Focus tunable lenses

http://www.optotune.com/technology/focus-tunable-lenses

Optotune’s focus tunable lenses are shape-changing lenses based on a combination of optical fluids and a polymer membrane. The core element consists of a container, which is filled with an optical liquid and sealed off with a thin, elastic polymer membrane. A circular ring that pushes onto the center of the membrane shapes the tunable lens. The deflection of the membrane and with that the radius of the lens can be changed by pushing the ring towards the membrane or by exerting a pressure to the outer part of the membrane or by pumping liquid into or out of the container.

Working principle of Optotune’s manual lens ML-20-35, which achieves a lens shape ranging from concave to flat to convex. The ring that forms the lens is pushed towards the container, thus filling the lens with liquid

Optotune uses electroactive polymers (EAPs) as an electrostatic actuator for its series of laser speckle reducers. These so-called "artificial muscles" can undergo a large amount of deformation while sustaining large forces. While today's piezoelectric actuators only deform by a fraction of a percent, EAPs can exhibit a strain of up to 380%. There are different types of EAPs. Optotune has specialized in dielectric electroactive polymers (DEAPs) as described below. A detailed discussion on all types of EAPs can be found here.