How two Valve engineers walked away with the company's augmented reality glasses

This is the weirdest approach to video glasses I've ever seen - really clever but strange. (that's not necessarily a bad thing)

They put 2 projectors on the glasses, pointing out. These are obviously extremely weak because they're so small, but the trick is shining the light at a retro-reflector [1] which bounces almost all the light directly back where it came from.

So even though the projectors are so dim you'd barely be able to see the image normally, it's apparently bright enough since a significant fraction of the light energy is bounced directly back to your eye. I assume they're using 2 projectors because the angle of return is so focused that it wouldn't be sufficient to use one projector between the eyes.

My only confusion is I don't get what this has to do with augmented reality. All that cleverness just emulates what a normal monitor can do - display an image to a person. The head tracking stuff is a completely independent system of camera and IR light, just like a wiimote sensor. Anyone have thoughts on why they need this new imaging system?

[1] http://en.wikipedia.org/wiki/Retroreflector

My respect for Gabe Newell just went up:

Says Ellsworth: "Gabe was completely behind it... I talked to Gabe, and he talked to the lawyers, and he's like, 'It's theirs, make it happen,' because he could see we were passionate about it."

It's appalling how the Verge commenters see this purely as a gaming device and not as a serious/less creepy competition for Google glass once the FPGAs are replaced by ASICs.

Based on the looks of that thing, maybe that's why they got canned?