15
A12.0910
3-11 Adjust the Aperture Diaphragm
The aperture diaphragm decides the numerical aperture
of the illumination system. If the N.A. of illumination
system matches with the N.A. of the objective, it can
obtain better resolution and contrast, and increase the
depth of field.
Adjust the aperture diaphragm adjusting ring
③
to
control the size of diaphragm. Take off the eyepiece if
necessary, observe from the eyepiece tube and adjust
the aperture diaphragm adjusting ring
③
until see the
figure as shown in Fig. 23 (see Fig. 23&24).
Use of scale: set the scale of condenser N.A. to the 80%
value of objective
④
N.A (see Fig.24).
In actual use, adjust the aperture diaphragm according
to the size of the sample image contrast, until it’s
comfortable for observation and the contrast is good.
3-12 Use the Color Filter
The color filter can make the background light more
suitable and strengthen the image contrast.
When an external color filter is used, put a diameter
45mm filter into the groove of the condenser base
①
(See Fig. 25).
★
There are four colors of filter selectable: blue,
green, yellow and white.
★
Place the rough side of filter downwards.
When an internal color filter is used, pull the pole
②—
⑤
to the outmost, the filter will be moved into the
light path. Otherwise, push the pole into the innermost,
the filter will be moved out of the light path. (See Fig.
25)
Fig. 24
Fig. 25
