Optical recording media

In an optical recording medium to record information by using an optical recording medium comprising a substrate and a recording layer, said recording layer consisting essentially of a light-resistant improver and an organic dye compound, as a light absorbent and being provided on said substrate, and irradiating said recording layer with a writing light to act on said organic dye compound to form a pit on said substrate, the improvement comprising

• irradiating a recording layer on a substrate with a laser beam with a wavelength of 405 nm, as the writing light, to form a pit on said substrate, wherein said recording layer exhibits an absorption maximum at a wavelength longer than the oscillation wavelength of said laser beam but absorbs said laser beam in a level sufficient to record information in said recording layer,
• whereby said optical recording medium having a recording capacity of over 15 GB per one side when formed into a disk 12 cm in diameter, by forming minute pits with a pit/groove width of below 1 μm/pit at a track pitch of below 1 μm, said organic dye compound having an absorption maximum at a wavelength of longer than 500 nm when both in a methanol solution and in a thin-layer form, absorbing a light with a wavelength of 390-450 nm, and being represented by any one of Formulae 1 to 3;
• wherein in Formula 1, Z1 and Z2 denote the same or different optionally substituted aromatic rings;
• Y1 and Y2 independently denote carbon atoms or hetero atoms;
• R1 and R2 denote optionally substituted aliphatic hydrocarbon groups;
• R3 to R6 independently denote hydrogen atoms or compatible substituents, and when Y1 and Y2 are hetero atoms, the whole or a part of R3 to R6 does not exist;
• L1 denotes a methine chain which may have a substituent and/or a cyclic group;
• and X1 denotes a compatible counter-ion;
• wherein in Formula 2, Z3 denotes an optionally substituted aromatic ring;
• Y3 denotes a carbon atom or a hetero atom;
• R7 to R9 denote the same or different optionally substituted aliphatic hydrocarbon groups;
• R10 and R11 independently denote hydrogen atoms or compatible substituents, and when Y3 is a hetero atom, R10 and/or R11 do not exist;
• L2 denotes a methine chain which may have a substituent and/or a cyclic group;
• and X2 denotes a compatible counter-ion;
• and
• wherein in Formula 3, Z4 and Z5 denote the same or different optionally substituted aromatic hydrocarbon groups or heterocycles;
• and R12 denotes an acid base.