special readout display Technology from 1969 projection and moving coil

[oz2cpu]

I had the idea i have seen and touched it all :-)
how wrong was I
just found this frequency counter at a local fleamarked,
it looked like side lit displays, those are also cool vintage and all that,
but it turned out to be even more nice and special,
here is a little video if you like to see all the details

https://youtu.be/6h7kBTZuICg

[Gyro]

Beautiful technology. Member Mike'sElectricStuff did a writeup on the 3336 which used the same technology...

https://www.electricstuff.co.uk/venner.html


Venner invented the mechanical timeswitch that went on to be used in all UK street lights until the advent of daylight sensors.

[oz2cpu]

thanks a lot Chris, i have added that link to the video description
at the bottom of that page he show exactly my model,
but I think that picture could have been from the net ?
since mike also make youtube videos and i was not able to find anything

[Doctorandus_P]

I once demolished a few similar displays.
They had 12 light bulbs (numbers, dot and some extra, maybe a plus sign or slash) in a 3 by 4 array and each light bulb had it's own lens.

[oz2cpu]

so what you talk about is a side lit ?

[TimFox]

Some of those I remember from ca. 1970 had individual "slides" with numbers or symbols between an incandescent bulb (one per slide) and its focusing lens to image the slide on a ground glass.
This could be very flexible, with any reasonable number of slides and arbitrary symbols as required.
I don't remember the name of the US manufacturer of these displays.

[oz2cpu]

what i think you talk about Tim
is the side lit, or edge lit, as we use to call them,
it consist of thin plastic or acrylic slides with engraved numbers, and one individual bulb lit each slide where the number then light up
they are also super cool and vintage, also from 1960-70
there was a nice overlap with the nixie area,
then the nixies won it all..

[themadhippy]

One of these by any chance? skip to 10:40 for the relevant bit

[Neomys Sapiens]

Some of those I remember from ca. 1970 had individual "slides" with numbers or symbols between an incandescent bulb (one per slide) and its focusing lens to image the slide on a ground glass.
This could be very flexible, with any reasonable number of slides and arbitrary symbols as required.
I don't remember the name of the US manufacturer of these displays.

Did you think of one out of those:
https://www.industrialalchemy.org/tubepage.php?item=10&user=0

[TimFox]

what i think you talk about Tim
is the side lit, or edge lit, as we use to call them,
it consist of thin plastic or acrylic slides with engraved numbers, and one individual bulb lit each slide where the number then light up
they are also super cool and vintage, also from 1960-70
there was a nice overlap with the nixie area,
then the nixies won it all..

No, the ones I mentioned were rather deep modules, with a miniature projector for each displayed symbol.
I think they were like the "IEE 10000-1819-B Projection Display" discussed in Neomys Sapiens' post above.
The "slide" for each symbol was maybe 5 mm diameter, for a 25 mm ground glass.
I have also seen the edge lit ones you mentioned:  they were not so deep from the front panel.

[oz2cpu]

exactly tim, now i know what you think about,
the video themadhippy posted at 1040 show exactly what you talk about,
this basis idea behind that design i like, since there are no moving parts,
how ever the adjustments of all projected pictures, so they align correctly to the screen
must be a nightmare, the video also clearly show how bad they can be to hit the correct spot :-)
I dont think i got any of this model stocked, but i do remember taking some apart as a kid 40 some years ago

[Doctorandus_P]

Indeed. Not side lit, but the same internals as themadhippy links to in his posted video.

Even though the light bulbs are obviously not all in the center, you can project all digits in the center by using lens shift in photography, or mechanical keystone correction in a beamer.

[TimFox]

The advantage of the back projection onto a ground glass is that the large symbols are all in the same plane.
I found it amusing to watch nixies count, since the cathodes were arranged to minimize obstruction of each other, and the incrementing numbers went back and forth like a trombonist.