| 摘要 |
PURPOSE:To attain power saving and the miniaturization of an optical head device by arranging a movable part required for focusing control and tracking control, etc., in the neighborhood of the center axis of the rotation of a rotary drum. CONSTITUTION:The focusing control can be attained by performing the moving control of a collimation lens L1 in a direction of (b) by a driving circuit 20 based on a signal supplied from a focusing servo circuit, and the tracking control can be attained by performing the conversion of the angle of a polarizing beam splitter BS in a direction of (c) by a driving circuit 21 based on the signal supplied from a tracking servo circuit. At this time, since the conversion of the positions or the angles of the collimation lens L1 and the polarizing beam splitter BS are performed almost in the center axis a-a' of the rotation, it is enough to prepare driving devices provided ordinary driving forces as the driving devices 20 and 21. |
