A thin electrowetting controlled optical system with pan/tilt and variable focus functions

In this paper, we propose a thin optical device that has pan/tilt and variable focus functions for a small camera. Our optical device is composed of a tunable water prism and oil lens driven by electrowetting. The two functions are integrated, keeping the optical device thin. The oil lens is located inside the water prism and the two functions may be controlled individually or simultaneously by applying a voltage to electrodes patterned on a single flat plate. The total thickness of our optical device is 2.5 mm and it is capable of shifting the view direction 6.3 degrees and switching the focal length from 33.0 mm to 15.4 mm. The shape of the prism is estimated through a numerical simulation and is in accord with the experimental results. This paper opens a range of possibilities for the use of a multi-functional liquid optical device driven by electrowetting and the simulation and experimental results are useful for designing MEMS devices that have the liquid in contact with microstructures.