The main scientific and technological objective of our proposal therefore is the system integration of the optimised LE with near perfect colour rendition in an intelligent luminaire with high lumen output, specific illumination beam profiles and shapes and with extremely low power consumption. A major achievement will be that the luminaire will have superb colour quality based on the improved light engine that will require a reduced number of LEDs, with optimised light-collection efficiency and near-perfect colour rendering, reduced energy consumption and intelligent driving electronics. The optimised intelligent luminaire system will demonstrate the capability of this technology for a much larger range of applications than the previous HD-LED technology.
The key developments required from the research in the HERCULES project will be:
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Novel, high efficiency Light Engines with better than 100lm/W efficacy. LEDs are available from several sources and each has different characteristics of size, colour spectrum, efficacy, operating voltage, predicted lifetime, and cost. The LE will have an efficacy greater than 100lm/W and the optimum white-red LED combinations will be selected for the criteria of technical performance, cost, and flexibility to accommodate the latest improvements in technology. Multi-chip LED assemblies will be also explored.
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Development of a novel, controllable electronic driver design for the LE for full visible spectrum colour rendering, as well as overall intelligent dimmable light output. The driver will use feedback from integrated sensors (colour, human presence, ambient light level etc.) and control the behaviour of multiple LEDs with respect to their combined wavelength and power level output for intelligent, application specific illumination. It will turn the lights off when no-one is present as there is absolutely no point in efficiently lighting empty rooms, and dim the lights down if there's enough light from other sources (e.g. natural light from the windows).
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Optical system solutions for directional and wide angle lighting applications, for both compact and strip sources. In addition to supporting the proposed LE for high collection efficiency (>85%) and uniform distribution over the illuminated area, the optics will need to provide diffusion of the LED sources (LED obscuration).
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An advanced thermal management solution to allow the most compact and cost effective thermal mounting for the LE system that will maximise efficiency and minimise LED junction temperature. The solution will necessitate sufficient heat spreaders that carry the LED(s) and the driver electronics as well as respective packaging technologies for proper heat flow interfaces that fulfil stability requirements in minimised geometries and thus high heat densities and temperature gradients.
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The luminaire material technology that must accommodate the LE, the electrical driver and the thermal management solution. To achieve a cost-effective solution, the latest technology in moulded polymers will be required to provide resilient structures. This will allow fabrication of low cost precision injection moulding optical elements, and surface coatings to provide environmental protection or in some applications, hygienic surfaces.
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Novel luminaire for indoor/specialist applications. A cost-effective system integration solution will be sought for a demonstrator of an Ultra High Efficiency dimmable compact light source with tuneable colour temperature (2500-6500K range) for illumination of domestic and office environments and an Ultra High Efficiency extended light source with full colour rendering (Ra >95) and red enhancement (R9>95), with low IR and UV for hospital wards, supermarkets and other medical and retail applications.
