| 摘要 |
PURPOSE:To attain accurate follow-up to an information track as well as the stable track jump for a light spot by detecting the tracking direction of a condenser lens to the head base of an optical head and controlling the condenser lens at a fixed position. CONSTITUTION:The position of a lens mobile part 8 including a condenser lens is detected in the tracking direction to a head base 1 contained in an optical head 0 by a lens position detector 6 welded to the base 1. The head 0 is driven via a head position control circuit 16 and a head actuator 12 and then positioned with control so that a lens position signal, i.e., the output of the detector 6 is set at 0. When a track jump is carried out, a track jump instruction 11 is given from the outside to a tracking position control circuit 5. Then the part 8 is shifted by an amount equal to a track via a tracking actuator 7. A light spot 9 has a track jump and is positioned at the adjacent tracking guide groove. |
