A bio-inspired hemispherical lens based on reflecting superposition compound eye optics

This paper presents the design and fabrication of a 3-dimensional (3-D), hemispherical lens based on reflecting superposition compound eye (RSCE) optics. The configuration of our hemispherical lens, similar to that of natural RSCEs, consists of a large-area array of reflective, high aspect-ratio, micro-square-tubes fabricated on a transparent, flexible and hemispherical polydimethylsiloxane (PDMS) membrane via a peeling micro-printing process. The dimensions of the micro-square-tubes are on the order of tens of microns. Unlike ordinary lenses, our RSCE device focuses light based on reflection rather than refraction. The hemispherical RSCE lens was able to focus a collimated and a non-collimated light source, respectively, with a focal length of 1.5 cm. The imaging performance was consistent with theoretic prediction based on the geometric optics model and ray-tracing technique. The device also achieved a wide field of view (FOV) of up to 100°.