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. 04, 1997
Filed:
Jun. 20, 1995
James J Appel, Rochester, NY (US);
Aron Nacman, Penfield, NY (US);
Xerox Corporation, Stamford, CT (US);
Abstract
The present invention presents an apparatus and method for efficiently and automatically monitoring and adjusting the power output of laser diodes used to provide the scanning beams in a ROS system. Light radiated from the back facet of the laser diode is directed onto at least a pair of back facet photodiodes. The photodiode outputs are proportional to the power output of the laser diode associated with the photodiode. The polarization of the laser diode back facet output is controlled so as to ensure that the only outputs from an associated laser diode is sensed by an associated photodiode. In one embodiment, a half wave plate is used to rotate the polarization of one of the laser diodes and in another embodiment optical fibers efficiently transmit light emitted from the back facets to the photodiode.