Zeiss Axioskop 2 plus Operating Manual page 101

Axioskop 2 plus
Axioskop 2 mot plus
• Turn the mechanical stage with specimen, e.g. an artificial fiber until the specimen displays maximum
darkness. The fiber is now parallel to one of the two directions of the crosslines. If pronounced
deviations (5° and more) occur, a polarization microscope must be used.
☞
The interpupillary distance of the binocular tube must no longer be changed now, since
otherwise the angle position of the crosslines with reference to the fiber will be changed.
• Turn the stage by approx. 45° until the longitudinal axis of the fiber is oriented in NE-SW (3-23). The
specimen now features optimum brightness (diagonal position). In this position, the specimen can
display any color.
• Push in the compensator λ.
Like the specimen, the compensator λ is a
birefringent object, though with a defined path
difference of 550 nm and the largest vibration
direction n γ defined to be oriented in NE-SW
direction
The specimen changes its color when the
compensator λ is pushed in. The type of the color
change depends on the orientation of the
specimen (NE-SW or NW-SE).
The color changes
interference. The
differences) in both diagonal positions (NE-SW and
NW-SE) of the specimen must be compared.
The path difference
superimposition (interference) of the vibration
direction of the specimen and that of the
compensator λ.
The highest path difference occurs if the vibration
direction of the specimen with the absolutely or
relatively highest refractive index (n γ or n γ' ) is
parallel to the largest vibration direction of the
compensator λ. The specimen will then appear in
greenish-blue, for example.
The smallest path difference occurs if the vibration direction of the specimen with the absolutely or
relatively lowest refractive index (n α or n α' ) is perpendicular to the vibration direction of the
compensator λ. The specimen then appears in yellow, for example.
B 40-075 e 02/01
Illumination and contrasting techniques
are caused by
interference colors
results from
OPERATION
optical
(path
the
Fig. 3-24 Diagram of the Michel-Lévy color
charts
Carl Zeiss
3-33