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:
Jan. 30, 2007
Filed:
Jan. 21, 2004
Christian Büchler, Villingen-Schwenningen, DE;
Steffen Lehr, Villingen-Schwenningen, DE;
Christian Büchler, Villingen-Schwenningen, DE;
Steffen Lehr, Villingen-Schwenningen, DE;
Thomson Licensing, Boulogne-Billancourt, FR;
Abstract
The present invention relates to an apparatus for reading from and/or writing to optical recording media, which has a tracking device, a four-quadrant detector, two summation points and a phase comparator for tracking in accordance with the differential phase detection method, and also various delay elements that can be set by a control device. The object of the present invention is to propose an apparatus of this type which exhibits the best possible compensation of the error in the track error signal and thus in the tracking signal, the said error being caused on account of the lens movement. To that end, the invention provides for analogue delay elements to be arranged upstream and digital delay elements to be arranged downstream of the summation points. The present invention is suitable for apparatuses for reading from and/or writing to optical recording media, such as CD, CDI, CD-ROM, DVD, CDR and others.