Parkhurst & Oliff
Method of processing information signal with respect to opto-magnetic record medium
 In a method of recording an information signal in an opto-magnetic record disc which has an easily magnetizable axis perpendicular to its surface, a constant erasing light beam and a modulated recording light beam are focussed by a single objective lens on adjacent tracks and an external magnetic field is applied to the record medium. The erasing and recording operations can be carried out at the same time by inverting the polarity of the external magnetic field track by track. 
Olympus Optical Co. Ltd.
G G
G11B G11B
inventional inventional
Tsuneo Kiichi
Yanagida Kato