JP2002283731A - Optical recording medium and method for optical recording - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical recording medium and a method for optical recording using a recording medium excellent in light resistance and stability of preservation and applicable to DVD-R disc system using a semi-conductive laser having an oscillating wave length in a short wave length range. SOLUTION: An optical recording medium and a method for optical recording is characterized by containing a least one of azo compounds represented by general formula (1) and azo metal chelate pigment compounds consisting of metal, metal oxide or salt of them, as to the optical recording medium provided with the recording layer on a substrate.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical recording medium having a dye recording layer capable of recording and reproducing with a short wavelength laser beam, and an optical recording method.

[0002]

2. Description of the Related Art At present, as a next-generation large-capacity optical disk, D
VD-R is under development. To improve the recording capacity, the development of recording materials for miniaturization of recording pits, MPE
It is necessary to adopt an image compression technique represented by G2, and to develop a technique for shortening the wavelength of a semiconductor laser for reading recording pits. Until now, semiconductor lasers in the red wavelength range have 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 a 650 nm band laser diode. Under these circumstances, the most preferable DVD-R medium is a medium that can record and reproduce at a wavelength of 630 to 670 nm. However, lightfastness,
A recording material which has excellent storage stability and can be recorded and reproduced by an optical pickup using a laser of 670 nm or less has not yet been developed. In addition, as the density of the optical disk increases, the track pitch of the guide groove formed on the substrate decreases. For the production of optical disks, a method of applying a solvent solution for the recording layer material such as a spin coating method is used, but it is difficult to control the shape of the coating film due to the narrow track pitch. Generally, a method of controlling the shape of a coating film is performed by mixing an additive into a coating solvent or the like, and a method of changing the solubility of a recording material. However, the former has a problem in quality control of the coating solvent, and the latter has a problem in that the optical characteristics of the recording material greatly change.

[0003]

SUMMARY OF THE INVENTION The present invention is directed to a recording system which is superior in light resistance and storage stability to a DVD-R disk system using a semiconductor laser having an oscillation wavelength in a short wavelength, compared to the prior art. It is an object of the present invention to provide an optical recording medium and an optical recording method using a material.

[0004]

As a result of investigations by the present inventors, if a recording layer containing a dye having a specific structure as a main component is used, a next-generation large-capacity optical disk system using a semiconductor laser having an oscillation wavelength of 670 nm or less is used. The present invention was found to be applicable to the present invention. That is, the above problems are as follows:
To 7) (hereinafter referred to as Inventions 1 to 7). 1) In an optical recording medium having a recording layer provided on a substrate, at least one azo compound represented by the general formula (I) and an azo metal chelate dye compound comprising a metal, a metal oxide or a salt thereof are contained in the recording layer. An optical recording medium characterized by containing various types.

Embedded image In the general formula (I), the ring A together with the carbon atom and the nitrogen atom to which it is attached, is derived from pyrrole, imidazole, pyrazole, triazole, tetrazole, indole, isoindole, benzimidazole, indazole, purine, perimidine Represents a residue forming a heterocyclic ring selected from the group consisting of: M represents a metal or a metal oxide; R ₁ and R ₂ each independently represent a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group; And R ₃
To R ₆ each independently represent a hydrogen atom, a halogen atom, a nitro group, a cyano group, a hydroxyl group, a carboxyl group, an amino group,
Substituted or unsubstituted alkyl group, substituted or unsubstituted aryl group, substituted or unsubstituted heterocyclic residue, substituted or unsubstituted alkylcarbonyl group, substituted or unsubstituted arylcarbonyl group, substituted or unsubstituted alkyl Oxycarbonyl group, substituted or unsubstituted aryloxycarbonyl group, substituted or unsubstituted alkylsulfonyl group, substituted or unsubstituted arylsulfonyl group, substituted or unsubstituted alkylthiooxy group, substituted or unsubstituted arylthiooxy group ,
Substituted or unsubstituted alkyloxy group, substituted or unsubstituted aryloxy group, substituted or unsubstituted alkylamino group, substituted or unsubstituted arylamino group, substituted or unsubstituted alkylcarbonylamino group, substituted or unsubstituted Represents a substituted or unsubstituted alkylcarbamoyl group, a substituted or unsubstituted arylcarbamoyl group, or a substituted or unsubstituted alkenyl group, and n represents 2 or 3. R ₂ and R ₃ , R ₃ and R ₄ , R ₄ and R
₅ may be linked to form a ring. Note that R ₁ and R ₂ do not represent a hydrogen atom. 2) The optical recording medium according to 1), wherein the valence of the metal is divalent or trivalent. 3) The optical recording medium according to 1) or 2), wherein the metal is any one of manganese, cobalt, nickel, and copper. 4) In the thermogravimetric analysis of the azo metal chelate dye compound (organic dye) constituting the recording layer, the ratio of weight loss to temperature in the main weight loss process is 2% / ° C. or more, 1) to 3). The optical recording medium according to any one of the above). 5) In the thermogravimetric analysis of the azo metal chelate dye compound (organic dye) constituting the recording layer, the total weight loss in the main weight loss process is 30% or more, and the weight loss start temperature is 200 to 350 ° C.
The optical recording medium according to any one of 1) to 4), wherein 6) The method according to any one of 1) to 5), wherein 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 0.36 μm. Optical recording medium. 7) The single layer of the recording layer has a refractive index n of 1.5 ≦ n ≦ 3.0 and a extinction coefficient k of 0.02 ≦ k ≦ 0.2 with respect to light in a wavelength range of ± 5 nm. An optical recording / reproducing method using the optical recording medium according to any one of 1) to 6).

Hereinafter, the present invention will be described in detail.
In the general formula (I), the ring A together with the carbon atom and the nitrogen atom to which it is attached, is derived from pyrrole, imidazole, pyrazole, triazole, tetrazole, indole, isoindole, benzimidazole, indazole, purine, perimidine Represents a residue forming a heterocyclic ring selected from the group consisting of: and M represents a metal or a metal oxide. Further, R _{1 to} R ₆ are as described in the above 1). Specific examples of the halogen atom in the above description include fluorine, chlorine, bromine, and iodine. Specific examples of the alkyl group include a methyl group, an ethyl group, and n-
Propyl group, n-butyl group, n-pentyl group, n-hexyl group, n-heptyl group, n-octyl group, n-nonyl group, primary alkyl group such as n-decyl group, isobutyl group,
Isoamyl group, 2-methylbutyl group, 2-methylpentyl group, 3-methylpentyl group, 4-methylpentyl group,
2-ethylbutyl, 2-methylhexyl, 3-methylhexyl, 4-methylhexyl, 5-methylhexyl, 2-ethylpentyl, 3-ethylpentyl, 2-methylheptyl, 3-methyl Heptyl 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-ethylhexyl group, 1
-Propylpentyl group, 1-isopropylpentyl group,
1-isopropyl-2-methylbutyl group, 1-isopropyl-3-methylbutyl group, 1-methyloctyl group, 1
-Propylhexyl group, secondary alkyl group such as 1-isobutyl-3-methylbutyl group, neopentyl group, tert
A tertiary alkyl group such as -butyl group, tert-hexyl group, tert-amyl group, tert-octyl group, cyclohexyl group, 4-methylcyclohexyl group, 4-ethylcyclohexyl group, 4-tert-butylcyclohexyl group, 4- (2-ethylhexyl) cyclohexyl group,
And cycloalkyl groups such as a bornyl group and an isobornyl group (adamantane group).

Further, these primary and secondary alkyl groups are
A hydroxyl group, a halogen atom, a nitro group, a carboxy group, a cyano group, a substituted or unsubstituted aryl group, a substituted or unsubstituted heterocyclic residue, and the like;
The alkyl group may be substituted via an atom such as 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,
Methoxypropyl group, ethoxypropyl group, piperidino group, morpholino group, etc., as the alkyl group substituted via sulfur, methylthioethyl group, ethylthioethyl group, ethylthiopropyl group, phenylthioethyl group, etc. Examples of the alkyl group substituted via nitrogen include a dimethylaminoethyl group, a diethylaminoethyl group, and a diethylaminopropyl group. Specific examples of the aryl group include a phenyl group, a pentalenyl group, an indenyl group, a naphthyl group, an azulenyl group, a heptalenyl group, a biphenylenyl group, a phenalenyl group, a phenanthrenyl group, an anthracenyl group, a triphenylenyl group, and a pyrenyl group. Specific examples of the heterocyclic residue include an indolyl group, a furyl group, a thienyl group, a pyridyl group, a piperidyl group, a quinolyl group, an isoquinolyl group, a piperidino group, a morpholino group, and a pyrrolyl group.

[0007] Specific examples of the alkylcarbonyl group are those in which a substituted or unsubstituted alkyl group is directly bonded to a carbon atom of the carbonyl group. Specific examples of the alkyl group include those described above. be able to.
Specific examples of the arylcarbonyl group may be those in which a substituted or unsubstituted aryl group is directly bonded to a carbon atom of the carbonyl group, and specific examples of the aryl group include those described above. . Specific examples of the alkyloxycarbonyl group include those in which a substituted or unsubstituted alkyl group is directly bonded to an oxygen atom of the oxycarbonyl group, and specific examples of the alkyl group include those described above. Can be. Specific examples of the aryloxycarbonyl group may be those in which a substituted or unsubstituted aryl group is directly bonded to the oxygen atom of the oxycarbonyl group, and specific examples of the aryl group include those described above. Can be. Specific examples of the alkylsulfonyl group include those in which a substituted or unsubstituted alkyl group is directly bonded to a sulfur atom of the sulfonyl group, and specific examples of the alkyl group include those described above. . Specific examples of the arylsulfonyl group may be those in which a substituted or unsubstituted aryl group is directly bonded to a sulfur atom of the sulfonyl group, and specific examples of the aryl group include those described above. .

[0008] Specific examples of the alkylthioxy group are 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. . Specific examples of the arylthioxy group may be any one in which a substituted or unsubstituted aryl group is directly bonded to a sulfur atom,
Specific examples of the aryl group include those described above. Specific examples of the alkyloxy group may be those in which a substituted or unsubstituted alkyl group is directly bonded to an oxygen atom, and specific examples of the alkyl group include those described above. Specific examples of the aryloxy group may be those in which a substituted or unsubstituted aryl group is directly bonded to an oxygen atom, and specific examples of the aryl group include those described above. Specific examples of the alkylamino group may be those in which a substituted or unsubstituted alkyl group is directly bonded to a nitrogen atom, and specific examples of the alkyl group include those described above. Specific examples of the arylamino group may be those in which a substituted or unsubstituted aryl group is directly bonded to a nitrogen atom, and specific examples of the aryl group include those described above.

Specific examples of the alkylcarbonylamino group include those in which a substituted or unsubstituted alkyl group is directly bonded to a carbon atom of the carbonylamino group. Specific examples of the alkyl group are those described above. Can be mentioned. Specific examples of the arylcarbonylamino group include those in which a substituted or unsubstituted aryl group is directly bonded to a carbon atom of the carbonylamino group. Specific examples of the aryl group include those described above. Can be. Specific examples of the alkylcarbamoyl group include those in which a hydrogen atom, a substituted or unsubstituted alkyl group is directly and independently bonded to the nitrogen atom of the carbamoyl group, and specific examples of the alkyl group are as described above. Can be mentioned. Specific examples of the arylcarbamoyl group include those in which a hydrogen atom or a substituted or unsubstituted aryl group is directly and independently bonded to the nitrogen atom of the carbamoyl group, and specific examples of the aryl group are as described above. Can be mentioned.

When M in the general formula (I) is a divalent or trivalent metal atom, specific examples include titanium, vanadium, chromium, manganese, iron, cobalt, nickel,
Copper, zirconium, niobium, molybdenum, technetium, ruthenium, rhodium, palladium and the like,
Specific examples of the metal oxide include vanadium oxide. In particular, azo metal chelate dye compounds of manganese, cobalt, nickel, and copper have excellent optical properties as optical recording materials.

A feature of the present invention is that an azo compound composed of a heterocyclic residue having an active hydrogen and a coupler having no active hydrogen acts on a metal to form a stable azo compound which can be used as a recording material for an optical recording medium. An azo metal chelate dye compound has been found. BACKGROUND ART A heterocyclic azo metal chelate dye compound used in a conventionally known optical recording medium is composed of a coupler having active hydrogen and a heterocyclic residue having no active hydrogen group. M represents a metal atom.・ Conventional type

Embedded image ・ Azo metal chelate dye compound of the present invention

Embedded image

Next, as items necessary for forming the recording layer, there are optical characteristics and thermal characteristics. As the optical characteristics, it is necessary that the recording / reproducing wavelength has a large absorption band on the short wavelength side with respect to a laser beam having a wavelength of 630 nm to 690 nm, and the recording / reproducing wavelength is near the long wavelength end of the absorption band. . This corresponds to the recording / reproducing wavelength of 630 nm to 69.
It means having a large refractive index and extinction coefficient at 0 nm. Specifically, the refractive index n of the recording layer single layer with respect to light in the wavelength region near the long wavelength near the recording / reproducing wavelength is 1.5 ≦ n ≦
3.0, and the extinction coefficient k is preferably in the range of 0.02 ≦ k ≦ 0.2. If n is less than 1.5, it is difficult to obtain a sufficient optical change, so that the recording modulation degree is low, which is not preferable. If n is more than 3.0, the wavelength dependency becomes too high. Even in the recording / reproducing wavelength region, an error occurs, which is not preferable. Also,
If k is less than 0.02, the recording sensitivity deteriorates, which is not preferable. If k exceeds 0.2, it is difficult to obtain a reflectance of 50% or more, which is not preferable.

As for the thermal characteristics, it is necessary that the weight loss in the main weight loss process in thermogravimetric analysis is sharp with respect to the temperature. This is because the organic material film is decomposed in the main weight reduction process, causing a decrease in film thickness and a change in optical constant, thereby forming a recording portion in an optical sense. Therefore, when the weight loss in the main weight loss process is gentle with respect to the temperature, the recording portion is formed over a wide temperature range, which is extremely disadvantageous when a high-density recording portion is formed. For the same reason, the use of a material having a plurality of weight loss processes is also disadvantageous for high density. In the present invention, among several weight loss processes, the one with the largest weight loss rate is referred to as the main weight loss process.

In the present invention, the slope of the weight loss is determined as follows. As shown in FIG. 1, an organic dye having a mass M0 was added at 10 ° C./min. To raise the temperature. As the temperature rises, the mass decreases by a small amount, and becomes substantially linear ab
The graph shows a weight loss curve, and when a certain temperature is reached, a sharp weight loss occurs, and a weight loss occurs substantially along a straight line cd. If the temperature is further increased, the abrupt weight loss ends and the weight decreases substantially along the straight line ef. Now, let the temperature at the intersection of the straight line ab and the straight line cd be T1
(° C.), the residual weight with respect to the initial mass M0 is m1 (%),
The temperature at the intersection of the straight line cd and the straight line ef is T2
(° C.), assuming that the residual weight with respect to the initial mass M0 is m2 (%), the temperature at which the main weight loss process starts is T1, the temperature at which the main weight loss process ends is T2, and the weight loss rate in the main weight loss process with respect to the initial weight is (m1 -M2) (%), and the ratio of weight loss to temperature in the main weight loss process is a value represented by the following equation.

## EQU1 ## (m1-m2) (%) / (T2-T1) (.degree. C.)

According to the above definition, as a recording material used for an optical recording medium, the ratio of weight loss to temperature in the main weight loss process is preferably 2% / ° C. or more, preferably 2%.
When a recording material having a temperature of less than / ° C. is used, the spread of the recording portion becomes large, and it becomes difficult to form a short recording portion, which is not suitable for an optical recording medium. Further, the weight loss rate in the main weight loss process is preferably 30% or more, and if it is less than 30%, there is a possibility that good recording modulation and recording sensitivity may not be obtained. Further, as the thermal characteristics, the weight loss starting temperature needs to be 350 ° C. or less,
It is desirable to be in the range of 50 ° C. Weight loss start temperature is 3
When the temperature exceeds 50 ° C., the power of the recording laser beam becomes too high, which is not practical.

The substrate has a track pitch of 0.7 to 0.8 μm on the substrate and a groove width of 0.18 to
It must be 0.36 μm. The substrate is typically 10 depth
It has a guide groove of 00 to 2500 °, and the track pitch is usually 0.7 to 1.0 μm, but preferably 0.7 to 0.8 μm for high capacity applications. If the groove width is less than 0.18 μm, it may be difficult to obtain a sufficient tracking error signal intensity, and the groove width may be 0.36 μm.
Exceeding the range is not preferable because the recording portion tends to spread laterally when recording is performed.

The layer structure of the optical recording medium of the present invention may be a structure of FIG. 2 which is a usual write-once optical disk (a so-called air sandwich type in which two media of FIG. 2 are bonded, or a close bonding structure). 3) and a structure for a CD-R as shown in FIG. 3 and a structure for a DVD-R as shown in FIG. As a preferable layer structure, a structure in which the first substrate and the second substrate are bonded with an adhesive via a recording layer is a basic structure. The recording layer may be a single layer of an organic dye layer, or may have a laminated structure of an organic dye layer and a metal reflection layer in order to increase the reflectance. An undercoat layer or a protective layer may be provided between the recording layer and the substrate, and may be laminated to improve the function. The structure most commonly used is a structure comprising a first substrate / organic dye recording layer / metal reflective layer / protective layer / adhesive layer / second substrate.

Hereinafter, the required characteristics of each layer and examples of constituent materials will be described in order. <Substrate> As a necessary characteristic of the substrate, the substrate is transparent to the laser beam used only when recording and reproduction are performed from the substrate side, and need not be transparent when recording and reproduction are performed from the recording layer side.
Substrate materials include plastics such as polyester, acrylic resin, polyamide, polycarbonate, polyolefin, phenolic resin, epoxy resin, polyimide, etc.
Glass, ceramic, metal, or the like can be used. When only one substrate is used, or when two substrates are used in a sandwich form, a guide groove or a guide pit for tracking is formed on the surface of the first substrate, and a preformat such as an address signal is formed. Good.

<Intermediate Layer> The layers provided other than the substrate, the recording layer, the reflective layer, and the protective layer, including the undercoat layer and the like, are herein referred to as intermediate layers. This intermediate layer comprises (a) improved adhesiveness, (b) a barrier against water or gas, (c) improved storage stability of the recording layer, (d) improved reflectance, and (e) substrate from solvent. And protection of recording layer, (f) guide groove, guide pit,
It is used for the purpose of forming a preformat or the like. For the purpose of (a), various polymer substances such as ionomer resins, polyamides, vinyl resins, natural resins, natural polymers, silicones, liquid rubbers, and silane coupling agents can be used. For the purposes of (b) and (c), in addition to the polymer material, SiO ₂ , M
inorganic compounds such as gF ₂ , SiO, TiO ₂ , ZnO, TiN, SiN, Zn, Cu, Ni, Cr, Ge, Se,
Metals or metalloids such as Au, Ag, and Al can be used. In addition, for the purpose of (d), an organic thin film having a metallic luster such as a metal such as Al or Ag or a methine dye or a xanthene dye can be used, and for the purposes of (e) and (f), For example, an ultraviolet curing resin, a thermosetting resin, a thermoplastic resin, or the like can be used. The thickness of the undercoat layer is
The thickness is 0.01 to 30 μm, preferably 0.05 to 10 μm.

<Recording Layer> The recording layer causes some optical change upon irradiation with a laser beam and can record information by the change. The recording layer contains the dye compound of the present invention. It is necessary to use the dye of the present invention alone or in combination of two or more in forming the recording layer. Further, the dye compound of the present invention has optical properties,
For the purpose of improving recording sensitivity, signal characteristics, and the like, it may be mixed with other organic dyes, metals, metal compounds, or the like, or may be laminated. Examples of other organic dyes include polymethine dyes, naphthalocyanine-based, phthalocyanine-based, squarylium-based, croconium-based, pyrylium-based, naphthoquinone-based, anthrequinone (indanthrene) -based, xanthene-based, triphenylmethane-based, and azulene-based , Tetrahydrocholine-based, phenanthrene-based, triphenothiazine-based dyes, metal chelate compounds, and the like. These dyes may be used alone or in combination of two or more. In addition, In, Te, Bi, Se, Sb, G
e, Sn, Al, Be, As, Cd, TeO ₂ , Sn
It is also possible to disperse and mix a metal or metal compound such as O, or to laminate and use these materials. Further, various polymer materials such as an ionomer resin, a polyamide resin, a vinyl resin, a natural polymer, a silicone, a liquid rubber, or a silane coupling agent may be dispersed and mixed in the dye. Alternatively, it may be used together with a stabilizer (eg, 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 (chemical vapor deposition) or solution coating. When the coating method is used, the dye or the like may be dissolved in an organic solvent or the like and applied by a conventional coating method such as spraying, roller coating, dipping, or spin coating. Examples of the organic solvent 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; sulfoxides such as dimethyl sulfoxide; Ethers such as tetrahydrofuran, dioxane, diethyl ether and ethylene glycol monomethyl ether; esters such as methyl acetate and ethyl acetate; aliphatic halogenated hydrocarbons such as chloroform, methylene chloride, dichloroethane, carbon tetrachloride and trichloroethane; or Aromatics such as benzene, xylene, monochlorobenzene and dichlorobenzene; cellosolves such as methoxyethanol and ethoxyethanol; hexane, pentane, cyclohexane,
Hydrocarbons such as methylcyclohexane can be used. The recording layer has a thickness of 100 to 10 μm, preferably 200 to 2000 °.

<Metal Reflective Layer> Examples of the material of the reflective layer include metals and semi-metals which can be easily obtained and have high reflectivity and are hardly corroded. Specific examples thereof include Au, Ag, Cr, Ni, and A.
Examples thereof include l, Fe, and Sn, but Au, Ag, and Al are most preferable in terms of reflectivity and productivity. Further, these metals and metalloids may be used alone or as two kinds of alloys. Examples of the method for forming the reflective layer include vapor deposition, sputtering, and the like.
0 to 3000 °.

<Protective Layer, Hard Coat Layer on Substrate Surface> The protective layer or the hard coat layer on the substrate surface comprises (a) protection of the recording layer (reflection / absorption layer) from scratches, dust, dirt, etc .; It is used for the purpose of improving the storage stability of the reflection / absorption layer), (c) improving the reflectance, and the like. As the material, those shown in the intermediate layer can be used. In addition, SiO, SiO ₂ or the like can be used as an inorganic material, and polymethyl acrylate, polycarbonate, epoxy resin, polystyrene, polyester, vinyl resin, cellulose, aliphatic hydrocarbon resin, aromatic hydrocarbon resin, natural material can be used as organic material. Thermosoftening and heat melting resins such as rubber, styrene butadiene resin, chloroprene rubber, wax, alkyd resin, drying oil and rosin can also be used.
Among the above materials, the most preferable for 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 substrate surface hard coat layer is 0.01 to
It is 30 μm, preferably 0.05 to 10 μm. In the present invention, the intermediate layer, the protective layer and the substrate-side hard coat layer contain 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.

Preferred examples of the azo metal chelate dye compound represented by the general formula (I) are shown in Tables 1 to 3 below.

[Table 1]

[Table 2]

[Table 3]

[0025]

The present invention will be described below in more detail with reference to examples and comparative examples, but the present invention is not limited to these examples.

Example 1 On a 0.6 mm thick injection molded polycarbonate substrate,
Using photopolymer, depth 1750Å, half width 0.2
After forming a guide groove having a track pitch of 5 μm and a track pitch of 0.74 μm, Compound No. 1,1,2,2-tetrafluoropropanol solution was applied by spinner and the thickness was 900
Was formed. Then, a thickness of 1
A 200 ° gold reflective layer was provided, and a 7 μm thick protective layer was further formed thereon using an acrylic photopolymer.
Finally, an injection-molded polycarbonate planar substrate having a thickness of 0.6 mm was bonded with an acrylic photopolymer to obtain an optical recording medium.

Examples 2 to 20 Compound No. 1 used in Example 1 Compound No. 1 in place of Compound No.
Using Nos. 2 to 20, an optical recording medium was produced in exactly the same manner as in Example 1.

Comparative Example 1 Compound No. 1 used in Example 1 An optical recording medium was prepared in exactly the same manner as in Example 1, except that the following compound was used in place of 1.

Embedded image

Examples 1 to 20 prepared as described above
And a laser oscillation wavelength of 65 for the optical recording medium of Comparative Example 1.
EFM signal (linear velocity 3.5 m / sec) while tracking using a semiconductor laser beam having a beam diameter of 8 nm and a beam diameter of 1.0 μm.
c. ) Was recorded and then reproduced using continuous light (reproduction power 0.7 mW) of a semiconductor laser having an oscillation wavelength of 685 nm, the reproduced waveform was observed, and the following weathering test was performed. <Weather resistance test conditions> Light resistance test: 40,000 Lux, Xe light, continuous irradiation for 20 hours Storage test: 60 ° C., 90%, left for 600 hours The measurement results are shown in Table 4 below.

[0030]

[Table 4]

[0031]

According to the first to third aspects of the present invention, it is possible to provide 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, high coating properties and storage stability.
According to the fourth and fifth aspects of the present invention, it is possible to provide an optical recording medium capable of performing high-density recording with low jitter. According to the sixth aspect, it is possible to provide an optical recording medium capable of performing more stable recording and reproduction. According to the seventh aspect, it is possible to provide an optical recording / reproducing method capable of performing stable recording / reproducing with high reflectance and high modulation degree.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a main weight loss process of an organic material and a method of obtaining a weight loss rate.

FIG. 2 is a diagram illustrating an example of a layer configuration of a normal write-once optical recording medium. (A) shows a basic configuration including a substrate and a recording layer. (B) shows a configuration in which an undercoat layer is provided between the substrate and the recording layer. (C) A configuration in which a protective layer is further provided on the recording layer is shown. (D) A configuration in which a hard coat layer is further provided on the back surface of the substrate is shown.

FIG. 3 is a diagram showing a layer configuration example of an optical recording medium for CD-R. (A) shows a basic configuration provided with a substrate, a recording layer, a metal reflection layer, and a protective layer. (B) A configuration in which an undercoat layer is further provided between the substrate and the recording layer is shown. (C) A configuration in which a hard coat layer is further provided on the back surface of the substrate is shown.

FIG. 4 is a diagram illustrating a layer configuration example of an optical recording medium for DVD-R. (A) shows a basic configuration provided with a substrate, a recording layer, a metal reflection layer, and a protective layer. (B) A configuration in which a protective substrate is further provided on the protective layer via an adhesive layer. (C) A configuration in which an undercoat layer is further provided between the substrate and the recording layer, and a hard coat layer is provided on the back surface of the substrate.

Continued on the front page (72) Inventor Tatsuya Tomura 1-3-6 Nakamagome, Ota-ku, Tokyo Ricoh Co., Ltd. (72) Inventor Somu 1-3-6 Nakamagome, Ota-ku, Tokyo Ricoh Co., Ltd. F term (reference) 2H111 FA01 FB42 5D029 JA04 JC05 JC06 WB11 WB14 WD10

Claims (7)

[Claims] 1. An optical recording medium comprising a recording layer provided on a substrate, and an azo compound represented by the general formula (I) in the recording layer and an azo metal chelate dye compound comprising a metal, a metal oxide or a salt thereof. An optical recording medium comprising at least one of the following. Embedded image In the general formula (I), the ring A together with the carbon atom and the nitrogen atom to which it is attached, is derived from pyrrole, imidazole, pyrazole, triazole, tetrazole, indole, isoindole, benzimidazole, indazole, purine, perimidine Represents a residue forming a heterocyclic ring selected from the group consisting of: M represents a metal or a metal oxide; R ₁ and R ₂ each independently represent a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group; And R ₃
To R ₆ each independently represent a hydrogen atom, a halogen atom, a nitro group, a cyano group, a hydroxyl group, a carboxyl group, an amino group,
Substituted or unsubstituted alkyl group, substituted or unsubstituted aryl group, substituted or unsubstituted heterocyclic residue, substituted or unsubstituted alkylcarbonyl group, substituted or unsubstituted arylcarbonyl group, substituted or unsubstituted alkyl Oxycarbonyl group, substituted or unsubstituted aryloxycarbonyl group, substituted or unsubstituted alkylsulfonyl group, substituted or unsubstituted arylsulfonyl group, substituted or unsubstituted alkylthiooxy group, substituted or unsubstituted arylthiooxy group ,
Substituted or unsubstituted alkyloxy group, substituted or unsubstituted aryloxy group, substituted or unsubstituted alkylamino group, substituted or unsubstituted arylamino group, substituted or unsubstituted alkylcarbonylamino group, substituted or unsubstituted Represents a substituted or unsubstituted alkylcarbamoyl group, a substituted or unsubstituted arylcarbamoyl group, a substituted or unsubstituted alkenyl group, and n represents 2 or 3. R ₂ and R ₃ , R ₃ and R ₄ , R ₄ and R
₅ may be linked to form a ring. Note that R ₁ and R ₂ do not represent a hydrogen atom. 2. The optical recording medium according to claim 1, wherein the valence of the metal is divalent or trivalent. 3. The method according to claim 1, wherein the metal is one of manganese, cobalt, nickel, and copper.
The optical recording medium according to the above. 4. The thermogravimetric analysis of the azo metal chelate dye compound (organic dye) constituting the recording layer, wherein the ratio of weight loss to temperature in the main weight loss process is 2% / ° C. or more. Item 4. The optical recording medium according to any one of Items 1 to 3. 5. The thermogravimetric analysis of the azo metal chelate dye compound (organic dye) constituting the recording layer, the total weight loss in the main weight loss process is 30% or more, and the weight loss start temperature is 200 to 500%.
The optical recording medium according to claim 1, wherein the temperature is 350 ° C. 6. A track pitch on the substrate is 0.7 to 0.7.
0.8 μm, and the groove width is half width at 0.18 to 0.3
The optical recording medium according to claim 1, wherein the thickness is 6 μm. 7. The single layer of the recording layer has a refractive index n of 1.5 ≦ n ≦ 3.0 and a extinction coefficient k of 0.02 ≦ k ≦ with respect to light in a wavelength range of ± 5 nm. An optical recording / reproducing method using the optical recording medium according to any one of claims 1 to 6.