OPTICAL INFORMATION RECORDING AND REPRODUCING DEVICE

摘要

PURPOSE: To perform exact recording by means of a stable light pulse without complicating the circuit constitution of a detecting system for light output by setting a recording base current at the time of recording smaller than a reproducing current at the time of reproduction by means of a CPU. CONSTITUTION: A semiconductor laser 6 transmits a recording or reproducing laser beam and a D/A converter 2 and a V-I converter 5 supply a reproducing current Ia and a recording base current Ia-Ic to the semiconductor laser 6. A D/A converter 3, a V-I converter 9 and recording data part 10 supply a current for recording signal Ib to the semiconductor laser 6 and recording and reproduction of information are performed. Considering the temp. characteristic and the secular change of the semiconductor laser 6 at the time of recording, a CPU 1 sets a digital set value C so that the value of the base current Ia-Ic does not exceed the threshold current of a driving current at the time of starting to output the transmitted beam from the semiconductor laser 6.