Deformable mirror with pneumatic actuator pre-load

Abstract

In a deformable mirror having a mirror face plate and a plurality of axially movable piezoelectric actuators for controlling the contour thereof, an improvement is provided by which a pneumatic pre-load assembly is inserted between the face plate and the actuators. The assembly includes a core, having apertures therethrough, with a plurality of mirror surface contour posts passing separately through said apertures and a diaphragm plate which is mounted between the face plate and the core and spaced from such face plate but in contact with such core and one end of the posts. A rear plate is mounted to the other end of such posts and in spaced proximity with the core, which core, together with the diaphragm plate and the rear plate, define a cavity therebetween. The posts are aligned with actuators on the other side of the rear plate. Gas is applied to such cavity to bring the posts and the rear plate into contact with their associated actuators so as to pre-load them. A voltage is then applied to the piezoelectric actuators to increase their length against the pre-loaded rear plate and the posts to change the contour of the mirror face plate. Such pre-loaded rear plate tends to compress the actuators when the voltage is shut off so that by controlling the voltage, one can move the mirror surface contour back and forth as desired.

Dependencies are inferred from the claim text.