MICROFILM SCANNING APPARATUS
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 eff...
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| Format: | Patent |
| Sprache: | eng |
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| Zusammenfassung: | 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. |
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