Zeiss Axiolab A Especificaciones descargar pdf (Pagina 100)

OPERATION

Carl Zeiss Lighting and contrasting method in transmitted light Axio Lab.A1

100 430037-7144-001 04/2013

With optically biaxial crystals, the cross resolves into two dark hyperbola branches (the so-called

isogyres) depending on stage rotation, which are surrounded by colored interference patterns

depending on the amount of birefringence and specimen thickness (suggestive of the figure "8").

Inserting a compensator O (473704-0000-000) or O/4 (473714-0000-000) or a wedge compensator 0-4 O

(000000-1140-663) in the compensator slot with the initial state of the axial figure being as illustrated in

Fig. 4-18 results in the following changes in color shown schematically (blue and yellow areas) to the axial

figure, thus allowing differentiation in "optically positive" and "optically negative".

Optically uniaxial Optically biaxial

Positive Negative Positive Negative

O-Plate

(white o blue

o yellow)

+ = blue

– = yellow

Quartz wedge

(Direction of motion

at insertion)

Ò Direction of

Ó movement

O/4 plate

(position of black

spots)

Fig. 4-18 Determining the optical character

In the case of less favorable sections in which the cross-hair center is optically uniaxial or the isogyres are

optically biaxial specimens outside the objective pupil, an assessment is possible as follows:

x If the black isogyres are straight and they run parallel to the pupil (in relation to the cross-hairs), the

specimen is optically uniaxial.

x If the black isogyres are curved lines which wander on a circular path through the pupil, the

specimen is optically biaxial.

Paying appropriate attention, also such axial figures not illustrated in Fig. 4-18 can be interpreted.

Axial figures can often be better displayed with circular polarization. Particularly the axis angle

of optically biaxial specimens (quasi distance between the isogyres) can be determined more

clearly. The optical character can also be determined. For this purpose the compensator O

(6 x 20), arranged in the compensator slot, is used.

Two storage compartments for 6x20 slides are located on the reverse side of the conoscopy

stand.

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Zeiss Axiolab A Especificaciones Pagina 100