| 摘要 |
PROBLEM TO BE SOLVED: To provide a phase transition type information recording medium having both a rewritable area and a WORM(write-once-read-many) type area. SOLUTION: The information recording medium having a recording area consisting of a multi-layered structure including a first dielectric layer, a phase transition recording layer, a second dielectric layer and a reflective radiation layer on a substrate is disclosed. The information recording medium has the rewritable area where information is rewritable and the WORM(write-once-read- many) type area where the thickness of the second dielectric layer is designed to be thinner than that in the rewritable area and only the additional writing of information can be performed. If the thickness of the second dielectric layer is partially made thinner than the normal film thickness, the thermal condition of the recording layer is changed and the change from a crystal state to an amorphous state can not be realized by rewriting laser output in the area where the thickness is set thinner. |
