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OPERATION
ZEISS
Illumination and contrast methods in transmitted light
Axiolab 5
110
430037-7444-001
05/2019
•
Configure the microscope as for transmitted
light brightfield microscopy using the KÖHLER
method (see section 4.2.1).
•
Swivel the polarizer (Fig. 4-13/
3
) into the beam
path and, if it is rotatable, position it at 0°.
•
Swivel the analyzer into the beam path and
bring into a crossed position with the setting
wheel. (The field of view will now appear dark)
•
Place the specimen on the stage and focus on
it.
•
Swivel the analyzer into the beam path (
On
position) with rotary knob
A
2
). The
polarization direction can be changed using the
setting wheel (Fig. 4-17/
4
) of the analyzer.
ATTENTION
The movements of rotary knobs
A
and
BL
and the respective setting wheels are coupled to
each other. Only
one
control element should therefore be operated at a time and the
movement of the other should not be inhibited or blocked. Otherwise, mechanical damage
may occur.
NOTE
If rotary knob
BL
is set to the
On
position, rotary knob
A
will be automatically set to the
On
if
it is not already there.
If, on the other hand, rotary knob
A
is set to the
Off
position, rotary knob
BL
will be
automatically set to the
Off
position if it is not already there.
•
Place a selected crystal in the center of the crossline reticle.
•
Swivel in the objective N-Achroplan 50x/0.8 Pol or EC Plan-Neofluar 40x/0.9 Pol and focus with the
focusing drive.
•
If necessary, close the luminous-field aperture to avoid superimposition of axial figures of neighboring
crystals on the axial figure. The smallest crystal range that can be faded out is approx. 170 µm.
•
Switch on the Bertrand lens
BL
1
) (Position
On
). The axial figure will appear in the field of
view.
•
Bring the axial figure into focus with the setting wheel (Fig. 4-17/
5
).
(3) Evaluation
Crystalline anisotropic specimens can be separated into optical uni- and biaxial, in each case with an
"optically positive" or "negative" character.
Uniaxial
crystals display a
black cross
when the optical axis is parallel to the direction of view.
Depending on the level of birefringence and the specimen thickness
, concentrically arranged
colored
interference rings
(so-called isochromes) may appear (see also Fig. 4-12, second row).
Fig. 4-17
Axiolab 5 for transmitted light
conoscopy