Piezoelectric sensor based on electrets thermoforming technology: improvements on the production processes

Author(s)

Daniel Rodrigo Falconi

• Document type: Master's Dissertation
• Press: São Carlos.
• Institution: Universidade de São Paulo (USP). Escola de Engenharia de São Carlos (EESC/SBD)
• Defense date: 2010-02-12

Examining board members

Ruy Alberto Corrêa Altafim; Heitor Cury Basso; João Sinézio de Carvalho Campos

• Advisor: Ruy Alberto Corrêa Altafim

Abstract

This work describes two improvements on the production of piezoelectric sensors, which are based on thermo-formed electrets technology. These sensors which were previously prepared by fusing and molding two Teflon FEP films into bubbles structures in a hot-press system, presented piezoelectric coefficients over 300 pC/N after properly electrical charging. However, this production system still presents many technical challenges, most of them concerning the bubble formation. With the improvements, called hot lamination and cold adhesive, a much better control of the distribution, height and diameter of the air bubbles could be obtained. These improvements process can be described into four main stages: the molding of one film; the sticking process of the two films; the metallization of their surfaces followed by electric charging. The sticking processes and the previous molding of the film are crucial and the great contribution of this work. With these contributions not only better sensor could be made but it also facilitated the industrial scale implementation of the sensors. Another expressive contribution of this work was the development of a system to measure the piezoelectric coefficient. (AU)

• FAPESP's process: 06/05528-0 - Piezoelectric sensor based on electret thermoforming technology: a new industrial process
• Grantee: Daniel Rodrigo Falconi
• Support Opportunities: Scholarships in Brazil - Master