JPH074983B2 - Optical recording medium - Google Patents

Description

TECHNICAL FIELD The present invention relates to a heat mode optical recording medium, and more particularly to an optical recording medium containing a specific compound as a quencher.

(Prior Art) A heat mode optical recording medium uses recording light as heat. For example, a laser or the like melts or removes a part of the medium with the recording light to form pits, thereby forming information. A well-known type is a pit formation type in which recording is performed and the pits are detected by reading light to read out the recording.

In the recording layer of such an optical recording medium, various dyes or a combination of dyes and resins is used. However, such an optical recording medium has a drawback that the sensitivity and the C / N ratio are lowered by repeated erasing, repeated irradiation of reading light, or long-term storage. Therefore, it has been proposed to use a dye and a quencher in combination in order to improve the photostability of the dye, and particularly to prevent decolorization (reproduction deterioration) due to readout light (for example, JP-A-60-162691, 60- 201988, 60−203488, 60−2572
90).

However, even when these quenchers are used together, the durability of the optical recording medium against the reading light or the long-term storage stability cannot be said to be sufficiently satisfactory in practical use.

(Problems to be Solved by the Invention) Therefore, an object of the present invention is to provide an optical recording medium that is durable against repeated irradiation of reading light and has excellent storage stability.

Another object of the present invention is to provide an optical recording medium having improved stability against reading light by using a stabilizer having high solubility in an organic solvent and high miscibility with a dye.

(Means for Solving the Problems) An object of the present invention is to provide a substrate with a dye and the following general formula [I]
Alternatively, it is achieved by an optical recording medium carrying at least one compound represented by [II].

In the formula, [Cat] represents a cation necessary for neutralizing the complex, n represents 1 or 2, M represents Cu, Co, N
i, Pd, and Pt are shown.

R represents a substituted or unsubstituted alkyl group, aryl group or heterocyclic group, and two Rs in the same ligand may be bonded to each other to form a ring.

The present invention will be described in more detail.

Examples of the divalent inorganic cation represented by Cat in the above general formula [I] include alkaline earth metals such as Mg ⁺⁺ and Ca.
^{It can be ++} , Sr ⁺⁺ or Ba ⁺⁺ .

Examples of the divalent organic cation represented by Cat in the general formula [I] include bisonium ion (eg, bisammonium ion, bisphosphonium ion, etc.).

The monovalent inorganic cation represented by Cat in the general formula [I] is, for example, an alkali metal (eg, Li ⁺ , Na ⁺
Or K ^+, etc.), NH ₄ ⁺ can be mentioned. Examples of monovalent organic cations include onium ions (for example, quaternary ammonium ions, quaternary phosphonium ions, and tertiary sulfonium ions).

Among the above-mentioned onium ions, those preferably used in the present invention are those represented by the following general formulas (Ia), (Ib), (Ic) and (I
It can be represented by d), (Ie) or (If).

In the formula, R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ⁸ , R ⁹ , R ¹⁰ ,
R ¹¹ , R ¹² , R ¹³ , R ¹⁴ and R ¹⁵ are each an alkyl group having 1 to 20 carbon atoms (excluding carbon atoms in the substituent portion),
Alternatively, it represents an aryl group having 6 to 14 carbon atoms (excluding carbon atoms in the substituent portion).

R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ⁸ , R ⁹ , R ¹⁰ , R ¹¹ ,
Examples of the alkyl group represented by R ¹² , R ¹³ , R ¹⁴ and R ¹⁵ include a methyl group, an n-butyl group, an iso-amyl group, an n-dodecyl group, an n-octadecyl group and the like. it can. R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ ,
Examples of the aryl group represented by R ⁸ , R ⁹ , R ¹⁰ , R ¹¹ , R ¹² , R ¹³ , R ¹⁴ and R ¹⁵ include a phenyl group or α
-A naphthyl group and the like can be mentioned.

The above-mentioned alkyl group or aryl group is a cyano group, a halogen atom (fluorine atom, chlorine atom, bromine atom, etc.), an alkyl group having 1 to 20 carbon atoms (eg, methyl group, ethyl group, n-butyl group, n- Octyl group, hexadecyl group, octadecyl group or methoxyethoxyethyl group), aryl group having 6 to 14 carbon atoms (eg phenyl group, tolyl group, α-naphthyl group or methoxyphenyl group), 7 to 30 carbon atoms Aralkyl group (eg, benzyl group, 6-phenyloctyl group, anisyl group, etc.), alkoxy group (eg, methoxy group, ethoxy group, propoxy group, butoxy group or methoxyethoxy group), aryloxy group (eg, phenoxy group) , Triloxy or methoxyphenoxy), alkoxycarbonyl Group (eg, methoxycarbonyl group, ethoxycarbonyl group, n-butoxycarbonyl group or phenoxymethoxycarbonyl group), aryloxycarbonyl group (eg, phenoxycarbonyl group, triloxycarbonyl group, or methoxyphenoxycarbonyl group), acyl Group (for example, acetyl group, benzoyl group or p-methoxybenzoyl group), acyloxy group (for example, acetoxy group, benzoyloxy group or p-methoxybenzoyloxy group), acylamino group (for example, acetamide group or benzamide group or Methoxyacetamide group, etc.), anilino group (eg, phenylamino group, N-methylanilino group, N-phenylanilino group or N-acetylanilino group), alkylamido Group (for example, n-butylamino group, N, N-diethylamino group or 4-methoxy-n-butylamino group), carbamoyl group (for example, n-butylcarbamoyl group, or N, N-diethylsulfamoyl group) , An n-dodecylsulfamoyl group or an N- (4-methoxy-n-butyl) sulfamoyl group), a sulfonylamino group (for example, a methylsulfonylamino group, a phenylsulfonylamino group or a methoxymethylsulfonylamino group), or It may be substituted with a sulfonyl group (eg, mesyl group, tosyl group, methoxymethanesulfonyl group, etc.), alkylthio group (eg, methylthio group, butylthio group, dodecylthio group, etc.), arylthio group (eg, phenylthio group, etc.) and the like.

Z ¹ and Z ² each represent a non-metal atom group necessary for forming a substituted or unsubstituted 5-membered ring or 6-membered ring.
Examples of the 5-membered ring or 6-membered ring include a pyridine ring, an imidazole ring, a pyrrole ring, a 2-pyrroline ring, a pyrrolidine ring, a piperidine ring, a pyrazole ring, a pyrazoline ring, an imidazoline ring and the like. The substituents for the 5-membered ring or 6-membered ring represented by Z ¹ and Z ² include those exemplified as the substituents for the groups represented by R ¹ to R ¹⁵ .

Examples of the cation represented by the general formula (Ia) include tetrabutylammonium ion, hexadecylbenzyldimethylammonium ion, tetramethylammonium ion, tetraethylammonium ion, and hexadecyltrimethylammonium ion.

Examples of the cation represented by the general formula (Ib) include dodecylpyridinium ion, hexadecylpyridinium ion, and dodecylimidazolium ion.

Examples of the cation represented by the general formula (Ic) include N-ethyl-N-hexadecylpiperidinium ion and N-ethyl-N-dodecylpyrazolidium ion.

Examples of the cation represented by the general formula (Id) include tetrabutylphosphonium ion, triphenylbenzylphosphonium ion, triphenylbutylphosphonium ion, hexadecyltributylphosphonium ion and the like.

Examples of the cation represented by the general formula (Ie) include hexadecylmethylethylsulfonium ion and dodecylmethylethylsulfonium ion.

Examples of the cation represented by the general formula (If) include bis (triphenylphosphoranylidene) ammonium ion.

Examples of other organic cations include, for example, radical cations formed from neutral organic molecules that easily donate electrons. Examples of these electron donors (neutral molecules) include the following compounds.

In the compounds represented by the above general formulas [I] and [II], the alkyl group represented by R preferably has 1 carbon atom.
To 20 alkyl groups, and examples of the alkyl group include a methyl group, an ethyl group, an n-butyl group, and an n-butyl group.
Hexyl group, n-octyl group, n-dodecyl group, n-octadecyl group, isobutyl group, 2-ethylhexyl group,
Examples thereof include t-butyl group and t-amyl group.

In this case, the alkyl group may be further substituted, and may be a cyano group, a hydroxyl group, a carboxyl group, a sulfo group, a halogen atom (for example, a chlorine atom, a bromine atom or a fluorine atom), an aryl group (for example, a phenyl group, a tolyl group). ,
Naphthyl group, chlorophenyl group, methoxyphenyl group or acetylphenyl group), alkoxy group (eg methoxy group, ethoxy group, butoxy group, propoxy group or methoxyethoxy group), aryloxy group (eg phenoxy group, triloxy group, naphthoxy group) Groups such as methoxyphenoxy group), alkoxycarbonyl groups (eg, methoxycarbonyl group, butoxycarbonyl group or phenoxymethoxycarbonyl group), aryloxycarbonyl groups (eg, phenoxycarbonyl group, triloxycarbonyl group or methoxyphenoxycarbonyl group) Etc.), acyl group (eg formyl group, acetyl group, valeryl group, stearoyl group, benzoyl group, toluoyl group, naphthoyl group or p-methoxybenzoyl group) Etc.), acyloxy group (eg acetoxy group or acyloxy group etc.), acylamino group (eg acetamide group, benzamide group or methoxyacetamide group etc.), anilino group (eg phenylamino group, N-methylanilino group, N- Phenylanilino group, or N-acetylanilino group, etc.), alkylamino group (for example, n-butylamino group, N.N-diethylamino group, 4-methoxy-n-butylamino group, etc.), carbamoyl group (for example, , N-butylcarbamoyl group, N.N-diethylcarbamoyl group, n-butylsulfamoyl group, N.N-diethylsulfamoyl group, n-dodecylsulfamoyl group, or N- (4-methoxy-n -Butyl) sulfamoyl group), sulfonylamino group ( In example, methylsulfonylamino, phenylsulfonylamino group,
Or a methoxymethylsulfonylamino group) or a sulfonyl group (eg, a mesyl group, a tosyl group, a methoxymethanesulfonyl group, etc.) or the like.

The aryl group represented by R is an aryl group having 6 to 14 carbon atoms, particularly preferably a phenyl group.

In this case, the phenyl group may be further substituted, for example, methyl group, methoxy group, halogen atom, nitro group,
It may be substituted with a cyano group or a hydroxyl group.

The heterocyclic group represented by R is a 5- to 6-membered heterocyclic group having at least one nitrogen atom, oxygen atom or sulfur atom in the ring as a hetero atom, and examples thereof include a furyl group, a hydrofuryl group and a thienyl group. , A pyrrolyl group, a pyrrolidine group, a pyridyl group, an imidazolyl group, a pyrazolyl group, a quinolyl group, an indolyl group, an oxazolyl group, a thiazolyl group, and the like, and these heterocyclic groups are further substituted with, for example, a nitro group. May be.

Two R's in the same ligand may combine with each other to form a ring, but in this case, a 5-membered ring to an 8-membered ring is preferable. Further, these rings may contain other heteroatoms such as oxygen atom, nitrogen atom, sulfur atom and the like.

Also, these rings may be substituted (eg,
(Halogen, alkyl group, alkoxy group, aryl group, etc.) and may be condensed with another ring.

The compound represented by the above general formula can be generally produced as follows.

The 1,3-dithiol-2-thione derivative dissolved in anhydrous methanol is opened with a suitable base to convert it to the alkali metal salt of the 1,2-ethylenedithiol derivative. In this solution,
Add the required metal salt and air oxidize. The precipitate formed is filtered. After this is dried, it is extracted with an organic solvent such as dichloromethane, the extract is concentrated, and methanol is slowly added to precipitate crystals of the desired complex.

The preferred compounds among the compounds represented by the above general formula are shown below, but it goes without saying that the present invention is not limited to these exemplified compounds.

The metal complexes represented by the above general formulas [I] and [II] containing the above-exemplified compounds can be synthesized by the method shown in the reference example described below or a method analogous thereto.

There is no particular limitation on the dye contained in the recording layer of the optical recording medium of the present invention. For example, cyanine type, thiazolopyrimidine type, azaazulene type, azulene type, phthalocyanine type, pyrylium or thiapyrylium type, squalium type, quinone type, indoaniline type, naphthalocyanine type, anthraquinone type, azo type, triphenylmethane type, azomethine type System, styryl system, pyrazoline system, aminobenzene system and the like. Of these, preferred are cyanine-based, thiazolopyrimidine-based, azaazulene-based, azulene-based, phthalocyanine-based,
Pyrylium or thiapyrylium series, squalium series,
Quinone-based and indoaniline-based dyes, and particularly preferred are cyanine-based and quinone-based dyes.

Among the cyanine dyes, preferred are those disclosed in JP-A-59-
The one represented by the following general formula described in 178295 is mentioned.

φ-L = ψ ⁺ (X ⁻ ) m In the formula, φ and ψ represent a 5-membered or 6-membered heterocyclic group, and the heterocycle is a benzene ring, a naphthalene ring, 5,
It may form a condensed ring with a 6- or 7-membered heterocycle. Examples of the hetero atom include O, N, S, Se and Te, preferably O, N and S. L is mono-, di-,
Represents a linking group for forming a tri- or tetra-carboxyanine dye. X represents an anion, provides the negative charge necessary to balance the charge of the molecule, and φ or ψ
It may be linked to the above to form an inner salt. m represents 0 or 1.

Among the above cyanine dyes, φ and ψ are particularly preferable. (T ¹ represents C-R ¹⁷ or N, T ² represents C-R ²⁰ or N, and Z ³ represents N-R ²¹ , O, S or R ²¹ , R ²² , R ²³ , and R ^{16 each} represent a substituted or unsubstituted alkyl group or aryl group, and R ¹⁷ , R ¹⁸ , R ¹⁹ , and R
²⁰ is a hydrogen atom or a substituent, for example, an alkyl group, an aryl group, a heterocyclic group, a halogen atom, an alkoxy group,
Represents an alkylthio group, an alkyloxycarbonyl group, an alkylcarbonyloxy group, a carboxylic acid group, or the like, or R ¹⁷ and R ¹⁸ , R ¹⁸ and R ¹⁹ , R ¹⁹ and R ²⁰ , R ²⁰ and R ¹⁶ , R ²¹ and R
²¹ , R ²² and R ²³ may combine to form a ring),
L is CH = CR ²⁴ n (R ²⁴ represents a hydrogen atom, an alkyl group, a phenyl group or a chlorine atom, and n represents an integer of 0 to 3).

Further, examples of preferable thiazolopyrimidine cyanine dyes include compounds represented by the following general formula described in Japanese Patent Application No. 61-178504.

In the formula, A ₁ and A ₂ are each independently a hydrogen atom, a halogen atom, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted aryloxy group, a cyano group, a substituted or unsubstituted alkyl group, a substituted or unsubstituted Represents an aryl group or a substituted or unsubstituted aralkyl group; Y
Represents NR ³⁰ (R ³⁰ represents a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted aralkyl group), O, S, Se, or Te; Z ⁴ Represents an atomic group necessary for forming a 5-membered heterocycle; R ²⁵ , R ²⁶ , R ²⁷ and R ²⁸ are a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, a substituted or unsubstituted Represents an aralkyl group or a hydrogen atom; R ²⁹ is a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, a substituted or unsubstituted aralkyl group, or is bonded to Z ⁴ to form a 6-membered heterocycle. Represents an atomic group necessary for that; n represents 0, 1 or 2, and X represents an anion. However, X is R ²⁵ , R ²⁶ , R ²⁷ , R ²⁸ , R ²⁹ , R
^It may be bonded to ³⁰ , Z ⁴ , A ₁ or A ₂ to form an inner salt.

Examples of preferable azaazulene-based dyes include compounds represented by the following general formula described in Japanese Patent Application No. 61-184500.

R in the formula³¹, R³², R³³, R³⁴, R³⁵, And R³⁶Is a hydrogen atom,
Represents a halogen atom or a monovalent organic residue; A is a double bond
Represents a divalent organic residue bonded by a bond; X Is yin
Represents an on residue. However, X To neutralize the positive charge
There are as many as needed, R³¹, R³², R³³, R³⁴, R³⁵, R³⁶,
Alternatively, it may be bound on A to form an inner salt. or
R³²And R³³, R³³And R³⁴, R³⁴And R³⁵, R³⁵And R³⁶The combination of
A substituted or unsubstituted aromatic with at least one combination
A carbocycle or an aromatic heterocycle may be formed].

Further, examples of preferable imidazoquinoxaline dyes include those represented by the following general formula described in Japanese Patent Application No. 62-245288.

General formula (I) [Wherein R ³⁷ and R ³⁸ represent an alkyl group, an alkenyl group or an aryl group, and L represents a methine group or a linking group formed by linking 3, 5 or 7 methine groups by a conjugated double bond, Z represents an atomic group for completing the aromatic ring, and X ⁻ represents an anion. Examples of other preferable dyes are disclosed in JP-A-57-212639, 58-
36490, 58-112790, 58-112792, 58-114989, 58-125
246, 59-24692, 59-55794, 59-55795, 59-67092, 5
9-71895, 59-81194, 59-83695, 59-124045, 59-12
4897, 59-188854, 59-85791, 59-150795, 59-20289
2, 60-19586, 60-19587, 60-47069, 60-78787, 60
-83236, 60-83892, 60-162691, 60-163243, 60-17
9292, 60-182029, 60-500329, 61-26044, 61-2755
1, 61-47295, 61-226035 and the like.

In the present invention, it is also possible to use a conjugate of the cation of the dye and the anion of the quencher.

The optical recording medium of the present invention is one in which a dye and the quencher are supported on a substrate. The quencher is generally 0.05 to 12 mol, preferably 0.1 to 1 mol per mol of the dye.
Used 1.2 moles.

The quencher is preferably contained in the dye thin film recording layer, but may be contained in a layer other than the recording layer, such as an undercoat layer, a protective layer or a reflective layer. If necessary, the optical recording medium of the present invention may be provided with an undercoat layer on the substrate, and a protective layer and a reflective layer on the recording layer.

Any known substrate can be used as the substrate. Typical examples thereof include glass and plastic, and as the plastic, acrylic, polycarbonate, polysulfone, polyimide, polyester, or the like is used. Various shapes such as a disk shape, a card shape, a sheet shape, and a roll film shape are possible.

A guide groove may be formed on the glass or plastic substrate to facilitate tracking during recording. A glass binder or a plastic substrate may be provided with a plastic binder or an undercoat layer such as an inorganic oxide or an inorganic sulfide. An undercoat layer having a lower thermal conductivity than that of the substrate is preferable. It is also possible to form a so-called air sandwich structure in which two recording media face each other with the recording layers inside.

The recording layer in the present invention is formed, for example, by adding a dye and a quencher to an organic solvent (for example, methanol, ethanol, isopropyl alcohol, dichloromethane, dichloroethane, acetone, methyl ethyl ketone, 2,2,3,3-
Dissolve in tetrafluoropropanol or a mixture thereof, and if necessary, use a suitable binder (eg,
PVA, PVP, polyvinyl butyral, polycarbonate,
(Nitrocellulose, polyvinyl formal, methyl vinyl ether, chlorinated paraffin, maleic anhydride copolymer, styrene-butadiene copolymer, xylene resin)
Can be performed by coating (for example, spin coating) this solution, or by co-evaporating the dye and the quencher, or by vacuum-depositing the dye and then coating the quencher. When using a binder, the weight of the binder is 0.01 of the pigment weight.
2 times is preferable. The dye can also be used as a thin film by the so-called Langmuir-Blodgett method.

The recording layer in the present invention is one layer or two or more layers.

An antioxidant or an anti-fading agent may be present in the recording layer or a layer adjacent thereto in order to prevent deterioration of the dye.

The film layer of the recording layer is usually 0.01 μm to 2 μm, preferably 0.1 μm.
It is in the range of 02 to 0.8 μm. In the case of reflection reading, it is particularly preferably an odd multiple of 1/4 of the laser wavelength used for reading.

When a reflective layer such as a semiconductor laser or a He-Ne laser is provided, a reflective layer is provided on the substrate and then a recording layer is provided on the reflective layer by the method as described above, or
Alternatively, there is a method of providing the recording layer of the substrate and then providing the reflective layer on the recording layer.

The reflective layer can be formed by the following method in addition to the vapor deposition method, the sputtering method, the ion plating method, and the like.

For example, a metal salt or a metal complex salt is dissolved in a water-soluble resin (PVP, PVA, etc.), and a solution containing a reducing agent is applied to the substrate and dried by heating at 50 ° C to 150 ° C, preferably 60 ° C to 100 ° C. To form.

The weight ratio of metal salt or metal complex salt to resin is 0.1.
-10 is preferably 0.5-1.5. At this time, it is suitable that the thin film of the recording layer has a metal particle reflection layer of 0.01 to 0.1 μm and a light absorption layer of 0.01 to 1 μm.

As the metal salt or metal complex salt, silver nitrate, silver cyanide potassium, potassium gold cyanide, silver ammine complex, silver cyan complex, gold salt or gold cyan complex can be used. As the reducing agent, formalin, tartaric acid, tartaric acid salt, hypophosphite, sodium borohydride, dimethylamine borane and the like can be used. The reducing agent can be used in an amount of 0.2 to 10 mol, preferably 0.5 to 4 mol, per 1 mol of the metal salt or metal complex salt.

In the optical recording medium of the present invention, information recording is performed by irradiating a recording layer with a spot-like high energy beam such as a laser (for example, a semiconductor laser, a He-Ne laser) through the substrate or from the side opposite to the substrate. , The light absorbed in the recording layer is exchanged for heat, and pits (holes) are formed in the recording layer.
Is formed.

Information is read by irradiating a laser beam at a low output below the threshold energy of recording and detecting the change in the reflected light amount or transmitted light amount of the bit portion and the portion where no pit is formed.

Next, the present invention will be described in more detail based on Reference Examples and Examples.

Reference Example 1 <Synthesis of Exemplified Compound (3)> 4,5-Synthesized according to a conventional method in 20 ml of anhydrous methanol.
(Ethylenedithio) -1,3-dithiol-2-thione 1.0
Add 2.0 g of potassium hydroxide and stir at 50 ° C for 2 hours. When the reaction solution is left to cool at room temperature, yellow crystals are precipitated. Drain the supernatant as decantation. Add 30 ml of ethanol, decant again and drop the supernatant.

Next, 20 ml of methanol is added to dissolve the crystals. A solution of 0.3 g of nickel chloride (hexahydrate) in 20 ml of methanol was added to this solution under nitrogen with stirring at room temperature and the solution immediately became a dark red color. Stir at room temperature for 2 hours.

Then, when air is blown into it, the reaction liquid becomes dark green immediately. Stir for 30 minutes while inhaling air. When 2 g of tetrabutylphosphonium chloride in powder form is added to this, a precipitate is immediately formed. Stir at room temperature for 30 minutes.

The deposited precipitate is filtered, washed with methanol and air dried. This is dissolved in dichloromethane and filtered. Concentrate the filtrate,
Add hot methanol and allow to cool to room temperature overnight. The crystals precipitated the next day are filtered, washed with methanol and air dried. 0.7 g of black crystals are obtained.

Reference Example 2 <Synthesis of Exemplified Compound (10)> 4,5, which was synthesized according to a conventional method, in 200 ml of anhydrous methanol.
Add 11.8 g of -dibutylthio-1,3-dithiol-2-thione and 4.2 g of potassium hydroxide and reflux for 10 minutes. to this,
While stirring at room temperature under nitrogen, 4.4 g of nickel acetate (tetrahydrate) was added as crystals, and the mixture was stirred for 1.5 hours. This is refluxed for 3 hours in an air atmosphere. After distilling off the solvent of the reaction solution, the residue is extracted with benzene. Concentrate the extract,
Liquid chromatography is performed using silica gel and developed with benzene. The dark green portion is removed, the solvent is distilled off, and n-hexane is added to give a clear solution. When this is left to cool at 5 ° C. overnight, black crystals are precipitated. Next day, filter, wash with n-hexane and air dry.

Yield 1.7g.

Example 1 As shown in Table 1, Dye A, a quencher, and in some cases a binder were dissolved in a mixed solvent of methanol-methyl ethyl ketone-dichloroethane-2,2,3,3-tetrafluoropropanol in an appropriate ratio. Then, the surface-hardened grooved (1.6 μ pitch, depth 750 Å) polycarbonate substrate was coated with a spinner to a thickness of 0.1 μm and dried. The weight ratio of the dye to the quencher is 3: 1, and when the binder is used, the weight of the binder is 1 / the weight of the dye.
It was set to 5.

A signal was recorded on the recording medium thus obtained by using a semiconductor laser, and a weak laser beam was applied to this recording portion to reproduce the signal, and the C / N ratio shown in Table 1 was obtained.

The evaluation conditions were as follows.

(Recording and reproducing) Laser: Semiconductor laser (GaAlAs) Laser wavelength: 830 nm Laser beam diameter: 1.6 μm Linear velocity: 5 m / s Recording power: 8 mW Recording frequency: 2.5 MHz Recording duty: 50% Reproducing power: 0.4 mW ( Evaluation of reproduction deterioration) Reproduction power: 0.8mW Reproduction frequency: 10 ⁵ times Dye A No change in performance was observed even after storage at 60 ° C and 90% humidity for 1 week.

[Solubility test]

The solubility of the compound represented by the following general formula in an organic solvent was measured.

The test compound has the formula Where R'represents the alkylthio group shown in the R'column of Test Nos. 2 and 4 in Table 2.

For comparison, the case where an alkyl group was used as R'was tested, and the results are shown in Test Nos. 1 and 3 of Table 2. Benzene and methylene chloride were chosen as organic solvents.

To measure the solubility, 10 ml of solvent and 1 g of sample were placed in a 20 ml glass test tube with a fitting stopper and placed in a constant temperature bath (15
The mixture was shaken at (° C) for 24 hours, allowed to stand, filtered, the solvent of the filtrate was distilled off, and then the residue was weighed.

From Table 2 it is clear that the compounds of the invention have improved solubility.

(Effect of the Invention) According to the present invention, it is possible to improve the light resistance of an optical recording medium such as an optical disk or an optical card containing a dye, or prevent deterioration during reading by light.

Further, according to the present invention, compared with the conventionally known singlet oxygen quencher, by appropriately selecting and combining the substituents of the metal complex, the solubility in a solvent can be adjusted and the miscibility with a dye can be adjusted. Since it can be made higher, various binders can be widely used.

Claims (1)

[Claims] 1. An optical recording medium comprising a substrate and a dye and at least one compound represented by the following general formula [I] or [II] supported on the substrate. In the formula, [Cat] represents a cation necessary for neutralizing the complex, n represents 1 or 2, M represents Cu, Co, N
i, Pd, and Pt are shown. R represents a substituted or unsubstituted alkyl group, aryl group or heterocyclic group, and two Rs in the same ligand may be bonded to each other to form a ring.