| 摘要 |
PROBLEM TO BE SOLVED: To enable an optical information to be reproduced even in any of CD and DVD reproducers corresponding to optical disks whose substrate thicknesses and recording formats are different by having a constitution having plural recording layers. SOLUTION: Since a second information surface 110 is covered with a third reflection film 111 reflecting the laser beam 402 having a first wavelength emitted from an optical pickup for DVD 401, the laser beam 402 having the first wavelength is modulated according to the pit string formed on the second information surface 110 to be made incident on the optical pickup for DVD 401 in a path opposite to an incident path and reproduces only information recorded on the second information surface 110. Moreover, at the time of reproducing a first information surface 105 on which information are recorded by being pursuant to a CD standard, the laser beam 404 having a second wavelength emitted from an optical pick for CD 403 is reflected on a second reflection film 108 and it passes through a transparent substrate 104 again and it reaches the first information surface 105 to be focused. Since the first information surface 105 is covered with a first reflection film 106 reflecting the laser beam 404, the laser beam 404 is modulated according to the pit string formed on the first information surface 105 to be returned to the pickup for CD 403 in a path opposite to an incident path and it reproduces only information recorded on the first information surface 105. |
