Coaxial Reverse Hartmann System Simulation Analysis And Digital Calculation

In the optical system,the non-spherical optics has many more degrees of freedom than the traditional spherical optics(such as the quadratic surface constant and the higher order coefficient).Compared with traditional spherical optical components,aspherical optical components have the advantages of simplified system structure,improved imaging quality,and improved aberration correction capability.Therefore,aspherical optical components have been widely used in high-precision optical systems.However,due to the normal aberrations in aspherical optical components,and the complicated measurement of the surface shape.Especially for large-diameter optical components,high-accuracy processing equipment,perfect processing,and matching inspection technologies are required to support high surface accuracy requirements.Due to its simple structure,high measurement efficiency,large dynamic range and low cost,the coaxial reverse Hartmann system is very suitable for the surface detection of aspherical optical components,especially large-diameter optical components,and analysis of low-frequency wavefront aberrations of mirrors.In view of this,this paper mainly studied the coaxial reverse Hartmann system,according to its basic principle created the simulation system,completed ray-centroid fitting calibration method,and detected the surface shape of the concave spherical mirror and the parabolic reflector based on this system.This paper is divided into the following sections:1、According to the principle of the coaxial reverse Hartmann detection system,using the real-time lighting technology Enlighten in Unity3 D software build the simulation system.Research on the related theories of this system,firstly,analyzed the common ray-centroid fitting calibration method(RCF).Based on this calibration,used ray-centroid fitting calibration method based on difference principle(RCF-D),and compared the results of these two calibration methods,which verified the feasibility and superiority of the fitting calibration method based on the difference principle.2、This paper designed the " coaxial reverse Hartmann system calibration and surface detection" simulation software was designed to simulate the process of RCF calibration and RCF-D calibration,analyszed error levels,used the Zernike polynomial to fit the wavefront and solved the Zernike polynomial coefficient matrix,used Matlab software to get fitting wavefront images.The software is easy to operate and has high efficiency.By inputting the relevant parameters of the experimental device,it can realize fully automatic mathematical calculation and obtain the reconstructed wave surface.3、Research on key issues such as the method for extracting spot center of mass,vector uncertainty,ambient light interference for coaxial reverse Hartmann system,proposed corresponding solutions.An axisymmetric concave spherical mirror(diameter is 76.2mm,radius of curvature R0 is 304.8mm)and an axisymmetric parabolic mirror(diameter is 76.2mm,focal length is 152.4mm)as the measured mirror,according to the calibration result of the system,the surface shape is solved,thus verifying the correctness of the detection principle.According to the solution of the fitting surface accuracy result,it proved that the accuracy of the detection system can meet the surface shape detection accuracy requirements of spherical and aspherical optical components in grinding and polishing processes.4、Analyzing the effect of distance measurement error,geometric calibration error,and spherical and aspherical mirror processing errors on the surface shape measurement results in the reverse Hartmann system.Through the simulation system quantitative control of the interference factors,analyze the impact of the error on the measurement results in order to achieve the error analysis in the actual measurement process.