A viewing device for mounting in a wall or door frame to provide a view of the exterior of the building to an occupant of the building comprises a tubular housing and a pair of reflectors mounted by arms at one axial end of the housing so that they extend axially outward from the housing. The device further includes a transparent view housing which encloses the reflectors and prevents rearrangement of the reflectors while at the same time permitting a clear view of the area directly in front of the housing. The interior end of the tubular housing is enclosed by an eyepiece which can preferably be a magnifying type lens to increase the size of the images reflected from the reflectors and perceived through the transparent view housing.
A spyhole viewer for a door or wall, includes an objective system for producing a real, inverted image. The objective system is mounted in a tubular member fixedly installable in the door or wall. An erector is provided for inverting the inverted image of the objective system and is located behind at least one of the elements of the objective system. At least one reflector is provided for angularly deflecting the light beams from the objective system, and a housing is fixedly attachable to the tubular member for accommodating at least the erector and the reflector. A viewing lens is provided for magnifying the real image as inverted by the erector means. The viewing lens is adapted to swivel in a substantially vertical plane about an imaginary horizontal axis at a radius of swivel at least approximately equal to the length of the light path from the image-side focal plane of the objective system to the first principal plane of the viewing lens.
A spyhole viewer, mountable in a wall surface is disclosed and provides a wide angle view, while requiring a small diameter mounting hole. An objective lens system produces a real inverted image, a reflector angularly deflects light from the objective lens system, and an erector, located behind an element of objective lens system, erect the image. Further, a image surface upon which the image will appear, and a projection viewing lens are provided. The image optical axis is angularly deflected at least once between the objective and viewing lens systems.
