Out-of-plane polymer refractive microlens fabricated based on direct lithography of SU-8

To develop integrated free-space micro optical systems, out-of-plane microlenses with principle plane perpendicular to the plane of the substrate are necessary. Most of the reported microlenses are either in plane or hinged lenses fabricated in surface technologies then driven up to the required vertical position electrostatically or electromagnetically. This paper presents a research work to design, fabricate, and test a new type of polymer microlens using direct lithograph of SU-8 resist. The fabrication does not require any assembly process or external driving forces. The microlens fabricated this way has quasi-ball/spherical surface profile, which is very close to a spherical surface in the paraxial area. Lenses with different focuses can be obtained by selecting different diameters for the spherical lithography beams.(C) 2004 Elsevier B.V All rights reserved.