The European project, HILED (www.hi-led.eu/), is probing the effects of light on people’s health and circadian rhythms, the growth rate of plants, and the preservation and perception of paintings. HI-LED is developing new light engines by optimizing configurations of Light Emitting Diodes (LEDs) and by combining LEDs with Organic Light Emitting Diodes (OLEDs), and creating dynamically tunable lamps that can fit many different applications. Green OLEDs have been developed which compensate for the low efficiency of green LEDs and are being combined with LEDs in other wavebands to create new light engines for use in museum and human-centric applications. For human health and performance, the HI-LED project is considering the effect of different light spectra on the suppression of melatonin (the “sleepiness” hormone), which is a measure for quantifying stimulation of the non-visual pathway, which originates in a special class of melanopsin-containing retinal cells only discovered in 2002. The work has also been performed analyzing the potential degradation of artwork by different light spectra. In addition, an LED light engine has been developed to look at the effects of different light spectra exposure on the growth of horticultural products like tomatoes and their effects on leaf area, orientation, plant length as well as photosynthesis and chlorophyll content.
Project partners: IREC, IRTA, LPI, Fraunhofer, Wageningen UR, Hortilux Schreder, Newcastle University, ARCH Technology, University of Pannonia.