Dielectric-elastomer-based fabrication method for varifocal microlens array.

We report on a method to fabricate a varifocal microlens array that employs a dielectric elastomer (DE) sandwiched between two electrodes as the lens material. The microlens array is patterned on the electrode plates, and when the electrodes are subjected to a controllable operating voltage, the DE material is "squeezed" by the Maxwell force to deform the lens array pattern, thus resulting in curvature deformation yielding a tunable lens profile. The tunable focal length performance ranges from 950 mm to infinity. When compared with liquid-filled lenses, solid-based varifocal lenses are more robust to thermal expansion, gravity, and vibrational motion. Our approach can be utilized in applications such as machine vision systems.