
29-1
29.1 Introduction
Given that electric lighting is central to modern life and consumes about 20% of global electrical power,
it is remarkable that the relatively primitive incandescent (1870s) and uorescent (1940s) technologies
are still predominant today. Light emitting diodes (LEDs) have emerged as promising lighting devices
for the future. However, LEDs are still primarily restricted to decorative, display, signage, and signaling
applications so far and have not reached the stage of massively entering the general and public illumina-
tion markets. While there has been increasing hope that LED technology may replace energy-inecient
inc ...