Variable refractive surface

摘要

An optical element ( 200; 300 ) for providing a variable refractive surface. The element comprises a chamber ( 215 ) defined by at least one side wall ( 270 ), with an optical axis ( 90 ) extending through the chamber ( 215 ). The chamber ( 215 ) contains a first fluid ( 220 ) and a second fluid ( 230 ) in contact over a meniscus ( 225 ) extending transverse the optical axis ( 90 ). The perimeter of the meniscus ( 225 ) is constrained by said side wall ( 270 ). The fluids ( 220, 230 ) are substantially immiscible and have different indices of refraction. A first electrowetting electrode ( 242; 243 ) is arranged to act on at least a portion of the meniscus perimeter constrained by said side wall ( 270 ). A second electrowetting electrode ( 280 ) extends through the meniscus ( 225 ).