A High Precision 2-D Angle Measurement Interferometer

摘要

Fourier transform method and phase shift method are widely used to analyze fringe patterns to obtain surface profiles. In these ordinary fringe analysis methods, tilt or angle in the measured surface is often cancelled by certain operations. On the other hand, tilt can be considered as part of the measured surface, and obtained by fitting the measured surface profile with a line or plane. Therefore, we proposed a high-precision angle measurement method using fringe analysis techniques. In this paper, a 2-dimensional angular measurement interferometer based on a Mirau microscope objective is constructed to realize the proposed method, and the output curve of the measurement system is calibrated using a high-resolution autocollimator and a PZT driven lever system as the references. Fringe patterns obtained by the experiments are analyzed by both of the Fourier transform method and phase shift method, and the experimental results are compared with each other. Furthermore, the characteristics of the measurement system, including stability, resolution, and accuracy are evaluated and analyzed. Experiments verified that it could achieve both a wide measurement range of over +-2160 arcsec (+-0.6Degree) and a high angular resolution of 0.01 arcsec, simultaneously.