Same here :). But original Optimus has a screen in each key. This technically similar to a later design https://www.artlebedev.com/optimus/popularis/. Which also had a single big LCD and transparent keys on top of it.
Elgato's Stream Deck is a more mainstream application of the same approach, with a single LCD under all of the keys.
The Stream Deck isn't doing anything particularly exotic with its key mechanism, though (from what I can tell, there's a frame between the LCD and buttons with the actual contacts on it; no Hall-effect sensors or anything like that).
The Stream Deck isn't doing anything particularly exotic with its key mechanism, though (from what I can tell, there's a frame between the LCD and buttons with the actual contacts on it; no Hall-effect sensors or anything like that).