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Multi-layer PZT microactuator having a poled but inactive PZT constraining layer

  • US 9,741,376 B1
  • Filed: 08/03/2016
  • Issued: 08/22/2017
  • Est. Priority Date: 03/18/2013
  • Status: Active Grant
First Claim
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1. A multi-layer piezoelectric microactuator assembly comprising:

  • a first piezoelectric layer and a second piezoelectric layer, each of the first and second piezoelectric layers comprising poled piezoelectric material, the first piezoelectric layer being closer to a surface to which the microactuator assembly is bonded than is the second piezoelectric layer;

    a first electrode on a bottom side of the first piezoelectric layer; and

    a second electrode on a top side of the first piezoelectric layer and disposed underneath the second piezoelectric layer, such that a first voltage differential applied across the first and second electrodes induces an electric field across the first piezoelectric layer;

    wherein;

    the first electrode is operatively connected to a first voltage and the second electrode is operatively connected to a second voltage different from the first voltage thereby defining a first voltage differential applied across the first piezoelectric layer, the first voltage differential inducing a first electric field across the first piezoelectric layer causing the first piezoelectric layer to expand or contract; and

    substantially no voltage differential is applied across the second piezoelectric layer;

    whereby;

    the second piezoelectric layer is a substantially inactive piezoelectric layer and acts as a constraining layer to resist expansion or contraction of the first piezoelectric layer; and

    an overall expansion of contraction of the microactuator assembly is made to be greater in response to the first voltage differential being applied across the first piezoelectric layer than if the second piezoelectric layer were not present.

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