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US 7,678,293 B2Granted
Coated fluorescent substance, light emitting device comprising said substance and a method for producing said substance
AssigneesOSRAM GmbH, OSRAM Opto Semiconductors GmbH
InventorsBert Braune, Torsten Fries, Rainer Schirmer, Martin Zachau, Franz Zwaschka
Life of this patent
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Abstract
A coated phosphor, formed by a powder of individual grains of a phosphor as base material, the grains being coated with a coating material. The layer comprises a plurality of individual layers and is particulate in form, the individual primary particles of the layer being at least 5 nm in size. The mean layer thickness is at least 20 nm.
Claims17
A coated phosphor, comprising:
- a powder of individual grains of a phosphor as base material, the grains being coated with a non-conductive external layer of a coating material, the phosphor being excitable by ultraviolet or visible radiation,
- wherein the non-conductive external layer has an inhomogeneous thickness with a mean layer thickness of at least 20 nm and comprises a plurality of individual layers, each of the individual layers comprising the coating material and being particulate in form, the individual primary particles of the non-conductive external layer being at least 5 nm in size, and at least some of the individual primary particles of the coating material of the non-conductive external layer are lumped together to form aggregates and agglomerates thereby forming the inhomogeneous thickness of the non-conductive external layer.
Dependencies are inferred from the claim text.