| 摘要 |
PURPOSE:To discriminate the type of a recording medium and to attain the stable recording, reproducing and erasing operations, by detecting the reflected or transmitted light of the light irradiated to a reflector or a transmitter which is provided to a recording medium and shows different reflection or transmission factors according to the type of the recording medium. CONSTITUTION:The laser beam delivered from a light source 2 is irradiated to a reflector 23 of a disk 7 prior to a recording, reproducing or erasing operation. The laser beam reflected by the reflector 23 is polarized by a polarized beam splitter 4 and supplied to a photoreceptor 10 to be converted into electric signals. Then a disk type detecting circuit 22 decides the type the disk 7. A laser modulator 14and a spindle motor control circuit 20 are controlled to the laser power and the revolving speeds optimum to the disk 7 by the control signal given from a controller 21. At the same time, the controller 21 sends the control signals to a focus/tracking control circuit 16 and a demodulation circuit 15. Then an optical head 1 is shifted for start of operations of record, reproduction and erasion with high stability.
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