Patent ID: 6295132
Filing Date: 2001-09-25
Classification: G01B,G01J

Abstract:
An interferometric measuring device for measuring shapes of rough surfaces of an object, comprising:a radiation generator emitting a short-coherent radiation;a changing device including a reflecting element for periodically changing a beam path and including a parallelly-displacing arrangement arranged in the beam path;a beam splitter forming a reference beam and a measuring beam, the reference beam being directed toward the changing device, the measuring beam being directed toward the object;a superposition element at which the measuring beam coming from the object and the reference beam coming from the changing device are made to interfere, forming interfered radiation;a photodetector receiving the interfered radiation; anda compensating grating arranged in a beam path of the reference beam upstream of the parallelly-displacing arrangement, the reference beam being diffracted at the compensating grating both prior and subsequent to passing through the parallelly-displacing arrangement.