| 摘要 |
PROBLEM TO BE SOLVED: To prevent a laser diode from being broken down by an excessive current without lowering an emission intensity too much. SOLUTION: The control circuit 102 controls a current supplied to a laser 101 so that the level of light emitted from the laser 101 may become constant. At each predicted timing, the error occurrence prediction circuit 103 predicts a first time period until the current value of a drive current supplied to the laser 101 by the control circuit 102 becomes a previously defined reference current value or more. When the first time period predicted by the error occurrence prediction circuit 103 becomes less than the previously defined reference time, the supply current adjustment circuit 104 increases the current value of a current supplied to the laser diode 101 at an increasing rate which causes the time period reaching the reference current value to be longer than that when the drive current is successively supplied by the control circuit 102. COPYRIGHT: (C)2011,JPO&INPIT
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