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an instrument used to obtain an enlarged image of small objects and reveal details of structure not otherwise distinguishable.
acoustic microscope one using very high frequency ultrasound waves, which are focused on the object; the reflected beam is converted to an image by electronic processing.
binocular microscope one with two eyepieces, permitting use of both eyes simultaneously.
compound microscope one consisting of two lens systems whereby the image formed by the system near the object is magnified by the one nearer the eye.
darkfield microscope one so constructed that illumination is from the side of the field so that details appear light against a dark background.
electron microscope one in which an electron beam, instead of light, forms an image for viewing, allowing much greater magnification and resolution. The image may be viewed on a fluorescent screen or may be photographed. Types include scanning and transmission electron microscopes.
fluorescence microscope one used for the examination of specimens stained with fluorochromes or fluorochrome complexes, e.g., a fluorescein-labeled antibody, which fluoresces in ultraviolet light.
light microscope one in which the specimen is viewed under ordinary illumination.
operating microscope one designed for use in performance of delicate surgical procedures, e.g., on the middle ear or small vessels of the heart.
phase microscope (phase-contrast microscope) a microscope that alters the phase relationships of the light passing through and that passing around the object, the contrast permitting visualization of the object without the necessity for staining or other special preparation.
scanning electron microscope (SEM) an electron microscope that produces a high magnification image of the surface of a metal-coated specimen by scanning an electron beam and building an image from the electrons reflected at each point.
simple microscope one that consists of a single lens.
slit lamp microscope a corneal microscope with a special attachment that permits examination of the endothelium on the posterior surface of the cornea.
stereoscopic microscope a binocular microscope modified to give a three-dimensional view of the specimen.
transmission electron microscope (TEM) an electron microscope that produces highly magnified images of ultrathin tissue sections or other specimens. An electron beam passes through the metal-impregnated specimen and is focused by magnetic lenses into an image.
x-ray microscope one in which x-rays are used instead of light, the image usually being reproduced on film.
a visual and photographic microscope in which electron beams with wavelengths thousands of times shorter than visible light are used instead of light, thereby allowing much greater resolution and magnification; in this technique the electrons are transmitted through a thin section of an embedded and dehydrated specimen maintained in a vacuum.
Any of a class of microscopes that use electrons rather than visible light to produce magnified images, especially of objects having dimensions smaller than the wavelengths of visible light, with linear magnification approaching or exceeding a million (106).
e·lec·tron mi·cro·scope(ĕ-lek'tron mī'krŏ-skōp)
A visual and photographic microscope in which electron beams with wavelengths shorter than visible light are used instead of light, thereby allowing much greater resolution and magnification; in this technique, the electrons are transmitted through a very thin section of an embedded and dehydrated specimen maintained in a vacuum.
electron microscope (EM)a microscope that produces high-resolution images by the interaction of electrons with the specimen, the electrons being guided by electromagnetic lenses. There are two major types of EM:
- transmission electron microscope (TEM). The beam of electrons passes through the specimen of e.g. thinly-sectioned tissues, and is focused onto a flurorescent screen or a photographic film. Magnifications well in excess of × 250 000 are possible, with a RESOLUTION of less than 1 nm.
- scanning electron microscope (SEM). The specimen (which can be whole cells or tissues) is bombarded with high-energy electrons causing generation of low-power, secondary electrons from the specimen surface, which are collected to form an image of the surface. Magnifications in excess of × 100,000 are possible, with a resolution of about 5 nm.
e·lec·tron mi·cro·scope(ĕ-lek'tron mī'krŏ-skōp)
Visual and photographic microscope in which electron beams with wavelengths thousands of times shorter than visible light are used instead of light, thereby allowing much greater resolution and magnification.