Off-axis Aspheric The Ccos Processing Key Technology Research,

The optical manufacturing for off-axis aspheric mirrors has become increasingly challenging for two reasons. The mirrors, in addition to being larger, are more aspheric and off-axis in order to meet the requirement of next generation space camera, which is commonly configured as three-mirror-anastigmat (TMA) to get both wide FOV and high resolution, and the required accuracy is more stringent. This dissertation presents improved methods for both testing results analysis and aspheric mirrors fabrication concerning computer controlled optical surfacing (CCOS) technology to improve its efficiency and accuracy.A new CCOS model based on "relative tool path" is proposed, and a method is developed to solve and evaluate fabricating parameters. An optimizing arithmetic for calculating the best-fit sphere is also proposed, the result shows better accuracy is reached comparing to "three points method", from 107.8umRMS to 25.66umRMS.During interferometric optics test with null lens, "Nonlinear errors" of the testing coordinates will be introduced. A method based on ray-tracing, nonlinear fitting and coordinate transferring is proposed to eliminate these errors. "Misalignment error", which is caused by misalignment during null test adjustment, together with fabrication errors is shown in test results, and it is important to separate these two errors so that the test results can be used in CCOS process. ASIC software is developed for eliminating nonlinear error and separating misalignment error, and a high accuracy, suitable format data file is generated by ASIC for further analysis for CCOS process.In order to improve the ability of aspheric optics manufacturing, a new CNC machine named ASM is developed by CIOMP, and its numeric control system is presents in this dissertation. The new machine has ability to fabricate off-axis "mirrors up to lm dimension, and the accuracy can reach up to 1/50XRMS(A.=632.8nm). An on-line profilerometer is integrated in ASM, the error compensating model is presents. In order to make the new machine run better, ASM 1.0 software was developed. ASM 1.0 contains the entire CCOS process, including best-fit sphere calculating, profiler test and anslysis, virtual grinding and polishing, CNC grinding and polishing, etc.As results, the manufacturing process of a f/1.17, 770mm X 200mm rectangular even high order off-axis aspheric mirror is presented as an example in detail. Several test results of other ,nfF-axis aspheric mirrors are also given. All of the mirrors have accuracy better than 1/40X, and have fulfilled the demands by designer.