10
Polarized light observation
In order to correctly use the polarized light, it’s necessary to perform a setting for “light extinction”:
1.
Remove from the optical path the sample, retardation plates, etc...
2.
Insert the 10x objective.
3.
Insert in the optical path the analyzer filter and rotate the rotation scale (8) in correspondence to
position “0”.
4.
Put the angular scale (9) of the polarizer filter to “0” position.
5.
Loosen the lock screw of the polarizer and, looking into the eyepieces, rotate the scale of the polarizer until
you obtain the complete extinction of the light (totally dark).
6.
Then lock the polarizer screw.
Bertrand lens
Bertrand lens is employed in conoscopic observation mode (lens inserted) or orthoscopic mode (lens not in-
serted).
Orthoscopic observation
The path of the polarized light is parallel to the optical axis, thus allowing the observation of the optical charac-
teristics of the specimen. You can use objectives from 4x to 100x.
1.
Remove the Bertrand lens out from optical path.
2.
Insert the analyzer filter using the proper lever (12) and look at the sample.
3.
Insert a retardation plate (11) pushing it completely inside the slot under the head.
To remove the plate from the optical path, pull it outward till the first click.
Conoscopic observation
1.
Use objectives from 20X to 100X.
2.
Insert the analyzer using the proper lever (12) and put it in the extinction position.
3.
Insert the Bertrand lens.
4.
Insert the objective of choice (from 20X to 100X).
5.
Open the aperture diaphragm.
6.
It’s possible to center the conoscopic image adjusting the screws (10) placed under of the head.
In this manner it’s possible to look at the conoscopic images that form on the back focal plane of the objective. If
the peripheral part of the image is too dark, you can just move the condenser vertically to find the optimal posi
-
tion for the illlumination.
Retardation plates
Retardation plates (1 lambda, corresponding to 530nm or Red 1° order, ¼ lambda corresponding to 137nm, and
quartz wedge) are used to make the polarization analysis more precise and refined.
Insert or remove the plate in the optical path of the microscope by pushing it into the slot (11) under the head.
Retardation plates have no visible effect when used in normal brightfield light.
IMAGE CONOSCOPIC
