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:
Jul. 20, 1976
Filed:
Jun. 26, 1974
Applicant:
Inventors:
Claude Bricot, Paris, FR;
Jean Claude Lehureau, Paris, FR;
Assignee:
Thomson-Brandt, Paris, FR;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
G11C / ; G11C / ; G11B / ;
U.S. Cl.
CPC ...
3401 / ; 1791 / ; 1791 / ; 3401 / ;
Abstract
The present invention relates to the optical read-out of a diffractive track carried by a data carrier. The object of the invention is an optical read-out device in which concentrated illumination of the track is effected by at least two collateral read-out spots straddling same, in order to produce a track eccentricity signal by subtraction of the voltages furnished by two groups of photo-electric transducers sensitive to the spread in the beams which form said spots.