Patent ID: 7354694

Claim:
In an optical recording medium comprising an organic dye compound which has an absorption maximum at a wavelength of 400 nm or shorter, the improvement wherein the organic dye compound is a styryl dye represented by Formula 1 which substantially absorbs a visible light with a wavelength of around 400 nm, said optical recording medium being constructed so as to record information by using a laser beam with a wavelength of 450 nm or shorter, at a recording level of exceeding 4.7 GB (giga bytes) per one side by forming pits having a pit width of below 0.4 Î¼m/pit and a track pitch of below 0.74 Î¼m when formed into a disk, 12 cm in diameter: wherein in Formula 1, Ã¸1 represents a heterocycle represented by any one of Formulae 2 to 8; Ã¸2 represents an aromatic ring which has a substituent selected from the group consisting of halogen, cyano, nitro, and carboxy, or heterocycle having one or more nitrogen atoms; R 1 represents a hydrogen atom, an aliphatic hydrocarbon group, ether group, acyl group, halogen, or cyano group, and the aliphatic hydrocarbon group, ether group, or acyl group may have a substituent; X âˆ’ represents as a counter ion an azo organic metal complex ion; and â€œnâ€ is a number of X âˆ’ to balance the electric charge in the styryl dye: throughout Formulae 2 to 7, A represents an optionally substituted monocyclic- or polycyclic-aromatic ring or heterocycle; when A is not present in Formulae 2 to 7, one or more substituents similar to those that are bound to A may be in the position where A is located; throughout Formulae 2 to 8, R 2 represents an optionally substituted aliphatic hydrocarbon group and R 3 represents a hydrogen or an optionally substituted aliphatic hydrocarbon group which is identical to or different from R 2 .