Major types of optical microscopes include bright field microscopes, dark field microscopes, fluorescence microscopes, phase-contrast microscopes, and differential interference microscopes. Such microscopes have characteristics and features that are unique in terms of the light emitted or absorbed by an object to be observed. For example, a fluorescence microscope distinguishes differences in structure by detecting the concentration distribution of a fluorescent substance or in the fluorescence spectrum when the object emits fluorescence. Bright and dark field microscopes distinguish the target of observation from other objects based on the absorption/reflection and scattering of light, respectively. All of these microscopes have to condense the light from the objects with lenses.
KeywordsNumerical aperture Bright field image Dark field image Fluorescence