the components of a microscope

THE COMPONENTS OF A MICROSCOPE

Saleha MurtazaMLT-2nd Year

The microscope have two types of components

Optical Components Non-optical components

OPTICAL COMPONENTS Are the components through

which light can pass through.

Light sourceCondensersObjectivesEye PieceBody Tube

Non-optical Components : Are the components through which light

can not pass through.

StageBaseCoarse and Fine adjustmentsRevolving Nose

LIGHT SOURCE: Two types of lenses are used: Oil Lamps Low Voltage Electric Lamps In ancient times sun light was the basic

light source These lamps operate via transformer and can be adjusted to

the intensity required.

CONDENSER: As light from the lamp is stray out and is

in horizontal path so Main purpose of condenser is to focus or

concentrate the light into the plan of the object

With in the limits the more the light at the specimen the more will be the resolution power.

Condensers are provided with adjusting screws for centering the light path.

APERTURE DIAPHRAGM a part of condenser which control the

diameter of light beam.

<aperture______increse contrast >aperture______decrease contrast

CONDENSER

OBJECT STAGE:

Above the condenser is the object stage which is a rigid platform with an aperture through which the light cam pass.

It supports the glass slide and grip it with clips.

It can be moved vertically and hrizontally to view the slide from each n every side.

STAGE

OBJECTIVES: 9 to 15 pieces of elements are present in

OL. Forms real image

Types:

Four types of objective lenses are used

A-chromates Apo-chromates

Plane chromates Fluorites

A-chromates

Most commonly used Chromatic aberrations are corrected. Focuses blue and red light on the point of

focus.

Apo-chromates: Highly corrected and the most expensive

lenses. No spherical and chromatic aberrations. Made up of a variety of elements and

minerals.

Plane chromates:

No spherical aberrations. Plane of view field is perfectly flat from

edges. Suitable for photomicrography.

Fluorites:

No spherical aberrations. Subtle differences in specimen colour are

present.

Numerical Aperture: NA=n*sin u

n----> refractive index of medium between OL and Ray R

Sin u----> angle between principle axis and outer most ray.

Un-obtainable condition is when Sin 90 when refractive index will be 1.

NOSEPIECE:

Objectives are screwed in a revolving nosepiece through which they are changeable .

Body tube:

Three types are available

Mononuclear Binocular Combined photo binocular

MONONOCULER BINOCULER CMBINED PHOTOBINOCULER

Eyepiece:

Magnifies the image formed by the OL within the body tube.

Present eye with Virtual image. Eyepiece with high focal lengths are

formed for the people using spectacles.