| 摘要 |
PURPOSE:To execute an exact tracking, and also to design easily a driving part by holding as one body an objective lens and a photodetecting means, and holding this holding member so as to be movable in the tracking direction and the focusing direction against a device body. CONSTITUTION:A titled device is provided with a holding member 16 for holding as one body an objective lens 5 and an optical member containing a photodetector 8 required for converting photoelectrically a reflected light which has passed through a beam splitter 3, and also an elastic means 10 for holding this holding member 16 so as to be movable in the tracking direction and the focusing direction is provided between the holding member 16 and a device body 13. The holding member 16 is brought to a tracking servo by a tracking error signal obtained by inputting a signal obtained from the photodetector to a tracking servo- device 11, and the holding member 16 is brought to a focusing servo by a focusing error signal obtained by a focusing servo-device. In this case, the photodetector 8 is displaced as one body with the objective lens 5, therefore, the optical axis of the objective lens 5 and the split line of the photodetector 8 are not shifted. |
