Abstract

Lensless imaging is a recently developed technique that achieves ultra-compact and low-cost cameras by replacing the lens module with a thin film mask. In this paper, we propose a method to design and fabricate custom phase-masks to create deterministic point spread functions (PSFs) for lensless imaging. Phase-masks are designed using our wave-optics-based simulation algorithm and are fabricated in single-shot via gray-scale maskless lithography technique. Using this method, we can design and fabricate phase-masks with various surface profiles, resulting PSFs and focal lengths, and have validated that the fabricated masks match the designed profiles. We also show that lensless cameras using our custom phase-masks can effectively obtain images in compact form factor. Our technique allows for a fast and efficient process that can be applied to the fab-level fabrication of lensless cameras for commercialization. We report on the design method of the phase-masks, the fabrication methods, and the resulting images and also discuss the potential applications of our ultra-thin lensless camera.