A thermal
actuator for a micro-electromechanical device, especially a
liquid drop emitter for ink jet printing, is disclosed. The thermal
actuator comprises a base element and a movable element extending from the base element and residing at a first position. The movable element includes a
barrier layer constructed of a barrier material having low
thermal conductivity material, bonded between a first layer and a second layer; wherein the first layer is constructed of a first material having a high coefficient of
thermal expansion and the second layer is constructed of a second material having a high
thermal conductivity and a high Young's modulus. An apparatus is provided adapted to apply a
heat pulse directly to the first layer, causing a
thermal expansion of the first layer relative to the second layer and deflection of the movable element to a second position, followed by relaxation of the movable element towards the first position as heat diffuses through the
barrier layer to the second layer. Configurations of the movable element as a
cantilever, doubly-anchored beam and clamped plate are disclosed.
Diamond and
silicon carbide materials are well suited for use as the second material.
Titanium aluminide is a preferred material for the first material.