METHOD AND APPARATUS FOR MULTI-PULSE FORMATION OF HOLES IN PRINTED CIRCUITS BY LASER BEAM Russian patent published in 1994 - IPC

FIELD: mechanical engineering. SUBSTANCE: check pulse is applied to hole being made immediately after each machining pulse, and progress in hole making is determined according to an increase in reflected radiation from copper substrate underlying printed circuit. Device for carrying out the method includes laser, modulator containing disk and motor, optical passage with rotatable mirror and lens, a system of mirrors and laser beam splitter, comparator, beam power meter with threshold arrangement, and gate of the optical passage connected to the threshold arrangement. Disk of the modulator has mirror surfaces at either side which are optically connected through an additional mirror system, and a splitter with an optical passage. EFFECT: increased accuracy of machining, improved quality of holes. 2 cl, 2 dwg