JPH11105424A - Optical recording medium and recording method to the medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable application to a high density optical disk system using a semiconductor laser having a specific oscillation wave length or lower by incorporating an azo-metal xylate compound consisting of an azo-based compound and metal indicated by a specific formula in a recording layer. SOLUTION: At least one kind of an azo-metal xylate compound consisting of an azo-based compound and metal indicated by formula is contained in a recording layer. In the formula, Y shows an OH group, a COOH group, a CONH2 group, an NH2 group, an NHR10 group or a SO3 H group, R1 -R6 each indicates independently a hydrogen atom, at least one kind of a group selected form groups consisting of an alkyl group that may have a substituent, an aryl group that may have a substituent, an alkenyl group that may have a substituent, an alkoxy group indicated by OR7 , an amino group indicated by NR8 R9 , a halogen atom, a nitro group, a cyano group, a methyl trifluoride group, and a carboxyl group. The metal shows a group VI-XII element. R7 -R10 respectively show independently groups being the same as in the hydrogen atom or R1 -R6 .

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a large-capacity data write-once optical disc.

[0002]

[Prior art]

(For information recording) Conventional types of write-once recording media (WORM), write-once compact discs (CD-R), write-once compact discs that can only be played back on DVD systems, and large-capacity write-once compact discs (DVD-R) Examples of the technology include the following. 1. (For information recording) Write-once disc (1) Using a cyanine dye as a recording material JP-A-57-82093 JP-A-58-56892 JP-A-58-112790 JP-A-58-114989 JP-A-59-85791 JP-A-60-83236 JP-A-60-98842 JP-A-61-25886 (2) Using a phthalocyanine dye as a recording material JP-A-61-150243 JP-A-61-177287 JP-A-61-154888 JP-A-61-24609 JP-A-62-39286 JP-A-63-37791 JP-A-63-39888

[0003] 2. Write-once compact disc (CD-
R) Prior art (1) Using cyanine dye / metal reflective layer as recording material JP-A-1-159842 JP-A-2-42652 JP-A-2-136656 JP-A-2-168446 (2) Phthalocyanine dye / metal reflective layer US Pat. (3) Using an azo metal chelate dye / metal reflection layer as a recording material JP-A-4-46186 JP-A-4-141489 JP-A-4-360888 JP-A-5-279580

[0004]

[Problems to be solved by the invention]

1. In the current write-once optical disk system, the oscillation wavelength of the laser used is in the range of 770 to 790 nm, and the recording medium is set so that recording and reproduction can be performed at the above wavelength. In the future, as the amount of information increases, it is essential to increase the capacity of recording media. Accordingly, it is easily expected that the wavelength of the laser used for recording and reproduction will be shortened inevitably. However, at present, a recording material which is excellent in light resistance and storage stability and can be recorded and reproduced by an optical pickup using a laser of 700 nm or less has not yet been developed.

[0005] 2. The CD-R has a recording layer of 680 nm to 75 nm.
Since a dye having a maximum absorption wavelength at 0 nm is used and a high reflectance is obtained from 770 nm to 790 nm based on the optical constant and the film thickness configuration, the reflectance is extremely low in a wavelength region of 700 nm or less, and The information recorded and reproduced by the current CD-R system cannot be reproduced by the future system because of the inability to cope with the shortening of the wavelength.

[0006]

Means for Solving the Problems The inventors of the present invention have intensively studied means for solving the above-mentioned problems, and as a result, by using a recording layer containing a dye having a specific structure as a main component, an oscillation wavelength of 700 nm or less. Found that the compound of the present invention can be applied to a high-density optical disk system using a semiconductor laser, and by using the compound of the present invention in combination with an organic dye currently used as a recording material for CD-R,
The present inventors have found that a high reflectance can be obtained even in a wavelength region of 700 nm or less, and have reached the present invention.

That is, the present invention relates to an optical recording medium comprising a recording layer provided directly or via an undercoat layer on a substrate and, if necessary, a reflective layer, a protective layer and the like. The object has been attained by providing an optical recording medium comprising at least one azo metal chelate compound comprising an azo compound represented by the general formula (I) and a metal.

Embedded image [In the formula (I), Y represents an OH group, a COOH group, a CO
Represents an NH ₂ group, NH ₂ group, NHR ₁₀ group or SO ₃ H group, and R ₁ to R ₆ each independently represent a hydrogen atom, an alkyl group which may have a substituent, Or an aryl group which may be substituted, an alkenyl group which may have a substituent, an alkoxy group represented by OR ₇ , an amino group represented by NR ₈ R ₉ , a halogen atom, a nitro group, a cyano group, a methyl trifluoride group and It represents at least one group selected from the group consisting of carboxy groups. Metals belong to 6 groups, 7 groups, 8
Elements of the genera, 9 genera, 10 genera, 11 genera, and 12 genera. R _{7 to} R ₁₀ each independently represent a hydrogen atom or the same group as R _{1 to} R ₆ . ]

Specific examples of metals in the general formula (I) include Group 6 atoms such as Cr, Mo and W; Group 7 atoms such as Mn, Tc and Re; Fe, Co, Ni, Ru, Rh, Pd, O
Group 8 atoms such as s, Ir and Pt; 9 such as Cu, Ag and Au
Group 10 atoms, such as Group 10 atoms, Zn, Cd, and Hg. Specific examples of the alkyl group of R _{1 to} R ₆ 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, an n-octyl group, n-nonyl group, n-decyl group, n-undecyl group, n-dodecyl group, n-tridecyl group, n-tetradecyl group, n-pentadecyl group, n-hexadecyl group, n
A primary alkyl group such as heptadecyl group, n-octadecyl group, n-nonadecyl group, n-icosyl group, isobutyl group, isoamyl group, 2-methylbutyl group, 2-methylpentyl group, 3-methylpentyl group, 4-methyl Pentyl 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, 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-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, neopentyl group, tert-butyl group, tert-hexyl group, tert-amyl group, t
tertiary alkyl groups such as tert-octyl group, cyclohexyl group, 4-methylcyclohexyl group, 4-ethylcyclohexyl group, 4-tert-butylcyclohexyl group,
Examples thereof include cycloalkyl groups such as 4- (2-ethylhexyl) cyclohexyl group, bornyl group, and isobornyl group (adamantane group). Further, these primary and secondary alkyl groups may be substituted with a hydroxyl group or a halogen atom, or may be substituted with the above-mentioned alkyl group via an atom such as oxygen, sulfur, or nitrogen.
Examples of the alkyl group substituted via oxygen include a methoxymethyl group, a methoxyethyl group, an ethoxymethyl group,
An ethoxyethyl group, a butoxyethyl group, an ethoxyethoxyethyl group, a phenoxyethyl group, a methoxypropyl group, an ethoxypropyl group, and the like, as an alkyl group substituted through sulfur, include a methylthioethyl group, an ethylthioethyl group, and an ethyl group. Examples of the alkyl group in which a thiopropyl group, a phenylthioethyl group, or the like is substituted via nitrogen include a dimethylaminoethyl group, a diethylaminoethyl group, a diethylaminopropyl group, and the like.

Examples of the aryl group represented by R _{1 to} R ₆ include a phenyl group, an ethylphenyl group, a butylphenyl group, a nonylphenyl group, a naphthyl group, a butylnaphthyl group and a nonylnaphthyl group. The aryl group may be substituted with a hydroxyl group, halogen, or the like, or may be substituted with the aryl group via an atom such as oxygen, sulfur, or nitrogen. Examples of the aryl group substituted through oxygen include a phenoxyethyl group, a methoxyphenyl group, and a butoxyphenyl group.Examples of the aryl group substituted through sulfur include a phenylthioethyl group, a methylthioethyl group, and a butyl group. Examples of the aryl group in which a thioethyl group or the like is substituted via nitrogen include a dimethylaminophenyl group and a dibutylaminophenyl group. R ₁
The alkenyl group to R _6, ethylene group, propenyl group, butenyl group, hexenyl group, octenyl group, dodecenyl group, cyclohexenyl group, butyl hexenyl group. In addition, the alkenyl group may be substituted with a hydroxyl group, a halogen atom, or the like. R ₇ , R ₈ , R
₉ and R ₁₀ are each independently a hydrogen atom or any of the above R _{1 to} R ₆
Alkyl groups, such as indicated in the embodiment, the aryl group, as described for example in the R ₁ to R _6, an alkenyl group, as described for example in the R ₁ to R ₆ and the like.

Hereinafter, the structure and components of the optical recording medium of the present invention will be described. The structure of the recording medium of the present invention may be a structure of a write-once optical disc shown in FIG. 1 (this structure may be a so-called air sandwich structure in which two sheets of FIG. Good) and the structure of the CD-R medium shown in FIG. 2 or a structure in which two of these are bonded with an adhesive.

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 through 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. A layer may be formed between the recording layer and the substrate via an undercoat layer or a protective layer, or a configuration in which they are laminated for improving the function may be used. Usually, a first substrate / organic dye layer / metal reflective layer / protective layer / adhesive layer / second substrate structure is used.

Recording Layer The recording layer causes some optical change by laser light irradiation and records information by the change. In this recording layer, the general formula (I) of the present invention is included. It is necessary that a dye of the compound shown is contained, and the dye of the present invention may be used alone or in combination of two or more in forming the recording layer. Further, the dye of the present invention may be used by mixing or laminating with other organic dyes, metals and metal compounds for the purpose of improving optical characteristics, recording sensitivity, signal characteristics and the like. Examples of organic dyes include polymethine dyes, naphthalocyanine, phthalocyanine, squarylium, croconium, pyrylium, naphthoquinone, anthraquinone (indanthrene), xanthene, triphenylmethane, azulene, tetrahydro Examples include choline-based, phenanthrene-based, triphenothiazine-based dyes, and metal chelate compounds. The above dyes may be used alone or in combination of two or more. In addition, metals and metal compounds such as In, Te, Bi, Se, Sb, Ge, Sn, A
1, Be, TeO ₂ , SnO, As, Cd and the like can be used in the form of dispersion mixing or lamination.

In the present invention, 680 nm to 750 nm
When a short-wavelength-compatible CD-R medium is formed by mixing the dye having the absorption maximum wavelength and the dye of the present invention, the dye described in the above-mentioned prior art can be used as it is, Such a thing is mentioned.

A cyanine dye represented by the following formula (II)

Embedded image (Wherein, R ₁₁ , R ₁₂ , R ₁₃ , R ₁₄ : an alkyl group having 1 to 3 carbon atoms, R ₁₅ , R ₁₆ : an alkyl group having 1 to 6 carbon atoms which may have a substituent, X : Acid anion or aromatic ring may be condensed with another aromatic ring, or may be substituted with an alkyl, halogen, alkoxy group or acyl group.)

A phthalocyanine dye represented by the following formula (III) or (IV)

Embedded image (Wherein, M ₁ : Ni, Pd, Cu, Zn, Co, Mn,
Fe, TiO, VO, X _{1 to} X ₄ : —OR, —SR, or a hydrogen atom at the α-position, and not all hydrogen atoms. R: a linear or branched alkyl group having 3 to 12 carbon atoms which may have a substituent, a cycloalkyl group which may have a substituent, or a substituent Aryl group. The benzene ring may have a substituent other than the above X _{1 to} X ₄ , and in that case, the substituent of the benzene ring is hydrogen or halogen. )

[0016]

Embedded image (Wherein, M ₂ : Si, Ge, In, Sn. X _{5 to} X ₈ : —OR, —SR, or a hydrogen atom at the α-position, and not all hydrogen atoms. Y ₃ , Y ₄ : —OSiRaRbRc, —OCORa, —O
PORaRb. Ra, Rb, Rc: an alkyl group having 1 to 10 carbon atoms and an aryl group. The benzene ring may have a substituent other than X _{5 to} X ₈ , and in that case, the substituent of the benzene ring is hydrogen or halogen. )

Including the dye of the present invention and the above specific examples 68
The mixing ratio with the dye having an absorption maximum wavelength at 0 nm to 750 nm is 10/100 to 90/100, preferably 40/100 to 20/100, of the present invention / dye having absorption at 680 nm to 750 nm. The thickness of the recording layer is 500 to 5 μm, preferably 1000 to 50 μm.
00 °.

Further, a polymer material such as an ionomer resin, a polyamide resin, a vinyl resin,
Various materials such as natural polymers, silicones and liquid rubbers or silane coupling agents may be dispersed and mixed, or stabilizers (eg, transition metal complexes), dispersants, flame retardants, lubricants for the purpose of improving properties , An antistatic agent, a surfactant, a plasticizer and the like can be used together.

The recording layer is formed by vapor deposition, sputtering, C
It can be carried out by usual means such as VD or solvent application. When the coating method is used, the above-mentioned dye or the like can be dissolved in an organic solvent, and the coating can be performed by a conventional coating method such as spraying, roller coating, dipping, and spin coating. As the organic solvent to be used, generally, alcohols such as methanol, ethanol and isopropanol, ketones such as acetone, methyl ethyl ketone and cyclohexanone, and N, N-
Amides such as dimethylformamide and N, N-dimethylacetamide; sulfoxides such as dimethylsulfoxide; ethers such as tetrahydrofuran, dioxane, diethyl ether and ethylene glycol monomethyl ether; esters such as methyl acetate and ethyl acetate; chloroform; Aliphatic halogenated hydrocarbons such as methylene, dichloroethane, carbon tetrachloride, trichloroethane, benzene, xylene, monochlorobenzene,
Examples include aromatics such as dichlorobenzene, cellosolves such as methoxyethanol and ethoxyethanol, and hydrocarbons such as hexane, pentane, cyclohexane, and methylcyclohexane.

Substrate A necessary characteristic of the substrate is that the substrate must be transparent to the laser used only when recording and reproduction are performed from the substrate side, and the substrate does not need to be transparent when recording and reproduction are performed from the recording layer side. As a substrate material, for example, plastic such as polyester, acrylic resin, polyamide, polycarbonate resin, polyolefin resin, phenol resin, epoxy resin, polyimide, glass, ceramic, or metal can be used. When only one substrate is used, or when two substrates are used in a sandwich form, a guide groove for tracking, a guide pit, and a preformat such as an address signal are formed on the surface of the first substrate. Need to be.

Intermediate Layer A layer provided other than the substrate, the recording layer, the reflective layer, and the protective layer including the undercoat layer and the like is referred to as an intermediate layer here. This intermediate layer
For the purpose of improving adhesiveness, barrier against water or gas, improving storage stability of recording layer, improving reflectivity, protecting substrate and recording layer from solvent, forming guide grooves, guide pits, preformat, etc. used. For the purpose of the present invention, polymer materials, for example, 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. For the purpose, and other than the above-mentioned polymer materials, inorganic compounds such as SiO, MgF, SiO ₂ , TiO ₂ , ZnO, Ti
N, SiN and the like, and further, a metal or a metalloid, for example,
Zn, Cu, Ni, Cr, Ge, Se, Au, Ag, A
1, etc. can be used. Metals such as Al, Au, Ag and the like, and organic thin films having metallic luster such as methine dyes and xanthene dyes can be used for the purpose. Cured resin, thermosetting resin, 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 is suitable.

Metal Reflection Layer The metal reflection layer is made of a metal or semi-metal which is hardly corroded and has a high reflectance by itself. Examples of the material include Au and A.
g, Cr, Ni, Al, Fe, Sn, and the like. Au, Ag, and Al are most preferable in terms of reflectance and productivity. These metals and metalloids may be used alone. It may be a kind of alloy. Evaporation,
Sputtering, etc., and the film thickness is 50 to 5
000 °, preferably 100-3000 °.

Protective Layer, Hard Coat Layer on Substrate Surface The protective layer and hard coat layer on the substrate surface protect the recording layer (reflection / absorption layer) from scratches, dust, dirt, etc., and the storage stability of the recording layer (reflection / absorption layer). It is used for the purpose of improving the reflectance and the reflectance. For these purposes, the materials shown in the undercoat layer can be used. In addition, as the inorganic material, SiO, SiO ₂ or the like can be used,
As organic materials, polymethyl acrylate, polycarbonate, epoxy resin, polystyrene, polyester resin, vinyl resin, cellulose, aliphatic hydrocarbon resin, natural rubber, styrene butadiene resin, chloroprene rubber,
A heat-softening and heat-melting resin such as wax, alkyd resin, drying oil and rosin can also be used. The most preferable example of the protective layer or the substrate surface hard coat layer among 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 to 30 μm.
m, preferably 0.05 to 10 μm. In the present invention, the intermediate layer, the protective layer, and the substrate-side hard coat layer include a stabilizer, a dispersant, a flame retardant, a lubricant, an antistatic agent, a surfactant, a plasticizer, and the like as in the case of the recording layer. It can be contained.

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

Adhesive Any material can be used as long as it can bond two recording media, and from the viewpoint of productivity, an ultraviolet-curable or hot-melt adhesive is preferable.

[0026]

Embodiments of the present invention will be described below. However, the present invention is not limited to these examples. Compound No. shown below. Are shown in Tables 5 to 8 below.

Example 1 Compound No. 1 was formed on a 1.2 mm thick PMMA substrate on which a guide groove having a depth of 1200 mm, a half width of 0.4 μm, and a track pitch of 1.4 μm was formed by photopolymer.
1 was applied with a spinner and the thickness was 800
The recording layer of Å was formed to obtain a recording medium.

Embodiments 2 to 5 No. 1 was used instead of Compound 1. 2, 3,
A recording medium was formed in exactly the same manner as in Example 1 using 4 and 5 compounds.

Comparative Example 1 A recording medium was formed in exactly the same manner as in Example 1 except that the following compound (A) was used instead of one compound.

Embedded image

The recording media of Examples 1 to 5 and Comparative Example 1 were subjected to evaluation tests under the following conditions, and the results are shown in Table 1 below. <Recording conditions> Laser oscillation wavelength: 635 nm Recording frequency: 1.25 MHz Recording linear velocity: 1.2 m / sec <Reproduction conditions> Laser oscillation wavelength: 650 nm Reproduction power: Continuous light of 0.25 to 0.3 mW Scanning band width: 30KHz <Light fastness test condition> Light fastness test: 40,000 Lux, Xe light, continuous irradiation for 50 hours Storage test: 85 ° C 85% left for 720 hours

[0031]

[Table 1]

Example 6 Compound Example No. 1 was prepared on a 1.2 mm thick injection molded polycarbonate substrate having a guide groove with a depth of 1000 mm, a half width of 0.4 μm and a track pitch of 1.6 μm. 6 was dissolved in a mixed solution of methylcyclohexane, 2-methoxyethanol, methyl ethyl ketone, and tetrahydrofuran, and spin-coated to form an organic dye layer having a thickness of 1800 、, and then a reflection layer of 2000Å was provided by sputtering. A 5 μm protective layer of an acrylic photopolymer was provided thereon to obtain a recording medium.

Embodiments 7 to 10 No. 6 compounds, respectively.
Using 7, 8, 9, 10 and the compound, a recording medium was obtained in exactly the same manner as in Example 6.

Comparative Example 2 In Example 6, the organic thin film was A recording medium was prepared using the compound (A) of Comparative Example 1 instead of the six compounds.

Recording Conditions Using a semiconductor laser beam having an oscillation wavelength of 635 nm and a beam diameter of 1.0 μm, an EFM signal was recorded on the recording media of Examples 6 to 10 and Comparative Example 2 while tracking (linear velocity of 1.4 m / m). sec), reproduction was performed with continuous light of the same laser, the reproduced waveform was observed, and the results are shown in Table 2 below.

[0036]

[Table 2]

Example 11 A compound (B) and the following compound (B) were prepared on a 1.2 mm-thick injection-molded polycarbonate substrate having a guide groove having a depth of 1,000 mm, a half width of 0.45 μm, and a track pitch of 1.6 μm.
Eleven compounds were mixed at a weight ratio of 1: 1. This was dissolved in a mixed solvent of methylcyclohexane, 2-methoxyethanol, 2-ethoxyethanol, methylethylketone, and tetrahydrofuran, and spinner-coated to give a thickness of 1700 °
Is formed, and then gold 2 is formed by sputtering.
A reflective layer of 000 ° was formed, and a 5 μm protective layer of an acrylic photopolymer was further provided thereon to obtain a recording medium.

Embedded image

Embodiments 12 to 14 In the embodiment 11, the recording layers were No. In place of No. 11 compounds, respectively. Example 1 using compounds 12, 13, and 14
A recording medium was obtained in exactly the same manner as in Example 1.

Embodiments 15 to 17 In the embodiment 11, the recording layers were No. 1 to No. 4. In place of No. 11 compounds, respectively. A recording medium was obtained in exactly the same manner as in Example 11, except that Compounds 15, 16, and 17 were used and the following compound (C) was used instead of Compound (B).

Examples 18 to 20 In Example 11, the recording layer was prepared using Compound No. In place of No. 11 compounds, respectively. Using 18, 19 and 20 compounds,
A recording medium was obtained in exactly the same manner as in Example 11, except that the following compound (C) was used instead of the compound (B).

Comparative Examples 3 and 4 In Example 11, the organic recording layer was prepared by using only the compound (B) of Comparative Example 1 and only the compound (C) shown below.
A recording medium was obtained in the same manner as described above.

Embedded image

Reproduction Conditions Using a semiconductor laser having an oscillation wavelength of 780 nm and a beam diameter of 1.6 μm for the recording media of Examples 11 to 20 and Comparative Examples 3 and 4, recording an EFM signal while tracking (a linear velocity of 1.4 m / m). sec) and the laser and oscillation wavelength 6
Reproduction was performed with continuous light of a semiconductor laser having a beam diameter of 50 nm and a beam diameter of 1.4 μm, and the reproduction waveform was observed. The results are shown in Tables 3 and 4 below.

[0043]

[Table 3]

[0044]

[Table 4]

The following Tables 5, 6, 7, and 8 show the compounds No. used in the above Examples and Comparative Examples. 1 to 20 are shown.

[Table 5]

[0046]

[Table 6]

[0047]

[Table 7]

[0048]

[Table 8] Note * In R _{3 to} R ₆ , all are hydrogen atoms unless otherwise specified. * Ph represents a phenyl group.

[0049]

【effect】

1. Claim 1 An information recording medium which can be recorded and reproduced with a laser beam in a wavelength range of 700 nm or less and has excellent light resistance and storage stability can be provided. 2. Claim 2 It is possible to provide an optical recording medium that can be used as a CD-R in the current system and can reproduce recorded information even in a next-generation large-capacity optical disk system. 3. According to a third aspect of the present invention, there is provided a recording medium capable of recording high-quality signal characteristics. 4. [Claim 4] It is possible to provide a recording method exhibiting each of the above effects.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of a configuration of a normal write-once optical recording medium. FIG. 2A is a view showing a type having a recording layer 2 and a second substrate 10 on a first substrate 1. FIG. 2B is a view showing a type having an undercoat layer 3 and a recording layer 2 on a first substrate 1. (C) is a diagram showing a type having a protective layer 4 on the recording layer 2 of (b). (D) A hard coat layer 5 is formed on the back surface of the first substrate 1 of (c).
FIG.

FIG. 2 is a schematic sectional view of a configuration of an optical recording medium for CD-R. FIG. 2A is a diagram showing a type having a recording layer 2, a metal reflective layer 6, and a protective layer 4 on a first substrate 1. FIG. 3B is a view showing a type having the undercoat layer 3 on the first substrate 1 of FIG. (C) is a view showing a type in which the undercoat layer 3 of (b) is composed of two layers.

FIG. 3 is a schematic sectional view of a medium configuration for a DVD-R. FIG. 2A is a diagram showing a type having a recording layer 2, a metal reflective layer 6, an adhesive layer 7, and a second substrate 10 on a first substrate 1, and a hard coat layer 5 on the back surface of the substrate 1. (B) is a view showing a type having the protective layer 4 between the metal reflective layer 6 and the adhesive layer 7 of (a). (C) The first substrate 1 includes the recording layer 2, the metal reflection layer 6, the protection layer 4, the spacer 8, the protection layer 4, the metal reflection layer 6, the recording layer 2, and the second substrate 10 on the first substrate 1. FIG. 6 is a view showing a type having an undercoat layer 3 on the back surface of the present invention. (D) The recording layer 2, the translucent layer 9, the spacer 8, the recording layer 2, the metal reflection layer 6 and the second substrate 10 are provided on the first substrate 1, and the undercoat layer 3 is provided on the back surface of the first substrate 1. It is a figure which shows the thing of the type which has.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 1st board | substrate 2 recording layer 3 board | substrate undercoating layer 4 protective layer 5 hard coat layer 6 metal reflection layer 7 adhesive layer 8 spacer 9 translucent film 10 2nd board | substrate

Continued on the front page (72) Inventor Noboru Sasa 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Company (72) Inventor Yasuhiro Higashi 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Company

Claims (4)

[Claims] 1. An optical recording medium comprising at least a recording layer provided directly or via an undercoat layer on a substrate, wherein the recording layer is made of an azo compound represented by the following general formula (I) and a metal: An optical recording medium comprising at least one chelate compound. Embedded image [In the formula (I), Y represents an OH group, a COOH group, a CO
Represents an NH ₂ group, NH ₂ group, NHR ₁₀ group or SO ₃ H group, and R ₁ to R ₆ each independently represent a hydrogen atom, an alkyl group which may have a substituent, Or an aryl group which may be substituted, an alkenyl group which may have a substituent, an alkoxy group represented by OR ₇ , an amino group represented by NR ₈ R ₉ , a halogen atom, a nitro group, a cyano group, a methyl trifluoride group and It represents at least one group selected from the group consisting of carboxy groups. Metals belong to 6 groups, 7 groups, 8
Elements of the genera, 9 genera, 10 genera, 11 genera, and 12 genera. R _{7 to} R ₁₀ each independently represent a hydrogen atom or the same group as R _{1 to} R ₆ . ] 2. An optical recording medium wherein the recording layer comprises a mixed layer of a dye having a maximum absorption wavelength at 680 to 750 nm in addition to an azo metal chelate compound. 3. The optical recording medium according to claim 2, wherein the dye having a maximum absorption wavelength at 680 to 750 nm is at least one selected from the group consisting of a cyanine dye, a phthalocyanine dye, and an azo metal chelate compound. 4. A recording method for recording on the optical recording medium according to claim 1, at a recording wavelength of 600 to 720 nm.