Patent US4672264A successfully refreshed from Google Patents.
US4672264A
Expired / Lapsed
US
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High contrast electroluminescent display panels
Assignee: Phosphor Products Co Ltd
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Filing: 1985-06-04
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Granted: 1987-06-09
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Expires: 2005-06-04
Abstract
Abstract A d.c. or a.c. electroluminescent panel comprises a transparent substrate, a transparent first electrode film, a thin film phosphor layer, a control layer and a second electrode film. A black or dark colored material, less than 1 micron thick, is interposed between the thin film phosphor layer and the control layer to enhance the contrast of the panel whenever a voltage is applied across the thin film phosphor layer causing it to emit light.
Inventors
- 👤 Malcolm H. Higton
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 15:27
CPC Classifications
H; H05; H05B; H05B33/00; H05B33/12; H05B33/22
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
96 words
An electroluminescent phosphor panel suitable for both undirectional and alternating voltage operations comprising, in serial order, a transparent electrically insulating substrate, a transparent first electrode film, a first thin film layer of semi-insulating self-activated or activator-doped phosphor, a second layer of black or dark coloured, electrically resistive material, and a third layer comprising an electrically conducting powder control layer, the said second layer having an average thickness of less than 1 micron and effective to provide contrast enhancement and to allow injection of electrons thereacross from said powder control layer into said first thin film layer.
Claim 2
Dependent Claim
96 words
An electroluminescent phosphor panel suitable for both undirectional and alternating voltage operations comprising, in serial order, a transparent electrically insulating substrate, a transparent first electrode film, a first thin film layer of semi-insulating self-activated or activator-doped phosphor, a second layer of black or dark coloured, electrically resistive material, and a third layer comprising an electrically conducting powder control layer, the said second layer having an average thickness of less than 1 micron and effective to provide contrast enhancement and to allow injection of electrons thereacross from said powder control layer into said first thin film layer.
Claim 3
Dependent Claim
31 words
A panel according to claim 1 and wherein said second layer comprises a material selected from the group consisting of ZnTe, CdTe, CdSe, Chalcogenide glass and Sb 2 S 3 .
Claim 4
Dependent Claim
26 words
A panel according to claim 1 which further comprises a second electrode film in contact with the side of the third layer remote from the substrate.
Claim 5
Dependent Claim
15 words
A panel according to claim 1, wherein said second layer is a thin film layer.
Claim 6
Dependent Claim
35 words
A panel according to claim 1, wherein the powder of the third layer is selected from the group consisting of transition metal oxides, transition metal sulfides, rare earth metal oxides and rare earth metal sulfides.
Claim 7
Dependent Claim
19 words
A panel according to claim 1, wherein the powder of the third layer is selected from the metal chalcogenides.
Claim 8
Dependent Claim
18 words
A panel according to claim 1, wherein the powder of the third layer is selected from metal oxides.
Claim 9
Dependent Claim
18 words
A panel according to claim 1, wherein the powder of the third layer is selected from metal sulfides.
Claim 10
Dependent Claim
44 words
A panel according to claim 1, wherein the powder of the third layer is selected from the group consisting of PbS, PbO, CuO, MnO 2 , Tb 4 O 7 , Eu 2 O 3 , PrO 2 and Ce 2 S 3 .
Claim 11
Dependent Claim
27 words
A panel according to claim 1, wherein the powder of the third layer is selected from the group consisting of non-emitting phosphor materials and non-activator-doped phosphor materials.
Claim 12
Dependent Claim
19 words
A panel according to claim 1, wherein the band gap of the third layer is less than 2 eV.
Claim 13
Dependent Claim
19 words
A panel according to claim 1, wherein the band gap of the third layer is less than 1.8 eV.
Claim 14
Dependent Claim
21 words
A panel according to claim 1, wherein the third layer is composed of discrete ridges separated from each other by furrows.
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GB2017138A
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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) | 1990-06-08 | 1990-12-08 | 1991-06-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-06-08 | 1994-12-08 | 1995-06-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-06-08 | 1998-12-08 | 1999-06-09 | $7700.00 | Window Closed / Lapsed |