Process for producing a terbium-activated gadolinium oxysulfide X-ray phosphor wherein the green/blue emission ratio is controlled
US5096614A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 20, 1989 |
| Grant date | Mar 17, 1992 |
| Priority date | — |
| Expiry date | Mar 20, 2009 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC09K11/7771
- WIPO fieldBasic materials chemistry
- WIPO sectorChemistry
Abstract
A process is disclosed for adjusting the green/blue emission ratio in a terbium-activated gadolinium oxysulfide x-ray phosphor, which comprises forming a uniform mixture of gadolinium oxide, sulfur, sodium carbonate, sodium hydrogen phosphate, and terbium oxide, firing the mixture in a closed vessel in an air atmosphere to form the phosphor, washing the phosphor with deionized water to remove essentially all of any water soluble impurities which are present, and deagglomerating and annealing the phosphor in air at a temperature of from about 400.degree. C. to about 600.degree. C. for a sufficient time to form the phosphor. The terbium concentration and firing temperature and firing time are controlled to attain the desired green/blue emission ratio. As the terbium concentration increases, the ratio increases. As the firing temperature and time increase, the ratio decreases.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.