Research on Ultra-thin Mirror Fabrication and Demonstration of O500mm Ultra-thin Mirror

摘要

If an ultra-thin mirror with 2-4mm thickness is applied on deployable space optical system, the mass of the system can be decreased while its diameter increasing, and the mirror surface active adjust is achievable. The advantage of the ultra-thin mirror compared with traditional light-weighted mirror described above make ultra-thin mirror a strong competitor for next generation space optical system. Many important institutions have researched on fabrication of ultra-thin mirror. Contrary, the advantage of ultra-thin mirror application is just the disadvantage in the process of fabrication. Because of the ultra thin thickness, large distortion will be caused by the pressure of grinding and polishing. Also, the distortion caused by temperature alteration and stress can not be ignored. These will all affect the precision of the surface and increase its fabrication difficulty. The factors will possibly cause surface distortion and relevant control method in the process of fabrication and measurement are discussed in this article. ?195mm and ?340mm ultra-thin mirror fabrication experiments are carried out and ameliorations of fabrication technology are summarized form these experiments. Finally, a ?500mm ultra-thin mirror has fabricated and the experiment of active adjust indicates that this mirror can achieve acceptable surface quality.