Multi-layer PZT microactuator having a poled but inactive PZT constraining layer
First Claim
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1. A multi-layer piezoelectric microactuator comprising:
- a plurality of piezoelectric layers configured to form the multi-layer piezoelectric microactuator, each of the plurality of piezoelectric layers including poled piezoelectric material;
a plurality of electrodes including at least a first electrode on a first side of a first piezoelectric layer of the plurality of piezoelectric layers, at least a second piezoelectric layer is a substantially inactive piezoelectric layer and is configured to act as a constraining layer to resist expansion or contraction of the first piezoelectric layer and to extend the effective stroke length of the multi-layer piezoelectric microactuator, and a second electrode on a second side of the first piezoelectric layer such that the second electrode is between the first piezoelectric layer and the second piezoelectric layer, the second electrode and the first electrode configured to induce an electric field across the first piezoelectric layer upon application of one or more voltages to one or more of the first piezoelectric layer and the second piezoelectric layer to cause the first piezoelectric layer to expand or contract.
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Abstract
A multi-layer piezoelectric microactuator assembly has at least one poled and active piezoelectric layer and one poled but inactive piezoelectric layer. The poled but inactive layer acts as a constraining layer in resisting expansion or contract of the first piezoelectric layer thereby reducing or eliminating bending of the assembly as installed in an environment, thereby increasing the effective stroke length of the assembly. Poling only a single layer would induce stresses into the device; hence, polling both piezoelectric layers even though only one layer will be active in use reduces stresses in the device and therefore increases reliability.
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Citations
21 Claims
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1. A multi-layer piezoelectric microactuator comprising:
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a plurality of piezoelectric layers configured to form the multi-layer piezoelectric microactuator, each of the plurality of piezoelectric layers including poled piezoelectric material; a plurality of electrodes including at least a first electrode on a first side of a first piezoelectric layer of the plurality of piezoelectric layers, at least a second piezoelectric layer is a substantially inactive piezoelectric layer and is configured to act as a constraining layer to resist expansion or contraction of the first piezoelectric layer and to extend the effective stroke length of the multi-layer piezoelectric microactuator, and a second electrode on a second side of the first piezoelectric layer such that the second electrode is between the first piezoelectric layer and the second piezoelectric layer, the second electrode and the first electrode configured to induce an electric field across the first piezoelectric layer upon application of one or more voltages to one or more of the first piezoelectric layer and the second piezoelectric layer to cause the first piezoelectric layer to expand or contract. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. A multi-layer piezoelectric microactuator comprising:
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a plurality of electrodes including at least a first electrode, a second electrode, and a third electrode, the first electrode and second electrode are each configured to connect to one of a driving voltage and a ground, the third electrode configured to be electrically isolated from the driving voltage and the ground; a plurality of poled piezoelectric layers configured to form the multi-layer piezoelectric microactuator, the plurality of poled piezoelectric layers include at least a first poled piezoelectric layer and a second poled piezoelectric layer, the first poled piezoelectric layer arranged between the first electrode and the second electrode, the second poled piezoelectric layer arranged between the second electrode and the third electrode and configured to extend the effective stroke length of the multi-layer piezoelectric microactuator. - View Dependent Claims (16, 17, 18, 19, 20, 21)
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Specification