| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical disk which maintains the state of a recording and reproducing beam constant without depending upon the change in the record ing state of a first recording film in subjecting a second recording film to record ing and reproducing of a recording and reproducing type optical disk having two layers of the recording films, a method of manufacturing optical disk, optical disk device and method of recording and reproducing optical disk. SOLUTION: The optical disk is so constituted, in subjecting the recording film 131 which is the second recording film to recording and reproducing by using a bifocal objective lens 10 for 0.6t/1.2t, that the recording and reproducing beam 150 is transmitted through a disk substrate 20, the recording film 130, adhesive layer 30, the recording film 131 and a disk substrate 21 and is reflected by an aluminum reflection layer 40 and is thereafter focused at the recording film 131. |
