Microscope

All about microscope like working principle of microscope, types of microscope, mechanism, uses of microscope, handling of microscope, etc.

1. MICROSCOPE
PRESENTED BY:-
MD KAMIL
DEPT. OF FOOD SCIENCE AND TECHNOLOGY
MAKAUT, WEST BENGAL

2. CONTENTS
•INTRODUCTION
•TERMS AND DEFINITION
•TYPES OF MICROSCOPE
•PARTS OF THE MICROSCOPE
•WORKING PRINCIPLE
•MECHANISM
•CALCULATING MAGNIFICATION
•CARE OF THE MICROSCOPE
•RULES FOR USING MICROSCOPE

3. INTRODUCTION
The microscope is a valuable instrument. There are many
small objects or details of objects which cannot be seen by
the unaided human eye. The microscope magnifies the
image
of such objects thus making them visible to the human eye.
Microscopes are used to observe the shape of bacteria,
fungi, parasites and host cells in various stained and
unstained preparations.

4. TERMS AND DEFINITION
MICROSCOPE:-An instrument for viewing objects that are too small to be seen with the naked
or unaided eye.
MICROSCOPY:-The science of investigating small objects using such an instrument is called
microscopy.
PRINCIPLE:-Microscopy is to get a magnified image in which structures may be resolved which
could not be resolved with the help of an unaided eye.
MAGNIFICATION:-• It is the ratio of the size of an object seen under microscope to the actual
size observed with unaided eye.
• The total magnification of microscope is calculated by multiplying the
magnifying power of the objective lens to that of the eye piece.

5. TERMS AND DEFINITION
RESOLVING POWER:-
• It is the ability to differentiate the two close points as separate.
• The resolving power of an human eye is 0.25 mm.
• The light microscope can separate dots that are 0.25 µm apart.
• The electron microscope can separate dots that are 0.5 nm apart.
LIMIT OF RESOLVING:-
• It is the minimum distance between two points to identify them
separately
• It is calculated by Abbe’s equation :-

6. TERMS AND DEFINITION
• Resolving Power (R.P) = wavelength of light in nm / 2 x
numerical aperture of objective lens
• Limit of resolution is inversely proportional to power or
resolution.
• If the wavelength is shorter then the resolution is greater.
WORKING DISTANCE:-
• It is the distance between the objective and the objective slide.
• The working distance decreases with the increase in
magnification.

7. TYPES OF MICROSCOPE
Microscopes used in clinical practice are light microscopes. They are
called lightmicroscopesbecause they use a beam of light to view
specimens.
A compound light microscopeis the most common microscope used in
microbiology. It consists of two lens systems (combination of lenses) to
magnify the image. Each lens has a different magnifying power. A
compound light microscope with a single eye-piece is called monocular;
one with two eye-pieces is said to bebinocular.
ELECTRON MICROSCOPE :-Microscopes that use a beam of electrons
(instead of a beam of light) and electromagnets (instead of glass lenses)
for focusing are called electronmicroscopes. These microscopes provide a
higher magnification viruses used for observing extremely small
microorganisms such as viruses.

8. TYPES OF MICROSCOPE
(LIGHT MICROSCOPY)
BRIGHTFIELD MICROSCOPY:-
This is the commonly used type of microscope. In brightfield microscopy the field of view is
brightly lit so that organisms and other structures are visible against it because of their different
densities. It is mainly used with stained preparations. Differential staining may be used ending
on the properties of different structures and organisms.
DARKFIELD MICROSCOPY :-
In darkfield microscopy the field of view is dark and the organisms are illuminated. A special
condenser is used which causes light to reflect from the specimen at an angle. It is used for
observing bacteria such as treponemes (which cause syphilis) and leptospires (which cause
leptospirosis).

9. TYPES OF MICROSCOPE
PHASE-CONTRAST MICROSCOPY :-
Phase-contrast microscopy allows the
examination of live unstained organisms.
For phase contrast microscopy, special
condensers and objectives are used.
These alter the phase relationships of the
light passing through the object and that
passing around it.

10. TYPES OF MICROSCOPE
FLUORESCENCE MICROSCOPY : -
In fluorescence microscopy specimens are stained
with fluorochromes/ fluorochrome complexes.
Light of high energy or short wavelengths (from
halogen lamps or mercury vapour lamps) is then used
to excite molecules within the specimen or dye
molecules attached to it. These excited molecules
emit light of different wavelengths, often of brilliant
colours. Auramine differential staining for acid-fast
bacilli is one application of the ttechnique rapid
diagnostic kits have been developed using
fluorescent antibodies for identifying many pathogens.

11. COMPOUND MICROSCOPE
COMPOUND MICROSCOPE: -A microscope with a high
resolution and uses two sets of lenses providing a
2-dimensional image of the sample.
• The term compound refers to the usage of more than one lens
in the microscope. Also, the compound microscope is one
of the types of optical microscopes.
• It is said that the invention of the compound microscope is
done by the Dutch spectacles maker Zacharias Janssen in
early 1590.

12. COMPOUND MICROSCOPE
WORKING PRINCIPLE:-
•Acompoundmicroscopeisconsideredtobeoneofthestandardmicroscopesthatcanbeusedfor
generalpurposes.Thearrangementofthelensissuchthatitmagnifiestheobjectsfromthe
complexsystem.
Therearetwotypesoflensesthatareusedinthecompoundmicroscope:
i)Theobjectivelensisplacedclosetotheobjectthatneedstobeexamined.
ii)Theeyepieceallowstheimagetobeviewed.Theeyepieceisalsoknownastheocularlens.
•Thelightismadetopassthroughthethintransparentobject.Amagnifiedimageoftheobjectis
obtainedbytheobjectivelens.Thisimageisknownastherealimage.Theeyepieceortheocular
lensthenmagnifiestherealimagemoreandisviewedasthevirtualimage.

13. PARTS OF MICROSCOPE

14. PARTS OF MICROSCOPE
The compound microscope is mainly used for studying the structural details of cell, tissue, or
sections of organs.
The parts of a compound microscope can be classified into two:
• Non-optical parts
• Optical parts
(NON-OPTICAL PARTS )
BASE: The base is also known as the foot which is either U or horseshoe-shaped. It is a metallic
structure that supports the entire microscope.
PILLAR: The connection between the base and the arm are possible through the pillar.
ARM: The arm is also known as the limb which is a metallic handle forming the connection between
the arm to the inclined joint. The stage and the body tube is supported by the arm.

15. PARTS OF MICROSCOPE
INCLINATION JOINT : If the observation has to be done in a sitting position, then the microscope
can be tilted using the inclination joint.
STAGE : It is the metallic platform that is fitted to the lower part of the arm with a hole in the
center. The microscopic slides are placed on the stage either by using side clips or by
mechanical stage clips.
BODY TUBE : The main purpose of the body tube is to hold the objective and ocular lenses at the
two ends. The end where the ocular lens is present is known as the head while the end where
the objective lens is placed is known as the nose piece. For the passage of light rays through
the body tube, there is a pathway.
DRAW TUBE : The upper end of the body tube has a small fixed tube which is known as the
drawtube. The main function of the drawtube is to hold the ocular lens.
RACK AND PINION : To bring the object under focus, the rack and pinion are either attached to
the body tube or the stage.

16. PARTS OF MICROSCOPE
ADJUSTMENT SCREWS : These are two pairs of adjusting screws that are used either for a coarse
adjustment or for fine adjustment. When a fine adjustment is made, the body tube or the stage
moves extremely short distances while in coarse adjustment, the body tube and stage move
up. Through fine adjustment, a sharp image can be obtained.
AUTOMATIC STOP : The rack and pinion have a small screw that is used for stopping the
downward sliding of the body tube. This prevents damage to the objective lens.
(OPTICAL PARTS)
DIAPHRAGM : The amount of light falling on the object can be controlled through the
diaphragm. It is present below the stage. The disc and iris are the two types of diaphragm.
CONDENSER : It is present below the diaphragm. The focusing of light can be done by adjusting
the condenser by moving it either up or down.

17. PARTS OF MICROSCOPE
REFLECTOR : A reflector is a mirror that is attached above the base. One side of the mirror has a
plane mirror while the other side has a concave mirror. When the light is strong, the plane mirror
side is used and when the light is weak, the concave mirror side is used. The light on the object
is directed with the help of the reflector through the diaphragm and condenser.
OBJECTIVE LENSES : These lenses are present over the nose piece.
•There are two to three types of objective lenses:
1. Low power
2. High power
3. Oil immersion
The objective lens is a compound lens that forms a real inverted image of the image inside the
body tube.

18. PARTS OF MICROSCOPE
OCULAR LENS : The ocular lens is also known as the eyepiece. The image of microscopic objects can
be viewed through these lenses.
There are four types of magnification that can take place in the ocular lens:
• 5X
• 10X
• 15X
• 20X
Thebinocularheadisthedevicethatusestwoeyepiecesandhasmanymirrorsandprisms,which
makesthepassageoflighteasier.

19. WORKING PRINCIPLE
WORKING PRINCIPLE OF COMPOUND MICROSCOPE :
The compound microscopes are works on the principle that when a tiny specimen to be
magnified is placed just beyond the focus of its objective lens, a virtual, inverted and highly
magnified image of the object are formed at the least distance of distinct vision from the eye
held close to the eyepiece.

20. MECHANISM
MECHANISM OF COMPOUND MICROSCOPE :
Compound microscopes create an image of specimen by these following steps :
• First of all, a specimen is placed between the objective and condenser lens.
• Light emitted from the light source is pointed over the specimen with the help of a condenser lens.
• After that, the light is passed through the specimen and comes towards the objective lens.
• The objective lens captures the light coming from the specimen and creates a magnified image
of the specimen, which is called the primary image.
• Then the objective lens passed this image through the body tube to the ocular lens or eyepiece
and again magnifies the image.
• At last, the viewer can see a clear and magnified image of the specimen through the eyepiece.

21. CALCULATING MAGNIFICATION
To calculate the total
magnification of the compound
light microscope multiply the
magnification power of the
ocular lens by the power of the
objective lens. For instance, a
10x ocular and a 40x objective
would have a 400x total
magnification. The highest total
magnification for a compound
light microscope is 1000x.

22. CARE OF THE MICROSCOPE
Proper care and maintenance of the microscope should be done while using or after using.
TIPS FOR MICROSCOPE CARE :
• Handle with care.
• Keep lenses clear of slides.
• Clean after using immersion oil.
• Cover when not in use.
• Look after the bulb.
• Store in a clean, dry place.
• Only use special lens paper or wipes for cleaning the lenses.
• Keep your User’s Manual and wrenches in a safe place.

23. RULES FOR USING MICROSCOPE

24. THANKYOU