Patent · US Expired

Method of coating a luminescent material

US6150757A · kind A · utility

6Cited by

3References

11Claims

0Family size

Assignee

U.S. Philips Corporation · US

Inventors

Cornelis Reinder Ronda · Aachen, DE
Volker Weiler · Aachen, DE
Annette Johnen · Eschweiler, DE
Johannes A. F. Peek · Auxerre, FR
Wilhelmus M. P. Van Kemenade · Maarheeze, NL

Key dates

Filing date	Jun 19, 1998
Grant date	Nov 21, 2000
Priority date	—
Expiry date	Jun 19, 2018

Classification

Technology area (CPC Y)Emerging Cross-Sectional Technologies
CPC primaryY10T428/2958
WIPO fieldElectrical machinery, apparatus, energy
WIPO sectorElectrical engineering

Abstract

A luminescent material coated with a crystalline layer of a metal oxide M.sub.2 O.sub.3 wherein a metal M is chosen from the group formed by Y and Al is shown. According to this method the luminescent material is first introduced into a solution of a salt of the metal M, then a compound of the metal M is deposited on the luminescent material through homogeneous precipitation, and subsequently the luminescent material is separated from the solution, dried, and heated. It is achieved thereby that the luminescent material will absorb mercury to a low degree only, and that accordingly the color point of a low-pressure mercury discharge lamp whose luminescent layer comprises a luminescent material coated in accordance with the invention only shows a small shift as the lamp ages.

Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.