Patent ID: 7724444

Claim:
An optical element for providing interfacial waves by means of electro wetting, the optical element comprising: a fluid chamber, the fluid chamber including a first fluid and a second fluid which are separated by an interface, the fluids being immiscible, a first electro wetting electrode and a second electro wetting electrode, the first electro wetting electrode being separated from the first fluid and the second fluid by an electrically insulating fluid contact layer, the first electro wetting electrode being a singular annular insulated electrode forming a capillary tube extending around the periphery of the fluid chamber, the second electro wetting electrode acting directly on or being capacitively coupled to the first fluid, and a voltage control system for varying a voltage difference between both electro wetting electrodes in time to create interfacial waves at the interface between the two immiscible liquids, wherein said interfacial waves comprise one of standing waves or running waves with tunable amplitude and wavelength.