CoeLux's simulated natural daylight system.
CoeLux CoeLux's simulated natural daylight system.

Early electric lamps most closely approximated firelight. Seen from a distance, the warm, pinpoint glow of the first incandescent might easily have been confused with its candle or gas lamp antecedents. Over time, however, lighting manufacturers have aspired to mimic daylight instead. This goal has proven to be a significant challenge, given the spectral complexity, variability, and depth characteristics of natural sunlight and the visual effects created by the atmosphere through which it passes.

Undaunted by the task, Italian start-up CoeLux has achieved compelling results with its new daylight simulation system. The technology emulates daylight with LEDs that render a color spectrum similar to that of daylight; nanostructured materials that convey the Rayleigh process of atmospheric light-scattering; and a multilayered system that provides the visual depth of the sky dome.

Just as daylight is highly variable, so is CoeLux. The system can recreate the light qualities of early morning, noon, and evening illumination. It can also simulate the appearance of sunlight in different latitudes, from the tropics to northern Europe. Paolo Di Trapani, founder of CoeLux and an associate professor of optics and experimental physics at the University of Insubria, in Italy, told Photonics in April that the system allows users to “experience sunny skies anytime, anywhere.”

CoeLux is not yet commercially available and it has significant design requirements—calling for a space one-meter deep above the ceiling for installation. The system also suggests provocative implications for interior environments. On the one hand, light- and view-challenged spaces can now deliver a vastly improved experience for inhabitants. On the other hand, CoeLux technology could reduce the need for architects to design buildings that are responsive to daylight and that encourage connections with the outdoors. Nevertheless, a slice of tropical sky would be a welcome prospect for anyone suffering through another interminable winter season.
