Fabrication of bifocal curved compound eyes for large-DOF and wide-FOV imaging via femtosecond laser 3D printing

Abstract

Miniature imaging systems are pivotal in applications such as medical endoscopes, micro-robotics, virtual reality, and military reconnaissance. Nonetheless, achieving both an extended depth of field and a broad field of view in compact imaging devices remains a significant challenge. In nature, the sub-eye of trilobite compound eye exhibits a remarkable structure that focuses incoming light onto two distinct focal planes, enabling the simultaneous detection of both proximate and distant objects. Drawing inspiration from trilobite compound eye, this study introduces an innovative bioinspired design featuring a bifocal curved compound eye, offering an enhanced depth of focus and an expansive field of view. Meanwhile, the focal lengths of sub-lenses with varying orientations are meticulously designed to ensure convergence on a common imaging plane, thereby addressing the challenge of detector reception. The compound lens is manufactured through femtosecond laser 3D printing technology to achieve high-fidelity profiles that match the design. Experimental results demonstrate that the compound lens can concurrently capture images with a 90° field of view from near (<200 μm) to far (>10 cm) objects, without the need for mechanical zoom mechanisms. This breakthrough provides fresh perspectives for future applications in micro-vision technologies, including medical diagnostics and reconnaissance robotics.