| 摘要 |
PURPOSE:To prevent erroneous recording and accidental erasure of an optical disk by making an electromagnetic wave irradiated onto the optical disk at reproduction of information as an intermittent wave. CONSTITUTION:The irradiated power of an irradiated light beams P10 to an optical disk 10 is intermitted at reproduction and the irradiated time and the non-irradiated time are repeated. Then the reflected light beams P20 of the disk 10 are made as an intermitted wave, then the irradiated power is set high, made incident on an optoelectric signal converter 300 as an output light P23 via an optical head 400 and an electric signal V20 is sent to a detector 500 under the control of a controller 100. An output signal V30 of the detector 500 is obtained by making the peak value of the electric signal V20 continuous based on the reflected light P20 of the irradiated light P10, and even when the integration value of the irradiated power of the irradiated light beams P10 is small, since the voltage V30 is obtained from a high peak value, the error in the recording/erasure is eliminated.
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