Characterization of a polymer microlens fabricated by use of the hydrophobic effect

We report a means of fabricating hydrophilic domains in a hydrophobic background by lithographically patterning an adhesive hydrophobic layer. Polymer microlenses were fabricated on these substrates by use of a dip-coating technique. Various lens shapes (circular, elliptical, square) were fabricated on a variety of substrates (SiO(2), SiN, GaAs, InP, etc.), ranging in size from 2 to 500 microm in diameter, with fill factors of up to 90%. Plano-convex and double-convex lenses were fabricated, with f-numbers as low as 1.38 and 1.2, respectively. Optimum lens surfaces deviated from spherical by just +/-5 nm . The lenses are stable at room temperature and exhibit minimal degradation after 24 h at 105 degrees C. The transfer of these polymer lenses to an underlying substrate was also demonstrated.