OPERATION
Axio Imager
Illumination and contrast methods
Carl Zeiss
M70-2-0020 e 06/2009
430000-7344-001
167
If the positions of the section are more unfavorable, i.e. the center of the cross of optically uniaxial or the
isogyre of optically biaxial specimens is outside the objective pupil, the optical character can be assessed
as follows:
•
The specimen is
optically uniaxial
if the isogyres are
straight
and run (related to the reticle) parallel
through the pupil.
•
The specimen is
optically biaxial
if the black isogyres are
curved lines
traveling across the pupil on a
circular path.
Paying appropriate attention, also such axial figures not illustrated in Fig. 4-127 can be interpreted.
Axial figures can often be better represented by circular polarization. Especially the
determination of the axial angle of optically biaxial specimens (more or less the space between
isogyres) succeeds with a much greater unambiguity. The optical character can also be
determined by inserting the compensator
λ
(6 x 20) into the compensator slot.
4.9.7
Setting reflected-light brightfield
For all reflected-light contrasting techniques, the compensators 6x20 must be removed from
the light path (slot for compensators).
(1) Application
The reflected-light brightfield microscopy is the simplest and most widely used microscopy technique
which is used to examine opaque samples or specimens e.g. polished sections or wafers.
For a true-to-object imaging, indirect ray bundles, i.e. ray bundles diffracted and scattered on the
specimen details, are of major importance in addition to the so-called direct ray bundles. The higher this
portion of indirect rays (aperture), the more realistic the microscope image will be, according to ABBE's
rule.
The incoming, bundled light from the reflected-light illuminator is reflected by a neutral-colored beam
splitter. Then it passes to the objective which focuses the beams onto the specimen surface (so-called
condenser function). The objective collects the light reflected by the object and generates the
intermediate image of the microscope together with the tube lens, which is then observed visually or can
be documented objectively.
(2) Instrument
equipment
−
Axio Imager MAT with connected and adjusted HAL 100 halogen illuminator.
−
H P&C reflector module in reflector turret, 6x20 compensator mount with darkfield stop for reflected
light (424706-0000-000) or 4-position modulator turret.
