Abstract: A rear projection monitor having a housing with reduced depth is disclosed. Images produced by liquid crystal active matrices are illuminated by a light source. The images are enlarged and projected by a projection lens having a large rear focus. A mirror reflects the projected images onto a viewing screen. The mirror is positioned between 36.degree. and 45.degree. in relation to the viewing screen. The back of the housing is adjacent to and slopes at the same angle as the mirror. The depth of the projection monitor is between 33% to 41% of the diameter of the viewing screen.

Abstract: A lens assembly, including at least one plastic lens element axially aligned with another lens element of glass or plastic and adhesively bonded together by a polysiloxane room temperature curable cement, the bond between the plastic element and the cement being improved by a primer layer comprising an aliphatic polyurethane.

Abstract: An adapter is provided by which an image formed by the eyepiece of an optical viewing device such as an endoscope can be simultaneously viewed and photographed with a motion picture camera of the type having a reflex viewing system which has an entrance pupil that occupies only a portion of the camera objective taking lens system and which is offset with respect to the optical axis of the camera objective taking lens system. The adapter operates to align the center of the viewing device exit pupil at a predetermined point along a line connecting the centers of the camera objective lens system and viewing system entrance pupils to preclude vignetting of the camera viewing system entrance pupil.

Abstract: An accessory attachment for use with a camera of the type having a frontal generally parallelepiped housing for an objective lens, a shutter mechanism, and camera function-controlling devices such as photocells and shutter or control knobs or buttons. The attachment serves to mount accessories such as auxiliary portrait, wide-angle, or telephoto lenses, filter lenses for the camera's objective lens and photocell, auxiliary shutter or control knobs, and flash equipment, in aligned operative relation to the corresponding elements of the camera. The attachment comprises a housing mounting the accessories in a front portion, and a pair of wing portions extending rearwardly to embrace the side walls of the lens-shutter housing, and bearing a pair of opposed latch portions which releasably engage rear corner portions of the side walls. Locating flanges in the side walls of the lens-shutter housing align the attachment correctly with the camera.