Spectral-Temporal LED Lighting Modules for Reproducing Daily and Seasonal Solar Circadian Rhythmicities

The daily and seasonal cycles of spectral and intensity content in the sunlight that reaches the earth's surface constitutes a natural pacemaker for activity in the terrestrial biosphere. In humans and most mammals, the evolutionary consequence of this rhythmicity is the existence of a circadian rhythm, which regulates various vital activities such as the production of hormones, mating and feeding times, and sleep according to the solar angle and the characteristics of the daylight. Thus there is a spectral-temporal relationship underpinning the rhythmicity that got built into us over the ~1,000,000 years of evolution but now has to learn to cope with the abrupt changes brought in by electric lighting ~100 years ago, To improve human quality of life and wellness, it is desired to incorporate the principal characteristics of daylight' rhythmicity in lighting. Here we describe a smart LED lighting system capable of reproducing daylight's changes in relative spectral power and circadian content with time-of- day. It achieves high-fidelity reproduction of daylight's spectral and circadian content as a function of time in a compact, relatively inexpensive and novel system that could readily be adapted for production and may offer an additional yet unstudied solutions in areas were lighting as therapy are being developed.