Nikon ECLIPSE E400 POL Instructions Manual page 28

Ш 2. P-CQ Quartz wedge
The P-CQ quartz wedge is used by inserting it into the
slot of the intermediate tube in place of the P-CL 1/42 &
tint plate. The quartz wedge is engraved with a scale
and can be used for rough measurement of retardation in
the range of 12-62.
It is normal to bring the top lens of the condenser into the optical path when observing at a
magnification of 10x or greater. Measuring the retardation or evaluating by interference
color, however. swing out the top lens even for a magnification of 10x stop down the
condenser aperture diaphragm or higher (with the aperture diaphragm fully opened), and
illuminate with light that is as parallel to the optical axis as possible.
1 Determination of Extinction Position
Rotate the stage with the specimen under the crossed Nicols to find the direction where
part of the specimen to be measured appears darkest.
2 Determination of Subtraction Position
Rotate the stage 45? from the extinction position to the diagonal position (direction whe
the specimen appears brightest). Insert the P-CQ quartz wedge into the slot of the
intermediate tube and confirm that the interference color of the section of the specimen
measured changes toward the lower order side. If the interference color changes toward
higher order side, rotate the stage another 90%
3 Measurement
Move the section of the specimen to be measured
to the center of the crosshairs of the eyepiece.
Next, slide the P-CQ quartz wedge along the slot
and observe that the interference color
sequentially changes. Stop sliding the quartz
wedge where the dark stripe covers the section of
the specimen to be mi
from the q
asured. Reading the value
artz wedge scale at that time can make
rough measurement of retardation
Retardation can be measured even more
curately by using the P-CS Sénarmont
compensator in combination with the P-CQ quartz
wedge.
Read the scale
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