Patent US4859904A successfully refreshed from Google Patents.
US4859904A
Expired / Lapsed
US
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High contrast electroluminescent displays
Assignee: Phosphor Products Co Ltd
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Filing: 1988-05-24
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Granted: 1989-08-22
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Expires: 2008-05-24
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 black or dark powder back layer of electrically conductive material, and a second electrode film. Application of a voltage across the phosphor layer causes it to emit light. In this invention, the black powder back-layer significantly enhances the contrast of the panel.
Inventors
- 👤 Malcolm H. Higton
- 👤 Aron Vecht
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 02:14
CPC Classifications
H; H05; H05B; H05B33/00; H05B33/12; H05B33/22
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
106 words
An electroluminescent phosphor panel suitable for unidirectional voltage operation, comprising in serial order, a transparent electrically insulating substrate, a transparent first electrode film, a first layer in the form of a thin film of substantially insulating phosphor and a second layer which is a control layer of powder material, the improvement consisting in that: (A) the said thin film first layer is the sole light-emitting layer; and (B) the said powder material is: (i) inherently dark-colored, (ii) one of electrically conducting and semi-conducting, (iii) not a phosphor, and (iv) free of activator doping; and (C) the particles of said powder material are free of metallic coating.
Claim 2
Dependent Claim
106 words
An electroluminescent phosphor panel suitable for unidirectional voltage operation, comprising in serial order, a transparent electrically insulating substrate, a transparent first electrode film, a first layer in the form of a thin film of substantially insulating phosphor and a second layer which is a control layer of powder material, the improvement consisting in that: (A) the said thin film first layer is the sole light-emitting layer; and (B) the said powder material is: (i) inherently dark-colored, (ii) one of electrically conducting and semi-conducting, (iii) not a phosphor, and (iv) free of activator doping; and (C) the particles of said powder material are free of metallic coating.
Claim 3
Dependent Claim
112 words
An electroluminescent phosphor panel suitable for unidirectional voltage operation, comprising in serial order, a transparent electrically insulating substrate, a transparent first electrode film, a first layer in the form of a thin film of substantially insulating phosphor and a second layer which is a control layer of powder material, the improvement consisting in that: (A) the said thin film first layer is the sole light-emitting layer; and (B) the said powder material is: (i) inherently dark-colored, having a band gap of 1.8 eV, (ii) one of electrically conducting and semi-conducting, (iii) not a phosphor, (iv) free of activator doping; and (C) the particles of said powder material are free of metallic coating.
Claim 4
Dependent Claim
112 words
An electroluminescent phosphor panel suitable for unidirectional voltage operation, comprising in serial order, a transparent electrically insulating substrate, a transparent first electrode film, a first layer in the form of a thin film of substantially insulating phosphor and a second layer which is a control layer of powder material, the improvement consisting in that: (A) the said thin film first layer is the sole light-emitting layer; and (B) the said powder material is: (i) inherently dark-colored, having a band gap of 1.8 eV, (ii) one of electrically conducting and semi-conducting, (iii) not a phosphor, (iv) free of activator doping; and (C) the particles of said powder material are free of metallic coating.
Claim 5
Dependent Claim
131 words
An electroluminescent phosphor panel suitable for unidirectional voltage operation, comprising in serial order, a transparent electrically insulating substrate, a transparent first electrode film, a first layer in the form of a thin film of substantially insulating phosphor and a second layer which is a control layer of powder material, the improvement consisting in that: (A) the said thin film first layer is the sole light-emitting layer; and (B) the said powder material is: (i) inherently dark-colored, (ii) one of electrically conducting and semi-conducting, (iii) not a phosphor, (iv) 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 ; and (C) the particles of said powder material are free of metallic coating.
Claim 6
Dependent Claim
131 words
An electroluminescent phosphor panel suitable for unidirectional voltage operation, comprising in serial order, a transparent electrically insulating substrate, a transparent first electrode film, a first layer in the form of a thin film of substantially insulating phosphor and a second layer which is a control layer of powder material, the improvement consisting in that: (A) the said thin film first layer is the sole light-emitting layer; and (B) the said powder material is: (i) inherently dark-colored, (ii) one of electrically conducting and semi-conducting, (iii) not a phosphor, (iv) 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 ; and (C) the particles of said powder material are free of metallic coating.
Claim 7
Dependent Claim
111 words
An electroluminescent phosphor panel suitable for unidirectional voltage operation, comprising in serial order, a transparent electrically insulating substrate, a transparent first electrode film, a first layer in the form of a thin film of substantially insulating phosphor and a second layer which is a control layer of powder material, the improvement consisting in that: (A) the said thin film first layer is the sole light-emitting layer; and (B) the said powder material is MnO 2 powder free of metallic coating and free of activator doping, the said MnO 2 powder being an inherently dark-colored, electrically conducting, non-phosphor material; and (C) the particles of said powder material are free of metallic coating.
Claim 8
Dependent Claim
111 words
An electroluminescent phosphor panel suitable for unidirectional voltage operation, comprising in serial order, a transparent electrically insulating substrate, a transparent first electrode film, a first layer in the form of a thin film of substantially insulating phosphor and a second layer which is a control layer of powder material, the improvement consisting in that: (A) the said thin film first layer is the sole light-emitting layer; and (B) the said powder material is MnO 2 powder free of metallic coating and free of activator doping, the said MnO 2 powder being an inherently dark-colored, electrically conducting, non-phosphor material; and (C) the particles of said powder material are free of metallic coating.
Claim 9
Dependent Claim
162 words
An electroluminescent phosphor panel suitable for unidirectional voltage operation, comprising in serial order, a transparent electrically insulating substrate, a transparent first electrode film, a first layer in the form of a thin film of substantially insulating phosphor and a second layer which is a control layer of powder material, the improvement consisting in that: (A) the said thin film first layer is the sole light-emitting layer; and (B) the said powder material is: (i) inherently dark-colored, (ii) electrically conducting, (iii) not a phosphor, (iv) 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 ; and (C) the particles of said powder material are free of metallic coating; and (D) the said second layer is composed of discrete ridges separated from each other by furrows, and is effective for direct coupling to a source of electric power without the intermediation of an electrode.
Claim 10
Dependent Claim
162 words
An electroluminescent phosphor panel suitable for unidirectional voltage operation, comprising in serial order, a transparent electrically insulating substrate, a transparent first electrode film, a first layer in the form of a thin film of substantially insulating phosphor and a second layer which is a control layer of powder material, the improvement consisting in that: (A) the said thin film first layer is the sole light-emitting layer; and (B) the said powder material is: (i) inherently dark-colored, (ii) electrically conducting, (iii) not a phosphor, (iv) 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 ; and (C) the particles of said powder material are free of metallic coating; and (D) the said second layer is composed of discrete ridges separated from each other by furrows, and is effective for direct coupling to a source of electric power without the intermediation of an electrode.
Claim 11
Dependent Claim
35 words
A panel according to claim 1, wherein the powder of the second layer is selected from the group consisting of transition metal oxides, transition metal sulfides, rare earth metal oxides and rare earth metal sulfides.
Claim 12
Dependent Claim
19 words
A panel according to claim 1, wherein the powder of the second layer is selected from the metal chalcogenides.
Claim 13
Dependent Claim
18 words
A panel according to claim 1, wherein the powder of the second layer is selected from metal oxides.
Claim 14
Dependent Claim
18 words
A panel according to claim 1, wherein the powder of the second layer is selected from metal sulfides.
Claim 15
Dependent Claim
44 words
A panel according to claim 1, wherein the powder of the second 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 16
Dependent Claim
20 words
A panel according to claim 1, where the band gap of the said second layer is less than 1.8 eV.
Claim 17
Dependent Claim
24 words
A panel according to claim 1, which includes a second electrode in contact with the side of the second layer remote from the substrate.
Claim 18
Dependent Claim
21 words
A panel according to claim 1, wherein the second layer is composed of discrete ridges separated from each other by furrows.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 1992-08-21 | 1993-02-20 | 1993-08-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-08-21 | 1997-02-20 | 1997-08-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-08-21 | 2001-02-20 | 2001-08-22 | $7700.00 | Window Closed / Lapsed |