IMPROVEMENTS IN OR RELATING TO DEFORMABLE MEMBRANE ASSEMBLIES

摘要

A deformable membrane assembly 1 comprising a fixed support; a fluid filled envelope one wall of which is formed by an elastic membrane 8 that is held under tension around its edge by a flexible membrane supporting member 2 10 the membrane supporting member being coupled to the fixed support at a plurality of discrete control points 120 round the supporting member by respective engaging members for controlling the position of the membrane edge relative to the fixed support at the control points and the member being unconstrained between said control points; and a selectively operable pressure adjuster for adjusting the pressure of the fluid within the envelope thereby to adjust the shape of the membrane; wherein at least three control points are provided which are situated round the membrane edge at spaced locations on the member that are selected to increase the energy of the lowest order out of plane bending modes of the supporting member in response to loading through tension in the membrane that do not have a node round the whole supporting member. The invention further provides an article of eyewear comprising a deformable membrane assembly of the types described.