Optical recording medium

Abstract

An optical recording medium is provided in which a recording layer contains a salt-forming dye between an ion of an azo metal complex of the following formula (I) and an ion of a cyanine dye of the following formula (II), having a complex index of refraction in the wavelength region of recording light and/or reading light whose imaginary part k is up to 0.20, or at least one of azo oxovanadium metal complexes having an azo compound of the following formula (III) as a ligand and metal complexes having azo compounds of the following formulae (IV) and (V) as a ligand. Recording and reading can be carried out at a conventional wavelength or a short wavelength of about 630-690 nm or both. In formulae (I) and (III), A is an aromatic ring group having an active hydrogen-bearing group at a position adjacent to the diazo group or a nitrogenous heteroaromatic ring group having an oxovanadium-coordinatable nitrogen atom at a position adjacent to the carbon atom in the ring attached to the diazo group, and B is an aromatic ring group having an active hydrogen-bearing group at a position adjacent to the diazo group. In formula (I), m is equal to 1 or 2, and M1 is a center metal. In formula (II), Q1 and Q2 each are a group of atoms forming a 5-membered nitrogenous heterocyclic ring which may have a fused ring, L is a methine chain, R1 and R2 each are an alkyl group. In formulae (IV) and (V), X is an active hydrogen-bearing group, R1 and R2 each are an alkyl group, the total number of carbon atoms in R1 and R2 is from 2 to 8, R is a nitro group, and n is equal to 0 or 1.

Dependencies are inferred from the claim text.