Piezolectric actuator

Abstract

Abstract An ultra-sensitive actuator possessing substantial load carrying capacity and positioning range and which is capable of producing motions of 1 micro-inch or less with accuracy, which is thus especially adapted for supplying forces and displacements required to change the figures of mirrors and structural elements of optical equipment, such as, telescopes, including large space telescopes, optical polishing beds, mirrors for positioning devices, mirror deflection devices, mirror aspheric generators and electronic and optional tracking and positioning devices. The actuator includes a housing containing a piezoelectric stack consisting of oppositely oriented piezoelectric crystal discs arranged alternately in series to provide maximum expansion; a normally sealed chamber containing a liquid; a diaphragm dividing a portion of the housing containing the stack from the chamber, and an extensible housing end portion located at the end of the chamber disposed remote from the diaphragm. When a proper voltage is applied to the stack, it is extended to force the diaphragm into the sealed chamber for causing the liquid to exert a driving force against the extensible housing end portion for moving said end portion outwardly of the housing. An expansible bellows defines a part of the chamber and bears against the extensible end portion of the housing and together with the diaphragm amplifies the stack movement. Valves are provided for selectively trapping the displaced liquid for replenishing the liquid and for bleeding the chamber.

Inventors

• 👤 R Dame
• 👤 E Schmidt

Bibliographic Details