US4831304A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Sensors
Assignee: Gemalto Terminals Ltd
•
Filing: 1988-01-21
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Granted: 1989-05-16
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Expires: 2008-01-21
Abstract
Abstract A solid sensor, for sensing a physical parameter such as pressure, comprises a resonantly vibratable beam formed across a cavity in a substrate by micro-machining, and arranged such that changes in the parameter vary its resonant frequency. The beam either consists of or has deposited on it a material exhibiting piezo-electric effect, so that vibration of the beam can be excited by using the effect. This is achieved using light, either by forming a photodiode in the substrate in or near the beam, so that illuminating the photodiode causes a voltage to be applied to the beam, or, in the case where the piezo-electric material exhibits surface piezo-electric effect, by directly illuminating the beam.
Inventors
- 👤 Howard A. Dorey
- 👤 Bronislaw J. Suski
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 02:58
CPC Classifications
G; G01; G01L; G01L9/00; G01L9/0001; G01L9/0008; G01L9/0022; G01L9/0023; G01L1/00; G01L1/16; G01L1/162; G01L1/167; G01L1/18; G01L1/183; G01L1/186; G01L9/0019; G01L9/002
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
90 words
A sensor for sensing a physical parameter, the sensor comprising: a resonantly vibratable element, formed in a substrate; means for exciting resonant vibration of the element; and means for applying the parameter to the element so as to vary the frequency of vibration thereof in dependence upon the parameter; wherein the element comprises a material which exhibits surface piezo-electric effect; and the exciting means includes means for directing light of suitable wavelength onto the element so as to induce said resonant vibration thereof by virtue of said surface piezo-electric effect.
Claim 2
Dependent Claim
90 words
A sensor for sensing a physical parameter, the sensor comprising: a resonantly vibratable element, formed in a substrate; means for exciting resonant vibration of the element; and means for applying the parameter to the element so as to vary the frequency of vibration thereof in dependence upon the parameter; wherein the element comprises a material which exhibits surface piezo-electric effect; and the exciting means includes means for directing light of suitable wavelength onto the element so as to induce said resonant vibration thereof by virtue of said surface piezo-electric effect.
Claim 3
Dependent Claim
24 words
A sensor as claimed in claim 1, wherein the element is formed in a substrate of crystalline material which exhibits said surface piezo-electric effect.
Claim 4
Dependent Claim
23 words
A sensor as claimed in claim 2, wherein said material is selected from the group comprising zinc oxide, cadmium sulphide and gallium arsenide.
Claim 5
Dependent Claim
24 words
A sensor as claimed in claim 1, wherein the element is formed in a silicon substrate, and said material is sputtered onto said element.
Claim 6
Dependent Claim
13 words
A sensor as claimed in claim 4, wherein said material is zinc oxide.
Claim 7
Dependent Claim
21 words
A sensor as claimed claim 1, wherein the resonantly vibratable element comprises a beam extending across a recess in the substrate.
Claim 8
Dependent Claim
16 words
A sensor as claimed in claim 1, wherein the resonantly vibratable element is formed by micro-machining.
References Cited (Backward Citations)
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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) | 1992-05-15 | 1992-11-14 | 1993-05-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-05-15 | 1996-11-14 | 1997-05-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-05-15 | 2000-11-14 | 2001-05-16 | $7700.00 | Window Closed / Lapsed |