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:
Nov. 04, 2008
Filed:
Apr. 04, 2005
Giichi Shibuya, Tokyo, JP;
Teiichiro Oka, Tokyo, JP;
Koji Mishima, Tokyo, JP;
Daisuke Yoshitoku, Tokyo, JP;
Kenji Yamaga, Tokyo, JP;
Giichi Shibuya, Tokyo, JP;
Teiichiro Oka, Tokyo, JP;
Koji Mishima, Tokyo, JP;
Daisuke Yoshitoku, Tokyo, JP;
Kenji Yamaga, Tokyo, JP;
TDK Corporation, Tokyo, JP;
Abstract
The invention relates to a light-receiving element for receiving a reflection of laser light irradiated to a rotating multi-layer recording medium having a plurality of information recording layers stacked one over another and for converting the light into an electrical signal, an optical head having the element for recording information in the multi-layer recording medium or reproducing information recorded therein, and an optical recording/reproducing apparatus and a method of optical recording and reproduction. The invention provides a light-receiving element, an optical head, an optical recording/reproducing apparatus, and a method of optical recording and reproduction which make it possible to eliminate a noise component superimposed on reflected light from a multi-layer recording medium to reproduce an RF signal of high quality. The light receiving element receives a reflection of laser light irradiated through an objective lens to a rotating multi-layer recording medium having a plurality of information recording layers stacked one over another through a return path optical system and converts the reflected light into an electrical signal. The element has a first light-receiving section having a circular light-receiving region and a second light-receiving section disposed adjacent to the outer circumference of the first light-receiving section in the form of a circle concentric therewith.