Optimization of an adaptive PDMS-membrane lens with an integrated actuator

We present the first adaptive fluidic PDMS-lens system with an integrated piezoelectric pumping actuator. The system is fabricated in a highly streamlined fabrication process through casting using a hot embossing machine and the subsequent oxygen plasma bonding of the layers. With a shape optimized piezo actuator the achieved focal length ranges from 30 to 500 mm at a voltage from −9 to 44 V. We show that the lens resolution is crucially dependent on the thickness of the lens membrane. For an optimum thickness of 70 μm at 5 mm diameter the lenses achieve a resolution of 134 linepairs/mm (daperture = 2.5 mm) at a contrast of 50%.