Video disc read back scanner
US4282598A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jul 14, 1978 |
| Grant date | Aug 4, 1981 |
| Priority date | — |
| Expiry date | Jul 14, 1998 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B7/0953
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A video signal play back device derives video signals from successive tracks formed as a continuous spiral on a video disc using a light source and a lens system, which is carried by a rotatable element at a predetermined spacing from the surface of the disc and which defines a folded optical path. The rotatable element translates the lens system in the radial direction relative to the disc for "coarse" steering of the light beam along the information tracks as the disc is rotated by a turntable. The optical path includes a mirror which is articulated for rotational motion about an axis which shifts the point of impingement of the transmitted light beam upon the disc in the radial direction. The returned beam is directed to a photosensitive pick-up which provides input signals to a circuit which generates a "fine" servo control signal to drive the articulated mirror. In an alternative embodiment, a second articulated mirror is included for shifting the point of impingement of the light beam in the tangential direction, along the information tracks, for purposes of time base error correction. The radial position of the first articulatd mirror is monitored to control, with a phase sh…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.