Research On Absolute Spherical Surface Testing Technology Using Optical Interference

With the development of optical industry and related field, higher accuracy of optical surface measurement is needed. Absolute surface testing can eliminate the error introduced by the reference surface and higher accuracy of the surface profile testing can be obtained.In this article, three-position absolute surface testing technology and some related technologies including two-position surface testing and five-position absolute surface testing are discussed. Six degree of freedom device with high accuracy is designed for three-position absolute surface testing technology based on Zygo interferometer. The alignment errors are analyzed in order to propose detailed requirements of the experimental methods and operating procedures.The related experiments of three-position absolute surface testing technology are designed and analyzed. The experiments are used to study the following contents:(1) Repeatability of three-position absolute surface testing; (2) Contrast of testing accuracy between three-position absolute surface testing and two-position surface testing; (3) Testing accuracy of three-position absolute surface testing; (4) Testing accuracy of five-position absolute surface testing. Zernike 2θerror caused by reference lens in the cat's-eye position is especially pointed out.Error analysis is very important to improve the precision of optical testing, so the errors during the three-position absolute surface testing are analyzed. The errors are divided into two aspects:errors caused by facts inside and outside the interferometer. The facts inside interferometer include:PZT,CCD,light source. Errors caused by facts outside the interferometer are mainly environmental perturbation errors such as air perturbation and vibration.