Optical recording medium and recording method using the same

• US 6,225,022 B1
• Filed: 07/22/1998
• Issued: 05/01/2001
• Est. Priority Date: 07/22/1997
• Status: Expired due to Fees

• Current Assignee: Ricoh Company Limited
• Original Assignee: Ricoh Company Limited
• Inventors: Sato, Tsutomu, Sasa, Noboru, Higashi, Yasuhiro, Ueno, Yasunobu, Tomura, Tatsuya
• Primary Examiner(s): ANGEBRANNDT, MARTIN J
• Application Number:
  US09/120,325
• Time in Patent Office: 1,014 Days
• Field of Search: 430/270.16, 430/945, 430/270.15, 430/273.1, 369/288
• US Class Current: 430/270.16
• CPC Class Codes: G11B 2007/2571 containing group 14 elements except carbon (Si, Ge, Sn, Pb)
• CPC Class Codes: G11B 2007/25715 containing oxygen
• CPC Class Codes: G11B 7/2467 azo-dyes
• CPC Class Codes: G11B 7/2472 cyanine
• CPC Class Codes: G11B 7/248 porphines; azaporphines, e.g. phthalocyanines
• CPC Class Codes: G11B 7/2492 neutral compounds
• CPC Class Codes: G11B 7/2531 comprising glass
• CPC Class Codes: G11B 7/2533 comprising resins
• CPC Class Codes: G11B 7/2534 polycarbonates [PC]
• CPC Class Codes: G11B 7/2535 polyesters, e.g. PET, PETG or PEN
• CPC Class Codes: G11B 7/2542 consisting essentially of organic resins
• CPC Class Codes: G11B 7/2548 consisting essentially of inorganic materials
• CPC Class Codes: G11B 7/256 of layers improving adhesion between layers
• CPC Class Codes: G11B 7/2575 resins
• CPC Class Codes: G11B 7/2595 based on gold
• CPC Class Codes: Y10S 430/146 Laser beam

Abstract

An optical recording medium has a substrate and a recording layer formed thereon, the recording layer containing at least one compound represented by formula (I):

wherein M, R¹ to R⁴ and X¹ to X⁴ are as specified in the specification; and in addition, information can be recorded in the above-mentioned optical recording medium by applying a laser beam in a wavelength range of 630 to 720 nm thereto.

Claims

1. Ann optical recording medium comprising a substrate, a recording layer formed thereon and a reflection layer which is overlaid on said recording layer, wherein said recording layer comprising at least one compound represented by formula (I),

wherein M represents two independent hydrogen atoms, a bivalent, trivalent and tetravalent metal to which there may be bonded at least one oxygen atom or at least one halogen atom, or a bivalent, trivalent or tetravalent metal to which there may be bonded an unsubstituted or substituted alkyl group, an aryl group, an alkoxyl group, an aryloxy group —

(OPR¹¹R¹²)_t group, —

(OPOR¹³R¹⁴)_t group, —

(OSiR¹⁵R¹⁶R¹⁷)_t group, —

(OCOR¹⁸)_t group, —

(OR¹⁹)_t group, —

(OCOCOOR²⁰)_t group, —

(OCOCOR²¹)_t group, or —

(OCONR²²R²³)_t group;

in which R¹¹ to R²³ are each independently a hydrogen atom, a monovalent aliphatic hydrocarbon group which may have a substituent, or a monovalent aromatic hydrocarbon group which may have a substituent, and t is an integer of 0 to 2;

R¹ to R⁴ are each independently a hydrogen atom or an alkyl group which may have a substituent; and

X¹ to X⁴ are each independently a phenyl group substituted by alkyl, alkoxy, fluorine or a fluorine-atom containing group.

2. The optical recording medium as claimed in claim 1, wherein X¹ to X⁴ in formula (I) are each independently a substituted phenyl group, with all the substituents thereof being fluorine.

3. The optical recording medium as claimed in claim 1, wherein X¹ to X⁴ in formula (I) are each independently a substituted phenyl group, with all substituents thereof being fluorine-atom containing groups.

4. The optical recording medium as claimed in claim 1, wherein X¹ to X⁴ in formula (I) are each independently a substituted phenyl group, with at least one of the substituents thereof being selected from the group consisting of an alkyl group and an alkoxyl group.

5. The optical recording medium as claimed in claim 1, wherein R¹ to R⁴ in formula (I) are each independently a branched alkyl group.

6. The optical recording medium as claimed in claim 1, wherein R¹ to R⁴ in formula (I) are each independently a substituted alkyl group, with at least one of the substituents thereof being a halogen atom.

7. The optical recording medium as claimed in claim 6, wherein said halogen atom is a fluorine atom.

8. The optical recording medium as claimed in claim 1, wherein M in formula (I) is one selected from the group consisting of Cu, Co, Zn, Ni, Pd, Pt, VO, and Mg.

9. The optical recording medium as claimed in claim 1, wherein said recording layer further comprises at least one organic dye having a maximum absorption wavelength in a range of 680 nm to 750 nm.

10. The optical recording medium as claimed in claim 9, wherein said organic dye is selected from the group consisting of a pentamethine cyanine dye, a phthalocyanine dye and an azo metal chelate dye.

11. The optical recording medium as claimed in claim 1, further comprising an undercoat layer which is provided between said substrate and said recording layer.

12. The optical recording medium as claimed in claim 1, further comprising a reflection layer which is overlaid on said recording layer.

13. The optical recording medium as claimed in claim 1, further comprising a protective layer which is overlaid on said recording layer.

14. The optical recording medium as claimed in claim 1, wherein said recording layer is formed by use of a coating liquid which is prepared by dissolving at least said one compound represented by formula (I) in at least one solvent selected from the group consisting of dichloroethane, methylcyclohexane, methoxyethanol, methyl ethyl ketone and tetrahydrofuran.

15. The optical recording medium as claimed in claim 14, wherein as said solvent used is dichloroethane.

16. The optical recording medium as claimed in claim 14, wherein as said solvents are used at least two of methylcyclohexane, methoxyethanol, methyl ethyl ketone or tetrahydrofuran in combination.

17. The optical recording medium as claimed in claim 1, wherein said recording layer further comprises at least one organic dye in combination with said compound represented by formula (I), said organic dye being selected from the group consisting of:

a pentamethine cyanine dye represented by formula (II);

wherein R³¹ and R³² are each independently an alkyl group having 1 to 3 carbon atoms;

R³³ and R³⁴ are each independently an unsubstituted or substituted alkyl group having 1 to 6 carbon atoms;

X is an acid anion; and

the aromatic ring may be condensed with other aromatic ring, and may have a substituent selected from the group consisting of an alkyl group, a halogen atom, an alkoxyl group, and an acyl group,

a phthalocyanine dye represented by formula (III);

wherein M¹ is Ni, Pd, Cu, Zn, Co, Mn, Fe, TiO or VO;

X¹¹ to X¹⁴ are each independently —

OR or —

SR, in which R is an unsubstituted or substituted, straight-chain, branched or alicyclic alkyl group having 3 to 12 carbon atoms, or an unsubstituted or substituted aryl group, with X¹¹ to X¹⁴ being substituted at α

-position of each benzene ring bonded thereto, provided that each benzene ring may have as a substituent a hydrogen atom or a halogen atom except at the α

-position for the substitution of X¹¹ to X¹⁴,

a phthalocyanine dye represented by formula (IV);

wherein M¹ is Si, Ge, In or Sn;

X¹⁵ to X¹⁸ are each independently —

OR or —

SR, in which R is an unsubstituted or substituted, straight-chain, branched or alicyclic alkyl group having 3 to 12 carbon atoms, or an unsubstituted or substituted aryl group, with X¹⁵ to X¹⁸ being substituted at α

-position of each benzene ring bonded thereto, provided that each benzene ring may have as a substituent a hydrogen atom or a halogen atom except at the α

-position for the substitution of X¹⁵ to X¹⁸; and

Y¹ and Y² are each independently OSiR²⁵R²⁶R²⁷, —

OCOR²⁵R²⁶R²⁷, in which R²⁵, R²⁶ and R²⁷ are each independently an alkyl group having 1 to 10 carbon atoms or an aryl group, and

an azo metal chelate compound prepared from an azo compound of formula (V) and a metal;

wherein A is a residue which is capable of forming a heterocyclic ring in combination with the carbon atom and the nitrogen atom to which A is bonded;

B is a residue which is capable of forming an aromatic ring or a heterocyclic ring in combination with the two carbon atoms to which B is bonded; and

X is a group having an active hydrogen atom.

18. The optical recording medium as claimed in claim 17, wherein said metal for the preparation of said azo metal chelate compound is selected from the group consisting of Ni, Pt, Pd, Co, Cu and Zn.

19. The optical recording medium as claimed in claim 17, wherein the mixing ratio by weight of said compound of formula (I) to one of said organic dyes of formulas (II) to (V) is in a range of 40:

100 to 20;

100.

20. The optical recording medium as claimed in claim 1, wherein said compound of formula (I) is a mixture of four isomers thereof of formulas (A), (B), (C) and (D):

21. A method of recording information, which comprises the step of applying a laser beam in a wavelength range of 630 to 720 nm to an optical recording medium which comprises a substrate, a recording layer formed thereon and a reflection layer which is overlaid on said recording layer, wherein said recording layer comprising at least one compound represented by formula (I),

wherein M represents two independent hydrogen atoms, a bivalent, trivalent and tetravalent metal to which there may be bonded at least one oxygen atom or at least one halogen atom, or a bivalent, trivalent or tetravalent metal to which there may be bonded an unsubstituted or substituted alkyl group, an aryl group, an alkoxyl group, an aryloxy group —

(OPR¹¹R¹²)_t group, —

(OPOR¹³R¹⁴)_t group, —

(OSiR¹⁵R¹⁶R¹⁷)_t group, —

(OCOR¹⁸)_t group, —

(OR¹⁹)_t group, —

(OCOCOOR²⁰)_t group, —

(OCOCOR²¹)_t group, or —

(OCONR²²R²³)_t group,

in which R¹¹ to R²³ are each independently a hydrogen atom, a monovalent aliphatic hydrocarbon group which may have a substituent, or a monovalent aromatic hydrocarbon group which may have a substituent, and t is an integer of 0 to 2;

R¹ to R⁴ are each independently a hydrogen atom or an allyl group which may have a substituent; and

X¹ to X⁴ are each independently a phenyl group substituted by alkyl, alkoxy, fluorine or a fluorine-atom containing group.