| 摘要 |
PURPOSE:To perform high speed tracking control and focusing control with high precision by minimally suppressing a deviation amount of an optical axis of an incident beam to an objective lens and the deviation of the optical axis to a signal detecting optical system due to a lens shift. CONSTITUTION:The optical system is separated to a movable part 2 and a fixed part 3, and a floating type optical head part is provided on the movable part, and a relay lens optical system 34 performing tracking control is provided on the fixed part. A lens RL2 placed to the movable part 2 side among the relay lens optical system 34 is fixedly arranged at least in a vertical direction (y) of the optical axis lambda0. Further, the lens RL1 placed to the light source 30 side of the fixed part 3 among the optical system 34 is arranged so as to move only in the vertical direction (y) of the optical axis. The fine control in the tracking control is performed by moving the lens RL1 of the light source side based on a tracking error signal ST. |
