OPERATION
Axio Imager
Illumination and contrast methods
Carl Zeiss
M70-2-0020 e 06/2009
430000-7344-001
153
4.9.4
Setting transmitted-light differential interference contrast (DIC)
(1) General
principle
The transmitted-light DIC method is a contrast method alternative to polarization allowing contrasty, 3D
presentation of transparent specimen details.
The light linearly polarized by a polarizer is split into two partial beams by a birefringent prism. The beams
pass two closely adjacent places of the specimen and thus are subject to different path differences
caused by differences in refractive index and thickness of the specimen. Afterwards, both partial beams
are recombined in a second birefringent prism and, after having passed the analyzer, they have the same
vibration direction. Thus, both partial beams can interfere with each other in the intermediate image with
the different path differences being converted to different gray values (intensities). A compensator
λ
(full-
wave plate) then converts the gray values to colors.
(2) Instrument
configuration
−
Objectives offered together with the DIC equipment, e.g. Plan-Neofluar objectives
−
Objective nosepiece with slot for DIC slider, matching the objectives used
or
motorized four-position modulator turrets in combination with analyzer module DIC ACR shiftfree for
transmitted light
−
Condenser with turret disk containing DIC prisms (DIC I, DIC II, DIC III)
−
Analyzer module D DIC P&C (424921-0000-000) in reflector turret. Only this module may be used on
the Axio Imager as it provides a homogeneous field of view in combination with the special condenser
modules I, II and III.
−
Preferably a rotary mechanical stage
(3)
Adjusting the transmitted-light DIC with DIC slider and DIC prism in the condenser turret
•
On the nosepiece, swivel the objective (4-120/
4
) suitable for DIC into the light path. Push the
corresponding DIC slider (4-120/
1
) into the slot of the respective objective position. Make sure the DIC
slider snaps in reliably.
•
On the reflector turret (4-120/
3
), swivel in the analyzer module D DIC (4-120/
8
).
•
Swivel in the suitable DIC prism I, II or III (digit label on turret disk of condenser (4-120/
6
)).
•
Adjust luminous-field diaphragm and aperture diaphragm (4-120/
5
) in accordance with the rules of
KÖHLER illumination.
•
Turn knurled screw (4-120/
2
) on DIC slider (4-120/
1
) to adjust optimum contrast. When adjusting the
DIC slider symmetrically around its mid-position, the specimen details can be imaged in such a way
that they appear three-dimensionally as if they were raised or dented.
•
If desired, you can push the compensator
λ
7
) into the slot for the analyzer slider above the
nosepiece to obtain colored DIC contrast.
For 63x objectives, in addition to the DIC sliders HR (High Resolution), another type, HC (High Contrast),
is available, which is to be used depending on the type of specimen and examination to be performed.
