Ultra-compact 3D-printed wide-angle cameras realized by multi-aperture freeform optical design

Simultaneous realization of ultra-large field of view (FOV), large lateral image size, and a small form factor is one of the challenges in imaging lens design and fabrication. All combined this yields an extensive flow of information while conserving ease of integration where space is limited. Here, we present concepts, correction methods and realizations towards freeform multi-aperture wide-angle cameras fabricated by femtosecond direct laser writing (fsDLW). The 3D printing process gives us the design freedom to create 180 degrees x 360 degrees cameras with a flat form factor in the micrometer range by splitting the FOV into several apertures. Highly tilted and decentered non-rotational lens shapes as well as catadioptric elements are used in the optical design to map the FOV onto a flat surface in a Scheimpflug manner. We present methods to measure and correct freeform surfaces with up to 180 degrees surface normals by confocal measurements, and iterative fabrication via fsDLW. Finally, approaches for digital distortion correction and image stitching are demonstrated and two realizations of freeform multi-aperture wide-angle cameras are presented. (C) 2022 Optical Society of America under the terms of the OSA Open Access Publishing Agreement

Automated summary

This research introduces the concepts, correction methods, and realizations of freeform multi-aperture wide-angle cameras fabricated by femtosecond direct laser writing (fsDLW). By splitting the field of view (FOV) into multiple apertures and using special lens shapes and catadioptric elements, a flat-form factor 180 degrees x 360 degrees camera can be created in the micrometer range. The study also presents methods for measuring and correcting freeform surfaces using confocal measurements and iterative fabrication via fsDLW. Additionally, approaches for digital distortion correction and image stitching are demonstrated, and two realizations of freeform multi-aperture wide-angle cameras are presented.