Variable-focus microlenses: Issues for confocal imaging

We present the investigation of integration of Variable Focal Length (VFL) microlenses into the confocal system. VFL microlenses acting as an array of objective lenses is examined with a novel method for scanning in the axial direction presented. By variation of the focal length of the lenses the focal plane can be scanned through the sample without the mechanical movement of the sample or the objective lens, we have named this 'focal scanning'. Some of the issues related to this experiment are noted and discussed, in particular with reference to the low Numerical Aperture (NA) of the VFL microlenses available. Proposed solutions to these issues deal with the design of higher NA microlenses.