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1. (WO2017153363) CONTROLLING MECHANICAL PROPERTIES OF A MEMS MICROPHONE WITH CAPACITIVE AND PIEZOELECTRIC ELECTRODES

Pub. No.:    WO/2017/153363    International Application No.:    PCT/EP2017/055241
Publication Date: Fri Sep 15 01:59:59 CEST 2017 International Filing Date: Wed Mar 08 00:59:59 CET 2017
IPC: H04R 19/00
H04R 19/04
Applicants: ROBERT BOSCH GMBH
Inventors: DOLLER, Andrew
SRIDHARAN, Sucheendran
Title: CONTROLLING MECHANICAL PROPERTIES OF A MEMS MICROPHONE WITH CAPACITIVE AND PIEZOELECTRIC ELECTRODES
Abstract:
Microphone systems including a MEMS microphone and an electronic controller. The MEMS microphone includes a movable membrane and a backplate. The movable membrane includes a capacitive electrode and a piezoelectric electrode. The capacitive electrode is configured such that acoustic pressures acting on the movable membrane cause movement of the capacitive electrode. The piezoelectric electrode alters a mechanical property of the MEMS microphone based on a control signal. The backplate is positioned on a first side of the movable membrane. The electronic controller is electrically coupled to the piezoelectric electrode and is configured to generate the control signal.