Discharge lamp arc tubes
US4694219A · kind A · utility
9Cited by
8References
4Claims
0Family size
Assignee
Inventor
Key dates
| Filing date | Jan 8, 1986 |
| Grant date | Sep 15, 1987 |
| Priority date | — |
| Expiry date | Jan 8, 2006 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC04B2237/765
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
An arc discharge lamp is provided using sealing compositions comprising mainly Al.sub.2 O.sub.3 --SiO.sub.2 --MgO. Preferred compositions include between 25 to 28% by weight of MgO and 13 to 21% by weight of Al.sub.2 O.sub.3 since these have lower melting points than others in the group. The sealing compositions are used to seal end closure members of alumina or cermet to ceramic arc tubes for use in discharge lamps. The compositions are selected to have linear expansion co-efficients compatible with the materials of the end closures and arc tubes. The methods described give sealing times of between 3 and 4 minutes.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.