OPERATION
Carl Zeiss
Illumination and contrast methods
Axio Imager
168
430000-7344-001
M70-2-0020 e 06/2009
(3)
Setting reflected-light brightfield according to KÖHLER
−
The microscope has been started properly as described in Section 3.
−
The microscope has been switched on.
•
Switch on the halogen lamp for reflected light using the reflected-light/transmitted-light toggle switch
(4-1/
36
) on the microscope stand.
Depending on the existing equipment, the microscope contains a 6x20 compensator mount or a 4-
position modulator turret for setting the contrasting techniques. The 6x20 compensator mount can be
used for both brightfield and darkfield. For C-DIC and TIC examinations, additionally the corresponding
6x20 slider is required. Refer also to Section 4.9.9.
The 4-position modulator turret has a combined brightfield/darkfield position (
H/D
) as well as three
additional positions for C-DIC (
C1
,
C2
) and TIC (
TIC
). Refer also to Section 4.9.10.
•
When using the 6x20 compensator mount, remove the 6x20 slider, if necessary. When using the 4-
position modulator turret, set the
H/D
position.
•
Swivel the reflector turret into brightfield position
H
.
•
Adjust light-intensity control (4-128/
5
) on microscope stand.
•
Place a contrasty reflected-light specimen on the stage.
•
Turn nosepiece (4-128/
7
) to swing in 10x objective (yellow ring, see also Section 2.5).
•
Use focusing drive (4-128/
6
) to focus on the specimen. In doing so, always focus away from the
specimen if possible to avoid any collision between objective and specimen.
•
Remove the reflected-light diffusion disk. Turn adjusting screws of HAL 100 halogen illuminator to
focus and center the image of the lamp filament in the exit pupil of the objective. For that, either pull
out the adjusting aid or remove one eyepiece from the binocular tube. Afterwards, push the adjusting
aid in again or reinsert the eyepiece. Move the reflected-light diffusion disk into the light path again.
•
Set the aperture diaphragm (4-128/
2
) in mid-position (about half open or closed) by turning its
knurled wheel.
•
Reduce the size of the luminous-field diaphragm (4-128/
4
) by turning its knurled wheel until it
becomes visible in the field of view (4-128/
A
).
•
Turn the focusing drive (4-128/
6
) to refocus on the edge of the luminous-field diaphragm (4-128/
B
)
and (using the SW 3 ball-headed screwdriver) turn the centering screws (4-128/
3
) until the luminous-
field diaphragm is concentric with the edge of the field of view (4-128/
C
).
•
Then, open the luminous-field diaphragm (4-128/
4
) so that it just disappears from the field of view
D
).
•
To set the aperture diaphragm (image contrast), remove one eyepiece from the binocular tube and
look into the tube with your naked eye or insert the auxiliary microscope in place of the eyepiece.
•
Center the aperture diaphragm with the centering screws (4-128/
1
) and, for specimens with average
contrast, adjust the size of the aperture diaphragm to about 2/3 to 4/5 of the exit pupil diameter of
the objective (4-128/
E
) by means of knurled wheel (4-128/
2
).
In most applications, this aperture diaphragm setting provides optimum contrast at almost ideal
resolution, and is therefore the best compromise for the human eye.
•
Finally, reinsert the eyepiece, refocus with the coaxial coarse and fine focusing drive (4-128/
6
) and
adapt the image brightness to the specimen to be examined.
Never use the aperture diaphragm to control the image brightness, but use the light intensity
control (4-128/
5
), or swivel attenuation filters of the 2-position filter wheels into the light path!
