Technology usually evolves unevenly, and our cognitive understanding of innovations usually lags their development by years, decades, or generations - for instance, we still measure motor output by horsepower, and light output in candlepower. In the quest for the ideal spectrum for a general LED light source, efforts to date have tended to attempt to replicate either the now superceded technology, incandescent, or sunlight. This backward-looking frame of reference has given rise to a certain bias, or preference, for “smooth” vs “spiky” spectra, trying to match smooth black body curves or relatively smooth averaged “daylight“ spectra. Although solid state lighting is a mature technology, development continues apace as we discover more and more ways to make light better- in efficiency, in spectral design, in its ability to deliver circadian stimulus. We now have far more variety and different levels of quality available than ever before, and can engineer seemingly endless spectra, spiky or smooth. Which is best? In considering the effects of light on health and circadian processes, manufacturers practically must rely upon experts in biology and neuroscience to provide appropriate guidelines, and must deliver products that are highly consistent as well as economically feasible. While “full” or “smooth” spectra may be most useful for general interior lighting in most applications, narrowband light sources can offer many different benefits: discreet circadian stimulus, germicidal properties, horticultural applications, and dramatically improved efficiency offer the common blue-pumped packaged phosphor design, while delivering acceptable color rendering. This talk looks at different approaches to spectral design and examines the metrics behind them.

Total AIA CEU Credits: 1.5 (must attend all three Lighting Quality Metrics sessions)