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:
Feb. 01, 2005
Filed:
Dec. 19, 2001
Osamu Miyazaki, Soraku-gun, JP;
Ikuo Nakano, Yamatokoriyama, JP;
Osamu Miyazaki, Soraku-gun, JP;
Ikuo Nakano, Yamatokoriyama, JP;
Sharp Kabushiki Kaisha, Osaka, JP;
Abstract
An optical pickup device includes a detection-use condenser lens for focusing a reflected light from a disk of a light emitted from a light source; a hologram element for dividing a light passed through the detection-use condenser lens into a light passed through a high numerical aperture region and a light passed through a low numerical aperture region; and a photodetector including at least a first light receiving element for detecting the laser beam which passed through the high numerical aperture region and a second light receiving element for detecting the laser beam which passes through the low numerical aperture region. Based on output signals from the first light receiving element and the second light receiving element, a focus error signal FEand a focus error signal FEare prepared respectively. According to an output value of the photodetector, a focus control is performed based on the error signal FEor the focus error signal FE