Microscopy is a technique used to visualize structures or objects of very minute magnification.
For this instruments named as microscopes are used to magnify the images.
The invention of microscopes has revolutionized science, medicine, and other areas where microscopic structural examination is required for betterment.
It was possible to identify microbes like bacteria, fungi, protozoans etc. which are the causes of epidemic disease.
With advancement of technology, one is able to even get an image of virus and even minute molecular structures.
Besides, it is possible to take image of tissues and even label the specimens pictures by connecting them to computers.
Currently microscope find their use in biology, medicine and even research.
Types of microscope
Simple microscope: This is a just microscope with a single magnification lens like 10x.
It is used to visualize any small objects which are so minute and not clearly visible to naked eye.
Stereoscopic dissecting microscope: This microscope is commonly used to study and to identify the opaque objects. It is generally used for low power observation, dissection, etc. Its magnifying power varies from 4x to 40x or even 60x. It has two objectives and two eyepieces which help to make a 3D image of an object.
Compound microscope: Compound microscope is the most commonly used microscope used in labs performing biological experiments and clinical diagnosis.
It has and eye piece and 2 or 3 objectives lenses. The magnification power ranges from 5x to 8x, 10x to 15 x with the magnification of the objectives that ranges between 10x or 40x. It is used to examine semitransparent and translucent objects, or part of objects in the form of thin slides. Most bacteria, protozoa, blood cells can be observed by using it.
Phase contrast microscope: Phase contrast microscope is commonly used to study biological tissues and specimens. It is also known as one of the most important tool in medical research. It is generally used to study the specimens that are colorless and transparent and usually difficult to distinguish from their surroundings. These specimens or objects are commonly termed as phase objects. All phase contrast microscope are not same but, they work on the same principle and have five eyepieces of different magnification that includes 10x, 20x, 40x, 100x and Bright Field (BF).
The electron microscope: This is ultimate microscope to study any know minute particle. It is used to study a variety of biological and non-biological products such as cell organelles, DNA, RNA, enzyme structures, virus, biopsy sample, metals, crystals and large molecules. It is one of the important tools for biological and medical sciences as it magnifies the image of an object by 10,000,000x. Unlike other types, here one does not see the object under study with naked eye. The instrument produces images of the objects under study and one needs to observe the images. In electron microscope two types of lenses are present like “electrostatic” and “electromagnetic”. These types help to control the beam of electron which helps to illuminates the specimen and produces its magnified image.
Electron microscope is of five different types:
1. Transmission electron microscope (TEM) 2. Scanning electron microscope
3. Reflection electron microscope 4. Scanning transmission electron microscope
5. Low-voltage electron microscope.
Electron microscope is very expensive and requires a separate chamber for its housing. besides one need to have a nitrogen plant for use during operation as it generates large amount of heat.