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. 27, 2001
Filed:
Jan. 13, 2000
Tadaaki Suda, Saitama, JP;
Asahi Kogaku Kogyo Kabushiki Kaisha, Tokyo, JP;
Abstract
A power controller controls a power of a laser emitted from a semiconductor laser device which includes a laser diode and an internal photodiode integrally assembled in a small substrate. The laser diode is electrically energized by an electric current power source, and the laser power is detected as a first electric current signal by the internal photodiode. An external photodiode detects the laser power as a second electric current signal. A feedback controller controls the power source on the basis of one of the first and second electric current signals. The controlling of the power source by the feedback controller is based on the second electric current signal when the operation of the external photodiode is proper and normal. The controlling of the power source by the feedback controller is based on the first electric current signal when the operation of the external photodiode is improper and abnormal.