INSTRUMENT FOR MEASURING OPPOSITE PLANE PARALLELISM

摘要

PROBLEM TO BE SOLVED: To measure the flatness and parallelism of opposite planes with high precision without requiring skillfulness and to enable application to automation. SOLUTION: This instrument is equipped with an interference optical system 18 which guides parallel light to a couple of measured surfaces M1 and M2 arranged opposite each other and guides an interference image formed by irradiating the measured surface M1 and M2 with the parallel light through mutually different optical paths C1 and C2 from the measured surfaces. On the interference optical system 18, a couple of opposite reference planes S1 and S2 are formed which have their parallelism and distance prescribed with high precision. A measuring head part 27 mounted between the measured surfaces is provided so that the reference planes S1 and S2 face the measured surfaces M1 and M2. Interference images generated by interference between lights reflected by the measured surface M1 and M2 and reference platens S1 and S2 facing them is picked up by image pickup means 19a and 20a.