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:
Sep. 19, 1995
Filed:
Nov. 14, 1994
Applicant:
Inventor:
Dieter Baas, Kehl-Auenheim, DE;
Assignee:
Deutsche Thomson-Brandt/GmbH, Villingen-Schwenningen, DE;
Attorneys:
Primary Examiner:
Int. Cl.
CPC ...
G11B / ;
U.S. Cl.
CPC ...
369 4429 ; 369 4432 ;
Abstract
An optical disc record playback apparatus includes tracking circuitry for radially translating the scanning pickup device during normal playback of the disc. Coarse and fine drive circuits are responsive to tracking error signals to provide coarse and more precise radial translations respectively. The tracking error signals are monitored for the occurrence for abnormalities such as may be produced by dust on the disc surface, and responsive to the detection of such abnormalities the coarse drive system is disabled to preclude the pickup from leaving the track.