| 摘要 |
PURPOSE:To prevent an access speed from being dropped, to omit a magnetic shield and to obtain a miniaturized and simple constitution by controlling the positioning a head carrying mechanism in accordance with the photodetecting quantity of plural photodetectors linearly arrayed in the radial direction of a magnetic disk. CONSTITUTION:A projector 16 for radiating light beams to a slit 18a in a prescribed range is fixed to a member 8 for supporting a magnetic head H, a solid state image pickup element 17 having plural photodetecting elements linearly arrayed in the radial direction of magnetic disks 1, 2 at a pitch thinner than the track pitch of the disks 1, 2 is arranged oppositely to the projector 16 and a head carrying mechanism 5 is controlled by a servo control correspondingly to the photodetecting quantity of the element 17 to position the magnetic head H on a specified track. Thereby, it is unnecessary to record servo information on a magnetic disk and the absolute positions of the magnetic head H are continuously detected to control the positioning of the magnetic head H. Consequently, the access speed can be prevented from being dropped and the miniaturized and simple constitution can be obtained. |
