| 摘要 |
PURPOSE:To attain reproducing operation or confirming and reproducing operation with fixed reproducing power by controlling a preceding beam in correspondence to the detecting output of a front photodetector at the time of reproducing and controlling a following beam correspondent with a value, for which the detecting output of a rear photodetector is subtracted from the detecting output of the front photodetector at the time of recording or erasing. CONSTITUTION:At the time of reproducing, the reproducing operation is executed only by a preceding beam A. Then, the detecting output of a front photodetector 14 is regarded only for the single preceding beam A and the optical intensity of the preceding beam A is controlled in correspondence to the detecting output of the front photodetector 14. On the other hand, at the time of recording or erasing, in which two beams are simultaneously turned on, the two beams are simultaneously received in the front photodetector 14. Accordingly, not only a following beam B component is generated but the detecting output of the single preceding beam is generated in a rear photodetector 17. Then, the subtracted value of both outputs is obtained and defined as the detecting output corresponding to only the following beam B component and the optical intensity of the following beam B is controlled. Thus, the stable reproducing operation and confirming and reproducing operation can be executed. |
