JP2002011950A - Optical recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical recording medium, in which information is recorded and reproduced by developing optical changes such as the changes of the transmittance, reflectivity or the like of recording material through the irradiation of light beams and additional recording is possible and which is excellent in light resistance suitable for a high density optical disc system (DVD-R) employing a semiconductor laser having oscillating wavelength in shorter wavelength and storage stability. SOLUTION: In this optical recording medium, a recording layer including a specified formazane metal chelate coloring matter thereon is provided on a board.

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, and more particularly, to a method of irradiating an optical recording medium with a light beam.
An information recording medium that causes optical changes such as transmittance and reflectance of a recording material to record and reproduce information, and that is recordable, and uses a semiconductor laser having an oscillation wavelength at a shorter wavelength. High-density optical disk system (DVD
The present invention relates to an optical recording medium suitable for -R) and having excellent light resistance and storage stability.

[0002]

2. Description of the Related Art At present, as a next-generation large-capacity optical disk,
DVD-R development is underway. The factors for improving the recording capacity are the development of recording materials for miniaturizing recording pits, MP
The technical development includes the adoption of image compression technology represented by EG2 and the shortening of the wavelength of a semiconductor laser for reading recorded pits.

Hitherto, as a semiconductor laser in the red wavelength range, a 670 nm A laser has been used for a bar code reader and a measuring instrument.
Although only the 1GaInP laser diode has been developed and commercialized, a red laser has recently been used in the optical storage market in earnest as the density of optical discs increases. In the case of a DVD drive, the light source is 6
It is standardized by two wavelengths, 35 nm band and 650 nm band laser diode. For high-density recording, the wavelength is desirably shorter, and for a write-once media drive, the wavelength is preferably 635 nm. On the other hand, a read-only DVD-ROM drive is commercialized at a wavelength of ６650 nm.

Under such circumstances, the most preferable DVD-
R media is a medium (DVD-R) that can record and reproduce at a wavelength of up to 635 nm and can reproduce at a wavelength of up to 650 nm, and has excellent light resistance and storage stability.
There is a demand for a recording material that can be recorded and reproduced by an optical pickup using a laser of 0 nm or less.

Recently, as such recording materials, polymethine dyes (JP-A-10-83577, JP-A-10-83577)
JP-A-19434, JP-A-10-149584, JP-A-10-188339, JP-A-10-2
No. 78426) and azo metal chelate dyes (Japanese Unexamined Patent Publication No.
JP-A-295811, JP-A-8-295812, JP-A-9-332772, JP-A-9-393
No. 94, JP-A-10-6650, JP-A-10
-58828, JP-A-10-157293, JP-A-10-157300, JP-A-10-1
88340, JP-A-10-188341)
The development of the one using is progressing.

However, among the polymethine dyes, in particular, cyanine dyes and squarylium dyes are excellent in optical properties, and although satisfactory signal characteristics can be obtained, they have extremely poor light fastness and cannot withstand practical use by themselves. There was nothing. For this reason, light stabilizers have been developed (Japanese Patent Application Laid-Open Nos. 10-109475, 10-109476, 10-134413).
At present, there has not yet been found any device that achieves both light resistance and signal characteristics. Also, when an azo metal chelate dye was used, the signal characteristics were satisfactory, but sufficient light fastness was not obtained.

Further, a formazan metal chelate dye is
It is known that the light stability is extremely high, and its application as an optical recording material has been attempted.
5079, JP-A-10-152623 and JP-A-10-154350), both of which have a long absorption wavelength and are not suitable as DVD-R recording materials. Its application as a light stabilizer for cyanine dyes has also been attempted, but since the light stabilization mechanism is based on the transfer of excitation energy from the main dye to the light stabilizer, more efficient light stabilizers include: The formazan metal chelate dye has an absorption wavelength that is too long and cannot exhibit sufficient light stabilizing ability. Was.

[0008]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned conventional disadvantages and provides a light-resistant optical system applicable to a high-density optical disk system using a semiconductor laser having an oscillation wavelength shorter than that of the conventional system. It is an object of the present invention to provide an optical recording medium for a DVD-R which is excellent in stability and storage stability.

[0009]

Means for Solving the Problems In order to solve the above-mentioned problems, the present inventors have conducted intensive studies focusing on light stabilization of the recording layer. As a result, a specific formazaan metal chelate dye was added to the recording layer. It has been found that by containing the same, an optical recording medium excellent in light resistance and storage stability can be obtained, and the present invention has been completed based on this finding.

That is, according to the present invention, there is provided an optical recording medium comprising a recording layer provided on a substrate, wherein the recording layer contains a compound represented by the following general formula (1). Is provided.

Embedded image [Wherein, Z ₁ and Z ₂ each represent a group which forms a heterocyclic ring together with a carbon atom and a nitrogen atom to which they are bonded;
₁ , A ₂ represents an alkyl group, an aralkyl group, an aryl group or a cyclohexyl group, B ₁ and B ₂ represent an aryl group, and X represents a methylene group, a sulfone group or a group having no group (B ₁ and B ₂ are directly bonded).
Represents a divalent metal atom].

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention is an optical recording medium having a recording layer provided on a substrate. In the optical recording medium of the present invention, the recording layer may be provided directly on the substrate or via an undercoat layer, and a reflective layer on the recording layer,
It may be provided with a protective layer or an adhesive layer and a second substrate.

The substrate used in the present invention must be transparent to the laser used only when recording / reproducing from the substrate side. When recording / reproducing from the recording layer side,
It does not need to be transparent. Examples of the substrate material include plastics such as polyester, acrylic resin, polyamide, polycarbonate, polyolefin, phenol resin, epoxy resin, and polyimide, glass, ceramic, and metal. Note that a guide groove for tracking, a pre-format of a guide pit or an address signal, or the like may be formed on the surface of the substrate. The thickness of this substrate is usually about 0.6 μm.

The recording layer is a layer containing a light-absorbing dye that causes some optical change by irradiation with a laser beam and records information by the change. In the present invention, a so-called air sandwich structure (write-once optical disk structure) in which two recording layers are provided on a substrate may be used, and a recording layer, a reflective layer, and a protective layer are provided on the substrate. The structure (CD-R structure) may be used. Also,
It may be one in which a CD-R structure is bonded.

[0014] The undercoat layer includes an adhesive layer, a barrier against water or gas, an improvement in storage stability of the recording layer, an improvement in reflectivity, protection of the substrate from a solvent, guide grooves, guide pits, and a preformat. It is a layer formed for the purpose of formation and the like. For the purpose of the polymer material, for example, ionomer resin, polyamide resin, vinyl resin,
It is formed using various high molecular compounds such as natural resin, natural polymer, silicone, liquid rubber, or a silane coupling agent. In addition to the above polymer materials, inorganic compounds such as SiO, MgF, Si
With O ₂ , TiO, ZnO, TiN, SiN, etc., a metal or metalloid such as Zn, Cu, Ni, Cr,
It is formed of Ge, Se, Au, Ag, Al or the like.
For this purpose, metals such as Al, Au, Ag and the like, and organic thin films having metallic luster such as methine dyes and xanthene dyes are used. For the purposes (1) and (2), it is formed using an ultraviolet curable resin, a thermosetting resin, a thermoplastic resin, or the like. The thickness of this undercoat layer is usually
0.01 to 30 μm, preferably 0.05 to 10 μm
It is.

The reflection layer is made of a metal, a semi-metal, or the like which gives a high reflectance by itself and is not easily corroded. Examples of the material include Au, Ag, Cr, Ni, Al, Fe,
Sn and the like. From the viewpoint of reflectivity and productivity, Au,
Ag and Al are most preferred. These metals and metalloids may be used alone or as an alloy of two or more. As a layer forming method, vapor deposition, sputtering, etc. are adopted, and the thickness of the layer is 50 to 5000 °, preferably 100 to 3000 °.

[0016] The protective layer can be used to damage the recording layer (reflection / absorption layer).
This layer is formed for the purpose of protecting the recording layer from dust, dirt, and the like, improving the storage stability of the recording layer, and improving the reflectance. For these purposes, the materials shown in the undercoat layer can be used. Also,
As inorganic materials, SiO, SiO ₂ etc., as organic materials, polymethyl acrylate, polycarbonate, epoxy resin, polystyrene, polyester, vinyl resin,
Thermosoftening and heat melting resins such as cellulose, aliphatic hydrocarbon resin, natural rubber, styrene-butadiene resin, chloroprene rubber, wax, alkyd resin, drying oil and rosin can also be used. Among these materials, excellent productivity of radical polymerization type acrylic resin, unsaturated polyester resin, unsaturated polyurethane resin, cationic photopolymerization type aryldiazonium salt, diaryliodonium salt, dialkylphenacylsulfonium salt, sulfonic acid ester, etc. UV cured resin is the most preferred material. The thickness of this protective layer is 0.01 to 30 μm, preferably 0.05 to 10 μm.

In the present invention, a hard coat layer on the substrate surface can be provided in order to enhance the scratch resistance of the substrate surface, and the material and the thickness of this layer are the same as those of the protective layer.

The above-mentioned recording layer, undercoat layer, protective layer and substrate hard coat layer can contain stabilizers, dispersants, flame retardants, lubricants, antistatic agents, surfactants, plasticizers and the like. .

The present invention relates to such an optical recording medium, wherein the recording layer contains a compound represented by the following general formula (1).

Embedded image [Wherein, Z ₁ and Z ₂ each represent a group which forms a heterocyclic ring together with a carbon atom and a nitrogen atom to which they are bonded;
₁ , A ₂ represents an alkyl group, an aralkyl group, an aryl group or a cyclohexyl group, B ₁ and B ₂ represent an aryl group, and X represents a methylene group, a sulfone group or a group having no group (B ₁ and B ₂ are directly bonded).
Represents a divalent metal atom].

The recording layer causes some optical change by laser light irradiation, and records information based on the change. In the present invention, the recording layer is represented by the above general formula (1). Need to contain at least one compound.

As Z ₁ and Z ₂ , thiazole ring, benzothiazole ring, oxazole ring, benzoxazole ring, pyrazole ring, benzopyrazole ring, imidazole ring, benzimidazole ring, oxadiazole ring, triazole ring, thiadiazole ring, pyridazine And a ring, a pyrimidine ring, a pyrazine ring, a triazine ring and the like. These may have an alkyl group, an alkoxy group, a thioalkoxy group, a substituted amino group, an aryl group, an aryloxy group, an anilino group or a keto group as a substituent. Among them, a pyridine ring, a pyridazine ring, a pyrimidine ring, a pyrazine ring, and a triazine ring are particularly preferable from the viewpoint of optical properties, storage stability, and light resistance.

As B ₁ and B ₂ , phenyl, pentalenyl, indenyl, naphthyl, azulenyl, heptalenyl, biphenylenyl, as-indacenyl, s-indacenyl, acenaphthalenyl,
Examples thereof include a fluorenyl group, a phenalenyl group, a phenanthranyl group, an anthranyl group, a fluoracenyl group, an acephenanthrenyl group, an aceanthrylene group, a triphenylenyl group, a pyrenyl group, a chrysenyl group, and a naphthacenyl group. These may have an alkyl group, an alkoxy group, a halogen atom, a carboxyl group or its ester group, a nitrile group, or a nitro group as a substituent.

Examples of the alkyl group 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, an n-nonyl group, a primary alkyl group such as an 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, 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, 1-isobutyl-3-
Secondary alkyl group such as methylbutyl group, neopentyl group,
tert-butyl group, tert-hexyl group, tert
-Amyl group, tertiary alkyl group such as tert-octyl group, cyclohexyl group, 4-methylcyclohexyl group,
Examples thereof include a cycloalkyl group such as a 4-ethylcyclohexyl group, a 4-tert-butylcyclohexyl group, a 4- (2-ethylhexyl) cyclohexyl group, a bornyl group, and an isobornyl group (adamantane group). These primary and secondary alkyl groups may be substituted with 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. Further, it may be substituted with the above-mentioned alkyl group via an atom such as oxygen, sulfur and 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, a piperidino group, a morpholino group, etc. Examples of the alkyl group in which an ethylthioethyl group, an ethylthiopropyl 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 include a phenyl group, a pentalenyl group, an indenyl group, a naphthyl group, an azulenyl group, a heptalenyl group, a biphenylenyl group, an as-indacenyl group, an s-indacenyl group, an acenaphthalenyl group,
Examples thereof include a fluorenyl group, a phenalenyl group, a phenanthranyl group, an anthranyl group, a fluoracenyl group, an acephenanthrenyl group, an aceanthrylene group, a triphenylenyl group, a pyrenyl group, a chrysenyl group, and a naphthacenyl group. These aryl groups may be substituted with 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, etc., and oxygen, sulfur, The alkyl group may be substituted through an atom such as nitrogen.

The alkoxy group may be any one in which a substituted or unsubstituted alkyl group is directly bonded to an oxygen atom, and examples of the alkyl group include those described above.

The above aryloxy group may be any one in which a substituted or unsubstituted aryl group is directly bonded to an oxygen atom, and examples of the aryl group include those described above.

Examples of the halogen atom include fluorine, chlorine, bromine and iodine.

As the metal atom M, titanium, vanadium, chromium, manganese, iron, cobalt, nickel,
Examples include copper, zinc, zirconium, niobium, molybdenum, technenium, ruthenium, rhodium, palladium, and the like. Among them, iron, cobalt, nickel, copper, zinc, and palladium are particularly preferable in terms of optical properties, storage stability, and light stability.

The compound represented by the above general formula (1) is
Only one kind may be used, or two or more kinds may be used in combination. Further, the compound represented by the above general formula (1) may be used by mixing or laminating with other organic dyes, metals, and metal compounds in order to improve optical characteristics, recording sensitivity, signal characteristics, and the like. Examples of organic dyes include polymethine dyes, naphthalocyanine dyes, phthalocyanine dyes,
Squarylium dye, croconium dye, pyrylium dye, naphthoquinone dye, anthraquinone dye (indanthrene dye), xanthene dye, triphenylmethane dye, azulene dye, tetrahydrocholine dye, phenanthrene dye, triphenothiazine dye and metal complex compounds thereof. Can be Metals and metal compounds include I
n, Te, Bi, Se, Sb, Ge, Sn, Al, B
e, TeO ₂ , SnO, As, Cd and the like, and each of them can be used in a form of being dispersedly mixed or laminated.

When the compound represented by the above general formula (1) is used as a stabilizer, it is used by mixing with a dye having an absorption maximum wavelength at 550 to 630 nm. In this case, the compound represented by the general formula (1) preferably has an absorption at a longer wavelength than the dye. 55
Preferred examples of the dye having an absorption maximum wavelength at 0 to 630 nm include polymethine dye, squarylium dye, croconium dye, pyrylium dye, naphthoquinone dye, anthraquinone dye (indanthrene type), xanthene dye, triphenylmethane dye, and tetrahydrocholine. Dyes, phenanthrene dyes, triphenothiazine dyes, azo metal chelate dyes and the like can be mentioned, and from the optical characteristics, polymethine dyes, squarylium dyes, and azo metal chelate dyes are particularly preferred.

Examples of the compound represented by the general formula (1) used in the present invention are shown in Tables 1 to 4.

[Table 1]

[Table 2]

[Table 3]

[Table 4]

Further, in the recording layer, various materials such as an ionomer resin, a polyamide resin, a vinyl resin, a natural polymer, silicone, a liquid rubber or a silane coupling agent are dispersed and mixed. Also, for the purpose of improving properties, 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 may be added.

As a method for forming the recording layer, a usual method such as vapor deposition, sputtering, CVD, or a solvent coating method can be employed. In the case of using a solvent coating method, the dye 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 speelane coating. Examples of the organic solvent used herein 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, ethers such as tetrahydrofuran, dioxane, diethyl ether and ethylene glycol monomethyl ether; esters such as methyl acetate and ethyl acetate; and aliphatic halogenated hydrocarbons such as chloroform, methylene chloride, dichloroethane, carbon tetrachloride and trichloroethane. , Aromatics such as benzene, xylene, monochlorobenzene and dichlorobenzene, cellosolves such as methoxyethanol and ethoxyethanol, hexane, pentane and cyclo Hexane, include hydrocarbons such as methylcyclohexane.

This recording layer has a thickness of 100 ° to 10 μm.
m, preferably 200 to 2000 °.

[0035]

The present invention will be described in more detail with reference to the following Examples, which should not be construed as limiting the present invention. Example 1 Compound No. 12 in Table 1 was dissolved in tetrafluoropropanol on a 0.6 mm thick injection molded polycarbonate substrate having a guide groove with a depth of 1600 °, a half width of 0.30 μm and a track pitch of 0.8 μm. The liquid is applied with a spinner to form a recording layer having a thickness of 800 、, and then a reflective layer of 2,000 設 け of gold is provided on the recording layer by a sputtering method. An optical recording medium was produced by providing a layer, and further laminating thereon a 0.6 mm injection molded polycarbonate substrate using an acrylic photopolymer.

Example 2 In place of Compound Example No. 12 in Example 1, Table 1 Compound Example No. An optical recording medium was produced in the same manner as in Example 1 except that No. 3 was used.

Example 3 In place of Compound Example No. 12 in Example 1, Table 1 Compound Example No. An optical recording medium was produced in the same manner as in Example 1 except that No. 8 was used.

Example 4 In place of Compound Example No. 12 in Example 1, Table 2 Compound Example No. An optical recording medium was produced in the same manner as in Example 1, except that 20 was used.

Example 5 In place of Compound No. 12 in Example 1, Table 3 Compound Example No. An optical recording medium was manufactured in the same manner as in Example 1, except that 36 was used.

Comparative Example 1 An optical recording medium was produced in the same manner as in Example 1 except that the compound represented by the following formula (i) was used in place of Compound Example No. 12 in Example 1.

Embedded image

Comparative Example 2 An optical recording medium was produced in the same manner as in Example 1, except that the compound represented by the following formula (ii) was used instead of Compound Example No. 12 in Example 1.

Embedded image

[Evaluation] A semiconductor laser beam having an oscillation wavelength of 658 nm was used for the optical recording medium thus manufactured.
While tracking, the EFM signal (linear velocity 3.0 m / s
ec, the shortest mark length of 0.4 μm) was recorded.
Continuous light of a 50 nm semiconductor laser (reproduction power 0.7
mW), and the reflectance and C / N were measured. The light fastness test was performed by irradiation with a tungsten lamp at 50,000 lux for 20 hours. Table 5 shows the results.

[Table 5]

Example 6 A compound represented by the above formula (i) and Compound No. 14 in Table 3 were placed on a 1.2 mm-thick injection-molded polycarbonate flat plate.
(Weight ratio of 10/3) was dissolved in tetrafluoropropanol, and a solution obtained by dissolving the mixture in a spinner was used.
An optical recording medium was manufactured by forming a recording layer of 00 °.

Example 7 Table 1 in Example 6 Table 1 was used instead of Compound No. 14
An optical recording medium was produced in the same manner as in Example 6, except that Compound No. 1 was used.

Example 8 Table 1 in Example 6 was replaced with Compound No. 14 in Table 1.
An optical recording medium was produced in the same manner as in Example 6, except that Compound No. 10 was used.

Example 9 Table 1 in Example 6 was replaced with Compound No. 14 in Table 1.
An optical recording medium was produced in the same manner as in Example 6, except that Compound No. 30 was used.

Example 10 An optical recording medium was produced in the same manner as in Example 6 except that the compound represented by the above formula (ii) was used instead of the compound represented by the above formula (i). Was prepared.

Comparative Example 3 An optical recording medium was produced in the same manner as in Example 6, except that only the compound represented by the above formula (i) was used.

Comparative Example 4 An optical recording medium was produced in the same manner as in Example 6, except that only the compound represented by the above formula (i) was used.

[Evaluation] The optical recording medium thus prepared was placed under a tungsten lamp at 50,000 lux, and the change in absorbance of the dye was measured. Table 6 shows the results.

[Table 6]

[0051]

According to the present invention, by irradiating a light beam, an optical change such as the transmittance and the reflectance of a recording material is caused, so that information can be recorded, reproduced, and additionally recorded. An optical recording medium having excellent light resistance and storage stability suitable for a high-density optical disk system (DVD-R) using a semiconductor laser having a shorter oscillation wavelength is provided. It is extremely important to contribute to the field of design and fabrication.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Noboru Sasa 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Company (72) Inventor Yasunobu Ueno 1-3-6 Nakamagome, Ota-ku, Tokyo Stock Ricoh Co., Ltd. (72) Inventor Yasuhiro Higashi 1-3-6 Nakamagome, Ota-ku, Tokyo Stock Company Ricoh Co., Ltd. (72) Katsuharu Maruyama 1403-15-808-808 F Reference) 2H111 EA03 EA12 EA22 EA25 EA32 EA39 EA40 EA43 FA01 FA12 FA14 FA15 FB42 FB43 FB63 5D029 JA04 JC17

Claims (7)

[Claims] An optical recording medium comprising a recording layer provided on a substrate, wherein the recording layer contains a compound represented by the following general formula (1). Embedded image [Wherein, Z ₁ and Z ₂ each represent a group which forms a heterocyclic ring together with a carbon atom and a nitrogen atom to which they are bonded;
₁ , A ₂ represents an alkyl group, an aralkyl group, an aryl group or a cyclohexyl group, B ₁ and B ₂ represent an aryl group, and X represents a methylene group, a sulfone group or a group having no group (B ₁ and B ₂ are directly bonded).
Represents a divalent metal atom]. 2. The optical recording medium according to claim 1, wherein the recording layer is provided on a substrate via a reflective layer, a protective layer or an adhesive layer, and a second substrate. 3. The optical recording medium according to claim 1, wherein Z in the general formula (1) is a pyridine ring, a pyridazine ring, a pyrimidine ring, a pyrazine ring, or a triazine ring. 4. The optical recording medium according to claim 1, wherein M in the general formula (1) is iron, cobalt, nickel, copper, zinc or palladium. 5. The optical recording medium according to claim 1, wherein the recording layer contains a light absorbing dye having a maximum absorption wavelength at 550 to 650 nm. 6. The optical recording medium according to claim 5, wherein the light absorbing dye is a polymethine dye, a squarylium dye, or an azo metal chelate dye. 7. The optical recording medium according to claim 6, wherein the polymethine dye is a cyanine dye.