An Inexpensive Reflected Darkfield Epi-Illuminator for a Standard Polarized Light Microscope

The analysis of environmental particles often requires reflected or epi-darkfield illumination. For example, an opaque spherical particle might be a cenosphere from a diesel engine, a fungal spore, a toner sphere, insect frass, a paint sphere (of any color), flyash, or a magnetite sphere, just to name a few possibilities. Reflected darkfield illumination and the ability to quickly change the type of illumination without moving the slide removes the uncertainty. The assessment of combustion residues in environments exposed to smoke from a fire has been plagued by the assumption that discovery of opaque particles equates to discovery of combustion residue. For the microscopist, the absence of immediately available reflected darkfield illumination and the inability to change the type of illumination quickly without moving the slide is a critical flaw in the analysis. There is a relatively inexpensive solution to the first problem, i.e., a darkfield epi-illuminator, using LED technology, designed to fit on a standard polarized light microscope (PLM) objective.