OPERATION
Axio Observer
Illumination and contrast techniques
ZEISS
12/2016
431004-7244-001
161
5.12.7
Setting up reflected light polarization
(1)
Application
Reflected light polarization presents a further contrasting option for polished sections of ore minerals,
coals, ceramic products, certain metals and metal alloys, as these specimens often exhibit varied reflection
behavior in linearly polarized light depending on the orientation of the crystals and specimen features.
The illumination light is linearly polarized by the polarizer and directed through the objective onto the
specimen surface, where it is reflected. Here, the light rays experience structure-dependent path
differences or polarization-optical rotations, which on passing the analyzer appear as different gray-scale
values.
With very low magnification objectives, a rotatable
λ
/4 plate in front of the objective (Antiflex cap)
permits the reflections to be eliminated even with "dark" specimen surfaces, which otherwise would be
unavoidable.
(2)
Instrument equipment
−
Axio Observer materials with attached microLED or adjusted HAL 100 illuminator
−
EC Epiplan-Neofluar, EC Epiplan objectives.
−
Fixed analyzer slider and Pol P&C or DIC P&C reflector module.
(3)
Setting reflected light polarization
•
Prepare the microscope as described in section 5.12.5 for reflected light brightfield.
•
Remove DIC slider (if inserted).
•
Swivel reflector module DIC/Pol P&C on reflector turret (Fig. 154/
7
) into the beam path or insert Pol
P&C reflector module and analyzer slider.
•
Focus and view the specimen in the polarization contrast which is now available.
Alternatively, a rotatable polarizer can be used on Axio Observer 3 materials, 5 materials and 7 materials
stands which have a slot for Polarizer slider RL 6x30, 90° rotatable (Fig. 157/
3
).
The use of the rotatable polarizer has the advantage that birefringence and pleochroism of anisotropic
samples can also be made visible even when no turntable is available.
In addition, some ore phases exhibit anisotropy in polarized reflected light which, depending on the
position of the polarizer, produces a color change a few d or - of the crossed position.
Содержание Axio Observer Series
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