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C D
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K L
M N
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Q R
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U V
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Y Z
A
Aberration
- An optical defect. The lens does not bring all the rays
of light to an exact focus. There are several different types
of aberrations each having a contributing factor on image
quality.
Achromatic
- Color corrected optics used to produce true color.
Achromatic Condenser
- A condenser corrected for spherical aberration. It is the
most common type found on brightfield microscopes.
Achromatic Lens
- A lens system that has been corrected to provide the same
focal length for the red and blue wavelengths of light. The
result is an image virtually free of extraneous coloring or
aberrations.
Alignment
- A condition in which all optical elements are centered on
the same axis.
Analyzer - The part of a polarizing system that can select
one angle of light and is used in conjunction with a polarizing
filter.
Aperture
- A fixed or adjustable opening or hole through which light
may pass through.
Apochromat
- A lens system in which chromatic aberration is corrected
for three or more colors.
Apochromatic Lens - An apochromatic lens system can
correct for three colors instead of two. This type of lens
also has less spherical aberrations.
Arm
- The part that serves as both the support of the body tube
and its lens systems. The part held when the microscope is
carried. Also sometimes referred to as limb
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B
Base
- The weighted bottom portion of the microscope which gives
it both balance and resistance to unexpected movement or vibration.
Beamsplitter - A device that allows light to be split
into two paths usually comprised of a piece of glass with
special coatings mounted at a 45 degree angle from the input
source.
Binocular - A microscope head that has an eyetube for
each eye.
Brightfield
– An illumination method in which light is reflected
off the specimen and passed through the objective to the eyepieces.
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C
CCD-Charged Coupled Device.
This is the image detector or chip inside a video camera.
CCD's are categorized by their diagonal size like 1/3",
1/2", 2/3", etc.
Chromatic Aberration
- An optical defect of a lens characterized as color fringes
or halos. They are caused by different wavelengths of light
focusing at different distances from the lens.
Coarse Adjustment
- The control knob which moves the specimen (or objective)
rapidly allowing focusing to occur.
Color Temperature
- The quantitative value indicating the amount of color or
colors emitted by an object measured in Kelvins.
Condenser
- The lens system between the illuminator and the specimen
which condenses the light onto the specimen.
Contrast
- The ratio of light and dark. To produce a good image, you
must have good contrast as well as good resolving power.
Corrected Lens
- A lens or lens system which corrects for specific aberrations.
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D
Darkfield
- An illumination method used to examine specimens which cannot
be distinguished from the background. Components include a
dry darkfield condenser for low magnifications and any low
magnification objectives. An oil darkfield condenser is used
for higher magnifications. Higher magnification oil objectives
must have an iris.
Daylight Filter
- A blue colored filter used to correct the color temperature
of a light source.
Depth of Field - A short distance along the optical axis
throughout which the specimen can be seen with sufficient
clarity.
Depth
of Focus
- A
short distance along the optical axis throughout which the
specimen image is focused sharply.
DIN
- Deutch Industrie Normen - An international standard used
in the manufacture of interchangeable objective lenses.
Disc Diaphragm
- A fixed rotary disk, located under the stage of a student
grade microscope, that has graded openings that allow various
angles of light to come up through the stage opening. Also
available as a continuously varying diameter (like a camera
shutter) adjusted by a lever located on the side of the component.
Drawing Tube (Camera Lucida)
- This device enables a person to view the specimen and a
paper and pencil simultaneously for drawing superimposed.
Dual Viewing Attachment
- Enables two people to view the same specimen through the
same microscope simultaneously.
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E
Empty Magnification
- Described as magnification which increases the size, but
does not increase the detail, due to the limitation of the
resolving power of the optical system.
Eyepiece
- The lens system closest to the eye. Also referred to as
"oculars".
Eyepiece tube
- Tubes of the microscope head which hold the eyepiece.
Eye
Point
- The location or position of the eye which allows for the
best possible viewing of the image.
Eye
relief
- The distance from the vertex of the eyepiece lens to the
users eye at the eyepoint.
Exit
Pupil - Exit pupil describes the image that is projected
to a particular point in space beyond the eyepiece. Your eye
must be positioned in that exact location in order to see
the full, clearly focused image. The exit pupil is a dimension
usually expressed in millimeters.
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F
Fluorescence
- An illumination method used to locate fluorescently tagged
material (protein, enzyme, and gene) by exciting the material
with one wavelength of light in hopes that the fluorescence
will appear by emitting a light at a different wavelength.
Fluorite
- An objective corrected for two wavelengths and therefore,
with a higher resolving power than an Achromat. There are
exceptions as some manufacturers call them Fluor, Neo-Fluor,
Fluotar and others.
Field
- Field is the diameter of the viewing area, usually expressed
in millimeters. As magnifying power is increased, the field
of view is decreased.
Filter
- A colored transparent material placed in the path of illumination
to vary the conditions of viewing.
Filter mount
- An existing slot on the microscope which can hold filters
in the path of illumination.
Filar eyepiece - An eyepiece with an integrated measuring
reticle and a moveable cross hair for making measurements
on a microscope.
Fine Adjustment
- The control knob which moves the specimen (or objective)
very slowly allowing microtonal focusing to occur.
Finity
Correction System
-
Finity Correction System is an optical system
whereby the image formed is made solely by an objective lens.
Flatness of Field - A quality describing the appearance
of the field of view as being flat from edge-to-edge.
Focal
Length
- The distance from a point where an image is formed to a
point in the lens system as shown in the drawing at right
labeled "FL".
Focal Point - A point in which light rays converge after
passing through a lens as shown in the drawing at right labeled
"FP".
Focus Rack
– The part of the microscope which allows the distance
from the objective lens to the specimen to vary and to accomplish
coarse and fine focus adjustments.
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H
Huygenian Eyepiece
- An eyepiece with correction for chromatic difference of
magnification in the achromatic objective lens.
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I
Illumination
- The application of light onto an object or specimen under
a microscope.
Illuminator
- The source of light which illuminates the object or specimen
to be observed. It may have fixed intensity or variable intensity
via a control knob.
Incline
- Eyepiece tubes are manufactured at an angle (30-45 degrees)
to allow more comfortable posture during long periods
of observation.
Infinity
Correction System - Infinity
Correction System is an optical system by
which the image is formed by an objective lens and a tube
lens working in tandem.
Interchangeable Eyepieces
- This simply means that the microscope eyepieces are removable
and can be exchanged with higher or lower powered eyepieces.
Interchangeable Objective
- An objective that is either threaded into a nosepiece turret
or mounted on a dovetail that is removable and that can be
replaced by another objective with a different magnification
power.
Iris
diaphragm - A device which can open and close like the
iris of an eye.
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J
JIS
- Japanese Industrial Standard
- An international standard used in the manufacture of interchangeable
objective lenses. A Typical JIS type microscope utilizes 36mm
objectives and a 170mm tube length for a 206mm system.
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K
Koehler Illumination - Koehler
illumination was introduced in 1893 by August Köhler as a
method of providing the optimum specimen illumination.
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L
Lens
- An optical grade glass which has two polished surfaces and
is used to converge or diverge light rays.
Light
- Electromagnetic radiation consisting of photons.
Long
Working Distance
- Refers usually to an objective or a microscope with a greater
than normal working distance.
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M
Magnification
- The enlargement of an object by an optical instrument.
Magnifying Power
- The metric of a lens or combination of lenses to make an
object appear larger is called magnifying power. It is the
number of times the image is larger than the object would
appear to the unaided eye.
Micro-manipulator
- Is used to inject or extract substances from a specimen.
Also used to measure or apply electric current to a specimen.
Microscope
- A high precision optical instrument which uses light to
observe objects. It is capable of high magnification and resolution
and is used for making minute details visible.
Monocular - A microscope head with a single eyepiece.
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N
N.A. - Numerical
Aperture. N.A
is a combination of resolving power, focal depth, and luminosity
of the image. The larger the N.A. value, the higher
the resolving power and the smaller the focal depth.
Nosepiece
- A rotary turret mounting for a set of objectives.
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O
Objective Lens
- The compound lens system in a microscope which receives
light from the field of view and forms the primary image.
The lens system closest to the specimen is the objective lens.
Ocular Micrometer
- When an ocular micrometer is inserted in the eyepiece, it
enables the person to take measurements of a specimen. It
is also known as eyepiece micrometer.
Oil
Immersion
- Oil Immersion is the technique of placing a drop of oil
between a 100X objective and the cover slip in order to improve
the resolving quality of the objective. It also can be placed
between the condenser and the glass slide.
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P
Parfocal
- The ability to rotate the objective turret without refocusing.
With stereo microscopes, parfocal is the ability to zoom throughout
the magnification range without re-focusing.
Parfocal
Length
- The distance between the surface of the specimen and objective
lens mounting position while the specimen is in focus.
Phase
Contrast
- An illumination technique used to examine live, unstained
specimens that have poor contrast or that are translucent.
Photomicrography
- The process of documenting images on film as seen through
a microscope.
Photo port - Any port other than an eyetube which is exclusively
used to connect cameras to a microscope.
Plan Objective
- An objective corrected for flatness of field so that when
you view the specimen it is in focus all across the image
field. There are also Plan Achromats, Plan Fluorites, and
Plan Apochromats.
Polarizer - A filter which can produce polarized light
and is usually used in conjunction with an Analyzer.
Polarized Light - Light waves which are uniformly aligned
in one direction.
Polarizing Components
- Polarizing Components are components that can be added to
an existing basic microscope to locate bi-refringent materials.
Prism - A solid piece of optical glass that has at least
two planes inclined towards each other from which light can
be reflected or refracted.
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R
Rack and Pinion
- Rack and Pinion is a mechanical design involving the intermeshing
of a geared wheel and matching vertical grooved rack used
in focus mechanisms.
Ramsden Eyepiece
- An eyepiece similar to the Huygenian eyepiece however it
has its focal plane either on or outside the surface of the
collective lenses.
Reticle - A piece of glass with a pattern printed on one
side that installs into an eyepiece which allows the pattern
to be imposed on the microscope field of view.
Resolving Power
- The ability resolve two points as two points at a given
distance.
Rotational Viewing
- A microscope set up in such a way that the eyepiece and
eyepiece tube can rotate around horizontally. Several people
gathered around the same instrument can thus view the same
specimen without moving around or having to move the microscope.
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S
Spherical Aberration
- A spherical aberration is an optical defect by which the
lens fails to form a sharp image. Rays of light which pass
through a lens near its edge are converged to a point nearer
the lens than those rays passing through the center of the
lens.
Stage
- The platform which holds the specimen. Types include: plain,
mechanical, motorized, heated, etc.
Mechanical Stage - moves the specimen East to West and North to South via
X-Y controls.
Rotating Stage - can usually rotate 360 degrees or, in the case of a rotating
mechanical stage, rotate as much as 270 degrees.
Stage Clips
- Chrome metal Fasteners located on the stage and placed over
slides to hold them securely in place while viewing.
Stage Micrometer
- A Stage Micrometer is used to calibrate an eyepiece micrometer.
Stand
- The stand is the basic component of the microscope which
holds all of the other components and usually contains the
light source (illuminator).
Stop Screw
- An adjustable screw located at the base of the focus rack
which, when adjusted properly, prevents the body tube from
lowering too far and potentially causing damage to both the
high power objective and the specimen.
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T
Teaching Head - An accessory that allows more than one
user to see into the microscope simultaneously.
Trinocular - A microscope head with two eyepieces and
a photo port.
Tube Length
- The Tube Length is the optical distance from the objective
to the eyepiece. Tube Length governs the interchangeability
of optical components; i.e. a microscope objective corrected
for 160mm tube length cannot be used on a microscope corrected
for infinity.
Turret-mounted
- Objectives that are attached to one common rotating nosepiece
that allows for quick and accurate objective positioning during
viewing.
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U
Ultra-violet
- The portion of the spectrum of light where the wavelengths
are above the visible spectrum.
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V
Video
Microscope
- Enables a specimen to be viewed on a video screen. Image
can also be analyzed by a computer using image analysis software.
Virtual Image
- Virtual Image is an image that does not converge in open
space.
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W
Wavelength - Light travels in waves varying in length.
The measurement of a light wave is from the top of one wave
to the top of the next one and is usually measured in units
of nanometers (nm) or Angstroms (A).
Wide Field Eyepiece - A Wide Field Eyepiece is an
eyepiece having a large field of view with a high eye point.
Working Distance - The distance from the objective
to the specimen with the image in focus.
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