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. 17, 2011
Filed:
Oct. 17, 2008
Shinnosuke Torii, Kawasaki, JP;
Shinnosuke Torii, Kawasaki, JP;
Canon Kabushiki Kaisha, Tokyo, JP;
Abstract
An apparatus for effecting at least one of recording and reproducing information. A first light source has a light intensity and emits a light beam having an emission wavelength. A second light source has another light intensity and emits a light beam having an emission wavelength different from that of the first light source. An optical system guides a light beam emitted from the first light source to a recording medium and guides a light beam reflected from the recording medium to a first photodetector, which generates an output. Another optical system guides a light beam emitted from the second light source to the recording medium and guides another light beam reflected from the recording medium to the second photodetector. A separating optical element guides the light beam emitted from the first light source to the second photodetector, which generates an output. A control circuit receives the output generated by the second photodetector, and controls the light intensity of the first light source based on the output of the second photodetector.