Ultra-compact close-up microoptical imaging system

Although several applications of machine vision and biomedical imaging ask for the close-up imaging of extended object fields, only few, mostly bulky solutions exist. We demonstrate the optical design and realization of an ultra-compact close-up imaging system with unity magnification. It uses a multi-aperture approach in order to shorten its total track length to less than 4 mm while achieving a large field of view. The system is made of a stack of several two-dimensional arrays of refractive microlenses. The potential of this setup lies in the combination of digital imaging with microoptical fabrication techniques leading to thin optical components which can be directly attached to an image sensor. Hence, these systems fit into tight spaces and they achieve a high resolution without scanning.