Thin varifocal liquid lenses actuated below 10V for mobile phone cameras

This paper describes the Wavelens technology: a new type of varifocal liquid lenses actuated by electrostatic parallel plates. The main technological steps involved in the fabrication process are discussed and the influences of the membrane material, the electrode size and composition (rigidity and stress) on the optical performance are evaluated in detail. The varifocal lenses were characterized extensively using wave-front measurements. Optical powers of 11m(-1) at 9V (16m(-1) at 10V) are measured on lenses with optical diameters of 3mm. The influence of the electrode size on the optical power is analyzed giving basic design rules for the device performance optimization. No significant optical quality degradation was observed with a low wave front error (<0.15 mu m) measured on the varifocal lenses.