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. 12, 1991
Filed:
Oct. 20, 1989
Kenji Torazawa, Ogaki, JP;
Satoshi Sumi, Gifu, JP;
Seiji Murata, Gifu, JP;
Shigekazu Minechika, Gifu, JP;
Sanyo Electric Co., Ltd., Moriguchi, JP;
Abstract
An erasing beam B1 and a recording beam B2 emitted from a laser diode array 20 are focused on different tracks of a optical magnetic disk D, the erasing beam B1 being focused on a track located ahead of a track on which the recording beam B2 is focused. The reflected beams of the erasing beam B1 and the recording beam B2 are separated respectively into two polarized components by means of a polarized beam splitter 17 and the polarized components are received by photo sensor means 23 and 24. Based on outputs of the photo sensor means 23 and 24, an address signal, a focus error signal and a tracking error signal are obtained. At the time of reproduction, the laser diode array 20 emits a reproducing beam so that the photo sensor means provide a reproducing signal.