Patent ID: 7773489

Claim:
A liquid crystal lens element comprising: a first substrate; a second substrate disposed so as to be opposed to the first substrate; and a liquid crystal layer sandwiched between the first and the second substrates and configured to change focal point of light transmitted through the liquid crystal layer according to a magnitude of applied voltage to the liquid crystal layer, wherein on one of the surfaces of the first substrate, a first transparent electrode is formed and a concave-convex portion made of a transparent material and having a cross section of a saw-tooth shape or a saw-tooth shape approximated by steps is formed so as to form a plurality of annular shapes concentric around an optical axis of incident light, and on one of the surfaces of the second substrate, a second transparent electrode is formed, and at least one of the first and second transparent electrodes is divided into annular electrode segments, a dividing position of the at least one of the first and second transparent electrodes into the annular electrode segments agrees with dividing positions of the concave-convex portion of the first substrate into the annular shapes, and the annular electrode segments are each electrically connected with adjacent annular electrode segments via a resistive element.