There are several different types of microscopes. While the sole purpose of this greatest invention of science is magnification. 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.
So are you interested in finding out about 4 different types of microscopes, their features, advantages, and uses?
Keep on reading
Table of Contents
Kinds of Microscopes
Stereo Microscope
The stereo microscope is also known as a Dissecting microscope. It creates a 3-dimensional image of the object. It has two separate objective lenses and eyepiece, creating two separate optical paths.
This creates an image at slightly different angles in each eye.
Features
- Binocular
- 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 them 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.
Compound 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 eyepiece at the top and objective lenses at the bottom.
Nose piece
The nosepiece has a circular ring which 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 in a slide. It has stage clips to hold the slide in place.
Iris Diaphragm
Iris diaphragm is a circular opening in the stage through which light reaches the specimen.
Condenser
A condenser lens focuses the light rays on to 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 of the modern compound microscopes have an LED bulb to illuminate the object.
Base
The base provides stability to the compound microscope.
Phase-contrast Microscope
A phase-contrast microscope is a type of optical microscope that converts the phase shift in the light passing through a transparent specimen to brightness change in the image.
Characteristics
- 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. Conjugate area is basically either a negative phase plate (having a thick circular area) or 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 on to 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 illuminates the object.
The object receives undeviated and diffracted light rays, which are 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. 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 monitor.
Features
- Digital camera magnifies the image
- 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.
Conclusion
This article describes four different types of microscopes. 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.
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