12.5 Use of aperture diaphragm (AS)
The numerical aperture value (N.A.) of the aperture diaphragm
affects image contrast. Increasing or decreasing this value ac-
cording to the numerical aperture of the lens changes the resolu-
tion, contrast and depth of field of the image.
1. Move the aperture ring ④ (Fig. 24) to open or close the dia-
phragm to the desired position.
•
For low-contrast specimens, set the numerical aperture
value to approximately 70%-80% of the objective's N.A. If
necessary, remove an eyepiece and, looking into the empty
eyepiece holder, adjust the condenser ring until an image like
that in Fig. 19 is obtained.
12.6 Use of color filters
1. Insert the filter ① in one of the two slots ② placed in the
upper part of the reflected light illuminator. (Fig. 25).
Filter
Blue
Converts the source color temperature to
Increases the contrast in black and white
Green
Yellow
Contrast filter for the observation of wafers
Frosted white
Reduces lighting irregularities by creating a
12.7 Use of polarized light
1. Insert the polarizer all the way into the optical path. (Fig. 26)
2. Insert the analyzer all the way into the optical path. (Fig. 27)
Application
daylight
photography
and semiconductors
homogeneous field of view
①
Page 16
④
F ig. 24
F
ig. 24
②
F ig. 25
F
ig. 25
F ig. 26
F
ig. 26
F ig. 27
F
ig. 27