Field Service Manual December 2003
Page 183 of 276
The Abbe König prism
The beams go through the Abbe König prism: to expose, the beam
pattern must be tilted. A mechanical rotation of n degrees of the prism
results in an image rotation of 2 x n degrees. The SSIPRO-board takes
care of the delays between the beams (they are delayed independently
of each other).
All beams converge in 1 point, the telecentric point.
The doublet
The doublet is the focussing lens. The optical resolution depends only
on the focal length f of the doublet. When the TC-point is at f distance
from the doublet, the beams leave the doublet in parallel and
are focussed at f after the doublet. By moving the doublet, the film
plane is moving.
The optics is designed for a fixed spot size: the focussed spot 7 um.
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