US4447762A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electroluminescent displays
Assignee: EMI Ltd
•
Filing: 1982-07-07
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Granted: 1984-05-08
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Expires: 2002-07-07
Abstract
Abstract When a display incorporating electroluminescent (EL) device is switched on, the electrical resistance across electrodes and which indicates the moisture content of the EL layer is measured by electrical resistance measuring device. If the resistance is below a preset value corresponding to an unacceptable moisture content a current pulse source is activated to heat the EL layer and evaporate the moisture. The resistance is also measured periodically during continued use of the display.
Inventors
- 👤 Edward W. Williams
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 13:43
CPC Classifications
G; G09; G09F; G09F13/00; G09F13/20; G09F13/22; G05; G05D; G05D22/00; G05D22/02
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
50 words
An electroluminescent device including a number of electrically conducting electrodes, embedded in an insulating layer within said device, and means for measurement of the electrical resistance between said electrodes, including means to apply heat to the electroluminescent device in response to said electrical resistance becoming less than a preset level.
Claim 2
Dependent Claim
50 words
An electroluminescent device including a number of electrically conducting electrodes, embedded in an insulating layer within said device, and means for measurement of the electrical resistance between said electrodes, including means to apply heat to the electroluminescent device in response to said electrical resistance becoming less than a preset level.
Claim 3
Dependent Claim
18 words
A device according to claim 1, wherein the means to apply heat comprises a source of current pulses.
Claim 4
Dependent Claim
25 words
A device according to claim 1 which further comprises means to deactivate the means to apply heat when the electrical resistance exceeds a predetermined value.
Claim 5
Dependent Claim
17 words
A device according to claim 3, wherein the predetermined value of resistance corresponds to the preset level.
Claim 6
Dependent Claim
25 words
A device according to claim 1, wherein the measurement means periodically checks the electrical resistance between said electrodes during continuing use of the electroluminescent device.
Claim 7
Dependent Claim
13 words
A display unit incorporating at least one electroluminescent device according to claim 1.
Claim 8
Dependent Claim
66 words
A display unit incorporating a plurality of electroluminescent devices each including a number of electrically conducting electrodes embedded in an insulating layer within said device, a single means for measurement of the electrical resistance between the electrodes of each of the devices and a single means to apply heat to each of electroluminescent devices in response to said electrical resistance becoming less than a preset level.
Claim 9
Dependent Claim
66 words
A display unit incorporating a plurality of electroluminescent devices each including a number of electrically conducting electrodes embedded in an insulating layer within said device, a single means for measurement of the electrical resistance between the electrodes of each of the devices and a single means to apply heat to each of electroluminescent devices in response to said electrical resistance becoming less than a preset level.
References Cited (Backward Citations)
US2791723A
Cited
SU489273A1
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-05-08 | 1987-11-07 | 1988-05-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-05-08 | 1991-11-07 | 1992-05-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-05-08 | 1995-11-07 | 1996-05-08 | $7700.00 | Window Closed / Lapsed |