JP2010096942A - Optical recording compound, optical recording composition, and holographic recording medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical recording compound suitable for high-sensitive and large-capacity digital volume holography, an optical recording composition containing the compound, and a holographic recording medium allowing ultra-high density optical recording using the composition. <P>SOLUTION: The optical recording compound is a vinylthiirane compound expressed by general formula (I), wherein R<SP>1</SP>, R<SP>2</SP>, R<SP>3</SP>and R<SP>4</SP>represent independently hydrogen atom or an alkyl, respectively. The holographic recording medium has a recording layer containing the compound. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a vinyl thiirane compound used for optical recording and an optical recording composition containing the compound. More specifically, the optical recording compound suitable as a recording compound for a holographic recording medium, particularly a volume holographic recording medium having a relatively thick recording layer, and the holographic recording medium, particularly volume holographic recording, containing the compound. The present invention relates to an optical recording composition suitable for production of a medium. Furthermore, the present invention relates to a holographic recording medium having a recording layer containing the optical recording compound.

  Conventionally, development of a holographic optical recording medium using a holographic principle has been advanced. Information is recorded on a holographic optical recording medium by superimposing information light containing image information and reference light in a recording layer made of a photosensitive composition, and writing interference fringes formed at that time on the recording layer. Done. On the other hand, when information is reproduced, reference light is incident on the recording layer on which information is recorded at a predetermined angle, whereby light diffraction of the reference light due to the formed interference fringes occurs and information light is reproduced.

  In recent years, volume holography, particularly digital volume holography, has been developed in practical use for ultra-high density optical recording and has attracted attention. Volume holography is a method of writing interference fringes in three dimensions by actively utilizing the thickness direction of the optical recording medium. Increasing the thickness increases the diffraction efficiency and increases the recording capacity by using multiple recording. There is a feature that can be achieved. Digital volume holography is a computer-oriented holographic recording method that uses a recording medium and a recording method similar to those of volume holography, but restricts image information to be recorded to a binarized digital pattern. In this digital volume holography, for example, image information such as an analog picture is once digitized, developed into two-dimensional digital pattern information, and recorded as image information. At the time of reproduction, the digital pattern information is read and decoded so that the original image information is restored and displayed. As a result, even if the S / N ratio (signal-to-noise ratio) is somewhat poor during reproduction, the original information can be reproduced with high fidelity by performing differential detection or performing error correction by encoding binary data. Can be reproduced (see Patent Document 1).

For example, Patent Document 2 discloses the use of a urethane matrix and a phenyl acrylate derivative in a photopolymer holographic optical recording medium. However, in the normal photopolymer system, volume shrinkage is accompanied when the monomer is polymerized. Volume shrinkage causes a decrease in recording capacity. Patent Document 3 proposes forming a recording layer using radical ring-opening polymerization for the purpose of improving the storage capacity. However, it was still not enough storage capacity. In addition, the volume shrinkage causes distortion of recording interference fringes, which causes an error during data input / output, resulting in a decrease in recording sensitivity.
Japanese Patent Laid-Open No. 11-311936 JP-T-2005-502918 US Pat. No. 4,959,284

  Accordingly, an object of the present invention is to provide an optical recording compound suitable for digital volume holography having a large storage capacity and high sensitivity, an optical recording composition containing the compound, and ultrahigh density optical recording using the composition. It is to provide a possible holographic recording medium.

  As a result of intensive studies to achieve the above object, the present inventors have found that the optical recording composition containing the vinyl thiirane compound represented by the following general formula (I) has a small volume shrinkage and high sensitivity. The inventors have newly found that a holographic recording medium capable of recording can be provided, and have completed the present invention.

That is, the above object has been achieved by the following means.
[1] An optical recording compound which is a vinyl thiirane compound represented by the following general formula (I).
[In General Formula (I), R ¹ , R ² , R ³ and R ⁴ each independently represents a hydrogen atom or a substituent. ]
[2] In general formula (I), R ¹ represents a hydrogen atom, an alkyl group, an aryl group, an alkoxy group, a heterocyclic group or a halogen group, and R ² , R ³ and R ⁴ are each independently a hydrogen atom, The compound for optical recording according to [1], which represents an alkyl group, an aryl group, or a heterocyclic group.
[3] In general formula (I), R ¹ represents a hydrogen atom, an alkyl group or an aryl group, and R ² , R ³ and R ⁴ each independently represents a hydrogen atom, an alkyl group, an aryl group or a heterocyclic group. The optical recording compound according to claim 1 represented.
[4] In general formula (I), R ¹ represents a hydrogen atom or an aryl group, and R ² , R ³ and R ⁴ each independently represents a hydrogen atom, an alkyl group, an aryl group or a heterocyclic group [1 ] The optical recording compound described in the above.
[5] In general formula (I), R ¹ represents a hydrogen atom, R ² and R ³ each independently represent a hydrogen atom, an alkyl group, an aryl group or a heterocyclic group, and R ⁴ represents a hydrogen atom. [1] The optical recording compound according to [1].
[6] An optical recording composition containing the optical recording compound according to any one of [1] to [5].
[7] The optical recording composition according to [6], further comprising a thermosetting compound.
[8] The optical recording composition according to [7], wherein the thermosetting compound includes a polyfunctional isocyanate and a polyfunctional alcohol.
[9] The optical recording composition according to any one of [6] to [8], further containing a photoradical polymerization initiator.
[10] The optical recording composition according to any one of [6] to [9], which is a holographic recording composition.
[11] A holographic recording medium having a recording layer containing the optical recording compound according to any one of [1] to [5].
[12] The holographic recording medium according to [11], wherein the recording layer is a recording layer formed from the optical recording composition according to any one of [6] to [10].

  According to the present invention, it is possible to provide a holographic recording medium capable of highly sensitive recording / reproduction with reduced volume shrinkage. The holographic recording medium of the present invention is suitable as a recording medium for digital volume holography, which has a small volume shrinkage and can perform ultra-high density recording, and can achieve volume holography, in particular, use of an inexpensive laser and shortened writing time. It is.

[Compound for optical recording]
The optical recording compound of the present invention is a vinyl thiirane compound represented by the following general formula (I). The vinyl thiirane compound represented by the general formula (I) can be used as a recording material in various recording methods for recording information by light irradiation, and is particularly preferably used as a holographic recording compound, particularly volume holographic recording. It is suitable as a compound for use. As described above, holographic recording is information recording in which information light containing information and reference light are superimposed in a recording layer and information is recorded by writing an interference image formed at that time in the recording layer. Volume holographic recording is an information recording method in which an interference image is three-dimensionally written on a recording layer in holographic recording. In the present invention, the “holographic recording compound” refers to a compound capable of recording interference fringes as refractive index modulation directly or indirectly by light irradiation for information recording. The compound represented by the general formula (I) undergoes a polymerization reaction directly by light irradiation or by the action of a photopolymerization initiator, whereby interference fringes can be recorded as refractive index modulation.
Hereinafter, the optical recording compound of the present invention will be described in more detail.

Vinylthiirane compound represented by general formula (I)

In general formula (I), R ¹ , R ² , R ³ and R ⁴ each independently represents a hydrogen atom or a substituent.
Details of the general formula (I) will be described below.

The substituents represented by R ¹ , R ² , R ³ and R ⁴ are not particularly limited, and examples thereof include alkyl groups, aryl groups, heterocyclic groups, alkoxy groups, aryloxy groups, alkylthio groups, Examples include arylthio group, alkoxycarbonyl group, aryloxycarbonyl group, acyloxy group, acylamino group, sulfonylamino group, amino group, acyl group, cyano group, and halogen group.

  The alkyl group may be linear or branched, and may be unsubstituted or may have a substituent. The number of carbon atoms is preferably 1 to 30, and more preferably 1 to 20. As such an alkyl group, for example, methyl group, ethyl group, normal propyl group, isopropyl group, normal butyl group, isobutyl group, tertiary butyl group, pentyl group, cyclopentyl group, hexyl group, cyclohexyl group, heptyl group, Examples include octyl group, tertiary octyl group, 2-ethylhexyl group, decyl group, dodecyl group, octadecyl group, 2,3-dibromopropyl group, adamantyl group, benzyl group and 4-bromobenzyl group. These may further have a substituent.

  The aryl group may be unsubstituted or may have a substituent. The number of carbon atoms is preferably 6-30, and particularly preferably 6-20. Specific examples of the aryl group include a phenyl group, a naphthyl group, and an anthranyl group. These may further have a substituent.

  As the heterocyclic group, a heterocyclic group having 4 to 14 carbon atoms is preferable, a heterocyclic group having 4 to 10 carbon atoms is more preferable, and a heterocyclic group having 5 carbon atoms is particularly preferable. Specific examples of the heterocyclic group include a pyridine ring, a piperazine ring, a thiophene ring, a pyrrole ring, an imidazole ring, an oxazole ring, and a thiazole ring. These may further have a substituent. Of the heterocycles, a pyridine ring is particularly preferred.

  The alkoxy group may be linear or branched, and may be unsubstituted or have a substituent. The number of carbon atoms is preferably 1 to 30, and more preferably 1 to 20. Examples of such alkoxy groups include methoxy, ethoxy, normal propyloxy, isopropyloxy, normal butyloxy, isobutyloxy, tertiary butyloxy, pentyloxy, cyclopentyloxy, hexyloxy Group, cyclohexyloxy group, heptyloxy group, octyloxy group, tertiary octyloxy group, 2-ethylhexyloxy group, decyloxy group, dodecyloxy group, octadecyloxy group, 2,3-dibromopropyloxy group, adamantyloxy group, Examples include benzyloxy group and 4-bromobenzyloxy group. These may further have a substituent.

  The aryloxy group may be unsubstituted or may have a substituent. The number of carbon atoms is preferably 6-30, and particularly preferably 6-20. For example, a phenyloxy group, a naphthyloxy group, an anthranyloxy group, etc. are mentioned. These may further have a substituent.

  The alkylthio group may be linear or branched, and may be unsubstituted or have a substituent. The number of carbon atoms is preferably 1 to 30, and more preferably 1 to 20. Examples of such an alkylthio group include a methylthio group, an ethylthio group, a normal propylthio group, an isopropylthio group, a normal butylthio group, an isobutylthio group, a tertiary butylthio group, a pentylthio group, a cyclopentylthio group, a hexylthio group, Cyclohexylthio group, heptylthio group, octylthio group, tertiary octylthio group, 2-ethylhexylthio group, decylthio group, dodecylthio group, octadecylthio group, 2,3-dibromopropylthio group, adamantylthio group, benzylthio group, 4- Examples include a bromobenzylthio group. These may further have a substituent.

  The arylthio group may be unsubstituted or may have a substituent. The number of carbon atoms is preferably 6-30, and particularly preferably 6-20. For example, a phenylthio group, a naphthylthio group, an anthranylthio group, etc. are mentioned. These may further have a substituent.

  Examples of the alkoxycarbonyl group include a methyloxycarbonyl group, an ethyloxycarbonyl group, a normal propyloxycarbonyl group, an isopropyloxycarbonyl group, a normal butyloxycarbonyl group, an isobutyloxycarbonyl group, a tertiary butyloxycarbonyl group, and a pentyloxycarbonyl group. , Cyclopentyloxycarbonyl group, hexyloxycarbonyl group, cyclohexyloxycarbonyl group, heptyloxycarbonyl group, octyloxycarbonyl group, tertiary octyloxycarbonyl group, 2-ethylhexyloxycarbonyl group, decyloxycarbonyl group, dodecyloxycarbonyl group, etc. Is mentioned. These may further have a substituent.

  The aryloxycarbonyl group may be unsubstituted or may have a substituent. The number of carbon atoms is preferably 7-30, and particularly preferably 7-20. For example, a phenyloxycarbonyl group, a naphthyloxycarbonyl group, an anthranyloxycarbonyl group, etc. are mentioned. These may further have a substituent.

  Examples of the acyloxy group include a methylcarbonyloxy group, an ethylcarbonyloxy group, a normal propylcarbonyloxy group, an isopropylcarbonyloxy group, a normal butylcarbonyloxy group, an isobutylcarbonyloxy group, a tertiary butylcarbonyloxy group, a pentylcarbonyloxy group, Cyclopentylcarbonyloxy group, hexylcarbonyloxy group, cyclohexylcarbonyloxy group, heptylcarbonyloxy group, octylcarbonyloxy group, tertiary octylcarbonyloxy group, 2-ethylhexylcarbonyloxy group, decylcarbonyloxy group, dodecylcarbonyloxy group, benzoyl An oxy group etc. are mentioned. These may further have a substituent.

  Examples of the acylamino group include a methylcarbonylamino group, an ethylcarbonylamino group, and a phenylcarbonylamino group. These may further have a substituent.

  Examples of the sulfonylamino group include a methylsulfonylamino group, an ethylsulfonylamino group, and a phenylsulfonylamino group. These may further have a substituent.

  The amino group may be a mono- or di-substituted amino group, and a di-substituted amino group is more preferable. For example, a dimethylamino group, a diphenylamino group, etc. are mentioned. These may further have a substituent.

  Examples of the acyl group include an acetyl group and a benzoyl group. These may further have a substituent.

  Examples of the halogen group include a chloro group, a bromo group, and an iodo group, and a bromo group is preferable.

In the general formula (I), when the group represented by R ¹ , R ² , R ³ , or R ⁴ further has a substituent, the substituent includes a halogen atom, an alkyl group, an alkenyl group, an alkoxy group, an aryloxy group. Alkylthio group, alkoxycarbonyl group, aryloxycarbonyl group, amino group, acyl group, alkylaminocarbonyl group, arylaminocarbonyl group, sulfonamido group, cyano group, carboxy group, hydroxyl group, sulfonic acid group and the like. Among these, a halogen atom, an alkoxy group, and an alkylthio group are particularly preferable. Moreover, when the vinyl thiirane compound represented by general formula (I) substitutes as a substituent, the compound represented by general formula (I) represents a polyfunctional compound.

In a preferred embodiment of the compound represented by the general formula (I), R ¹ represents a hydrogen atom, an alkyl group, an aryl group, an alkoxy group, a heterocyclic group, or a halogen group, and R ² , R ³ and R ⁴ are And compounds each independently representing a hydrogen atom, an alkyl group, an aryl group, or a heterocyclic group.
In a more preferred embodiment, R ¹ represents a hydrogen atom, an alkyl group, or an aryl group, and R ² , R ^3, and R ⁴ each independently represents a hydrogen atom, an alkyl group, an aryl group, or a heterocyclic group Can be mentioned.
In a more preferred embodiment, R ¹ represents a hydrogen atom or an aryl group, and R ² , R ^3, and R ⁴ each independently represents a compound that represents a hydrogen atom, an alkyl group, an aryl group, or a heterocyclic group. Can do.
In a most preferred embodiment, R ₁ represents a hydrogen atom, R ² and R ³ each independently represents a hydrogen atom, an alkyl group, an aryl group, or a heterocyclic group, and R ⁴ represents a compound that represents a hydrogen atom. Can be mentioned.

  Specific examples of the optical recording compound of the present invention are shown below. However, the present invention is not limited to the following specific examples.

  For example, J. Org. Chem. 1979, 44, 2244., J. Am. Chem. Soc. 1998, 120, 1922., Tetrahedron Lett 1999, 40, 3791., Tetrahedron 2002, 58, 4517 and the like. The radical polymerizability of vinylthiirane compounds is described in J. Polym. Sci. Part A-1. 1970, 8, 2579.

[Optical recording composition]
The optical recording composition of the present invention contains at least a vinyl thiirane compound represented by the general formula (I). The vinyl thiirane compound represented by the general formula (I) may be used alone or in combination of two or more. The content of the vinyl thiirane compound represented by the general formula (I) in the optical recording composition of the present invention is not particularly limited and can be appropriately set according to the purpose, but is preferably 1 to 50% by mass. 1-30 mass% is more preferable, and 3-10 mass% is still more preferable. If the content is 50% by mass or less, the stability of the interference image can be easily secured, and if it is 1% by mass or more, desirable performance can be obtained in terms of diffraction efficiency.

  The optical recording composition of the present invention may contain only the vinyl thiirane compound represented by the general formula (I) as the recording compound, and may contain other polymerizable monomers together with the vinyl thiirane compound. When the vinyl thiirane compound represented by the general formula (I) is used in combination with another polymerizable monomer, the amount of the polymerizable monomer used in the total recording compound is preferably 50% by mass or less.

  Examples of other monomers used in combination include acryloylmorpholine, phenoxyethyl acrylate, isobornyl acrylate, 2-hydroxypropyl acrylate, 2-ethylhexyl acrylate, 1,6-hexanediol diacrylate, tripropylene glycol diacrylate, and neopentyl. Glycol PO-modified diacrylate, 1,9-nonanediol diacrylate, hydroxypivalate neopentyl glycol diacrylate, EO-modified bisphenol A diacrylate, polyethylene glycol diacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, pentaerythritol hexaacrylate , EO-modified glycerol triacrylate, trimethylol proppant Acrylate, EO-modified trimethylolpropane triacrylate, 2-naphth-1-oxyethyl acrylate, 2-carbazoyl-9-ylethyl acrylate, (trimethylsilyloxy) dimethylsilylpropyl acrylate, vinyl-1-naphthoate, 2,4,6 -Tribromophenyl acrylate, pentabromo acrylate, phenylthioethyl acrylate, tetrahydrofurfuryl acrylate, bisphenoxyethanol fluorene acrylate, styrene, p-chlorostyrene, N-vinyl carbazole, N-vinyl pyropydon and the like. Among these, phenoxyethyl acrylate, 2,4,6-tribromophenyl acrylate, pentabromoacrylate, and bisphenoxyethanol full orange acrylate are preferable, and 2,4,6-tribromophenyl acrylate and bisphenoxyethanol full orange acrylate are more preferable.

Photopolymerization initiator The optical recording composition of the present invention is preferably used as a holographic recording composition, and particularly suitable as a volume holographic recording composition. When the optical recording composition of the present invention is used as a holographic recording composition, the compound represented by the general formula (I) can function as a recording monomer. In the present invention, the “recording monomer” means a monomer capable of causing a polymerization reaction directly by light irradiation for information recording or by the action of a photopolymerization initiator, thereby recording interference fringes as refractive index modulation. It shall be said. The optical recording composition of the present invention can contain a photopolymerization initiator together with the vinyl thiirane compound represented by the general formula (I). The photopolymerization initiator is not particularly limited as long as it has sensitivity to the recording light, but a photoradical polymerization initiator is preferable in view of the efficiency of the polymerization reaction.

Examples of the photo radical polymerization initiator include 2,2′-bis (o-chlorophenyl) -4,4 ′, 5,5′-tetraphenyl-1,1′-biimidazole, 2,4,6-tris. (Trichloromethyl) -1,3,5-triazine, 2,4-bis (trichloromethyl) -6- (p-methoxyphenylvinyl) -1,3,5-triazine, diphenyliodonium tetrafluoroborate, diphenyliodonium hexa Fluorophosphate, 4,4′-di-t-butyldiphenyliodonium tetrafluoroborate, 4-diethylaminophenylbenzenediazonium hexafluorophosphate, benzoin, 2-hydroxy-2-methyl-1-phenylpropan-2-one, benzophenone, Thioxanthone, 2,4,6-trimethylbenzoyl Phenylacylphosphine oxide, triphenylbutylborate tetraethylammonium, bis (η5-2,4-cyclopentadien-1-yl) bis [2,6-difluoro-3- (1H-pyrrol-1-yl) phenyltitanium], etc. Is mentioned. These may be used individually by 1 type and may use 2 or more types together. Moreover, you may use together the sensitizing dye mentioned later according to the wavelength of the light to irradiate.
The content of the photopolymerization initiator in the optical recording composition of the present invention is preferably 0.01 to 5% by mass, and more preferably 1 to 3% by mass. When the content is 0.01% by mass or more, an interference image can be secured with high sensitivity. When the content is 5% by mass or less, a recording layer having a sufficient transmittance for recording light and showing good recording sensitivity can be formed.

The recording layer of the matrix optical recording medium contains a monomer generally called a matrix, which is related to recording and storage, and a polymer for holding a photopolymerization initiator. The matrix is used for the purpose of enhancing the effects of improving coating properties, film strength, and hologram recording characteristics. The optical recording composition of the present invention can contain a curable compound as a matrix binder and / or a matrix-forming component (matrix precursor). A method of forming a matrix by applying a composition containing a matrix precursor to, for example, a substrate surface and then performing a curing treatment is preferable because a recording layer can be formed without using a solvent or using a small amount of solvent. . As the curable compound, a photocurable compound that is cured by light irradiation using a thermosetting compound or a catalyst can be used, and a thermosetting compound is preferable in terms of recording characteristics.

There is no restriction | limiting in particular as a thermosetting compound contained in the composition for optical recording of this invention. The thermosetting matrix contained in the recording layer can be appropriately selected depending on the purpose. For example, an epoxy compound, a melamine compound, or formalin formed from a urethane resin or oxirane compound formed from an isocyanate compound and an alcohol compound. Examples thereof include polymers and polymers obtained by polymerizing ester compounds and amide compounds of unsaturated acids such as (meth) acrylic acid and itaconic acid.
Among them, a polyurethane matrix formed from an isocyanate compound and an alcohol compound is preferable, and a three-dimensional polyurethane matrix formed from a polyfunctional isocyanate and a polyfunctional alcohol is most preferable from the viewpoint of record retention.
The polyfunctional isocyanate and polyfunctional alcohol that can form the polyurethane matrix will be described in more detail below.

  Specific examples of the polyfunctional isocyanate include biscyclohexylmethane diisocyanate, hexamethylene diisocyanate, phenylene-1,3-diisocyanate, phenylene-1,4-diisocyanate, 1-methoxyphenylene-2,4-diisocyanate, and 1-methyl. Phenylene-2,4-diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 1,3-xylylene diisocyanate, 1,4-xylylene diisocyanate, biphenylene-4,4′-diisocyanate, 3 , 3'-dimethoxybiphenylene-4,4'-diisocyanate, 3,3'-dimethylbiphenylene-4,4'-diisocyanate, diphenylmethane-2,4'-diisocyanate, diphenylmethane-4,4'-diisocyanate Anate, 3,3′-dimethoxydiphenylmethane-4,4′-diisocyanate, 3,3′-dimethyldiphenylmethane-4,4′-diisocyanate, naphthylene-1,5-diisocyanate, cyclobutylene-1,3-diisocyanate, cyclo Pentylene-1,3-diisocyanate, cyclohexylene-1,3-diisocyanate, cyclohexylene-1,4-diisocyanate, 1-methylcyclohexylene-2,4-diisocyanate, 1-methylcyclohexylene-2,6-diisocyanate 1-isocyanate-3,3,5-trimethyl-5-isocyanatomethylcyclohexane, cyclohexane-1,3-bis (methylisocyanate), cyclohexane-1,4-bis (methylisocyanate), isophorone diisocyanate , Dicyclohexylmethane-2,4′-diisocyanate, dicyclohexylmethane-4,4′-diisocyanate, ethylene diisocyanate, tetramethylene-1,4-diisocyanate, hexamethylene-1,6-diisocyanate, dodecamethylene-1,12- Diisocyanate, phenyl-1,3,5-triisocyanate, diphenylmethane-2,4,4'-triisocyanate, diphenylmethane-2,5,4'-triisocyanate, triphenylmethane-2,4 ', 4 "-triisocyanate Isocyanate, triphenylmethane-4,4 ', 4 "-triisocyanate, diphenylmethane-2,4,2', 4'-tetraisocyanate, diphenylmethane-2,5,2 ', 5'-tetraisocyanate, cyclohexane-1 , 3,5-Triisocy Nate, cyclohexane-1,3,5-tris (methyl isocyanate), 3,5-dimethylcyclohexane-1,3,5-tris (methyl isocyanate), 1,3,5-trimethylcyclohexane-1,3,5- Stoichiometric excess of tris (methyl isocyanate), dicyclohexylmethane-2,4,2′-triisocyanate, dicyclohexylmethane-2,4,4′-triisocyanine lysine diisocyanate methyl ester, or these organic isocyanate compounds And a bifunctional isocyanate prepolymer obtained by reaction with a polyfunctional active hydrogen-containing compound. Among these, biscyclohexylmethane diisocyanate and hexamethylene diisocyanate are particularly preferable. These may be used individually by 1 type and may use 2 or more types together.

  A polyfunctional alcohol may be used individually by 1 type, and may use 2 or more types together. Polyfunctional alcohols include glycols such as ethylene glycol, triethylene glycol, diethylene glycol, polyethylene glycol, propylene glycol, polypropylene glycol, and neopentyl glycol; diols such as butanediol, pentanediol, hexanediol, heptanediol, and tetramethylene glycol Such as bisphenols, compounds obtained by modifying these polyfunctional alcohols with polyethyleneoxy chain or polypropyleneoxy chain, triols such as glycerin, trimethylolpropane, butanetriol, pentanetriol, hexanetriol, decanetriol, etc. Examples include compounds obtained by modifying functional alcohols with polyethyleneoxy chains or polypropyleneoxy chains.

  The content of the matrix-forming component (or matrix) in the optical recording composition of the present invention is preferably 10 to 95% by mass, and more preferably 35 to 90% by mass. If the content is 10% by mass or more, a stable interference image can be easily obtained, and if it is 95% by mass or less, desirable performance can be obtained in terms of diffraction efficiency.

Other Components A polymerization inhibitor and an antioxidant may be added to the optical recording composition of the present invention as needed for the purpose of improving the storage stability of the optical recording composition.
Examples of the polymerization inhibitor or antioxidant include hydroquinone, p-benzoquinone, hydroquinone monomethyl ether, 2,6-ditertiary butyl-p-cresol, 2,2′-methylenebis (4-methyl-6-tertiary- Butylphenol), trifel phosphite, trisnonylphenyl phosphite, phenothiazine, N-isopropyl-N′-phenyl-p-phenylenediamine and the like.
The addition amount of the polymerization inhibitor or antioxidant is preferably 3% by mass or less based on the total amount of the recording monomer. When the addition amount exceeds 3% by mass, the polymerization may be slowed or may not be polymerized when it is remarkable.

A sensitizing dye can be added to the optical recording composition of the present invention as necessary. Examples of the sensitizing dye include “Research Disclosure, Vol. 200, December 1980, Item 20036” and “sensitizer” (p.160 to p.163, Kodansha; Katsumi Tokumaru and Nobu Okawara, edited by 1987. ) And the like can be used.
Specific examples of the sensitizing dye include a 3-ketocoumarin compound described in JP-A-58-15603, a thiopyrylium salt described in JP-A-58-40302, and JP-B-59-28328. The naphthothiazole merocyanine compound described in JP-A-60-53300, the merocyanine compound described in JP-B-61-9621, JP-A-62-2842, JP-A-59-89303, and JP-A-60-60104 Can be mentioned.
Further, the dyes described in “Functional dye chemistry” (1981, CMC Publishing Co., p.393 to p.416), “Coloring materials” (60 [4] 212-224 (1987)), and the like are also included. be able to. Specific examples include a cationic methine dye, a cationic carbonium dye, a cationic quinoneimine dye, a cationic indoline dye, and a cationic styryl dye.
In addition, coumarin (including ketocoumarin or sulfonocoumarin) dyes, melostyryl dyes, oxonol dyes, hemioxonol dyes, etc .; non-ketopolymethine dyes, triarylmethane dyes, xanthene dyes, anthracene dyes, rhodamine dyes, acridine dyes Non-keto dyes such as aniline dyes and azo dyes; Non-ketopolymethine dyes such as azomethine dyes, cyanine dyes, carbocyanine dyes, dicarbocyanine dyes, tricarbocyanine dyes, hemicyanine dyes, styryl dyes; azine dyes, oxazine dyes, thiazines Dyestuffs, quinoline dyes, quinoneimine dyes such as thiazole dyes, and the like are also included in the spectral sensitizing dyes.
The said sensitizing dye may be used individually by 1 type, and may be used in combination of 2 or more type.

The optical recording composition of the present invention may contain a photothermal conversion material for the purpose of improving the sensitivity of the recording layer formed from the optical recording composition.
The photothermal conversion material is not particularly limited and can be appropriately selected depending on the intended function and performance. For example, it can be easily added to the recording layer together with a photopolymer, or can cause scattering of incident light. Organic dyes are preferred from the standpoint of the absence of properties, and infrared absorbing dyes are preferred in that they do not absorb or scatter light from the light source used for recording.
The infrared absorbing dye is not particularly limited and may be appropriately selected depending on the intended purpose. Cationic dyes, complex salt-forming dyes, quinone neutral dyes, and the like are preferable. The maximum absorption wavelength of the infrared absorbing dye is preferably in the range of 600 to 1,000 nm, and more preferably in the range of 700 to 900 nm.
The content of the infrared absorbing dye can be determined by the absorbance of the wavelength having the highest absorbance in the infrared region in the recording layer formed from the optical recording composition of the present invention. As this light absorbency, the range of 0.1-2.5 is preferable, and the range of 0.2-2.0 is more preferable.

  In the optical recording composition of the present invention, if necessary, a component that diffuses in the direction opposite to the polymerization component may be added to relieve the volume change during polymerization, or an acid cleavage structure may be added. You may add separately the compound which has it in addition to a polymer.

  The optical recording composition of the present invention can be used for various holographic recording compositions capable of recording information by irradiation with light containing information, and is particularly suitable as a volume holographic recording composition. It is. A recording layer can be formed by applying the optical recording composition of the present invention onto a substrate, for example. When the optical recording composition of the present invention contains a thermosetting compound as described above, the matrix can be formed by allowing the curing reaction to proceed by placing it under heating after coating. What is necessary is just to determine a heating condition according to the thermosetting compound to be used. If the optical recording composition has a sufficiently low viscosity, the recording layer can be formed by casting. On the other hand, if the viscosity is too high to be cast, a recording layer is placed on the lower substrate using a dispenser, and the recording layer is spread over the entire surface by pressing on the recording layer so as to cover the upper substrate. be able to.

[Holographic recording media]
The holographic recording medium of the present invention has a recording layer containing a vinyl thiirane compound represented by the general formula (I). The recording layer can be formed from the optical recording composition of the present invention. For example, a recording layer comprising the optical recording composition of the present invention can be formed by the above-described method.

  The holographic recording medium of the present invention contains a vinyl thiirane compound represented by the general formula (I) in the recording layer. Since the compound represented by the general formula (I) has little volume shrinkage, it is possible to form a high-density recording medium that is excellent in multiple recording characteristics and capable of high-sensitivity recording / reproduction. As a method for confirming that the recording layer contains the compound represented by the general formula (I), the recording layer portion is extracted with tetrahydrofuran (THF) or dioxane, and gas chromatography (GC) is used. Thus, a method for detecting the peak of the compound represented by the general formula (I) can be used. The content of the compound represented by the general formula (I) in the recording layer is preferably 1 to 50% by mass, and 1 to 30% by mass is the same as the content in the optical recording composition of the present invention. More preferred is 3 to 10% by mass. If the content is 50% by mass or less, the stability of the interference image can be easily secured, and if it is 1% by mass or more, desirable performance can be obtained in terms of diffraction efficiency. Details of each component in the recording layer of the holographic recording medium of the present invention are as described above for the optical recording composition of the present invention.

  The holographic recording medium of the present invention includes the recording layer (holographic recording layer), and preferably includes a lower substrate, a filter layer, a holographic recording layer, and an upper substrate. And other layers such as a reflective film, a filter layer, a first gap layer, and a second gap layer.

  The holographic recording medium of the present invention is capable of recording / reproducing information using the principle of hologram, and is a volume for recording a large amount of information such as a relatively thin planar hologram or a three-dimensional image for recording information such as two dimensions. It may be a hologram, and may be either a transmission type or a reflection type. The holographic recording medium of the present invention is suitable as a volume holographic recording medium for which high recording density is required because high capacity information recording is possible.

  Further, the recording method of the hologram on the holographic recording medium of the present invention is not particularly limited, and for example, an amplitude hologram, a phase hologram, a blazed hologram, a complex amplitude hologram, or the like may be used. Among these, information recording in the volume holographic recording area is performed by irradiating the volume holographic recording area with information light and reference light as a coaxial light beam, and recording information by an interference pattern due to interference between the information light and the reference light. The so-called collinear method is particularly preferable.

  Below, the detail of the board | substrate and each layer which may be contained in the holographic recording medium of this invention is demonstrated one by one.

-Board-
There is no restriction | limiting in particular about the shape, a structure, a magnitude | size, etc., a board | substrate can be suitably selected according to the objective. Examples of the shape include a disk shape and a card shape, and a material that can ensure the mechanical strength of the holographic recording medium should be selected. In addition, when light used for recording and reproduction enters through the substrate, it is preferable that the light is sufficiently transparent in the wavelength region of the light used.

  As the substrate material, glass, ceramics, resin, and the like are usually used, and resin is particularly preferable from the viewpoint of moldability and cost. Examples of the resin include polycarbonate resin, acrylic resin, epoxy resin, polystyrene resin, acrylonitrile-styrene copolymer, polyethylene resin, polypropylene resin, silicone resin, fluorine resin, ABS resin, urethane resin, and the like. Among these, polycarbonate resin and acrylic resin are particularly preferable from the viewpoints of moldability, optical characteristics, and cost. As a board | substrate, what was synthesize | combined suitably may be used and a commercial item may be used.

  The substrate is usually provided with a plurality of address-servo areas as linearly extending positioning areas at predetermined angular intervals, and a sector-shaped section between adjacent address-servo areas is a data area. . In the address-servo area, information for performing focus servo and tracking servo by the sampled servo method and address information are recorded in advance by embossed pits (servo pits) or the like (preformat). Note that the focus servo can be performed using the reflective surface of the reflective film. As information for performing the tracking servo, for example, a wobble pit can be used. In the case where the holographic recording medium has a card shape, the servo pit pattern may be omitted.

  There is no restriction | limiting in particular as thickness of a board | substrate, According to the objective, it can select suitably, 0.1-5 mm is preferable and 0.3-2 mm is more preferable. If the thickness of the substrate is 0.1 mm or more, the distortion of the shape during storage of the disc can be suppressed, and if it is 5 mm or less, the mass of the entire disc increases and an excessive load is applied to the drive motor. It can be avoided.

-Recording layer-
The recording layer can be formed from the optical recording composition of the present invention, and information can be recorded using holography. There is no restriction | limiting in particular as thickness of a recording layer, According to the objective, it can select suitably. If the thickness of the recording layer is in the range of 1 to 1,000 μm, a sufficient S / N ratio can be obtained even if shift multiplexing of 10 to 300 is performed, and if it is in the range of 100 to 700 μm, this is remarkable. This is advantageous.

-Reflective film-
The reflective film can be formed on the servo pit pattern surface of the substrate.
As a material for the reflective film, a material having a high reflectance with respect to information light and reference light is preferably used. When the wavelength of light used as information light and reference light is 400 to 780 nm, for example, it is preferable to use Al, Al alloy, Ag, Ag alloy, or the like. When the wavelength of light used as information light and reference light is 650 nm or more, it is preferable to use Al, Al alloy, Ag, Ag alloy, Au, Cu alloy, TiN, or the like.
In addition, by using an optical recording medium that reflects light and can be added or erased as a reflective film, for example, a DVD (digital video disk), it is possible to rewrite to what area the hologram has been recorded. It is also possible to additionally write and rewrite directory information such as in which part an error exists and how the alternation process was performed without affecting the hologram.

The method for forming the reflective film is not particularly limited and can be appropriately selected according to the purpose. Various vapor deposition methods such as vacuum deposition, sputtering, plasma CVD, photo CVD, ion plating An electron beam evaporation method or the like is used. Among these, the sputtering method is excellent in terms of mass productivity and film quality.
The thickness of the reflective film is preferably 50 nm or more, and more preferably 100 nm or more so that sufficient reflectance can be achieved.

-Filter layer-
The filter layer can be provided on the servo pits of the substrate, on the reflective layer, or on the first gap layer described later.
The filter layer has a wavelength selective reflection function that reflects only light of a specific wavelength from among a plurality of types of light rays, transmits the first light, and reflects the second light. In particular, even if the incident angle changes, the selective reflection wavelength does not shift, and the function of preventing irregular reflection from the reflection film of the recording medium by the information light and the reference light and the generation of noise are also provided. By laminating filter layers, optical recording with high resolution and excellent diffraction efficiency can be performed.
There is no restriction | limiting in particular as a filter layer, According to the objective, it can select suitably, For example, a dichroic mirror layer, a coloring material containing layer, a dielectric material vapor deposition layer, a single layer or two or more cholesteric layers, and as needed It is possible to form a laminate in which at least one of the other layers appropriately selected is laminated. Although the thickness is not specifically limited, For example, it is about 0.5-20 micrometers.
The filter layer may be directly laminated on the substrate together with the recording layer or the like, or may be laminated on a substrate such as a film to produce a filter layer, which may be laminated on the substrate.

-First gap layer-
The first gap layer is provided between the filter layer and the reflective film as necessary, and is formed for the purpose of smoothing the lower substrate surface. It is also effective for adjusting the size of the hologram generated in the recording layer. That is, since it is necessary for the recording layer to form an interference area for the recording reference light and the information light to a certain extent, it is effective to provide a gap between the recording layer and the servo pit pattern.

The first gap layer can be formed, for example, by applying a material such as an ultraviolet curable resin on the servo pit pattern by spin coating or the like and curing it. Moreover, when using what apply | coated and formed on the transparent base material as a filter layer, this transparent base material will work | function also as a 1st gap layer.
There is no restriction | limiting in particular as thickness of a 1st gap layer, According to the objective, it can select suitably, 1-200 micrometers is preferable.

-Second gap layer-
The second gap layer is provided between the recording layer and the filter layer as necessary.
There is no restriction | limiting in particular as a material of a 2nd gap layer, According to the objective, it can select suitably, For example, a triacetyl cellulose (TAC), a polycarbonate (PC), a polyethylene terephthalate (PET), a polystyrene (PS) Transparent resin films such as polysulfone (PSF), polyvinyl alcohol (PVA), polymethyl methacrylate = polymethyl methacrylate (PMMA), etc., or JSR brand name ARTON film or Nippon Zeon brand name ZEONOR Examples thereof include norbornene resin films. Among these, those having high isotropic properties are preferred, and TAC, PC, trade name ARTON, and trade name ZEONOR are particularly preferred.
There is no restriction | limiting in particular as thickness of a 2nd gap layer, According to the objective, it can select suitably, 1-200 micrometers is preferable.
Hereinafter, the holographic recording medium of the present invention will be described in more detail based on specific embodiments. However, the present invention is not limited to the following specific embodiments.

<First embodiment>
FIG. 1 is a schematic cross-sectional view showing the configuration of the holographic recording medium according to the first embodiment. In the holographic recording medium 21 according to the first embodiment, a servo pit pattern 3 is formed on a polycarbonate resin substrate or glass substrate 1, and the servo pit pattern 3 is coated with aluminum, gold, platinum, or the like to be a reflective film 2 is provided. In FIG. 1, the servo pit pattern 3 is formed on the entire surface of the lower substrate 1. However, the servo pit pattern may be formed periodically. The height of the servo pit pattern 3 is usually 1750 mm (175 nm), which is sufficiently smaller than the thicknesses of the substrate and other layers.

  The first gap layer 8 is formed by applying a material such as an ultraviolet curable resin on the reflective film 2 of the lower substrate 1 by spin coating or the like. The first gap layer 8 is effective for protecting the reflective film 2 and adjusting the size of the hologram generated in the recording layer 4. That is, providing a gap between the recording layer 4 and the servo pit pattern 3 is effective for forming a recording reference light and information light interference region in the recording layer 4 to a certain size.

  A filter layer 6 is provided on the first gap layer 8, and a holographic recording medium 21 is configured by sandwiching the recording layer 4 between the filter layer 6 and the upper substrate 5 (polycarbonate resin substrate or glass substrate).

In FIG. 1, the filter layer 6 transmits only red light and does not transmit light of other colors. Therefore, since the information light, the recording and reproduction reference light are green or blue light, the light does not pass through the filter layer 6 and does not reach the reflection film 2 but becomes return light and is emitted from the incident / exit surface A. Become.
The filter layer 6 is a multilayer deposited film in which high refractive index layers and low refractive index layers are alternately stacked.
The filter layer 6 made of this multilayer deposited film may be directly formed on the first gap layer 8 by vacuum deposition, or a film in which the multilayer deposited film is formed on the substrate is punched into a holographic recording medium shape. May be.

  The holographic recording medium 21 in the present embodiment may have a disk shape or a card shape. In the case of a card shape, there is no need for the servo pit pattern. In the holographic recording medium 21, the lower substrate 1 is 0.6 mm, the first gap layer 8 is 100 μm, the filter layer 6 is 2 to 3 μm, the recording layer 4 is 0.6 mm, and the upper substrate 5 is 0.6 mm. The total thickness is about 1.9 mm.

Next, an optical system that can be used for recording and reproducing information on the holographic recording medium 21 will be described with reference to FIG.
First, light (red light) emitted from the servo laser is reflected almost 100% by the dichroic mirror 13 and passes through the objective lens 12. The servo light is irradiated onto the holographic recording medium 21 by the objective lens 12 so as to focus on the reflective film 2. That is, the dichroic mirror 13 transmits light having a wavelength of green or blue, and reflects light having a wavelength of red almost 100%. The servo light incident from the light incident / exit surface A of the holographic recording medium 21 passes through the upper substrate 5, the recording layer 4, the filter layer 6, and the first gap layer 8, is reflected by the reflective film 2, and again The first gap layer 8, the filter layer 6, the recording layer 4, and the upper substrate 5 are transmitted through the incident / exit surface A. The returned return light passes through the objective lens 12, is reflected almost 100% by the dichroic mirror 13, and servo information is detected by a servo information detector (not shown). The detected servo information is used for focus servo, tracking servo, slide servo, and the like. If the hologram material constituting the recording layer 4 is not sensitive to red light, even if the servo light passes through the recording layer 4 or the servo light is irregularly reflected by the reflective film 2, Has no effect. Further, since the return light of the servo light reflected by the reflection film 2 is reflected almost 100% by the dichroic mirror 13, the servo light is detected by the CMOS sensor or the CCD 14 for detecting the reproduced image. In addition, there is no noise with respect to the reproduction light.

  The information light and the recording reference light generated from the recording / reproducing laser pass through the polarizing plate 16 to become linearly polarized light, pass through the half mirror 17 and pass through the quarter wavelength plate 15. It becomes circularly polarized light. Through the dichroic mirror 13, the objective lens 12 irradiates the holographic recording medium 21 with information light and recording reference light so as to generate an interference pattern in the recording layer 4. The information light and the recording reference light enter from the incident / exit surface A and interfere with each other in the recording layer 4 to generate an interference pattern there. Thereafter, the information light and the recording reference light pass through the recording layer 4 and enter the filter layer 6, but are reflected to the bottom surface of the filter layer 6 to become return light. That is, the information light and the recording reference light do not reach the reflective film 2. This is because the filter layer 6 is a multilayer deposited layer in which a plurality of high refractive index layers and low refractive index layers are alternately stacked, and has a property of transmitting only red light.

<Second Embodiment>
FIG. 2 is a schematic cross-sectional view showing the configuration of the holographic recording medium according to the second embodiment. In the holographic recording medium 22 according to the second embodiment, a servo pit pattern 3 is formed on a polycarbonate resin or glass substrate 1, and the surface of the servo pit pattern 3 is coated with aluminum, gold, platinum, etc. Is provided. The height of the servo pit pattern 3 is the same as that of the first embodiment in that it is normally 1750 mm (175 nm).

  The difference in structure between the second embodiment and the first embodiment is that the second gap layer 7 is provided between the filter layer 6 and the recording layer 4 in the holographic recording medium 22 according to the second embodiment. It is that. The second gap layer 7 has a point where information light and reproduction light are focused. If this area is filled with a photopolymer, excessive consumption of monomers due to overexposure occurs, resulting in a decrease in multiple recording capability. Therefore, it is effective to provide a non-reactive and transparent second gap layer.

  A filter layer 6, which is a multilayer deposited film in which a plurality of high refractive index layers and low refractive index layers are alternately stacked, is formed on the first gap layer 8 after the first gap layer 8 is formed. The thing similar to embodiment can be used.

  In the holographic recording medium 22 of the second embodiment, the lower substrate 1 is 1.0 mm, the first gap layer 8 is 100 μm, the filter layer 6 is 3 to 5 μm, the second gap layer 7 is 70 μm, and the recording layer 4. Is 0.6 mm, the upper substrate 5 is 0.4 mm thick, and the total thickness is about 2.2 mm.

  Next, when information is recorded or reproduced, red servo light and green information light and recording and reproduction reference light are applied to the holographic recording medium 22 of the second embodiment having the above-described structure. Is irradiated. The servo light enters from the incident / exit surface A, passes through the recording layer 4, the second gap layer 7, the filter layer 6, and the first gap layer 8 and is reflected by the reflective film 2 to become return light. The return light again passes through the first gap layer 8, the filter layer 6, the second gap layer 7, the recording layer 4, and the upper substrate 5 in this order, and is emitted from the incident / exit surface A. The emitted return light is used for focus servo, tracking servo, and the like. If the hologram material constituting the recording layer 4 is not sensitive to red light, even if the servo light passes through the recording layer 4 or the servo light is irregularly reflected by the reflective film 2, Has no effect. Green information light or the like enters from the incident / exit surface A, passes through the recording layer 4 and the second gap layer 7, is reflected by the filter layer 6, and becomes return light. The return light again passes through the second gap layer 7, the recording layer 4 and the upper substrate 5 in this order, and exits from the incident / exit surface A. Also during reproduction, not only the reproduction reference light but also the reproduction light generated by irradiating the reproduction reference light onto the recording layer 4 is emitted from the incident / exit surface A without reaching the reflection film 2. The optical operation in the vicinity of the holographic recording medium 22 (the objective lens 12, the filter layer 6, the CMOS sensor or the CCD 14 as a detector in FIG. 3) is the same as in the first embodiment, and a description thereof will be omitted.

  Next, a method for recording information on the holographic recording medium of the present invention will be described. The recording layer formed from the optical recording composition of the present invention is irradiated with information light and reference light to form an interference image on the recording layer, and then the recording layer on which the interference image is formed. The interference image can be fixed by irradiating the fixing light.

  As information light, coherent light can be used. An interference image generated by the interference between the information light and the reference light by irradiating the recording medium with the information light and the reference light so that the optical axis of the information light and the optical axis of the reference light are coaxial. Can be recorded on the recording layer. Specifically, the information light provided with a two-dimensional intensity distribution and the information light and a reference light having a substantially constant intensity are superposed inside the recording layer, and recording is performed using an interference pattern formed by them. Information can be recorded by creating a distribution of optical properties within the layer. The wavelengths of the information light and the reference light are preferably 400 nm or more, more preferably 400 to 2000 nm, and particularly preferably 400 to 700 nm.

  After performing information recording (interference image formation) by irradiation with information light and reference light, the interference image can be fixed by irradiating with fixing light. The wavelength of the fixing light is preferably less than 400 nm, more preferably 100 nm or more and less than 400 nm, and particularly preferably 200 nm or more and less than 400 nm.

  Information can be reproduced by irradiating the interference light formed by the above method with reference light. When reading (reproducing) the written information, the recording layer is irradiated with only the reference light in the same arrangement as during recording, and the reproduction light having an intensity distribution corresponding to the optical characteristic distribution formed inside the recording layer is obtained. The light is emitted from the recording layer.

Next, an optical recording / reproducing apparatus suitably used for recording and reproducing information on the holographic recording medium of the present invention will be described with reference to FIG.
The optical recording / reproducing apparatus 100 shown in FIG. 4 maintains a spindle 81 to which the holographic recording medium 20 is attached, a spindle motor 82 for rotating the spindle 81, and the rotational speed of the holographic recording medium 20 at a predetermined value. A spindle servo circuit 83 that controls the spindle motor 82 is provided.

  The optical recording / reproducing apparatus 100 records information by irradiating the holographic recording medium 20 with information light and recording reference light, and irradiates the holographic recording medium 20 with reproduction reference light. A pickup 31 for detecting reproduction light and reproducing information recorded on the holographic recording medium 20, and a drive device 84 that enables the pickup 31 to move in the radial direction of the holographic recording medium 20. I have.

  The optical recording / reproducing apparatus 100 uses a detection circuit 85 for detecting a focus error signal FE, a tracking error signal TE, and a reproduction signal RF from an output signal of the pickup 31, and a focus error signal FE detected by the detection circuit 85. Based on this, the actuator in the pickup 31 is driven to move the objective lens (not shown) in the thickness direction of the holographic recording medium 20 to perform focus servo, and the tracking error detected by the detection circuit 85. Based on the signal TE, an actuator in the pickup 31 is driven to move the objective lens in the radial direction of the holographic recording medium 20 to perform tracking servo, a tracking error signal TE and a controller to be described later. It controls the drive unit 84 based on a command from over La and a slide servo circuit 88 for performing a slide servo for moving the pickup 31 in the radial direction of the holographic recording medium 20.

  The optical recording / reproducing apparatus 100 further decodes the output data of the CMOS or CCD array in the pickup 31 to reproduce the data recorded in the data area of the holographic recording medium 20 or the reproduction signal from the detection circuit 85. A signal processing circuit 89 that reproduces a basic clock from RF and discriminates an address; a controller 90 that controls the entire optical recording / reproducing apparatus 100; and an operation unit 91 that gives various instructions to the controller 90. I have. The controller 90 inputs the basic clock and address information output from the signal processing circuit 89, and controls the pickup 31, spindle servo circuit 83, slide servo circuit 88, and the like. The spindle servo circuit 83 receives the basic clock output from the signal processing circuit 89. The controller 90 includes a CPU (Central Processing Unit), a ROM (Read Only Memory), and a RAM (Random Access Memory), and the CPU executes a program stored in the ROM using the RAM as a work area. The function of the controller 90 can be realized.

  Hereinafter, the present invention will be further described based on examples. However, this invention is not limited to the aspect shown in the Example.

Example 1
-Preparation of composition for holographic recording-
6.4 g of hexamethylene diisocyanate (Mitsui Chemical Polyurethane Co., Ltd., trade name: Takenate T-700), 5.21 g of polypropylene oxide triol (Mitsui Chemical Polyurethane Co., Ltd., trade name MN-300), polyethylene glycol (Tokyo) 4.64 g, manufactured by Kasei Kogyo Co., Ltd., 1.85 g of exemplary compound M-1, photopolymerization initiator (ethyl ester of 2,4,6-trimethylbenzoylphenylphosphinic acid, trade name Lucillin TPO-L, manufactured by BASF Japan Ltd.) ) 0.16 g and 0.20 g of a cured amine catalyst (manufactured by San Apro Co., Ltd., trade name: U-CAT 410) were mixed under a nitrogen stream to prepare a holographic recording composition.

(Example 2)
-Preparation of composition for holographic recording-
In Example 1, a holographic recording composition was prepared in the same manner as in Example 1 except that the exemplified compound M-6 was used instead of the exemplified compound M-1.

(Example 3)
-Preparation of composition for holographic recording-
In Example 1, a holographic recording composition was prepared in the same manner as in Example 1 except that Example Compound M-11 was used instead of Example Compound M-1.

Example 4
-Preparation of composition for holographic recording-
In Example 1, a holographic recording composition was prepared in the same manner as in Example 1 except that the exemplified compound M-19 was used instead of the exemplified compound M-1.

(Example 5)
-Preparation of composition for holographic recording-
In Example 1, a holographic recording composition was prepared in the same manner as in Example 1 except that the exemplified compound M-21 was used instead of the exemplified compound M-1.

(Comparative Example 1)
-Preparation of composition for holographic recording-
6.4 g of hexamethylene diisocyanate (Mitsui Chemical Polyurethane Co., Ltd., trade name: Takenate T-700), 5.21 g of polypropylene oxide triol (Mitsui Chemical Polyurethane Co., Ltd., trade name MN-300), polyethylene glycol (Tokyo) Kasei Kogyo Co., Ltd.) 4.64 g, 2,4,6-tribromophenyl acrylate (Daiichi Kogyo Seiyaku Co., Ltd., trade name: BR-30) 1.85 g, photopolymerization initiator (2, 4 , 6-Trimethylbenzoylphenylphosphinic acid ethyl ester, 0.16 g of trade name Lucillin TPO-L, manufactured by BASF Japan Ltd.) The composition for holographic recording was prepared by mixing under a nitrogen stream.

(Comparative Example 2)
-Preparation of composition for holographic recording-
A holographic recording composition was prepared in the same manner as in Comparative Example 1 except that the following Exemplified Compound R was used instead of 2,4,6-tribromophenyl acrylate in Comparative Example 1.

(Examples 6 to 10 and Comparative Examples 3 and 4)
-Production of optical recording media-
An antireflection treatment was performed on one surface of 0.5 mm thick glass so that the reflectance by incident light perpendicular to the wavelength of 405 nm was 0.1%, and a first substrate was produced.
An aluminum vapor deposition process was performed on one surface of 0.5 mm thick glass so that the reflectance by incident light perpendicular to the wavelength of 405 nm was 90%, and a second substrate was produced.
Next, a transparent polyethylene terephthalate sheet having a thickness of 500 μm was provided as a spacer on the surface of the first substrate not subjected to the antireflection treatment.
Next, the holographic recording compositions of Examples 1 to 5 and Comparative Examples 1 and 2 were each placed on the first substrate, and the aluminum-deposited surface of the second substrate was aired on the holographic recording composition. The first substrate and the second substrate were bonded to each other through a spacer so as not to get caught. Thereafter, the optical recording media of Examples 6 to 10 and Comparative Examples 3 and 4 were prepared by allowing to stand at 80 ° C. for 6 hours. The thickness of the formed recording layer was 200 μm.

<Recording on optical recording media and evaluation>
Using the collinear hologram recording / reproduction tester (B-VRD, manufactured by Pulse Tech Industrial Co., Ltd.), a series of multiple holograms were written on each of the produced optical recording media with a recording spot diameter of 200 μm at the focal position of the recording hologram. Thus, sensitivity (recording energy) and volumetric shrinkage of the medium were measured. The results are shown in Table 1.

-Measurement of sensitivity-
The irradiation light energy (mJ / cm ² ) at the time of recording was changed, and the change in the error probability (BER: Bit Error Rate) of the reproduction signal was measured. Usually, the luminance of the reproduction signal increases with the increase of irradiation light energy, and the BER of the reproduction signal tends to gradually decrease. Here, the lowest irradiation light energy at which a substantially good reproduced image (BER <10 ⁻³ ) can be obtained is defined as the recording sensitivity of the optical recording medium. The wavelength of recording light and reference light was 405 nm, and the wavelength of reproduction light was 405 nm.

-Volumetric shrinkage of medium-
As a means for analyzing the shrinkage and expansion of a photopolymer, a method of calculating from changes in interference fringes due to plane wave two-beam interference is known. In the FPR (Fringe Plane Rotation) model, the shrinkage of the recording layer occurred between recording and playback due to the difference between the recording angle of the Bragg grating recorded obliquely on the recording medium and the optimum playback angle after recording (or after fixing). Can be evaluated. FIG. 5 shows a conceptual diagram of this model. It is assumed that the shrinkage change that occurs before and after recording is only in the thickness direction.
The change in the inclination of the interference fringes by the FPR model is expressed by the following equation.
Φ ^* = Φ + ΔΦ = arctan [tan Φ / (1-α)] (1)
Here, Φ and Φ ^* are inclinations of interference fringes during recording and reproduction, respectively, and α is a change rate of the recording layer.
An interference fringe (6 mmφ) with a weak diffraction efficiency (˜1%) is recorded on a recording medium at a predetermined angle Φ by a 405 nm laser plane wave two-beam interferometer, and then exposure or fixing light irradiation of a recording medium (365 nm laser, spot diameter) 10 mmφ), the photoreactive component of the recording medium was completely consumed, the reproduction angle dependency of the diffraction efficiency was measured, and the angle of the interference fringes was measured again. The shrinkage rate α of the recording medium was estimated based on the formula (1) based on the change in the interference fringe inclination angle during recording and after exposure or fixing.

  From the results of Table 1, the optical recording media of Examples 6 to 10 using the holographic recording compositions of Examples 1 to 5 are Comparative Example 3 using the holographic recording compositions of Comparative Examples 1 and 2. Compared with the optical recording medium of No. 4, all have excellent recording sensitivity and small volume shrinkage.

  Since the optical recording composition of the present invention can perform higher density recording, it is suitable for production of various volume hologram type optical recording media capable of high density image recording.

It is a schematic sectional drawing which shows an example of the holographic recording medium concerning 1st embodiment. It is a schematic sectional drawing which shows an example of the holographic recording medium concerning 2nd embodiment. It is explanatory drawing which shows an example of the optical system which can be used for recording and reproduction | regeneration of the information to a holographic recording medium. It is a block diagram showing an example of the whole structure of the recording / reproducing apparatus used suitably for the recording and reproduction | regeneration of the information to the holographic recording medium of this invention. The conceptual diagram of a FPR model is shown.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Lower substrate 2 Reflective film 3 Servo pit pattern 4 Recording layer 5 Upper substrate 6 Filter layer 7 Second gap layer 8 First gap layer 12 Objective lens 13 Dichroic mirror 14 Detector 15 1/4 wavelength plate 16 Polarizing plate 17 Half Mirror 20 Holographic recording medium 21 Holographic recording medium 22 Holographic recording medium 31 Pickup 81 Spindle 82 Spindle motor 83 Spindle servo circuit 84 Drive device 85 Detection circuit 86 Focus servo circuit 87 Tracking servo circuit 88 Slide servo circuit 89 Signal processing circuit 90 Controller 91 Operation unit 100 Optical recording / reproducing device A Input / output surface FE Focus error signal TE Tracking error signal RF reproduction signal

Claims (12)

An optical recording compound which is a vinyl thiirane compound represented by the following general formula (I).
[In General Formula (I), R ¹ , R ² , R ³ and R ⁴ each independently represents a hydrogen atom or a substituent. ] In general formula (I), R ¹ represents a hydrogen atom, an alkyl group, an aryl group, an alkoxy group, a heterocyclic group or a halogen group, and R ² , R ³ and R ⁴ each independently represents a hydrogen atom, an alkyl group, The optical recording compound according to claim 1, which represents an aryl group or a heterocyclic group. In the general formula (I), R ¹ represents a hydrogen atom, an alkyl group or an aryl group, and R ² , R ³ and R ⁴ each independently represent a hydrogen atom, an alkyl group, an aryl group or a heterocyclic group. 2. The optical recording compound according to 1. 2. In general formula (I), R < ¹ > represents a hydrogen atom or an aryl group, R < ² >, R < ³ > and R < ⁴ > represent a hydrogen atom, an alkyl group, an aryl group, or a heterocyclic group each independently. Compound for optical recording. In general formula (I), R ¹ represents a hydrogen atom, R ² and R ³ each independently represents a hydrogen atom, an alkyl group, an aryl group or a heterocyclic group, and R ⁴ represents a hydrogen atom. The compound for optical recording described in 1. An optical recording composition comprising the optical recording compound according to claim 1. The optical recording composition according to claim 6, further comprising a thermosetting compound. The optical recording composition according to claim 7, wherein the thermosetting compound contains a polyfunctional isocyanate and a polyfunctional alcohol. The composition for optical recording according to any one of claims 6 to 8, further comprising a radical photopolymerization initiator. The optical recording composition according to claim 6, which is a holographic recording composition. The holographic recording medium which has a recording layer containing the compound for optical recording of any one of Claims 1-5. The holographic recording medium according to claim 11, wherein the recording layer is a recording layer formed from the optical recording composition according to claim 6.