JP3776201B2 - Optical recording medium - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a recording medium, and in particular, by irradiating a light beam, optical changes such as transmittance and reflectance of a recording material are caused, information is recorded and reproduced, and additional recording is performed. The present invention relates to a possible optical recording medium.
[0002]
[Prior art]
In the current write-once optical disc system (WORM, CD-R), the oscillation wavelength of the laser used is in the range of 770 nm to 790 nm, and the recording medium is configured to be able to record and reproduce at the above wavelength. In the future, it is essential to increase the capacity of recording media as the amount of information increases. Therefore, it is easily expected that the laser wavelength used for recording and reproduction will inevitably become shorter.
In addition, many proposals have been made to use a cyanine dye or a phthalocyanine dye as a recording material as a write-once optical disk for data (for example, those using a cyanine dye as a recording material are disclosed in JP-A-57-82093). JP-A-58-56892, JP-A-58-12790, JP-A-58-114989, JP-A-59-85791, JP-A-60-83236, JP-A-60-89842, JP-A-61-25886, etc., and those using phthalocyanine dyes as recording materials include JP-A-61-150243, JP-A-61-177287, JP-A-61-154888, JP-A-61-246091, JP-A-62-39286, JP-A-63-37791, JP-A-63-39888, etc.) Excellent storage stability, and recorded in an optical pickup using the following laser 700 nm, the reproduction is possible recording materials, at present, not been developed yet.
[0003]
The current CD-R disc system is also configured to be able to record and reproduce at the oscillation wavelength of the laser used, 770 nm to 790 nm. In this system as well, it is essential to increase the capacity and shorten the recording / reproducing wavelength. In this regard, current CDs and CD-ROMs are coated with Al on the unevenness of the substrate itself, and the wavelength dependence of the reflectance of Al is small. Therefore, even if the laser wavelength is shortened in the future, reproduction will not be possible. Is possible.
However, CD-R uses a dye having a maximum absorption wavelength at 680 nm to 750 nm for the recording layer, and is set so as to obtain a high reflectance from 770 nm to 790 nm from its optical constant and film thickness configuration. Reflectance is extremely low in the wavelength range, and it is impossible to cope with the shortening of the laser wavelength, and information recorded and reproduced by the current CD-R system cannot be reproduced by a future system. Many proposals using a cyanine dye / metal reflective layer, a phthalocyanine dye / metal reflective layer, or an azo metal chelate dye / metal reflective layer as a recording material have been made as CD-Rs (for example, cyanine dye / metal). In the case of using a reflective layer as a recording material, JP-A-1-159842, JP-A-2-42652, JP-A-2-13656, JP-A-2-168446, etc. use a phthalocyanine dye as a recording material. Those used are JP-A-1-176585, JP-A-3-215466, JP-A-4-113886, JP-A-4-226390, JP-A-5-1272, JP-A-5-171052, and JP-A-5-171052. JP-A-5-116456, JP-A-5-69860, JP-A-5-139044, and the like, and azo metal chelate dyes as recording materials Are disclosed in Japanese Patent Laid-Open No. 4-46186, Japanese Patent Laid-Open No. 4-14189, Japanese Patent Laid-Open No. 4-361888, Japanese Patent Laid-Open No. 5-279580, etc.). Nothing has been found yet.
[0004]
[Problems to be solved by the invention]
Accordingly, the present invention has been made in view of the above situation, and is light-resistant and storage applicable to a high-density optical disk system using a semiconductor laser having an oscillation wavelength shorter than that of the conventional system. Providing recording materials for optical recording media with excellent stability, as well as recording materials for CD-R media that can be recorded and reproduced with the current system and can be reproduced with the next-generation high-density optical disc system It is intended.
[0005]
[Means for Solving the Problems]
As a result of intensive studies, the present inventors have found that by providing a recording layer mainly composed of a dye having a specific structure, the present invention can be applied to a high-density optical disk system using a semiconductor laser having an oscillation wavelength of 700 nm or less. Furthermore, it has been found that by using this dye mixed with an organic dye currently used as a recording material for CD-R, it is possible to obtain a high reflectance even in a wavelength region of 700 nm or less. The invention has been completed.
[0006]
  That is, according to the present invention, firstly, in an optical recording medium in which a recording layer is provided directly on a substrate or via an undercoat layer, and further, if necessary, a reflective layer and a protective layer are provided thereon. In the recording layer, the following general formulas (I) to (IIIAnd an optical recording medium comprising at least one compound represented by formula (1).
[Chemical 1]
[Chemical formula 2]
[Chemical Formula 3]
[In the formula, R¹~ R⁷1, m, n, Z, X, and Q each represent the following.
R¹~ R^Three: Each independently an amino group, an optionally substituted dialkylamino group having 1 to 6 carbon atoms, a halogen atom, a nitro group, a hydroxyl group, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxy group, substituted or unsubstituted A substituted alkylthio group, a substituted or unsubstituted carboxylic acid ester group, a substituted or unsubstituted aryl group, a substituted or unsubstituted aryloxy group, or a substituted or unsubstituted arylthio group,
R^Four~ R⁶: Each independently a halogen atom, a nitro group, a hydroxyl group, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted alkylthio group, a substituted or unsubstituted dialkylamino group, O^-, COO^-Or SO_Three ^-,
l, m: each independently an integer of 0-3,
n: an integer from 0 to 4,
R⁷: Halogen atom, nitro group, hydroxyl group, substituted or unsubstituted alkyl group, substituted or unsubstituted alkoxy group, substituted or unsubstituted alkylthio group, amino group, dialkylamino group, O^-, COO^-Or SO_Three ^- ,
Z: a heterocyclic residue,
X: acid anion or metal complex anion,
Q: 0 or 1. ]
Second, the recording layer has the general formulas (I) to (III1) and an organic dye having a maximum absorption wavelength at 680 nm to 750 nm. The optical recording medium described in the first item is provided. Thirdly, there is provided the optical recording medium described in the second aspect, wherein the organic dye having the maximum absorption wavelength at 680 nm to 750 nm is at least one of pentamethine cyanine dye, phthalocyanine dye and azo metal chelate dye. Fourthly, there is provided the optical recording medium according to any one of the first to third aspects, wherein the recording layer is recorded by a laser beam having a wavelength of 630 to 720 nm. Fifth, the optical recording medium according to any one of the first to fourth aspects, wherein the reflective layer is made of aluminum or gold. Sixth, the optical recording medium described in any one of the first to fifth is provided, wherein the protective layer is made of an ultraviolet curable resin.
[0007]
  The optical recording medium of the present invention comprises the above general formulas (I) to (III), A recording layer containing at least one of the compounds represented by (1) can be recorded and reproduced with a laser beam having a wavelength of 700 nm or less, and has excellent light resistance and storage stability. In another embodiment, the general formulas (I) to (III) And a recording layer made of a mixture of an organic dye having a maximum absorption wavelength at 680 to 750 nm is provided, so that it can be used as a CD-R medium in the current system, and the next generation. Even with the high-density optical disc system, it is possible to reproduce the described information.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
  The present invention will be described in detail below. The optical recording medium of the present invention has the following general formulas (I) to (IIIIt contains at least one kind of the compound represented by
[Chemical 1]
[Chemical formula 2]
[Chemical Formula 3]
[0009]
  First, the above general formula (I), (II), (III)When the compound shown by said is demonstrated, said general formula (I)-(III), R¹, R², R^ThreeAre each independently an amino group, an optionally substituted dialkylamino group having 1 to 6 carbon atoms, a halogen atom, a nitro group, a hydroxyl group, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxy group, substituted or Represents an unsubstituted alkylthio group, a substituted or unsubstituted carboxylic acid ester group, a substituted or unsubstituted aryl group, a substituted or unsubstituted aryloxy group, or a substituted or unsubstituted arylthio group;^Four, R^Five, R⁶Each independently represents a halogen atom, a nitro group, a hydroxyl group, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted alkylthio group, a substituted or unsubstituted dialkylamino group, O^-, COO^-Or SO_Three ^-Represents. l and m each independently represent an integer of 0 to 3, and n represents an integer of 0 to 4. R⁷Is a halogen atom, nitro group, hydroxyl group, substituted or unsubstituted alkyl group, substituted or unsubstituted alkoxy group, substituted or unsubstituted alkylthio group, amino group, dialkylamino group, O^-, COO^-Or SO_Three ^-Represents,Z represents a heterocyclic residue. X represents an acid anion or a metal complex anion, and Q represents 0 or 1.
[0010]
X is a halogen ion, a perhalogenate ion, an alkyl sulfate anion, PF₆Anion, BF_FourAnion, SbF₆Represents an acid anion such as an anion, R¹, R², R^ThreeWhen the number of alkyl carbon atoms of the dialkylamino group is 6 or more, the stability (light resistance, storage stability) is extremely lowered.
[0011]
  Formulas (I) to (IIIR in¹~ R⁷Specific examples of the alkyl group (including an alkyl group in an alkoxy group, an alkylalkoxy group, and a carboxylate group) include
Methyl group, ethyl group, n-propyl group, n-butyl group, isobutyl group, n-pentyl group, neopentyl group, isoamyl group, 2-methylbutyl group, n-hexyl group, 2-methylpentyl group, 3-methylpentyl Group, 4-methylpentyl group, 2-ethylbutyl group, n-heptyl group, 2-methylhexyl group, 3-methylhexyl group, 4-methylhexyl group, 5-methylhexyl group, 2-ethylpentyl group, 3- Ethylpentyl group, n-octyl group, 2-methylheptyl group, 3-methylheptyl group, 4-methylheptyl group, 5-methylheptyl group, 2-ethylhexyl group, 3-ethylhexyl group, n-nonyl group, n- Primary alkyl group such as decyl group, n-dodecyl group; isopropyl group, sec-butyl group, 1-ethylpropyl group, 1-methylbutyl group, , 2-dimethylpropyl group, 1-methylheptyl group, 1-ethylbutyl group, 1,3-dimethylbutyl group, 1,2-dimethylbutyl group, 1-ethyl-2-methylpropyl group, 1-methylhexyl group, 1-ethylheptyl group, 1-propylbutyl group, 1-isopropyl-2-methylpropyl group, 1-ethyl-2-methylbutyl group, 1-propyl-2-methylpropyl group, 1-methylheptyl group, 1-ethylhexyl Group, 1-propylpentyl group, 1-isopropylpentyl group, 1-isopropyl-2-methylbutyl group, 1-isopropyl-3-methylbutyl group, 1-methyloctyl group, 1-ethylheptyl group, 1-propylhexyl group, Secondary alkyl groups such as 1-isobutyl-3-methylbutyl group; tert-butyl group, tert-hexyl group, Tertiary alkyl groups such as ert-amyl group and tert-octyl group; cyclohexyl group, 4-methylcyclohexyl group, 4-ethylcyclohexyl group, 4-tert-butylcyclohexyl group, 4- (2-ethylhexyl) cyclohexyl group, bornyl Group, cycloalkyl group such as isobornyl group, adamantane group and the like, and these alkyl groups may be substituted with a substituent such as halogen atom.
[0012]
Specific examples of the substituted or unsubstituted aryl group (including the aryl part of the substituted or unsubstituted aryloxy group) include phenyl group, methylphenyl group, dimethylphenyl group, trimethylphenyl group, ethylphenyl group, tert. -Butylphenyl group, butylphenyl group, nonylphenyl group, methoxyphenyl group, dimethoxyphenyl group, butoxyphenyl group, naphthyl group, pyridyl group, methylpyridyl group and the like can be mentioned. These aryl groups may be substituted with a substituent such as a halogen atom.
[0013]
Z represents a heterocyclic residue, and specific examples thereof include a substituted or unsubstituted pyridine residue, pyridazine residue, pyrimidine residue, pyrazine residue, and thiophene residue.
[0014]
Q is 0 or 1, but R^FourOr R⁷Is O^-, COO^-, SO_Three ^-Q is 0 only in any of the cases, and 1 in all other cases.
[0015]
Specific examples of the metal complex anion in X include the following.
[Chemical formula 5]
Where R¹¹, R¹²Represents a hydrogen atom, a substituted or unsubstituted alkyl group, an aryl group, or a heterocyclic residue. M represents Ni, Pd, Pt, Cu or Co.
[Chemical 6]
Where R¹¹, R¹², R¹³, R¹⁴Represents a hydrogen atom, a halogen atom, an alkyl group, an aryl group, a cycloalkyl group, or a heterocyclic residue bonded directly or indirectly through a divalent linking group. M is the same as described above.
[Chemical 7]
Where X¹Is S or CR¹¹R¹²Represents. R¹¹, R¹²CN, COR¹³, COOR¹⁴, CONR¹⁵R¹⁶Or SOR¹⁷Represents an atomic group necessary to form a 5-membered ring or a 6-membered ring, and R¹³~ R¹⁷Represents a substituted or unsubstituted alkyl group or an aryl group. M is the same as described above.
[0016]
[Chemical 8]
Where R¹¹, R¹², R¹³, R¹⁴Represents a hydrogen atom, a halogen atom, an alkyl group, an aryl group, a cycloalkyl group, or a heterocyclic residue bonded directly or indirectly through a divalent linking group. R¹⁵Represents a hydrogen atom, an alkyl group, an aryl group, an acyl group, a carboxyl group, or a sulfonyl group. M is the same as described above.
[Chemical 9]
Where R¹¹, R¹², R¹³, R¹⁴Represents a hydrogen atom, a halogen atom, an alkyl group, an aryl group, a cycloalkyl group, or a heterocyclic residue bonded directly or indirectly through a divalent linking group. R¹⁵, R¹⁶Represents a hydrogen atom, an alkyl group, an aryl group, an acyl group, a carboxyl group, or a sulfonyl group. M is the same as described above.
Embedded image
Where R¹¹, R¹²Represents a hydrogen atom, an alkyl group, or an aryl group. R¹³, R¹⁴, R¹⁵, R¹⁶Represents a hydrogen atom, a halogen atom, an alkyl group, or an aryl group. M is the same as described above.
[0017]
Embedded image
Where X¹Represents O or S. R¹¹, R¹², R¹³Represents a substituted or unsubstituted alkyl group, aryl group, or cycloalkyl group bonded directly via an oxy group, a thio group, or an amino group. M is the same as described above.
Embedded image
Where R¹¹, R¹², R¹³Represents a substituted or unsubstituted alkyl group, aryl group, or cycloalkyl group bonded directly or via an oxy group, a thio group, or an amino group. X¹Represents O or S. R¹⁴Represents an alkyl group or an aryl group. M is the same as described above.
Embedded image
Where R¹¹, R¹²Represents a hydrogen atom, a substituted or unsubstituted alkyl group, an aryl group, or a heterocyclic residue. M is the same as described above.
[0018]
Embedded image
Where R¹¹, R¹², R¹³, R¹⁴Represents a hydrogen atom, a halogen atom, an alkyl group, an aryl group, a cycloalkyl group, or a heterocyclic residue bonded directly or indirectly through a divalent linking group. M is the same as described above.
Embedded image
Where R¹¹, R¹², R¹³, R¹⁴Represents a hydrogen atom, a halogen atom, an alkyl group, an aryl group, a cycloalkyl group, or a heterocyclic residue bonded directly or indirectly through a divalent linking group. R¹⁵, R¹⁶Represents a hydrogen atom, an alkyl group, an aryl group, an acyl group, a carboxyl group, or a sulfonyl group. M is the same as described above.
Embedded image
Where R¹¹Represents an alkyl group or an aryl group. R¹², R¹³, R¹⁴, R¹⁵Represents a hydrogen atom, a halogen atom, an alkyl group, or an aryl group. M is the same as described above.
[0019]
Examples of compounds of metal complex anions are shown in Table 1.
[0020]
[Table 1- (1)]
[0021]
[Table 1- (2)]
[0022]
  The general formulas (I) to (IIIAs specific examples of the compounds represented by), for example, Table 2- (1) to Table 2- (2) Are listed.
[0023]
[Table 2- (1)]
[0024]
[Table 2- (2)]
[0026]
  In the recording layer, as described above, the general formulas (I) to (I)III) And the organic dye having the maximum absorption wavelength at 680 to 750 nm as a main component, recording and reproduction can be performed with the current system, and reproduction can also be performed with the next generation system. Is a possible CD-R recording medium. As the dye having the maximum absorption wavelength at 680 to 750 nm in this case, a pentamethine cyanine dye, a phthalocyanine dye and an azo metal chelate dye are preferable.
[0027]
Preferable examples of the pentamethine cyanine dye include those represented by the following general formula (V).
Embedded image
Where R^{twenty one}, R^{twenty two}Is an alkyl group having 1 to 3 carbon atoms, R^{twenty three}, R^{twenty four}Is a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, X²Represents an acid anion. The aromatic ring may be condensed with other aromatic rings, and may be substituted with an alkyl group, a halogen atom, an alkoxy group or an acyl group.
[0028]
Preferable examples of the phthalocyanine dye include those represented by the following general formula (VI-1) or (VI-2).
Embedded image
Where M¹Represents Ni, Pd, Cu, Zn, Co, Mn, Fe, TiO or VO, X^Five~ X⁸Each independently represents —OR or —SR at the substituted position α, R represents an optionally substituted linear, branched or alicyclic alkyl group having 3 to 12 carbon atoms or an optionally substituted aryl group. Represents. X^Five~ X⁸The substituent on the benzene ring other than is a hydrogen atom or a halogen atom.
[0029]
Embedded image
Where M²Is Si, Ge, In, or Sn, X⁹~ X¹²Each independently represents —OR or —SR at the substituted position α, R represents an optionally substituted linear, branched or alicyclic alkyl group having 3 to 12 carbon atoms or an optionally substituted aryl group. Y^Five, Y⁶Is -OSiR^{twenty five}R²⁶R²⁷, -OCOR^{twenty five}R²⁶R²⁷Or -OPOR^{twenty five}R²⁶R²⁷Represents R^{twenty five}~ R²⁷Each independently represents an alkyl or aryl group having 1 to 10 carbon atoms. X⁹~ X¹²The substituent of the benzene ring other than is a hydrogen atom or a halogen atom.
[0030]
Further, preferred examples of the azo metal chelate dye include one or more azo metal chelate compounds of an azo compound and a metal represented by the following general formula (VII). Preferred examples of the metal include , Ni, Pt, Pd, Co, Cu, Zn and the like.
Embedded image
Wherein A represents a residue that forms a heterocycle with the carbon and nitrogen atoms to which it is attached, and B represents an aromatic ring with the two carbon atoms to which it is attached. Or a residue that forms a heterocyclic ring, and X^ThreeRepresents a group having active hydrogen.
[0031]
  The general formulas (I) to (I) of the present inventionIII) And at least one dye represented by the above general formulas (V) to (VII) are used in a weight composition ratio of the present dye / [(V) to (VII ) Dye] = 10/100 to 90/100, preferably 40/100 to 20/100. Further, when both dyes are used in combination, the thickness of the recording layer is 500 to 5 μm, preferably 1000 to 5000 mm.
[0032]
Next, the configuration of the recording medium of the present invention will be described.
FIG. 1 is a diagram showing an example of a layer structure applicable to the recording medium of the present invention, which is an example of a write-once type optical disc. A recording layer 2 is provided on the substrate 1 via an undercoat layer 3 as necessary, and a protective layer 4 is further provided as necessary. Further, a hard coat layer can be provided under the substrate 1 as necessary.
FIG. 2 is a diagram showing another example of a layer structure applicable to the recording medium of the present invention, which is an example of CD-R media. A reflective layer 6 is provided on the recording layer 2 having the configuration shown in FIG.
The recording medium of the present invention may have an air sandwich structure in which the recording layer (organic thin film layer) having the configuration shown in FIGS. 1 and 2 is placed inside and sealed with another substrate through a space. A laminated structure bonded via a protective layer may be used.
[0033]
Next, the required characteristics of the constituent layers and the constituent materials will be described.
1) Substrate
As a necessary characteristic of the substrate, when recording / reproducing is performed from the substrate side, it must be transparent to the laser beam used. However, when recording / reproducing is performed from the recording layer side, it is not necessary to be transparent. As the substrate material, for example, polyester, acrylic resin, polyamide, polycarbonate resin, polyolefin resin, phenol resin, epoxy resin, polyimide or other plastic, glass, ceramic, metal, or the like can be used. A tracking guide groove or guide pit and a preformat such as an address signal may be formed on the surface of the substrate.
[0034]
2) Recording layer
The recording layer is capable of causing some optical change upon irradiation with a laser beam and recording information by the change. In the recording layer, at least one of the compounds represented by the general formulas (I) to (III) is contained. It is necessary that at least one of the dyes represented by the general formulas (IV) to (VI) is further contained. Furthermore, these dyes can of course be mixed or laminated with other organic dyes, metals, and metal compounds in order to improve optical characteristics, recording sensitivity, and signal characteristics. Other organic dyes in this case include polymethine dyes, naphthalocyanine series, phthalocyanine series, squarylium series, croconium series, pyrylium series, naphthoquinone series, anthraquinone (indanthrene) series, xanthene series, triphenylmethane series, and azulene series. , Tetrahydrocholine-based, phenanthrene-based, triphenothiazine-based dyes, metal complex compounds, and the like. Examples of metals and metal compounds include In, Te, Bi, Se, Sb, Ge, Sn, Al, Be, TeO.₂, SnO, As, Cd, etc., each of which can be used in the form of dispersion mixing or lamination. In addition, various materials such as ionomer resins, polyamide resins, vinyl resins, natural polymers, silicones, liquid rubbers, or silane coupling agents may be dispersed and mixed in the dyes. For the purpose of improvement, it can be used together with a stabilizer (for example, a transition metal complex), a dispersant, a flame retardant, a lubricant, an antistatic agent, a surfactant, a plasticizer and the like.
[0035]
The recording layer can be formed by ordinary means such as vapor deposition, sputtering, CVD or solvent coating. When using the coating method, the above-mentioned dye or the like can be dissolved in an organic solvent, and a conventional coating method such as spraying, roller coating, dipping or spin coating can be used. As the organic solvent used, alcohols such as methanol, ethanol and isopropanol, ketones such as acetone, methyl ethyl ketone and cyclohexanone, amides such as N, N-dimethylacetamide and N, N-dimethylformamide, and sulfoxides such as dimethyl sulfoxide are generally used. Ethers such as tetrahydrofuran, dioxane, diethyl ether and ethylene glycol monomethyl ether, esters such as methyl acetate and ethyl acetate, aliphatic halogenated carbons such as chloroform, methylene chloride, dichloroethane, carbon tetrachloride and trichloroethane, benzene , Aromatics such as xylene, monochlorobenzene and dichlorobenzene, or cellsolves such as methoxyethanol and ethoxyethanol, hexane, Tan, cyclohexane, and hydrocarbons such as methylcyclohexane.
The film thickness of the recording layer is 100 to 10 μm, preferably 200 to 2000 μm.
[0036]
3) Undercoat layer
The undercoat layer is: (1) improved adhesion, (2) barrier against water or gas, (3) improved storage stability of recording layer, (4) improved reflectivity, (5) substrate from solvent And (6) guide grooves, guide pits, preformats, etc. For the purpose of (1), polymer materials such as ionomer resins, polyamides, vinyl resins, natural resins, natural polymers, silicones, liquid rubbers, various polymer compounds and silane coupling agents are used. For the purposes of (2) and (3), in addition to the above polymer materials, inorganic compounds such as SiO₂, MgF₂, SiO, TiO₂, ZnO, TiN, SiN, and the like, and metal or semimetal such as Zn, Cu, Ni, Cr, Ge, Se, Au, Ag, and Al can be used. For the purpose of (4), metals such as Al, Au and Ag, and organic thin films having metallic luster such as methine dyes and xanthene dyes can be used. (5) and (6) For the purpose of ▼, an ultraviolet curable resin, a thermosetting resin, a thermoplastic resin, or the like can be used. The thickness of the undercoat layer is 0.01 to 30 μm, preferably 0.05 to 10 μm.
[0037]
4) Reflective layer
The reflective layer can be made of a metal or semimetal that is highly resistant to corrosion and is not easily corroded. Examples of materials include Au, Ag, Al, Cr, Ni, Fe, and Sn. Au and Al are most preferable from the viewpoint of reflectivity and productivity. These metals and metalloids may be used alone or in combination of two or more. Examples of the film forming method include vapor deposition and sputtering, and the film thickness is 50 to 5000 mm, preferably 100 to 3000 mm.
[0038]
5) Protective layer, substrate surface hard coat layer
The protective layer or the substrate hard coat layer (1) protects the recording layer (reflection / absorption layer) from scratches, dust, dirt, etc., (2) improves the storage stability of the recording layer (reflection / absorption layer), and (3) ▼ Used for the purpose of improving reflectivity. For these purposes, the materials shown for the undercoat layer can be used. Also, inorganic materials such as SiO and SiO₂Can also be used, such as polymethyl acrylate, polycarbonate, epoxy resin, polystyrene, polyester resin, vinyl resin, cellulose, aliphatic hydrocarbon resin, natural rubber, styrene-butadiene resin, chloroprene rubber, wax, alkyd resin Also, heat softening and heat melting resins such as drying oil and rosin can be used. The most preferable among the above materials is an ultraviolet curable resin excellent in productivity. The film thickness of the protective layer or the substrate surface hard coat layer is 0.01 to 30 μm, preferably 0.05 to 10 μm.
[0039]
In the present invention, the undercoat layer, the protective layer, and the substrate surface hard coat layer, as in the recording layer, include a stabilizer, a dispersant, a flame retardant, a lubricant, an antistatic agent, a surfactant, a plasticizer, and the like. Can be contained.
[0040]
【Example】
Hereinafter, the present invention will be described with reference to examples, but the present invention is not limited thereto.
[0041]
Example 1
Example 1
On a substrate in which a guide groove having a depth of 1200 mm, a half width of 0.4 μm, and a track pitch of 1.4 μm is formed by a photopolymer on a polymethyl methacrylate substrate having a thickness of 1.2 μm, the compound specific example No. The 1,2-dichloroethane solution of No. 1 was spinner coated to provide a recording layer having a thickness of 800 mm to obtain a recording medium.
[0042]
Examples 2-8
In Example 1, compound specific examples No. In place of compound No. 1 2, no. 6, no. 13, no. 17, no. 19, no. 22, no. Recording media of Examples 2 to 8 were obtained in the same manner as Example 1 except that 24 was used.
[0043]
Comparative Example 1
In Example 1, compound specific examples No. A recording medium of Comparative Example 1 was obtained in the same manner as Example 1 except that the compound represented by the following formula (VIII) was used instead of 1.
Embedded image
[0044]
Using the recording media of Examples 1 to 8 and Comparative Example 1 described above, light was incident from the substrate under the following recording conditions for recording, and then the C / N and reflectance were measured at the recording position with reproduction light. The results are shown in Table 3.
[0045]
[Table 3]
[0046]
Example 9
On a 1.2 mm thick injection-molded polycarbonate substrate having a guide groove with a depth of 1000 mm, a half width of 0.4 μm, and a track pitch of 1.6 μm, compound specific example No. A solution prepared by dissolving 8 in a mixed solution of methylcyclohexane, 2-methoxyethanol, methyl ethyl ketone, and tetrahydrofuran was applied by a spinner to form a recording layer having a thickness of 1800 mm, and then a reflective layer having a thickness of 2000 mm was formed thereon by sputtering. Further, a protective layer having a thickness of 5 μm was provided thereon with an acrylic photopolymer to obtain a recording medium.
[0047]
Example 10, 11, 12, 15, and 16
  In Example 9, compound specific examples No. In place of Compound No. 8, Compound Specific Example No. 3, no. 5, no. 26,No. 16, no. Example 10 was carried out in the same manner as Example 9 except that 21 was used., 11, 12, 15, and 16Recording medium was obtained.
[0048]
Comparative Example 2
In Example 9, compound specific examples No. A recording medium of Comparative Example 2 was obtained in the same manner as Example 9, except that the compound represented by the formula (VIII) used in Comparative Example 1 was used instead of 8.
[0049]
  Example 910, 11, 12, 15 and 16In addition, a semiconductor laser beam having an oscillation wavelength of 680 nm and a beam diameter of 1.4 μm is used for the recording medium of Comparative Example 2, and an EFM signal is recorded while tracking (linear velocity: 1.4 m / sec) and reproduced by continuous light of the same laser ( (Examples 15 and 16 were reproduced at an oscillation wavelength of 635 nm), and the reproduced waveform was observed. The results are shown in Table 4.
[0050]
[Table 4]
[0051]
Example 17
A compound represented by the following formula (IX) and a compound specific example No. 1 were formed on an injection-molded polycarbonate substrate having a depth of 1000 mm, a half width of 0.45 μm, and a guide groove having a track pitch of 1.6 μm and a thickness of 1.2 mm. 11 is dissolved in a mixed solvent of methylcyclohexane, 2-methoxyethanol, methyl ethyl ketone, and tetrahydrofuran in a weight ratio (1/1) and spinner coated to form a recording layer having a thickness of 1700 mm. A 2000-mm reflective layer was formed, and a protective layer of 5 μm was further formed thereon with an acrylic photopolymer to obtain a recording medium.
[0052]
Embedded image
[0053]
Example 18
  In Example 17, the compound specific examples No. In place of Compound No. 11, Compound Specific Example No. 7TheExample 18 was carried out in the same manner as Example 17 except that it was used.ofA recording medium was obtained.
[0055]
Embedded image
[0056]
Example 23
  In Example 17, the compound specific examples No. Specific compound instead of 11ExampleNo. Example 2 was carried out in the same manner as in Example 17 except that compound 14 was used and a compound represented by the following formula (XI) was used instead of the compound represented by the above formula (IX).3Recording medium was obtained.
[0057]
Embedded image
[0058]
Comparative Examples 3-5
In Example 17, except that the recording layer was only the compound represented by the general formula (IX), only the compound represented by the general formula (X), and only the compound represented by the general formula (XI). In the same manner as in Example 17, the recording media of Comparative Examples 3 to 5 were obtained.
[0059]
  Example 17, 18,23 and the recording media of Comparative Examples 3 to 5 were recorded by using a semiconductor laser beam having an oscillation wavelength of 780 nm and a beam diameter of 1.6 μm, and recording an EFM signal while tracking (linear velocity: 1.4 m / sec). Reproduction was performed with continuous light from a semiconductor laser having a beam diameter of 1.4 μm at 680 nm (however, only Example 23 was carried out at a reproduction oscillation wavelength of 635 nm), and the reproduction waveform was observed. The results are shown in Table 5.
[0060]
[Table 5]
[0061]
【The invention's effect】
  The optical recording medium according to claim 1 has the general formulas (I) to (III), The recording layer contains at least one compound, and therefore has a high light absorption ability and light reflectivity at a wavelength of 700 nm or less, so that high-density recording is possible at 700 nm. Recording and reproduction can be performed with a laser beam having the following wavelength range, and excellent in light resistance and storage stability.
[0062]
  The optical recording medium of claim 2 is characterized in that the general formulas (I) to (I)III) And an organic dye having a maximum absorption wavelength at 680 to 750 nm in the recording layer, so that recording and reproduction can be performed with the current system, and the next generation. Even in a high-density optical disc system, recorded information can be reproduced.
[0063]
In the optical recording medium according to claim 3, since at least one of cyanine dye, phthalocyanine dye and azo metal chelate dye of pentamethine is selected as the organic dye having the maximum absorption wavelength at 680 to 750 nm, high quality signal characteristics are recorded. It becomes possible.
[0064]
In the optical recording medium of claim 4, since the recording layer is recorded by a laser beam having a wavelength of 630 to 720 nm, the density is increased by 1.6 to 1.8 times as compared with the optical recording medium corresponding to 770 to 830 nm. A write-once optical recording medium is obtained.
[0065]
In the optical recording medium according to the fifth aspect, since the reflective layer is made of aluminum or gold, high reflectance and CD-R media with good productivity can be achieved.
[0066]
In the optical information recording medium according to the sixth aspect, since the protective layer is made of an ultraviolet curable resin, it is possible to form a protective layer with high productivity.
[Brief description of the drawings]
FIG. 1 is a diagram showing an example of a layer structure as a normal write-once type optical recording medium that can be applied to the recording medium of the present invention.
FIG. 2 is a diagram showing an example of a layer structure for CD-R that can be applied to the recording medium of the present invention.
[Explanation of symbols]
1 Substrate
2 Recording layer (organic dye layer)
3 Underlayer
4 Protective layer
5 Hard coat layer
6 Reflective layer

Claims (6)

In an optical recording medium in which a recording layer is provided directly on a substrate or via an undercoat layer, and further, if necessary, a reflective layer and a protective layer are provided, the following general formula (I) is contained in the recording layer: An optical recording medium comprising at least one of the compounds represented by ( III ).
[Wherein R ^{1 to} R ⁷ , 1, m, n, Z, X, and Q each represent the following.
R ^{1 to} R ³ : each independently an amino group, an optionally substituted dialkylamino group having 1 to 6 carbon atoms, a halogen atom, a nitro group, a hydroxyl group, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxy A group, a substituted or unsubstituted alkylthio group, a substituted or unsubstituted carboxylic acid ester group, a substituted or unsubstituted aryl group, a substituted or unsubstituted aryloxy group, or a substituted or unsubstituted arylthio group,
R ^{4 to} R ⁶ : each independently a halogen atom, nitro group, hydroxyl group, substituted or unsubstituted alkyl group, substituted or unsubstituted alkoxy group, substituted or unsubstituted alkylthio group, substituted or unsubstituted dialkylamino group, O ⁻ , COO ⁻ , or SO ₃ ⁻ ,
l, m: each independently an integer of 0-3,
n: an integer from 0 to 4,
R ⁷ : halogen atom, nitro group, hydroxyl group, substituted or unsubstituted alkyl group, substituted or unsubstituted alkoxy group, substituted or unsubstituted alkylthio group, amino group, dialkylamino group, O ⁻ , COO ⁻ , or SO ₃ ^-,
Z: a heterocyclic residue,
X: acid anion or metal complex anion,
Q: 0 or 1. ] 2. The recording layer according to claim 1, wherein the recording layer contains at least one compound represented by the general formulas (I) to ( III ) and an organic dye having a maximum absorption wavelength at 680 nm to 750 nm. Optical recording media.   3. The optical recording medium according to claim 2, wherein the organic dye having the maximum absorption wavelength at 680 nm to 750 nm is at least one of a pentamethine cyanine dye, a phthalocyanine dye, and an azo metal chelate dye.   The optical recording medium according to claim 1, wherein the recording layer is recorded by laser light having a wavelength of 630 to 720 nm.   The optical recording medium according to claim 1, wherein the reflective layer is made of aluminum or gold.   The optical recording medium according to claim 1, wherein the protective layer is made of an ultraviolet curable resin.