The Effect of an Auxiliary External Electrode on Low-pressure Xenon Pulsed Discharge

The fluorescent lamps are widely used for general lighting because of their high efficacy, long life and so forth. Mercury which is used in fluorescent lamps for general lighting has a possibility to cause environmental problems. The author´s group has been developing fluorescent lamps which contain only rare gases without mercury. The wavelength of the xenon resonance line is the longest in the rare-gas resonance lines, so that the Stokes-loss becomes smaller than the other rare-gases´ cases. Therefore the authors have investigated pulsed xenon fluorescent lamps. However luminous flux of xenon fluorescent lamps was not large enough. The authors have been making efforts to improve luminous flux of the xenon lamp by expanding positive column. By setting an auxiliary external electrode on the outside wall of the lamp, positive column expands and luminous flux increases. However luminous efficacy decreases because power consumption through the external electrode is too large. So by using resistor, the current flowing through the external electrode is suppressed and power consumption decreased. Consequently higher luminous efficacy up to 100 lm/W with high luminance 6894 cd/m² is achieved