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:
Mar. 18, 1986
Filed:
Jan. 30, 1984
Shoji Yoshikawa, Tokyo, JP;
Masaharu Sakamoto, Tokyo, JP;
Olympus Optical Co., Ltd., Tokyo, JP;
Abstract
A light power controlling apparatus contains a semiconductor laser and a photosensor for receiving part of light emitted from the semiconductor laser to produce a corresponding electrical signal. The semiconductor laser is connected to first and second current circuits. The first current circuit averages a voltage signal based on the electrical signal of the photosensor by a first low-pass filter, thereby to have a detected voltage. The detected voltage is compared with a desired voltage by an error amplifier. The error amplifier produces a signal representing a difference between the detected voltage and the desired voltage. The difference signal is integrated by an integrator. According to the integrated signal, the first current circuit supplies a forward current to the semiconductor laser. The second current circuit is set at a peak power value in a modulating mode according to a voltage signal of a peak power setting member. The second current circuit supplies to the semiconductor laser a forward current according to a modulating signal, with superposing on the forward current of the first current circuit. The modulating signal is averaged by a second low pass filter. A voltage representing the product of the averaged value and the peak power value is added to the desired value. The sum voltage is then supplied to the error amplifier where it is compared with the detected voltage.