LIQUID CRYSTAL LENS ELEMENT AND OPTICAL HEAD DEVICE

摘要

There is provided a liquid crystal lens element having a lens function capable of performing spherical aberration correction including a power component equivalent to a focal point change of the stable incident light in accordance with the voltage applied. One (12) of the two transparent substrates (11, 12) has a transparent electrode (15) and a Fresnel lens surface (17) while the other (11) of the two transparent substrates has a phase correction surface (18) and a transparent electrode (16). Thus, by arranging the Fresnel lens surface (17) and the liquid crystal layer (13) between the two transparent electrodes (15, 16), the substantial refraction factor distribution of the liquid crystal layer (13) is changed according to the voltage applied, so that positive/negative power is given to the wavefront transmitting through the liquid crystal layer (13), the Fresnel lens surface (17), and the phase correction surface (18).