| 摘要 |
PURPOSE:To accurately detect the position of a laser beam by converting four AC voltages outputted from a quadruple division type laser beam position detector into DC voltages in proportion to the voltage and calculating the position of the beam based on the ratio of four DC voltages. CONSTITUTION:The laser beam 1 of a pulsed laser light is made incident on the quadruply divided light receiving surfaces 3 of the quadruple division (QD) type 2 and the outputted voltages VA-VD from the respective light receiving surfaces A-D are converted into the DC voltages by AC/DC conversion circuits 5 through output cords 4. Next, the respective outputted voltages VA-VD are inputted in an optical axis beam position calculator 6 to calculate output ratio VX and VY. The voltage obtained by converting the AC voltage from the QD type plane 2 into the DC voltage is the voltage to which offset correction is performed so that all the voltages become positive, which is used to calculate the output ratio VX and VY. Then, the relation of the output ratio VX and VY to the moving quantity of the laser beam is examined. By using the relation, the actual position of the laser beam is detected. |
