Antonelli, Terry, Stout & Kraus, LLP
Apparatus and method for recording/reproducing magneto-optical information
 A magneto-optical information recording/reproducing apparatus in which a magneto-optical information recording medium at least including a first magnetic film having perpendicular magnetic anisotropy, and a second magnetic film to which information recorded on the first magnetic film is transferred by irradiation of a laser beam, is used so that a readout laser beam is irradiated onto the second magnetic film to thereby readout the information transferred to the second magnetic film. The apparatus includes a 2-split detection circuit for receiving the readout laser beam reflected from the second magnetic film of the recording medium, and a subtraction circuit in which output signals of the two detection elements of the 2-split detection circuit are subtracted from each other to generate a differential signal. The apparatus further comprises a circuit for making a spot of the laser beam jump one track before readout of the information from the magneto-optical information recording medium, a positive/negative balance correction circuit for detecting an amplitude ratio between positive and negative side amplitudes in a track jump signal generated in the differential signal from the subtraction circuit in response to the track jump to thereby output a correction signal in accordance with the amplitude ratio, and an addition circuit for adding the correction signal to the differential signal to thereby generate a tracking error signal for tracking control used in readout of the magneto-optical information from the magneto-optical information recording medium. 
Hitachi, Ltd. Fujitsu Ltd. Olympus Optical Co., Ltd. Sanyo Electric Co., Ltd. Sony Corp. Sharp Kabushiki Kaisha Hitachi Maxell, Ltd.
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Takeshi Masaaki Michio Shigemi Satoshi Nobuhide Tetsu Hitoshi Yasuhito
Maeda Kurebayashi Matsuura Maeda Sumi Matsubayashi Watanabe Watanabe Tanaka