There are different Types of microscopes : Optical, composite, stereoscopic, petrographic, confocal, fruorescence, electronic, transmission, scanning, scanning probe, tunnel effect, field ion, digital and virtual.
A microscope Is an instrument used to allow man to see and observe things that could not be seen with the naked eye. It is used in different areas of trade and research ranging from medicine to biology and chemistry.
18th-century microscopes from the Musée des Arts et Métiers, Paris
A term has even been coined for the use of this instrument for scientific or investigative purposes: microscopy.
The invention and first records of using the simplest microscope (operated through a system of magnifying glasses) dates back to the 13th century, with different attributions to who might be its inventor.
In contrast, the composite microscope, closer to the models we know today, is estimated to have been used for the first time in Europe around the year 1620.
Even then, there were several who sought to attribute the invention of the microscope, and came different versions that, with similar components, managed to meet the objective and magnify the image of a very small sample in front of the human eye.
Among the most recognized names attributed to the invention and use of their own versions of microscopes are found Galileo Galilei And Cornelis Drebbel.
The arrival of the microscope to the scientific studies led to discoveries and new perspectives on essential elements for the advance of the different areas of science.
The sighting and classification of cells and microorganisms such as bacteria are among the most popular achievements that were made possible by the microscope.
Since its first versions more than 500 years ago, today the microscope maintains its basic conception of operation, although its performance and specialized purposes have been changing and evolving until today.
Main Types of Microscopes
Optical microscope
Also known as a light microscope, it is the microscope of greater structural and functional simplicity.
It works through a series of optics that, together with the light input, allow the magnification of an image that is well located in the focal plane of the optics.
It is the earliest design microscope and its early versions are attributed to Anton van Lewenhoek (seventeenth century), which used a prototype of a single lens on a mechanism that held the sample.
Composite Microscope
The composite microscope is a type of optical microscope that works differently than the simple microscope.
It has one more mechanisms of independent optics that allow a greater or lesser degree of magnification on the sample. They usually have a much more robust composition and allow greater ease of observation.
It is estimated that its name is not attributed to a greater number of optical mechanisms in the structure, but to the formation of the magnified image occurs in two stages.
A first stage, where the sample is projected directly on the targets on it, and a second, where it is magnified through the ocular system that reaches the human eye.
Stereoscopic Microscope
It is a type of low magnification optical microscope used primarily for dissections. It has two independent optical and visual mechanisms; One for each end of the sample.
It works with reflected light on the sample rather than through it. It allows to visualize a three-dimensional image of the sample in question.
Petrographic Microscope
Used especially for the observation and composition of rocks and mineral elements, the petrographic microscope works with the optical foundations of previous microscopes, with the quality of including polarized material in its objectives, which allows to reduce the amount of light and brightness that minerals Can reflect.
The petrographic microscope allows, through the magnified image, to elucidate the elements and structures of composition of rocks, minerals, and terrestrial components.
Confocal Microscope
This optical microscope allows the increase of the optical resolution and the contrast of the image thanks to a device or"pinhole"that eliminates the excess light or out of focus that is reflected through the sample, especially if it has a greater Size than allowed by the focal plane.
The device or"pinole"is a small opening in the optical mechanism that prevents excess light (that which is not in focus on the sample) is dispersed on the sample, decreasing the sharpness and contrast that may present.
Because of this, the confocal microscope works with a very limited depth of field.
Fluorescence microscope
It is another type of optical microscope in which fluorescent and phosphorescent light waves are used for a better detail on the study of organic or inorganic components.
They stand out simply by the use of fluorescent light to generate the image, not having to rely entirely on the reflection and absorption of visible light.
Unlike other types of analog microscopes, the fluorescence microscope may exhibit certain limitations due to the wear and tear of the fluorescent light component due to the accumulation of chemical elements caused by the impact of the electrons, thus depleting the fluorescent molecules.
The development of the fluorescent microscope was awarded the Nobel Prize for Chemistry in 2014 to scientists Eric Betzig, William Moerner and Stefan Hell.
Electronic microscope
The electron microscope represents a category in itself compared to previous microscopes, because it changes the basic physical principle that allowed the visualization of a sample: light.
The electron microscope replaces the use of visible light by electrons as a source of illumination.
The use of electrons generates a digital image that allows a greater magnification of the sample than the optical components.
However, large magnifications can generate a loss of fidelity in the sample image.
It is mainly used to investigate the ultra structure of microorganic specimens; Capacity that conventional microscopes do not have.
The first electron microscope was developed in 1926 by Han Busch.
Transmission Electron Microscope
Its main attribute is that the electron beam passes through the sample, generating a two-dimensional image.
Due to the energetic power that the electrons can have, the sample must be submitted to a previous preparation before being observed through an electron microscope.
Scanning electron microscope
Unlike the transmission electron microscope, in this case the electron beam is projected onto the sample, generating a rebound effect.
This allows three-dimensional visualization of the sample because information is obtained on the surface of the sample.
Scanning probe microscope
This type of electron microscope was developed after the invention of the tunneling microscope.
It is characterized by using a test piece that scans the surfaces of a sample in order to generate a high fidelity image.
The specimen is scanned and, through the thermal values of the sample, it is able to generate an image for later analysis, shown through the thermal values obtained.
Tunneling Microscope
It is an instrument used especially to generate images at atomic level. Its resolution capability can allow manipulation of individual images of atomic elements, running through an electron system in a tunnel process that work with different voltage levels.
Great control of the environment is required for an observation session at the atomic level, as well as the use of other elements in optimal state.
However, there have been cases where microscopes of this type have been constructed and used domestically.
It was invented and implemented in 1981 by Gerd Binnig and Heinrich Rohrer, who won the Nobel Prize in Physics in 1986.
Field Ion Microscope
More than an instrument, it is known by this name a technique implemented for the observation and study of the ordering and rearrangement at the atomic level of different elements.
It was the first technique that made it possible to discern the spatial arrangement of atoms in a given element. Unlike other microscopes, the magnified image is not subject to the wavelength of light energy that crosses through it, but has a unique magnification capability.
It was developed by Erwin Muller in the 20th century and has been considered the precedent that has allowed a better and more detailed visualization of elements at atomic level today, through new versions of the technique and instruments that make it possible.
Digital Microscope
A digital microscope is an instrument with a largely commercial and widespread character. It works through a digital camera whose image is projected onto a monito or computer.
It has been considered a functional instrument for the observation of volume and context of the samples worked. It also has a much simpler physical structure to manipulate.
Virtual Microscope
The virtual microscope, rather than a physical instrument, is an initiative that seeks the digitization and archiving of samples worked so far in any field of science, in order that any interested party can access and interact with digital versions of organic samples or Inorganic solutions through a certified platform.
This would leave the use of specialized instruments behind and promote research and development without the risks involved in destroying or damaging a real sample.
References
- (2010). Obtained from History of the Microscope: history-of-the-microscope.org
- Keyence. (S.f.). Basics of Microscopes . Retrieved from Keyence - Biological Microscope Website: keyence.com
- Microbehunter. (S.f.). Theory . Obtained from Microbehunter - Amateur Microscopy Resource: microbehunter.com
- Williams, D.B., & Carter, C.B. (s.f.). Transmission Electron Microscopy. New York: Plenum Press.