Abstract: A xenon arc lamp for a motion picture projector is cooled by providing the anode end of the lamp with a shroud that forms part of a support for that end of the lamp. Cooling air flows into the shroud along the support arm and enters the shroud through a slot in its side wall. The shroud provides an annular air space around the anode end of the lamp and has an annular air outlet through which the cooling air leaves as a “sheet” of laminar air flow which tends to adhere to the surface of the bulb, thereby providing precise cooling. In this way, arc instability is avoided or minimized, while lamp life is extended.

Abstract: A rolling loop motion picture projector is convertible for projecting images either from a 2-D film strip or from a 3-D film strip. The film is advanced through the same incremental amount irrespective of whether a 2-D film of a 3-D film is being projected. The projector has a single central aperture for projecting 2-D images and respective 3-D images on opposite sides of the central aperture. The images on the 3-D film strip are anamorphically compressed in the direction of film travel by a factor of two and the 3-D apertures are correspondingly sized. Projection lenses associated with the 3-D apertures decompress the images so that images of comparable size appear on the screen irrespective of whether a 2-D film or a 3-D film is being shown.

Abstract: A compact rolling loop motion picture projector has a rotor of significantly smaller diameter than a conventional such rotor. The radius of curvature of the rotor is selected to be significantly less than the radius of curvature of a film flattener element on which the film is located for projection, and the axis of rotation of the rotor is offset towards a film input sprocket of the projector so as to maintain a minimum film gap between the rotor and the field flattener upstream of the optical axis of the projector. The compact rotor is rotationally supported from above by a "spider" and a projection lamp is located below the rotor for compactness and efficiency of lamp operation.

Abstract: In an alternate eye 3-D motion picture projection apparatus of the rolling loop type, light projection is accomplished by the combination of focal plane shutters that are coupled to the rotor of the projector and a supplementary shutter arrranged to trim the projected light so that discrete "left eye" and "right eye" images are projected. Various embodiments are disclosed in which a rotary blade shutter is located at the stop of the projection lens. Where there are two projection lenses, a single blade or two counter-rotating blades trim the light projected through both lenses.

Abstract: A 3-D motion picture projector comprises two rolling loop film transport mechanisms arranged in vertically superposed relationship with the pricipal components of the two mechanisms in vertical alignment with one another. Each film transport mechanism includes a cam unit for decelerating the film as it approaches the aperture for projection. The two cam units are driven from a common vertical drive shaft by toothed belt drives. The lower cam unit is mounted on an arm so that it can be swung out to an inoperative position for maintenance and service. The belt drives maintain the drive coupling at this time and automatically restore proper cam timing when the cam unit is returned to its operative position.