Patent ID: 7241555

Claim:
An optical information recording medium comprising a substrate; and a recording layer provided on the substrate, to which recording layer information can be recorded and from which the information can be replayed by laser irradiation, wherein the substrate comprises a transparent disc-shaped substrate having a pregroove with a track pitch of 0.2 to 0.5 μm formed thereon, and the recording layer is provided on a surface of a side of the substrate on which surface the pregroove is formed, and wherein the recording layer comprises a compound represented by the following formula wherein at least one of X 1 and X 2 is a hetero atom, and X 1 and X 2 form a five- or six-membered hetero ring (A) selected from the group consisting of benzothiazoline ring, a benzoxazoline ring, and a benzodithiol ring, each of which may be further fused with other aromatic rings; Y 1 and Y 2 are substituents, at least one of Y 1 and Y 2 represents —CN, —COR 1 , —COOR 2 , —CONR 3 R 4 , —SOR 5 , —SO 2 R 6 or —SO 2 NR 7 R 8 , each of R 1 to R 8 represents a hydrogen atom an alkyl group or an aryl group, and Y 1 and Y 2 may be linked together to form a ring other than a 2-thiohydantoin ring.