Printing, Characterising, and Assessing Transparent 3D Printed Lenses for Optical Imaging

Abstract

High-quality lens production has involved subtractive manufacturing methods for centuries. These methods demand specialist equipment and expertise that often render custom high-grade glass optics inaccessible. We aimed to develop a low-cost, accessible, and reproducible method to manufacture high-quality three-dimensional (3D) printed lenses using consumer-grade technology. Various planoconvex lenses were produced using a consumer-grade 3D printer and low-cost spin coating setup, and printed lenses were compared to commercial glass counterparts. A range of mechanical and optical methods are introduced to determine the surface quality and curvature of 3D printed lenses. Amongst others, high-resolution interference reflection microscopy methods were used to reconstruct the convex surface of printed lenses and quantify their radius of curvature. The optical throughput and performance of 3D printed lenses were assessed using optical transmissivity measurements and classical beam characterisation methods. We determined that 3D printed lenses had comparable curvature and performance to commercial glass lenses. Finally, we demonstrated the application of 3D printed lenses for brightfield transmission microscopy, resolving sub-cellular structures over a 2.3 mm field-of-view. The high reproducibility and comparable performance of 3D printed lenses present great opportunities for additive manufacturing of bespoke optics for low-cost rapid prototyping and improved accessibility to high-quality optics in low-resource settings.

Low-cost 3D printed lenses for brightfield and fluorescence microscopy

“…The flat sides of all lenses have additionally a surface roughness <50 nm [ 26 ]. Additionally, the refractive index of Formlabs resin is 1.51 at 515 nm excitation [ 25 ] with Vida Rosa having shown negligible difference [ 17 ]. This should offer only minimal aberration contributions.…”

“…Stereolithography (SLA) is a low-cost 3D printing technique capable of manufacturing optical components using ultraviolet-excited photopolymerizing resins in a layer-by-layer process [ 15 , 16 , 17 ]. This stepwise process can require additional post-processing to obtain optical clarity through post-processing approaches like spin-coating or dip-coating with liquid resin, or subtractive methods such as polishing the lens surface with fine grit paper [ 18 , 19 ].…”