Air-coupled Piezoelectric Ultrasound Transducers for 3-D range finding
Current optical methods for 3D range finding and gesture recognition suffer from high power consumption, ambient light sensitivity and large size, which have limited their widespread adoption in mobile devices. Ultrasound is an attractive alternative to optical methods due to its potential for an integrated, low power, light insensitive solution. However, currently available bulk mode ultrasonic transducers suffer from inefficient coupling to air and their millimeter scale size makes them unsuitable for phased-array operation. Our research focuses on the development of micro-scale batch-fabricated piezoelectric micromachined ultrasound transducers (PMUTs) for use in a prototype 3D range finding system. In this talk I will present the techniques used in the development of aluminum nitride (AlN) PMUTs. I will present a multi-domain equivalent circuit model and finite element method simulations and discuss the effect of system level requirements on the transducer design. The fabrication process flow and the effects of variations in dimension and stress on transducer performance will be shown. Finally, I will present the characterization methods used in the electrical, mechanical, and acoustic domains and present the results for fabricated arrays.
Stefon E. Shelton received his B.S. in optical science and engineering in 2004 and M.S. in mechanical engineering in 2011 from the University of California, Davis. He has been a Graduate Student Researcher in Prof. David Horsley’s research group and at the Berkeley Sensor and Actuator Center. Research topics include modeling, fabrication, and characterization of piezoelectric MEMS transducers with a focus on Aluminum Nitride ultrasonic devices.
Date(s) - 01/23/2014
4:00 pm - 5:00 pm
1062 Bainer Classroom