65
7. Start-up
7.6.1 Transmitted Light
If your microscope has not yet been set up for
Koehler illumination, please continue with the
"Koehler Illumination" section.
• Select an objective with moderate
magnification (10x-20x).
• Activate the transmitted light axis with the
TL/
IL
button (84.1).
• Press the
BF
button to activate the brightfield
contrast method (one of the variable function
buttons on the stand).
• Place a specimen on the stage.
• Focus the specimen using the SmartMove or
the focus wheels.
• Adjust the light intensity with the
INT
buttons
(84.3).
• Close the field diaphragm with the
FD
button
(84.4) or manually until the edge of the
diaphragm appears in the field of view.
• Using the condenser height adjuster (90.2),
adjust the condenser until the edge of the
field diaphragm appears in sharp relief.
• Open the field diaphragm just enough for it to
disappear from the field of view (91d).
Note:
The condenser height setting is dependent on
the thickness of the specimen and may require
adjustment for each new specimen.
Koehler Illumination
Suitable aperture and field diaphragm values
have been preset for each objective. The con-
denser has also been centered at the factory.
However, it may be necessary to readjust the
condenser in some cases. Therefore, check the
condenser centering.
The following procedure is provided for the
transmitted light-brightfield illumination.
All required functions can be executed at the
touch of a button with the Leica DMI 6000 B
electronic microscope. (See Chapter 8, Opera-
tion).
Preparation:
• Configure the microscope as follows:
Set up the illumination, condenser, objectives
and eyepieces correctly. (Please make sure
that the objectives are properly screwed in
and check the eyepiece settings.)
• Switch the microscope on and wait for the
initialization phase to complete (automatic
functions only).
• You will need either an empty Petri dish
(preferably with a glass bottom) with a
marking in the middle or a stained specimen
on a slide with a coverslip.
• Switch to the 10x objective (if not present, the
20x objective).
