Refractive Microlens Fabrication by Ink-Jet Process

Microlenses made of hybrid organic-inorganic materials have been fabricated on glass substrates using a commercial drop-on-demand ink-jet printing system with a 50 m diameter nozzle driven by a piezoelectric device. After deposition the drops have been polymerized by UV light irradiation. Viscosity, solvent evaporation, drop-substrate wetting condition and drop and substrate temperatures are the main parameters which govern the production of reproducible lens shapes. The shape and surface roughness of the lenses have been characterized by atomic force microscopy and profilometry. Their optical properties have been determined by light microscopy and spectrophotometric techniques. The printing technique can produce plano-convex spherical microlenses with diameters varying from 50 to 300 m, focal lengths from 70 m to 3 mm and f-numbers as low as 0.6.