Self-Compensation of PZT Errors in White Light Interferometry

Abstract

One of main error sources in white light scanning interferometry is the inaccuracy of scanning mechanisms in that PZT (piezoelectric transducer) micro-actuators are preferably used. We propose a new calibration method that is capable of identifying actual scanning errors directly by analyzing the spectral distribution of sampled interferograms. This calibration provides an effective means of self-compensation for the non-linearity errors caused by PZT hysteresis, enhancing the measurement uncertainty to a level of 5 nanometers over an entire measuring range of 100 ㎛.