Types of Microscope

There are several different types of microscopes. We use a microscope for various purposes in schools, research labs, laboratories, commercial enterprises, and many others.  

The most common and widely used microscope types are the stereo microscope, compound microscope, phase contrast microscope, and digital microscope. All of these are used for different purposes and chosen according to the need. For example, if you want to examine a gem or rock, a stereo microscope is a good choice. However, compound microscopes are preferred to observe cells and living tissues.

So are you interested in finding out about 4 different types of microscopes, their features, advantages, and uses? Keep on reading:

Kinds of Microscopes

Stereo Microscope

The stereo microscope is also known as a dissecting microscope. Unlike an ordinary light microscope, it creates a 3-dimensional image of the object. It has two separate objective lenses and an eyepiece, creating two separate optical paths.

This creates an image at slightly different angles in each eye.

Features

• Binocular
• The magnification power of 20x to 50x
• Creates three-dimensional images
• Spatially separated optical paths
• Views opaque specimens

Stereo Microscope Parts

A stereo microscope has the following parts

Stereo head

The stereo head is the topmost portion, which holds the two eyepieces. It is movable.

Eyepiece

A stereo microscope has two eyepieces, each for an eye. The eyepieces have a magnification power of 10x. You can also use optional eyepieces of magnification up to 30x.

Diopter

It is an adjustment ring that prevents eye strain. Its basic function is to manage focus differences between the two eyepieces.

Objective Lens

A stereo microscope has two objective lenses. Each one of these objectives easily switches its magnification and connects to a separate eyepiece.

Focus Control

Stereo microscopes have only a Coarse adjustment knob. The coarse adjustment knob moves the head of the microscope up and down to bring the specimen into sharp focus.

Stage

The stage is the place where the specimen is placed. It has stage clips to hold the specimen in place.

Illumination

Most stereo microscopes use a top light known as Transmitted illumination, but some also have light at the bottom known as incident illumination.

Uses of Stereo Microscope

Stereo microscopes are used to view macro objects, creating a 3-dimensional image. They can be used by coin collectors, a technician to repair circuits, biologists for dissection, paleontologists, in the textile industry, etc.

Types of Stereo Microscopes

Stereo microscopes are categorized into five total types according to different classifications. The two main types are Greenough Stereo Microscope and the Common main objective Stereo Microscope considering their invention and additional features in the latter.

The other classification gives us Fixed, Zoom, and Turret stereo microscopes. Slight changes in their structure and function make them unique. Let’s tell you about all the different types of Stereo microscopes in one place.

Greenough Stereo Microscope

The Greenough Stereo Microscope was first introduced by American biologist Horatio S. Greenough in 1890. The design consists of two identical yet separate systems connected to one stage. The microscope has two prisms that ensure that the image is upright and properly oriented. These are among the earliest microscopes and are produced by many eminent manufacturers today.

Common Main Objective Stereo Microscope

The American Optical Instrument Company invented the Common Main Objective Stereo Microscope (CMO) in 1957. It is used for more precise and complicated applications than the Greenough Stereo microscopes. Besides the system’s basic structure, you can attach other features like an iris diaphragm, fluorescence attachment, illumination, and ergonomic features for more convenient usage. It offers two parallel bean paths and better resolution and higher magnification than the previous ones.

Stereo Fixed Microscope

A stereo fixed microscope has a fixed magnification by two objective lenses. As the magnification is fixed, you have to install a new eye eyepiece to get a higher magnification when needed.

Stereo Zoom Microscope

The Stereo zoom microscope is the most widely used stereo microscope as you can easily increase or decrease the magnification through the zoom knob. It also enables you to change the eyepiece. You can find two varieties in stereo zoom microscopes depending on their stand.

Simple Stand: You can use this one to observe your specimen or repair it if needed.

Boom Stand: It is for complex applications, and you can mount it on the floor. Boom stand stereo microscope is a little expensive and usually used by biologists or researchers.

Stereo Turret Microscope

Apart from the zoom microscope, the stereo turret microscope also comes with multiple mountings. The turret is one of the choices and contains an extra objective lens for you to rotate and observe as per the requirement of your position. It also allows alternating the magnification by rotation of the mounting. Though it performs numerous functions, it is also more affordable than other stereo microscope options.

Compound Microscope

If you have seen a microscope in your school laboratory, it’s probably a compound microscope. Compound microscopes are one of the simplest types of light microscopes typically used in schools to describe the basic workings of a microscope.

The compound microscope is also known as a biological microscope. It uses a series of lenses to create a highly magnified image of the object. Light from the object falls onto the objective lenses, which creates a magnified image that is further magnified by the eyepieces.

Features

• Monocular, binocular and Trinocular
• Magnification up to 1000x
• Used to view cells
• 2-dimensional images

Parts

A compound microscope has structural parts for support and optical parts for magnifying the specimen. The following are the structural and functional components of a compound microscope.

Eyepiece

The Eyepiece is also known as an Ocular lens. It is present at the top of the body tube. The magnification power of the eyepiece ranges from 5x to 30x.

Body tube

The body tube holds an eyepiece at the top and objective lenses at the bottom.

Nosepiece

The revolving nosepiece has a circular ring that is movable and holds the objective lenses.

Objective Lens

A compound microscope has four objective lenses of magnification 4x, 10x, 40x, and 100x magnification.

Stage

The stage is the place where the specimen is placed on a slide. It has stage clips to hold the slide in place.

Iris Diaphragm

The Iris diaphragm is a circular opening in the stage through which light reaches the specimen.

Condenser

A condenser lens focuses the light rays onto the specimen. There are two condenser lenses. They are essential for image clarity.

Coarse adjustment and Fine adjustment Knobs

The coarse and fine adjustment knobs move the space up and down to bring the specimen into focus.

Illumination

A light source illuminates the object. Some have a mirror that reflects incident light on the specimen. Most modern compound microscopes have an LED bulb to illuminate the object.

Base

The base provides stability to the compound microscope.

Used of Compound Microscopes

Compound microscopes are widely used in schools and research labs to study biological and microbiological specimens that are not visible to the naked eye. Researchers can observe tissue, cells, and organelles such as mitochondria and nuclei with a kind of microscopes of high magnification up to 1000x.

Types of Compound Microscope

Besides being used in schools to examine a specimen, different compound microscopes are used for various other purposes. The four most common types of a compound microscope are:

Laboratory Microscope

Routine microscopes are heavy and large and contain more components than student microscopes. Laboratory microscopes have an illumination, condenser, revolving nosepiece, focus lock, mechanical stage, and a large base for easy observation. Some of these microscopes also have a binocular head to make longer observation times less tiring.

Characteristics and uses of Laboratory Microscope:

• They are bigger and heavier
• They have more parts than other types of microscopes like student and toy compound microscope
• Some laboratory microscopes have a binocular head
• They are primarily used in school laboratories

Research Microscope

Research microscopes are larger than regular microscopes and quite expensive. They are not portable and modular, with multiple filters and objectives attached to the body. It is among the most adaptable types of microscopes as more than one researcher uses it at one time. It is made for extensive research in scientific labs.

Characteristics and uses of Research Microscope:

• Larger than a regular laboratory microscope
• Not portable
• Expensive
• Multiple objectives and filters
• Used for research purposes in research laboratories

Student Microscope

Student microscopes are portable devices used to familiarize students with the structure and function of microscopes before hands-on experience with laboratory microscopes. They possess a 10x eyepiece to offer a magnification experience to the students. The lamp of student microscopes has LED or Hydrogen, whereas some are also battery-operated and more convenient to use in classrooms. Regular and student microscopes are made of metal and must not be confused with toy microscopes.

Characteristics and uses of Student Microscope

• Portable
• Use a Hydrogen or LED lamp, or battery-operated
• Made of metal like regular microscopes
• It helps familiarize students with microscope functioning

Toy Microscope

Toy microscopes are quite popular as they help develop the interest in science in young children. They are not the same as regular or student microscopes and are usually chosen for young children to learn by playing. These microscopes have numerous accessories that children can use to learn about microscopes and specimens. Toy microscopes have prepared slides, tweezers, plastic pipettes, etc.

They have a lower resolution as they are not meant to provide professional results. Their body may be made of metal or plastic with other components not made of the same material as a regular microscope. Toy microscopes are excellent for engaging young children interested in science and improving their cognitive skills.

Characteristics and uses of Toy Microscope:

• Not as high-quality as regular or student microscopes
• Comes with multiple accessories
• Best for young children

Phase-Contrast Microscope

A phase-contrast microscope is a type of optical microscope that works contrary to an electron microscope. It converts the phase shift in the light passing through a transparent specimen to a brightness change in the image.

Features

• Creates high-contrast images
•  Unstained cells can be viewed
• Live-cell imaging is possible
• An elevated version of the compound microscope

Parts

All the components of the phase-contrast microscope are the same as a light microscope except for the annular diaphragm and phase plate.

Annular diaphragm

The annular diaphragm is a circular disc having an annular groove. It is situated below the condenser lens. The light rays pass through this disc to the specimen.

Phase Plate

It is a transparent disc having a conjugate area. The conjugate area is basically either a negative phase plate (having a thick circular area) or a positive phase plate ( having a thin circular area)

Phase Contrast Microscope – Image formation

A tungsten-halogen lamp focuses partially coherent illumination through a collector lens onto the annulus. To obtain phase contrast, direct rays are separated from diffracted rays while they pass through the annular diaphragm. The wavefronts that pass through the annulus illuminate the object.

The object receives undeviated and diffracted light rays, then separated at the rear focal plane by the phase plate to form a phase-contrast image.

Uses of Phase Contract Microscope

The phase-contrast microscope produces high-contrast images of transparent specimens like micro-organisms, living cells, fires, thin tissue slices, etc. Cellular events, like cell division, can be viewed. Many biologists prefer using a phase contrast microscope because Unstained cells and cell organelles can also be seen.

Digital Microscope

A digital microscope is a variation of an optical microscope. It lacks an eyepiece and has a digital camera that forms an image of the specimen. The image is displayed on the LCD or monitor.

Features

• The digital camera magnifies the image
• The image is displayed on a monitor or LCD
• Magnification power depends upon the size of the monitor

Parts

Following are the parts of a digital microscope

The hardware

The hardware includes all the analog parts of a digital microscope. It consists of a light source and a camera.

The software

This part of the digital microscope includes camera drivers and image processing software.

Digital Microscope – Image Formation

The camera of the digital microscope works as an eyepiece. The light falls on the specimen, and the camera creates an image. The magnification of the image depends upon the size of the monitor.

The image viewer unit of the image processing software displays and saves the images. The brightness of the image can be adjusted using the image brightness adjustment unit of the image processing software.

Uses of Digital Microscope

These microscopes are widely used by students, researchers, and industrial employees. They save the cost of buying a microscope for every individual as a large magnified image is viewed on the big screen. This makes teaching and learning very easy.

Types of Digital Microscopes

Digital microscopes are used widely in modern research labs as they provide clear pictures on the digital screen and are easy to use. There are several types of digital microscopes including

Biological Digital Microscopes

They are usually used to examine specimens in biological research labs. Their high magnification and resolution with an objective lens of 4x to 100x make them a favourite choice. Biological digital microscopes have a light source under the stage that gives LED or Halogen illumination depending on the model.

Metallurgical Digital Microscopes

Metallurgical microscopes are more common in labs where wire circuits and other related metallic objects are studied. They are mainly constructed to observe metallic surfaces and opaque surfaces besides wire circuits.

Fluorescence Digital Microscopes

They are produced by changing the light source to phosphorescence or fluorescence in optical microscopes to create an image of the specimen. They are typically used for specimens that do not appreciate LED or Halogen.

Polarizing Digital Microscopes

These digital microscopes are used to observe and analyze 3D structures of anisotropic specimens with the help of polarized light to produce a digital video of high magnification.

Phase Digital Microscopes

Phase digital microscopes enable you to observe specimens without having to stain them. You can study live or dead organisms with this kind of digital microscope. They are either upright or inverted.

Inverted Digital Microscope

As the name says, these are inverted digital microscopes that have their objective lenses beneath the stage, and the light source is present on the top along with the condenser.

Handheld Digital Microscope

They are one of the most advanced digital microscopes embedded into a handheld microscope to observe forensics and surfaces.

Portable Digital Microscope

Portable digital microscopes are smaller than standard digital microscopes and are commonly used in medical studies to inspect the skin and medical surfaces.

USB Microscopes

USB digital microscopes connect to a computer system through a USB connector and have a permanently attached camera to observe the specimen.

Frequently Asked Questions

When was the first microscope invented?

The first Hans Martens/Zacharias Janssen was introduced as early as 1590, and they made a claim in 1655.

What is Galileo’s little eye?

Galileo’s little eye is a compound microscope with more than one lens. It enlarges the view of the specimen and allows the observer to examine the sample.

Are toy Microscopes Durable?

The durability of a toy microscope depends on your usage, care, and quality of the product. Toy microscopes are meant for fun learning for children and may break down soon if not handled with care. Children, less than three years of age should not be handed toy microscopes.

Which magnification should I use when using the microscope?

The magnification you use depends solely on the type of specimen you are analyzing and the results you want. However, if you are a newbie to microscopes, it is best to use the lowest magnification setting as it gives you a wide view of the slide, and you can focus better on what you want to study. New users are recommended to start at 4x and then increase magnification.

How to calculate the magnification of a microscope?

Calculating the magnification of a microscope is quite straightforward. To calculate the magnification, you need to know the magnification of the objective lens and eyepiece. Just multiply both magnification numbers to find the overall magnification of the microscope. Usually, the eyepiece is 10x, while the objective lenses vary between 4x, 10x, 40x, and 100x.

What are the common parts of Compound Microscopes?

Each of the four kinds of compound microscopes is different from each other depending on their functions and uses. However, their structure is somewhat similar. Whether you buy a toy microscope or a student microscope, they have a structure similar to regular microscopes. Common parts of compound microscopes include the body tube, nosepiece, objective lens, eyepiece, base, etc.

What is the field of view in a microscope?

The field of view is the slide area that you see through the eyepiece. Lower magnification enables you to see a wider area, while higher magnification means a smaller field of view. You can measure your microscope’s exact field of view by holding a ruler under the objective.

Are Research Microscopes expensive?

Research microscopes are the largest and most complicated compound microscopes suitable for group research. They are more expensive than regular microscopes, but you can find one for $500 or less.

What is the depth of view?

As the field of view is the diameter of the slide covered in the lens, the depth of field refers to the height or depth calculated as vertical distance in the specimen.

What are low-power and high-power microscopes?

Light microscopes are divided into two categories; low power and high power. Low-power microscopes are commonly called stereo microscopes as they are used to examine objects visible to the naked eye. Compound microscopes are high-power because they help observe cells that are not visible to the naked eye.

Should I choose a Halogen light source or LED?

The choice of a light source is highly dependent on your requirements and preferences. LED and halogen have their specific pros and cons for you to choose accordingly. LED light sources do not emit heat and last longer than halogen. But, sometimes, they give a specific yellow color to the specimen. On the other hand, halogen lights are similar to natural light; the bulbs are cheap but emit heat.

Can I see cells at 100x magnification?

If you wish to observe the cells of a specimen, you have to use a compound microscope at least with 400 magnification. It can also be obtained by choosing a 10x eyepiece and 40x objective lens to achieve the required magnification.

Are mechanical stages better than stage clips?

While the stage clips cannot move and are used to keep the specimen in one place, the mechanical stage allows you to move to observe the specimen in the direction you want. It moves in both X and Y dimensions to provide you with the perfect observation. If mechanical stages were not present, you would have to move the slide by hand around the stage clips to focus on the object.

Which microscopes are commonly used in school labs?

School laboratories usually have student microscopes or compound microscopes as they are not as expensive as research microscopes and are convenient for students to understand. The light source is beneath the stage, offering the students a clear view of the specimen. They can adjust the view of the specimen by moving the mechanical stage. Students use compound microscopes to study biological cells and other samples invisible to the naked eye.

Should I buy a student microscope with three lenses or four?

As student microscopes do not need to be as accurate and high quality as professional microscopes for students to understand the basics, they usually come with 3 objective lenses. These microscopes provide magnification of up to 400x with a 10x eyepiece.

Does an electron microscope examine living cells?

No. An electron microscope, such as scanning electron microscope (SEM), does not examine living cells as the bombardment of electrons kills them. So, researchers do not use these microscopes to study living cells.

Which microscopes are used to study blood cells?

If you wonder which type of microscope is used by technicians to study your blood samples, they typically observe samples through a scanning electron microscope with a magnification as high as 3,000,000x.

Can I take photos through a microscope?

While traditional microscopes do not offer to take a clear picture of the magnified image, modern digital microscopes can take images. They are attached to a computer via a USB cable. Some microscope models also allow you to attach a camera in place of the eyepiece to get a picture of the specimen. You can also connect a DSLR to the microscope for a high-quality image.

Conclusion

This article describes four different types of microscopes and their sub-types. These are the most frequently used and all of them have various features and are used for different purposes. So when choosing a microscope, keep in mind what your objective is and then select the right microscope in the budget that can be $100, $500, or above $1000