| 摘要 |
<p>In magnetooptic recording, this invention compensates for the change of temperature rise/drop characteristics of a medium in a heating/cooling process with rise/fall of a laser beam depending on a relative speed between the laser beam and the recording medium. This invention accomplishes a high recording density and high access performance as the advantages of a Z-CAV system, and improves reliability when a high density recording is made in a CAV system, too. Specifically, the relative speed of the laser beam to the medium, that is, the linear velocity of the medium is related to the thermal time constant of the medium to determine the thermal time constant τ at that linear velocity. Information to be recorded is converted to a binary signal, and the magnetooptic medium is irradiated with an intensity-modified laser beam according to the binary signal so as to record information. Information of thermal time constants relating to the temperature change of the magnetooptic recording medium due to the laser irradiation are in advance recorded in the magnetooptic recording medium. A clock frequency (f) is controlled so that T/τ, the ratio of the reciprocal T of the clock frequency (f) to the thermal time constant τ of the medium can be kept constant. The start and end positions of a mark can be accurately formed.</p> |
