Some aspects of the design of incandescent GLS lamps

Abstract

The design of general lighting services (GLS) incandescent lamps must take account of many aspects, including the effect of gasfilling content and pressure, filament design, and the influence of the electrical lead-in wires and filament supports. In most instances a compromise must be made to achieve the best overall result. In general, the predominant failure mechanism is the formation and subsequent burn-out of a 'hot-spot'. Up to about 3000 hours the rate controlling process in most GLS types is tungsten evaporation, however, some evidence exists to show that for longer life lamps, and in particular low power ratings, other mechanisms such as surface and bulk diffusion of tungsten become significant and must also be taken into account in the design stages.