US4326418A
Expired / Lapsed
US
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Acoustic impedance matching device
Assignee: Philips North America LLC
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Filing: 1980-04-07
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Granted: 1982-04-27
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Expires: 2000-04-07
Abstract
Abstract A impedance matching window for an ultrasound transducer comprises a periodic array of stepped structures. Each stepped structure comprises a plurality of parallel matching strips disposed side-by-side on an active surface of a piezoelectric ceramic.
Inventors
- 👤 James W. Pell, Jr.
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 10:38
CPC Classifications
G; G10; G10K; G10K11/00; G10K11/02
Claims Analysis
Total Claims: 47
Claim 1
Independent Claim
73 words
An impedance matching device for coupling wideband sonic energy between one or more acoustic transducers and an object, comprising: a periodic array of stepped matching structures disposed side-by-side over an active surface of the transducers, each of the matching structures comprising two or more flat parallel strips of sound-conductive material which are disposed, side-by-side, over the active surface in a stepped configuration wherein the thickness of successive strips increases monotonically across the structure.
Claim 2
Dependent Claim
73 words
An impedance matching device for coupling wideband sonic energy between one or more acoustic transducers and an object, comprising: a periodic array of stepped matching structures disposed side-by-side over an active surface of the transducers, each of the matching structures comprising two or more flat parallel strips of sound-conductive material which are disposed, side-by-side, over the active surface in a stepped configuration wherein the thickness of successive strips increases monotonically across the structure.
Claim 3
Dependent Claim
29 words
The device of claim 1 wherein the thickness of each of the parallel strips is one quarter wavelength at a frequency within the bandwidth of the coupled sound energy.
Claim 4
Dependent Claim
19 words
The device of claim 1 or 2 wherein the frequency response of the impedance matching device is approximately Gaussian.
Claim 5
Dependent Claim
40 words
The device of claim 1 or 2 wherein the transducers have a first acoustic impedance, the object has a second acoustic impedance, and the sound-conductive material has an acoustic impedance intermediate the first acoustic impedance and the second acoustic impedance.
Claim 6
Dependent Claim
26 words
The device of claim 4 wherein the sound conductive material has an impedance which is the geometric mean of the first impedance and the second impedance.
Claim 7
Dependent Claim
29 words
The device of claim 4 wherein the acoustic transducers comprise a piezoelectric ceramic, the object comprises animal tissue, and the sound conductive material comprises a metal filled plastic resin.
Claim 8
Dependent Claim
18 words
The device of claim 6 wherein the sound conductive material comprises tungsten powder in an epoxy resin binder.
Claim 9
Dependent Claim
16 words
The device of claim 1 wherein the transducer comprises a linear array of parallel transducer elements.
Claim 10
Dependent Claim
16 words
The device of claim 8 wherein the transducer comprises a flat linear array of transducer elements.
Claim 11
Dependent Claim
21 words
The device of claim 8 or 9 wherein the strips of the matching structures are disposed parallel to the transducer elements.
Claim 12
Dependent Claim
20 words
The device of claim 1 or 2 wherein the widths of the surfaces of adjacent parallel strips are not equal.
Claim 13
Dependent Claim
35 words
The device of claim 1 or 2 wherein each stepped matching structure comprises at least three parallel strips and wherein the incremental increase in thickness of adjacent strips varies across the width of the structure.
Claim 14
Dependent Claim
19 words
The device of claim 1 or 2 further comprising an acoustic disposed over a surface of the periodic array.
Claim 15
Dependent Claim
13 words
The device of claim 13 wherein the acoustic lens is a cylindrical lens.
Claim 16
Dependent Claim
50 words
The device of claim 1, 2 or 8 wherein the transducer comprises a flat sheet of piezoelectric material, one surface of the sheet defining a front active surface and further comprising a lossy backing layer disposed over a rear surface of the sheet which is opposite the front active surface.
Claim 17
Dependent Claim
46 words
The device of claim 10 wherein the transducer comprises a flat sheet of piezoelectrical material, one surface of the sheet defining a front active surface and further comprising a lossy backing layer disposed over a rear surface of the sheet which is opposite the active surface.
Claim 18
Dependent Claim
46 words
The device of claim 12 wherein the transducer comprises a flat sheet of transducer material, one surface of the sheet defining a front active surface and further comprising a lossy backing layer disposed over a rear surface of the sheet which is opposite the active surface.
Claim 19
Dependent Claim
108 words
A wide bandwidth acoustic transducer assembly comprising: a linear array of acoustic transducer elements formed in a sheet of piezoelectric material, the sheet having a front active surface and a rear surface which is opposite the front surface; a lossy backing layer disposed adjacent the rear surface of the sheet; matching means includes an array of stepped matching structures disposed side-by-side over the active surface of the sheet, each of the stepped structures comprising two or more flat parallel strips of sound conductive material disposed side-by-side on the active surface in a stepped configuration wherein the thickness of successive strips increases monotonically along the width of the structure.
Claim 20
Dependent Claim
108 words
A wide bandwidth acoustic transducer assembly comprising: a linear array of acoustic transducer elements formed in a sheet of piezoelectric material, the sheet having a front active surface and a rear surface which is opposite the front surface; a lossy backing layer disposed adjacent the rear surface of the sheet; matching means includes an array of stepped matching structures disposed side-by-side over the active surface of the sheet, each of the stepped structures comprising two or more flat parallel strips of sound conductive material disposed side-by-side on the active surface in a stepped configuration wherein the thickness of successive strips increases monotonically along the width of the structure.
Claim 21
Dependent Claim
26 words
The assembly of claim 18 wherein the rear surface of the sheet is grooved with a series of parallel kerfs to separate the individual transducer elements.
Claim 22
Dependent Claim
19 words
The assembly of claim 18 wherein the parallel strips of sound conductive material are disposed parallel to the kerfs.
Claim 23
Dependent Claim
18 words
The assembly of claim 19 wherein at least two stepped matching structures are disposed over each transducer element.
Claim 24
Dependent Claim
21 words
The assembly of claim 18, 19, 20, or 21 further comprising electrode means for coupling electrical energy to the transducer elements.
Claim 25
Dependent Claim
48 words
The assembly of claim 22 wherein the electrode means comprise a first electrode disposed between the active surface of the sheet and the matching means and a plurality of second electrodes, each second electrode being disposed between the rear surface of a transducer element and the backing layer.
Claim 26
Dependent Claim
34 words
The assembly of any claims 18, 19, or 20 wherein the matching structures comprise a material having an acoustic impedance intermediate the acoustic impedance of the sheet and the acoustic impedance of human tissue.
Claim 27
Dependent Claim
30 words
The assembly of claim 22 wherein the matching structures comprise a material having an acoustic impedance intermediate the acoustic impedance of the sheet and the acoustic impedance of human tissue.
Claim 28
Dependent Claim
30 words
The assembly of claim 23 wherein the matching structures comprise a material having an acoustic impedance intermediate the acoustic impedance of the sheet and the acoustic impedance of human tissue.
Claim 29
Dependent Claim
20 words
The assembly of any of claims 18 through 21 wherein the matching structure comprises metal powder and a resin binder.
Claim 30
Dependent Claim
16 words
The assembly of claim 22 wherein the matching structure comprises metal powder and a resin binder.
Claim 31
Dependent Claim
17 words
The assembly of claim 28 wherein the matching structure comprises tungsten powder in an epoxy resin binder.
Claim 32
Dependent Claim
19 words
The assembly of claim 22 further comprising an acoustic lens disposed over the matching structure and opposite the sheet.
Claim 33
Dependent Claim
12 words
The assembly of claim 30 wherein the acoustic lens comprises silicone rubber.
Claim 34
Dependent Claim
13 words
The assembly of claim 18 wherein the piezoelectric material is a PZT-5 ceramic.
Claim 35
Dependent Claim
16 words
The assembly of claim 22 wherein the backing layer comprises glass micro-balloons in a resin binder.
Claim 36
Dependent Claim
16 words
The assembly of claim 29 wherein the backing layer comprises glass micro-balloons in a resin binder.
Claim 37
Dependent Claim
33 words
The assembly of claim 18 wherein the thickness of each of the parallel strips is a quarter wavelength at a frequency within the bandwidth of energy produced or received by the transducer assembly.
Claim 38
Dependent Claim
17 words
The assembly of claim 18 wherein the widths of adjacent strips are not equal to each other.
Claim 39
Dependent Claim
11 words
The assembly of claim 18 wherein each structure comprises three strips.
Claim 40
Dependent Claim
20 words
The assembly of claim 37 wherein the widths of adjacent strips in the structure are in the ratio of 0.228:0.127:0.152.
Claim 41
Dependent Claim
21 words
The assembly of claim 28 wherein the thickness of adjacent strips in the structure are in the approximate ratio of 0.102:0.063:0.025.
Claim 42
Dependent Claim
18 words
The assembly of claim 39 wherein approximately two and one-half matching structure are disposed over each transducer element.
Claim 43
Dependent Claim
16 words
The assembly of claim 18 wherein the array of stepped matching structures is a periodic array.
Claim 44
Dependent Claim
67 words
An impedance matching device for coupling wideband sonic energy between an active surface of a first material and a second material, comprising two or more flat parallel strips of sound conductive material disposed side-by-side over the active surface, the thickness of each of the strips being one quarter wavelength some frequency component of the sonic energy and the thickness of adjacent strips being different from each other.
Claim 45
Dependent Claim
67 words
An impedance matching device for coupling wideband sonic energy between an active surface of a first material and a second material, comprising two or more flat parallel strips of sound conductive material disposed side-by-side over the active surface, the thickness of each of the strips being one quarter wavelength some frequency component of the sonic energy and the thickness of adjacent strips being different from each other.
Claim 46
Dependent Claim
13 words
The device of claim 42 wherein the first material forms an ultrasound transducer.
Claim 47
Dependent Claim
31 words
The device of claim 42 or 43 wherein the acoustic impedance of the strips is intermediate the acoustic impedance of the first material and the acoustic impedance of the second material.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1985-04-26 | 1985-10-26 | 1986-04-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-04-26 | 1989-10-26 | 1990-04-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-04-26 | 1993-10-26 | 1994-04-27 | $7700.00 | Window Closed / Lapsed |