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. 26, 1991
Filed:
Oct. 10, 1989
Hidetoshi Ikeda, Yokohama, JP;
Kabushiki Kaisha Toshiba, Kawasaki, JP;
Abstract
An information recording and reproducing device wherein bias power applied to a semiconductor laser is made larger by means of a switch circuit as the position of recording comes nearer to the outer circumference of an optical disc, and wherein the base potential of a transistor which is rendered operative in response to a recording signal is changed to keep the peak value of said recording signal unchanged even when the bias power is changed by the switch circuit, so that when not the peak power but the bias power supplied to the semiconductor laser is changed at every recording position on the optical disc in the radial direction thereof, the semiconductor laser can be prevented from becoming fatigued and the state of recording can be kept uniform at every recording position on the optical disc.