| 摘要 |
PROBLEM TO BE SOLVED: To continuously control power even in such system which continuously performs recording. SOLUTION: Return light in recording varies in the intensity of the return light by reflecting the state of recording marks. The recording level is detected by a difference in the intensity of the return light. The recording state can be well reflected by computing the ratio of the intensity of the return light at a recording start point and the intensity of the return light rear the recording terminal, not the absolute intensity of the return light. When a return light detector has a limiter in order to avoid saturation, the similar relation can be determined from the relation with the intensity of a front monitor. The recording state can be detected as well by viewing the intensity of the inner peripheries at three spots. |
