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:
May. 21, 1991
Filed:
Sep. 20, 1990
Nobuo Miyairi, Fujino, JP;
Olympus Optical Co., Ltd., Tokyo, JP;
Abstract
This semiconductor laser driving apparatus for driving a semiconductor laser and to be used for an optical information recording and reproducing apparatus doing at least one of recording and reproducing information in an information recording medium by using a light from the semiconductor laser comprises an emitted light amount detecting device for detecting the emitted light amount of the semiconductor laser, an output controlling device for controlling the output of the semiconductor laser on the basis of the detected output of the emitted light amount detecting device so as to be kept constant, a driving device for feeding said semiconductor laser with an operating direct current, a high frequency superimposing device for superimposing a high frequency current on the operating direct current from the driving means, a measuring device for measuring the variation of the emitted light amount of the semiconductor laser with the variation of the operating current of the semiconductor laser in the absence of the information recording medium in the focus position of the semiconductor laser and a superimposed amount controlling device for controlling the superimposed amount by the high frequency superimposing device in response to the measured result of the measuring means.