JPH1035097A - Optical recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical recording medium wherein recording and reproduction at a short wavelength of about 635-680nm can be excellently carried out. SOLUTION: Naphtholactam pigment expressed by the formula is contained in a recording layer. In the formula, R1 expresses an alkyl group, a cycloalkyl group, an alkenyl group, an aryl group, or an aralkyl group. R2 expresses a monovalent substituent. m is 0 or an integer of 1-6. n is 0 or 1. When n is 0, A express a monovalent group derived from a heterocycle, and when n is 1, A expresses a bivalent group derived by removing further one atom of hydrogen from the same atom of monovalent group of a heterocycle. X<-> expresses an anion.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical recording medium using a naphtholactam dye in a recording layer.

[0002]

2. Description of the Related Art The inventors of the present invention have proposed a C (Compact Disc) standard as a recordable optical recording medium conforming to the CD (Compact Disk) standard.
D-R (write-once compact disc) has been developed.
In recent years, further high-density optical recording media have been desired, and one of them is to increase the recording wavelength of CD-R from the existing
Next-generation CD-Rs having a shorter wavelength from 0 to 635 nm have been proposed. The requirements for dyes used in this standard are considered to be almost the same as those for current dyes except for the wavelength.
In addition, there is CD-RII in which the reproduction wavelength is shortened because of compatibility with the current standard. In other words, if the medium recorded by the current recording machine is at least short-wavelength and cannot be read at least, there is a problem that the accumulation of past information cannot be used simply and quickly. Therefore, the recording layer for short wavelength to be developed in the future, while satisfying the Orange Book standard at the current wavelength of 780 nm, is simultaneously 680 nm to 635 nm.
It is important to have characteristics similar to those of the current standard.

In order to satisfy the above characteristics, 78
It is considered possible by mixing or laminating a dye having an absorption near 0 nm and a dye having an absorption on a shorter wavelength side.

As the short-wavelength dye, a trimethine-type cyanine dye has been known for a long time.
However, cyanine dyes generally have low light fastness, and practical use is difficult unless light fastness is improved.

[0005] Further, phthalocyanine dyes which have long been known as high lightfast dyes cannot be developed as dyes for short wavelength dye recording layers due to the problem of absorption wavelength.

On the other hand, the use of a naphtholactam dye in an optical recording medium has been disclosed in JP-A-62-124988 (JP-B-7-29488), JP-A-62-132681 (JP-B8-808), JP-A-62-216972, JP-A-62-216793, JP-A-62-230857
No. (Japanese Patent Publication No. Hei 7-91482), JP-A-63-7797
No. 3, JP-A-1-165669, JP-A-2-1903
No. 89, JP-A-2-190390, JP-A-2-248
287, etc. However, any of the naphtholactam dyes disclosed herein has a recording / reproducing wavelength corresponding to a conventional wavelength around 780 to 830 nm, and does not correspond to a recording / reproducing wavelength of 680 to 635 nm.

As an optical recording medium using a recording / reproducing wavelength of 680 to 635 nm, in addition to the above, a DVD-R (write-once video disk) can be mentioned.

[0008]

SUMMARY OF THE INVENTION An object of the present invention is to firstly use a dye having excellent light resistance and solubility at a wavelength of 680 nm or more.
A high sensitivity having good recording / reproducing characteristics at a wavelength of about 635 nm is to provide an optical recording medium.

Second, good recording and reproduction can be performed even at a wavelength of about 780 nm, the recording and reproduction characteristics conform to the Orange Book standard, and good reproduction can be performed at a wavelength of about 680 to 635 nm. An object of the present invention is to provide a sensitive optical recording medium.

[0010]

This and other objects are achieved by the present invention which is defined below as (1) to (10). (1) An optical recording medium having a recording layer containing a naphtholactam dye represented by the following formula (I).

[0011]

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[In the formula (I), R ₁ is an alkyl group,
Represents a cycloalkyl group, an alkenyl group, an aryl group or an aralkyl group. R ₂ represents a monovalent substituent. m is 0
Or an integer of 1 to 6. n is 0 or 1, and n
Is 0, A represents a monovalent group derived from a heterocyclic ring,
When n is 1, A represents a divalent group derived from the same atom of the heterocyclic monovalent group by further removing one hydrogen atom. X ^-
Represents an anion. (2) The optical recording medium according to the above (1), wherein the heterocyclic group represented by A is a group derived from an indolenine ring. (3) the recording layer further contains a second light-absorbing dye having an optical property different from that of the naphtholactam dye;
The optical recording medium according to the above (1) or (2), wherein recording and reproduction are performed with a first wavelength light of 700 nm and a second wavelength light of 750 to 850 nm. (4) The optical recording medium according to (3), wherein recording is performed with the second wavelength light, and reproduction is performed with the first and second wavelength lights. (5) The real part n of the complex refractive index at 650 nm of the naphtholactam dye is 1.8 to 2.6, and the imaginary part k is 0.02 to 0.02.
0.20, the real part n of the complex refractive index at 780 nm of the second light-absorbing dye is 1.8 to 2.6, and the imaginary part k is 0.0.
The optical recording medium according to the above (3), wherein the recording layer having a half width of the absorption spectrum of the thin film of 170 nm or less is provided on a substrate, and a reflective layer is further provided on the recording layer. (6) A second recording layer containing a second light-absorbing dye having optical characteristics different from that of the naphtholactam dye is laminated on the first recording layer containing the naphtholactam dye,
The optical recording medium according to the above (1) or (2), comprising at least a recording layer. (7) The real part n of the complex refractive index at 650 nm of the naphtholactam dye is 1.8 to 2.6, and the imaginary part k is 0.02 to 0.02.
0.20, the real part n of the complex refractive index at 780 nm of the second light-absorbing dye is 1.8 to 2.6, and the imaginary part k is 0.0.
2 to 0.15, the half width of the absorption spectrum of the thin film is 170 nm or less, the two or more recording layers are provided on a substrate, and the reflection layer is provided on the two or more recording layers. The optical recording medium according to the above (6). (8) The optical recording medium according to the above (6) or (7), wherein a first recording layer is provided on a substrate, and a second recording layer is provided on the first recording layer. (9) The optical recording medium according to any one of the above (3) to (8), wherein the second light absorbing dye is a phthalocyanine dye represented by the following formula (II).

[0013]

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[In the formula (II), M represents a central atom. X ₁ , X ₂ , X ₃ and X ₄ each represent a halogen, which may be the same or different. p
1, p2, p3 and p4 are each 0 or an integer of 1 to 4, and p1 + p2 + p3 + p4 is 0 to 15. Y
₁ , Y ₂ , Y ₃ and Y ₄ each represent an oxygen atom or a sulfur atom, which may be the same or different. Z ₁ , Z ₂ , Z ₃ and Z ₄ each have 4 carbon atoms
The above alkyl groups, alicyclic hydrocarbon groups, aromatic hydrocarbon groups, and heterocyclic groups are the same or different. q1, q2, q3 and q4 are each 0
Or an integer of 1 to 4, which are not simultaneously 0, and q1 + q2 + q3 + q4 is 1 to 8. (10) The first recording layer and the second recording layer each have a thickness of 20 to 200 nm, and the thickness of the first recording layer is divided by the thickness of the second recording layer. The optical recording medium according to the above (8) or (9), wherein the value is 0.1 to 1.

[0015]

Embodiments of the present invention will be described below in detail.

In the optical recording medium of the present invention, the recording layer has the formula (I)
It contains a naphtholactam-based dye represented by [Chemical Formula 3].

In the formula (I), R ₁ represents an alkyl group, a cycloalkyl group, an alkenyl group, an aryl group or an aralkyl group.

The alkyl group represented by R ₁ may be unsubstituted or substituted, and may be linear or branched and have 1 to 20 carbon atoms. preferable. As the substituent, an aryl group such as a phenyl group,
Halogen atom, acyl group having 1 to 4 carbon atoms, carboxy group, acylamino group having 1 to 4 carbon atoms, alkoxycarbonyl group having 2 to 5 carbon atoms, alkoxycarbonylamino group having 2 to 5 carbon atoms, 1 to 4 carbon atoms And an alkylanilino group having an alkyl group. Further, the alkyl group represented by R ₁ may have an oxygen atom interposed.

Examples of the alkyl group represented by R ₁ include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a tert-butyl group, a pentyl group, a 2-methylbutyl group, a hexyl group, 2-methylpentyl, heptyl, octyl, 2-ethylhexyl, isooctyl, nonyl, isononyl, decyl, isodecyl, dodecyl, 3,5,5,7-tetramethylnonyl, isotridecyl Pentadecyl group, hexadecyl group, heptadecyl group, octadecyl group, nonadecyl group, eicosyl group, trifluoromethyl group, trichloromethyl group, 1,1,1-trifluoroethyl group, heptafluoropropyl group, 2-methoxyethyl group, 2-ethoxypropyl group, 3-ethoxypropyl group, 3,6-dioxa Tyl group, 3,6-dioxaoctyl group, 3,6,9-trioxadecyl group, propan-2-one-1-yl group, butan-3-one-1-yl group, 2-ethylpentane- 3-one-1-yl group, 2-
Ethylpentan-3-one-1-yl group, carboxymethyl group, 2-carboxyethyl group, 3-carboxypropyl group, 4-carboxybutyl group, 5-carboxypentyl group, 4-carboxy-3-oxabutyl group, acetyl Aminomethyl group, 2- (acetylamino) -ethyl group, 2- (butyrylamino) -ethyl group, ethoxycarbonylmethyl group, 2- (ethoxycarbonyl) -ethyl group, 3- (methoxycarbonyl) -propyl group, ethoxycarbonyl Aminomethyl group, 2- (ethoxycarbonylamino) -ethyl group, 4-methylanilinomethyl group,
2- (4-isopropylanilino) -ethyl group and the like.

The cycloalkyl group represented by R ₁ may be unsubstituted or substituted, and has 5 to 5 carbon atoms.
7 is preferred. The substituent has 1 to 4 carbon atoms.
And a halogen atom and the like.

Examples of the cycloalkyl group represented by R ₁ include a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a 3-methylcyclopentyl group, a 4-ethylcyclohexyl group, and a 2,3-dichlorocyclohexyl group.

Examples of the alkenyl group represented by R ₁ include an allyl group. The total carbon number of the alkenyl group is 2 to
It is preferably 10.

The aryl group represented by R ₁ may be unsubstituted or substituted, and may be monocyclic or polycyclic. Examples of the substituent include an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a halogen atom, and a dialkylamino group having an alkyl group having 1 to 4 carbon atoms. The total carbon number of the aryl group is 6 to 20
It is preferred that

The aryl group represented by R ₁ includes, for example, phenyl, naphthyl, tolyl, 4-methylphenyl, 4-isopropylphenyl, 4-methoxyphenyl, 2,4-dimethoxyphenyl, Examples thereof include a 2-chlorophenyl group, a 4-bromophenyl group, and a 4-dimethylaminophenyl group.

Examples of the aralkyl group represented by R ₁ include a benzyl group, a phenethyl group, an α-naphthylmethyl group, a β-naphthylmethyl group, a carboxybenzyl group, a sulfobenzyl group and a hydroxybenzyl group. The total number of carbon atoms of the aralkyl group is preferably 7-20.

R ₂ represents a monovalent substituent. Examples of such a substituent include a halogen atom, an alkyl group having 1 to 4 carbon atoms, an aryl group such as a phenyl group, an alkoxy group having 1 to 4 carbon atoms, an alkylthio group having 1 to 20 carbon atoms, a hydroxy group, and an amino group. An acylamino group having 1 to 4 carbon atoms, a nitro group, a mono- or dialkylamino group having an alkyl group having 1 to 4 carbon atoms, an alkylsulfonyl group having 1 to 4 carbon atoms, an alkoxysulfonyl group having 1 to 4 carbon atoms, aryl A sulfonyl group (phenylsulfonyl group, a phenylsulfonyl group substituted with an alkyl group having 1 to 4 carbon atoms, etc.), a hydroxysulfonyl group, an anilino group (anilino group, an alkylanilino group substituted with an alkyl group having 1 to 4 carbon atoms, etc.) ), An acyl group having 1 to 4 carbon atoms, an alkoxycarbonyl group having 2 to 5 carbon atoms, an alkoxycarbonylamino having 2 to 5 carbon atoms , A carbamoyl group (a carbamoyl group, 1 to 4
N-mono or N, N-dialkylcarbamoyl group having an alkyl group of the above), sulfamoyl group (sulfamoyl group, N-mono or N, N-dialkylsulfamoyl group having an alkyl group having 1 to 4 carbon atoms) Ureido group (ureido group, ureido group substituted by an alkyl group having 1 to 4 carbon atoms, etc.), aryloxy group (phenoxy group, etc.), arylthio group (phenylthio group, etc.), and the like. R ₂ may form a ring condensed with a naphthalene ring.

M is 0 or an integer of 1 to 6;
It is preferred that When m is an integer of 2 to 6, each R ₂ may be the same or different. n is 0 or 1, and when n = 0, A is 1 derived from a heterocyclic ring.
A represents a divalent group, and when n is 1, A represents a divalent group derived from the same atom of the heterocyclic monovalent group by further removing one hydrogen atom.

The heterocyclic ring in this case includes a 5- or 6-membered heterocyclic ring and may have a condensed ring. For example, a thiazole ring (eg, thiazole, 4-methylthiazole, 4-phenylthiazole, 5-methylthiazole, 5-phenylthiazole, 4,5-dimethylthiazole, 4,5-diphenylthiazole, 4- (2-
Thienyl) -thiazole, etc.), benzothiazole-based rings (e.g., benzothiazole, 5-chlorobenzothiazole, 5-methylbenzothiazole, 6-methylbenzothiazole, 5,6-dimethylbenzothiazole, 5-
Bromobenzothiazole, 5-phenylbenzothiazole, 5-methoxybenzothiazole, 6-methoxybenzothiazole, 5,6-dimethoxybenzothiazole,
5,6-dioxymethylenebenzothiazole, 5-hydroxybenzothiazole, 6-hydroxybenzothiazole, 4,5,6,7-tetrahydrobenzothiazole and the like, naphthothiazole-based ring (for example, naphtho [2,
1-d] thiazole, naphtho [1,2-d] thiazole, 5-methoxynaphtho [1,2-d] thiazole,
-Ethoxynaphtho [1,2-d] thiazole, 8-methoxynaphtho [2,1-d] thiazole, 7-methoxynaphtho [2,1-d] thiazole and the like, thionaphthene [7,6-d] thiazole (E.g., 7-methoxythionaphthene [7,6-d] thiazole, oxazole-based rings (e.g., 4-methyloxazole, 5-methyloxazole, 4-phenyloxazole, 4,5-diphenyloxazole, 4-ethyloxazole) , 4,5
-Dimethyloxazole, 5-phenyloxazole), benzoxazole-based rings (e.g., benzoxazole, 5-chlorobenzoxazole, 5-methylbenzoxazole, 5-phenylbenzoxazole,
6-methylbenzoxazole, 5,6-dimethylbenzoxazole, 5-methoxybenzoxazole, 6
-Methoxybenzoxazole, 5-hydroxybenzoxazole, 6-hydroxybenzoxazole, etc.), naphthoxazole-based ring (for example, naphtho [2,
1-d] oxazole, naphtho [1,2-d] oxazole and the like), selenazole-based ring (for example, 4-methyl selenazole, 4-phenyl selenazole and the like), and benzo selenazole-based ring (for example, benzo selenazole, 5-
Chlorobenzoselenazole, 5-methylbenzoselenazole, 5,6-dimethylbenzoselenazole, 5-methoxybenzoselenazole, 5-methyl-6-methoxybenzoselenazole, 5,6-dioxymethylenebenzoselenazole, 5-hydroxybenzoselenazole, 4,
5,6,7-tetrahydrobenzoselenazole, etc.),
Naphtho selenazole ring (for example, naphtho [2,1-
d] selenazole, naphtho [1,2-d] selenazole, thiazoline-based ring (for example, thiazoline, 4-methylthiazoline, 4-hydroxymethyl-4-methylthiazoline, 4,4-bis-hydroxymethylthiazoline, etc.), oxazoline Ring (eg, oxazoline), selenazoline ring (eg, selenazoline), 2-quinoline ring (eg, quinoline, 6-methylquinoline, 6-
Chloroquinoline, 6-methoxyquinoline, 6-ethoxyquinoline, 6-hydroxyquinoline), 4-quinoline-based ring (for example, quinoline, 6-methoxyquinoline, 7-methylquinoline, 8-methylquinoline), 1-isoquinoline-based Rings (eg, isoquinoline, 3,4-dihydroisoquinoline), 3-isoquinoline-based rings (eg, isoquinoline), indolenine-based rings, preferably 2-mono-aryl-substituted indolenine-based rings and 3,3-dialkylindines Renin-based rings (for example, 3,3-dimethylindolenine, 3,3-dimethyl-5-chloroindolenine, 3,
3,5-trimethylindolenine, 3,3,7-trimethylindolenine, and those further condensed with a benzene ring, etc., pyridine-based rings (for example, pyridine, 5-methylpyridine), and benzimidazole-based rings (E.g. 1-ethyl-5,6-dichlorobenzimidazole, 1-hydroxyethyl-5,6-dichlorobenzimidazole, 1-ethyl-5-dichlorobenzimidazole, 1-ethyl-5,6-dibromobenzimidazole, 1 -Ethyl-5-phenylbenzimidazole,
1-ethyl-5-fluorobenzimidazole, 1-ethyl-5-dicyanobenzimidazole, 1- (β-acetoxyethyl) -5-dicyanobenzimidazole,
1-ethyl-5-chloro-6-cyanobenzimidazole, 1-ethyl-5-fluoro-6-cyanobenzimidazole, 1-ethyl-5-acetylbenzimidazole, 1-ethyl-5-carboxybenzimidazole,
1-ethyl-5-ethoxycarbonylbenzimidazole, 1-ethyl-5-sulfamylbenzimidazole, 1-ethyl-5-N-ethylsulfamylbenzimidazole, 1-ethyl-5,6-difluorobenzimidazole, 1-ethyl-5,6-dicyanobenzimidazole, 1-ethyl-5-ethylsulfonylbenzimidazole, 1-ethyl-5-methylsulfonylbenzimidazole, 1-ethyl-5-trifluoromethylbenzimidazole, 1-ethyl- 5-trifluoromethylsulfonylbenzimidazole, 1-ethyl-5-trifluoromethylsulfinylbenzimidazole, etc.). In addition, pyran, thiopyran, selenapyran, benzopyran, benzothiopyran,
Benzoselenapyran, naphthopyran, naphthothiopyran, naphthoselenapyran and the like are also mentioned, and these rings may further have a substituent.

Of these, an indolenine ring is preferred, and A is preferably one shown below.

[0030]

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Here, R ₁₀ represents an alkyl group such as a methyl group, and Ar represents an aryl group such as a phenyl group.

[0032] X ^- a represents an anion, such as chloride ion (Cl ^-), a bromide ion (Br ^-), iodide ion (I ^-), tetrafluoroborate ion (BF ₄ ^-),
Hexafluorophosphate ion (PF ₆ ⁻ ), tetraphenyl borate ion (B (C ₆ H ₅ ) ₄ ⁻ ), perchlorate ion (ClO ₄ ⁻ ), tungstate ion (WO ₄ ²⁻ ) and the like. And preferably chloride ion (Cl ⁻ ), tetrafluoroborate ion (BF ₄ ⁻ ), hexafluorophosphate ion (PF ₆ ⁻ ), and perchlorate ion (ClO ₄ ⁻ ). Fluoroborate ion (B
F ₄ ⁻ ) and perchlorate ion (ClO ₄ ⁻ ) are preferred.

Specific examples of the naphtholactam dye used in the present invention will be shown below, but the present invention is not limited thereto. Specific examples are shown by a combination of R ₁ , A, R _{21 to} R ₂₆ , n, and x according to the following formula (I-1).

[0034]

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[0035]

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[0036]

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[0037]

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The following shows a synthesis example. Synthesis Example 1 Dye No. 1 8.5 g of naphtholactam and 1,3,3-trimethyl-2-methyleneindoline in 150 ml of chlorobenzene.
7 g were taken and heated to about 100 ° C. 7.5 ml of phosphorus oxychloride was slowly added dropwise, and after the addition, heating and stirring were continued for 2 hours. Upon cooling to room temperature, the intermediate precipitates as a hydrochloride, and was neutralized in ethanol to obtain an intermediate. Take 9.4 g of this intermediate in 60 ml of toluene,
Methyl iodide was added and the mixture was heated under reflux for 5 hours to obtain 12.9 g of a dye iodide salt. This iodide salt is treated with sodium perchlorate to give 1-methyl-2- (1 ′,
3 ', 3'-trimethyl-2'-indolinylidenemethyl) benz [cd] indolium perchlorate (dye
No. 1) was obtained.

Synthesis Example 2 Dye No. 8 8.5 g of naphtholactam and 150 ml of chlorobenzene
Take 10.4 g of -methyl-2-phenylindole,
Heated to about 100 ° C. 7.5 ml of phosphorus oxychloride was slowly added dropwise, and after the addition, heating and stirring were continued for 2 hours. Upon cooling to room temperature, the intermediate precipitates as a hydrochloride, and was neutralized in ethanol to obtain an intermediate. 10.6 g of this intermediate was taken up in 60 ml of toluene, methyl iodide was added, and the mixture was heated under reflux for 5 hours to obtain 14.4 g of an iodide salt of a dye. This iodide salt is treated with sodium perchlorate to give 1-methyl-2- (1'-methyl-2 '
-Phenyl-3'-indolyl) benz [cd] indolium perchlorate (dye No. 8) was obtained.

Other dyes can be similarly synthesized.

The naphtholactam dye represented by the formula (I) has a melting point (mp) of 200 to 350 ° C. and a λmax (in methanol) of 500 to 650 nm.

These dyes may be used alone or in combination of two or more.

In these dyes, the real part n of the complex refractive index at 650 nm is 1.8 to 2.6, and the imaginary part k is 0 to 0.3.
0.

The dyes n and k are determined by forming a dye film on a predetermined transparent substrate to a thickness of about the recording layer of an optical recording medium, for example, about 40 to 100 nm under the same conditions as the recording layer. To prepare a measurement sample, and then measure the reflectance and transmittance at 650 nm of the measurement sample,
From these measured values, for example, it is calculated according to Kyoritsu Zensho "Optics" Kozo Ishiguro, pages 168 to 178. The reflectance is the reflectance of the measurement sample through the substrate or the reflectance from the dye film side, and is measured by specular reflection (about 5 °).

These compounds have a sufficient solubility in an organic solvent, and have a high solubility in a coating solvent which does not attack a polycarbonate resin (PC) generally used as a substrate material of an optical recording medium.

The recording layer using these compounds is particularly preferably used for a write-once optical recording disk (CD-R). Such a recording layer is preferably formed using a dye-containing coating solution. In particular, it is preferable to use a spin coating method in which a coating solution is spread and applied on a rotating substrate.
In addition, gravure coating, spray coating, dipping, or the like may be used.

As a coating solvent at this time, specifically,
It may be appropriately selected from alcohols (including keto alcohols and ethylene glycol monoalkyl ethers), ketones, esters, ethers, aromatics, alkyl halides and the like.

Of these, alcohols are preferable, and among alcohols, keto alcohols such as diacetone alcohol and ethylene such as ethylene glycol monomethyl ether (methyl cellosolve), ethylene glycol monoethyl ether (ethyl cellosolve) and butyl cellosolve are preferable. A glycol monoalkyl ether (cellosolve) type is preferred. Particularly, ethylene glycol monoalkyl ethers are preferable, and among them, ethylene glycol monoethyl ether (2-ethoxyethanol, ethyl cellosolve) is preferable. These coating solvents are 2
Vapor pressure at 0 ° C is 10.0mmHg or less, usually 0.5 ~
It is 10.0 mmHg. Further, fluorinated alcohols such as 2,2,3,3-tetrafluoropropanol are also preferable. Further, ketones such as cyclohexanenone are also preferable.

After the spin coating as described above, the coating film is dried if necessary. The thickness of the recording layer formed in this way is appropriately set according to the target reflectance and the like, but is usually about 100 to 3000 A, more preferably about 200 to 2000 A.

The pigment content in the coating solution is preferably 0.05 to 10% by weight. Since the naphtholactam dye has good solubility, a coating solution having such a content can be easily prepared. More specifically, the naphtholactam dye of the present invention mainly exhibits good solubility in polar solvents, and includes alcohols, cellosolves, keto alcohols such as diacetone alcohol, ketones such as cyclohexanone, and 2,2,3,3. -Dissolve in 0.5 to 10 wt% in a fluorinated alcohol such as tetrafluoropropanol. Ethyl cellosolve and 2,2, which are suitable coating solvents especially when applied to a polycarbonate disc,
By dissolving at least 10 wt% in 3,3-tetrafluoropropanol, a high-quality spin-coated film can be formed in a short time.

The coating liquid may appropriately contain a binder, a dispersant, a stabilizer and the like.

Particularly, in the present invention, a metal complex quencher which is a singlet oxygen quencher is preferably used in combination with the naphtholactam dye of the formula (I).

Examples of the metal complex quencher include metal complexes such as acetylacetonate-based, bisdithio-α-diketone-based and bisphenyldithiol-based bisdithiol-based, thiocatechol-based, salicylaldehyde oxime-based, and thiobisphenolate-based metal complexes. Quencher.
Among them, a bisphenyldithiol-based metal complex quencher is preferable, and Ni, Cu, C
o, Pd, Pt, etc .;
Is preferred.

The amount of the metal complex quencher used may be 1 to 30% by weight of the naphtholactam dye of the formula (I).

Further, the metal complex quencher may be used in the form of a conjugate in which the counter anion of the naphtholactam dye cation, ie, X ⁻ of the formula (I) is a metal complex quencher anion. Preferred in this case are the anions of the same metal complex quencher as described above, and among them, bisphenyldiol-based metal complex quencher anions are preferred, and the preferred central metal is also the same as described above. The conjugate can be obtained by salt exchange.

The recording layer of the optical recording medium of the present invention may contain other types of light absorbing dyes in addition to the naphtholactam dye. Examples of such dyes include phthalocyanine dyes, cyanine dyes, metal complex dyes, styryl dyes, porphyrin dyes, azo dyes, naphtholactam dyes different from those described above, and formazan metal complexes.

Therefore, in such a case, the recording layer may be applied by including such a dye in the coating solution.

In particular, in the present invention, a short wavelength of about 700 to 600 nm, especially about 680 to 635 nm, and a wavelength of about 750 to 850 nm,
In particular, recording and reproduction can be performed at two wavelengths, a conventional wavelength of about 780 nm, and recording and reproduction can be performed separately for these two wavelengths. In this case, the present invention is suitable for a recording and reproducing method of CD-RII in which recording is performed with a conventional wavelength light of about 780 nm and reproduction is performed with two wavelengths of a short wavelength and a conventional wavelength light of about 780 nm. In such a configuration, it is preferable to use a dye having a different optical property such as an absorption property, that is, a dye having a different optical constant, in addition to the naphtholactam dye of the present invention in the recording layer. It is preferable to contain a dye having an absorption maximum (λmax) of about 680 to 750 nm in addition to the naphtholactam dye of the present invention.
max) may be selected from the above dyes and used. Above all, usually, phthalocyanine dyes and pentamethine cyanine dyes are used.

In particular, when used in a recording layer of CD-RII of the type which performs recording and reproduction at two wavelengths as described above, the naphtholactam dye has a real part n of complex refractive index at 650 nm of 1.8 to 2.0. 6. It is preferable that the imaginary part is 0.02 to 0.20. On the other hand, as a dye to be combined with this,
The real part n of the complex refractive index at 780 nm is 1.8 to 2.6, and the imaginary part k is 0.02 to 0.30, and particularly 0.02 to 0.15 when used for a laminated recording layer. The half width of the absorption spectrum of the thin film, that is, the half width of the spectrum line near λmax is 170 nm or less, preferably 150 nm or less. The lower limit of the half width is not particularly limited, but is usually 50 nm. By using such a half-value width, the reflectance and the degree of modulation in the short wavelength region are sufficient without affecting the absorption characteristics of the naphtholactam dye used in combination. In contrast, the half width is 1
If the wavelength exceeds 70 nm, the absorption edge is applied to the wavelength region of the short wavelength laser, and the reflectance in the short wavelength region is reduced. The half value width was determined by preparing a sample in which a dye film was formed on a transparent substrate so that the transmittance T at the absorption maximum λmax was 25% or less, and measuring the absorption spectrum of this sample. For example, to explain according to the absorption spectrum of FIG. 1, the transmittance T _{1 at} λmax and the transmittance T ₂ which becomes substantially constant without depending on the shift of the wavelength when the wavelength is shifted to the longer wavelength side are obtained. T ₂ and the bottom of the depth of half the width △ lambda half width of up to T ₁ as baseline (base). The thickness of the dye film of the sample is usually about 50 to 150 nm.

The above n and k were determined in the same manner as above, with the measurement wavelengths being 650 nm and 780 nm, respectively.

Such a dye is particularly preferably a phthalocyanine dye represented by the formula (II) [listed in Chemical formula 4].

With respect to the formula (II), in the formula (II), M
Represents a central atom. The central atom represented by M includes a hydrogen atom (2H) or a metal atom. At this time, as the metal atom, groups 1 to 14 of the periodic table (1A to 7A
Group, group 8 or 1B-4B), specifically, Li, Na, K, Mg, Ca, Ba,
Ti, Zr, V, Nb, Ta, Cr, Mo, W, Mn,
Tc, Fe, Co, Ni, Ru, Rh, Pd, Os, I
r, Pt, Cu, Ag, Au, Zn, Cd, Hg, A
l, In, Tl, Si, Ge, Sn, Pb, etc., especially L
i, Na, K, Mg, Ca, Ba, Ti, Zr, V, N
b, Ta, Cr, Mo, W, Mn, Tc, Fe, Co,
Ni, Ru, Rh, Pd, Os, Ir, Pt, Cu, A
g, Au, Cd, Hg, Al, In, Tl, Si, G
e, Sn, and Pb. Among them, Al, S
i, Ge, Sn, Cu, Pd, Ni, Fe, Co, and the like are preferable, and Cu, Pd, Ni, Fe, Co, VO, and the like are particularly preferable in terms of stability over time.

These metal atoms may be in the form of VO to which O is coordinated, such as V, or the like, and may be in the form of metal atoms, such as Si, Al, Ge, Co, Fe, etc. A ligand such as an ether group, an ester group, pyridine or a derivative thereof may be further coordinated above, below, or on one side.

X _{1 to} X ₄ each represent a halogen atom;
Halogen atoms include F, Cl, Br, I and the like. Particularly, Br and F are preferable.

P1, p2, p3 and p4 are each 0 or an integer of 1 to 4, and p1 + p2 + p3 + p4 is 0 to
15 and preferably 0-10.

X _{1 to} X ₄ may be the same or different, and when p 1, p 2, p 3, and p 4 are each an integer of 2 or more, X ₁ , X ₂ , X ₃ , X ₄
They may be the same or different.

Y _{1 to} Y ₄ each represent an oxygen atom or a sulfur atom, and particularly preferably an oxygen atom. Y _{1 to} Y
₄ are usually the same, but may be different. Z
_{1 to} Z ₄ each represent an alkyl group having 4 or more carbon atoms, an alicyclic hydrocarbon group, an aromatic hydrocarbon group or a heterocyclic group,
These may be the same or different.

Each of q1, q2, q3 and q4 is 0 or an integer of 1 to 4, and they are not simultaneously 0, and q1 + q2 + q3 + q4 is 1 to 8, preferably 2 to 6.

The bonding position of Y _{1 to} Y _{4 to} the phthalocyanine ring is preferably at the 3-position and / or 6-position of the phthalocyanine ring (see Chemical formula 10), and it is preferable to include at least one such bond.

[0070]

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The alkyl group represented by Z _{1 to} Z ₄ is preferably an alkyl group having 4 to 16 carbon atoms, and may be linear or branched. preferable. It may have a substituent, and examples of the substituent include a halogen atom (F, Cl, Br, I, etc., particularly preferably F, Br, etc.). Specific examples of such an alkyl group include nC ₄ H ₉ and iC ₄ H
_{9 -, s-C 4 H} 9 -, t-C 4 H 9 -, n-C 5 H 11
—, (CH ₃ ) ₂ CHCH ₂ CH ₂ —, (CH ₃ ) ₃ C
CH ₂ —, (C ₂ H ₅ ) ₂ CH—, C ₂ H ₅ C (CH
_{3) 2 -, n-C} 3 H 7 CH (CH 3) -, n-C 6 H
_{13 -, (CH 3) 2} CHCH 2 CH 2 CH 2 -, (CH
₃ ) ₃ C—CH ₂ —CH ₂ —, n—C ₃ H ₇ CH (CH
_{3) CH 2 -, n-} C 4 H 9 CH (CH 3) -, n-C 7
_{H 15 -, [(CH 3} ) 2 CH] 2 -CH-, n-C 4 H
_{9 CH (CH 3) CH 2} -, (CH 3) 2 CHCH 2 C
_{H (CH 3) CH 2 -} , n-C 8 H 17 -, (CH 3) 3
_{CCH 2 CH (CH 3) CH} 2 -, (CH 3) 2 CHC
_{H (i-C 4 H 9} ) -, n-C 4 H 9 CH (C 2 H 5)
_{CH 2 -, n-C 9} H 19 -, CH 3 CH 2 CH (CH
_{3) CH 2 CH (CH 3} ) CH 2 CH 2 -, (CH 3)
_{2 CHCH 2 CH 2 CH 2 CH} (CH 3) CH 2 -, n
_{-C 3 H 7 CH (CH 3} ) CH 2 CH (CH 3) CH 2
_{-, n-C 10 H 21} -, (CH 3) 3 CCH 2 CH 2 C
_{(CH 3) 2 CH 2 -} , n-C 11 H 23 -, n-C 12 H 25
_{-, n-C 13 H 27} -, n-C 14 H 29 -, n-C 15 H
_{31 -, n-C 16 H} 33 -, n-C 4 F 9 -, i-C 4 F 9
_{-, s-C 4 F 9} -, t-C 4 F 9 - , and the like.

Examples of the alicyclic hydrocarbon group represented by Z _{1 to} Z ₄ include a cyclohexyl group and a cyclopentyl group, and a cyclohexyl group is preferred. These may further have a substituent, and examples of such a substituent include an alkyl group, an aryl group, an alkoxy group, an aryloxy group, an aralkyl group, a halogen atom, a nitro group, a carboxyl group, an ester group, and an acyl group. Group, amino group, amide group, carbamoyl group, sulfonyl group, sulfamoyl group, sulfo group, sulfino group, arylazo group, alkylthio group, arylthio group and the like. Among them, an alkyl group having 1 to 5 carbon atoms (for example, methyl Group, ethyl group, n-propyl group, iso-propyl group, n-butyl group, iso-butyl group, sec-butyl group, tert-
Butyl group, n-pentyl group, iso-pentyl group, ne
o-pentyl group, tert-pentyl group, 1-methylbutyl group), alkoxy group (for example, methoxy group, ethoxy group, propoxy group, isopropoxy group, butoxy group, isobutoxy group, sec-butoxy group, tert-butoxy group), An aryl group (eg, phenyl, tolyl, biphenyl, naphthyl), a halogen atom (eg, F,
Cl, Br, I, preferably F, Br) and the like are preferred.
The substitution position of these substituents is preferably one or both of the adjacent positions of the bonding position of Y _{1 to} Y ₄ , and preferably contains at least one such substitution.

The aromatic hydrocarbon group represented by Z _{1 to} Z ₄ may be a single ring, a group having a condensed ring, or a group having a substituent. Further, the total number of carbon atoms is preferably 6 to 20. Specific examples include a phenyl group and a naphthyl group, and a phenyl group is preferable. These may further have a substituent, and examples of such a substituent include the same as those exemplified for the alicyclic hydrocarbon group, and preferable ones are also the same. The same applies to the preferred substitution position, which is preferably the ortho position of the bonding position of Y _{1 to} Y ₄ , and preferably contains at least one ortho substitution.

The heterocyclic groups represented by Z _{1 to} Z ₄ include:
It may be a single ring or one having a condensed ring, and a compound having a hetero atom of oxygen, nitrogen, sulfur or the like, particularly oxygen or nitrogen, is preferred. Specific examples include a pyridyl group, a furanone-yl group, a pyrazyl group, a pyrazolidyl group, a piperidinone-yl group, a quinoxalyl group, a pyranone-yl group, a thiophenetrion-yl group, and the like.
Furanone-yl groups and the like are preferred. These heterocyclic groups are
The compound may further have a substituent, and examples of the substituent include those exemplified for the alicyclic hydrocarbon group and the aromatic hydrocarbon group, and preferable examples are also the same. In particular, when a carbon atom is present adjacent to the bonding position of Y _{1 to} Y ₄ , it is preferable to have a substituent at such an adjacent position.

Z _{1 to} Z ₄ are preferably an alicyclic hydrocarbon group or an aromatic hydrocarbon group, more preferably a cyclohexyl group or a phenyl group, and particularly preferably at least one of the bonding positions of Y ₁ to Y _4. Are preferably those having a substituent (particularly the above-mentioned preferred substituent) at the adjacent position.

Specific examples of such phthalocyanine dyes are shown below, but the present invention is not limited thereto. Specific examples include X _{11 to} X ₁₄ and X _{15 to} X in the following formula (II-1).
₁₈ , X _{19 to} X ₂₂ , X _{23 to} X ₂₆ and M, and when all of H in X _{11 to} X _{14 and the} like are H,
When it is a substituent, only the substituent itself is shown and H is omitted. In addition, the 3-position, the 6-position, and the 4-position and 5-position in the phthalocyanine ring are respectively the same, and when any one of these has a substituent, only a representative example is shown.

[0077]

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[0078]

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[0079]

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[0080]

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[0081]

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[0082]

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[0083]

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[0084]

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[0085]

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[0086]

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[0087]

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[0088]

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[0089]

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[0090]

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These phthalocyanine dyes are described in JP-A-63-313760, JP-A-63-301261,
The compound can be synthesized with reference to the method described in EP 675489 and the like.

The melting points (mp) of these dyes are 100 to 3
00 ° C.

The phthalocyanine dyes of 780 nm
Are shown in Tables 1 and 2. These n and k are obtained when the thickness of the dye film is 80 nm. Further, the half width of the absorption spectrum of the dye thin film was determined as described above, and these results and λmax (thin film) are also shown.

[0094]

[Table 1]

[0095]

[Table 2]

These dyes may be used alone or in combination of two or more.

As the coating solvent for these phthalocyanine dyes, in addition to the above, aliphatic hydrocarbons are also preferable. Examples of the aliphatic hydrocarbons include n-hexane, cyclohexane, methylcyclohexane, ethylcyclohexane, cyclooctane, dimethylcyclohexane, and dimethylcyclohexane. Preferred are n-octane, iso-propylcyclohexane, tert-butylcyclohexane and the like, and particularly preferred are methylcyclohexane, ethylcyclohexane, dimethylcyclohexane and the like. These aliphatic hydrocarbon solvents have a vapor pressure of 200 mmHg or less at 20 ° C., usually 0.1 mmHg.
It is about 5 to 200 mmHg, and generally has a feature that many of them having a high vapor pressure are easily evaporated and have poor affinity for water.

The naphtholactam dyes and the phthalocyanine dyes used in combination therewith may be used in combination of two or more kinds so as to satisfy the above n and k.

When the recording layer of the optical recording medium for recording and reproducing at two wavelengths is used in a mixed system of two or more types, the naphtholactam dye and the phthalocyanine dye and the pentamethine cyanine dye of the present invention may be used. The ratio of the naphtholactam dye of the present invention to the other dye is preferably 90/10 to 10/90.

Therefore, such a mixed type recording layer may be applied using a coating solution containing such a dye at a predetermined ratio.

When recording and reproduction at two wavelengths are intended, a recording layer in which a layer of the naphtholactam dye of the present invention and a layer of another dye are laminated may be used. The order of lamination may be appropriately selected, and the thickness per layer is usually 20 to 2
What is necessary is just to make it about 00 nm. Such a laminated recording layer may be applied using a coating solution containing each dye.

In the case of such a laminated type recording layer having a two-layer structure, a recording layer lower layer (first recording layer) corresponding to a short wavelength containing a naphtholactam dye of the formula (I) is provided on the substrate side. It is preferable to provide an upper layer (second recording layer) for the 780 nm recording layer containing the phthalocyanine dye of the formula (II) thereon. In this case, the lower layer of the recording layer is preferably thinner than the upper layer of the recording layer, and the ratio of the thickness of the lower layer to the upper layer of the recording layer is preferably such that the lower layer / upper layer is 1/10 to 1/1.

As an optical recording disk having such a recording layer corresponding to two wavelengths or a short wavelength on a substrate,
FIG. 2 shows an example of the configuration. FIG. 2 is a partial sectional view. The optical recording disk 1 shown in FIG. 2 is a contact-type optical recording disk having a reflective layer adhered on a recording layer and capable of reproducing data in compliance with the CD standard. As shown, the optical recording disk 1 has a recording layer 3 containing the naphtholactam dye of the present invention on the surface of a substrate 2, and has a reflective layer 4 and a protective film 5 in close contact with the recording layer 3.

The recording layer 3 is of a two-wavelength type, which is the above-mentioned mixed type or laminated type, or a short-wavelength type, which contains a naphtholactam dye as a main component.

The substrate 2 has a disk shape. In order to enable recording and reproduction from the back side of the substrate 2,
Recording light and reproduction light (wavelength: about 500 to 900 nm, especially about 500 to 700 nm,
About 700 nm, especially about 635-680 nm laser light and about 680-900 nm laser light, especially about 680-780 nm laser light and about 770-900 nm semiconductor laser light,
It is preferable to use a resin or glass which is substantially transparent (preferably at a transmittance of 88% or more) with respect to 50 nm and 780 nm. The size is 64 to 200 in diameter.
mm and a thickness of about 1.2 mm.

As shown in FIG. 2, a tracking groove 23 is formed on the surface of the substrate 2 on which the recording layer 3 is formed.
The groove 23 is preferably a spiral continuous groove having a depth of 0.1 to 0.25 μm, a width of 0.35 to 0.60 μm for a mixed type and a short wavelength type,
In the case of a laminated type, it is preferable that the groove pitch is 0.35 to 0.80 μm and the groove pitch is 1.5 to 1.7 μm. With such a configuration of the groove, a good tracking signal can be obtained without lowering the reflection level of the groove. Particularly, the groove width is set to 0.35 to 0.60.
It is important to regulate the groove width to 0.35 μm or 0.35 to 0.80 μm, and if the groove width is less than 0.35 μm, it is difficult to obtain a tracking signal of a sufficient magnitude,
Due to the slight offset of tracking when recording,
Jitter tends to be large. Also, as the groove width increases, waveform distortion tends to occur.

The substrate 2 is preferably made of a resin, and is preferably made of various thermoplastic resins such as polycarbonate resin, acrylic resin, amorphous polyolefin, TPX, and polystyrene resin. And it can manufacture according to well-known methods, such as injection molding, using such a resin. The groove 23 is preferably formed when the substrate 2 is formed. After the manufacture of the substrate 2, a resin layer having the groove 23 may be formed by a 2P method or the like. In some cases, a glass substrate may be used.

As shown in FIG. 2, the recording layer 3 provided on the substrate 2 is formed by using the above-mentioned dye-containing coating solution, preferably by the spin coating method as described above. The spin coating may be performed under normal conditions, for example, by adjusting the number of revolutions from 500 to 5000 rpm from the inner circumference to the outer circumference.

The recording layer 3 thus formed has a dry film thickness of 50 in the mixed type and the short wavelength type.
It is preferably from 0 to 3000 A (50 to 300 nm). Outside of this range, the reflectivity decreases, making it difficult to perform reproduction conforming to the CD standard. At this time, groove 2
The thickness of the recording layer 3 in the recording track 3 is 1000A.
(100 nm) or more, especially 1300-3000 A (130
３００300 nm), the degree of modulation becomes extremely large.

In the case of the laminated type, as described above,
200 to 2000 A (20 to 200 n
m) is preferable. Thereby, good reproduction can be performed. Further, the thickness of the recording layer 3 in the recording track in the groove 23 is 500 A (50 nm) or more, especially 80
It is preferably from 0 to 1500 A (80 to 150 nm). Furthermore, as described above, when the naphtholactam dye of the present invention is contained in the lower layer in a two-layer structure, the recording and reproduction at 780 nm can be performed satisfactorily by setting the thickness of the upper and lower layers as described above. On the other hand, if the lower layer is too thick, the characteristics at 780 nm are significantly reduced.

The recording layer 3 thus formed is
If the recording layer is of a wavelength-compatible dye-mixing type, then 6
N = 1.8-2.6, k = 0.02 at 50 nm
0.20, n = 2.0-2.6 at 780 nm, k =
It is preferably 0.02 to 0.30. When the recording layer is a two-wavelength type recording layer, n = 1.8 to 2.6 and k = 0.02 to 0.2 at 650 nm.
0, n = 2.0 to 2.6 at 780 nm, k = 0.0
It is preferably from 2 to 0.15. Thus, n, k
, Good recording and reproduction can be performed with two wavelengths. In particular, at a conventional wavelength of about 780 nm, recording and reproduction in accordance with the Orange Book standard can be performed.

In the case of a short wavelength type of about 650 nm, the extinction coefficient (imaginary part of the complex refractive index) k of the recording light and the reproduction light wavelength is preferably 0 to 0.20. . If k exceeds 0.20, a sufficient reflectance cannot be obtained. Further, the refractive index (real part of the complex refractive index) n of the recording layer 3 is preferably 1.8 or more. If n is less than 1.8, the modulation degree of the signal is too small. Although the upper limit of n is not particularly limited, it is usually about 2.6 for convenience in the synthesis of the dye compound.

The recording layers n and k can be determined by preparing a recording sample on a predetermined transparent substrate to a thickness of, for example, about 40 to 100 nm under actual conditions, and preparing a measurement sample. The reflectance is determined by measuring the reflectance of the measurement sample through the substrate or the reflectance from the recording layer side. In this case, the reflectance is measured by specular reflection (about 5 °) using the recording / reproducing light wavelength. Also, the transmittance of the sample is measured. And from these measurements, for example,
According to Kyoritsu Zensho "Optics" Kozo Ishiguro P168-178,
What is necessary is just to calculate n and k.

Incidentally, n and k of such a recording layer are as follows.
Depending on the dye used, the values correspond to the aforementioned n and k of each dye.

As shown in FIG. 2, on the recording layer 3,
The reflection layer 4 is provided in close contact with the substrate. As the reflective layer 4, it is preferable to use a metal or alloy having a high reflectivity such as Au, Cu, Al, or AgCu. The thickness of the reflective layer 4 is preferably 500 A or more, and may be provided by vapor deposition, sputtering, or the like. The upper limit of the thickness is not particularly limited, but is preferably about 1200 A or less in consideration of cost, production operation time and the like. As a result, the reflectance of the reflective layer 4 alone is 90% or more, the reflectance through the substrate of the unrecorded portion of the medium is sufficient, and 780 of the two-wavelength compatible type is used.
At a conventional wavelength of about nm, 60% or more, especially 70% or more can be obtained.

As shown in FIG. 2, on the reflection layer 4,
A protective film 5 is provided. The protective film 5 is made of, for example, various resin materials such as an ultraviolet curable resin, and is usually 0.5 to 100 μm.
It may be formed to a thickness of about m. The protective film 5 may be in the form of a layer or a sheet. The protective film 5 may be formed by an ordinary method such as spin coating, gravure coating, spray coating, dipping, or the like.

For recording or additional recording on the optical recording disk 1 having such a configuration, for example, 650 nm or 780 nm
The recording light of nm is irradiated in a pulse shape through the substrate 2 to change the light reflectance of the irradiated portion. When the recording light is irradiated, the recording layer 3 absorbs the light and generates heat, and at the same time, the substrate 2 is also heated. As a result, in the vicinity of the interface between the substrate 2 and the recording layer 3, the material of the recording layer such as a dye is melted or decomposed, and pressure is applied to the interface between the recording layer 3 and the substrate 2 to deform the bottom and side walls of the groove. Sometimes.

The naphtholactam dye of the formula (I) can be used in the recording layer of a write-once digital video disc (DVD-R) for recording and reproducing at a short wavelength of about 635 to 650 nm.

The disc structure of the DVD-R is a two-layer type, in which a layer having the same structure as that shown in FIG. 2 is provided on a substrate (normally a polycarbonate resin) having a thickness of 0.6 mm, and the protective films are bonded with an adhesive. (Thermoplastic resin, thermosetting resin, etc.).

The substrate is the same as that of the CD described above, except that the groove depth is 0.1 to 0.25 μm, the width is 0.2 to 0.4 μm, and the groove pitch is 0.5 to 1.0.
μm.

The thickness of the recording layer is 500-3000 A, and the complex refractive index at 635 nm is n = 2.0-2.
6, k = 0.02 to 0.20.

[0122]

EXAMPLES Hereinafter, the present invention will be described in more detail by showing specific examples of the present invention.

Example 1 Among the exemplified naphtholactam dyes, No. 1 of 2.
Using a 0 wt% 2,2,3,3, tetrafluoropropanol solution, a dye film is formed on a polycarbonate substrate (120 mm in diameter, 1.2 mm in thickness) by a spin coating method. The spectrum was measured. Dye film thickness (dry film thickness) is 50nm
And The result is shown in FIG. The reflection spectrum was measured both from the dye film side (front surface) and from the substrate side (back surface).

FIG. 3 shows that this compound was 700 to 600 nm
It can be seen that a high reflectivity is exhibited in a wide wavelength range. Therefore, these dyes are recording materials that can sufficiently cope with recording and reproduction at short wavelengths.

Example 2 Light resistance was examined using the thin film sample of Example 1. The light resistance was measured by measuring the initial transmittance T ₀ , further irradiating a xenon lamp (xenon fade meter manufactured by Shimadzu Corporation) with an 80,000 lux, measuring the transmittance T after irradiation, and (100−T) ×
The dye remaining rate (%) was calculated and determined at 100 / (100-T ₀ ). When the dye residual ratio after irradiation for 100 hours was examined, it was about 98%.

From this, it was found that Dye No. 1 had sufficient light fastness.

Example 3 An optical recording disk was produced using the same dye No. 1 as in Example 1 as a dye for a recording layer. First, a pre-groove (depth 0.
12μm, width 0.30μm, groove pitch 0.8μm
) Was formed on a polycarbonate resin substrate having a diameter of 120 mm and a thickness of 0.6 mm by spin coating to form a recording layer containing a dye to a thickness of 2000 A (200 nm). In this case, 2 wt% of 2,2,3,3
-A tetrafluoropropanol solution was used. Next, an Au reflection layer was formed on this recording layer to a thickness of 850 A by a sputtering method, and a transparent protective film (thickness: 5 μm) of an ultraviolet curable acrylic resin was formed. These were laminated using a hot-melt adhesive so that the two protective films were in contact with each other to produce a DVD-R disc. In this case, the thickness of the adhesive was 30 μm on one side and a total of 60 μm. This is designated as disk sample No. 1.

In disk sample No. 1, the dye N
Using o.2, a disk sample No. 2 was prepared in the same manner except that a 3.0 wt% 2-ethoxyethanol solution was prepared and a recording layer was formed using this solution.

EFM was performed on the disk samples No. 1 and No. 2 of the optical recording disk manufactured in this manner using a laser (oscillation wavelength: 635 nm) at a linear velocity of 1.2 m / sec.
-Record a CD format signal and record the optimum recording power (P
₀ ) and Jitter were measured. The optimum recording power means a range in which the asymmetry is -2% with an evaluator (manufactured by Pulstec) used for recording evaluation. Table 3 shows the results. With respect to jitter, deterioration of jitter when light was irradiated under the same conditions as in Example 2 was also evaluated. It is determined that the optimum recording power (P ₀ ) is 8.0 mW or less and the jitter (Jitter) is 100 ns or less.

[0130]

[Table 3]

As is clear from Table 3, an optical recording disk which satisfies the standard values for both the optimum recording power and the jitter can be obtained by using the naphtholactam dye of the present invention. Also, reproduction deterioration due to light is small.

Example 4 In disk samples No. 1 and No. 2 of Example 3,
The metal complex quencher shown below was added to each coating solution for forming the recording layer so that the weight ratio of the dye / quencher was 85/15, and the total amount of the dye and the quencher was 2 wt%.
A disk sample was prepared in the same manner except that the recording layer was formed using a coating solution of 3 wt%. According to the disc sample No. 1 and No. 2, the disc sample No.
11, No. 12.

The characteristics of these samples were evaluated in the same manner as in Example 3, and disk samples No. 1 and No. 2 were evaluated.
Optimum recording power and jitter equivalent to those were shown. In addition, it was found that the jitter after light irradiation did not change much, and the reproduction deterioration due to light was further prevented.

[0134]

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In Examples 3 and 4, the dye No.
Dye No. 8 or Dye No. 1, 2 instead of 1, 2
Disk samples were prepared in the same manner using two or more of these dyes, and the characteristics were evaluated in the same manner. The same results as in Examples 3 and 4 were obtained.

Example 5 Using the same dye No. 1 as in Example 1 and dye A-3 which is an exemplary compound of the phthalocyanine dye of the formula (II),
Optical recording disks for wavelength recording and reproduction were produced.

Dye No. 1 had a λmax of 650 nm when a thin film sample having a dye thickness of 80 nm was used, and n and k at 650 nm obtained by the above method were n = 2.0.
5, k = 0.05.

Dye A-3 was used in a thin film sample having a dye film thickness of 80 nm, λmax = 725 nm, half width at 125 nm,
n = 2.4 and k = 0.10.

Pre-groove (depth 0.18 μm, width 0.
A 0.2 wt% solution of dye No. 1 in 2,2,3,3-tetrafluoropropanol is spin-coated on a polycarbonate resin substrate having a diameter of 120 mm and a thickness of 1.2 mm having a thickness of 55 μm and a groove pitch of 1.55 μm). Coating was carried out by a method and dried at 60 ° C. for 3 hours to form a lower layer of a recording layer having a thickness of 500 Å.

On the lower layer of this recording layer, 2.0 wt.
% Of an ethylcyclohexane solution was applied by a spin coating method, and dried at 60 ° C. for 3 hours to form an upper layer of a recording layer having a thickness of 1000 Å.

On the recording layer having such a two-layer structure, an Au reflection layer was formed to a thickness of 850 A by sputtering, and an ultraviolet-curable acrylic resin was used as a protective film to a thickness of 5 μm.
It was formed in thickness.

Thus, the disk sample No. 51
Was prepared.

The disc sample No. 51 was recorded in accordance with the Orange Book standard using a laser beam of 780 nm according to the third embodiment.
The degree of modulation (I) when reproduced using a 50 nm laser beam
₁₁ Mod), jitter (Jitter) and reflectance (Rto
p) was measured.

In this case, the modulation degree is 59% and the jitter is 2
8 ns and Rtop 32%. Since the required value in such recording and reproduction is Rtop × I ₁₁ Mod> 0.12, the disc sample No. 51 has a value of 0.
It was found to be about 19, which sufficiently satisfied the standard.

Further, the disk sample No. 51 recorded at 780 nm as described above was measured for its modulation degree, jitter and Rtop when reproduced using a 780 nm laser beam. The modulation degree was 67% and the jitter was 67%. Is 22 ns, R
The top was 69%, which proved to meet the Orange Book standard.

Using a laser beam of 650 nm, recording was performed on the disk sample No. 51 (linear velocity: 1.2 m / sec).
Was performed with 650 nm laser light.
Good reproduction could be performed.

Further, when reproduction was carried out with respect to the disk sample No. 51 recorded by using the laser light of 650 nm with the laser light of 780 nm, good reproduction was able to be carried out.

As described above, the disc sample No.
It can be seen that 51 can be favorably used as an optical recording disk of a two-wavelength type.

Example 6 Using the same combination of dyes as in Example 5, a mixed-type optical recording disk for two-wavelength recording and reproduction was produced.

Pre-groove (depth 0.16 μm, width 0.
Dye No. 1 and Dye A-3 (Dye No. 1 / Dye A-3) were placed on a polycarbonate resin substrate having a diameter of 120 mm and a thickness of 1.2 mm having a groove pitch of 45 μm and a groove pitch of 1.55 μm).
(Weight ratio of 60/40) was applied by a spin coating method and dried at 60 ° C. for 3 hours to form a recording layer having a thickness of 1200 Å.

An Au reflective layer was formed on this recording layer to a thickness of 850 A by sputtering, and a UV-curable acrylic resin was formed to a thickness of 5 μm as a protective film.

Thus, an optical recording disk No. 61 was manufactured.

The characteristics were evaluated in the same manner as in Example 5, and the same good results were obtained.

Example 7 In the disk sample No. 61 of Example 6, the same quencher as in Example 4 was added to the dye solution for forming the recording layer.
No. 1 / quencher was added so as to have a weight ratio of 85/15, and dye No. 1 + quencher / dye A-3 was added.
The recording layer was formed in the same manner using a 2.5 wt% ethoxyethanol solution having a weight ratio of 60/40, and disk sample No. 71 was manufactured in the same manner.

When the characteristics of this disk sample No. 71 were evaluated in the same manner as in Example 6, the same excellent results were shown.

When recording was performed at 780 nm and reproduction was performed at 650 nm, jitter after light irradiation under the same conditions as in Example 2 was measured. As a result, disk sample No. 71 was compared with disk sample No. 61. It was found that there was no deterioration and the characteristics were improved in terms of reproduction deterioration.

Example 8 A disk sample was prepared in the same manner as in Examples 5 to 7 except that the combination of dyes used for the recording layer was as follows, and the same results as in Examples 5 to 7 were obtained. Was. Note that λmax, n, k, etc. were obtained under the same conditions as in the fifth embodiment.

Naphtholactam Dye of Formula (I) Phthalocyanine Dye of Formula (II) 1) No. 1 (λmax = 650 nm, A-24 (λmax = 725 nm, half width = 125 nm, n = 2.05, k = 0.05) n = 2.20, k = 0.11) 2) No. 2 (λmax = 522nm, A-1 (λmax = 724nm, half width = 130nm, n = 2.10, k = 0.07) n = 2.20, k = 0.08) 3) No .2 (λmax = 522 nm, A-24 (λmax = 725 nm, half-width = 125 nm, n = 2.10, k = 0.07) n = 2.20, k = 0.11) 4) No. 8 (λmax = 525 nm, A-28 ( λmax = 725 nm, half width = 130 nm, n = 2.00, k = 0.03) n = 2.4, k = 0.09) 5) No. 8 (λmax = 525 nm, A-24 (λmax = 725 nm, half width = 125 nm, n = 2.00, k = 0.03) n = 2.20, k = 0.11)

[0159]

According to the present invention, an optical recording medium having excellent characteristics such as high recording sensitivity and low jitter can be obtained by using a naphtholactam dye excellent in solubility and light resistance as a light absorbing dye. Also, by mixing or laminating with a dye having absorption on the long wavelength side, an optical recording medium compatible with two wavelengths can be obtained, and excellent characteristics can be realized.

[Brief description of the drawings]

FIG. 1 is a graph illustrating a method of obtaining a half width of an absorption spectrum of a thin film of a phthalocyanine dye.

FIG. 2 is a partial sectional view showing an example of the optical disc of the present invention.

FIG. 3 is a graph showing a transmission spectrum and a reflection spectrum of a naphtholactam dye used in the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Optical recording disk 2 Substrate 23 Groove 3 Recording layer 4 Reflective layer 5 Protective film

Continuing on the front page (72) Inventor Yoshio Abe 1-7-6, Nihonbashi Bakurocho, Chuo-ku, Tokyo Inside Dainichi Seika Kogyo Co., Ltd. (72) Inventor Sumiko Kitagawa 1-13-1 Nihonbashi, Chuo-ku, Tokyo Inside (72) Inventor Masahiro Shinkai 1-13-1 Nihonbashi, Chuo-ku, Tokyo TDK Corporation (72) Inventor Noriyoshi Nanba 1-13-1 Nihonbashi, Chuo-ku, Tokyo TDK Corporation

Claims (10)

[Claims] 1. An optical recording medium having a recording layer containing a naphtholactam dye represented by the following formula (I). Embedded image [In the formula (I), R ₁ represents an alkyl group, a cycloalkyl group, an alkenyl group, an aryl group or an aralkyl group. R ₂ represents a monovalent substituent. m is 0 or 1 to 6
Is an integer. n is 0 or 1, and when n is 0, A
Represents a monovalent group derived from a heterocycle, and when n is 1, A represents a divalent group derived from the same atom of the monovalent group of the heterocycle by further removing one hydrogen atom. X ^- represents an anion. ] 2. The optical recording medium according to claim 1, wherein the heterocyclic group represented by A is a group derived from an indolenine ring. 3. The recording layer further contains a second light-absorbing dye having optical characteristics different from those of the naphtholactam dye, a first wavelength light of 600 to 700 nm and a wavelength of 750 to 8 nm.
3. The optical recording medium according to claim 1, wherein recording and reproduction are performed with a second wavelength light of 50 nm. 4. The optical recording medium according to claim 3, wherein recording is performed with the second wavelength light, and reproduction is performed with the first and second wavelength lights. 5. The complex refractive index at 650 nm of the naphtholactam-based dye, wherein the real part n is 1.8 to 2.6 and the imaginary part k is 0.1.
02 to 0.20, and 780 of the second light-absorbing dye.
The recording layer in which the real part n of the complex refractive index in nm is 1.8 to 2.6, the imaginary part k is 0.02 to 0.30, and the half width of the absorption spectrum of the thin film is 170 nm or less. 4. The optical recording medium according to claim 3, wherein the optical recording medium is provided on a substrate and further provided with a reflective layer on the recording layer. 6. A second recording layer containing a second light-absorbing dye having optical characteristics different from that of the naphtholactam-based dye is laminated on the first recording layer containing the naphtholactam-based dye. 3. The optical recording medium according to claim 1, wherein said recording layer is a recording layer. 7. The complex refractive index of the naphtholactam dye at 650 nm is such that the real part n is 1.8 to 2.6 and the imaginary part k is 0.1.
02 to 0.20, and 780 of the second light-absorbing dye.
the real part n of the complex refractive index in nm is 1.8 to 2.6, the imaginary part k is 0.02 to 0.15, the half width of the absorption spectrum of the thin film is 170 nm or less, 7. The optical recording medium according to claim 6, wherein said recording layer is provided on a substrate, and a reflection layer is provided on said two or more recording layers. 8. A first recording layer is provided on a substrate.
8. The optical recording medium according to claim 6, wherein a second recording layer is provided on said recording layer. 9. The optical recording medium according to claim 3, wherein the second light absorbing dye is a phthalocyanine dye represented by the following formula (II). Embedded image [In the formula (II), M represents a central atom. X ₁ , X
₂ , X ₃ and X ₄ each represent a halogen, which may be the same or different. p1, p2, p3
And p4 are each 0 or an integer of 1 to 4, and p1 +
p2 + p3 + p4 is 0-15. Y ₁ , Y ₂ , Y ₃
And Y ₄ each represent an oxygen atom or a sulfur atom, which may be the same or different. Z ₁ , Z
₂ , Z ₃ and Z ₄ each represent an alkyl group having 4 or more carbon atoms, an alicyclic hydrocarbon group, an aromatic hydrocarbon group or a heterocyclic group, which may be the same or different. q1, q2, q3 and q4 are each 0 or 1-4.
Which are not simultaneously 0, and q
1 + q2 + q3 + q4 is 1 to 8. ] 10. The film thickness of each of the first recording layer and the second recording layer is 20 to 200 nm, and the film thickness of the first recording layer is divided by the film thickness of the second recording layer. Is 0.
10. The optical recording medium according to claim 8, wherein the optical recording medium is 1 to 1.