Fabrication of polydimethylsiloxane microlens array on spherical surface using multi-replication process
Journal
Journal of Micromechanics and Microengineering
Journal Volume
24
Journal Issue
1
Date Issued
2014
Author(s)
Cherng, Y.-S.
Abstract
In comparison to traditional planar optical devices, compound-eye structured optical elements can reduce the number of components and their volume when being applied to wide-field imaging and sensing systems. However, the fabrication process for microstructures on a curvilinear surface has many difficulties since traditional fabrication techniques are planar. In this paper, we present a cost-effective method to fabricate microlenses on a spherical surface. Microlenses, of which the fill factor was about 78%, were formed using the thermal reflow technique, followed by multiple replication processes to transfer the microlenses from the planar substrate onto a spherical surface. We produced a curved mold with concave microlenses, and it allowed this method to be replicable. A polydimethylsiloxane elastomer was employed as the material for both the microlenses and the mold. The radius of curvature of the spherical surface was approximately 6.1 mm. The variation of the microlenses was analyzed, demonstrating high uniformity. The imaging performance of the microlenses is also presented. The curved microlens arrays were combined with image sensors, and sub-images of objects at various distances are shown. The experimental results demonstrate a high potential for curved microlens arrays being applied to compact mobile camera lenses. © 2014 IOP Publishing Ltd.
Subjects
microlenses; mold replication; spherical surface
Other Subjects
Concave micro-lenses; Cost-effective methods; Curvilinear surfaces; Fabrication technique; Number of components; Planar optical devices; Polydimethylsiloxane elastomers; Spherical surface; Fabrication; Microlenses; Microoptics; Molds; Optical instrument lenses; Sensors; Silicones; Spheres; Surfaces
Type
journal article