A & Tint Plate; Accessories; Senarmont Compensator; Quartz Wedge - Nikon OPTIPHOT-POL Instructions Manual

VI.
ACCESSORIES
1. Senarmont Compensator
To be inserted into the compensator slot of the
intermediate tube "P" in place of the 1/4 A &
tint plate to measure the retardation with the
accuracy of the A unit. (Fig. 33)
Fig. 33
1)
Detecting of extinction position
Rotate the stage with the specimen under
the crossed Nicols to find out the direction
where the specimen part for measurement
appears darkest.
2) Detecting of subtraction position
Rotate the stage
45°
to bring it to the dia-
gonal position from the extinction position
and confirm that the interference color of
the specimen part for measurement changes
toward the lower order side by inserting
the 1/4 A
&
tint plate into the optical path.
If the color changes toward higher order
side, rotate the stage further by 90°.
2. Quartz Wedge
The quartz wedge is used instead of the 1/4 A
& tint plate that is in the compensator slot of
the intermediate tube "P". (Fig. 34)
With this wedge the retardation in the range of
1 A ~ 6 A can roughly be measured.
-"~
Fig. 34
1) Detecting of extinction position
Detect the position where the specimen
part for measurement becomes darkest by
rotating the stage under the crossed Nicols.
2) Detecting of subtraction position
Rotate the stage
45°
to bring it to the dia-
gonal position from the extinction position
and confirm that the interference color of
the specimen part for measu rement changes
toward the lower order side by inserting
the quartz wedge into the optical path.
If the color changes toward the higher
order side, rotate the stage further by
900
When the fi Iter G I F is used: A = 546nm
3) Measurement
Inserting the filter GIF into the filter
receptacle, replace the 1/4 A
&
tint plate
by the compensator.
Rotate the analyzer so as the specimen part
for measurement becomes as dark as possi-
ble.
Let the angle of the above analyzer rota-
tion be
eO
then the retardation R (nm) will
be obtained as follows:
where A
wave length of the
Iight used for the
measu rement
3) Measurement
By sliding the quartz wedge along the slot,
the interference color changes consequent-
ly.
The wedge sliding is to be stopped when
the specimen part for measurement comes
under the dark stripe, then compare the
interference color of the view field beyond
the specimen but under the same dark
stripe with the Interference Color Chart to
assume the amount of retardation.
If the view field is entirely filled with the
speci men arou nd the part to be measu red,
restrict the illumination of the view field
except around the part for measurement
by means of the field diaphragm, remove
the specimen away the optical path and
then compare the interference color with
the chart.