Large in-plane displacement microactuators based on electro-thermal bimorphs with folded multiple segments

A mechanism for achieving large in-plane displacement is proposed, fabricated and tested. A key distinguishing feature of this mechanism is that it employs bimorph actuator beams, which have traditionally been used for achieving out-of-plane displacements only. A combination of rigid beams and bimorphs amplifies in-plane displacements and minimizes out-of-plane displacements produced by the bimorphs. A test structure with thermal bimorphs and an embedded resistive heater is fabricated; a maximum displacement of 135 μm is measured at just 3.8 V dc. The mechanism may also be implemented using bimorphs and multimorphs based on piezoelectric effect, electroactive polymers, shape memory alloys, magnetostriction, and electrostriction. Possible applications include movable MEMS stages, integrated Michelson interferometers, temperature sensors, and movable microneedles.