Whenever we think of a microscope, what usually comes into minds is a compound microscope, since this is what we experimented with during science class, and what we often see on television as well.
But, there are actually several kinds of microscopes, and each of them functions somewhat differently and serve a variety of purposes. Here is a comprehensive guide on the different types of microscopes and what each one can be used for:
What is a microscope?
First of all, let’s talk about what a microscope is, what it does, and what it’s made of.
A microscope is essentially used to study minute specimens and observe their different aspects, features, and qualities. Different microscopes function via different methods, such as light microscopy, digital microscopy, and electron microscopy. There are also other kinds of microscopy that utilize certain forms of light and sound waves to produce images.
Microscopes also have a variety of uses, ranging from casual everyday learning to highly complex academic research across various fields of sciences, such as biology, chemistry, geology, and physics. A basic microscope can be used to study somewhat large objects, while specialized and advanced microscopes can go as far as subatomic levels of a single specimen.
How a microscope is built and how it functions largely depends on what kind of microscope it is, but generally speaking, a microscope typically has objective lenses, an eyepiece, and even a camera to immortalize the image for reviewing later on.
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The first microscope
Before all the modern microscopes in this modern day and age were invented, which can give scientists valuable insight into the tiniest elements of matter, it all started with a crude and simple, yet effective, set up.
The first ever microscope invented was a simple microscope, which is essentially a powerful magnifying glass that has a magnification of 200 to 300 times. It was invented in the 17th century by Antony van Leeuwenhoek, by attaching a convex lens to a specimen holder.
This microscope is powerful enough to let you see each cell, and was pivotal in a lot of early biological studies back then. It has since been improved by adding a second lens, giving birth to the compound microscope that we know today.
Types of microscopes today
Advancements in technology have since paved the way for more modern and complex microscopes that are widely used in science classes, research studies, and more. In fact, many of these modern microscopes do not even rely on light, such as electron microscopes and scanning probe microscopes.
Here, we have three main types of microscopy, namely, light, digital, and electron microscopy. You will find various types of microscopes under each category, as well as a run down of other types of microscopes that operate on a different method.
Light microscopy is the most elemental kind of microscopy, which functions by utilizing a light source to illuminate, magnify, and view the specimen. This process requires built-in lighting on the microscope and viewing under a well-lit area. Here are the types of light microscopes:
The simplest yet most popular modern light microscope is the compound microscope, also called a compound light microscope. It is made of two or more objective lenses, a specimen holder, and a monocular or binocular (more common) eyepiece, which in itself can magnify the specimen around 10 to 15 times.
It’s also a high magnification microscope that can magnify a specimen 1,000 times, which happens as the specimen is magnified by the first lens, and the resulting image is further magnified by the second lens. This enables you to observe details beyond the naked eye, albeit with low resolution.
Since a compound microscope is a bright field microscope, it features a bright base lighting to illuminate small and semi-transparent specimens. Its simplicity and versatility make it affordable, hence its popularity in student classrooms and basic research laboratories for studying plant and animal cells, bacteria, parasites, and even drug structures.
Another type of light microscope is the stereo microscope, also often referred to as a dissecting microscope. It works by utilizing two optical paths at slightly varying angles to produce a three dimensional view of the specimen under the lenses, which can be viewed through the binocular eyepiece.
It has a much lower magnification at 10 to 300 times, often just around 100 times or lower. It comes in fixed and zoom variants, and enables you to see surface textures and manipulate specimens while viewing.
This microscope does not require slide preparation, so it’s highly suitable for large and opaque specimens. It’s highly useful in biology, especially when observing photosynthesis, as well as performing microsurgery and other medical science activities, and even in electronics such as when making circuit boards and timepieces.
There are also specialized light microscopes that are designed for specific uses in biological and medical sciences. These include dark field microscopes and phase contrast microscopes, which operate by scattering light in order to capture specific parts of the specimen like a single cell.
Meanwhile, digital microscopy operated by utilizing light microscopy principles and techniques, then converting the resulting analog image into a digital version that can be viewed on a computer screen. Here are the common types of digital microscopes:
The original digital microscope was first invented in Japan towards the end of the 1900s. It’s a high magnification microscope that may come with or without an eyepiece, and connects to a computer via a USB cable.
This type of microscope enables you to see well beyond the naked eye, and has the ability to capture and record both still and moving images for long periods of time.
The resulting imagery is viewed through computer software as the microscope camera converts the magnified analog images into a digital version that you can save into the computer’s memory, or send via email.
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USB computer microscope
Not essentially a digital microscope, the USB computer microscope is a simplified version of a modern light microscope. It is composed of a macro lens and specimen holder, as well as a USB cable to connect to your computer for viewing specimens.
This microscope allows for a maximum of 200 times magnification, although it has a shallow depth of field, so it’s just adequate for viewing semi-large specimens and studying their overall details and features.
It’s a simple and inexpensive microscope that’s suitable for kids and hobbyists who want to study just about any specimen without having to prepare them first.
The smallest microscope ever invented is the pocket microscope, which is a small and handheld digital microscope that is used for hand-held imaging of objects and specimens during field explorations, or even inside laboratories.
It’s a somewhat simple microscope with a relatively low 25 to 100 times magnification, and is often used in biology and geology to identify small specimens or look at the features of semi-large objects.
When it comes to advanced microscopy techniques, electron microscopy works by using beams of accelerated electrons to illuminate the specimen, which can be anywhere from macromolecular to a few nanometers in size. Here are the types of electron microscopes:
Transmission electron microscope
The first type of electron microscope invented was the transmission electron microscope, which can produce two dimensional images of a single nanometer. It functions by preparing thin, small, and semi-transparent specimens into a slide, placing them in a vacuum environment, and having electron beams pass through.
It’s a powerful and high magnification microscope that is perfect for nanotechnology since it has the power to produce images at the atomic level. It can even be used for studying live specimens.
This kind of microscope is most often used in fields like semiconductors, as well as physical and biological sciences, forensics, and metallurgy
Scanning electron microscope
Another electron microscope is the scanning electron microscope, which uses electron beams to scan images in vacuum or vacuum like conditions. It’s ten times less powerful than transmission electron microscopes, but can generate higher resolution images in three-dimensional black and white.
Unlike the transmission electron microscope, this operates by bouncing the electrons off the surface of the specimen, which needs to be prepared by dehydrating it then coating it with a conductive material such as gold or palladium.
Aside from physical and medical sciences such as biology and chemistry, this microscope is also used for gemology and metallurgy and is designed to study the composition, morphology, topology, and crystallography of specimens such as insects and bones, as well as any cellular component, bacteria, or virus present.
Reflection electron microscope
A specialized form of electron microscope is the reflection electron microscope, which is designed to study crystals and the structure and composition of their surfaces. This works by having a narrow beam of accelerated electrons refracted from the crystal’s initial atomic layers. It produces a high-resolution image of up to a single nanometer when combined with light dispersion or spectroscopy.
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Other types of microscopy
Finally, there are also other types of microscopy that don’t exclusively operate via light, digital, or electrons. Instead, these utilize various forms of light and sound waves to produce and capture specimen images. Here are some microscopes in this category:
The fluorescence microscope is a popular type of laser light microscope. It’s also referred to as a confocal microscope, since its confocal point is what produces a detailed image of the specimen. It features a dichromatic mirror and is attached to a computer screen.
This microscope enables you to isolate and view structures and aspects of a specimen by altering how the image is produced in the microscope. This works by scanning dyed samples using different colors of light that interact in a specific way with certain dyes applied to the specimen.
It is often used in biology and medicine for studying cell proteins and identifying bacteria in an organism. It’s a high resolution and high magnification microscope that can also produce three-dimensional images by combining multiple scans of a specimen.
When it comes to studying and observing living cells, an X-ray microscope is often the most suitable option, since it doesn’t require any specimen sample preparation. It operated by emitting a beam of invisible X-rays that do not easily reflect or refract.
It’s a high magnification microscope, better than an optical or light microscope, and can produce images at the atomic level.
Scanning probe microscope
A sophisticated and delicate microscope that is often seen in academic and industrial fields is the scanning probe microscope, which functions by scanning the surface of a specimen and produces highly magnified three-dimensional images.
It’s arguably better than light and electron microscopes, and can be used for standard analysis, research and development programs, and studies in the biological, chemical, and physical sciences.
Finally, there’s also the acoustic microscope, which is an intra-cavity imaging tool that utilizes high ultrasound waves to find cracks, faults, and errors from various samples. The beam scans and penetrates the specimen while it’s submerged in water.
It’s equipped with point focusing technology, enabling you to internally view the sample without damaging or staining it, so it’s most often used in quality checks for product manufacturing industries.
Remember, a microscope is a device that is used to study small objects and specimens by the use of light or other matter. There are dozens of types of basic and specialized microscopes that fall under specific types of microscopy, and each one has a variety of purposes.
Nowadays, the most common microscopes are compound and stereoscopic microscopes, both of which you can find in most science classrooms and laboratories. These are affordable and versatile microscopes that are highly suitable for learning.
When it comes to advanced microscopes, research industries often utilize electron and scanning probe microscopes, since these are high resolution and high magnification microscopes that can be used on a variety of specimens.