The Microscope / Microscopy 🔬

The Microscope 🔬 :

A microscope is an instrument used to see objects that are too small to be seen by the naked eye. Microscopy is the science of investigating small objects and structures using such an instrument.

             The Compound Microscope 

When the microscope was invented around 1590, suddenly we saw a new world of living things in our water, in our food and under our nose. But it's unclear who invented the microscope. Some historians say it was Hans Lippershey, most famous for filing the first patent for a telescope.

In 1590 Two Dutch spectacle-makers and father-and-son team, Hans and Zacharias Janssen, create the first microscope. 1667: Robert Hooke's famous "Micrographia" is published, which outlines Hooke's various studies using the microscope.

Discovered By Antony Van Leeuwenhoek...

(Father of Microbiology)

Principle :

A general biological microscope mainly consists of an objective lens, ocular lens, lens tube, stage, and reflector. An object placed on the stage is magnified through the objective lens. When the target is focused, a magnified image can be observed through the ocular lens.

      Fig Show Various Parts Of Microscope

There are three basic, structural components of a compound microscope are the head, base and arm.

Head/Body houses the optical parts in the upper part of the microscope.

Base of the microscope supports the microscope and houses the illuminator.

Arm connects to the base and supports the microscope head.

1.Head – This is also known as the body, it carries the optical parts in the upper part of the microscope.

2.Base – It acts as microscopes support. It also carriers the microscopic illuminators.

3.Arms – This is the part connecting the base and to the head and the eyepiece tube to the base of the microscope. It gives support to microscope.

Eyepiece – also known as the ocular. this is the part used to look through the microscope. Its found at the top of the microscope. Its standard magnification is 10x with an optional eyepiece having magnifications from 5X – 30X.

Eyepiece tube – its the eyepiece holder. It carries the eyepiece just above the objective lens. In some microscopes such as the binoculars, the eyepiece tube is flexible and can be rotated for maximum visualization, for variance in distance. For monocular microscopes, they are none flexible.

✓Objective Lenses – These are the major lenses used for specimen visualization. They have a magnification power of 40x-100X. There are about 1-4 objective lenses placed on one microscope, in that some are rare facing and others face forward.  Each lens has its own magnification power.

✓Nose piece – also known as the revolving turret. It holds the objective lenses. It is movable hence it cal revolve the objective lenses depending on the magnification power of the lens.

The adhustabale to focus the microscope. There are two types of adjustment knobs i.e fine adjustment knobs and the coarse adjustment knobs.

Stage – This is the section on which the specimen is placed for viewing. They have stage clips hold the specimen slides in place. The most common stage is a mechanical stage, which allows the control of the slides by moving the slides using the mechanical knobs on the stage instead of moving it manually.

Aperture – This is a hole on the microscope stage, through which the transmitted light from the source reaches the stage.

Microscopic illuminator – This is the microscopes light source, located at the base. It is used instead of a mirror. it captures light from an external source of a low voltage of about 100v.

Condenser – These are lenses that are used to collect and focus light from the illuminator into the specimen. They are found under the stage next to the diaphragm of the microscope. They play a major role in ensuring clear sharp images are produced with a high magnification of 400X and above. 

The higher the magnification of the condenser, the more the image clarity. More sophisticated microscopes come with an Abbe condenser that has a high magnification of about 1000X.

Diaphragm –  its also known as the iris. Its found under the stage of the microscope and its primary role is to control the amount of light that reaches the specimen. Its an adjustable apparatus, hence controlling the light intensity and the size of the beam of light that gets to the specimen. For high-quality microscopes, the diaphragm comes attached with an Abbe condenser and combined they are able to control the light focus and light intensity that reaches the specimen.

Condenser focus knob – this is a knob that moves the condenser up or down thus controlling the focus of light on the specimen.

Abbe Condenser – this is a condenser specially designed on high-quality microscopes, which makes the condenser to be movable and allows very high magnification of above 400X. The high-quality microscopes normally have a high numerical aperture than that of the objective lenses.

The rack stop – It controls how far the stages should go preventing the objective lens from getting too close to the specimen slide which may damage the specimen. It is responsible for preventing the specimen slide from coming too far up and hit the objective lens. 

Courtesy : Microscope World