Shape Measurement Of Grazing Incidence Mirror Based On Phase Measuring Deflectometry

Grazing incidence optical system is widely used in energy harvesting and imaging of soft X-ray.Profile accuracy of grazing incidence mirror is very important to the encircled energy of image point.This thesis presents the development of grazing incidence X-ray optical system.Aiming at the issues of shape measurement of grazing incidence mirror,the phase measuring deflectometry is studied.In this thesis,the measuring principle and technical composition,parameter model and calibration method,main error sources and influencing factors of phase measuring deflectometry are deeply and systematically analyzed.Based on the shape measurement of grazing incidence mirror,some technical links are improved and innovated.Binary fringe scanning and phase assignment are combined to realize the generation and acquisition of phase-shifting fringe image with high contrast,which avoids the non-linear transmission of the gray value of sine fringe and effectively improves the accuracy of phase calculation by DCT.LM algorithm is used to optimize the re-projection error to modify the system calibration parameters,which improves the accuracy of system calibration.The reconstruction method of Lagrange polynomials is improved to make it suitable for non-uniform mesh model.Compensation strategy is proposed to enhance the reconstruction ability of the algorithm for the surface with medium and high frequency information in the low sampling density region.Furthermore,the iterative model based on the non-uniform grid model is established by combining the compensation strategy.The optical path of shape measurement of grazing incidence mirror based on phase measuring deflectometry is designed in Zemax,the external parameter calibration strategy is established.And the reconstruction accuracy of grazing incidence mirror simulation with given structural parameters is 7.96e-03 ?m.The simulation results verify the feasibility of phase measuring deflectometry to measure the profile of grazing incidence mirror.The algorithm set out in the present thesis is applicable to the shape measurement of the ring inner surface profile of super paraboloid grazing incidence mirror,which can improve the reconstruction accuracy of grazing incidence mirror.According to the simulation model,the experimental device of phase measuring deflectometry to measure the grazing incidence mirror is built.And the shape measurement experiment of grazing incidence mirror is carried out,the PV value of the deviation between the reconstructed surface and the design value is 9.7943 ?m.The error of measurement results is not only the deviation between the actual shape and the design value,but also related to the calibration of LCD display screen,the acquisition of phase information and the limitation of the algorithm itself.Suggestions for improvement are given in this paper.