Our earlier work in miniaturizing ultrasonic motors (8 mm dia. x 3 mm tall), produced power densities double that of human muscle. In addition, we integrated sol-gel ferroelectric thin films into a silicon micromachining process to demonstrate microfabrication of these low-speed, high-torque motors.
More recently, we have investigated the use of ferroelectric materials in power devices -- specifically, voltage step-up transformers that are electromechanical rather than electromagnetic. Power is acoustically transformed from one voltage and current level to another through a vibrating structure by using the direct and converse piezoelectric effects. A piezoelectric transformer can be thought of as a piezoelectric motor and piezoelectric generator combined into a single structure. The result is thinner, simpler and cheaper power supplies.
In this talk, I will discuss scaling, modeling and implementation of a prototype piezoelectric transformer (16 mm x 6 mm x 0.25 mm) which exhibits a voltage step-up of a factor of 175. I will also demonstrate application to an inverter for driving a cold cathode fluorescent lamp for a liquid crystal display back-light, and highlight possibilities for microfabrication.
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Modified: Jun 24, 1997|
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