“…In the case of a membrane, the membrane may be used between liquid and air, or between two different liquids. While liquid lenses without a membrane generally rely upon electromagnetic or thermal properties of the liquids themselves in order to actuate the lens [8,9,10,11,12,13,14], liquid lenses formed with the addition of a simple membrane can be actuated through a much wider range of mechanisms. Thanks to the near-incompressibility of liquids, these lenses can utilize a variety of different actuators, including pneumatic [15,16,17,18,19], electrowetting [20,21,22,23,24], magnetic/electromagnetic [25,26], piezoelectric [27,28,29,30,31,32], electrostatic [33], dielectrophoretic [11,34], or any other actuator that can be coupled to a sealed liquid chamber to provide focus tuning.…”