Optical information recording medium and information recording and reproducing method therefor

摘要

An optical information recording medium includes a thin film material formed on a substrate; the optical constant of this thin film material is changed upon application of an incident light beam, such that the optical phase of reflected or transmitted light is shifted thereby reproducing a signal by detecting the change in either the reflected or transmitted light due to this optical phase change. It is also possible perform signal reproduction equivalent to conventional concave-convex pit methodology, but without being accompanied by resulting media deformation, thereby improving the recording density. It is easy to interchange with optical recording media of the write-once and read-only types, and, furthermore, it is possible to erase and rewrite at will.