MESSVERFAHREN ZUM BESTIMMEN EINES OBERFLAECHENPROFILS

摘要

Surface profiles are conventionally determined by means of stylus instruments, which require a mechanical contact between the measuring needle and the workpiece in order to scan the surface profile. For automation of the finishing operations, it is desirable to determine the surface profile without contact and without damage to the workpiece. To this end, the surface of the workpiece is illuminated, a reference beam is superimposed on the back-reflected light, this interference field is captured by a detector arrangement and used to derive dispersion components of a complex solid angle spectrum. The solid angle spectrum is retransformed locally and the phase variation above the place which gives the surface profile is determined. The invention proposes a homodynamic and a heterodynamic measurement method which differ in respect of the deviation of the reference beam and the structure of the detector arrangement. The local variation in depth of the surface profile can be resolved as finely as desired, and hence detailed information concerning the surface profile can be obtained, in particular by the heterodyne measurement method.