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:
Aug. 08, 1989
Filed:
Nov. 08, 1988
Kazuyuki Shimada, Tokyo, JP;
Isamu Shibata, Fuchu, JP;
Ricoh Company, Ltd., Tokyo, JP;
Abstract
A system for controlling the operation of a semiconductor laser is provided. In one aspect of the present invention, a switching element, which is turned on and off in accordance with a signal modulated with image information, is connected in series with the semiconductor laser for controlling the operation thereof. In another aspect of the present invention, a semiconductor laser control system includes a photodetector for detecting the intensity of a laser beam emitted from the laser, a comparator for comparing the detected intensity with a predetermined refence intensity, an up/down counter which changes its count depending on the result of the comparison at the comparator, and a laser driver which supplies a driving current to the laser as modified by the count of the counter. A reset circuit is provided to reset the counter when at least the laser driver is powered up with a predetermined supply voltage. In addition, the laser driver is so structured that the supply of the driving current to the laser is disconnected for a predetermined time period after the power up thereof.