| 摘要 |
PURPOSE:To change the focal length of the lens by changing the refractive index, by constituting the lens with the transparent ferrodielectric substance and by controlling the voltage applied to the lens. CONSTITUTION:Transparent electrodes 4 are provided on the boundary face of transparent ferrodielectric substance 1 constituted with a prescribed curvature. The voltage of battery 2 is applied selectively to a pair of electrodes 4. When no voltage is applied to the lens, incident light beam 5 parallel with the optical axis is refracted as light beams 7 and 9; and when the voltage is applied, the refractive index of the lens is reduced, and light beam 3 is refracted as light beams 8 and 10 to generate focus F2. Consequently, the focus is moved to change the focal length according to presence or absence of the voltage. This invention is applied to the concave lens and the composite lens besides the convex lens of the figure. |
