Nexcope NE620T - Page 38

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5
VARIOUS OBSERVATION METHODS
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Illustration 026 C-D: Settings for dark field observation: Inserting the BF/DF slider.
With the BF/DF slider an observation
in bright field and dark field is pos-
sible:
Loosen the right-hand screw (5) of the BF/
DF slider (6).
Insert the BF/DF slider into the correspond-
ing hole of condenser (7).
Attach the right screw (5) of the BF/DF slider
and screw it tight.
The screws on the left and right side
hold the BF/DF slider in position.
Turn condenser up-down knob to raise the
condenser (see picture A reverse process).
The condenser lens should not touch
the slide.
By pulling or pushing the right or left screw,
you can quickly and easily switch between
bright field (BF) and dark field (DF) obser-
vation.
When inserting the slider, make
sure that the BF/DF label is facing
you.
The slider can be inserted from both
sides of the condenser. More space
is available on the left side.
Make sure that the BF/DF slider is
always fully aligned in the light path.
For optimal dark field observation:
Add a drop of cedar oil/immersion oil (8)
between the condenser and the specimen so
that the light is not completely reflected on
the condenser and reaches the object to be
examined.
Add an additional drop of cedar
oil/immersion oil on the cover glass
of the sample when using the 100x
objective.
Setting a background for the field of view
that is as dark as possible.
Turn the aperture diaphragm ring (10) com-
pletely to the left to position 100/PH/D.
Turn the brightness control knob (11) to ad-
just the lighting.