Ken A Vision T-1941 User manual

Comprehensive Polarizing
Scope
Instruction Manual
T-1941

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Thank you for purchasing a Comprehensive Polarizing
Scope
Packing List
Dust Cover
Fuse
10x Widefield Eyepiece with Graduated Cross Hair
Instruction Manual
Warranty Card & Sheet
Application
The Ken-A-Vision Comprehensive Polarizing Scope has a multitude
of applications. A primary use of polarizing microscopes is in geological
applications such as the studying of rock thin sections. A polarizing
microscope used with anisotropic materials allows the study of the
absorption color and boundaries between minerals of differing refractive
indices. Additionally, isotropic and anisotropic materials can be
differentiated in specimens such as natural and industrial minerals
(manufactured, refined or extracted). Every day materials such as
ceramics, polymers, and cements can be examined for their structure.
More recently many highly ordered biological materials such as wood,
starch, urea, DNA and collagen reveal new structural properties when
examined under polarized light.
Polarized light is a contrast-enhancing methodology that can improve
the quality of images obtained with birefringent materials, and may be
better than images obtained with darkfield or brightfield illumination,
phase contrast or fluorescence microscopy.
The Ken-A-Vision Comprehensive Polarizing Scope may be used
both as a polarizing microscope (both analyzer and polarizer filters in light
pathway) or as a brightfield microscope with the filters rotated out of
position.

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SPECIFICATIONS
Specifications subject to change without notice
Cross hair reticle (graticule) marks the center of the field of view
Catalog Number T-1941
10x Widefield Eyepiece with cross hair reticle
(graticule) X
Monocular Head X
3 Hole, Reversed Nose Piece X
4x, 10x, 40xR DIN Objective Lenses X
Coarse and Fine Coaxial Focal Adjustment X
Rotating Stage with Clips; Marked in 360 ° Increments X
Stage Marked in 360 ° Increments X
Analyzer Filter (may be rotated in or out) X
Polarizer Filter (may be rotated in or out) X
Illuminator 20 Watt Halogen Bulb (with light rheostat) X
Rheostat (variac) for Light Intensity Adjustment X
Adjustable Abbé Condenser X
Iris Diaphragm X
Bertrand Lens Optional
Compensators/Retardation Plates Optional

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Microscope Preparation
Open packing box carefully, and lift microscope out of shipping
container. Remove all packing materials on eyepieces, stage, and
illuminator.
Check the coarse focus tension. The knobs are oversized, designed
for better gripping. The coarse (larger) focus knob should turn easily to
change the focus. The stage should move up and down when either the
coarse or fine adjust knobs are turned. Watch the up-down motion of the
stage; it should not drift or slip on its own.
Check the stage stop feature. The stage stop is a knurled thumb
screw with a lock nut found on the main frame, just behind the stage. To
check the stage stop, place a prepared slide in normal position for
viewing. Place the 40x objective into viewing position and move the
coarse focus knob until the object and stage are as close together as they
can be WITHOUT TOUCHING. Look through the eyepiece at the slide,
and get the specimen into focus. The objective should be very close to
the slide, but not touching. If the stage stop is not set correctly, loosen the
locking nut and thumb screw, and reset the stage stop, tightening both
when correct position is attained.
Microscope Use and Instructions
Visit the Ken-A-Vision Web site http://www.ken-a-vision.com/pdf/
MicroscopePrimer.pdf, for a Microscope Primer on general microscope
usage.
Power Switch
Plug your microscope into a power source. This microscope has an
on/off switch at rear right of the microscope. On the left side of the
Microscope is a rheostat for adjustment of light intensity. Be sure it is
turned up once microscope is on.
Rotating Circular Stage
Your Ken-A-Vision Comprehensive Polarizing Scope comes
equipped with a 360-degree rotatable circular stage for performing
orientation studies in polarized light. This stage has a goniometer divided
into 1-degree increments.
It is important that the stage is centered within the optical axis. Find
the two centering knobs located on the front of the stage, sticking out
about 45 degrees from the center line. To center the optical axis, while
looking through the microscope eyepiece, first reduce the iris diaphragm
to its minimum level. Using the adjusting centering knobs while looking

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through the eyepiece, be sure that a uniform field of light is present with
no shadows at any edge of the field. The condenser is spring loaded at
the back of the stage and may be pushed in using the knurled center
knob. Once the optical axis is aligned, the diaphragm may now be
reopened to full diameter.
The viewfield of the microscope was factory set, and will rotate with a
little deviation off of center.
Just above the nose piece find a slot in the body tube. Note that it is
positioned between the polarizer and the analyzer polarizing lenses and
by convention runs in a southeast-northwest direction. The primary
purpose of this slot is to allow insertion of an accessory or retardation
plates between the polarizer and analyzer, in a specific orientation with
respect to the polarizer and the analyzer lens vibrational directions.
(Additional notes and descriptions of various kinds of compensators may
be found at www.ken-a-vision.com in a short primer on polarized light and
polarizing microscopy).
Focus
The basic principle involved in Polarizing Microscopy is to take
advantage of the fact that over 90 percent of all solid substances (aniso-
tropic) have optical properties that vary depending upon the orientation of
the incident light with the crystallographic axis. As specimens are exam-
ined under polarized light, there are refractive indices created which are
dependent upon both the propagation direction of light through the sub-
stance and on the vibrational plane coordinates due to the polarizing
lenses. The anisotropic specimen will act as a beam splitter, dividing light
rays into two parts. The polarizing microscope exploits this interference
of the split light rays as they are re-united along the same optical pathway.
Place a specimen slide under the stage clips. Using the coarse
adjust knob, lower the stage until the specimen is in focus. Use the
smaller fine adjust knob to now sharpen the focus and attain maximum
resolution. This first step may be done with the polarizing filters in or out
of the light pathway.
Using the Comprehensive Polarizing Scope - Polarizing
Microscopy
Good practice is to check your Comprehensive Polarizing Scope by
doing the following quick exercise. Do this without any specimen in the
light pathway to be sure that the polarizer and analyzer filters are correctly
aligned.

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The polarizer lens is located in a filter holder attached to the
illuminator, below the condenser of the microscope. It is capable of being
rotated 360-degree (360°). Below the front of the polarizer is a small line
indicating a "zero" or starting point. Align the 0° mark on the polarizer
with that 'zero' line. When the polarizer is aligned with that mark, the lens
is said (by convention) to be set to East-West (abbreviated E-W). Now
rotate the analyzer polarizing lens into position within the eye tube. The
convention here is that the vibrational direction of this lens is in the North-
South orientation (abbreviated N-S). In this position, light from the
illuminator will be mostly, if not entirely blocked (extinguished), and if you
look through the microscope it should be dark at even the brightest light
setting.
Now rotate the polarizer and try to determine the point when the most
light comes through the two filters. This should occur at 90°. Total
extinction should reoccur at 180°, and maximum light again at 270° with
total extinction again at 360° or 0°. Accuracy of this alignment is
important, when retardation and/or compensation plates are inserted into
the optical path for measurement purposes.
The iris condenser, supplied as part of the Abbé condenser, controls
the angle of the illumination cone that passes through the microscope's
light pathway. Reducing the opening size of this iris diaphragm
decreases the cone angle and increases the contrast of images
observed. For polarization studies and for greatest accuracy, use the
dimmer (variac) switch to change the intensity of illumination, rather than
the iris diaphragm.
Eyepiece
The widefield eyepiece is locked into place to avoid loss. A set of
crossed, perpendicular lines are mounted in the eyepiece.
The analyzer filter is provided within the eyepiece tube, directly below
the eyepiece. This must be in the eye tube when using the microscope as
a polarizing scope, and may be rotated out of the light line, when using
the scope as a Brightfield illuminated microscope.
Care and Maintenance
Your microscope is a fine precision instrument and should be treated
with care. When not in use, it should be protected from dust by the plastic
cover provided. Lenses and eyepieces should be cleaned periodically
with optical lens tissue which is soft and lint free. Painted surfaces can be
cleaned with a moistened cloth.

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Ken-A-Vision has quality technicians on staff to repair or service your
microscopes. Ken-A-Vision recommends service every two years for
optimal life of the product. Contact Ken-A-Vision at 1.816.353.4787,
Extension 5620 for more details.
Technical Specifications for Model No. T-1941
Comprehensive Polarizing Scope
For the technical specifications on the Comprehensive Polarizing Scope,
visit the Ken-A-Vision Web site http://www.ken-a-vision.com/t1941.asp

5615 Raytown Road • Kansas City, MO 64133 U.S.A.
Tel.: [phone] • Fax: [phone]
email:[e-mail] • www.ken-a-vision.com
INS-SC8POL
Accessories
If you are interested in purchasing accessories or replacement parts for
your Comprehensive Polarize Scope visit our Web site,
http://store.kenavision.com/catalog/ or contact your local Ken-A-Vision
Dealer.
Ken-A-Vision reserves the right to make design improvements and other changes in accordance with the
latest technology. There is no obligation to make changes in products already manufactured. Patents
Pending Copyright 2007 Ken-A-Vision Corporation.
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