Research On Error Sensitivity Theory And Desensitization Design Method Of Reflective Optical System

The final performance of the optical system not only depends on the theoretical design performance of aberration correction in optical system,but more importantly,it depends on the control of various factors such as optical elements position error,mirror surface parameters error,and system stability during the construction of the optical system.Reflective optical systems usually have parameter properties of large aperture and long focal length,and the mirror is generally designed with aspheric surface,the increased tolerance requirements will significantly increase construction period and economic costs.Therefore,it is of important theoretical significance and application value for optical design to carry out the research on sensitivity theory and desensitization design method of reflective optical system.Faced with the above problems,this paper studies the sensitivity theory and desensitization design methods of reflective optical systems,explores the influencing factors and laws of error sensitivity,and establishes the desensitization design methods of reflective optical system.This research provides theoretical and technological supports for the construction of reflective optical systems represented by large telescope and high-performance aerospace optical remote sensor.The main research contents of this paper are as follows:Firstly,a theoretical analysis around error sensitivity factors of the coaxial reflective optical system is conducted.It is proposed that optical path variation(OPV)is used as the evaluation parameter of the optical system error sensitivity.By means of geometrical optics,the analytical model of OPV caused by the error of the mirror position and surface parameters in the coaxial reflective optical system is established.The theory reveals the influence law of internal parameter error on the error sensitivity of optical system,and provides a theoretical basis for the establishment of desensitization design method of coaxial reflection optical system.On the basis of theoretical research on OPV,the error sensitivity evaluation function of reflective optical system is proposed.Comprehensive considering image quality evaluation,engineering design constraints and error sensitivity factors,a desensitization design method for coaxial reflection optical system is established.Using the desensitization design method,the coaxial reflective optical system of planetary atmospheric spectroscopic telescope(PAST)is designed.By calculating and analyzing the relationship between OPV and the wave aberration change in the desensitization design process of the optical system,the effectiveness of the desensitization design method of the optical system is verified.It shows that OPV can be used as an evaluation standard of error sensitivity in the design of coaxial reflective optical system.Based on the sensitivity error theory and the desensitization design method of coaxial reflective optical system,the error sensitivity theory is extended and applied to off-axis reflective optical systems the mathematical relationship between the offaxis magnitude characteristic parameters and the error sensitivity is constructed.Based on the evaluation function of OPV,a desensitization design method for off-axis reflective optical system is presented.Through the analysis of the relationship between OPV and the off-axis magnitude characteristic parameters of the optical system in the desensitization design process,the effectiveness of the desensitization design method for the optical system is verified,which shows that OPV can be used as the evaluation standard of error sensitivity to guide the design of off-axis reflective optical systems.The desensitization design method was applied to the design of offaxis three-mirror optical system of a large engineering project "Tianwen-1" highresolution imaging camera.In the case of the optical system parameters are basically determined,in order to further reduce the difficulty of optical element processing and optical system adjustment from the perspective of reflective optical system realization,two methods for desensitization design of reflective optical system for system realization are proposed: the method of manufacturing residual correction for free-form surface optical system and the method of multi-mirror integration design for off-axis reflective optical system which reduces the sensitivity of fabrication.In the former case,a quasi-planar freeform mirror at the exit pupil position of the optical system is used as an aberration compensation element to correct the residual error of the system at one time,which reduces the precision requirements of optical element processing and optical system assembly and adjustment.In the latter case,the primary mirror and the tertiary mirror of the off-axis three-mirror optical system are designed as one integrated mirror,which reduces the number of degrees of freedom,and reduces the complexity and sensitivity of the optical system.Theoretical analysis and design simulation show that the two desensitization design methods can effectively reduce the difficulty of optical component processing and optical system assembly.