Light Microscope

November 1, 2021

One of the basic tools used in a laboratory is the light microscope , this instrument is the result of hard work carried out over many centuries of science. First came the invention and use of the lens, then perfection, and finally enlightenment.

This type of microscope gets its name because it allows unaltered light to pass through a system of lenses , in order to produce a bright field where small objects are observed.

What is a Light Microscope?

It is an instrument whose purpose is to observe elements that are difficult to see with the naked eye. The word microscope in Greek means, micrós that is small and scopeo to look at.

The light microscope was first seen in the age of microscopy in the 17th century. It is one of the simplest and most basic types when talking about microscopes. Its operation is based on the set of lenses and the use of visible light that helps to increase the image of a sample.

What is the Light Microscope for?

The light microscope is used to observe and analyze elements or particles that are invisible to the naked eye and that are often key in scientific research.

It has a magnificent image that allows you to see small structures in detail, through the optical system, which aims to direct natural or artificial light in order to illuminate the element and thus be able to observe it under the microscope.

How does the Light Microscope work?

To obtain the expected results of the observation, through the light microscope, it is necessary to know how this research and diagnostic instrument works. Also, know what its parts are and the function of each one.

The light microscope or optical microscope, consists of two parts, a mechanical and an optical. The mechanics are:

  • Foot: corresponds to the base of the microscope
  • Column or Arm: it is the vertical metal support that joins the base with the optical tube
  • Optical tube: it is the metal cylinder where the ocular lens is
  • The rack: used to raise and lower the stage, where the object of study is placed
  • Coarse screw: this device allows the stage to be raised and lowered quickly. The approach it allows is rough
  • Micrometer screw: used to move the stage slowly, obtaining a fine focus
  • Drive screw: its function is to move the stage as indicated by its name, in the shape of a cross, forward, backward, right or left
  • Platen: quadrangular plate with a central opening that allows light to pass through. Located at the bottom of the column
  • Slide: sheet on which the study object or sample is placed
  • Revolver: made of metallic material, allows the different objective lenses to be screwed on

The optical parts of the microscope, meanwhile, are:

  • Eyepiece lens : is on the top of the optical tube and is in direct contact with the eyes. Amplifies the real and inverted size of the objective lens
  • Objective lens: short tubes attached to the revolver, at various magnifications
  • Diaphragm : disk that is located between the stage and condenser. Regulates the amount of light that is projected onto the stage
  • Condenser : made up of several lenses, it allows concentrating the light rays that the light source projects towards the sample
  • Light source : is the light located at the foot of the microscope. Has various intensities

Okay, now that we know how the light microscope is composed, let’s move on with its operation, which is based on a lens system, which we mentioned previously, the eyepiece and the objective.

In the first place, the light source, whose light passes through the sample from below, forms a primary image on the objective that is magnified and projected towards the eyepiece, which behaves like a magnifying glass, increasing the primary image and turning it into the so-called secondary image.

This image enlarged by the eyepiece, known as the virtual image, then reaches the retina, finally being seen by the observer, who perceives it as if it were in a different plane, beyond the real sample.

As you can see, it is a simple process, it is the optical theories that add complexity to the process.

Use of the Light Microscope

It is a very useful equipment in relevant scientific investigations of the sciences of geology, biology, physics, chemistry, among others.

Likewise, it is used in the light microscope in histology and pathological anatomy, since diagnostic studies can be done, including pigments, crystalline structures, lipids, proteins and bone deposits.

Types of Light Microscope

When talking about the light microscope, it is important that you know that there are different types of them, among them the following stand out:

  • Compound microscope

It is a very simple device, since two or more lenses are used to achieve the magnification of the image.

  • Monocular microscope

It has only one eyepiece, thus allowing the sample to be viewed with only one eye. It is simple and is used a lot by students or fans of this type of device.

  • Microscopio binocular

It has two eyepieces to be used by both eyes. The image is distributed in two equal parts through a visual prism.

  • Trinocular microscope

It has two eyepieces, which aim to see the elements through both eyes. It also has an eyepiece, which is connected to a camera, which captures the images that are observed.

  • Digital microscope

Instead of using an eyepiece, it has a camera that is responsible for digitally capturing the images of the element.

  • USB microscope

Like digital, it captures images digitally, and is used very frequently for daily tasks.

  • Inverted microscope

The sample being observed is illuminated from above, that is, the position of the light source and the objective is opposite to that of the microscope. Its advantage is that you can see what is in the background.

  • Stereoscopic microscope

It also has two eyepieces. It offers varied results and with 3D effects.

  • Ultraviolet light microscope

The illumination offered by the sample or the element being observed is with ultraviolet (UV) light. Quality resolution and better contrast are achieved.

  • Polarized light microscope

The direction of light is very punctual. It is used to observe minerals, rocks and crystalline objects.

  • Fluorescence microscope

In this type of microscope, fluorescent substances must be used so that the results are better observed.

Knowing each of the microscopes that you can find in a laboratory will be of great help in handling them properly, in each of the analyzes that need to be carried out.

Light Microscope Features

To better understand the way in which light microscopes work, it is important that you know the characteristics and parts that it has. Next, I show you each one of them:

  • Ocular

Depending on the type of microscope, they have one or two ocular lenses, which is the means used to observe the element or sample. This is the one that captures and enlarges the image formed in the objectives

  • objectives

It has a lens that is located on the revolver, which is intended to enlarge the image and allow you to see through the eyepieces.

  • Diaphragm

It is responsible for regulating the light that enters the condenser.

  • Condenser

This is nothing more than the lens that has the purpose of concentrating the light rays.

  • Focus

It is the part of the microscope that transmits light rays to the device.

  • Revolver

He is the one who has the objectives and the variety of increases. He rotates in order to use a magnification that is going to be linear with the eyepiece.

  • Macro and micrometric screws

Light microscopes have focusing screws, which are what will move the stage or tube up and down. With the macro the displacements of greater magnitude are carried out and with the micro the short ones and those with the precise direction.

  • Platinum

It is a surface where you can place the preparation so that the rays that come from the light source can be projected.

  • Arm

It is the solid structure where the tube, the plate and the screws are fastened.

  • Base or foot

It is the bottom part of the device that makes it stand upright and stable.

Once you know what the parts of this great instrument are, you will know how to manipulate it simply and easily.

Importance of the Light Microscope

The light microscopes have become for science and research in an important and essential tool, because they are becoming more interesting and useful time for the guild scientist. As well as people who use it continuously as students, teachers, doctors, among others.

For this reason, this device has progressively evolved in recent years.

The light microscope, without a doubt, is an essential element for any laboratory where a variety of studies are carried out. It is a tool that has opened the doors to the small world, making it visible to the human being.

Dr. Loony Davis5
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Born and raised in Brussels in an English family, I have always lived in a multicultural environment. After several work experiences in marketing and communication, I came to Smart Water Magazine, which I describe as the most exciting challenge of my career.
I am a person with great restlessness and curiosity to learn, discover what I do not know, as well as reinvent myself daily, someone who is curious about life and wants to know. I enjoy sharing knowledge.
This is my personal project but I also collaborate in other blogs, it is the case, the most important web on water currently exists in the US, if you are interested you can read my articles here.

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