-
Achromatic lens: a lens that
is specially designed and coated to correct for the tendency
of light to separate into colors when passing through glass.
An achromatic lens corrects this such that colors are more
accurate after being magnified.
Top
-
Binocular microscope: A compound
microscope with two eyepieces viewing down a single optical
channel and objective. This is different than a stereo
microscope, which has a separate optical channel for
each eye.
Top
-
C-mount & CS-mount: Also referred
to as C/CS-mount, it is a threaded standard developed for
mounting a lens to a camera. The mount is most commonly
used for video cameras (i.e., CCTV cameras, not camcorders),
and is used to mount cameras to microscopes. The mechanical
definition of both standards is 1" diameter, 32 TPI (threads
per inch), male on the lens (or microscope) side and female
on the camera side. The optical definition of the C-mount
is that the image reaches the focal plane, or camera's detector,
at 17.5mm past the edge of the lens' (or microscope's) mounting
threads. The CS-mount is identical in all respects except
the focal plane is 12.5mm past the mounting threads. A CS-mount
camera can be mounted on a C-mount lens or microscope by
using a 5mm extension ring. See also: T-mount.
Top
-
Coaxial Controls: A configuration
where one knob is centered on top of another. For example,
coarse and fine focus may have a larger coarse focus knob
with a fine focus knob on top of it (so the center of both
knobs is on the same axis). Also commonly used for Mechanical
Stage X/Y movement knobs.
Top
-
Compound microscope: A microscope
with multiple lenses, however this definition describes
virtually all modern microscopes. It would typically include
multiple user-selectable objective
lenses of varying magnifications and present a two-dimensional
view. Also see: stereo microscope.
Top
-
Condenser: The light rays
from the illuminator are condensed and focused through this
lens in the center of the stage, providing better image
resolution.
Top
-
Digital microscope: A microscope
and video camera combination with a digital output such
as USB or firewire. The microscope often includes software
to display the image on a PC.
Top
-
DIN Standard Objectives: (Deutsches
Institut fuer Normung) An international standard which dictates
the design compatibility of the objective lens. DIN standard
objectives from one manufacturer can be used in another
manufacturer's DIN standard compatible microscope.
Top
-
Doublet lens: a lens design that
is actually two different lenses cemented together (usually
one positive magnifier and one negative). This design is
used in widefield eyepieces to
obtain significantly better color performance than single
lens designs.
Top
-
Dual-view microscope:
A monocular microscope with a second,
vertical viewing port. The vertical port can be used with
an eyepiece for a second person, such as an instructor,
to view the specimen, or it can be used with an adapter
and a video or still camera. See also: trinocular
microscope.
Top
-
Eyepiece or Ocular: The lens
closest to your eye when looking through a microscope. A
binocular or stereo microscope will have two, a monocular
microscope will have one. The lensalso plays a critical
role in the total system magnification. See also widefield
eyepiece.
Top
-
Eyepiece Tube or Eyetube: The
tube into which the eyepiece lens (ocular) is set. This
is usually presented at an angle for comfortable viewing.
It may also be mounted in a vertical position such as on
a trinocular or dual-view microscope for either a second
viewer, or for a camera designed to fit inside an eyetube.
Top
-
FPS: frames per second: Used to indicate
the speed in which a video image is refreshed and displayed
on a monitor. In video microscopy this is usually controlled
by the camera. The faster the refresh rate (number is larger),
the "smoother" any movement of the specimen will appear.
Top
-
Interpupillary Distance:
Distance between the two eyepieces. Typically it is adjustable
to accommodate different users. Some microscopes also have
graduated scales to indicate the actual distance between
the eyepieces, allowing a user to determine the optimum
number and then quickly set it before each use.
Top
-
Koehler Illumination: A highly
effective illumination design.
Top
-
Magnification: Multiply the
magnification of the eyepiece by the magnification the objective
lens for the total magnification at that power. 400x or
1000x is necessary for studying cells and cell structure.
Top
-
Mechanical Stage: A mechanism
mounted on top, or as part, of the stage that allows the
operator to move the specimen slide in the X or Y direction
by turning a knob. Very useful at higher magnifications
as it can be difficult to move the slide by hand. Most mechanical
stages come with a graduated scale so you can see how far
the slide has been moved or keep track of the position of
various objects on the slide.
Top
-
Objective lens: The lens in
a microscope closest to the specimen. In a compound microscope
there are usually 3, 4 or 5 objective lenses allowing a
selection of magnification levels.
Top
-
Oil Immersion lens: A lens designed
to be immersed in oil. A drop of immersion oil is placed
on top of the cover glass and the lens is slowly lowered
until it rests in the oil. This allows the light to pass
through oil rather than air, and at higher magnifications
results in a crisper, higher contrast image. Primarily seen
on more advanced systems.
Top
-
Parcentered: A lens design
such that specimens that appear centered in the field of
view at one magnification level will also appear centered
when the magnification level is changed. See also: parfocal
Top
-
Parfocal: A lens design
such that specimens that appear in focus at one magnification
will also appear focused when the magnification level is
changed. The depth of field (how much of a specimen's height
will appear in focus at one time) changes significantly
when magnification is changed. The higher the magnification,
the shallower the depth of field. See also: parcentered
Top
-
Phase Contrast: A technique
using special objectives and condenser system to enhance
the contrast of unstained, relatively transparent specimens
such as blood and other tissue cells, thereby allowing microscopic
viewing of living tissue. It is a sophisticated technique
that shifts the light "phase" 1/4 wavelength, causing any
light deviated by the specimen to appear dark on a light
background.
Top
-
Rack Stop: A safety feature consisting
of a mechanical stop, typically adjustable, which prevents
the objective lens from hitting
the microscope stage.
Top
-
Seidentopf: a head design
where the interpupillary adjustment (increasing or decreasing
the distance between the eyepieces) is achieved by twisting
the eyepieces in an up and down arc motion like binoculars.
Top
- Slip
Clutch: A safety device usually located on the focus
knob allowing the knob to "slip" and continue turning when
it reaches the end of its travel, or if it runs into the
stage. Due to the gear ratios involved, without this it
may be possible to damage the mechanism by applying too
much force to the knob after it has reached the end.
Top
- Stage:
The platform that holds the slide up beneath the objective
lens.
Top
-
Stereo microscope a.k.a. dissecting
microscope: A microscope with a separate optical channel
for each eye (eyepieces and objectives) which allows viewing
in three dimensions. See also: compound
microscope.
Top
- Turret
or Objective Turret: The rotatable metal piece into
which the microscope's objective lenses
are attached. A "turret" style stereo
microscope refers to the type that has more than one
objective lens which can then be rotated into position.
On a compound microscope the turret
is the ring holding the objective lenses allowing the operator
to rotate them into position as needed.
Top
-
T-mount: A photographic mechanical
mounting standard developed in 1957 originally intended
as a universal lens mount for 35mm cameras. There are now
T-mounts available for a large variety of digital and film
cameras making it a good method for mounting cameras to
microscopes. The thread (a.k.a. T-thread) is specified as
42mm diameter and 0.75mm pitch, or M42-.75. See also:
C-mount
Top
-
Trinocular microscope: A binocular
microscope with a third, vertical viewing port. The vertical
port can be used with an eyepiece for a second person, such
as an instructor, to view the specimen, or it can be used
with an adapter and a video or still camera. Click here
for an example. See also: dual-view
microscope.
Top
-
Widefield eyepiece (WF): an
eyepiece with an achromatic doublet
lens designed in such a way that itdoes not have to
be limited to viewing only in its center, and the portion
of the lens that allows non-distorted viewing is larger
than a normal lens. This appears to the user as a bigger
aperture or "hole" to look through. It therefore has the
advantage of being easier to use and more forgiving of a
user's head movements. An eyepiece listed as WF10X/18mm
would indicate it has a widefield achromatic doublet lens,
10X magnification and is 18mm in diameter.
Top
|
