ABSTRACT
This chapter focuses on examples of microlenses made of solids whose focal lengths cannot be tuned during their operations. Microlenses with fixed focal lengths whose focal points are shifted by moving their positions are also discussed in this chapter. These non-tunable microlenses include:
Ge/SiO2 core/shell nanolenses Microlens arrays fabricated through molding processes Injection-molded plastic lenses Lenses formed by thermally reflowing photoresists (PRs) Self-assembled supermolecular nanoscale spherical lenses Lenses made by graded exposure in PR Lenses fabricated by direct photo-induced polymerization Strain-responsive lens arrays Lenses latched by electrowetting Lens arrays fabricated from melting polystyrene beads Lens arrays fabricated by dewetting methods Lenses formed from inkjet printing
Fixed focal length microlenses and arrays with lens diameters of a few to several hundred micrometers are extensively used in many optical systems such as projection lithography [1-3], optical coherence microscopy (OCM) [4], Shack-Hartmann sensors [5], and back lighting for projection liquid crystal displays (LCDs) [6].
