US5601751A
Expired / Lapsed
US
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Manufacturing process for high-purity phosphors having utility in field emission displays
Assignee: Micron Technology Inc
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Filing: 1995-06-08
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Granted: 1997-02-11
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Expires: 2015-06-08
Abstract
Abstract A process is provided for manufacturing high-purity phosphors having utility in field emission displays. The high-purity phosphor is a host lattice infiltrated by a dopant that activates luminescent properties therein. The lattice and dopant are initially milled together to reduce their average particle size while simultaneously achieving complete mixing between the lattice and the dopant. The resulting mixture is maintained free of a flux or substantially any other treatment agent capable of contaminating the phosphor and placed in a heating vessel formed from a substantially impervious contaminant-free material. The mixture is heated to a high temperature effectuating thorough infiltration of the dopant into the lattice structure. The use of an impervious contaminant-free heating vessel and the exclusion of flux or other treatment agents from the mixture avoids undesirable contamination and undue particle size growth of the phosphor product during the manufacture thereof. Accordingly, product is a high-purity phosphor having a small average particle size, yet exhibiting sufficient luminescent efficiencies for utility in field emission displays as a luminescent coating for the anode screen.
Inventors
- 👤 Charles M. Watkins
- 👤 Surjit S. Chadha
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 09:04
CPC Classifications
C; C09; C09K; C09K11/00; C09K11/08; C09K11/0805; C09K11/0827
Claims Analysis
Total Claims: 25
Claim 1
Independent Claim
145 words
A process for preparing a high-purity phosphor having utility as a luminescent in a field emission display, said process comprising: providing a host lattice starting material and a dopant starting material; combining said host lattice starting material and said dopant starting material in a precursor mixture having an initial average particle size and substantially free of any contaminant-generating components containing a Group IA ion or a Group IIA ion; processing said precursor mixture to obtain a sized precursor mixture having an average precursor particle size less than about 2 microns; placing said sized precursor mixture in a heat treatment vessel formed from platinum; and heating said sized precursor mixture in said heat treatment vessel to a temperature between about 1200° C. and 2000° C. for a time sufficient to infiltrate said dopant starting material into said host lattice starting material, thereby producing a high-purity phosphor.
Claim 2
Dependent Claim
145 words
A process for preparing a high-purity phosphor having utility as a luminescent in a field emission display, said process comprising: providing a host lattice starting material and a dopant starting material; combining said host lattice starting material and said dopant starting material in a precursor mixture having an initial average particle size and substantially free of any contaminant-generating components containing a Group IA ion or a Group IIA ion; processing said precursor mixture to obtain a sized precursor mixture having an average precursor particle size less than about 2 microns; placing said sized precursor mixture in a heat treatment vessel formed from platinum; and heating said sized precursor mixture in said heat treatment vessel to a temperature between about 1200° C. and 2000° C. for a time sufficient to infiltrate said dopant starting material into said host lattice starting material, thereby producing a high-purity phosphor.
Claim 3
Dependent Claim
37 words
A process for preparing a high-purity phosphor as recited in claim 1 wherein said host lattice starting material is selected from the group consisting of silicates, aluminates, oxides, gallates, vandates, tungstates, phosphates, fluorides, oxysulfides, and mixtures thereof.
Claim 4
Dependent Claim
30 words
A process for preparing a high-purity phosphor as recited in claim 1 wherein said dopant starting material is selected from the group consisting of lanthanides, transition metals and mixtures thereof.
Claim 5
Dependent Claim
23 words
A process for preparing a high-purity phosphor as recited in claim 1 wherein said high-purity phosphor is a binary or a ternary phosphor.
Claim 6
Dependent Claim
29 words
A process for preparing a high-purity phosphor as recited in claim 1 wherein said sized precursor mixture is heated to a temperature between about 1400° C. and 1800° C.
Claim 7
Dependent Claim
24 words
A process for preparing a high-purity phosphor as recited in claim 1 wherein said average precursor particle size is less than about 1 micron.
Claim 8
Dependent Claim
33 words
A process for preparing a high-purity phosphor as recited in claim 1 wherein said phosphor has an average product particle size no greater than about 100% larger than said average precursor particle size.
Claim 9
Dependent Claim
33 words
A process for preparing a high-purity phosphor as recited in claim 1 wherein said phosphor has an average product particle size no greater than about 50% larger than said average precursor particle size.
Claim 10
Dependent Claim
17 words
A process for preparing a high-purity phosphor as recited in claim 1 wherein said components are fluxes.
Claim 11
Dependent Claim
55 words
A process for preparing a high-purity phosphor as recited in claim 1 wherein said precursor mixture is processed to obtain said sized precursor mixture by milling said precursor mixture in a reciprocating mill, thereby reducing said initial average particle size of said precursor mixture to said average precursor particle size of said sized precursor mixture.
Claim 12
Dependent Claim
157 words
A process for manufacturing an anode of a field emission display having a high-purity phosphor coating, said process comprising: providing a host lattice starting material and a dopant starting material; combining said host lattice starting material and said dopant starting material in a precursor mixture having an initial average particle size and substantially free of any contaminant-generating components containing a Group IA ion or a Group IIA ion; processing said precursor mixture to obtain a sized precursor mixture having an average precursor particle size less than about 2 microns; placing said sized precursor mixture in a heat treatment vessel formed from platinum; heating said sized precursor mixture in said heat treatment vessel to a temperature between about 1200° C. and 2000° C. for a time sufficient to infiltrate said dopant starting material into said host lattice starting material, thereby producing a high-purity phosphor; and applying said high-purity phosphor to an anode screen of a field emission display.
Claim 13
Dependent Claim
157 words
A process for manufacturing an anode of a field emission display having a high-purity phosphor coating, said process comprising: providing a host lattice starting material and a dopant starting material; combining said host lattice starting material and said dopant starting material in a precursor mixture having an initial average particle size and substantially free of any contaminant-generating components containing a Group IA ion or a Group IIA ion; processing said precursor mixture to obtain a sized precursor mixture having an average precursor particle size less than about 2 microns; placing said sized precursor mixture in a heat treatment vessel formed from platinum; heating said sized precursor mixture in said heat treatment vessel to a temperature between about 1200° C. and 2000° C. for a time sufficient to infiltrate said dopant starting material into said host lattice starting material, thereby producing a high-purity phosphor; and applying said high-purity phosphor to an anode screen of a field emission display.
Claim 14
Dependent Claim
37 words
A process for preparing a high-purity phosphor as recited in claim 11 wherein said host lattice starting material is selected from the group consisting of silicates, aluminates, oxides, gallates, vandates, tungstates, phosphates, fluorides, oxysulfides, and mixtures thereof.
Claim 15
Dependent Claim
30 words
A process for preparing a high-purity phosphor as recited in claim 11 wherein said dopant starting material is selected from the group consisting of lanthanides, transition metals and mixtures thereof.
Claim 16
Dependent Claim
23 words
A process for preparing a high-purity phosphor as recited in claim 11 wherein said high-purity phosphor is a binary or a ternary phosphor.
Claim 17
Dependent Claim
24 words
A process for preparing a high-purity phosphor as recited in claim 11 wherein said average precursor particle size is less than about 1 micron.
Claim 18
Dependent Claim
55 words
A process for preparing a high-purity phosphor as recited in claim 11 wherein said precursor mixture is processed to obtain said sized precursor mixture by milling said precursor mixture in a reciprocating mill, thereby reducing said initial average particle size of said precursor mixture to said average precursor particle size of said sized precursor mixture.
Claim 19
Dependent Claim
196 words
A process for preparing a high-purity phosphor having utility as a luminescent in a field emission display, said process comprising: providing a host lattice starting material selected from the group consisting of silicates, aluminates, oxides, gallates, vandates, tungstates, phosphates, fluorides, oxysulfides, and mixtures thereof, and providing a dopant starting material selected from the group consisting of lanthanides, transition metals, and mixtures thereof; combining said host lattice starting material and said dopant starting material in a precursor mixture having an initial average particle size, wherein said precursor mixture consists essentially of said host lattice starting material and said dopant starting material and is substantially free of any contaminant-generating components containing a Group IA ion or a Group IIA ion; milling said precursor mixture to obtain a sized precursor mixture having an average precursor particle size less than about 1 micron; placing said sized precursor mixture in a substantially impervious heat treatment vessel formed from platinum; and heating said sized precursor mixture in said heat treatment vessel to a temperature between about 1400° C. and 1800° C. for a time sufficient to infiltrate said dopant starting material into said host lattice starting material, thereby producing a high-purity phosphor.
Claim 20
Dependent Claim
196 words
A process for preparing a high-purity phosphor having utility as a luminescent in a field emission display, said process comprising: providing a host lattice starting material selected from the group consisting of silicates, aluminates, oxides, gallates, vandates, tungstates, phosphates, fluorides, oxysulfides, and mixtures thereof, and providing a dopant starting material selected from the group consisting of lanthanides, transition metals, and mixtures thereof; combining said host lattice starting material and said dopant starting material in a precursor mixture having an initial average particle size, wherein said precursor mixture consists essentially of said host lattice starting material and said dopant starting material and is substantially free of any contaminant-generating components containing a Group IA ion or a Group IIA ion; milling said precursor mixture to obtain a sized precursor mixture having an average precursor particle size less than about 1 micron; placing said sized precursor mixture in a substantially impervious heat treatment vessel formed from platinum; and heating said sized precursor mixture in said heat treatment vessel to a temperature between about 1400° C. and 1800° C. for a time sufficient to infiltrate said dopant starting material into said host lattice starting material, thereby producing a high-purity phosphor.
Claim 21
Dependent Claim
33 words
A process for preparing a high-purity phosphor as recited in claim 17 wherein said phosphor has an average product particle size no greater than about 50% larger than said average precursor particle size.
Claim 22
Dependent Claim
136 words
A process for preparing a high-purity phosphor having utility as a luminescent in a field emission display, said process comprising: providing a host lattice starting material and a dopant starting material; combining said host lattice starting material and said dopant starting material in a precursor mixture having an initial average particle size and substantially free of any fluxes or antioxidants; processing said precursor mixture to obtain a sized precursor mixture having an average precursor particle size less than about 2 microns; placing said sized precursor mixture in a heat treatment vessel formed from platinum; and heating said sized precursor mixture in said heat treatment vessel to a temperature between about 1200° C. and 2000° C. for a time sufficient to infiltrate said dopant starting material into said host lattice starting material, thereby producing a high-purity phosphor.
Claim 23
Dependent Claim
136 words
A process for preparing a high-purity phosphor having utility as a luminescent in a field emission display, said process comprising: providing a host lattice starting material and a dopant starting material; combining said host lattice starting material and said dopant starting material in a precursor mixture having an initial average particle size and substantially free of any fluxes or antioxidants; processing said precursor mixture to obtain a sized precursor mixture having an average precursor particle size less than about 2 microns; placing said sized precursor mixture in a heat treatment vessel formed from platinum; and heating said sized precursor mixture in said heat treatment vessel to a temperature between about 1200° C. and 2000° C. for a time sufficient to infiltrate said dopant starting material into said host lattice starting material, thereby producing a high-purity phosphor.
Claim 24
Dependent Claim
148 words
A process for manufacturing an anode of a field emission display having a high-purity phosphor coating, said process comprising: providing a host lattice starting material and a dopant starting material; combining said host lattice starting material and said dopant starting material in a precursor mixture having an initial average particle size and substantially free of any fluxes or antioxidants; processing said precursor mixture to obtain a sized precursor mixture having an average precursor particle size less than about 2 microns; placing said sized precursor mixture in a heat treatment vessel formed from platinum; heating said sized precursor mixture in said heat treatment vessel to a temperature between about 1200° C. and 2000° C. for a time sufficient to infiltrate said dopant starting material into said host lattice starting material, thereby producing a high-purity phosphor; and applying said high-purity phosphor to an anode screen of a field emission display.
Claim 25
Dependent Claim
148 words
A process for manufacturing an anode of a field emission display having a high-purity phosphor coating, said process comprising: providing a host lattice starting material and a dopant starting material; combining said host lattice starting material and said dopant starting material in a precursor mixture having an initial average particle size and substantially free of any fluxes or antioxidants; processing said precursor mixture to obtain a sized precursor mixture having an average precursor particle size less than about 2 microns; placing said sized precursor mixture in a heat treatment vessel formed from platinum; heating said sized precursor mixture in said heat treatment vessel to a temperature between about 1200° C. and 2000° C. for a time sufficient to infiltrate said dopant starting material into said host lattice starting material, thereby producing a high-purity phosphor; and applying said high-purity phosphor to an anode screen of a field emission display.
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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) | 2000-02-11 | 2000-08-12 | 2001-02-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2004-02-11 | 2004-08-12 | 2005-02-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2008-02-11 | 2008-08-12 | 2009-02-11 | $7700.00 | Window Closed / Lapsed |