3
3.2 Eyepiece
The eyepiece is secured to the eyepiece tube. Binocular viewing
bodies do not utilize set screws to secure the eyepieces.
3.3 Substage Condenser
The Leica BM E Compound Microscope is equipped with one of two
available substage condensers:
• 0.65 N.A. condenser, a five-position aperture disc diaphragm
which is color coded to match the objective markings.
• 1.25 N.A. (fixed) Abbe Condenser on a spiral mount
4.0 Operation
CAUTION:
The top collector lens of the illumination system in
the base of the microscope may become warm or hot. Avoid
touching the lens directly.
The Leica BM E mroscope should always be used on a hard, stable
and level surface such as a laboratory table or work bench.
4.1 Illumination
4.1.1 Built-in Illumination System
The Leica BM E Compound Microscope should only be plugged into
a suitably grounded electrical outlet. A grounded threewire cord is
provided.
To turn on the electrical power, flip the switch located on the back left
of the base of the BM E. If you have the Tungsten-Halogen model, the
intensity control which is located on the left side of the base should
be turned all the way down before turning the instrument off.
4.1.2 External Illuminator and Mirror
Position the external illuminator approximately 5cm (2”) in front of the
mirror.
NOTE:
Not all Leica BM E Compound Microscopes are equipped with
a mirror. While looking through the eyepiece adjust the mirror to pro-
vide the brightest and most evenly illuminated field-of-view.
4.2 Stage Preparation
Lower power objectives have a greater depth of field and are gene-
rally used for initial focusing and viewing. The lower the objective
power, the greater area of specimen surface will be seen in the field
of view.
Before placing a specimen on the stage, rotate the nosepiece until
the lowest power objective is in the viewing position.
Be certain that the stage surface is free of dust, grit, or any other mate-
rial. These will scratch the slide or stage or may interfere with the
movement of a slide across the surface of the stage.
Place the slide under the stage clips with the cover glass facing
upward. If using a graduated mechanical stage, place the slide bet-
ween the stage fingers.
Position the specimen area of the slide over the center of the stage
aperture. When using a graduated mechanical stage, use the stage
control knobs to move the specimen slide.
Raise the stage by turning the coarse focus knob until the stage rea-
ches the upward stop. Do not view the slide through the eyepiece at
this point.
The Leica BM E Compound Microscope is ready to be focused.
4.3 Focusing
Using the 4x or 10x objective, focus the Leica BM E Compound
Microscope by looking through the eyepiece and turning the fine focus
knob. Continue to view the specimen through the eyepiece until a
crisp, clear image appears.
Adjust the aperture disc diaphragm condenser to match the objec-
tive being used to obtain the clearest possible image. Adjust the fine
focus knob to sharpen the image to the center of the field of view.
If using the 1.25 N.A. Abbe condenser, focus by moving it up and down
in its spiral sleeve to the point at which the field is most evenly illumi-
nated. Adjust the iris diaphragm by sliding the control lever to obtain
the clearest image.
The position of the aperture must be reset when changing to higher
power objectives. As magnification increases, the aperture diaphragm
must be opened.
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