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:
May. 07, 2002
Filed:
Oct. 09, 1998
Naoyuki Takagi, Gifu, JP;
Satoshi Sumi, Gifu, JP;
Sanyo Electric Co., Ltd., Osaka, JP;
Abstract
An optical pickup device for an AS-MO disk, a DVD and a CD includes a dual wavelength semiconductor laser with first and second oscillation devices, a polarization plane rotary unit selectively rotating a plane of polarization of a laser beam 90°, and a polarization selective diffraction grating passing a laser beam straight forward or dividing a laser beam into three beams depending upon the direction of polarization. The optical pickup device operates by the DPP tracking system where three laser beams are directed for an AS-MO disk, and by the DPD tracking system where a single laser beam is directed for a DVD or a CD. As a result, a signal can be reproduced from an AS-MO disk, a DVD, or a CD having different tracking systems.