Linear Fresnel Lens for a Solar Cell with above 85% Focal Efficiency

We designed a linear Fresnel lens (LFL) for harvesting solar energy. The optimized LFL was fabricated with dimensions of 100 (W) × 100 (H) × 5(T) mm3, a focal length of 100 mm, and a fixed pitch size of 500 µm. The maximum focal efficiency is approximately 91%, and the half width at half maximum (HWHM) value of the focus size is approximately 130 µm. We also investigated the robustness of the LFL to changes in the incident angle, draft angle, and detection position. Simulations revealed a focal efficiency above 85% with an incident angle up to 1°, a draft angle up to 10°, and a detection position up to ±10 mm. We fabricated the LFL by using an injection molding process. The fabricated lens had a maximum focal efficiency of approximately 88% and a full width at half max (FWHM) of about 2.5 mm.