Abstract: A stereoscopic viewing device of the lorgnette type. The device may be fitted with accessories such as a hingedly mounted bridge member and adjustably mounted bow members. When positioned normal to the plane of the base member, the bridge member spaces the eyes of the viewer a predetermined distance from the base member and allows the viewer to hold the device with a minimum amount of instability. Bow members of the type used in spectacles, but having adjustable positions, are provided as an alternative to the standard handle member. An improved septum is provided by positioning base out prism lenses of the type formed from simple whole lenses such that the excess lensed aperture areas are eliminated and the need to frost or otherwise render opaque the nasal edges of the lenses is obviated.

Abstract: A stereoscopic viewer comprises a housing having an advancing plate for supporting and advancing a disc-shaped carrying card for stereo images which are viewed through a pair of eyepieces in the housing. A trigger oscillates the plate to incrementally rotate the card and position sequential pairs of images in the viewing axis of the eyepieces. The trigger includes a depressible actuator vertically projecting through a top surface of the viewer, as it is held for viewing. The trigger comprises a cylindrical actuator portion projecting through the top surface of the housing, and a leg depending from the actuator portion which engages the advancing plate to oscillate it as the trigger is depressed. As the plate oscillates in a forward direction, a flat front face of a pawl on the plate engages a radial slot on the disc to rotate it. The pawl is slightly inclined in the direction of advance of the card to help hold the card flat against the plate during incremental advancement.

Abstract: A variable focal length lens system comprising a first lens unit having positive refractive power, a second lens unit comprising a negative lens, and a third lens unit comprising a positive lens and arranged that the focal length of the lens system as a whole is varied from the short focal length to the long focal length by moving the first and second lens units toward the object side along the optical axis, the variable focal length lens system being arranged very compactly, i.e., arranged that the overall length of the lens system is very short and the outer diameter thereof is very small.