http://rdf.ncbi.nlm.nih.gov/pubchem/patent/GB-1102825-A
Outgoing Links
| Predicate | Object |
|---|---|
| assignee | http://rdf.ncbi.nlm.nih.gov/pubchem/patentassignee/MD5_1e70c0aeade92d7571d955d3b90ea06e |
| classificationCPCInventive | http://rdf.ncbi.nlm.nih.gov/pubchem/patentcpc/C09K11-7747 http://rdf.ncbi.nlm.nih.gov/pubchem/patentcpc/C09K11-7744 |
| classificationIPCInventive | http://rdf.ncbi.nlm.nih.gov/pubchem/patentipc/C09K11-77 |
| filingDate | 1966-05-24-04:00^^<http://www.w3.org/2001/XMLSchema#date> |
| publicationDate | 1968-02-14-04:00^^<http://www.w3.org/2001/XMLSchema#date> |
| publicationNumber | GB-1102825-A |
| titleOfInvention | Luminescent compositions |
| abstract | A terbium activated thorium oxyfluoride luminescent material is of a single-phase fluorite crystal structure, the proportions of Th and Tb cations and O and F anions being such that the maximum solubilities of terbium trifluoride and thorium tetrafluoride in thorium dioxide are not exceeded. Starting materials of thorium and terbium oxides and fluorides may be mixed and heated to at least 900 DEG C., preferably 1600 DEG C. in an inert atmosphere up to 20 atmospheres pressure for instance. The maximum solubility of TbF3 in ThO2 is given by Tb/(Th + Tb) = 0.05, the exact value varying with temperature and the F/Tb ratio, the single phase fluorite structure not being obtained above this, although new luminescent compositions can be obtained with higher proportions of Tb wherein a mixture occurs of the fluorite crystal structure diluted with compositions of other crystal structures; the practical lower limit is 0.0005. The practical range of F/Tb is 0.5 to 100, preferably 1 to 40 while for the ratio F/(Th + Tb), the lower limit is 0.01, preferably 0.025, the upper limit being approximately 0.6. Optimum values are 2.5 to 3.5 for F/Tb and 0.01 to 0.05, particularly 0.02, for Tb/(Th + Tb). Examples describe a number of variations in the preparations of a large number of materials and the relative luminescent efficiencies of the final products over a range of wavelengths 2630 to 6000 <\>rA. The phosphors can be used in X-ray intensifying screens, fluorescent lights e.g. low-pressure mercury lamps, and colour TV tubes. |
| isCitedBy | http://rdf.ncbi.nlm.nih.gov/pubchem/patent/WO-2012110660-A1 |
| priorityDate | 1965-05-24-04:00^^<http://www.w3.org/2001/XMLSchema#date> |
| type | http://data.epo.org/linked-data/def/patent/Publication |
Incoming Links
Total number of triples: 24.