Modelling of piezoelectric thin-film-plate devices

Titre : 
Modelling of piezoelectric thin-film-plate devices

Orateur:
Einar Halvorsen

Professeur à l'Université South-Eastern Norway en Norvège

Résumé : 

An electromechanical transducer based on a plate with a piezoelectric thin-film on top is a feature of several types of microscale devices such as pumps, lenses, resonators and ultrasonic transducers. In designing, optimizing and analyzing such devices, mathematical modelling is an indispensible tool. In this talk we will discuss a handful device examples and how we used modelling to gain insights. We will present a variational model for the geometrically nonlinear behaviour of the piezoelectrically actuated MEMS tunable lenses. Residual stresses during fabrication and larger actuation voltages cause large deflections such that a linear model becomes insufficient.  The model succeeds in fitting measurements when used in a constrained optimization scheme to determine the layers’ residual stresses and the piezoelectric coupling coefficient. Next, we show how finite-element modelling together with a compact, fiber-based interferometric setup can be  used for modal analysis of initially deflected piezo-actuated micro-plates with different designs. The approach is an alternative to more expensive laser doppler vibrometers. Finally we discuss modelling of certain piezoelectric micromachined transducers and how the modelling helps designing their electrode structure.

Biographie:

Professor Einar Halvorsen received the Siv.Ing. degree in physical electronics from the Norwegian Institute of Technology (NTH), Trondheim, Norway, in 1991, and the Dr.-Ing. degree in physics from the Norwegian University of Science and Technology (NTNU), Trondheim, in 1996. He has professional experience in both academia and the microelectronics industry. Currently, he is a Professor in the Department of Microsystems at the University of South-Eastern Norway (USN) in Horten, Norway. His research interests include solid-state physics, microelectromechanical systems (MEMS), energy harvesting, and the theoretical modeling and design of microelectromechanical devices.