ZEISS
OPERATION
Axio Imager 2
Illumination and contrast methods
180
430000-7544-001
01/2016
4.12.6
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 yields 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, on 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 by a wide-open cone. In practical microscopy this means that the condenser front lens (0.9 or
1.4) must be in the light path, the aperture diaphragm fully open and the objective should also have a
large aperture.
(1)
Application
The determination of the optical character of transparent and weakly absorbing crystals is used to
diagnose crystals. This method is also termed conoscopy. Its main application is classical mineral
microscopy. However, it also allows synthetic crystals, industrial minerals and plastics (e.g. films) to be
identified and characterized.
(2)
Instrument equipment
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Stand with installed phototube Pol or with Bertrand lens slider or with the tube lens turret with
integrated Bertrand lens optics
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Strain-free objectives
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Achromatic-aplanatic universal condenser 0.9 H
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Rotary stage Pol
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Polarizer D (rotatable or fixed)
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Analyzer slider or analyzer module D in reflector turret
The phototube Pol can be installed on all Axio Imager stand types.