The Original Seven (Eight?) Segment Display

The seven-segment LED display is ubiquitous. But how old do you think the fundamental idea behind it is? You nixie tube fans will be thinking of the vacuum-tube era, but a reader sent us this patent filed in 1908 where [Frank W. Wood] builds a numeric display with plain-vanilla light bulbs, slots cut in wood, and lots of wires.

The OCR on the patent is poorly done — you’re going to want to download the PDF and read it locally. But as it states in the patent, “Referring again to Fig. 1, the novel arrangement of the lamp compartments will be readily understood.”

Technically it’s not a seven-segment display at all. [F.W. Wood] designed these really nice-looking “4”s with the diagonal heads, and so he needed eight segments per digit. But the basic idea shines through, if you pardon the pun.

The other figures demonstrate the machine that’s used to send the signals to light up the lights. It’s a rotating drum with the right contacts on the bottom side to make connections and turn on the right lights at the other end. Low tech, but it’s what was available at the time.

We’re stoked that we’re not responsible for wiring this thing up, and we’re a bit awed by how old the spirit behind one of our most ubiquitous technologies is.

Thanks to [mario59] for the nostalgic tip!

36 thoughts on “The Original Seven (Eight?) Segment Display

    1. Oh, it has been a striking discovery also for me!
      Facit did once… 6 segments displays!!! Even thou the appearance was not all that satisfying for number “1” they did a segment only for it…, here they are:
      Personally I think that computers have not *really* pushed the mankind’s intelligence really forward… I think it only relieved human beings from cumbersome tasks!

      1. The way the Facit 1111, Sharp EL-8 and Addo-X were built brings the possibility of designing entirely new plug in boards to use the original keypad and display.

        Someone should take the design of the digits on those calculators and base a complete font on them.

  1. Very cool, thanks for posting this!

    The ‘referenced by’ links lead to a deep rabbit hole of all kinds of segmented display technology throughout the 20th century. I haven’t found the first patent citing LEDs instead of incandescent bulbs; maybe that change wasn’t sufficiently novel for a patent? Anybody else want to try?

    1. it’s not novel at all. I found a (dead) alarm clock that used the mechanical spool segment encoder that used discrete neon bulbs and had a mechanical clock with the ‘hands’ of the clock using this type of contact spool to run the clock segments

  2. I want to know what RANGE, DEFLECTION, ORDER, COMMENCE and CEASE on the display were for. Was this intended to be a display for an artillery aiming system? Perhaps for a commander to send directions that unlike voice transmissions by radio or wire wouldn’t be heard wrong or blotted out by battlefield noise?

    1. Battlefield noise?
      Screw that, the muzzle blast on a big ship gun would be enough on it’s own to need a system like this ;-)
      Also, it gives both ends (the team doing the calculations and the team operating the gun itself) a means to double/triple/infinitely check what they sent/received without bothering the other side…

    2. Yes, this device was for warship management… as most patents of this inventor was…
      see here:
      there’s a list of patents pending to him,even a… MOSQUITO SWAT (killing flies)!!!
      believe it or not this humble tool has an inventor behind it wit a Patent Pending!!!

      1. I thought “I’ll bet was the first (-ish) person to use mesh so they fly doesn’t get blown out of the way’.

        And yep, that’s it. I wonder when fine wire mesh was invented or made cheaply.

        And there’s no patent pending, he got it granted. Wonder if he made any money out of it.

  3. I’ve always wanted to respin the 7447 chip to get rid of the extra segment on the 7, it looks really ugly.

    Instead of the diagonal for the 4 I’d like to see a display with a full diagonal slash so it makes a really good looking 7 and you can also slash the 0 if you want.

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