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:
Dec. 02, 2008
Filed:
Mar. 25, 2003
Joseph Colineau, Bures sur Yvette, FR;
Jean-claude Lehureau, Sainte Genevieve des Bois, FR;
Joseph Colineau, Bures sur Yvette, FR;
Jean-Claude Lehureau, Sainte Genevieve des Bois, FR;
Thales, , FR;
Abstract
The invention relates to a radial slaving method and to a reproduction device implementing it for optical discs. In an optical head of a conventional reproduction device using a four-quadrant detector with four photodiode is distributed on either side of a direction parallel to the axis of the track, the individual signals of the photodiodes (dto d) are combined in order to obtain read signals along the two diagonals (diag, diag) by subtraction (). A phase comparison signal circuit () makes it possible to construct a radial error signal (Sr) by measuring the phase shift of the diagonal read signals. The invention applies in particular to phase discs with slightly phase-shifting marks.