Detailed investigation on the neon-xenon mixture as filling gas for mercury-free fluorescent lamps

Summary form only given. The conventional fluorescent lamp is a low-pressure mercury discharge device with a phosphor coating that converts ultraviolet light into visible light. Since mercury is toxic, it represents an environmental hazard and suggests a need for mercury-free light sources. Many years ago, several investigations were carried out in an endeavour to use inert gases as a substitute for mercury. Most recent studies of neon-xenon mixtures showed that a significant fraction of the input power delivered to the plasma can be converted into UV radiation. Nowadays, this mixture is most frequently used in plasma displays. While the role of neon is to decrease the operating voltage, the xenon is the active source of UV photons. Herein we report experimental investigations of a neon-xenon plasma in a cylindrical axially homogenous positive column at low pressure. The set-up of this experiment consists of three principal devices: the discharge tubes with special design, the spectroscopic detection tools with data acquisition devices and a shelling device. The tubes are made of conventional glass coated with an ordinary phosphor layer. Every tube is equipped with a pair of hollow electrodes and a pumping port. This port is connected both to the shelling device and to a vacuum ultraviolet spectrometer through an MgF/sub 2/ window and permits the evacuation and the filling of the discharge vessel as well as the performance of spectroscopic diagnostics of the glow discharge in the VUV wavelength region. End-on and side-on spectroscopic analysis of both the positive column and the near by cathode region can be performed. The main results are obtained by optimizing the xenon VUV radiation. Neon used as the primary gas, has been mixed with a suitable amount of xenon which emits mainly the VUV resonance radiation at 146.96nm and 129.56nm.