title: Sequential shrink photolithography for plastic microlens arrays.
abstract: Endeavoring to push the boundaries of microfabrication with shrinkable polymers, we have developed a sequential shrink photolithography process. We demonstrate the utility of this approach by rapidly fabricating plastic microlens arrays. First, we create a mask out of the children's toy Shrinky Dinks by simply printing dots using a standard desktop printer. Upon retraction of this pre-stressed thermoplastic sheet, the dots shrink to a fraction of their original size, which we then lithographically transfer onto photoresist-coated commodity shrink wrap film. This shrink film reduces in area by 95% when briefly heated, creating smooth convex photoresist bumps down to 30 µm. Taken together, this sequential shrink process provides a complete process to create microlenses, with an almost 99% reduction in area from the original pattern size. Finally, with a lithography molding step, we emboss these bumps into optical grade plastics such as cyclic olefin copolymer for functional microlens arrays.
authors.affiliation: Department of Biomedical Engineering, University of California, Irvine, Irvine 92697, California, USA.
authors.forename: David
authors.initials: D
authors.lastname: Dyer
authors.forename: Samir
authors.initials: S
authors.lastname: Shreim
authors.forename: Shreshta
authors.initials: S
authors.lastname: Jayadev
authors.forename: Valerie
authors.initials: V
authors.lastname: Lew
authors.forename: Elliot
authors.initials: E
authors.lastname: Botvinick
authors.forename: Michelle
authors.initials: M
authors.lastname: Khine