Decentralized Nonimaging Micro-optical Concentrator

摘要

A novel non-imaging micro-concentrator concept and its development in Sandia National Lab's microsystems-enabled photovoltaics (MEPV) program are described in this paper. Key notions of the compact 2-element optical concentrator are toroidal lens surfaces that decentralize the focused beam and a reflective cone structure that enhances light collection and illumination onto micro-scale solar cells (e.g., ～100's microns in diameter). The optical configuration therefore provides a low-intensity, hot-spot-free illumination pattern on the receiver while achieving a concentration-acceptance angle product (CAP) over 1. Designs taking into account practical factors (such as fabrication capabilities, misalignments) achieve a 400X geometric concentration with a ±2.4° (90% of peak) acceptance angle (CAP = 0.84) and a 600X geometric concentration with a ±2° acceptance angle (CAP = 0.85), allowing low cost, mass production using injection molding. Development and experimental evaluation of a baseline prototype module is also described.