OPERATION
ZEISS
Illumination and contrast methods in transmitted light …
Axioscope 5/7/Vario
104
430035-7344-001
03/2018
−
A dark gray appearing as the interference color suggests very small path differences (
λ
/10 or
54.6 nm).
The compensator appropriate for this application:
Rotary compensator Brace–Köhler
λ
/10
(Accessory 000000-1115-703).
•
Push the compensator into the slot as far as it will go.
For measurement preparation and measurement procedure, use the enclosed operating instructions.
4.2.6.4
Circular polarization contrast
(1) Application
Unlike standard polarization contrast, circular polarization contrast does not show any dark (extinction)
positions that depend on the angle of rotation (azimuth) of the specimen relative to polarizer or analyzer.
This means that, while you are rotating the stage, the image will always look the same, as there are no
bright and dark positions. With optical anisotropy all transparent specimens show the interference colors
that are characteristic to them.
(2) Microscope configuration
−
Strain-free objectives
−
Pol rotary stage
−
DF circular polarizer (no polarizers may be mounted on the condenser), including the corresponding
λ
/4 plate
−
analyzer slider or D analyzer module in the reflector turret
(3) Setting the microscope
•
Set the microscope as for transmitted light brightfield microscopy using the KÖHLER method (see also
section 4.2.1).
•
Center the Pol rotary stage and objectives (if not yet done - see sections 3.1.10 and 3.1.10.6).
•
For the further settings,
do not
use a specimen for the time being.
•
Place the analyzer in position.
•
Swivel the lower part of the D circular polarizer (Fig. 4-12/
3
) into the light path up to the click stop
and swing in the analyzer module on the reflector turret or insert the analyzer slider into the
intermediate plate (if applicable). At full light intensity, assess the extinction (darkening) of the field of
view without specimen.
If the extinction is not optimal, correct the vibration direction of the polarizer by slightly and carefully
turning the polarizer mount using a small screwdriver (for that, use the adjusting slots (Fig. 4-12/
4
) on
the bottom of the polarizer) until you obtain maximum extinction. Normally, however, this is not
necessary because the vibration direction of the polarizer is factory-adjusted.
•
Push the 6x20 mm slider with the
λ
/4 plate (Fig. 4-12/
5
) belonging to the polarizer into the
compensator slot above the nosepiece as far as it will go.
