Curved reflector with adjustable focal length

摘要

A curved reflector of electro-magnetic radiation formed of an elastic, reflective membrane which utilizes a partial vacuum to provide the curvature to the membrane and an adjustable valve to vary such curvature, and therefore the focal length of the reflector. The valve comprises a central aperture in the membrane and a body adjustably mounted above the aperture with a flow restricting surface thereon which overlies the aperture.