Optical tracking apparatus
US4408311A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 7, 1981 |
| Grant date | Oct 4, 1983 |
| Priority date | — |
| Expiry date | May 7, 2001 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B7/12
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An optical tracking apparatus for tracing a spiral track on a recording disk includes an optical pickup device having a semiconductor laser and a photoelectric conversion element; an arm device pivotally mounted to an arm shaft with the pickup device being mounted to the free end thereof to thereby move substantially along the radial direction of the recording disk; sectorial arm drive coil attached to a rear end portion of the arm device and having a current path loop in parallel with the rotational plane of the arm device; and a pair of stationary magnetic field forming devices, each formed of a respective yoke and permanent magnet assembly, the yokes having respective air gaps in which magnetic fields in opposite directions to each other are formed, the arm drive coil being arranged to move in the air gaps and being supplied with an arm drive signal and a tracking error correction signal for causing the pickup device to trace the track.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.