US Patent 7808717 Apparatus for forming variable fluid meniscus configurations

Apparatus for providing a fluid meniscus with variable configurations by means of electrowetting. A fluid chamber (5) holds two different fluids (A, B) separated by a meniscus (14) of which the edge, having different sides, is constrained by the fluid chamber. A first electrowetting electrode (2a) is arranged to act on a first side of the meniscus edge and a second electrowetting electrode (2a′) is arranged to act separately on a second side of the meniscus edge. Selected meniscus configurations can be formed by providing selected voltages to the first and second electrowetting electrodes respectively.