Method of forming a partial coating on phosphor particles by coating the phosphors in a fluidize bed for a limited time and subsequently annealing to promote ionic diffusion
US5258201A · kind A · utility
Inventors
Key dates
| Filing date | Sep 23, 1992 |
| Grant date | Nov 2, 1993 |
| Priority date | — |
| Expiry date | Sep 23, 2012 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC09K11/025
- WIPO fieldBasic materials chemistry
- WIPO sectorChemistry
Abstract
A method of forming a partial protective coating on phosphor particles to improve initial power output and maintenance of fluorescent lamps made with the phosphor. The phosphor particles are fluidized in a bed and at least partially enveloped by a coating precursor material. Residence time of the phosphor particles in the fluidized bed is short so that the phosphor particles are only partially coated with the coating precursor material. The coating precursor material is reacted to form a protective coating over at least a portion of the surface of the phosphor particles. The partially-coated phosphor particles are then annealed to cause the protective coating to selectively cover at least a portion of certain sites on the surface of the phosphor particles.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.