JP2007279585A - Photosensitive composition, optical recording medium, optical recording method, and optical recording apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a photosensitive composition which is used to form recording layers for recording information by holography, less distorting the refractivity images by volume shrinkages following polymerization when recording information, and excellent in shelf life, and also provide an optical recording medium, an optical recording method, and an optical recording apparatus sufficiently sensitive with multiplexing properties. <P>SOLUTION: This photosensitive composition contains a polymerizing compound of a single function, a polymerizing compound of four or more functions, a polymerization initiator, and a polymer matrix. The polymerizing machine of the above polymerizing compound of a single function and the polymerizing machine of the above polymerizing compound of four or more functions are copolymerizable with each other. The content of the above polymerizing compound of four or more functions is a 1-50 mass section to the 100 mass section of the above polymerizing compound of a single function. This photosensitive composition is used to form recording layers to record information by holography. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a photosensitive composition used for forming a recording layer for recording information using holography, and an optical recording medium, an optical recording method, and an optical recording apparatus using the photosensitive composition.

  An optical recording medium is one of recording media capable of writing a large amount of information such as high-density image data. As this optical recording medium, for example, a rewritable optical recording medium such as a magneto-optical disk and a phase change optical disk and a write-once optical recording medium such as a CD-R have already been put into practical use. The demand for larger capacity is increasing. However, all conventionally proposed optical recording media are two-dimensional recording, and there is a limit to increasing the recording capacity. Therefore, recently, a hologram type optical recording medium capable of recording information three-dimensionally has attracted attention.

In the hologram type optical recording method, in general, information light given a two-dimensional intensity distribution and reference light having a substantially constant intensity are superposed inside a photosensitive recording layer to form them. Information is recorded by generating a distribution of optical characteristics inside the recording layer using interference fringes. On the other hand, in reading (reproducing) written information, the recording layer is irradiated with only the reference light in the same arrangement as in recording, and the reproducing light having an intensity distribution corresponding to the optical characteristic distribution formed inside the recording layer is used. This is done by emitting from the recording layer.
In this hologram type optical recording method, since the optical characteristic distribution is three-dimensionally formed in the recording layer, an area where information is written by one information light, an area where information is written by other information light, and Can be partially overlapped, that is, multiple recording is possible. When digital volume holography is used, the signal-to-noise ratio (S / N ratio) of one spot is extremely high, so the original information can be faithfully reproduced even if the S / N ratio is somewhat lowered by overwriting. . As a result, the number of times of multiple recording reaches several hundreds, and the recording capacity of the optical recording medium can be remarkably increased (see Patent Document 1).

  Examples of the optical recording medium include an optical recording medium 20 in which a recording layer 4 is laminated between substrates 10 and 11 as shown in FIG. In addition, as shown in FIG. 2, the optical axis of the information light and the optical axis of the reference light are coaxial, and the information light and the reference light are used for recording and recording. Examples thereof include an optical recording medium 21 in which a substrate 1, a first gap layer 8, a filter layer 6, a second gap layer 7, a recording layer 4, and a second substrate 5 are laminated in this order. As an index indicating the number of times of multiple recording on the recording layer in such an optical recording medium, a dynamic range indicating “how many holograms having a certain diffraction efficiency can be multiplexed” is used. Specifically, a value obtained by adding the square root of the diffraction efficiency of each multiplexed hologram to all the holograms is used as the dynamic range. Examples of the method for increasing the dynamic range include improvement of recording layer formation, improvement of the composition of the recording layer, improvement of the recording method, and the like. As a method for improving the recording layer formation, a method is generally used in which the recording layer is multilayered to increase the thickness and improve the dynamic range. However, there is a problem in that as the number of multilayers increases, unevenness in thickness and production efficiency decrease.

Further, in order to produce a holographic recording medium capable of forming a photosensitive layer with a high thickness and without rapid and high-temperature heating, for example, a material containing an NCO-terminated prepolymer and a polyol, a photoreactive material, An optical product containing the above polymerized product has been proposed (see Patent Document 2). However, with this proposal, it is possible to produce a thick multi-volume holographic recording medium, but after recording information, the intensity of the read signal gradually attenuates and is not suitable for semi-permanent storage. .
For this reason, attempts have been made to improve the storage stability of images by using a polyfunctional monomer having a large molecular weight. However, in this method, volume shrinkage due to monomer polymerization at the time of information recording was large and formed. The refractive index image is destroyed and high-density multiple information recording is difficult.

  Therefore, a photosensitive composition suitable for volume holographic applications having excellent storage stability without destroying the refractive index image formed in the photosensitive layer made of the photosensitive composition due to volume shrinkage accompanying polymerization during information recording. The present situation is that it is desired to quickly provide an optical recording medium, an optical recording method, and an optical recording apparatus having a recording layer made of the photosensitive composition.

JP 2002-123949 A JP 2004-537620 A

  An object of the present invention is to solve the conventional problems and achieve the following objects. That is, the present invention is a photosensitive composition used for forming a recording layer in which information is recorded using holography, which is free from collapse of a refractive index image due to volume shrinkage caused by polymerization during information recording, has excellent storage stability. It is another object of the present invention to provide an optical recording medium, an optical recording method, and an optical recording apparatus having sufficient sensitivity and multiple characteristics.

Means for solving the problems are as follows. That is,
<1> a monofunctional polymerizable compound, a tetrafunctional or higher polymerizable compound, a polymerization initiator, and a polymer matrix;
The polymerizable group of the monofunctional polymerizable compound and the polymerizable group of the tetrafunctional or higher polymerizable compound can be copolymerized with each other, and the content of the tetrafunctional or higher polymerizable compound is the monofunctional polymerizable compound. It is 1-50 mass parts with respect to 100 mass parts of functional polymerizable compounds, It is used for formation of the recording layer which records information using holography, It is a photosensitive composition characterized by the above-mentioned.
<2> The photosensitive composition according to <1>, wherein the tetrafunctional or higher polymerizable compound has a molecular weight of 500 or more.
<3> Any one of <1> to <2>, wherein the total content of the monofunctional polymerizable compound and the tetrafunctional or higher polymerizable compound in the total solid content of the photosensitive composition is 1 to 40% by mass. It is a photosensitive composition as described in above.
<4> The photosensitive composition according to any one of <1> to <3>, wherein the content of the polymerization initiator in the total solid content of the photosensitive composition is 0.1 to 10% by mass.
<5> The photosensitive composition according to any one of <1> to <4>, wherein the content of the polymer matrix in the total solid content of the photosensitive composition is 60 to 99% by mass.
<6> An optical recording medium comprising the photosensitive composition according to any one of <1> to <5> and having a recording layer for recording information using holography.
<7> The optical recording medium according to <6>, including at least a first substrate, a selective reflection layer, a recording layer, and a second substrate in this order.
<8> The optical recording medium according to <7>, wherein the selective reflection layer transmits the first light and reflects the second light.
<9> The optical recording medium according to any one of <7> to <8>, wherein the selective reflection layer is at least one of a dichroic mirror layer, a color material-containing layer, a dielectric vapor deposition layer, and a cholesteric liquid crystal layer. is there.
<10> The optical recording medium according to any one of <8> to <9>, wherein the wavelength of the first light is 350 to 600 nm and the wavelength of the second light is 600 to 900 nm.
_{<11> λ 0 ~λ 0 /} cos20 ° ( However, lambda ₀ represents a wavelength of the irradiated light) The optical recording medium according to any one of the light reflectance is 40% or more in the <8> of the <10> It is.
_{<12> λ 0 ~λ 0 /} cos40 ° ( However, lambda ₀ represents a wavelength of the irradiated light) The optical recording medium according to any one of the light reflectance is 40% or more in the <8> of the <11> It is.
<13> The optical recording medium according to any one of <7> to <12>, wherein the substrate has a servo pit pattern.
<14> The optical recording medium according to <13>, wherein the servo pit pattern has a reflective film on the surface.
<15> The optical recording medium according to <14>, wherein the reflective film is a metal reflective film.

<16> When the optical recording medium according to any one of <6> to <15> is irradiated with information light and reference light, the optical axis of the information light and the optical axis of the reference light are coaxial. The optical recording method is characterized in that information is recorded on the recording layer by an interference pattern generated by interference between the information light and the reference light.
<17> An optical reproducing method, wherein the recorded information is reproduced by irradiating the interference pattern recorded on the recording layer with the reference light by the optical recording method according to <16>.
<18> The optical reproduction method according to <17>, wherein the reference light is irradiated to the interference pattern at the same angle as the reference light used for recording on the optical recording medium to reproduce the recorded information.
<19> The information light and the optical information recording medium according to any one of <6> to <15>, wherein the optical axis of coherent information light and the optical axis of reference light are coaxial. A light irradiating means for irradiating a reference light; and an interference image recording means for forming an interference image by interference between the information light and the reference light and recording the interference image on the optical recording medium. An optical recording device.

The photosensitive composition of the present invention comprises a monofunctional polymerizable compound, a tetrafunctional or higher functional polymerizable compound, a polymerization initiator, and a polymer matrix,
The polymerizable group of the monofunctional polymerizable compound and the polymerizable group of the tetrafunctional or higher polymerizable compound can be copolymerized with each other, and the content of the tetrafunctional or higher polymerizable compound is the monofunctional polymerizable compound. 1 to 50 parts by mass with respect to 100 parts by mass of the functional polymerizable compound,
It is used to form a recording layer for recording information using holography.
In the photosensitive composition of the present invention, there is no collapse of the refractive index image due to volume shrinkage accompanying polymerization at the time of information recording, excellent storage stability, and suitable for forming a recording layer for recording information using holography. Used.

  The optical recording medium of the present invention is composed of the photosensitive composition of the present invention and has at least a recording layer for recording information using holography. Therefore, the optical recording medium has excellent sensitivity, multiple characteristics, and storability of recorded information. It is suitable for holographic applications.

  The optical recording method of the present invention irradiates the optical recording medium of the present invention with information light and reference light so that the optical axis of the information light and the optical axis of the reference light are coaxial, Information is recorded on the recording layer by an interference pattern generated by interference between the information light and the reference light. In the optical recording method of the present invention, by using the optical recording medium of the present invention, information is recorded on the recording layer by an interference pattern due to interference between the information light and the reference light, so that both signal intensity and multiplexing performance are compatible. Therefore, it is possible to realize unprecedented high density recording.

The optical reproduction method of the present invention reproduces information by irradiating the interference pattern recorded on the recording layer by the reference light with the optical recording method of the present invention.
In the optical reproducing method of the present invention, the interference pattern recorded on the recording layer by the optical recording method of the present invention can be read efficiently and accurately to reproduce high-density recorded information.

  The optical recording apparatus of the present invention irradiates the optical recording medium of the present invention with the information light and the reference light so that the optical axis of coherent information light and the optical axis of the reference light are coaxial. Light irradiation means, and interference image recording means for forming an interference image due to interference between the information light and the reference light and recording the interference image on the optical recording medium. In the optical recording apparatus of the present invention, since the optical recording medium of the present invention is used, both signal intensity and multiplexing performance can be achieved, and optical recording capable of high sensitivity and high multiplexing recording can be performed.

  According to the present invention, conventional problems can be solved, the refractive index image does not collapse due to volume shrinkage accompanying polymerization during information recording, the storage stability is excellent, and a recording layer for recording information using holography is formed. And an optical recording medium, an optical recording method, and an optical recording apparatus having sufficient sensitivity and multiple characteristics can be provided.

(Photosensitive composition)
The photosensitive composition of the present invention is used for forming a recording layer for recording information using holography, and is a monofunctional polymerizable compound, a tetrafunctional or higher functional polymerizable compound, a polymerization initiator, and a polymer matrix. And further contains other components as necessary.

The polymerizable group of the monofunctional polymerizable compound and the polymerizable group of the tetrafunctional or higher polymerizable compound can be copolymerized with each other.
Here, as a method for determining whether or not the polymerizable group of the monofunctional polymerizable compound and the polymerizable group of the tetrafunctional or higher polymerizable compound can be copolymerized with each other, in any solution It is possible to determine whether or not a polymer obtained by mixing a plurality of target polymerizable compounds and polymerizing them by an arbitrary polymerization initiation reaction has become a copolymer. In this determination, porous gel column chromatography, mass spectrometry, or the like is used as a compound identification method.

-Monofunctional polymerizable compound-
The monofunctional polymerizable compound is not particularly limited as long as it has one polymerizable group in the molecule and can be appropriately selected according to the purpose. For example, (meth) acrylic acid esters, croton Acid esters, vinyl esters, maleic acid diesters, fumaric acid diesters, itaconic acid diesters, (meth) acrylamides, vinyl ethers, esters of vinyl alcohol, styrenes (eg, styrene, styrene derivatives, etc.), (Meth) acrylonitrile, heterocyclic group substituted with vinyl group (for example, vinylpyridine, vinylpyrrolidone, vinylcarbazole, etc.), N-vinylformamide, N-vinylacetamide, N-vinylimidazole, vinylcaprolactone, 2-acrylamide- 2-methylpropanesulfonic acid, phosphoric acid Vinyl monomer having (2-acryloyloxyethyl ester), mono (1-methyl-2-acryloyloxyethyl ester) phosphate, and functional group (for example, urethane group, urea group, sulfonamide group, phenol group, imide group) Etc. These may be used individually by 1 type and may use 2 or more types together.

  Examples of the (meth) acrylic acid esters include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, and isobutyl (meth) ) Acrylate, t-butyl (meth) acrylate, n-hexyl (meth) acrylate, cyclohexyl (meth) acrylate, t-butylcyclohexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, t-octyl (meth) acrylate, Dodecyl (meth) acrylate, octadecyl (meth) acrylate, acetoxyethyl (meth) acrylate, phenyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-methoxyethyl (meth) acrylate 2-ethoxyethyl (meth) acrylate, 2- (2-methoxyethoxy) ethyl (meth) acrylate, 3-phenoxy-2-hydroxypropyl (meth) acrylate, benzyl (meth) acrylate, diethylene glycol monomethyl ether (meta ) Acrylate, diethylene glycol monoethyl ether (meth) acrylate, diethylene glycol monophenyl ether (meth) acrylate, triethylene glycol monomethyl ether (meth) acrylate, triethylene glycol monoethyl ether (meth) acrylate, polyethylene glycol monomethyl ether (meth) acrylate , Polyethylene glycol monoethyl ether (meth) acrylate, β-phenoxyethoxyethyl acrylate, Nylphenoxypolyethylene glycol (meth) acrylate, dicyclopentanyl (meth) acrylate, dicyclopentenyl (meth) acrylate, dicyclopentenyloxyethyl (meth) acrylate, trifluoroethyl (meth) acrylate, octafluoropentyl (meth) Examples thereof include acrylate, perfluorooctylethyl (meth) acrylate, tribromophenyl (meth) acrylate, and tribromophenyloxyethyl (meth) acrylate.

Examples of the crotonic acid esters include butyl crotonate and hexyl crotonate.
Examples of the vinyl esters include vinyl acetate, vinyl propionate, vinyl butyrate, vinyl methoxyacetate, vinyl benzoate, vinyl methyl methylhexahydrophthalate, vinylethyl methylhexahydrophthalate, and vinylbutyl methylhexahydrophthalate. And vinyl hexyl methyl hexahydrophthalate, vinyl octyl terephthalate, vinyl ethyl terephthalate, vinyl hexyl terephthalate, vinyl octyl phthalate, vinyl hexyl phthalate, vinyl ethyl phthalate, and the like.

Examples of the maleic acid diesters include dimethyl maleate, diethyl maleate, and dibutyl maleate.
Examples of the fumaric acid diesters include dimethyl fumarate, diethyl fumarate, dibutyl fumarate and the like.
Examples of the itaconic acid diesters include dimethyl itaconate, diethyl itaconate, and dibutyl itaconate.

  Examples of the (meth) acrylamides include (meth) acrylamide, N-methyl (meth) acrylamide, N-ethyl (meth) acrylamide, N-propyl (meth) acrylamide, N-isopropyl (meth) acrylamide, N- n-butylacryl (meth) amide, Nt-butyl (meth) acrylamide, N-cyclohexyl (meth) acrylamide, N- (2-methoxyethyl) (meth) acrylamide, N, N-dimethyl (meth) acrylamide, N, N-diethyl (meth) acrylamide, N-phenyl (meth) acrylamide, N-benzyl (meth) acrylamide, (meth) acryloylmorpholine, diacetone acrylamide, N-dibromophenyl (meth) acrylamide, N-dibromophenyl- N-methyl (Meth) acrylamide, N- tribromophenyl (meth) acrylamide, N- dibromophenylene El -N- methyl (meth) acrylamide, such as N- dibromophenylene Roh carboxyethyl (meth) acrylamide.

  Examples of the styrenes include styrene, methyl styrene, dimethyl styrene, trimethyl styrene, ethyl styrene, isopropyl styrene, butyl styrene, hydroxy styrene, methoxy styrene, butoxy styrene, acetoxy styrene, chlorostyrene, dichlorostyrene, bromostyrene, chloro Methylstyrene, hydroxystyrene protected with a group deprotectable by an acidic substance (for example, t-Boc), methyl vinylbenzoate, α-methylstyrene, vinylnaphthalene, methylvinylnaphthalene, N, N-dimethylaminonaphthalene , Vinyl anthracene, divinylbenzene and the like.

  Examples of the vinyl ethers include methyl vinyl ether, butyl vinyl ether, hexyl vinyl ether, methoxyethyl vinyl ether, and compounds obtained by substituting a vinyloxy group for the (meth) acryloyloxy group in the compound described as the (meth) acrylate.

-4 or higher functional polymerizable compounds
The tetrafunctional or higher polymerizable compound preferably has 4 or more polymerizable groups in the molecule, and preferably has 4 to 8 ranges, and can be copolymerized with the monofunctional polymerizable compound. . If the number of polymerizable groups is less than 4, the recorded image storability, which is the object and effect of the present invention, may not be sufficiently obtained. On the other hand, when the number of the polymerizable groups exceeds 8, it may be difficult to obtain and produce the compound and to introduce it into the composition.
Such a tetrafunctional or higher functional polymerizable compound can be appropriately selected according to the monofunctional polymerizable compound to be used. For example, when an acrylic ester is used as the monofunctional polymerizable compound, Polyurethane obtained by reacting pentaerythritol, dipentaerythritol, ditrimethylolpropane, or polyethylene glycol of these compounds, polypropylene glycol, acrylic ester of tetramethylene glycol modified polyol, polyisocyanate, polyester polyol and the above polyfunctional alcohols Examples thereof include acrylic acid esters having 4 or more substitutions of polyol and polyester polyol. These may be used individually by 1 type and may use 2 or more types together.

  Further, when methacrylic acid, itaconic acid, crotonic acid, maleic acid, or fumaric acid ester is used as a monofunctional polymerizable compound, an ester having four or more substitutions with the polyols, polyurethane polyols, and polyester polyols. Compounds can be used. Further, since (meth) acrylic acid, itaconic acid, crotonic acid, maleic acid, or fumaric acid esters can be copolymerized, a monofunctional polymerizable compound and a polyfunctional polymerizable compound can be optionally combined with these combinations. It is possible to use together.

  When the (meth) acrylamide is used as a monofunctional polymerizable compound, for example, (meth) acrylic acid, triethylenetetramine, tetraethylenepentamine, various tetrafunctional or higher polyamines useful as an epoxy curing agent, Furthermore, oxalic acid, succinic acid, fumaric acid, adipic acid, other terminal alkylene dicarboxylic acids, or alkyl-substituted derivatives thereof, phthalic acid, terephthalic acid, isophthalic acid, trimellitic acid, pyromellitic acid, naphthalenetetracarboxylic acid An amide compound with a polyamide polyamine derived from the reaction of a bifunctional or higher carboxylic acid such as an acid with the above polyamines or a tetrafunctional or higher functional polyamide polyamine useful as an epoxy curing agent can be used.

When the styrene is used as a monofunctional polymerizable compound, a compound in which styrene or naphthalene is derived and a plurality of styrene derivatives or naphthalene derivatives are connected via the polyol or polyamide can be used.
When the vinyl ether compound is used as a monofunctional polymerizable compound, a tetra- or higher functional polyvinyl ether compound derived from the polyol compound can be used.

The molecular weight of the tetrafunctional or higher polymerizable compound is preferably 500 or more, more preferably 600 or more, and still more preferably 700 to 3,000. If the molecular weight is less than 500, the effect of drastically improving the storage stability of the target recorded image over time may not be obtained sufficiently.
Here, the molecular weight can be measured by, for example, porous gel column chromatography or mass spectrometry.

  In addition to the monofunctional polymerizable compound and the tetrafunctional or higher functional polymerizable compound, the photosensitive composition of the present invention may further include a bifunctional polymerizable compound, a trifunctional polymerizable compound, or the like as necessary. The polymerizable compound can also be contained.

The content of the tetrafunctional or higher functional polymerizable compound is 1 to 50 parts by mass, preferably 1 to 30 parts by mass, and more preferably 2 to 20 parts by mass with respect to 100 parts by mass of the monofunctional polymerizable compound. 5-10 mass parts is still more preferable. Within this range, it is possible to obtain a photosensitive composition that is excellent in storage stability of recorded information and that does not cause refractive index collapse during multiple recording. If the content is less than 1 part by mass, the preservability of recorded information may not be improved. If it exceeds 50 parts by mass, the refractive index image carrying previously written information is destroyed during multiple recording. Reading may be impossible.
Here, “storability” is defined as the storability of recorded information unless otherwise specified. In addition, “the recorded information has good storage stability” means that the recorded information can be reproduced without deterioration.

  1-40 mass% is preferable with respect to the total solid of the said photosensitive composition, and, as for the total content of the said monofunctional polymeric compound and tetrafunctional or more polymeric compound, 2-30 mass% is more preferable, 3-25 mass% is still more preferable. Within this range, a photosensitive composition excellent in sensitivity, multiple characteristics, and storage stability of recorded information can be obtained. If the content is less than 1% by mass, sufficient sensitivity and multiple characteristics may not be obtained for volume holographic applications. If the content exceeds 40% by mass, the storage stability of recorded information deteriorates, and resolution is increased. May worsen and cause recording problems.

-Polymerization initiator-
The polymerization initiator is not particularly limited, and various known systems can be used. The initiator system may be a system composed of a single compound or a system composed of a plurality of compounds. As the initiator system, a system that activates radical polymerization and a system that activates cationic polymerization or ring-opening polymerization may be performed in a single initiator system, or each in two different initiator systems. May be.

  The photocationic polymerization initiator or ring-opening polymerization initiator is preferably a photoacid generator. Examples of the photoacid generator include trichloromethyl-s-triazines, diaryliodonium salts, triarylsulfonium salts, And tetraammonium salts and sulfonic acid esters.

  Examples of the trichloromethyl-s-triazines include 2,4,6-tris (trichloromethyl) -s-triazine, 2-phenyl-4,6-bis (trichloromethyl) -s-triazine, 2- ( 4-chlorophenyl) -4,6-bis (trichloromethyl) -s-triazine, 2- (3-chlorophenyl) -4,6-bis (trichloromethyl) -s-triazine, 2- (2-chlorophenyl) -4 , 6-Bis (trichloromethyl) -s-triazine, 2- (4-methoxyphenyl) -4,6-bis (trichloromethyl) -s-triazine, 2- (3-methoxyphenyl) -4,6-bis (Trichloromethyl) -s-triazine, 2- (2-methoxyphenyl) -4,6-bis (trichloromethyl) -s-triazine, 2- (4-methyl) Ophenyl) -4,6-bis (trichloromethyl) -s-triazine, 2- (3-methylthiophenyl) -4,6-bis (trichloromethyl) -s-triazine, 2- (2-methylthiophenyl) -4 , 6-Bis (trichloromethyl) -s-triazine, 2- (4-methoxynaphthyl) -4,6-bis (trichloromethyl) -s-triazine, 2- (3-methoxynaphthyl) -4,6-bis (Trichloromethyl) -s-triazine, 2- (2-methoxynaphthyl) -4,6-bis (trichloromethyl) -s-triazine, 2- (4-methoxy-β-styryl) -4,6-bis ( Trichloromethyl) -s-triazine, 2- (3-methoxy-β-styryl) -4,6-bis (trichloromethyl) -s-triazine, 2- (2-methoxy-β-sulfane) Ryl) -4,6-bis (trichloromethyl) -s-triazine, 2- (3,4,5-trimethoxy-β-styryl) -4,6-bis (trichloromethyl) -s-triazine, 2- ( 4-methylthio-β-styryl) -4,6-bis (trichloromethyl) -s-triazine, 2- (3-methylthio-β-styryl) -4,6-bis (trichloromethyl) -s-triazine, 2 -(3-methylthio-β-styryl) -4,6-bis (trichloromethyl) -s-triazine, 2-piperonyl-4,6-bis (trichloromethyl) -s-triazine, 2- [2- (furan -2-yl) ethenyl] -4,6-bis (trichloromethyl) -s-triazine, 2- [2- (5-methylfuran-2-yl) ethenyl] -4,6-bis (trichloromethyl)- s- Triazine, 2- [2- (4-diethylamino-2-methylphenyl) ethenyl] -4,6-bis (trichloromethyl) -s-triazine, and the like.

  Examples of the diaryliodonium salts include diphenyliodonium tetrafluoroborate, diphenyliodonium hexafluorophosphonate, diphenyliodonium hexafluoroarsenate, diphenyliodonium trifluoromethanesulfonate, diphenyliodonium trifluoroacetate, diphenyliodonium-p-toluenesulfonate, Diphenyliodonium butyltris (2,6-difluorophenyl) borate, diphenyliodonium hexyltris (p-chlorophenyl) borate, diphenyliodonium hexyltris (3-trifluoromethylphenyl) borate, 4-methoxyphenylphenyliodoniumtetrafluoroborate, 4 -Methoxyphenylphenyl iodoni Hexafluorophosphonate, 4-methoxyphenylphenyliodonium hexafluoroarsenate, 4-methoxyphenylphenyliodonium trifluoromethanesulfonate, 4-methoxyphenylphenyliodonium trifluoroacetate, 4-methoxyphenylphenyliodonium-p-toluenesulfonate, 4-methoxyphenylphenyliodonium butyltris (2,6-difluorophenyl) borate, 4-methoxyphenylphenyliodonium hexyltris (p-chlorophenyl) borate, 4-methoxyphenylphenyliodonium hexyltris (3-trifluoromethylphenyl) borate Bis (4-tert-butylphenyl) iodonium tetrafluoroborate, bis (4-te t-butylphenyl) iodonium hexafluoroarsenate, bis (4-tert-butylphenyl) iodonium trifluoromethanesulfonate, bis (4-tert-butylphenyl) iodonium trifluoroacetate, bis (4-tert-butylphenyl) iodonium -P-toluenesulfonate, bis (4-tert-butylphenyl) iodonium butyltris (2,6-difluorophenyl) borate, bis (4-tert-butylphenyl) iodonium hexyltris (p-chlorophenyl) borate, bis ( 4-tert-butylphenyl) iodonium hexyltris (3-trifluoromethylphenyl) borate and the like.

  Examples of the triarylsulfonium salts include triphenylsulfonium tetrafluoroborate, triphenylsulfonium hexafluorophosphonate, triphenylsulfonium hexafluoroarsenate, triphenylsulfonium trifluoromethanesulfonate, triphenylsulfonium trifluoroacetate, triphenylsulfonium. -P-toluenesulfonate, triphenylsulfonium butyltris (2,6-difluorophenyl) borate, triphenylsulfonium hexyltris (p-chlorophenyl) borate, triphenylsulfonium hexyltris (3-trifluoromethylphenyl) borate, 4 -Methoxyphenyldiphenylsulfonium tetrafluoroborate, 4-methoxyphenyl Nyldiphenylsulfonium hexafluorophosphonate, 4-methoxyphenyldiphenylsulfonium hexafluoroarsenate, 4-methoxyphenyldiphenylsulfonium trifluoromethanesulfonate, 4-methoxyphenyldiphenylsulfonium trifluoroacetate, 4-methoxyphenyldiphenylsulfonium-p-toluenesulfo Narate, 4-methoxyphenyldiphenylsulfonium butyltris (2,6-difluorophenyl) borate, 4-methoxyphenyldiphenylsulfonium hexyltris (p-chlorophenyl) borate, 4-methoxyphenyldiphenylsulfonium hexyltris (3-trifluoromethylphenyl) ) Borate, 4-phenylthiophenyldiphenylsulfonium Rafluoroborate, 4-phenylthiophenyldiphenylsulfonium hexafluorophosphonate, 4-phenylthiophenyldiphenylsulfonium hexafluoroarsenate, 4-phenylthiophenyldiphenylsulfonium trifluoromethanesulfonate, 4-phenylthiophenyldiphenylsulfonium trifluoroacetate, 4-phenylthiophenyldiphenylsulfonium-p-toluenesulfonate, 4-phenylthiophenyldiphenylsulfonium butyltris (2,6-difluorophenyl) borate, 4-phenylthiophenyldiphenylsulfonium hexyltris (p-chlorophenyl) borate, 4 -Phenylthiophenyldiphenylsulfonium hexyltris (3-trifluoromethyl Enyl) borate, 4-hydroxy-1-naphthalenyl) dimethylsulfonium tetrafluoroborate, 4-hydroxy-1-naphthalenyl) dimethylsulfonium hexafluorophosphonate, 4-hydroxy-1-naphthalenyl) dimethylsulfonium hexafluoroarsenate, 4-hydroxy -1-naphthalenyl) dimethylsulfonium trifluoromethanesulfonate, 4-hydroxy-1-naphthalenyl) dimethylsulfonium trifluoroacetate, 4-hydroxy-1-naphthalenyl) dimethylsulfonium-p-toluenesulfonate, 4-hydroxy-1-naphthalenyl ) Dimethylsulfonium butyltris (2,6-difluorophenyl) borate, 4-hydroxy-1-naphthalenyl) dimethylsulfonium Kishirutorisu (p- chlorophenyl) borate, 4-hydroxy-1-naphthalenyl) dimethyl sulfonium hexyl tris (3-trifluoromethylphenyl) borate, and the like.

  Examples of the quaternary ammonium salts include tetramethylammonium tetrafluoroborate, tetramethylammonium hexafluorophosphonate, tetramethylammonium hexafluoroarsenate, tetramethylammonium trifluoromethanesulfonate, tetramethylammonium trifluoroacetate, tetramethylammonium. -P-toluenesulfonate, tetramethylammonium butyltris (2,6-difluorophenyl) borate, tetramethylammonium hexyltris (p-chlorophenyl) borate, tetramethylammonium hexyltris (3-trifluoromethylphenyl) borate, tetra Butylammonium tetrafluoroborate, tetrabutylammonium hexafluorophor Phonate, tetrabutylammonium hexafluoroarsenate, tetrabutylammonium trifluoromethanesulfonate, tetrabutylammonium trifluoroacetate, tetrabutylammonium-p-toluenesulfonate, tetrabutylammonium butyltris (2,6-difluorophenyl) borate, Tetrabutylammonium hexyltris (p-chlorophenyl) borate, tetrabutylammonium hexyltris (3-trifluoromethylphenyl) borate, benzyltrimethylammonium tetrafluoroborate, benzyltrimethylammonium hexafluorophosphonate, benzyltrimethylammonium hexafluoroarsenate, benzyl Trimethylammonium trifluoromethane Sulfonate, benzyltrimethylammonium trifluoroacetate, benzyltrimethylammonium-p-toluenesulfonate, benzyltrimethylammonium butyltris (2,6-difluorophenyl) borate, benzyltrimethylammonium hexyltris (p-chlorophenyl) borate, benzyltrimethylammonium hexyl Tris (3-trifluoromethylphenyl) borate, benzyldimethylphenylammonium tetrafluoroborate, benzyldimethylphenylammonium hexafluorophosphonate, benzyldimethylphenylammonium hexafluoroarsenate, benzyldimethylphenylammonium trifluoromethanesulfonate, benzyldimethylphenylammonium tris Fluoroacetate, benzyldimethylphenylammonium-p-toluenesulfonate, benzyldimethylphenylammonium butyltris (2,6-difluorophenyl) borate, benzyldimethylphenylammonium hexyltris (p-chlorophenyl) borate, benzyldimethylphenylammonium hexyltris ( 3-trifluoromethylphenyl) borate, N-cinnamylideneethylphenylammonium tetrafluoroborate, N-cinnamylideneethylphenylammonium hexafluorophosphonate, N-cinnamylideneethylphenylammonium hexafluoroarsenate, N-cinnamiri Denethylphenylammonium trifluoromethanesulfonate, N-cinnamylideneethylpheny Ammonium trifluoroacetate, N-cinnamylideneethylphenylammonium-p-toluenesulfonate, N-cinnamylideneethylphenylammonium butyltris (2,6-difluorophenyl) borate, N-cinnamylideneethylphenylammonium hexyltris (P-chlorophenyl) borate, N-cinnamylideneethylphenylammonium hexyltris (3-trifluoromethylphenyl) borate, and the like.

  Examples of the sulfonic acid esters include α-hydroxymethylbenzoin-p-toluenesulfonic acid ester, α-hydroxymethylbenzoin-trifluoromethanesulfonic acid ester, α-hydroxymethylbenzoin-methanesulfonic acid ester, pyrogallol-tri ( p-toluenesulfonic acid) ester, pyrogallol-tri (trifluoromethanesulfonic acid) ester, pyrogallol-trimethanesulfonic acid ester, 2,4-dinitrobenzyl-p-toluenesulfonic acid ester, 2,4-dinitrobenzyl-trifluoromethane Sulfonic acid ester, 2,4-dinitrobenzyl-methanesulfonic acid ester, 2,4-dinitrobenzyl-1,2-naphthoquinonediazide-5-sulfonic acid ester, 2,6-dinitrobenze -P-toluenesulfonic acid ester, 2,6-dinitrobenzyl-trifluoromethanesulfonic acid ester, 2,6-dinitrobenzyl-methanesulfonic acid ester, 2,6-dinitrobenzyl-1,2-naphthoquinonediazide-5-sulfone Acid ester, 2-nitrobenzyl-p-toluenesulfonate, 2-nitrobenzyl-trifluoromethanesulfonate, 2-nitrobenzyl-methanesulfonate, 2-nitrobenzyl-1,2-naphthoquinonediazide-5 Sulfonic acid ester, 4-nitrobenzyl-p-toluenesulfonic acid ester, 4-nitrobenzyl-trifluoromethanesulfonic acid ester, 4-nitrobenzyl-methanesulfonic acid ester, 4-nitrobenzyl-1,2-naphthoquinonediazide 5-sulfonic acid ester, N-hydroxynaphthalimide-p-toluenesulfonic acid ester, N-hydroxynaphthalimide-trifluoromethanesulfonic acid ester, N-hydroxynaphthalimide-methanesulfonic acid ester, N-hydroxy-5-norbornene- 2,3-dicarboximide-p-toluenesulfonic acid ester, N-hydroxy-5-norbornene-2,3-dicarboximide-trifluoromethanesulfonic acid ester, N-hydroxy-5-norbornene-2,3-di Carboximide-methanesulfonic acid ester, 2,4,6,3 ′, 4 ′, 5′-hexahydroxybenzophenone-1,2-naphthoquinonediazide-4-sulfonic acid ester, 1,1,1-tri (p- Hydroxyphenyl) ethane-1,2- And naphthoquinonediazide-4-sulfonic acid ester.

  Among these compounds, examples of trichloromethyl-s-triazines include 2- (3-chlorophenyl) -4,6-bis (trichloromethyl) -s-triazine and 2- (4-methoxyphenyl) -4. , 6-Bis (trichloromethyl) -s-triazine, 2- (4-methylthiophenyl) -4,6-bis (trichloromethyl) -s-triazine, 2- (4-methoxy-β-styryl) -4, 6-bis (trichloromethyl) -s-triazine, 2-piperonyl-4,6-bis (trichloromethyl) -s-triazine, 2- [2- (furan-2-yl) ethenyl] -4,6-bis (Trichloromethyl) -s-triazine, 2- [2- (5-methylfuran-2-yl) ethenyl] -4,6-bis (trichloromethyl) -s-triazine, 2- [ -(4-Diethylamino-2-methylphenyl) ethenyl] -4,6-bis (trichloromethyl) -s-triazine or 2- (4-methoxynaphthyl) -4,6-bis (trichloromethyl) -s-triazine Diphenyliodonium trifluoroacetate, diphenyliodonium trifluoromethanesulfonate, 4-methoxyphenylphenyliodonium trifluoromethanesulfonate or 4-methoxyphenylphenyliodonium trifluoroacetate as triaryliodonium salts; triphenylsulfonium salts as triarylsulfonium salts Sulfonium trifluoromethanesulfonate, triphenylsulfonium trifluoroacetate, 4-methoxyphenyldiphenylsulfonium trifluoromethanes Sulfonate, 4-methoxyphenyldiphenylsulfonium trifluoroacetate, 4-phenylthiophenyldiphenylsulfonium trifluoromethanesulfonate or 4-phenylthiophenyldiphenylsulfonium trifluoroacetate; quaternary ammonium salts include tetramethylammonium butyltris (2, 6-difluorophenyl) borate, tetramethylammonium hexyltris (p-chlorophenyl) borate, tetramethylammonium hexyltris (3-trifluoromethylphenyl) borate, benzyldimethylphenylammonium butyltris (2,6-difluorophenyl) borate, Benzyldimethylphenylammonium hexyltris (p-chlorophenyl) borate, benzyldi Tilphenylammonium hexyltris (3-trifluoromethylphenyl) borate; sulfonic acid esters include 2,6-dinitrobenzyl-p-toluenesulfonic acid ester, 2,6-dinitrobenzyl-trifluoromethanesulfonic acid ester, N -Hydroxynaphthalimide-p-toluenesulfonic acid ester, N-hydroxynaphthalimide-trifluoromethanesulfonic acid ester, and the like.

  Examples of the photo radical polymerization initiation system include organic halogenated compounds, carbonyl compounds, organic peroxide compounds, azo polymerization initiators, azide compounds, metallocene compounds, hexaarylbiimidazole compounds, organic boric acid compounds, disulfonic acid compounds. Oxime ester compounds, onium salt compounds, and the like.

  Specific examples of the organic halogenated compound include Wakabayashi et al., “Bull Chem. Soc Japan” 42, 2924 (1969), US Pat. No. 3,905,815, Japanese Patent Publication No. 46-4605, JP-A-48-36281, JP-A-55-32070, JP-A-60-239736, JP-A-61-169835, JP-A-61-169837, JP-A-62-2 58241, JP-A 62-212401, JP-A 63-70243, JP-A 63-298339, M.S. P. Examples include the compounds described in Hutt “Journal of Heterocyclic Chemistry” 1 (No 3), (1970) ”. Among these, an oxazole compound substituted with a trihalomethyl group and an S-triazine compound are particularly preferable.

  More preferably, an s-triazine derivative having at least one mono, di, or trihalogen-substituted methyl group bonded to the s-triazine ring, specifically, for example, 2,4,6-tris (monochloromethyl)- s-triazine, 2,4,6-tris (dichloromethyl) -s-triazine, 2,4,6-tris (trichloromethyl) -s-triazine, 2-methyl-4,6-bis (trichloromethyl)- s-triazine, 2-n-propyl-4,6-bis (trichloromethyl) -s-triazine, 2- (α, α, β-trichloroethyl) -4,6-bis (trichloromethyl) -s-triazine 2-phenyl-4,6-bis (trichloromethyl) -s-triazine, 2- (p-methoxyphenyl) -4,6-bis (trichloromethyl) -s-triazine, 2 (3,4-epoxyphenyl) -4,6-bis (trichloromethyl) -s-triazine, 2- (p-chlorophenyl) -4,6-bis (trichloromethyl) -s-triazine, 2- [1- (P-methoxyphenyl) -2,4-butadienyl] -4,6-bis (trichloromethyl) -s-triazine, 2-styryl-4,6-bis (trichloromethyl) -s-triazine, 2- (p -Methoxystyryl) -4,6-bis (trichloromethyl) -s-triazine, 2- (pi-propyloxystyryl) -4,6-bis (trichloromethyl) -s-triazine, 2- (p- Tolyl) -4,6-bis (trichloromethyl) -s-triazine, 2- (4-natoxynaphthyl) -4,6-bis (trichloromethyl) -s-triazine, 2-phenyl O-4,6-bis (trichloromethyl) -s-triazine, 2-benzylthio-4,6-bis (trichloromethyl) -s-triazine, 2,4,6-tris (dibromomethyl) -s-triazine, 2,4,6-tris (tribromomethyl) -s-triazine, 2-methyl-4,6-bis (tribromomethyl) -s-triazine, 2-methoxy-4,6-bis (tribromomethyl) -S-triazine, and the like.

  Examples of the carbonyl compound include benzophenone derivatives such as benzophenone, Michler ketone, 2-methylbenzophenone, 3-methylbenzophenone, 4-methylbenzophenone, 2-chlorobenzophenone, 4-bromobenzophenone, and 2-carboxybenzophenone; Dimethoxy-2-phenylacetophenone, 2,2-diethoxyacetophenone, 1-hydroxycyclohexyl phenylketone, α-hydroxy-2-methylphenylpropanone, 1-hydroxy-1-methylethyl- (p-isopropylphenyl) ketone, 1-hydroxy-1- (p-dodecylphenyl) ketone, 2-methyl- (4 ′-(methylthio) phenyl) -2-morpholino-1-propanone, 1,1,1-trichloromethyl- (p-butyl) Acetophenone derivatives such as phenyl) ketone; thioxanthone derivatives such as thioxanthone, 2-ethylthioxanthone, 2-isopropylthioxanthone, 2-chlorothioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, 2,4-diisopropylthioxanthone; and benzoic acid ester derivatives such as ethyl p-dimethylaminobenzoate and ethyl p-diethylaminobenzoate.

  As the azo compound, for example, an azo compound described in JP-A-8-108621 can be used.

  Examples of the organic peroxide compound include trimethylcyclohexanone peroxide, acetylacetone peroxide, 1,1-bis (tert-butylperoxy) -3,3,5-trimethylcyclohexane, 1,1-bis (tert-butyl). Peroxy) cyclohexane, 2,2-bis (tert-butylperoxy) butane, tert-butyl hydroperoxide, cumene hydroperoxide, diisopropylbenzene hydroperoxide, 2,5-dimethylhexane-2,5-dihydro Peroxide, 1,1,3,3-tetramethylbutyl hydroperoxide, tert-butylcumyl peroxide, dicumyl peroxide, 2,5-dimethyl-2,5-di (tert-butylperoxy) hexane, , 5-oxanoyl peroxide, succinic peroxide, benzoyl peroxide, 2,4-dichlorobenzoyl peroxide, diisopropyl peroxydicarbonate, di-2-ethylhexyl peroxydicarbonate, di-2-ethoxyethyl peroxy Dicarbonate, dimethoxyisopropyl peroxycarbonate, di (3-methyl-3-methoxybutyl) peroxydicarbonate, tert-butyl peroxyacetate, tert-butyl peroxypivalate, tert-butyl peroxyneodecanoate, tert-butyl peroxyoctanoate, tert-butyl peroxylaurate, tersyl carbonate, 3,3 ′, 4,4′-tetra- (t-butylperoxycarbonyl) benzophenone, 3,3 ′, , 4′-tetra- (t-hexylperoxycarbonyl) benzophenone, 3,3 ′, 4,4′-tetra- (p-isopropylcumylperoxycarbonyl) benzophenone, carbonyldi (t-butylperoxydihydrogen dihydrogen) Phthalate), carbonyldi (t-hexylperoxydihydrogen diphthalate), and the like.

  Examples of the metallocene compound include JP-A-59-152396, JP-A-61-151197, JP-A-63-41484, JP-A-2-249, JP-A-2-4705, Various titanocene compounds described in JP-A-5-83588, such as di-cyclopentadienyl-Ti-bis-phenyl, di-cyclopentadienyl-Ti-bis-2,6-difluorophen-1-yl Di-cyclopentadienyl-Ti-bis-2,4-di-fluorophen-1-yl, di-cyclopentadienyl-Ti-bis-2,4,6-trifluorophen-1-yl, Di-cyclopentadienyl-Ti-bis-2,3,5,6-tetrafluorophen-1-yl, di-cyclopentadienyl-Ti-bis-2,3,4,5,6-pen Fluorophen-1-yl, di-methylcyclopentadienyl-Ti-bis-2,6-difluorophen-1-yl, di-methylcyclopentadienyl-Ti-bis-2,4,6-trifluoro Phen-1-yl, di-methylcyclopentadienyl-Ti-bis-2,3,5,6-tetrafluorophen-1-yl, di-methylcyclopentadienyl-Ti-bis-2,3 Examples include 4,5,6-pentafluorophen-1-yl, iron-arene complexes described in JP-A-1-304453 and JP-A-1-152109, and the like.

  Examples of the hexaarylbiimidazole compound include Japanese Patent Publication No. 6-29285, US Pat. No. 3,479,185, US Pat. No. 4,311,783, US Pat. No. 4,622. 286, etc., specifically 2,2′-bis (o-chlorophenyl) -4,4 ′, 5,5′-tetraphenylbiimidazole, 2,2′-bis (O-bromophenyl)) 4,4 ′, 5,5′-tetraphenylbiimidazole, 2,2′-bis (o, p-dichlorophenyl) -4,4 ′, 5,5′-tetraphenylbiimidazole 2,2′-bis (o-chlorophenyl) -4,4 ′, 5,5′-tetra (m-methoxyphenyl) biidazole, 2,2′-bis (o, o′-dichlorophenyl) -4,4 ', 5, '-Tetraphenylbiimidazole, 2,2'-bis (o-nitrophenyl) -4,4', 5,5'-tetraphenylbiimidazole, 2,2'-bis (o-methylphenyl) -4, Examples include 4 ′, 5,5′-tetraphenylbiimidazole, 2,2′-bis (o-trifluorophenyl) -4,4 ′, 5,5′-tetraphenylbiimidazole, and the like.

  Examples of the organic borate compound include JP-A-62-143044, JP-A-62-1050242, JP-A-9-188865, JP-A-9-188686, and JP-A-9-188710. JP, 2000-131837, JP 2002-107916, JP 764769, and Kunz, Martin “Rad Tech '98. Proceeding April 19-22, 1998, Chicago”. Organoboron salts, organoboron sulfonium complexes or organoboron oxosulfonium complexes described in JP-A-6-157623, JP-A-6-175564, JP-A-6-175561, JP-A-6-175554 , Described in JP-A-6-175553 Organoboron iodonium complexes, organoboron phosphonium complexes described in JP-A-9-188710, JP-A-6-348011, JP-A-7-128785, JP-A-7-140589, JP-A-7-306527 And organic boron transition metal coordination complexes described in JP-A-7-292014.

  Examples of the disulfone compound include compounds described in JP-A Nos. 61-166544 and 2002-328465.

  Examples of the oxime ester compound include J.I. C. S. Perkin II (1979) 1653-1660; C. S. Perkin II (1979) pages 156-162, Journal of Photopolymer Science and Technology (1995) pages 202-232, compounds described in JP-A 2000-66385, compounds described in JP-A 2000-80068, specific examples Includes compounds represented by the following formulae.

  Examples of the onium salt compound include the compounds described above as the cationic polymerization initiator, and S.I. I. Schlesinger, Photogr. Sci. Eng. , 18, 387 (1974), T.A. S. Bal et al, Polymer, 21, 423 (1980), diazonium salt, US Pat. No. 4,069,055, ammonium salt described in JP-A-4-365049, US Pat. No. 4,069, No. 055, U.S. Pat. No. 4,069,056, phosphonium salts, European Patent No. 104,143, U.S. Pat. No. 339,049, U.S. Pat. No. 410,201 , Iodonium salts described in JP-A-2-150848 and JP-A-2-296514, European Patent 370,693, European Patent 390,214, European Patent 233,567 Specification, European Patent No. 297,443, European Patent No. 297,442, US Patent No. 4,933,377, US US Patent No. 161,811, US Pat. No. 410,201, US Pat. No. 339,049, US Pat. No. 4,760,013, US Pat. No. 4,734,444 Specification, US Pat. No. 2,833,827, German Patent 2,904,626, German Patent 3,604,580, German Patent 3,604,581 Sulfonium salts described in the specification, V. Crivello et al, Macromolecules, 10 (6), 1307 (1977), J. MoI. V. Crivello et al, J.A. Polymer Sci. , Polymer Chem. Ed. , 17, 1047 (1979), a selenonium salt described in C.I. S. Wen et al, Teh, Proc. Conf. Rad. Curing ASIA, p478 Tokyo, Oct (1988), and onium salts such as arsonium salts.

  Among these, the said oxime ester compound or a diazonium salt, an iodonium salt, and a sulfonium salt are mentioned especially from the surface of reactivity and stability. In the present invention, these onium salts also have a function as a cationic polymerization initiator, but also function as an ionic radical polymerization initiator. Using this property, it is possible to activate both cationic polymerization and radical polymerization with a single compound.

  In order to further sensitize the polymerization initiator, it is possible to add a sensitization aid. Examples of the sensitizing aid include coumarins having a substituent at the 3-position and / or 7-position, flavones, dibenzalacetones, dibenzalcyclohexanes, chalcones, xanthenes, and thioxanthenes. Porphyrins, phthalocyanines, acridines, anthracenes and the like can be used.

  0.1-10 mass% is preferable, as for content in the total solid of the said photosensitive composition of the said polymerization initiator, 1-7 mass% is more preferable, and 1.5-5 mass% is especially preferable. In this range, a recording layer having excellent sensitivity and multiplicity can be formed. When the content is less than 0.1% by mass, sufficient sensitivity may not be obtained. When the content exceeds 10% by mass, the reference light and the information light are unnecessarily absorbed. In some cases, it is not possible to obtain sufficient signal strength when reading the data.

-Polymer matrix-
The polymer matrix is not particularly limited and may be appropriately selected depending on the intended purpose. However, the polymer matrix is a three-dimensionally crosslinked polymer matrix in terms of storage stability with time and mechanical toughness of the drawn hologram image. Preferably there is. The three-dimensional cross-linking of the polymer matrix is particularly preferable from the viewpoint of temporal storage stability of a hologram image drawn that has already been formed at the time of drawing the hologram.

In order to provide a thick film holographic material and obtain a sufficiently strong reproduction light, the polymer matrix is preferably formed by in situ formation from a solvent-free photosensitive composition. In situ formation of the matrix is also called in-situ polymerization and is not formed when preparing the photosensitive composition. After preparation, an appropriate treatment such as heat treatment, light irradiation treatment, or an appropriate time passes. This means that the components contained in the photosensitive composition are formed by causing a chemical reaction.
Examples of the photosensitive composition capable of performing such in situ matrix formation include reaction of isocyanate and alcohol, reaction of isocyanate and amine, reaction of epoxy compound and mercaptan compound, reaction of epoxy compound and amine, Condensation polymerization of melamine and formaldehyde, radical polymerization of radical polymerizable monomer, cationic polymerization of cationic polymerizable monomer, anionic polymerization of anionic polymerizable monomer, addition reaction of mercaptan and unsaturated ester, silane compound and ethylenic by hydrosilylation Examples thereof include a reaction with a double bond-containing compound. From the viewpoints of productivity of the photosensitive layer, and that the polymerizable compound and the polymerization initiator necessary for drawing the hologram are not consumed in the matrix formation reaction, and shortening the time required until the reaction is completed, isocyanate and alcohol, isocyanate And in situ matrix formation by reaction of epoxy and amine, epoxy and mercaptan compounds, epoxy and amine.

  Polyurethane is formed in the reaction between isocyanate and alcohol, and polyurethane is formed in the reaction between isocyanate and amine. As a compound that can be used as an isocyanate, a bifunctional or higher functional isocyanate is necessary to form a three-dimensional crosslinked polymer matrix. Specific examples include hexamethylene diisocyanate, xylylene diisocyanate, toluene diisocyanate, diphenylmethane diisocyanate. Hexahydroxylylene diisocyanate (diisocyanate methylcyclohexane), dicyclohexylmethane diisocyanate, isophorone diisocyanate, tris (6-isocyanatohexyl) isocyanurate, 2,6-diisocyanatohexanoic acid 2-isocyanate ethyl, and these isocyanate compounds, Ethylene glycol, diethylene glycol, polyethylene glycol, propylene glycol, Propylene glycol, polypropylene glycol, 1,4-butanediol, polytetramethylene glycol, glycerin, trimethylolpropane, pentaerythritol, glycerin, trimethylolpropane, pentaerythritol modified with polyethylene glycol, polypropylene glycol modified, polytetramethylene glycol Examples include dipolymers such as modified products, and prepolymers with tri- and tetra-alcohol compounds. These may be used alone or in combination of two or more compounds. It is particularly preferable that it is a liquid at room temperature or a solid having a melting point of 100 ° C. or less from the viewpoint of ease of production, and when two or more kinds of compounds are used in combination, the mixture should be a liquid at room temperature. preferable.

  As the alcohol, a bifunctional or higher functional alcohol compound is essential for forming a three-dimensional cross-linked polymer matrix. Specific examples include ethylene glycol, diethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, and polypropylene. Glycol, 1,4-butanediol, polytetramethylene glycol, glycerin, trimethylolpropane, pentaerythritol, glycerin, trimethylolpropane, pentaerythritol modified with polyethylene glycol, polypropylene glycol modified, polytetramethylene glycol modified, etc. Various polyester polyols derived from esterification reaction with di- or tri-, tetra-alcohol compounds and dicarboxylic acids Those known Te, hexanediol, heptane diols, octanediol, decanediol, and the like terminal diols dodecanediol such straight chain alkylene. These compounds may be used alone or in combination of two or more. A liquid at normal temperature is preferable from the viewpoint of easy work.

  As the amine, it is essential for forming a three-dimensionally crosslinked polymer matrix that two or more active NH bonds are contained. For example, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, polyamine compound And various amines that are commercially available as curing agents for isocyanates.

  The reaction between the isocyanate and alcohol or the isocyanate and amine can be more effectively carried out by a curing accelerator. Specific examples of such curing accelerators include, for example, dibutyltin dilaurate, dilauratetin, triethylamine, tributylamine, diisopropylethylamine, diazabicycloundecane, tris-2,4,6- (dimethylaminomethyl) phenol. Can be mentioned.

  The aromatic epoxide is a di- or polyglycidyl ether produced by a reaction between a polyhydric phenol having at least one aromatic nucleus or an alkylene oxide adduct thereof and epichlorohydrin, such as bisphenol A or an alkylene oxide addition thereof. And di- or polyglycidyl ether of hydrogenated bisphenol A or its alkylene oxide adduct, or novolac-type epoxy resin. Here, as said alkylene oxide, ethylene oxide, a propylene oxide, etc. are mentioned, for example, Among these, ethylene oxide is especially preferable.

  As the alicyclic epoxide, cyclohexene oxide obtained by epoxidizing a compound having at least one cycloalkane ring such as cyclohexene or cyclopentene ring with an appropriate oxidizing agent such as hydrogen peroxide or peracid. Alternatively, a cyclopentene oxide-containing compound is preferable, and specific examples include the compounds shown below.

Examples of the aliphatic epoxide include aliphatic polyhydric alcohols or di- or polyglycidyl ethers of alkylene oxide adducts thereof, and typical examples thereof include diglycidyl ether of ethylene glycol, diglycidyl ether of propylene glycol, or 1 Of diglycidyl ether of alkylene glycol such as diglycidyl ether of 1,6-hexanediol, polyglycidyl ether of polyhydric alcohol such as di- or triglycidyl ether of glycerin or its alkylene oxide adduct, polyethylene glycol or its adduct of alkylene oxide Examples include diglycidyl ethers of polyalkylene glycols such as diglycidyl ether, polypropylene glycol or diglycidyl ether of alkylene oxide adducts thereof. It is. Here, examples of the alkylene oxide include ethylene oxide and propylene oxide, and among these, ethylene oxide is particularly preferable.
These may be used alone or in combination of two or more. Among these, it is preferable to have an ethylene oxide part from the point that coloring does not occur during laser irradiation.

  As said thiol group containing compound, a mercapto compound is mentioned suitably, for example. The mercapto compound is preferably bifunctional or more from the viewpoint of imparting mechanical strength to the photosensitive composition to be formed. Such a mercapto compound is not particularly limited and may be appropriately selected depending on the purpose. For example, an addition reaction between an excess of low-molecular dimercaptan and a polyepoxide compound, a reaction between polyepoxide and hydrogen sulfide, Examples thereof include polymercaptan compounds derived from an esterification reaction of propionic acid or mercaptoglycolic acid and a polyhydric alcohol. Specifically, as dimercaptan, dimercaptoethane, dimercaptobutane, dimercaptohexane, dimercaptooctane, and polyepoxide compound as bisphenol A or its hydrogenated product, glycerol, trimethylolpropane, pentaerythritol, dimercapto Pentaerythritol, phthalic acid, terephthalic acid, isophthalic acid, trimellitic acid, pyromellitic acid, or an epoxy-terminated polyethylene glycol modified product of a hydrogenated product of these aromatic polycarboxylic acids, a polypropylene glycol modified product, a polyhydric alcohol compound, OH-terminated polyethylene glycol of glycerol, trimethylolpropane, pentaerythritol, dipentaerythritol, phthalic acid, terephthalic acid, isophthalic acid, trimellitic acid, pyromellitic acid Le modified product, such as polypropylene glycol.

  Examples of the polyamine compound include compounds having a plurality of functional groups selected from primary amino groups and secondary amino groups. Examples of the polyamine compound include diaminodiphenylmethane, m-phenylenediamine, diaminodiphenylsulfone, cyclohexylamine, m-xylylenediamine, 4,4-diamino-3,3 diethyldiphenylmethane, diethylenetriamine, tetraethylenepentamine, N- Examples include aminoethylpiverazine, isophoronediamine, dicyandiamide, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, and compounds that are commercially available as alkyl branched polyamines. Moreover, the compound which modified | denatured the terminal of the said polyepoxide with the said diamine is also used suitably. Among these, it is preferable to have an ethylene oxide part from the point that coloring does not occur during laser irradiation.

  The mixing mass ratio [((1) component: (2) component)] of the epoxy compound (1) and the compound (2) is preferably 1: 0.7 to 1: 1.2, 0.8-1: 1.1 is more preferable. Within this range, a photosensitive composition excellent in mechanical properties such as bending resistance, tensile strength, yield point, dimensional stability and weather resistance of the cured product can be obtained. If the content is outside the numerical range, the mechanical properties of the cured product may be impaired.

  The content of the polymer matrix is preferably 60 to 99% by mass, more preferably 70 to 95% by mass, and still more preferably 75 to 90% by mass with respect to the total solid content of the photosensitive composition. Within this range, a photosensitive composition having excellent sensitivity, multiple characteristics, and recorded information storage stability can be obtained. When the content is less than 60% by mass, the storage stability of recorded information may be deteriorated, and when it exceeds 99% by mass, sufficient sensitivity and multiplicity may not be obtained for volume holographic applications. is there.

  The polymerization reaction that can form a polymer matrix is not particularly limited and may be appropriately selected depending on the intended purpose. For example, cationic epoxy polymerization, cationic vinyl ether polymerization, cationic alkenyl ether polymerization, cationic allene ether polymerization, cation There are ketene acetal polymerization, unsaturated ester-amine step polymerization (by Michael addition), unsaturated ester-mercaptan step polymerization (by Michael addition), vinyl-silicon hydride step polymerization (hydrosilylation).

  Said reaction is enabled or facilitated by a suitable catalyst. For example, cationic epoxy polymerization occurs rapidly at room temperature using a catalyst based on BF3, other cationic polymerization proceeds in the presence of protons, epoxy-mercaptan reaction and Michael addition are promoted by a base such as an amine, Hydrosilylation proceeds rapidly in the presence of a transition metal catalyst such as platinum, and urethane and urea formation proceeds rapidly when a tin catalyst is used. It is also possible to use a photogenerating catalyst for matrix formation if measures are taken to prevent polymerization of the photoactive monomer during photogeneration.

-Curing accelerator-
The photosensitive composition preferably further contains a curing accelerator.
Examples of the curing accelerator include tertiary alkyl amines, tertiary aromatic amines, and alicyclic tertiary amines.
Examples of the tertiary alkylamine include triethylamine, tributylamine, diisopropylethylamine, triethanolamine and the like.
Examples of the tertiary aromatic amine include tris-2,4,6- (dimethylaminomethyl) phenol and dimethylbenzylamine.
Examples of the alicyclic tertiary amine include hexamethylenetetramine, diazabicycloundecane (DBU), diazabicyclooctane (DABCO), and the like.
0.1-10 mass% is preferable, as for content in the total solid of the said photosensitive composition of the said hardening accelerator, 1-7 mass% is more preferable, and 1.5-5 mass% is still more preferable. Within this range, it is possible to obtain a photosensitive composition that is excellent in mechanical properties and can be cured rapidly.

  The photosensitive composition of the present invention is used for forming a recording layer for recording information using holography. The following optical recording medium of the present invention, the optical recording method of the present invention, the optical reproducing method of the present invention, and It is particularly preferably used in the optical recording apparatus of the present invention.

(Optical recording medium)
An optical recording medium of the present invention comprises the above-mentioned photosensitive composition of the present invention, and has a recording layer for recording information using holography, at least a first substrate, a selective reflection layer, and a recording layer And the second substrate in this order are preferable, and further include other layers as necessary.

  The optical recording medium of the present invention is not particularly limited as long as it can be recorded and reproduced using the principle of hologram, and can store 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 volume hologram to be recorded, and may be either a transmission type or a reflection type. The hologram recording method may be any, for example, an amplitude hologram, a phase hologram, a blazed hologram, a complex amplitude hologram, or the like.

  There is no restriction | limiting in particular as thickness of the said recording layer, According to the objective, it can select suitably, 100-1,000 micrometers is preferable, 150-700 micrometers is more preferable, 200-500 micrometers is still more preferable. Within this range, it is possible to perform good volume holographic optical information recording with high manufacturability. If the thickness exceeds 1,000 μm, it may be difficult in terms of cost and manufacturing method, and if it is less than 100 μm, it may not be possible to achieve both signal strength and multiplexing performance.

<Board>
The shape, structure, size and the like of the substrate are not particularly limited and can be appropriately selected according to the purpose. Examples of the shape include a disk shape, a card shape, a plate shape, and a sheet shape. The structure may be a single layer structure or a laminated structure, and the size may be appropriately selected according to the size of the optical recording medium. .

The material of the substrate is not particularly limited, and any of inorganic materials and organic materials can be preferably used. However, the mechanical strength of the optical recording medium can be ensured, and light used for recording and reproduction can be obtained. In the case of a transmissive type incident through a substrate, it is necessary to be sufficiently transparent in the wavelength region of light used.
Examples of the inorganic material include glass, quartz, silicon, and the like.
Examples of the organic material include acetate resins such as triacetyl cellulose, polyester resins, polyethersulfone resins, polysulfone resins, polycarbonate resins, polyamide resins, polyimide resins, polyolefin resins, and acrylic resins. Polynorbornene resin, cellulose resin, polyarylate resin, polystyrene resin, polyvinyl alcohol resin, polyvinyl chloride resin, polyvinylidene chloride resin, polyacrylic resin, polylactic acid resin, plastic film laminated paper And synthetic paper. These may be used individually by 1 type and may use 2 or more types together. Among these, polycarbonate resins and acrylic resins are preferable from the viewpoints of moldability, optical characteristics, and cost.

As said board | substrate, what was produced suitably may be used and a commercial item may be used.
There is no restriction | limiting in particular as thickness of the said 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 less than 0.1 mm, distortion of the shape during storage of the disc may not be suppressed. If the thickness exceeds 5 mm, the mass of the entire disc increases and is rotated by a drive motor or the like. In some cases, an excessive load may be applied.

  The substrate is provided with a plurality of address-servo areas serving as positioning areas extending linearly in the radial direction 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) (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.

-Reflective film-
The reflective film is formed on the surface of the servo pit pattern of the substrate.
As the material of the reflective film, a material having a high reflectance with respect to recording light or reference light is preferably used. When the wavelength of light to be used is 400 to 780 nm, for example, Al, Al alloy, Ag, Ag alloy, etc. are preferably used. When the wavelength of light to be used is 650 nm or more, it is preferable to use Al, Al alloy, Ag, Ag alloy, Au, Cu alloy, TiN, or the like.
As the reflective film, an optical recording medium that reflects light and can be written or erased, such as a DVD (digital video disk), is used. It is also possible to add and rewrite directory information such as information on which part has an error and how replacement processing is performed without affecting the hologram.

The formation of 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 realized.

<Selective reflection layer>
The selective reflection layer is provided on a servo pit of the substrate or on the reflection layer.
The selective reflection layer has a wavelength selective reflection function of reflecting only light of a specific wavelength from among a plurality of types of light rays. In particular, the selective reflection wavelength does not shift even when the incident angle changes, and the function of preventing irregular reflection from the reflection film of the optical recording medium by the information light and the reference light, and also preventing the occurrence of noise. By laminating the selective reflection layer on the recording medium, optical recording with high resolution and excellent diffraction efficiency can be obtained.
There is no restriction | limiting in particular as said selective reflection layer, According to the objective, it can select suitably, For example, a dichroic mirror layer, a color material containing layer, a dielectric material vapor deposition layer, a single layer or two or more cholesteric layers, and required It is formed by a laminate in which at least one of other layers appropriately selected according to the above is laminated.
The selective reflection layer may be laminated together with the direct recording layer on the substrate by coating or the like. The selective reflection layer is laminated on a substrate such as a film to produce a selective reflection layer, which is laminated on the substrate. Also good.

-Dichroic mirror layer-
The dichroic mirror layer is preferably laminated in a plurality of layers to be a wavelength selective reflection film. The number of stacked layers is preferably 1 to 50 layers, more preferably 2 to 40 layers, and particularly preferably 2 to 30 layers. When the number of stacked layers exceeds 50 layers, production efficiency decreases due to multi-layer deposition, the change in spectral transmittance characteristics decreases, and the effect of increasing the number of layers decreases.

  There is no restriction | limiting in particular as a material in the said dichroic mirror layer, Although it can select suitably according to the objective, For example, Ag, Au, Pt, Al, or these alloys etc. are mentioned.

There is no restriction | limiting in particular as a lamination | stacking method of the said dichroic mirror layer, According to the objective, it can select suitably, For example, physical vapor deposition methods (Vapor deposition methods, such as ion plating and an ion beam, sputtering) ( PVD method), chemical vapor deposition method (CVD method), and the like. Among these, vacuum deposition and sputtering are preferable, and sputtering is more preferable.
As the sputtering, a DC sputtering method having a high film formation rate is preferable. In the DC sputtering method, it is preferable to use a material having high conductivity.
In addition, as a method for forming a multilayer film by sputtering, for example, (1) a one-chamber method in which a plurality of targets are alternately or sequentially formed in one chamber, and (2) continuous film formation in a plurality of chambers. There is a multi-chamber method. Among these, the multi-chamber method is particularly preferable from the viewpoint of preventing productivity and material contamination.
The thickness of the dichroic mirror layer is preferably λ / 16 to λ, more preferably λ / 8 to 3λ / 4, and more preferably λ / 6 to 3λ / 8 in the optical wavelength order.

-Color material-containing layer-
The color material-containing layer is formed of a color material, a binder resin, a solvent, and other components as necessary.

  As the coloring material, at least one of a pigment and a dye is preferably exemplified, and among these, a red dye and a red pigment are preferable from the viewpoint of absorbing light at 532 nm and transmitting servo light at 655 nm or 780 nm, Red pigments are particularly preferred.

  There is no restriction | limiting in particular as said red dye, According to the objective, it can select suitably from well-known things, for example, C.I. I. Acid Red 1, 8, 13, 14, 18, 26, 27, 35, 37, 42, 52, 82, 87, 89, 92, 97, 106, 111, 114, 115, 134, 186, 249, 254 Acid dyes such as 289; C.I. I. Basic Red 2, 12, 13, 14, 15, 18, 22, 23, 24, 27, 29, 35, 36, 38, 39, 46, 49, 51, 52, 54, 59, 68, 69, 70, Basic dyes such as 73, 78, 82, 102, 104, 109, 112; I. And reactive dyes such as reactive red 1, 14, 17, 25, 26, 32, 37, 44, 46, 55, 60, 66, 74, 79, 96, and 97. These may be used individually by 1 type and may use 2 or more types together.

  There is no restriction | limiting in particular as said red pigment, According to the objective, it can select suitably from well-known things, for example, C.I. I. Pigment red 9, C.I. I. Pigment red 97, C.I. I. Pigment red 122, C.I. I. Pigment red 123, C.I. I. Pigment red 149, C.I. I. Pigment red 168, C.I. I. Pigment red 177, C.I. I. Pigment red 180, C.I. I. Pigment red 192, C.I. I. Pigment red 209, C.I. I. Pigment red 215, C.I. I. Pigment red 216, C.I. I. Pigment red 217, C.I. I. Pigment red 220, C.I. I. Pigment red 223, C.I. I. Pigment red 224, C.I. I. Pigment red 226, C.I. I. Pigment red 227, C.I. I. Pigment red 228, C.I. I. Pigment red 240, C.I. I. Pigment Red 48: 1, Permanent Carmine FBB (CI Pigment Red 146), Permanent Ruby FBH (CI Pigment Red 11), Fastel Pink B Splash (CI Pigment Red 81), etc. Is mentioned. These may be used individually by 1 type and may use 2 or more types together.

  Among these, a red pigment exhibiting a transmission spectrum in which the transmittance for 532 nm light is 10% or less and the transmittance for 655 nm light is 90% or more is particularly preferably used.

  As content of the said color material, 0.05-90 mass% is preferable with respect to the total solid mass of the said color material content layer, and 0.1-70 mass% is more preferable. When the content is less than 0.05% by mass, the thickness of the color material-containing layer may be required to be 500 μm or more, and when it exceeds 90% by mass, the self-supporting property of the color material-containing layer is lost. The film may collapse during the color material-containing layer manufacturing process.

-Binder resin-
There is no restriction | limiting in particular as said binder resin, According to the objective, it can select suitably according to the objective, For example, polyvinyl alcohol resin, a vinyl chloride / vinyl acetate copolymer; Vinyl chloride, vinyl acetate, and vinyl alcohol Copolymer with at least one of styrene, maleic acid and acrylic acid; vinyl chloride / vinylidene chloride copolymer; vinyl chloride / acrylonylol copolymer; ethylene / vinyl acetate copolymer; cellulose derivative such as nitrocellulose; polyacrylic resin , Polyvinyl acetal resin, polyvinyl butyral resin, epoxy resin, phenoxy resin, polyurethane resin, polycarbonate resin, and the like. These may be used individually by 1 type and may use 2 or more types together.
Further, in order to further improve dispersibility and durability, the binder resin molecules listed above include polar groups (epoxy groups, CO ₂ H, OH, NH ₂ , SO ₃ M, OSO ₃ M, PO ₃ M ₂ , OPO ₃ M ₂ (wherein M is a hydrogen atom, an alkali metal, or ammonium, and when there are a plurality of M in one group, may be different from each other) is preferable. The content of is preferably 10 ⁻⁶ to 10 ⁻⁴ equivalents per gram of the binder resin, and the binder resins listed above are preferably cured by adding known isocyanate crosslinking agents.

  As content of the said binder resin, 10-99.95 mass% is preferable with respect to the total solid mass of the said color material content layer, and 30-99.9 mass% is more preferable.

Each of the above components is dissolved or dispersed in an appropriate solvent, prepared as a coating solution, and this coating solution is applied onto a substrate described later by a desired coating method to form a color material-containing layer. it can.
The solvent is not particularly limited and may be appropriately selected from known solvents according to the purpose. Examples thereof include water, 3-methoxypropionic acid methyl ester, 3-methoxypropionic acid ethyl ester, and 3-methoxypropion. Alkoxypropionic acid esters such as acid propyl ester, 3-ethoxypropionic acid methyl ester, 3-ethoxypropionic acid ethyl ester, 3-ethoxypropionic acid propyl ester; 2-methoxypropyl acetate, 2-ethoxypropyl acetate, 3-methoxy Esters of alkoxy alcohols such as butyl acetate; Lactic acid esters such as methyl lactate and ethyl lactate; Ketones such as methyl ethyl ketone, cyclohexanone and methylcyclohexanone; γ-butyrolactone, N-methylpyrrolidone Dimethyl sulfoxide, chloroform, tetrahydrofuran, and the like. These may be used individually by 1 type and may use 2 or more types together.

  The coating method is not particularly limited and may be appropriately selected depending on the intended purpose. For example, the inkjet method, spin coating method, kneader coating method, bar coating method, blade coating method, casting method, dip method, curtain And coating method.

  The thickness of the color material-containing layer is, for example, preferably 0.5 to 200 μm, and more preferably 1.0 to 100 μm. When the thickness is less than 0.5 μm, it may not be possible to add a sufficient amount of a binder resin for wrapping the color material to form a film. When the thickness exceeds 200 μm, the thickness of the filter becomes too large. Thus, an excessively large optical system for irradiation light and servo light may be required.

-Dielectric deposition layer-
The dielectric vapor deposition layer is formed, for example, by laminating a plurality of thin dielectric layers having different refractive indexes, and in order to obtain a wavelength selective reflection film, a thin dielectric layer having a high refractive index and a dielectric layer having a low refractive index are used. It is preferable to laminate a plurality of thin body layers alternately, but it is not limited to two or more types, and may be more types.
The number of stacked layers is preferably 2 to 20 layers, more preferably 2 to 12 layers, still more preferably 4 to 10 layers, and particularly preferably 6 to 8 layers. If the number of stacked layers exceeds 20, the production efficiency may decrease due to multi-layer deposition, and the objects and effects of the present invention may not be achieved.

  The stacking order of the dielectric thin layers is not particularly limited and can be appropriately selected depending on the purpose. For example, when the refractive index of an adjacent film is high, a film having a lower refractive index is first selected. Laminate. Conversely, when the refractive index of the adjacent layer is low, a film having a higher refractive index is first laminated. The threshold value for determining whether the refractive index is high or low is preferably 1.8. Note that whether the refractive index is high or low is not absolute. Among high-refractive-index materials, there may be a material with a relatively high refractive index and a material with a relatively low refractive index, which are used alternately. May be.

The material for the high refractive index dielectric thin layer is not particularly limited and may be appropriately selected depending on the intended purpose. For example, Sb ₂ O ₃ , Sb ₂ S ₃ , Bi ₂ O ₃ , CeO ₂ , CeF ₃ , HfO ₂ , La ₂ O ₃ , Nd ₂ O ₃ , Pr ₆ O ₁₁ , Sc ₂ O ₃ , SiO, Ta ₂ O ₅ , TiO ₂ , TlCl, Y ₂ O ₃ , ZnSe, ZnS, ZrO ₂ , Etc. Among these, Bi ₂ O ₃ , CeO ₂ , CeF ₃ , HfO ₂ , SiO, Ta ₂ O ₅ , TiO ₂ , Y ₂ O ₃ , ZnSe, ZnS, ZrO ₂ are preferable, and among these, SiO, Ta ₂ O ₅ , TiO ₂ , Y ₂ O ₃ , ZnSe, ZnS, and ZrO ₂ are more preferable.

The material for the low refractive index dielectric thin layer is not particularly limited and may be appropriately selected depending on the intended purpose. For example, Al ₂ O ₃ , BiF ₃ , CaF ₂ , LaF ₃ , PbCl ₂ , PbF ₂ , LiF, MgF ₂ , MgO, NdF ₃ , SiO ₂ , Si ₂ O ₃ , NaF, ThO ₂ , ThF ₄ , and the like. Among these, Al ₂ O ₃ , BiF ₃ , CaF ₂ , MgF ₂ , MgO, SiO ₂ , Si ₂ O ₃ are preferable, and among these, Al ₂ O ₃ , CaF ₂ , MgF ₂ , MgO, SiO ₂ , Si ₂ O ₃ is more preferable.
The material of the dielectric thin layer is not particularly limited as to the atomic ratio, and can be appropriately selected according to the purpose. The atomic ratio can be adjusted by changing the atmospheric gas concentration during film formation. it can.

The method for laminating the dielectric thin layer is not particularly limited and may be appropriately selected depending on the purpose. For example, a physical vapor deposition method such as ion plating, vacuum deposition such as ion beam, sputtering, or the like. (PVD method), chemical vapor deposition method (CVD method), and the like. Among these, vacuum deposition and sputtering are preferable, and sputtering is more preferable.
As the sputtering, a DC sputtering method having a high film formation rate is preferable. In the DC sputtering method, it is preferable to use a material having high conductivity.
In addition, as a method for forming a multilayer film by sputtering, for example, (1) a one-chamber method in which a plurality of targets are alternately or sequentially formed in one chamber, and (2) continuous film formation in a plurality of chambers. There is a multi-chamber method. Among these, the multi-chamber method is particularly preferable from the viewpoint of preventing productivity and material contamination.
The thickness of the dielectric thin layer is preferably λ / 16 to λ, more preferably λ / 8 to 3λ / 4, and more preferably λ / 6 to 3λ / 8 in the optical wavelength order.

  In the dielectric deposition layer, a part of the light propagating in the dielectric deposition layer is multiple-reflected for each dielectric thin layer, and the reflected light interferes with each other. Only light having a wavelength determined by the product of the refractive index of the film with respect to the light is selectively transmitted. Further, the central transmission wavelength of the dielectric vapor deposition layer has an angle dependency with respect to the incident light, and the transmission wavelength can be changed by changing the incident light.

-Cholesteric liquid crystal layer-
The cholesteric liquid crystal layer contains at least a nematic liquid crystal compound and a chiral compound, and contains a polymerizable compound and, if necessary, other components.

  The cholesteric liquid crystal layer may be a single layer, or two or more layers may be laminated. There is no restriction | limiting in particular as the number of lamination | stacking of this 2 or more layers, According to the objective, it can select suitably, For example, 2-10 layers are preferable. On the other hand, when the number of laminated layers exceeds 10, the production efficiency by coating may decrease, and the object and effect of the present invention may not be achieved.

  The cholesteric liquid crystal layer preferably has a circularly polarized light separation function. The cholesteric liquid crystal layer having the function of separating circularly polarized light has only a circularly polarized light component in which the rotation direction (clockwise or counterclockwise) of the liquid crystal is coincident with the circular polarization direction and the wavelength is the helical pitch of the liquid crystal. Has a selective reflection characteristic of reflecting the light. Using the selective reflection characteristics of the cholesteric liquid crystal layer, only circularly polarized light having a specific wavelength is transmitted and separated from natural light in a certain wavelength band, and the rest is reflected. Therefore, each of the cholesteric liquid crystal layers preferably transmits the first light and reflects the circularly polarized light of the second light different from the first light, and the wavelength of the first light is 350 to 600 nm. And the wavelength of the second light is preferably 600 to 900 nm.

The selective reflection characteristic of the cholesteric liquid crystal layer is limited to a specific wavelength band, and it is difficult to cover the visible light range. That is, the selective reflection wavelength region width Δλ of the cholesteric liquid crystal layer is expressed by the following formula 1.
<Formula 1>
Δλ = 2λ (ne−no) / (ne + no)
In Equation 1, no represents the refractive index of nematic liquid crystal molecules contained in the cholesteric liquid crystal layer with respect to normal light. ne represents the refractive index of the nematic liquid crystal molecules with respect to extraordinary light. λ represents the center wavelength of selective reflection.

  As shown in Equation 1, the selective reflection wavelength bandwidth Δλ depends on the molecular structure of the nematic liquid crystal itself. From Equation 1, if (ne−no) is increased, the selective reflection wavelength bandwidth Δλ can be expanded. However, (ne−no) is usually 0.3 or less, and when it is greater than 0.3, the liquid crystal Other functions such as alignment characteristics, liquid crystal temperature, etc. are insufficient, making it difficult to put into practical use. Therefore, in reality, the selective reflection wavelength bandwidth Δλ of the cholesteric liquid crystal layer is about 150 nm at the maximum, and usually about 30 to 100 nm is preferable.

The selective reflection center wavelength λ of the cholesteric liquid crystal layer is expressed by the following formula 2.
<Formula 2>
λ = (ne + no) P / 2
However, in the said Numerical formula 2, ne and no represent the same meaning as the said Numerical formula 1. P represents the helical pitch length required for one rotation twist of the cholesteric liquid crystal layer.

As shown in Equation 2, the selective reflection center wavelength λ depends on the average refractive index and the helical pitch length P of the cholesteric liquid crystal layer if the helical pitch of the cholesteric liquid crystal layer is constant. Therefore, in order to expand the selective reflection characteristics of the cholesteric liquid crystal layer, the selective reflection center wavelengths of the cholesteric liquid crystal layers are different from each other, and the rotational directions (clockwise or counterclockwise) of the spirals of the cholesteric liquid crystal layers are the same. Preferably there is. The selective reflection wavelength band of each cholesteric liquid crystal layer is preferably continuous. Here, the “continuous” means that there is no gap between the two selective reflection wavelength bands, and the reflectance in this range is substantially 40% or more.
Therefore, the distance between the selective reflection center wavelengths λ of each cholesteric liquid crystal layer is preferably within a range in which each selective reflection wavelength band is continuous with at least one other selective reflection wavelength band.

The filter layer is a normal incidence 0 ° and to be in the range of _{± 20 ° λ 0 ~λ 0 /} cos20 ° ( However, lambda ₀ represents a wavelength of the irradiated light) that light reflectance at not less than 40% preferably, lambda ₀ to [lambda] a perpendicular incidence in the range of ± 40 ° and ₀ ° 0 _/ cos40 ° (However, lambda ₀ represents a wavelength of the irradiated light) is particularly preferred light reflectance at not less than 40%.
Wherein λ ₀ ~λ ₀ / cos20 °, especially λ ₀ ~λ ₀ / cos40 ° (However, lambda ₀ represents a wavelength of the irradiated light) as long as the light reflectance of 40% or more in the range of the angle of the irradiation light reflected The dependency can be eliminated, and a lens optical system used in a normal optical recording medium can be employed.

Specifically, when three cholesteric liquid crystal layers having different selective reflection center wavelengths and the same spiral rotation directions of the cholesteric liquid crystal layers are stacked, a filter layer having reflection characteristics as shown in FIG. can get. FIG. 4 shows that the reflection characteristic for vertically incident light from the front (0 °) is 40% or more. On the other hand, when it becomes the incident light from the oblique direction, it gradually shifts to the short wavelength side, and when tilted by 40 ° within the liquid crystal layer, the reflection characteristic as shown in FIG. 5 is shown.
Similarly, when two cholesteric liquid crystal layers having different selective reflection center wavelengths and the same spiral rotation directions of the cholesteric liquid crystal layers are stacked, a filter layer having reflection characteristics as shown in FIG. 6 is obtained. . FIG. 6 shows that the reflection characteristic for vertically incident light from the front (0 °) is 40% or more. On the other hand, when it becomes the incident light from the oblique direction, it gradually shifts to the short wavelength side, and when tilted by 20 ° in the liquid crystal layer, it shows a reflection characteristic as shown in FIG.

Note that the reflection range of λ _{0 to} 1.3λ ₀ shown in FIG. 4 is 1.3λ ₀ = 692 nm when λ ₀ = 532 nm, and the servo light is reflected when the servo light is 655 nm. The range of λ _{0 to} 1.3λ ₀ shown here is suitability for ± 40 ° incident light in the optical recording medium filter (selective reflection layer). If servo light within ± 20 ° is masked and used, servo control can be performed without any problem. If the average refractive index of each cholesteric liquid crystal layer in the filter used is sufficiently large, it is easy to design all the incident angles within ± 20 ° in the optical recording medium filter, in which case FIG. It is sufficient to stack two cholesteric liquid crystal layers of λ _{0 to} 1.1λ ₀ shown in FIG.
Therefore, from the results shown in FIGS. 4 to 7, in the optical recording medium filter, a reflectance of 40% or more can be secured even when the incident wavelength is inclined by 0 ° to 20 ° (preferably 0 ° to 40 °). Therefore, a filter layer that does not interfere with signal reading can be obtained.

  Each cholesteric liquid crystal layer is not particularly limited as long as it satisfies the above characteristics, and can be appropriately selected according to the purpose. As described above, the cholesteric liquid crystal layer contains a nematic liquid crystal compound and a chiral compound. Further, it contains other components as required.

-Nematic liquid crystal compounds-
The nematic liquid crystal compound is characterized in that the liquid crystal phase is fixed below the liquid crystal transition temperature, the liquid crystal compound having a refractive index anisotropy Δn of 0.10 to 0.40, a polymer liquid crystal compound, and polymerization The liquid crystal compound can be appropriately selected according to the purpose. While it is in a liquid crystal state at the time of melting, it can be used as a solid phase by, for example, aligning by using an alignment substrate subjected to alignment treatment such as rubbing treatment, and cooling and fixing as it is.

  There is no restriction | limiting in particular as said nematic liquid crystal compound, According to the objective, it can select suitably, For example, the following compound etc. can be mentioned.

  In the above formula, n represents an integer of 1 to 1,000. In addition, in each of the exemplified compounds, those in which the side chain linking group is changed to the following structure can also be cited as suitable.

  Among the above exemplified compounds, as the nematic liquid crystal compound, a nematic liquid crystal compound having a polymerizable group in the molecule is preferable from the viewpoint of ensuring sufficient curability, and among these, an ultraviolet (UV) polymerizable liquid crystal is preferable. Is preferred. Commercially available products can be used as the UV polymerizable liquid crystal, for example, trade name PALIOCOLOR LC242 manufactured by BASF; trade name E7 manufactured by Merck; trade name LC-Slicon-CC3767 manufactured by Wacker-Chem; Takasago Examples include trade names L35, L42, L55, L59, L63, L79, and L83 manufactured by Perfume Co., Ltd.

  As content of the said nematic liquid crystal compound, 30-99 mass% is preferable with respect to the total solid content mass of each said cholesteric liquid crystal layer, and 50-99 mass% is more preferable. When the content is less than 30% by mass, the alignment of the nematic liquid crystal compound may be insufficient.

-Chiral compounds-
The chiral compound is not particularly limited and can be appropriately selected from known compounds according to the purpose. From the viewpoint of improving the hue and color purity of the liquid crystal compound, for example, an isomalide compound, a catechin compound, an isosorbide compound, In addition to the Fencon compound, the carboxylic compound, etc., the following compounds can be exemplified. These may be used individually by 1 type and may use 2 or more types together.

  Moreover, a commercial item can be used as said chiral compound, As this commercial item, the brand name S101, R811, CB15 by Merck, and the brand name PALIOCOLOR LC756 by BASF, etc. are mentioned, for example.

  As content of the said chiral compound, 0-30 mass% is preferable with respect to the total solid content mass of each said cholesteric liquid crystal layer, and 0-20 mass% is more preferable. When the content exceeds 30% by mass, the orientation of the cholesteric liquid crystal layer may be insufficient.

-Polymerizable compound-
In the cholesteric liquid crystal layer, for example, a polymerizable compound can be used in combination for the purpose of improving the degree of curing such as film strength. When the polymerizable compound is used in combination, after changing (twisting) the twisting force of the liquid crystal by light irradiation (for example, after forming a selective reflection wavelength distribution), the helical structure (selective reflectivity) is fixed, The strength of the cholesteric liquid crystal layer after fixing can be further improved. However, when the liquid crystal compound has a polymerizable group in the same molecule, it is not necessarily added.
The polymerizable compound is not particularly limited and may be appropriately selected from known compounds according to the purpose. Examples thereof include monomers having an ethylenically unsaturated bond, and specifically, pentaerythritol. Examples thereof include polyfunctional monomers such as tetraacrylate and dipentaerythritol hexaacrylate.
Specific examples of the monomer having an ethylenically unsaturated bond include the following compounds. These may be used individually by 1 type and may use 2 or more types together.

  As addition amount of the said polymeric compound, 0-50 mass% is preferable with respect to the total solid content mass of each said cholesteric liquid crystal layer, and 1-20 mass% is more preferable. When the addition amount exceeds 50% by mass, the orientation of the cholesteric liquid crystal layer may be inhibited.

-Other ingredients-
The other components are not particularly limited and may be appropriately selected depending on the purpose. For example, photopolymerization initiator, sensitizer, binder resin, polymerization inhibitor, solvent, surfactant, thickener , Dyes, pigments, ultraviolet absorbers, gelling agents, and the like.

There is no restriction | limiting in particular as said photoinitiator, According to the objective, it can select suitably according to the objective, For example, p-methoxyphenyl-2,4-bis (trichloromethyl) -s-triazine, 2- (p-butoxystyryl) -5-trichloromethyl 1,3,4-oxadiazole, 9-phenylacridine, 9,10-dimethylbenzphenazine, benzophenone / Michler's ketone, hexaarylbiimidazole / mercaptobenzimidazole, benzyl Examples thereof include dimethyl ketal and thioxanthone / amine. These may be used individually by 1 type and may use 2 or more types together.
As the photopolymerization initiator, commercially available products can be used. Examples of the commercially available products include trade names of Irgacure 907, Irgacure 369, Irgacure 784, and Irgacure 814 manufactured by Ciba Specialty Chemicals; And Lucylin TPO.

  As addition amount of the said photoinitiator, 0.1-20 mass% is preferable with respect to the total solid content mass of each said cholesteric liquid crystal layer, and 0.5-5 mass% is more preferable. When the addition amount is less than 0.1% by mass, it may take a long time because the curing efficiency at the time of light irradiation is low, and when it exceeds 20% by mass, the light transmittance from the ultraviolet region to the visible light region is increased. May be inferior.

The sensitizer is added as necessary to increase the degree of cure of the cholesteric liquid crystal layer. There is no restriction | limiting in particular as said sensitizer, According to the objective, it can select suitably according to the objective, For example, diethyl thioxanthone, isopropyl thioxanthone, etc. are mentioned.
The addition amount of the sensitizer is preferably 0.001 to 1.0% by mass with respect to the total solid mass of each cholesteric liquid crystal layer.

There is no restriction | limiting in particular as said binder resin, According to the objective, it can select suitably according to the objective, For example, Polyvinyl alcohol; Polystyrene compounds, such as a polystyrene and poly-alpha-methylstyrene; Methylcellulose, ethylcellulose, acetyl Cellulose resins such as cellulose; acidic cellulose derivatives having a carboxyl group in the side chain; acetal resins such as polyvinyl formal and polyvinyl butyral; methacrylic acid copolymer, acrylic acid copolymer, itaconic acid copolymer, crotonic acid copolymer Examples thereof include a polymer, a maleic acid copolymer, a partially esterified maleic acid copolymer; a homopolymer of acrylic acid alkyl ester or a homopolymer of alkyl methacrylate, and other polymers having a hydroxyl group. These may be used individually by 1 type and may use 2 or more types together.
Examples of the alkyl group in the homopolymer of acrylic acid alkyl ester or homopolymer of methacrylic acid alkyl ester include, for example, methyl group, ethyl group, n-propyl group, n-butyl group, iso-butyl group, and n-hexyl group. Cyclohexyl group, 2-ethylhexyl group, and the like.
Examples of the other polymer having a hydroxyl group include benzyl (meth) acrylate / (homopolymer of methacrylic acid) acrylic acid copolymer, benzyl (meth) acrylate / (meth) acrylic acid / multiple monomers of other monomers. Polymer, and the like.

  As addition amount of the said binder resin, 0-80 mass% is preferable with respect to the total solid mass of each said cholesteric liquid crystal layer, and 0-50 mass% is more preferable. When the addition amount exceeds 80% by mass, the orientation of the cholesteric liquid crystal layer may be insufficient.

There is no restriction | limiting in particular as said polymerization inhibitor, According to the objective, it can select suitably, For example, hydroquinone, hydroquinone monomethyl ether, phenothiazine, benzoquinone, or these derivatives etc. are mentioned.
As addition amount of the said polymerization inhibitor, 0-10 mass% is preferable with respect to solid content of the said polymeric compound, and 100 ppm-1 mass% is more preferable.

  The solvent is not particularly limited and may be appropriately selected from known solvents according to the purpose. For example, 3-methoxypropionic acid methyl ester, 3-methoxypropionic acid ethyl ester, 3-methoxypropionic acid propyl Esters, alkoxypropionic acid esters such as 3-ethoxypropionic acid methyl ester, 3-ethoxypropionic acid ethyl ester, 3-ethoxypropionic acid propyl ester; 2-methoxypropyl acetate, 2-ethoxypropyl acetate, 3-methoxybutyl acetate Esters of alkoxy alcohols such as: Lactic acid esters such as methyl lactate and ethyl lactate; Ketones such as methyl ethyl ketone, cyclohexanone and methylcyclohexanone; γ-butyrolactone, N-methylpyrrolidone, di Sulfoxide, chloroform, tetrahydrofuran, and the like. These may be used individually by 1 type and may use 2 or more types together.

<Other layers>
There is no restriction | limiting in particular as said other layer, According to the objective, it can select suitably, For example, a 1st gap layer, a 2nd gap layer, etc. are mentioned.

-First gap layer-
The first gap layer is provided between the selective reflection layer and the reflection film as necessary, and is formed for the purpose of smoothing the second substrate surface. It is also effective for adjusting the size of the hologram generated in the recording layer. That is, since the recording layer needs to form an interference region of the reference light and the information light to a certain size, 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 said 1st gap layer, According to the objective, it can select suitably, 1-100 micrometers is preferable.

-Second gap layer-
The second gap layer is provided between the recording layer and the selective reflection layer as necessary. In the second gap layer, if the portion of the point where the information light and the reference light are focused is filled with a photopolymer, excessive exposure of the monomer occurs when the overexposure is performed, and the multiple recording capability may be reduced. There is a function to prevent this harmful effect.
There is no restriction | limiting in particular as a material of said 2nd gap layer, According to the objective, it can select suitably, For example, a triacetyl cellulose (TAC), a polycarbonate (PC), a polyethylene terephthalate (PET), 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 And norbornene-based 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 said 2nd gap layer, According to the objective, it can select suitably, 1-200 micrometers is preferable.

Here, the optical recording medium of the present invention will be described in more detail with reference to the drawings.
FIG. 3 is a schematic cross-sectional view showing the configuration of the optical recording medium in the embodiment of the present invention. In the optical recording medium 21 according to this embodiment, the servo pit pattern 3 is formed on the first substrate 1 made of polycarbonate resin, and the reflective film 2 is coated on the servo pit pattern 3 with aluminum, gold, platinum or the like. Is provided. In FIG. 3, the servo pit pattern 3 is formed on the entire surface of the first substrate 1, but may be formed periodically. The maximum height of the servo pit is 1750 mm (175 nm), which is sufficiently smaller than the thickness of the first substrate and other layers.
On the side where the servo pits are not provided on the first substrate, a dichroic mirror layer in which Ag is selectively deposited as the selective reflection layer 6 is provided.
A recording layer 4 is provided on the reflective film 2. An optical recording medium 21 is configured by sandwiching the selective reflection film 6 and the recording layer 4 between the first substrate 1 and the second substrate 5 (a polycarbonate resin substrate).

  The optical recording medium 21 in the present embodiment may be disk-shaped or card-shaped. In this optical recording medium 21, the first substrate 1 has a thickness of 0.6 mm, the selective reflection layer 6 has a thickness of 2 to 3 μm, the recording layer 4 has a thickness of 0.6 μm, and the second substrate 5 has a thickness of 0.6 mm. The total thickness is about 1.3 mm.

  Next, the optical operation around the optical 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. Servo light is irradiated onto the optical recording medium 21 by the objective lens 12 so as to be focused 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 / exiting surface A of the optical recording medium 21 passes through the second substrate 5, the recording layer 4, and the selective reflection layer 6, is reflected by the reflective film 2, and again is the selective reflection layer. 6, passes through the recording layer 4 and the second substrate 5 and exits from 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. Since 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, the recording layer 4 is not affected. In addition, since the return light of the servo light reflected by the reflective 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-wave plate 15 at a time. Become polarized. The optical recording medium 21 is irradiated with information light and recording reference light through the dichroic mirror 13 so as to generate an interference pattern in the recording layer 4 by the objective lens 11. The information light and the recording reference light are incident 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 enter the recording layer 4 and the selective reflection layer 6, but are reflected between the bottom surface of the selective reflection layer 6 and become return light. That is, the information light and the recording reference light do not reach the reflective film 2. This is because the selective reflection layer 6 has a property of transmitting only red light.

(Optical recording method and optical reproduction method)
The optical recording method of the present invention irradiates the optical recording medium of the present invention with information light and reference light so that the optical axis of the information light and the optical axis of the reference light are coaxial, Information is recorded on the recording layer by an interference pattern generated by interference between the information light and the reference light.
The optical reproduction method of the present invention reproduces information by irradiating the interference pattern recorded on the recording layer by the reference light with the optical recording method of the present invention.
in this case. It is preferable to reproduce the recorded information by irradiating the interference pattern with the reference light at the same angle as the reference light used for recording on the optical recording medium.

In the optical recording method and the optical reproduction method of the present invention, as described above, the information light provided with a two-dimensional intensity distribution and the information light and the reference light having a substantially constant intensity are transferred into the photosensitive recording layer. Information is recorded by generating an optical characteristic distribution inside the recording layer by using the interference pattern formed by the above. On the other hand, when reading (reproducing) written information, the recording layer is irradiated with only the reference light in the same arrangement as during recording, and the reproduction has an intensity distribution corresponding to the optical characteristic distribution formed inside the recording layer. Light is emitted from the recording layer as light.
Here, the optical recording method and the optical reproduction method of the present invention are performed using the optical recording apparatus of the present invention described below.

(Optical recording device)
An optical recording apparatus (optical recording / reproducing apparatus) used in the optical recording method and optical reproducing method of the present invention will be described with reference to FIG.
FIG. 9 is an overall configuration diagram of an optical recording apparatus according to an embodiment of the present invention. The optical recording apparatus includes an optical recording apparatus and an optical reproducing apparatus.
The optical recording apparatus 100 controls a spindle 81 to which the optical recording medium 20 is attached, a spindle motor 82 that rotates the spindle 81, and the spindle motor 82 so as to keep the rotational speed of the optical recording medium 20 at a predetermined value. And a spindle servo circuit 83. The optical recording / reproducing apparatus 100 records information by irradiating the optical recording medium 20 with information light and reference light, and irradiates the optical recording medium 20 with reproduction reference light, A pickup 31 for detecting and reproducing the information recorded on the optical recording medium 20 and a drive device 84 that can move the pickup 31 in the radial direction of the optical recording medium 20 are provided.

  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 optical recording medium 20 to perform focus servo, and the tracking error signal detected by the detection circuit 85. Based on TE, a tracking servo circuit 87 that drives an actuator in the pickup 31 to move the objective lens in the radial direction of the optical recording medium 20 to perform tracking servo, a tracking error signal TE, and a command from a controller to be described later. Drive 84 controlled by a and a slide servo circuit 88 for performing a slide servo for moving the pickup 31 in the radial direction of the optical recording medium 20.

  The optical recording / reproducing apparatus 100 further decodes output data of a later-described CMOS or CCD array in the pickup 31 to reproduce data recorded in the data area of the optical recording medium 20 or reproduce from the detection circuit 85. A signal processing circuit 89 that reproduces a basic clock and discriminates an address from the signal RF, 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; It has. 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 is realized.

  Since the optical recording apparatus used in the optical recording method and the optical reproducing method of the present invention uses the optical recording medium of the present invention, both signal intensity and multiplexing performance can be achieved, and high sensitivity and high multiplexing recording can be achieved. Is possible.

  Examples of the present invention will be described below, but the present invention is not limited to these examples.

Example 1
-Production of optical recording media-
As the optical recording medium, an optical recording medium was prepared in which a second substrate, a reflective layer, an adhesive layer, a selective reflective layer, a protective layer (second gap layer), and a first substrate were laminated in this order.

--- Production of second substrate--
A second substrate made of polycarbonate resin having a diameter of 120 mm, an inner diameter of 15 mm, and a thickness of 0.6 mm was produced.

--- Production of first substrate--
As the first substrate, a general polycarbonate resin substrate used for DVD + RW having a diameter of 120 mm, an inner diameter of 15 mm, and a thickness of 0.6 mm was used. A servo pit pattern is formed on the surface of the substrate, the track pitch is 0.74 μm, the groove depth is 140 nm, and the groove width is 300 nm.
First, a reflective layer was formed on the servo pit pattern surface of the first substrate. Silver (Ag) was used as the material of the reflective layer. A 150 nm thick Ag reflective layer was formed by DC magnetron sputtering. Next, on the reflective layer, an adhesive (SD640, manufactured by Dainippon Ink & Chemicals, Inc.) is applied by spin coating to a thickness of 20 μm, and a selective reflective layer having the following composition is formed as an adhesive layer (first gap layer). Formed on top.

--Preparation of selective reflection layer--
A dichroic mirror layer composed of an Ag film having a layer number of 30 and a thickness of 3 μm is formed by vapor deposition on a polycarbonate film (manufactured by Mitsubishi Gas Chemical Co., Ltd., trade name Iupilon) with a thickness of 100 μm by a DC magnetron sputtering method. In order to laminate on the substrate, the disc was punched into the same shape as the first substrate.

<Preparation of recording layer coating solution>
A holographic recording layer coating solution having the following composition was prepared in the following tank A and tank B under a dry nitrogen atmosphere. The prepared tank was filled with dry nitrogen.
<Tank A>
-Biuret trimer of hexamethylene diisocyanate ... 292.0g
・ Hexamethylene diisocyanate: 97.4g
・ Tribromophenyl acrylate ... 42.81g
・ Tetrafunctional acrylate (pentaerythritol tetraacrylate) ... 21.41 g
・ Irgacure 784 (Ciba Specialty Chemicals Co., Ltd.) ... 14g
・ 3,5 ditertiary butyl-4-hydroxytoluene ... 210mg
<Tank B>
· Poly ^{Fox TM} T (manufactured by Omnova Solutions) ··· 817.9g
-Polypropylene oxide triol (average molecular weight 1,000) ... 517.9 g
・ Tertiary butyl peroxide ・ ・ ・ 580μl
・ Dibutyl laurate tin ... 10.2g

--Lamination of optical recording media--
First, the obtained selective reflection layer was attached to the first substrate on which the reflection layer and the adhesive layer (first gap layer) were formed, with the base film surface of the selective reflection layer facing the servo pit pattern. . The bonding was performed such that no air bubbles entered the gap. Thus, the selective reflection layer was formed on the first substrate.
Next, as a protective layer (second gap layer), an adhesive (SD640, manufactured by Dainippon Ink & Chemicals, Inc.) was applied onto the filter layer by spin coating so as to have a thickness of 20 μm. Next, the composition of the tank A and the composition of the tank B prepared above are 10 parts by mass of the tank A composition and the composition of the tank B using Posilatio (liquid mixing and injection device available from Liquid Control). Was injected into the gap between the second substrate maintained at 500 μm while mixing at a ratio of 18 parts by mass and the first substrate provided with each layer, and the composition quickly and spontaneously cured. . Thus, an optical recording medium was produced.

(Example 2)
An optical recording medium was produced in the same manner as in Example 1 except that the recording layer coating solution in Example 1 was changed to a recording layer coating solution having the following composition.
<Preparation of recording layer coating solution>
A holographic recording layer coating solution having the following composition was prepared in the following tank A and tank B under a dry nitrogen atmosphere. The prepared tank was filled with dry nitrogen.
<Tank A>
-Biuret trimer of hexamethylene diisocyanate ... 292.0g
・ Hexamethylene diisocyanate: 97.4g
・ Tribromophenyl acrylate ... 42.81g
6-functional acrylate (Kyoeisha Chemical Co., Ltd., UA-306H) ... 21.41 g
・ Irgacure 784 (Ciba Specialty Chemicals Co., Ltd.) ... 14g
・ 3,5 ditertiary butyl-4-hydroxytoluene ... 210mg
<Tank B>
· Poly ^{Fox TM} T (manufactured by Omnova Solutions) ··· 817.9g
-Polypropylene oxide triol (average molecular weight 1,000) ... 517.9 g
・ Tertiary butyl peroxide ・ ・ ・ 580μl
・ Dibutyl laurate tin ... 10.2g

(Example 3)
An optical recording medium was produced in the same manner as in Example 1 except that the recording layer coating solution in Example 1 was changed to a recording layer coating solution having the following composition.
<Preparation of recording layer coating solution>
A holographic recording layer coating solution having the following composition was prepared in the following tank A and tank B under a dry nitrogen atmosphere. The prepared tank was filled with dry nitrogen.
<Tank A>
-Biuret trimer of hexamethylene diisocyanate ... 292.0g
・ Hexamethylene diisocyanate: 97.4g
・ Tribromophenyl acrylate ... 42.81g
-5-functional acrylate (Made by Toagosei Co., Ltd., M-400) ... 21.41 g
・ Irgacure 784 (Ciba Specialty Chemicals Co., Ltd.) ... 14g
・ 3,5 ditertiary butyl-4-hydroxytoluene ... 210mg
<Tank B>
· Poly ^{Fox TM} T (manufactured by Omnova Solutions) ··· 817.9g
-Polypropylene oxide triol (average molecular weight 1,000) ... 517.9 g
・ Tertiary butyl peroxide ・ ・ ・ 580μl
・ Dibutyl laurate tin ... 10.2g

Example 4
An optical recording medium was produced in the same manner as in Example 1 except that the recording layer coating solution in Example 1 was changed to a recording layer coating solution having the following composition.
<Preparation of recording layer coating solution>
A holographic recording layer coating solution having the following composition was prepared in the following tank A and tank B under a dry nitrogen atmosphere. The prepared tank was filled with dry nitrogen.
<Tank A>
-Biuret trimer of hexamethylene diisocyanate ... 292.0g
・ Hexamethylene diisocyanate: 97.4g
・ Tribromophenyl acrylate ... 49.40g
6-functional acrylate (manufactured by Kyoeisha Chemical Co., UA-306H) ... 14.82 g
・ Irgacure 784 (Ciba Specialty Chemicals Co., Ltd.) ... 14g
・ 3,5 ditertiary butyl-4-hydroxytoluene ... 210mg
<Tank B>
· Poly ^{Fox TM} T (manufactured by Omnova Solutions) ··· 817.9g
-Polypropylene oxide triol (average molecular weight 1,000) ... 517.9 g
・ Tertiary butyl peroxide ・ ・ ・ 580μl
・ Dibutyl laurate tin ... 10.2g

(Example 5)
An optical recording medium was produced in the same manner as in Example 1 except that the recording layer coating solution in Example 1 was changed to a recording layer coating solution having the following composition.
<Preparation of recording layer coating solution>
A holographic recording layer coating solution having the following composition was prepared in the following tank A and tank B under a dry nitrogen atmosphere. The prepared tank was filled with dry nitrogen.
<Tank A>
-Biuret trimer of hexamethylene diisocyanate ... 292.0g
・ Hexamethylene diisocyanate: 97.4g
・ Tribromophenyl acrylate ・ ・ ・ 54.59g
6-functional acrylate (manufactured by Kyoeisha Chemical Co., UA-306H) ... 9.63 g
・ Irgacure 784 (Ciba Specialty Chemicals Co., Ltd.) ... 14g
・ 3,5 ditertiary butyl-4-hydroxytoluene ... 210mg
<Tank B>
· Poly ^{Fox TM} T (manufactured by Omnova Solutions) ··· 817.9g
-Polypropylene oxide triol (average molecular weight 1,000) ... 517.9 g
・ Tertiary butyl peroxide ・ ・ ・ 580μl
・ Dibutyl laurate tin ... 10.2g

(Example 6)
An optical recording medium was produced in the same manner as in Example 1 except that the recording layer coating solution in Example 1 was changed to a recording layer coating solution having the following composition.
<Preparation of recording layer coating solution>
A holographic recording layer coating solution having the following composition was prepared in the following tank A and tank B under a dry nitrogen atmosphere. The prepared tank was filled with dry nitrogen.
<Tank A>
-Biuret trimer of hexamethylene diisocyanate ... 292.0g
・ Hexamethylene diisocyanate: 97.4g
・ Tribromophenyl acrylate 61.16g
-6-functional acrylate (Kyoeisha Chemical Co., UA-306H) ... 3.06g
・ Irgacure 784 (Ciba Specialty Chemicals Co., Ltd.) ... 14g
・ 3,5 ditertiary butyl-4-hydroxytoluene ... 210mg
<Tank B>
· Poly ^{Fox TM} T (manufactured by Omnova Solutions) ··· 817.9g
-Polypropylene oxide triol (average molecular weight 1,000) ... 517.9 g
・ Tertiary butyl peroxide ・ ・ ・ 580μl
・ Dibutyl laurate tin ... 10.2g

(Example 7)
An optical recording medium was produced in the same manner as in Example 1 except that the recording layer coating solution in Example 1 was changed to a recording layer coating solution having the following composition.
<Preparation of recording layer coating solution>
A holographic recording layer coating solution having the following composition was prepared in the following tank A and tank B under a dry nitrogen atmosphere. The prepared tank was filled with dry nitrogen.
<Tank A>
-Biuret trimer of hexamethylene diisocyanate ... 292.0g
・ Hexamethylene diisocyanate: 97.4g
・ Tribromophenyl acrylate 62.96g
-6-functional acrylate (Kyoeisha Chemical Co., UA-306H) ... 1.26 g
・ Irgacure 784 (Ciba Specialty Chemicals Co., Ltd.) ... 14g
・ 3,5 ditertiary butyl-4-hydroxytoluene ... 210mg
<Tank B>
· Poly ^{Fox TM} T (manufactured by Omnova Solutions) ··· 817.9g
-Polypropylene oxide triol (average molecular weight 1,000) ... 517.9 g
・ Tertiary butyl peroxide ・ ・ ・ 580μl
・ Dibutyl laurate tin ... 10.2g

(Comparative Example 1)
An optical recording medium was produced in the same manner as in Example 1 except that the recording layer coating solution in Example 1 was changed to a recording layer coating solution having the following composition.
<Preparation of recording layer coating solution>
A holographic recording layer coating solution having the following composition was prepared in the following tank A and tank B under a dry nitrogen atmosphere. The prepared tank was filled with dry nitrogen.
<Tank A>
-Biuret trimer of hexamethylene diisocyanate ... 292.0g
・ Hexamethylene diisocyanate: 97.4g
・ Tribromophenyl acrylate 64.22g
・ Irgacure 784 (Ciba Specialty Chemicals Co., Ltd.) ... 14g
・ 3,5 ditertiary butyl-4-hydroxytoluene ... 210mg
<Tank B>
· Poly ^{Fox TM} T (manufactured by Omnova Solutions) ··· 817.9g
-Polypropylene oxide triol (average molecular weight 1,000) ... 517.9 g
・ Tertiary butyl peroxide ・ ・ ・ 580μl
・ Dibutyl laurate tin ... 10.2g

(Comparative Example 2)
An optical recording medium was produced in the same manner as in Example 1 except that the recording layer coating solution in Example 1 was changed to a recording layer coating solution having the following composition.
<Preparation of recording layer coating solution>
A holographic recording layer coating solution having the following composition was prepared in the following tank A and tank B under a dry nitrogen atmosphere. The prepared tank was filled with dry nitrogen.
<Tank A>
-Biuret trimer of hexamethylene diisocyanate ... 292.0g
・ Hexamethylene diisocyanate: 97.4g
・ Tribromophenyl acrylate 64.22g
・ Urethane acrylate (Kyoeisha Chemical Co., Ltd., UA-306H) ... 0.06g
・ Irgacure 784 (Ciba Specialty Chemicals Co., Ltd.) ... 14g
・ 3,5 ditertiary butyl-4-hydroxytoluene ... 210mg
<Tank B>
· Poly ^{Fox TM} T (manufactured by Omnova Solutions) ··· 817.9g
-Polypropylene oxide triol (average molecular weight 1,000) ... 517.9 g
・ Tertiary butyl peroxide ・ ・ ・ 580μl
・ Dibutyl laurate tin ... 10.2g

(Comparative Example 3)
An optical recording medium was produced in the same manner as in Example 1 except that the recording layer coating solution in Example 1 was changed to a recording layer coating solution having the following composition.
<Preparation of recording layer coating solution>
A holographic recording layer coating solution having the following composition was prepared in the following tank A and tank B under a dry nitrogen atmosphere. The prepared tank was filled with dry nitrogen.
<Tank A>
-Biuret trimer of hexamethylene diisocyanate ... 292.0g
・ Hexamethylene diisocyanate: 97.4g
・ Tribromophenyl acrylate 35.03g
6-functional acrylate (manufactured by Kyoeisha Chemical Co., UA-306H) ... 29.2 g
・ Irgacure 784 (Ciba Specialty Chemicals Co., Ltd.) ... 14g
・ 3,5 ditertiary butyl-4-hydroxytoluene ... 210mg
<Tank B>
· Poly ^{Fox TM} T (manufactured by Omnova Solutions) ··· 817.9g
-Polypropylene oxide triol (average molecular weight 1,000) ... 517.9 g
・ Tertiary butyl peroxide ・ ・ ・ 580μl
・ Dibutyl laurate tin ... 10.2g

(Comparative Example 4)
An optical recording medium was produced in the same manner as in Example 1 except that the recording layer coating solution in Example 1 was changed to a recording layer coating solution having the following composition.
<Preparation of recording layer coating solution>
A holographic recording layer coating solution having the following composition was prepared in the following tank A and tank B under a dry nitrogen atmosphere. The prepared tank was filled with dry nitrogen.
<Tank A>
-Biuret trimer of hexamethylene diisocyanate ... 292.0g
・ Hexamethylene diisocyanate: 97.4g
・ Tribromophenyl acrylate ... 42.81g
・ Tetrafunctional epoxy compound (pentaerythritol tetraglycidyl ether) 21.41 g
・ Irgacure 784 (Ciba Specialty Chemicals Co., Ltd.) ... 14g
・ 3,5 ditertiary butyl-4-hydroxytoluene ... 210mg
<Tank B>
· Poly ^{Fox TM} T (manufactured by Omnova Solutions) ··· 817.9g
-Polypropylene oxide triol (average molecular weight 1,000) ... 517.9 g
・ Tertiary butyl peroxide ・ ・ ・ 580μl
・ Dibutyl laurate tin ... 10.2g

  Next, various characteristics of each recording layer coating solution (photosensitive composition) of Examples 1 to 7 and Comparative Examples 1 to 4 were evaluated as follows. The results are shown in Tables 1 and 2.

First, whether the polymerizable group of the monofunctional polymerizable compound used in the recording layer coating solution of Example 1 and the polymerizable group of the tetrafunctional or higher functional compound can be copolymerized with each other is as follows. And confirmed. The results are shown in Table 1.
<Possibility of copolymerization of polymerizable components>
In a red lamp room where light of a wavelength of 570 nm or less was completely shielded, 1 liter of ethyl acetate was poured into a three-necked flask that was shielded from light and replaced with nitrogen gas, and tribromophenyl acrylate as a monofunctional polymerizable compound. 28 g, 2.14 g of tetrafunctional acrylate (pentaerythritol tetraacrylate) and 1.4 g of Irgacure 784 (manufactured by Ciba Specialty Chemicals) as a polymerizable compound having a tetrafunctional or higher functional group were completely dissolved and sufficiently stirred. After that, the room was returned to a normal fluorescent lamp, and the flask was shielded from light and stirred for 12 hours while the flow of nitrogen gas was continued. As a result, the polymer product settled. This polymer product is taken out by filtration, polymer mass analysis is performed using a MALDI-TOF mass spectrometer (Komact DISCOVERY, manufactured by Shimadzu Corporation), and polymerization having a monofunctional polymerizable compound and a polymerizable group having 4 or more functional groups is performed. Whether or not a mass peak attributed to a copolymer with a functional compound was detected was measured.

  Next, with respect to Examples 2, 3 and Comparative Example 4, the same applies except that the monofunctional polymerizable compound and the polymerizable compound having a tetrafunctional or higher functional group are changed as shown in Table 1 below. Then, the polymer was synthesized, and it was analyzed whether a copolymer of the above two compounds was obtained. The results are shown in Table 1.

<Storage stability of recorded information>
Storage stability was evaluated through the following recording operation and forced condition processing for storage stability evaluation.
-Recording to the recording layer-
Using a collinear optical recording / reproduction evaluation apparatus (SHOT-1000, manufactured by Pulstec Industrial Co., Ltd.), information recording is performed on each of the optical recording media produced as described above under the condition that the S / N ratio of the reproduced signal is the best. And immediate regeneration. Thereafter, using a green LED mounted in advance in the evaluation apparatus, the recorded area was sufficiently exposed to lose the sensitivity to reproduction light, and information was reproduced again. The S / N ratio of the signal when immediate reproduction is performed and the S / N ratio of the signal obtained by reproduction performed after the exposure operation by the green LED are shown.

-Mandatory condition processing-
As a compulsory condition for preservability, the optical recording medium was left for 24 hours in a constant temperature room dry at 85 ° C. with sufficient light shielding.
The left optical recording medium was set in the evaluation device again to reproduce the signal. The S / N ratio of the obtained signal is shown.

* Comparative Example 4 is a combination in which the monofunctional monomer and the polyfunctional monomer are not copolymerized, as is apparent from the results in Table 1.

  From the results shown in Tables 1 and 2, each of the optical recording media of Examples 1 to 7 had a good S / N ratio after storage and could be reproduced. On the other hand, in Comparative Examples 1 to 4, the S / N ratio after storage decreased, an effective signal could not be obtained, and information could not be reproduced.

  The photosensitive composition of the present invention does not collapse the refractive index image due to volume shrinkage accompanying polymerization during information recording, is excellent in storage stability, and is used for forming a recording layer for recording information using holography, An optical recording medium having a recording layer made of the photosensitive composition can be widely used as various hologram type optical recording media capable of achieving both signal intensity and multiplexing performance, and capable of high sensitivity and high multiplexing recording.

FIG. 1 is a schematic sectional view showing an example of a conventional optical recording medium. FIG. 2 is a schematic sectional view showing another example of a conventional optical recording medium. FIG. 3 is a schematic sectional view showing an example of the optical recording medium of the present invention. FIG. 4 is a graph showing reflection characteristics with respect to incident light from the front (0 °) of a filter in which three cholesteric liquid crystal layers are laminated. FIG. 5 is a graph showing reflection characteristics with respect to incident light from a 40 ° tilt direction in a filter layer in which three cholesteric liquid crystal layers are laminated. FIG. 6 is a graph showing reflection characteristics with respect to incident light from the front (0 °) of a filter in which two cholesteric liquid crystal layers are laminated. FIG. 7 is a graph showing reflection characteristics with respect to incident light from a 20 ° tilt direction in a filter layer in which two cholesteric liquid crystal layers are laminated. FIG. 8 is an explanatory diagram showing an example of an optical system around the optical recording medium according to the present invention. FIG. 9 is a block diagram showing an example of the overall configuration of an optical recording / reproducing apparatus equipped with the optical recording medium of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 1st board | substrate 2 Reflective film 3 Servo pit pattern 4 Recording layer 5 2nd board | substrate 6 Selective reflection layer 7 2nd gap layer 8 1st gap layer 12 Objective lens 13 Dichroic mirror 14 Detector 15 1/4 wavelength plate 16 Polarizing plate 17 Half mirror 20-22 Optical recording medium 31 Pickup 33 Servo light 35 Information light and reference light 35a Information light and reference light 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 Scan unit 100 Optical recording / reproducing apparatus A Input / output surface FE Focus error signal TE Tracking error signal RF reproduction signal

Claims (10)

Containing a monofunctional polymerizable compound, a tetrafunctional or higher functional polymerizable compound, a polymerization initiator, and a polymer matrix;
The polymerizable group of the monofunctional polymerizable compound and the polymerizable group of the tetrafunctional or higher polymerizable compound can be copolymerized with each other, and the content of the tetrafunctional or higher polymerizable compound is the monofunctional polymerizable compound. 1 to 50 parts by mass with respect to 100 parts by mass of a functional polymerizable compound, which is used for forming a recording layer for recording information using holography.   The photosensitive composition according to claim 1, wherein the tetrafunctional or higher polymerizable compound has a molecular weight of 500 or more.   The photosensitive composition according to claim 1, wherein the total content of the monofunctional polymerizable compound and the tetrafunctional or higher polymerizable compound in the total solid content of the photosensitive composition is 1 to 40% by mass. .   The photosensitive composition according to any one of claims 1 to 3, wherein the content of the polymerization initiator in the total solid content of the photosensitive composition is 0.1 to 10% by mass.   The photosensitive composition according to any one of claims 1 to 4, wherein the content of the polymer matrix in the total solid content of the photosensitive composition is 60 to 99% by mass.   An optical recording medium comprising the photosensitive composition according to claim 1 and having a recording layer for recording information using holography.   The optical recording medium according to claim 6, comprising at least a first substrate, a selective reflection layer, a recording layer, and a second substrate in this order.   The optical recording medium according to claim 7, wherein the selective reflection layer transmits the first light and reflects the second light.   The optical recording medium according to claim 6 is irradiated with information light and reference light so that an optical axis of the information light and an optical axis of the reference light are coaxial, An optical recording method, wherein information is recorded on a recording layer by an interference pattern generated by interference between information light and the reference light. Light for irradiating the optical recording medium according to any one of claims 6 to 8 with the information light and the reference light so that the optical axis of the coherent information light and the optical axis of the reference light are coaxial. An optical recording apparatus comprising: irradiation means; and interference image recording means for forming an interference image due to interference between the information light and the reference light and recording the interference image on the optical recording medium.