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:
Feb. 26, 2002
Filed:
Feb. 16, 2000
Toshio Kasai, Tokyo, JP;
Asahi Kogaku Kogyo Kabushiki Kaisha, Tokyo, JP;
Abstract
A deterioration sensing device comprises a laser diode (LD), a voltage-current converter supplying electric current to the LD to radiate a laser beam which is received by a photo-diode, and an APC circuit outputting electric voltage in accordance with the intensity of the laser beam sensed by the photo-diode. The voltage-current converter is controlled based on the electric voltage so that the intensity of the laser beam is kept constant. An LD deterioration circuit is provided with a comparator, in which the electric voltage is compared with a reference voltage. An LD deterioration control unit is provided in the LD deterioration circuit to output a deterioration signal when the electric voltage becomes higher than the reference voltage, so that an alarm, indicating that the LD has deteriorated, is output, and the electric current supplied to the LD is decreased.