Different Types Of Microscope

What Is Microscope

The microscope is an instrument that is also used in the histopathology lab for the microscope. Microscopy is the process to observe any small object under a microscope for differentiation between normalities and abnormalities of the object. It is used to observe the morphology of those objects which we can’t see with the naked eyes. The microscope was discovered in 1950 by Zacharias Jansen. Zacharias Jansen lives in Netherland.

There are six types of the microscope:

  1. Light Microscope
  2. Compound Microscope 
  3. Phase-contrast Microscope
  4. Dark Filed Microscope
  5. Fluorescent Microscope
  6. Electron Microscope

1. Light Microscope

The light microscope contains a light source and a compound lens system. The lens system consists of a number of the objective lens in conjunction with a fixed (usually X10), ocular (eyepiece) lens. Light microscopes are equipped with objective lenses of low power (X10), high power (X40), and oil immersion (X100), which will result in final magnifications, in conjunction with the ocular lens, of X100, X400, and X1000, respectively.
Visualization of bacteria generally requires the use of immersion oil with X100objective. This combination results in a resolution of approximately 0.2 microns. However, the X40 objective is used for examination of wet preparations for example hanging drop, stool for ova, and cyst.

2. Compound Microscope

A compound microscope is an instrument that is also used in histopathology lab for microscopy of tissue sections to differentiate between normalities and abnormalities. It is also used for microscopy in other lab departments like hematology microbiology and clinical pathology etc.

Working Process of Compound Microscope:

First of all switch on the microscope. Now, attach the slide on the mechanical stage and adjust according to the objective lens. Adjust the eyepiece and objective lens according to the types of objects. After that adjust the slide according to the active lens (left-right, forward & backward) and focus the slide with the help of Coarse and fine adjustments. Now we observe the object under a microscope.

3. Phase Contrast Microscope

A phase-contrast microscope improves the contrast and makes evident the internal structures of cells which differ in thickness or refractive index. The different parts of a cell and its surrounding medium have got different refractive indices. When rays of light are passed through an object, they emerge in different phases depending on the difference of the refractive indices between the object and its surrounding medium.
A special optical system (special condenser and objective lens) converts difference in phase into the difference in intensity of light, producing light and dark contrast in the image. A light microscope can be converted into a phase-contrast microscope by using a special condenser and objective lens.

4. Dark Field Microscope

The reflected light is used instead of the transmitted light used in the light microscope. A darkfield condenser with a circular stop is fitted with a light microscope. This condenser lens system is arranged in such a way that no light reaches the eye unless reflected from the object. The objector bacterium appears self-luminous against a dark background. The spirochaetes can be seen under the dark field microscope.

5. Fluorescent Microscope

Fluorescence is a phenomenon that occurs when an object is impacted by a given wavelength of light and emits light at a wavelength longer than the one to which it was exposed. In a fluorescent microscope, specimens are exposed to a light of shorter wavelength (ultraviolet light), which results in the emission of longer wavelength visible light to shorter wavelengths of UV light, the resolving power can be proportionately extended.

Bacteria stained with fluorescent dyes (e.g. auramine) become visible as brightly glowing objects in a dark background, Fluorescent microscope Copy has also been employed for the detection of antigen and antibodies.

6. Electron Microscope

It is used to study the surfaces of the cells and organisms. A beam of electrons is employed instead of the beam of light used in the optical microscope. The electron beam is focussed by circular electromagnets (magnetic condenser), which are analogous to the lenses of the light microscope. The wavelength of electrons is approximately 0.005 nm, as compared to 500 nm with visible light.
The resolving power of any microscope is directly related to the wavelength, thus, the resolving power of the electron microscopes should be theoretically 100,000 times that of light microscopes but in practice, it is about 0.1 nm.
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