Nikon ECLIPSE E200 POL Instructions Manual page 30

16
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 1/4λ & tint plate. The quartz wedge is
engraved with a scale and can be used for rough
measurement of retardation in the range of 1λ-6λ.
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, you need to stop down the
condenser aperture diaphragm, or to swing out the top lens even for a
magnification of 10x or higher (with the aperture diaphragm fully opened), to
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 the
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
where 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 to be measured changes toward the
lower order side. If the interference color
changes toward the 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 measured. Reading the value from the
quartz wedge scale at that time can make a
rough measurement of retardation.
Retardation can be measured even more
accurately by using the P-CS Sénarmont
compensator in combination with the P-CQ
quartz wedge.
IV Microscopy (Detailed Procedure)
28
Insert here
Read the scale