| 摘要 |
PROBLEM TO BE SOLVED: To control not to generate a deviation of an optical axis caused by a tracking control and a jitter error caused by rotational oscillation. SOLUTION: A movable deflection means 22 to deflect a luminous flux emitted from a fixed optical system 5 is fitted on a lens holder 26, and a fixed deflection means 4 to deflect the luminous flux and make it incident onto an objective lens 3 is fitted to a head base. Since the movable deflection means 22 moves in one body with the objective lens 3, no deviation of an optical axis is generated on the optical axis of the luminous flux made incident on the objective lens 3 from the fixed optical system 5 via each deflection means 22 and 4. Also, a distance in a focusing direction between a gravity center position of a movable part 33 and a principal point of the objective lens 3 is roughly made to coincide with the focus distance of the objective lens 3, and even if the movable part 33 is rotationally resonated in the jittering direction to change an angle of the luminous flux incident on the objective lens 3, the objective lens 3 is moved by a distance to cancel a deviation of an image- forming position caused by the inclination of the luminous flux, and thus an image-forming light spot on an optical disk 2 is controlled not to be deviated in the jittering direction. |
