best microscope ppt prepared

8/10/2019 Best Microscope Ppt Prepared ...

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Microscope


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DEFINITION

- A microscope (Greek: micron= small and scopos= to look)

- MICROSCOPE:Is an instrument for viewing objects that

are too small to be seen by the naked eye- Microscope must accomplish three tasks:

*Magnification*Resolution

*Contrast


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MAGNIFICATION

Degree of enlargement

No of times the length, breadth or diameter, of an

object is multiplied.

Which of these images

would be viewed at ahigher power of

magnification?


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RESOLUTION

Ability to reveal closely adjacent structural

details as separate and distinct

LIMIT OF RESOLUTION (LR): The min distance between two visible bodies at

which they can be seen as separate and not in contact with each other

Types of microscope Resolving power

Compound Microscope 200 nanometers

Scanning Electron Microscope 10 nanometers

Transmission Electron Microscope 0.2 nanometers


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Contrast

- Giving the details visible to the eye, camera, or other imagingdevice


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HISTORICALBACKGROUND

2ndCentury BC: Ptolemy describes a stick that appears to bend in water


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1stCentury: Romans experiment with glass and observe objects larger whenviewed through glass

12thCentury: Salvino DArmante made first eye glass

1590: Hans Janssen and his son Zacharias Janssen,mount two lenses in atube to create first compound microscope


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1609: Galileo Galilee develops compound microscope with concave and convexlens

1665: Robert Hookes book Micrographia officially documents observationsthrough the microscope


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1674: Anton van Leeuwenhoek achieves greater magnification allowing him toobserve bacteria. Generally credited with bringing the microscope to the

attention of biologists.


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IS FIRST

Safety Biologica l co ntamination: Gloves

Grounded electrical connection (ideal)

Immersion oil in eyes

Location & Storage Do not use under vibration

Do not store in high humidity

Avoid intense temperatures

Keep clean


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Wear Personal Protective Equipment

Always check PPE for defects or tears before using If PPE becomes torn or defective remove it and replace with new

equipment

Do not reuse disposable equipment

Dispose of contaminated PPE properly

Wash hands immediately after removing PPE Treat all blood and bodily fluids as if they are contaminated

Wash thoroughly during cleanup and decontamination

Properly dispose of all contaminated material


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The following symbols are found on the microscope. Study the meaning of the symbols

and always use the equipment in the safest possible manner


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TYPES OF MICROSCOPE

- Simple microscope

- Compound microscope

- Electron Microscope

- Phase Contrast

Microscope

- Dark Ground Microscope

- Fluorescent Microscope

- Others


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SIMPLE MICROSCOPE


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More than five hundred years ago, simple glass magnifiers weredeveloped. These were convex lenses (thicker in the center than the

periphery). The specimen or object could be focused by use of the magnifier

placed between the object and the eye. These simple microscopes, alongwith the cornea and eye lens, could spread the image on the retina by

magnification through increasing the visual angle on the retina.

The image produced by such a magnifier, held close to the observers eye,appears as if it were on the same side of the lens as the object itself. Such an

image, seen as if it were ten inches from the eye, is known as a virtual image.

These magnifiers had severe limitations in specimen positioning, illumination,

lens aberrations, and construction.

Convex Lenses are curved glass used to make microscopes (and glasses etc.)

Convex Lenses bend light and focus it inone spot


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Simple magnifier. A simple magnifier uses a single lens system to enlarge the object in

one step


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COMPOUND

MICROSCOPE


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Around the beginning of the 1600s, through workattributed to the Janssen brothers in the Netherlands and

Galileo in Italy, the compound microscope was developed. Inits basic form, it consisted of two convex lenses aligned in

series: an object glass (objective) closer to the object or

specimen, and an eyepiece (ocular) closer to the observers

eyewith means of adjusting the position of the specimen

and the microscope lenses. The compound microscope

achieves a two-stage magnification. The objective projects a

magnified image into the body tube of the microscope and

the eyepiece further magnifies the image projected by the

objectiveFor example

The total visual magnification using a 10Xobjective and a 15Xeyepiece

is 150X


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Compound magnifier. In the compound microscope, the intermediate image formed by

the objective and tube lens is enlarged by the eyepiece.


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Parts of Microscope


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i. Optical component

ii.Mechanical componentiii.Electrical component


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Optical component

1. Its basic function is to gather the light passing through the specimenand then to project an accurate, real, inverted IMAGE of the specimen

up into the body of the microscope.

2. Other related functions of the objective are simply to magnified the

specimen with a given magnification rate i.e 4x,10x ,40x and 100x

magnification power

OBJECTIVE LENS


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Scan - 4X

Low Power - 10X

High Power - 40X

Oil immersion - 100X

TYPES
http://hjs.geol.uib.no/marinemicro/images/image70.gif


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OIL IMMERSION OBJECTIVE

- Highest magnification

- Oil prevents refraction of light outwards and

allows it to pass straight in to objective

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GLASS

OIL

A

B

C

D

E

G

F

FBEG - OILABCD - AIR


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Using the 100x immersion objective

1. Focus on the specimen using all objectives,

starting from the lowest-power to the

highest-power objective

2. Before engaging immersion objective, place

a drop of oil onto the specimen.3. Engage the immersion objective

Make sure oil is free of bubbles

4. Use the fine adjustment knob to bring the

specimen into focus

5. After use, remove oil from objective front

lens by wiping with gauze moistened with

70% alcohol


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Working distance

Objective

Magnification

Working

Distance4X 18.5

10X 10.6

40X 0.6

100X 0.13


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EYE PIECE

1. Its basic function is to look at the

focused, magnified real image

projected by the objective.

2. They are usually 10x,15x,40x and45x

- TYPES

(a) Monocular(Huygenian)

(b) Binocular (Ramsden)

(c) Trinocular (Compensating)
http://hjs.geol.uib.no/marinemicro/images/image71.gif


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Whats the power of this lens?

To calculate the power of magnification, multiply the power of the

ocular lens by the power of the objective, e..g.: 10x40=400 times

What are the powers of

magnification for eachof

the objectives we have

on our microscopes?

Fill in the table onyour worksheet.


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Comparing Powers of Magnification

Which of these images

would be viewed at a

higher power ofmagnification?

We can see better details with higher the powers of

magnification, but we cannot see as much of the image.

10x 40x


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.

SUBSTAGE CONDENSER

1. Its basic function is to gather the light coming from the light source and to

concentrate(focus) that light in a collection of parallel beams onto the

specimen.


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COLLECTOR LENS.

This lens is placed in front of the light source. Its function is to project an

image of the light source onto the plane of the condensers aperturediaphragm. In some instruments a diffusion or frosted filter is placed just

after the collector lens (side closer to the specimen) in order to provide

more even illumination.

FIRST SURFACE MIRROR

Its function is to reflect the light coming from the lamp up into the

substage condenser. Just before that mirror (closer to the lamp side)

is another variable diaphragm known as the field diaphragm


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TUBE LENS

Its function is to gather the parallel rays of light projected by the objective

and bring those rays to focus at the plane of the fixed diaphragm of the

eyepiece.

FILTERS -Blue, Green,

Heat absorbing filters,Barrier filters.


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ii. Mechanical component

Body TubeThe body tube holds the objective lenses

and the ocular lens at the proper distance

Diagram


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Nose Piece

The Nose Piece holds the objective lenses

and can be turned to increase the

magnification

Diagram


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Stage ClipsThese 2 clips hold the slide/specimen in

place on the stage.

Diagram


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CONDENSER HOLDER.

This holder receives any one of several types of condenser


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Diaphragm

The Diaphragm controls the amount of light

on the slide/specimen

Turn to let more light in or to

make dimmer.

Diagram


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Arm

Used to support the microscope when

carried. Holds the body tube, nose piece

and objective lenses

Diagram


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Stage

Supports the slide/specimen

Diagram


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Coarse Adjustment Knob

Moves the stage up and down (quickly) forfocusing your image

Diagram


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Fine Adjustment Knob

This knob moves the stage SLIGHTLY to

sharpen the image

Diagram


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Base

Supports the microscope

Diagram


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PARTS OF COMPOUND MICROSCOPE


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iii. Electrical component

ILLUMINATION -

Lamp, sunlight, battery

operated lamp, 60 W bulb,

Quartz halogen light.

It is light source

* step-down transformer

* switch* Rheostat

* lamp (halogen or incandescent)

* fuse

* Electronic sub system


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Light Source

Projects light upwards through thediaphragm, the specimen and the lenses

Some have lights, others have mirrorswhere you must move the mirror to reflect

light

Diagram

Operational Principle


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Operational Principle

Light

Knowledge of the behavior of light and the effects resulting when light passes from

air through a glass convex lens and out into air again is fundamental to the

understanding of image formation. When light passes from air into a convex lens,

the speed of light is slowed. The various colors, differing in wave length, are slowed

at different rates (dispersion). This bending (refraction) effect differs for different

colors. Those rays which strike the central area of the lens at a perpendicular

emerge unrefracted. Light passing through the other parts of the convex lens are

refracted or bent. The blue rays are bent more than thegreen rays, more than

the red rays.

When white light passes through convex lenses of objectives, eyepieces, or

condensers, two main kinds of aberrations may occur; chromatic aberration and/or

spherical aberration. These aberrations can be corrected in the design of the

lenses.0


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nstallation and commission


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DETAILED OBSERVATION PROCEDURE


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DETAILED OBSERVATION PROCEDURE


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General Maintenance


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Preventive Maintenance

Daily Preventative Maintenance

Objective (after using oil immersion lens)

Body

Yearly Preventative Maintenance

Microscope frame

Observation Tubeoptical axis

Observation Tubeleft/right axis

Observation Tuberevolving axis

Observation Tubeparfocality

As needed Grease replacement parts

General Maintenance


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General Maintenance

General Maintenance


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General Maintenance

General Maintenance


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Cleaning the eyepieces

Never rub the lens surface strongly

Do not use the same lens tissue to clean more than one lens

Do not moisten lens tissue with excessive amounts of cleaning solution

When cleaning with tweezers, be careful not to protrude its tip from the lens tissue

General Maintenance


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General Maintenance -

Cleaning the Objective Lens

*When cleaning oil immersion objective, first wipe objective with a dry lens tissue

General Maintenance


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General Maintenance


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General Maintenance


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Preparing for Inspection

General Maintenance


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Inspection Sheet

Use the CX21 inspection sheet

and check the electrical unit,

mechanical and optical

performance

General Maintenance


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Inspection: Checking for Dust

Close aperture iris diaphragm

When aperture iris diaphragm is closed

the depth of focus increases and the dirt

position is brought into focus

Observe a specimen through the

eyepiece

Image influence caused by dirt on each component

General Maintenance


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General Maintenance

Inspection: Checking for Dust

Note: If dirty portion

can not be

identified, it is

assume that the

internal lens andprism are

contaminated.

General Maintenance


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General Maintenance

Inspection: Checking Lenses

General Maintenance


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General Maintenance

Inspection: Checking Lenses

General Maintenance:


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Checking Left/Right Alignment Place the cross eyepiece into the right

sleeve

Place a slide with an image with a

recognizable reference point (e.g. center

of a spiral), secure it on stage

Align the reference point in the center of

the cross of the eyepiece (looking

through right eyepiece) by moving the

stage with the control knob



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Checking Left/Right Alignment

Cont.



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Checking Left/Right Alignment

Cont.



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Checking Left/Right Alignment Switch the cross eyepiece to the left

sieve

If the crosshair is aligned with the same

reference point, the left/right alignment iscorrect

If the crosshair is not aligned, do NOT move

the stage. The left eyepiece sleeve needsadjusted.

General Maintenance: Fixing


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Left/Right Alignment



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Left/Right Alignment



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Left/Right Alignment2`------------

---

Common Failures


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Electrical/Power Failure Light does not turn on when power switch is turned on

Light bulb burnt out

Objective not placed in alignment

Dirty components

Eyepiece

Objectives

Filters

General User Error

Not in focus

Brightness not adjusted properly

Objective not rotated fully into secured position

T bl h ti


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Troubleshooting

What is troubleshooting?

A logical, systematic process that is able to determine "what" happened, "why" ithappened and a method to develop effective fixes for the "why" it happened.

Why do we Troubleshoot?

To prevent the equipment and machinery from repeat incidents and failures

5 St f T bl h ti


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5 Steps of Troubleshooting

oPreparation

oStep 1 Observation

oStep 2 Define Problem Area

oStep 3 Identify Possible CausesoStep 4 Determine Most Probable Cause

oStep 5 Test and Repair

oFollow-up

Preparation


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Preparation

oBefore you begin to troubleshoot any piece ofequipment, you must be familiar with safety rules andprocedures for working on electrical equipment.

Be Safe!

Turn off power, ground yourself, and use gloves when

appropriate

oNext, gather information regarding the equipment andthe problem.

Be sure you understand how the equipment is designed to

operate it.Operation or equipment manuals and drawings are great

sources of information and are helpful to have available.

If there are equipment history records, you should review

them to see if there are any reoccurring problems


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Step 1: Observation

oWhat Happened?oMost faults provide obvious clues as to their cause.

oThrough careful observation and a little bit of reasoning,most faults can be identified as to the actual componentwith very little testing.

oWhen observing malfunctioning equipment, look forvisual signs of mechanical damage such as indications

of impact, chafed wires, loose components or parts lying

in the bottom of the cabinet.

oLook for signs of overheating, especially on wiring, relay

coils, and printed circuit boards

oDo not forget to use your other senses


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when inspecting equipment.

The smell of burnt insulation is something you would not

miss. Listening to the sound of the equipment operating may

give you a clue to where the problem is located.

Checking the temperature of components can also help

find problems, but be careful while doing this, some

components may be alive or hot enough to burn you.

oPay particular attention to areas that wereidentified either by past history or by the person that

reported the problem.


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Here is a note of caution! Do not let these mislead you, pastproblems are just thatpast problems, they are not

necessarily the problem you are looking for now.

Also, do not take reported problems as a fact, always checkfor yourself if possible. The person reporting the problem

may not have described it properly or may have made their

own incorrect assumptions.

Step 2: Define the Problem Area


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Step 2: Define the Problem Area

oAt this stage you apply logic and reasoning to yourobservations to determine the problem area of the malfunctioning

equipment.

Often times when equipment malfunctions, certain parts of

the equipment will work properly while others not.

oThe key is to use your observations (from step 1) to rule outparts of the equipment or circuitry that are operating properly and

not contributing to the cause of the malfunction. You should continue to do this until you are left with only the

part(s). If faulty, it could cause the symptoms that the

equipment is experiencing.

o To help you define the problem area you should have a


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oTo help you define the problem area you should have aschematic diagram of the circuit, in addition to your noted

observations.

oStarting with the whole circuit as the problem area, take eachnoted observation and ask yourself, "what does this tell me about

the circuit operation?".

If an observation indicates that a section of the circuitappears to be operating properly, you can then eliminate it

from the problem area.

As you eliminate each part of the circuit from the problem

area, make sure to identify them on your schematic. This will help you keep track of all your information.

Step 3: Identify Possible Causes


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Step 3: Identify Possible Causes

oOnce the problem area(s) have been defined, it is necessaryto identify all the possible causes of the malfunction.

This typically involves every component in the problem

area(s).

oIt is necessary to list (write down) every fault which couldcause the problem no matter how remote the possibility of itoccurring.

Use your initial observations to help you do this.

During the next step you will eliminatethose which are

not likely to happen.

Step 4 Determine the Most Probably


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Step 4 Determine the Most Probably

Cause

oOnce the list of possible causes has been made, it is thennecessary to prioritize each item as to the probability of it being the

cause of the malfunction.

The following are some rules of thumb when prioritizing

possible causes.

Although, it may seem to be possible for two components to

fail at the same time, it is not very likely. Start by looking for

one faulty component as the culprit.

oThe following list shows the order in which you should check


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components based on the probability of them being defective:

1.Components that burn out or have a tendency to wear out: i.e.

mechanical switches, fuses , relay contacts, and light bulbs.(Remember, fuses burn out for a reason. You should find out why

before replacing them.)

2.Coils, motors, transformers, and other devices with windings:

These usually generate heat and with time, can malfunction.3.Connections: especially screw or bolted type. Over time these

can loosen and cause a high resistance. In some cases this

resistance will cause overheating and eventually will burn open.

Connections on equipment that is subject to vibration, are

especially prone to coming loose.4.Defective wiring: Pay particular attention to areas where the

wire insulation could be damaged causing short circuits. Do not

rule out incorrect wiring, especially on a new piece of equipment.

Step 5 Test and Repair


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p p

oOnce you have determined the mostprobable cause, you must either prove it to bethe problem or rule it outby

inspection/observation or by using test

instruments

oTest Instruments: used to helpnarrow the problem area and

identify the problem component.

specialized instruments designed

to measure various behaviors ofspecific equipment

General instruments (i.e. multimeters)

oImportant Rule: when taking meter readings, predict what the


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meter will read before taking the reading.

Use the circuit schematic to determine what the meter will

read if the circuit is operating normally.If the reading is anything other than your predicted value, you

know that this part of the circuit is being affected by the fault.

oDepending on the circuit and type of fault, the problem areaas defined by your observations, can include a large area of the

circuit. It creates a very large list of possible and probable

causes.

Use a divide and eliminate approach to eliminate parts of the

circuit from the problem area.The results of each test provides information to help you

reduce the size of the problem area, until the defective

component is identified.


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oOnce you have determined the cause of the faulty operation

of the circuit, replace the defective component.

oAfter replacing the component, you must test operate allfeatures of the circuit, to be sure you have replaced the

proper component and that there are no other faults in

the circuit.

It can be very embarrassing to tell the customer that youhave repaired the problem only to have him find another

problem with the equipment just after you leave.

Follow-UpNot an official step of the troubleshooting process but it


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Not an official step of the troubleshooting process, but it

should be done once the equipment has been repaired and

put back in service.

oTry to determine the reason for the malfunction. Did the component fail due to age?

Did the environment the equipment operates in cause

excessive corrosion? Are there wear points that caused the wiring to short out?

Did it fail due to improper use?

Is there a design flaw that causes the same component to

fail repeatedly?

oThrough this process further failures can be minimized.

oMany organizations have their own follow-up documentationand processes

o If you determine there was human performance (or user


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y p (

error) involved in the equipment issue, the troubleshooter

needs to step out of the equipment analysis role and

interview people who have interacted with the equipment or

machinery in question.

o May need to properly train users on equipment usage.

Troubleshooting


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Troubleshooting


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Troubleshooting

Electrical Unit

If lamp does not turn on when power switch

is turned on, there is a problem with the

electrical unit, unless

Troubleshooting


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Electrical Unit

After verifying the light bulb is not the issue,

check that the microscope is plugged in and

that outlet has power(use another deviceyou know to be working to validate this)

Verify the chord shows no obvious damage

Verify the fuse is intact

Troubleshooting


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If the previous steps revealed no culprit

The problem is most likely the circuit board

itselfReplacing individual components is not feasible,

entire board needs replaced

If an identical microscope exists that is not

usable for another reason, harvesting its circuitboard is an option. See the manual for

instructions on removing the circuit board

Troubleshooting


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g

Coarse/Fine adjustment knobs do not

turn smoothly

New grease needs applied to knobs

If using a different microscope, turn to

manual for knob-removal instructions

Instructions for CX-21 provided next

Troubleshooting:Focus Knobs


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g

Dissassemble fine

adjustment knob

assembly (A) and fine

adjustment knob(B) by

turning them in arrow

directions

Remove the spring

washer (C) and washer

(D)

Remove the fine shaft

mount (E) with a

spanner (wrench) whileholding the coarse

adjustment knob (F)

Troubleshooting: Focus Knobs


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Remove the coarse adj.

knob (G) by turning it

counterclockwise while

holding the coarse adj.

knob (F).

Remove the tension

knob (H) by turning it

counterclockwise.

(The washer (I) is

attached to tension

knob (H) with grease.)

Troubleshooting: Focus Knobs


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Pull out the tension

ring (J) while holding

the convex part using

pliers

Place grease wherever

indicated in figure

Reassemble them in

the reverse order

Troubleshooting


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Stage falls down spontaneously or an in-

focus image quickly moves out of focus

Cause: tension on coarse adjustment knob

is too loose, needs to be adjusted

Troubleshooting:Coarse Knob Tension


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On the CX-21, the tension of the

coarse adjustment knob can be

adjusted by inserting a flat head

screwdriver into (2). Rotating

clockwise increases tension,

rotating counterclockwise

reduces tension

If the stage is falling on its own,

increase the tension.

If the knob is hard to turn and

grease has already been

applied, reduce the tensionslightly

Troubleshooting: Stage Movement


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If the stage does not move smoothly in

the X or Y directions, the tension of the

X/Y wires must be adjusted

Instructions for CX-21 are provided in

following slides, for other models see

manual

roubleshooting: Stage Movement


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Troubleshooting:Stage Movement


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X-tension adjustment

Troubleshooting:Stage Movement


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g g Y-tension adjustment

Troubleshooting:Backlash


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CARE OF THE MICROSCOPE


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- Handling

- Proper storage

- Care of Lenses

- Care of mechanical part

- Care of electrical part and lamp

are and maintenance of your microscope


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The microscope has 3 major enemies:

1. Dust

Protect the microscope from dust- make sure you use a dust

cover.

NEVER CLEAN THE OPTICS WITH A DRY TISSUE /SWAB/ COTTON BUD OR YOUR SHIRT SLEEVE! This willscratch the lens and cause irreparable damage. This isbecause the lens is usually coated with an anti-glare layer(bluish in colour). Try to remove dust from the optics byblowing gently on them, or use an air blower.

SOLUTION: make sure you use a dust cover when themicroscope is not in use or is being stored.


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Source: www.funsci.com/fun3_en/dust/dust.htm

usty microscope image

2. Humidity
http://www.funsci.com/fun3_en/dust/dust.htmhttp://www.funsci.com/fun3_en/dust/dust.htm


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Humidity (warm and wet) offers the perfect environment forfungus to grow.

Fungal growth will occur primarily on the optics of themicroscope. Once you have a fungal infection on yourmicroscope it is difficult to remove and may permanentlydamage your optics.

Using a plastic dust jacket (like the one supplied with thescope) is a bad idea.

SOLUTION: Buy some thick calico and use the plastic cover as a

template to make dust covers that are washable and canbreathe. This prevents condensation inside the cover and thedevelopment of ideal conditions for fungal growth (warm andwet)

3. Water


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Microscopes are electrical items. Water

and electricity are a dangerous mix!

Storing your microscope when it is wet

may lead to corrosion of parts and hygiene

problems. See also enemy number 2! If wet mounts are used, the stage is to be

cleaned and dried before returning the

scope to storage. The optics must be kept

dry to prevent fungal attack.

Summary


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y

Safety is the first priority: microscopes are used to

examine biological specimens, gloves are imperative

Microscopes have many moving parts which must be

properly positioned for clear viewing

Always check that the microscope is being used

properly before assuming there is another problem

Dirt and dust can reduce image quality, when trying to

deduce debris location

best microscope ppt prepared

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