History of the electron microscope


Humankind is consistently interested in the things that make up our reality. We ask questions about the environment and the beginning of it. Humans develop a hunger for learning, and that has to be satisfied. We discovered and developed science to help us answer our inquiries.

Tick under microscope

Science made our lives easier by making innovations and progressions for the betterment of everyone. It made developments that benefit us today. What made things possible are the splendid minds and the hardware and materials made for our advancement. Instruments helped us make incredible jumps in material science, biology, physics, chemistry, and others. 

Some things used to be outlandish, but now, everything is within our reach.

An integral and extraordinary asset made for the development of science is the microscope. We can now observe things that are not obvious to the unaided eye. One of the first to exist is the optical microscope. It allowed the discovery and observation of the cells and many others. It lets us learn so much more than we used to. It may be useful, but it has limitations, like how it cannot let us see nanoscale objects. It can only provide a magnification of up to 1000x. Of course, this posed a problem for our scientists. They are wanting to see more than what the optical microscope allows them to see. They need to know what makes up the smaller things in our environment. Someone came to solve that; it was Ernst Ruska. 


Ernst Ruska was a German professor and engineer. He had a vast knowledge of electron wavelengths, which allowed him to have an idea and develop the electron microscope. He knew that it is the answer to the limitations of the optical microscope. He invented it in 1931, while he was studying at the Technical University of Munich, under Dr. Max Knoll. Together, they were able to develop the first electromagnetic lens, which is a key element of the electron microscope. 

To Ruska, the electron microscope is the solution to the problems of the optical microscope, but in his first product, the results did not differ too much. That is, of course, there is still more to improve. In the late 1930s, he was able to make significant modifications to make a powerful microscope. He then worked as an electrical engineer in the Siemens company, the manufacturer of the first electron microscope. He, together with two other scientists, won the Nobel Prize in Physics in 1986.

The electron microscope, until today, is considered powerful equipment for science. It is able to produce high-quality images of samples one nanometer in size. It is capable of 1000x to 2000x magnification. It is still essential to Biology, Forensics, Medicine, and others. 

How It Works

The electron microscope is quite large, costly, sensitive, needs maintenance, and requires the user to have training. Despite that, it is still a must-have for big laboratories. To house the electron microscope, it has to have a special room that will protect it from disturbances that may interfere with its image production. The place should be a low vacuum or a variable pressure chamber. It should also have sufficient electricity and water, to cool it down. The electron microscope will also need a digital display for viewing and computer interfaces and software for image analysis. 

Scanning electron microscope in a commercial environment

The concepts and ideas of an optical microscope are also applied in the electron microscope, but instead of using photons of light, it uses electrons. Since it is highly sensitive, the samples need to be processed before you can view them in the microscope. You may use fixation, embedding, dehydration, and others. Most require special training, so the work can be done properly. 

In producing the image, the electron microscope provides topographical and physical data. It can tell you the size, shape, texture, and others. It has a thermionic gun that lets electron beams pass through, and coils or solenoids that bend those beams to get the information and create a symmetrical display of the sample. The electrons in the beams will interact with the electrons in the specimen in the form of signals. Its resolution can be changed by increasing or decreasing the voltage use.


There are two types of electron microscopes based on what they are for and what they can do. 

  1. Transmission Electron Microscope (TEM)

The transmission electron microscopy is better suited to provide information about internal composition, and its samples need to be cut thinly. It is very similar to the optical microscope. TEM can produce black and white images but needs a high voltage to get high resolution. The display produced can be viewed on a screen or transferred to a photographic plate. However, the TEM also has some problems with spherical and chromatic aberrations.

  1. Scanning Electron Microscope (SEM)

The scanning electron microscope is for providing information about surface texture and topography. Because of the coils, the electron beams scan the sample to accurately get its physical feature. Compared to a transmission electron microscope, SEM is less powerful but can provide high-resolution, black, and white images.

To effectively use the microscope, make sure that you will provide its needs, and take care of it. Despite its many requirements to operate correctly, it is a powerful tool for science, manufacturing, industry, and others. It is a great investment for the sectors that can highly benefit from it. 

Now that we know that powerful equipment is invented so humans can learn more and make discoveries, we should know that science will not stop. People will always be curious and will try to find answers to several questions.

Like the optical microscope, the electron microscope will also have limitations that will hinder the discovery of some things, and our scientists will seek solutions for that. More of them will be like Ernst Ruska, able to make great leaps by inventing something to help others. Many more innovations will come after the electron microscope and we have to be ready for them, they will always be worth it.