Optical lens with electrically variable focus using an optically hidden dielectric structure.

Electrically variable gradient index liquid crystal lens is developed that uses flat uniform liquid crystal layer and electrodes. The spatial modulation of the electric field across the lens aperture is obtained by the modulation of the effective dielectric constant of an integrated doublet lens structure. The dielectric constants of two materials, composing the doublet, are chosen to be different at electrical driving frequencies, while their optical refractive indexes are the same, hiding thus the structure from the optical point of view. This "hidden layer" approach decouples the electrical and optical functions of that structure, increases significantly the performance of the lens and enables new functionalities. The technical performance and various driving schemes of the obtained lens are presented and analyzed.