JP2002370451A - Optical recording medium, optical recording method and optical recording apparatus using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a recording material in an optical recording medium applicable to a DVD-R disk system using a semiconductor laser having an oscillation wavelength shorter than a conventional system, in particular, squarylium Provided are a recording material having excellent light resistance and storage stability in an optical recording medium using a metal chelate compound, a recording method using the recording material, and a recording apparatus. SOLUTION: In an optical recording medium having a recording layer provided on a substrate, a squarylium metal chelate compound comprising a squarylium compound and a metal in the recording layer; And / or the following general formula II An optical recording medium containing at least one formazan compound represented by the formula (1) and a formazan metal chelate compound comprising a metal.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a large-capacity write-once optical disc for data (for example, a large-capacity write-once compact disc, DVD-R), an optical recording method, and an optical recording apparatus.

[0002]

2. Description of the Related Art a. (For information recording) write-once recording medium (W
ORM)

(1) Using a cyanine dye as a recording material JP-A-57-82093, 58-56892, 58-1
12790, 58-114989, 59-85791,
60-83236, 60-89842, 61-2588
6

(2) Using a phthalocyanine dye as a recording material JP-A-61-150243, 61-177287, 61
154888, 61-246091, 62-3928
6,63-37991,63-39888

B. Write-once compact disc (CD-
R) Conventional technology

(1) A recording material comprising a cyanine dye and a metal reflection layer: JP-A-1-159842, 2-42652, 2-136
56, 2-168446

(2) Using a phthalocyanine dye + metal reflective layer as a recording material: JP-A-1-176585, 3-215466, 4-11
3886, 4-226390, 5-1272, 5-17
1052, 5-116456, 5-96860, 5-1
39044

(3) Using an azo metal chelate dye and a metal reflection layer as a recording material: Japanese Patent Application Laid-Open No. 4-46186, 4-141489, 4-361
088, 5-279580, 7-51673, 7-16
1069, 7-37272, 7-71867, 8-23
1866,8-295811

C. Large capacity write-once compact disc (D
VD-R)

(1) Using cyanine dye + metal reflective layer as recording material PIONER R & D vol. 6 No. Two, one
996: Development of DVD-Recordable, DVD
Basic development of -R dye disk ISOM / ODS'96, 1996: High de
nsity of recording on Dye
material Disc approach f
or 4.7G JP-A-10-235999

(2) Using an azomethine dye and a metal reflective layer as a recording material: Japanese Patent Application Laid-Open No. 8-198872, 8-209012, 8-28
3263, 10-273484

(3) Using an azo metal chelate dye + metal reflective layer as a recording material JP-B-5-67438, JP-A-7-16069, 8-
156408, 8-231866, 8-333772
9-58123, 9-175031, 9-19354
5,9-277432,9-277703,10-66
44, 10-6650, 10-6651, 10-366
93, 10-44606, 10-58828, 10-8
6519, 10-149584, 10-157293.
10-157300, 10-157301, 10-15
7302, 10-181199, 10-181201,
10-181203, 10-181206, 10-18
8340, 10-188341, 10-188358,
10-208303, 10-214423, 10-22
8671,11-12483

(4) A recording material comprising a styryl dye and a metal reflection layer: Japanese Patent Application Laid-Open No. Hei 10-15854, 10-188338, 11
-34489, 11-99746, 11-99747,
11-144313, 11-165466

(5) Using formazan dye + metal reflective layer as a recording material Japanese Patent No. 2791944, JP-A-8-295079, 9
-95520, 9-193546, 10-15186
2,10-151863,10-15223,10-
154350, 10-337958

(6) Other recording materials using a dye and a metal reflection layer as described in JP-A-10-86517, 10-93788, 10-2
26172,10-244752,10-28781
9,10-297103,10-309871,10-
309872

As seen from the above, many optical recording media have been proposed, but DVD-Rs are now being developed as next-generation large-capacity optical disks. As elemental technologies for improving the recording capacity, it is necessary to develop recording materials for miniaturizing recording pits, adopt image compression technology represented by MPEG2, and shorten the wavelength of semiconductor lasers for reading recording pits. is there.

Heretofore, as a semiconductor laser in the red wavelength region, 670 nm band Al has been used for bar code readers and measuring instruments.
Although only GaInP laser diodes have been commercialized, red lasers are being used in the optical storage market in earnest as the density of optical disks increases. DVD
In the case of a drive, the light source is standardized by the wavelength of a laser diode in the 630 to 690 nm band. On the other hand, a read-only DVD-ROM drive is commercialized at a wavelength of about 650 nm.

A squarylium metal chelate compound is one of the recording layers of an optical recording medium for recording and reproducing by an optical pickup using a laser having a wavelength of 630 to 690 nm. However, this compound is remarkably deteriorated by light and has poor stability.
A dye having high light resistance is a formazan metal chelate compound. However, a medium using this dye in a recording layer has a problem such as low reflectance.

[0019]

SUMMARY OF THE INVENTION The present invention relates to a recording material in an optical recording medium applicable to a DVD-R disk system using a semiconductor laser having an oscillation wavelength shorter than that of the conventional system, in particular, squarylium. An object of the present invention is to provide a recording material having excellent light resistance and storage stability in an optical recording medium using a metal chelate compound, an optical recording method using the recording material, and an optical recording device.

[0020]

As a result of various studies on means for solving the above-mentioned problems, the present inventors have found that, in particular, the light stability and the absorption coefficient are improved by chelating a squarylium compound with a metal. So you can
By using a mixture of a dye having these structures and a formazan metal chelate compound as a main component as a recording layer, it is applicable to a next-generation large-capacity optical disk system using a semiconductor laser having an oscillation wavelength of 690 nm or less, and The present inventors have found that an optical recording medium having excellent light resistance and storage stability can be obtained, and have reached the present invention.

That is, a first aspect of the present invention is to provide an optical recording medium having a recording layer provided on a substrate, wherein a squarylium metal chelate compound comprising a squarylium compound and a metal in the recording layer is represented by the following general formula (I):

[0022]

Embedded image [In the formula, Z represents a residue forming a substituted or unsubstituted 5- or 6-membered heterocyclic ring containing a nitrogen atom. Another aromatic ring may be condensed with the nitrogen-containing heterocyclic ring. A is an alkyl group which may have a substituent, an aryl group which may have a substituent, an alkylcarbonyl group which may have a substituent, and an arylcarbonyl which may have a substituent And a alkenyl group which may have a substituent, a heterocyclic residue which may have a substituent, an alkoxycarbonyl group which may have a substituent and the like. B represents an alkyl group which may have a substituent, an alkenyl group which may have a substituent, an aryl group which may have a substituent, and the like. And / or the following general formula (II)

[0023]

Embedded image [In the formula, Z ₁ and Z ₂ each represent a residue forming a substituted or unsubstituted 5- or 6-membered heterocyclic ring containing a nitrogen atom. Another aromatic ring may be condensed with the nitrogen-containing heterocyclic ring. A ₁ and A ₂ each have an alkyl group which may have a substituent, an aryl group which may have a substituent, an alkylcarbonyl group which may have a substituent, and a substituent An arylcarbonyl group which may be substituted, an alkenyl group which may have a substituent, a heterocyclic residue which may have a substituent, an alkoxycarbonyl group which may have a substituent, and the like. B ₁ and B ₂ each represent an alkylene group which may have a substituent, an arylene group which may have a substituent or the like. W is -CH ₂ - representing the - or -SO _2. n is an integer of 0 or 1. ], And at least one formazan metal chelate compound comprising a metal.

The second aspect of the present invention relates to an optimum mixing ratio of the squarylium metal chelate compound and the formazan metal chelate compound. The weight ratio of the squarylium metal chelate compound to the formazan metal chelate compound is 90:10 to 5:
0:50 in the first optical recording medium.

The third aspect of the present invention relates to an optimum metal species of the formazan metal chelate compound, wherein the metal atom of the formazan metal chelate compound is vanadium, manganese, iron, cobalt, nickel, copper, zinc, palladium or an oxide or oxide thereof. In the first and second optical recording media which are halides.

A fourth aspect of the present invention relates to an optimum structure of the squarylium metal chelate compound, wherein the squarylium metal chelate compound has the following general formula (III):

Embedded image [Wherein, R ₁ and R ₂ are the same or different and each have a hydrogen atom, an alkyl group which may have a substituent, an aralkyl group which may have a substituent, Represents an aryl group or a heterocyclic group which may have a substituent. M represents a metal atom having coordination ability. m represents an integer of 2 or 3. X represents an optionally substituted aryl group, a heterocyclic group, or Z ₃ = CH- (Z ₃ represents a heterocyclic group which may have a substituent). ] In the first to third optical recording media.

The fifth aspect of the present invention relates to a more optimal structure of the squarylium metal chelate compound, wherein X in the general formula (III) represents the following general formula (IV)

Embedded image Wherein, R ₃ and R ₄ are the same or different, or represents an alkyl group which may have a substituent, or R ₃
And R ₄ together with adjacent carbon atoms may form an alicyclic hydrocarbon ring or a heterocyclic ring. R ₅ represents a hydrogen atom, an alkyl group which may have a substituent, an aralkyl group which may have a substituent, or an aryl group which may have a substituent. R ₆ represents a halogen atom, an alkyl group which may have a substituent, an aralkyl group which may have a substituent, an aryl group which may have a substituent, a nitro group, a cyano group, or substituted represents also alkoxy group, n represents an integer of 0 to 4, when n is 2 to 4, R ₆ is which may be identical or different, two adjacent further each other R ₆ May combine with two adjacent carbon atoms to form an aromatic ring which may have a substituent. ] In the fourth optical recording medium.

A sixth aspect of the present invention relates to an optimum metal species of the squarylium metal chelate compound, and the fourth or fifth optical recording medium in which the metal M is aluminum.

The seventh aspect of the present invention relates to the limitation of the optical characteristics of the dye mixture which can be recorded and reproduced with high reflectance and high modulation.
The refractive index n of the recording layer single layer with respect to light in the wavelength range of recording / reproducing wavelength ± 5 nm is 1.5 ≦ n ≦ 3.0, and the extinction coefficient k
Is 0.02 ≦ k ≦ 0.3 in the first to sixth optical recording media.

An eighth aspect of the present invention relates to an optimum reflecting layer condition for high-density media to be applied, which has a reflecting layer, and the reflecting layer contains gold, silver, copper, aluminum, or an alloy of these metals. The optical recording media of 1 to 7 above.

A ninth aspect of the present invention relates to an optimum substrate guide groove condition for a high-density medium to be applied, wherein a track pitch on a substrate is 0.7 to 0.8 μm, a groove width is a half width, and
The optical recording medium according to any one of the first to eighth optical recording media having a thickness of 8 to 0.40 μm.

A tenth aspect of the present invention relates to the limitation of a recording wavelength for a high-density medium, which is the first to ninth optical recording media recordable at a recording wavelength of 600 to 720 nm.

An eleventh aspect of the present invention relates to a recording method using a limited wavelength.
An optical recording method is characterized in that recording is performed at a recording wavelength of 0 to 720 nm.

According to a twelfth aspect of the present invention, there is provided an optical recording apparatus having any one of the first to tenth optical recording media mounted thereon.

[0035]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail. The present invention is characterized in that the squarylium metal chelate compound and the formazan metal chelate compound are used in combination, wherein the mixing ratio of the squarylium metal chelate compound and the formazan metal chelate compound in an optical recording medium, 90:10 to 50:
Preferably it is 50. It is preferable that it is in the above range in terms of light resistance and reflectance.

First, the formazan metal chelate compound will be described. The substituents Z, Z ₁ and Z ₂ in the general formulas (I) and (II) represent a residue forming a substituted or unsubstituted 5- or 6-membered heterocyclic ring containing a nitrogen atom. ,
A, B, A ₁ , A ₂ , B ₁ and B ₂ each represent a substituent bonded to the position shown in the general formulas (I) and (II). W is -CH ₂ - represents or -SO _2, and when n = 0, and B ₁ and B ₂ are directly bonded.

Specific examples of Z, Z ₁ and Z ₂ include thiazole ring, benzothiazole ring, imidazole ring, benzimidazole ring, thiadiazole ring, oxazole ring, benzoxazole ring, triazole ring, pyrazole ring,
Residues forming an oxadiazole ring, a pyridine ring, a pyridazine ring, a pyrimidine ring, a pyrazine ring, a triazine ring, a quinoline ring and the like can be mentioned. These nitrogen-containing heterocycles
It may have a substituent or another aromatic ring may be condensed.

Specific examples of the above substituents are each independently a hydrogen atom, a halogen atom, a nitro group, a cyano group,
Hydroxyl group, carboxyl group, amino group, carbamoyl group,
An alkyl group which may have a substituent, an aryl group which may have a substituent, a heterocyclic residue which may have a substituent, an alkoxy group which may have a substituent, An aryloxy group optionally having a substituent, an alkylthio group optionally having a substituent, an arylthio group optionally having a substituent, an alkylamino group optionally having a substituent, Arylamino group which may have a substituent, alkoxycarbonyl group which may have a substituent, aryloxycarbonyl group which may have a substituent, alkyl which may have a substituent A carboxamide group, an arylcarboxamide group which may have a substituent, an alkylcarbamoyl group which may have a substituent, an arylcarbamoyl group which may have a substituent, An alkenyl group, and an alkyl sulfamoyl group may have a substituent.

Specific examples of A, A ₁ and A ₂ include an alkyl group which may have a substituent, an aryl group which may have a substituent, and an alkyl group which may have a substituent. Examples include a carbonyl group, an arylcarbonyl group which may have a substituent, and an alkoxycarbonyl group which may have a substituent.

Specific examples of B include an alkyl group which may have a substituent, an alkenyl group which may have a substituent, and an aryl group which may have a substituent.

Specific examples of B ₁ and B ₂ include an alkylene group which may have a substituent and an arylene group which may have a substituent.

Specific examples of the alkyl group include those having 1 to 1 carbon atoms.
5, for example, a methyl group, an ethyl group, n
-Propyl group, n-butyl group, n-pentyl group, n-hexyl group, n-heptyl group, n-octyl group, n-nonyl group, n-decyl group and other linear alkyl groups, 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-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-methylbutyl group, neopentyl group, tert-butyl group, tert-hexyl group, tert-amyl group, t
branched alkyl groups such as tert-octyl group, cyclohexyl group, 4-methylcyclohexyl group, 4-ethylcyclohexyl group, 4-tert-butylcyclohexyl group, 4- (2-ethylhexyl) cyclohexyl group, bornyl group, isobornyl group ( And a cycloalkyl group such as an adamantyl group, among which those having 1 to 8 carbon atoms are preferable. Examples of the alkylene group include those obtained by removing one hydrogen atom from the above-mentioned alkyl group.

The alkyl group is a hydroxyl group, a halogen atom, a nitro group, a carboxyl group, a cyano group, or an aryl which may have a specific substituent (for example, may be substituted by a halogen atom or a nitro group). It may be substituted with a group, a heterocyclic residue or the like. Further, it 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 methoxypropyl group and an ethoxypropyl group. Examples of the alkyl group substituted via sulfur include a methylthioethyl group, an ethylthioethyl group, an ethylthiopropyl group, and a phenylthioethyl group.
Examples include a dimethylaminoethyl group, a diethylaminoethyl group, a diethylaminopropyl group, and the like.

Specific examples of the alkenyl group include those having 2 carbon atoms.
6 to vinyl, allyl, 1-propenyl, methacrylic, crotyl, 1-butenyl, 3-
Butenyl group, 2-pentenyl group, 4-pentenyl group, 2
-Hexenyl group, 5-hexenyl group and the like. Examples of the substituent of the alkenyl group include the same substituents as those of the alkyl group described above.

Specific examples of the aryl group include a phenyl group, a naphthyl group, an anthryl group, a fluorenyl group, a phenalenyl group, a phenanthranyl group, a triphenylenyl group, a pyrenyl group and the like.

Examples of the arylene group include those obtained by removing one hydrogen atom from the aryl group.

The aryl group is an alkyl group, a hydroxyl group,
Halogen atom, nitro group, carboxyl group, cyano group,
A trifluoromethyl group, an aryl group which may have a specific substituent (for example, may be substituted with a halogen atom or a nitro group), a heterocyclic residue, or the like; , Sulfur, nitrogen or the like, may be substituted with the above-mentioned alkyl group.

Specific examples of the heterocyclic residue include a furyl group,
Thienyl, pyrrolyl, benzofuranyl, isobenzofuranyl, benzothienyl, indolinyl, isoindolinyl, carbazolyl, pyridyl, piperidyl, quinolyl, isoquinolyl, oxazolyl, isoxazolyl, thiazolyl, isothiazolyl Groups, imidazolyl groups, pyrazolyl groups, benzimidazolyl groups, pyrazyl groups, pyrimidinyl groups, pyridazinyl groups, quinoxalinyl groups and the like.

The heterocyclic residue may have a hydroxyl group, a halogen atom, a nitro group, a carboxyl group, a cyano group, or a specific substituent (for example, it may be substituted with a halogen atom or a nitro group). ) It may be substituted with an aryl group, a heterocyclic residue which may have a substituent, or the like, or may be substituted with the above-mentioned alkyl group via an atom such as oxygen, sulfur, or nitrogen.

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

Specific examples of the alkoxy group which may have a substituent include those in which an alkyl group which may have a substituent is directly bonded to an oxygen atom. The above-mentioned specific examples can be mentioned as specific examples.

Specific examples of the aryloxy group which may have a substituent may be any as long as the aryl group which may have a substituent is directly bonded to an oxygen atom. Specific examples of the group include the specific examples described above.

Specific examples of the alkylthio group which may have a substituent may be any one in which an alkyl group which may have a substituent is directly bonded to a sulfur atom. The above-mentioned specific examples can be mentioned as specific examples.

Specific examples of the arylthio group which may have a substituent may be any as long as an aryl group which may have a substituent is directly bonded to a sulfur atom. The above-mentioned specific examples can be mentioned as specific examples.

Specific examples of the alkylamino group which may have a substituent may be any as long as the alkyl group which may have a substituent is directly bonded to a nitrogen atom. Specific examples of the group include the specific examples described above. Further, the alkyl groups may be bonded to each other to form a ring containing an oxygen atom, a nitrogen atom, and the like, such as a piperidino group, a morpholino group, a pyrrolidinyl group, a piperazinyl group, an indolinyl group, and an isoindolinyl group.

Specific examples of the arylamino group which may have a substituent may be any one in which an aryl group which may have a substituent is directly bonded to a nitrogen atom. Specific examples of the group include the specific examples described above.

Specific examples of the alkylcarbonyl group which may have a substituent may be any as long as the alkyl group which may have a substituent is directly bonded to the carbon atom of the carbonyl group. Specific examples of the group and the substituent include those described above.

Specific examples of the arylcarbonyl group which may have a substituent may be any as long as the aryl group which may have a substituent is directly bonded to the carbon atom of the carbonyl group. Specific examples of the group and the substituent include those described above.

Specific examples of the optionally substituted alkoxycarbonyl group include those in which an optionally substituted alkyl group is directly bonded to the oxygen atom of O (C ＝ O). The specific examples of the alkyl group and the substituent include the specific examples described above.

A specific example of the optionally substituted aryloxycarbonyl group is a group in which an optionally substituted aryl group is directly bonded to the oxygen atom of O (C ＝ O). Specific examples of the aryl group and the substituent include those described above.

Specific examples of the alkylcarboxamide group which may have a substituent may be any as long as the alkyl group which may have a substituent is directly bonded to the carbon atom of carboxamide. Specific examples of the substituent and the above-described specific examples can be given.

Specific examples of the arylcarboxamide group which may have a substituent may be any as long as the aryl group which may have a substituent is directly bonded to the carbon atom of carboxamide. Specific examples of the substituent and the above-described specific examples can be given.

Specific examples of the alkylcarbamoyl group which may have a substituent may be any as long as the alkyl group which may have a substituent is directly bonded to the nitrogen atom of the carbamoyl group. Specific examples of the group and the substituent include those described above. Further, the alkyl groups may be bonded to each other to form a ring containing an oxygen atom, a nitrogen atom, and the like, such as a piperidino group, a morpholino group, a pyrrolidinyl group, a piperazinyl group, an indolinyl group, and an isoindolinyl group.

Specific examples of the arylcarbamoyl group which may have a substituent may be any as long as the aryl group which may have a substituent is directly bonded to the nitrogen atom of the carbamoyl group. Specific examples of the group and the substituent include those described above.

Specific examples of the alkylsulfamoyl group which may have a substituent may be any as long as the alkyl group which may have a substituent is directly bonded to the nitrogen atom of the sulfamoyl group. Specific examples of the alkyl group and the substituent include those described above.

Specific examples of the metal atom in the formazan metal chelate compound include titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc, zirconium, niobium, molybdenum, technetium, ruthenium, rhodium, palladium, Oxides or halides, etc., especially vanadium,
Formazan metal chelate compounds of manganese, iron, cobalt, nickel, copper, zinc and palladium have excellent optical properties as optical recording materials. Among the halides, chlorides are preferably used.

Next, the squarylium metal chelate compound will be described. In the optical recording medium of the present invention, it is preferable to use a laser beam having a recording / reproducing wavelength of 600 to 720 nm. From the optical characteristics at this wavelength, among the squarylium metal chelate compounds, those represented by the general formula (III) are particularly preferable. Is preferred.

[0069]

Embedded image [Wherein, R ₁ and R ₂ are the same or different and each have a hydrogen atom, an alkyl group which may have a substituent, an aralkyl group which may have a substituent, And a heterocyclic group which may have a substituent. M represents a metal atom having coordination ability. m is 2
Alternatively, it represents an integer of 3. X represents an aryl group which may have a substituent, a heterocyclic group which may have a substituent, or Z ₃ ＣＨCH- (Z ₃ represents a heterocyclic group which may have a substituent. ). ]

X in the general formula (III) is preferably represented by the following general formula (IV).

[0071]

Embedded image [Wherein, R ₃ and R ₄ are the same or different and each represent an optionally substituted alkyl group or the like;
₃ and R ₄ together with adjacent carbon atoms may form an alicyclic hydrocarbon ring or a heterocyclic ring. R ₅ represents a hydrogen atom, an alkyl group which may have a substituent, an aralkyl group which may have a substituent, an aryl group which may have a substituent, or the like. R ₆ represents a halogen atom, an alkyl group which may have a substituent, an aralkyl group which may have a substituent, an aryl group which may have a substituent, a nitro group, a cyano group, or a substituted Represents an alkoxy group or the like which may have a group, n represents an integer of 0 to 4,
When n is 2 to 4, R ₆ may be the same or different;
Further, two adjacent R ₆ may be combined with two adjacent carbon atoms to form an aromatic ring which may have a substituent. ]

In the definition of the substituent in the formula (III) or (IV), the alkyl moiety in the alkyl group and the alkoxy group may be a straight-chain or branched alkyl group having 1 to 6 carbon atoms or 3 to 6 carbon atoms. 8 cyclic alkyl groups and the like, for example, methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group,
c-butyl group, tert-butyl group, pentyl group, isopentyl group, 1-methylbutyl group, 2-methylbutyl group, tert-pentyl group, hexyl group, cyclopropyl group, cyclobutyl group, cyclopentyl group, cyclohexyl group, cycloheptyl group , Cyclooctyl group and the like.

Examples of the aralkyl group include aralkyl groups having 7 to 15 carbon atoms, such as benzyl, phenethyl, phenylpropyl and naphthylmethyl.

Examples of the aryl group include a phenyl group, a naphthyl group, an anthryl group and an azulenyl group.

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

The substituents on the aralkyl group, the aryl group, the alkoxy group, the aromatic ring or the heterocyclic group may be the same or different and may have 1 to 5 substituents, for example, a hydroxyl group, a carboxyl group, a halogen atom, an alkyl group, Examples thereof include an alkoxy group, a nitro group, and an amino group which may have a substituent. Examples of the halogen atom, the alkyl group and the alkoxy group include the same as those described above.

Examples of the substituent of the alkyl group include the same or different and one to three substituents such as a hydroxyl group, a carboxyl group, a halogen atom and an alkoxy group.
Examples of the halogen atom and the alkoxy group include the same as described above.

Examples of the substituent for the amino group include the same or different and one or two alkyl groups, and the alkyl group in this case is the same as described above.

Examples of metal atoms having coordination ability include aluminum, zinc, copper, iron, nickel, chromium,
Cobalt, manganese, iridium, vanadium, titanium and the like can be mentioned. Among them, copper, aluminum and nickel are preferable. Particularly, a squarylium metal chelate compound of aluminum has excellent optical properties as an optical recording material.

Examples of the aromatic ring formed by two adjacent R ₆ , together with two adjacent carbon atoms, include a benzene ring.

Examples of the heterocyclic ring in the heterocyclic group other than the heterocyclic group in Z ₃ of the general formula (III), or the heterocyclic ring formed by R ₃ and R ₄ together with adjacent carbon atoms include, for example, nitrogen A 5- or 6-membered monocyclic aromatic or aliphatic heterocyclic ring containing at least one atom selected from an atom, an oxygen atom and a sulfur atom, a 3- or 8-membered fused bicyclic or tricyclic ring Examples include a condensed aromatic or aliphatic heterocycle containing at least one atom selected from a nitrogen atom, an oxygen atom and a sulfur atom, and more specifically, a pyridine ring, a pyrazine ring, a pyrimidine ring, a pyridazine ring, Quinoline ring, isoquinoline ring, phthalazine ring, quinazoline ring, quinoxaline ring, naphthyridine ring, cinnoline ring,
Pyrrole ring, pyrazole ring, imidazole ring, triazole ring, tetrazole ring, thiophene ring, furan ring, thiazole ring, oxazole ring, indole ring, isoindole ring, indazole ring, benzimidazole ring, benzotriazole ring, benzothiazole ring, benzo Oxazole ring, purine ring, carbazole ring, pyrrolidine ring, piperidine ring, piperazine ring, morpholine ring, thiomorpholine ring, homopiperidine ring, homopiperazine ring,
Examples include a tetrahydropyridine ring, a tetrahydroquinoline ring, a tetrahydroisoquinoline ring, a tetrahydrofuran ring, a tetrahydropyran ring, a dihydrobenzofuran ring, and a tetrahydrocarbazole ring.

The heterocyclic group represented by Z _{3 in} the general formula (III) includes
Indoline-2-ylidene, benz [e] indoline-
2-ylidene, 2-benzothiazolinylidene, naphtho [2,1-d] thiazole-2 (3H) -ylidene, naphtho [1,2-d] thiazole-2 (1H) -ylidene, 1,4- Dihydroquinoline-4-ylidene, 1,2
-Dihydroquinoline-2-ylidene, 2-benzoselenazolinylidene and the like.

Examples of the alicyclic hydrocarbon ring formed by R ₃ and R ₄ together with adjacent carbon atoms include those having 3 to 8 carbon atoms, and those having a saturated or unsaturated structure are preferred. Well, for example, cyclopropane ring, cyclobutane ring, cyclopentane ring, cyclohexane ring, cycloheptane ring,
Examples include a cyclooctane ring, a cyclopentene ring, a 1,3-cyclopentadiene ring, a cyclohexene ring, a cyclohexadiene ring, and the like.

Next, a general method for producing the compound (III) will be described.

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[0085]

Embedded image

[0086]

Embedded image

[0087]

Embedded image [Wherein, R ₁ , R ₂ , X, M and m are as defined above, Y represents hydrogen, potassium, sodium and the like, and Me represents methyl. ]

In the above reaction formula (1-a), compound (VII) is prepared by combining compound (V) with 0.5 to 2 moles of compound (VI) in the presence of a base, if necessary, in a solvent at room temperature. ~ 40
It is obtained by reacting at 30 ° C for 30 minutes to 15 hours.
As the base, for example, an inorganic base such as potassium carbonate, sodium carbonate, or potassium hydroxide or an organic base such as triethylamine or sodium methoxide is used.
As the solvent, for example, methanol, ethanol, dimethylformamide and the like are used.

In the above reaction formula (1-b), compound (VIII) can be obtained by treating compound (VII) in an alkaline solvent or an acidic solvent at room temperature to 40 ° C. for 30 minutes to 15 hours. As the alkaline solvent, for example, an aqueous potassium carbonate solution, an aqueous sodium carbonate solution, an aqueous potassium hydroxide solution and the like are used. As the acidic solvent,
For example, a 50% volume / volume aqueous dimethyl sulfoxide solution of hydrochloric acid, a 50% volume / volume dimethylformamide aqueous solution of hydrochloric acid, and the like are used.

In the above reaction formula (1-c), the compound (IX) is 0.5 to 2 times the molar amount of the compound (VIII)
And, if necessary, in the presence of 0.5 to 2 moles of a base in a solvent at 80 to 120 ° C for 1 to 15 hours. As the solvent, for example, only an alcoholic solvent having 2 to 8 carbon atoms such as ethanol, propanol, isopropanol, butanol, octanol, or a mixed solvent of the alcoholic solvent and benzene, toluene or xylene (alcohol 50 vol / vol%) that's all)
Are used. As the base, for example, an organic base such as quinoline, triethylamine, pyridine or the like, or an inorganic base such as potassium carbonate, potassium hydrogen carbonate, sodium hydrogen carbonate or the like is used.

In the above reaction formula (1-d), compound (III) is obtained by converting compound (IX) with 0.5 to 2 times Mm ⁺ by 0.5 to 2 times mol, if necessary. In the presence of acetic acid,
It is obtained by reacting at room temperature to 120 ° C. for 1 to 15 hours in a solvent. As a raw material that gives M ^{m +} , for example, aluminum trisacetylacetonate, aluminum trisethylacetoacetate, aluminum isoproxide, aluminum sec-butoxide, aluminum ethoxide, aluminum chloride, copper chloride, copper acetate, nickel acetate and the like are used. Can be Examples of the solvent include halogen solvents such as chloroform and dichloromethane, aromatic solvents such as toluene and xylene, ether solvents such as tetrahydrofuran and methyl-tert-butyl ether, and ester solvents such as ethyl acetate.

The physical properties required for the recording layer material include optical characteristics, thermal characteristics, and light resistance.

As optical characteristics, the recording / reproducing wavelength of a DVD-R or the like is 600 to 720 nm, preferably 630 to 720 nm.
It is preferable to have a large absorption band on the short wavelength side with respect to 690 nm, and to have the recording / reproducing wavelength near the long wavelength end of the absorption band. This is the recording / reproducing wavelength of 600 to 72.
At 0 nm, it means that the recording layer material has a large refractive index and a predetermined extinction coefficient. In particular,
In the wavelength range of the recording / reproducing wavelength ± 5 nm near the long wavelength end of the absorption band, it is preferable that the refractive index n of the recording layer single layer is 1.5 or more and 3.0 or less and larger, and the extinction coefficient k
Is preferably in the range of 0.02 or more and 0.3 or less. When n is 1.5 or more, a sufficient optical change can be obtained, so that the reflectance and the recording modulation degree become higher. Therefore, when n is 3.0 or less, the wavelength dependency is high. However, it is preferable that a reproduction error does not easily occur with light in the recording / reproduction wavelength region. When k is 0.02 or more,
It is preferable because recording sensitivity is improved. When k is 0.3 or less, a reflectance of 50% or more is more easily obtained, which is preferable.
Further, the maximum absorption wavelength (λmax) measured in a chloroform solution state is preferably in the range of 550 to 600 nm, and since the refractive index n can be increased as the extinction coefficient increases, its log ε (ε is the molar extinction coefficient) ) Is preferably 5 or more.

As a thermal characteristic, the decomposition temperature is preferably in a specific temperature range. Specifically, the decomposition temperature is 350
C. or lower is preferable, and those in the range of 250 to 350C are more preferable. When the decomposition start temperature is 350 ° C. or lower, it is not necessary to increase the power of the recording laser beam, and when it is 250 ° C. or higher, it is preferable in terms of recording stability.

Further, as light resistance, it is preferable to have reproduction stability of 1,000,000 times or more of repetition and fastness to prevent fading when left indoors.

The substrate usually has a guide groove having a depth of 1000 to 2500 °. Track pitch is usually 0.7
.About.1.0 μm, but 0.7.about.
0.8 μm is preferred. Groove width is 0.18 ~ at half width
0.40 μm is preferred. A thickness of 0.18 μm or more is preferable because sufficient tracking error signal intensity can be obtained. When the thickness is 0.40 μm or less, it is preferable that the recording portion hardly spreads laterally upon recording.

Next, the configuration of the optical recording medium of the present invention will be described. FIG. 1 is a diagram showing an example of a layer configuration applicable to the optical recording medium of the present invention, which is an example of a write-once optical disc.
The recording layer 2 is provided on the substrate 1 via an undercoat layer 3 as necessary, and a protective layer 4 is further provided as necessary. If necessary, a hard coat layer 5 may be formed under the substrate 1.
Can be provided.

FIG. 2 is a diagram showing another example of a layer structure applicable to the optical recording medium of the present invention, which is an example of a CD-R medium. A metal reflective layer 6 is provided on the recording layer 2 having the configuration shown in FIG.

FIG. 3 is a view showing an example of a layer structure of another type (for DVD-R) applicable to the optical recording medium of the present invention. In this case, an adhesive is formed on the protective layer 4 having the structure of FIG. A layer 8 and a protective substrate 7 are provided.

That is, in the optical recording medium of the present invention, the recording layer (organic thin film layer) having the structure shown in FIGS.
An air sandwich structure hermetically sealed with a space between other substrates can be used, or a laminated structure bonded with a protective layer can be used.

When the optical recording medium of the present invention is applied to a DVD-R, the optical recording medium includes a first substrate and a second substrate (hereinafter sometimes referred to as a first substrate and a second substrate). Are laminated with an adhesive via a recording layer as a basic structure. The recording layer may be a single layer of an organic dye, or a laminate of an organic dye layer and a metal reflective layer to enhance the reflective layer. The recording layer and the substrate may be layered with an undercoat layer or a protective layer interposed therebetween, or may be formed by laminating them for improving the function.
The most commonly used structure is a first substrate / organic dye layer / metal reflective layer / protective layer / adhesive layer / second substrate structure.

(Substrate) As a necessary characteristic of the substrate, the substrate must be transparent to the laser beam used only when recording and reproduction are performed from the substrate side, and the substrate must be transparent when recording and reproduction are performed from the recording layer side. There is no. Therefore, in the present invention, when two substrates are used in a sandwich shape, for example, if only one substrate (the second substrate) is transparent, the other substrate (the first substrate) may be transparent or opaque. . As a substrate material, for example, plastic such as polyester, acrylic resin, polyamide, polycarbonate resin, polyolefin resin, phenol resin, epoxy resin, and polyimide, glass, ceramic, or metal can be used. When only one layer of the substrate is used, on the surface of the substrate, when two substrates are used in a sandwich form, on the surface of the first substrate, guide grooves and guide pits for tracking, as well as address signals and the like are provided. A format may be formed.

(Recording Layer) The recording layer causes some optical change by laser light irradiation, and can record information by the change. In this recording layer, a dye mixture [squarylium] which is a feature of the present invention is contained. A mixture of a metal chelate compound and a formazan metal chelate compound represented by the above general formula (I) and / or (II)]. Specific examples of the compound represented by the general formula (I) or (II) are shown in Tables 1 to 3, and specific examples of the squarylium metal chelate compound represented by the general formula (III) are shown in Tables 4 to 6. . In the following table, nPr is n-
Represents propyl, iPr represents isopropyl, nBu
Represents an n-butyl group, and Ph represents a phenyl group.

[Table 1]

[Table 2]

[Table 3]

[Table 4]

[Table 5]

[Table 6]

In the formation of the recording layer, the above-mentioned dye mixture which is a feature of the present invention may be used singly or in combination. Further, in addition to the dye mixture characteristic of the present invention, another organic dye may be mixed or laminated for the purpose of improving optical characteristics, recording sensitivity, signal characteristics, and the like.

Examples of such other organic dyes include polymethine dyes, naphthalocyanine dyes, phthalocyanine dyes, squarylium dyes, croconium dyes, pyrylium dyes, naphthoquinone dyes, anthraquinone (indanethrene) dyes, xanthene dyes and triphenyl dyes. Examples thereof include methane-based, azulene-based, tetrahydrocholine-based, phenanthrene-based, triphenothiazine-based dyes, and metal chelate compounds. These dyes may be used alone or in combination of two or more.

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.

Further, various materials such as ionomer resins, polyamide resins, vinyl resins, natural polymers, silicones, liquid rubbers and the like, or silane coupling agents are dispersed and mixed in the dye mixture. May be used, or a stabilizer (for example, a transition metal complex), a dispersant, a flame retardant, a lubricant, an antistatic agent,
Surfactants, plasticizers and the like can be used together.

The recording layer is formed by vapor deposition, sputtering, C
It can be carried out by ordinary means such as VD or solution application. When using the coating method, the dye mixture and the like are dissolved in an organic solvent or the like, and spraying, roller coating,
It is performed by a conventional coating method such as dipping and spin coating.

As the organic solvent used, generally, methanol, ethanol, isopropanol, 2,2,3,3
Alcohols such as tetrafluoropropanol, ketones such as acetone, methyl ethyl ketone and cyclohexanone, amides such as N, N-dimethylformamide, N, N-dimethylacetamide, sulfoxides such as dimethyl sulfoxide, tetrahydrofuran, dioxane;
Ethers such as 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; benzene, xylene and monochlorobenzene , Aromatics such as dichlorobenzene, cellosolves such as methoxyethanol and ethoxyethanol, hexane,
Hydrocarbons such as pentane, cyclohexane, and methylcyclohexane are exemplified.

The thickness of the recording layer is preferably 100 to 10
μm, more preferably 200 ° to 2000 °.

(Undercoat layer) The undercoat layer comprises (a) an improvement in adhesiveness, (b) a barrier against water or gas, (c) an improvement in storage stability of the recording layer, and (d) an improvement in reflectance. It is used for the purpose of (e) protection of the substrate and the recording layer from a solvent, and (f) formation of guide grooves, guide pits, preformats and the like.

For the purpose of (a), a polymer material such as an ionomer resin, a polyamide resin, a vinyl resin,
Various polymer substances such as natural resins, natural polymers, silicones, liquid rubbers, and silane coupling agents can be used. For the purposes (b) and (c), other than the above-mentioned polymer materials are used. Inorganic compounds such as SiO ₂ and Mg
F ₂ , SiO, TiO ₂ , ZnO, TiN, SiN, etc., and also a metal or semimetal such as Zn, Cu, Ni, C
r, Ge, Se, Au, Ag, Al and the like can be used. For the purpose of (d), a metal such as Al,
Ag or the like, or an organic thin film having a metallic luster such as a methine dye or a xanthene dye can be used. For the purposes (e) and (f), an ultraviolet curable resin, a thermosetting resin, a thermoplastic resin, etc. Can be used.

The thickness of the undercoat layer is preferably 0.01 to 3
0 μm, more preferably 0.05 to 10 μm is suitable.

(Metal Reflective Layer) Examples of the material of the metal 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, and the like.
Examples thereof include Cr, Ni, Al, Fe, Sn, and Cu. Au, Ag, Al, and Cu are most preferable in terms of reflectance and productivity, and these metals and metalloids may be used alone. Alternatively, two or more alloys may be used. Examples of the method for forming the film of the metal reflection layer include vapor deposition and sputtering, and the film thickness is preferably 50 to 5000 °, more preferably 1 to 500 °.
It is 00 to 3000 °.

(Protective Layer, Hard Coat Layer on Substrate Surface) The protective layer or hard coat layer on the substrate surface is composed of (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. For these purposes, the materials shown in the undercoat layer can be used.
In addition, SiO, SiO _{2 and the} like can be used as inorganic materials, and polymethyl acrylate, polycarbonate, epoxy resin, polystyrene, polyester resin, vinyl resin, cellulose, aliphatic hydrocarbon resin, aromatic hydrocarbon resin, and the like can be used as organic materials. Natural rubber, styrene butadiene resin, chloroprene rubber, wax, alkyd resin, drying oil, heat softening resin such as rosin, heat melting resin, ultraviolet curable resin and the like can also be used. The most preferable example of the protective layer or the substrate 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 preferably 0.01 to 30 μm, more preferably 0.1 to 30 μm.
It is suitably from 05 to 10 μm.

In the present invention, a stabilizer, a dispersant, a flame retardant, a lubricant, an antistatic agent, and a surfactant are provided in the undercoat layer, the protective layer, and the hard coat layer on the substrate surface as in the case of the recording layer. , A plasticizer and the like.

(Protective Substrate) When the protective substrate is irradiated with laser light from the protective substrate side, it must be transparent to the laser light to be used.
Transparency does not matter. Usable materials are exactly the same as the above-mentioned substrate materials, and plastics such as polyester, acrylic resin, polyamide, polycarbonate resin, polyolefin resin, phenol resin, epoxy resin, polyimide, or glass, ceramic or metal are used. Can be.

(Adhesive, Adhesive Layer) Any material can be used as long as it can bond two recording media. Considering productivity, an ultraviolet-curable or hot-melt adhesive is preferable.

[0120]

The present invention will be specifically described below with reference to examples and comparative examples. The compounds used in Examples and Comparative Examples are those described in Tables 1 to 6.

(Example 1) Compound Examples A-4 and B- 4 (the mixing ratio is shown in Table 7).
Was dissolved in 2,2,3,3-tetrafluoropropanol, and the solution was spinner-coated to a thickness of 100
An organic dye layer of 0 ° was formed, and then a reflective layer of 1300 ° of gold was provided by sputtering, and a 5 μm protective layer of acrylic photopolymer was provided thereon. Furthermore, the thickness is 0.
A 6 mm injection molded polycarbonate substrate was bonded with an acrylic photopolymer to obtain an optical recording medium.

(Examples 2 to 10) Optical recording media were formed in exactly the same manner as in Example 1 using the raw materials having the combinations shown in Table 7.

Comparative Example 1 An optical recording medium was formed in exactly the same manner as in Example 1 except that only the compound B-1 which was a squarylium metal chelate compound was used.

Table 7 shows the evaluation results of these optical recording media. <Recording conditions> These optical recording media have an oscillation wavelength of 658 n.
m, an EFM signal (linear velocity: 3.5 m / sec) is recorded while tracking using a semiconductor laser beam having a beam diameter of 1.0 μm, and reproduced by continuous light (reproduction power: 0.7 mW) of a semiconductor laser having an oscillation wavelength of 658 nm. Then, the reproduced waveform was observed.

<Weather resistance test conditions> Light resistance test: 40,000 Lux, Xe light, continuous irradiation for 20 hours Storage test: 50 ° C., 80% RH, left for 800 hours

(Evaluation results)

[0127]

[Table 7]

[0128]

1) Claims 1, 2, 3, 4, 5, 6 and 10 Optical recording which is recordable and reproducible with a laser beam in a wavelength range of 600 to 720 nm, and has excellent light resistance and storage stability. Media could be provided. In particular, it has become possible to provide an optical recording medium having excellent light resistance as compared with a single squarylium metal chelate compound. 2) Claims 7 and 8 In addition to the first effect, an optical recording medium capable of recording and reproducing with a stable high reflectance and a high degree of modulation could be provided. 3) Claim 9 In addition to the first effect, an optical recording medium capable of performing stable recording and reproduction can be provided. 4) Claim 11 An optical recording method having the effects of the first to tenth optical recording media can be provided. 5) Claim 12 It has become possible to provide an optical recording apparatus having the first effect.

[Brief description of the drawings]

FIGS. 1A to 1D are schematic cross-sectional views of examples of the layer configuration of a write-once optical disc applicable to the recording medium of the present invention.

FIGS. 2A to 2C are schematic cross-sectional views of a layer configuration example of a CD-R medium applicable to the recording medium of the present invention.

FIGS. 3A to 3C are schematic cross-sectional views of a layer configuration example of a DVD-R medium applicable to the recording medium of the present invention.

[Explanation of symbols]

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

Continuing on the front page (72) Inventor Mune Noguchi 1-3-6 Nakamagome, Ota-ku, Tokyo Ricoh Co., Ltd. (72) Inventor Tsutomu 1-3-6 Nakamagome, Ota-ku, Tokyo Ricoh Co., Ltd. (72) Inventor Tatsuya Tomura 1-3-6 Nakamagome, Ota-ku, Tokyo Ricoh Co., Ltd. (72) Inventor Yasunobu Ueno 1-3-6 Nakamagome, Ota-ku, Tokyo Ricoh Co., Ltd. (72) Invention Person Ikuo Shimizu 2-3-3, Daikyo-cho, Yokkaichi-shi, Mie Pref., Kyowa Yuka Co., Ltd.Yokkaichi Research Institute (72) Inventor Motoharu Kinugasa 2-3-3, Daikyo-cho, Yokkaichi-shi, Mie Pref. 72) Inventor Hiroshi Toyoda 2-3-3, Daikyocho, Yokkaichi-shi, Mie Kyowa Yuka Co., Ltd.Yokkaichi Research Institute (72) Inventor Shiho Yamada 2-3-3, Daikyocho, Yokkaichi-shi, Mie Kyowa Yuka Research Co., Ltd. In-house F-term (reference) 2H111 EA03 EA12 EA22 EA39 EA40 FA01 FA12 FA23 FA31 FB30 FB42 FB48 5D029 JA04 JC05 JC06 JC17 MA13 WB11 WB14 WC01 WD30

Claims (12)

[Claims] 1. An optical recording medium comprising a recording layer provided on a substrate, a squarylium metal chelate compound comprising a squarylium compound and a metal in the recording layer, and a compound represented by the following general formula (I): [In the formula, Z represents a residue forming a substituted or unsubstituted 5- or 6-membered heterocyclic ring containing a nitrogen atom. Another aromatic ring may be condensed with the nitrogen-containing heterocyclic ring. A is an alkyl group which may have a substituent, an aryl group which may have a substituent, an alkylcarbonyl group which may have a substituent, and an arylcarbonyl which may have a substituent Represents a group, an alkenyl group which may have a substituent, a heterocyclic residue which may have a substituent, or an alkoxycarbonyl group which may have a substituent.
B represents an alkyl group which may have a substituent, an alkenyl group which may have a substituent, or an aryl group which may have a substituent. And / or the following general formula (II): [In the formula, Z ₁ and Z ₂ each represent a residue forming a substituted or unsubstituted 5- or 6-membered heterocyclic ring containing a nitrogen atom. Another aromatic ring may be condensed with the nitrogen-containing heterocyclic ring. A ₁ and A ₂ each have an alkyl group which may have a substituent, an aryl group which may have a substituent, an alkylcarbonyl group which may have a substituent, and a substituent An arylcarbonyl group which may be substituted, an alkenyl group which may have a substituent, a heterocyclic residue which may have a substituent, or an alkoxycarbonyl group which may have a substituent. B ₁ and B ₂ each represent an alkylene group which may have a substituent or an arylene group which may have a substituent. W is -CH ₂ - representing the - or -SO _2. n is an integer of 0 or 1. An optical recording medium comprising at least one formazan metal chelate compound comprising a formazan compound and a metal. 2. A squarylium metal chelate compound and a formazan metal chelate compound in a weight ratio of 90:10 to 5
2. The optical recording medium according to claim 1, wherein the ratio is 0:50. 3. The method according to claim 1, wherein the metal atom of the formazan metal chelate compound is at least one selected from the group consisting of vanadium, manganese, iron, cobalt, nickel, copper, zinc, palladium, and oxides or halides thereof. The optical recording medium according to claim 1 or 2, wherein 4. A squarylium metal chelate compound represented by the following general formula (III): [Wherein, R ₁ and R ₂ are the same or different and each have a hydrogen atom, an alkyl group which may have a substituent, an aralkyl group which may have a substituent, Represents an aryl group or a heterocyclic group which may have a substituent. M represents a metal atom having coordination ability. m represents an integer of 2 or 3. X is an aryl group which may have a substituent, a heterocyclic group which may have a substituent,
Or Z ₃ ＣＨCH— (Z ₃ represents a heterocyclic group which may have a substituent). The optical recording medium according to any one of claims 1 to 4, wherein: 5. X in the general formula (III) is represented by the following general formula (I
V) Wherein, R ₃ and R ₄ are the same or different, or represents an alkyl group which may have a substituent, or R ₃
And R ₄ together with adjacent carbon atoms may form an alicyclic hydrocarbon ring or a heterocyclic ring. R ₅ represents a hydrogen atom, an alkyl group which may have a substituent, an aralkyl group which may have a substituent or an aryl group which may have a substituent. R ₆ is a halogen atom, an alkyl group which may have a substituent, an aralkyl group which may have a substituent, an aryl group which may have a substituent, a nitro group, a cyano group or a substituent And n represents an integer of 0 to 4. When n is 2 to 4, R ₆ may be the same or different, and two adjacent R ₆ are adjacent to each other. Together with the two carbon atoms to form an aromatic ring which may have a substituent. The optical recording medium according to claim 4, wherein: 6. The optical recording medium according to claim 4, wherein M is aluminum. 7. A recording layer having a refractive index n of 1.5 ≦ n ≦ 3.0 and a extinction coefficient k of 0.02 ≦ k ≦ 0 with respect to light in a wavelength range of ± 5 nm. The optical recording medium according to claim 1, wherein the number is 3. 8. A reflective layer having a reflective layer, the reflective layer comprising gold, silver, copper,
The optical recording medium according to any one of claims 1 to 7, comprising aluminum or an alloy of these metals. 9. The track pitch on the substrate is 0.7-0.
8 μm, and the groove width is 0.18 to 0.40 μm in half width.
The optical recording medium according to claim 1, wherein: 10. The optical recording medium according to claim 1, wherein recording is possible at a wavelength of 600 to 720 nm. 11. An optical recording method comprising recording on the optical recording medium according to claim 1 at a recording wavelength of 600 to 720 nm. 12. An optical recording apparatus on which the optical recording medium according to claim 1 is mounted.