| 摘要 |
An optical disk apparatus has a first optical system (6, 8) having an objective lens with a first NA, a second optical system (6, 8) having an objective lens with a second NA lower than the first NA, addition means (57) for adding focus error signals detected by the first and second optical systems, and alignment means (28) for aligning the objective lens in accordance with the addition result of the addition means. <IMAGE> |
