JP2002274044A - Optical recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a recording material in an optical recording medium which is adoptable to a DVD-R disk system using a semiconductor laser having the oscillating wavelength in a shorter wavelength compared with a conventional system, and is excellent in light-resistance and preservation stability especially in a conventional optical recording medium using a trimethine cyanin coloring matter. SOLUTION: For this optical recording medium, a recording layer is provided on a substrate. In such an optical recording medium, an azo metal chelate compound comprising the trimethine cyanin coloring matter and an azo compound represented by general formula (I), is contained by a weight ratio of 90:10 to 10:90 for the percentage of the trimethine cyanin coloring matter : the azo metal chelate compound. In general formula (I), R1 and R2 each represent a substituent which is directly bonded with a triazine ring. R3 to R6 each represent a substituent which is directly bonded with a benzene ring (another aromatic ring may be condensed in the benzene ring). Z represents a substituent having an active hydrogen group.

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, and is applied to a large-capacity optical card and the like.

[0002]

2. Description of the Related Art (for information recording) write-once recording media (WOR)
As the prior art M), those using a cyanine dye as a recording material are disclosed in JP-A-57-82093, JP-A-58-56892, and JP-A-58-112790.
JP, JP-A-58-114989 and JP-A-59-149899
-85791, JP-A-60-83236,
JP-A-60-89842, JP-A-61-2588
No. 6,150,243, which uses a phthalocyanine dye as a recording material.
JP, JP-A-61-177287, JP-A-61-177287
JP-A-154888, JP-A-61-24609, JP-A-62-39286, JP-A-63-37
No. 991, JP-A-63-39888 and the like.

Further, a write-once compact disc (CD-
As the prior art of R), those using a cyanine dye + metal reflective layer as a recording material are disclosed in JP-A-1-159842, JP-A-2-42652, and JP-A-2-136.
No. 56, JP-A-2-168446, etc., which use a phthalocyanine dye + metal reflective layer as a recording material are disclosed in JP-A-1-176585, JP-A-3-215466, Kaihei 4-113886
JP, JP-A-4-226390, JP-A-5-1
272, JP-A-5-171052, JP-A-5-116456, JP-A-5-96860, JP-A-5-139944, JP-A-5-139
No. 044, which uses an azo metal chelate dye and a metal reflective layer as a recording material,
-46186, JP-A-4-141489,
JP-A-4-36088, JP-A-5-27958
0, JP-A-7-51673, and JP-A-7-1
These are disclosed in JP-A-61069, JP-A-7-37272, JP-A-7-71867, JP-A-8-231866, JP-A-8-295811 and the like.

Further, as a prior art of a large capacity write-once compact disc (DVD-R), a technique using a cyanine dye + metal reflective layer as a recording material is known as PIONEER R & D.
vol.6No.2: Development of DVD-Recordable, Basic development of DVD-R dye disk, ISOM / ODS'96: High density
of recording on Dye material Disc approach for4.7
G, JP-A-10-235999 and the like, and those using an azomethine dye + metal reflective layer as a recording material are disclosed in JP-A-8-198872 and JP-A-8-209.
No. 012, JP-A-8-283263, JP-A-10-273484, etc., which use an azo metal chelate dye + metal reflective layer as a recording material are disclosed in Japanese Patent Publication No. 5-67438. JP-A-7-1610
No. 69, JP-A-8-156408, JP-A-8-156408
JP-A-231866, JP-A-8-332772, JP-A-9-58123, JP-A-9-1750
No. 31, JP-A-9-193545, JP-A-9-193545
-274732, JP-A-9-277703, JP-A-10-6644, JP-A-10-665
0, JP-A-10-6651, JP-A-10-65
JP-A-369693, JP-A-10-44606, JP-A-10-58828, and JP-A-10-86519.
JP, JP-A-10-149584, JP-A-10-149584
-157293, JP-A-10-157300, JP-A-10-157301, JP-A-10-1
No. 57302, JP-A-10-181199,
JP-A-10-181201, JP-A-10-181
No. 203, JP-A-10-181206, JP-A-10-188340, JP-A-10-18834
No. 1, JP-A-10-188358, JP-A-10-188358
JP-A-208303, JP-A-10-214423, JP-A-10-228671, JP-A-10-208
Japanese Patent Application Laid-Open Nos. 10-86517 and 10-93788 disclose other dyes and a metal reflective layer as a recording material. JP-A-10-22617
No. 2, Japanese Unexamined Patent Application Publication No. 10-244752, Japanese Unexamined Patent Application Publication No.
JP-A-287819, JP-A-10-297103, JP-A-10-309871, JP-A-10-
Japanese Patent Application Publication No. Hei 7-51682 and Japanese Patent Application Laid-Open No. 11-51682 disclose a recording medium using a cyanine dye + azo metal chelate dye + metal reflective layer as a recording material.
No. 34499/34.

At present, as a next-generation large-capacity optical disk, DV
Development of DR is in progress. Development of recording materials for miniaturization of recording pits,
It is necessary to develop technology such as adoption of an image compression technology represented by PEG2 and shortening of the wavelength of a semiconductor laser for reading recording pits.

Heretofore, as a semiconductor laser in the red wavelength region, a 670 nm band Al for a bar code reader and a measuring instrument has been used.
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 630 nm band to 670 nm
It is standardized by the wavelength of the laser diode in the band. On the other hand, a DVD-ROM drive for reproduction only has a wavelength of 650 to 650.
Commercialized in nm.

[0007] Under these circumstances, the most preferable DVD-
The R media is a medium that can record and reproduce at a wavelength of 630 to 670 nm. However, a recording material which is excellent in light resistance and storage stability and which can be recorded and reproduced by an optical pickup using a laser of 670 nm or less has not yet been developed.

[0008] One of the recording layers of an optical recording medium for recording and reproducing with an optical pickup using a laser having a wavelength of 630 to 670 nm is a trimethine cyanine dye, but this dye is remarkably deteriorated by light and has poor stability. In addition, an azo metal chelate dye is exemplified as a dye exhibiting high light resistance. However, a medium using this dye in a recording layer has a problem such as low reflectance.

[0009]

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 a conventional system. It is an object of the present invention to provide a recording material having excellent light resistance and storage stability in an optical recording medium using a trimethine cyanine dye.

[0010]

Means for Solving the Problems As a result of intensive studies, the present inventors have found that a recording layer having a mixture of a dye having a specific structure as a main component has an oscillation wavelength of 670 nm.
The present invention has been found to be able to provide an optical recording medium which is applicable to a next-generation large-capacity optical disk system using the following semiconductor laser and has excellent light resistance and storage stability.

[0011] The object of the present invention is to provide (1) an optical recording medium comprising a recording layer provided on a substrate, wherein a trimethine cyanine dye and an azo compound represented by the following general formula (I) are contained in the recording medium. And an azo metal chelate compound comprising a metal and a trimethine cyanine dye: azo metal chelate compound in a weight ratio of 90:10 to 10:90.

[0012]

Embedded image In the general formula (I), R ₁ and R ₂ represent a substituent directly bonded to a triazine ring, and R _{3 to} R ₆ are directly bonded to a benzene ring (another aromatic ring may be condensed to the benzene ring). Z represents a bonded substituent, and Z represents a substituent having an active hydrogen group. Here, R ₁ and R ₂ each independently represent a hydrogen atom, a halogen atom, a nitro group, a cyano group, a hydroxyl group, a carboxyl group, an amino group, a carbamoyl group, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group. Group, substituted or unsubstituted heterocyclic residue, substituted or unsubstituted alkyloxy group, substituted or unsubstituted aryloxy group, substituted or unsubstituted alkylthio group, substituted or unsubstituted arylthio group, substituted or unsubstituted Alkylamino group, substituted or unsubstituted arylamino group, substituted or unsubstituted alkyloxycarbonyl group, substituted or unsubstituted aryloxycarbonyl group, substituted or unsubstituted alkylcarboxamide group, substituted or unsubstituted arylcarboxamide Group,
Represents a substituted or unsubstituted alkylcarbamoyl group, a substituted or unsubstituted arylcarbamoyl group, or a substituted or unsubstituted alkenyl group. R _{3 to} R ₆ are selected from the above-mentioned R ₁ and R ₂ substituents. The substituent having an active hydrogen group of Z is a hydroxyl group, a carboxyl group, an amino group, an alkylcarboxamide group, an arylcarboxamide group, an alkylsulfonamide group, an arylsulfonamide group, a carbamoyl group, an alkylcarbamoyl group,
Represents an arylcarbamoyl group, a sulfo group, a sulfino group, a sulfeno group, or a sulfamoyl group "(2)" the metal atom of the azo metal chelate compound is selected from manganese, cobalt, nickel, and copper; (1) The optical recording medium according to the above (1), wherein the trimethine cyanine dye has a structure represented by the following general formula (II). Medium.

[0013]

Embedded image In the formula (II), R ₇ and R ₈ each represent a substituent directly bonded to a nitrogen atom, Y represents a substituent directly bonded to a benzene ring, and X ⁻ represents a monovalent anion. Here, R ₇ and R ₈ are a substituted or unsubstituted alkyl group. Y is a hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted alkyloxy group. And (4) "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, the optical recording medium according to any one of the above items (1) to (3), ” (5) Any one of the above items (1) to (4), wherein the reflective layer having a reflective layer is made of gold, silver, copper, aluminum, or an alloy of these metals. Optical recording medium according to
(6) "The track pitch on the substrate is 0.7 to 0.8.
The optical recording medium according to any one of the above items (1) to (5), wherein the groove width is 0.18 to 0.40 [mu] m in half width. "Recording wavelength is 6
(1) characterized in that the thickness is from 00 to 720 nm.
The optical recording medium according to any one of the items (6) to (6) ". Specific examples of the monovalent anion X of the trimethine cyanine dye represented by the general formula (II) in the optical recording medium described in the above item (3) include I ⁻ , ClO ₄ ⁻ , BF ₄ ⁻ ,
PF ₆ ⁻ , SbF ₆ ⁻ , p-toluenesulfonic acid ion and the like.

The effects of each item are described below. Item (1) shows the basic structure of an optical recording medium using a mixture of a cyanine dye and an azo metal chelate compound of the present invention. And (2) is the limitation of the optimum metal species of the azo metal chelate dye in (1);
The item (3) is a limitation on the optimum structure of the cyanine dye in the item (1). The item (4) is for limiting the optical characteristics of the dye mixture which can be recorded and reproduced with a high reflectance and a high degree of modulation, and the item (5) is for limiting the optimum reflection layer conditions for high density media to be applied. The item (6) is a limitation on the optimum substrate guide groove condition for high density media to be applied, and the item (7) is a limitation on a recording wavelength for high density media to be applied.

The optical recording medium of the present invention is characterized in that a trimethine cyanine dye, an azo compound represented by the above general formula (I) and an azo metal chelate compound comprising a metal are contained in a recording layer in a weight ratio of the trimethine cyanine dye: 90:10 to 10:90, preferably 80:20 to 4 for the azo metal chelate compound
It is characterized in that it is contained at a ratio of 0:60.

By adding the azo metal chelate compound at such a ratio to the trimethine cyanine dye, the photodegradation of the trimethine cyanine dye is prevented, and an optical recording medium having excellent light resistance is obtained. On the other hand, if the amount of the trimethine cyanine dye exceeds the above range, the effect of the azo metal chelate compound is reduced, and sufficient light resistance cannot be obtained. On the other hand, when the amount of the trimethine cyanine dye is less than the above range, there are problems such as a decrease in reflectance.

In the above formula (I), R ₁ and R ₂ represent a substituent directly bonded to a triazine ring, and R _{3 to} R ₆ represent a benzene ring (even if another aromatic ring is condensed to the benzene ring). And Z represents a substituent having an active hydrogen group. Here, R ₁ and R ₂ each independently represent a hydrogen atom, a halogen atom, a nitro group, a cyano group, a hydroxyl group, a carboxyl group, an amino group, a carbamoyl group, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group. Group, substituted or unsubstituted heterocyclic residue,
Substituted or unsubstituted alkyloxy group, substituted or unsubstituted aryloxy group, substituted or unsubstituted alkylthio group, substituted or unsubstituted arylthio group, substituted or unsubstituted alkylamino group, substituted or unsubstituted arylamino Group, substituted or unsubstituted alkyloxycarbonyl group, substituted or unsubstituted aryloxycarbonyl group, substituted or unsubstituted alkylcarboxamide group, substituted or unsubstituted arylcarboxamide group, substituted or unsubstituted alkylcarbamoyl group, substituted Or an unsubstituted arylcarbamoyl group,
Represents a substituted or unsubstituted alkenyl group.

Specific examples of the substituted or unsubstituted alkyl group include a methyl group, an ethyl group, an n-propyl group,
n-butyl group, n-pentyl group, n-hexyl group, n-
Primary alkyl groups such as heptyl group, n-octyl group, n-nonyl group, n-decyl group, isobutyl group, isoamyl group, 2-methylbutyl group, 2-methylpentyl group, 3-
Methylpentyl, 4-methylpentyl, 2-ethylbutyl, 2-methylhexyl, 3-methylhexyl, 4-methylhexyl, 5-methylhexyl, 2
-Ethylpentyl group, 3-ethylpentyl group, 2-methylheptyl group, 3-methylheptyl group, 4-methylheptyl group, 5-methylheptyl group, 2-ethylhexyl group, 3-ethylhexyl group, isopropyl group, sec-
Butyl group, 1-ethylpropyl group, 1-methylbutyl group, 1,2-dimethylpropyl group, 1-methylheptyl group, 1-ethylbutyl group, 1,3-dimethylbutyl group,
1,2-dimethylbutyl group, 1-ethyl-2-methylpropyl group, 1-methylhexyl group, 1-ethylheptyl group, 1-propylbutyl group, 1-isopropyl-2-methylpropyl group, 1-ethyl- 2-methylbutyl group, 1
-Ethyl-2-methylbutyl group, 1-propyl-2-methylpropyl group, 1-methylheptyl group, 1-ethylhexyl group, 1-propylpentyl group, 1-isopropylpentyl group, 1-isopropyl-2-methylbutyl group,
1-isopropyl-3-methylbutyl group, 1-methyloctyl group, 1-ethylheptyl group, 1-propylhexyl group, secondary alkyl groups such as 1-isobutyl-3-methylbutyl group, neopentyl group, tert-butyl group, te
tertiary alkyl groups such as rt-hexyl group, tert-amyl group and tert-octyl group; cyclohexyl group;
Methylcyclohexyl group, 4-ethylcyclohexyl group, 4-tert-butylcyclohexyl group, 4- (2
-Ethylhexyl) cycloalkyl group such as cyclohexyl group, bornyl group and isobornyl group (adamantyl group).

Furthermore, these primary and secondary alkyl groups are
Hydroxyl group, halogen atom, nitro group, carboxyl group, cyano group, substituted or unsubstituted aryl group, may be substituted with a substituted or unsubstituted heterocyclic residue,
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 methoxymethyl, methoxyethyl, ethoxymethyl, ethoxyethyl, butoxyethyl, ethoxyethoxyethyl, phenoxyethyl, methoxypropyl, and ethoxy. Propyl group, piperidino group, morpholino group, and the like.Examples of the alkyl group substituted via sulfur include a methylthioethyl group, an ethylthioethyl group, an ethylthiopropyl group, a phenylthioethyl group, and the like. Examples of the alkyl group substituted through include a dimethylaminoethyl group, a diethylaminoethyl group, and a diethylaminopropyl group.

Specific examples of the substituted or unsubstituted aryl group include a phenyl group, a naphthyl group, an anthranyl group, a fluorenyl group, a phenalenyl group, a phenanthranyl group, a triphenylenyl group, a pyrenyl group and the like. Further, these aryl groups may be substituted with a hydroxyl group, a halogen atom, a nitro group, a carboxyl group, a cyano group, a substituted or unsubstituted aryl group, a substituted or unsubstituted heterocyclic residue, etc. The alkyl group may be substituted via an atom such as sulfur or nitrogen.

Specific examples of the substituted or unsubstituted heterocyclic residue include furyl, thienyl, pyrrolyl, benzofuryl, isobenzofuranyl, benzothienyl, indolinyl, isoindolinyl, carbazolyl, Examples include pyridyl group, piperidyl group, quinolyl group, isoquinolyl group, oxazolyl group, isoxazolyl group, thiazolyl group, isothiazolyl group, imidazolyl group, pyrazolyl group, benzimidazolyl group, pyrazyl group, pyrimidyl group, pyridazinyl group, quinoxalinyl group and the like. Further, these aryl groups may be substituted with a hydroxyl group, a halogen atom, a nitro group, a carboxyl group, a cyano group, a substituted or unsubstituted aryl group, a substituted or unsubstituted heterocyclic residue, etc. The alkyl group may be substituted via an atom such as sulfur or nitrogen.

Specific examples of the halogen atom include fluorine,
Chlorine, bromine, iodine and the like.

The substituted or unsubstituted alkyloxy group may be any one in which a substituted or unsubstituted alkyl group is directly bonded to an oxygen atom. Specific examples of the alkyl group are the same as those described above. Can be mentioned.

The substituted or unsubstituted aryloxy group may be any one in which a substituted or unsubstituted aryl group is directly bonded to an oxygen atom. Specific examples of the aryl group are the same as those described above. Can be mentioned.

The substituted or unsubstituted alkylthio group may be any one in which a substituted or unsubstituted alkyl group is directly bonded to a sulfur atom, and specific examples of the alkyl group are the same as those described above. Things can be mentioned.

The substituted or unsubstituted arylthio group may be any one in which a substituted or unsubstituted aryl group is directly bonded to a sulfur atom, and specific examples of the aryl group are the same as those described above. Things can be mentioned.

The substituted or unsubstituted alkylamino group may be any one in which a substituted or unsubstituted alkyl group is directly bonded to a nitrogen atom. Specific examples of the alkyl group are the same as those described above. Can be mentioned. Further, alkyl groups are bonded to each other, piperidino group, morpholino group, pyrrolidinyl group, piperazinyl group,
A ring may be formed like an indolinyl group and an isoindolinyl group.

The substituted or unsubstituted arylamino group may be any one in which a substituted or unsubstituted aryl group is directly bonded to a nitrogen atom. Specific examples of the aryl group are the same as those described above. Can be mentioned.

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

The substituted or unsubstituted aryloxycarbonyl group may be any one in which a substituted or unsubstituted aryl group is directly bonded to an oxygen atom. Specific examples of the aryl group include those described above. Similar ones can be mentioned.

The substituted or unsubstituted alkylcarboxamide group may be any one in which a substituted or unsubstituted alkyl group is directly bonded to a carbon atom. Specific examples of the alkyl group are the same as those described above. Can be mentioned.

The substituted or unsubstituted arylcarboxamide group may be any one in which a substituted or unsubstituted aryl group is directly bonded to a carbon atom, and specific examples of the aryl group are the same as those described above. Can be mentioned.

The substituted or unsubstituted alkylcarbamoyl group may be any one in which a substituted or unsubstituted alkyl group is directly bonded to a nitrogen atom. Specific examples of the alkyl group are the same as those described above. Can be mentioned. Further, the alkyl groups may be bonded to each other to form a ring like a piperidino group, a morpholino group, a pyrrolidinyl group, a piperazinyl group, an indolinyl group, an isoindolinyl group, and the like.

The substituted or unsubstituted arylcarbamoyl group may be any one in which a substituted or unsubstituted aryl group is directly bonded to a nitrogen atom. Specific examples of the aryl group are the same as those described above. Can be mentioned.

R _{3 to} R ₆ are selected from the above-mentioned R ₁ and R ₂ substituents. The substituent having an active hydrogen group of Z includes a hydroxyl group, a carboxyl group, an amino group, an alkylcarboxamide group, an arylcarboxamide group, an alkylsulfonamide group, an arylsulfonamide group, a carbamoyl group, an alkylcarbamoyl group, an arylcarbamoyl group, and a sulfo group. , A sulfino group, a sulfeno group, and a sulfamoyl group.

Specific examples of the alkylcarboxamide group, arylcarboxamide group, alkylcarbamoyl group and arylcarbamoyl group include the same as those described above.

Specific examples of the alkylsulfonamide group may be those in which a substituted or unsubstituted alkyl group is directly bonded to a sulfur atom, and specific examples of the alkyl group are the same as those described above. Can be mentioned.

Specific examples of the arylsulfonamide group may be those in which a substituted or unsubstituted aryl group is directly bonded to a sulfur atom. Specific examples of the aryl group are the same as those described above. Can be mentioned.

Specific examples of the metal atom include aluminum, titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc, zirconium, niobium, molybdenum, technetium, ruthenium, rhodium, palladium and the like. An azo metal chelate compound of cobalt, nickel, and copper has excellent optical characteristics as an optical recording material.

In the present invention, the recording / reproducing wavelength is set to 600 to 72.
It is characterized by using laser light of 0 nm,
From the optical characteristics at this wavelength, those represented by the above general formula (II) are preferable among the trimethine cyanine dyes. In the general formula (II), R ₇ and R ₈ each represent a substituent directly bonded to a nitrogen atom, Y represents a substituent directly bonded to a benzene ring, and X ⁻ represents a monovalent anion. Here, R ₇ and R ₈ are a substituted or unsubstituted alkyl group. Specific examples of the alkyl group include the same as those described above. Y is a hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted alkyloxy group. Specific examples of the halogen atom include the same as those described above. Specific examples of the alkyl group include the same as those described above. Specific examples of the alkyloxy group include the same as those described above. Specific examples of the monovalent anion of X include I
^{_{-, ClO 4 -, BF 4}} -, PF 6 -, SbF 6 -, p- toluenesulfonate ion and the like.

Next, the configuration of the recording medium will be described.
Items necessary for forming the recording layer include optical characteristics. The conditions required for the optical characteristics are that the recording / reproducing wavelength has a large absorption band on the short wavelength side with respect to the recording / reproducing wavelength of 630 nm to 690 nm, and the recording / reproducing wavelength is near the long wavelength end of the absorption band. is there. This means that it has a large refractive index and an extinction coefficient in the recording / reproducing wavelength of 630 to 690 nm.

Specifically, the refractive index n of the recording layer single layer with respect to light in the wavelength region near the long wavelength near the recording / reproducing wavelength is 1.5 or more and 3.0 or less, and the extinction coefficient k is 0.02 or more. 0.3
It is preferably within the following range. When n is less than 1.5, it is difficult to obtain a sufficient optical change, so that the recording modulation degree becomes low, which is not preferable. When n is more than 3.0, the wavelength dependency becomes too high. Therefore, an error occurs even in the recording / reproducing wavelength region, which is not preferable. When k is less than 0.02, the recording sensitivity deteriorates, which is not preferable. When k exceeds 0.3, it is difficult to obtain a reflectance of 50% or more, which is not preferable.

The conditions required for the substrate shape are that the track pitch on the substrate is 0.7 to 0.8 μm and the groove width is a half width, 0.18 to 0.40 μm, preferably 0.20 to 0.40 μm.
0.36 μm. The substrate usually has a depth of 1000 to 25
It has a guide groove of 00 °. The track pitch is usually 0.7 to 1.0 μm, but is not suitable for high capacity applications.
7 to 0.8 μm is preferred. Groove width is 0.18 in half width
~ 0.40 μm, more preferably 0.20 to
0.36 μm. If it is less than 0.18 μm, it may be difficult to obtain a sufficient tracking error signal intensity. On the other hand, if the thickness exceeds 0.40 μm, the recording portion tends to spread laterally when recording, which is not preferable.

Hereinafter, the optical recording medium of the present invention will be described with reference to the drawings. Configuration of Recording Body The recording body of the present invention is a normal write-once optical disc shown in FIG.
(A so-called air sandwich in which two sheets of FIG. 1 are bonded or a close bonding structure may be used) and FIG.
The media may have a structure of a CD-R medium.

Required Properties of Each Layer and Examples of Constituent Materials The structure of the recording medium of the present invention is basically the structure shown in FIG. Structure. The recording layer may be a single layer of an organic dye layer, or may be a laminate of an organic dye layer and a metal reflective layer to increase the reflectance. 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 / recording layer (organic dye layer) / metal reflective layer / protective layer / adhesive layer / second substrate.

<Substrate> The substrate used in the present invention is required to be transparent to the laser beam used only when recording / reproducing from the substrate side, and when recording / reproducing from the recording layer side, The substrate need not be transparent.
Therefore, in the present invention, when two layers are used, the first substrate may be transparent or opaque as long as only the second substrate is transparent. As a substrate material, for example, a plastic such as polyester, acrylic resin, polyamide, polycarbonate resin, polyolefin resin, phenol resin, epoxy resin, polyimide, glass, ceramic, or metal can be used. When only one substrate is used, or when two substrates are used in a sandwich form, a guide groove and a guide pit for tracking are formed on the surface of the first substrate, and a preformat such as an address signal is formed. Need to be.

<Recording Layer> The recording layer is capable of causing some optical change by irradiation with a laser beam and recording information by the change. The recording layer contains the dye of the present invention. In forming the recording layer, the dye of the present invention may be used alone or in combination of two or more. Further, the dye of the present invention may be used by mixing or laminating with other organic dyes, metals and metal compounds for the purpose of improving optical characteristics, recording sensitivity, signal characteristics and the like. Examples of organic dyes include polymethine dyes, naphthalocyanine-based, phthalocyanine-based, squarylium-based,
Croconium-based, pyrylium-based, naphthoquinone-based, anthraquinone-based (indanthrene-based), xanthene-based, triphenylmethane-based, azulene-based, tetrahydrocholine-based, phenanthrene-based, triphenothiazine-based dyes, metal complex compounds, and the like. The above dyes may be used alone or in combination of two or more.

In the dye, a metal or a metal compound 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 in the dye, for example, an ionomer resin, a polyamide resin, a vinyl resin, a natural polymer, silicone,
Various materials such as liquid rubber, or a silane coupling agent may be dispersed and mixed, or a stabilizer (for example, a transition metal complex), a dispersant, a flame retardant,
It can be used together with a lubricant, an antistatic agent, a surfactant, a plasticizer and the like.

The recording layer can be formed by a usual method such as vapor deposition, sputtering, CVD or solvent coating. When using a coating method, the dye or the like is dissolved in an organic solvent or the like, and the coating is performed by a conventional coating method such as spraying, roller coating, dipping, and spin coating.

As the organic solvent used, generally, alcohols such as methanol, ethanol and isopropanol, ketones such as acetone, methyl ethyl ketone and cyclohexanone, N, N-dimethylformamide,
Amides such as N, N-dimethylacetamide, sulfoxides such as dimethyl sulfoxide, ethers such as tetrahydrofuran, dioxane, diethyl ether, ethylene glycol monomethyl ether, esters such as methyl acetate and ethyl acetate, chloroform, methylene chloride, dichloroethane , Carbon tetrachloride, aliphatic halogenated hydrocarbons such as trichloroethane, benzene, xylene,
Aromatics such as monochlorobenzene and dichlorobenzene,
Examples include cellosolves such as methoxyethanol and ethoxyethanol, and hydrocarbons such as hexane, pentane, cyclohexane, and methylcyclohexane. The thickness of the recording layer is 100 to 10 μm, preferably 200 to 2 μm.
2,000 is appropriate.

<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. , (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), polymer materials such as ionomer resins, polyamide resins, vinyl resins, natural resins, natural polymers, silicones, liquid rubbers, and various other high molecular compounds, and silane cups A ring agent or the like can be used, and for the purposes of (b) and (c),
In addition to the polymer material, an inorganic compound such as SiO, M
gF, SiO ₂ , TiO, ZnO, TiN, SiN and the like, and further, a metal or semimetal such as Zn, Cu, N
i, Cr, Ge, Se, Au, Ag, Al and the like can be used. For the purpose of (d), a metal such as Al, Au, Ag, etc., an organic thin film having metallic luster,
For example, a methine dye, a xanthene dye, or the like can be used. For the purposes (e) and (f), an ultraviolet curable resin, a thermosetting resin, a thermoplastic resin, or the like can be used. The thickness of the undercoat layer is suitably from 0.01 to 30 μm, preferably from 0.05 to 10 μm.

<Metal Reflective Layer> The metal reflective layer may be made of a metal, a semi-metal, or the like which is highly resistant to corrosion and can be obtained by itself. Examples of the material include Au, Ag, Cr, Ni, Al, and F.
e, Sn and the like.
u, Ag, and Al are most preferred. These metals and metalloids may be used alone or as two kinds of alloys. Examples of the film forming method include vapor deposition and sputtering, and the film thickness is 50 to 5000 °, preferably 100 to 30 °.
00 °.

<Protective Layer and Hard Coat Layer on Substrate Surface> The protective layer and the hard coat layer on the substrate surface (a) protect the recording layer (reflection / absorption layer) from scratches, dust, dirt, etc., and (b) the recording layer ( 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. Further, as the inorganic material, SiO, SiO ₂ or the like can be used, and as the organic material, polymethyl acrylate, polycarbonate, epoxy resin, polystyrene,
Heat-softening and heat-melting resins such as polyester resin, vinyl resin, cellulose, aliphatic hydrocarbon resin, natural rubber, styrene butadiene resin, chloroprene rubber, wax, alkyd resin, drying oil, and rosin can also be used.

The most preferred example of the protective layer or the hard coat layer on the substrate surface among the above materials is an ultraviolet curable resin having excellent productivity. The thickness of the protective layer or the hard coat layer on the substrate surface is 0.01 to 30 μm, preferably 0.05 to 1 μm.
0 μm is appropriate. In the present invention, the undercoat layer,
The protective layer and the hard coat layer on the substrate side may contain a stabilizer, a dispersant, a flame retardant, a lubricant, an antistatic agent, a surfactant, a plasticizer, and the like as in the case of the recording layer.

<Protective Substrate> When the protective substrate is irradiated with laser light from the side of the protective substrate, the protective substrate must be transparent to the laser light to be used. Usable substrate materials are exactly the same as the above-mentioned substrate materials, and include polyester, acrylic resin, polyamide, polycarbonate resin, polyolefin resin, phenol resin, epoxy resin, plastic such as polyimide, or glass, ceramic, or metal. Can be used.

<Adhesive, Adhesive Layer> Any known material that can adhere two recording media can be used. In view of productivity, an ultraviolet-curable or hot-melt adhesive is preferable.

[0059]

EXAMPLES Example 1 A compound example A-1 shown in Table 1 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. And a mixture of Compound Example B-3 (for the mixing ratio, see Table 2)
Is dissolved in 2,2,3,3-tetrafluoropropanol, and the solution is applied with a spinner to form an organic dye layer having a thickness of 1000 °.
A reflection layer of 0 ° was provided, and a 5 μm protective layer of an acrylic photopolymer was provided thereon. 0.6 mm thick
The injection molded polycarbonate substrate was bonded with an acrylic photopolymer to obtain a recording medium.

[0060]

[Table 1-1]

[0061]

[Table 1-2]

[0062]

[Table 1-3]

[0063]

[Table 1-4]

[0064]

[Table 1-5]

Examples 2 to 10 Using the combinations of dyes shown in Table 2,
A recording medium was formed in exactly the same manner.

Comparative Example 1 Compound B-3 shown in Table 1 which is trimethine cyanine
A recording medium was formed in exactly the same manner as in Example 1 using only the above.

<Recording Conditions> The recording medium obtained as described above was subjected to a laser oscillation wavelength of 658 nm and a beam diameter of 1.0 μm.
using a semiconductor laser beam of m
An FM signal (linear velocity: 3.5 m / sec.) Was recorded, reproduced by 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> Xe light of 40,000 Lux was continuously irradiated for 20 hours. <Storage test conditions> The device was left at 50 ° C. and 80% for 800 hours. Table 2 shows the evaluation results.

[0069]

[Table 2-1] () Indicates the weight ratio of the dye.

[0070]

[Table 2-2]

[0071]

As described above, according to the detailed and specific description, the recording medium of the present invention enables recording and reproduction with a laser beam in a wavelength range of 670 nm or less, and is excellent in light resistance and storage stability. In particular, it has become possible to provide an optical recording medium having excellent light fastness as compared with the case where a trimethine cyanine dye is used alone. Further, an information recording medium capable of recording and reproducing information with a stable high reflectance and a high degree of modulation could be provided. In addition, a new recording method has become possible by limiting the recording wavelength.

[Brief description of the drawings]

FIG. 1 is a diagram showing a general write-once optical recording medium of the present invention.

FIG. 2 is a diagram showing a configuration of an optical recording medium for CD-R of the present invention.

FIG. 3 is a diagram showing a configuration of an optical recording medium for DVD-R of the present invention.

[Explanation of symbols]

 Reference Signs List 1 substrate (first substrate) 2 recording layer (organic dye layer) 3 undercoat layer 4 protective layer 5 hard coat layer 6 metal reflective layer 7 protective substrate (second substrate) 8 adhesive layer

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) // C09B 23/00 C09B 45/00 45/00 67/22 A 67/22 B41M 5/26 Y (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) Inventor East Yasuhiro 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Co., Ltd. (72) Inventor Noboru 1-3-6 Nakamagome, Ota-ku, Tokyo F-term in Ricoh Co., Ltd. 2H111 EA03 EA12 EA40 EA48 FA01 FA12 FA14 FA23 FA37 FB42 FB43 GA03 GA07 4H056 CA01 CC02 CC08 CE03 DD03 5D029 JA04 JB47 JC05 MA13 WB11 WB14 WC01

Claims (7)

[Claims] An optical recording medium comprising a recording layer provided on a substrate, wherein a trimethine cyanine dye is contained in the recording medium.
An azo compound represented by the following general formula (I) and an azo metal chelate compound composed of a metal are mixed with a trimethine cyanine dye: azo metal chelate compound in a weight ratio of 90:10 to 1
An optical recording medium characterized by containing 0:90. Embedded image In the general formula (I), R ₁ and R ₂ represent a substituent directly bonded to a triazine ring, and R _{3 to} R ₆ are directly bonded to a benzene ring (another aromatic ring may be condensed to the benzene ring). Z represents a bonded substituent, and Z represents a substituent having an active hydrogen group. Here, R ₁ and R ₂ each independently represent a hydrogen atom, a halogen atom, a nitro group, a cyano group, a hydroxyl group, a carboxyl group, an amino group, a carbamoyl group, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group. Group, substituted or unsubstituted heterocyclic residue, substituted or unsubstituted alkyloxy group, substituted or unsubstituted aryloxy group, substituted or unsubstituted alkylthio group, substituted or unsubstituted arylthio group, substituted or unsubstituted Alkylamino group, substituted or unsubstituted arylamino group, substituted or unsubstituted alkyloxycarbonyl group, substituted or unsubstituted aryloxycarbonyl group, substituted or unsubstituted alkylcarboxamide group, substituted or unsubstituted arylcarboxamide Group,
Represents a substituted or unsubstituted alkylcarbamoyl group, a substituted or unsubstituted arylcarbamoyl group, or a substituted or unsubstituted alkenyl group. R _{3 to} R ₆ are selected from the above-mentioned R ₁ and R ₂ substituents. The substituent having an active hydrogen group of Z is a hydroxyl group, a carboxyl group, an amino group, an alkylcarboxamide group, an arylcarboxamide group, an alkylsulfonamide group, an arylsulfonamide group, a carbamoyl group, an alkylcarbamoyl group,
Represents an arylcarbamoyl group, a sulfo group, a sulfino group, a sulfeno group, or a sulfamoyl group. 2. The optical recording medium according to claim 1, wherein the metal atom of the azo metal chelate compound is selected from manganese, cobalt, nickel, and copper. 3. The optical recording medium according to claim 1, wherein the structure of the trimethine cyanine dye is represented by the following general formula (II). Embedded image In the formula (II), R ₇ and R ₈ each represent a substituent directly bonded to a nitrogen atom, Y represents a substituent directly bonded to a benzene ring, and X ⁻ represents a monovalent anion. Here, R ₇ and R ₈ are a substituted or unsubstituted alkyl group. Y is a hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted alkyloxy group. 4. 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 any one of claims 1 to 3, wherein 5. When the reflective layer has a reflective layer, the reflective layer is made of gold, silver,
5. The optical recording medium according to claim 1, wherein the optical recording medium is copper, aluminum, or an alloy of these metals. 6. A track pitch on the substrate is 0.7 to 0.7.
0.8 μm, and the groove width is 0.18 to 0.40 at half width.
The optical recording medium according to claim 1, wherein the optical recording medium has a thickness of μm. 7. The optical recording medium according to claim 1, wherein the recording wavelength is from 600 to 720 nm.