Importance

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Abstract

An improved filmstrip-carrying cassette, the filmstrip carrying thereon microimages arranged in rows and columns, and a viewer for illuminating, projecting, enlarging and reading on a display screen a selected one of the microimages is provided, using a pair of transparent plates to engage a selected portion of the filmstrip on opposite sides to hold same in a precise focal plane for properly illuminating and projecting the selected microimage. The filmstrip has great width to accommodate multiple rows of microimages, and motor means operate to transport the filmstrip selectively in opposite directions to quickly locate the column in which the desired microimage is located. The cassette is carried by a viewer-mounted carriage that is manually reciprocable along a track, so as to traverse the column in seeking the desired microimage. The transparent plates are separated simultaneously with the energizing of the motor means to permit unfettered movement of the filmstrip. In one form of construction, the transparent plates are carried by the cassette. In a preferred form, the cassette carries one transparent plate, and the other plate is carried by the viewer's carriage; the motor means provides selectively fast or slow transport, and the transparent plates are caused to separate only during fast transport, to provide visual coordination for locating the selected microimage with the slow transport of the filmstrip. A modular construction for the light projecting portion of the viewer provides for simplicity of adjustment and servicing.

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First Claim