Piezoelectric aperture size control device

Abstract

A piezoelectric aperture size control device for controlling aperture size consists of an electrically driven aperture-setting mechanism in which a diaphragm ring includes a plurality of aperture-setting blades or leaves and an actuating ring for opening or closing the blades disposed coaxially in a stationary ring leaving an annular space therebetween. A piezoelectric member is slidably disposed in the annular space and made to operably engage the actuating ring to urge the movements thereof in response to proper control signals. The piezoelectric member comprises first and second piezoelectric elements and a third piezoelectric element therebetween. The first and second elements are each disposed to distort and move in a radial direction when excited to become arrested within the said annular space. The third element, when excited, moves rotationally to cause the rotational movements of the first and/or second element when either is not arrested. The excitation voltages to the said elements are each time-related in a manner to cause the said piezoelectric member to move in a pre-determined direction in accordance with a pre-arranged design to change aperture size. It is understood that electrostrictive elements may be used in place of the piezoelectric elements in the operation of the device herein.

Dependencies are inferred from the claim text.