DISTANCE DETECTOR FOR LASER PROCESSING DEVICE

摘要

PROBLEM TO BE SOLVED: To improve reliability by measuring the distance without the influence of plasma and spatter even if they are generated during laser processing. SOLUTION: This distance detector 100 for detecting the distance related to a light condensing position and a workpiece 2 by using an electrostatic capacity C comprises; a detecting electrode 1 to form the capacity C in the interval to the workpiece 2; an input signal generating part comprising an alternating current voltage source 15 to generate alternating current signals to be input to the electrode 1 and a constant current amplification circuit 16; a signal detecting part comprising a voltage detecting circuit 8 to detect the alternating current signals generated between the workpiece 2 and the electrode 1; and a calculating circuit 21 to carry out the calculation by matching the frequency of the alternating current signal detected by the signal detecting part comprising the circuit 8 with that of the alternating current signals generated at the input signal generating part comprising the source 15 and the circuit 16.