Patent ID: 7223521
Filing Date: 2007-05-29
Classification: C09B,G11B,Y10S

Abstract:
1. The optical recording medium comprising: a substrate; and at least one recording layer arranged on or above the substrate, wherein the recording layer comprises two or more different squarylium-metal chelate compounds represented by following Structural Formula (1): wherein M represents a metal atom capable of coordinating; “a” “b” and “c” each represent a squarylium dye ligand represented by following Structural Formula (2), where “a” is different from “b”; and “c” may be the same as or different from “a” or “b”; and “m ” represents 0 or 1: wherein R 1 and R 2 are the same or different and each represents one of an alkyl group, an aralkyl group, an aryl group and a heterocyclic group, each of which may be substituted; and X represents one of an aryl group which may be substituted, a heterocyclic group which may be substituted and Z 3 =CH—, wherein Z 3 represents a heterocyclic group which may be substituted, wherein the recording layer further comprises at least one formazan-metal chelate compound comprising a metal and a formazan compound represented by following Structural Formula (4): wherein Ring Y represents a nitrogen-containing 5-membered or 6-membered ring which may be substituted and which may be condensed with another ring; Z represents an atomic group constituting Ring Y; and A and B each represent a substituent, and wherein the content of the formazan-metal chelate compound in the recording layer is from 20% by weight to 40% by weight and the weight ratio of the squarylium-metal chelate to the formazan-metal chelate compound is from 80:20 to 60:40.