  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.
