| 摘要 |
PROBLEM TO BE SOLVED: To efficiently adjust the light emission without burdening a laser diode even when many zones exist. SOLUTION: The light emission at test powers of predetermined two points are successively instructed to light emission DA converters 136-144 by a light emission adjusting process part to emit the laser diode 100, and a subtracted current corresponding to test powers of two points is instructed to subtraction DA converters 146-150 to measure each power by a monitoring AD converter 152. From the result of this measurement, the relation with the instructed values for the optional powers on each DA converter is obtained by a linear approximation and registered on a power table 180. The decision of optimum light power by a trial writing is obtained in such a manner that the light power is gradually reduced from a start power to detect a critical power at the low limit side then a specified offset is added thereto. |
