Future developments in lamps

After reviewing the principal ways in which light is produced, and some of the limitations on lamp performance imposed by the basic laws of nature, the prospects for new developments in existing types of lamp are considered, including short-term predictions, and longer-term speculations. Some more exotic possibilities are then discussed which may lead to completely new ways of producing light in the future. Only sources producing incoherent light for general illumination are considered, displays, lasers and other special purpose sources being mentioned only incidentally. Likewise, matters relating to fittings and control equipment receive only passing attention. Emphasis is on developments leading to higher efficacy, although with some consideration to other aspects of performance such as colour properties, stability and life. It is suggested that sources utilising non-thermal electronic processes hold the greater promise for really substantial gains in performance, but some fairly basic discoveries will be needed before these can be realised in practically useful lamps.