JP2002166648A - Optical recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical recording medium using a styryl pigment, adaptable to a DVD-R disk system and having high light fastness and storage stability. SOLUTION: In the optical recording medium wherein a recording layer is provided on a substrate, the recording layer contains at least the styryl pigment and an azo metal chelate compound consisting of an azo compound represented by general formula (I) and a metal.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a large-capacity write-once optical disk for data, such as a large-capacity write-once compact disc, DVD-R, and a technique applied to a large-capacity optical card.

[0002]

2. Description of the Related Art At present, as a next-generation large capacity optical disk,
The development of VD-R is underway. As elemental technologies for improving the recording capacity, development of recording materials for miniaturizing recording pits, adoption of image compression technology represented by MPEG2, semiconductor laser for reading recording pits Technology development such as shortening of wavelength is required.

Hitherto, as a semiconductor laser in the red wavelength region, a 670 nm band Al has been used for bar code readers and measuring instruments.
Although only GaInP laser diodes have been commercialized, red lasers are being used in the optical storage market in earnest as the density of optical disks increases. DVD
In the case of a drive, the light source is standardized by the wavelength of a laser diode in a 630 nm to 670 nm band.

[0004] Under these circumstances, the most preferable DVD-
The R medium is a medium capable of recording and reproducing at a wavelength of 630 to 670 nm. However, a recording material which is excellent in light resistance and storage stability and which can be recorded and reproduced by an optical pickup using a laser of 670 nm or less has not yet been developed.

[0005]

SUMMARY OF THE INVENTION Wavelengths of 630 to 670n
As one of optical recording media for recording / reproducing with an optical pickup using a laser of m, a medium containing a styryl dye can be cited (for example, JP-A-11-99747), but this dye is remarkably deteriorated in light and has poor stability. . In addition, azo metal chelate dyes may be mentioned as dyes exhibiting high light resistance,
Media using this dye for the recording layer had problems such as low reflectance.

[0006] The present invention has been made in view of such circumstances, and uses a styryl dye especially applicable to a DVD-R disk system using a semiconductor laser having an oscillation wavelength shorter than that of the conventional system. An object of the present invention is to provide an optical recording medium having improved light resistance and storage stability.

[0007]

Means for Solving the Problems The present inventors have studied the above problems and found that the recording layer was formed using a mixture of a styryl dye and an azo metal chelate compound having a specific structure, so that an oscillation wavelength of 670 nm was obtained. The present inventors have found that an optical recording medium which can be applied to the next-generation large-capacity optical disk system using the following semiconductor lasers and has excellent light resistance and storage stability can be obtained, and has reached the present invention. That is,
According to the present invention, first, in an optical recording medium having a recording layer on a substrate, the recording layer comprises at least a styryl dye, an azo compound represented by the following general formula (I) and an azo metal chelate compound And an optical recording medium characterized by comprising:

Embedded image (Wherein, R ₁ and R ₂ each independently represent a hydrogen atom, a halogen atom, a nitro group, a cyano group, a hydroxyl group, a carboxyl group,
Amino group, carbamoyl group, substituted or unsubstituted alkyl group, substituted or unsubstituted aryl group, substituted or unsubstituted heterocyclic residue, substituted or unsubstituted alkyloxy group, substituted or unsubstituted aryloxy group, Substituted or unsubstituted alkylthio group, substituted or unsubstituted arylthio group, substituted or unsubstituted alkylamino group, substituted or unsubstituted arylamino group, substituted or unsubstituted alkyloxycarbonyl group, substituted or unsubstituted aryl Represents an oxycarbonyl group, a substituted or unsubstituted alkylcarboxamide group, a substituted or unsubstituted arylcarboxamide, a substituted or unsubstituted alkylcarbamoyl group, a substituted or unsubstituted arylcarbamoyl group, or a substituted or unsubstituted alkenyl group. R _{3 to} R ₆ are the same as R ₁ and R ₂ . Z represents a hydroxyl group, a carboxyl group, an amino group, an alkylcarboxamide group, an arylcarboxamide group, an alkylsulfonamide group, an arylsulfonamide group, a carbamoyl group, an alkylcarbamoyl group, an arylcarbamoyl group, a sulfo group, a sulfino group, or a sulfamoyl group. . )

Second, in the optical recording medium described in the first aspect, the recording layer contains a styryl dye and an azo metal chelate compound in a weight ratio of 90:10 to 20:80. An optical recording medium is provided.

Third, the optical recording medium according to the first or second aspect, wherein the metal atom of the azo metal chelate compound is any of manganese, cobalt, nickel, and copper. Is provided.

Fourth, there is provided an optical recording medium according to the first or second aspect, wherein the styryl dye is represented by the following general formula (II).

Embedded image (In the formula, A represents a ring obtained by condensing a substituted or unsubstituted pyrrole ring, oxazole ring, thiazole ring, selenazole ring, pyridine ring, or imidazole ring with a benzene ring or a naphthalene ring. In the ring, when the nitrogen atom has a charge of +1 valence, it contains a -1 valent counter ion or a -1 valent group in the Y part, where Y is the same as R ₁ and R _2, and n is 1 to 3 Represents an integer.)

Fifth, in the optical recording medium according to any one of the first to fourth aspects, the refractive index n of the single recording layer with respect to light in a wavelength range of recording / reproducing wavelength ± 5 nm is 1.5 ≦ n.
≦ 3.0 and an extinction coefficient k of 0.02 ≦ k ≦ 0.2 is provided.

Sixth, in the optical recording medium according to any one of the above first to fifth aspects, when the optical recording medium is provided with a reflective layer, the reflective layer is made of gold, silver, copper, aluminum, or any of these metals. An optical recording medium is provided which is one of alloys containing two or more kinds.

Seventh, in the optical recording medium according to any one of the first to sixth aspects, the track pitch on the substrate is 0.7 to 0.8 μm, the groove width is half width, 0.18 to 0.8 μm.
An optical recording medium having a diameter of 0.40 μm is provided.

Eighth, in the optical recording medium according to any one of the first to seventh aspects, the optical recording medium has a recording wavelength of 60.
An optical recording medium characterized by being used in the range of 0 to 720 nm is provided.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail.
The optical recording medium of the present invention contains a styryl dye and an azo metal chelate compound composed of an azo compound represented by the general formula (I) and a metal in a recording layer, and the styryl dye: azo metal chelate compound is contained in a weight ratio. 90:10 to 10: 9
0, preferably in a ratio of 80:20 to 40:60. By adding the azo metal chelate compound at such a ratio to the styryl dye, photodeterioration of the styryl dye is prevented, and an optical recording medium having excellent light resistance is obtained. On the other hand, if the amount of styryl dye exceeds the upper limit, the effect of the azo metal chelate compound is reduced, and sufficient light resistance cannot be obtained. On the other hand, when the amount of styryl dye is less than the above range, there are problems such as a decrease in reflectance.

The azo compound of the general formula (I) is as described above. In the formula, specific examples of the alkyl group for R ₁ and R ₂ include a methyl group, an ethyl group, an n-propyl group, an n-butyl group, an n-pentyl group, an n-hexyl group, an n-heptyl group, and an n-octyl. Groups, primary alkyl groups such as n-nonyl group, n-decyl group, isobutyl group, isoamyl group, 2-methylbutyl group, 2-methylpentyl group, 3-methylpentyl group, 4-methylpentyl group, 2-ethylbutyl group ,
2-methylhexyl group, 3-methylhexyl group, 4-methylhexyl group, 5-methylhexyl group, 2-ethylpentyl group, 3-ethylpentyl group, 2-methylheptyl group, 3-methylheptyl group, 4- Methylheptyl group, 5
-Methylheptyl group, 2-ethylhexyl group, 3-ethylhexyl group, isopropyl group, sec-butyl group,
-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-methyl Octyl group, 1-ethylheptyl group, 1-propylhexyl group, secondary alkyl group such as 1-isobutyl-3-methylbutyl group, netopentyl group, tert-butyl group, tert-hexyl group, tert-amino group, te
tertiary alkyl groups such as rt-octyl group, cyclohexyl group, 4-methylcyclohexyl group, 4-ethylcyclohexyl group, 4-tert-butylcyclohexyl group, 4
And cycloalkyl groups such as-(2-ethylhexyl) cyclohexyl group, bornyl group, isobornyl group (adamantyl group) and the like.

Further, these primary and secondary alkyl groups include a hydroxyl group, a halogen atom, a nitro group, a carboxyl group, a cyano group, a substituted or unsubstituted aryl group, and a substituted or unsubstituted heterocyclic residue. It may be replaced. Further, the alkyl group may be substituted through an atom such as oxygen, sulfur, or nitrogen. Examples of the alkyl group substituted via oxygen include a methoxymethyl group, a methoxyethyl group, a phenoxyethyl group, a methoxypropyl group, an ethoxypropyl group, a piperidino group, and a morpholino group. Examples of the alkyl group in which a methylthioethyl group, an ethylthioethyl group, an ethylthiopropyl group, a phenylthioethyl group, and the like are substituted via nitrogen include a dimethylaminoethyl group, a diethylaminoethyl group, and a diethylaminopropyl group. And the like.

Specific examples of the aryl group include a phenyl group, a naphthyl group, an anthranyl group, a fluorenyl group, a phenalenyl group, a phenanthranyl group, a triphenylenyl group, a pyrenyl group and the like. Further, these aryl groups may be substituted with a hydroxyl group, a halogen atom, a nitro group, a carboxyl group, a cyano group, a substituted or unsubstituted aryl group, a substituted or unsubstituted heterocyclic residue, and the like. Further, it may be substituted with the above-mentioned alkyl group via an atom such as oxygen, sulfur and nitrogen.

Specific examples of the heterocyclic residue include furyl, thienyl, pyrrolyl, benzofuryl, isobenzofuranyl, benzothienyl, indolinyl, isoindolinyl, carbazolyl, pyridyl, piperidyl, quinolyl. Group, isoquinolyl group, oxazolyl group, isoxazolyl group, thiazolyl group, isothiazolyl group, imidazolyl group, pyrazolyl group, benzimidazolyl group, pyrazyl group, pyrimidyl group, pyridazinyl group, quinosalinyl group and the like. Further, these aryl groups may be substituted with a hydroxyl group, a halogen atom, a nitro group, a carboxyl group, a cyano group, a substituted or unsubstituted aryl group, a substituted or unsubstituted heterocyclic residue, Further, it may be substituted with the above-mentioned alkyl group via an atom such as oxygen and sulfur. Specific examples of the halogen atom include fluorine, chlorine, bromine, iodine and the like.

The alkyloxy group may be any one in which a substituted or unsubstituted alkyl group is directly bonded to an oxygen atom, and specific examples of the alkyl group include the aforementioned specific examples. The aryloxy group may be any one in which a substituted or unsubstituted aryl group is directly bonded to an oxygen atom, and specific examples of the aryl group include the specific examples described above. The alkylthio group may be any one in which a substituted or unsubstituted alkyl group is directly bonded to a sulfur atom, and specific examples of the alkyl group include the aforementioned specific examples. The arylthio group may be one in which a substituted or unsubstituted aryl group is directly bonded to a sulfur atom, and specific examples of the aryl group include the specific examples described above. The alkylamino group may be any one in which a substituted or unsubstituted alkyl group is directly bonded to a nitrogen atom, and specific examples of the alkyl group include the specific examples described above.
Further, the alkyl groups may be bonded to each other to form a ring such as a piperidino group, a morpholino group, a pyrrolidinyl group, a piperazinyl group, an indolinyl group, an isoindolinyl group, and the like. The arylamino group may be any one in which a substituted or unsubstituted aryl group is directly bonded to a nitrogen atom, and specific examples of the aryl group include the specific examples described above. The alkyloxycarbonyl group may be any one in which a substituted or unsubstituted alkyl group is directly bonded to an oxygen atom, and specific examples of the alkyl group include the aforementioned specific examples. The aryloxycarbonyl group may be any one in which a substituted or unsubstituted aryl group is directly bonded to an oxygen atom, and specific examples of the aryl group include the specific examples described above.
The alkylcarboxamide group may be any one in which a substituted or unsubstituted alkyl group is directly bonded to a carbon atom, and specific examples of the alkyl group include the aforementioned specific examples. The arylcarboxamide group may be any one in which a substituted or unsubstituted aryl group is directly bonded to a carbon atom, and specific examples of the aryl group include the aforementioned specific examples. The alkylcarbamoyl group may be any one in which a substituted or unsubstituted alkyl group is directly bonded to a nitrogen atom, and specific examples of the alkyl group include the aforementioned specific examples. Further, the alkyl groups may be bonded to each other to form a ring such as a piperidino group, a morpholino group, a pyrrolidinyl group, a piperazinyl group, an indolinyl group, an isoindolinyl group, and the like. The arylcarbamoyl group may be any one in which a substituted or unsubstituted aryl group is directly bonded to a nitrogen atom, and specific examples of the aryl group include the aforementioned specific examples.

R _{3 to} R ₆ are selected from the substituents of R ₁ and R _{2 described} above.

Further, specific examples of the alkylsulfonamide group in Z may be those in which a substituted or unsubstituted alkyl group is directly bonded to a sulfur atom, and specific examples of the alkyl group include those described above. Can be mentioned. Specific examples of the arylsulfonamide group may be those in which a substituted or unsubstituted aryl group is directly bonded to a sulfur atom, and specific examples of the aryl group include the aforementioned specific examples.

The metal atoms forming a metal chelate with the azo compound are, for example, aluminum, titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc,
Examples include zirconium, niobium, molybdenum, technetium, ruthenium, rhodium, and palladium, and azo metal chelate compounds of manganese, cobalt, nickel, and copper have excellent optical properties as optical recording materials.

According to the present invention, the recording / reproducing wavelength ranges from 600 to 72.
It is characterized by using a laser beam of 0 nm, but from the optical characteristics at this wavelength, those represented by the general formula (II) are preferable among styryl dyes.

In the general formula (II), A represents a ring in which a substituted or unsubstituted pyrrole ring, oxazole ring, thiazole ring, selenazole ring, pyridine ring, or imidazole ring is fused with a benzene ring or a naphthalene ring. . In particular, when the nitrogen atom in the ring of the above A has a +1 valence charge, a -1 valence counter ion or a -1 valence group is contained in the Y portion. Y represents a substituent directly bonded to the benzene ring. Specific examples of the monovalent counter ion include I ⁻ , ClO ₄ ⁻ ,
BF ₄ ⁻ , PF ₆ ⁻ , SbF ₆ ⁻ , p-toluenesulfonic acid ion and the like. Specific examples of the monovalent group include an O ^- group, a COO ^- group, and S
O ₃ ^- group and the like. Further, specific examples of Y are selected from the specific examples of the substituents of R ₁ and R _{2 described} above.

Next, the configuration of the optical recording medium will be described. First, optical characteristics are listed as items necessary for forming the recording layer. The condition required for the optical characteristics is that the recording / reproducing wavelength has a large absorption band on the shorter wavelength side with respect to the recording / reproducing wavelength of 630 nm to 690 nm, and the recording / reproducing wavelength is near the long wavelength end of the absorption band. is there. This means that it has a large refractive index and a large extinction coefficient at a recording / reproducing wavelength of 630 nm to 690 nm.

More specifically, the refractive index n of the single recording layer with respect to light in the wavelength range near the long wavelength near the recording / reproducing wavelength is 1.5 or more and 3.0 or less, and the extinction coefficient k is 0.02 or more. 0.2
When n is less than 1.5, it is difficult to obtain a sufficient optical change, so that the recording modulation degree becomes low, which is not preferable. When n is more than 3.0, Is not preferable because the wavelength dependency becomes too high and an error occurs even in the recording / reproducing wavelength region. When k is less than 0.02, the recording sensitivity deteriorates, which is not preferable. When k is more than 0.2, it is difficult to obtain a reflectance of 50% or more, which is not preferable.

The conditions required for the substrate shape are as follows: the track pitch on the substrate is 0.7 to 0.8 μm, and the groove width is a half value width of 0.18 to 0.40 μm. The substrate usually has a guide groove with a depth of 1000 to 2500 °. The track pitch is usually 0.7 to 1.0 μm, but preferably 0.7 to 0.8 μm for high capacity applications. The groove width is
The half width is preferably 0.18 to 0.36 μm. 0.18
If it is less than μm, it may be difficult to obtain a sufficient tracking error signal intensity. On the other hand, when the thickness exceeds 0.36 μm, the recording portion tends to spread laterally when recording is performed, which is not preferable.

Structure of Recording Medium The recording medium of the present invention is a conventional write-once optical disc having the structure shown in FIG. 1 (a so-called air sandwich or close-adhesion structure in which two sheets of FIG. 1 are bonded) and FIG. The medium may be a CD-R medium having the above structure.

Examples of Necessary Properties and Constituent Materials of Each Layer The basic structure of the recording medium of the present invention is a structure in which a first substrate and a second substrate are bonded with an adhesive via a recording layer. The recording layer may be a single layer of an organic dye layer, or may be a laminate of an organic dye layer and a metal reflective layer to increase the reflectance.
The recording layer and the substrate may be configured with an undercoat layer or a protective layer interposed therebetween, or may be formed by laminating them for improving the function. The most commonly used structure is a first substrate / organic dye layer / metal reflective layer / protective layer / adhesive layer / second substrate structure.

Substrate As a necessary characteristic of the substrate, the substrate must be transparent to the laser beam used only when recording and reproduction are performed from the substrate side. When recording and reproduction are performed from the recording layer side, the substrate needs to be transparent. Absent. Therefore, according to the present invention, when only one layer of the substrate is used, if only the second substrate is transparent, the first substrate is used.
The substrate may be transparent or opaque. As a substrate material,
For example, plastics such as polyester, acrylic resin, polyamide, polycarbonate resin, polyolefin resin, phenol resin, epoxy resin, and polyimide, glass, ceramic, and metal can be used.
When only one substrate is used, or when two substrates are used in a sandwich shape, a guide groove or a guide pit for tracking and a preformat such as an address signal are formed on the surface of the first substrate. May be.

Recording Layer The recording layer is capable of causing some optical change by laser beam irradiation and recording information by the change. The recording layer contains the dye mixture of the present invention. is necessary. In forming the recording layer, the dyes of the present invention may be used alone or in combination of two or more. Further, the dye of the present invention has optical properties, recording sensitivity,
It may be mixed or laminated with other organic dyes, metals, and metal compounds for the purpose of improving signal characteristics and the like. Examples of organic dyes include polymethine dyes, naphthalocyanine, phthalocyanine, squarylium, croconium, pyrylium, naphthoquinone, anthraquinone (indanthrene), xanthene, triphenylmethane, azulene, and tetrahydrocholine. System, phenanthrene system,
Examples include a triphenothiazine dye and a metal chelate compound, and the above-mentioned dyes may be used alone or in combination of two or more.

Further, metals and metal compounds such as In, Te, Bi, Se, Sb, Ge, Sn, A
i, Be, TeO ₂ , SnO, As, Cd and the like can be used in the form of dispersion mixing or lamination. Further, various materials such as a polymer material, for example, an ionomer resin, a polyamide resin, a vinyl resin, a natural polymer, silicone, and a liquid rubber, or a silane coupling agent or the like are dispersed and mixed in the dye. 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 for the purpose of improving properties.

The recording layer is formed by vapor deposition, sputtering,
It can be performed by ordinary means such as CVD or solution coating. When the coating method is used, the dye or the like is dissolved in an organic solvent or the like, and the coating is performed by a conventional coating method such as spraying, roller coating, dipping, or spin coating. Examples of the organic solvent used include alcohols such as methanol, ethanol, and isopropanol; ketones such as acetone, methyl ethyl ketone and cyclohexanone; amides such as N, N-dimethylformamide and N, N-dimethylacetamide; and dimethyl sulfoxide. Sulfoxides, tetrahydrofuran, dioxane, diethyl ether, ethers such as ethylene glycol monomethyl ether, methyl acetate,
Esters such as ethyl acetate, aliphatic halogenated hydrocarbons such as chloroform, methylene chloride, dichloroethane, carbon tetrachloride, and trichloroethane; or aromatics such as benzene, xylene, monochlorobenzene, and dichlorobenzene; methoxyethanol and ethoxyethanol Such as cellosolves, hexane, pentane, cyclohexane,
Hydrocarbons such as methylcyclohexane can be used. The thickness of the recording layer is 100 ° to 10 μm, preferably 200 ° to 2000 °.

Undercoat Layer The undercoat layer comprises (a) an improvement in adhesion, (b) a barrier against water or gas, (c) an improvement in storage stability of the recording layer,
It is used for the purpose of (d) improving the reflectance, (e) protecting the substrate and the recording layer from a solvent, and (f) forming guide grooves, guide pits, preformats, and the like. For the purpose of (a), polymer materials, for example, various polymer materials such as ionomer resins, polyamide resins, vinyl resins, natural resins, natural polymers, silicones, liquid rubbers, and silane coupling agents are used. It can be used, and for the purposes of (b) and (c), besides the above-mentioned polymer materials, inorganic compounds such as SiO ₂ , MgF ₂ , SiO, TiO ₂ , ZnO, Ti
N, SiN, and other metals or metalloids such as Zn, Cu,
Ni, Cr, Ge, Se, Au, Ag, Al and the like can be used. For the purpose of (d), metal,
For example, an organic thin film having a metallic luster such as Al, Ag or the like, for example, a methine dye, a xanthene dye, or the like can be used. For the purposes (e) and (f), an ultraviolet curable resin, a thermosetting resin, a thermoplastic resin, or the like can be used. The thickness of the undercoat layer is 0.01 to 30 μm, preferably 0.05 to 10 μm.

Metal reflective layer The reflective layer is a single metal which is highly resistant to corrosion and can provide high reflectance.
Semimetals and the like; examples of materials include Au, Ag, and C;
r, Ni, Al, Fe, Sn, Cu and the like. Au, Ag, Al, and Cu are most preferable in terms of reflectivity and productivity, and these metals and metalloids may be used alone or as two or more alloys. As a film formation method,
For example, vapor deposition, sputtering, etc. may be used.
５5000Å, preferably 100〜3000Å.

Protective Layer, Substrate Hard Coat Layer The protective layer or the substrate hard coat layer (a) protects the recording layer (reflection / absorption layer) from scratches, dust, dirt, and the like.
(B) improvement in storage stability of the recording layer (reflection / absorption layer),
(C) Used for the purpose of improving the reflectance. For these purposes, the materials shown in the undercoat layer can be used. Further, as the inorganic material, SiO, SiO
₂ etc. can also be used. Organic materials include polymethyl acrylate, polycarbonate, epoxy resin,
Heat softening and heat of polystyrene, polyester resin, vinyl resin, cellulosic resin, aliphatic hydrocarbon resin, aromatic hydrocarbon resin, natural rubber, styrene butadiene resin, chloroprene rubber, wax, alkyd resin, drying oil, rosin, etc. Melting resins can also be used. Among the above materials, the most preferable example of the protective layer or the hard coat layer on the substrate surface is an ultraviolet curable resin having excellent productivity. The thickness of the protective layer or the hard coat layer on the substrate surface is
It is 0.01 to 30 μm, preferably 0.05 to 10 μm. 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 and the like can be contained.

Protective Substrate The protective substrate must be transparent to the laser light to be used when irradiating laser light from this protective substrate. Transparency does not matter when used as a mere protective plate. The usable substrate material is exactly the same as the above-mentioned substrate material, and it is possible to use polyester, acrylic resin, polyamide, polycarbonate resin, polyolefin resin, phenol resin, epoxy resin, plastic such as polyimide, glass, ceramic or metal. Cut with

Adhesive, Adhesive Layer Any material capable of adhering two recording media may be used, and from the viewpoint of productivity, an ultraviolet-curable or hot-melt adhesive is preferable.

[0040]

Next, the present invention will be described in more detail by way of examples. However, the present invention is not limited by the following examples.

Example 1 Compounds A-3 and B-1 were placed on a 0.6 mm thick injection molded polycarbonate substrate having a guide groove with a groove depth of 1750 °, a half width of 0.25 μm, and a track pitch of 0.74 μm.
(See Table 1-1 and Table 2-1).
Is dissolved in 2,2,3,3-tetrafluoropropanol, and the solution is applied with a spinner to a thickness of 100
An organic dye layer of 0 ° was formed, and then a reflective layer of 1300 ° of silver was provided by a sputtering method, and a 5 μm protective layer of an acrylic photopolymer was provided thereon. Furthermore, the thickness is 0.
A 6 mm injection polycarbonate substrate was bonded with an acrylic photopolymer to obtain a recording medium.

Examples 2 to 10 Recording media were formed in exactly the same manner as in Example 1 using dyes having the combinations shown in Table 3.

Comparative Example 1 A recording medium was formed in the same manner as in Example 1 except that only the styryl dye of Compound Example B-3 (Table 2-1) was used.

Evaluation Method and Evaluation Results Using the semiconductor laser light having an oscillation wavelength of 658 nm and a beam diameter of 1.0 μm for each of the recording media of the examples and comparative examples obtained as described above, a signal (linear velocity of 3.5 m / sec. s
ec) was recorded and reproduced with continuous light (reproduction power 0.7 mW) of a semiconductor laser having an oscillation wavelength of 658 nm, and a reproduction waveform was observed. Further, a light fastness test and a storage test were performed under the following conditions. Table 3 shows the results. Light fastness test conditions: 40,000 Lux, Xe light, continuous irradiation for 20 hours Storage test conditions: 50 ° C., 80% RH, left for 800 hours

[0045]

[Table 1]

[0046]

[Table 2]

[0047]

[Table 3]

[0048]

[Table 4]

[0049]

[Table 5]

[0050]

[Table 6]

[0051]

As described above, according to the first aspect of the present invention, in an optical recording medium having a recording layer on a substrate, the recording layer comprises at least a styryl dye, an azo compound represented by the general formula (I), and a metal. And an azo metal chelate compound of the formula (1), whereby an optical recording medium capable of recording and reproducing with a laser beam having a wavelength of 670 nm or less, and having excellent light resistance and storage stability can be obtained.

According to a second aspect of the present invention, in the recording layer, a styryl dye and an azo metal chelate compound are contained in a weight ratio of 90:10 to 10:10.
Since it is contained at a ratio of 20:80, optical degradation of the styryl dye is prevented, and an optical recording medium having excellent light resistance and favorable reflectance can be obtained.

According to a third aspect of the present invention, the metal atom of the azo metal chelate compound is manganese, cobalt, nickel,
Since it is any one of copper, optimal optical characteristics as an azo metal chelate dye can be obtained.

According to the invention of claim 4, since the styryl dye is represented by the general formula (II), excellent optical characteristics can be obtained by the laser light having a recording / reproducing wavelength of 600 to 720 nm in the present invention.

According to a fifth aspect of the present invention, in the optical recording medium, the refractive index n of the recording layer single layer with respect to light in a wavelength range of recording / reproducing wavelength ± 5 nm is 1.5 ≦ n ≦ 3.0, and the extinction coefficient is k
Is 0.02 ≦ k ≦ 0.2, it is possible to obtain an optical recording medium capable of recording and reproducing with high reflectance and high modulation.

According to a sixth aspect of the present invention, when the optical recording medium is provided with a reflective layer, the reflective layer is any one of gold, silver, copper, aluminum and an alloy containing two or more of these metals. An optimal reflective layer for high-density media can be obtained.

According to a seventh aspect of the present invention, in the optical recording medium, the track pitch on the substrate is 0.7 to 0.8 μm,
Since the groove width is a half value width of 0.18 to 0.40 μm, it is possible to obtain an optimal substrate guide groove for high-density media.

According to the eighth aspect of the present invention, since the optical recording medium is used in a recording wavelength range of 600 to 720 nm,
Recording and reproduction can be performed at an optimum recording wavelength for high-density media.

[Brief description of the drawings]

FIGS. 1A to 1D are cross-sectional views illustrating a configuration example of a normal write-once optical recording medium.

FIGS. 2A to 2C are cross-sectional views illustrating a configuration example of an optical recording medium for CD-R.

FIGS. 3A to 3C are cross-sectional views illustrating a configuration example of an optical recording medium for DVD-R.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Substrate 2 Recording layer 3 Undercoat layer 4 Protective layer 5 Hard coat layer 6 Metal reflective layer 7 Protective substrate 8 Adhesive layer

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification FI FI Theme Court ゛ (Reference) G11B 7/24 516 G11B 7/24 522A 522 561N 561 B41M 5/26 Y (72) Inventor Tatsuya Tomura Tokyo 1-3-6 Nakamagome, Ota-ku Ricoh Co., Ltd. F-term (reference) 2H111 EA03 EA12 EA22 EA48 FA12 FA23 FB42 4H056 CA03 CC02 CE02 CE03 DD03 DD04 DD19 DD23 DD30 FA06 5D029 JA04 JB47 JC05 MA13 WB11 WB14

Claims (8)

[Claims] 1. An optical recording medium having a recording layer on a substrate, wherein the recording layer contains at least a styryl dye and an azo metal chelate compound comprising an azo compound represented by the following general formula (I) and a metal. An optical recording medium comprising: Embedded image (Wherein, R ₁ and R ₂ each independently represent a hydrogen atom, a halogen atom, a nitro group, a cyano group, a hydroxyl group, a carboxyl group,
Amino group, carbamoyl group, substituted or unsubstituted alkyl group, substituted or unsubstituted aryl group, substituted or unsubstituted heterocyclic residue, substituted or unsubstituted alkyloxy group, substituted or unsubstituted aryloxy group, Substituted or unsubstituted alkylthio group, substituted or unsubstituted arylthio group, substituted or unsubstituted alkylamino group, substituted or unsubstituted arylamino group, substituted or unsubstituted alkyloxycarbonyl group, substituted or unsubstituted aryl Represents an oxycarbonyl group, a substituted or unsubstituted alkylcarboxamide group, a substituted or unsubstituted arylcarboxamide, a substituted or unsubstituted alkylcarbamoyl group, a substituted or unsubstituted arylcarbamoyl group, or a substituted or unsubstituted alkenyl group. R _{3 to} R ₆ are the same as R ₁ and R ₂ . Z represents a hydroxyl group, a carboxyl group, an amino group, an alkylcarboxamide group, an arylcarboxamide group, an alkylsulfonamide group, an arylsulfonamide group, a carbamoyl group, an alkylcarbamoyl group, an arylcarbamoyl group, a sulfo group, a sulfino group, or a sulfamoyl group. . ) 2. The optical recording medium according to claim 1, wherein the recording layer contains a styryl dye and an azo metal chelate compound in a weight ratio of 90:10 to 20:80. Optical recording medium. 3. The optical recording medium according to claim 1, wherein the metal atom of the azo metal chelate compound is any one of manganese, cobalt, nickel, and copper. 4. The optical recording medium according to claim 1, wherein the styryl dye is represented by the following general formula (II). Embedded image (In the formula, A represents a ring obtained by condensing a substituted or unsubstituted pyrrole ring, oxazole ring, thiazole ring, selenazole ring, pyridine ring, or imidazole ring with a benzene ring or a naphthalene ring. In the ring, when the nitrogen atom has a +1 valence charge, it contains a -1 valent counter ion or a -1 valent group in the Y portion, wherein Y is the above-mentioned R ₁ , R ₂
Same as. n represents an integer of 1 to 3. ) 5. The optical recording medium according to claim 1, wherein a single layer of the recording layer has a refractive index n of 1.5 ≦ n ≦ 3.
0, an optical recording medium characterized in that the extinction coefficient k satisfies 0.02 ≦ k ≦ 0.2. 6. The optical recording medium according to claim 1, wherein the optical recording medium has a reflective layer.
An optical recording medium, wherein the reflection layer is any one of gold, silver, copper, aluminum and an alloy containing two or more of these metals. 7. The optical recording medium according to claim 1, wherein a track pitch on the substrate is 0.7 to 0.7.
0.8 μm, groove width is half width, 0.18 to 0.40 μm
m, an optical recording medium. 8. The optical recording medium according to claim 1, wherein said optical recording medium has a recording wavelength of 600 to 72.
An optical recording medium used in a region of 0 nm.