Patent US4383194A successfully refreshed from Google Patents.
US4383194A
Expired / Lapsed
US
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Electro-acoustic transducer element
Assignee: Toray Industries Inc
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Filing: 1980-04-23
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Granted: 1983-05-10
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Expires: 2000-04-23
Abstract
Abstract Electro-acoustic transducer element having its resonant frequency in a lower frequency range advantageously usable for diagnostic purposes comprises a polymeric piezoelectric film such as polyvinylidene fluoride film being coupled with an additional layer having a thickness specified in relation to the wavelength of sound waves within the additional layer at the free resonant frequency of the polymeric piezoelectric film, the additional layer having an acoustic impedance related to the acoustic impedance of the polymeric piezoelectric film.
Inventors
- 👤 Hiroji Ohigashi
- 👤 Joshiharu Nakanishi
- 👤 Miyo Suzuki
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 12:00
CPC Classifications
G; G10; G10K; G10K11/00; G10K11/02; B; B06; B06B; B06B1/00; B06B1/02; B06B1/06; B06B1/0688; Y; Y10; Y10S; Y10S310/00; Y10S310/80
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
96 words
An improved electro-acoustic transducer element comprising a polymeric piezoelectric film having an acoustic impedance Z o , elements functioning as electrodes for the film, an additional layer having an acoustic impedance Z coupled to the acoustic emanation side of the film and having a thickness of from 0.5 μm to 3λ/8 in which λ refers to the wavelength of sound waves within the additional layer at the free resonant frequency of the film, and the acoustic impedance Z of the additional layer being not less than two times the acoustic impedance Z o of the film.
Claim 2
Dependent Claim
96 words
An improved electro-acoustic transducer element comprising a polymeric piezoelectric film having an acoustic impedance Z o , elements functioning as electrodes for the film, an additional layer having an acoustic impedance Z coupled to the acoustic emanation side of the film and having a thickness of from 0.5 μm to 3λ/8 in which λ refers to the wavelength of sound waves within the additional layer at the free resonant frequency of the film, and the acoustic impedance Z of the additional layer being not less than two times the acoustic impedance Z o of the film.
Claim 3
Dependent Claim
106 words
An improved electro-acoustic transducer element comprising a polymeric piezoelectric film having acoustic impedance Z o , elements functioning as electrodes for the film, an additional comparatively thin layer having an acoustic impedance Z coupled to the side opposite to the acoustic emanation side of the film and having a thickness less than the film and of from 0.5 μm to 1λ/16 in which λ refers to the wavelength of sound waves in the additional layer at the free resonant frequency of the film, and the acoustic impedance Z of the additional layer being not less than two times the acoustic impedance Z o of the film.
Claim 4
Dependent Claim
106 words
An improved electro-acoustic transducer element comprising a polymeric piezoelectric film having acoustic impedance Z o , elements functioning as electrodes for the film, an additional comparatively thin layer having an acoustic impedance Z coupled to the side opposite to the acoustic emanation side of the film and having a thickness less than the film and of from 0.5 μm to 1λ/16 in which λ refers to the wavelength of sound waves in the additional layer at the free resonant frequency of the film, and the acoustic impedance Z of the additional layer being not less than two times the acoustic impedance Z o of the film.
Claim 5
Dependent Claim
21 words
An improved electro-acoustic transducer element as claimed in claim 1 or 2, in which said additional layer is made of metal.
Claim 6
Dependent Claim
30 words
An improved electro-acoustic transducer element as claimed in claim 3 in which said additional layer functions as one of said electrode elements as well as functioning as said additional layer.
Claim 7
Dependent Claim
50 words
An improved electro-acoustic transducer element as claimed in claim 3 in which said metal forming said additional layer is chosen from a group consisting of Al, Cu, Ag, Sn, Au, Pb, Ni, Ti, Cr, Fe, Zn, In, Mo, and alloys whose constituents include at least one metal of said group.
Claim 8
Dependent Claim
43 words
An improved electro-acoustic transducer element as claimed in claim 1 or 2, in which said film is made of a material chosen from a group consisting of polyvinylidene fluoride, copolymers of polyvinylidene fluoride, polyvinyl chloride, acrylonitrile polymers, and polymers including powdered ferroelectric ceramic.
Claim 9
Dependent Claim
30 words
An improved electro-acoustic transducer element as claimed in claim 1 or 2, further comprising a second additional layer which is made of polymeric material coupled to said electro-acoustic transducer element.
Claim 10
Dependent Claim
38 words
An improved electro-acoustic transducer element as claimed in claim 7 in which the acoustic impedance Z p of said second additional layer is related to said acoustic impedance Z o of said film as follows: 0.2<Z.sub.p /Z.sub.o <2.
Claim 11
Dependent Claim
43 words
An improved electro-acoustic transducer element as claimed in claim 8 in which said second additional layer is made of a material chosen from a group consisting of polyethylene terephthalate, polycarbonate, PMMA, polystyrene, ABS, polyethylene, polyvinyl chloride, polyimide, polyamide, aromatic polyamide, and polyvinylidene fluoride.
Claim 12
Dependent Claim
28 words
An improved electro-acoustic transducer element as claimed in claim 1 or 2, further comprising a reflector plate which is made of metal coupled to said electro-acoustic transducer element.
Claim 13
Dependent Claim
30 words
An improved electro-acoustic transducer element as claimed in claim 10 in which said reflector plate is made of a material chosen from a group consisting of Au, Cu, and W.
Claim 14
Dependent Claim
22 words
An improved electro-acoustic transducer element as claimed in claim 1 or 2, further comprising a holder coupled to said electro-acoustic transducer element.
Claim 15
Dependent Claim
19 words
An improved electro-acoustic transducer element as claimed in claim 12 in which said holder is made of a polymer.
Claim 16
Dependent Claim
28 words
An improved electro-acoustic transducer element as claimed in claim 13 in which said polymer is chosen from a group consisting of PMMA, polystyrene, ABS, bakelite, and epoxy resin.
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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) | 1986-05-09 | 1986-11-08 | 1987-05-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-05-09 | 1990-11-08 | 1991-05-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-05-09 | 1994-11-08 | 1995-05-10 | $7700.00 | Window Closed / Lapsed |