Why Augmented Reality Is So Hard (The Information)
Since the article is behind a paywall and not many have access to it, I'd like to share a few things that struck me most:
AR is constrained by laws of physics at the moment, and not by Moore's law. It's not that the computing chips need to become smaller or faster, it's the lenses and mini-projectors that need to shrink to fit into a set of normal-looking glasses. And there's no Moore's law of optics.
Having said that, the computing power is also a limiting factor, but not as much. For a point of reference: when Hololens was first announced in 2015, they had to put the prototype in a refrigerator before use since it used to become too hot.
Hololens uses diffractive optics which can be shrunk down, but:
is fragile since if one of a million of tiny structures in diffractive optical elements has a defect, the whole thing is useless;
different wavelengths may bleed into each other, resulting in a blurry image;
and it's expensive to manufacture.
Magic Leap has tried various approaches in the past, and the industry believes the limiting factor is not money, but lack of a breakthrough.