| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical information recording medium which is converted in a unreadable state, after a reusable state for a definite time period and to provide a producing method of the optical information recording medium, a reproducing device and a reproducing method of the optical information recording medium. SOLUTION: In the optical information recording medium 1, a user data region 3, where reproducible information is recorded and a lead-in area part 2 where disk information of the user data region 3 is recorded, are formed on a substrate. The lead-in area part 2 is formed of a phase changing material which deteriorates at a deteriorating speed corresponding to prescribed regenerative light power and the disk information is recorded, by utilizing phase change of the phase changing material. Accordingly, only the lead-in area part 2 can be converted in the unreadable state, corresponding to the regenerative light power and further can be re-converted in a reproducible state by re-recording the dish information in the lead-in area part 2 which is in the unreadable state. Thus unfair utilization can be properly prevented, while solving the environmental problems. |
