Shao Guangbin, Hai Rihan, Sun Cheng
Department of Mechanical Engineering Northwestern University, Evanston, IL 60208, USA; School of Mechatronics Engineering, Harbin Institute of Technology, Harbin 150001, P. R. China.
Department of Mechanical Engineering Northwestern University, Evanston, IL 60208, USA.
Adv Opt Mater. 2020 Feb 19;8(4). doi: 10.1002/adom.201901646. Epub 2019 Dec 4.
Synergizing grayscale photopolymerization and meniscus coating processes, rapid 3D printing of optical lenses is reported previously using projection microstereolithography (PμSL) process. Despite its 14 000-fold-improved printing speed over the femtosecond 3D printing process, PμSL still consumes significant amount of the fabrication time for precise recoating 5 μm thick fresh resin layers. At the reported speed of 24.54 mm h, 3D printing of the millimeter-size lenses still takes hours. To further improve the printing speed, the microcontinuous liquid interface production process is implemented to eliminate the time-consuming resin recoating step. However, the micrometer-size pores in the Teflon membrane needed for oxygen transportation are found to completely spoil the surface smoothness. The use of polydimethylsiloxane thin film possessing much refined nanoscopic porosities as the functional substitute of Teflon membrane is reported to significantly reduce the surface roughness to 13.7 nm. 3D printing of 3 mm high aspherical lens in ≈2 min at a 200-fold-improved speed at 4.85 × 10 mm h is demonstrated. The 3D printed aspherical lens has the demonstrated imaging resolution of 3.10 μm. This work represents a significant step in tackling the speed-accuracy trade-off of 3D printing process and thus enables rapid fabrication of customized optical components.
通过将灰度光聚合和弯月面涂层工艺相结合，先前已报道了使用投影微立体光刻（PμSL）工艺对光学透镜进行快速3D打印。尽管其打印速度比飞秒3D打印工艺提高了14000倍，但PμSL在精确涂覆5μm厚的新鲜树脂层时仍消耗大量制造时间。以报道的24.54mm/h的速度，毫米尺寸透镜的3D打印仍需数小时。为了进一步提高打印速度，采用了微连续液体界面生产工艺来消除耗时的树脂重新涂覆步骤。然而，发现氧气传输所需的聚四氟乙烯膜中的微米尺寸孔隙完全破坏了表面光滑度。据报道，使用具有更精细纳米孔隙率的聚二甲基硅氧烷薄膜作为聚四氟乙烯膜的功能替代品，可将表面粗糙度显著降低至13.7nm。以4.85×10mm/h的速度在约2分钟内展示了3mm高非球面透镜的3D打印，速度提高了200倍。3D打印的非球面透镜的成像分辨率为3.10μm。这项工作代表了在解决3D打印过程的速度-精度权衡方面迈出的重要一步，从而能够快速制造定制光学元件。
