Hybrid capacitive and piezoelectric motion sensing transducer

摘要

A motion sensing transducer includes an electrically conductive substrate having a major surface that defines a substrate plane, and a first compliant structure including a piezoelectric material and having greater compliance to inertial forces oriented out of the substrate plane than to inertial forces oriented in the substrate plane. The first compliant structure includes a piezoelectric material. The motion sensing transducer includes a second compliant structure having greater compliance to inertial forces oriented in the substrate plane than to inertial forces oriented out of the substrate plane. The second compliant structure includes a first surface that is electrically isolated from the substrate. The first surface faces a surface of the substrate. The motion sensing transducer includes a first electrically conductive lead that is electrically connected to the first surface, and a second electrically conductive lead that is electrically connected to the piezoelectric material.

主权项

1. A hybrid capacitive and piezoelectric motion sensing transducer comprising:
a bottom substrate layer; an upper substrate layer being electrically conductive and having a major surface that defines a substrate plane; a buried oxide layer disposed between the bottom substrate layer and the upper substrate layer; a piezoelectric layer; a top oxide layer disposed between the upper substrate layer and the piezoelectric layer; a first piezoelectric accelerometer comprising a first compliant structure patterned in the piezoelectric layer and having greater compliance to inertial forces oriented out of the substrate plane than to inertial forces oriented in the substrate plane; a first capacitive accelerometer comprising a second compliant structure patterned in the upper substrate layer and having greater compliance to inertial forces oriented in the substrate plane than to inertial forces oriented out of the substrate plane, the second compliant structure including a first surface that faces a second surface of the upper substrate layer and that is separated from the second surface by a spacing that varies with an in-plane displacement of the second compliant structure; and a first electrically conductive lead that is electrically connected to the first surface, and a second electrically conductive lead that is electrically connected to the piezoelectric material, wherein a capacitance between the first electrically conductive lead and the second surface varies with the in-plane displacement of the second compliant structure.