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US4296406A
Expired / Lapsed
US
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Pressure sensitive switch structure
Assignee: Unisys Corp
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Filing: 1979-12-28
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Granted: 1981-10-20
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Expires: 1999-12-28
Abstract
Abstract The present invention switch comprises a pair of electrodes separated by resilient resistive material which changes resistance several orders of magnitude in response to light pressure. Sensing and amplifying means are provided to detect a predetermined change in resistance. An array of a plurality of such switches may be arranged in a switching matrix to provide any desired form of switch controls or a keyboard for numerous electronic applications.
Inventors
- 👤 Billy J. Pearson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 07:47
CPC Classifications
H; H01; H01H; H01H13/00; H01H13/70; H01H13/78; H01H13/785; G; G01; G01L; G01L1/00; G01L1/20; G01L1/205; H01H13/702; H01H13/80; H01H2201/00; H01H2201/002; H01H2201/022; H01H2201/032; H01H2201/036; H01H2203/00; H01H2203/034; H01H2209/00; H01H2209/024; H01H2209/028; H01H2231/00; H01H2231/002; H01H2231/022; H01H2231/05
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
182 words
A pressure sensitive matrix switch device comprising: an insulative base, a first conductive pad means having a plurality of switch pads, a second conductive pad means, at least one of said pads being mounted on said base, a pressure sensitive conductive-resistive material intermediate said conductive pad means, said conductive-resistive material normally displaying a very high resistance therebetween when no pressure is applied, said conductive-resistive material displaying a low resistance therebetween when a light pressure is applied, means for applying pressure to said conductive pads to compress said conductive-resistive material and to change the resistance of said conductive-resistive material from a relatively high ohmic value to a relatively low ohmic value, voltage source means connected to the said second conductive pad means, said change of said conductive-resistive material from a relatively high ohmic value to a relatively low ohmic value for generating a voltage signal from one of said switch pads indicative of a particular switch device being operated, and logic encoder means coupled to said voltage signal for generating binary coded signals indicative of one of said matrix switch devices being operated.
Claim 2
Dependent Claim
182 words
A pressure sensitive matrix switch device comprising: an insulative base, a first conductive pad means having a plurality of switch pads, a second conductive pad means, at least one of said pads being mounted on said base, a pressure sensitive conductive-resistive material intermediate said conductive pad means, said conductive-resistive material normally displaying a very high resistance therebetween when no pressure is applied, said conductive-resistive material displaying a low resistance therebetween when a light pressure is applied, means for applying pressure to said conductive pads to compress said conductive-resistive material and to change the resistance of said conductive-resistive material from a relatively high ohmic value to a relatively low ohmic value, voltage source means connected to the said second conductive pad means, said change of said conductive-resistive material from a relatively high ohmic value to a relatively low ohmic value for generating a voltage signal from one of said switch pads indicative of a particular switch device being operated, and logic encoder means coupled to said voltage signal for generating binary coded signals indicative of one of said matrix switch devices being operated.
Claim 3
Dependent Claim
72 words
A pressure sensitive matrix switch device as set forth in claim 1 wherein said means for applying pressure to said conductive-resistive material comprises a plurality of insulative push-buttons mounted on a continuous insulative sheet, said second conductive pad means further comprises a continuous flexible conductive sheet underlying said insulative push-buttons, and individual leads connected to each of said first conductive switch pads for coupling said voltage signal to said logic encoder means.
Claim 4
Dependent Claim
22 words
A pressure sensitive matrix switch as set forth in claim 2 wherein said push-buttons comprise indicia printed on said continuous insulative sheet.
Claim 5
Dependent Claim
32 words
A pressure sensitive switch device as set forth in claim 2 wherein said conductive-resistive material further comprises a continuous sheet of sponge-like material intermediate said first and said second conductive pad means.
Claim 6
Dependent Claim
51 words
A pressure sensitive matrix switch device as set forth in claim 1 wherein said second conductive pad means further comprises, a continuous flexible separate conductive sheet underlying said push-buttons and overlaying said pressure sensitive conductive-resistive material, and said switch pads underlying said pressure sensitive conductive-resistive material and overlaying said insulated base.
Claim 7
Dependent Claim
38 words
A pressure sensitive matrix switch device as set forth in claim 5 wherein said conductive-resistive material further comprises a continuous thin sheet of solid carbon impregnated plastic sheet material intermediate said first and said second conductor pad means.
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) | 1984-10-19 | 1985-04-20 | 1985-10-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-10-19 | 1989-04-20 | 1989-10-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-10-19 | 1993-04-20 | 1993-10-20 | $7700.00 | Window Closed / Lapsed |