A Study On The Error Source And Calibration Method Of An Interferometric Optical Probe

In correcting aberration,high image quality and wide field of view,free-form optics is better than spherical and aspherical opticsAs wider application of free-form optics has been limited by the immature processing and detection technology,a new detection method is proposed to solve the problem of the detection accuracy and universality of complex freeform surfaces,which is combined by interferometric detection system and spherical shell lens.The detection light reflected from the free-form surface will be exit to different directions,but they can be collected back to the detection system by the inner surface of the shell lens.Therefore,each detected point on the free-form optics can be precisely longitudinal determined,and the spatial cloud point data of the surface is formed to realize the detection of the profile of the entire free-form surface.The possible error sources during actual detection is analyzed from mathematical model and simulation of ray tracing process of the optical probe,and after that classified by the mechanism of error.Combine the mathematical model to analyze the influence of different errors on the detection accuracy of the system,and calculate the error range that meets the accuracy requirements.A calibration method for errors that cannot meet the accuracy requirements is proposed,and the experimental process of calibration and eliminate the errors is simulated by software.The work in this paper includes three aspects:First,the basic structure of the interferometric optical probe system and the detection principle of the probe part is introduced.The system structure is built by Zemax,and the change of the interferogram that the measured surface deviating from the focus position is simulated,which explains the theoretical position accuracy of the measured surface could reach 20 nm.Second,a mathematical model of the probe part of the system is established.As the error sources are analyzed by the detection principle of the probe part and calculated by the mathematical model,tolerance range that meets the measurement accuracy is computed.Third,the installation method of the probe part and the measurement method of optical components is introduced.And after that,the errors are calibrated and the experimental methods are put forward.In this paper,the errors of the probe part were analyzed and calibrated only in principle.The analysis was based on the subject background of single-point positioning accuracy of 20 nm that obtained by theoretical research.The various interference and technical implementation methods in the process of building the system platform had not been considered,so there are many follow-up tasks need to be done to further reduce even remove the system errors.