JP2002370452A - Optical recording medium, optical recording method and optical recording device employing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a recording material in an optical recording medium appli cable to a DVD-R disc system employing a semiconductor laser having an oscillating wavelength shorter than the short wavelength employed in the conven tional system, especially the optical recording material excellent in light resis tance and storage stability in the optical recording medium employing a squalilum metal chelate compound, and also to provide the optical recording method and the optical recording device employing the same. SOLUTION: In the optical recording medium formed by providing a recording layer on a board, the recording layer includes at least each one kind of a squalilum compound, and of a formazan metal chelate compound consisting of a formazan compound represented by general formula (I) or general formula (II) and 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, JP-A-58-56892, JP-A-58-112790, JP-A-58-114989,
JP-A-59-85791, JP-A-60-83236, JP-A-60-89842, JP-A-61-25886

(2) Using a phthalocyanine dye as a recording material JP-A-61-150243, JP-A-61-17728
7, JP-A-61-154888, JP-A-61-2460
91, JP-A-62-39286, JP-A-63-3799
1, JP-A-63-39888

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

(1) Using a cyanine dye + metal reflective layer as a recording material JP-A-1-159842, JP-A-2-42652, JP-A-2-13656, JP-A-2-168446

(2) Using a phthalocyanine dye + metal reflective layer as a recording material JP-A-1-176585, JP-A-3-215466, JP-A-4-113886, JP-A-4-226390, JP-A-5-1272, JP-A-5-12772 5-171052;
116456, JP-A-5-96860, JP-A-5-13
9044

(3) Using azo metal chelate dye + metal reflection layer as recording material JP-A-4-46186, JP-A-4-141489, JP-A-4-36088, JP-A-5-279580, JP-A-7-51673, JP-A-7-16069, JP-A-7-160
37272, JP-A-7-71867, JP-A-8-231
866, JP-A-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 azomethine dye + metal reflective layer as recording material JP-A-8-198872, JP-A-8-209012, JP-A-8-283263, JP-A-10-273484

(3) A recording material comprising an azo metal chelate dye and a metal reflection layer JP-B 5-67438, JP-A-7-161609, JP-A-8-156408, JP-A-8-231866, JP-A-8-332772, JP-A-9-58123, JP-A-9-58123
175031, JP-A-9-193545, JP-A-9-2
74732, JP-A-9-277703, JP-A-10-6
644, JP-A-10-6650, JP-A-10-665
1, JP-A-10-36693, JP-A-10-4460
6, JP-A-10-58828, JP-A-10-8651
9, JP-A-10-149584, JP-A-10-1572
93, JP-A-10-157300, JP-A-10-157
301, JP-A-10-157302, JP-A-10-18
1199, JP-A-10-181201, JP-A-10-1
81203, JP-A-10-181206, JP-A-10-
188340, JP-A-10-188341, JP-A-10-188
188358, JP-A-10-208303, JP-A-1
0-214423, JP-A-10-228671, JP-A-11-12483

(4) A recording material comprising a styryl dye and a metal reflection layer: JP-A-10-151854, JP-A-10-18833
8, JP-A-11-34489, JP-A-11-9974
6, JP-A-11-99747, JP-A-11-14431
3, JP-A-11-165466

(5) Using formazan dye + metal reflective layer as recording material Japanese Patent No. 2791944; -151863, JP-A-10-152623, JP-A-10-154350, JP-A-10-337958

(6) Other recording materials using a dye and a metal reflective layer: JP-A-10-86517, JP-A-10-93788, JP-A-10-226172, JP-A-10-244758,
JP-A-10-287819, JP-A-10-29710
3, JP-A-10-309871, JP-A-10-3098
72

As seen above, many optical recording media have been proposed, and DVD-Rs are currently 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. Until now, only 670 nm band AlGaInP laser diodes have been commercialized as bar code readers and measuring instruments as semiconductor lasers in the red wavelength range. It is being used in the optical storage market. In the case of a DVD drive, 63
It is standardized by the wavelength of the laser diode in the band of 0 to 690 nm. On the other hand, a read-only DVD-ROM drive is commercialized at a wavelength of about 650 nm.

A squarylium compound is one of the recording layers of an optical recording medium for recording / reproducing with an optical pickup using a laser having a wavelength of 630 to 690 nm, but this compound is significantly 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.

[0018]

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 excellent in light resistance and storage stability in an optical recording medium using a compound, a recording method using the optical recording medium, and an optical recording device.

[0019]

As a result of investigations made by the present inventors, a recording layer mainly containing a mixture of a compound having a specific structure is used as a main component, whereby a next-generation semiconductor laser having an oscillation wavelength of 690 nm or less is used. The present inventors have found that an optical recording medium applicable to a large-capacity optical disk system and having excellent light resistance and storage stability can be obtained, and the present invention has been achieved.

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 compound is contained in the recording medium by the following general formula (I) and / or general formula (II). An optical recording medium comprising at least one formazan metal chelate compound comprising a formazan compound and a metal formazan metal chelate compound.

[0021]

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 aryl group which may have a substituent, or the like. ]

[0022]

Embedded image [Wherein, Z ₁ and Z ₂ each represent a substituted or unsubstituted 5- or 6-membered nitrogen-containing heterocyclic residue containing a nitrogen atom. Another aromatic ring may be condensed with the nitrogen-containing heterocyclic ring. A ₁ and A ₂ are an alkyl group optionally having a substituent, an aryl group optionally having a substituent, an alkylcarbonyl group optionally having a substituent,
An arylcarbonyl group which may have a substituent, an alkenyl group which may have a substituent, a heterocyclic residue which may have a substituent, or an alkoxy which may have a substituent Represents a carbonyl group or 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 - or -SO ₂ - represents a. m is an integer of 0 or 1. ]

The second aspect of the present invention relates to an optimum mixing ratio of the squarylium compound and the formazan metal chelate compound, wherein the squarylium compound and the formazan metal chelate compound have a weight ratio of 90:10 to 50:50. It is in.

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 halogen thereof. In the first and second optical recording media. Among the halides, chlorides are preferably used.

The fourth aspect of the present invention relates to the optimum structure of the squarylium compound, and the squarylium compound is a compound represented by the following general formula (III) and / or (VI). .

[0026]

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 optionally substituted aryl group or a heterocyclic residue which may have a substituent. Further, R ₁ and R ₂ may form a heterocyclic ring which may have a substituent together with an adjacent nitrogen atom. R ₃ represents the following general formula (IV) or (V):

[0027]

Embedded image (Wherein, R ₄ and R ₅ are the same or different and each represent a hydrogen atom or an alkyl group which may have a substituent, or R ₄ and R ₅ together with an adjacent nitrogen atom R ₆ , R ₇ , R ₈ and R ₉ may be the same or different and are each a hydrogen atom, an alkyl optionally substituted Group,
Represents an alkoxy group, a hydroxyl group, or a halogen atom which may have a substituent, and R ₄ and R ₆ , or R ₅ and R ₇ are taken together with an adjacent N—C—C to form a nitrogen-containing heterocyclic ring; May be formed, and the nitrogen-containing heterocyclic ring may have a substituent)

[0028]

Embedded image (In the formula, Q ₁ represents a carbon atom or a nitrogen atom, and R ₁₀ and R ₁₁ are the same or different and each have a hydrogen atom, an alkyl group which may have a substituent, A good aryl group, an optionally substituted aralkyl group or a hydroxyl group (provided that when Q ₁ is a nitrogen atom,
₁₁ represents not present), R ₁₂ represents a hydrogen atom, an optionally substituted alkyl group, an optionally substituted aryl group or an optionally substituted aralkyl group R ₁₃ and R ₁₄ are the same or different and each represent a hydrogen atom, an alkyl group which may have a substituent, an alkoxy group which may have a substituent, or a halogen atom; ₁₃ and R ₁₄ together with two adjacent carbon atoms form an alicyclic hydrocarbon ring, an optionally substituted aromatic ring or an optionally substituted heterocycle. It may be. ]

[0029]

Embedded image [Wherein Q ₂ represents a carbon atom or a nitrogen atom;
₁₅ represents a hydrogen atom, an alkyl group which may have a substituent, an aryl group which may have a substituent or a heterocyclic group which may have a substituent, and R ₁₆ is a hydrogen atom ,
A halogen atom, an alkyl group which may have a substituent,
An alkoxy group which may have a substituent, an aralkyl group which may have a substituent, an aryl group which may have a substituent, an amino group which may have a substituent or a substituent Represents a heterocyclic group which may have R ₁₇ and R ₁₈ are the same or different and each represents an alkyl group which may have a substituent, or R ₁₇ and R ₁₈ together with an adjacent carbon atom form an alicyclic hydrocarbon ring or A heterocyclic ring which may have a substituent may be formed. However, when Q ₂ is a nitrogen atom, R ₁₈ does not exist. R ₁₉ is a hydrogen atom,
Represents 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, and R ₂₀ has a halogen atom and a substituent An alkyl group which may be substituted, an aralkyl group which may have a substituent, an aryl group which may have a substituent, a trifluoromethyl group, a nitro group, a cyano group, or a group which has a substituent. Represents an alkoxy group. n represents an integer of 0 to 4, wherein, when n is 2 to 4, R ₂₀
It may be the same or different, may further form two aromatic rings which may have a substituent together with the carbon atom to which the two R ₂₀ adjacent to adjacent to each other. ]

The fifth aspect of the present invention relates to the limitation of the optical characteristics of the mixture (a mixture of a squarylium compound and a formazan metal chelate compound) which can be recorded and reproduced with a high reflectance and a high degree of modulation. In the first to fourth optical recording media, the refractive index n of the recording layer single layer with respect to light is 1.5 ≦ n ≦ 3.0, and the extinction coefficient k is 0.02 ≦ k ≦ 0.3. .

A sixth aspect of the present invention relates to an optimum reflecting layer condition for high-density media to be applied, wherein the reflecting layer has a reflecting layer and the reflecting layer comprises gold, silver, copper, aluminum, or an alloy of these metals. First to fifth optical recording media.

A seventh aspect of the present invention relates to an optimum substrate guide groove condition for a high-density medium to be applied, wherein the track pitch on the substrate is 0.7 to 0.8 μm, the groove width is a half width, and
In the above-mentioned first to sixth optical recording media having a thickness of 8 to 0.40 μm.

The eighth aspect of the present invention relates to the limitation of the recording wavelength for high-density media, which is the first to seventh optical recording media capable of recording at a recording wavelength of 600 to 720 nm.

The ninth aspect of the present invention relates to a recording method using a limited wavelength.
An optical recording method characterized by recording at a recording wavelength of 720 nm.

According to a tenth aspect of the present invention, there is provided an optical recording apparatus characterized by mounting the first to eighth optical recording media.

[0036]

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 compound and the formazan metal chelate compound are used in combination. In this case, the mixing ratio of the squarylium compound and the formazan metal chelate compound in the optical recording medium is 90:10 by weight. Preferably, the ratio is 50:50. It is preferable that it is in the above range in terms of light resistance and reflectance.

First, the definition of the groups in formulas (I) and (II) will be described. With respect to the definitions of the groups in the general formulas (I) and (II), Z, Z ₁ and Z ₂ are each a residue forming a substituted or unsubstituted 5- or 6-membered heterocyclic ring containing a nitrogen atom. And 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 represents —CH ₂ — or —SO ₂ —, provided that when m = 0 in the formula (II), 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. Carbonyl group, an arylcarbonyl group which may have a substituent, an alkenyl group which may have a substituent, a heterocyclic residue which may have a substituent, And a good alkoxycarbonyl group.

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

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 them, a cycloalkyl group having 1 to 8 carbon atoms is 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 through a sulfur include a methylthioethyl group, an ethylthioethyl group, an ethylthiopropyl group, and the like.Examples of the alkyl group substituted through a nitrogen include dimethylaminoethyl. Group, diethylaminoethyl group, diethylaminopropyl group and the like.

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. In addition, 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,
Trifluoromethyl, an aryl group which may have a specific substituent (for example, may be substituted by a halogen atom or a nitro group), may be substituted with a heterocyclic residue or the like; The alkyl group may be substituted via an atom such as sulfur or nitrogen.

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

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 arylcarbosamide group which may have a substituent include those having an aryl group which may have a substituent directly bonded to a carbon atom of carboxysamide. Frequently, specific examples of the aryl group and the substituent include the specific examples described above.

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 of 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 thereof, and the like, particularly vanadium, manganese, iron, cobalt, nickel, The formazan metal chelate compounds of copper, zinc and palladium have excellent optical properties as optical recording materials. Among the halides, chlorides are preferably used.

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 compounds, the general formulas (III) and (VI) Is preferably represented by

Next, the definitions of the groups in formulas (III) to (VI) will be described. In the definition of the groups represented by the general formulas (III) to (VI), the alkyl group in the alkyl group and the alkoxy group may be a straight-chain or branched carbon group having 1 carbon atom.
And a cyclic alkyl group having 3 to 8 carbon atoms, such as a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, and a
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.

The aryl group and the aryl moiety of the aralkyl group include, for example, a phenyl group, a naphthyl group, an anthryl group and the like.

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

The heterocyclic ring in the heterocyclic group and the heterocyclic ring formed by R ₁₃ and R ₁₄ or R ₁₇ and R ₁₈ together with adjacent (two) carbon atoms include aromatic heterocyclic ring and alicyclic ring. Formula heterocycles are mentioned.

Examples of the aromatic heterocyclic ring include a nitrogen atom,
A 5- or 6-membered monocyclic aromatic heterocyclic ring containing at least one atom selected from an oxygen atom and a sulfur atom;
A bicyclic or tricyclic condensed aromatic heterocyclic ring containing at least one atom selected from a nitrogen atom, an oxygen atom and a sulfur atom in which an 8-membered ring is fused, and more specifically pyridine Ring, pyrazine ring, pyrimidine ring, 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, Examples include a furan ring, a thiazole ring, an oxazole ring, an indole ring, an isoindole ring, an indazole ring, a benzimidazole ring, a benzotriazole ring, a benzothiazole ring, a benzoxazole ring, a purine ring, and a carbazole ring.

Examples of the alicyclic heterocyclic ring include a nitrogen atom,
A 5- or 6-membered monocyclic alicyclic heterocyclic ring containing at least one atom selected from an oxygen atom and a sulfur atom;
A bicyclic or tricyclic fused 8-membered ring and a condensed alicyclic heterocyclic ring containing at least one atom selected from a nitrogen atom, an oxygen atom and a sulfur atom, and the like, and more specifically, Pyrrolidine ring, piperidine ring, piperazine ring, morpholine ring, thiomorpholine ring, homopiperidine ring, homopiperazine ring, tetrahydropyridine ring, tetrahydroquinoline ring, tetrahydroisoquinoline ring, tetrahydrofuran ring, tetrahydropyran ring, dihydrobenzofuran ring, tetrahydrocarbazole ring And the like.

A heterocyclic ring formed by R ₁ and R ₂ , or R ₄ and R ₅ together with an adjacent nitrogen atom, and an N—C— group formed by R ₄ and R ₆ , or R ₅ and R ₇ are adjacent to each other.
Examples of the nitrogen-containing heterocycle formed together with C include an aromatic heterocycle containing a nitrogen atom and an alicyclic heterocycle containing a nitrogen atom.

The aromatic heterocycle containing a nitrogen atom is, for example, a 5- or 6-membered monocyclic aromatic heterocycle containing at least one nitrogen atom, a bicyclic or tricyclic fused 3- to 8-membered ring. And a condensed aromatic heterocyclic ring containing at least one nitrogen atom, more specifically, a pyridine ring, a pyrazine ring, a pyrimidine ring, a pyridazine ring, a quinoline ring, an isoquinoline ring, a phthalazine ring, and a quinazoline ring. , Quinoxaline ring, naphthyridine ring, cinnoline ring, pyrrole ring,
Pyrazole ring, imidazole ring, triazole ring, tetrazole ring, thiazole ring, oxazole ring, indole ring, isoindole ring, indazole ring, benzimidazole ring, benzotriazole ring, benzothiazole ring, benzoxazole ring, purine ring, carbazole ring, etc. Is mentioned.

The alicyclic heterocyclic ring containing a nitrogen atom is, for example, a 5- or 6-membered monocyclic alicyclic heterocyclic ring containing at least one nitrogen atom, a bicyclic ring in which a 3- to 8-membered ring is fused or Tricyclic and alicyclic alicyclic heterocycles containing at least one nitrogen atom and the like, and more specifically, a pyrrolidine ring, a piperidine ring, a piperazine ring, a morpholine ring, a thiomorpholine ring, a homopiperidine ring, Examples include a piperazine ring, a tetrahydropyridine ring, a tetrahydroquinoline ring, a tetrahydroisoquinoline ring, and a tetrahydrocarbazole ring.

The alicyclic hydrocarbon ring formed by R ₁₃ and R ₁₄ or R ₁₇ and R ₁₈ together with adjacent (two) carbon atoms includes those having 3 to 8 carbon atoms. It may be saturated or unsaturated, for example,
Examples include a cyclopropane ring, a cyclobutane ring, a cyclopentane ring, a cyclohexane ring, a cycloheptane ring, a cyclooctane ring, a cyclopentene ring, a 1,3-cyclopentadiene ring, a cyclohexene ring, and a cyclohexadiene ring.

An aromatic ring formed by R ₁₃ and R ₁₄ together with two adjacent carbon atoms, and an aromatic ring formed by two R ₂₀ adjacent to each other with two adjacent carbon atoms Examples of the ring include those having 6 to 14 carbon atoms, such as a benzene ring, a naphthalene ring, and an anthracene ring.

The substituents of the aryl group, aralkyl group, heterocyclic group, aromatic ring, heterocyclic ring containing a nitrogen atom or heterocyclic rings may be the same or different and have 1 to 1 substituent, preferably 1 to 5 substituents. Groups such as hydroxyl, carboxyl, nitro, alkoxy, alkyl, aralkyl, cyano, halogen, -N = N-Ar (Ar
Represents a hydroxyl group, a carboxyl group, a nitro group, an alkoxy group, an alkyl group optionally substituted with a halogen atom, or an aryl group optionally substituted with a substituent such as a cyano group or a halogen atom. ), -CH
= CH-Ar (Ar has the same meaning as described above). Examples of the alkyl group, alkoxy group, aralkyl group, aryl group, and halogen atom include the same as those described above.

The substituents of the alkyl group or the alkoxy group may be the same or different and have 1 to 1 substituent, preferably 1 to 3 substituents, for example, a hydroxyl group, a carboxyl group, a nitro group, an alkoxy group, an aryl group, And a halogen atom. Examples of the alkoxy group, the aryl group, and the halogen atom include the same as described above.

Examples of the substituent of the amino group include the same or different and one or two substituents such as an alkyl group and an aryl group. Examples of the alkyl group and the aryl group include the same as those described above.

Next, the method for producing the squarylium compound used in the present invention will be described with reference to the compounds represented by formulas (III) and (VI) as examples. Where the general formula (II
Compounds represented by (I) and (VI) were each converted to compound (I
II) and compound (VI). The same applies to compounds of other formula numbers.

Reaction formula (1-a)

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Reaction formula (1-b)

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Reaction formula (1-c)

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Reaction formula (2-a)

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Reaction formula (2-b)

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Reaction formula (2-c)

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In the above reaction formula, R ₁ , R ₂ and R ₃ are as defined above, and Y is a halogen atom such as chlorine or bromine or OR ₂₁ (where R ₂₁ represents an alkyl group.
_As the alkyl group in the definition of ₂₁ , the general formula (III)
The same as the specific examples of the alkyl group in (VI) to (VI) can be mentioned. ).

In the above reaction formula (1-a), compound (C) is obtained by combining compound (A) with 0.4 to 2 moles of compound (B), if necessary, at 0.4 to 2 moles. In the presence of a base,
It is obtained by reacting in a solvent at room temperature to the boiling point of the solvent for 1 to 4 hours. Examples of the solvent include chloroform, dichloromethane, 1,2-dichloroethane, ethyl acetate, diethyl ether, methyl-tert-butyl ether, tetrahydrofuran, toluene, benzene, dimethylformamide, dimethyl sulfoxide and the like. Examples of the base include organic bases such as quinoline, triethylamine and pyridine, and inorganic bases such as potassium hydrogen carbonate and sodium hydrogen carbonate.

In the above reaction formula (1-b), the compound (D) is prepared by converting the compound (C) into a 50-90% by volume / wt. Aqueous acetic acid solution at 90-110 ° C. for 1-7 hours, or It is obtained by treating in a 99% by weight aqueous solution of trifluoroacetic acid or concentrated sulfuric acid at 40 to 60 ° C for 1 to 3 hours.

In the above reaction formula (1-c), compound (III) is obtained by combining compound (D) with 0.5 to 2 moles of compound (E), if necessary, 1.0 to 2.0 times. It is obtained by reacting in a solvent at 80 to 120 ° C. for 1 to 15 hours in the presence of a molar base. As the solvent, for example, ethanol, propanol, isopropanol, butanol,
Only an alcohol solvent having 2 to 8 carbon atoms such as octanol or a mixed solvent of the alcohol solvent and benzene or toluene (50 vol / vol% or more of alcohol)
Are used. As the base, for example, an organic base such as quinoline, triethylamine and pyridine or an inorganic base such as potassium carbonate, potassium hydrogen carbonate and sodium hydrogen carbonate is used.

In the above reaction formula (2-a), the same operation as in the above reaction formula (1-a) is performed, except that the compound (F) is replaced with the compound (E) instead of the compound (B). Can be obtained by:

In the above reaction formula (2-b), the same operation as in the above reaction formula (1-b) is carried out except that the compound (G) is replaced with the compound (F) instead of the compound (C). Can be obtained by:

In the above reaction formula (2-c), compound (III) is obtained by replacing compound (D) with compound (G).
Except that the compound (B) is used instead of the compound (E),
It can be obtained by performing the same operation as in the above reaction formula (1-c).

After the reaction, the compound (III) is, for example, subjected to solvent distillation or filtration and, if necessary, further purified by a method usually used in organic synthetic chemistry (column chromatography, recrystallization or washing with a solvent, etc.). It is isolated and purified by the treatment.

Reaction formula (3-a)

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Reaction formula (3-b)

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Reaction formula (3-c)

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Reaction formula (4-a)

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Reaction formula (4-b)

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Reaction formula (4-c) Compound (P) + Compound (Ha) or Compound (Hb)
→ Compound (VI)

In the above reaction formula, Q ₂ , R ₁₅ , R ₁₆ , R ₁₇ ,
R ₁₈ , R ₁₉ , R ₂₀ and n have the same meanings as described above, X represents a halogen atom such as chlorine, bromine or iodine, or a tosyl group or a mesyl group, and Y has the same meaning as described above.

In the above reaction formula (3-a), the compound (J) is the same as the compound (A) in the amount of the compound (H
It can be obtained by reacting a) or (Hb) in a solvent at 0 ° C. to room temperature for 30 minutes to 70 hours, if necessary, in the presence of 1 to 2 moles of a base. Examples of the solvent include chloroform, dichloromethane, 1,2-dichloroethane, ethyl acetate, diethyl ether, methyl-tert-butyl ether, tetrahydrofuran, toluene, benzene, dimethylformamide, dimethyl sulfoxide and the like. Examples of the base include organic bases such as quinoline, triethylamine and pyridine, and inorganic bases such as potassium hydrogen carbonate and sodium hydrogen carbonate.

In the above reaction formula (3-b), compound (K) is prepared by converting compound (J) into a 50-90 vol / vol% aqueous acetic acid solution at 90-110 ° C. for 1-7 hours, or 50-90 vol. In a 99% by weight aqueous trifluoroacetic acid solution, 45
It is obtained by treating at 〜50 ° C. for 1 to 3 hours.

In the above reaction formula (3-c), compound (VI) is obtained by converting compound (K) with 0.5 to 2 moles of compound (L), if necessary, It is obtained by reacting in a solvent at 80 to 120 ° C. for 1 to 15 hours in the presence of a molar base. As the solvent, for example, ethanol, propanol, isopropanol, butanol,
Only an alcohol solvent having 2 to 8 carbon atoms, such as octanol, or a mixed solvent of the alcohol solvent and benzene or toluene (50 vol / vol% or more of alcohol)
Are used. As the base, for example, an organic base such as quinoline, triethylamine and pyridine or an inorganic base such as potassium carbonate, potassium hydrogen carbonate and sodium hydrogen carbonate is used.

In the reaction formula (4-a), the compound (M) is the same as the reaction formula (3-a) except that the compound (L) is used instead of the compound (Ha) or (Hb). Can be obtained by performing the following operations.

In the above reaction formula (4-b), the same operation as in the above reaction formula (3-b) is performed, except that the compound (P) is replaced with the compound (M) instead of the compound (J). Can be obtained by:

In the above reaction formula (4-c), compound (VI) is compound (P) instead of compound (K), and compound (Ha) or compound (H) is used instead of compound (L).
Except for using b), it can be obtained by performing the same operation as in the aforementioned reaction formula (3-c).

After the reaction, the compound (VI) is purified, for example, by distilling off the solvent or by filtration, if necessary, by a method usually used in organic synthetic chemistry (column chromatography, recrystallization or washing with a solvent, etc.). It is isolated and purified by the treatment.

Next, physical properties required for the recording layer of the optical recording medium of the present invention 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 the thermal characteristics, 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 a reproduction stability of 1,000,000 times or more of repetition and a 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 diagram 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 the substrate material, for example, polyester,
Acrylic resin, polyamide, polycarbonate resin, polyolefin resin, phenol resin, epoxy resin, plastic such as 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, and address signals are provided. Etc. may be formed.

(Recording Layer) The recording layer is capable of recording information by a certain optical change upon irradiation with a laser beam, and the change in the recording layer contains a dye mixture (squarylium) characteristic of the present invention. (A mixture of a compound and a formazan metal chelate compound), and the dye mixture characteristic of the present invention may be used singly or in combination of two or more in forming the recording layer. 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, croconium dyes, pyrylium dyes, naphthoquinone dyes, and the like.
Anthraquinone (indanthrene), xanthene,
Triphenylmethane, azulene, tetrahydrocholine, phenanthrene, triphenothiazine 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, a polymer material such as an ionomer resin in the dye mixture,
Various materials such as polyamide-based resins, vinyl-based resins, natural polymers, silicones, liquid rubbers, or silane coupling agents may be dispersed and used, or stabilizers (such as transition metals Complex), dispersant,
Flame retardants, lubricants, antistatic agents, surfactants, plasticizers and the like can be used together.

Specific examples of the formazan metal chelate compound used in the present invention are shown in Tables 1 to 3 below. In Tables 1 to 3, Me represents a methyl group, nBu represents n-butyl, and Ph represents phenyl.

[Table 1]

[Table 2]

[Table 3]

Specific examples of the squarylium compound used in the present invention are shown in Tables 4 to 6 below. In Tables 4 to 6, nPr represents n-propyl, iPr represents isopropyl, and Ph represents phenyl.

[Table 4]

[Table 5]

[Table 6]

The recording layer was 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 °.

(Undercoating layer) The undercoating 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 of (e) and (f), an ultraviolet curable resin, a thermosetting resin, a thermoplastic resin, or the like is used. 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 that 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 metal reflective layer include vapor deposition and sputtering.
000 °, more preferably 100-3000 °.

(Protective Layer, Hard Coat Layer on Substrate Surface) The protective layer or 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. 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 preferred example of the protective layer or the substrate surface hard coat layer among the above materials is an ultraviolet curable resin having excellent productivity.

The thickness of the protective layer or the hard coat layer on the surface of the substrate 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 in the same manner as in 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 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. From the viewpoint of productivity, an ultraviolet-curable or hot-melt adhesive is preferable.

[0143]

The present invention will be described more specifically below with reference to examples and comparative examples. Table 7 below shows the evaluation results of the optical recording media obtained in these Examples and Comparative Examples. The compounds used in Examples and Comparative Examples are as shown in Table 1 above.
6 to 6.

Example 1 Compound examples A-5 and B- were formed on a 0.6 mm-thick injection-molded polycarbonate substrate having a guide groove with a groove depth of 1750 °, a half width of 0.25 μm and a track pitch of 0.74 μm. 3 (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 dye mixtures having the combinations shown in Table 7.

(Comparative Example 1) A recording medium was formed in exactly the same manner as in Example 1 except that only the squarylium compound B-2 was used.

<Recording Conditions> An EFM signal (linear velocity: 3.5 m
/ S) was recorded and reproduced with continuous light (reproduction power 0.7 mW) of a semiconductor laser having an oscillation wavelength of 658 nm, and a reproduction waveform was observed. <Weather resistance test conditions> Light resistance test: 40,000 Lux, Xe light, 10 hours continuous irradiation Storage test: 50 ° C., 80% RH, left for 800 hours

(Evaluation results)

[Table 7]

[0149]

According to the present invention, it is possible to provide an optical recording medium capable of recording and reproducing with a laser beam in a wavelength range of 600 to 720 nm, and having excellent light resistance and storage stability. In particular, it has become possible to provide an optical recording medium having excellent light fastness as compared with one using a squarylium compound alone. 2) Claims 5 to 6 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 7 In addition to the first effect, an optical recording medium capable of performing stable recording and reproduction can be provided. 4) Claim 9 A novel optical recording method capable of achieving the effect of the optical recording medium can be provided. 5) Claim 10 A novel optical recording device capable of achieving the effect of the optical recording medium can be provided.

[Brief description of the drawings]

FIGS. 1A to 1D are schematic views showing the configuration of a write-once optical recording medium to which the optical recording medium of the present invention can be applied.

FIGS. 2A to 2C are diagrams illustrating the configuration of a CD-R optical recording medium to which the optical recording medium of the present invention can be applied.

FIGS. 3A to 3C are diagrams illustrating the configuration of a DVD-R optical recording medium to which the optical recording medium of the present invention can be applied.

[Explanation of symbols]

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

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI theme coat ゛ (Reference) G11B 7/24 516 G11B 7/24 522A 522 538E 538 561N 561 B41M 5/26 Y (72) Inventor Mune Noguchi Ricoh Co., Ltd. 1-3-6 Nakamagome, Ota-ku, Tokyo (72) Inventor Tsutomu Tsutomu 1-3-6 Nakamagome, Ota-ku, Tokyo Ricoh Co., Ltd. (72) Tatsuya Tomura Ota-ku, Tokyo 1-3-6 Nakamagome, Ricoh Co., Ltd. (72) Inventor Yasunobu Ueno 1-3-6 Nakamagome, Ota-ku, Tokyo Co., Ltd. Ricoh Co., Ltd. 3-chome Kyowa Yuka Co., Ltd. Yokkaichi Research Laboratory (72) Inventor Motoharu Kinugasa 2-3-3 Daikyocho, Yokkaichi-shi, Mie In Kyowa Yuka Co., Ltd. Yokkaichi Research Laboratory (72) Inventor Hiroshi Toyoda 2-3 cho, Okamachi, Yokkaichi City, Mie Prefecture Kyowa Yuka Co., Ltd. No. 3 F-term in Yokkaichi R & D Co., Ltd. Kyowa Yuka Co., Ltd. (Reference) 2H111 EA03 EA12 EA22 EA39 EA40 FA01 FA12 FA23 FA31 FB30 FB42 FB48 4H056 CA01 CC02 CC08 CE01 CE03 CE06 CE07 DD03 DD06 EA05 EA13 FA01 5D029 JA04 JC01 MA05

Claims (10)

[Claims] An optical recording medium comprising a recording layer provided on a substrate, a squarylium compound, a formazan compound represented by the following general formula (I) and / or a general formula (II) in the recording layer, and a metal. And an at least one formazan metal chelate compound comprising: 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 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 or an aryl group which may have a substituent. ] [Wherein, Z ₁ and Z ₂ each represent a residue forming a substituted or unsubstituted 5- or 6-membered nitrogen-containing heterocyclic ring containing a nitrogen atom. Another aromatic ring may be condensed with the nitrogen-containing heterocyclic ring. A ₁ and A ₂ are an alkyl group optionally having a substituent, an aryl group optionally having a substituent, an alkylcarbonyl group optionally having a substituent,
An arylcarbonyl group which may have a substituent, an alkenyl group which may have a substituent, a heterocyclic residue which may have a substituent, or an alkoxy which may have a substituent Represents a carbonyl group. 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 -
Or -SO ₂ - represents a. m is an integer of 0 or 1. ] 2. The optical recording medium according to claim 1, wherein the weight ratio of the squarylium compound to the formazan metal chelate compound is 90:10 to 50:50. 3. The method according to claim 1, wherein the metal atom of the formazan metal chelate compound is vanadium, manganese, iron, cobalt, nickel,
3. The method according to claim 1, wherein the material is copper, zinc, palladium, or an oxide or halide thereof.
The optical recording medium according to the above. 4. A squarylium compound represented by the following general formula (II)
Be a compound represented by I) and / or (VI)
The optical recording device according to any one of claims 1 to 3, wherein
Recording medium. Embedded image[Wherein, R₁And R_TwoAre the same or different,
A substituent, an alkyl group which may have a substituent,
Which may have an aralkyl group or a substituent
Aryl group or hetero-substituted hetero group
Represents a ring residue. Also, R₁And R_TwoIs the adjacent nitrogen atom
Forms an optionally substituted heterocyclic ring with
May be. R_ThreeRepresents the following general formula (IV) or (V)
Represent: embedded image(Where R_FourAnd R_FiveAre the same or different,
Represents an alkyl group which may have a substituent or a substituent
Or R_FourAnd R_FiveTogether with the adjacent nitrogen atom
Can form a heterocyclic ring which may have a substituent.
Come, R₆, R₇, R₈And R₉Are the same or different
A hydrogen atom, an alkyl group which may have a substituent,
An alkoxy group which may have a substituent, a hydroxyl group, or
Represents a halogen atom;_FourAnd R₆Or R_FiveAnd
And R₇Is a nitrogen-containing compound together with the adjacent NCC.
A nitrogen-containing heterocyclic ring having a substituent.
(May be used)(Where Q₁Represents a carbon atom or a nitrogen atom;_TenYou
And R₁₁Are the same or different and each represents a hydrogen atom or a substituent.
May have an alkyl group, may have a substituent
Aryl groups and aralkyl groups which may have a substituent
Or a hydroxyl group (however, Q₁Is a nitrogen atom,
₁₁Does not exist), and R₁₂Represents a hydrogen atom and a substituent
May have an alkyl group, may have a substituent
Aryl groups or aralkyl which may have a substituent
R₁₃And R₁₄Are the same or different, water
Elemental atom, alkyl group which may have a substituent, substituent
An alkoxy group or a halogen atom which may have
Represents or R₁₃And R ₁₄Are two adjacent carbon sources
Together with an alicyclic hydrocarbon ring, having a substituent
An aromatic ring or a compound which may have a substituent;
It may form a ring. )][Where Q_TwoRepresents a carbon atom or a nitrogen atom;
₁₅Is a hydrogen atom or an optionally substituted alkyl
Group, aryl group which may have a substituent or substituent
Represents a heterocyclic group optionally having₁₆Is a hydrogen atom,
A halogen atom, an alkyl group which may have a substituent,
An alkoxy group which may have a substituent,
Optionally having an aralkyl group, may have a substituent
An aryl group, an amino group which may have a substituent or
Represents a heterocyclic group which may have a substituent. R₁₇and
R₁₈Are the same or different and may have a substituent
Represents a good alkyl group or R₁₇And R₁₈Is the adjacent carbon source
Having an alicyclic hydrocarbon ring or a substituent together with the
May form an optionally substituted heterocyclic ring. However, Q_TwoBut
In the case of a nitrogen atom, R₁₈Does not exist. R₁₉Is a hydrogen atom,
An alkyl group which may have a substituent,
Optionally having an aralkyl group or a substituent
Represents an aryl group;₂₀Has a halogen atom and a substituent
May have an alkyl group or a substituent
An aralkyl group, an aryl group which may have a substituent,
Trifluoromethyl, nitro, cyano, or
Represents an alkoxy group which may have a substituent. n is 0
Represents an integer of 4, where n is 2 to 4;₂₀Is the same
May be one or different, and are next to each other
Two R ₂₀Together with two adjacent carbon atoms
May form an aromatic ring which may have a substituent
No. ] 5. The recording layer single layer has a refractive index n of 1.5 ≦ n ≦ 3.0 and a extinction coefficient k of 0.02 ≦ k ≦ 0 for light in a wavelength range of ± 5 nm. The optical recording medium according to claim 1, wherein the number is 3. 6. A reflective layer, wherein the reflective layer is made of gold, silver,
The optical recording medium according to any one of claims 1 to 5, comprising copper, aluminum, or an alloy of these metals. 7. The track pitch on a substrate is 0.7-0.
8 μm, and the groove width is half width, 0.18 to 0.40 μm.
The optical recording medium according to claim 1, wherein m is m. 8. The optical recording medium according to claim 1, wherein recording is possible at a recording wavelength of 600 to 720 nm. 9. An optical recording method comprising recording on the optical recording medium according to claim 1 at a recording wavelength of 600 to 720 nm. 10. An optical recording apparatus comprising the optical recording medium according to claim 1.