Investigation of a moly-oxide electrodeless discharge for lighting applications

Summary form only given. Due to the hazardous material designation of spent fluorescent bulbs on board naval vessels, the Naval Research Laboratory has been investigating alternative lighting concepts which are free of mercury. The ideal goal is an efficient, large volume source, which provides white light directly without the use of a phosphor coating. Experiments with a /spl mu/wave plasma reactor normally used for diamond growth at /spl sim/40 Torr revealed that a combination of O/sub 2/, N/sub 2/, and a heated molybdenum puck led to intense plasma emission in the visible domain. As the reactor was not designed for lighting studies, we have been investigating the process in glass tubes with a re-entry geometry and RF driven coils. Results will be presented on the initial discovery, the role of moly-oxide in surface evaporation, and the favorable emission spectrum of atomic molybdenum for visible light. Initial studies of the RF system, including coil design, measured electron density, B-dot measurements, E-to-H transitions, and spectroscopic analysis of various compositions will also be discussed. Finally, the essential problem of a recycling process for the moly emitters from the glass walls back to the moderate pressure plasma using chlorine will be addressed.