Definition : Instruments designed to obtain a magnified image of small objects and reveal details of structure not otherwise distinguishable by the naked eye. A variety of microscopes are available according to the technique used to magnify the samples and the device's intended use. The three main types of microscopes are (1) light microscopes in which the specimen is viewed by being placed in a light path (which may be white light composed of all visible wavelengths, ultraviolet light, or, less frequently, infrared light), for laboratory or surgical use; (2) electron microscopes, in which electrons are used instead of light for illumination, forming an image for viewing on a fluorescent screen or by photography, allowing for a greater magnification and resolution than is possible with the light microscope, for observing cellular and molecular structures; (3) scanning microscopes, in which a monochromatic light source delivered from a scanning laser is used. The performance of scanning-laser microscopes in terms of optical resolution, depth contrast, and sensitivity of detection is reportedly better than in conventional light microscopes. Scanning-laser microscope images are displayed on high-resolution video monitors. Microscopes are used mainly in healthcare facilities for examination, surgery, and clinical laboratory tests.
UMDC code : 12536