Chapter 3 Individual Operations
3.14 Oil Immersion Operation
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3.14
Oil Immersion Operation
Objectives marked “oil” are oil-immersion type
objectives. These objectives are used with
immersion oil (option) between the specimen and
the tip of the objective.
Bubbles in the oil will adversely affect the viewing
of the image. 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 pupil (bright round
section) of the objective inside the eyepiece tube.
If it is difficult to ascertain the presence of bubbles,
place the Bertrand lens into the optical path. Then,
check for air bubbles while turning the Bertrand
lens focus ring to change the focus. (P.48):
•
Turn the 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.)
•
Apply more oil.
•
Remove the oil and replace it with new oil.
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). If too much oil is applied, the
excess oil will flow onto the stage or around the condenser.
Wipe off oil
Any oil remaining on the oil-immersion objective or adhering to the dry-type objective will
noticeably degrade image quality. After use, thoroughly wipe off all oil, and make sure that no oil
remains on the tips of other objectives. Oil on the condenser should also be wiped away carefully
after use.
Use petroleum benzine to wipe off immersion oil. For optimum results, we recommend following
up petroleum benzine with absolute alcohol (ethyl or methyl alcohol).
If petroleum benzine is unavailable, use methyl alcohol alone. However, methyl alcohol does not
clean as well as petroleum benzene, it will be necessary to wipe the surface repeatedly. (Usually,
three or four times are sufficient to clean the lenses.)
When using petroleum benzine or absolute alcohol, always follow the
instructions provided by the manufacturer. These liquids are highly
flammable and must be kept away from flames and sparks.
CAUTION