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. 13, 2003
Filed:
Aug. 04, 2000
Shoji Iwazaki, Tokyo, JP;
Pentax Corporation, Tokyo, JP;
Abstract
A semiconductor laser device comprises a semiconductor laser, a photo-diode, a first input terminal and a second input terminal. A sample hold circuit, having a first switch and a capacitor, is provided between the first input terminal and the semiconductor laser. A second switch is provided between the second input terminal and the semiconductor laser. A drive current is supplied to the semiconductor laser based on a light radiation level command signal input to the first input terminal. A constant current is generated based on a signal input through the second input terminal. In a sampling mode, the first and second switches are turned ON, and thus, a control current, which is obtained by subtracting the constant current from the drive current, is sampled by the sample hold circuit. In a holding mode, one of a bias current, obtained based on the control current and the constant current, or the drive current are supplied to the semiconductor laser, in accordance with ON/OFF of the second switch.