Variable acoustic wave energy transfer-characteristic control device
First Claim
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1. A variable acoustic wave energy transfer characteristic control device including:
- a piezoelectric unit comprising a plurality of contiguous layers of piezoelectric material which define two outer faces and define an interface between each pair of adjacent ones of said contiguous layers, each of said layers having a respective specified thickness, first and second electrodes respectively at said outer faces, and at least one additional electrode at each interface;
an electrical circuit connected across said first and second electrodes; and
switch means for selectively connecting said at least one additional electrode to another one of said electrodes which selectively short circuits at least a portion of at least one of said layers of said piezoelectric element.
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Abstract
The effective thickness of a piezoelectric unit comprising a plurality of contiguous layers is varied by selectively short circuiting one or more layers with switch means. This varies the electro-acoustic properties at an operating frequency that is exhibited between the respective acoustic ports of the unit and an electrical circuit coupled across the electric port of the unit. Specific embodiments of such a unit, switch means and electrical circuit are useful in a control device for acoustic-wave propagating systems.
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Citations
12 Claims
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1. A variable acoustic wave energy transfer characteristic control device including:
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a piezoelectric unit comprising a plurality of contiguous layers of piezoelectric material which define two outer faces and define an interface between each pair of adjacent ones of said contiguous layers, each of said layers having a respective specified thickness, first and second electrodes respectively at said outer faces, and at least one additional electrode at each interface; an electrical circuit connected across said first and second electrodes; and switch means for selectively connecting said at least one additional electrode to another one of said electrodes which selectively short circuits at least a portion of at least one of said layers of said piezoelectric element. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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Specification