The LEEP Viewer
Features and Specifications
The System 2002 viewer model LV2002 comprises a table top three-legged base with three diffusers, two viewing heads and a three-way 120v incandescent lamp. Two persons can use it simultaneously (to view different scenes) and it doubles as a Hi-Tech table lamp. A third viewing head is readily mounted, though for three-person viewing, a smallish table — a planter table or a chess table — would probably be called for. The viewing heads, with or without diffusers, can be removed for use with other light sources. The design is intended to encourage leaving some of the latest and best of your efforts on display (use dupes, please) and to permit a comfortable social interaction when viewing - like that of sharing prints, rather than that of imposing slides.
The viewing head incorporates two three-element magnifiers of 6 to 7 power (39 mm focal length) at a fixed interaxis spacing of 64 mm, and a lever-adjusted focussing stage giving simultaneous focus adjustment for both eyes. Tilting the stage will produce a different focus eye-to-eye of 2 or 3 diopters, and the tilt may be fixed. The mounted LEEP slides drop easily into place and are as easily removed. The use of eyeglasses is discouraged, as it limits the field of view, which is 90 to 100 degrees if the eyes are brought close to the eyelens, and up to 140 degrees if the head is moved laterally to peer to the left and right. A monograph proving that interocular adjustment is not needed will be sent to those requesting it.
The eye lens is 60 mm in diameter except that portions are cut away to make room for the bridge of the nose and brow ridge. Optically the magnifier resembles a very large Ramsden with an added field correcting element. The combination of high power and wide angle is possible because there is no correction of distortion lateral color, both of which are incorporated in a compensating sense in the images of the LEEP stereograph. This "neutralizing" is the heart of the invention.
Left: The LEEP Viewer at the Bostom Museum of Science.
From November 1983 through January 1984, as part of a comprehensive 3-D exhibit, the viewer with three heads and fixed focus, was on display at the Boston Museum of Science. Located in the "Hi Tech" section of the exhibit, it easily held its own against 3-D television and video games.