OPTICAL INFORMATION MEDIUM

摘要

PURPOSE:To improve general-purpose properties and shelf stability by using the counter ions having a specific ionic radius (nm) of cyanine dyes in an optical information medium, in which a dyestuff contained layer containing cyanine dyes is formed onto a transparent substrate. CONSTITUTION:A dyestuff contained layer 2 containing cyanine dyes is formed onto the top face of a transparent substrate 1 in an optical information medium. The counter ions having ionic radii of 0.294nm or more of cyanine days are employed at that time. Either of each ion shown in each formula mentioned separately respectively is used as the counter ions of cyanine dyes. Accordingly. the optical information medium capable of being also employed as a writing once type and a writable type besides a ROM type and having excellent shelf stability is acquired.