Patent ID: 7464547

Claim:
A thermal actuator for micro mechanical or micro electro-mechanical devices, the actuator including: a) a supporting substrate, b) an actuator extension portion, c) an anchor block extending from the substrate d) a first group of at least two elongate corrugated arms attached at a first end thereof to a heating circuit at the anchor block and at a second end to the extension portion, the first group being arranged, in use, to be conductively heated through connection to the heating circuit, e) a second group of at least two elongate corrugated arms attached at a first end to the anchor block and at a second end to the extension portion, the second group not being connected to a heating circuit and being spaced apart from the first group, wherein the corrugations of the corrugated arms of the first group project from the plane of the extension portion in a direction opposite to a direction in which the corrugations of the corrugated arms of the second group project, and the first group is arranged, in use, to undergo thermal expansion, thereby causing the actuator to apply a force out of said plane to the extension portion.