Reduction in the interfacial tension between liquids for the low-voltage control of electrowetting cylindrical lenses

Abstract

A method to reduce the control voltage of an electrowetting double-liquid cylindrical lens was introduced and validated. We added a lower-surface-tension liquid to the original conductive liquid to reduce the interfacial tension between the two liquids and thereby reduce the control voltage. The control voltage of the electrowetting cylindrical lens could be significantly reduced using this method while ensuring the zoom range, as the initial curvature of the liquid interface and the refractive index difference between the two liquids changed little. Both the theoretical and experimental results helped prove the above conclusion. The surfactant was found to be the best low-surface-tension liquid, as it could reduce the control voltage by 47% as the focal length tended to infinity. Our study results can serve as a basis for the development of zoom lenses.