Importance

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Abstract

There is disclosed herein apparatus for positioning rows and columns of microimage frames imprinted on a cassetted filmstrip for projection and display. The filmstrip is longitudinally movable in incremental amounts through an elongated cassette passageway, the passageway having a transverse aperture for permitting projected light to pass through a selected portion of the filmstrip for enlarged and focused microimage display. The positioning apparatus includes a first and second transparent plates located in a cassette in the path of projected light on either side of the filmstrip, and an assembly for effecting separation of the first and second plates, the assembly also operable for clamping the selected filmstrip portion between the first and second plates in a filmstrip focusing plane. Cassette on which the first and second transparent filmstrip clamping plates are mounted and a viewer on which the assembly for effecting clamping and separation of the plates is mounted. The clamping-separation assembly is housed within an upper viewer module which is spaced from the base of the viewer. A filmstrip driving carriage is mounted for translation along tracks on the underside of the module in the space between the module and the base. The carriage secures the microfilm cassette for translation therewith relative to the path of the projected light to present a selected column of microimage frames into the path of the projected light, while the carriage is adapted to longitudinally move the filmstrip through the cassette passageway to present a selected row of microimage frames into the path of the projected light.

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First Claim