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OPTICAL COMPONENTS
There are two optical systems in a compound microscope: Eyepiece Lenses and Objective
Lenses:
Eyepiece
or Ocular is what you look through at the top of the microscope. Typically, standard
eyepieces have a magnifying power of 10x. Optional eyepieces of varying powers are available,
typically from 5x-30x.
Eyepiece tube
holds the eyepieces in place above the
objective lens
. Binocular microscope heads
typically incorporate a diopter adjustment ring that allows for the possible inconsistencies of our
eyesight in one or both eyes. The
monocular (single eye usage) microscope
does not need a
diopter. Binocular microscopes also swivel (
Interpupillary Adjustment
) to allow for different
distances between the eyes of different individuals.
Objective Lenses
are the primary optical lenses on a microscope. They range from 4x-100x and
typically, include, three, four or five on lens on most microscopes. Objectives can be forward or
rear-facing.
Nosepiece
houses the objectives. The objectives are exposed and are mounted on a
rotating turret
so that different objectives can be conveniently selected. Standard objectives include 4x, 10x,
40x and 100x although different power objectives are available.
Coarse
and
Fine Focus
knobs
are used to focus the microscope. Increasingly, they are
coaxial
knobs
- that is to say they are built on the same axis with the fine focus knob on the outside.
Coaxial focus knobs are more convenient since the viewer does not have to grope for a different
knob.
Stage
is where the specimen to be viewed is placed. A mechanical stage is used when working at
higher magnifications where delicate movements of the specimen slide are required.
Stage Clips
are used when there is no mechanical stage. The viewer is required to move the slide
manually to view different sections of the specimen.