Fabrication of microlenses by direct photo-induced crosslinking polymerization

Growing interest in the manufacture of microlenses results from their standard use as optical components with current applications in the telecommunication industry. A number of techniques were developed by using various materials and processes. One approach involved the ability of self-processing photopolymers to generate microlens arrays. Spatially controlled illumination of a photosensitive layer induced an inhomogeneous photopolymerization involving formation of 3-D polymer network, mass-transport process of reactive species and bending of the surface resulting from a gradient of surface free energy. The imaging process that generated as a relief in the photopolymer layer, exhibited a completely self-processing character without any chemical post-treatment. The lens arrays displayed diameters ranging from less than 100 mm to 1mm and focal lengths from 100 mm to a few millimeters, depending on photonic, optical and physico-chemical parameters. # 2000 Elsevier Science B.V. All rights reserved.