Meniscus Pinned Variable-focus Liquid Lens Based on Electrowetting-on-dielectric

A novel configuration of variable-focus liquid lens based on electrowetting-on-dielectric technique is presented, which consists of a glass slide growing a conductive indium tin oxide (ITO) film and a hydrophobic dielectric film, a hollow conical metal ring suspended right above, a gap between the slide and the ring, and the lens liquid (water). By changing the voltage applied to grounded metal ring and the ITO control electrode, both the position and curvature of the liquid meniscus can be reversibly adjusted, thus tuning the focal length of the lens. The experimental results show that at a 40 V power supply, the liquid lens is able to focus on objects from 2.5 centimeters up to infinity away with a good imaging quality.