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. 16, 2007
Filed:
Oct. 04, 2002
Takahiro Miyake, Kyoto, JP;
Takahiro Miyake, Kyoto, JP;
Sharp Kabushiki Kaisha, Osaka, JP;
Abstract
Part of reflected light from an optical disc enters a diffraction element (). The ±first-order diffracted light and zero-order diffracted light from the diffraction device () travel via a cylindrical lens () and a spot lens () and enter a photodetector (). If an objective lens shifts, a beam on the diffraction element () also shifts. Therefore, the intensity distribution of a spot of the zero-order diffracted light falling on light-receiving areas (A, B, C, D) of a four-part light-receiving element () becomes bright as a whole, while the intensity distributions of spots of the ±first-order diffracted light falling on light-receiving areas (E, F) of light-receiving elements () become dark as a whole. Thus, an optical pickup tracking error detecting method and an optical pickup device enabling good tracking control are provided.