Subaperture polishing of silicon asphere

Abstract

Subaperture polishing of silicon aspheric optics using air-inflated membrane tool is reported in the present work. A faster approach for material removal has been applied for local material removal using inflated bonnet polishing tool. Optical quality surface finish on silicon asphere is obtained by applying more pressure and greater velocity on subaperture tool with less distortion on the polishing surface as compared to a larger tool. Further, less tool wear cost makes this process more economical for lower production requirements. The linear feed rate has been optimized to produce optical quality surface finish using less number of iterations. Stylus profilometer and optical profilometer have been used for aspheric surface characterization. The surface accuracy and surface roughness achieved are 127 nm and 1.44 nm, respectively.