US3840824A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Acoustic surface wave device
Assignee: United States Department of the Army
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Filing: 1973-07-20
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Granted: 1974-10-08
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Expires: 1993-07-20
Abstract
Abstract A technique is disclosed for substantially improving the efficiency over a broad band of frequencies of a wedge type transducer mounted on a substrate capable of propagating elastic surface waves by interposing a thin coupling layer of appropriate material and thickness between the wedge and the substrate. The layer serves to control the effect of the wedge on the propagation characteristics of the surface wave and thereby matches the characteristics of the resulting wave to the bulk wave transducer that is employed as a component part of the wedge transducer.
Inventors
- 👤 H Bertoni
- 👤 T Tamir
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 16:38
CPC Classifications
H; H03; H03H; H03H9/00; H03H9/02; H03H9/125; H03H9/145; H03H9/14502; H03H9/02535; H03H9/02818; H03H9/02866
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
119 words
A device for coupling an electrical signal and an elastic surface wave propagating along the surface of a substrate comprising a wedge having a slant face and a second face disposed opposite said slant face, a coupling layer interposed only between said second face of said wedge and said substrate, said wedge and said layer altering the configuration of said elastic surface wave over that portion of said substrate juxtaposed with said wedge to form a leaky surface wave having fields that propagate into said wedge, and a bulk wave transducer mounted on said slant face and capable of reciprocal conversion of electrical energy and elastic energy contained in the fields of said leaky surface wave within said wedge.
Claim 2
Independent Claim
119 words
A device for coupling an electrical signal and an elastic surface wave propagating along the surface of a substrate comprising a wedge having a slant face and a second face disposed opposite said slant face, a coupling layer interposed only between said second face of said wedge and said substrate, said wedge and said layer altering the configuration of said elastic surface wave over that portion of said substrate juxtaposed with said wedge to form a leaky surface wave having fields that propagate into said wedge, and a bulk wave transducer mounted on said slant face and capable of reciprocal conversion of electrical energy and elastic energy contained in the fields of said leaky surface wave within said wedge.
Claim 3
Dependent Claim
72 words
A device as set forth in claim 1 wherein the angle theta between the slant face of said wedge and the surface of said substrate is given by theta sin 1 Beta /k where Beta is the phase constant along the substrate of the leaky surface wave in the combined medium consisting of the wedge and jUxtaposed layered substrate and k is the wave-number of the leaky wave fields in said wedge.
Claim 4
Dependent Claim
23 words
A device according to claim 1 wherein the layer material has a shear modulus small compared with the shear modulus of said substrate.
Claim 5
Dependent Claim
13 words
A device according to claim 1 wherein said layer material is an epoxy.
Claim 6
Dependent Claim
14 words
A device according to claim 1 wherein said layer material is composed of indium.
Claim 7
Dependent Claim
67 words
A device according to claim 1 wherein the velocity of propagation of the elastic shear wave within said layer is slightly greater than the velocity of propagation of the elastic shear wave in said substrate, and wherein the ratio of the mass density Rho L of said layer and the mass density Rho S of said substrate satisfies the relation Rho L/ Rho S < 1/2 .
Claim 8
Dependent Claim
49 words
A device according to claim 1 wherein the width w of the bulk wave transducer in the plane of incidence is given substantially by the relation w 1.3 cos theta / Alpha where Alpha is the attenuation constant of the bulk wave in the combined three-layer medium Beta ''.
Claim 9
Dependent Claim
23 words
A device according to claim 2 wherein the layer material has a shear modulus small compared with the shear modulus of said substrate.
Claim 10
Dependent Claim
13 words
A device according to claim 2 wherein said layer material is an epoxy.
Claim 11
Dependent Claim
14 words
A device according to claim 2 wherein said layer material is composed of indium.
Claim 12
Dependent Claim
67 words
A device according to claim 2 wherein the velocity of propagation of the elastic shear wave within said layer is slightly greater than the velocity of propagation of the elastic shear wave in said substrate, and wherein the ratio of the mass density Rho L of said layer and the mass density Rho S of said substrate satisfies the relation Rho L/ Rho S < 1/2 .
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-10-07 | 1978-04-08 | 1978-10-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-10-07 | 1982-04-08 | 1982-10-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-10-07 | 1986-04-08 | 1986-10-08 | $7700.00 | Window Closed / Lapsed |