Laser beam cutting device for cutting PCB holes - has reflector arrangement ensuring uniform beam distribution over mask surface

摘要

Laser cutting appts. comprises a laser beam source (103) which passes through a mask (101) after being reflected within an area between the mask and a reflector (102). The reflector is located on the side of the mask nearest the laser source at an angle (Q) to the face of the mask such that the distance between the mask and reflection reduces along the direction (x). The angle (theta 1) is given by (Theta1)=(thetao)(RrxRn)n-1)/(Zn+1-(RrxRm)n) (where Rm is the reflector factor of the mask, Rr the reflection factor of the reflector, n the number of reflections between mask and reflector and theta the incidence angle of the light source on the mask). USE/ADVANTAGE - Laser cutting printed circuit board holes. The laser beam is uniformly dispersed over the whole surface of the mask and the energy loss between mask and reflector is minimised leading to more efficient use of the beam.