US4434384A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Ultrasonic transducer and its method of manufacture
Assignee: Raytheon Co
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Filing: 1980-12-08
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Granted: 1984-02-28
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Expires: 2000-12-08
Abstract
Abstract An ultrasonic transducer and its method of fabrication wherein bonding between an impedance matching layer on one side of a piezoelectric layer and a support layer on the other side of the piezoelectric material is made by providing onto each material a smooth, thin gold film on the smooth surfaces of the layers which are to be in contact with one another in the assembled transducer. The layers are bonded to each other by the gold films under moderate temperature and pressure to form the transducer. Sawing of the impedance matching and piezoelectric layers into a plurality of parallel transducers attached to the support layer forms an array.
Inventors
- 👤 Clarence J. Dunnrowicz
- 👤 Joseph Callerame
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 00:24
CPC Classifications
B; B06; B06B; B06B1/00; B06B1/02; B06B1/06; B06B1/0607; B06B1/0622
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
116 words
A transducer comprising: an impedance matching layer; a piezoelectric layer; each layer having a surface with smooth and clean first composite gold film attached thereto; said layers being in surface contact with each other and being gold bonded to each other at their interface by said gold films; the gold film of each of said layers being sufficiently smooth and clean to produce said gold to gold bond after the application of low pressure on said layers forcing the gold films in contact with one another; a support layer of acoustically absorptive material whose impedance matches that of said piezoelectric layer, said support layer having a surface bonded to the other surface of said piezoelectric layer.
Claim 2
Dependent Claim
116 words
A transducer comprising: an impedance matching layer; a piezoelectric layer; each layer having a surface with smooth and clean first composite gold film attached thereto; said layers being in surface contact with each other and being gold bonded to each other at their interface by said gold films; the gold film of each of said layers being sufficiently smooth and clean to produce said gold to gold bond after the application of low pressure on said layers forcing the gold films in contact with one another; a support layer of acoustically absorptive material whose impedance matches that of said piezoelectric layer, said support layer having a surface bonded to the other surface of said piezoelectric layer.
Claim 3
Dependent Claim
56 words
The transducer of claim 1 wherein: said support layer and said other surface of said piezoelectric layer each having a second smooth and clean composite gold film attached thereto; said support layer gold film and said piezoelectric second gold film layer being low pressure bonded to each other at the interface of said second gold films.
Claim 4
Dependent Claim
39 words
The transducer of claim 2 wherein: said transducer layer and said matching layer bonded to each other by said gold to gold bond comprise a plurality of transversely spaced bonded layers to form an array of said bonded layers.
Claim 5
Dependent Claim
30 words
The transducer of claim 2 wherein: said impedance matching layer, said piezoelectric layer, and said support layer have a smooth surface prior to having said composite gold layer attached thereto.
Claim 6
Dependent Claim
39 words
The transducer of claim 1 wherein: said piezoelectric layer and said matching layer bonded to each other by said gold to gold bond comprise a plurality of transversely spaced bonded layers to form an array of said bonded layers.
Claim 7
Dependent Claim
55 words
The transducer of claim 1 further comprising: each of said first composite gold films comprises a first film of a material selected from the group consisting of chromium, molybdenum, and titanium deposited on and bonded to the surface of said layers; and a first gold film deposited on and forming an alloy with said material.
Claim 8
Dependent Claim
28 words
The transducer of claim 6 further comprising: said bond of said first gold film and said film of material being an alloy of said gold at said material.
Claim 9
Dependent Claim
43 words
The transducer of claim 6 further comprising: said impedance matching layer and said piezoelectric layer each having a smooth polished surface; and said composite gold film having a thickness sufficient to provide good adhesion to said polished surface of each of said layers.
Claim 10
Dependent Claim
20 words
The transducer of claim 8 wherein the thickness of said composite gold film is not greater than substantially 3000 Å.
Claim 11
Dependent Claim
32 words
The transducer of claim 6 wherein: said first film of material is chromium having a thickness of substantially 3000 Å; and said first gold film has a thickness of substantially 2000 Å.
Claim 12
Dependent Claim
25 words
The transducer of claim 1 wherein said clean composite gold film comprises a gold film whose surface is substantially free of hydrocarbons and gold oxide.
Claim 13
Dependent Claim
37 words
The transducer of claim 1 wherein said clean composite gold film comprises a film whose surface is sufficiently free of hydrocarbons and gold oxide to form said gold to gold bond under low pressure and room temperature.
Claim 14
Dependent Claim
128 words
A transducer of the type having a piezoelectric material bonded on one surface to an impedance matching material and on the other surface to an acoustically absorbing material which is impedance matched to said piezoelectric material, the improvement comprising: each of said bonded surfaces of said materials being gold bonded and prior to being so bonded having attached to each such surface a film of a metal and a film of gold in that order; said gold film being smooth, flat and free from impurities, the degree of smoothness, flatness, and freedom from impurities being such that said gold bonds are of sufficient strength to maintain said bonds after bonding by initial application of a small bonding pressure to the opposed surfaces of said matching and absorbing materials.
Claim 15
Dependent Claim
128 words
A transducer of the type having a piezoelectric material bonded on one surface to an impedance matching material and on the other surface to an acoustically absorbing material which is impedance matched to said piezoelectric material, the improvement comprising: each of said bonded surfaces of said materials being gold bonded and prior to being so bonded having attached to each such surface a film of a metal and a film of gold in that order; said gold film being smooth, flat and free from impurities, the degree of smoothness, flatness, and freedom from impurities being such that said gold bonds are of sufficient strength to maintain said bonds after bonding by initial application of a small bonding pressure to the opposed surfaces of said matching and absorbing materials.
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) | 1987-02-27 | 1987-08-29 | 1988-02-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-02-27 | 1991-08-29 | 1992-02-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-02-27 | 1995-08-29 | 1996-02-28 | $7700.00 | Window Closed / Lapsed |