Microscopes are used in different settings: laboratories, schools, the workplace, and elsewhere. You might be wondering why microscopes don’t look the same. Some have simple designs while others have more parts and features. Some are big while others are small. The truth of the matter is that there are many types of microscopes and each of them has distinct features and uses.
Microscopes are categorized according to their built, functions, and the image they produce. Some microscopes use visible light while others use a sound wave or a beam of an electron. There are microscopes that produce low magnification, 2D image, and 3D image.
Optical Microscopes/Light Microscopes
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This type of microscope magnifies the specimen using visible light that is reflected on the microscope’s lens. Old microscopes are optical as shown in their simple design and construction. Many people are still using an optical/light microscope even up to this day – students, scientist, and hobbyist. (1, 2)
Light/optical microscopes are divided into the following:
1 – Compound microscope
This is the type of microscope used by students inside the laboratory. As a matter of fact, a compound optical microscope is used by students even up to this day.
How does it work?
It works by illuminating the slide that is located underneath the light bulb. The specimen on the slide is magnified by a series of lenses/objective lens (the lens near the slide) and eyepiece (the one located at the top part of the microscope). The image produced by magnification is 2-dimensional. You can adjust the clarity of the image through the lens.
- It comes with a standard design making it easy to use even by amateurs.
- It comes with high magnification.
- It is affordable – perfect for amateurs, students, and scientists.
- The image produced by the microscope is not crisp and sharp because of its lower resolution. (1, 2, 3, and 4)
2 – Stereo Microscope
A stereo microscope comes with two eyepieces, unlike the compound microscope which only has one.
How does it work?
Stereo microscopes produce 3 dimensional image through its two eyepieces that send a different image to the left and right eye. Instead of lighting the specimen from the underneath, a stereo microscope lit the specimen from above. It uses a reflected light enabling viewing of 3D subjects.
- It is the best microscope for inspection, dissection, doing circuit board work, and when working with any opaque specimen.
- It produces 3 dimensional images
- It is easy to use.
- It is fairly expensive – perfect for both amateurs and professionals.
- It is better used for solid surfaces
It comes with a low magnification which is not really good when working with individual cells. The magnification is only 100x or 200x. (3, 4, and 5)
3 – Confocal Microscopes
This is a more advanced type of microscope as it uses visible light from a laser. The sample is scanned by a laser through the use of a series of scanning mirrors, gather the image in a computer, and display the image on the screen. Another distinct feature of the confocal microscope is that it does not have an eyepiece.
- It creates a 3 dimensional image from a chosen depth of a specimen.
- It has the ability to check the structures of a non-opaque specimen.
- It can penetrate the surface of an opaque specimen deeper than the laser light.
- It is expensive.
- It is intended to use only by research scientist like the molecular biologist.
4 – Simple Microscope
Before, simple microscopes are used in the laboratory setting. Today, simple microscopes are rarely used inside the laboratory. You can find them in the industries where magnification is needed such as in the jewellery industry. A simple microscope has a powerful magnifying glass and only has one lens. Although the lens is only one, it can reach up to 100s of x magnification.
- It is primarily used to study fungi, algae, and biological specimen.
- It is used by watchmakers to magnify minute parts of the watch.
- It is used by jewelers to have a magnified view of fine parts of jewelry.
- It can be used to enlarge the letters of the book, threads of the cloth, and texture of fibers.
- It can magnify particles of different types of soil.
- It is used to check the details of stamp and engravings.
- It is used by the skin specialist to check for skin-related diseases. (4, 5, and 6)
- It does not provide enough magnification.
5 – USB Microscope
It was created more on the novelty side as opposed to professional use. However, it becomes increasingly popular today. It is a big help for people who don’t have enough money to spend on a more expensive microscope.
- It is affordable.
- With its cheap price, you get the right amount of magnification.
- It is a perfect way of introducing a microscope to kids.
It has a low magnification – typically around 50x magnification. (6, 7)
6 – Digital Microscope
It looks like the typical average microscope, but what sets it apart from the rest is its built-in LED light source. The optical view of the digital microscope can record and take photos of the image.
- It can be used for professional viewing.
- You don’t necessarily need to use an eyepiece.
- Using the LCD screen, you can easily check the focal point of the microscope for an alternative viewing method.
- It is perfect for getting quick result – you get to view numerous subjects in just a short period of time. (7, 8, and 9)
You need to connect the microscope to a power source.
|– standard design|
– easy to use by amateurs
– high magnification
This type of microscope emits an electron beams as opposed to light beams towards the target and magnify them.
(A scanning electron microscope is a huge one and will require ample space and training for proper and safe operation.)
1 – Scanning Electron Microscope/SEM
This type of microscope does not rely on light to form an image. Instead, it uses electrons. The subject is coated in gold and the electron bounces off of the 3 dimensional object so as to form an image.
- It can be used in a wide array of applications.
- It is easy to use, especially with proper training.
- It works pretty fast enabling you to complete the visualization in less than five minutes.
- You can generate the data in digital form.
- Most samples need minimal preparation actions. (4, 5, and 7)
- It is large and expensive.
- Because of its huge size, you need to store it in a place free of electric, vibration, and magnetic interference.
- Training is necessary to properly operate the microscope including sample preparation.
- It carries a small possibility of radiation exposure secondary to electrons that spread from beneath the surface of the sample. Hence, special safety precautions must be observed when using this microscope.
2 – Transmission Electron Microscope/TEM
It is intended for 2D subjects. It works the same way as projectors. It does not transmit light through the 2D subject. What it does is it transmits electrons to convey the image.
- It provides a powerful magnification; over one million times or more.
- It can be used in a variety of applications; laboratory setting, educational, and industrial sector.
- It provides a high-quality and detailed imagery.
- It provides information on both element and compound structure.
- With proper training, a transmission electron microscope is easy to operate.
- It can yield information on the subject’s shape, size, structure, and other important features.
- It is huge and expensive
- Sample preparation takes so much time.
- You need to have a special training to properly operate this type of microscope.
- The samples are limited: must be electron transparent, tolerate vacuum chamber, and small in size so as to fit in the chamber.
- It requires special housing and maintenance.
- This type of microscope is sensitive to vibration and electromagnetic fields.
- It should be placed in an area that isolates from possible exposure.
- It needs constant upkeep such as maintaining the voltage, cooling water, and currents to the electromagnetic coils. (3, 7, 9, and 10)
The table below shows the differences between the different types of electron microscope.
Scanning Electron Microscope
|Transmission Electron Microscope|
Microscopes are vast; big and small, simple and complex, and slim and wide. There are many types of microscopes and for a layperson, it is difficult to tell the difference, especially when it comes to functions. The types of microscopes mentioned above are just some of the typical microscopes you may encounter in the work setting. There is a lot more and each comes with advantages and disadvantages.