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OPERATION
ZEISS
Illumination and contrast methods in transmitted light …
Axioscope 5/7/Vario
106
430035-7344-001
03/2018
4.2.7
Setting transmitted light polarization for conoscopic observation - determining the
optical character of crystals
For the classification (and thus identification) of crystalline matter, the examination of the interference
image in the objective pupil delivers more valuable information than that obtained by viewing the
specimen itself. The interference image becomes visible in the eyepiece if an additional optical system
(fixed or focusing Bertrand lens or, in the basic version, the auxiliary microscope or diopter) is used.
In contrast to orthoscopy, this technique is called conoscopy, because here the specimen is ideally
illuminated through a wide-open cone. In practical microscopic work, this means that the condenser
front lens (0.9) must be in the light path, the aperture diaphragm fully open, and the objective, too,
should be a high-aperture type.
4.2.7.1
Application
The determination of the optical character of transparent and weakly absorbent crystals is used to
diagnose crystals. This method is also termed conoscopy.
Its main application is classical mineral microscopy. However, it also facilitates the identification and
characterization of synthetic crystals, industrial minerals and plastics (e.g. films).
4.2.7.2
Simple conoscopy using the auxiliary microscope or the diopter
(1) Microscope configuration
−
Recommended strain-free objectives:
N-Achroplan 50x/0.9 Pol objective or
EC Plan-Neofluar 40x/0.9 Pol objective
−
Axioscope stand for polarization with auxiliary microscope or diopter
−
Pol rotary stage
−
Pol binocular photo tube
or
eyepiece with crossline micrometer 14:140 (454060-0000-000)
and
adjustment aid for polarization microscopy (453679-0000-000)
−
Achromatic-aplanatic 0.9 H Pol condenser or 0.9 Pol condenser
−
D polarizer (rotatable or fixed)
−
analyzer slider or D analyzer module in the reflector turret or reflector slider