Non-aqueous organic solution based on a large-aperture spherical electrowetting liquid lens with a wide tunable focal length range

Abstract

A liquid lens, especially an electrowetting liquid lens, is filled with two immiscible liquids based on the electrowetting on dielectric effect. The chamber structure of the liquid lens is generally cylindrical or conical, and the filling liquids generally contain water. In this paper, a non-aqueous organic solution based large-aperture spherical electrowetting liquid lens (SELL) with a wide tunable focal length range is proposed. The spherical chamber can enlarge the contact angle range and the focal length range compared with the conventional cylindrical electrowetting liquid lens. The SELL has a low threshold voltage, high breakdown voltage, fast response time, and large zoom ratio with excellent image quality. Experimental results show that the non-aqueous organic liquids can avoid the generation of bubbles resulting from the hydrolysis phenomenon and still keep the lens working even when the dielectric layer fails. Furthermore, the imaging experiment shows that the focal length range can be tuned under different volume ratios of a conductive liquid to insulating liquid. The SELL can be applied in microscopes, cameras, telescopes, etc.