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:
Apr. 16, 1991
Filed:
Jul. 21, 1989
Tomiyuki Numata, Tenri, JP;
Takashi Iwaki, Nara, JP;
Kunio Kojima, Nara, JP;
Toshihisa DeGuchi, Nara, JP;
Sharp Kabushiki Kaisha, Osaka, JP;
Abstract
A semiconductor laser driving apparatus for supplying a driving current to a semiconductor laser device of an optical disk recording and reproducing system, the level of which is changed to adjust the optical output of the laser device to one of plural levels corresponding to positions of an optical disk which is irradiated by a laser beam emitted from the laser device. The apparatus comprises: a current source for sequentially supplying plural reference driving currents having a different predetermined level to the laser device; a monitor for detecting the optical output level of the laser device when each of the reference driving currents is supplied to the laser device; a setting device for setting several optimum values on the basis of the detected optical output levels; a selecting device for selecting one of the several optimum values, depending upon the position of an optical disk where is to be irradiated by a laser beam; and said current source for supplying a driving current for recording information on an optical disk, to the laser device, the level of the driving current corresponding to the selected optimum value.