Being spread the light beam in the light beam control

摘要

PROBLEM TO BE SOLVED: To eliminate unstable operation caused by interruption during a control process to correct the optical axis displacement of a light beam.;SOLUTION: This light beam control device 13 leads the light beam reflected by a drive mirror 131 for correcting the optical axis of light beam by branching it to obtain a beam spot position signal and a light intercept power signal, and input them in a beam position controller 136. The beam position controller 136 finds a difference from a target value for optical axis alignment by the beam spot position signal and a subtractor 21, multiplies it by a feedback gain K by an amplifier 22, and sends it to a multiplier 23. Meanwhile, the light intercept power signal is compared with a threshold value by a comparator 24, and if it exceeds the threshold value, "1" is added to the multiplier 23 to integrate the output from the amplifier 22 by an integrator 25, and it is output to the drive mirror 131 as a displacement command value. If it is less than the threshold value, "0" is given to the multiplier 23 to make an input to the integrator 25 zero, and an output right before the light beam is interrupted by the integrator 25 is maintained.;COPYRIGHT: (C)2009,JPO&INPIT