JP2008170990A - Manufacturing method of wavelength plate for laser optical system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wavelength plate for an optical information recording/reproducing apparatus which is excellent in initial stage characteristics, is hardly influenced by use environment and manufacture environment and is excellent in long-term reliability and which corresponds to two laser beams of different wavelengths. <P>SOLUTION: In a manufacturing method of the wavelength plate for a laser optical system using a cyclic olefinic resin-containing film subjected to stretching alignment, the cyclic olefinic resin-containing film is subjected to stretching processing so that a value of formula (a), Re(λ)/λ, for two laser beams of different wavelengths [wherein λ denotes a wavelength (nm) of the laser beam and Re(λ) denotes a retardation value (nm) of the laser beam passed through the wavelength plate] is (0.2 to 0.3)+X for the first laser beam and (0.8 to 1.2)+Y for the second laser beam, wherein X is 0 or an integral multiple of 0.5 and Y is 0 or an integer of ≥1. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method for producing a wavelength plate for an optical information recording / reproducing apparatus, which uses a film containing a stretched and oriented cyclic olefin resin and is compatible with two laser beams having different wavelengths.

  An optical disk device is an optical information recording / reproducing device that has been greatly expanded in recent years for reasons such as non-contact, large amount of information per unit volume, high speed accessibility, and low cost. Recording media have been developed. For example, information can be written only once with a laser, such as a compact disc (CD), laser disc (LD), CD-ROM, DVD-ROM, etc. that reproduces pre-recorded information as sound, images or computer programs. CD-R and DVD-R that can reproduce information, magneto-optical disk (MO), DVD-RAM, and DVD-RW that can repeatedly record and reproduce information have been developed.

As an optical system apparatus for recording and / or reproducing information in such an optical information recording / reproducing apparatus, a polarizing beam splitter (PBS) and 1 / are provided in the middle of the optical path from the laser light source to the photodetector. There is known an optical pickup device in which a 4λ wavelength plate (QWP) (hereinafter also referred to as “¼ wavelength plate”) is disposed.
Here, the ¼ wavelength plate gives an optical path difference of λ / 4 (and hence a phase difference of π / 2) between two orthogonal polarization components having a specific wavelength. In the above optical pickup device, linearly polarized light (S wave) is irradiated from a laser light source, passes through PBS, passes through a quarter wavelength plate, becomes linearly polarized light, and is irradiated onto an optical recording medium by a condenser lens. The The return light reflected from the optical recording medium follows the same path again, passes through the quarter-wave plate, circularly polarized light is converted into 90-degree azimuth and becomes linearly polarized light (P wave), passes through PBS, It is comprised so that it may be guide | induced to a detector.
In addition, as a rewritable magneto-optical disk device, light irradiated from a laser light source passes through a polarizer and PBS and is irradiated to the magneto-optical disk, and return light reflected by the magneto-optical disk passes through the PBS again and passes through the photodetector. In some cases, a half-wave plate (hereinafter also referred to as “half-wave plate”) is disposed in the middle of the optical path leading to the optical path.
Here, the half-wave plate is a plate that gives an optical path difference of λ / 2 (thus, a phase difference of π) between two orthogonal polarization components of a specific wavelength.

As such a wave plate, a birefringent mica, quartz, quartz, calcite, a wave plate formed from a single crystal such as LiNbO ₃ , LiTaO _3, and an inorganic substrate from an oblique direction with respect to a base substrate such as a glass substrate Inorganic materials such as a wave plate having a birefringent film on the surface of a base substrate obtained by vapor deposition of a material and a wave plate having an LB (Langmuir-Blodget) film having birefringence are conventionally used.
Also, polycarbonate (PC), triacetyl acetate (TAC), polyvinyl alcohol (PVA), polyvinyl butyral (PVB), polyethylene terephthalate (PET), polypropylene (PP), polyarylate, polysulfone, polyethersulfone, acrylic resin, etc. A film imparted with a function of imparting a retardation to transmitted light by stretching and orienting the transparent resin film (hereinafter referred to as a “retardation film”) is adhered to a glass substrate to maintain flatness and shape, A wave plate held by two glass substrates is also used.
However, when a film obtained by stretching the conventional transparent resin film is used as a retardation film, there may be a problem in optical properties such as transparency and stability of retardation value and durability. Furthermore, the most commonly used retardation film of PC, TAC, PVA or PET has a low glass transition temperature (Tg) and inferior heat resistance, so that reproduction and / or additional recording is performed. However, there is a problem that the process temperature at the time of manufacturing the optical device, for example, the temperature in the soldering or bonding process may be limited, or the characteristics may change due to continuous use.

Recently, DVD as a high-density information recording medium is rapidly spreading. On the other hand, since read-only optical discs such as CD, CD-ROM, and CD-R are already widely used in the market, Optical disc apparatuses are strongly required to be able to perform recording or reproduction on various optical discs of different systems, and are also required to be downsized and reduced in price as application fields expand. And in order to respond | correspond to these requirements, use of the wideband wavelength plate (phase difference plate) for responding to the several laser for reading / writing is proposed (patent document 1: Unexamined-Japanese-Patent No. 2001-101700, Patent Document 2: JP 2001-208913 A).
However, when using a plurality of retardation films to form a broadband wave plate, depending on the usage environment, the retardation value (retardation) of each retardation film may gradually change due to long-term continuous use. However, there is a problem that a fine bonding angle for making a wide band gradually changes, and as a result, good characteristics obtained in the initial stage cannot be maintained.
JP 2001-101700 A JP 2001-208913 A

  The present invention has been made against the background of the above-described prior art, and has excellent initial characteristics, is hardly affected by the use environment and the manufacturing environment, has long-term reliability, and is optical information corresponding to two laser beams having different wavelengths. A wave plate for a recording / reproducing apparatus is provided.

As a result of diligent investigations to solve the above-mentioned problems of the prior art, the present invention has excellent heat resistance, low hygroscopicity, high adhesion to various materials, and excellent cyclic stability. A film containing a resin (hereinafter referred to as “cyclic olefin resin film”) has a value of the following formula (a) with respect to two laser beams having different wavelengths, and (0. 2 to 0.3) + X, and (0.8 to 1.2) + Y for the second laser light (where X is 0 or an integer multiple of 0.5, and Y is The wavelength plate to be obtained is excellent in initial characteristics and has an influence on the use environment and the production environment. Two lasers that are difficult to receive, have long-term reliability, and have different wavelengths It is the most suitable optical information recording and reproducing apparatus for wave plate corresponding to the light.
Re (λ) / λ ... Formula (a)
[In the formula (a), λ is the wavelength (nm) of the laser beam, and Re (λ) is the retardation value (nm) of the laser beam transmitted through the wave plate. ]
Here, in the above formula (a), X = 1 and Y = 0 are preferable.
In the present invention, when a plurality of retardation films made of a cyclic olefin-based resin film are laminated to form a wave plate, the effects of the use environment and the production environment are affected by laminating each optical axis in parallel. It is possible to obtain a wave plate that is not easily affected by long-term reliability.
In addition, long-term reliability is particularly improved by adhesively fixing a retardation film made of a cyclic olefin resin film to a transparent support.

The wave plate obtained by the production method of the present invention uses a cyclic olefin resin film having high heat resistance, low hygroscopicity, high adhesion with various materials, and a stable retardation value. It is a high-performance wave plate, and when the wave plate of the present invention is used, a high-performance optical information recording / reproducing apparatus can be manufactured over a long period of time. An optical information recording / reproducing apparatus using the wave plate of the present invention is As described above, with respect to audio and image recording, it can be applied to any of a read-only recording medium, a write-once recording medium, and a rewritable recording medium,
Recording devices such as CD-ROM, CD-R, rewritable DVD and OA equipment using them, sound reproducing devices such as CD, image reproducing devices such as DVD and AV equipment using them, CD, DVD, etc. It can be used for a game machine using the.

Although the cyclic olefin resin film is used for the wave plate of the present invention, examples of the cyclic olefin resin include the following (co) polymers.

(1) A ring-opening polymer of a specific monomer represented by the following general formula (1).

(2) A ring-opening copolymer of a specific monomer represented by the following general formula (1) and a copolymerizable monomer.

(3) A hydrogenated (co) polymer of the ring-opening (co) polymer of (1) or (2) above.

(4) A (co) polymer obtained by cyclizing the ring-opening (co) polymer of (1) or (2) above by a Friedel-Craft reaction and then hydrogenating it.

(5) A saturated copolymer of a specific monomer represented by the following general formula (1) and an unsaturated double bond-containing compound.

(6) Addition type (co) of one or more monomers selected from a specific monomer represented by the following general formula (1), a vinyl cyclic hydrocarbon monomer and a cyclopentadiene monomer Polymers and their hydrogenated (co) polymers.

^Wherein, R 1 to R ⁴
Are each a hydrogen atom, a halogen atom, a hydrocarbon group having 1 to 30 carbon atoms, or other monovalent organic group, which may be the same or different. R ¹ and R ² or R ³
And R ⁴ may be combined to form a divalent hydrocarbon group, or R ¹ or R ² and R ³ or R ⁴ may be bonded to each other to form a monocyclic or polycyclic structure. Good. m is 0 or a positive integer, and p is 0 or a positive integer. ]

<Specific monomer>
Specific examples of the specific monomer include the following compounds, but the present invention is not limited to these specific examples.
Bicyclo [2.2.1] hept-2-ene,
Tricyclo [5.2.1.0 ^2,6 ] -8-decene,
Tricyclo [4.4.0.1 ^2,5 ] -3-undecene,
Tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
Pentacyclo [6.5.1.1 ^3,6 . 0 ^2,7 . 0 ^9,13 ] -4-pentadecene,
5-methylbicyclo [2.2.1] hept-2-ene,
5-ethylbicyclo [2.2.1] hept-2-ene,
5-methoxycarbonylbicyclo [2.2.1] hept-2-ene,
5-methyl-5-methoxycarbonylbicyclo [2.2.1] hept-2-ene,
5-cyanobicyclo [2.2.1] hept-2-ene,
8 methoxycarbonyltetracyclo [4.4.0.1 ^{2, 5.} 1 ^7,10 ] -3-dodecene,
8-ethoxycarbonyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8-n-propoxycarbonyltetracyclo [4.4.0.1 ^2,5
. 1 ^7,10 ] -3-dodecene,
8-Isopropoxycarbonyltetracyclo [4.4.0.1 ^2,5
. 1 ^7,10 ] -3-dodecene,
8-n-butoxycarbonyltetracyclo [4.4.0.1 ^2,5
. 1 ^7,10 ] -3-dodecene,
8-methyl-8-methoxycarbonyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8-methyl-8-ethoxycarbonyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8-methyl-8-n-propoxycarbonyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8-methyl-8-isopropoxycarbonyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8-methyl-8-n-butoxycarbonyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
5-ethylidenebicyclo [2.2.1] hept-2-ene,
8-ethylidenetetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
5-phenylbicyclo [2.2.1] hept-2-ene,
8-phenyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
5-fluorobicyclo [2.2.1] hept-2-ene,
5-fluoromethylbicyclo [2.2.1] hept-2-ene,
5-trifluoromethylbicyclo [2.2.1] hept-2-ene,
5-pentafluoroethylbicyclo [2.2.1] hept-2-ene,
5,5-difluorobicyclo [2.2.1] hept-2-ene,
5,6-difluorobicyclo [2.2.1] hept-2-ene,
5,5-bis (trifluoromethyl) bicyclo [2.2.1] hept-2-ene,
5,6-bis (trifluoromethyl) bicyclo [2.2.1] hept-2-ene,
5-methyl-5-trifluoromethylbicyclo [2.2.1] hept-2-ene,
5,5,6-trifluorobicyclo [2.2.1] hept-2-ene,
5,5,6-tris (fluoromethyl) bicyclo [2.2.1] hept-2-ene,
5,5,6,6-tetrafluorobicyclo [2.2.1] hept-2-ene,
5,5,6,6-tetrakis (trifluoromethyl) bicyclo [2.2.1] hept-2-ene,
5,5-difluoro-6,6-bis (trifluoromethyl) bicyclo [2.2.1] hept-2-ene,
5,6-difluoro-5,6-bis (trifluoromethyl) bicyclo [2.2.1] hept-2-ene,
5,5,6-trifluoro-5-trifluoromethylbicyclo [2.2.1] hept-2-ene,
5-fluoro-5-pentafluoroethyl-6,6-bis (trifluoromethyl) bicyclo [2.2.1] hept-2-ene,
5,6-difluoro-5-heptafluoro-iso-propyl-6-trifluoromethylbicyclo [2.2.1] hept-2-ene,
5-chloro-5,6,6-trifluorobicyclo [2.2.1] hept-2-ene,
5,6-dichloro-5,6-bis (trifluoromethyl) bicyclo [2.2.1] hept-2-ene,
5,5,6-trifluoro-6-trifluoromethoxybicyclo [2.2.1] hept-2-ene,
5,5,6-trifluoro-6-heptafluoropropoxybicyclo [2.2.1] hept-2-ene,
8-fluorotetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8-fluoromethyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8-difluoromethyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8-trifluoromethyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8-Pentafluoroethyltetracyclo [4.4.0.1 ^2,5
. 1 ^7,10 ] -3-dodecene,
8,8-difluorotetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8,9-difluorotetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8,8-bis (trifluoromethyl) tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8,9-bis (trifluoromethyl) tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8-methyl-8-trifluoromethyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8,8,9-trifluorotetracyclo [4.4.0.1 ^2,5
. 1 ^7,10 ] -3-dodecene,
8,8,9-tris (trifluoromethyl) tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8,8,9,9-tetrafluorotetracyclo [4.4.0.1 ^2,5
. 1 ^7,10 ] -3-dodecene,
8,8,9,9-tetrakis (trifluoromethyl) tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8,8-difluoro-9,9-bis (trifluoromethyl) tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8,9-difluoro-8,9-bis (trifluoromethyl) tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8,8,9-trifluoro-9-trifluoromethyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8,8,9-trifluoro-9-trifluoromethoxytetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8,8,9-trifluoro-9-pentafluoropropoxytetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8-fluoro-8-pentafluoroethyl-9,9-bis (trifluoromethyl) tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8,9-difluoro-8-heptafluoroiso-propyl-9-trifluoromethyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8-chloro-8,9,9-trifluorotetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8,9-dichloro-8,9-bis (trifluoromethyl) tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8- (2,2,2-trifluoroethoxycarbonyl) tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8-methyl-8- (2,2,2-trifluoroethoxycarbonyl) tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene.
These can be used alone or in combination of two or more.

Among the specific monomers, in the general formula (1), R ¹ and R ³ are each a hydrogen atom or a hydrocarbon group having 1 to 10, more preferably 1 to 4, particularly preferably 1 to 2 carbon atoms. And R ²
And R ⁴ is a hydrogen atom or a monovalent organic group, at least one of R ² and R ⁴ represents a polar group having a polarity other than a hydrogen atom and a hydrocarbon group, m is an integer of 0 to 3, p is an integer of 0 to 3, more preferably m + p = 0 to 4, more preferably 0 to 2, particularly preferably m = 1 and p = 0. The specific monomer in which m = 1 and p = 0 is preferable in that the cyclic olefin resin obtained has a high glass transition temperature and excellent mechanical strength.
Examples of the polar group of the specific monomer include a carboxyl group, a hydroxyl group, an alkoxycarbonyl group, an allyloxycarbonyl group, an amino group, an amide group, and a cyano group. These polar groups are connected via a linking group such as a methylene group. May be combined. In addition, a hydrocarbon group in which a divalent organic group having a polarity such as a carbonyl group, an ether group, a silyl ether group, a thioether group, or an imino group is bonded as a linking group can also be exemplified. Among these, a carboxyl group, a hydroxyl group, an alkoxycarbonyl group or an allyloxycarbonyl group is preferable, and an alkoxycarbonyl group or an allyloxycarbonyl group is particularly preferable.

Furthermore, the monomer in which at least one of R ² and R ⁴ is a polar group represented by the formula — (CH ₂ ) _n COOR is a material in which the obtained cyclic olefin-based resin has a high glass transition temperature, a low hygroscopic property, and various materials. It is preferable at the point from which it has the outstanding adhesiveness. In the formula relating to the specific polar group, R is a hydrocarbon group having 1 to 12 carbon atoms, more preferably 1 to 4, particularly preferably 1 to 2, and preferably an alkyl group. In addition, n is usually 0 to 5, but the smaller the value of n, the higher the glass transition temperature of the resulting cyclic olefin resin, which is preferable, and the specific monomer having n of 0 is It is preferable in that the synthesis is easy.

In the general formula (1), R ¹ or R ³ is preferably an alkyl group, preferably an alkyl group having 1 to 4 carbon atoms, more preferably an alkyl group having 1 to 2 carbon atoms, particularly preferably a methyl group. In particular, the fact that this alkyl group is bonded to the same carbon atom as that to which the specific polar group represented by the formula — (CH ₂ ) _n COOR is bonded is that of the obtained cyclic olefin-based resin. It is preferable at the point which can make hygroscopicity low.

Among the specific examples of the specific monomer, the heat resistance surface of the obtained ring-opening polymer and the change in phase difference before and after bonding when a plurality of sheets are bonded when used as the wave plate of the present invention. terms to be minimized, 8-methyl-8-methoxycarbonyltetracyclo [4.4.0.1 ^2,5 1 ^7,10] -3- dodecene is most preferable.

<Copolymerizable monomer>
Specific examples of the copolymerizable monomer include cycloolefins such as cyclobutene, cyclopentene, cycloheptene, cyclooctene, and dicyclopentadiene. The number of carbon atoms of the cycloolefin is preferably 4-20, and more preferably 5-12. These can be used alone or in combination of two or more.
A preferred use range of the specific monomer / copolymerizable monomer is 100/0 to 50/50, more preferably 100/0 to 60/40, in weight ratio.

<Ring-opening polymerization catalyst>
In the present invention, (1) a ring-opening polymer of a specific monomer, and (2) a ring-opening polymerization reaction for obtaining a ring-opening copolymer of a specific monomer and a copolymerizable monomer are metathesis It is carried out in the presence of a catalyst.
This metathesis catalyst comprises (a) at least one selected from W, Mo and Re compounds, (b) Deming periodic table group IA elements (for example, Li, Na, K, etc.), IIA group elements (for example, , Mg, Ca, etc.), Group IIB elements (eg, Zn, Cd, Hg, etc.), Group IIIA elements (eg, B, Al, etc.), Group IVA elements (eg, Si, Sn, Pb, etc.), or Group IVB A catalyst comprising a combination of at least one element selected from compounds having elements (for example, Ti, Zr, etc.) and having at least one element-carbon bond or the element-hydrogen bond. In this case, in order to increase the activity of the catalyst, an additive (c) described later may be added.

Representative examples of W, Mo or Re compounds suitable as the component (a) include WCl ₆ and MoCl _6.
And compounds such as ReOCl _{3 described in} JP-A No. 1-132626, page 8, lower left column, line 6 to page 8, upper right column, line 17.
(B) Specific examples of the _{component, n-C 4 H 9 Li} , (C 2 H 5) 3
Al, (C ₂ H ₅ ) ₂ AlCl, (C ₂ H ₅ ) _1.5 AlCl _1.5 , (C ₂ H ₅ ) AlCl ₂ , methylalumoxane, LiH, etc. JP-A-1-132626, page 8 The compounds described in the upper right column, line 18 to page 8, lower right column, line 3 can be mentioned.
As typical examples of the component (c) which is an additive, alcohols, aldehydes, ketones, amines and the like can be suitably used, but further, JP-A-1-132626, page 8, lower right column, The compounds shown in line 16 to page 9, upper left column, line 17 can be used.

The amount of the metathesis catalyst used is a range in which “(a) component: specific monomer” is usually 1: 500 to 1: 50,000 in terms of the molar ratio of the component (a) to the specific monomer. The range is preferably 1: 1,000 to 1: 10,000.
The ratio of the component (a) to the component (b) is such that (a) :( b) is 1: 1 to 1:50, preferably 1: 2 to 1:30 in terms of metal atomic ratio.
The ratio of the component (a) to the component (c) is such that the molar ratio (c) :( a) is in the range of 0.005: 1 to 15: 1, preferably 0.05: 1 to 7: 1. The

<Solvent for polymerization reaction>
Examples of the solvent used in the ring-opening polymerization reaction (solvent constituting the molecular weight modifier solution, solvent for the specific monomer and / or metathesis catalyst) include alkanes such as pentane, hexane, heptane, octane, nonane, decane, Cycloalkanes such as cyclohexane, cycloheptane, cyclooctane, decalin, norbornane, aromatic hydrocarbons such as benzene, toluene, xylene, ethylbenzene, cumene, chlorobutane, bromohexane, methylene chloride, dichloroethane, hexamethylene dibromide, chlorobenzene, Compounds such as halogenated alkanes and aryl halides such as chloroform and tetrachloroethylene, saturated carbohydrates such as ethyl acetate, n-butyl acetate, iso-butyl acetate, methyl propionate, and dimethoxyethane Esters, dibutyl ether, tetrahydrofuran, and the like can be illustrated ethers such as dimethoxyethane, it can be used singly or in combination. Of these, aromatic hydrocarbons are preferred.
As the amount of the solvent used, “solvent: specific monomer (weight ratio)” is usually in an amount of 1: 1 to 10: 1, preferably in an amount of 1: 1 to 5: 1. The

<Molecular weight regulator>
The molecular weight of the resulting ring-opening (co) polymer can be adjusted by the polymerization temperature, the type of catalyst, and the type of solvent. In the present invention, the molecular weight is adjusted by allowing the molecular weight regulator to coexist in the reaction system. To do.
Here, suitable molecular weight regulators include, for example, α-olefins such as ethylene, propene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, and the like. Styrene can be mentioned, and among these, 1-butene and 1-hexene are particularly preferable.
These molecular weight regulators can be used alone or in admixture of two or more.
The amount of the molecular weight regulator used is 0.005 to 0.6 mol, preferably 0.02 to 0.5 mol, per 1 mol of the specific monomer subjected to the ring-opening polymerization reaction.

(2) In order to obtain a ring-opening copolymer, a specific monomer and a copolymerizable monomer may be subjected to ring-opening copolymerization in the ring-opening polymerization step, and further, polybutadiene, polyisoprene, etc. In the presence of unsaturated hydrocarbon polymers such as conjugated diene compounds, styrene-butadiene copolymers, ethylene-nonconjugated diene copolymers, polynorbornene and the like containing two or more carbon-carbon double bonds in the main chain. The specific monomer may be subjected to ring-opening polymerization.

Although the ring-opening (co) polymer obtained as described above can be used as it is, (3) the hydrogenated (co) polymer obtained by further hydrogenation is a resin having high impact resistance. It is useful as a raw material.
<Hydrogenation catalyst>
In the hydrogenation reaction, a hydrogenation catalyst is added to a usual method, that is, a solution of a ring-opening polymer, and hydrogen gas at normal pressure to 300 atm, preferably 3 to 200 atm, is added thereto at 0 to 200 ° C., preferably 20 It is carried out by operating at ~ 180 ° C.
As a hydrogenation catalyst, what is used for the hydrogenation reaction of a normal olefinic compound can be used. Examples of the hydrogenation catalyst include a heterogeneous catalyst and a homogeneous catalyst.

  Examples of the heterogeneous catalyst include a solid catalyst in which a noble metal catalyst material such as palladium, platinum, nickel, rhodium, and ruthenium is supported on a carrier such as carbon, silica, alumina, and titania. In addition, homogeneous catalysts include nickel naphthenate / triethylaluminum, nickel acetylacetonate / triethylaluminum, cobalt octenoate / n-butyllithium, titanocene dichloride / diethylaluminum monochloride, rhodium acetate, chlorotris (triphenylphosphine) rhodium. Dichlorotris (triphenylphosphine) ruthenium, chlorohydrocarbonyltris (triphenylphosphine) ruthenium, dichlorocarbonyltris (triphenylphosphine) ruthenium, and the like. The form of the catalyst may be powder or granular.

These hydrogenation catalysts are used in such a ratio that the ring-opening (co) polymer: hydrogenation catalyst (weight ratio) is 1: 1 × 10 ⁻⁶ to 1: 2.
As described above, the hydrogenated (co) polymer obtained by hydrogenation has excellent thermal stability, and its characteristics deteriorate due to heating during molding and use as a product. There is no. Here, the hydrogenation rate is usually 50% or more, preferably 70% or more, and more preferably 90% or more.

  The ring-opening (co) polymer obtained as described above contains known antioxidants such as 2,6-di-t-butyl-4-methylphenol, 2,2'-dioxy-3,3. '-Di-t-butyl-5,5'-dimethyldiphenylmethane, tetrakis [methylene-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate] methane; UV absorbers such as 2,4 -It can be stabilized by adding dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone or the like. Further, additives such as a lubricant can be added for the purpose of improving processability.

The hydrogenation rate of the hydrogenated (co) polymer is 50% or more, preferably 90% or more, more preferably 98% or more, most preferably 99% or more, as measured by 500 MHz and ¹ H-NMR. is there. The higher the hydrogenation rate, the better the stability to heat and light, and when used as the wave plate of the present invention, stable characteristics can be obtained over a long period of time.
The hydrogenated (co) polymer used as the cyclic olefin resin of the present invention preferably has a gel content contained in the hydrogenated (co) polymer of 5% by weight or less. It is particularly preferable that the amount is not more than% by weight.

In addition, as the cyclic olefin-based resin of the present invention, (4) a (co) polymer obtained by cyclizing the ring-opened (co) polymer of the above (1) or (2) by a Friedel-Craft reaction and then hydrogenating it. Can be used.
<Cyclization by Friedel-Craft reaction>
The method for cyclizing the ring-opened (co) polymer of (1) or (2) by Friedel-Craft reaction is not particularly limited, but the acidic compound described in JP-A-50-154399 is used. Any known method can be employed. Specifically, Lewis acids such as AlCl ₃ , BF ₃ , FeCl ₃ , Al ₂ O ₃ , HCl, CH ₃ ClCOOH, zeolite, activated clay, and Bronsted acid are used as the acidic compound.
The cyclized ring-opening (co) polymer can be hydrogenated in the same manner as the ring-opening (co) polymer (1) or (2).

Furthermore, as the cyclic olefin resin of the present invention, (5) a saturated copolymer of the specific monomer and an unsaturated double bond-containing compound can also be used.
<Unsaturated double bond-containing compound>
As an unsaturated double bond containing compound, ethylene, propylene, butene etc., Preferably it is C2-C12, More preferably, C2-C8 olefin type compound can be mentioned.
The preferred use range of the specific monomer / unsaturated double bond-containing compound is 90/10 to 40/60, more preferably 85/15 to 50/50, in weight ratio.

In the present invention, in order to obtain a saturated copolymer of (5) a specific monomer and an unsaturated double bond-containing compound, a usual addition polymerization method can be used.
<Addition polymerization catalyst>
As the catalyst for synthesizing the (5) saturated copolymer, at least one selected from a titanium compound, a zirconium compound and a vanadium compound and an organoaluminum compound as a promoter are used.
Here, examples of the titanium compound include titanium tetrachloride and titanium trichloride, and examples of the zirconium compound include bis (cyclopentadienyl) zirconium chloride and bis (cyclopentadienyl) zirconium dichloride.

Moreover, as the vanadium compound, the general formula VO _(OR) a _{X b} or V _(OR) c _{X d,}
[Wherein R is a hydrocarbon group, X is a halogen atom, and 0 ≦ a ≦ 3, 0 ≦ b ≦ 3, 2 ≦ (a + b) ≦ 3, 0 ≦ c ≦ 4, 0 ≦ d ≦ 4, 3, ≦ (c + d) ≦ 4. ]
Or an electron-donating adduct of these compounds.
Examples of the electron donor include alcohols, phenols, ketones, aldehydes, carboxylic acids, esters of organic acids or inorganic acids, ethers, acid amides, acid anhydrides, oxygen-containing electron donors such as alkoxysilanes, ammonia, amines, Examples thereof include nitrogen-containing electron donors such as nitrile and isocyanate.

Furthermore, as the organoaluminum compound as the promoter, at least one selected from those having at least one aluminum-carbon bond or aluminum-hydrogen bond is used.
In the above, for example, when the vanadium compound is used, the ratio of the vanadium compound to the organoaluminum compound is such that the ratio of aluminum atom to vanadium atom (Al / V) is 2 or more, preferably 2 to 50, particularly preferably 3 to 20. Range.

  As the solvent for the polymerization reaction used for the addition polymerization, the same solvent as that used for the ring-opening polymerization reaction can be used. Moreover, adjustment of the molecular weight of the (5) saturated copolymer obtained is normally performed using hydrogen.

Furthermore, as the cyclic olefin resin of the present invention, (6) an addition type of one or more monomers selected from the above specific monomer and a vinyl cyclic hydrocarbon monomer or a cyclopentadiene monomer Copolymers and their hydrogenated copolymers can also be used.
<Vinyl cyclic hydrocarbon monomer>
Examples of the vinyl cyclic hydrocarbon monomer include vinylcyclopentene monomers such as 4-vinylcyclopentene and 2-methyl-4-isopropenylcyclopentene, 4-vinylcyclopentane, and 4-isopropenylcyclopentane. Vinylated 5-membered hydrocarbon monomers such as vinylcyclopentane monomers, 4-vinylcyclohexene, 4-isopropenylcyclohexene, 1-methyl-4-isopropenylcyclohexene, 2-methyl-4-vinylcyclohexene Vinylcyclohexene monomers such as 2-methyl-4-isopropenylcyclohexene, vinylcyclohexane monomers such as 4-vinylcyclohexane and 2-methyl-4-isopropenylcyclohexane, styrene, α-methylstyrene, 2 -Methylstyrene, 3- Styrenic monomers such as styrene styrene, 4-methylstyrene, 1-vinylnaphthalene, 2-vinylnaphthalene, 4-phenylstyrene, p-methoxystyrene, d-terpene, 1-terpene, diterpene, d-limonene, 1- Terpene monomers such as limonene and dipentene, vinylcycloheptene monomers such as 4-vinylcycloheptene and 4-isopropenylcycloheptene, 4-vinylcycloheptane, 4-isopropenylcycloheptane, etc. And vinyl cycloheptane monomers. Styrene and α-methylstyrene are preferable. These can be used alone or in combination of two or more.

<Cyclopentadiene monomer>
Examples of the cyclopentadiene monomer used as the monomer of the addition copolymer (6) of the present invention include, for example, cyclopentadiene, 1-methylcyclopentadiene, 2-methylcyclopentadiene, 2-ethylcyclopentadiene, Examples include 5-methylcyclopentadiene and 5,5-methylcyclopentadiene. Cyclopentadiene is preferred. These can be used alone or in combination of two or more.

The addition type (co) polymer of at least one monomer selected from the above specific monomer, vinyl cyclic hydrocarbon monomer and cyclopentadiene monomer is the above (5) specific monomer. It can be obtained by the same addition polymerization method as the saturated copolymer of the unsaturated double bond-containing compound.
The hydrogenated (co) polymer of the addition type (co) polymer can be obtained by the same hydrogenation method as the hydrogenated (co) polymer of the above (3) ring-opening (co) polymer. .

The preferable molecular weight of the cyclic olefin resin used in the present invention is 0.2 to 5 dl / g, more preferably 0.3 to 3 dl / g, particularly preferably 0.4 to 1.5 dl in terms of intrinsic viscosity [η] _inh. The polystyrene-reduced number average molecular weight (Mn) measured by gel permeation chromatography (GPC) is 8,000 to 100,000, more preferably 10,000 to 80,000, and particularly preferably 12, The weight average molecular weight (Mw) is 20,000 to 300,000, more preferably 30,000 to 250,000, particularly preferably 40,000 to 200,000. It is.
Inherent viscosity [η] _inh , number average molecular weight and weight average molecular weight are within the above ranges, so that the processability, heat resistance, water resistance, chemical resistance, mechanical properties of the cyclic olefin resin and the wavelength of the present invention The balance with the stability of the phase difference when used as a plate is good.

  The glass transition temperature (Tg) of the cyclic olefin resin used in the present invention is preferably 110 to 350 ° C, more preferably 115 to 250 ° C, and particularly preferably 120 to 200 ° C. When Tg is less than 110 ° C., the change in optical properties of the obtained cyclic polyolefin resin film is undesirably increased due to heat from the laser light source and its adjacent parts. On the other hand, when Tg exceeds 350 ° C., there is a high possibility that the resin is thermally deteriorated when heated and processed to the vicinity of Tg such as stretching.

The saturated water absorption rate at 23 ° C. of the cyclic olefin-based resin used in the present invention is preferably 0.05 to 2% by weight, more preferably 0.1 to 1% by weight. When the saturated water absorption is within this range, the phase difference is uniform, the adhesiveness between the obtained cyclic olefin resin film and the glass substrate is excellent, peeling does not occur during use, and oxidation is prevented. It is also excellent in compatibility with agents and can be added in a large amount. When the saturated water absorption is less than 0.05%, the adhesion to the glass substrate or the transparent support becomes poor, and peeling tends to occur. On the other hand, when it exceeds 2% by weight, the cyclic olefin-based resin film is formed. Dimensional change is likely to occur due to water absorption.
In addition, said saturated water absorption is a value obtained by immersing in 23 degreeC water for 1 week according to ASTMD570, and measuring an increase weight.

The cyclic olefin resin used in the present invention has a photoelastic coefficient (C _P ) of 0 to 100 (× 10 ⁻¹² Pa ⁻¹ ) and a stress optical coefficient (C _R ) of 1500 to 4,000. Those satisfying (× 10 ⁻¹² Pa ⁻¹ ) are preferably used.
Here, the photoelastic coefficient (C _P ) and the stress optical coefficient (C _R ) are various documents (Polymer Journal, Vol. 27, No, 9
pp 943-950 (1995), Journal of the Japanese Society of Rheology, Vol.19, No.2, pp93-97 (1991), Photoelastic Experimental Method, Nikkan Kogyo Shimbun, 7th edition of 1975) It is a well-known fact that the former represents the degree of occurrence of phase difference due to stress in the glassy state of the polymer, while the latter represents the degree of occurrence of phase difference due to stress in the flow state.
When the photoelastic coefficient (C _P ) is large, it becomes easy to generate a phase difference sensitively in an external factor or a stress generated from a strain generated from its own frozen strain when the polymer is used in a glass state. For example, as in the present invention, an unnecessary phase difference is generated due to a residual strain at the time of lamination when laminated and a minute stress generated by material shrinkage due to a temperature change or a humidity change. Means easy to do. Therefore, it is better that the photoelastic coefficient (C _P ) is as small as possible.
On the other hand, a large stress optical coefficient (C _R ) means that a desired phase difference can be obtained with a small stretch ratio when a cyclic olefin resin film is imparted with a retardation, or a large phase difference can be obtained. There is a great merit that it is easy to obtain a film that can be applied, and that when the same retardation is desired, the film can be thinned as compared with a film having a small stress optical coefficient (C _R ).
From the above viewpoint, the photoelastic coefficient (C _P ) is preferably 0 to 100 (× 10 ⁻¹² Pa ⁻¹ ), more preferably 0 to 80 (× 10 ⁻¹² Pa ⁻¹ ), and particularly preferably 0. To 50 (× 10 ⁻¹² Pa ⁻¹ ), more preferably 0 to 30 (× 10 ⁻¹² Pa ⁻¹ ), and most preferably 0 to 20 (× 10 ⁻¹² Pa ⁻¹ ). When the photoelastic coefficient (C _P ) exceeds 100 (× 10 ⁻¹² Pa ⁻¹ ), in the laminated wave plate used in the present invention, the stress generated during bonding and the environmental change during use It is not preferable because a phase difference change caused by the above causes a deviation from the allowable error range of the optimum bonding optical axis angle, and the amount of transmitted light may decrease when used as a wave plate.

In addition, the water vapor permeability of the cyclic olefin resin used in the present invention is usually 1 to 400 g / m ² · 24 hr when a film having a thickness of 25 μm is obtained under the conditions of 40 ° C. and 90% RH, Preferably, it is 5 to 350 g / m ² · 24 hr, and more preferably 10 to 300 g / m ² · 24 hr. By setting the water vapor transmission rate within this range, the moisture content of the pressure-sensitive adhesive and adhesive used for bonding the transparent support and the retardation film, and changes in characteristics due to the humidity of the environment in which the wavelength plate is used are reduced and avoided. It is preferable because it can be performed.

  The cyclic olefin-based resin used in the present invention includes (1), (2) ring-opening (co) polymer, (3), (4) hydrogenated (co) polymer, and (5) saturated. It is composed of a copolymer, or (6) an addition type (co) polymer and its hydrogenated (co) polymer, and it is further stabilized by adding a known antioxidant, ultraviolet absorber, etc. be able to. Moreover, in order to improve workability, the additive used in conventional resin processings, such as a lubricant, can also be added.

The cyclic olefin resin film used for the wave plate of the present invention can be obtained by forming the above cyclic olefin resin into a film or sheet by a melt molding method or a solution casting method (solvent casting method). Of these, the solvent casting method is preferred from the viewpoint of good film thickness uniformity and surface smoothness.
The method for obtaining the cyclic olefin-based resin film by the solvent casting method is not particularly limited, and a known method may be applied. For example, the cyclic olefin-based resin of the present invention is dissolved or dispersed in a solvent to obtain an appropriate amount. And a method of pouring or coating on a suitable carrier, drying it, and then peeling it from the carrier.
Below, although various conditions of the method of obtaining a cyclic olefin resin film by a solvent cast method are shown, this invention is not limited to these conditions.

  When the cyclic olefin-based resin is dissolved or dispersed in a solvent, the concentration of the resin is usually 0.1 to 90% by weight, preferably 1 to 50% by weight, and more preferably 10 to 35% by weight. When the concentration of the resin is less than the above, it becomes difficult to secure the thickness of the film, and problems such as difficulty in obtaining the surface smoothness of the film due to foaming due to solvent evaporation and the like occur. On the other hand, a concentration exceeding the above is not preferable because the solution viscosity becomes too high and the thickness and surface of the cyclic olefin resin film obtained are difficult to be uniform.

  The viscosity of the solution at room temperature is usually 1 to 1,000,000 mPa · s, preferably 10 to 100,000 mPa · s, more preferably 100 to 50,000 mPa · s, and particularly preferably 1,000. ˜40,000 mPa · s.

  Solvents used include aromatic solvents such as benzene, toluene, xylene, cellosolve solvents such as methyl cellosolve, ethyl cellosolve, 1-methoxy-2-propanol, diacetone alcohol, acetone, cyclohexanone, methyl ethyl ketone, 4-methyl. Ketone solvents such as 2-pentanone, ester solvents such as methyl lactate and ethyl lactate, cycloolefin solvents such as cyclohexanone, ethylcyclohexanone and 1,2-dimethylcyclohexane, 2,2,3,3-tetrafluoro- Examples thereof include halogen-containing solvents such as 1-propanol, methylene chloride and chloroform, ether solvents such as tetrahydrofuran and dioxane, and alcohol solvents such as 1-pentanol and 1-butanol.

Also, other than the above, SP value (solubility parameter) is usually 10 to 30 (MPa ^1/2), preferably 10 to 25 (MPa ^1/2), more preferably 15-25 (MPa ^1/2) Particularly preferably, when a solvent in the range of 15 to 20 (MPa ^1/2 ) is used, a cyclic olefin resin film having good surface uniformity and optical properties can be obtained.

The said solvent can be used individually or in mixture of multiple. In that case, it is preferable that the range of the SP value when the mixed system is used is within the above range. At this time, the value of the SP value in the mixed system can be predicted by a weight ratio. For example, in the case of mixing two kinds, if the respective weight fractions are W1 and W2, and the SP values are SP1 and SP2, the SP of the mixed system. The value is the following formula:
SP value = W1 · SP1 + W2 · SP2
It can obtain | require as a value calculated by.

  As a method for producing a cyclic olefin-based resin film by a solvent casting method, the above solution can be obtained by using a die or a coater, a metal drum, a steel belt, a polyester film such as polyethylene terephthalate (PET) or polyethylene naphthalate (PEN), Teflon. In general, a method of coating on a substrate such as a belt, and then drying the solvent to peel the film from the substrate can be mentioned. Moreover, it can also manufacture by apply | coating a solution to a base material by spraying, brushing, roll spin coating, dipping, etc., drying a solvent after that, and peeling a film from a base material. In addition, you may control thickness, surface smoothness, etc. by apply | coating repeatedly.

  The drying process of the solvent casting method is not particularly limited and can be carried out by a generally used method such as a method of passing through a drying furnace through a number of rollers. If this occurs, the characteristics of the film are remarkably deteriorated. Therefore, in order to avoid this, it is preferable to set the drying step to a plurality of steps of two or more stages and to control the temperature or the air volume in each step.

  Further, the amount of residual solvent in the cyclic olefin resin film is usually 10% by weight or less, preferably 5% by weight or less, more preferably 1% by weight or less, and particularly preferably 0.5% by weight or less. Here, if the residual solvent amount exceeds 10% by weight, the dimensional change with time becomes large when actually used, which is not preferable. Further, the residual solvent is not preferable because Tg is lowered and heat resistance is also lowered.

In addition, in order to perform the extending | stretching process mentioned later suitably, it is necessary to adjust the said residual solvent amount suitably within the said range. Specifically, in order to stably and evenly express the phase difference during stretching orientation, the residual solvent amount is usually 10 to 0.1% by weight, preferably 5 to 0.1% by weight, more preferably 1 May be -0.1 wt%.
By leaving a trace amount of the solvent, stretching may be facilitated or phase difference may be easily controlled.

  The thickness of the cyclic olefin resin film of the present invention is usually 0.1 to 500 μm, preferably 0.1 to 300 μm, and more preferably 1 to 250 μm. When the thickness is less than 0.1 μm, handling becomes substantially difficult. On the other hand, when the thickness exceeds 500 μm, it is difficult to wind in a roll shape, and the wavelength plate of the present invention aiming at high transmittance of laser light is not preferable because the transmittance decreases.

  The thickness distribution of the cyclic olefin resin film of the present invention is usually within ± 20%, preferably within ± 10%, more preferably within ± 5%, particularly preferably within ± 3% with respect to the average value. The thickness variation per 1 cm is usually 10% or less, preferably 5% or less, more preferably 1% or less, and particularly preferably 0.5% or less. By carrying out such thickness control, it is possible to prevent retardation unevenness when stretched and oriented.

  As the retardation film composed of the cyclic olefin resin film used for the wave plate of the present invention, a film obtained by stretching the cyclic olefin resin film obtained by the above method is preferably used. Specifically, it can be produced by a known uniaxial stretching method or biaxial stretching method. That is, the horizontal uniaxial stretching method by the tenter method, the compression stretching method between rolls, the longitudinal uniaxial stretching method using rolls with different circumferences, the biaxial stretching method in which the transverse uniaxial and longitudinal uniaxial are combined, the stretching method by the inflation method, etc. Can be used.

In the case of the uniaxial stretching method, the stretching speed is usually 1 to 5,000% / minute, preferably 50 to 1,000% / minute, more preferably 100 to 1,000% / minute, Preferably, it is 100 to 500% / min.
In the case of the biaxial stretching method, stretching may be performed in two directions at the same time, or the stretching may be performed in a direction different from the first stretching direction after uniaxial stretching. In these cases, the intersection angle of the two stretching axes is usually in the range of 120 to 60 degrees. The stretching speed may be the same or different in each stretching direction, and is usually 1 to 5,000% / min, preferably 50 to 1,000% / min, more preferably Is from 100 to 1,000% / min, particularly preferably from 100 to 500% / min.

  The stretching temperature is not particularly limited, but is usually Tg ± 30 ° C., preferably Tg ± 10 ° C., more preferably Tg based on the glass transition temperature (Tg) of the cyclic olefin resin of the present invention. It is in the range of −5 to Tg + 10 ° C. Within the above range, it is possible to suppress the occurrence of phase difference unevenness, and it is preferable because the control of the refractive index ellipsoid becomes easy.

  The draw ratio is not particularly limited because it is determined by the desired properties, but is usually 1.01 to 10 times, preferably 1.1 to 5 times, and more preferably 1.1 to 3 times. When the draw ratio exceeds 10 times, it may be difficult to control the phase difference.

  The stretched film may be cooled as it is, but it should be allowed to stand in a temperature atmosphere of Tg-20 ° C. to Tg for at least 10 seconds, preferably 30 seconds to 60 minutes, more preferably 1 minute to 60 minutes. Is preferred. Thereby, the retardation film which consists of a stable cyclic olefin resin film with little change with time of retardation characteristics is obtained.

Moreover, the linear expansion coefficient of the cyclic olefin-based resin film of the present invention is preferably 1 × 10 ⁻⁴ (1 / ° C.) or less, more preferably 9 × 10 ⁻⁵ (1) in the temperature range of 20 ° C. to 100 ° C. / ° C.) or less, particularly preferably 8 × 10 ⁻⁵ (1 / ° C.) or less, and most preferably 7 × 10 ⁻⁵ (1 / ° C.) or less. In the case of a retardation film, the difference in linear expansion coefficient between the stretching direction and the direction perpendicular thereto is preferably 5 × 10 ⁻⁵ (1 / ° C.) or less, more preferably 3 × 10 ⁻⁵ (1 / ° C.). ) Or less, particularly preferably 1 × 10 ⁻⁵ (1 / ° C.) or less. By setting the linear expansion coefficient within the above range, when the retardation film made of the cyclic olefin resin film of the present invention is used as the wave plate of the present invention, the stress change due to the influence of temperature, humidity, etc. during use is reduced. The change of the applied phase difference is suppressed, and long-term stability can be obtained when used as the wave plate of the present invention.

The film stretched as described above is oriented with molecules by stretching and gives a phase difference to transmitted light. This phase difference is the retardation value of the film before stretching, the stretching ratio, the stretching temperature, the stretching orientation. It can be controlled by the thickness of the later film. Here, the phase difference is defined by the product (Δnd) of the refractive index difference (Δn) of birefringent light and the thickness (d).
When the film before stretching has a certain thickness, the larger the stretching ratio, the larger the absolute value of the retardation. Therefore, the retardation film having a desired retardation value can be obtained by changing the stretching ratio. Can do.

The retardation value at a light wavelength of 550 nm of the retardation film comprising the cyclic olefin resin film used in the present invention is preferably 10 to 3,000 nm, more preferably 50 to 2,000 nm, and particularly preferably 100 to 1,500 nm. Most preferably, the thickness is 130 to 1,000 nm.
When the phase difference value is out of the above range, it may be difficult to obtain a target wave plate having a specific phase difference with respect to two laser beams having different wavelengths.

Moreover, the wavelength dependence represented by the following formula (b) of the retardation of the retardation film made of the cyclic olefin resin film used in the present invention is preferably as small as possible in the wavelength range of 400 to 800 nm. The value of the following formula (b) is usually in the range of 0.8 to 1.2, preferably 0.9 to 1.1, and more preferably 0.95 to 1.05. By setting the wavelength dependence of the phase difference to such a range, it becomes easy to obtain a wave plate having a specific phase difference with respect to two laser beams having different wavelengths.
Re (λ) / Re (550) (b)
[In the formula (b), Re (λ) is a phase difference value at an arbitrary wavelength, and Re (550) is a phase difference value at a wavelength of 550 nm. ]

  In the present invention, the two laser beams having different wavelengths mean, for example, 785 nm used for CD and CD-R and 650 nm laser light for DVD. Moreover, the combination of the blue laser around 400 nm developed recently and either of the said 2 types of red laser may be sufficient.

The wave plate of the present invention exhibits a function as a so-called “¼λ plate” that performs mutual conversion between linearly polarized light and circularly polarized light with respect to the first laser light. In order to express such a function, the value of the following formula (a) is usually (0.2 to 0.3) + X, preferably (0.22 to 0.28) + X, more preferably (0. 24 to 0.26) + X (where X represents an integer multiple of 0 or 0.5).
In order to function as a “λ plate” that does not substantially contribute to the conversion of the polarization state with respect to the second laser light, it is usually (0.8 to 1.2) + Y, preferably (0.9 To 1.1) + Y, more preferably (0.95 to 1.05) + Y (wherein Y represents 0 or an integer of 1 or more).
Re (λ) / λ ... Formula (a)
[In the formula (a), λ is the wavelength (nm) of the laser beam, and Re (λ) is the retardation value (nm) of the laser beam transmitted through the wave plate. ]

The value in () of the formula (0.20 to 0.30) + X representing the value of the above formula (a) is preferably close to 0.25, a value lower than 0.20, or 0.30. If the value exceeds this value, the mutual conversion efficiency between linearly polarized light and circularly polarized light is reduced to become elliptically polarized light, which is not preferable because accuracy when used in an optical information recording / reproducing apparatus is deteriorated.
Further, the value in () of the formula (0.8 to 1.2) + Y representing the value of the above formula (a) is preferably close to 1, and a value lower than 0.8 or 1.2 A value exceeding this is not preferable because it becomes elliptically polarized light and changes the polarization state of the transmitted light, resulting in poor accuracy when used in an optical information recording / reproducing apparatus.

In the wave plate of the present invention, it is preferable that the wavelength of the first laser light is shorter than the wavelength of the second laser light, and that X = 1 and Y = 0 is practical and easy to manufacture. . Examples of the combination of the laser beams include a case where the wavelength of the first laser beam is 650 nm and the wavelength of the second laser beam is 785 nm. In this case, it can be suitably used as a wavelength plate for an optical information recording / reproducing apparatus compatible with two types of optical disks, CD or CD-R and DVD.
The wave plate of the present invention needs to have a phase difference of 780 to 845 nm with respect to the laser beam of 650 nm and a phase difference of 628 to 942 nm with respect to the laser beam of 785 nm. The request | requirement which concerns easily can be achieved by using the retardation film which consists of a cyclic olefin resin film in which the wavelength dependence of a phase difference exists in a specific range.

In the present invention, in order to obtain a desired retardation, a plurality of retardation films made of a cyclic olefin resin film may be laminated. Such a lamination may be a lamination of films, or a transparent support such as glass may be sandwiched between them, and a plurality of transparent supports to which the film is bonded may be laminated. It may be sandwiched between transparent supports such as glass. Among these, the method using a transparent support is preferable in terms of improving the durability of the obtained wave plate.
For lamination, natural rubber, synthetic rubber, vinyl acetate / vinyl chloride copolymer, silicon, polyvinyl ether, acrylic, modified polyolefin, epoxy or urethane adhesive, UV curable adhesive, etc. Known optical adhesives / adhesives such as adhesives and acrylic pressure-sensitive adhesives can be used. In the lamination, the surface of the retardation film or the transparent support may be subjected to a ground treatment such as corona treatment, plasma treatment, coupling agent treatment or anchor coat treatment.

When laminating a plurality of retardation films, they are laminated so that the optical axes (fast axis or slow axis) of the respective retardation films are parallel to each other. By laminating the optical axes in parallel, the function as a “¼λ plate” or “λ plate” can be expressed for two laser beams having different wavelengths. Thus, when the retardation film is laminated, the retardation required for one retardation film can be reduced, and the magnification during stretching can be reduced, resulting in the retardation of the retardation when used as a wave plate. The degree of variation can be reduced.
The number of layers to be laminated is not particularly limited, but it is difficult to adjust the angle of the optical axis of each retardation film to laminate when the number of layers to be laminated, and the light transmittance may be reduced. Is 2 to 10 sheets, preferably 2 to 5 sheets, and more preferably 2 to 3 sheets.
The substantially allowable deviation of the optical axis in the lamination is usually in the range of ± 15 degrees, preferably ± 10 degrees, and more preferably ± 5 degrees. By laminating in this range, the function as a “¼λ plate” or “λ plate” can be accurately expressed for two laser beams having different wavelengths.

In the present invention, an antireflection film can be laminated on one or both sides of a retardation film made of a cyclic olefin resin or a transparent support.
As a method for forming the antireflection film, for example, a fluorine-based copolymer is dissolved in an organic solvent, and the solution is cast on the above film, sheet material, retardation plate, or the like using a bar coater or the like. The method of apply | coating, heating using a press, and making it harden | cure is mentioned. The heating temperature is usually 80 to 165 ° C, preferably 100 to 150 ° C, and the heating time is usually 10 minutes to 3 hours, preferably 30 minutes to 2 hours.
The thickness of the antireflection film is usually 5 to 2,000 nm, preferably 10 to 1,000 nm, and more preferably 50 to 200 nm. When the thickness is less than 5 nm, the antireflection effect cannot be exhibited. On the other hand, when the thickness exceeds 2,000 nm, unevenness is likely to occur in the thickness of the coating film, and the appearance is deteriorated.
Further, an antireflection film can be formed by providing a coating layer of a transparent inorganic oxide such as aluminum, magnesium, or silicon by using a vapor deposition method or a sputtering method.
In the case of such an inorganic antireflection film, the thickness of the transparent inorganic oxide coating layer is ¼ of the specific light wavelength. Furthermore, it is said that the antireflection performance can be further improved by laminating such transparent inorganic oxide coating layers.

In the present invention, the durability stability as a wave plate can be improved by bonding the retardation film to the transparent support. Such a transparent support preferably has substantially no birefringence. It is not preferable that the transparent support has birefringence because it affects the properties as a wave plate. In addition, as the transparent support, an organic material and / or an inorganic material can be used, but an inorganic material is preferred, and optical properties such as substantially no birefringence and excellent transparency are provided. Glass is particularly preferred.
On the other hand, when an organic material is used, the temperature at which it can be continuously used in a state where it is formed on a support (temperature at which deformation or coloring does not occur even after exposure for 1,000 hours or more) is usually 100 ° C. or more, preferably Is 120 ° C. or higher, more preferably 150 ° C. or higher, and water vapor permeability is 40 ° C. and 90% RH, usually 20 g / m ² · 24 hr or less, preferably 10 g / m ² · 24 hr or less, Preferably, 5 g / m ² · 24 hr or less is used. When the continuous usable temperature and the water vapor transmission rate are out of the above ranges, the initial characteristics may change due to coloring or deformation when used as a wave plate for a long time, which is not preferable. Moreover, when using an organic material, in order to prevent the deformation | transformation by a heat | fever or stress more, the thickness of a support body is 0.5-5 mm normally, Preferably it is 0.5-1 mm. If the thickness is thinner than this, it may be deformed by heat or stress, or the water vapor transmission rate may be out of the above range. On the other hand, if it is too thick, it may be difficult to work and the light transmittance may be reduced. Absent.
Examples of the organic material that can be used as the transparent support include thermosetting epoxy resins, polyarylate, heat-resistant acrylic resins, polysulfones, polycarbonates, polyether sulfones, and cyclic olefin resins.

  The difference in refractive index between the transparent support and the adhesive layer is preferably within 0.20, more preferably within 0.15, particularly preferably within 0.10, and most preferably within 0.05. The difference in refractive index between the transparent support and the resin film of the present invention is preferably within 0.20, more preferably within 0.15, particularly preferably within 0.10, most preferably within 0.05. is there. By making the difference in refractive index within this range, loss due to reflection of transmitted light can be minimized, which is preferable.

  In the present invention, the shape of the transparent support is not particularly limited, and may be a flat plate shape or a shape having an optical function such as a lattice shape or a prism shape. Moreover, thickness is 0.01-5 mm normally, Preferably it is 0.05-3 mm, More preferably, it is 0.05-1 mm. When the thickness is less than 0.01 mm, the rigidity is insufficient and the handling property is inferior. On the other hand, when the thickness exceeds 5 mm, the size of the wave plate increases and it is difficult to reduce the size of the optical system device.

  The preferred in-plane aberration of the wave plate of the present invention is within 30 (mλ), more preferably within 20 (mλ), particularly preferably within 10 (mλ), and most preferably within 5 (mλ). By setting the in-plane aberration of the plate within the above range, it is preferable because an excellent S / N and an allowable jitter range are obtained. Here, λ is the wavelength of transmitted light.

The number of foreign substances in the wave plate of the present invention is preferably as small as possible, and those having an average particle size of 10 μm or more are usually 10 (pieces / mm ² ) or less, preferably 5 (pieces / mm ² ) or less. More preferably, it is 1 (pieces / mm ² ) or less. If the number of foreign matters of 10 μm or more exceeds 10 (pieces / mm ² ) in the wave plate, the noise signal increases and the S / N ratio becomes small, which is not preferable. Here, the foreign matter in the wave plate includes those that reduce the transmission of the laser light and those that greatly change the traveling direction of the laser light due to the presence of the foreign matter. Examples of the former include dust and dust, resin burns, powders of metal powders, minerals, and the like, and examples of the latter include contamination of other resins and transparent substances having different refractive indexes.

  Note that the wave plate of the present invention has been colored using a known colorant or the like in order to block or reduce the transmission of light having a wavelength other than the desired wavelength as necessary for noise reduction or the like. May be.

The wave plate of the present invention uses a cyclic olefin resin film having high heat resistance, low hygroscopicity, high adhesion with various materials, and a stable retardation value. If the wave plate of the present invention is used, a high-performance optical information recording / reproducing apparatus can be manufactured over a long period of time.
Note that the optical information recording / reproducing apparatus using the wave plate of the present invention can be applied to any of a reproduction-only recording medium, a write-once recording medium, and a rewritable recording medium for recording audio and images as described above. ,
Recording devices such as CD-ROM, CD-R, rewritable DVD and OA equipment using them, sound reproducing devices such as CD, image reproducing devices such as DVD and AV equipment using them, CD, DVD, etc. It can be used for a game machine using the.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated further more concretely, this invention is not limited at all by these Examples. In addition, unless otherwise indicated, the part and% in an Example are a weight part and weight%. The various measurements in the examples are as follows.

Intrinsic viscosity ([η] _inh )
Chloroform or cyclohexane was used as a solvent, and measurement was performed with an Ubbelohde viscometer at a polymer concentration of 0.5 g / dl at 30 ° C.
At a temperature of gel content of 25 ° C., 50 g of a hydrogenated (co) polymer was dissolved in chloroform so as to have a concentration of 1%, and this solution was previously measured for a membrane filter having a pore size of 0.5 μm [Advantech Toyo. (Corporation)], and after filtering the filtered filter, the gel content was calculated from the increase in weight.

In the case of a hydrogenated hydrogenated homopolymer, 500 MHz and ¹ H-NMR are measured, and the ratio of the absorption intensity of methyl hydrogen and olefinic hydrogen of the ester group, or each of paraffinic hydrogen and olefinic hydrogen, respectively. The hydrogenation rate was measured from the ratio of the absorption intensity. In the case of a hydrogenated copolymer, the calculation was made by comparing the ¹ H-NMR absorption of the copolymer after polymerization with that of the hydrogenated copolymer after hydrogenation.
A glass transition temperature scanning calorimeter (DSC) was measured at a heating rate of 10 ° C./min in a nitrogen atmosphere.

Film thickness Measured using a Keyence Co., Ltd., laser focus displacement meter, LT-8010.
Retardation value Oji Scientific Instruments Co., using KOBRA-21ADH, measured at a wavelength 480,550,590,630,750Nm, Cauchy portions other than the wavelength by using the retardation value at the wavelength ( Cauchy) was used for the calculation.

<Synthesis Example 1>
8-methyl-8-methoxycarbonyltetracyclo [4.4.0.1 ^2,5 . In a reaction vessel in which 250 parts of 1 ^7,10 ] -3-dodecene (specific monomer), 27 parts of 1-hexene (molecular weight regulator) and 750 parts of toluene (solvent for ring-opening polymerization reaction) were replaced with nitrogen. Charge and heat the solution to 60 ° C. Next, 0.62 parts of a toluene solution of triethylaluminum (1.5 mol / 1) as a polymerization catalyst and tungsten hexachloride modified with t-butanol and methanol (t-butanol: methanol: tungsten) were added to the solution in the reaction vessel. = 0.35 mol: 0.3 mol: 1 mol) of a toluene solution (concentration 0.05 mol / 1) 3.7 parts was added, and the system was heated and stirred at 80 ° C. for 3 hours to open the ring. Polymerization reaction was performed to obtain a ring-opening polymer solution. The polymerization conversion rate in this polymerization reaction was 97%, and the intrinsic viscosity (η _inh ) of the obtained ring-opened polymer measured in chloroform at 30 ° C. was 0.62 dl / g.
The autoclave was charged with 4,000 parts of the ring-opening polymer solution thus obtained, and 0.48 part of RuHCl (CO) [P (C ₆ H ₅ ) ₃ ] ₃ was added to the ring-opening polymer solution. Then, the hydrogenation reaction was performed by heating and stirring for 3 hours under the conditions of a hydrogen gas pressure of 100 kg / cm ² and a reaction temperature of 165 ° C.
After cooling the obtained reaction solution (hydrogenated polymer solution), the hydrogen gas was released. This reaction solution was poured into a large amount of methanol to separate and recover a coagulated product, which was dried to obtain a hydrogenated polymer (hereinafter referred to as “resin A”).
The hydrogenation rate of the resin A thus obtained was measured using ¹ H-NMR and found to be 99.9%. Moreover, it was 165 degreeC when the glass transition temperature (Tg) was measured by DSC method about the said resin. Moreover, when the number average molecular weight (Mn) and weight average molecular weight (Mw) of polystyrene conversion were measured about the said resin by GPC method (solvent: tetrahydrofuran), Mn was 42,000, Mw was 180,000, molecular weight distribution. (Mw / Mn) was 4.29. Further, the saturated water absorption rate at 23 ° C. of the resin was measured and found to be 0.3%. Moreover, it was 19 (MPa ^{/ 2} ) when SP value was measured. Further, when the intrinsic viscosity (η _inh ) of the resin was measured in chloroform at 30 ° C., 0.67 dl / g
Met. The gel content was 0.4%.

<Synthesis Example 2>
As a specific monomer, 8-methyl-8-methoxycarbonyltetracyclo [4.4.0.1 ^2,5 . 1, ¹⁰ ] -3-dodecene 225 parts and bicyclo [2.2.1] hept-2-ene 25 parts, and the addition amount of 1-hexene (molecular weight regulator) was 43 parts Obtained a hydrogenated polymer in the same manner as in Synthesis Example 1. The hydrogenation rate of the obtained hydrogenated polymer (hereinafter referred to as “resin B”) was 99.9%.

<Synthesis Example 3>
As a specific monomer, 8-methyl-8-methoxycarbonyltetracyclo [4.4.0.1 ^2,5 . Except that 215 parts of ^{17, 10} ] -3-dodecene and 35 parts of bicyclo [2.2.1] hept-2-ene were used and the addition amount of 1-hexene (molecular weight regulator) was 18 parts. Obtained a hydrogenated polymer in the same manner as in Synthesis Example 1. The hydrogenation rate of the obtained hydrogenated polymer (hereinafter referred to as “resin C”) was 99.9%.

<Film Production Example 1>
Resin A is dissolved in toluene to a concentration of 30% (solution viscosity at room temperature is 30,000 mPa · S), and surface treatment is made hydrophilic (easy adhesion) with acrylic acid using INVEX Lab Coater made by Inoue Metal Industry. The dried PET film (Toray, Lumirror U94) having a thickness of 100 μm was applied so that the film thickness after drying was 100 μm, and this was subjected to primary drying at 50 ° C. and then secondary drying at 90 ° C. A resin film A peeled from the PET film was obtained. The residual solvent amount of the obtained film was 0.5%.
The photoelastic coefficient (C _P ) and stress optical coefficient (C _R ) of this film were determined by the following method. Specifically, the photoelastic coefficient (C _P ) was calculated from a phase difference generated at the room temperature (25 ° C.) and a stress applied to the sample at that time by applying several kinds of constant loads to the strip-shaped film sample. For the stress optical coefficient (C _R ), the phase difference generated after the film sample was slowly cooled to room temperature after being stretched by several percent under several constant loads above Tg and returned to room temperature was measured. It was calculated from the applied stress. The results were C _P = 4 (× 10 ⁻¹² pa ⁻¹ ) and C _R = 1750 (× 10 ⁻¹² pa ⁻¹ ), respectively.
The characteristic values of the resin film A are shown in Table 1.

<Film Production Example 2>
Resin B was used and Resin Film B was obtained in the same manner as Film Production Example 1. The amount of residual solvent of the obtained resin film B is 0.5%, and the photoelastic coefficient (C _P ) and the stress optical coefficient (C _R ) are C _P = 6 (× 10 ⁻¹² pa ⁻¹ ), C _R = 2000 (× 10 ⁻¹² pa ⁻¹ ).
The characteristic values of the resin film B are shown in Table 1.

<Film Production Example 3>:
Resin C was used to obtain Resin Film C in the same manner as Film Production Example 1. The residual solvent amount of the obtained resin film C is 0.5%, and the photoelastic coefficient (C _P ) and the stress optical coefficient (C _R ) are C _P = 9 (× 10 ⁻¹² pa ⁻¹ ), respectively. , C _R = 2350 (× 10 ⁻¹² pa ⁻¹ ).
The characteristic values of the resin film C are shown in Table 1.

<Example 1>
The resin film A is heated in a tenter to 175 ° C., which is Tg + 10 ° C., and uniaxially stretched 3.4 times at a stretching rate of 400% / min, and this state is maintained for 1 minute in an atmosphere at 110 ° C. When cooled and further cooled to room temperature, a 55 μm-thick retardation film A-1 could be obtained. A glass plate having a thickness of 250 μm was laminated on one surface of the retardation film A-1 using an acrylic adhesive having a thickness of 10 μm to obtain a wave plate A-1. This wavelength plate A-1 was confirmed to have a phase difference of 810 nm at a wavelength of 650 nm and a phase difference of 805 nm at a wavelength of 785 nm.
Moreover, it confirmed that the number of the foreign materials of 10 micrometers or more in the wavelength plate A-1 was 10 or less with the polarizing microscope.

<Example 2>
A retardation film A-2 having a thickness of 70 μm could be obtained in the same manner except that the stretching ratio was 1.8 times in the stretching method of Example 1. Two retardation films A-2 were bonded and laminated in the same manner as in Example 1 with a configuration in which a glass plate was sandwiched between them so that their optical axes (fast axes) were parallel, and a wave plate A- 2 was obtained. This wavelength plate A-2 was confirmed to have a phase difference of 812 nm at a wavelength of 650 nm and a phase difference of 806 nm at a wavelength of 785 nm.
Moreover, it confirmed that the number of the foreign materials of 10 micrometers or more in the wavelength plate A-2 was 10 or less with the polarizing microscope.

<Example 3>
Using the resin film B, a retardation film B having a thickness of 65 μm was obtained in the same manner as in Example 1 except that the stretching condition was 2.0 times the stretching ratio and the heating temperature was 145 ° C. Further, a wave plate B was obtained in the same manner as in Example 1 by using one retardation film B. This wavelength plate B was confirmed to have a phase difference of 810 nm at a wavelength of 650 nm and a phase difference of 802 nm at a wavelength of 785 nm.
In addition, it was confirmed by a polarizing microscope that the number of foreign matters of 10 μm or more in the wave plate B was 10 or less.

<Example 4>
Using the resin film C, a retardation film C having a thickness of 70 μm was obtained in the same manner as in Example 1 except that the stretching condition was 1.8 times the stretching ratio and the heating temperature was 130 ° C. Further, a wave plate C was obtained in the same manner as in Example 1 using one retardation film C. This wave plate C was confirmed to have a phase difference of 810 nm at a wavelength of 650 nm and a phase difference of 800 nm at a wavelength of 785 nm.
Further, it was confirmed by a polarizing microscope that the number of foreign matters having a size of 10 μm or more in the wave plate C was 10 or less.

<Example 5>
As an optical information recording / reproducing device using the wavelength plate of the present invention, an optical pickup device 10 using a wavelength plate as shown in FIG. 1 is used. In the optical pickup device 10, a laser diode (LD) that is a laser light source is used. ) 20 are installed in parallel and transmit laser beams having wavelengths of 650 nm and 785 nm, respectively, and a polarizing beam splitter (PBS) 21 and the wave plate (QWP) are located in the middle of the forward path to the optical recording medium 23. 22 and the objective lens 23 are arranged. The return path of the return light reflected from the optical recording medium 24 passes through the objective lens 23 and the wavelength plate 22, is changed in the traveling direction by 90 ° by the PBS 21, and reaches the photodetector 25. Information was read and written over a long period of time (80 ° C., 90% RH atmosphere) using each of the plates A-1, A-2, B and C independently. As a result, it was found that, in addition to the good initial characteristics, even after 3000 hours, the rate of change was within 1% with respect to the initial characteristics, indicating good stability. In particular, for the wave plate A-1, the rate of change was within 0.5%, and it was found that the characteristics were very stable.

<Comparative Example 1>
A polycarbonate film was obtained in the same manner as in Film Production Example 1, except that polycarbonate A2700 manufactured by Idemitsu Petrochemical Co., Ltd. was used as a raw material and the solvent was methylene chloride. Table 1 shows the characteristic values of the obtained polycarbonate film.
Further, this film was heated in a tenter to 160 ° C., which is Tg + 5 ° C., stretched 1.4 times at a stretching rate of 400% / min, and then cooled while maintaining this state for 1 minute in an atmosphere at 110 ° C. Then, when further cooled to room temperature and taken out, a polycarbonate retardation film D having a thickness of 80 μm could be obtained.
Using one retardation film D, a wave plate D was obtained in the same manner as in Example 1. This wavelength plate D was confirmed to have a phase difference of 810 nm at a wavelength of 650 nm and a phase difference of 770 nm at a wavelength of 785 nm.

<Comparative example 2>
When the wave plate D obtained in Comparative Example 1 was used in the same manner as in Example 5 and the initial characteristics and the long-term use test were performed, the initial characteristics were slightly inferior to those of the wave plates A-1 to C. However, the rate of change with respect to the initial characteristics after 3000 hours of use was 5%, and it was found that there was a problem in the stability of characteristics.

It is a schematic block diagram of an example of the optical pick-up apparatus which can apply the wavelength plate of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Optical pick-up apparatus 21 Polarizing beam splitter 22 Wave plate 24 Optical recording medium

Claims (4)

A wave plate using a stretched and oriented film containing a cyclic olefin-based resin, wherein the value of the following formula (a) is obtained for two laser beams having different wavelengths, and (0. 2 to 0.3) + X, and (0.8 to 1.2) + Y for the second laser light (where X is 0 or an integer multiple of 0.5, and Y is A method for producing a wavelength plate for a laser optical system, which is stretched so as to be 0 or an integer of 1 or more.
Re (λ) / λ ... Formula (a)
[In the formula (a), λ is the wavelength (nm) of the laser beam, and Re (λ) is the retardation value (nm) of the laser beam transmitted through the wave plate. ]   The method of manufacturing a wavelength plate for a laser optical system according to claim 1, wherein in the formula (a), X = 1 and Y = 0. A film containing a stretched and oriented cyclic olefin-based resin is stretched to obtain a retardation film, and a plurality of obtained retardation films are formed so that each optical axis is parallel, and the following formula (a) Of the first laser beam is (0.2 to 0.3) + X, and the second laser beam is (0.8 to 1.2) + Y (where X is 0 or 0). The wavelength for laser optical system according to claim 1 or 2, wherein the wavelength is a number that is an integer multiple of .5, and Y is an integer of 0 or 1 or more. A manufacturing method of a board.
Re (λ) / λ ... Formula (a)
[In the formula (a), λ is the wavelength (nm) of the laser beam, and Re (λ) is the retardation value (nm) of the laser beam transmitted through the wave plate. ]   The method for producing a wavelength plate for a laser optical system according to any one of claims 1 to 3, wherein a film containing the cyclic olefin-based resin that has been stretched and oriented is bonded and fixed to a transparent support.

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