Monolithic seal for a sapphire metal halide lamp
US6873108B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Sep 14, 2001 |
| Grant date | Mar 29, 2005 |
| Priority date | — |
| Expiry date | Mar 25, 2022 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01J61/363
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A ceramic metal halide discharge lamp may be made having a monolithic seal between a sapphire arc tube and a polycrystalline alumina cap. The lamp is made by providing an arc tube of fully dense sapphire and providing a cap made of unsintered compressed polycrystalline alumina doped with magnesium oxide and yttrium oxide. The cap is presintered to remove binder material at a low temperature. The presintered cap is placed on an end of the arc tube to form a close interface. The presintered cap and arc tube are then heated to until the cap is fully sintered onto the arc tube and the sapphire tube grows into the cap. A monolithic seal is formed along the interface as the sapphire grows into the polycrystalline alumina.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.