[Fran Blanche] tears down this fascinating display in a video teardown, embedded below.
These displays can support up to 64 characters of the buyer’s choosing which is controlled by 6 bits, surprisingly only requiring 128 mW per bit to control; pretty power-light for its day and age. Aside from alphanumeric combinations the display also supported “color plates” which we found quite fascinating. The fully decked model would only cost you $1,206 US dollars per unit in today’s money or five rolls of toilet paper at latest street price. And that’s just one digit.
If you dig through the documents linked here, and watch her video you can get an idea of how this display works. There are six solenoids attached to rods at the rear of the device. A lamp shines through a lens onto the back of a plate assembly. Each plate is a strategically perforated grid. When the solenoids activate the selected plates tilt interfering with a stationary grid. This causes the light to be blocked in some regions only.
It seems clear why this never took off. Aligning these seems like a production nightmare compared to things like flip displays and Nixie tubes. Still, the characters have quite a lot of charm to them. We wouldn’t mind seeing a 3D printable/laser cut version of this display type. Get working!