| 摘要 |
PURPOSE:To enable light level controlling to be performed inexpensively by comparing the output of a photodetecting means and a reference level, and controlling the output of a counter circuit thereby fluctuating the laser driving signal from a laser controlling circuit. CONSTITUTION:A video controlling circuit 4 generates the video signal 4' corresponding to images, and a laser controlling circuit 5 emits a laser driving signal from this signal, thereby driving a semiconductor laser 1. The laser beam 1'' outputted on the side opposite from the recording laser beam 1' from the semiconductor laser 1 is received in a photodetecting circuit 2 and is compared with reference voltage 3' in a comparator circuit 3. A counter circuit 7 counts the monitor clock signals 4'' generated during nonscanning period from the video controlling circuit 4, by which the correction of the counter 7 is accomplished. The output of the counter 7 is converted to an analog signal by a D/A converting circuit 6, by the output thereof the output of the laser driving signal from the laser controlling circuit 5 is fluctuated, and the laser beam is adjusted. |
