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5.0 PHASE CONTRAST OPERATION
5-1 IDENTIFYING THE COMPONENTS
5-1-1 Phase contrast objectives (fig. 22)
The magnifications of the optional phase contrast objectives are:
10X and 20X. These objectives are marked “PH”.
Mount the objectives on the turret using the same procedures as the
standard objectives (3-2-2).
5-1-2 Phase contrast slider (fig. 23)
Adjustable phase slider.
● The light ring is pre-centered when the microscope leaves the facto
-
ry. It should therefore need no further adjustment. If a recentering is
needed, it can be performed via the two side bolts.
● The 10X/20X light ring (1) must be used with the 10X,20X phase
contrast objectives, the 40X light ring (2) with the 40X and the ope
-
ning (3) is used for bright field.
5-2 SETUP AND USE
5-2-1 Installing the phase contrast slider (fig. 24)
1.
Insert the slider into the illumination system, printed face up.
2.
Pull the slider into the desired position, to the click stop.
3.
When in phase contrast observation, keep the aperture diaphragm
adjustment lever on the “O” (open) position.
5-2-2 Centering the ring (fig. 25)
► Usually this operation is not needed. If necessary, please pro
-
ceed with the following steps:
1.
Place a specimen on the stage and focus it.
2.
Take out the eyepiece from the tube without the dioptric adjustment,
and replace it with the centering telescope (CT).
3.
Check that the phase ring and the objective correspond, and that
both are steadily set on a click stop.
4.
Use the CT to focus on the light ring’s image (5) and the phase con
-
trast ring’s image (2). If the light ring’s image is not sharp, adjust the
CT’s eyepiece until you can see a clear image of the light ring (2).
5.
Adjust the bolts of the two centering holes in the phase contrast
slider using a screwdriver until the light ring center and the phase
contrast ring center coincide.
6.
The 10X and the 20X phase contrast objectives use the same ring
on the phase contrast slider. The coincidence of the light ring center
and the phase contrast center must be verified with both objectives.
►
If the light ring is centered incorrectly, the contrast will be seve
-
rely impaired.
► The phase ring may need recentering during and after observa
-
tion of very thick specimens.
► The phase ring may show an apparent misalignment if the co
-
ver glass is not flat.
Figure 22
Figure 23
1
2
3
Figure 24
1
2
Figure 25