Study On Processing Technology Of ZnS Crystal

So far, with the rapid development of military optical instruments, infrared (IR) optical material--ZnS was widely applied in IR optical systems. In this paper, a35mm diametric ZnS crystal was used as an example, on the base of the CCOS technology and the Preston theory, to briefly introduce the crafts of the ZnS crystal’s grinding process and critically discuss ZnS crystal’s polishing technique. By comparing various polishing powders and layer materials, the author found the best craft matching condition on the numerical control polishing process of ZnS crystal. Besides that, the challenge of how to control the ZnS surface finish is also further solved in this paper.After the testing by profilometer and Zygo detector, the ZnS-crystal aspheric surface figure can get0.2μm. the surface polish can achieve above the grade Ⅲ and the deviation of the center is less than1μm.All the parameters are to meet the requirements of an infrared tracking system.