Study On Compensating Focusing For Space Hyper Spectral Imager's Force Optical System

In this paper, defocusing phenomenon of the hyper spectral imager's fore optical system is demonstrated. The factors inducing defocus are analyzed. And the research method, FEM and environment simulating tests to study the fore optical system's image waving rule are introduced. An research result is presented at the end part of this thesis, which mainly consists of the following points.1.The telescope's thermal deformation under several different temperatures is simulated via FEM method. The out coming thermal response is processed by optical-mechanical interface software. By doing that, the fore telescope system's fore optical system's thermal-optical properties are ensured and the predicted defocus amount is obtained.2.To fill the need for compensating focusing, a set of fine focusing system is designed and tested to be available.3.The whole fore optical system's thermal deformation is simulated via FEM method, and the deformation resultes are dealt with by interface software. The theoretical defocus and the relative compensating focus are obtained.4.Thermal-vacuum test is conducted to prove the defocusing rule. Thanks to the simulation results, it is easy to get the expected focusing amount under different temperatures. After some modifying, an focusing curve is presented by a mathematical expression.It is found that the relationship between defocusing and temperature is almost linear. Defocusing amount exceeds the allowable amount when the temperature difference is larger than 4℃, which would cause image resolution to decrease. It has to compensate for defocusing so as to guarantee the spectral imager's high performance.