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:
Dec. 19, 1995
Filed:
Mar. 23, 1995
Naoto Inaba, Tokyo, JP;
Hiroshi Meguro, Yokohama, JP;
Nikon Corporation, Tokyo, JP;
Abstract
A laser drive circuit for modulating a laser beam intensity emitted from a laser device to a maximum power and a minimum power in accordance with a first and second values of a binary signal comprises: a photo-detector for detecting the laser beam emitted from the laser device to produce a detection output signal; a first differential amplifier for producing a maximum error detection signal representing a difference between the detection output signal applied thereto and a maximum reference; a second differential amplifier for producing a minimum error detection signal representing a difference between the detection output signal applied thereto and a minimum reference, a first sample and hold circuit for sampling and holding the maximum error detection signal at a timing of the first value of the binary signal and outputting the same as a maximum error signal; a second sample and hold circuit for sampling and holding the minimum error detection signal at a timing of the second value of the binary signal and outputting the same as a minimum error signal; and a laser drive amplifier for controlling the maximum power and the minimum power of the laser beam emitted from the laser device in accordance with the maximum error signal and the minimum error signal.