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8.2 Phase-contrast units
The standardly supplied phase contrast unit of the microscopes of the series OCM-1
consists of a PH objective (20x), a PH slide, a centring telescope and a green filter.
Optionally PH objectives with a magnification of 10x or 40x are available.
To use this, you need to place the PH objective into the beam path and push the PH
slide (the writing facing up) into the appropriate slot on the condenser.
The slide must be placed in a way that the one of the three snap in positions, which
suites the objective magnification, is located in the beam path.
A PH objective has a PH ring in its lens system, just like the individual positions of the
PH slides. Due to their size on one hand and their positioning on the other, the two
related rings must be aligned to one another in the beam path. The position of the ring
in the objectives cannot be altered, that of the rings in the condenser disc however can
be.
In case of a not optimum positioning of one of the ring pairs, the adjustment needs to
be carried out as follows.
a. First adjust the microscope using bright field mode.
b. Move the PH slide to the required position (e.g. "20x").
c. Open the aperture diaphragm on the condenser to its maximum (slider to the left).
d. Bring the relevant PH objective (e.g. 20x) into the beam path.
e. Place the centring telescope onto one of the two tube connectors, in place of a
standard eyepiece.
f. Undo the fixing screw of the centring telescope and pull out (move) the front part of
the telescope, so that you can focus both phase rings in the field of view. Then
retighten the screws.
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OCM-1-BA-e-2211
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