US4523122A
Expired / Lapsed
US
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Piezoelectric ultrasonic transducers having acoustic impedance-matching layers
Assignee: Panasonic Holdings Corp
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Filing: 1984-03-16
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Granted: 1985-06-11
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Expires: 2004-03-16
Abstract
Abstract Ultrasonic transducers comprising an ultrasonic transducer element, a pair of electrodes provided on opposite sides of the element, and an acoustic impedance-matching layer formed on an ultrasonic wave-radiating surface of the element through one electrode. The acoustic impedance-matching layer is made of a porous polymer film or a composite material comprising thermally expanded resin microspheres dispersed in a cured product of thermosetting resin and has an acoustic impedance not larger than 0.6x106 Ns/m3. Two-layer constructions may also be used as the acoustic impedance-matching layer.
Inventors
- 👤 Masayuki Tone
- 👤 Tsutomu Yano
- 👤 Koetsu Saito
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 07:58
CPC Classifications
G; G10; G10K; G10K11/00; G10K11/02
Claims Analysis
Total Claims: 30
Claim 1
Independent Claim
83 words
An ultrasonic transducer comprising an ultrasonic transducer element, a pair of electrodes provided on opposite sides of said ultrasonic transducer element, and an acoustic impedance-matching layer formed on an ultrasonic wave-radiating surface of said ultrasonic transducer element through one electrode, said acoustic impedance-matching layer being made of a porous polymer film having a thickness of approximately a quarter wavelength or odd harmonics at the frequency generated from said transducer element and having an acoustic impedance not larger than 0.6×10 6 Ns/m 3 .
Claim 2
Dependent Claim
83 words
An ultrasonic transducer comprising an ultrasonic transducer element, a pair of electrodes provided on opposite sides of said ultrasonic transducer element, and an acoustic impedance-matching layer formed on an ultrasonic wave-radiating surface of said ultrasonic transducer element through one electrode, said acoustic impedance-matching layer being made of a porous polymer film having a thickness of approximately a quarter wavelength or odd harmonics at the frequency generated from said transducer element and having an acoustic impedance not larger than 0.6×10 6 Ns/m 3 .
Claim 3
Dependent Claim
25 words
The ultrasonic transducer according to claim 1, wherein said porous polymer film has a porosity of 50 to 90% and is made of a polyolefin.
Claim 4
Dependent Claim
21 words
The ultrasonic transducer according to claim 1, further comprising a protective film brought into intimate contact with said acoustic impedance-matching layer.
Claim 5
Dependent Claim
27 words
The ultrasonic transducer according to claim 1, further comprising a backing member bonded to a surface of said transducer element opposite to the ultrasonic wave radiation surface.
Claim 6
Dependent Claim
94 words
An ultrasonic transducer comprising an ultrasonic transducer element, a pair of electrodes provided on opposite sides of said ultrasonic transducer element, and an acoustic impedance-matching layer formed on an ultrasonic wave radiation surface of said ultrasonic transducer element through one electrode, said acoustic impedance-matching layer being made of a composite material of thermally expanded resin microballoons dispersed in a synthetic resin matrix, having a thickness of approximately a quarter wavelength or odd harmonics at the frequency generated from said transducer element and having an acoustic impedance not larger than 0.6×10 6 Ns/m 3 .
Claim 7
Dependent Claim
94 words
An ultrasonic transducer comprising an ultrasonic transducer element, a pair of electrodes provided on opposite sides of said ultrasonic transducer element, and an acoustic impedance-matching layer formed on an ultrasonic wave radiation surface of said ultrasonic transducer element through one electrode, said acoustic impedance-matching layer being made of a composite material of thermally expanded resin microballoons dispersed in a synthetic resin matrix, having a thickness of approximately a quarter wavelength or odd harmonics at the frequency generated from said transducer element and having an acoustic impedance not larger than 0.6×10 6 Ns/m 3 .
Claim 8
Dependent Claim
28 words
The ultrasonic transducer according to claim 5, wherein said composite material comprises 15 to 65% by volume of the resin microballoons and the balance of the resin matrix.
Claim 9
Dependent Claim
20 words
The ultrasonic transducer according to claim 5, wherein the resin microballoons have a size ranging from 10 to 100 microns.
Claim 10
Dependent Claim
44 words
The ultrasonic transducer according to claim 5, further comprising hollow microspheres of at least one type which have a modulus of elasticity larger than that of the thermally expanded resin microballoons in an amount of 0.02 to 0.2 wt% based on the resin microballoons.
Claim 11
Dependent Claim
17 words
The ultrasonic transducer according to claim 8, wherein said hollow microballoons are made of glass or carbon.
Claim 12
Dependent Claim
41 words
The ultrasonic transducer according to claim 5, wherein the thermally expanded resin microballoons are dispersed in the resin matrix such that the size thereof decreases towards the direction of the interface between said acoustic impedance-matching layer and the electrode contacting therewith.
Claim 13
Dependent Claim
24 words
The ultrasonic transducer according to claim 5, wherein said resin matrix is a member selected from the group consisting of epoxy and silicone resins.
Claim 14
Dependent Claim
21 words
The ultrasonic transducer according to claim 5, further comprising a protective layer brought into intimate contact with said acoustic impedance-matching layer.
Claim 15
Dependent Claim
16 words
The ultrasonic transducer according to claim 12, wherein the protective layer is a thin plastic film.
Claim 16
Dependent Claim
94 words
An ultrasonic transducer comprising an ultrasonic transducer element, a pair of electrodes provided on opposite sides of said ultrasonic transducer element, a first acoustic impedance-matching layer formed on an ultrasonic wave radiation surface of said ultrasonic transducer element through one electrode, and a second acoustic impedance-matching layer formed on the first acoustic impedance-matching layer, the first and second acoustic impedance-matching layers having acoustic impedances defined by the following equations when the acoustic impedances of the first and second layers are, respectively, X×10 6 Ns/m 3 and Y×10 6 Ns/m 3 , 1.5≦X≦7.2Y+4.9, and 0.08≦Y≦0.6
Claim 17
Dependent Claim
94 words
An ultrasonic transducer comprising an ultrasonic transducer element, a pair of electrodes provided on opposite sides of said ultrasonic transducer element, a first acoustic impedance-matching layer formed on an ultrasonic wave radiation surface of said ultrasonic transducer element through one electrode, and a second acoustic impedance-matching layer formed on the first acoustic impedance-matching layer, the first and second acoustic impedance-matching layers having acoustic impedances defined by the following equations when the acoustic impedances of the first and second layers are, respectively, X×10 6 Ns/m 3 and Y×10 6 Ns/m 3 , 1.5≦X≦7.2Y+4.9, and 0.08≦Y≦0.6
Claim 18
Dependent Claim
37 words
The ultrasonic transducer according to claim 14, wherein the second acoustic impedance-matching layer is a porous polymer film having a thickness of approximately a quarter wavelength or odd harmonics at the frequency generated from said transducer element.
Claim 19
Dependent Claim
17 words
The ultrasonic transducer according to claim 15, wherein said porous polyme film is made of a polyolefin.
Claim 20
Dependent Claim
22 words
The ultrasonic transducer according to claim 15, further comprising a protective film brought into intimate contact with the second acoustic impedance-matching layer.
Claim 21
Dependent Claim
115 words
An ultrasonic transducer comprising an ultrasonic transducer element, a pair of electrodes provided on opposite sides of said ultrasonic transducer element, a first acoustic impedance-matching layer formed on an ultrasonic wave radiation surface of said ultrasonic transducer element through one electrode, and a second acoustic impedance-matching layer formed on the first acoustic impedance-matching layer, the first and second acoustic impedance-matching layers having acoustic impedances defined by the following equations when the acoustic impedances of the first and second layers are, respectively, X×10 6 Ns/m 3 and Y×10 6 Ns/m 3 , 1.5≦X≦7.2Y+4.9, and 0.08≦Y≦0.6, the second acoustic impedance-matching layer being made of a composite material of thermally expanded microballoons dispersed in a synthetic resin matrix.
Claim 22
Dependent Claim
115 words
An ultrasonic transducer comprising an ultrasonic transducer element, a pair of electrodes provided on opposite sides of said ultrasonic transducer element, a first acoustic impedance-matching layer formed on an ultrasonic wave radiation surface of said ultrasonic transducer element through one electrode, and a second acoustic impedance-matching layer formed on the first acoustic impedance-matching layer, the first and second acoustic impedance-matching layers having acoustic impedances defined by the following equations when the acoustic impedances of the first and second layers are, respectively, X×10 6 Ns/m 3 and Y×10 6 Ns/m 3 , 1.5≦X≦7.2Y+4.9, and 0.08≦Y≦0.6, the second acoustic impedance-matching layer being made of a composite material of thermally expanded microballoons dispersed in a synthetic resin matrix.
Claim 23
Dependent Claim
32 words
The ultrasonic transducer according to claim 18, wherein said composite material further comprises at least one type of microballoons which have a modulus of elasticity larger than said thermally expanded resin microballoons.
Claim 24
Dependent Claim
38 words
The ultrasonic transducer according to claim 19, wherein said at least one type of microballoons are glass or carbon balloons and are used in an amount of 0.02 to 0.2 wt% based on said thermally expanded resin microballoons.
Claim 25
Dependent Claim
35 words
The ultrasonic transducer according to claim 18, wherein the first and second acoustic impedance-matching layers have each a thickness of approximately a quarter wavelength or odd harmonics at the frequency generated from said transducer element.
Claim 26
Dependent Claim
20 words
The ultrasonic transducer according to claim 18, wherein the first acoustic impedance-matching layer is made of a cured epoxy resin.
Claim 27
Dependent Claim
28 words
The ultrasonic transducer according to claim 18, wherein the first acoustic impedance-matching layer is made of a cured epoxy resin dispersing therein powder of tungsten or silicon carbide.
Claim 28
Dependent Claim
18 words
The ultrasonic transducer according to claim 18, the synthetic resin matrix is a cured epoxy or silicone resin.
Claim 29
Dependent Claim
22 words
The ultrasonic transducer according to claim 18, further comprising a protective film brought into intimate contact with the second acoustic impedance-matching layer.
Claim 30
Dependent Claim
16 words
The ultrasonic transducer according to claim 25, wherein said protective layer is a thin plastic film.
References Cited (Backward Citations)
US3394586A
Cited
US3678737A
Cited
US3732444A
Cited
US3674945A
Cited
US3663842A
Cited
US3883841A
Cited
US4211948A
Cited
US4366406A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1988-06-10 | 1988-12-10 | 1989-06-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-06-10 | 1992-12-10 | 1993-06-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-06-10 | 1996-12-10 | 1997-06-11 | $7700.00 | Window Closed / Lapsed |