Self-assembled photocurable polymer biconvex microlens array based on double-faced discontinuous hydrophobic surface

Biconvex microlens arrays (MLAs) are key parts in optical systems. In this work, a facile method was developed for the fabrication of biconvex MLAs on ultrathin glass substrates, in which both sides were modified with microholes patterned hydrophobic layers. The difference of the hydrophobicity inside and outside the microholes pattern were very large. The photocurable polymer formed droplets array on the discontinuous hydrophobic layer self-assembly, and polymeric biconvex MLAs were obtained after UV curing. Each polymeric dome formed on front and back sides was concentric and preserved the same size. The as-obtained biconvex MLAs showed an average diameter of 297 μm, a focal length of 669 μm, a numerical aperture (NA) of 0.21, and a maximum resolution of 45.3 lp/mm. Compared to plano-convex MLAs using the same materials with the same size, which exhibits the maximum resolution of 16 lp/mm, the biconvex MLAs displayed highly improved optical resolution. In sum, the advantages of the proposed method in terms of simple fabrication, good optical performances and high consistency in large areas make it promising for use in 3D displays, image processing, fiber coupling, optical data storage, light extraction, and biomedical processing.