Microfilm scanning apparatus
AssigneeWicks and Wilson Limited
InventorRobert A. D. Brash
Life of this patent
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Abstract
A microfilm scanning apparatus of the entrance scanner type has a microfilm, normally mounted in an aperture card which is mounted on a curved surface of a plano-convex cylindrical lens platten. The microfilm is scanned in one direction by radiant energy produced by a laser diode, scanning being effected by facets on a bevelled edge polygon mirror which is rotated by a motor. So as to perform scanning in a direction orthogonal to the scanning produced by the mirror, the platten is driven by a stepping motor. The curved surface of the platten is arranged to coincide with the loci of the focus of the scanning beam as the mirror rotates. By the provision of a curved surface platten, a simple spherical lens system may be interposed between the mirror and platten.
Claims11
A microfilm scanning apparatus of the entrance scanner type including radiant energy producing means, a rotatable polygon mirror for receiving a radiant energy from the producing means and scanning said radiant energy across a microfilm, a platten having an arcuate surface for supporting said microfilm thereon, said arcuate surface coinciding with the loci of the focus of the scanning radiant energy, and said platten being in the form of a plano-convex lens, the plane side of the platten being located adjacent the polygon mirror.
An apparatus as claimed in claim 10 wherein the platten is made from transparent plastics.
Dependencies are inferred from the claim text.