White light interference measurement method and white interferometric measuring device

摘要

PROBLEM TO BE SOLVED: To solve the respective problems of a measurement error due to temperature drift, a measurement error due to a noise signal, and a case of constituting a multi-axis measurement channel.SOLUTION: A white interference measuring apparatus comprises: a non-interference two light flux formation part A which constitutes white light of two non-interference light fluxes as P polarization light and S polarization light; a reference light path length scanning part B which varies light path length of reference light; an object measurement part C which forms two non-interference light fluxes after irradiation by measurement light reflected on a measurement object W and the reference light reflected on a measurement probe 36; an interference/non-interference route formation part D which forms an interference route 44 and a non-interference route 42 for the two light fluxes after irradiation; interference light formation means E for dividing the two light fluxes after irradiation into the measurement light and the reference light, converting the measurement light and the reference light to be the same polarization, and after that, forming the interference light by overlapping them; a detection part F which detects a light signal from an interference route 44 and a light signal from the non-interference route 42, respectively, takes difference between the light signals, and acquires only an interference signal with removed noise; and a calculation part G which calculates a position and deviation of the measurement object W from the interference signal with the removed noise.