Low-Pressure Gas Discharge Lamps

Abstract

This chapter provides an overview of the current technology in low-pressure discharge lamps. Because of their dominance in the market place, and production of “white” light, the major part of the chapter is devoted to fluorescent lighting. Fluorescent lamps (FL), contain mercury, a highly efficient emitter of UV radiation, which is then converted to visible radiation by a phosphor coating on the lamp. Although low-pressure sodium (LPS) lamps, which use sodium as the principal radiation source, are more efficient emitters of visible radiation than FL, they are only suitable for limited outdoor applications, due to their predominant yellow colour and hence poor colour rendering. Low pressure discharges in rare gases such as neon have been used for specialist lighting applications, but they are currently being superseded by Light Emitting Diodes (LEDs).