JP4534089B2 - Optical information recording medium and information recording method - Google Patents

Description

  The present invention relates to an optical information recording medium and an information recording method capable of recording and reproducing information using a laser beam. In particular, the present invention relates to a heat mode type optical information recording medium suitable for recording information using a short wavelength laser beam selected from a wavelength range of 390 to 430 nm.

  Conventionally, an optical information recording medium (optical disk) capable of recording information only once by laser light is known. This optical disk is also referred to as a recordable CD (so-called CD-R), and its typical structure is a recording layer made of an organic dye on a transparent disk-shaped substrate, a light reflecting layer made of a metal such as gold, and a resin. The protective layers are provided in a laminated state in this order. Information recording on this CD-R is performed by irradiating the CD-R with a near-infrared laser beam (usually a laser beam having a wavelength of around 780 nm), and the irradiated portion of the recording layer emits the light. Information is recorded by absorbing and locally raising the temperature, causing a physical or chemical change (eg, pit formation) and changing its optical properties. On the other hand, reading (reproduction) of information is also performed by irradiating laser light having the same wavelength as that of the recording laser light, and the portion where the optical characteristics of the recording layer have changed (recorded portion) and the portion not changed (unrecorded) Information is reproduced by detecting the difference in reflectance from (part).

  In recent years, an optical information recording medium having a higher recording density has been demanded. In response to such a demand, an optical disc called a write-once digital versatile disc (so-called DVD-R) has been proposed (see, for example, Non-Patent Document 1). This DVD-R is a transparent disk-shaped substrate in which the guide groove (pre-groove) for tracking the irradiated laser beam is narrower than half of the CD-R (0.74-0.8 μm). On top of this, a recording layer made of a dye, and usually two light reflecting layers on the recording layer, and further a protective layer provided if necessary, or a disk-shaped protective substrate having the same shape as the disk It has a structure in which the recording layer is inside and bonded with an adhesive. Information recording / reproduction to / from DVD-R is performed by irradiating visible laser light (usually laser light having a wavelength in the range of 630 to 680 nm), and higher density recording than CD-R is possible. ing.

  Recently, networks such as the Internet and high-definition TV are rapidly spreading. In addition, broadcasting of HDTV (High Definition Television) has started, and a demand for a large-capacity recording medium is increasing in order to record image information inexpensively and easily. Although the DVD-R is secured to a certain extent as a large-capacity recording medium, it cannot be said that the DVD-R has a large enough recording capacity to meet future requirements. Therefore, development of an optical disc having a higher recording capacity by improving the recording density by using a laser beam having a wavelength shorter than that of the DVD-R is underway.

  Conventionally, in an optical information recording medium having a recording layer containing an organic dye, a recording / reproducing method for recording / reproducing information by irradiating a laser beam having a wavelength of 530 nm or less from the recording layer side toward the light reflecting layer side has been proposed. (For example, refer to Patent Documents 1 to 16.)

Specifically, as an optical disc using a porphyrin compound, an azo dye, a metal azo dye, a quinophthalone dye, a trimethine cyanine dye, a dicyanovinylphenyl skeleton dye, a coumarin compound, a naphthalocyanine compound, etc. There has been proposed an information recording / reproducing method for recording / reproducing information by irradiating a blue (wavelength 430 nm, 488 nm) or blue-green (wavelength 515 nm) laser beam.
"Nikkei New Media" separate volume DVD, 1995 JP-A-4-74690 JP-A-7-304256 JP-A-7-304257 JP-A-8-127174 Japanese Patent Laid-Open No. 11-53758 JP-A-11-334204 JP 11-334205 A Japanese Patent Laid-Open No. 11-334206 JP 11-334207 A JP 2000-43423 A (Claims) JP 2000-108513 A (Claims) JP 2000-11504 A (Claims) JP 2000-149320 A (Claims) JP 2000-158818 A (Claims) JP 2000-228028 A (Claims) JP 2004-90564 A (Claims)

  As a result of the study by the present inventor, it has been found that the optical disk described in the above publication is still insufficient in terms of practical sensitivity and recording characteristics such as reflectivity and modulation degree, and therefore further improvement is required.

  Therefore, the object of the present invention is to enable recording / reproduction with a laser beam having a shorter wavelength than that of CD-R or DVD-R, in particular, a semiconductor laser beam having a wavelength of 390 to 430 nm, particularly a highly versatile wavelength of 400 to 410 nm. The present invention also provides an optical information recording medium having excellent recording characteristics. Another object of the present invention is to provide an information recording method capable of recording information at high density by using an optical information recording medium provided with a recording layer containing a dye compound exhibiting high sensitivity to short wavelength laser light. It is to be.

  The above object of the present invention can be achieved by the following configuration.

  1. An optical information recording medium comprising a recording layer capable of recording information by laser beam irradiation, containing at least one metal chelate compound having a compound represented by the following general formula (1) as a ligand.

(In the formula, A represents the following general formula (2) or (3), X represents a group having active hydrogen, Y represents O, S, NR ₅ , R ₁ , R ₂ , R ₃ , R ₄ and R ₅ each independently represents a hydrogen atom or a substituent.)

(In the formula, X ₁ is necessary to form a 5- or 6-membered monocyclic aromatic heterocyclic ring or a condensed aromatic heterocyclic ring together with the carbon atom bonded to the azo group and the nitrogen atom bonded to the carbon atom. Represents an atomic group, and these aromatic heterocycles may have a substituent.)

(In the formula, X ₂ is a 5- to 6-membered monocyclic aromatic carbocycle or aromatic heterocycle together with a carbon atom bonded to an azo group and a carbon atom containing a substituent G bonded to the carbon atom, or Represents a group of atoms necessary to form a fused aromatic carbocyclic ring or aromatic heterocyclic ring, and these aromatic carbocyclic rings or aromatic heterocyclic rings may further have a substituent, and G can be chelated. And G may combine with X ₂ to form a ring.)
2. 2. The optical information recording medium as described in 1 above, wherein the laser beam irradiation is selected from a range of wavelengths from 390 to 430 nm.

3 . 3. An information recording method for recording information by irradiating the optical information recording medium according to 1 or 2 with a laser beam selected from a wavelength range of 390 to 430 nm.

  The present invention shows a high reflectivity with respect to a short-wavelength laser beam having a wavelength of 390 to 430 nm by using a metal chelate compound having the compound represented by the general formula (1) as a ligand for the recording layer. In addition, a highly sensitive optical information recording medium that gives a high degree of modulation can be obtained. Accordingly, it is possible to provide an optical information recording medium capable of recording information at a higher density than in the case of CD-R and DVD-R, and capable of recording a larger amount of information. A recording layer containing a metal chelate compound having a ligand represented by the compound represented by the general formula (1) exhibiting high sensitivity to short wavelength laser light, particularly to short wavelength laser light having a wavelength of 390 to 430 nm. By using the provided optical information recording medium, an information recording method capable of recording information at high density can be provided.

  The present invention will be described in more detail. The optical information recording medium of the present invention has a recording layer capable of recording information by laser light irradiation, and a metal chelate compound comprising a compound represented by the general formula (1) as a ligand in the recording layer. It contains at least one kind or a mixture of at least one kind of the compound represented by the general formula (1) and a metal ion-containing compound.

  Hereinafter, although the best mode for carrying out the present invention will be described, the present invention is not limited to these.

  First, the compound represented by the general formula (1) according to the present invention will be described in detail.

In the general formula (1), R ₁ , R ₂ , R ₃ and R ₄ represent a hydrogen atom or a substituent. The substituent represented by R ₁ , R ₂ , R ₃ and R ₄ is not particularly limited, and examples thereof include alkyl groups (for example, methyl group, ethyl group, propyl group, isopropyl group, tert-butyl group, pentyl group). Hexyl group, octyl group, dodecyl group, trifluoromethyl group, etc.), cycloalkyl group (eg, cyclopentyl group, cyclohexyl group etc.), aryl group (eg, phenyl group, naphthyl group etc.), acylamino group (eg, acetyl group) Amino group, benzoylamino group, etc.), alkylthio group (eg, methylthio group, ethylthio group, etc.), arylthio group (eg, phenylthio group, naphthylthio group, etc.), alkenyl group (eg, 2-propenyl group, 3-butenyl group, etc.) 1-methyl-3-propenyl group, 3-pentenyl group, 1-methyl-3-butenyl group, 4-hexenyl Group, cyclohexenyl group, etc.), halogen atom (fluorine atom, chlorine atom, bromine atom, iodine atom etc.), alkynyl group (eg propargyl group etc.), heterocyclic group (eg pyridyl group, thiazolyl group, oxazolyl group) , Imidazolyl group, etc.), alkylsulfonyl group (eg, methylsulfonyl group, ethylsulfonyl group, etc.), arylsulfonyl group (eg, phenylsulfonyl group, naphthylsulfonyl group, etc.), alkylsulfinyl group (eg, methylsulfinyl group, etc.), Arylsulfinyl group (eg, phenylsulfinyl group), phosphono group, acyl group (acetyl group, pivaloyl group, benzoyl group, etc.), carbamoyl group (eg, aminocarbonyl group, methylaminocarbonyl group, dimethylaminocarbonyl group, butylamino) Carboni Group, cyclohexylaminocarbonyl group, phenylaminocarbonyl group, 2-pyridylaminocarbonyl group, etc.), sulfamoyl group (for example, aminosulfonyl group, methylaminosulfonyl group, dimethylaminosulfonyl group, butylaminosulfonyl group, hexylaminosulfonyl group, cyclohexyl) Aminosulfonyl group, octylaminosulfonyl group, dodecylaminosulfonyl group, phenylaminosulfonyl group, naphthylaminosulfonyl group, 2-pyridylaminosulfonyl group, etc.), sulfonamide groups (for example, methanesulfonamide group, benzenesulfonamide group, etc.), cyano Group, alkoxy group (for example, methoxy group, ethoxy group, propoxy group, etc.), aryloxy group (for example, phenoxy group, naphthyloxy group, etc.), heterocyclic oxy , Siloxy group, acyloxy group (for example, acetyloxy group, benzoyloxy group, etc.), sulfonic acid group, sulfonic acid salt, aminocarbonyloxy group, amino group (for example, amino group, ethylamino group, dimethylamino group, butyl) Amino group, cyclopentylamino group, 2-ethylhexylamino group, dodecylamino group, etc.), anilino group (for example, phenylamino group, chlorophenylamino group, toluidino group, anisidino group, naphthylamino group, 2-pyridylamino group, etc.), imide Group, ureido group (for example, methylureido group, ethylureido group, pentylureido group, cyclohexylureido group, octylureido group, dodecylureido group, phenylureido group, naphthylureido group, 2-pyridylaminoureido group, etc.), alkoxycarbonyl Ruamino group (for example, methoxycarbonylamino group, benzenesulfonamide group, etc.), alkoxycarbonyl group (for example, methoxycarbonyl group, ethoxycarbonyl group, phenoxycarbonyl, etc.), aryloxycarbonyl group (for example, phenoxycarbonyl group, etc.), heterocyclic ring Examples thereof include thio group, thioureido group, carboxyl group, carboxylic acid salt, hydroxyl group, mercapto group, nitro group and the like.

  These substituents may be further substituted with the same substituent.

R ₁ and R ₂ are preferably an alkyl group, a cycloalkyl group, an aryl group, a heterocyclic group, an alkoxy group, an aryloxy group, an amino group, an anilino group, an alkylthio group and an arylthio group, and an alkyl group, an aryl group, a heterocyclic group A cyclic group, an alkoxy group, an aryloxy group, an amino group, and an anilino group are more preferable.

R ₃ and R ₄ are preferably a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group, a heterocyclic group, an alkoxy group, an aryloxy group, an amino group, an anilino group, an alkylthio group, and an arylthio group. Group, cycloalkyl group, aryl group and heterocyclic group are more preferred, and a hydrogen atom is most preferred.

  In the general formula (1), X includes a group having active hydrogen such as a hydroxyl group, an amino group, a sulfonic acid group, a carboxyl group, an alkylsulfonamino group, and a thiol group, and particularly preferably a hydroxyl group. .

Y represents O, S or NR ₅ (R ₅ is a hydrogen atom or a substituent), and particularly preferably O. The substituent represented by R ₅ is not particularly limited as long as it is a substituent bonded to the N atom, and examples of the substituent include the same groups as R ₁ described above.

  In the general formula (1), A represents the general formula (2) or (3).

In the general formula (2), X ₁ forms a 5- or 6-membered monocyclic aromatic heterocyclic ring or a condensed aromatic heterocyclic ring together with the carbon atom bonded to the ethylene group and the nitrogen atom bonded to the carbon atom. Represents an atomic group necessary for. Specific examples of the aromatic heterocycle include pyridine ring, pyrazole ring, imidazole ring, pyrazine ring, pyrimidine ring, pyridazine ring, triazine ring, thiazole ring, isothiazole ring, thiadiazole, oxazole ring, isoxazole ring, oxadiazole Examples thereof include a ring, a triazole ring, a tetrazole ring, a quinoline ring, an isoquinoline ring, a benzothiazole ring, a benzoisothiazole ring, a benzoxazole ring, a benzoisoxazole ring, a benzopyrazole ring, and a benzimidazole ring. A pyridine ring, a pyrazole ring, an imidazole ring, a thiadiazole ring, an oxazole ring, an isoxazole ring, and a triazole ring are preferable. These rings may have a substituent, and examples of the substituent include the same groups as the above R _1, and may be further substituted with the same substituent.

In the general formula (3), X ₂ is a 5- to 6-membered monocyclic aromatic carbocycle or aromatic heterocycle together with a carbon atom bonded to an ethylene group and a carbon atom containing a substituent G bonded to the carbon atom. A group of atoms necessary for forming a ring or a condensed aromatic carbocyclic ring or aromatic heterocyclic ring. Specific examples of the aromatic carbocycle or aromatic heterocycle include benzene ring, naphthalene ring, pyridine ring, pyrrole ring, pyrazole ring, imidazole ring, pyrazine ring, pyrimidine ring, pyridazine ring, thiazole ring, isothiazole ring, thiadiazole , Oxazole ring, isoxazole ring, oxadiazole ring, triazole ring, quinoline ring, isoquinoline ring, indole ring and the like. A benzene ring is preferred. These rings may have a substituent, and examples of the substituent include the same groups as the above R _1, and may be further substituted with the same substituent.

G represents a chelatable group, for example, hydroxyl group, alkoxy group, aryloxy group, mercapto group, alkylthio group, arylthio group, amino group, anilino group, alkoxycarbonyl group, acyloxy group, sulfamoyl group, sulfonamide group, Examples thereof include a carbamoyl group, an amide group, and a carboxy group. Preferred are a hydroxyl group, an alkoxy group, and an amino group. G may combine with X ₂ to form a ring, and for example, may form a ring such as a quinoline ring, a tetrahydroquinoline ring, a chroman ring, a thiochroman ring, a benzoquinazolone ring, or a benzothiadiazine ring. These rings may have a substituent, and examples of the substituent include the same groups as the above R _1, and may be further substituted with the same substituent.

Atoms necessary for forming a 5- to 6-membered monocyclic aromatic heterocyclic ring or a condensed aromatic heterocyclic ring together with the carbon atom bonded to the azo group represented by X ₁ and the nitrogen atom bonded to the carbon atom A 5- to 6-membered monocyclic aromatic carbocycle or aromatic heterocycle together with the carbon atom comprising the group, and the carbon atom bonded to the azo group represented by X ₂ and the substituent G bonded to the carbon atom Examples of the atomic group necessary for forming a condensed aromatic carbocycle or aromatic heterocycle include those represented by the following general formula, but the present invention is not limited thereto. . Moreover, these may have the same substituent as said R < ₁ >.

  The metal chelate compound having the compound represented by the general formula (1) as a ligand is preferably represented by the following general formula (4).

In the formula, M represents a metal ion, L represents an anion, m represents an integer of 1 to 3, and n represents an integer of 0 to 3. _{R 1, R 2, R 3} , R 4, X, Y and A have the same meanings as _{R 1, R 2, R 3} , R 4, X, Y and A in the general formula (1), A represents the Represents general formula (2) or (3).

  In the general formula (4), the metal ion represented by M is selected from the group VIII, Ib, IIb, IIIa, IVa, Va, VIa, and VIIa metal atoms, preferably 2 It is a valent transition metal ion. Specific examples include divalent metal ions of Ni, Cu, Co, Cr, Zn, Fe, Pd, and Pt, and more preferable examples include divalent metal ions of Ni, Cu, Co, and Zn. Ni divalent metal ions are preferred.

In the general formula (4), examples of the anion represented by L include enolate (acetylacetonate, hexafluoroacetylacetonate), halogen ion (fluoride, chloride, bromide, iodide, etc.), hydroxide ion, sulfurous acid. Ion, sulfate ion, alkyl sulfonate ion, aryl sulfonate ion, nitrate ion, nitrite ion, carbonate ion, perchlorate ion, alkyl carboxylate ion, aryl carboxylate ion, tetraalkylborate, salicinate, benzoate, PF _{6 ^{-, BF 4 -, SbF 6}} - and the like are.

  The compound represented by the general formula (1) may be bonded at an arbitrary position to form a multimer. In this case, each unit may be the same as or different from each other, and polystyrene, polymethacrylate, You may couple | bond with polymer chains, such as polyvinyl alcohol and a cellulose.

  The metal chelate compound having the compound represented by the general formula (1) used in the optical information recording medium of the present invention as a ligand may be used alone or in a different structure. You may mix and use multiple types. Further, the content of the metal chelate compound having the compound represented by the general formula (1) in the present invention in the recording layer as a ligand is preferably 30 to 100% by mass with respect to the dry mass of the entire recording layer. 60-100 mass% is still more preferable, and 90-100 mass% is the most preferable.

  Further, in the recording layer of the present invention, a dye that can be used in a conventional optical information recording medium within a range that does not affect the effects of the present invention and a compound represented by the general formula (1) in the present invention are arranged. You may use together with the metal chelate compound made into a ligand. In addition to the recording layer, a light reflecting layer made of metal is provided. Further, a protective layer is provided separately from the recording layer. The substrate is a transparent disk-like substrate on which a pregroove with a track pitch of 0.2 to 0.5 μm is formed, and the recording layer is preferably provided on the surface on the side where the pregroove is formed. .

  Specific examples of the compound represented by the general formula (1) and the metal chelate compound represented by the general formula (4) are shown below, but the present invention is not limited to the following specific examples.

  The compound used in the present invention can be easily synthesized by the synthesis method described in Tetrahedron Letter 35, Vol. 7, No. 1047-1050 (1994).

In the present invention, the metal ion-containing compound includes inorganic or organic salts of metal ions and metal complexes. As a metal ion, the metal ion similar to the metal ion in the said General formula (4) can be mentioned. Specific examples include divalent metal ions of Ni, Cu, Co, Cr, Zn, Fe, Pd, and Pt, and more preferable examples include divalent metal ions of Ni, Cu, Co, and Zn. Ni divalent metal ions are preferred. Inorganic salts include metal salts such as Cl ⁻ , ClO ₄ ⁻ , PF ₆ ⁻ , and BF ₄ ⁻ , and organic salts include aliphatic and metal salts such as acetic acid, stearic acid, and 2-ethylhexanoic acid. And salts of aromatic carboxylic acids such as benzoic acid, salicylic acid, and tosylic acid with metals. Moreover, as a metal complex, the metal source represented by following General formula (5) can be used.

General formula (5) [M (P1) _m1 (P2) _m2 (P3) _m3 ] ⁺ _r (Y2 ⁻ ) _r
In the formula, M represents a metal ion, and P1, P2, and P3 each represent a coordination compound that can coordinately bond with the metal ion represented by M, and may be the same or different from each other. These coordination compounds can be selected from, for example, coordination compounds described in Chelate Science (5) (Nan Edo). Y 2 ⁻ represents an organic anion group, and specific examples thereof include a tetraphenyl boron anion and an alkylbenzene sulfonate anion. m1 represents an integer of 1, 2 or 3, m2 represents 1, 2 or 0, and m3 represents 1 or 0. In these, the complex represented by the above general formula is tetradentate or hexadentate. Depending on the number of ligands of P1, P2 and P3. r represents 0, 1 or 2; r = 0 means that the coordination compound represented by P is an anionic compound, and the anionic compound represented by P and the metal cation represented by M are electrically neutralized. To do.

  As the anionic compound, a compound represented by the following general formula (6) is preferable.

R ₁₁ and R ₁₃ each represents an alkyl group or an aryl group which may be the same or different, and R ₁₂ represents an alkyl group, an alkoxy group, a halogen atom, an alkoxycarbonyl group or a hydrogen atom. R ₁₁ , R ₁₂ and R ₁₃ may be substituted with the same substituent as the substituent represented by R ₁ .

  Although the specific example of the said metal ion containing compound is given to the following, this invention is not limited to these.

  There is no limitation on the mixing ratio (molar ratio) of at least one compound represented by the general formula (1) and the mixture of the metal ion-containing compound, and the compound represented by the general formula (1): metal When ion-containing compound = 1: X, X represents 0.01 or more, preferably 0.1 or more, more preferably 0.5 or more.

  The mixture is prepared by adding a metal ion-containing compound powder or a solution dissolved in an organic solvent to a solution obtained by dissolving or dispersing the compound represented by the general formula (1) in an organic solvent. The mixture may be isolated as crystals, and when isolation is difficult, the solvent may be distilled off and the residue may be used, or the residue may be further dissolved in another solvent and used. .

  The optical information recording medium of the present invention has a recording layer containing a metal chelate compound having the compound represented by the general formula (1) as a ligand on a substrate. The optical information recording medium of the present invention includes a variety of configurations. The optical information recording medium of the present invention has a configuration in which a recording layer, a light reflecting layer and a protective layer are arranged in this order on a disc-like substrate on which pregrooves having a constant track pitch are formed, or a light reflecting layer and a recording layer on the substrate. A structure having a layer and a protective layer in this order is preferable. In addition, two laminated bodies in which a recording layer and a light reflection layer are provided on a transparent disk-shaped substrate on which pregrooves having a constant track pitch are formed are bonded so that each recording layer is inside. The configuration is also preferable.

  The optical information recording medium of the present invention can use a substrate on which a pre-groove having a narrower track pitch is formed as compared with CD-R and DVD-R in order to achieve higher recording density. In the case of the optical information recording medium of the present invention, the track pitch is preferably in the range of 0.2 to 0.8 μm, more preferably in the range of 0.2 to 0.5 μm, particularly 0.2 to 0.5 μm. It is preferably in the range of 0.4 μm. The depth of the pregroove is preferably in the range of 0.01 to 0.18 μm, more preferably in the range of 0.01 to 0.15 μm, and particularly in the range of 0.02 to 0.15 μm. Is preferred. The width between adjacent pregrooves is preferably in the range of 0.05 to 0.4 μm, more preferably in the range of 0.08 to 0.3 μm, particularly in the range of 0.1 to 0.25 μm. Preferably there is.

  As an example of the optical information recording medium of the present invention, a manufacturing method having a recording layer, a light reflecting layer, and a protective layer in this order on a disc-like substrate will be described below.

  The substrate of the optical information recording medium of the present invention can be arbitrarily selected from various materials used as a substrate of a conventional optical information recording medium. Examples of substrate materials include acrylic resins such as glass, polycarbonate, and polymethyl methacrylate, vinyl chloride resins such as polyvinyl chloride and vinyl chloride copolymers, epoxy resins, amorphous polyolefins, and polyesters. You may use them together. Note that these materials can be used as a film or as a rigid substrate. Among the above materials, polycarbonate is preferable from the viewpoint of moisture resistance, dimensional stability, price, and the like.

  An undercoat layer may be provided on the surface of the substrate on which the recording layer is provided for the purpose of improving the flatness, improving the adhesive force, and preventing the recording layer from being altered. Examples of the material for the undercoat layer include polymethyl methacrylate, acrylic acid / methacrylic acid copolymer, styrene / maleic anhydride copolymer, polyvinyl alcohol, N-methylol acrylamide, styrene / vinyl toluene copolymer, chlorosulfone. Polymer materials such as chlorinated polyethylene, nitrocellulose, polyvinyl chloride, chlorinated polyolefin, polyester, polyimide, vinyl acetate / vinyl chloride copolymer, ethylene / vinyl acetate copolymer, polyethylene, polypropylene, polycarbonate; and silane coupling And a surface modifier such as an agent. The undercoat layer is formed by dissolving or dispersing the above substances in an appropriate solvent to prepare a coating solution, and then applying this coating solution to the substrate surface by a coating method such as spin coating, dip coating, or extrusion coating. can do. The thickness of the undercoat layer is generally in the range of 0.005 to 20 μm, preferably in the range of 0.01 to 10 μm.

  The recording layer can be formed by a method such as vapor deposition, sputtering, CVD or solvent coating, and among these, solvent coating is preferred. In this case, the dye compound, and further, if desired, a quencher, a binder, etc. are dissolved in a solvent to prepare a coating solution, and then the coating solution is applied to the substrate surface to form a coating film, followed by drying. It can be carried out. Examples of the solvent for the coating solution include esters such as butyl acetate, ethyl lactate and cellosolve acetate; ketones such as methyl ethyl ketone, cyclohexanone and methyl isobutyl ketone; chlorinated hydrocarbons such as dichloromethane, 1,2-dichloroethane and chloroform; dimethylformamide and the like Amides; Hydrocarbons such as methylcyclohexane; Ethers such as dibutyl ether, diethyl ether, tetrahydrofuran, dioxane; Alcohols such as ethanol, n-propanol, isopropanol, n-butanol, diacetone alcohol; 2,2,3,3-tetra Fluorinated solvents such as fluoropropanol; ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, propylene glycol monomethyl ether, etc. And the like can be mentioned recall ethers. The above solvents can be used alone or in combination of two or more in consideration of the solubility of the dye used. Various additives such as an antioxidant, a UV absorber, a plasticizer, and a lubricant may be further added to the coating solution depending on the purpose.

  In the case of using a binder, examples of the binder include natural organic polymer materials such as gelatin, cellulose derivatives, dextran, rosin and rubber; and hydrocarbon resins such as polyethylene, polypropylene, polystyrene and polyisobutylene, poly Vinyl resins such as vinyl chloride, polyvinylidene chloride, polyvinyl chloride / polyvinyl acetate copolymer, acrylic resins such as polymethyl acrylate and polymethyl methacrylate, polyvinyl alcohol, chlorinated polyethylene, epoxy resin, butyral resin, Examples include synthetic organic polymers such as rubber derivatives and initial condensates of thermosetting resins such as phenol / formaldehyde resins. When a binder is used in combination as a material for the recording layer, the amount of binder used is generally in the range of 0.01 to 50 times (mass ratio), preferably 0.1 to 5 times the amount of the dye (mass ratio). (Mass ratio). Thus, the density | concentration of the pigment | dye in the coating liquid prepared is in the range of 0.01-10 mass% generally, Preferably it exists in the range of 0.1-5 mass%.

  Examples of the coating method include a spray method, a spin coating method, a dip method, a roll coating method, a blade coating method, a doctor roll method, and a screen printing method. The recording layer may be a single layer or a multilayer. The thickness of the recording layer is generally in the range of 0.01 to 0.5 μm, preferably in the range of 0.015 to 0.3 μm, and more preferably in the range of 0.02 to 0.1 μm.

  The recording layer can contain various anti-fading agents in order to improve the light resistance of the recording layer. As the anti-fading agent, a singlet oxygen quencher is generally used. As the singlet oxygen quencher, those described in publications such as known patent specifications can be used. Specific examples thereof include JP-A Nos. 58-175893, 59-81194, 60-18387, 60-19586, 60-19586, 60-35054, 60-36190, 60-36191, 60-44554, 60-44555, 60-44389, 60-44390, 60-54892, 60-47069, 63-20995, JP 4-25492, JP-B-1-38680, and 6-26028, etc., German Patent No. 350,399, and Japanese Chemical Society Journal October 1992, page 1141, etc. Can be mentioned. As an example of a preferable singlet oxygen quencher, a compound represented by the following general formula (7) can be given.

However, R ²¹ represents an alkyl group which may have a substituent, and Q ^- represents an anion. In the general formula (7), R ²¹ is generally an optionally substituted alkyl group having 1 to 8 carbon atoms, and is preferably an unsubstituted alkyl group having 1 to 6 carbon atoms. Examples of the substituent of the alkyl group include a halogen atom (eg, F, Cl), an alkoxy group (eg, methoxy, ethoxy), an alkylthio group (eg, methylthio, ethylthio), an acyl group (eg, acetyl, propionyl), an acyloxy group (Eg, acetoxy, propionyloxy), hydroxy group, alkoxycarbonyl group (eg, methoxycarbonyl, ethoxycarbonyl), alkenyl group (eg, vinyl), and aryl group (eg, phenyl, naphthyl). Among these, a halogen atom, an alkoxy group, an alkylthio group, and an alkoxycarbonyl group are preferable. Preferred examples of the Q ⁻ anion include ClO ₄ ⁻ , AsF ₆ ⁻ , BF ₄ ⁻ , and SbF ₆ ⁻ .

  Examples of the compound represented by the general formula (7) are described below.

  The amount of the antifading agent such as the singlet oxygen quencher used is relative to the amount of the compound (including the metal chelate compound having the compound represented by the general formula (1) in the present invention as a ligand). Usually, it is the range of 0.1-50 mass%, Preferably it is the range of 0.5-45 mass%, More preferably, it is the range of 1-40 mass%, Most preferably, it is the range of 2-25 mass%.

  It is preferable to provide a light reflection layer adjacent to the recording layer for the purpose of improving reflectivity during information reproduction. The light-reflecting substance that is the material of the light-reflecting layer is a substance having a high reflectance with respect to laser light. Examples thereof include Mg, Se, Y, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Mn, Re, Fe, Co, Ni, Ru, Rh, Pd, Ir, Pt, Cu, Ag, Au, Zn, Cd, Al, Ga, In, Si, Ge, Te, Pb, Po, Sn, Mention may be made of metals such as Bi and metalloids or stainless steel. These substances may be used alone or in combination of two or more or as an alloy. Among these, Cr, Ni, Pt, Cu, Ag, Au, Al, and stainless steel are preferable. Particularly preferred are Au metal, Ag metal, Al metal or alloys thereof, and most preferred are Ag metal, Al metal or alloys thereof. The light reflecting layer can be formed on the substrate or the recording layer, for example, by vapor deposition, sputtering or ion plating of the light reflecting material. The thickness of the light reflecting layer is generally in the range of 0.01 to 0.3 μm, and preferably in the range of 0.05 to 0.2 μm.

A protective layer is preferably provided on the light reflecting layer or the recording layer for the purpose of physically and chemically protecting the recording layer and the like. In the case of adopting the same form as that for manufacturing a DVD-R type optical information recording medium, that is, a structure in which two substrates are laminated with the recording layer inside, the protective layer is not necessarily provided. Examples of materials used for the protective layer include inorganic substances such as Zn—SiO ₂ , ZnS, SiO, SiO ₂ , MgF ₂ , SnO ₂ , Si ₃ N ₄ , thermoplastic resins, thermosetting resins, and UV curable resins. Organic substances such as resins can be mentioned. The protective layer can be formed, for example, by laminating a film obtained by extrusion of plastic on the reflective layer through an adhesive. Or you may provide by methods, such as vacuum evaporation, sputtering, and application | coating. In the case of a thermoplastic resin or a thermosetting resin, it can also be formed by dissolving these in a suitable solvent to prepare a coating solution, and then applying and drying the coating solution. In the case of a UV curable resin, it can also be formed by preparing a coating solution as it is or by dissolving it in a suitable solvent, coating the coating solution, and curing it by irradiating with UV light. In these coating liquids, various additives such as an antistatic agent, an antioxidant, and a UV absorber may be added according to the purpose. The thickness of the protective layer is generally in the range of 0.1 μm to 1 mm. Through the above steps, it is possible to produce a laminate in which a recording layer, a light reflecting layer and a protective layer are provided on a substrate, or a light reflecting layer, a recording layer and a protective layer are provided on a substrate.

  The information recording method of the present invention is performed, for example, as follows using the optical information recording medium. First, recording light such as semiconductor laser light is irradiated from the substrate side or the protective layer side while rotating the optical information recording medium at a constant linear velocity (3.84 m / second in the case of DVD-R format) or a constant angular velocity. To do. By this light irradiation, the recording layer absorbs the light and the temperature rises locally, causing a physical or chemical change (for example, generation of pits) and changing its optical characteristics, thereby recording information. It is thought that it is done. In the present invention, semiconductor laser light having an oscillation wavelength in the range of 390 to 430 nm is used as recording light. As a preferable light source, a blue-violet semiconductor laser beam having an oscillation wavelength in the range of 400 to 410 nm, an infrared semiconductor laser beam having a central oscillation wavelength of 850 nm or 820 nm, and a central oscillation wavelength obtained by halving the wavelength using an optical waveguide element are each 425 nm. Alternatively, a 410 nm blue-violet SHG laser beam can be used. In particular, it is preferable to use blue-violet semiconductor laser light in terms of recording density. The information recorded as described above is reproduced by irradiating a semiconductor laser beam from the substrate side or the protective layer side while rotating the optical information recording medium at the same constant linear velocity as above and detecting the reflected light. Can be done by.

  EXAMPLES Next, although an Example demonstrates this invention further in detail, this invention is not limited to a following example.

Example 1
Exemplified Compound 4-1 was dissolved in 2,2,3,3-tetrafluoropropanol to obtain a recording layer forming coating solution (concentration: 1% by mass). A polycarbonate substrate (diameter: 120 mm, thickness) on which a spiral pre-groove (track pitch: 0.4 μm, groove width: 0.2 μm, groove depth: 0.05 μm) is formed by injection molding on the surface of this coating solution. The recording layer (thickness (inside the pregroove): about 80 nm) was formed on the surface of the pregroove side having a thickness of 0.6 mm by spin coating.

  Next, silver was sputtered on the recording layer to form a light reflecting layer having a thickness of about 100 nm. Further, a UV curable resin (SD318, manufactured by Dainippon Ink & Chemicals, Inc.) was applied on the light reflecting layer and cured by irradiating with ultraviolet rays to form a protective layer having a layer thickness of 7 μm.

  The optical information recording medium (optical disk) of the present invention was obtained by the above process.

Examples 2-4
The optical information recording medium of the present invention was produced in the same manner as in Example 1, except that the exemplified compound 4-1 was changed to the compounds shown in Table 1 (the amount used was not changed).

Comparative Examples 1-4
In the same manner as in Example 1, except that Exemplified Compound 4-1 was changed to Comparative Dye Compounds (A) to (D) shown below (the amount used was unchanged), an optical information recording medium for comparison ( Optical disc).

[Evaluation as optical information recording medium (optical disc)]
A 14T-EFM signal was recorded on the optical disk produced above at a linear velocity of 3.5 m / sec using a blue-violet semiconductor laser beam having an oscillation wavelength of 405 nm, and the recorded signal was reproduced. The modulation degree, groove reflectance, and sensitivity at the optimum power were measured. Recording and recording characteristic evaluation were performed using DDU1000 manufactured by Pulstec Industrial Co., Ltd. The evaluation results are shown in Table 1.

<Comparative dye compound>
(A): Compound described in Example 1 of JP-A-4-74690

  (B): Compound described in Example 1 of JP-A-11-334205

  (C): Compound described in Example 9 of JP-A-2000-43423

  (D): Specific example 1-1 described in Example 9 of Japanese Patent Laid-Open No. 2000-149320

From the results in Table 1, a recording layer containing a compound represented by the general formula (4) according to the present invention and a mixture of at least one of the compounds represented by the general formula (1) and a metal ion-containing compound. The optical discs (Examples 1 to 4 ) having the above are compared with the blue-violet semiconductor laser light as compared with the optical discs (Comparative Examples 1 to 4) having recording layers containing the comparative dye compounds (A) to (D). It can be seen that it exhibits high reflectivity, provides a high degree of modulation, and is highly sensitive. That is, it can be seen that an optical disc having high recording characteristics with respect to a short wavelength laser beam can be obtained.

Claims (3)

An optical information recording medium comprising a recording layer capable of recording information by laser beam irradiation, containing at least one metal chelate compound having a compound represented by the following general formula (1) as a ligand.

(In the formula, A represents the following general formula (2) or (3), X represents a group having active hydrogen, Y represents O, S, NR ₅ , R ₁ , R ₂ , R ₃ , R ₄ and R ₅ each independently represents a hydrogen atom or a substituent.)

(Wherein X ₁ is necessary to form a 5- or 6-membered monocyclic aromatic heterocyclic ring or condensed aromatic heterocyclic ring together with a carbon atom bonded to the azo group and a nitrogen atom bonded to the carbon atom. Represents an atomic group, and these aromatic heterocycles may have a substituent.)

(In the formula, X ₂ is a 5- to 6-membered monocyclic aromatic carbocycle or aromatic heterocycle together with a carbon atom containing a carbon atom bonded to an azo group and a substituent G bonded to the carbon atom, or Represents a group of atoms necessary to form a fused aromatic carbocyclic ring or aromatic heterocyclic ring, and these aromatic carbocyclic rings or aromatic heterocyclic rings may further have a substituent, and G can be chelated. And G may combine with X ₂ to form a ring.) The optical information recording medium according to claim 1, wherein the laser light irradiation is selected from a range of wavelengths of 390 to 430 nm. 3. An information recording method comprising recording information by irradiating the optical information recording medium according to claim 1 or 2 with a laser beam selected from a wavelength range of 390 to 430 nm .