US4012650A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Diced substrate S.A.W. device for bulk wave attenuation
Assignee: US Philips Corp
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Filing: 1974-08-29
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Granted: 1977-03-15
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Expires: 1994-08-29
Abstract
Abstract In acoustic surface wave devices the bottom of the substrate is provided with a plurality of discrete recesses to attenuate and/or scatter bulk waves.
Inventors
- 👤 Ronald George Pratt
- 👤 Richard Stevens
- 👤 Alojzy Karr
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 19:57
CPC Classifications
H; H03; H03H; H03H3/00; H03H3/007; H03H3/08; H03H9/00; H03H9/02; H03H9/02535; H03H9/02614; H03H9/02622; H03H9/02818; H03H9/02866
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
158 words
An acoustic surface-wave device comprising a body in the form of a wafer having a layer extending under a first major surface and made of a piezoelectric material, which first major surface serves as a propagation surface for the acoustic surface waves, a transducer coupled to said first major surface for converting an electric signal into a surface wave or conversely, and a plurality of discrete recesses being formed in and distributed over at least a portion of the second major surface of the wafer, which recesses extend into the wafer to a distance from the first major surface such that propagation of the acoustic surface waves is substantially unaffected whereas propagation of bulk waves is significantly affected in an attenuating and/or scattering sense, the said recesses together with the surrounding intermediate areas being arranged in a configuration such that any straight line which joins any two edges of said second surface intersects at least one intermediate area.
Claim 2
Dependent Claim
158 words
An acoustic surface-wave device comprising a body in the form of a wafer having a layer extending under a first major surface and made of a piezoelectric material, which first major surface serves as a propagation surface for the acoustic surface waves, a transducer coupled to said first major surface for converting an electric signal into a surface wave or conversely, and a plurality of discrete recesses being formed in and distributed over at least a portion of the second major surface of the wafer, which recesses extend into the wafer to a distance from the first major surface such that propagation of the acoustic surface waves is substantially unaffected whereas propagation of bulk waves is significantly affected in an attenuating and/or scattering sense, the said recesses together with the surrounding intermediate areas being arranged in a configuration such that any straight line which joins any two edges of said second surface intersects at least one intermediate area.
Claim 3
Dependent Claim
40 words
A device as claimed in claim 1 wherein the distance of the deepest point of a recess from the first major surface lies between three and five times the wavelength of the surface wave propagating along the first major surface.
Claim 4
Dependent Claim
25 words
A device as claimed in claim 1 wherein the ratio between the lengths of any two cross-sections of each recess is not greater than six.
Claim 5
Dependent Claim
22 words
A device as claimed in claim 1 wherein the side walls of the recesses extend substantially perpendicular to the first major surface.
Claim 6
Dependent Claim
49 words
A device as claimed in claim 1 wherein the recesses are formed in the second major surface in the form of a matrix pattern of rows and columns inclined at an angle other than 90° to the direction of propagation of the surface waves in the first major surface.
Claim 7
Dependent Claim
15 words
A device as claimed in claim 5 wherein said angle lies between 40° and 50°.
Claim 8
Dependent Claim
22 words
A device as claimed in claim 1 wherein the recesses in the second major surface are formed by ultrasonically drilling said surface.
Claim 9
Dependent Claim
49 words
A device as claimed in claim 2 wherein the recesses are arranged in the second major surface in the form of a matrix pattern of rows and columns inclined at an angle other than 90° to the direction of propagation of the surface waves in the first major surface.
Claim 10
Dependent Claim
25 words
A device as claimed in claim 8 wherein the side walls of the recesses extend in a direction substantially perpendicular to the first major surface.
Claim 11
Dependent Claim
136 words
An acoustic surface wave device comprising a thin body of material capable of supporting acoustic waves, an electroacoustic transducer coupled to a first major surface of said body which serves as the acoustic surface wave propagation surface of the device, and a plurality of discrete recesses formed in and distributed over a portion of a second major surface of the body which is parallel to the first major surface, said recesses extending into the body in a direction towards the first major surface for a distance such that propagation of acoustic surface waves is substantially unaffected whereas the propagation of bulk acoustic waves is substantially inhibited, said recesses being arranged in a pattern to prevent the formation of any straight grooves in said second major surface extending between any two edges of the second major surface.
Claim 12
Dependent Claim
136 words
An acoustic surface wave device comprising a thin body of material capable of supporting acoustic waves, an electroacoustic transducer coupled to a first major surface of said body which serves as the acoustic surface wave propagation surface of the device, and a plurality of discrete recesses formed in and distributed over a portion of a second major surface of the body which is parallel to the first major surface, said recesses extending into the body in a direction towards the first major surface for a distance such that propagation of acoustic surface waves is substantially unaffected whereas the propagation of bulk acoustic waves is substantially inhibited, said recesses being arranged in a pattern to prevent the formation of any straight grooves in said second major surface extending between any two edges of the second major surface.
Claim 13
Dependent Claim
34 words
A device as claimed in claim 10 wherein said body is formed of at least two adjacent layers of dissimilar materials with one layer forming said first major surface and comprising a piezoelectric material.
Claim 14
Dependent Claim
54 words
A device as claimed in claim 10 wherein the recesses extend into the body in a direction perpendicular to the first major surface to a point spaced from the first major surface that lies between three and five times the wavelength of the acoustic surface wave to be propagated along said first major surface.
Claim 15
Dependent Claim
39 words
A device as claimed in claim 10 wherein the recesses are arranged in a matrix pattern of rows and columns inclined at an acute angle to the propagation direction of the acoustic surface waves in the first major surface.
References Cited (Backward Citations)
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-03-14 | 1980-09-13 | 1981-03-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-03-14 | 1984-09-13 | 1985-03-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-03-14 | 1988-09-13 | 1989-03-15 | $7700.00 | Window Closed / Lapsed |