Verfahren und Messvorrichtung zur interferometrischen Abstandsmessung zwischen einem Messobjekt und der Messvorrichtung (A1)

Interferometric distance measurement - using incoherent or low coherent light taken from light source collimated and using first optical element imaged on pin hole with spherical wave fronts of beam led through hole converted to even wave fronts.

: Sowa, P.

Abstract
A 2nd optical element is used for converting the wave fronts. The light beam is then focussed by a 3rd optical element in the direction of the object (9) being measured. The light beam after passing the 3rd achromat is split in to a measuring and a reference light beam. The measuring light beam reflected at the object is again superimposed with the reference light beam. The optical path length of the reference beam course is so selected, that this is equal to the optical path length of the measuring beam course, for the object placed with its surface at the focal point. So that the measuring beam reflected at the object (9) and the reference beam in a returning direction, passes the 3rd and 2nd optical elements also the pin hole and then the 1st optical element. The returning measuring beam also the reference beam finally are supplied to a 2nd interferometer, in which after a new beam division, for the reference light beam, using an optical element, different length optical path distan ces are realized, corresp. to their distance from the optical axis, with the reference beam modified again by the superimposition of the measuring beam. The superimposed image is observed by a CCD camera. With recalibration and from the interference occurring, the distance of the object is decided. ADVANTAGE - Distance measurement between object and measuring system is achieved with smallest possible inaccuracy. System is small and compact.