Research On The High-precision Absolute Measurement Of The Spherical Surface And Calibration Of Reference Surface

With the development of optical industry and optical imaging technology such as high resolution projection lithography and remote sensing technologies, higher accuracy of optical surface measurement is needed, especially higher accuracy of optical spherical surface measurement. Absolute spherical surface testing technology, which could eliminate the sysetem error such as reference surface error and higher accuracy of the surface profile testing, is effective methods for high-precision spherical surface measurement. In this article, two-sphere absolute surface testing method with three positions measurements based on spherucal phase-shifting Fizeau interferometer system and some related extension methods such as two-sphere absolute surface testing method with two positions measurements and two-sphere absolute surface testing method with five positions measurements are discussed.Error analysis is very important to improve the repeatability and the precision of surface testing, so the errors including PZT phase-shifting error, CCD error, spherical Geometry shape, The combined error caused by PZT, CCD and spherical Geometry shape, standard lens nonlinear error, light soure error, environmental error and alignment error are analyzed in details. On the basis of these erros analysis, the relationship between the errors and Interferometer structure parameters are discussed and the criterions to control the errors and some methods to minimize the errors are proposed.Some experiments are designed and analyzed, and these experiments are used to study the following contents:Repeatability and Testing accuracy of two-sphere absolute surface testing method with three positions measurements and two-sphere absolute surface testing method with five positions measurements; Repeatability of "cat’s-eye" measurement in two-sphere absolute surface testing method with three positions measurements; the contrast of calibration of reference surface between two-sphere absolute surface testing method with five positions measurements and spherical stitching. The inherent error of cat’s-eye measurement that is consist of standard lens nonlinear error and coma error introduced by alignment error in two-sphere absolute surface testing method with three positions measurements and five positions measurements is emphatically studied. The contrast experiment shows that with high-precision Interferometer and good alignment institutions, Absolute spherical surface testing technology can effectively calibrate reference surface and improve the precision of spherical surface testing.