Physicist and inventor, Bruno Berge, has created a liquid optical lens.
Using a process known as electro-wetting, a water drop is deposited on a metal substrate and covered by a thin insulating layer. When a voltage is applied to the metal, it modifies the angle of the liquid drop.
The liquid lens is comprised of two liquids, water and oil, one is a conductor while the other is an insulator. A variation in the voltage causes a change to the curvature of the liquid to liquid interface, which changes the focal length of the lens.
The use of liquids allows for low cost construction. There are no moving parts and electrical consumption is extremely low. The lens has a large inverse focal length range, quick response, high optical quality and can operate in a wide temperature range.