The microscope is one of the main laboratory instruments in the laboratory. Different microscopes have different magnifications, in general with the help of different lenses, the image of the sample would be multiplied. The general principles in all types of microscopes are based on the crossing the light with different wavelengths from several convex lenses. The shorter the wavelength of light used in the microscope, the greater the resolution of the microscope. For example, the resolution of the human eye is 1.0 mm while at the same time that of a conventional light microscope is 0.24 microns.
Types of microscopes:
The light source in this microscope is visible light in which passes through several convex lenses that are embeded in it , also a prism that changes the direction of light (resolution of 24.0 microns).
Ultra Violet Microscope:
Ultraviolet microscope, or U.V microscope,in which the light supplement source is U.V. It has a higher resolution than a conventional light microscope because ultraviolet rays have a shorter wavelength than visible light. The objective lens used in this microscope is made of quartz. Due to the harmful UV rays to human eyes, after the image of the object was taken ,it is sent on the monitor screen to be visible (600 angstrom resolution).
In general, materials are of two types in terms of fluorescence:
– The primary fluorescence in which are inherently fluorescent and emit light themselves, such as vitamins and dyes.
– Secondary fluorescence in which does not have fluorescence properties and we induce fluorescence properties with various dyes and reagents such as berberine sulfate and acridine orange.
The light source in this microscope is U.V.
Dark Field Microscope:
The power supply of light in this type of microscope is visible light . by creating refraction of light through convex and concave mirrors the object or our sample ,could be seen transparent and luminous on a black background.
Phase Contrast Microscope:
The power supply of light in this type of microscope is visible light and is used to examine tissues or samples that have a small optical refractive difference. For this purpose, a perforated plate called phase plate is installed in the condenser.
It is the most advanced microscope of the present century, with a resolution of 2 angstroms. In this microscope, by passing electron beams emitted through a very low tungsten wire strand of multiple lenses, the object would be visible and that is after photographing on a fluorescent screen or monitor screen.