| 摘要 |
PROBLEM TO BE SOLVED: To provide a high-density optical recording medium in which a warpage occurring on a disk or an optical strain (birefringence) is reduced, and the deterioration of signal characteristics sufficiently suppressed over the whole area of the disk in a DVD-R and a DVD-RW. SOLUTION: The thickness of the substrate for recording, through which a laser beam for recording/reproducing passes, changes uniformly and consecutively in a radial direction. |
