Aperture Diaphragm - Nikon eclipse lv150 Instruction Manual

8

Aperture Diaphragm

Remove one of the eyepieces. Operating the aperture diaphragm
open/close lever will change the size of the aperture diaphragm
as seen within the objective's exit pupil in the eyepiece tube.
Generally, the aperture diaphragm should be adjusted to about 70 to
80% of the numerical aperture of the objective.
About the aperture diaphragm
• Since the aperture diaphragm is for adjusting the numerical aperture of the illumination
system, this diaphragm is related to the resolution, contrast, and depth of focus of the optical
image.
• The diaphragm image may not appear in the case of samples with low reflectivity. In this case,
change to a sample with a near-polished surface.
• For the illuminator LV-UEPI, the aperture diaphragm centering has been adjusted at the
factory and does not need to be adjusted.
Centering the aperture diaphragm (for the LV-UEPI2 only)
When the illuminator LV-UEPI2 is used, the aperture diaphragm centering can be adjusted through
these steps:
1 Focus on the sample with the 10x objective by following the steps of bright-field microscopy
(p.16, 17).
2 Remove one of the eyepieces. Check that the aperture diaphragm image is seen within the
objective's exit pupil in the eyepiece tube.
3 Lower the aperture diaphragm open/close lever to reduce the field diaphragm opening.
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 center of the
objective's exit pupil.
5 Use the diaphragm open/close lever and centering screws so that the aperture diaphragm
image is inscribed in the objective's exit pupil.
6 When starting observation, adjust the aperture diaphragm open/close lever so that the
aperture diaphragm image is 70 to 80% of the numerical aperture of the objective. (Adjust the
aperture diaphragm for each objective.)
32
Image of aperture diaphragm
Objective's exit pupil
Objective's exit pupil
70 to 80
100
Aperture diaphragm