Burroughs SD-11-B-1000-635  
Written by Accutron on 2017-03-17  

Although it resembles a typical projection display, the Burroughs SD-11-B-1000-635 Message Display Unit is actually a sphericular optic display. At the rear of the display is an array of 11 lamps, one for each digit plus a decimal point. At the front of the display is a screen assembly constructed from three layers. The rear layer is a transparent plastic sphericular lens plate covered in a grid of plano-convex lenses. Each lens measures 0.025" square, with a focal length of 0.078". In front of the sphericular lens plate is a message screen, positioned at the focal plane of the lens plate. The message screen is constructed from a plastic film with an array of printed dots which selectively block the lamps' illumination to generate each digit's respective dot pattern. The final layer of the screen assembly is a diffusing layer which increases the display's viewing angle.

Burroughs manufactured at least two variants of the SD-11. The SD-11-B-1000-635 pictured here has black digits on an illuminated background, while the SD-11-W-1000-635 has illuminated digits on a black background.

Special thanks to Victor Rizzardi for donating these rare displays.

Burroughs SD11-B-1000-635 sphericular optic display.

SD11-B-1000-635, internal construction.

This article is part of the [Incandescent Displays] exhibit.

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