29
9. Measurement of solid sample
Note:
Fig. 9-5
(2)-4 Lighting
For measuring Refractive Index of film
sample, make sure to use a D-line (589
nm) light source such as a sodium
lamp and so on to illuminate the
sample stably with a monochromatic
light
as
well as to prevent
measurement from getting influenced
by diffused light and diffusion reflection.
Open the secondary prism completely
and light of the lamp horizontally
penetrates the sample through the
front side (lighting side).
When
using
D-line
lamp
for
measurement,
set
the
color
compensation knob to "30" of scale
value of the color compensation
knob NAR-2T.
Sodium lamp
Main prism
Film
Test piece
Contact
liquid
Eyepiece
When the refraction view is not
clear
because
of
intense
illumination of the lamp, shake
the light with white thin paper
or tissue paper by inserting it
between the lamp and test
piece.
Note:
Note:
In the case of using LED lamp
(approximating to wavelength of
D-line) of NAR-2T, turn the color
compensator
knob
and
stop
turning when the boundary line
becomes
neither
reddish
nor
bluish.
