Long-lasting phosphor, powdered long-lasting phosphor and method for manufacturing the powdered long-lasting phosphor
US6284156A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 12, 1999 |
| Grant date | Sep 4, 2001 |
| Priority date | — |
| Expiry date | Nov 12, 2019 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC09K11/7785
- WIPO fieldBasic materials chemistry
- WIPO sectorChemistry
Abstract
There is provided a long-lasting phosphor having a base crystal of akermanite crystal structure consisting of R' (where R' is one or more elements selected from the group consisting of Ca, Sr and Ba), Mg, Si, O and N and comprising Eu as an activator and one or more co-activators such as Dy. The long-lasting phosphor is produced by sintering materials including strontium nitrate to grow the base crystal of akermanite crystal structure, or by changing a solution containing constituent elements or material in the state of suspension into fine particles of liquid by atomization and thereafter heating the fine particles of liquid in a gas stream under oxidating, neutral or reducing atmosphere. The new Mohs' scale of hardness of the long-lasting phosphor is less than 1. Phosphorescence brightness of the long-lasting phosphor 2 minutes after stoppage of irradiation of illuminance of 1000 lux for 30 minutes with a white fluorescent lamp is 200 mCd/m.sup.2 or over.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.