JP2003248974A - Optical recording medium and recording / reproducing method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical recording medium which can reproduce record with recording density beyond a diffraction limit of a pickup lens unrealizable with a conventional optical disc. <P>SOLUTION: The recording medium is a compound with a structure on or/and under a recording layer for the optical recording medium arranged with a substrate and the recording layer in which four pyrrole rings which can have a substituent is coupled via a carbon atom which can have the substituent or directly coupled, and the above recording medium is arranged with a distributed layer comprising the compound in which the total number of the carbon atoms which can have the substituent connecting the four pyrrole rings is four and at least one of the pyrrole rings is directly coupled not via the carbon atom. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an information recording medium, in particular by irradiating a light beam,
The present invention relates to an optical recording medium capable of recording and reproducing information and additionally recording by causing optical changes such as transmittance and reflectance of a recording material, and a recording / reproducing method thereof.

[0002]

2. Description of the Related Art A recordable CD-compatible with the CD and DVD standards, which is an optical recording medium having a reflective layer on a substrate.
R and DVD-R have been commercialized. In the future, in such an optical recording medium, further recording capacity and miniaturization are desired, and further improvement of recording density is required. The elemental technology for improving the recording capacity in the current system includes a recording pit miniaturization technology and an image compression technology typified by MPEG2. In the technology of miniaturizing recording pits, it is considered to increase the numerical aperture NA of the optical system in order to shorten the wavelength of the recording / reproducing light and improve the diffraction limit. It is possible.

Therefore, a recording medium utilizing super-resolution capable of recording / reproducing exceeding the diffraction limit has attracted attention as an effective means.

The super-resolution is a technique for improving the resolution by making the spot diameter of the irradiation light smaller than the diffraction limit by providing an aperture at the object point that is smaller than the diffraction limit of the irradiation light.

A prior art example of an optical recording medium utilizing the technique has been shown above. As super-resolution mask material,
1) Photochromic materials, 2) Thermochromic materials, 3) Supersaturated absorption dyes, 4) Photoreactive materials, etc. have been devised. Among these, 1) photochromic material and 2) thermochromic material utilize the fact that their absorption characteristics change due to reaction by light and heat respectively, but there is a problem in stability during recording and reproduction. Particularly, one million times or more is desired for reproduction, and there is a problem in the repeated stability of the material. Furthermore, the response speed of thermochromic materials is limited to several tens of Mbps, which will be required in the future.
There is a possibility that the transfer rate of 0 Mbps or higher cannot be supported. The photoreactive material of 4) also utilizes the change in absorption characteristics due to photoreaction, but has a similar response speed.

The supersaturated absorption dye of 3) is a material whose transmittance depends non-linearly on the intensity of irradiation light, and its phenomenon is used for the intensity distribution of a laser spot to be used as a super-resolution mask. The characteristics of supersaturated absorption dyes are high response speed (which occurs in femtoseconds) and high durability. However, materials conventionally devised (previous prior art examples)
Is a phthalocyanine derivative, a naphthalocyanine derivative,
Both cyanine dyes and quinone dyes are compatible with long-wavelength lasers having a wavelength of 550 nm or more, and cannot be used with blue lasers which are considered to be the mainstream of next-generation optical recording media.

[0007]

An optical recording medium capable of recording / reproducing at a recording density exceeding the diffraction limit of a pickup lens, which cannot be realized by a conventional optical disk, is provided. 1) To provide a super resolution mask optical recording medium compatible with a blue laser. 2) To provide a super-resolution mask material that exhibits supersaturated absorption characteristics in the blue laser wavelength range.

[0008]

As a result of studies, the present inventors have found that a mask layer containing a compound having a specific structure as a main component has the above-mentioned characteristics, and have an oscillation wavelength of 400 to 550 n.
Using a semiconductor laser of m, it has been possible to obtain an optical recording medium capable of recording and reproducing at a recording density exceeding the diffraction limit and having a high transfer rate.

That is, claim 1 is a basic structure and material composition as a high density optical recording medium using the compound of the present invention, and claims 2 to 6 are optimized structure composition of porphyrin isomers as the compound. Provided, claims 7 and 8 provide a basic configuration as a super-resolution high-density optical recording medium. Claims 9 and 10 provide preferred material configurations for the super-resolution mask layer. Claim 11 provides preferred optical properties for use in the super-resolution mask layer, and claims 12 to 15 provide specific chemical structures of compounds that provide better super-resolution mask properties. Claim 16 provides a super-resolution mask recording / reproducing method limited to a blue laser wavelength.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The optical recording medium of the present invention is shown in FIG.
As shown in (a), (b) and (c), a recording layer 2 having a dispersion layer of a compound of the present invention (hereinafter, also referred to as a porphyrin isomer) on or under a substrate 1 is provided. Become. The dispersion material of the porphyrin derivative functions as a super-resolution mask, and the dispersion layer of the porphyrin isomer functions as the super-resolution reproducing layer 2 and / or the super-resolution recording layer 5. Figure 1
In (a) and (b), the super-resolution reproducing layer 2 is provided below the recording layer 3.
In addition, in FIG. 1B, the reflective layer 4 is provided on the upper side of the recording layer 3. In FIG. 1C, the super-resolution reproducing layer 2 is provided below the recording layer 3, and the super-resolution recording layer 5 is provided above the recording layer 3.

There are two viewpoints for obtaining good characteristics as a super-resolution mask layer. One is the characteristic of the recording material constituting layer, and the other is the material characteristic of obtaining the super-resolution characteristic. It is essential that the recording medium constituent layer does not change (especially deform) during recording and reproduction. When it functions as a super-resolution recording layer, the recording signal characteristics such as jitter characteristics deteriorate due to deformation, and when it functions as a super-resolution reproduction layer, the reproduction signal gradually changes and becomes stable due to deformation. No playback signal can be obtained. Therefore, in the present invention, it is preferable that the super-resolution mask layer is dispersed and fixed in a binder to reduce deformation. It is particularly preferable to firmly fix with an ultraviolet curable resin or a thermosetting resin. As a physical property of the mask material, a porphyrin isomer showing strong absorption in the emission wavelength range of a blue laser is preferable. The optical characteristics preferable as a mask material have a large absorption coefficient, and the longer the relaxation time of the excited state, the greater the supersaturation phenomenon. However, if the relaxation time is too long, it takes a long time to return to the original state, which causes trouble during repeated reproduction. Therefore, it is preferable that the absorption coefficient is 100,000 or more and the relaxation time (τ) is 1 ns ≦ τ ≦ 100 ns. As a method of lengthening the relaxation time, it is effective to introduce a heavy atom into the porphyrin derivative to increase the spin-orbit interaction. Therefore, as the structure of the porphyrin isomer, a metal porphyrin isomer in which a metal is coordinated in the center or a porphyrin derivative substituted with a heavy atom is useful. In order to increase the spin-orbit interaction sufficient as a substituent, an atom having an atomic weight of 30 or more is preferable, a halogen atom is particularly preferable, and Br and I are particularly preferable.

The method for synthesizing the porphyrin isomer of the present invention is described, for example, in Angew. Chem. Int. Ed. Eng
l. 1993, 32, No. 11, pp. 1600-1
The method described in 604 can be used.

As shown in FIG. 2, the super-resolution mask film of the dispersion layer of the porphyrin isomer thus obtained forms an optical aperture smaller than the spot diameter of the irradiation light due to the supersaturated absorption of the porphyrin isomer. . Molecules in the ground state transition to the excited state, and the relaxation time is long, so the number of molecules in the ground state decreases, the absorption amount phenomenon occurs, and the transmittance increases. Since this change is larger as the irradiation light is stronger, when the laser beam is irradiated, the transmittance changes according to its intensity distribution (Gaussian distribution). When the laser wavelength coincides with the absorption wavelength of the supersaturated absorption dye, almost no light is transmitted at the beginning of laser irradiation, and then the optical aperture is opened at the center of the beam with high light intensity (see FIG. 2).

The porphyrin isomers proposed by the present invention are
Its maximum absorption wavelength is 400 to 550 nm, which matches the oscillation wavelength of the blue laser. Therefore, the super-resolution mask film of the present invention is a super-resolution mask film suitable for a blue laser,
Higher density recording / reproducing becomes possible.

<Recording Medium Structure> The recording medium of the present invention may have a structure of a write-once optical disc (a so-called air sandwich structure in which two recording layers are provided on a substrate are bonded together), and a CD-R. It may have a structure (a recording layer, a reflective layer, a protective layer on a substrate) or a structure in which a CD-R structure is attached.

<Substrate> The substrate used must be transparent to the laser used only when recording / reproducing is performed from the substrate side, and the substrate need not be transparent when recording / reproducing is performed from the recording layer side. As the substrate material, for example, polyester, acrylic resin, polyamide, polycarbonate resin, polyolefin resin, phenol resin, epoxy resin, plastic such as polyimide, or glass,
Ceramic or metal can be used.
A guide groove for tracking, a guide pit, a preformat such as an address signal, or the like may be formed on the surface of the substrate.

<< Recording Layer >> The recording layer causes some kind of optical change by irradiation of laser light and records information by the change, and a phase change material or a recording dye is used for this recording layer. To be

Examples of the dyes include polymethine dyes, squarylium dyes, pyrylium dyes, porphyrin dyes, porphyrazine dyes, azo dyes, azomethine dyes, dyes and the like, metal complex compounds thereof, and ultraviolet absorbers. The dyes may be used alone or in combination of two or more. Further, in the above dye, a metal or a metal compound such as In, Te, Bi, Al, Be, TeO ₂ , SnO,
As, Cd, etc. can also be used in the form of dispersion mixing or lamination. Further, various materials such as polymer materials such as ionomer resin, polyamide resin, vinyl resin, natural polymer, silicone, liquid rubber, or silane coupling agent may be dispersed and mixed in the dye. For the purpose of improving properties, it may be used together with a stabilizer (for example, a transition metal complex), a dispersant, a flame retardant, a lubricant, an antistatic agent, a surfactant, a plasticizer and the like.

When the coating method is used, it is carried out by dissolving the dye or the like in an organic solvent and then using a conventional coating method such as spraying, roller coating, dipping, and spin coating. Is most preferred.

As the organic solvent, generally, alcohols such as methanol, ethanol and isopropanol, ketones such as acetone, methyl ethyl ketone and cyclohexanone, amides such as N, N-dimethylacetamide and N, N-dimethylformamide, dimethyl sulfoxide and the like. Sulfoxides, tetrahydrofuran, dioxane, diethyl ether, ethers such as ethylene glycol monomethyl ether, esters such as methyl acetate and ethyl acetate, chloroform, methylene chloride, dichloroethane,
Aliphatic halogenated carbons such as carbon tetrachloride and trichloroethane, aromatics such as benzene, xylene, monochlorobenzene and dichlorobenzene, cellosolves such as methoxyethanol and ethoxyethanol, hexane, pentane, cyclohexane and methylcyclohexane. Hydrocarbons and the like can be used.

A suitable film thickness of the recording layer is 100Å to 1 μm, preferably 200Å to 1000Å.

<< Super-Resolution Mask Layer >> Super-resolution means that the spot diameter of the irradiation light is made smaller than the diffraction limit by providing an aperture (FIG. 2) smaller than the diffraction limit of the irradiation light at the object point. As shown in FIG. 3, the super-resolution mask layer is a technique for improving the resolving power, and the super-resolution mask layer has a characteristic that the transmittance non-linearly depends on the irradiation light intensity, and this phenomenon is utilized as the super-resolution. As the super-resolution mask material, a dispersion layer of a supersaturated absorption dye, which is a porphyrin isomer represented by the following general formulas (6) to (10), is used. A structure in which a heavy atom that increases the action is introduced is preferable. Therefore, as the structure, a metal porphyrin structure in which a metal is coordinated to the center or a porphyrin isomer substituted with a heavy atom is useful, and it is particularly preferable that the substituent is an atom having an atomic weight of 30 or more, particularly a halogen atom. Atoms, especially Br, I are particularly preferred.

[Chemical 6]

[Chemical 7]

[Chemical 8]

[Chemical 9]

[Chemical 10]

Specific examples of the above halogen atom include fluorine, chlorine, bromine, iodine and the like, with bromine and iodine having a large heavy atom effect being particularly preferable.

R _{1 to} R ₈ and X _{1 to} X ₄ are each independently a hydrogen atom, a halogen atom, a nitro group, a cyano group, a hydroxyl group,
It represents a carboxyl group, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted aryl group, a substituted or unsubstituted amino group, or a substituted or unsubstituted acyl group.

Examples of the unsubstituted alkyl group and the alkyl group in the unsubstituted alkoxy group include a linear or branched alkyl group. As the substituted alkyl group and the substituted alkyl group in the substituted alkoxy group, Is a hydroxy-substituted alkyl group such as 2-hydroxyethyl group, 3-hydroxypropyl group, 4-hydroxybutyl group and 2-hydroxypropyl group; carboxy such as carboxymethyl group, 2-carboxyethyl group and 3-carboxypropyl group Substituted alkyl group; cyano-substituted alkyl group such as 2-cyanoethyl group, cyanomethyl group; amino-substituted alkyl group such as 2-aminoethyl group; 2-chloroethyl group, 3-chloropropyl group, 2-chloropropyl group, 2,2 , A halogen atom-substituted alkyl group such as 2-trifluoroethyl group; benzyl group, p-quat Robenjiru group, a phenyl-substituted alkyl group such as a 2-phenylethyl group; a 2-methoxyethyl group, 2-ethoxyethyl, 2- (n) propoxyethyl group, 2- (iso) propoxy ethyl group, 2- (n)
Butoxyethyl group, 2- (iso) butoxyethyl group,
Alkoxy-substituted alkyl groups such as 2- (2-ethylhexyloxy) ethyl group, 3-methoxypropyl group, 4-methoxybutyl group, 2-methoxypropyl group; 2- (2-
Methoxyethoxy) ethyl group, 2- (2-ethoxyethoxy) ethyl group, 2- (2- (n) propoxyethoxy) ethyl group, 2- (2- (iso) propoxyethoxy) ethyl group, 2- (2- (N) Butoxyethoxy) ethyl group, 2- (2- (iso) butoxyethoxy) ethyl group, 2- {2- (2-ethylhexyloxy) ethoxy} ethyl group and other alkoxyalkoxy-substituted alkyl groups; aryloxyethyl groups A substituted alkyl group such as a 2-phenoxyethyl group and a 2-benzyloxyethyl group;
2-acetyloxyethyl group, 2-propionyloxyethyl group, 2- (n) butyryloxyethyl group, 2-
(Iso) butyryloxyethyl group, 2-trifluoroacetyloxyethyl group or other acyloxy-substituted alkyl group; methoxycarbonylmethyl group, ethoxycarbonylmethyl group, (n) propoxycarbonylmethyl group, (i
so) propoxycarbonylmethyl group, (n) butoxycarbonylmethyl group, (iso) butoxycarbonylmethyl group, 2-ethylhexyloxycarbonylmethyl group, benzyloxycarbonylmethyl group, furfuryloxycarbonylmethyl group, tetrahydrofurfuryloxycarbonylmethyl group Group, 2-methoxycarbonylethyl group, 2-ethoxycarbonylethyl group, 2- (n) propoxycarbonylethyl group, 2- (iso) propoxycarbonylethyl group, 2- (n) butoxycarbonylethyl group, 2- (iso ) Butoxycarbonylethyl group,
Substituted or unsubstituted alkoxycarbonyl-substituted alkyl groups such as 2- (2-ethylhexyloxycarbonyl) ethyl group, 2-benzyloxycarbonylethyl group, 2-furfuryloxycarbonylethyl group; 2-methoxycarbonyloxyethyl group, 2 -Ethoxycarbonyloxyethyl group, 2- (n) propoxycarbonyloxyethyl group, 2- (iso) propoxycarbonyloxyethyl group, 2- (n) butoxycarbonyloxyethyl group, 2- (iso) butoxycarbonyloxyethyl group A substituted or unsubstituted alkoxycarbonyloxy-substituted alkyl group such as a 2- (2-ethylhexyloxycarbonyloxy) ethyl group, a 2-benzyloxycarbonyloxyethyl group, a 2-furfuryloxycarbonyloxyethyl group; Furyl, such as heterocyclic-substituted alkyl group such as tetrahydrofurfuryl group.

Examples of the cycloalkyl group include cyclopentyl group and cyclohexyl group.

The alkyl group in the alkyl group and the alkoxy group may be any alkyl group, for example, having 1 to 3 carbon atoms.
It may be 0. Specific examples of the alkyl group include:
For example: In addition, these alkyl groups may be substituted with a substituent such as a halogen atom. Methyl group, ethyl group, n-propyl group, n-butyl group, isobutyl group, n-pentyl group, neopentyl group,
Isoamyl group, 2-methylbutyl group, n-hexyl group,
2-methylpentyl group, 3-methylpentyl group, 4-methylpentyl group, 2-ethylbutyl group, n-heptyl group, 2-methylhexyl group, 3-methylhexyl group, 4
-Methylhexyl group, 5-methylhexyl group, 2-ethylpentyl group, 3-ethylpentyl group, n-octyl group, 2-methylheptyl group, 3-methylheptyl group, 4
-Methylheptyl group, 5-methylheptyl group, 2-ethylhexyl group, 3-ethylhexyl group, n-nonyl group,
Primary alkyl groups such as n-decyl group and n-dodecyl group; isopropyl group, sec-butyl group, 1-ethylpropyl group, 1-methylbutyl group, 1,2-dimethylpropyl group, 1-methylheptyl group, 1- Ethylbutyl group, 1,
3-dimethylbutyl group, 1,2-dimethylbutyl group, 1
-Ethyl-2-methylpropyl group, 1-methylhexyl group, 1-ethylheptyl group, 1-propylbutyl group, 1
-Isopropyl-2-methylpropyl group, 1-ethyl-
2-methylbutyl group, 1-propyl-2-methylpropyl group, 1-methylheptyl group, 1-ethylhexyl group,
1-propylpentyl group, 1-isopropylpentyl group, 1-isopropyl-2-methylbutyl group, 1-isopropyl-3-methylbutyl group, 1-methyloctyl group, 1-ethylheptyl group, 1-propylhexyl group,
Secondary alkyl group such as 1-isobutyl-3-methylbutyl group; tert-butyl group, tert-hexyl group, te
Tertiary alkyl groups such as rt-amyl group and tert-octyl group; cyclohexyl group, 4-methylcyclohexyl group, 4-ethylcyclohexyl group, 4-tert-butylcyclohexyl group, 4- (2-ethylhexyl) cyclohexyl group, bornyl And cycloalkyl groups such as an isobornyl group and an adamantane group.

As the aryl group, phenyl group, methylphenyl group, dimethylphenyl group, trimethylphenyl group, ethylphenyl group, tert-butylphenyl group, di (tert-butyl) phenyl group, butylphenyl group, methoxyphenyl group, Examples thereof include a dimethoxyphenyl group, a trimethoxyphenyl group and a butoxyphenyl group, and these aryl groups may be substituted with a substituent such as halogen.

In the general formulas (1) to (5), M is divalent or trivalent, which may have two hydrogen atoms, or oxygen or halogen,
Alternatively, a tetravalent metal atom, or (OR ₉ ) p, (OSi
R ₁₀ R ₁₁ R ₁₂ ) q, (OPOR ₁₃ R ₁₄ ) r, (OCOR
₁₅ ) represents a metal atom which may have s. R _{9 to} R _{15 each} independently represent a hydrogen atom, a substituted or unsubstituted aliphatic or aromatic hydrocarbon group, and p, q, r and s each represent an integer of 0 to 2.

Specifically, as M, Ib group, IIa group,
IIb group, IIIa group, IVa group, IVb group, Vb group,
There are VIb group, VIIb group and VIII group metals, oxides of these metals, halides of these metals, hydroxides of these metals, and the like, and further, the above metals have substituents.

The above metals include Cu, Zn, Mg,
Al, Ge, Ti, Sn, Pb, Cr, Mo, Mn, F
e, Co, Ni, In, Pt, Pd and the like, oxides such as TiO and VO, and halides such as AlCl, GeCl ₂ , SiCl ₂ , FeCl and Sn.
There are Cl ₂ , InCl, etc., and Al (O
H), Si (OH) ₂ , Ge (OH) ₂ , Sn (OH) ₂
Etc.

Further, when the metal has a substituent, the metal includes Al, Ti, Si, Ge, Sn and the like.
Examples of the substituent include an aryloxyl group, an alkoxyl group, a trialkylsiloxyl group, a triarylsiloxyl group, a trialkoxysiloxyl group, a triaryloxysiloxyl group, a trityloxyl group or an acyloxyl group.

The porphyrin isomer is dispersed in a binder to form a super-resolution film. As the film forming method, the porphyrin isomer and the binder may be dissolved and applied by wet coating, or the porphyrin isomer and the binder may be formed by co-evaporation by a dry film forming method. In either case, it is preferable that it does not change (especially deform) during recording and reproduction, and as the binder, an ultraviolet curable adhesive or a thermosetting adhesive that three-dimensionally crosslinks to form a strong film is preferable.

The composition of the porphyrin isomer and the binder is 1
/ 90 to 90/10 (weight ratio), if the binder is too much, the super-resolution effect is small, and if it is too small, the mechanical strength of the super-resolution mask film is impaired. 70
/ 30 (weight ratio).

The UV-curable adhesive is an adhesive which is cured by the initiation of radical polymerization upon irradiation with UV rays. Its composition is generally (1) acrylic oligomer, (2)
An acrylic monomer, (3) a photopolymerization initiator, and (4) a polymerization inhibitor. The oligomer is a polyester,
Polyurethane type, epoxy type acrylic ester, etc.
As the photopolymerization initiator, benzophenone, benzoin ether or the like can be used.

Thermosetting adhesives are adhesives that crosslink and cure when heated. Specific examples of the material include epoxy resin, oligoester acrylate, phenol resin, unsaturated polyester resin, polyimide, polyurethane, melamine resin and urea resin.

<< Undercoat Layer >> The undercoat layer has improved adhesiveness,
It is used for the purpose of barrier of water or gas, improvement of storage stability of recording layer, improvement of reflectance, protection of substrate from solvent, formation of guide groove, guide pit, preformat and the like. For the purpose of
Various polymer compounds such as ionomer resins, polyamide resins, vinyl resins, natural resins, natural polymers, silicones, liquid rubbers, and silane coupling agents can be used. In addition to materials, inorganic compounds such as SiO, MgF, SiO ₂ , T
iO, ZnO, TiN, SiN, etc., and further metal or metalloid such as Zn, Cu, Ni, Cr, Ge, S
e, Au, Ag, Al, etc. can be used. or,
For the purpose of, a metal such as Al, Au, Ag or the like, an organic thin film having a metallic luster such as a methine dye,
Examples thereof include xanthene-based dyes. For the purpose, an ultraviolet curable resin, a thermosetting resin, a thermoplastic resin, or the like can be used. The film thickness of the undercoat layer is 0.01 to 30 μm, preferably 0.05 to 10 μm.

<< Metal Reflective Layer >> The metal reflective layer may be made of a metal or a semi-metal which does not easily corrode and which has a high reflectance, and examples of the material include Au, Ag, Cr, Ni, Al and F.
e, Sn, etc., but in terms of reflectance and productivity, A
u, Ag, and Al are most preferable, and these metals and semimetals may be used alone or as an alloy of two kinds. Examples of the film forming method include vapor deposition and spattering, and the film thickness is 50 to 5000 Å, preferably 100 to 30.
It is 00Å.

<< Protective Layer, Substrate-side Hard Coat Layer >> The protective layer and the substrate-side hard coat layer protect the recording layer (reflective / absorptive layer) from scratches, dust, dirt, etc., and storage stability of the recording layer (reflective / absorptive layer). It is used for the purpose of improving the property and the reflectance. For these purposes, the materials shown for the undercoat layer can be used. Further, SiO, SiO ₂ or the like can be used as the inorganic material, and polymethyl acrylate, polycarbonate, epoxy resin, polystyrene, polyester resin, vinyl resin, cellulose, aliphatic hydrocarbon resin, natural rubber, styrene butadiene can be used as the organic material. Resin, chloroprene rubber, wax,
A heat-softening and heat-melting resin such as an alkyd resin, a drying oil and a rosin can also be used. The most preferable example of the above materials is an ultraviolet curable resin having excellent productivity. The thickness of the protective layer or the hard coat layer on the substrate surface is 0.01
-30 μm, preferably 0.05-10 μm is suitable. In the present invention, the undercoat layer, the protective layer, and the substrate surface hard coat layer, as in the case of the recording layer, a stabilizer, a dispersant, a flame retardant, a lubricant, an antistatic agent, a surfactant,
A plasticizer or the like can be included.

Next, a specific example of the porphyrin isomer will be described.

Examples of Porphyrin Isomers-Part 1-

[Chemical 11]

[0042]

[Table 1]

Example of Porphyrin Isomers-Part 2-

[Chemical 12]

[0044]

[Table 2]

Examples of Porphyrin Isomers—Part 3—

[Chemical 13]

[0046]

[Table 3]

Examples of Porphyrin Isomers—Part 4—

[Chemical 14]

[0048]

[Table 4]

Examples of Porphyrin Isomers—Part 5—

[Chemical 15]

[0050]

[Table 5]

<< Examples 1 and 2 >> Compound Examples Nos. 1 and 2 were placed on a quartz plate having a thickness of 1.0 mm. 4 and No. 14 and a chloroform solution of acrylic photopolymer (60/40% by weight) were spin-coated and then irradiated with ultraviolet rays to be cured to obtain a super-resolution mask film. For the film thickness, spin coating conditions were set so that the absorbance of the cured porphyrin isomer at the maximum absorption wavelength was ˜1.

<< Examples 3, 4, and 5 >> Compound N in Example 1
o. Instead of Compound Nos. 4 and 14, Compound No. 21,
Further, in Nos. 31 and 37, an epoxy thermosetting adhesive was used instead of the photopolymer.

Comparative Example 1 In Example 1, the compound No.
Instead of 4, a co-deposited film of polystyrene with an unsubstituted metal-free porphyrin isomer of the general formula (1) was used.

<Recording Conditions> This porphyrin-dispersed film was irradiated with a semiconductor laser beam having an oscillation wavelength of 405 nm, the transmittance when equilibrium was reached was measured, and the relationship between the laser light intensity and the transmittance was investigated.

[0055]

[Table 6] It was confirmed that any of the films had a nonlinearity in the transmittance with respect to the intensity of the blue laser light and could function as a super-resolution mask film. In addition, in comparison with porphyrins without metal substitution,
The non-linearity was stronger in the metal-coordinated porphyrin and the heavy atom-substituted porphyrin.

[0056]

As described above, according to the present invention, a super-resolution mask material exhibiting a supersaturated absorption characteristic with a high-speed response in a blue laser wavelength range and a super-resolution mask optical recording having a high transfer rate corresponding to a blue laser using the same. A medium can be provided, and an optical recording medium capable of recording / reproducing and having a high transfer rate can be provided with a recording density exceeding the diffraction limit of a pickup lens, which cannot be realized by a conventional optical disc.

According to claims 1 to 8, it is possible to provide a super-resolution mask optical information recording medium capable of high-density recording and reproduction with a laser beam in the wavelength range of 400 to 550 nm, which is higher than the diffraction limit. A preferable material constitution of the resolution mask layer can be provided. According to claim 11, preferred optical properties of the porphyrin isomer used in the super-resolution mask layer can be provided, and claims 12 to 15 can provide a specific chemical structure of the porphyrin derivative giving better super-resolution mask properties. . The sixteenth aspect can provide a super-resolution mask recording / reproducing method limited to the blue laser wavelength.

[Brief description of drawings]

1A, 1B, and 1C are explanatory views showing an example of a layer structure of an optical recording medium of the present invention.

FIG. 2 is an explanatory diagram showing formation of an optical aperture by a super-resolution mask film.

FIG. 3 is a diagram showing the relationship between incident light intensity and transmittance of a super-resolution mask film.

[Explanation of symbols]

1 substrate 2 Super-resolution reproduction layer 3 recording layers 5 Super-resolution recording layer

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Yasunobu Ueno             1-3-3 Nakamagome, Ota-ku, Tokyo Stocks             Company Ricoh (72) Inventor Noguchi Mune             1-3-3 Nakamagome, Ota-ku, Tokyo Stocks             Company Ricoh F-term (reference) 5D029 JB47 MA02 MA03 MA04                 5D090 AA01 BB03 CC01 CC04 CC14                       CC16 DD01 FF11 KK06 LL01

Claims (16)

[Claims] 1. An optical recording medium provided with a substrate and a recording layer may have a substituent on or under the recording layer.
A compound having a structure in which two pyrrole rings are directly bonded via a carbon atom which may have a substituent,
The total number of carbon atoms which may have a substituent linking two pyrrole rings is four, and at least one place is provided with a dispersion layer made of a compound in which the pyrrole rings are directly bonded without interposing carbon atoms. And an optical recording medium. 2. The optical recording medium according to claim 1, wherein the compound is a porphyrin isomer represented by the general formula (1). [Chemical 1] [Wherein R _{1 to} R ₈ and X _{1 to} X ₄ are each independently a hydrogen atom, a halogen atom, a nitro group, a cyano group, a hydroxyl group,
It represents a carboxyl group, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted aryl group, a substituted or unsubstituted amino group, or a substituted or unsubstituted acyl group. M is two hydrogen atoms,
Or a divalent, trivalent, or tetravalent metal atom which may have oxygen or halogen, or (OR ₉ ) p, (OSiR ₁₀ R
₁₁ R ₁₂ ) q, (OPOR ₁₃ R ₁₄ ) r, (OCOR ₁₅ ) s
Represents a metal atom which may have. R _{9 to} R _{15 each} independently represent a hydrogen atom, a substituted or unsubstituted aliphatic or aromatic hydrocarbon group, and p, q, r and s each represent an integer of 0 to 2. ] 3. The optical recording medium according to claim 1, wherein the compound is a porphyrin isomer represented by the general formula (2). [Chemical 2] [Wherein R _{1 to} R ₈ and X _{1 to} X ₄ are each independently a hydrogen atom, a halogen atom, a nitro group, a cyano group, a hydroxyl group, a carboxyl group, a substituted or unsubstituted alkyl group, a substituted or unsubstituted It represents an alkoxy group, a substituted or unsubstituted aryl group, a substituted or unsubstituted amino group, or a substituted or unsubstituted acyl group. M is two hydrogen atoms, or a divalent, trivalent, or tetravalent metal atom which may have oxygen or halogen, or (OR ₉ ) p, (OSiR ₁₀ R ₁₁
R ₁₂ ) q, (OPOR ₁₃ R ₁₄ ) r, and (OCOR ₁₅ ) s represent a metal atom which may have. R _{9 to} R _{15 each} independently represent a hydrogen atom, a substituted or unsubstituted aliphatic or aromatic hydrocarbon group, and p, q, r and s each represent an integer of 0 to 2. ] 4. The optical recording medium according to claim 1, wherein the compound is a porphyrin isomer represented by the general formula (3). [Chemical 3] [Wherein R _{1 to} R ₈ and X _{1 to} X ₄ are each independently a hydrogen atom, a halogen atom, a nitro group, a cyano group, a hydroxyl group, a carboxyl group, a substituted or unsubstituted alkyl group, a substituted or unsubstituted It represents an alkoxy group, a substituted or unsubstituted aryl group, a substituted or unsubstituted amino group, or a substituted or unsubstituted acyl group. M is two hydrogen atoms, or a divalent, trivalent, or tetravalent metal atom which may have oxygen or halogen, or (OR ₉ ) p, (OSiR ₁₀ R ₁₁
R ₁₂ ) q, (OPOR ₁₃ R ₁₄ ) r, and (OCOR ₁₅ ) s represent a metal atom which may have. R _{9 to} R _{15 each} independently represent a hydrogen atom, a substituted or unsubstituted aliphatic or aromatic hydrocarbon group, and p, q, r and s each represent an integer of 0 to 2. ] 5. The optical recording medium according to claim 1, wherein the compound is a porphyrin isomer represented by the general formula (4). [Chemical 4] [Wherein R _{1 to} R ₈ and X _{1 to} X ₄ are each independently a hydrogen atom, a halogen atom, a nitro group, a cyano group, a hydroxyl group, a carboxyl group, a substituted or unsubstituted alkyl group, a substituted or unsubstituted It represents an alkoxy group, a substituted or unsubstituted aryl group, a substituted or unsubstituted amino group, or a substituted or unsubstituted acyl group. M is two hydrogen atoms, or a divalent, trivalent, or tetravalent metal atom which may have oxygen or halogen, or (OR ₉ ) p, (OSiR ₁₀ R ₁₁
R ₁₂ ) q, (OPOR ₁₃ R ₁₄ ) r, and (OCOR ₁₅ ) s represent a metal atom which may have. R ₉ ~R1 ₁₅ is independently a hydrogen atom, an aliphatic substituted or unsubstituted, an aromatic hydrocarbon group, p, q, r, s represents an integer of 0 to 2. ] 6. The optical recording medium according to claim 1, wherein the compound is a porphyrin isomer represented by the general formula (5). [Chemical 5] [Wherein R _{1 to} R ₈ and X _{1 to} X ₄ are each independently a hydrogen atom, a halogen atom, a nitro group, a cyano group, a hydroxyl group, a carboxyl group, a substituted or unsubstituted alkyl group, a substituted or unsubstituted It represents an alkoxy group, a substituted or unsubstituted aryl group, a substituted or unsubstituted amino group, or a substituted or unsubstituted acyl group. M is two hydrogen atoms, or a divalent, trivalent, or tetravalent metal atom which may have oxygen or halogen, or (OR ₉ ) p, (OSiR ₁₀ R ₁₁
R ₁₂ ) q, (OPOR ₁₃ R ₁₄ ) r, and (OCOR ₁₅ ) s represent a metal atom which may have. R _{9 to} R _{15 each} independently represent a hydrogen atom, a substituted or unsubstituted aliphatic or aromatic hydrocarbon group, and p, q, r and s each represent an integer of 0 to 2. ] 7. The super-resolution reproducing layer provided above or below the recording layer, wherein the dispersion layer is a super-resolution reproducing layer.
The optical recording medium according to any one of 1. 8. The optical recording medium according to claim 1, wherein the dispersion layer is a super-resolution recording layer provided both above and below the recording layer. 9. The optical recording medium according to claim 1, wherein the dispersion layer comprises a porphyrin isomer and an ultraviolet curable resin. 10. The optical recording medium according to claim 1, wherein the dispersion layer comprises a porphyrin isomer and a thermosetting resin. 11. The molecular extinction coefficient of the compound at a recording / reproducing wavelength is 100,000 or more, and the relaxation time τ is 1 ns.
≦ τ ≦ 100 ns, in any one of claims 1 to 10,
The optical recording medium described. 12. The optical recording medium according to claim 1, wherein the compound is a metalloporphyrin isomer. 13. The optical recording medium according to claim 1, wherein the compound is substituted with a heavy atom having an atomic weight of 30 or more. 14. The optical recording medium according to claim 13, wherein the substituent is a halogen atom. 15. The optical recording medium according to claim 14, wherein the substituent is Br or I. 16. The recording / reproducing method for an optical recording medium according to claim 1, wherein recording / reproducing is performed by using a laser beam having a wavelength of 400 nm to 550 nm to increase the transmittance of the central portion of the laser beam of the dispersion layer.