Patent ID: 6288997
Filing Date: 2001-09-11
Classification: G11B

Abstract:
A phase change optical disk medium including a disk-like substrate and a recording layer constituted of a plurality of lamination-thin films having a phase change film to record information marks with an amorphous phase and crystal phase changed, and having tracks formed concave-convex like grooves on said recording layer with lands and grooves arranged to record said information marks wherein,a track interval has a range from equal to or greater than 0.54 .mu.m to equal to or less than 0.64 .mu.m, whereina reproduced signal amplitude of a shortest information mark recorded on said recording layer has a ratio equal to or greater than 17% of a reproduced signal amount by an optical reflectance of said recording layer when said phase change film is changed to the crystal phase state, and whereina length of said shortest information mark is in a range of 0.39 .mu.m to 0.46 .mu.m.