| 摘要 |
PURPOSE:To record and erase exactly optical information by controlling an output of a semiconductor laser by two factors of an arrival temperature and a cooling speed by a heat transfer analysis with regard to a generation range of chlorosis recording and melanism erasion. CONSTITUTION:In case recording is executed under a condition that a revolving speed of a thin film 5 is constant, when a recording signal is received by a recording signal detector 1, a track position is detected by a track position detector 12, an output of a semiconductor laser 2 is determined by a laser output operator 14 and a pulse width is controlled by a timer 6, and a circular spot 4 is formed and recorded by a circular spot use optical lens 3. As for an operation of the operator 14, a material physical value is inputted, and an operation is executed by using a value I0 of the laser output which is set to the minimum value in a thin film material. Whether an arrival temperature Tmax exceeds a threshold value or not is decided, and when it exceeds the threshold value, whether a value of a cooling speed dT/dt to a melting point exceeds the threshold value or not is decided, and when it exceeds the threshold value, the laser output is set as a value in the track.
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