US3887887A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Acoustic bulk mode suppressor
Assignee: Texas Instruments Inc
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Filing: 1973-12-28
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Granted: 1975-06-03
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Expires: 1993-12-28
Abstract
Abstract An acoustic surface wave device and a method of constructing such a device which has much lower spurious responses resulting in improved operation. In a specific embodiment, the back surface of the surface wave device is treated by sand blasting or the like to form a plurality of depressions therein which act to randomly scatter undesired modes in the substrate thereby materially improving the device response.
Inventors
- 👤 Rogert S Wagers
- 👤 Michael J Birch
- 👤 Clinton S Hartmann
- 👤 Donald F Weirauch
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 21:39
CPC Classifications
H; H03; H03H; H03H9/00; H03H9/30; H03H3/00; H03H3/007; H03H3/08; H03H9/02; H03H9/02535; H03H9/02614; H03H9/02622; H03H9/02818; H03H9/02866; Y; Y10; Y10T; Y10T29/00; Y10T29/42; Y10T29/49; Y10T29/49002; Y10T29/49005
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
184 words
An acoustic surface wave device comprising: a substrate of piezoelectric material having a parallelepiped configuration, said substrate having a pair of major surface areas in spaced parallel relationship with respect to each other and defining top and bottom surfaces respectively thereof, at least one acoustic surface wave transducer disposed on said top surface of said substrate for generating acoustic surface waves propagatIng along said top surface of said substrate, and means defining a multiplicity of topographic deformations on the bottom surface of said substrate, said multiplicity of topographic deformations being spaced apart in a random pattern and having respective width dimensions on the order of magnitude of one-half acoustic wavelength of the acoustic surface waves to be generated by said at least one acoustic surface wave transducer disposed on the top surface of said substrate, and the spacing between adjacent ones of said topographic deformations being of the order of magnitude of the acoustic wavelength along the direction of propagation of acoustic surface waves to be generated by said at least one acoustic surface wave transducer disposed on the top surface of said substrate.
Claim 2
Dependent Claim
184 words
An acoustic surface wave device comprising: a substrate of piezoelectric material having a parallelepiped configuration, said substrate having a pair of major surface areas in spaced parallel relationship with respect to each other and defining top and bottom surfaces respectively thereof, at least one acoustic surface wave transducer disposed on said top surface of said substrate for generating acoustic surface waves propagatIng along said top surface of said substrate, and means defining a multiplicity of topographic deformations on the bottom surface of said substrate, said multiplicity of topographic deformations being spaced apart in a random pattern and having respective width dimensions on the order of magnitude of one-half acoustic wavelength of the acoustic surface waves to be generated by said at least one acoustic surface wave transducer disposed on the top surface of said substrate, and the spacing between adjacent ones of said topographic deformations being of the order of magnitude of the acoustic wavelength along the direction of propagation of acoustic surface waves to be generated by said at least one acoustic surface wave transducer disposed on the top surface of said substrate.
Claim 3
Dependent Claim
184 words
An acoustic surface wave device comprising: a substrate of piezoelectric material having a parallelepiped configuration, said substrate having a pair of major surface areas in spaced parallel relationship with respect to each other and defining top and bottom surfaces respectively thereof, at least one acoustic surface wave transducer disposed on said top surface of said substrate for generating acoustic surface waves propagatIng along said top surface of said substrate, and means defining a multiplicity of topographic deformations on the bottom surface of said substrate, said multiplicity of topographic deformations being spaced apart in a random pattern and having respective width dimensions on the order of magnitude of one-half acoustic wavelength of the acoustic surface waves to be generated by said at least one acoustic surface wave transducer disposed on the top surface of said substrate, and the spacing between adjacent ones of said topographic deformations being of the order of magnitude of the acoustic wavelength along the direction of propagation of acoustic surface waves to be generated by said at least one acoustic surface wave transducer disposed on the top surface of said substrate.
Claim 4
Dependent Claim
184 words
An acoustic surface wave device comprising: a substrate of piezoelectric material having a parallelepiped configuration, said substrate having a pair of major surface areas in spaced parallel relationship with respect to each other and defining top and bottom surfaces respectively thereof, at least one acoustic surface wave transducer disposed on said top surface of said substrate for generating acoustic surface waves propagatIng along said top surface of said substrate, and means defining a multiplicity of topographic deformations on the bottom surface of said substrate, said multiplicity of topographic deformations being spaced apart in a random pattern and having respective width dimensions on the order of magnitude of one-half acoustic wavelength of the acoustic surface waves to be generated by said at least one acoustic surface wave transducer disposed on the top surface of said substrate, and the spacing between adjacent ones of said topographic deformations being of the order of magnitude of the acoustic wavelength along the direction of propagation of acoustic surface waves to be generated by said at least one acoustic surface wave transducer disposed on the top surface of said substrate.
Claim 5
Independent Claim
125 words
A method of treating the substrate of an acoustic surface wave device to improve its signal to spurious mode ratio, wherein the substrate is of piezoelectric material and has a parallelepiped configuration providing major surface areas in spaced parallel relationship with respect to each other and defining top and bottom surfaces respectively thereof, said method comprising: disposing a mask having a plurality of openings therethough in registration with the bottom surface of the substrate, directing abrasive particles toward the mask from the side thereof opposite from the substrate, and forming a multiplicity of spaced topographic deformations on the bottom surface of the substrate by the impingement on the bottom surface of the substrate of abrasive particles passing through the plurality of openings in the mask.
Claim 6
Independent Claim
125 words
A method of treating the substrate of an acoustic surface wave device to improve its signal to spurious mode ratio, wherein the substrate is of piezoelectric material and has a parallelepiped configuration providing major surface areas in spaced parallel relationship with respect to each other and defining top and bottom surfaces respectively thereof, said method comprising: disposing a mask having a plurality of openings therethough in registration with the bottom surface of the substrate, directing abrasive particles toward the mask from the side thereof opposite from the substrate, and forming a multiplicity of spaced topographic deformations on the bottom surface of the substrate by the impingement on the bottom surface of the substrate of abrasive particles passing through the plurality of openings in the mask.
Claim 7
Independent Claim
161 words
A method of treating the substrate of an acoustic surface wave device to improve its signal to spurious mode ratio, wherein the substrate is of piezoelectric material and has a parallelepiped configuration providing major surface areas in spaced parallel relationship with respect to each other and defining top and bottom surfaces respectively thereof, said method comprising: placing a stencil with an aperture pattern having a grid spacing of the order of magnitude of an acoustic wavelength relative to the acoustic surface waves to be propagated along the top surface of the substrate in spaced relation between the bottom surface of the substrate and a sand blasting apparatus, operating the sand blasting apparatus to strike the bottom surface of the substrate with abrasive particles in spaced positions thereon as determined by the grid spacing of the stencil, and forming a multiplicity of spaced topographic deformations on the bottom surface of the substrate in response to the impingement of the abrasive particles thereon.
Claim 8
Independent Claim
161 words
A method of treating the substrate of an acoustic surface wave device to improve its signal to spurious mode ratio, wherein the substrate is of piezoelectric material and has a parallelepiped configuration providing major surface areas in spaced parallel relationship with respect to each other and defining top and bottom surfaces respectively thereof, said method comprising: placing a stencil with an aperture pattern having a grid spacing of the order of magnitude of an acoustic wavelength relative to the acoustic surface waves to be propagated along the top surface of the substrate in spaced relation between the bottom surface of the substrate and a sand blasting apparatus, operating the sand blasting apparatus to strike the bottom surface of the substrate with abrasive particles in spaced positions thereon as determined by the grid spacing of the stencil, and forming a multiplicity of spaced topographic deformations on the bottom surface of the substrate in response to the impingement of the abrasive particles thereon.
References Cited (Backward Citations)
US3564461A
Cited
US3781721A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-06-02 | 1978-12-02 | 1979-06-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-06-02 | 1982-12-02 | 1983-06-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-06-02 | 1986-12-02 | 1987-06-03 | $7700.00 | Window Closed / Lapsed |