Optical design and simulation of a compact multi-aperture camera based on a freeform microlens array

A novel freeform microlens array was designed for a multi-aperture camera to achieve a thin and compact system. A 3×3 microlens array has a field of view (FOV) of 24°×24°, with a thickness of only 2 mm. Optical freeform surface is used to steer the incident rays so that the principal axis of each channel is perpendicular to the surface of imaging sensor. To achieve a small sampling angle with the large FOV, the partial images of each adjacent pair of microlens are braided. The structure and principle of compact multi-aperture camera were analyzed, and the freeform microlens array was designed and simulated in details. The simulated partial images were reconstructed into one whole image with higher resolution, which proves the validity of the proposed design.