101
Possible errors, brightfield, darkfield, ICR
Fall-off of focus, one-sided:
Sample surface not aligned at exactly 90
°
to the
optical axis.
Sample has round edges.
Stage not clamped tight.
Fall-off of focus on both sides:
Sample surface greatly inclined.
Fall-off of focus, partial:
Pronounced relief zones in the sample beyond
the range of the depth of focus of the objective.
Fall-off of focus, concentric:
Sample surface is round.
Image is unusually flat:
Poor sample quality.
Fingerprints or dirt on front lens of objective.
Sample covered by other layers.
Illumination aperture not exactly matched to the
sample (Close aperture).
Objective in use is not suitable for reflected light
(see DELTA optics objective data sheet).
Inhomogeneous image illumination:
Lamp not adjusted.
Sample not aligned flat.
For bright-/darkfield:
Oblique illumination lever not in exact position.
Diaphragm module not in exact position.
Polarizer/analyser slide not exactly positioned.
Tube beamsplitter at incorrect setting.
For ICR interference contrast:
IC prism in light path.
Wrong IC prism engaged.
Polarizer discoloured due to overheating.
Incorrect polarizer setting (see page 100).
Object marker
The object marker is screwed in place of an
objective (not illustrated). When rotated, a
diamond is lowered onto the coverglass or
object surface, where circles of variable radii
can be scribed to mark objects.
Multi-viewing attachment:
see separate manual.
