| 摘要 |
PURPOSE:To speed up erasing, recording and reproducing by making a device into such constitution that respective semiconductor lasers for the erasing and the recording, and for the reproducing are arranged, and control is executed through a sampling circuit and a comparator at the time of the erasing, the recording and the reproducing. CONSTITUTION:In an erase mode, a timing signal T2 comes to a high level at the time of address read, and a sampling hold circuit 26 samples the output of a low pass filter 24, and the output of the reproducing semiconductor laser 13, always in ON state, is controlled at a reference voltage Vref2, and in an erase area, the erasing recording laser 12 is lit together with the laser 13, and its output is controlled at the reference voltage, and the signals of the two lasers are inputted to the comparators 21, 22, and are compared with a reference value. At the time of the recording, the signal T1 comes to the high level, and the laser 12 is lit as well, and the output is controlled by the sampling hold circuit 25, and information is recorded by the ON/OFF of it. At the time of the reproducing, the laser 12 is turned off, and the output of the laser 13 is controlled. Accordingly, the output of the lasers 12, 13 are controlled, and the erasing, the recording and the reproducing can be executed at high speed. |
