Positive and negative phase contrast, central dark field
Lightinglateral modulator for phase contrast and picture lateral modulator for phase contrast KT einscnalten; Polarizer,
λ
-und
λ
/4 plate switch off; Green filters switch on.
Bertrandlinse switch on. If necessary correct cover of the modulator figures (with ring screen). Aperture diaphragm
close, until in the exit pupil of the objective only the large and small ring is visible: normal phase contrast (and/or
normal dark field,), which small ring is visible, strict phase contrast (and/or strict dark field).
Bertrandlinse switch off.
To the change between positive and negative phase contrast as well as central dark field it meets to switch on only the
desired modulator KT through tricks of the gun KT.
Quasi-light field: Aperture diaphragm fully open
With the objective 12,5x only normal phase contrast and/or normal dark field is possible. For overview light field Modula cond on free
passage scolded.
The contrast abates with surveying the preparation, over Bertrandlinse cover of the modulator figures kontrol lieren. With shifting
keiliger preparations the ring of pictures can apart-run.
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Dark field
Dark field with the DF-condensor lens 1,2
By its high aperture and in connection with the integration ring lens supply the condensor lens darks field of maximum luminous intensity
for objectives with enlargements from 25x to REAR ONE 100x ten. Rear objectives with apertures > 1 must be provided with an iris
screen. The condensor lens requires homogeneous immersion between condensor lens front lens and preparation.
Operation:
Condensor lens with a trailer to at the stand installs; it makes certain that a trailer sits downward on attack. Condensor lens
change
►
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.
Set screw (fig. 3/31) on approximately 10 mm of length herausschrau users.
, Applies a drop immersion oil downward drives condensor lens with condensor lens impulse some millimeters away from the
upper attack on the condensor lens front surface (favourable-further drops on the lower surface of the slide up
bring - drops in work situation of the preparation hanging!). Condensor lens with impulse upward drive, until the area between
condensor lens front lens and slide lower surface is filled out with oil bubble-free.
Preparation with work objective focus
Annunciator screen close
Leuchterscheinung in the field by lifting or lowering the condensor lens on as small a diameter as possible bring and with
centering screws of the condensor lens in the field center
Annunciator screen open, field observe.
If the cut width of the condensor lens is fully used, slides up to
≤
1.5 mm of thickness for observations in the dark field can be used.
