Microscope is made up off three basic component which include;
- Stand
The stand is the frame of the microscope, stand is skeleton of the microscope of which other part of the microscope is attached to.
- Mechanical component
The mechanical component of the microscope is used to adjust the microscope to the required standard during operation. They are sometimes called adjustment component. The component comprise of the following;
Stage adjustment
Course adjustment
Fine adjustment and
Condenser Adjustment
- The lens system
Now we are going to explain in details each of these component listed above.
The microscope stand
As we said earlier stand is the framework or the skeleton of the microscope, microscope stand comprise of the following;
The tube
Tube length
The body
The stage
The Tube
Tube are found on the upper part of the microscope before the eyepiece, it hold the objective lens and the eyepiece together tube is a connector that connect objective lens with the eyepiece. In almost laboratory microscope, three or more objective lens are required of which they are screw to revolving nose piece. The revolving nose piece help in rotating and change the objective lens for better focus when the microscope are put to use. Microscope are made up off different varieties of eyepiece, such as monocular, binocular, even tri or tetra ocular. But we will not go into details of that for now, we will only focus on binocular because it is the most used microscope in every laboratory. Microscope with two ocular lens is called binocular, these ocular lens is found on the apex part of the microscope, and it did not have screw, they are inserted into the tube. All lens of the microscope are very delicate as such it should be handle with care.
Tube Length
The distance between the eyepiece and the objective lens is called tube length.
The Body
The part of the microscope that provide or give support to the focusing mechanism is called the body
The arm
The part of the microscope that provide correct frame structure is called arms, the arm is the handle which hand is hold to lift the microscope up or move the microscope from one place to another.
The stage
Is like a rectangular shape, it provide space where object is placed. The stage is made up with circular whole in the center that allow the passage of light from the light source to get to the object. The stage have a mechanical part called mechanical stage, it help in moving the stage to different angle as such assist in moving the objet place on the stage to and flow.
The sub stage
After the stage we have subs stage, the sub stage help to hold condenser with its iris diaphragm and a holder for light filter.
The base
The base is sometime called footer is in the form of block or rectangular shape, is the foot of the microscope that touches the ground. It help the microscope to stand on a bench firmly.
MECHANICAL COMPONENT
As we mentioned earlier mechanical component is divided into; coarse adjustment, fine adjustment and condenser adjustment. Now we are going to look into details of the division of these component.
Coarse Adjustment
These is the part of the mechanical component of a microscope that is use for moving stage up and down. These component is control by stretching and a gear with a small number of teeth mechanism that is operated by a large knob attach to each side of the microscope. When these knob are rotated, the stage move up and down as such give rough focusing. These type of focusing is often sometime considered to be ok for low power objective lens.
Fine Adjustment
The fine adjustment is use for fine focusing, it help reveal the clear picture of the object under examination. These type of focusing is mainly use with high objective lens. The fine adjustment have two small knobs on both side of the microscope incorporated with the coarse adjustment in some microscope, while in some microscope it stand alone. When the knobs is rotated, it move the object up and down slow that it cannot be detected just ordinary looking.
Condenser adjustment
These adjustment possesses similar focussing, adjustment of aperture and centring. These have knob attach on the one side, when these knob is rotated, it move the condenser up and down. The condenser aperture also have adjustment part that help either open or close the aperture.
In term of centring the condenser, it depend on how they are fixed on the microscope. It only condenser that is not fixed permanently on the microscope that can be centred, centring of the condenser is by bring the illuminated beam of light to strike the object properly.
THE LENSE SYSTEM
Lens system of microscope is also called optic of the microscope it comprise all part of the microscope that are made up of lens. The part of the microscope that are made up of lens include; eyepiece, objective lens, condenser and light source, all of the mentioned are part of microscope that is made up of one or two lens and each have it various functional ability. Also sometime when electricity is not available, an external lens is apply in directing light from the external source to the microscope. Not even that, there are microscope build mostly the early microscope, they are built without inbuilt electric component, and the only source of their light is external light which is directed to the microscope via the external mirror.
Eyepiece
Eyepiece is the located on the top of the microscope, it often a place where the object under investigation is focus by eye. As we said earlier from the beginning of out discussion, eyepiece is made up of different type that is named depending on the number of the ocular lens. Example of the type of eyepiece include
Monocular one eye piece
Binocular two eyepiece
Trinocular three eyepiece
Tetranocular four eyepiece
Objective Lens
Objective lens help to produce and magnified image of the object under investigation. The light microscope are made up of three to four objective lens. These lens are screw to the revolving nose, the revolving nose help rotating the objective lens in circular part, of which the required objective lens can be selected and brought into the light part to view the object. Each of the objective lens is made up of complicated compound of lenses, the number of lenses which these objective lens is made up off determine it magnification power. The magnification of the objective lens are listed as follow;
Lower Objective Lens
These objective lens have lower number of lenses that they are made up of, and they can be identify as 10X or 16mm, or 2/3 inch. Or can be identified by their colour code assign to them. The code is yellow rings. These objective is mostly use for scanning the microscopic field.
High dry Objective Lens
These objective lens is identify by 40X or 4mm, or 1/6 inch. The colour code is a blue ring. These objective lens render higher magnification in dry objective lens.
Oil Immersion Objective Lens
These objective lens is used in conjunction with oil immersion, it have the highest magnification. It is identify as 100X or 2mm, or 1/12 inch. It often sometimes called dry Objective lens. It have white colour code ring.
Oil Immersion
These oil are cedar wool oil, it have the same optical density with that if glass. The oil is place in between the lens and the object, it help to eliminate light refraction as such give clear picture of the object under investigation.
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