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:
Aug. 04, 2009
Filed:
Dec. 17, 2004
Teiichiro Oka, Tokyo, JP;
Teiichiro Oka, Tokyo, JP;
TDK Corporation, Tokyo, JP;
Abstract
An optical head, capable of performing output control for a light source without weakening an intensity of a light beam for recording and reproduction even if an optical element is not added anew, and an optical recording and reproducing apparatus including the optical head. Light fluxes near the center of an optical beam emitted from a light source are made incident on a diffractive element and transmitted through a beam splitter or the like to be irradiated on an optical recording medium. On the other hand, a part of peripheral light fluxes of the light beam are reflected in a direction substantially perpendicular to an optical axis by a reflection surface of a holder provided at an end of the diffractive element. Light beams reflected on the reflection surface are made incident on a photo-detector, and the photo-detector converts the light beams into an electric signal for output monitor of the light source according to an amount of received light. This electric signal for output monitor is fed back to a drive circuit of the light source to thereby perform control for an output of the light source.