US3590371A
Expired / Lapsed
US
⏱️ 0.0 years remaining
A method utilizing the color change with temperature of a material for detecting discontinuities in a conductor member embedded within a windshield
Assignee: PPG Industries Inc
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Filing: 1969-12-31
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Granted: 1971-06-29
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Expires: 1989-12-31
Abstract
Abstract Circuit discontinuities in conductor members embedded in pieces of glass, such as windshields, are detected by placing in operative association with the glass a stratum of cholestericphase liquid-crystal material having appropriate color-change temperature-range characteristics. When current is passed through the conductors, color changes are observed in the vicinities of the operating conductors. By using for the cholesteric-phase liquid-crystal material a mixture of at least first and second ingredients, with the first and second ingredients spanning respectively different portions of the temperature range from about 20* C. to about 32* C., desirable and useful indications are rapidly obtained without the use of particular testingenvironment conditions or particular glass-storage conditions.
Inventors
- 👤 Hugh E Shaw Jr
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 08:45
CPC Classifications
G; G01; G01R; G01R31/00; G01R31/50; G01R31/54; G01R31/52; G01R31/58
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
129 words
A method of detecting discontinuities in at least one electric-circuit conductor member embedded within a sheet of glass that comprises: sandwiching a stratum of cholesteric-phase liquid-crystal material, said material having a color-change temperature range above the temperature of the environment of testing, between two strata of flexible and substantially transparent material to form a sandwich, bringing the sandwich so formed into operative association with said sheet of glass while said sandwich overlies said at least one conductor member, applying electrical current to said at least one conductor member to cause a color change in the liquid-crystal material adjacent any continuous at least one conductor member and observing said liquid-crystal material to detect any lack of color change adjacent to said at least one conductor member which indicates a discontinuity.
Claim 2
Independent Claim
129 words
A method of detecting discontinuities in at least one electric-circuit conductor member embedded within a sheet of glass that comprises: sandwiching a stratum of cholesteric-phase liquid-crystal material, said material having a color-change temperature range above the temperature of the environment of testing, between two strata of flexible and substantially transparent material to form a sandwich, bringing the sandwich so formed into operative association with said sheet of glass while said sandwich overlies said at least one conductor member, applying electrical current to said at least one conductor member to cause a color change in the liquid-crystal material adjacent any continuous at least one conductor member and observing said liquid-crystal material to detect any lack of color change adjacent to said at least one conductor member which indicates a discontinuity.
Claim 3
Dependent Claim
27 words
A method as defined in claim 1, characterized in that said liquid-crystal material has a color-change temperature range at temperatures between about 20* C. and 32* C.
Claim 4
Dependent Claim
79 words
A method as defined in claim 1, characterized in that cholesteric-phase liquid-crystal material comprises a mixture of a first ingredient and a second ingredient, said first ingredient having a color-change temperature range in the lower portion of the temperature range of from 20* to 32* C., and in that said second ingredient comprises a cholesteric-phase liquid-crystal material having a color-change temperature range in the upper portion of the temperature range extending from about 20* C. to about 32* C.
References Cited (Backward Citations)
US2642481A
Cited
US2673325A
Cited
US2710274A
Cited
US2945305A
Cited
US3114836A
Cited
US3396335A
Cited
US3501698A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-06-28 | 1974-12-28 | 1975-06-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-06-28 | 1978-12-28 | 1979-06-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-06-28 | 1982-12-28 | 1983-06-29 | $7700.00 | Window Closed / Lapsed |