Variable focusing power optical devices

Abstract

A variable focusing power fluid-filled lens or minor assembly () comprising a fluid-filled envelope and a supporting structure () therefor; the fluid-filled envelope being constituted by a first wall that is formed of a distensible elastic membrane () having an exterior optical surface () of variable focusing power, a second wall () that is spaced from the first wall on a z-axis which is generally perpendicular to the membrane, and a collapsible peripheral side wall () that extends between the first and second walls (), and being filled with a substantially incompressible fluid (); a membrane holding structure () that is attached to a peripheral edge of membrane for holding the membrane under tension, the membrane holding structure defining a plurality of discrete control points spaced around the peripheral edge of membrane where the position of the peripheral edge of the membrane relative to the second wall on the z-axis is controlled and permitting bending of the peripheral edge of the membrane between the control points in a plane defined by the z-axis and a tangent to the peripheral edge of the membrane; the plurality of control points including a plurality of dynamic actuation points; and an actuation mechanism for displacing the edge of the membrane on the z-axis relative to the second wall at each of the actuation points to control the shape of the membrane; wherein the actuation mechanism comprises a plurality of first cam members () that are connected to the membrane holding structure and associated with respective actuation points, a cam belt disposed circumjacent the membrane which comprises a plurality of spaced second cam members (), each second cam member being engaged with a corresponding one of the first cam members for controlling the position of the edge of the membrane on the z-axis at the respective actuation point, a cam belt support () that supports the cam belt for bidirectional rotation around the z-axis relative to the membrane and a coupling () for drivably connecting the cam belt to a selectively operable driver ().