Microlens Array Development for Staring Forward Looking Infrared (FLIR) Sensors

Arrays of microlenses are etched onto the first surface of backside-illuminated detectors. One microlens is positioned above each detector. These devices allow 100% fill-factor to be achieved with a sparsely populated focal plane array. Also, microlenses can minimize retro-reflections by preventing illumination of mesa grooves. Other goals can also be achieved including improvements in cold shielding and in sensitivity. This proposed SBIR project involves the design of microlenses specifically to improve fill factor and reduce retro-reflections. This includes consideration of tilted microlenses and auxiliary prisms and gratings. We have already done significant work in this area and propose to continue this research. Completion of the Phase I project will result evaluation of design and fabrication techniques, and selection of feasible approaches. Performance feasibility will be demonstrated by optical analysis including scalar diffraction analysis. Manufacturing feasibility will be demonstrated by a detailed review of recommended approaches by Loral to assure compatibility with detector manufacturing methods. Phase II will include fabricating and testing non-working FPAs with microlenses arrays. Phase II would consist of fabricating functional FPAs with microlenses using non-SBIR funds and extension of the technology to uncooled focal planes for commercial exploitation.