OPERATION
Carl Zeiss Illumination and contrast methods Axio Imager
162 430000-7344-001 M70-2-0020 e 06/2009
4.9.5.4 Transmitted-light circular polarization contrast
(1) Use
Unlike standard polarization contrast, circular polarization contrast does not show any dark (extinction)
positions that depend on the angle of rotation (azimuth) of the specimen relative to polarizer or analyzer.
This means, that the image will always look the same while you rotate the stage, as there are no bright
and dark positions. With optical anisotropy, all transparent specimens show the interference colors that
are characteristic to them.
(2) Microscope configuration
− Phototube Pol
− Achromatic-aplanatic universal condenser Pol
− Strain-free objectives
− Rotary stage Pol
− Polarizer D (rotatable or fixed)
− Circular polarization equipment D, ACR, with λ/4 plate, rotatable for transmitted light, including
reflector module λ/4, ACR, P&C (427703-9901-000)
− Analyzer slider
(3) Setting the microscope
• Set the microscope as for transmitted-light bright field according to KÖHLER (see Section
4.9.1 (3)).
• Center rotary stage Pol and objectives (if not done yet - see Sections
3.34.3, 3.34.4).
• For the further settings, for the time being do not use a specimen.
• Push the analyzer slider (
4-125/6) into the light path.
• Install the circularpolarizer D (see Section
3.35), and insert reflector module λ/4, ACR, P&C (4-125/5) in
the reflector turret.
• Swivel the bottom part of the circular polarizer D (
4-125/3) into the light path up to the click stop and,
at full light intensity, assess the extinction (darkening) of the field of view without specimen.
If the extinction is not optimal, correct the position of the vibration direction by slightly and sensibly
turning on the polarizer mount (for this, use the adjusting slots (
4-125/4) on the bottom of the
polarizer), until the extinction is maximum. Normally, however, this will not be necessary, as the
position of the vibration direction of the polarizer is factory-adjusted.
• Then, swivel the top part of the circular polarizer D (
4-125/2) into the light path.
• Rotate the lever of the λ/4 plate of the circular polarizer D (
4-125/1) until the extinction is maximum
(dark-gray field of view) (lever points 45° to the right).
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