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. 11, 1999
Filed:
Aug. 29, 1997
Noriaki Nishi, Chiba, JP;
Kimihiro Saito, Saitama, JP;
Kazuyoshi Horie, Chiba, JP;
Yasuo Sasaki, Kanagawa, JP;
Kenji Araki, Chiba, JP;
Kazuhiko Okamatsu, Chiba, JP;
Sony Corporation, Tokyo, JP;
Abstract
A small size, high performance optical pickup device using a light reception/emission element (laser coupler) and more particularly, an optical pickup device which is capable of excellent recording and reproduction for a magnetic optical recording medium. A prism disposed over optical detectors is made of double refractive crystal material. An optical detector for receiving extraordinary ray is formed at a position laterally deviated corresponding to so-called walk-off of the extraordinary ray. Tracking error signal is detected depending on a distribution of intensities of spots formed by reflective beams on respective optical detectors.