| 摘要 |
PURPOSE:To contrive higher writing sensitivity and reading S/N in the case of using long-wavelength rays such as semiconductor laser rays and contrive higher raw preservability, by providing a recording layer comprising a specified light-absorptive coloring matter, on a substrate. CONSTITUTION:A light-absorptive coloring matter of the formula phi<+>-L/phi(X<->) is incorporated in a recording layer of an optical recording medium. In the formula phi<+> is a 4,5-benzoindolenine ring residue having a plus charge on the N atom. in an indole ring, whereas phi is a 4,5-benzoindolenine ring residue having a neutral N electron, the respective 4,5-benzoindolenine rings may have various substituent groups, e.g., halogens or alkyls, connected thereto, and they may be either the same or different. The coloring matter, where it is a heptamethine coloring matter, can be easily synthesized by the so-called Zinck (Dickmann) reaction utilizing the cleavage of a pyridine derivative. The recording layer is provided by a conventional method using a ketone, ester, ether, haloalkyl or other similar solvent. In the formula, L is a linking group for forming a cyanine coloring matter. |
