Olympus U-CBE Instructions Manual page 12

U-CBE, U-CTB
Fig. 3
9
3
Measuring Retardation
} If an interference filter (IF 546 or IF 550) is available, use it
in this measurement.
1. Place an interference filter in the filter holder of the microscope
frame.
# If an interference filter is used, multiple black dots or
fringes will be visible. Use the black dot or fringe that
is visible when the interference filter is not used.
To identify this dot or fringe, check the position of
the black dot or fringe without using the filter before
engaging it, then engage the interference filter and
confirm the same black dot.
2. Rotate the compensator knob to the position where the
measured portion on the center of the field of view is darkest
(Fig. 3) Find the angle at this position by totaling the readings
of scales 1 and 2. → θ
3. Rotate the compensator knob in the opposite direction and
read the angle of the position with which the measured
portion on the center of the field of view is darkest in the
same manner as in step 2 above. → θ
4. Repeat steps 2 and 3 several times, obtain the mean value
of θ , θ , and that of θ
1 1
value θ using the following formula:
1
2
, θ
, and finally find the overall mean
2 2
│ θ – θ │
θ =
1 2
2