It's "augmented reality", so multiple people can walk around and see the display from all angles at the same time. So it's beyond stereoscopic, but it's not a traditional hologram. (It's much better than the Tupac "hologram" which was a single 2D image!)
It works by stereoscopy. There maybe something "holographic" in the math used to compute what to show each eye, but there is no projection of light into space to form holographic images that people can walk around.
Nor is there with holograms. Holography requires creation of light fields from a flat surface - each point on the surface reflects a different amount of light depending on what angle it is viewed from, exactly mimicking the way light would pass through that plane if an object were there. No 'projection of light into space' is involved.
Since images are formed on your retina by focusing real lightfields, a true holographic display which produced a complete lightfield would be much more realistic and comfortable to view than a flat stereoscopic image is.
I don't know enough about holography to agree or disagree, I was under the impression that the "lightfield" has a 3D structure that e.g. the light coming from a movie screen doesn't.
In any event I don't think that the "holographic" goggles are actually projecting a complete lightfield. I'm pretty sure they just shine two more-or-less normal images into your eyes although the math to compute those images might, uh, be holographic.
You can capture a lightfield using a 2d sensor https://www.lytro.com/ It's like the way your eye can re-focus on different distances without moving. That's something you can't do with MS's new tech - everything in the image will be in focus at the same distance, even if your eyes are getting different images.
I doubt it actually has a holographic display; I assume that processing power of those glasses isn't enough and current display don't have high enough resolution yet. But then again the following description could be a holographic display (or it could be a description of antireflective coating -- those dumbed down explanations are sometimes worse than useless)
> To create Project HoloLens’ images, light particles bounce around millions of times in the so-called light engine of the device. Then the photons enter the goggles’ two lenses, where they ricochet between layers of blue, green and red glass before they reach the back of your eye. “When you get the light to be at the exact angle,” Kipman tells me, “that’s where all the magic comes in.”
Yes, that description certainly -sounds- like they're doing something more than just suspending two stereographic LCD displays in front of your face. Talk of angles suggests they may be doing something to stimulate the correct lightfield passing through the pupil of your eye... but really, need more technical reviews to know more.
