US4263339A
Expired / Lapsed
US
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Process for the production of electroluminescent powders for display panels
Assignee: BBC Brown Boveri AG Germany
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Filing: 1979-06-25
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Granted: 1981-04-21
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Expires: 1999-06-25
Abstract
Abstract A process is provided for producing electroluminescent powders for use in information display panels of the type in which a monoparticle layer of electroluminescent powder is embedded in a high dielectric constant resin between two electrodes. The powders are zinc sulfide powders coactivated with aluminum and capable of emitting white light, as well as light of various colors. In the production of these powders they are treated to form an impermeable inorganic surface coating on the powder particles. The coating may be zinc phosphate or glass.
Inventors
- 👤 Albert G. Fischer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 13:50
CPC Classifications
H; H05; H05B; H05B33/00; H05B33/12; H05B33/14; H05B33/145; G; G09; G09G; G09G3/00; G09G3/20; G09G3/22; G09G3/30; H05B33/20; H05B33/22
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
160 words
In a process for producing electroluminescent powder for display devices having a monoparticle layer of electroluminescent powder embedded in a high dielectric constant resin between two electrodes, the steps of doping zinc sulfide powder with at least one halogen compound of a cation selected from a class consisting of aluminum, copper and magnesium, said halogen compound being dissolved in an organic solvent, heating the doped powder initially in an atmosphere of essentially stagnating hydrogen sulfide at a temperature of about 800° to 1050° C. to effect grain growth and then in a moving hydrogen sulfide gas stream to drive off halogen vapors, thereafter heating the powder to about 350° C. to 550° C. in molten sulfur and adding thereto a small amount of sulfide selected from the class consisting of copper, arsenic and antimony, dissolving the sulfur out of the powder and coating the particles of said powder with an impermeable passivating inorganic surface coating of zinc phosphate or glass.
Claim 2
Dependent Claim
160 words
In a process for producing electroluminescent powder for display devices having a monoparticle layer of electroluminescent powder embedded in a high dielectric constant resin between two electrodes, the steps of doping zinc sulfide powder with at least one halogen compound of a cation selected from a class consisting of aluminum, copper and magnesium, said halogen compound being dissolved in an organic solvent, heating the doped powder initially in an atmosphere of essentially stagnating hydrogen sulfide at a temperature of about 800° to 1050° C. to effect grain growth and then in a moving hydrogen sulfide gas stream to drive off halogen vapors, thereafter heating the powder to about 350° C. to 550° C. in molten sulfur and adding thereto a small amount of sulfide selected from the class consisting of copper, arsenic and antimony, dissolving the sulfur out of the powder and coating the particles of said powder with an impermeable passivating inorganic surface coating of zinc phosphate or glass.
Claim 3
Dependent Claim
20 words
The process of claim 1 wherein said powder is heated in molten sulfur under a nitrogen pressure of 100 bar.
Claim 4
Dependent Claim
16 words
The process of claim 1 wherein sulfur is dissolved out of the powder with carbon disulfide.
Claim 5
Dependent Claim
172 words
In a process for producing electroluminescent powder for display devices having a monoparticle layer of electroluminescent powder embedded in a high dielectric constant resin between two electrodes, the steps of doping zinc sulfide-zinc selenide powder with at least one halogen compound of a cation selected from the class consisting of aluminum, copper and magnesium, said halogen compound being dissolved in an organic solvent, heating the doped powder initially in an atmosphere of essentially stagnating hydrogen sulfide at a temperature of about 800° to 1050° C. to effect grain growth and then in a moving hydrogen sulfide gas stream to drive off halogen vapors, thereafter heating the powder to about 350° C. to 550° C. in a molten sulfur-selenium mixture of the same molar composition as the powder and adding thereto a small amount of sulfide selected from the class consisting of copper, arsenic and antimony, dissolving the sulfur-selenium mixture out of the powder and coating the particles of said powder with an impermeable, passivating inorganic surface coating of zinc phosphate or glass.
Claim 6
Dependent Claim
172 words
In a process for producing electroluminescent powder for display devices having a monoparticle layer of electroluminescent powder embedded in a high dielectric constant resin between two electrodes, the steps of doping zinc sulfide-zinc selenide powder with at least one halogen compound of a cation selected from the class consisting of aluminum, copper and magnesium, said halogen compound being dissolved in an organic solvent, heating the doped powder initially in an atmosphere of essentially stagnating hydrogen sulfide at a temperature of about 800° to 1050° C. to effect grain growth and then in a moving hydrogen sulfide gas stream to drive off halogen vapors, thereafter heating the powder to about 350° C. to 550° C. in a molten sulfur-selenium mixture of the same molar composition as the powder and adding thereto a small amount of sulfide selected from the class consisting of copper, arsenic and antimony, dissolving the sulfur-selenium mixture out of the powder and coating the particles of said powder with an impermeable, passivating inorganic surface coating of zinc phosphate or glass.
Claim 7
Dependent Claim
30 words
The process of claim 4 wherein said powder is heated in a molten sulfur-selenium mixture of the same molar composition as the powder under a nitrogen pressure of 100 bar.
Claim 8
Dependent Claim
18 words
The process of claim 4 wherein, after cooling, the sulfur-selenium mixture is dissolved out with potassium cyanide solution.
Claim 9
Dependent Claim
16 words
The process of claim 4 wherein said particles are coated by boiling them in phosphoric acid.
Claim 10
Dependent Claim
25 words
The process of claim 1 or 4 wherein said particles are coated by heating them in hydrogen peroxide and then boiling them in orthophosphoric acid.
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) | 1984-04-20 | 1984-10-20 | 1985-04-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-04-20 | 1988-10-20 | 1989-04-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-04-20 | 1992-10-20 | 1993-04-21 | $7700.00 | Window Closed / Lapsed |