Card – picture – or sign exhibiting – Calendars
Patent
1974-07-12
1977-01-25
Mancene, Louis G.
Card, picture, or sign exhibiting
Calendars
40132D, 240 2AT, G09F 1310
Patent
active
040043606
ABSTRACT:
Apparatus having a translucent viewing screen forming a wall of a cabinet and provided with regularly spaced holes extending into the interior of the cabinet. A vacuum pump reduces pressure within the cabinet interior and the resulting pressure differential created at the front face of the screen serves to hold photographic transparencies in position for viewing. The cabinet has lamps arranged to backlight the viewing screen and illuminate the transparencies. An opaque grid is provided between the viewing screen and the lamp and this grid has a chamber in communication with each hole. Each chamber is fitted with a flap-like shutter for controlling the passage of light through the chamber to the screen. The flow of air through those holes which are not covered by the transparency is utilized to close the shutters of the associated chambers thereby effectively masking the areas of the screen surrounding the transparencies.
REFERENCES:
patent: 2590044 (1952-03-01), Schaller
patent: 3391480 (1968-07-01), O'Keefe
patent: 3616554 (1971-11-01), Singer et al.
patent: 3892080 (1975-07-01), Koch
Mancene Louis G.
Pitrelli John F.
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