Nikon Eclipse LV100DA-U Instructions Manual page 53

Aperture diaphragm
The aperture diaphragm controls the numerical aperture
of the illumination system, closely related to the
resolution of the optical image, contrast, and depth of
focus. Generally, the aperture diaphragm should be
adjusted to about 70 to 80% of the numerical aperture
of the objective.
The aperture diaphragm of the LV-UEPI2A is
electrically driven, thus the size of the aperture
diaphragm can be controlled by the A.S. switch on the
control panel.
Remove one of the eyepieces, and then adjust the
aperture diaphragm opening while observing the exit
pupil of the objective (the bright area when the aperture
diaphragm is fully opened) in the eyepiece tube.
When the reflectance of the specimen is low, the
diaphragm image may not be seen. In this case, change
to a specimen of a near-polished surface.
Centering procedure for the aperture diaphragm
1 Follow the procedure described in Pages 15 and 16 for the bright-field microscopy under the
episcopic illumination, and focus on the specimen with the 10x objective.
2 Remove one eyepiece, and verify that the aperture diaphragm image is seen in the pupil of
the objective in the eyepiece tube.
3 Stop down the aperture diaphragm with the A.S. switch on the operation panel.
4 Insert a hexagonal wrench into the aperture diaphragm centering holes on both sides and turn
the internal adjustment screws to bring the aperture diaphragm image to the pupil center of
the objective.
5 Operate the A.S. switch and the centering screws so that the aperture diaphragm image
inscribes the pupil of the objective.
6 When starting observation, adjust the A.S. switch so that the aperture diaphragm image is 70
to 80% of the numerical aperture of the objective. (Perform this adjustment for each
objective.)
When the interlock control of LVSetup is enabled, the aperture diaphragm can be
automatically adjusted to the registered condition to match the objective and the microscopy
selected.
To bring the aperture diaphragm to the registered conditions, hold down the EPI switch and
the DIA switch for two seconds or longer. A short beep sounds to notify that the aperture
diaphragm and the light quantity are restored to the registered conditions.
NIS-Elements compatible
Image of aperture diaphragm
Objective's exit pupil
III. Operation of Each Part
Pupil of the objective
70% to 80% 70% to 80% 70% to 80%
100% 100% 100%
Aperture diaphragm
EP I
EP I
OB J.
DIA
CU BE
A.S .
DIA
Adjusting the aperture diaphragm for the
episcopic illumination
Close Open
A.S.
51