| 摘要 |
PROBLEM TO BE SOLVED: To make it possible to stably maintain an adhesive state without allowing the peeling of a protective layer for a long time by forming a protective layer to the outer peripheral edge of a substrate, which protective layer completely covers a recording layer and a reflection layer. SOLUTION: Pregrooves 12 are formed to the outer peripheral edge of the substrate of the region exclusive of an inner peripheral side substrate region 14. The recording layer 13 is also disposed up to the outer peripheral edge of the substrate. The reflection layer 16 is formed to the outer peripheral edge on the recording layer, i.e., the substrate. Since the reflection layer is formed to the outer peripheral edge of the substrate, there is no need for using a mask and the problems, such as pickup of dust and generation of flaws, do not arise. The protective layer 17 to be formed on the surface of the reflection layer 16 is formed not only the reflection layer 16 but on the end face on the outer peripheral side of the substrate as well. The respective outer peripheral edges of the recording layer and the recording layer are thereby completely covered by the protective layer and, therefore, the peeling from the outer peripheral edge end (more specifically the boundary between the reflection layer and the recording layer or between the substrate and the recording layer) of the reflection layer when the medium is preserved for a long time or used for a long time is prevented. |
