Method of coating a luminescent material
US5811154A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 8, 1995 |
| Grant date | Sep 22, 1998 |
| Priority date | — |
| Expiry date | Aug 8, 2015 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01J61/44
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
The invention relates to a method of coating a luminescent material with a 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. The invention also relates to a coated luminescent material and to a low-pressure mercury discharge lamp. According to the invention, 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.