| 摘要 |
PROBLEM TO BE SOLVED: To provide a high-density optical disk with a decreased eccentricity which is recorded and reproduced with a laser beam of wavelength of nearly 400 nm. SOLUTION: A substrate 2 comprising the first circular area part 9 with a first depth d1 in whose center a center hole 8 is formed and the second circular area part 10 with a second depth d2 which is formed adjacent to the outside of the first circular area part 9; the first protective layer 3, a recording layer 4, the second protective layer 5 and a reflecting layer 6, which are each laminated in order on the second circular area part 10; and a rigid substrate 7 bonded together on the reflecting layer 6 having an aperture part 7A, which is the same in diameter as the first circular area part 9, are provided. Then, the first depth d1 is larger than the second depth d2. |
