| 摘要 |
PURPOSE:To obtain good-quality reproduced signals by irradiating either of the projecting parts or recessed parts of a recording medium having pregrooves consisting of the projecting parts and recessed parts with a laser spot of the frequency higher by the quantity which does not exceed the width of the recessed parts or projecting parts in both adjacent directions from the center of the projecting parts or recessed parts. CONSTITUTION:Laser beam pulses are formed by a modulating circuit 18 for a laser beam source and a circuit 19 for the laser beam source for heating the recording medium. An inverted magnetic field is impressed to the recording medium by a magnetic field impressing device 7 and the recording and reproduc ing of bits are executed by a head 4 for magneto-optical recording. A test is made to record signals of 3.7MHz on the medium under the conditions of, for example, 5.6m/s linear velocity, 10mW beam powder, and 100ns hours for irradiation with the beam at the time of executing recording in such a manner. Jitters are just 4.3ms at 1mW laser beam power for reproducing as a result of the test made to record 3.7Hz signals under the conditions of 5.6m/s, 10mW and 100ns hours in the same manner by wobbling the beam 0.2mum in the inner and outer peripheral directions from the center of a recording part. |
