KERN OBL 145, User Instructions

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OBL-14-15-BA-e-1610 20
To use this, you need to position the desired PH objective in the beam path and
furthermore to place the corresponding PH slide into the insertion point of the PH
condenser.
With the surface marked with the magnification information facing up, the PH slider is
pushed into the insertion point on the PH condenser until stop. At this position the
phase ring of the PH slider is in the beam path and the phase-contrast application
can begin. In order to return to the bright field application, you must pull the PH slider
out of the condenser, so that the beam can pass the condenser without being
affected by the PH slider.
The PH objective has a PH ring in its lens system, just like the PH slider. Due to their
size on one hand and their positioning on the other, these two rings must be aligned
to one another in the beam path. The position of the ring in the objective cannot be
altered, that of the ring in the slider however can be. Before starting the phase-
contrast application you have to check if this alignment is given. For this you must
install the centring telescope to the tube connector instead of a standard eye piece
and look through it (
The appearing image can be focussed by firstly loosening the
locking screw on the centring telescope, pull out the front part of the centring
telescope to the correct position and finally retightening the locking screw
) .
When installing the centring telescope instead of one of the eyepieces there is
appearing an image of a white (slide) and a black (objective) ring in the field of view
(
see illustration ). The black one is located centrally and the white one possibly shifted
to the side. In case of a shift, the position of the white ring has to be adjusted in order
to effect an exact overlapping of both rings by means of the two adjusting screws of
the condenser.
Depending on the preferences of the user, using a green filter can produce a more
effective and pleasant image. To achieve this, the green filter must be placed in the
ring bracket of the field lens.