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. 19, 1991
Filed:
Sep. 18, 1989
Erwin R Wechsler, La Crescenta, CA (US);
Xerox Corporation, Stamford, CT (US);
Abstract
A circuit used in laser scanners which allows the continuous calibration of a laser so that the output power of the laser is accurately modulated by the input video signal regardless of temperature changes or aging effects of the laser. The video signal includes a test segment which has two steps. The light output of the laser is measured during both steps. The lower step measurement is compared to a reference and the error is used to adjust the bias current of the laser. The difference between the upper step measurement and the lower step measurement is compared to a second reference and the error is used to adjust the gain of the video signal so that the variation in laser power maximum and minimum remains calibrated.