A COMPACT AND QUICK-RESPONSE DYNAMIC FOCUSING LENS

A dynamic focusing lens with a completely new mechanism that can be mi niaturized and allows for a quick-response has been developed. This le ns is structured to directly transform the lens shape as a crystalline lens of the human eye. The lens is comprised of two thin glass diaphr agms as a refracting surface, with a transparent working fluid sealed between them, and a new type of piezoelectric bimorph actuator. The di splacement of the actuator is enlarged by the bimorph structure. The g enerated force is determined by the layer number of the bimorph cells. When the actuator is driven to push or pull the glass diaphragm at th e actuator side, the other glass diaphragm is transformed into a lens shape (convex lens or concave lens) having various curvatures. The foc al length of the lens is controlled by the applied voltage to the actu ator. The dynamic focusing lens shows quick response up to 150 Hz. Whe n the lens is operated over 60 Hz, human visual perception cannot reco gnize the change of the focal length, and we can observe many images h aving different focal lengths simultaneously. (C) 1998 Elsevier Scienc e S.A. All rights reserved.