Deformable Non-Round Membrane Assemblies

Abstract

A deformable membrane assembly comprises an at least partially flexible fluid-filled envelope, one wall of which is formed by an elastic membrane that is held around its edge by a resiliently bendable supporting ring, a fixed support for the envelope and selectively operable means for causing relative movement between the supporting ring and the support for adjusting the pressure of the fluid in the envelope, thereby to cause the membrane to deform. The bending stiffness of the ring varies round the ring such that upon deformation of the membrane the ring bends variably to control the shape of the membrane to a predefined form. The moving means comprise a plurality of ring-engaging members that we arranged to apply a force to the ring at spaced control points. There are at least three control points, and there is a control point at or proximate each point on the ring where the profile of the ring that is needed to produce the predefined form upon deformation of the membrane exhibits a turning point in the direction of the force applied at the control point between two adjacent points where the profile of the ring exhibits an inflection point or a turning point in the opposite direction.

1 - 33 . (canceled) 
     
     
         34 . A deformable membrane assembly comprising;
 an at least partially flexible fluid-filled envelope, one wall of which is formed by a distensible membrane that is held around its edge by a resiliently bendable supporting ring; and   a selectively operable adjuster for adjusting the pressure of fluid in the envelope to cause the membrane to deform;   wherein the bendable supporting ring comprises one or more sapphire ring elements.   
     
     
         35 . The deformable membrane assembly as claimed in  claim 34 , wherein the adjuster is configured to compress the envelope. 
     
     
         36 . The deformable membrane assembly as claimed in  claim 34 , wherein the adjuster is configured to expand the envelope. 
     
     
         37 . The deformable membrane assembly as claimed in  claim 34 , wherein the adjuster is arranged to act on the resiliently bendable supporting ring at one or more actuation points for active displacement of the supporting ring relative to a support. 
     
     
         38 . The deformable membrane assembly as claimed in  claim 34 , wherein the distensible membrane is continuously adjustable between an un-actuated state and a fully deformed state, and at each position between the un-actuated and fully deformed states the resiliently bendable supporting ring is displaced at the or each actuation point by a distance required to achieve a predefined form of the membrane. 
     
     
         39 . The deformable membrane assembly as claimed in  claim 34 , further comprising one or more hinge points, wherein the supporting ring is held stationary relative to a support. 
     
     
         40 . The deformable membrane assembly as claimed in  claim 39 , wherein the resiliently bendable supporting ring is free to bend passively relative to the support between the hinge points. 
     
     
         41 . The deformable membrane assembly as claimed in  claim 34 , wherein the resiliently bendable supporting ring comprises two or more ring elements, and the membrane is sandwiched between two adjacent ring elements. 
     
     
         42 . The deformable membrane assembly as claimed in  claim 34 , wherein upon actuation the membrane adopts a spherical form or a form defined by one or more Zernike polynomials Z j   ±k  (k≤j). 
     
     
         43 . The deformable membrane assembly as claimed in  claim 34 , wherein the supporting ring is formed with a protruding tab at the or at least one of the actuation points for engaging the supporting ring with the selectively operable adjuster. 
     
     
         44 . The deformable membrane assembly as claimed in  claim 34 , wherein the membrane is pre-tensioned on the supporting ring. 
     
     
         45 . The deformable membrane assembly as claimed in  claim 34 , wherein a reinforcing diaphragm is provided that is fastened to the supporting ring, which diaphragm has a greater stiffness in a plane of the supporting ring than in a direction of bending of the ring. 
     
     
         46 . The deformable membrane assembly as claimed in  claim 45 , wherein the reinforcing diaphragm is fastened to the supporting ring uniformly around the supporting ring so that a tension in the membrane is transmitted uniformly to the reinforcing diaphragm. 
     
     
         47 . The deformable membrane assembly as claimed in  claim 45 , wherein within the plane of the supporting ring, the membrane is longer in one dimension than it is in another dimension, and the reinforcing diaphragm has a lower stiffness in the one dimension than it has in the other dimension.