Hermetic sealing of liquid using Laplace pressure disparity induced by heterogeneous surface energy

A simple and novel hermetic sealing method for an electrowetting-based tunable lens is presented in this paper. The proposed method utilizes the Laplace pressure disparity (LPD) induced by heterogeneous surface energy intentionally prepared on a lens-cover glass. An amorphous fluoropolymer is a suitable material for inducing a large LPD because of its extremely low surface energy. The liquid lens sealed by the proposed method shows outstanding hermeticity as well as long-term stability against the generation and growth of bubble. Moreover, it provides high bond strength by preventing the adhesive used for bonding from coexisting with the lens liquid.