"Lighting accounts for 30% of all electricity usage in offices, homes, transport systems and retail. It is expected to be revolutionised by the widespread introduction of LED solid state technology. However, LED technology has some major problems to overcome on the delivered efficiency of multi-LED lights, cost, and the quality of the light colour produced.HERCULES will produce solutions for LED lighting for a range of applications. It will build on a successfully demonstrated concept that combines the light from different LED sources to produce near perfect colour rendition at colour temperatures as low as 2500K. HERCULES will provide the normal benefits of LED lighting – high electrical energy to light conversion efficiency (reducing energy consumption), instant start-up and efficient dimmability, but will also allow tuneable colour rendering for applications such as food retailing.It is essential that light sources produce high quality colour rendition, which has proved critical to the health and productivity of workers. High efficiency LEDs have very poor colour rendering and current approaches use multiple phosphors on each LED to generate a poor typically “blue rich” approximation to natural light. These phosphors can seriously reduce the efficiency of the LED, so more LEDs are required to achieve the light ouput. In a compact light source this has the effect of increasing the temperature of the LEDs, which has a very negative feedback as their efficiency decreases rapidly with temperature. The HERCULES solution will overcome this serious limitation.The key developments in this project will be:• Characterisation and selection of suitable high efficiency LEDs• Novel electronic driver design• Optical design for several form factors, especially to de-image LEDs• Low cost injection moulding tool making technique for optical finish• Precision injection moulding of optical elements• Novel luminaire design for indoor/outdoor/specialist applications"