| 摘要 |
PROBLEM TO BE SOLVED: To make an optical disk device recordable a program for a long time by effectively utilizing characteristics of an optical disk. SOLUTION: Desired video signals and audio signals are recorded on the optical disk set to 120 mm in diameter and 10-117 μm in thickness of a light transmission layer with the shortest pit length or the shortest mark length of 0.3 μm or less via an optical system, the optical disk side of which is flat of 560 μm or less in a working distance by first and second aspherical lenses and 0.78 or more in numerical aperture. |
