Electrically tuneable lenses made of electromechanically active polymers

Electrical control of optical focusing is important in several fields, such as consumer electronics, medical diagnostics and optical communications. Tuneable lenses are studied as possible alternatives to complex, bulky and expensive state-of-the-art approaches based on shifting constant-focus lenses. Among the actuation mechanisms investigated to possibly control the shape of liquid-based lenses, dielectric elastomeric actuators (DEAs) have shown promising features in terms of focal length variation and stability, fast and silent operation, compact size, low weight, shock tolerance, low power consumption and no overheating. Here, we propose a novel approach for the design of fully-polymeric DEA-based tuneable systems where the lenses are in the solid, rather than liquid, state. This expects to lead to several benefits: reduction of the temperature dependence of the lens’ refractive index, avoidance of any dependence on gravity and vibrations, and overcoming of problems associated with the need for preventing liquid leakage. In addition, the proposed design approach allows for using a single membrane DEA (rather than two), thus halving the required driving voltage. Furthermore, the proposed architecture shows more versatility for optical design. We present here ongoing development of this new type of tuneable lenses.