Apparatus and method for engraving with an electron beam

摘要

Apparatus and method for engraving with an electron beam such that depressions of different sizes can be generated in the surface of a workpiece and the different sizes of depressions are produced by an electron beam and wherein during periods when depressions are not to be formed the electron beam remains on but is defocused so that it does not form depressions. A modification of the invention provides that at times when the beam is not being used to cut depressions that it is pulsed wherein the short pulses of the beam which engage the work surface do not do any cutting.