Patent ID: 7710535

Claim:
A liquid crystal lens element comprising a pair of transparent substrates and a liquid crystal layer sandwiched between the transparent substrates and being configured to change focal point of light transmitted through the liquid crystal lens element according to the magnitude of applied voltage; wherein one of the pair of transparent substrates is provided with a phase correction surface constituted by annular portions arranged about an optical axis of the light and having a cross-section of concave-convex shape; a surface of the phase correction surface and a surface of the other one of the pair of transparent substrates are provided with respective transparent electrodes for applying a voltage to the liquid crystal layer; and between the transparent electrodes, a Fresnel lens surface having a rotational symmetry with respect to the optical axis of the light and a cross-section of saw-tooth shape or a cross-section of a saw-tooth shape approximated by steps and made of a transparent material, and the liquid crystal layer are provided.