Thickness Measurements - Leica DMLS Bedienungsanleitung

Example:
If 1.220 mm
corresponds to 50 divisions of the measure-
ment scale, the micrometer value is 1.220 : 50 =
0.0244 mm = 24.4 µm. For extremely low
objective magnifications it may be that only part
of the measurement scale can be used for
calibration.
Imp ortant: If using the magnification changer (36. 1 ):
Remember to take the additional magnification
value into consideration! We strongly recom-
mend you calibrate each objective separately
instead of extrapolating the micrometer values
of the other objectives from the calibration of
one objective. Measurement errors may occur if
the eyepiece is not pushed into the tube as far
as the stop.
Particularly large object structures can also be
measured on the stage with the verniers
(0.1 mm); the distance to be measured could be
calculated from a combined x and y measure-
ment.
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Thickness measurements

In principle, thickness measurements can be
carried out if both the upper and the lower
surface of the object can be clearly focused.
The difference in
(mechanical dual knob focusing: distance
between two divisions = ca. 3 µm) gives a value
for transmitted light objects that is falsified by
the refractive index of the object (which has
been "transfocused") and perhaps immersion
oil. The true thickness of the object detail
measured in transmitted light is given by the
vertical stage movement (focusing difference) d'
and the refractive indices n
of the medium between the coverglass and the
objective (air = 1).
n
o
d = d' n
i
Fig. 33 Scale of the graticule in the eyepiece (left) and image
of stage micrometer (right)
stage height setting
of the object and n
o
43
i