Oil/Water Immersion - Nikon Eclipse Ni-E Instruction Manual

14

Oil/Water Immersion

Oil immersion
An objective with an "Oil" marking is an oil-immersion objective.
An objective of this type is to be used with designated
non-fluorescent immersion oil applied between the sample and
the tip of the objective.
For maximum performance, an oil-immersion objective with a
numerical aperture of 1.0 or larger should be combined with an
oil-immersion achromat aplanatic condenser.
When using an oil immersion condenser, apply the designated
non-fluorescent immersion oil between the slide glass and the
tip of the condenser lens. Oil immersion condensers are
aberration-corrected under the assumption that they will be
immersed in oil. For this reason, oil must be applied between
the slide glass and the condenser, regardless of whether the
objective is an oil immersion type.
To apply oil to the condenser, remove the specimen from the
stage, lower the condenser by rotating the condenser focus
knob, and then drip oil onto the tip of the condenser.
Use as little oil as possible (just enough to fill the space between the tip of the objective and the specimen or between the
tip of the condenser and the specimen), taking care not to form bubbles. Too much oil will result in excess oil flowing onto
the stage and around the condenser. While oil immersion condensers have a dimple for catching oil that has overflowed,
excessive oil may flow out of the dimple and contaminate the DIC module and/or the inside of the condenser. On the other
hand, use of insufficient oil may result in air entering between the slide glass and the condenser, degrading the
performance of the condenser.
Do not apply immersion oil to a "Dry" condenser.
The universal condenser is designed for dry use. Do not apply immersion oil. Be careful not to apply immersion oil
between other dry condensers and a specimen when used.
Air bubbles in the oil
Any bubbles in the immersion oil will degrade image quality. Be careful to prevent bubbles from forming. To check for
air bubbles, fully open the field diaphragm and aperture diaphragm, remove the eyepiece, and examine the exit pupil
(bright round section) of the objective inside the eyepiece tube. If it is difficult to ascertain the presence of bubbles,
attach a centering telescope, and then look for air bubbles while turning the eyepiece section of the centering telescope
to adjust the focus. If you detect bubbles, remove them by one of the following methods:
 Turn the revolving nosepiece slightly to move the oil-immersed objective back and forth once or twice.
In the case of the condenser, gently turn the condenser focus knob to move the condenser up and down slightly.
 Add more oil.
 Remove the oil and apply new oil.
Cleaning the oil
Oil remaining on the oil-immersion objective or adhered to the dry-type objective will significantly degrade image
quality. After use, thoroughly wipe off all oil, and make sure that no oil remains on the tips of other objectives.
Additionally, carefully wipe off the oil from the condenser.
Use petroleum benzine to wipe off the immersion oil. For optimum results, Nikon recommends cleaning with absolute
alcohol (ethyl or methyl alcohol) after cleaning with petroleum benzine.
If petroleum benzine is unavailable, use methyl alcohol alone. When using just methyl alcohol, note that surfaces will
need to be wiped repeatedly to ensure complete removal of the immersion oil. (Usually, three or four times should be
sufficient to clean the lens.)
CAUTION
 Petroleum benzine and absolute alcohol used for cleaning off the immersion oil are highly flammable. Be careful
when handling these materials, particularly around open flames or when turning the power switch on or off.
 Follow the instructions provided by the manufacturer when using absolute alcohol.
Chapter 3
Individual Operations
115
Oil immersion of the objective