Patent ID: 7839458

Claim:
A liquid crystal optical element comprising: a liquid crystal cell having a first transparent substrate with a first electrode, a second transparent substrate with a second electrode, and a liquid crystal layer encapsulated between the first transparent substrate and the second transparent substrate; and a power source unit supplying a voltage to the first electrode and the second electrode, wherein depending on the voltage applied between the first electrode and the second electrode by the power source unit, in-plane refractive index distribution of the liquid crystal cell changes, the first electrode is composed of a plurality of concentric electrodes concentrically arranged from a center of the first transparent substrate toward a periphery of the first transparent substrate, the plurality of concentric electrodes are grouped into at least two groups of concentric electrodes, among the concentric electrodes belonging to each group of concentric electrodes, the concentric electrodes that are adjacent to each other are connected through a resistor, and the concentric electrodes at each end of the concentric electrodes belonging to each group of concentric electrodes are connected to the power source unit through an extraction electrode, wherein an independent concentric electrode of a circular shape concentric with the concentric electrodes is further provided on the first transparent substrate, independently without belonging to any group of concentric electrodes, and the independent concentric electrode is connected to the power source unit through an extraction electrode, and wherein the independent concentric electrode is provided between a first group of concentric electrodes that is near a center of the liquid crystal cell and a second group of concentric electrodes that is near a periphery of the liquid crystal cell.