Micromechanisms

Abstract

Micromechanics deals with micromechanisms which fall into two broad categories: sensors and actuators. Since sensors measure some property of their environment, internal sensor power dissipation should be minimized and sensor sensitivity must be maximized. In force sensing, power dissipation has been reduced by ten decades in twenty years. Sensitivity has been increased by twelve decades and is now being limited by thermal noise problems. Practical force sensing via mechanically resonant devices, which can be powered by unmodulated light and sensed by optical reflections, has been demonstrated and has major implications on future sensing systems. Actuators are devices which do work on their environment. The tool to produce microactuators is still a major problem. X-ray-assisted processing with very large structural heights satisfies most of the tool requirements for microactuators. It has been used, along with assembly, to produce magnetic actuators, such as rotational motors, with 120 µm rotors and rotational speeds of up to 150 000 rpm. A generic linear electrostatic actuator with large travel and large output force per unit chip area addresses practical markets for this evolving technology.