EWOD-based variable-focus liquid lens

A variable-focus liquid lens based on EWOD (electrowetting on dielectric) has been developed. It comprises a top glass plate, a ground-electrode-involved bottom glass plate and a counter-electrode-involved cylindrical glass housing which contains two immiscible fluids of air and water with different refractive indices. By changing the applied voltage across the electrodes, we can tune the meniscus between the two fluids and focus length of the lens. The experimental results show that the prototype of the liquid lens could refocus on objects from 2 centimeters up to infinity away within 10 ms using a direct voltage within 40V