Patent ID: 7738344
Filing Date: 2010-06-15
Classification: G02B,G02F,G11B

Abstract:
1. A liquid crystal lens element comprising; a pair of transparent substrates opposed to each other; a liquid crystal layer sandwiched between the transparent substrates and configured to change a convergent point of light transmitted through the liquid crystal layer according to a magnitude of voltage applied to the liquid crystal layer; a Fresnel lens configured to switch between an on-state and an off-state by application of the voltage and having a rotational symmetry having a concave-convex portion formed on a flat surface of one of the transparent substrates opposed to the other transparent substrate and having a concave-convex shaped cross-section; a first transparent electrode formed on a flat surface under the Fresnel lens on said one of the transparent substrates on which the Fresnel lens is formed or on a surface of the concave-convex portion of the Fresnel lens; and a second transparent electrode formed on a flat surface of said the other transparent substrate opposed to said one of the transparent substrates, wherein the liquid crystal layer has a substantial refractive index n(V) which changes from a refractive index of the off-state at a time of no voltage application (V=0) to a refractive index of the on-state at a time of voltage application according to the magnitude of voltage V applied between the first transparent electrode and the second transparent electrode for extraordinarily polarized incident light, and the refractive index is ordinary refractive index n