Phase change optical recording medium and its writing with high reliability after long period use and/or high environmental temperature storage

摘要

Prevented is the reliability loss in phase change optical recording media during high-temperature storage, and also prevented is the phenomenon of self-erase by which a part of record marks having been formed in the media are erased due to the lateral heat diffusion into the recording layer while recording laser beams are irradiated to the media. The optical recording medium disclosed has a recording layer of a phase change type and is applied to driving units for overwriting it at a linear velocity of V.sub.0. The medium is so designed as to satisfy the requirement of 1 V.sub.max /V.sub.0 1.5, where V.sub.max indicates the linear velocity at which the medium being overwritten has a highest C/N ratio.