JPH0441066B2 - - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to optical recording media, particularly heat mode optical recording media. Prior Art Optical recording media have the characteristic that the recording medium does not deteriorate due to wear since the medium and the writing or reading head are not in contact with each other, and for this reason, research and development of various optical recording media are being carried out. Among such optical recording media, heat mode optical recording media are being actively developed because they do not require image processing in a darkroom. This heat mode optical recording medium is an optical recording medium that uses recording light as heat. One example is a heat mode optical recording medium that uses recording light such as a laser to melt or remove a part of the medium, which is called a pit. Some devices perform writing by forming small holes, record information using the pits, and read out information by detecting the pits with a readout light. Examples of such pit-forming media include media in which a recording layer made of a light-absorbing dye is formed on a substrate and pits are formed by melting the dye, and media in which pits are formed by melting the dye, and self-oxidizing media such as nitrocellulose. A recording layer containing a thermoplastic resin and a light-absorbing dye is formed, and a recording layer that forms pits by decomposing nitrocellulose, etc., or a recording layer consisting of a thermoplastic resin and a light-absorbing dye is formed, and the resin and Some are known that form pits by melting pigments. By the way, cyanine dyes are known as one of the light-absorbing dyes. However, when forming a recording layer using a cyanine dye, the dye is bleached due to repeated irradiation with readout light during readout after writing.
This method has the disadvantage that the readout S/N ratio deteriorates, that is, the so-called reproduction deterioration is large, and it is not practical. OBJECTS OF THE INVENTION The main object of the present invention is to provide an optical recording medium having a recording layer containing a cyanine dye, in which reproduction deterioration is improved. These objects are achieved by the invention described below. That is, the present invention has a recording layer on a substrate that contains a cyanine dye or a cyanine dye and a resin, and further contains a compound represented by the following general formula [] or [], and prevents the deterioration of the cyanine dye by reproduction light. This is an optical recording medium characterized by the following. General formula [] General formula [] {In the above general formulas [] and [], R ₁ , R ₁ ', R ₁ '' and R ₁ 〓 each represent a hydrogen atom or a monovalent group, R ₂ , R ₃ , R ₄ and R ₅ represents a hydrogen atom or a monovalent group, R ₂ and R ₃ , R ₃ and R ₄ , R ₄ and R ₅ are
They may be combined with each other to form a 6-membered ring. Moreover, M represents a transition metal atom. } Specific Configuration of the Invention The specific configuration of the present invention will be described in detail below. A cyanine dye is contained in the recording layer of the optical recording medium of the present invention. Among the cyanine dyes, those represented by the following formula [] are preferred. Formula [] Φ-L=Ψ (X ^- ) _n In the above formula [], Φ and Ψ are an indole ring, a thiazole ring, to which an aromatic ring, such as a benzene ring, a naphthalene ring, or a phenanthrene ring, may be fused; Represents an oxazole ring, selenazole ring, imidazole ring, pyridine ring, etc. These Φ and Ψ may be the same or different, but are usually the same, and various substituents may be bonded to these rings. In addition,
In Φ, the nitrogen atom in the ring has a positive charge, and in Ψ, the nitrogen atom in the ring is neutral. The skeleton rings of these Φ and Ψ are preferably those represented by the following formulas [Φ] to [Φ]. In addition, in the following, the structure is shown in the form of Φ. In these various rings, the group R ₁ (R ₁ , R ₁ ') bonded to the nitrogen atom in the ring (two nitrogen atoms in the imidazole ring) is a substituted or unsubstituted alkyl group or aryl group. . A group R ₁ bonded to the nitrogen atom in such a ring,
There is no particular restriction on the number of carbon atoms in R ₁ '. Also,
If this group further has a substituent,
Examples of substituents include sulfonic acid groups, alkylcarbonyloxy groups, alkylamide groups, alkylsulfonamide groups, alkoxycarbonyl groups, alkylamino groups, alkylcarbamoyl groups, alkylsulfamoyl groups, hydroxyl groups, carboxy groups, halogen atoms, etc. It may be. In addition, when m described below is 0, the group R ₁ bonded to the nitrogen atom in Φ is a substituted alkyl or aryl group and has a negative charge. Furthermore, when the rings Φ and Ψ are fused or non-fused indole rings (formulas [Φ] to [Φ]), two substituents R ₂ and R ₃ may be bonded to the 3-position. preferable. In this case, the two substituents R ₂ and R ₃ bonded to the 3-position are preferably an alkyl group or an aryl group. and,
Among these, unsubstituted alkyl groups having 1 or 2 carbon atoms, particularly 1, are preferred. On the other hand, another substituent R ₄ may be bonded to a predetermined position in the ring represented by Φ and Ψ. Such substituents include alkyl groups,
It may be a variety of substituents such as an aryl group, a heterocyclic residue, a halogen atom, an alkoxy group, an alkylthio group, an alkyloxycarbonyl group, an alkylcarbonyloxy group, and a carboxylic acid group. Then, the number of these substituents (p, q, r,
s, t) are usually 0 or about 1 to 4. Note that when p, q, r, s, and t are 2 or more, a plurality of R ₄ may be different from each other. Furthermore, among these, the formula [Φ] ~ [Φ
It is preferable to have a fused or non-fused indole ring. This is because these materials have excellent coating properties and stability, exhibit extremely high reflectance, and have an extremely high readout C/N ratio. On the other hand, L represents a linking group for forming a mono-, di-, tri- or tetracarbocyanine dye, and is particularly preferably one of formulas [L] to [L]. Formula [L] Formula [L] Formula [L] Formula [L] Formula [L] Formula [L] Formula [L] Formula [L] Here, Y represents a hydrogen atom or a monovalent group. In this case, the monovalent group includes a lower alkyl group such as a methyl group, a lower alkoxy group such as a methoxy group, a dimethylamino group, a diphenylamino group,
Disubstituted amino groups such as methylphenylamino group, morpholino group, imidazolidine group, ethoxycarbonylpiperazine group, alkylcarbonyloxy group such as acetoxy group, alkylthio group such as methylthio group, cyano group, nitro group, Br, Cl, etc. A halogen atom or the like is preferable. Furthermore, R ₈ and R ₉ each represent a hydrogen atom or a lower alkyl group such as a methyl group. And l is 0 or 1. In addition, in these formulas [L] to [L],
Tricarbocyanine linking group, especially formula [L], [L
] is preferred. Furthermore, X ^- is an anion, preferred examples of which are I ^- , Br ^- , ClO ₄ ^- , BF ₄ ^- ,

【formula】

[Formula] etc. can be mentioned. Note that m is 0 or 1, but when m is 0, R ₁ of Φ usually has a negative charge and becomes an inner salt. Next, specific examples of the cyanine dye of the present invention will be given, but the present invention is not limited to these.

【table】

【table】

[Table] Such dyes can be easily synthesized according to the method described in books such as Dai Organic Chemistry (Asakura Shoten) Nitrogen-Containing Heterocyclic Compounds, page 432. That is, first, the corresponding Φ′−CH ₃ (Φ′ is the above Φ
represents the ring corresponding to . ) is heated with excess R ₁ (R ₁ is an alkyl group or an aryl group) to introduce R ₁ into the nitrogen atom in Φ′ and form Φ−CH ₃ ⁻
get. Next, this may be subjected to dehydration condensation with an unsaturated dialdehyde or an unsaturated hydroxyaldehyde using an alkali catalyst. Further, such a dye is usually contained in the recording layer in the form of a monomer, but may be contained in the form of a polymer if necessary. In this case, the polymer has two or more molecules of a dye, and may be a condensate of these dyes. For example, single or co-condensates of the above dyes having one or more functional groups such as -OH, -COOH, -SO ₃ H, etc., or with these, dialcohols, dicarboxylic acids, or their salts. There are cocondensate components such as diamines, di- and triisocyanates, diepoxy compounds, acid anhydrides, dihydrazides, diiminocarbonates, and cocondensates with other pigments. Alternatively, the dye having the above functional group may be crosslinked with a metal crosslinking agent alone or together with a spacer component or other dye. In this case, the metal crosslinking agents include alkoxides of titanium, zircon, aluminum, etc., chelates of titanium, zircon, aluminum, etc. (e.g., β-diketones, ketoesters, hydroxycarboxylic acids and their esters, ketoalcohols, aminoalcohols, enols) acylates of titanium, zircon, aluminum, etc.). Furthermore, -OH group, -OCCO group and -COOR
One or more types of dyes having at least one group (wherein R is a substituted or unsubstituted alkyl group or aryl group), or this and other spacer components or other dyes It is also possible to use a compound in which the compound is bonded with a -COO- group by a transesterification reaction. In this case, the transesterification reaction is preferably carried out using an alkoxide such as titanium, zircon, or aluminum as a catalyst. In addition, the above dyes may be replaced with resins. In such a case, a resin having a predetermined group is used, and the side chain of the resin is subjected to a condensation reaction, transesterification reaction, or crosslinking, as in the case of the polymer described above. The dyes are linked via a spacer component, etc., if necessary. Furthermore, the recording layer may contain resin. The resin used is preferably a self-oxidizing, depolymerizable or thermoplastic resin. Among these, thermoplastic resins that can be particularly preferably used include the following. () Polyolefin polyethylene, polypropylene, poly4-methylpentene-1, etc. () Polyolefin copolymer For example, ethylene-vinyl acetate copolymer, ethylene-acrylic acid ester copolymer, ethylene-acrylic acid copolymer, ethylene-propylene copolymer, ethylene-butene-1 copolymer,
Ethylene-maleic anhydride copolymer, ethylene propylene terpolymer (EPT), etc. In this case, the polymerization ratio of the comonomers can be arbitrary. () Vinyl chloride copolymer For example, vinyl acetate-vinyl chloride copolymer,
Vinyl chloride-vinylidene chloride copolymer, vinyl chloride-maleic anhydride copolymer, copolymer of acrylic acid ester or methacrylic acid ester and vinyl chloride, acrylonitrile-vinyl chloride copolymer, vinyl chloride ether copolymer,
Ethylene or propylene-vinyl chloride copolymer, ethylene-vinyl acetate copolymer with vinyl chloride graft polymerized, etc. In this case, the copolymerization ratio can be arbitrary. () Vinylidene chloride copolymer Vinylidene chloride-vinyl chloride copolymer, vinylidene chloride-vinyl chloride-acrylonitrile copolymer, vinylidene chloride-butadiene-vinyl halide copolymer, etc. In this case, the copolymerization ratio can be arbitrary. () Polystyrene () Styrene copolymer For example, styrene-acrylonitrile copolymer (AS resin), styrene-acrylonitrile-
Butadiene copolymer (ABS resin), styrene-
Maleic anhydride copolymer (SMA resin), styrene-acrylic acid ester-acrylamide copolymer, styrene-butadiene copolymer (SBR), styrene-vinylidene chloride copolymer,
Styrene-methyl methacrylate copolymer, etc. In this case, the copolymerization ratio can be arbitrary. () Styrene type polymers For example, α-methylstyrene, p-methylstyrene, 2,5-dichlorostyrene, α,β-
Vinylnaphthalene, α-vinylpyridine, acenaphthene, vinylanthracene, etc., or copolymers thereof, such as copolymers of α-methylstyrene and methacrylic acid ester. () Coumarone-indene resin A copolymer of coumaron-indene-styrene. () Terpene resin or picolite For example, terpene resin which is a polymer of limonene obtained from α-pinene, or picolite obtained from β-pinene. () Acrylic resin Particularly preferred is one containing an atomic group represented by the following formula. formula In the above formula, R ₁₀ represents a hydrogen atom or an alkyl group, and R ₂₀ represents a substituted or unsubstituted alkyl group. In this case, in the above formula, R ₁₀ is a hydrogen atom or a carbon atom number of 1 to 1.
4 is preferably a lower alkyl group, particularly a hydrogen atom or a methyl group. Further, R ₂₀ may be a substituted or unsubstituted alkyl group, but the alkyl group preferably has 1 to 8 carbon atoms, and when R ₂₀ is a substituted alkyl group, The substituent for the alkyl group is preferably a hydroxyl group, a halogen atom, or an amino group (particularly a dialkylamino group). Such an atomic group represented by the above formula may form a copolymer with other repeating atomic groups to constitute various acrylic resins, but usually one type of atomic group represented by the above formula is used. Alternatively, an acrylic resin is formed by forming a homopolymer or copolymer having two or more repeating units. (xi) Polyacrylonitrile (xii) Acrylonitrile copolymer For example, acrylonitrile-vinyl acetate copolymer, acrylonitrile-vinyl chloride copolymer, acrylonitrile-styrene copolymer, acrylonitrile-vinylidene chloride copolymer, acrylonitrile-vinylpyridine copolymer polymer, acrylonitrile-methyl methacrylate copolymer, acrylonitrile-butadiene copolymer,
Acrylonitrile-butyl acrylate copolymer, etc. In this case, the copolymerization ratio can be arbitrary. () Diacetone acrylamide polymer Diacetone acrylamide polymer made by reacting acetone with acrylonitrile. () Polyvinyl acetate () Vinyl acetate copolymer For example, a copolymer with acrylic acid ester, vinyl ether, ethylene, vinyl chloride, etc. The copolymerization ratio may be arbitrary. () Polyvinyl ether For example, polyvinyl methyl ether, polyvinyl ethyl ether, polyvinyl butyl ether, etc. () Polyamide In this case, polyamides include nylon 6, nylon 6-6, nylon 6-10, nylon 6-12, nylon 9, nylon 11, nylon
In addition to regular homonylon such as 12 and nylon 13,
Nylon 6/6-6/6-10, Nylon 6/6
-6/12, nylon 6/6-6/11, or modified nylon in some cases. () Polyester For example, oxalic acid, succinic acid, maleic acid,
Various dibasic acids such as aliphatic dibasic acids such as adipic acid and sebastenic acid, or aromatic dibasic acids such as isophthalic acid and terephthalic acid, ethylene glycol, tetramethylene glycol,
Condensates and co-condensates with glycols such as hexamethylene glycol are suitable. Among these, condensates of aliphatic dibasic acids and glycols and cocondensates of glycols and aliphatic dibasic acids are particularly suitable. Furthermore, for example, glyptal resin, which is a condensate of phthalic anhydride and glycerin, can be used as a fatty acid,
Modified glyptal resins that are esterified with natural resins and the like are also preferably used. () Polyvinyl acetal resin Both polyvinyl formal and polyvinyl acetal resin obtained by acetalizing polyvinyl alcohol are preferably used. In this case, the degree of acetalization of the polyvinyl acetal resin can be arbitrary. () Polyurethane resin Thermoplastic polyurethane resin with urethane bonds. Particularly suitable are polyurethane resins obtained by condensation of glycols and diisocyanates, particularly polyurethane resins obtained by condensation of alkylene glycol and alkylene diisocyanate. () Polyether Styrene-formalin resin, ring-opening polymer of cyclic acetal, polyethylene oxide and glycol, polypropylene oxide and glycol, propylene oxide-ethylene oxide copolymer, polyphenylene oxide, etc. () Cellulose derivatives such as nitrocellulose, acetylcellulose, ethylcellulose, acetylbutylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, methylcellulose,
Various esters and ethers of cellulose, such as ethylhydroxyethylcellulose, and mixtures thereof. (xii) Polycarbonate For example, various polycarbonates such as polydioxydiphenylmethane carbonate and dioxydiphenylpropane carbonate. () Ionomer Na, Li, methacrylic acid, acrylic acid, etc.
Zn, Mg salt, etc. () Ketone resin For example, a condensate of a cyclic ketone such as cyclohexanone or acetophenone and formaldehyde. () Xylene resin For example, a condensate of m-xylene or mesitylene and formalin, or a modified product thereof. () Petroleum resins _C5 type, _C9 type, _C5 - _C9 copolymer type, dicyclopentadiene type, or copolymers or modified products thereof. () A blend of two or more of the above () to (), or a blend with other thermoplastic resins. Such self-oxidizing, thermoplastic resin and the above-mentioned dye are usually deposited in a wide range of weight ratio of 1:0.1 to 100. Such a recording layer contains a quencher represented by the above general formula []. This reduces reproduction deterioration of the S/N ratio due to repeated irradiation with readout light. In addition, light resistance is improved by storage in a bright room. In the above general formulas [] and [], R ₁ ,
Even if R ₁ ′, R ₁ ″ and R ₁ are the same,
Although they may be different, each represents a hydrogen atom or a monovalent group. In this case, monovalent groups include alkyl groups, aryl groups, acyl groups, alkoxycarbonyl groups,
Aryloxycarbonyl groups, alkylsulfonyl groups, and arylsulfonyl groups are preferred. Among these, hydrogen atoms, alkyl groups having 1 to 20 carbon atoms, such as methyl groups, ethyl groups, butyl groups, hexyl groups, octyl groups, decyl groups, dodecyl groups, tetradecyl groups,
heptadecyl group, octadecyl group, etc.) Aryl group having 6 to 14 carbon atoms (e.g., phenyl group, tolyl group, naphthyl group, etc.), acyl group having the above alkyl group or aryl group, alkoxycarbonyl group, aryloxycarbonyl group A group, an alkylsulfonyl group, and an arylsulfonyl group are preferred. In addition, each of these monovalent groups includes halogen, cyano group, alkyl group, aryl group, alkoxy group, aryloxy group, aralkyl group, carbonyl group, aryloxycarbonyl group, acyl group, acyloxy group, acylamino group, and alkylamino group. , a carbamoyl group, a sulfamoyl group, a sulfonylamino group, a sulfonyl group, etc. On the other hand, in the general formula [], R ₂ to R ₅ may be the same or different, and each represents a hydrogen atom or a monovalent group. In this case, the monovalent group includes a halogen, a cyano group, or an alkyl group or aryl group bonded directly or via a divalent linking group, respectively.
Heterocyclic residues are preferred. The alkyl group has 1 to 1 carbon atoms.
19 chain to 5- or 6-membered rings; aryl groups include those with 6 to 14 carbon atoms; heterocyclic residues include 5- to 6-membered rings (e.g., furyl, hydrofuryl, Thienil,
(pyrrolyl, pyrrolidyl, pyridyl, imidazolyl, pyrazolyl, quinolyl, indolyl, oxazolyl, liazolyl, etc.) are preferred. Note that these alkyl groups, aryl groups, and heterocyclic residues may be substituted with appropriate substituents. In addition, when these are indirectly bonded to the benzene ring, suitable divalent linking groups include oxy group, thio group, imino group, oxycarbonyl group, carbonyl group, carbonylimino group, sulfimino group, sulfonyl group, etc. It is. Furthermore, R ₂ and R ₃ , R ₃ and R ₄ , and R ₄ and R ₅ may be bonded to each other to form a 6-membered ring, and this 6-membered ring may have a substituent. , and other rings may be fused. For example, benzene, naphthalene, inbenzothiophene, inbenzofuran, isoindoline, etc. Note that M represents a transition metal atom, especially
Ni, Co, Cu, Pd, and Pt are preferred. These compounds represented by the general formula [] are A.
L.Balch, RHHolm, JACS 88 5201 (1966)
etc. are synthesized according to the following. Specific examples of the compound represented by the general formula [] are listed below. In addition, in the following, φ represents a 1,4-phenylene group, and φ' represents a 1,2-phenylene group.

【table】

【table】

[Table] The quencher represented by the general formula [] is 0.01 to 12 mol per mol of dye, especially 0.1 to 12 mol per mol of dye.
Contains about 1.2 moles. Note that the maximum absorption wavelength of the quencher is preferably greater than or equal to the maximum absorption wavelength of the dye used. As a result, reproduction deterioration becomes extremely small. In this case, the difference between the two is preferably 0 or 350 nm or less. In order to form such a recording layer, it is generally necessary to apply it by coating according to a conventional method. The thickness of the recording layer is usually 0.03 to 10 μm.
It is considered to be a degree. In addition, such a recording layer may contain other dyes, other polymers or oligomers, various plasticizers, surfactants, antistatic agents, lubricants, flame retardants, stabilizers, dispersants, and antioxidants. , a crosslinking agent, etc. may be contained. In order to form such a recording layer, it is sufficient to apply a predetermined solvent onto the substrate and dry it. Examples of solvents used for coating include ketones such as methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone, esters such as butyl acetate, ethyl acetate, carbitol acetate, and butyl carbitol acetate, and ethers such as methyl cellosolve and ethyl cellosolve. , aromatic systems such as toluene and xylene, halogenated alkyl systems such as dichloroethane, and alcohol systems. The material of the substrate on which such a recording layer is provided is not particularly limited, and may be any of various resins, glass, ceramics, metals, etc. Further, its shape may be a tape, a drum, a belt, etc. depending on the intended use. Note that the base body usually has a tracking groove. Further, if necessary, it may have a base layer such as a reflective layer, a heat storage layer, a light absorption layer, etc. In addition, resin materials for the base include polymethyl methacrylate, acrylic resin, epoxy resin,
Non-grooved substrates such as polycarbonate resins, polysulfone resins, polyethersulfones, methylpentene polymers, etc. are suitable. These substrates can also be coated with a primer to improve solvent resistance, wettability, surface tension, thermal conductivity, etc. As the primer, for example, titanium-based, silane-based, or aluminum-based coupling agents, various photosensitive resins, and the like can be used. Further, on the recording layer, a reflective layer that functions as a back surface when a transparent substrate is used, various uppermost protective layers, a half mirror layer, etc. can be provided as necessary. The medium of the present invention may have the above-mentioned recording layer on one surface of such a substrate, or may have recording layers on both surfaces thereof. Also,
Two substrates with recording layers coated on one side are used, and the recording layers are placed facing each other with a predetermined gap between them, and they are sealed to prevent dust and scratches. You can also do it like this. Specific effects of the invention When the medium of the invention is running or rotating,
Recording light is irradiated in a pulsed manner. At this time, due to the heat generated by the dye in the recording layer, the dye melts and pits are formed. The pits thus formed are read out by detecting the reflected or transmitted light of the readout light, particularly the reflected light, while the medium is running or rotating. In this case, recording and reading may be performed from the base side or from the recording layer side. It is also possible to erase the pits once formed in the recording layer with light or heat and rewrite. Note that the recording or reading light can be a semiconductor laser, He-Ne laser, Ar laser, He
-Cd laser etc. can be used. Specific Effects of the Invention According to the present invention, reproduction deterioration caused by read light is extremely reduced. Furthermore, the light resistance is improved, and there is little deterioration of characteristics due to storage in a bright room. Further, there is little deterioration in characteristics even when erasing and rewriting are performed. Specific Examples of the Invention Hereinafter, specific examples of the present invention will be shown and the present invention will be explained in further detail. Example 1 Dye D, Resin R, and Quencher Q shown in Table 1 below were dissolved in a predetermined solvent in the proportions shown in Table 1, and deposited on an acrylic disk substrate with a diameter of 15 cm to a thickness of 0.07 μm. A variety of media were obtained by coating and layering. In this case, in Table 1, NC is the nitrogen content
It is nitrocellulose with a viscosity of 11.5-12.2% and 80 seconds based on JIS K 6703. Furthermore, the dyes used were those of the numbers exemplified above. In addition, the quenchers used are indicated by the numbers listed above. Table 1 shows the R/D weight ratio and Q/D
The molar ratio is also written. For each medium created in this way, do this
While rotating at 1800 rpm, AlGaAs-GaAs semiconductor laser recording light (830 nm) was focused to 1 μmφ (focusing section output 10 mW) and irradiated in a pulse train at a predetermined frequency. Each medium was irradiated with write light with a different pulse width, and the pulse width at which an extinction ratio of 1.4 was obtained was measured, and the reciprocal of the pulse width was taken as the write sensitivity. The results are shown in Table 1. In this case, the extinction ratio is the degree of attenuation of the reflectance of the readout light on the medium surface at the pit portion, which will be described later. Separately, writing was performed with a pulse width of 100 nsec. After this, 1mW semiconductor laser (830nm)
Irradiate the readout light as a 1μsec width, 3KHz pulse and measure the initial peak-to-peak C/N ratio on the disk surface and the change in reflectance (%) from the back side of the substrate after 5 minutes of irradiation. did. These results are shown in Table 1. In addition, the comparative quenchers Q1′ and Q2′ are
These are as follows. Q1′ [2,2′-thiobis(4-t-octylphenolate)]-n-butylamine nickel ()
[Siasoap UV-1084 manufactured by Nippon Cyanamid Co., Ltd.] Q2' Nickel bis (octyl phenyl) sulfide [Fero AM-101 manufactured by Nissan Ferro Organic Chemical Co., Ltd.] In addition, DP is a combination of D7 and D105. Cross-linked with i-propoxy-bis(acetylacetonato) titanium, D-R is PMMA (number average molecular weight 10,000),
D8 is linked by ester conversion.

[Table] From the results shown in Table 1, the effects of the present invention are clear. Example 2 Medium No. 4, 5, 6, 7, 8, 9 of Example 1,
10, 12, 13, and 14 in the same manner as in Example 1, then use an infrared heater to heat the medium.
When erasing was performed by heating at 150°C for 15 seconds, it was confirmed that each medium could be successfully erased and rewritten many times.

Claims (1)

[Scope of Claims] 1. A recording layer containing a cyanine dye or a cyanine dye and a resin, and further containing a compound represented by the following general formula [ ] or [ ] on a substrate, which prevents deterioration of the cyanine dye by reproduction light. An optical recording medium characterized by preventing General formula [] General formula [] {In the above general formulas [] and [], R ₁ , R ₁ ′, R ₁ ″ and R ₁ 〓 each represent a hydrogen atom or a monovalent group, and R ₂ , R ₃ , R ₄ and R ₅ , represents a hydrogen atom or a monovalent group, but R ₂ and R ₃ , R ₃ and R ₄ , R ₄ and R ₅ are
They may be combined with each other to form a 6-membered ring. Moreover, M represents a transition metal atom. } 2. The optical recording medium according to claim 1, wherein the cyanine dye is a compound represented by the following general formula []. General formula [] Φ-L=Ψ (X ^- ) _n {In the above general formula [], Φ and Ψ are respectively an indole ring, a thiazole ring, an oxazole ring, a selenazole ring, to which an aromatic ring may be fused, represents an imidazole ring or a pyridine ring; L represents a linking group for forming a mono-, di-, tri- or tetracarbocyanine dye; X ⁻ represents an anion; m is 0 or 1; } 3 The optical recording medium according to claim 2, wherein Φ and Ψ are indole rings to which an aromatic ring may be fused. 4. Claims 1 to 3 in which the cyanine dye is contained in the recording layer in the form of a monomer, in the form of a polymer, or in the form bound to a resin. The optical recording medium according to any of paragraphs.