| 摘要 |
[Problems] Multilayered optical information recording media involve a problem that a BCA is erroneously formed in a different information recording layer even if the BCA is intended to be formed in a specific information recording layer. [Means for Solving the Problems] An optical information medium (1) for recording/reproducing information by applying a laser beam includes two or more recording layers (11, 12) for recording/reproducing information by receiving a laser beam at the same laser beam incident surface (1a). A geometrical irregularity (K) is formed in an area (inner peripheral side) (21) for a BCA on one recording layer (12), and a mirror surface is formed in the area of the other information recording layer (11) corresponding to the BCA area (21). The geometrical irregularity (K) is detected when focus servo is actuated so as to detect the desired information recording layer. Thus, a BCA is prevented from being erroneously formed in another information recording layer.
|
