The overall effect of this display system (called TransPlay) is that of a crazy bright animated laser picture hanging in midair. It’s great for store displays and whatnot, but Sun Innovations has a more useful implementation built into a car windshield that traces your route out like a GPS. A GPS with lasers, which automatically makes it the coolest GPS we’ve ever seen.
The secret is in the transparent plastic that’s used as a screen: it’s not entirely transparent. In fact, it’s not transparent at all at a couple very specific wavelengths, which are also the wavelengths pumped out by the laser projector aimed at it. These wavelengths are narrow enough that our eyes see right through them, but they’re still wide enough to be able to reflect several colors worth of narrow band laser light. Very cool!