The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Aug. 04, 1981
Filed:
Jul. 14, 1978
James E Elliott, San Pedro, CA (US);
Discovision Associates, Costa Mesa, CA (US);
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 shift equal to one-quarter revolution of the disc, tangential movement of the second articulated mirror.