Low pressure mercury discharge lamp with thermostatic control of mercury vapor pressure
US5274305A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Dec 4, 1991 |
| Grant date | Dec 28, 1993 |
| Priority date | — |
| Expiry date | Dec 4, 2011 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01J61/541
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
The mercury vapor pressure in a low pressure mercury discharge lamp is thermostatically controlled. A low pressure mercury discharge lamp includes electrodes and a source of mercury vapor sealed in a lamp envelope. A heater and a thermal switching device are in thermal contact with the source of mercury vapor. The heater is energized when the source of mercury vapor is below a predetermined temperature during operation of the lamp. The heater is preferably a resistance heater electrically connected in series with one of the lamp electrodes. The thermal switching device can be a bimetal thermostatic switch. The source of mercury vapor is typically an amalgam selected to have an optimum mercury vapor pressure at the maximum operating temperature of the lamp. The heater and the thermal switching device can be located external to the lamp envelope or can be located within the lamp envelope. The lamp provides a relatively constant light output over a broad range of operating temperatures and different lamp orientations.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.