| 摘要 |
PURPOSE:To obtain a variable focus lens which can largely change a focal length at a high speed by providing piezo-electric materials consisting of transparent films which are stretched in parallel with each other in the aperture of a container and have stretchability in the central part to permit transmission of light and liquid which is hermetically filled by the piezo-electric materials in the container and allows the transmission of light. CONSTITUTION:The piezo-electric films 2a, 2b constituted of, for example, a ceramic piezo-electric material, are stretched in parallel in the apertures at both penetrated ends of the toric container 1. Holes which allows transmission of light are opened at the center of these piezo-electric films and the transparent films 4a, 4b are stretched therein. The inside of the container 1 is hermetically closed by these films and the high refractive index liquid 5 is filled therein. The transparent films 4a, 4b are so stretched as to be flattened to a plane in the state of impressing a voltage to the electrodes 3a, 3b of the piezo-electric films 2a, 2b by using a power supply 6. Then, the volume in the container decreases and the films 4a, 4b change to a projecting shape when the electric field is made zero. The liquid 5 in the container acts and the container 1 has the effect of a lens when light is entered through the films 4a, 4b in the container 1. The lens which largely changes the focal length at a high speed is thereby obtd.
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