| 摘要 |
PURPOSE:To simplify mechanism by attaching a lens which allows transmission of light and has elasticity to an annular supporting member having a piezoelectric characteristic to integrate and actuation or an ultrasonic wave oscillation. CONSTITUTION:The peripheral length of a toric supporting member 2 changes when a DC voltage is impressed between electrodes 3A and 3B on the inside and outside peripherals. The lens 1 having elasticity is consequently pulled outward or pushed inward, by which the thickness and curvature thereof are changed and the focal length is changed. The change in the focal length is corrected by changing electrically the focal length of the lens 1 in the above-mentioned way in order to correct the warpage of, for example, a disk of a device for reading out optically the information recording on the disk and reproducing sound or video, by which the focusing always onto the disk is made possible without moving mechanically the lens system. |
