Low‐Cost Volumetric 3D Printing of High‐Precision Miniature Lenses in Seconds

Abstract

3D printing is a promising method for the generation of complex‐shaped optical components. However, the printing efficiency, form accuracy, and surface smoothness are still challenging, especially for the printing of optical components. In this study, by synergizing the volumetric projection stereolithography, meniscus equilibrium effect, and iterative learning scheme, a low‐cost volumetric 3D printing method is developed for the ultra‐fast and high‐precision fabrication of miniature lenses with sub‐nanometric roughness. By including the covered liquid film as a part of the printed lens in the iterative learning, a low form error at the micrometer scale is achieved for the printed lens without any prior knowledge of the 3D printing process. As a demonstration, a sphere lens at the millimeter scale is directly printed in 2 s, achieving a peak‐to‐valley profile error of less than 5 µm, a sub‐nanometric roughness of rms = 0.614 nm, and an imaging resolution of 203.2 lp mm−1. It suggests that besides fast prototyping, the developed 3D printing strategy is suitable for the massive production of precise lenses.

Ultra-fast 3D printing of assembly—free complex optics with sub-nanometer surface quality at mesoscale

“…Energy modulation using the volumetric method has a definite advantage in printing speed. However, the single-angle volumetric energy modulation [21] necessitates a support structure to house the printed lens. In our work, multi-angle projection (figure S7) in a high-viscosity resin for light dose delivery can generate the target body simultaneously after reaching the energy threshold, as shown in figure S8.…”

“…However, although CLIP dramatically increased the printing speed, the surface quality of optical lenses obtained is still constrained by the step effect. Therefore, the methods of mechanical oscillation assistance [10], grayscale polymerization method [12], post-coating [20], and meniscus equilibrium post-curing method [11,[21][22][23][24] have been developed for reducing the roughness of the surface down to the nanometer level. Among them, meniscus equilibrium post-curing method which requires no extra-facility is a convenient and effective way to improve the surface quality.…”

Random Silica-Glass Microlens Arrays Based on the Molding Technology of Photocurable Nanocomposites

“…In recent years, high-energy lasers have attracted much attention for their wide range of applications in laser illumination, − laser detection, etc. − Lasers exhibit a Gaussian distribution and strong coherence, requiring beam modulation for applications in photolithography, − laser projection, high-performance illumination, etc. − The realization of high-energy laser beam modulation often relies on extremely high threshold materials, which are conventionally used by silica glass. Among a bunch of approaches to beam homogenization, − microlens arrays (MLAs), due to their superior energy utilization, high flexible integration, and high homogeneity, are one of the most commonly used homogenizers. − However, due to the periodicity of the MLAs, interference between beamlets happens, and their related interference fringes appear in the obtained homogenized spots, seriously impacting the uniformity of the spots. To break the coherence between small beams, a continuous profile MLA with random aperture size and arrangement of sub-lenses is proposed, which is generally called random microlens arrays (rMLAs).…”

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

“…Individual lenses or lenslet arrays, manufactured using SLA techniques, have been so far applied to image chrome lithography resolution targets [15,16,23] or by analysing the shape of a transmitted laser beam [20]. Although these tests are integral for quality benchmarks of in-house lens fabrication, the application and full performance evaluation of 3D printed lenses in biological or biomedical imaging questions has so far been neglected.…”

“…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 [17,18]. Custom techniques have been developed previously to improve the capabilities of low-cost optical printing, such as iterative learning printing algorithms which adjust grayscale pixel values throughout the print, or image pattern defocusing to smooth the lateral pixel gaps, both of which minimise the occurring staircase effect [19,20], yet still include a coating post-process step. Aside from coating techniques, liquid immersion lens moulding can produce lens geometries theoretically invariant of diameter or complexity and without the need for post-processing [21,22].…”