Adaptive Micro-Lenses based on electro-wetting

In the past few years electro-wetting technology has become a promising approach for fabrication of lenses with adaptive focal length. By applying an electric voltage between a droplet and an electrode covered by an insulating layer, the surface free energy and thereby the contact angle is modified. At droplet dimensions below 1 mm the surface tension dominates over gravity, therefore a high optical quality of the liquid micro-lenses is guaranteed. We present a novel easy to fabricate micro-lens-system including a centring structure and fabricated in all-MEMS technology. With this system focal length tuning from 3 mm to infinity is achievable.