Optical profilometer for surface roughness measurement with adaptive inclination adjustment and new type of detection system - has control system maintaining beam perpendicular to measurement surface, uses interferometric heterodyne detection

摘要

The profilometer has a control system which maintains a sensing beam perpendicular to a measurement surface . A controlled adjustment element causes a lateral displacement of the beam in an aperture (EP) as the matched transverse displacement is determined by comparing the spot position on two position sensitive detectors (PSD1,PSD2). Interferometric heterodyne detection is used. A reference beam carries one mode of a laser and an object beam the orthogonal mode. Both modes are guided to separate photosensitive diodes which produce the transverse displacement control signals. USE/ADVANTAGE - For measuring micro structures and roughness in surface measurement technology with minimal vignetting effects.