Variable laser attenuator

摘要

A variable laser beam attenuator for typographical composing and printing machines is disposed in the optical axis of a laser light source emitting polarized light of only one polarization. A rotatable filter wheel having a plurality of absorption filters therein for obtaining a coarse adjustment is followed by a fine adjustment means comprising two plane-parallel glass plates disposed in a mutually symmetrically inclined manner in a holder for infinitely variable attenuation without deflection of the laser light beam. The inclination of the glass plates is selected such that the angle of laser beam incidence is approximately equal to the Brewster Angle. The holder is adapted to pivot together with the glass plates as a unit, about the optical axis.