How microscopes work.

One of the most remarkable inventions in the history of science has been the microscope; with it you can display elements imperceptible to the human eye. Through this article we invite you to know how microscopes work.


This particular and famous object used primarily in areas that involve science, is a tool that allows us to observe, analyze and study very small particles (living or inert) that are not reached with the naked eye.

By placing the sample under the lens of a microscope, an amplitude of the image is produced that opens up a whole interesting world to explore and study.

A point to note is that since their creation at the end of the 16th century, microscopes have improved our knowledge of basic biology, biomedical research, diagnostics, and various scientific contexts.

How do microscopes work?

To know how a microscope works, you basically need a sample that will be the object of study, a light source and an optical system. To compose an image, the element must be illuminated with a certain type of light that will allow the amplified image to be created.

In optical systems, the objective is the primary imaging instrument. As optical systems, we can cite as an example:

  • The human eye
  • A camera
  • A magnifying glass
  • A projector
  • A microscope
  • A telescope

Scientists agree that the human eye, along with the brain, is the most efficient image processing system available today in terms of speed and resolution.

In a microscope, magnification alone is not enough. It takes the resolution and ability of an optical system to split two points very close together to determine what will be seen.

Types of microscopes

Microscopes can be classified according to several considerations: whether it is the support used to illuminate the sample, according to the number of lenses, the number of eyepieces, the transfer of light or even its scope.

Optical Microscope

It works by taking into account the properties of matter to change the direction of light rays. With the combination of special lenses, which help to split or converge these light rays, a larger image can be achieved.

This in turn uses a set of lenses, some on the object to be viewed and others located in the eyepiece. It's like this:

  • The object lens causes an enlarged image of the sample.
  • The image that was produced first is enlarged by the lens of the eye, generating a virtual image much larger than the object in question.

This type of microscope necessarily needs to use light for its operation. Therefore, they come with a light source and a condenser that focuses the light that falls on the sample.

As light passes through the sample, the lenses are responsible for directing the light to create a larger image.

Electronic Microscope

This uses electrons to give structure to the image (instead of light like optics). It is made up of a support (to emanate the electrons), a camera (to isolate the sample to be viewed and be able to calculate exactly) and a monitor (to observe the final product); several attach a scanning system to save the images.


In the upper part is the Canon (it has a tungsten filament that is responsible for emitting the continuous electron beam), the beam will pass through an Anode (positive pole to direct the electrons) and finally a condenser lens and a deflection coil (which performs electronic filtering, to obtain a point-by-point image).


The main room is the sample (object to observe and study), which is usually covered with a small layer of gold to maximize precision The electron beam hits the sample, what we would call a reflection, which produces a signal (reaction of electrons to contact with the sample).

To know about this signal, a secondary electron detector is needed, that is, a detector that can "read" said signal. The detector collects information, amplifies it and shapes it so that it can be viewed.


You have the image ready thanks to the secondary electron detector, a defined image. That is, the sample is already visualized under the microscope.

Ultraviolet light microscope

Irradiate the shot with ultraviolet (UV) light; the frequency distance of this type of light is shorter than the perceivable one. In addition, high resolution and contrast are obtained in the results of this device, since shots can be observed that appear to be transparent when viewed under normal light.

Polarized light microscope

It is an optical microscope to which a pair of polarizers are added. The direction of light in this microscope is specific and very effective in visualizing translucent samples, stones and minerals.

Fluorescence microscope

In this case, the device uses fluorescent substances that generate the image of the sample. The sample is illuminated with a xenon or mercury vapor lamp. To isolate the light coming from the object, special filters are placed.

Parts of a microscope

We know that there are different types of microscopes, however, there are parts and components in common between them. Such as the following:

  • Ocular: is responsible for enlarging the image that is formed in the lenses. This is the lens next to the explorer's eyes.
  • Objectives: are the lenses located on the revolver. They are responsible for expanding and forming a virtual image.
  • Diaphragm: it is a type of gate that normalizes the amount of glowing energy that must arrive at the condenser.
  • Condenser: lens that agglomerates or gathers the light beam.
  • Focus: is in charge of directing the light beam towards the condenser.
  • Revolver: This is a mobile device that can rotate and this is where the various magnified targets are located. This confers the distribution of the objectives with the eyepiece.


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