US5495137A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Proximity sensor utilizing polymer piezoelectric film with protective metal layer
Assignee: Measurement Specialties Inc
•
Filing: 1994-08-31
•
Granted: 1996-02-27
•
Expires: 2014-08-31
Abstract
Abstract An ultrasonic proximity sensor particularly suited for outdoor environments having a transducer including a polymer piezoelectric film bonded to a protective metal layer. The transducer is mounted in the sensor housing so that the protective metal layer is exposed to the environment through a window of the sensor housing. The transducer can be implemented as an asymmetric bimorph structure, having an electrode bonded to a surface of the polymer piezoelectric film opposite the protective metal layer and between support members. Deformation of the polymer piezoelectric film between the protective metal layer and the electrode occurs upon application of a voltage thereto, generating an ultrasonic wave. The transducer can also be used as a receiver, generating an output voltage from the electrode upon impingement of an ultrasonic wave upon the protective metal layer. The transducer can also be implemented as a curved length mode transducer including an arcuate shaped support member for supporting the polymer piezoelectric film to be curved between the support members. The radius of the curved length mode transducer is selected so that the transducer can be resonant at the resonance frequency of the curved length mode, therefore vibrating at high frequency to generate an ultrasonic wave.
Inventors
- 👤 Kyung T. Park
- 👤 Minoru Toda
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 13:01
CPC Classifications
B; B06; B06B; B06B1/00; B06B1/02; B06B1/06; B06B1/0688; B06B1/0692; G; G01; G01D; G01D11/00; G01D11/24; G01D11/245; G01D5/00; G01D5/48; G01S; G01S15/00; G01S15/02; G01S15/87; G01S15/88; G01S15/93; G01S15/931; G01S7/00; G01S7/52; G01S7/521; G01S7/523; G01S7/524; G10; G10K; G10K9/00; G10K9/12; G10K9/122; G10K9/125; G01S2015/937; G01S2015/938; Y; Y10; Y10S; Y10S310/00; Y10S310/80
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
127 words
A transducer assembly for a proximity sensor comprising: a polymer piezoelectric film having opposing first and second surfaces, said second surface of said polymer piezoelectric film being secured at first and second ends in a first direction to respective first and second support members; a first electrode bonded to said first surface of said polymer piezoelectric film; a polyester spacer film bonded to said first electrode; a metal protective layer bonded to said polyester spacer film; a second electrode bonded to said second surface of said polymer piezoelectric film spaced from and intermediate said first and second support members in the elongated direction; and voltage supply means for applying a voltage across said first and second electrodes to radiate an ultrasonic wave from said protective metal layer.
Claim 2
Dependent Claim
127 words
A transducer assembly for a proximity sensor comprising: a polymer piezoelectric film having opposing first and second surfaces, said second surface of said polymer piezoelectric film being secured at first and second ends in a first direction to respective first and second support members; a first electrode bonded to said first surface of said polymer piezoelectric film; a polyester spacer film bonded to said first electrode; a metal protective layer bonded to said polyester spacer film; a second electrode bonded to said second surface of said polymer piezoelectric film spaced from and intermediate said first and second support members in the elongated direction; and voltage supply means for applying a voltage across said first and second electrodes to radiate an ultrasonic wave from said protective metal layer.
Claim 3
Dependent Claim
13 words
The transducer assembly of claim 1, wherein said metal protective layer comprises brass.
Claim 4
Dependent Claim
19 words
The transducer assembly of claim 2, wherein said metal protective layer is within a range of 50-125 microns thick.
Claim 5
Dependent Claim
31 words
The transducer assembly of claim 1, wherein a width of said second electrode in the first direction is 1.9 mm and a resonant frequency of the transducer assembly is 40 kHz.
Claim 6
Dependent Claim
24 words
The transducer assembly of claim 4, wherein said polyester spacer film is 250 microns thick and said polymer piezoelectric film is 110 microns thick.
Claim 7
Dependent Claim
14 words
The transducer assembly of claim 1, wherein said polymer piezoelectric film comprises poly-vinylidene fluoride.
Claim 8
Dependent Claim
12 words
The transducer assembly of claim 1, wherein said polyester film comprises Mylar®.
Claim 9
Dependent Claim
44 words
The transducer assembly of claim 1, wherein a resonant frequency of the transducer assembly is determined in accordance with a width of said second electrode in the first direction, a thickness of said polyester spacer film and a thickness of said polymer piezoelectric film.
Claim 10
Dependent Claim
146 words
A transducer assembly for a proximity sensor comprising: a polymer piezoelectric film having opposing first and second surfaces, said second surface of said polymer piezoelectric film being secured at first and second ends in a first direction to respective first and second support members; a first electrode bonded to said first surface of said polymer piezoelectric film; a polyester spacer film bonded to said first electrode; a metal protective layer bonded to said polyester spacer film; a second electrode bonded to said second surface of said polymer piezoelectric film intermediate said first and second support members in the first direction; voltage supply means for applying a voltage across said first and second electrodes to radiate an ultrasonic wave from said protective metal layer; and a third support member having an arcuate support surface for supporting said polymer piezoelectric film between said first and second support members.
Claim 11
Dependent Claim
146 words
A transducer assembly for a proximity sensor comprising: a polymer piezoelectric film having opposing first and second surfaces, said second surface of said polymer piezoelectric film being secured at first and second ends in a first direction to respective first and second support members; a first electrode bonded to said first surface of said polymer piezoelectric film; a polyester spacer film bonded to said first electrode; a metal protective layer bonded to said polyester spacer film; a second electrode bonded to said second surface of said polymer piezoelectric film intermediate said first and second support members in the first direction; voltage supply means for applying a voltage across said first and second electrodes to radiate an ultrasonic wave from said protective metal layer; and a third support member having an arcuate support surface for supporting said polymer piezoelectric film between said first and second support members.
Claim 12
Dependent Claim
26 words
The transducer assembly of claim 9, addition-ally including a gap formed between said arcuate support surface of said third support member and said polymer piezoelectric film.
Claim 13
Dependent Claim
26 words
The transducer assembly of claim 10, addition-ally including an air cavity formed along a rear face of said third support member opposite said arcuate support surface.
Claim 14
Dependent Claim
24 words
The transducer assembly of claim 11, said third support member having holes therethrough for allow-ing air flow between said gap and said air cavity.
Claim 15
Dependent Claim
22 words
The transducer assembly of claim 9, wherein said arcuate support surface of said third support member is convex in the elongated direction.
Claim 16
Dependent Claim
185 words
A proximity sensor unit comprising: a polymer piezoelectric film having opposing first and second surfaces, said second surface of said polymer piezoelectric film being secured in a first direction to respective first and second support members; a first electrode bonded to said first surface of said polymer piezoelectric film; a polyester spacer film bonded to said first electrode; a metal protective layer bonded to said polyester spacer film; a plurality of second electrodes of first predetermined width in the first direction bonded to said second surface of said polymer piezoelectric film between said first and second support members; a plurality of isolation members bonded to said second surface of said polymer piezoelectric film for isolating said plurality of second electrodes from each other in the first direction, said plurality of second electrodes respectively being bonded to said second surface spaced from and intermediate said plurality of isolation members and said first and second support members; and voltage supply means for applying a voltage across each of said plurality of second electrodes and said first electrode to radiate an ultrasonic wave from said protective metal layer.
Claim 17
Dependent Claim
185 words
A proximity sensor unit comprising: a polymer piezoelectric film having opposing first and second surfaces, said second surface of said polymer piezoelectric film being secured in a first direction to respective first and second support members; a first electrode bonded to said first surface of said polymer piezoelectric film; a polyester spacer film bonded to said first electrode; a metal protective layer bonded to said polyester spacer film; a plurality of second electrodes of first predetermined width in the first direction bonded to said second surface of said polymer piezoelectric film between said first and second support members; a plurality of isolation members bonded to said second surface of said polymer piezoelectric film for isolating said plurality of second electrodes from each other in the first direction, said plurality of second electrodes respectively being bonded to said second surface spaced from and intermediate said plurality of isolation members and said first and second support members; and voltage supply means for applying a voltage across each of said plurality of second electrodes and said first electrode to radiate an ultrasonic wave from said protective metal layer.
Claim 18
Dependent Claim
82 words
The proximity sensor unit of claim 14, further comprising: a third support member on which said second surface of said polymer piezoelectric film is secured; a third electrode of second predetermined width in the first direction bonded to said second surface of said polymer piezoelectric layer spaced from and intermediate said first and third support members; and output means for outputting a voltage indicative of impingement of an ultrasonic wave on said metal protective layer in a vicinity of said third electrode.
References Cited (Backward Citations)
US3093760A
Cited
US3396366A
Cited
US3816774A
Cited
US4015232A
Cited
US4056742A
Cited
US4675959A
Cited
US4322877A
Cited
US4278962A
Cited
US5028920A
Cited
US4636997A
Cited
US4803670A
Cited
US4924131A
Cited
US4910512A
Cited
US4980869A
Cited
US5059946A
Cited
US4967180A
Cited
US5076384A
Cited
US5160927A
Cited
US5373213A
Cited
US5356500A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1999-02-26 | 1999-08-28 | 2000-02-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2003-02-26 | 2003-08-28 | 2004-02-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2007-02-26 | 2007-08-28 | 2008-02-27 | $7700.00 | Window Closed / Lapsed |