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:
Mar. 01, 2011
Filed:
Jan. 17, 2008
Takuya Matsumoto, Hachioji, JP;
Junichiro Shimizu, Hino, JP;
Takuya Matsumoto, Hachioji, JP;
Junichiro Shimizu, Hino, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
A second waveguide is formed near a first waveguide for guiding light to the vicinity of a main pole of a thermally assisted magnetic recording head, and a portion of light propagated through the waveguideis branched to the second waveguide. The light transmitting in the second waveguide is detected by a photodetector to detect an intensity of the light propagated through the first waveguide. In the magnetic recording apparatus, an intensity of a semiconductor laser is decreased when an amount of light incident to the photodetector is large and the intensity of the semiconductor laser is increased when the amount of light incident to the photodetector is small. By constituting a feedback loop as described above, the intensity of the light propagated through the first waveguide is kept constant.