Patent ID: 7029101

Claim:
A thermal actuator for a micro-electromechanical device comprising: (a) a base element; (b) a cantilevered element including a thermo-mechanical bender portion extending from the base element to a free end tip residing at a first position, the thermo-mechanical bender portion including the cantilevered element including a barrier layer constructed of a dielectric material having low thermal conductivity, a first deflector layer constructed of a first electrically resistive material having a large coefficient of thermal expansion, and a second deflector layer constructed of a second electrically resistive material having a large coefficient of thermal expansion wherein the barrier layer is bonded between the first and second deflector layers; the thermo-mechanical bender portion further having a base end and base end width, w b , adjacent the base element, and a free end and free end width, w f , adjacent the free end tip, wherein the base end width is substantially greater than the free end width; (c) a first heater resistor formed in the first deflector layer and adapted to apply heat energy having a first spatial thermal pattern which results in a first deflector layer base end temperature increase, ΔT 1b , in the first deflector layer at the base end that is greater than a first deflector layer free end temperature increase, ΔT 1f , in the first deflector layer at the free end; (d) a second heater resistor formed in the second deflector layer and adapted to apply heat energy having a second spatial thermal pattern which results in a second deflector layer base end temperature increase, ΔT 2b , in the second deflector layer at the base end that is greater than a second deflector layer free end temperature increase, ΔT 2f , in the second deflector layer at the free end; (e) a first pair of electrodes connected to the first heater resistor to apply an electrical pulse to cause resistive heating of the first deflector layer, resulting in a thermal expansion of the first deflector layer relative to the second deflector layer; and (f) a second pair of electrodes connected to the second heater resistor portion to apply an electrical pulse to cause resistive heating of the second deflector layer, resulting in a thermal expansion of the second deflector layer relative to the first deflector layer, wherein application of an electrical pulse to either the first pair or the second pair of electrodes causes deflection of the cantilevered element away from the first position to a second position, followed by restoration of the cantilevered element to the first position as heat diffuses through the barrier layer and the cantilevered element reaches a uniform temperature.