Stepwise Microactuators Powered by Ultrasonic Transfer

Eric Yeatman Optical and Semiconductor Devices Group, Department of Electrical and Electronic Engineering, Imperial College London, South Kensington Campus, Exhibition Road, London, SW7 2AZ, United Kingdom We propose a new way to deliver power to biomedical implants in order to address the higher energy requirements of microsystems with actuation functions such as drug release or mechanical adjustment of prosthetic devices. The method is based on ultrasonic power delivery, the novelty being that actuation is powered by ultrasound directly rather than via electrical form. The device consists of a mechanical oscillator which vibrates in response to incoming ultrasonic waves, and then converts these oscillations into stepwise motion of a mechanical actuator through oblique impact. Therefore, unlike conventional wireless power delivery or energy harvesting techniques, the proposed system is purely mechanical and does not include accumulation and storage of electrical energy or the conversion of energy from mechanical to electrical form, making it simpler and more efficient. © 2011 Published by Elsevier Ltd.