Metal halide discharge lamp with a quartz discharge vessel and an outer UV radiation absorbent envelope
US5854535A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 25, 1996 |
| Grant date | Dec 29, 1998 |
| Priority date | — |
| Expiry date | Jun 25, 2016 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01J61/302
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A metal halide lamp has an outer envelope (3, 23) of quartz glass which sounds a discharge vessel (2, 22) of quartz glass. The discharge vessel (2, 22) gas-tightly retains an ionizable fill which includes sodium. In order to avoid loss of sodium from the discharge vessel (2, 22) due to UV radiation impinging upon current supply wires (8, 9, 28, 29) extending from the discharge vessel (2, 22) within and into the outer envelope (3, 23), the quartz glass of the outer envelope is doped with materials absorbing UV radiation, preferably cerium aluminate and titanium oxide; the outer envelope is spaced from the discharge vessel by at most 5 mm, the sodium content in the ionizable fill is at most 0.7 mg.sup.3 of the discharge volume, and the space within the outer envelope is evacuated.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.