Acoustic wave etch rate sensor system
First Claim
1. An acoustic wave sensor system for monitoring the etchability of a material exposed to an etchant, the sensor system comprising:
- an acoustic wave sensing device havinga piezoelectric substrate, anda pair of electrodes, coupled to said substrate, said pair of electrodes being adapted and arranged to generate an acoustic wave propagating in the device upon application of a voltage potential and to transform the propagating wave into an output response,a selective material disposed on said substrate, said material being chemically reactive with said etchant such that said material is etchable by said etchant,wherein one of said electrodes is at least partially formed from said selective material or has said selective material disposed thereon, andwherein the other of said electrodes is made inactive to said etchant; and
at least one reflector for reflecting the propagating wave back to at least one electrode;
whereby, said sensing device can provide an output response in which changes in frequency, phase or other propagation characteristics of said wave caused by etching of said selective material can be analyzed to evaluate the etching rate or etchability of said selective material.
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Abstract
An acoustic wave sensor system for monitoring the etch rate or etch ability of a selective material has an acoustic wave sensing device having a piezoelectric substrate and at least one electrode coupled to the substrate for generating a propagating acoustic wave and for detecting changes in frequency or other propagation characteristics of the acoustic wave. A selective material is disposed on the substrate. Changes in propagation characteristics of the wave caused by etching of the selective material by an etchant can be analyzed to evaluate the etching rate or etch ability of the selective material. The sensing system can have a wireless sensing device which device is mountable in an oil filter system for monitoring the corrosion of the engine. The sensing device can be configured as BAW, SH-SAW, SH-APM, FPM devices or other acoustic wave devices.
38 Citations
18 Claims
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1. An acoustic wave sensor system for monitoring the etchability of a material exposed to an etchant, the sensor system comprising:
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an acoustic wave sensing device having a piezoelectric substrate, and a pair of electrodes, coupled to said substrate, said pair of electrodes being adapted and arranged to generate an acoustic wave propagating in the device upon application of a voltage potential and to transform the propagating wave into an output response, a selective material disposed on said substrate, said material being chemically reactive with said etchant such that said material is etchable by said etchant, wherein one of said electrodes is at least partially formed from said selective material or has said selective material disposed thereon, and wherein the other of said electrodes is made inactive to said etchant; and
at least one reflector for reflecting the propagating wave back to at least one electrode;whereby, said sensing device can provide an output response in which changes in frequency, phase or other propagation characteristics of said wave caused by etching of said selective material can be analyzed to evaluate the etching rate or etchability of said selective material. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. An acoustic wave sensor system for monitoring engine corrosion, the sensor system comprising:
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an acoustic wave sensing device having a piezoelectric substrate, a pair of electrodes coupled to said substrate between a pair of reflectors, said pair of electrodes being adapted and arranged to generate an acoustic wave propagating in the device upon application of a voltage potential and to transform the propagating wave into an output response, and a selective layer of material disposed on said substrate and having a chemical reactivity such that the selective layer is etchable by degraded engine oil, wherein one of said electrodes/reflectors is at least partially formed from said selective material or has said selective material disposed thereon, said selective layer comprising a metal element or a metal alloy containing said metal element, the chemical reactivity of the layer with said oil being such that reaction products produced at an etched surface of the layer are removed by said etchant; wherein the other of said electrodes/reflectors is made inactive to said etchant, and whereby, said sensing device can provide an output response in which changes in frequency, phase or other propagation characteristics of said wave caused by etching of said selective layer can be analyzed to evaluate the etching rate of the selective layer and thereby monitor the degree of engine corrosion caused by said degraded oil. - View Dependent Claims (11, 12, 13, 14, 15)
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16. A method of sensing the etch rate of a selective material comprising:
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generating an acoustic wave propagating said acoustic wave in a piezoelectric substrate having a pair of electrodes and at least one reflector disposed thereon, reflecting the propagating wave back to at least one electrode; making one of said electrodes inactive to an etchant, forming said other electrode from a selective material or disposing said selective material thereon; etching said selective material transforming said propagating wave into an output response, and analyzing said output response to measure changes in the frequency, phase or other propagation characteristics of said wave caused by said etching. - View Dependent Claims (17, 18)
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Specification