Double-enveloped lamp having a shield surrounding a light-source capsule within a thick-walled outer envelope
US4888517A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 5, 1989 |
| Grant date | Dec 19, 1989 |
| Priority date | — |
| Expiry date | May 5, 2009 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01J61/34
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A double-enveloped lamp having a shield surrounding a light-source capsule within a thick-walled outer envelope so that the lamp may be safely operated without necessity of a protective fixture. In the rare event of a burst of the light-source capsule, the shield absorbs and dissipates a portion of the burst energy sufficient to permit the thick-walled outer envelope to remain intact and contain shards and other internal parts within the lamp. In alternate embodiments, the shield may be reinforced, such as with a wire mesh, or the outer envelope may be reinforced, such as with a polymer coating, or both. A thin-walled capsule may be employed in combination with a shield and thick outer envelope. A lamp in accordance with the invention provides the unexpected benefits of improved luminous efficacy and better color rendering characteristics, since the presence of an optimally positioned shield causes the operation of the light-source capsule to be more nearly isothermal.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.