A projector comprising a film supply support and a film receiving support for film supply means and film receiving means, respectively, means for advancing film from said film supply means to said film receiving means, a light source providing light through said film, an image surface, an optical system for projecting an image from the film to said image surface, said optical system comprising a lens of lower magnification and a lens of high magnification positioned transversely one to the other with respect to a common field of view, shifting means for interchangeably positioning said lenses behind said film, said lens of higher magnification projecting an image reduced in area compared to that projected by said lens of lower magnification to project select areas of the image projected by said lens of lower magnification.
A slide projector located within a rear-screen projector has means therein for projecting images, contained on slides, onto a self-contained projection screen. Two lenses having different focal lengths are mounted within the projector housing and may alternatively be brought into the optical path for projecting slides, having different size formats, such that the projected image fills the projection screen.
Apparatus and a method for handling and reading any one of a number of film strips, each having a number of segments with each segment containing a plurality of information-containing, high-reduction image frames. The film strips are housed in a cassette which is movable with respect to a fixed reference to align a desired film strip with a reading station disposed across the optical path of an optical system. A film strip is moved out of the cassette by a force applied to one of its side edges. Control information carried by each film strip is sensed as the film strip moves out of the cassette and the sensed information is used to control the distance through which the film strip moves so that a particular segment thereof will stop at the reading station. The optical system is moved relative to the reading system so that the optical path of the optical system is selectively alignable with a particular image frame of the film strip removed from the cassette.
A microfiche reader provided with a pair of lenses of different powers selectively and simultaneously shiftable into and out of alignment with the fiche projecting light beam. The lens in use rests by gravity on an X-Y fiche transport supported on a turn table. The lens shifting mechanism includes a device holding the lens in use firmly stationary despite both rotary and linear movement of the fiche transport. Simple linear movement of the lens shifting mechanism functions to elevate one lens while lowering the other gradually into contact with the fiche transport. The lens support assembly includes components for automatically adjusting the intensity of the light beam to provide the same lighting intensity on the image viewing surface for each lens. The lens support assembly is readily removable as a unit for servicing and the substitution of another assembly while the first is undergoing repair.
There is disclosed an optical control mechanism for use in a projection device such as a microfilm reader. The optical control mechanism effects selective positioning of one of two lens assemblies on the optical axis of the projection apparatus and locks the selected lens assembly in position. A pair of projection lenses of different magnification are mounted on a bracket which is keyed to a rotatably mounted shaft. The shaft is rotatable about an axis substantially parallel to a portion of the optical axis of the projection apparatus so that one of the projection lenses may be selectively aligned with the optical axis of the projection apparatus by rotation of the shaft. An optical control mechanism includes a control member such as a knob which is mounted for rotation between a first control position and a second control position. The control member is operatively coupled to the shaft by means of a bell-crank connected to the control member, a spherical member secured to the free end of the bell crank and a U-shaped spring member operatively connected to the shaft and projecting radially therefrom. The spherical member is located between the upstanding arms of the U-shaped member and is in substantial operative engagement therewith.
A microfiche reader incorporating an indexed magazine from which fiche cards are selectively extracted, positioned horizontally for viewing and returned to the magazine, all with a single lever. A second lever moves the projection lens and lamp assembly vertically relative to the fiche card, a position indicating grid showing the frame of the fiche card in projection position. The image is projected on a large viewing screen, at the side of which is a small screen showing the identification of the fiche card being viewed. An index frame carrying the contents of the specific magazine, can be moved into projection position to facilitate selection of individual cards and frames.
