SURFACE MICROMACHINED MICROENGINE

The design, fabrication, and preliminary testing of a polysilicon microengine are presented. In this early work, electrostatic comb-drive actuation is used to demonstrate the microengine. However, the basic gear/link element of the microengine can be driven by any suitably forceful linear actuators. This device has direct application as a drive and power source for micromachined mechanisms such as optical switches, electrical switches, micropositioners, or any other micro-sized device requiring mechanical power. This is the first device of its kind that is directly linked to an output gear and converts linear motion from comb-drive actuators to rotational motion. The microengine provides output in the form of a continuously rotating output gear (approximate to 50 mu m in diameter) that is capable of delivering torque to a micromechanism. The microengine can be operated at varying speeds and its motion can be reversed. Processing considerations address the elimination of natural interferences that arise when conformally deposited polysilicon films form the links, joints, and gears that comprise the microengine. The resultant device is completely batch fabricated without the need for piece-part assembly.