JP2002293031A - Optical recording medium and optical recording / reproducing method using the optical recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a recording material for an optical recording medium having excellent light resistance and storage stability applicable to a high-density optical disc system using a semiconductor laser having an oscillation wavelength shorter than a conventional system. And a recording material for a CD-R medium that can be recorded and reproduced by the current system and can be reproduced by the next-generation high-density optical disk system. SOLUTION: In an optical recording medium having at least a recording layer provided directly or via an undercoat layer on a substrate, the recording layer is formed of a compound represented by the following structural formula (I) and / or (II) and a metal compound. An optical recording medium comprising a layer containing at least one coordination compound. Embedded image Embedded image

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-density optical recording medium using a recording material capable of recording and reproducing at a wavelength of 700 nm or less.

[0002]

2. Description of the Related Art As an optical recording medium having a reflective layer on a substrate, a recordable CD (CD-R) compliant with the compact disk (CD) standard has been commercialized. Wavelength 7 on recording layer
The recording layer is irradiated with a laser beam of 70 to 830 nm to cause a physical or chemical change in the recording layer, and the reflected light is detected to record and reproduce information. Recently, the development of semiconductor lasers having shorter wavelengths has been advanced, and red semiconductor lasers having wavelengths of 630 to 685 nm have been put to practical use. Optical recording media have been produced. Current write-once optical disc systems (WORM, CD-R)
The oscillation wavelength of the laser used is in the range of 770 to 790 nm, and the optical recording medium is set so that recording and reproduction can be performed at the above wavelength. In the future, as the amount of information increases, it is essential to increase the capacity of recording media. Therefore, it is easily expected that the wavelength of the laser used for recording and reproduction will be shortened. However, at present, a recording material which is excellent in light resistance and storage stability and can be recorded and reproduced by an optical pickup using a laser of 700 nm or less has not yet been developed. The current CD-R disk system has a laser oscillation wavelength of 770 to 790 nm.
Thus, recording and reproduction can be performed. Similarly, in this system, it is essential to increase the capacity and shorten the recording and reproducing wavelengths. In current CDs and CD-ROMs, Al is coated on the unevenness of the substrate itself, and the wavelength dependence of the reflectance of Al is small, so that reproduction is possible even if the laser wavelength is shortened in the future. . However, CD
For -R, a dye having a maximum absorption wavelength at 680 to 750 nm is used for the recording layer.
Since the reflectivity is set so as to be as high as about 790 nm, the reflectivity is extremely low in a wavelength region of 700 nm or less, and it is impossible to cope with the shortening of the laser wavelength.
-Information recorded and reproduced by the R system cannot be reproduced by a future system.

[0003]

SUMMARY OF THE INVENTION The present invention is directed to an optical recording system having excellent light resistance and storage stability applicable to a high-density optical disk system using a semiconductor laser having an oscillation wavelength in a short wavelength as compared with the conventional system. It is an object of the present invention to provide a recording material for a medium, and a recording material for a CD-R medium which can be recorded and reproduced by a current system and can be reproduced in a next-generation high-density optical disk system. In addition, the present invention has higher solubility in an organic solvent applicable to a high-density optical disc system using a blue semiconductor laser having an oscillation wavelength in a shorter wavelength than the above DVD system, and has excellent light resistance and storage stability. A recording material for a recording medium, and a recording material for a DVD-R recording medium that can be recorded and reproduced by a current DVD system and can be reproduced only in a next-generation high-density optical disc system;
And a recording / reproducing method using the recording material.

[0004]

Means for Solving the Problems The inventors of the present invention have made intensive studies on the means for solving the above-mentioned problems, and as a result, by using a recording layer containing a specific azo metal chelate dye as a main component, an oscillation wavelength of 700 nm or less was obtained. Is found to be applicable to a high-density optical disc system using a semiconductor laser of the present invention, and furthermore, the compound of the present invention is mixed with an organic dye used as a recording material for the current CD-R, so that recording and reproduction can be performed with the current system. The present inventors have found that reproduction is possible even with the high-density laser light, and have reached the present invention.

The organic dye compound used in the recording layer of the optical recording medium of the present invention includes a coordination compound of a compound represented by the following structural formula (I) and / or (II) and a metal compound.

Embedded image (Wherein X ₁ , X ₂ , X ₃ , and X ₄ represent a hydrogen atom, a halogen atom, a nitro group, a sulfonamide group, an alkyl group or an alkoxy group having 1 to 5 carbon atoms, and X ₁ , X ₂ , X
₃ and X ₄ may be the same or different. R ₁ and R ₂ each independently represent a hydrogen atom, an alkyl group having 1 to 8 carbon atoms or an aryl group which may have a substituent. )

Embedded image [In the formula, X ₁ , X ₂ , X ₃ and X ₄ represent a hydrogen atom, a halogen atom, a nitro group, a sulfonamide group, an alkyl group or an alkoxy group having 1 to 5 carbon atoms, and X ₁ , X ₂ , X
₃ and X ₄ may be the same or different. Y ₁ , Y ₂ , Y ₃ , Y ₄ , Y ₅ and Y _{6 each} represent a hydrogen atom,
An alkyl group having 1 to 8 carbon atoms which may have a substituent,
An aryl group which may have a substituent, an amino group, an alkylamino group which may have a substituent, an acetyl group,
Represents an acetylamino group, a hydroxy group or a carboxyl group, which may be the same or different; A, B are each independently, -OH, -OCH _3,
—NH ₂ , —SH, —NHR ₃ (R ₃ has 1 to 3 carbon atoms.
A lower alkyl group) or -COOH. ]

As a general method for synthesizing these compounds, an aniline derivative may be diazotized by adding sodium nitrite in the presence of an acid, and an N, N'-dialkylaniline derivative may be added thereto for coupling. . Next, the metal coordination compound can be obtained by adding the metal compound to the obtained monoazo dye in a solvent such as water or ethylene glycol and heating and stirring the compound. Examples of the coordinable metal compound include copper, silver, gold, nickel, palladium, zinc, chromium, masogane, iron, cobalt, ruthenium, rhodium, iridium, platinum, molybdenum, and organic inorganic salt compounds such as tungsten. Preferably chromium, iron,
Cobalt, nickel, zinc and copper compounds. As the configuration of the optical recording medium of the present invention, the structure of a write-once optical disc shown in FIG. 1 (a so-called air sandwich structure in which two sheets of FIG. 1 are bonded, or a close bonding structure) may be used. A high reflectivity structure (a CD-R structure or a close bonding structure) may be used, or a structure in which a recording layer is provided between two substrates shown in FIG. 3 (a DVD-R structure).

Hereinafter, the configuration of the optical recording medium of the present invention and its constituent members will be described in detail. <Recording Layer> The recording layer causes some optical change by irradiation with a laser beam and records information by the change. In this recording layer, the structural formula (I) or ( It is necessary to contain at least one kind of coordination compound (dye) of the compound represented by II) and a metal compound, and a combination of two or more kinds may be used in forming the recording layer. Furthermore, the above-mentioned coordination compound (dye) of the present invention may be used by mixing or laminating with another organic dye, a metal, or a metal compound for the purpose of improving optical characteristics, recording sensitivity, signal characteristics, and the like. Examples of other organic dyes include polymethine dyes, naphthalocyanine dyes, phthalocyanine dyes, squarylium dyes, croconium dyes, pyrylium dyes, naphthoquinone dyes, anthraquinone dyes (indanthrene dyes), xanthene dyes, triphenylmethane dyes, and azulene dyes. , Tetrahydrocholine-based, phenanthrene-based, triphenothiazine-based dyes, and metal complex compounds. Examples of metals and metal compounds include In, T
e, Bi, Se, Sb, Ge, Sn, Al, Be, Te
O ₂ , SnO, As, Cd and the like can be mentioned, and each of them can be used in the form of dispersion mixing or lamination.

In particular, the coordination compound (dye) of the present invention and 6
By mixing a dye having a maximum absorption wavelength in the range of 80 nm to 750 nm, a DVD-R medium that can be recorded and reproduced by a current DVD system and can be reproduced by a blue laser can be formed. 680 nm to 750 n
As the dye having the maximum absorption wavelength at m, a dye usable for DVD-R can be used as it is. In addition, various materials such as ionomer resins, polyamides, vinyl resins, natural polymers, silicones, liquid rubbers and the like, or silane coupling agents may be dispersed and mixed in the above-mentioned dyes to improve the properties. (For example, a transition metal complex), a dispersant, a flame retardant, a lubricant, an antistatic agent, a surfactant, a plasticizer, and the like may be used together for the purpose of.

The recording layer is formed by vapor deposition, sputtering,
It can be carried out by ordinary means such as CVD or solvent application. When using the coating method, the above dyes and the like are dissolved in an organic solvent, and spray, roller coating,
It can be performed by a conventional coating method such as dipping and spin coating. As the organic solvent used, methanol, ethanol, alcohols such as isopropanol, acetone, methyl ethyl ketone,
Ketones such as cyclohexanone, amides such as N, N-dimethylformamide and N, N-dimethylacetamide, sulfoxides such as dimethyl sulfoxide, ethers such as tetrahydrofuran, dioxane, diethyl ether, ethylene glycol monomethyl ether, methyl acetate; Esters such as ethyl acetate, chloroform, methylene chloride, dichloroethane, carbon tetrachloride,
Aliphatic halogenated hydrocarbons such as trichloroethane,
Examples include aromatics such as benzene, xylene, monochlorobenzene, and dichlorobenzene; cellosolves such as methoxyethanol and ethoxyethanol; and hydrocarbons such as hexane, pentane, cyclohexane, and methylcyclohexane. The thickness of the recording layer is 100 to
10 μm, preferably 200 to 2000 °, is suitable.

Next, as specific compounds corresponding to the general formulas (I) and (II) used in the present invention, the following compound Nos. 1 to 32 and 41 to 68 are shown. However, the compounds used in the present invention are not limited to these.

Embedded image

[0011]

[Table 1]

[0012]

[Table 2]

[0013]

[Table 3]

[0014]

[Table 4]

[0015]

[Table 5]

[0016]

[Table 6]

[0017]

[Table 7]

[0018]

[Table 8]

[0019]

Embedded image

[0020]

[Table 9]

[0021]

[Table 10]

[0022]

[Table 11]

[0023]

[Table 12]

[0024]

[Table 13]

[0025]

[Table 14]

Preferred dyes having a maximum absorption wavelength at 680 to 750 nm mixed with at least one of the above coordination compounds (dyes) include the following i-iii. i. Cyanine dye represented by the following formula (1)

Embedded image (Wherein, R ₅ and R ₆ : alkyl groups having 1 to 3 carbon atoms. R ₇ , R ₈ : alkyl groups having 1 to 6 carbon atoms which may have a substituent. X: acid anion. The benzene ring may be condensed with another aromatic ring, and may be substituted with an alkyl group, a halogen, an alkoxy group, or an acyl group.)

Ii. Phthalocyanine dye represented by the following formula (2) or (3)

Embedded image (Wherein, M ₁ : Ni, Pd, Cu, Zn, Co, Mn,
Fe, TiO, VO. X _{5 to} X ₈ : -OR at the α-position, -S
R or a hydrogen atom, but not all hydrogen atoms. R: a linear alkyl group having 3 to 12 carbon atoms which may have a substituent, a branched alkyl group which may have a substituent,
A cycloalkyl group optionally having a substituent or an aryl group optionally having a substituent; The benzene ring may have a substituent other than X _{5 to} X ₈ , and in that case, the substituent of the benzene ring is hydrogen or halogen. )

[0028]

Embedded image (Wherein, M ₂ represents Si, Ge, In, or Sn. X _{9 to} X ₁₂ are —OR, —SR, or a hydrogen atom at the α-position, and not all of them are hydrogen atoms. R Is the same as the above (2) Y ₃ , Y ₄ : —OSiRaRbRc, —OCORa, —
OPORaRb. Ra, Rb, Rc: an alkyl group having 1 to 10 carbon atoms and an aryl group. The benzene ring may have a substituent other than the above X _{9 to} X ₁₂ , and in that case, the substituent of the benzene ring is hydrogen or halogen. )

Iii. Azo metal chelate compound One or more azo metal chelate compounds of an azo compound represented by the following formula (4) and a metal, and preferable examples of the metal include Ni, Pt, Pd, Co, Cu, and Zn. And the like.

Embedded image Wherein A represents a residue that forms a heterocycle together with the carbon and nitrogen atoms to which it is attached, and B represents an aromatic group that is taken together with the two carbon atoms to which it is attached. Represents a residue forming an aromatic ring or a heterocyclic ring, and X represents a group having active hydrogen.)

The coordination compound (dye) of the present invention and 680 nm
The mixing ratio (weight ratio) with the dye having the maximum absorption wavelength at 750 nm is the former: the latter = 10: 100 to 90:10.
0, preferably 40: 100 to 20: 100, and the thickness of the recording layer is 500 ° to 5 μm, preferably 1000 to 100 μm.
5000 °.

<Substrate> The substrate is transparent to the laser used only when recording and reproduction are performed from the substrate side, and need not be transparent when recording and reproduction are performed from the recording layer side. As a substrate material, plastic such as polyester, acrylic resin, polyamide, polycarbonate, polyolefin, phenol resin, epoxy resin, and polyimide, glass, ceramic, and metal can be used. Note that a guide groove or guide pit for tracking, and a preformat such as an address signal may be formed on the surface of the substrate.

<Undercoat Layer> The undercoat layer comprises (a) an improvement in adhesiveness, (b) a barrier against water or gas, (c) an improvement in storage stability of the recording layer, and (d) an improvement in reflectance. , (E) protection of the substrate from solvents, and (f) formation of guide grooves, guide pits, preformats, and the like. (A)
For the purpose of (1), various polymer substances such as ionomer resins, polyamides, vinyl resins, natural resins, natural polymers, silicones, liquid rubbers, and silane coupling agents can be used, and (b) For the purposes of (c) and (c), in addition to the polymer material, SiO ₂ , MgF ₂ , S
inorganic compounds such as iO, TiO ₂ , ZnO, TiN, SiN, Zn, Cu, Ni, Cr, Ge, Se, Au, A
Metals or metalloids such as g and Al can be used. In addition, for the purpose of (d), an organic thin film having a metallic luster such as a metal such as Al or Ag or a methine dye or a xanthene dye can be used, and for the purposes of (e) and (f), For example, an ultraviolet curing resin, a thermosetting resin, a thermoplastic resin, or the like can be used. The thickness of the undercoat layer is 0.01 to
It is 30 μm, preferably 0.05 to 10 μm.

<Metal Reflective Layer> Examples of the material of the reflective layer include metals and semi-metals which are hardly corroded and can provide a high reflectivity by themselves, and specific examples thereof include Au, Ag, Cr, Ni, and A.
Examples thereof include l, Fe, and Sn, but Au, Ag, and Al are most preferable in terms of reflectivity and productivity. Further, these metals and metalloids may be used alone or as two kinds of alloys. Examples of the method for forming the reflective layer include vapor deposition, sputtering, and the like.
0 to 3000 °.

<Protective Layer, Hard Coat Layer on Substrate Surface> The protective layer or hard coat layer on the substrate surface is composed of (a) protection of the recording layer (reflection / absorption layer) from scratches, dust, dirt, etc .; It is used for the purpose of improving the storage stability of the reflection / absorption layer), (c) improving the reflectance, and the like. As the material, those shown in the intermediate layer can be used. In addition, SiO, SiO ₂ or the like can be used as an inorganic material, and polymethyl acrylate, polycarbonate, epoxy resin, polystyrene, polyester, vinyl resin, cellulose, aliphatic hydrocarbon resin, aromatic hydrocarbon resin, natural material can be used as organic material. Thermosoftening and heat melting resins such as rubber, styrene butadiene resin, chloroprene rubber, wax, alkyd resin, drying oil and rosin can also be used.
Among the above materials, the most preferable for the protective layer or the hard coat layer on the substrate surface is an ultraviolet curable resin having excellent productivity.
The thickness of the protective layer or the substrate surface hard coat layer is 0.01 to
It is 30 μm, preferably 0.05 to 10 μm. In the present invention, the intermediate layer, the protective layer and the substrate-side hard coat layer contain a stabilizer, a dispersant, a flame retardant, a lubricant, an antistatic agent, a surfactant, a plasticizer, and the like, as in the case of the recording layer. It can be contained.

<Adhesive Layer> A transparent polymer compound can be used. Particularly preferred in the present invention, an ultraviolet-curable adhesive,
It is a hot melt type (hot melt type) adhesive or an adhesive. An ultraviolet-curable adhesive is an adhesive that starts radical polymerization by ultraviolet irradiation and cures. Its composition is
Generally, it comprises (1) an acrylic oligomer, (2) an acrylic monomer, (3) a photopolymerization initiator, and (4) a polymerization inhibitor, and the oligomer is a polyester-based, polyurethane-based, epoxy-based acrylate, or the like. The photopolymerization initiator may be benzophenone, benzoin ether, or the like. Hot-melt adhesives are liquid adhesives that are cured by solvent volatilization or reaction to develop adhesive strength, whereas adhesive strength is developed by physical changes in the heat-melting and cooling-solidification of a normal-temperature solid thermoplastic resin. is there. EVA, polyester, polyamide, polyurethane and the like can be used as the hot melt adhesive. The pressure-sensitive adhesive has viscoelasticity at room temperature, strongly adheres to both the adherend and the substrate, and has cohesive strength for a long time after adhesion. As an adhesive,
Polyvinyl ether, polyisobutylene, SBR, butyl rubber, chloroprene rubber, vinyl chloride-vinyl acetate copolymer, chlorinated rubber, polyvinyl butyral, and the like can be used.

[0036]

EXAMPLES Reference examples, examples and comparative examples of the present invention are shown below. However, the present invention is not limited by these examples.

Reference Example [Method of synthesizing nickel coordination compound of compound (1)] 15.4 g of 4-nitro-2-aminophenol was charged into 150 ml of water, and 23.6 g of 35% hydrochloric acid was added with stirring.
Was added. While cooling to 10 ° C or less, 20 ml of water,
An aqueous solution of 7.2 g of sodium nitrite was added, and the mixture was further stirred at the same temperature for 2 hours. Then, excess nitrous acid was decomposed with sulfamic acid to prepare a diazonium liquid. Next, 17.1 g of 3-hydroxy-N, N'-diethylaniline was charged into 150 ml of water, and while stirring, 20 g of 24% sodium hydroxide and 13.6 g of sodium acetate were added and dissolved. Crushed ice was added thereto, and the diazonium solution was poured while keeping the temperature at 10 ° C. or lower to carry out a coupling reaction. After completion of the reaction, the reaction mixture was filtered to obtain a wet monoazo dye. Subsequently, this wooly monoazo dye was mixed with 150 ml of ethylene glycol.
And a solution prepared by dissolving 7 g of nickel chloride in 50 ml of water was added thereto. The pH was adjusted to 8 to 10 with caustic soda and reacted at 90 to 100 ° C for about 10 hours to obtain a chromium complex dye. Since the obtained nickel coordination compound contains an excess of impurities such as inorganic salts and amines, it is preferable to use it after washing with various solvents, recrystallization, or purification by column chromatography or the like.

Example 1 Compound No. 1 was placed on a 0.6 mm thick injection molded polycarbonate substrate having a guide groove with a depth of 1400 °, a half width of 0.38 μm and a track pitch of 1.0 μm. Then, a recording layer having a thickness of 530 ° was formed by spin-coating the methyl cellosolve solution of No. 2 to obtain an optical recording medium.

Examples 2 to 5 Compound No. 1 used in Example 1 Compound N instead of 2
o. Example 1 except that 26, 43, 51 and 59 were used
An optical recording medium was obtained in exactly the same manner as described above.

Comparative Example 1 Compound No. 1 used in Example 1 An optical recording medium was obtained in exactly the same manner as in Example 1 except that the following compound (T) was used instead of Compound 2. Compound (T) is a dye used for CD-R.

Embedded image

The optical recording media of Examples 1 to 5 and Comparative Example 1 were evaluated under the following conditions. Table 15 shows the results. <Recording conditions> ・ Laser oscillation wavelength: 635 nm ・ Recording frequency: 3.75 MHz ・ Recording linear velocity: 3.0 m / sec <Reproduction conditions> ・ Laser oscillation wavelength: 635 nm ・ Repower: 0.5 to 0.7 mW continuous Light-Scanning band width: 30 KHz <Light resistance test conditions>-Light resistance test: 40,000 Lux, Xe light, continuous irradiation for 20 hours-Storage test: 85 ° C 85% 85% leaving for 720 hours

[0042]

[Table 15]

Example 6 Compound Example No. 1 was placed on an injection-molded polycarbonate substrate having a depth of 1600 °, a half-width of 0.38 μm and a guide groove having a track pitch of 0.8 μm and a thickness of 0.6 mm. 1 was dissolved in a mixed solvent of methylcyclohexane, 2-methoxyethanol, methyl ethyl ketone, and tetrahydrofuran, and a solution was applied by spinner to form an organic dye layer having a thickness of 680Å, and then a silver reflective layer having a thickness of 2000Å was formed by sputtering. And a protective layer made of an acrylic photopolymer having a thickness of 5 μm was further provided thereon to obtain an optical recording medium.

Examples 7 to 11 Compound Nos. Used in Example 6 In place of 1, compound N
o. An optical recording medium was obtained in exactly the same manner as in Example 6, except that 18, 21, 32, 58 and 62 were used.

Comparative Example 2 Compound No. 1 used in Example 6 An optical recording medium was obtained in exactly the same manner as in Example 6, except that the compound (T) of Comparative Example 1 was used instead of 1.

Comparative Example 3 Compound No. 1 used in Example 6 In place of 1, the following formula (U)
An optical recording medium was obtained in exactly the same manner as in Example 6, except that the compound was used. The compound of the following formula (U) is a dye used for CD-R.

Embedded image 中 In the formula, R represents a group of OCH [CH (CH ₂ ) ₂ ] ₂ . ｝

Evaluation tests were performed on the optical recording media of Examples 6 to 11 and Comparative Examples 2 to 3 under the following conditions. Table 16 shows the results. <Recording conditions> -Laser oscillation wavelength: 635 nm -Recording frequency: 3.75 MHz -Recording linear velocity: 3.0 m / sec <Reproduction conditions> -Laser oscillation wavelength: 635 nm -Reproduction power: 0.5 to 0.7 mW continuous Light ・ Scanning bandwidth: 30KHz

[0048]

[Table 16]

Example 12 Compound No. 1 was placed on a 1.2 mm-thick injection-molded polycarbonate substrate having a guide groove with a depth of 1000 mm, a half width of 0.40 μm and a track pitch of 0.1 μm. 1 and Comparative Example 1
Of a mixture having a weight ratio of 1: 0.7 with the compound (T) was dissolved in a mixed solvent of methylcyclohexane, 2-methoxyethanol, methylethylketone and tetrahydrofuran, followed by spinner coating to form an organic dye layer having a thickness of 1600 °. Then, a gold reflective layer having a thickness of 2000 ° was provided by a sputtering method, and a protective layer made of an acrylic photopolymer having a thickness of 5 μm was further provided thereon to obtain an optical recording medium.

Examples 13 and 14 Compound No. 1 used in Example 12 In place of 1, compound N
o. An optical recording medium was obtained in exactly the same manner as in Example 12 except for using 18, 59.

Examples 15 and 16 Compound No. 1 used in Example 12 In place of 1, compound N
o. An optical recording medium was obtained in exactly the same manner as in Example 12, except that a mixture of Compounds (2) and (62) and the compound (U) of Comparative Example 3 were used.

Comparative Examples 4 and 5 Compound No. 1 used in Example 12 An optical recording medium was obtained in the same manner as in Example 12, except that only the compound (T) of Comparative Example 1 and the compound (U) of Comparative Example 3 were used instead of 1.

Examples 12 to 16 and Comparative Examples 4 to 5
Recording at a laser oscillation wavelength of 780 nm, a recording frequency of 3.75 MHz, and a recording linear velocity of 1.4 m / sec.
The reproduction was performed with continuous light of 0.5 nm to 0.7 mW and continuous light of a semiconductor laser having a scanning bandwidth of 30 KHz. Table 17 shows the results.

[0054]

[Table 17]

[0055]

The coordination compound (dye) used in the present invention can be coated by coating, has excellent light resistance and storage stability, and can be produced industrially by using this compound. A high density optical disk can be provided. According to the first aspect of the present invention, it is possible to provide an optical recording medium which is recordable and reproducible with a laser beam having a wavelength range of 700 nm or less and has excellent light resistance and storage stability. According to the invention of claim 2, it is possible to provide an optical recording medium that can be used as a CD-R in a current system and that can reproduce recorded information even in a next-generation high-density optical disk system. According to the third and fourth aspects of the present invention, the optical recording medium according to the second aspect of the present invention has an optimum configuration, and enables recording with high quality signal characteristics. According to the fifth aspect of the present invention, it is possible to provide an optical recording medium with high productivity, high reflectivity, and high-density recording. According to the invention of claim 6, high-density recording and reproduction can be performed. According to the seventh aspect of the present invention, it is possible to provide a recording / reproducing method which can be used as a CD-R in a current system and can reproduce recorded information even in a next-generation high-density optical disk system.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of a configuration of a normal write-once optical recording medium. FIG. 2A is a view showing a type having a recording layer 2 on a substrate 1. FIG. 3B is a view showing a type having the undercoat layer 3 on the substrate 1 of FIG. (C) is a diagram showing a type having a protective layer 4 on the recording layer 2 of (b). (D) is a view showing a type having a hard coat layer 5 on the back surface of the substrate 1 of (c).

FIG. 2 is a schematic cross-sectional view of a medium configuration of a high reflectance optical recording medium (CD-R). FIG. 2A is a view showing a type having a recording layer 2, a metal reflective layer 6, and a protective layer 4 on a substrate 1. FIG. 3B is a view showing a type having the undercoat layer 3 on the substrate 1 of FIG. (C) is a view showing a type having a hard coat layer 5 on the back surface of the substrate 1 of (b).

FIG. 3 is a schematic cross-sectional view of a medium configuration for a large-capacity, high-reflectance optical recording medium (DVD-R). (A) Recording layer 2, metal reflection layer 6, adhesive layer 9 on substrate 1
FIG. 2 is a view showing a mold having a substrate and a substrate 8. FIG. 3B is a view showing a type having the undercoat layer 3 on the substrate 1 of FIG. (C) is a view showing a type having the hard coat layer 5 on the back surface of the substrate 1 of (b) and having the hard coat layer 5 on the upper surface of the substrate 8. (D) is a diagram showing a type having a semitransparent reflective layer 7, an adhesive layer 9, a recording layer 2, a metal reflective layer 6, and a substrate 8 on a substrate 1.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Substrate (lower substrate) 2 Recording layer 3 Undercoat layer 4 Protective layer 5 Hard coat layer 6 Metal reflective layer 7 Translucent reflective layer 8 Substrate (upper substrate) 9 Adhesive layer

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C09B 45/22 G11B 7/004 Z G11B 7/004 7/24 516 7/24 516 538E 538 B41M 5/26 Y (72) Inventor Yasunobu Ueno 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Co., Ltd. (72) Isao Shinmura 66-2 Horikawa-cho, Saiwai-ku, Kawasaki-shi, Kanagawa Prefecture 11F, Kowagawa Saki Nishiguchi Building Tsuchiya Chemical Industry Co., Ltd. (72) Inventor Mitsutoshi Anzai 66-2 Horikawa-cho, Saiwai-ku, Kawasaki City, Kanagawa Prefecture 11th floor of Kowagawa Saki Nishiguchi Building Hodogaya Chemical Industry Co., Ltd. F-term (reference) 2H111 EA03 EA12 EA32 EA40 EA48 FA01 FA12 FA14 FA23 FA37 FB42 FB43 GA07 5D029 JA04 JB47 JC03 JC17 5D090 AA01 BB03 CC12 DD02 FF08 FF11

Claims (7)

[Claims] 1. An optical recording medium comprising a substrate and at least a recording layer provided directly or via an undercoat layer, wherein the recording layer comprises a compound represented by the following structural formula (I) and / or (II) and a metal compound An optical recording medium comprising a layer containing at least one kind of a coordination compound (dye). Embedded image (Wherein X ₁ , X ₂ , X ₃ , and X ₄ represent a hydrogen atom, a halogen atom, a nitro group, a sulfonamide group, an alkyl group or an alkoxy group having 1 to 5 carbon atoms, and X ₁ , X ₂ , X
₃ and X ₄ may be the same or different. R ₁ and R ₂ each independently represent a hydrogen atom, an alkyl group having 1 to 8 carbon atoms or an aryl group which may have a substituent. ) [In the formula, X ₁ , X ₂ , X ₃ and X ₄ represent a hydrogen atom, a halogen atom, a nitro group, a sulfonamide group, an alkyl group or an alkoxy group having 1 to 5 carbon atoms, and X ₁ , X ₂ , X
₃ and X ₄ may be the same or different. Y ₁ , Y ₂ , Y ₃ , Y ₄ , Y ₅ and Y _{6 each} represent a hydrogen atom,
An alkyl group having 1 to 8 carbon atoms which may have a substituent,
An aryl group which may have a substituent, an amino group, an alkylamino group which may have a substituent, an acetyl group,
Represents an acetylamino group, a hydroxy group or a carboxyl group, which may be the same or different; A, B are each independently, -OH, -OCH _3,
—NH ₂ , —SH, —NHR ₃ (R ₃ has 1 to 3 carbon atoms.
A lower alkyl group) or -COOH. ] 2. The optical recording medium according to claim 1, wherein the recording layer comprises a mixed layer of at least one of the coordination compounds and a dye having a maximum absorption wavelength at 680 to 750 nm. 3. The optical recording medium according to claim 1, wherein said metal compound is a compound of at least one metal selected from the group consisting of Cr, Fe, Ni and Zn. 4. The dye having a maximum absorption wavelength at 680 to 750 nm is at least one dye selected from the group consisting of a trimethine cyanine dye, a porphyrazine dye and an azo metal chelate compound.
The optical recording medium according to the above. 5. The optical recording medium according to claim 1, further comprising a reflection layer made of Al, Ag, or Au. 6. A recording / reproducing method for reproducing from the optical recording medium according to claim 1 at a reproducing wavelength of 630 to 690 nm. 7. Recording on the optical recording medium according to any one of claims 1 to 5 at a recording wavelength of 770 to 810 nm,
A recording / reproducing method for reproducing at a reproducing wavelength of 770 to 810 nm and 630 to 685 nm.