Single-Sided Contacting of Out-of-Plane Polarized Piezo Films for Fluid Membrane Lenses

We present an adaptive lens which tunes its focal length with a glass membrane that is deformed by an integrated piezo bending actuator. A particular challenge in the fabrication of this type of actuator is the need to contact the electrodes on both sides of the piezo element, i.e. also on the glass surface. Therefore, we show a novel contacting method where the top electrode on the piezo is segmented and the backside electrode is left at a floating potential. With this setup we achieve tuning capabilities of more than 13 dpt and response times in the range of less than 4 ms at a usable aperture of 4.5 mm.