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US5541570A
Expired / Lapsed
US
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Force sensing ink, method of making same and improved force sensor
Assignee: Breed Automotive Technology Inc
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Filing: 1994-12-09
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Granted: 1996-07-30
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Expires: 2014-12-09
Abstract
Abstract An improved carbon-free force sensitive ink for a force sensor. The ink when deposited and dried can function at temperatures of up to 350° F. and pressures of up to 10,000 psi. The preferred ink includes a thermoplastic polyimide binder, conductive particles, intrinsically semi-conductive particles, and dielectric particles, all of an average particle size of 1.0 micron or less. The preferred semi-conductive particles are molybdenum disulfide, ferric and ferrous oxide particles. The preferred conductive particles are conductive metal oxide compounds that deviate from stoichiometry based on an oxygen value of two, such as conductive tin oxide, Fe 3 O 4 iron oxide, and mixtures of them. The preferred dielectric particles are silica. The binder is present in an amount of 20 to 80% by volume. The sensor and a method of making the sensor are also disclosed.
Inventors
- 👤 Donald J. McDowell
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 15:50
CPC Classifications
H; H01; H01C; H01C10/00; H01C10/10; H01C10/106
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
86 words
A carbon-free force sensing ink for being deposited in a thin layer between a pair of conductors, each conductor being disposed on a support surface, said force sensing ink having a resistance which varies as a function of the force applied thereagainst, said force sensing ink being usable in force sensing applications at temperatures of from 150° F. to 350° F. and comprising a high temperature binder; intrinsically semi-conductive particles; and conductive particles comprising a conductive metal oxide compound based on an oxygen value of two.
Claim 2
Dependent Claim
86 words
A carbon-free force sensing ink for being deposited in a thin layer between a pair of conductors, each conductor being disposed on a support surface, said force sensing ink having a resistance which varies as a function of the force applied thereagainst, said force sensing ink being usable in force sensing applications at temperatures of from 150° F. to 350° F. and comprising a high temperature binder; intrinsically semi-conductive particles; and conductive particles comprising a conductive metal oxide compound based on an oxygen value of two.
Claim 3
Dependent Claim
33 words
A carbon free, force sensing ink in accordance with claim 1, and where said conductive particles comprise one of conductive tin oxide particles, Fe 3 O 4 iron oxide particles and mixtures thereof.
Claim 4
Dependent Claim
15 words
A carbon-free, force sensing ink in accordance with claim 1, and further comprising dielectric particles.
Claim 5
Dependent Claim
27 words
A carbon-free, force sensing ink in accordance with claim 3, and wherein said dielectric particles are silica having an average particle size of 10 microns or less.
Claim 6
Dependent Claim
19 words
A carbon-free, force sensing ink in accordance with claim 1, and wherein said semi-conductive particles are molybdenum disulfide particles.
Claim 7
Dependent Claim
27 words
A carbon-free, force sensing ink in accordance with claim 1, and wherein all of said particles are of an average particle size of 10 microns or less.
Claim 8
Dependent Claim
21 words
A carbon-free, force sensing ink in accordance with claim 1, and wherein said high temperature binder is a thermoplastic polyimide resin.
Claim 9
Dependent Claim
39 words
A carbon-free, force sensing ink in accordance with claim 1, and wherein said conductive and semi-conductive particles are present in a combined concentration of at least 20% by volume of the dried ink when deposited in a thin layer.
Claim 10
Dependent Claim
53 words
A carbon free, force sensing ink in accordance with claim 8, and wherein the binder is present in a combined amount of from 20 to 80% by volume and said conductive and semi-conductive particles are present in a combined amount of from 80 to 20% by volume when deposited in a thin layer.
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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) | 1999-07-30 | 2000-01-29 | 2000-07-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2003-07-30 | 2004-01-29 | 2004-07-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2007-07-30 | 2008-01-29 | 2008-07-30 | $7700.00 | Window Closed / Lapsed |