| 摘要 |
PURPOSE:To execute sufficient compensation for a large surface deflection and to execute correct focusing by storing a surface deflection quantity detected with a detecting means and controlling a moving means in accordance with the surface deflection quantity and a timing signal due to an output means. CONSTITUTION:A storing means (memory) 24, which stores the surface deflection quantity detected by the detecting means in accordance with the timing signal due to the output means, and a control means, etc., which control moving means 4 and 5 in accordance with the surface deflection quantity stored in the memory 24 and the timing signal due to the output means, are provided. Before the recording and reproducing, surface deflection compensation data according to the surface deflection quantity of the optical disk 1 are detected, and the surface deflection compensation data are stored into the memory 24. The voltage of reversed polarity is applied to a focus control circuit 15 as a bias by the surface deflection compensation data stored at the time of the storing and reproducing, and the leftover focus is made as little as possible. Thus, a large surface deflection can be sufficiently compensated, and correct focusing can be executed. |
