Leica DM R Serie Mode D'emploi page 80

Survey observation
Put a transmitted light specimen on the p olar-
izer. Swing in the condenser top and focus
through the condenser with a low-power
objective, e.g. 5x. Even though this method does
not claim to
performance, it allows extremely fast scanning
of series of specimens, cf also macro device on
p. 102.
λ/4 and λ compensator, Quartz wedge
Depending on the microscope model, the quarter-
and whole-wave compensators are either
integrated under the condenser (27.6), or, in the
case of polarized light microscopes, in the 8-
position disc (17.6) (vibration direction λ is dia-
gonal ) inserted in the tube slot (54.13). The
tube slot is closed by a spring-loaded dust
protection flap.
200
– λ
400
600
800
+ λ
1000
1200
1400
1600
80
produce good imaging
Black
Lavender gray
Gray blue
Yellowish-white
Vivid yellow
Red-orange
λ
Deep red
– –
4
Indigo
λ
Sky blue
+ –
4
Greenish blue
Light green
Pure yellow
Orange red
Dark violet red
Indigo
Greenish blue
Sea green
Greenish yellow
Flesh color
Crimson
Matt purple
The analyser IC/P (30.5) has a whole-wave
compensator on one side, which is activated by
inserting the analyser the other way up.
When a compensator is engaged, the phase
difference is increased or decreased (see
Fig. 56).
The vibration direction γ (i.e. corresponding to
the refractive index n
refractive index) can be determined from the
colour changes. The quartz wedge (57.7) allows
variable colour shifts on the polarized light
microscope.
Circular polarization
Only with polarized light microscopes in
transmitted light:
Birefringent objects exhibit four extinction
positions for one stage rotation. Particularly
when scanning a large number of specimens,
some of the birefringent objects will always
happen to be at the extinction position. Circular
polarization is used for simultaneous obser-
vation of the interference colours of all objects:
Remove the specimen from the light path or find
an empty area of the specimen. Cross the
polarizers exactly – they must also be exactly at
the N – S/E – W positions, i.e. the analyser must
be set either at the 90° or 0° position (54.3).
Fig. 56 Interference colours in relation to phase difference,
or to thickness and colour change for the addition and
subtraction position of a whole-wave and a quarter-wave
compensator
with the greater
γ