| 摘要 |
PROBLEM TO BE SOLVED: To provide an ultrasonic variable-focal length lens array having no mechanical movable part and capable of adjusting a focal distance without requiring microfabrication, and a control method of the same.SOLUTION: Ultrasonic vibrators 2A, 2B, 2C, 2D are driven on a transparent flexural vibration plate 1. Thereby, a boundary face formed by a viscoelastic transparent film 3 covering at least one surface of the transparent flexural vibration plate 1 and a medium of the surface of the viscoelastic transparent film 3 is deformed to be made to function as a convex lens array surface at a plurality of locations on the transparent flexural vibration plate 1 according to a lattice-shaped vibration mode excited by flexural vibration of the transparent flexural vibration plate 1, and vibration strength of the ultrasonic vibrators 2A, 2B, 2C, 2D is controlled, thereby controlling the focal length of the convex lens array by the convex lens array surface. |
