Yeah, I'm curious too, not just in what it's for, but how you provide the power to that - assuming a ~3V forward voltage drop on the leds, you need ~500Amps to light that up.
Each of those squares was a ~2m x 2m array of individually addressable tricolour leds (they could play video on them). Individually addressable means the can't run any of them in series - the whole panel needs to run at the forward voltage of the blue leds, or ~3V. I'm assuming they're built out of the individually addressable led strip like I can buy at Adafruit, so 32 tricolour leds per meter, for a total of 64 x 64 leds each with 3 emitters =~ 12,000, which at 20mA for each emitter requires ~250A to drive it all to full brightness white (which'd "only" be ~750W). They had 12 of those panels on stage. How the hell do you provide 3000Amps at ~3V? I know that's only ~9kW, which isn't a lot of power (in the context of a concert lighting rig), but doing it at 3V and 3000A is quite a different thing to 110V or 220V lamps drawing "only" 80A (or 40A @ 220V) in total. A 3000A power supply must have some impressive amounts of copper leading out of it. Even if it's 12 individual 250A power supplies, that presumably implies thumb-sized or thicker copper wire to pass those currents (and even thicker if the cable runs are any sort of length, the I squared term in I^2 x R power losses mean R needs to be _very_ low at 250A to stop things catching fire…)
A digitally controlled light source for a, well, shall we say, special application.
The light source was about 24 x 16 inches with LED's packed as tight as you can imagine. For best thermal transfer and uniformity the assemblies were bonded to a 0.5 inch thick aluminum base-plate in a vacuum fixture.
To answer the other question, power was provided by a set of 48V 500W AC to DC power supplies feeding purpose-built current and voltage control boards.
It produced an output luminance of about 60,000 cd/m2 (sixty thousand candelas per square meter). In other words, it was actually dangerous to look at it directly, all measurements had to be taken through stacks of attenuating filters. Fun project but about as dangerous as working with lasers.
