ZEISS
OPERATION
Axio Imager 2
Illumination and contrast methods
190
430000-7544-001
01/2016
The values for a and b (see Fig. 210) are
determined using the eyepiece reticle or the
micrometer eyepiece.
If you are working with white light (without
interference filter),
λ
= 550 nm must be used.
When using interference filters, their center
wavelength applies.
The measured path difference is aperture-
dependent and decreases with increasing
illumination aperture.
Accordingly, the following correction values must be taken into account depending on the objective
used:
Objective
Correction factor k
5x/0.15
1.0057
10x/0.25
1.0161
10x/0.30
1.0236
20x/0.4
1.0436
20x/0.50 and 50x/0.75
1.0718
50x/0.60
1.1111
50x/0.75 and 100x/0.75
1.2038
50x/0.80
1.2500
50X/0.90 and 100x/0.90
1.3929
100X/0.95
1.5241
Table 1:
Aperture-dependent correction
Example:
a = 11 mm
b = 5 mm
λ
= 550 nm
Objective 20x/0.50
nm
134
mm
22
0718
.
1
mm
5
nm
550
a
2
k
b
d
=
⋅
⋅
=
⋅
⋅
λ
=
Fig. 210
Interference fringe pattern
