OPERATION
Axiolab 5
Illumination and contrast methods in transmitted light
ZEISS
05/2019
430037-7444-001
97
NOTE
For a high-contrast image with higher-magnification objectives (from approx. 20x) the
illumination aperture must be reduced to a value between 0.15 and 0.20, i.e. the aperture
diaphragm must be closed accordingly.
The effect of the lambda/4 plate (Fig. 4-10/
4
) can be undone by either swiveling it out of the
beam path or turning it with the lever (Fig. 4-10/
3
) into one of its two click-stop positions.
(4) Sample differentiation between gout and pseudo-gout
•
Move two polarizers to the dark position (the analyzer is oriented NORTH-SOUTH, while the polarizer
is oriented EAST-WEST).
•
Swivel in the lambda plate and, if a
rotary
lambda plate is available (e.g. 445226-0000-000), set the
oscillation direction to 45° (
γ
, stop position).
•
Select crystal needles that are oriented in the gamma direction (see marking on the lambda plate).
(5) Analysis
•
If the crystal needles oriented parallel to the gamma direction of the lambda plate are yellow, and the
crystal needles lying at a right angle to the gamma direction are blue, the crystals are monosodium
urate crystals (gout).
•
If the crystal needles oriented parallel to the gamma direction of the lambda plate are blue, and the
crystal needles lying at a right angle to the gamma direction are yellow, the crystals are calcium
pyrophosphate crystals (pseudo-gout).
This analysis is also possible using a polarizer with a fixed lambda plate which can be placed on the
luminous-field diaphragm. In that case, the lambda plate does not have to be rotated.
