Development of the micro rotary fan

This paper reports on the design and experimental evaluation of novel MEMS based rotary fans. Both flip-chip and solder self-assembled designs are demonstrated - each utilizing a scratch drive actuator (SDA) rotary motor with forward and reverse control at speeds up to 180 rpm. The SDA motor is powered using a sinusoidal 30-150 V0-P ac signal at frequencies from 2-15 kHz. Resonant mode vibration at 3 kHz allowed the fan motor to be driven using ac signals of less than 30 V0-P. The fan blades are rotated to a specific angle-of-attack using gold coated polysilicon bimorph structures or solder assembly mechanisms. The advantages to each assembly option are discussed with solutions applicable to many electromechanically coupled micro systems. The fabrication and assembly techniques used to create the MEMS fans are well suited for mass production for commercial applications. A versatile flow visualization technique for MEMS based gas flow actuators is also demonstrated using laser illuminated smoke particles introduced into a macro scale chamber containing the fan. (C) 2002 Elsevier Science B.V. All rights reserved.