Optofluidic varifocal lens actuated by dielectric elastomer sandwiched by two conductive liquids with different refractive indexes

To improve the focus tunability and reduce the difficulties in fabrication, we present a novel optofluidic varifocal lens actuated by dielectric elastomer sandwiched by two conductive liquids with different refractive indexes. The lens has a compact structure: two grid frames, two passive membranes, a dielectric elastomer actuator membrane, and two conductive liquids. Two cavities of the varifocal lens are filled with different conductive liquids. The conductive liquids are not only employed as the material of the optofluidic varifocal lens because of their high transparency but also work as the compliant electrode of the dielectric elastomer actuator membrane due to their conductibility. The results experiments show that the focal length variation of the lens is greater than 100%, the response time is approximately 75 ms. The lens is free from the compliant electrodeswhich greatly reduces the difficulties in fabrication.