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:
Nov. 02, 1993
Filed:
Apr. 28, 1992
Applicant:
Inventors:
Philippe Refregier, Palaiseau, FR;
Brigitte Loiseaux, Villebon sur Yvette, FR;
Jean-Pierre Huignard, Paris, FR;
Assignee:
Thomson-CSF, Puteaux, FR;
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G11B / ;
U.S. Cl.
CPC ...
369100 ; 369 94 ; 369107 ; 369284 ;
Abstract
The invention relates to the reading of optical disks in which the recording is performed in volume in separate layers. Reading a bit recorded within the layers gives a signal with a background noise from all the adjacent bits illuminated by the read beam. In order to eliminate this background noise, the read beam is modulated in position about the bit to be read, either horizontally or vertically with respect to a recording level. The background noise remains unchanged but the signal from the bit being read becomes a periodic signal.