(A) study on thickness optimization of inflatable circular membrane for large optical system

Abstract

This study focuses on the proper variation of thickness that makes optical surface profile being an ideal paraboloid in the inflatable structure for the large optical system. For the inflatable optical system, two circular membranes are joined together on their boundary and then the space between them would be pressurized: the optical system is inflated by applying pressure between the two membranes. The one membrane serves as the window through which the light can transmit and the other serves as the reflector that concentrates the light. Of the two membranes, the surface profile of the reflector must be controlled and the surface errors must be maintained as small as possible to have a good optical performance. In this study, the parametric study for the thickness of the membrane is firstly implemented. Here, it is assumed that the thickness is uniform. For this purpose, deformation of the membrane with pressure loading is simulated by the FEM. Using these results, optical properties of the membrane are calculated by the optical analysis. Further, the thickness of membrane can be varied from the center to the edge for better optical performance. The optimization of the thickness is performed to find out optimal variation of thickness in the membrane.