| 摘要 |
PURPOSE:To eliminate the need for a rotary mechanism and its driving device, etc., and to make a device small in size and simple by applying a voltage to each of electrodes in one of plural groups of electrodes and then forming a corresponding beltlike Fresnel transmissivity distribution selectively in a light transmission medium. CONSTITUTION:When the voltage is applied to one of transparent electrode groups 20, 22, 24, 26, and 28, a part under the transparent electrodes has optical anisotropy different from that of any other part, so the beltlike Fresnel transmissivity distribution, i.e. refractive index distribution is formed in a substrate. Consequently, a beam 32 emitted by a homogeneous light source 30 changes in light velocity at a part having a different refractive index while propagated in the substrate 16, so the beam 32 is converged on a position on a screen 34 corresponding to the transparent electrode group applied with the voltage. |
