Long ago I worked with a counter or frequency generator with this type of display and it was called a "sphericular optic display" and a manufacturer was Burroughs. That term might help people search for them. (I also used a digital voltmeter with the type of display with the little flaps with numbers on them like many "digital" clocks of long ago. I think it was a Dana voltmeter. Of course, the wheels with the flaps had to spin around with every reading. Pretty entertaining.)
Eons ago I had a device that used numeric projection displays. They were a PIA as the bulbs would burn out periodically, especially those lamps illuminating the most popular numbers such as zeros. :-) Good riddence.
I have a large number of the incandescent/projector type displays and would happily sell them cheaply. There are two catches. One is that they don't include the light bulbs. The other, perhaps bigger, catch is that the film with the legend is a customized display that does not included a full set of numbers, at least not on any that I have checked. I have several variations with various legends, but as I recall most are specific phrases. The film is easily removed and it might be possible to print a new legend film using clear (overhead projector) film in a laser printer without having to go through a photographic process.
The projector modules themselves are "new old stock" government surplus. I believe they were used on C130s. They are definitely an aircraft part. I would love to repurpose them. I've thought about doing something like this, but never came up with the time and ambition to actually do it.
Note that there's no reason the image can't be in color, if one had a way to print it. I suspect 35mm slide film would be the right size if one wanted to try doing it photographically. If anyone's interested in giving it a try, contact me at davids@SlateCreekEngineering.com.
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