Patent ID: 7449279
Filing Date: 2008-11-11
Classification: G11B,Y10S

Abstract:
1. An optical information recording medium comprising: a substrate in which at least one of a groove and a pit is formed; a recording layer located overlying the substrate and including plural dyes; and a reflection layer located overlying the recording layer, wherein the optical information recording medium has an absorbance curve with an absorbance L of from 10 to 40% against light having a wavelength λ of from 645 nm to 670 nm, a ratio (Lmax/Lmin) of a maximum absorbance Lmax of the absorbance curve to a minimum absorbance Lmin of from 1.0 to 2.0 at the wavelength range of from 645 nm to 670 nm, and a reflectance of from 45 to 85% against the light having a wavelength λ of from 645 nm to 670 nm; wherein each of the plural dyes has an absorbance curve, and wherein slopes dL/dλ of the respective absorbance curves of the plural dyes are different; wherein the plural dyes comprise a first dye compound (α) and a second dye compound (β), and wherein the absorption curve of the first dye compound (α) has a maximum absorbance at a wavelength of from 550 nm to 650 nm, and the absorbance curve of the second dye compound (β) has a maximum absorbance at a wavelength of from 650 nm to 750 nm; and wherein the first dye compound (α) is a formazan chelate compound having the following formula (I):  wherein Z represents a group which forms a polyheterocyclic ring while sharing bond with a carbon atom and a nitrogen atom, wherein the polyheterocyclic ring optionally has a substituent selected from the group consisting of alkyl groups, alkoxy groups, thioalkoxy groups, substituted amino groups, aryl groups, aryloxy groups, anilino groups and keto groups; A represents an alkyl group, an aralkyl group, an aryl group or a cyclohexyl group, which are optionally substituted with a group selected from the group consisting of alkyl groups, alkoxy groups, halogen atoms, keto groups, carboxyl groups, carboxyester groups, nitrile groups and nitro groups; B represents an aryl group, wherein the aryl group is optionally substituted with a group selected from the group consisting of alkyl groups, alkoxy groups, halogen atoms, carboxyl groups, carboxyester groups, nitrile groups and nitro groups; M represents a divalent metal atom; and n represents the number of the formazan ligand.