Patent US3668698A successfully refreshed from Google Patents.
US3668698A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Capacitive transducer
Assignee: Nortel Networks Ltd
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Filing: 1970-12-17
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Granted: 1972-06-06
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Expires: 1990-12-17
Abstract
Abstract A capacitive transducer, for a contactless switch, which utilizes an electret sandwiched between two conductors, one of which is a conductive elastomer. Depression of the conductive elastomer produces a voltage pulse across the two conductors which is utilized to turn on a field-effect transistor, thus providing a low impedance path for the switch.
Inventors
- 👤 Sayman Fadil Demirdjioghlou
- 👤 Robert Maarten Van Dyk
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 21:35
CPC Classifications
H; H04; H04M; H04M1/00; H04M1/02; H04M1/23; H03; H03K; H03K17/00; H03K17/94; H03K17/965; H03K17/975; H03K17/98
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
69 words
A capacitive transducer, for a contactless switch, comprising: a conductive base contact; an electret film having one surface in juxtaposition with said conductive base contact; and a conductive elastomer sheet means in juxtaposition with the other surface of the electret film, said conductive elastomer sheet means being flexible in a direction relative to the conductive base contact to alter capacitance therebetween so as to produce a voltage pulse thereacross.
Claim 2
Dependent Claim
69 words
A capacitive transducer, for a contactless switch, comprising: a conductive base contact; an electret film having one surface in juxtaposition with said conductive base contact; and a conductive elastomer sheet means in juxtaposition with the other surface of the electret film, said conductive elastomer sheet means being flexible in a direction relative to the conductive base contact to alter capacitance therebetween so as to produce a voltage pulse thereacross.
Claim 3
Dependent Claim
21 words
A capacitive transducer as defined in claim 1 in which the conductive elastomer sheet means is composed of conductive silicone rubber.
Claim 4
Dependent Claim
44 words
A contactless switch comprising a capacitive transducer as defined in claim 1 and further comprising: a field-effect transistor haVing gate, source and drain electrodes; the gate and source electrodes being connected in shunt with the conductive base contact and the conductive elastomer sheet means.
Claim 5
Dependent Claim
19 words
A contactless switch as defined in claim 3 further comprising a diode connected between the gate and source electrodes.
Claim 6
Dependent Claim
47 words
A contactless switch as defined in claim 3 further comprising a push-button, and a spring disposed between the push-button and the conductive elastomer sheet means, the push-button being moveable to compress the spring and thereby to depress the conductive elastomer sheet means towards the conductive base contact.
Claim 7
Dependent Claim
125 words
A capacitive transducer, for a contactless switch, comprising: a printed circuit board having at least one conductive contact on one side thereof; an electret film having one surface in juxtaposition with said one side; an insulated frame having one side disposed on the other surface of said electret film; a sheet of conductive elastomer positioned on the other side of said frame, said sheet having at least one protrusion extending through said frame in juxtaposition with said film and opposed said one conductive contact; and said sheet being depressable to displace said protrusion towards the electret film to increase the capacitance between the conductive contact and the sheet, so as to produce a voltage pulse thereacross due to the electrical charge on the electret film.
Claim 8
Dependent Claim
125 words
A capacitive transducer, for a contactless switch, comprising: a printed circuit board having at least one conductive contact on one side thereof; an electret film having one surface in juxtaposition with said one side; an insulated frame having one side disposed on the other surface of said electret film; a sheet of conductive elastomer positioned on the other side of said frame, said sheet having at least one protrusion extending through said frame in juxtaposition with said film and opposed said one conductive contact; and said sheet being depressable to displace said protrusion towards the electret film to increase the capacitance between the conductive contact and the sheet, so as to produce a voltage pulse thereacross due to the electrical charge on the electret film.
Claim 9
Dependent Claim
46 words
A capacitive transducer as defined in claim 6 which further comprises a push-button, and a spring disposed between the push-button and the side of the sheet opposite said protrusion, said push-button being moveable to compress the spring and thereby displace said protrusion towards said electret film.
Claim 10
Dependent Claim
44 words
A contactless switch comprising a capacitive transducer as defined in claim 6 and further comprising: a field-effect transistor having gate, source and drain electrodes, the gate and source electrodes being connected in shunt with the conductive base contact and the sheet of conductive elastomer.
Claim 11
Dependent Claim
19 words
A contactless switch as defined in claim 8 further comprising: a diode connected between the gate and source electrodes.
References Cited (Backward Citations)
US3293640A
Cited
US3308253A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-06-06 | 1975-12-06 | 1976-06-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-06-06 | 1979-12-06 | 1980-06-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-06-06 | 1983-12-06 | 1984-06-06 | $7700.00 | Window Closed / Lapsed |