OPTICAL INFORMATION RECORDING MEDIUM, ITS INFORMATION RECORDING METHOD, ITS INFORMATION REPRODUCING METHOD AND ITS INFORMATION ERASING METHOD

摘要

PROBLEM TO BE SOLVED: To provide an optical information recording medium in which the transmissivity of a phase-change recording film can be made substantially uniform irrespective of the existence of a recording operation and in which information can be recorded, reproduced and erased preferably at high density and satisfactorily, and to provide its information recording method, its information reproducing method and its information erasing method. SOLUTION: A phase-change recording film 22 in which information is recorded and erased due to a phase change when a laser beam is irradiated is formed on a phase-change-type optical recording layer 2a which is situated in the uppermost layer out of a plurality of phase-change-type optical recording layers. In addition, a transparent upper-part protective film 23 which protects the phase-change recording film 22 from a thermal deformation mainly in the recording operation and the erasing operation of the information is formed in the upper part of the phase-change recording film 22. A transparent lower-part protective film 21 which protects the phase-change recording film 23 from a thermal deformation in the recording operation and the erasing operation of the information is formed in the lower part of the phase-change recording film 22. A substrate interference film 25 which adjusts the transmissivity of the laser beam in the phase-change recording film 22 is formed under the transparent lower-part protective film 21.