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:
Apr. 23, 2002
Filed:
Apr. 21, 1998
Abstract
A focus/tracking method and system is provided for use in an optical drive with a possibly multiple-wavelength laser source for control of the focus/tracking of the pickup head of the optical drive. The use of a multiple-wavelength laser source allows the optical drive to read data from various types of optical discs. The focus/tracking method and system combines the use of a differential, dual optical channel method for focusing control of the laser beam used to read data from the optical disc and the use of the single-beam tracking method for tracking control of the same. The focus error signal and the tracking error signal can be obtained from the same set of multi-element photodetectors. The structure of the system can therefore be simplified to include a reduced number of constituent components thus allowing a reduction in manufacturing cost.