Protective metal silicate coating for a metal halide arc discharge lamp
US5394057A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 7, 1992 |
| Grant date | Feb 28, 1995 |
| Priority date | — |
| Expiry date | Aug 7, 2012 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01J61/827
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
An arc tube of fused silica for a metal halide arc discharge lamp including a fill for the arc tube comprised of a sodium halide, at least one additional metal halide, and an inert starting gas, the arc tube including a tube of fused silica having an inner wall defining an arc chamber, the inner wall of the tube having provided thereon a metal silicate coating which is vitreous and light-transmissive, and which is comprised of a silicate of at least one metal selected from the group consisting essentially of scandium, yttrium, and a rare earth element, and preferably which is the same metal as that of the at least one additional metal halide. Protection of the fused silica arc tube with the metal silicate coating reduces loss of the metallic portion of the fill by diffusion or reaction and corresponding buildup of free halogen in the arc tube.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.