Light Microscopy & Imaging

Light microscopy for materials analysis generally refers to reflected light microscopy. In this method, light is directed vertically through the microscope objective and reflected back through the objective to an eyepiece, view screen or camera. Transmitted light is occasionally used for transparent and translucent materials. For some low-magnification work (stereo microscopy), external, oblique illumination can be reflected off the sample into the objective. Magnification of the sample image is obtained by light refraction through combinations of lenses, comprising objectives and eyepieces. The minimum feature resolution is about 0.2 µ, but smaller features, as small as about 0.05 µ, can be detected by image contrast enhancement with polarized light, interference contrast, and dark field illumination methods. Images can be recorded on traditional films or as digital files for computer display storage and analysis.