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:
Dec. 17, 1996
Filed:
Jun. 21, 1994
Kazuyoshi Ishii, Tokyo, JP;
Makoto Hiramatsu, Kawasaki, JP;
Canon Kabushiki Kaisha, Tokyo, JP;
Abstract
In a magnetooptical recording apparatus, a light beam is radiated onto a magnetooptical recording medium while applying a bias magnetic field to the recording medium in such a manner that at least one of the light beam and the bias magnetic field is modulated according to an information signal. A current to be supplied from a DC power supply to the bias magnetic field applying device is switched by a switch element. The current switched by the switch element is smoothed by a smoothing circuit. The current to be supplied from the DC power supply to the bias magnetic field device is detected by a current detection element. A ratio between ON and OFF time periods of the switch element is changed in correspondence with an error between a value detected by the current detection element and a pre-set reference value.