Firing and milling method for producing a manganese activated zinc silicate phosphor
US4956202A · kind A · utility
Assignees
Inventors
Key dates
| Filing date | Oct 27, 1989 |
| Grant date | Sep 11, 1990 |
| Priority date | — |
| Expiry date | Oct 27, 2009 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC09K11/595
- WIPO fieldBasic materials chemistry
- WIPO sectorChemistry
Abstract
A method for producing manganese activated zinc silicate phosphor wherein the individual phosphor particles are surrounded with a non-particulate, conformal aluminum oxide coating is disclosed. The method comprises dry blending a mixture of components consisting essentially of zinc oxide, silicic acid, a source of manganese, ammonium chloride, ammonium fluoride, tungstic oxide, and silica, wherein the Zn+Mn/Si mole ratio is from about 1.95 to about 2.02, wherein the silica is colloidal and has a surface area of from about 50 to about 410 m.sup.2 per gram, and wherein the colloidal silica makes up from about 0.01% to about 1.0% by weight of the mixture; firing the resulting dry blend of components in a nitrogen atmosphere at a temperature of from about 1200.degree. C. to about 1300.degree. C. for a sufficient time to produce the phosphor; milling the resulting phosphor for a period of time of from about 60 minutes to about 120 minutes; firing the resulting milled phosphor in air at a temperature of from about 1175.degree. C. to about 1275.degree. C. for a sufficient time to diffuse the tungsten and manganese to the surfaces of the phosphor particles; applying a non-particulate, conf…
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