5.6 Abbe condenser
Beneath the object stage an Abbe condenser N.A. 12.5 is mounted. The condenser is factory pre-centered but can be
adjusted in height by means of a rack and pinion movement and knob. With this, one can focus the light on the specimen
by which the contrast can be optimized. If needed the following procedure can be used to center the condenser:
1.
Move the condenser to the highest position
2.
Select the 10x objective into the light path and focus the specimen
3.
Rotate the field diaphragm adjustment ring to put the field diaphragm to the smallest position
4.
Rotate the condenser up/down knob, and adjust the image to be clearest
5.
Adjust the center adjustment screw and put the image to the center of the field of view
6.
Open the field diaphragm gradually. If the image is in the center all the time and inscribed to the field of view,
the condenser has been centered correctly
5.7 The field (Köhler) diaphragm (A)
By limiting the diameter of the beam entering the condenser, the
field diaphragm can prevent stray light and enhance the image
contrast. When the image is just on the edge of the field of view, the
objective can show the best performance and obtain the clearest
image. The diaphragm is factory pre-centered.
5.8 Adjusting the Aperture Diaphragm (B)
•
The diaphragm is used to adjust the Numerical Aperture of the
condenser. When the N.A. of the condenser matches the N.A.
of the objective, the highest possible resolution is obtained
•
When contrast is low, rotate the diaphragm adjustment ring
to 70% to 80% of the N.A. of objective. This will improve the
contrast of the image. The diaphragm is factory pre-centered.
5.9 Use of the S100x oil-immersion objective
The MSU-600 Series is equipped with an S100x N.A. 1.25 oil
immersion objective. Please follow these instructions for use:
1.
Remove the dust protection from the revolving nosepiece
to mount the S100x objective
2.
Focus the image with the S40x objective
3.
Turn the revolving nosepiece so the S100x objective almost reaches the click-stop
4.
Put a small drop of immersion oil on the center of the slide
5.
Now turn the S100x objective so that you feel the click stop
6.
The front lens is in contact with the immersion oil
7.
Look through the eyepiece and focus the image with the fine adjustment knobs
8.
The distance between the lens of the objective and the slide is very small!
9.
In case there are small bubbles visible turn the S100x objective a couple of times left/right so that the front of
the objective moves in the oil and the bubbles will disappear
10.
After using the S100x objective turn the table with the fine adjustment knobs downwards until the front lens
doesn’t touch the oil any longer
11.
Always clean the front lens of the S100x objective with a lens paper moistened with a drop of isopropanol
12.
Clean the slide after use as well
5.10 Safety device
To prevent damage to the objective lens or the slide, all types are equipped with a pre-fixed safety device. It is
recommended to use slides of 1.0 – 1.2 mm thickness in combination with cover glasses of 0.13 mm or 0.17 mm thickness.
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