OPERATION
Carl Zeiss
Illumination and contrast methods
Axio Imager
164
430000-7344-001
M70-2-0020 e 06/2009
4.9.6
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 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, on the basic version, the auxiliary microscope or diopter) is used.
In contrast to orthoscopy, this technique is called conoscopy, because here ideally the specimen is
illuminated through a widely open cone. In practical microscopic work, 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,
too, should be a high-aperture type.
(1) Use
The determination of the optical character of transparent and weakly absorbing crystals serves to
diagnose crystals. This method is also termed conoscopy. Its main application is the classical mineral
microscopy. It allows, however, also synthetic crystals, industrial minerals and plastics (e.g. films) to be
identified and characterized.
(2) Microscope
configuration
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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.