Multi-LED light source for hyperspectral imaging

We investigate a novel light source design for efficient collection of UV light from multiple LEDs. The design is based on a truncated cone with a large circular lid incorporating LEDs on one side, and a small circular exit aperture (diameter of 9 mm) on the other side. The exit aperture size allows a simple coupling with secondary optics of a microscope for hyperspectral imaging that requires a wide spectrum of frequencies of illuminating light. The light collection efficiency was optimized with respect to cone length and diameter of the LED lid. In all simulations, we use a highly UV-reflecting aluminum coating on the inner surfaces of the cone. The influence of the LED positions on the cone efficiency is determined by varying the LED distance from the central axis as well as the interLED distance. We found the maximum efficiency of the cone is realized for LEDs positioned at the center, and the shorter is the inter-LED distance, the better is the performance of the light source.