LICHTELEKTRISCHE POSITIONSMESSEINRICHTUNG.

摘要

Two identical transparent diffraction gratings (2,2') are set a fixed distance apart. A collimated light source (7), e.g. an i.r. laser diode, produces a beam which impinges on one grating (2) at an angle (alpha) producing diffracted rays (3,4) with constant phase difference (theta) to reach a transparent Diffracted rays (6,7) intersect at the grating (2'). When one grating (5) is moved in one direction (X), rays (6,7) undergo a relative phase difference phi = 2 pi.X/g. The pairs of diffracted rays (8, 9), (10,11) then exhibit interference patterns and are measured in photoreceivers (12,13), whose current changes are related to movement X by equations solved by processing equipment.