Adjustment - Leica DM LSP Bedienungsanleitung

Adjustment

Objective centration
Objectives are centered by adjusting (43.14)
them with two Allen keys (1.3; 43.15) until the
optical axis of the objective (and therefore the
centre of the image) matches the axis of rotation
of the specimen stage (41 and 42). When an
objective is centered correctly, a focused speci-
men area does not drift out of the field of view
when the stage is rotated. A specimen point in
the center of the crossline therefore does not
change positon during a complete rotation of the
stage. It is a good idea to use a specimen with
plenty of contrast and detail for the objective
centration.
Disengage the analyser and the Bertrand lens
(43.3; 43.4). Greatly narrow the aperture
diaphragm (43.7). Insert the two objective cen-
tering keys above the objective (43.14) you want
to center. Focus the specimen. There are two
similar ways of centering objectives:
Method I (Fig. 41)
Rotate the stage and note the point on the speci-
men that remains stationary. This point corre-
sponds to the mechanical axis of rotation of the
stage.
Now move this prominent point of the specimen
to the centre of the crosslines with the two cen-
tering keys. Rotate the stage and fine-adjust the
centration if necessary.
Fig. 41
Centration method I
Method II (Fig. 42)
Move the prominent point on the specimen (42a)
to the centre of the crossline M. Rotate the stage
until the point on the specimen is furthest away
from the centre of the crosslines M (position A,
Fig. 42b). Point A (= maximum distance of the
specimen point from the centre) may even be
outside the field of view. Turning the centering
keys, adjust the image until the specimen point A
is midway (= pos. B) between pos. A and the
centre of the crosslines M (42c). Move point A to
M and check that A stays at M when the stage is
rotated (42d). Repeat the centering process if
necessary.
Each objective must be centered separately. If
an objective is screwed out of the nosepiece,
e. g. for cleaning, and screwed back in the same
place, is centration is more or less retained.
The centering keys are then stored in the two
receptacles on the stage bracket (43.15).
M
A
a
Fig. 42
Centration method II
M M
B
A
b c
M
B
A
d
7