  The copolymer before hydrogenation further has a D / F when F = (number average molecular weight of a chain of repeating units derived from an aromatic vinyl compound and / or an alicyclic vinyl compound). A certain range is preferable. Specifically, D / F is preferably 1.3 or more, more preferably 1.3 or more and 8 or less, and most preferably 1.7 or more and 6 or less. When D / F is outside this range, the low birefringence of the resulting alicyclic hydrocarbon copolymer is poor.

  The weight average molecular weight and number average molecular weight of the chain of repeating units derived from the above compound (a ′) are, for example, unsaturated two in the main chain of the aromatic vinyl copolymer described in the document Macromolecules 1983, 16, 1925-1928. It can be confirmed by, for example, a method of measuring the molecular weight of the aromatic vinyl chain taken out by reductive decomposition after adding a heavy bond with ozone.

  The molecular weight of the copolymer before hydrogenation is 1,000 to 1,000,000, preferably 5,000 to 500,000 in terms of polystyrene (or polyisoprene) equivalent weight average molecular weight (Mw) measured by GPC. More preferably, it is in the range of 10,000 to 300,000. When the weight average molecular weight (Mw) of the copolymer is excessively small, the strength characteristics of the molded product of the alicyclic hydrocarbon copolymer obtained therefrom are inferior. Conversely, when the copolymer is excessively large, the hydrogenation reactivity is inferior.

  Specific examples of the aromatic vinyl compound used in the method (1) include, for example, styrene, α-methylstyrene, α-ethylstyrene, α-propylstyrene, α-isopropylstyrene, α-t-butylstyrene. 2-methylstyrene, 3-methylstyrene, 4-methylstyrene, 2,4-diisopropylstyrene, 2,4-dimethylstyrene, 4-t-butylstyrene, 5-t-butyl-2-methylstyrene, monochlorostyrene , Dichlorostyrene, monofluorostyrene, 4-phenylstyrene and the like, and styrene, 2-methylstyrene, 3-methylstyrene, 4-methylstyrene and the like are preferable.

  Specific examples of the alicyclic vinyl compound used in the method (2) include, for example, cyclobutylethylene, cyclopentylethylene, cyclohexylethylene, cycloheptylethylene, cyclooctylethylene, norbornylethylene, dicyclohexylethylene, α -Methylcyclohexylethylene, α-t-butylcyclohexylethylene, cyclopentenylethylene, cyclohexenylethylene, cycloheptenylethylene, cyclooctenylethylene, cyclodecenylethylene, norbornenylethylene, α-methylcyclohexenylethylene, and α -T-butylcyclohexenylethylene etc. are mentioned, Among these, cyclohexylethylene and (alpha) -methylcyclohexylethylene are preferable.

  These aromatic vinyl compounds and alicyclic vinyl compounds can be used alone or in combination of two or more.

  Other monomers that can be copolymerized are not particularly limited, but chain vinyl compounds and chain conjugated diene compounds are used. When chain conjugated dienes are used, the operability in the production process is excellent. The resulting alicyclic hydrocarbon copolymer is excellent in strength properties.

  Specific examples of the chain vinyl compound include chain olefin monomers such as ethylene, propylene, 1-butene, 1-pentene and 4-methyl-1-pentene; 1-cyanoethylene (acrylonitrile), 1-cyano- Nitrile monomers such as 1-methylethylene (methacrylonitrile) and 1-cyano-1-chloroethylene (α-chloroacrylonitrile); 1- (methoxycarbonyl) -1-methylethylene (methacrylic acid methyl ester), 1- (Ethoxycarbonyl) -1-methylethylene (methacrylic acid ethyl ester), 1- (propoxycarbonyl) -1-methylethylene (methacrylic acid propyl ester), 1- (butoxycarbonyl) -1-methylethylene (methacrylic) Acid butyl ester), 1-methoxycarboni (Meth) acrylic acid such as ethylene (acrylic acid methyl ester), 1-ethoxycarbonylethylene (acrylic acid ethyl ester), 1-propoxycarbonylethylene (acrylic acid propyl ester), 1-butoxycarbonylethylene (acrylic acid butyl ester) Ester monomers, 1-carboxyethylene (acrylic acid), 1-carboxy-1-methylethylene (methacrylic acid), unsaturated fatty acid monomers such as maleic anhydride, and the like are mentioned, among which chain olefin monomers are preferable, Most preferred are ethylene, propylene and 1-butene.

  Examples of the chain conjugated diene include 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, 1,3-hexadiene, and the like. Of these chain vinyl compounds and chain conjugated dienes, chain conjugated dienes are preferable, and butadiene and isoprene are particularly preferable. These chain vinyl compounds and chain conjugated dienes can be used alone or in combination of two or more.

  These chain vinyl compounds can be used alone or in combination of two or more.

(Method of hydrogenating unsaturated bonds)
When conducting hydrogenation reactions such as carbon-carbon double bonds of unsaturated rings such as aromatic rings and cycloalkene rings of the copolymer before hydrogenation, and unsaturated bonds of the main chain, the reaction method and reaction form are special. There is no particular limitation, and it may be carried out according to a known method. However, a hydrogenation method that can increase the hydrogenation rate and has little polymer chain scission reaction that occurs simultaneously with the hydrogenation reaction is preferable. The method is performed using a catalyst containing at least one metal selected from cobalt, iron, titanium, rhodium, palladium, platinum, ruthenium, and rhenium. 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 carrier include activated carbon, silica, alumina, calcium carbide, titania, magnesia, zirconia, diatomaceous earth, silicon carbide and the like. The supported amount of the catalyst is usually 0.01 to 80% by weight, preferably 0. The range is from 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. Examples of the nickel, cobalt, titanium, or iron compound include acetylacetone salts, naphthene salts, cyclopentadienyl compounds, cyclopentadienyl dichloro compounds, and the like of various metals. As the organic aluminum compound, alkylaluminum such as triethylaluminum and triisobutylaluminum, aluminum halide such as diethylaluminum chloride and ethylaluminum dichloride, alkylaluminum hydride such as diisobutylaluminum hydride and the like are preferably used.

  As an example of the organometallic complex catalyst, a metal complex such as a γ-dichloro-π-benzene complex, a dichloro-tris (triphenylphosphine) complex, a hydrido-chloro-triphenylphosphine) complex of each of the above metals is 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, preferably on the basis of weight with respect to the polymer. 0.05 to 50 parts, more preferably 0.1 to 30 parts.

  The hydrogenation reaction is usually 10 ° C. to 250 ° C., but preferably 50 ° C. to 200 ° C. because the hydrogenation rate can be increased and the polymer chain scission reaction occurring simultaneously with the hydrogenation reaction can be reduced. More preferably, it is 80 degreeC-180 degreeC. The hydrogen pressure is usually 0.1 MPa to 30 MPa, but in addition to the above reasons, from the viewpoint of operability, it is preferably 1 MPa to 20 MPa, more preferably 2 MPa to 10 MPa.

  The hydrogenation rate of the hydride obtained in this manner is determined by 1H-NMR, as determined by carbon-carbon unsaturated bond of the main chain, carbon-carbon double bond of aromatic ring, carbon-carbon of unsaturated ring. All of the double bonds are usually 90% or more, preferably 95% or more, more preferably 97% or more. When the hydrogenation rate is low, the low birefringence, thermal stability, etc. of the resulting copolymer are lowered.

  The method for recovering the hydride after completion of the hydrogenation reaction is not particularly limited. Usually, after removing the hydrogenation catalyst residue by a method such as filtration or centrifugation, the solvent is removed directly from the hydride solution by drying, the hydride solution is poured into a poor solvent for the hydride, and the hydride A method of coagulating can be used.

  As the polymer having an alicyclic structure, a block copolymer having a polymer block [A] and a polymer block [B] is more preferable. The polymer block [A] contains a repeating unit [1] represented by the following formula (1). The content of the repeating unit [1] in the polymer block [A] is preferably 50 mol% or more, more preferably 70 mol% or more, and particularly preferably 90 mol% or more.

（式中、Ｒ１は水素原子、または炭素数１〜２０のアルキル基を表し、Ｒ２−Ｒ１２はそれぞれ独立に、水素原子、炭素数１〜２０のアルキル基、ヒドロキシル基、炭素数１〜２０のアルコキシ基、またはハロゲン基である。尚、前記Ｒ２ −Ｒ１２は、Ｒ２ 、Ｒ３ 、Ｒ４ 、Ｒ５ 、Ｒ６ 、Ｒ７ 、Ｒ８ 、Ｒ９ 、Ｒ１０、Ｒ１１およびＲ１２である。以降同様。）

(In the formula, R1 represents a hydrogen atom or an alkyl group having 1 to 20 carbon atoms, and R2-R12 each independently represents a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, a hydroxyl group, or a carbon group having 1 to 20 carbon atoms. And R2-R12 is R2, R3, R4, R5, R6, R7, R8, R9, R10, R11 and R12, and so on.

  A preferred structure of the repeating unit [1] represented by the above formula (1) is one in which R1 is hydrogen or a methyl group and R2-R12 are all hydrogen. When the content of the repeating unit [1] in the polymer block [A] is in the above range, transparency and mechanical strength are excellent. The remainder other than the repeating unit [1] in the polymer block [A] is a hydrogenated repeating unit derived from a chain conjugated diene or a chain vinyl compound.

  The polymer block [B] contains the repeating unit [1] and the repeating unit [2] represented by the following formula (2) or / and the repeating unit [3] represented by the following formula (3). The content of the repeating unit [1] in the polymer block [B] is preferably 40 to 95 mol%, more preferably 50 to 90 mol%. When the content of the repeating unit [1] is in the above range, transparency and mechanical strength are excellent. When the molar fraction of the repeating unit [2] in the block [B] is m2 (mol%) and the molar fraction of the repeating unit [3] is m3 (mol%), 2 × m2 + m3 is preferably It is 2 mol% or more, more preferably 5 to 60 mol%, most preferably 10 to 50 mol%.

（式中、Ｒ１３は、水素原子、または炭素数１〜２０のアルキル基を表す。）

(In the formula, R13 represents a hydrogen atom or an alkyl group having 1 to 20 carbon atoms.)

  A preferred structure of the repeating unit [2] represented by the above formula (2) is one in which R13 is hydrogen or a methyl group.

（式中、Ｒ１４およびＲ１５はそれぞれ独立に、水素原子、または炭素数１〜２０のアルキル基を表す。）

(In the formula, R14 and R15 each independently represent a hydrogen atom or an alkyl group having 1 to 20 carbon atoms.)

  A preferred structure of the repeating unit [3] represented by the above formula (3) is one in which R14 is hydrogen and R15 is a methyl group or an ethyl group.

  If the content of the repeating unit [2] or the repeating unit [3] in the polymer block [B] is too small, the mechanical strength is lowered. Therefore, when the content of the repeating unit [2] and the repeating unit [3] is in the above range, transparency and mechanical strength are excellent. The polymer block [B] may further contain a repeating unit [X] represented by the following formula (X). The content of the repeating unit [X] is an amount that does not impair the properties of the block copolymer of the present invention, and preferably 30 mol% or less, more preferably 20 mol% or less, based on the entire block copolymer. It is.

（式中、Ｒ２５は水素原子、または炭素数１〜２０のアルキル基を表し、Ｒ２６はニトリル基、アルコキシカルボニル基、ホルミル基、ヒドロキシカルボニル基、もしくはハロゲン基を表し、Ｒ２７は水素原子を表す。または、Ｒ２６とＲ２７とは相互に結合して、酸無水物基、もしくはイミド基を形成してもよい。）

(Wherein R25 represents a hydrogen atom or an alkyl group having 1 to 20 carbon atoms, R26 represents a nitrile group, an alkoxycarbonyl group, a formyl group, a hydroxycarbonyl group, or a halogen group, and R27 represents a hydrogen atom. Alternatively, R26 and R27 may be bonded to each other to form an acid anhydride group or an imide group.)

  In the block copolymer, the molar fraction of the repeating unit [1] in the polymer block [A] is a, and the molar fraction of the repeating unit [1] in the polymer block [B] is b. It is preferable that there is a relationship of a> b. Thereby, it is excellent in transparency and mechanical strength.

  Further, the block copolymer has a ratio (ma: mb) where the number of moles of all repeating units constituting the block [A] is ma and the number of moles of all repeating units constituting the block [B] is mb. ) Is preferably 5:95 to 95: 5, more preferably 30:70 to 95: 5, and particularly preferably 40:60 to 90:10. When (ma: mb) is in the above range, the mechanical strength and heat resistance are excellent.

  The molecular weight of the block copolymer is a polystyrene (or polyisoprene) equivalent weight average molecular weight (hereinafter referred to as Mw) measured by gel permeation chromatography (hereinafter referred to as GPC) using tetrahydrofuran (THF) as a solvent. In this case, it is preferably in the range of 10,000 to 300,000, more preferably 15,000 to 250,000, and particularly preferably 20,000 to 200,000. When the Mw of the block copolymer is in the above range, the balance of mechanical strength, heat resistance, and moldability is excellent.

  The molecular weight distribution of the block copolymer can be appropriately selected according to the purpose of use, but the ratio (Mw) of polystyrene (or polyisoprene) converted Mw and number average molecular weight (hereinafter referred to as Mn) measured by GPC. / Mn), preferably 5 or less, more preferably 4 or less, particularly preferably 3 or less. When Mw / Mn is in this range, the mechanical strength and heat resistance are excellent.

  The glass transition temperature (hereinafter referred to as Tg) of the block copolymer may be appropriately selected depending on the purpose of use, but is measured on the high temperature side by a differential scanning calorimeter (hereinafter referred to as DSC). The value is preferably 70 ° C to 200 ° C, more preferably 80 ° C to 180 ° C, and particularly preferably 90 ° C to 160 ° C.

  The block copolymer has a polymer block [A] and a polymer block [B]. Even if it is a ([A]-[B]) type diblock copolymer, ([A]- [B]-[A]) type and ([B]-[A]-[B]) type triblock copolymers include polymer block [A] and polymer block [B]. Alternatively, a block copolymer in which a total of 4 or more are alternately connected may be used. Moreover, the block copolymer which these blocks couple | bonded with radial type may be sufficient.

  The block copolymer can be obtained by the following method. As the method, an aromatic vinyl compound or / and a monomer mixture containing an alicyclic vinyl compound having an unsaturated bond in the ring, and a vinyl monomer (excluding an aromatic vinyl compound and an alicyclic vinyl compound) are used. A block having a polymer block containing a repeating unit derived from an aromatic vinyl compound and / or an alicyclic vinyl compound, and a polymer block containing a repeating unit derived from a vinyl monomer by polymerizing the monomer mixture A copolymer is obtained. And a method of hydrogenating an aromatic ring and / or an aliphatic ring of the block copolymer, a monomer mixture containing a saturated alicyclic vinyl compound, and a vinyl monomer (aromatic vinyl compound and alicyclic vinyl compound) A block copolymer having a polymer block containing a repeating unit derived from an alicyclic vinyl compound, and a polymer block containing a repeating unit derived from a vinyl monomer And the like. Especially, what is more preferable as a block copolymer used for this invention can be obtained with the following method, for example.

  (1) As a first method, first, a monomer mixture [a ′] containing 50 mol% or more of an aromatic vinyl compound and / or an alicyclic vinyl compound having an unsaturated bond in the ring is polymerized to obtain an aromatic A polymer block [A ′] containing a repeating unit derived from an aliphatic vinyl compound or / and an alicyclic vinyl compound having an unsaturated bond in the ring is obtained. A monomer mixture containing a vinyl monomer (excluding an aromatic vinyl compound and an alicyclic vinyl compound) in an amount of 2 mol% or more and an aromatic vinyl compound and / or an unsaturated bond in the ring [ a ′] by polymerizing the monomer mixture [b ′] contained in an amount smaller than the proportion in the aromatic vinyl compound or / and the repeating unit derived from the alicyclic vinyl compound and the repeating derived from the vinyl monomer. A polymer block [B ′] containing units is obtained. After obtaining the block copolymer having the polymer block [A ′] and the polymer block [B ′] through at least these steps, the aromatic ring and / or the aliphatic ring of the block copolymer is hydrogenated. Turn into.

  (2) As a second method, first, a polymer containing a repeating unit derived from a saturated alicyclic vinyl compound by polymerizing a monomer mixture [a] containing 50 mol% or more of a saturated alicyclic vinyl compound. A block [A] is obtained. Contains 2 mol% or more of vinyl-based monomers (excluding aromatic vinyl compounds and alicyclic vinyl compounds), and contains saturated alicyclic vinyl compounds in a proportion smaller than the proportion in the monomer mixture [a]. The monomer mixture [b] is polymerized to obtain a polymer block [B] containing a repeating unit derived from a saturated alicyclic vinyl compound and a repeating unit derived from a vinyl monomer. At least through these steps, a block copolymer having the polymer block [A] and the polymer block [B] is obtained.

  Among the above methods, the method (1) is more preferable from the viewpoints of availability of monomers, polymerization yield, ease of introduction of the repeating unit [1] into the polymer block [B ′], and the like. .

  Specific examples of the aromatic vinyl compound in the method (1) include styrene, α-methylstyrene, α-ethylstyrene, α-propylstyrene, α-isopropylstyrene, α-t-butylstyrene, and 2-methylstyrene. 3-methylstyrene, 4-methylstyrene, 2,4-diisopropylstyrene, 2,4-dimethylstyrene, 4-t-butylstyrene, 5-t-butyl-2-methylstyrene, monochlorostyrene, dichlorostyrene, mono Examples include fluorostyrene, 4-phenylstyrene, and the like, and those having a substituent such as a hydroxyl group or an alkoxy group. Of these, styrene, 2-methylstyrene, 3-methylstyrene, 4-methylstyrene and the like are preferable.

  Specific examples of the unsaturated alicyclic vinyl compound in the method (1) include cyclohexenylethylene, α-methylcyclohexenylethylene, α-t-butylcyclohexenylethylene, and the like, and a halogen group and an alkoxy group. Or those having a substituent such as a hydroxyl group.

  These aromatic vinyl compounds and alicyclic vinyl compounds can be used alone or in combination of two or more. In the present invention, any one of the monomer mixtures [a ′] and [b ′] In addition, it is preferable to use an aromatic vinyl compound, and it is more preferable to use styrene or α-methylstyrene.

  The vinyl monomer used in the above method includes a chain vinyl compound and a chain conjugated diene compound.

  Specific examples of the chain vinyl compound include chain olefin monomers such as ethylene, propylene, 1-butene, 1-pentene and 4-methyl-1-pentene. Among these, chain olefin monomers are preferable, and ethylene Most preferred are propylene, 1-butene.

  Examples of the chain conjugated diene include 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, 1,3-hexadiene, and the like. Of these chain vinyl compounds and chain conjugated dienes, chain conjugated dienes are preferable, and butadiene and isoprene are particularly preferable. These chain vinyl compounds and chain conjugated dienes can be used alone or in combination of two or more.

  When polymerizing a monomer mixture containing the above monomers, the polymerization reaction may be carried out by any method such as radical polymerization, anionic polymerization, cationic polymerization, etc., but preferably by anionic polymerization in the presence of an inert solvent. Most preferably, living anionic polymerization is performed.

  Anionic polymerization is usually carried out in the temperature range of 0 ° C. to 200 ° C., preferably 20 ° C. to 100 ° C., particularly preferably 20 ° C. to 80 ° C. in the presence of a polymerization initiator. Examples of the initiator include monoorganolithium such as n-butyllithium, sec-butyllithium, t-butyllithium, hexyllithium, and phenyllithium, dilithiomethane, 1,4-diobane, 1,4-dilithio-2-ethylcyclohexane. A polyfunctional organolithium compound such as can be used.

  Examples of the inert solvent used include aliphatic hydrocarbons such as n-butane, n-pentane, isopentane, n-hexane, n-heptane, and isooctane; cyclopentane, cyclohexane, methylcyclopentane, methylcyclohexane, decalin And alicyclic hydrocarbons such as benzene, toluene and the like, and the use of aliphatic hydrocarbons and alicyclic hydrocarbons is an inert solvent for hydrogenation reaction. Can be used as is. These solvents can be used alone or in combination of two or more, and are usually used at a ratio of 200 to 10,000 parts by weight with respect to 100 parts by weight of all the monomers used.

  When polymerizing each polymer block, a polymerization accelerator, a randomizer, or the like can be used in order to prevent a chain of a certain component from becoming long in each block. In particular, when the polymerization reaction is performed by anionic polymerization, a Lewis base compound or the like can be used as a randomizer. Specific examples of Lewis base compounds include ether compounds such as dimethyl ether, diethyl ether, diisopropyl ether, dibutyl ether, tetrahydrofuran, diphenyl ether, ethylene glycol diethyl ether, ethylene glycol methyl phenyl ether; tetramethylethylenediamine, trimethylamine, triethylamine, pyridine, etc. Tertiary amine compounds; alkali metal alkoxide compounds such as potassium-t-amyl oxide and potassium-t-butyl oxide; phosphine compounds such as triphenylphosphine. These Lewis base compounds can be used alone or in combination of two or more.

  Examples of the method for obtaining a block copolymer by living anionic polymerization include conventionally known sequential addition polymerization reaction method and coupling method. In the present invention, it is preferable to use sequential addition polymerization reaction method.

  When the block copolymer having the polymer block [A ′] and the polymer block [B ′] is obtained by the sequential addition polymerization reaction method, a step of obtaining the polymer block [A ′], and a polymer block The process of obtaining [B ′] is performed sequentially and continuously. Specifically, in the presence of the living anion polymerization catalyst in an inert solvent, the monomer mixture [a ′] is polymerized to obtain a polymer block [A ′], and then the monomer mixture [b ′] is added to the reaction system. To continue the polymerization to obtain a polymer block [B ′] connected to the polymer block [A ′]. Furthermore, if desired, the monomer mixture [a ′] is added again for polymerization, the polymer block [A ′] is connected to form a triblock body, and the monomer mixture [b ′] is added again for polymerization. Then, a tetrablock body in which the polymer blocks [B ′] are connected is obtained.

  The obtained block copolymer is recovered by a known method such as a steam stripping method, a direct desolvation method, or an alcohol coagulation method. In the polymerization reaction, when an inert solvent is used in the hydrogenation reaction, the polymerization solution can be used as it is in the hydrogenation reaction step, so that the block copolymer need not be recovered from the polymerization solution. .

  Of the block copolymer having a polymer block [A ′] and a polymer block [B ′] obtained in the method (1) (hereinafter referred to as a pre-hydrogenation block copolymer), it has the following structure: Those having a repeating unit are preferred.

  The polymer block [A ′] constituting the preferred pre-hydrogenation block copolymer is a polymer block containing 50 mol% or more of the repeating unit [4] represented by the following formula (4).

（式中、Ｒ１６は水素原子、または炭素数１〜２０のアルキル基を表し、Ｒ１７−Ｒ２１は、それぞれ独立に、水素原子、炭素数１〜２０のアルキル基、ヒドロキシル基、炭素数１〜２０のアルコキシ基またはハロゲン基である。尚、上記〔Ｒ１７−Ｒ２１〕は、Ｒ１７、Ｒ１８、・・およびＲ２１を表す。）

(In the formula, R 16 represents a hydrogen atom or an alkyl group having 1 to 20 carbon atoms, and R 17 to R 21 each independently represents a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, a hydroxyl group, or a carbon group having 1 to 20 carbon atoms. (Wherein [R17-R21] represents R17, R18,..., And R21).

  A preferred polymer block [B ′] necessarily contains the repeating unit [4], the repeating unit [5] represented by the following formula (5) and the repeating unit [6] represented by the following formula (6). ] A polymer block containing at least one of the above. Further, when the mole fraction of the repeating unit [4] in the polymer block [A ′] is a ′ and the mole fraction of the repeating unit [4] in the block [B ′] is b ′, a ′> b ′.

（式中、Ｒ２２は水素原子、または炭素数１〜２０のアルキル基を表す。）

(In the formula, R22 represents a hydrogen atom or an alkyl group having 1 to 20 carbon atoms.)

（式中、Ｒ２３は水素原子、または炭素数１〜２０のアルキル基を表し、Ｒ２４は水素原子、炭素数１〜２０のアルキル基またはアルケニル基を表す。）

(In the formula, R23 represents a hydrogen atom or an alkyl group having 1 to 20 carbon atoms, and R24 represents a hydrogen atom, an alkyl group having 1 to 20 carbon atoms or an alkenyl group.)

  Further, the block [B ′] may contain a repeating unit [Y] represented by the following formula (Y).

（式中、Ｒ２８は水素原子、または炭素数１〜２０のアルキル基を表し、Ｒ２９はニトリル基、アルコキシカルボニル基、ホルミル基、ヒドロキシカルボニル基、またはハロゲン基を表し、Ｒ３０は水素原子を表す。または、Ｒ２９とＲ３０とは相互に結合して、酸無水物基、またはイミド基を形成してもよい。）

(In the formula, R28 represents a hydrogen atom or an alkyl group having 1 to 20 carbon atoms, R29 represents a nitrile group, an alkoxycarbonyl group, a formyl group, a hydroxycarbonyl group, or a halogen group, and R30 represents a hydrogen atom. Alternatively, R29 and R30 may be bonded to each other to form an acid anhydride group or an imide group.)

  Furthermore, a preferable block copolymer before hydrogenation is a case where the number of moles of all repeating units constituting the block [A ′] is ma ′ and the number of moles of all repeating units constituting the block [B ′] is mb ′. The ratio (ma ′: mb ′) is 5:95 to 95: 5, more preferably 30:70 to 95: 5, and particularly preferably 40:60 to 90:10. When (ma ′: mb ′) is in the above range, the mechanical strength and heat resistance are excellent.

  The molecular weight of the block copolymer before hydrogenation is preferably 12,000 to 400,000, more preferably 19,000 to 350,000, in terms of polystyrene (or polyisoprene) equivalent Mw measured by GPC using THF as a solvent. Especially preferably, it is the range of 25,000-300,000. When the Mw of the block copolymer is excessively small, the mechanical strength decreases, and when it is excessively large, the hydrogenation rate decreases.

  The molecular weight distribution of the block copolymer before hydrogenation can be appropriately selected depending on the purpose of use, but is the ratio (Mw / Mn) of Mw and Mn in terms of polystyrene (or polyisoprene) measured by GPC, It is 5 or less, more preferably 4 or less, and particularly preferably 3 or less. When Mw / Mn is in this range, the hydrogenation rate is improved.

  The Tg of the block copolymer before hydrogenation may be appropriately selected depending on the purpose of use, but is a measured value on the high temperature side by DSC, 70 ° C to 150 ° C, more preferably 80 ° C to 140 ° C, Especially preferably, it is 90 degreeC-130 degreeC.

  Method and reaction for hydrogenating the carbon-carbon unsaturated bonds of unsaturated rings such as aromatic rings and cycloalkene rings, and unsaturated bonds of main chains and side chains of the block copolymer before hydrogenation There is no particular limitation on the form, and it may be performed according to a known method. However, a hydrogenation method that can increase the hydrogenation rate and has a low polymer chain scission reaction is preferable. For example, in an organic solvent, nickel, cobalt, iron, Examples thereof include a method performed using a catalyst containing at least one metal selected from titanium, rhodium, palladium, platinum, ruthenium, and rhenium. 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 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, and the supported amount of the catalyst is preferably 0.01 to 80% by weight, more preferably It is in the range of 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. As the nickel, cobalt, titanium, or iron compound, for example, acetylacetone salt, naphthenic acid salt, cyclopentadienyl compound, cyclopentadienyl dichloro compound and the like of various metals are used. As the organic aluminum compound, alkylaluminum such as triethylaluminum and triisobutylaluminum, aluminum halide such as diethylaluminum chloride and ethylaluminum dichloride, alkylaluminum hydride such as diisobutylaluminum hydride and the like are preferably used.

As an example of the organometallic complex catalyst, metal complexes such as γ-dichloro-π-benzene complex, dichloro-tris (triphenylphosphine) complex, hydrido-chloro-triphenylphosphine complex of the above metals are used. These hydrogenation catalysts can be used alone or in combination of two or more, and the amount used is preferably 0.01 to 100 parts by weight, more preferably 100 parts by weight of the polymer. 0.05 to 50 parts by weight, particularly preferably 0.1 to 30 parts by weight.
The hydrogenation reaction is usually 10 ° C. to 250 ° C., but is preferably 50 ° C. to 200 ° C., more preferably 80 ° C. to 80 ° C., because the hydrogenation rate can be increased and the polymer chain cleavage reaction can be reduced. 180 ° C. The hydrogen pressure is preferably 0.1 MPa to 30 MPa, but in addition to the above reasons, it is more preferably 1 MPa to 20 MPa, and particularly preferably 2 MPa to 10 MPa from the viewpoint of operability.

  The hydrogenation rate of the block copolymer obtained in this way is determined by 1H-NMR as measured by carbon-carbon unsaturated bonds in the main chain and side chains, and carbon-carbon unsaturation in aromatic rings and cycloalkene rings. Any of the bonds is preferably 90% or more, more preferably 95% or more, and particularly preferably 97% or more. When the hydrogenation rate is low, the low birefringence, thermal stability, etc. of the resulting copolymer are lowered.

  After completion of the hydrogenation reaction, the block copolymer is prepared by removing the hydrogenation catalyst from the reaction solution by a method such as filtration or centrifugation, and then removing the solvent directly by drying. It can be recovered by a method such as pouring into a poor solvent and solidifying.

  Various kinds of compounding agents can be blended into the polymer as necessary. There are no particular limitations on the compounding agents that can be incorporated into the block copolymer, but stabilizers such as antioxidants, heat stabilizers, light stabilizers, weather stabilizers, ultraviolet absorbers, near infrared absorbers, lubricants, Resin modifiers such as 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 of the present invention.

  Among the above compounding agents, an antioxidant, an ultraviolet absorber, and a light resistance stabilizer are preferably blended with the polymer. Examples of the antioxidant include phenolic antioxidants, phosphorus antioxidants, sulfur antioxidants, etc. Among them, 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 reducing 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, but the polymer 100 according to the present invention. Preferably it is 0.001-5 weight part with respect to a weight part, More preferably, it is 0.01-1 weight part.

  Examples of the ultraviolet absorber include 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2,2′-dihydroxy-4-methoxybenzophenone, 2,2′-dihydroxy-4,4′-dimethoxybenzophenone, 2 -Hydroxy-4-methoxy-2'-benzophenone, 2-hydroxy-4-methoxy-5-sulfobenzophenone trihydrate, 2-hydroxy-4-n-octoxybenzophenone, 2,2 ', 4,4'- Benzophenone ultraviolet absorbers such as tetrahydroxybenzophenone, 4-dodecyloxy-2-hydroxybenzophenone, bis (5-benzoyl-4-hydroxy-2-methoxyphenyl) methane; 2- (2′-hydroxy-5′-methyl-) Phenyl) benzotriazole, 2- (2H Benzotriazol-2-yl) -4-methyl-6- (3,4,5,6-tetrahydrophthalimidylmethyl) phenol, 2- (2H-benzotriazol-2-yl) -4-6-bis ( 1-methyl-1-phenylethyl) phenol, 2- (2′-hydroxy-3 ′, 5′-di-tert-butyl-phenyl) benzotriazole, 2- (2′-hydroxy-3′-tertiary) -Butyl-5'-methyl-phenyl) -5-chlorobenzotriazole, 2- (2'-hydroxy-5'-tert-octylphenyl) benzotriazole, 2- (2'-hydroxy-3 ', 5'- Di-tertiary-amylphenyl) benzotriazole, 2- [2′-hydroxy-3 ′-(3 ″, 4 ″, 5 ″, 6 ″ -tetrahydrophthalimidomethyl) -5′-methyl Benzotriazole-based UV absorbers such as benzyl] benzotriazole and 2,2′-methylenebis [4- (1,1,3,3-tetramethylbutyl) -6- (2H-benzotriazol-2-yl) phenol] Etc. Among these, 2- (2′-hydroxy-5′-methyl-phenyl) benzotriazole, 2- (2H-benzotriazol-2-yl) -4-methyl-6- (3,4,5,6- Tetrahydrophthalimidylmethyl) phenol, 2- (2H-benzotriazol-2-yl) -4-6-bis (1-methyl-1-phenylethyl) phenol and the like are preferable from the viewpoints of heat resistance and low volatility. .

  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 of 1000 to 10,000 as measured by GPC using THF as a solvent are preferred, and those having 2000 to 5000 are more preferred. What is 2800-3800 is especially preferable. When Mn is too small, when HALS is blended by heating and melt-kneading into a polymer, a predetermined amount cannot be blended due to volatilization, and foaming and silver streak occur during heat-melt molding such as injection molding. Sex is reduced. 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 excellent in processing stability, low gas generation and transparency can be obtained by setting the HALS Mn in 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-tetramethyl- Polypiperidyl) 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 other piperidine rings are bonded via a triazine skeleton High molecular weight HALS; a polymer of dimethyl succinate and 4-hydroxy-2,2,6,6-tetramethyl-1-piperidineethanol, 1,2,3,4-butanetetracarboxylic acid and 1,2, Between 2,6,6-pentamethyl-4-piperidinol and 3,9-bis (2-hydroxy-1,1-dimethylethyl) -2,4,8,10-tetraoxaspiro [5,5] undecane Examples thereof include high molecular weight HALS in which piperidine rings are bonded through an ester bond, such as a mixed ester product.

  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 UV absorber and HALS with respect to the block copolymer is preferably 0.01 to 20 parts by weight, more preferably 0.02 to 15 parts by weight, and particularly preferably 0 to 100 parts by weight of the polymer. .05 to 10 parts by weight. 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 polymer is lowered, and the transparency of the lens is lowered.

  In addition, by blending the polymer with a soft polymer having the lowest glass transition temperature of 30 ° C. or less, it is possible to maintain high temperature and high temperature for a long time without deteriorating various properties such as transparency, heat resistance, and mechanical strength. Can prevent white turbidity under humidity.

  Specific examples of the soft polymer include olefin-based soft polymers such as polyethylene, polypropylene, ethylene-α-olefin copolymer, ethylene-propylene-diene copolymer (EPDM); polyisobutylene, isobutylene-isoprene rubber, Isobutylene-based soft polymers such as isobutylene-styrene copolymer; 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, styrene-isoprene-styrene block copolymer -Based soft polymers; silicon-containing soft polymers such as dimethylpolysiloxane and diphenylpolysiloxane; acrylic soft polymers such as polybutyl acrylate, polybutyl methacrylate, and polyhydroxyethyl methacrylate; polyethylene oxide, polypropylene oxide, epichlorohydrin rubber, etc. Epoxy soft polymer; Fluorine soft polymer such as vinylidene fluoride rubber and tetrafluoroethylene-propylene rubber; natural rubber, polypeptide, protein, polyester thermoplastic elastomer, vinyl chloride thermoplastic elastomer, polyamide Other soft polymers such as thermoplastic elastomers can be mentioned. 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. In particular, hydrides obtained by hydrogenating carbon-carbon unsaturated bonds of the soft polymers are advantageous in terms of rubber elasticity, mechanical strength, flexibility, and dispersibility. Excellent. The blending amount of the soft polymer varies depending on the type of the compound, but generally, if the blending amount is too large, the glass transition temperature and the transparency of the polymer are greatly lowered and cannot be used as a lens. On the other hand, if the blending amount is too small, the molded product may become clouded under high temperature and high humidity. The amount is preferably 0.01 to 10 parts by weight, more preferably 0.02 to 5 parts by weight, and particularly preferably 0.05 to 2 parts by weight with respect to 100 parts by weight of the block copolymer.

  The method of forming a polymer composition by blending the above compounding agent with a polymer is, for example, a compounding agent in which a block copolymer is melted with a mixer, a twin-screw kneader, a roll, a Brabender, an extruder, or the like. And a method of dissolving and dispersing in a suitable solvent and solidifying. When a twin-screw kneader is used, it is often used after being kneaded and usually extruded in the form of a strand in a molten state and cut into a pellet by a pelletizer.

  As a second preferred example of the resin composition used for the second objective lens of the present invention, a resin composition having a copolymer resin comprising an α-olefin and a cyclic olefin and a light-resistant stabilizer base material is preferably used. Of the resins described later, a resin having a transmittance of 85% or more at a thickness of 3 mm on the axis of a light beam having a wavelength of 405 nm may be selected. It is more preferable to use a material whose transmittance does not decrease by 5% or more even when a light beam having a wavelength of 405 nm is continuously irradiated for 24 hours or more.

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

式中、ｎは０または１であり、ｍは０または正の整数であり、ｋは０または１である。なおｋが１の場合には、ｋを用いて表される環は６員環となり、ｋが０の場合にはこの環は５員環となる。

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.

  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. . 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. 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 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 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). 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 ³¹ are combined with each other to form a methylene group (—CH ₂ — ), An alkylene group of ethylene group (—CH ₂ CH ₂ —) or 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.

ここで、ｑは一般式（II）におけるｑと同じである。上記のような一般式（I）または（III）で表される環状オレフィンとしては、具体的には、ビシクロ−2−ヘプテン誘導体（ビシクロヘプト−2−エン誘導体）、トリシクロ−3−デセン誘導体、トリシクロ−3−ウンデセン誘導体、テトラシクロ−3−ドデセン誘導体、ペンタシクロ−4−ペンタデセン誘導体、ペンタシクロペンタデカジエン誘導体、ペンタシクロ−3−ペンタデセン誘導体、ペンタシクロ−3−ヘキサデセン誘導体、ペンタシクロ−4−ヘキサデセン誘導体、ヘキサシクロ−4−ヘプタデセン誘導体、ヘプタシクロ−5−エイコセン誘導体、ヘプタシクロ−4−エイコセン誘導体、ヘプタシクロ−5−ヘンエイコセン誘導体、オクタシクロ−5−ドコセン誘導体、ノナシクロ−5−ペンタコセン誘導体、ノナシクロ−6−ヘキサコセン誘導体、シクロペンタジエン−アセナフチレン付加物、1,4−メタノ−1,4,4a,9a−テトラヒドロフルオレン誘導体、1,4−メタノ−1,4,4a,5,10,10a−ヘキサヒドロアントラセン誘導体などが挙げられる。
共重合体を構成するα−オレフィンとしては、例えばエチレン、プロピレン、1−ブテン、1−ペンテン、1−ヘキセン、1−オクテン、1−デセン、1−ドデセン、1−テトラデセン、1−ヘキサデセン、1−オクタデセン、1−エイコセンなどの直鎖状α−オレフィン；4−メチル−1−ペンテン、3−メチル−1−ペンテン、3−メチル−1−ブテンなどの分岐状α−オレフィンなどが挙げられる。好ましくは、炭素原子数が2〜20のα−オレフィンが好ましい。このような直鎖状または分岐状のα−オレフィンは置換基で置換されていても良く、また１種単独、或いは２種以上組合わせて用いることができる。

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 derivative, heptacyclo-5-eicosene derivative, heptacyclo-4-eicosene derivative, heptacyclo-5-henecocene derivative, octacyclo-5-docosene derivative, nonacyclo-5-pentacocene derivative, nonacyclo-6-hexacocene derivative, Clopentadiene-acenaphthylene adducts, 1,4-methano-1,4,4a, 9a-tetrahydrofluorene derivatives, 1,4-methano-1,4,4a, 5,10,10a-hexahydroanthracene derivatives, etc. It is done.
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, 1 -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 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.

  The alkyl group is preferably one having 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, an arylureido group; the sulfamoylamino group is preferably an alkylsulfamoylamino group, an arylsulfamoylamino group; Is 2-furyl, 2-thienyl, 2-pyrimidinyl, 2-benzothiazolyl, etc .; the saturated heterocyclic ring is preferably a 5- to 7-membered, 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, 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 .; as spiro compound residue Are spiro [3.3] heptan-1-yl and the like; and the bridged hydrocarbon compound residue is bicyclo [2.2.1] heptan-1-yl, tricyclo [3.3.1.13.7] decane -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.

  The acyclic monomer content in the copolymer 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. Is more preferable.

  The glass transition temperature (Tg) of the polymer or copolymer is preferably in the range of 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-based resin may be a polymer synthesized from one-component cyclic monomer, but preferably a two-component or more cyclic monomer or a copolymer synthesized using a cyclic monomer and an acyclic monomer is selected. This copolymer may be produced using monomers having 100 or more components, but the mixing of monomers is preferably 10 or less in terms of production efficiency and polymerization stability. More preferred is 5 components or less.

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

  As a method for hydrogenating carbon-carbon unsaturated bonds (including aromatic rings) of polymers and copolymers, known methods can be used. Among them, the hydrogenation rate is increased and the hydrogenation reaction is performed. In order to reduce the simultaneous polymer chain scission reaction, hydrogenation is carried out using a catalyst containing at least one metal selected from nickel, cobalt, iron, titanium, rhodium, palladium, platinum, ruthenium and rhenium in an organic solvent. It is preferred to carry out the 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 0.05-60% 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 to 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.

  Moreover, hydrogen pressure is 0.1MPa-30MPa normally, Preferably it is 1MPa-20MPa, More preferably, it is 2MPa-15MPa. 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 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, tetrahydrofuran , Ethers such as 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, methylcyclohexane and dimethylcyclohexane , Aliphatic cyclic hydrocarbons such as decalin, halogenated hydrocarbons such as methylene dichloride, dichloroethane, dichloroethylene, tetrachloroethane, chlorobenzene, and trichlorobenzene, and the like. These may be used as a mixture of two or more. .

  The polymer or copolymer hydrogenated product can be produced by isolating the polymer or copolymer hydrogenated product from the polymer solution and then dissolving it again in the solvent. A method of performing a hydrogenation reaction by adding a hydrogenation catalyst comprising the above organometallic complex and an organoaluminum compound can also be employed. 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 hydride solution 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 is used, the hydrogenation rate can be easily achieved as 90% or more, and can be 95% or more, particularly 99% or more. The polymer or copolymer hydrogenated product thus obtained is It is not easily oxidized and becomes an excellent polymer or copolymer hydrogenated product.

"Antioxidant"
The antioxidant 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, but the polymer 100 according to the present invention. Preferably it is 0.001-5 mass parts with respect to a mass part, More preferably, it is 0.01-1 mass part.

  A conventionally well-known thing can be used as a phenolic antioxidant, 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-t-butylphenyl) butane, 1,3,5-trimethyl-2,4,6-tris (3,5 Di-t-butyl-4-hydroxybenzyl) benzene, tetrakis (methylene-3- (3 ′, 5′-di-t-butyl-4′-hydroxyphenylpropionate) methane [pentaerythrmethyl-tetrakis (3 Alkyl substitution such as-(3,5-di-tert-butyl-4-hydroxyphenylpropionate)], triethylene glycol bis (3- (3-tert-butyl-4-hydroxy-5-methylphenyl) propionate) Phenolic compounds; 6- (4-hydroxy-3,5-di-t-butylanilino) -2,4-bisoctylthio-1,3,5-triazine, 4-bisoctylthio-1,3,5- Triazines such as triazine, 2-octylthio-4,6-bis- (3,5-di-t-butyl-4-oxyanilino) -1,3,5-triazine Jin 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) What diphosphite compounds and the like. 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 stabilizer 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 the hindered amine light stabilizers (hereinafter referred to as HALS), those having a Mn in terms of polystyrene measured by GPC using THF as a solvent are preferably from 1000 to 10,000, more preferably from 2000 to 5000, What is 2800-3800 is especially preferable. 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 excellent in processing stability, low gas generation and transparency can be obtained by setting the HALS Mn in 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-tetramethyl (Lu-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 bonded high molecular weight HALS; 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] undeca And high molecular weight HALS in which the piperidine ring is bonded via an ester bond, such as a mixed esterified product with benzene.

  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 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. 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, and the transparency of the lens is lowered.

  In addition, by blending the resin composition with a compound having the lowest glass transition temperature of 30 ° C. or lower, it is possible to increase the temperature and temperature for a long time without deteriorating various properties such as transparency, heat resistance and mechanical strength. It can prevent white turbidity in humidity environment.

  There is provided a resin composition comprising a resin composition and at least one compounding agent selected from the group consisting of (1) a soft polymer and (2) an alcoholic compound. 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 Copolymers, isoprene / styrene / block copolymers, diene-based soft polymers such as styrene / isoprene / styrene / block copolymers, and silicon-containing soft polymers such as dimethylpolysiloxane, diphenylpolysiloxane, and dihydroxypolysiloxane. , Polybutyl acrylate, polybutyl methacrylate, polyhydroxyethyl methacrylate, polyacrylamide, polyacrylonitrile, soft polymers composed of α, β-unsaturated acid such as butyl acrylate / styrene copolymer, polyvinyl alcohol, polyvinyl acetate, poly Soft polymers composed of unsaturated alcohols such as vinyl stearate and vinyl acetate / styrene copolymers and amines or acyl derivatives or acetals thereof, ethylene oxide, polypropylene oxide, epichrome Epoxy soft polymers such as hydrin rubber, fluorinated soft polymers such as vinylidene fluoride rubber and tetrafluoroethylene-propylene rubber, natural rubber, polypeptide, protein, polyester thermoplastic elastomer, vinyl chloride Other soft polymers such as thermoplastic elastomers and polyamide-based thermoplastic elastomers can be used. These soft polymers may have a cross-linked structure or may have a functional group introduced by a modification reaction.

  Of the above-mentioned soft polymers, diene-based soft polymers are preferable. In particular, hydrides obtained by hydrogenating carbon-carbon unsaturated bonds of the soft polymers are 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-nonylphenyl) Xy) -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. Although the molecular weight of these polyhydric alcohol compounds is not particularly limited, 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; particles of natural polymer compounds 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 element 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, Bon, 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 of (1) to (3) is determined by the combination of the compound compounded with the alicyclic hydrocarbon copolymer, but generally, if the compounding amount is too large, the glass transition temperature and transparency of the composition are transparent. 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. As a compounding quantity, it is 0.01-10 mass parts normally with respect to 100 mass parts of alicyclic hydrocarbon-type copolymers, Preferably it is 0.02-5 mass parts, Most preferably, it is 0.05-2 mass parts. 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>
If necessary, the resin composition may contain other additives such as UV absorbers, light stabilizers, near-infrared absorbers, coloring agents such as dyes and pigments, lubricants, plasticizers, antistatic agents, and fluorescent whitening. An agent or the like can be blended, and these can be used alone or in admixture of two or more, and the blending amount is appropriately selected within a range not impairing the object of the present invention.

  According to a second aspect of the present invention, in the optical pickup device according to the first aspect of the present invention, the material constituting the first objective lens has a transmittance of 85% or more at an axial thickness of 3 mm of a light beam having a wavelength of 405 nm. It is characterized by that. For example, the plastic described above as a preferred example of the material for the second objective lens may be used as the material for the first objective lens, or glass may be used. It is more preferable that the material does not decrease the transmittance by 5% or more even when the light beam having a wavelength of 405 nm is continuously irradiated for 24 hours or more.

  According to a third aspect of the present invention, in the optical pickup device according to the first or second aspect of the present invention, the material constituting the second objective lens has a transmittance at a thickness of 3 mm on the axis of a light beam having a wavelength of 655 nm or a wavelength of 780 nm. It is characterized by being 85% or more. More preferably, it is 90% or more. Since the second objective lens is preferably used as an objective lens for CD or DVD, it is preferable that the transmittance of the light beam used for the optical disc is high.

The optical pickup device according to claim 4 is the invention according to any one of claims 1 to 3,
A first rising mirror that reflects the second light flux and enters the second objective lens; and a second rising mirror that reflects the first light flux and enters the first objective lens;
The optical path of the first light flux from the first light source to the first optical information recording medium and the optical path of the second light flux from the second light source to the second optical information recording medium are partially common. And
The first rising mirror is disposed in a common optical path of the first light flux and the second light flux, reflects the second light flux, and transmits the first light flux,
The second rising mirror is disposed in a dedicated optical path of the first light beam, and reflects the first light beam that has passed through the first rising mirror. When the optical pickup device has such a configuration, a part of the first light beam is reflected by the first raising mirror, and the possibility that the first light beam enters the second objective lens is increased. The effect of the present invention to solve the problems caused thereby becomes more remarkable.

  According to a fifth aspect of the present invention, in the invention according to any one of the first to fourth aspects, the wavelength of the second light beam emitted from the second light source is λ2 (550 nm ≦ λ2 ≦ 680 nm). And a third light source that emits a third light beam having a wavelength λ3 (750 nm ≦ λ2 ≦ 820 nm), the second objective lens has an optical path difference providing structure, and the second light beam is used as the second light information. In addition to condensing on the information recording surface of the recording medium, the third light flux is condensed on the information recording surface of the third optical information recording medium. In addition, the optical path difference providing structure in this specification is a general term for structures that add an optical path difference to an incident light beam. The optical path difference providing structure also includes a phase difference providing structure for providing a phase difference. The phase difference providing structure includes a diffractive structure. The optical path difference providing structure has a step, preferably a plurality of steps. This step adds an optical path difference and / or phase difference to the incident light flux. The optical path difference added by the optical path difference providing structure may be an integer multiple of the wavelength of the incident light beam or a non-integer multiple of the wavelength of the incident light beam. The steps may be arranged with a periodic interval in the direction perpendicular to the optical axis, or may be arranged with a non-periodic interval in the direction perpendicular to the optical axis. In the invention of claim 4, the optical path difference providing structure utilizes the difference in wavelength between the second light beam and the third light beam, and the difference in thickness between the transparent substrates of the second optical information recording medium and the third optical information recording medium. Therefore, it is preferable to make compatibility possible by using the property.

  According to a sixth aspect of the present invention, in the invention according to any one of the first to fifth aspects, the first objective lens and the second objective lens are separate bodies.

  An optical pickup device according to a seventh aspect is characterized in that, in the invention according to any one of the first to fifth aspects, the first objective lens and the second objective lens are integrated. “The first objective lens and the second objective lens are integrated” means that the first objective lens and the second objective lens are fused (for example, the first objective lens and the second objective lens). The first objective lens and the second objective lens are separately molded, and later integrated by bonding or fitting, for example. Both cases are included.

  An optical pickup device according to an eighth aspect of the present invention is the optical pickup device according to any one of the first to seventh aspects, wherein the first objective lens causes the first light beam to be incident on an information recording surface of the first optical information recording medium. Information is recorded by condensing light. Since the recording optical pickup device requires strong power of the first light flux, the intensity of leakage light is increased. Therefore, the second objective lens can be formed using the plastic according to claim 1. preferable.

  The objective lens of Claim 9 is used as a 2nd objective lens in the optical pick-up apparatus in any one of Claims 1-8.

  As the first optical information recording medium, BD or HD is preferable. As the second optical information recording medium, DVD or CD is preferable. Accordingly, the first objective lens is preferably dedicated to BD or HD or compatible, and the second objective lens is preferably dedicated to DVD or CD or compatible.

  In this specification, the objective lens is, in a narrow sense, a light collecting action that is arranged to face the optical information recording medium at the position closest to the optical information recording medium when the optical information recording medium is loaded in the optical pickup device. In a broad sense, it refers to a lens group that can be operated at least in the optical axis direction by an actuator together with the lens.

  According to the present invention, in order to perform information recording and / or reproduction with respect to different optical information recording media, an optical pickup device capable of sharing an optical system while exhibiting stable performance for a long period of time, and the same An objective lens to be used can be provided.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The optical pickup device PU1 according to the present embodiment can be particularly incorporated into a thin optical disk drive device. FIG. 1 is a perspective view showing a schematic configuration of an optical pickup device PU1 capable of recording and / or reproducing information with respect to a BD and a DVD. FIG. 2 is a plan view of the optical pickup device PU1.

  The optical pickup device PU1 has two rising mirrors M1 and M2. The first rising mirror M1 is disposed in a common optical path of the first light beam emitted from the semiconductor laser LD1 and the second light beam emitted from the semiconductor laser LD2, and reflects the second light beam on the reflection surface coated with the dichroic film. The first light flux is transmitted. The second raising mirror M2 is disposed in the dedicated optical path for the first light flux, and reflects the first light flux that has passed through the first raising mirror M1 on the reflecting surface. The second raising mirror M2 may cover the dichroic film so as to transmit the second light beam, but basically only the first light beam needs to be reflected, and thus may be a normal mirror. The materials constituting the first objective lens OBJ1 and the second objective lens OBJ2 are both plastics resistant to blue-violet laser light, and the transmittance at a thickness of 3 mm on the axis by a light beam having a wavelength of 405 nm is 85% or more. It is. Furthermore, it is preferable that the material forming the second objective lens OBJ2 has a transmittance of 85% or more at a thickness of 3 mm on the axis by a light beam having a wavelength of 655 nm. In the present embodiment, the first objective lens OBJ1 and the second objective lens OBJ2 are separate bodies. The common optical path is from the dichroic prism DP to the first rising mirror M1, and the exclusive optical path of the first light flux is from the first rising mirror M1 to the optical disk.

  1 and 2, when recording and / or reproducing information on a BD, a semiconductor laser LD1 (wavelength λ1 = 380 nm to 420 nm) as a first light source is caused to emit light. The light beam emitted from the semiconductor laser LD1 passes through the dichroic prism DP, passes through the polarization beam splitter PBS, passes through the collimator lens COL, becomes a parallel light beam, passes through the λ / 4 wavelength plate QWP, and first stands. The light passes through the raising mirror M1, is reflected by the second raising mirror M2, is collected by the first objective lens unit OBJ1, and passes through the protective layer (thickness t1 = 0.03 to 0.13 mm) of the BD. The light is focused on the information recording surface to form a focused spot.

  The light beam modulated and reflected by the information pits on the information recording surface again passes through the first objective lens unit OBJ1, is reflected by the second rising mirror M2, and is reflected by the first rising mirror M1 and the λ / 4 wavelength plate QWP. Since the light passes through the collimating lens COL, is reflected by the polarization beam splitter PBS, and is incident on the light receiving surface of the photodetector PD, information is recorded and / or reproduced with respect to the BD using the output signal. Can do.

  On the other hand, when recording and / or reproducing information on a DVD, a semiconductor laser LD2 (wavelength λ2 = 550 nm ≦ λ2 ≦ 680 nm) as a second light source is caused to emit light. The light beam emitted from the semiconductor laser LD2 is reflected by the dichroic prism DP, passes through the polarization beam splitter PBS, passes through the collimating lens COL, becomes a parallel light beam, passes through the λ / 4 wavelength plate QWP, and is first standing. Reflected by the raising mirror M1, condensed by the second objective lens portion OBJ2, and condensed on the information recording surface via the DVD protective layer (thickness t2 = 0.5 to 0.7 mm). A focused spot is formed.

  The light beam modulated and reflected by the information pits on the information recording surface again passes through the second objective lens portion OBJ2, is reflected by the first rising mirror M1, and passes through the λ / 4 wavelength plate QWP and the collimating lens COL. Then, since it is reflected by the polarization beam splitter PBS and is incident on the light receiving surface of the photodetector PD, information can be recorded and / or reproduced on the DVD using the output signal.

  Here, since the first raising mirror M1 close to the light source is a mirror that reflects the second luminous flux (red luminous flux) for DVD, the second luminous flux is reflected by the first raising mirror M1, and the second objective. The light enters the lens OBJ2. On the other hand, the first light beam for BD (blue-violet light beam) basically passes through the first rising mirror M1, but not all the first light beam is transmitted, and a part of the first light beam is first raised. Reflected by the raising mirror M1. Therefore, when recording / reproducing BD, the first light beam is irradiated not only on the first objective lens OBJ1 for BD but also on the second objective lens OBJ2 for DVD. This becomes the leakage light of the first light flux.

  According to the present embodiment, since the second objective lens portion OBJ2 is formed of a resin material having an ultraviolet resistant effect, even when a part of the light flux having the wavelength λ1 is reflected from the first rising mirror M1. Deterioration caused thereby is suppressed, and stable optical performance can be exhibited over a long period of time.

  In the above example, the first objective lens OBJ1 is dedicated to BD and the second objective lens OBJ2 is dedicated to DVD. However, the present invention is not limited to such a combination. The first objective lens OBJ1 may be dedicated to HD or may be compatible with BD / HD. Further, the second objective lens OBJ2 may be dedicated to CD or DVD / CD compatible. In this case, a third light source capable of emitting a light beam having a wavelength λ3 = 750 nm ≦ λ2 ≦ 820 nm by providing a diffraction structure as an optical path difference providing structure on the optical surface of the second objective lens OBJ2 and using the semiconductor laser LD2 as two lasers in one package Is preferably further provided.

  Furthermore, in the present embodiment, the first objective lens OBJ1 and the second objective lens OBJ2 are separate bodies, but they may be integrated by fitting, bonding, or the like. For example, as shown in FIG. 3, the second objective lens OBJ2 may have a rectangular plate-like flange portion FL2. In such a case, the separately formed first objective lens OBJ1 is combined with the stepped portion ST of the opening HL formed in the flange portion FL2 so that the flange portion FL2 is held. The first objective lens and the second objective lens may be integrated by integral molding. The effective diameters of the first objective lens OBJ1 and the second objective lens OBJ2 are preferably substantially equal to each other.

  Alternatively, as shown in FIG. 4, the second objective lens OBJ2 may form a notch CT2 having a stepped portion ST2 in the rectangular plate-shaped flange portion FL2. In such a case, the first objective lens OBJ1 is assembled from the direction orthogonal to the optical axis so that the flange portion FL1 is held in the stepped portion ST2 in the notch CT2, and is integrated by bonding or the like, so that the first objective lens OBJ1 is integrated. And the second objective lens OBJ2 can be formed as an integrated optical element OE.

  As shown in FIG. 5, the flange portion FL1 of the first objective lens OBJ1 may be supported on the upper surface of the flange portion FL2 without forming the stepped portion ST2 in the opening HL2 or the notch CT2. Alternatively, although not shown, the first objective lens OBJ1 and the second objective lens OBJ2 may be integrated by assembling them on separate holding members (a rectangular plate shape similar to the flange portion FL2 in FIG. 3). good. In any case, it is preferable that the holding member has an opening, and the objective lens unit is fitted therein.

  FIG. 6 is a perspective view of the optical pickup device PU2 according to the second embodiment. In the present embodiment, a half mirror monitor mirror MM capable of transmitting a part of the first light beam is disposed between the semiconductor laser LD1 and the dichroic prism DP, compared to the above-described embodiment, A power monitor PM is arranged behind the monitor mirror MM. The power monitor PM receives the first light beam that has passed through the monitor mirror MM, and performs drive control of the semiconductor laser LD1 in accordance with the amount of light received.

  According to the present embodiment, since the first light beam emitted from the semiconductor laser LD1 is bent at an acute angle by the monitor mirror MM, the output of the semiconductor laser LD1 is monitored by the power monitor PM disposed behind the first light beam. However, the optical pickup device PU2 can be made compact.

  The present invention has been described above with reference to the embodiments. However, the present invention should not be construed as being limited to the above-described embodiments, and can be modified or improved as appropriate.

It is a perspective view which shows schematic structure of optical pick-up apparatus PU1. It is a top view which shows schematic structure of optical pick-up apparatus PU1. It is a perspective view which shows the modification of a 1st objective lens and a 2nd objective lens. It is a perspective view which shows another modification of a 1st objective lens and a 2nd objective lens. It is a figure which shows the modification of a 1st objective lens and a 2nd objective lens. It is a perspective view which shows schematic structure of optical pick-up apparatus PU2.

Explanation of symbols

COL Collimating lens CT2 Notch DP Dichroic prism FL1 Flange part FL2 Flange part HL Opening HL2 Opening LD1 Semiconductor laser LD2 Semiconductor laser M1 First raising mirror M2 Second raising mirror MM Monitor mirror OBJ1 First objective lens OBJ2 Second objective lens OE Integrated optical element PBS Polarizing beam splitter PD Photodetector PM Power monitor PU1 Optical pickup device PU2 Optical pickup device QWP λ / 4 wavelength plate ST Stepped portion ST2 Stepped portion

Claims (9)

A first light source that emits a first light beam with a wavelength λ1 (380 nm ≦ λ1 ≦ 420 nm), a second light source that emits a second light beam with a wavelength λ2 (570 nm ≦ λ2 ≦ 820 nm), and the first light beam as a first light. An optical pickup device having a first objective lens for condensing on an information recording surface of an information recording medium and a plastic second objective lens for condensing the second light flux on an information recording surface of a second optical information recording medium Because
At least the material constituting the second objective lens has a transmittance of 85% or more at a thickness of 3 mm on the axis of a light beam having a wavelength of 405 nm.   2. The optical pickup device according to claim 1, wherein the material constituting the first objective lens has a transmittance of 85% or more at a thickness of 3 mm on the axis of a light beam having a wavelength of 405 nm.   3. The optical pickup device according to claim 1, wherein the material constituting the second objective lens has a transmittance of 85% or more at a thickness of 3 mm on the axis of a light beam having a wavelength of 655 nm or a wavelength of 780 nm. A first rising mirror that reflects the second light flux and enters the second objective lens; and a second rising mirror that reflects the first light flux and enters the first objective lens;
The optical path of the first light flux from the first light source to the first optical information recording medium and the optical path of the second light flux from the second light source to the second optical information recording medium are partially common. And
The first rising mirror is disposed in a common optical path of the first light flux and the second light flux, reflects the second light flux, and transmits the first light flux,
The second rising mirror is disposed in a dedicated optical path of the first light flux, and reflects the first light flux that has passed through the first raising mirror. The optical pickup device described in 1.   The wavelength of the second light beam emitted from the second light source is λ2 (550 nm ≦ λ2 ≦ 680 nm), and further includes a third light source that emits a third light beam of wavelength λ3 (750 nm ≦ λ2 ≦ 820 nm). The second objective lens has an optical path difference providing structure, condenses the second light flux on the information recording surface of the second optical information recording medium, and concentrates the third light flux on the third optical information recording medium. The optical pickup device according to claim 1, wherein the optical pickup device collects light on an information recording surface.   6. The optical pickup device according to claim 1, wherein the first objective lens and the second objective lens are separate bodies.   6. The optical pickup device according to claim 1, wherein the first objective lens and the second objective lens are integrated.   8. The information recording according to claim 1, wherein the first objective lens records information by condensing the first light flux on an information recording surface of the first optical information recording medium. The optical pickup device described.   The objective lens used as a 2nd objective lens in the optical pick-up apparatus in any one of Claims 1-8.

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