Nikon Epiphot 300 Manual page 37

(11) Put polarizer and analyzer in the optical path.
(12) Attach an appropriate Nomarski prism to the
revolving nosepiece. Push the prism slider until it
reaches the limit. Rotate the nosepiece to bring
the prism in the optical path.
Nomarski prisms and objectives are to be used in
pairs. Check the indication on each Nomarski
prism to select a correct prism that matches the
objective. (The alphabetical indication found
next to the NA indication on an objective should
be identical to that on a Nomarski prism.)
Indication on
Nomarski prism
A
B
C
E
The indication such as "S 1 ", "S2" found before
the alphabetical indication on each Nomarski
prism shows the difference in the shearing
amount. You may be able to increase the image
contrast by exchanging the Nomarski prism to
those having the shearing amount that matches
the specimen. (Although, this may not work on
some specimen.)
(13) Align the dot index (•)on the polarizer rotation
ring with the triangle index ( ► ) of the polarizer
slider to attain the crossed Nicols position. (The
direction of the analyzer has been factory­
adjusted.)
(14) Adjust the brightness with ND filters and lamp voltage adjustment.
*
The resulting dark background (without the first order red compensator in the optical path),
produces an interference image similar to that obtained through brightfield phase contrast
observation. The gradual rotation of the polarizer changes the background to the so-called
sensitive gray for optimal image contrast. This image now appears in relief. much like the
shadowing observed with an electron microscope, and clearly shows the phase contrast
distribution over the entire specimen like a 'bird's eye' view.
The insertion of the first order red compensator into the optical path when the background is dark
(that is, at the time of the crossed Nicols position), turns the background to sensitive red-violet for
optimal color contrast. Changing the background to sky-blue color by the rotation of the
polarizer, with the first order red compensator still in the optical path, produces an interference
image similar to that obtained through darkfield phase contrast observation. For a specimen
with considerable phase contrast diff e rences caused by its uneven surface, the background can be
changed to another color to achieve the desired contrast.
Corresponding Objec:tives
BD Plan DIC 10x/20x/50x/100x
BD Plan DIC 5x
ELWD BD Plan DIC 50x/100x
ELWD BD Plan DIC 20x
I
s:
c'i
::,:,
0
(/)
.,,
(')
0
.,,
c'i
::,:,
0
(")
m
0
C
::,:,
m
30