High-pressure metal halide discharge lamp with electrodes substantially free of thorium oxide
US5530317A · kind A · utility
9Cited by
5References
16Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Oct 7, 1994 |
| Grant date | Jun 25, 1996 |
| Priority date | — |
| Expiry date | Oct 7, 2014 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01J61/0737
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
The high-pressure metal halide discharge lamp has tungsten electrodes in a light-transmitting lamp vessel which is closed in a vacuumtight manner. The electrodes comprise an emitter which is distributed throughout their mass and is formed by a first oxide chosen from hafnium oxide and zirconium oxide and by a second oxide chosen from yttrium oxide, lanthanum oxide, cerium oxide and scandium oxide, and are substantially free from thorium oxide. The lamp retains its initial light output to a high degree throughout its life.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.