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. 18, 1990
Filed:
Feb. 29, 1988
Yoshiro Yoda, Tama, JP;
Olympus Optical Co., Ltd., Tokyo, JP;
Abstract
The bias magnetic field abnormality detecting apparatus is used in a photomagnetic recording and reproducing apparatus for recording information on a recording medium or for reproducing and erasing the information from the recording medium and is provided with a field magnetic coil generating a magnetic field in the reverse direction at the time of recording and erasing information but generating no magnetic field at the time of reproducing information. A magnetic field detecting circuit detects the polarity of at least the magnetic field of the field magnetic coil and detects whether the magnetic field is abnormal or not. A writing in protecting circuit prohibits the recording and erasing operations by the output of the magnetic field detecting circuit.