Integrated Research On Opto-thermal Analysis And Imaging Analysis

Opto-thermal analysis is a method under comprehensive consideration with optics, structural mechanics and thermal effects. It is widely used in lots of optical instruments to regulate the heat of space optical system and thermal design. The star sensor modeled by finite element software is used to Opto-thermal analysis. We simulated the harsh environments to analyze the performance of the optical system and calculated the imaging quality changes in optical sotware. Nowdays Opto-thermal analysis method is widely used in space exploration. In stage of spacecraft design and manufacture on ground, it cost a lot to carry thermal regularity experiment. The Opto-thermal analysis method can save huge cost because it can reduce lots of heat balance experiment.The main research contents and results of this paper are as follows:1. Thermal and finite element theories are investigated. Basic heat transfer theories between the optical system and internal, external environment are researched. The progress of domestic and foreign research on opto-thermal analysis is reviewed and the problems that existed in opto-thermal analysis are summaried. Finite element theory and the application method on opto-thermal analysis is derivated.2. The surface fitting method is proposed. The surface of a lens will change differently when the optical system is in its thermal environment. The data of the deformed surface is discrete in Abaqus that Zemax cannot read these data directly. The surface fitting method translates the data to Zernike coefficients. Circle field standard Zernike polynomials, least square method and Schmidt orthogonal method are used in the surface fitting method.3. The method of irregular refractive index caused by heat is proposed. The temperature at different place of the optical system is different and the refractive index changes with temperature, so the refractive index in different place is also different. The characteristic that the ray travels in variable refractive index medium is discussed. The gradient surface is chosed to express the refractive index distribution. On this basis, we proposed the method of irregular refractive index on optical system.4. The vacuum tank test and Simulation of optical system is compared. The optical system’s vacuum tank test is carried out to verify the accuracy of the simulation. The thermal environment of the optical system is simulated, and the results of simulation are compared with that of the vacuum test.5. The effect on image quality is Analyzed. On the basis of evaluation index of the optical system, we calculated the effects caused only by thermoelastic deformation and that caused by irregular refractive index.6. The interface of softwares is created. The data should be extracted in finite element software with a code program, which need to creat to obtain the coordinate of the lens ’s suface. The coordinates are saved as txt style, and need be made coordinate transformation. For saving time, we created automatic data processing progra m and for the discrete data can’t be directly used to sequential ray tracing, we created a ZPL macro according the surface fitting method.