Microlens arrays (MLAs) have been widely applied. Currently, the fabricati
on of MLAs involves precise machining and photolithography, which suffe
r from high equipment costs, long production times and large amount of
wastes, and they also impose significant limitations on the shape of microl
enses. Digital light processing (DLP) 3D printing technology offers advant
ages such as low cost, shorter production time and being more environme
ntally friendly. However, the surface roughness of MLAs produced by DLP
3D printing technology is difficult to meet the requirements of optical co

mponents due to stair effect.
Our team employed adjustable grayscale masks in the manufacturing pro
cess. By adjusting the imaging position of the digital mask and the distanc
e between the mask and the forming platform, we create a defocus metho
d to eliminate stair effect and enabling the surface roughness of the micro
lens array to meet the requirements of optical components. Compared to
traditional processes, our technology can achieve MLA shapes that were p
reviously unattainable. In addition to the aforementioned manufacturing
method, our team has also utilized newly developed photopolymer specifi
cally designed for optical components. The goal is to enhance the resoluti
on, numerical aperture, and size limits of the micro lens array, thereby gre
atly expanding its range of applications.
It takes 1 second to solidify the polymer, and the entire fabrication proces
s takes 15 minutes. The resulting surface roughness is below 50 nm, while
the lens resolution can reach 58.7 lp/mm, which is more than that of com
mercial MLAs (resolution ~ 55 lp/mm). The diameter of the microlens is as
small as 60 μm. It is possible for us to fabricate microlens with high numer
ical apertures (0.98), multiple focal lengths (20 μm to 200 μm), and high fil
l factor (77.98%). The MLAs in this study can be applied to image panels a
nd sensors, and their optical performance are on par with commercial cou
nterp