Are Facebook's Holographic VR Glasses Viable? One Expert's Deep Dive

UploadVR has an interesting story on a new prototype created by Facebook’s VR research division which replaces the traditional, totally bulky virtual reality headset with something closer to the sunglasses form factor we've been wanting since Snowcrash:

Facebook Reality Labs’ new approach is a thin film where focusing is done by holographic optics instead of by the bulk of the lens. "Hologram" in this context just means a physical “recording” of how light interacts with an object- in this case a lens rather than a scene.

Facebook claims the research may be able “to deliver a field of view comparable to today’s VR headsets using only a thin film for a thickness of less than 9 mm.” The total weight of the display module is claimed as just 18 grams.

But is this approach viable? I put that question to a colleague who happens to be one of the world's top experts in AR/VR technology (and so prefers to remain anonymous). They read Facebook's research paper associated with this prototype, and came back with this assessment: 

 "I think the tech is cool and the research is good for longterm innovation but is likely years away from a product. I think the Panasonic and other pancake optics is a bit closer."

What's holding Facebook's approach back? 

Here's the deep dive from my expert, citing the research paper:

"Here are a few areas that will need to be improved before this is productized. Eye box and eye relief is really small. Like trying to look down the cap of a sharpie pen with a precise distance from your eyes: 

8mm eye boxes of our prototype displays were suitable as monocular demonstrators, we require a larger eye box of 10–12mm to achieve a practical stereo headset.

"Their target of 10-12mm in the future is smaller than systems like Magic Leap, which is already difficult to line up to the users' eye for a good experience. The image disappears if your eye falls out of the eye box when looking around or if the glasses tip on your head. The image isn't uniform across the eye box. They describe it as a radial sync pattern. I suspect this will change depending on your eye position."

More challenges, citing the research paper.

"They use lasers which have speckle. They've been able to reduce this by using external despeckle units fed to the glasses by fiber optics:

Speckle was suppressed well by the despeckler unit. Only a small amount of noise remained, and was most salient during dynamic content. Without the de-speckler unit, the image quality was unacceptably noisy.

"They have ghost images which need work:

Finally, note that is there a small blue ghost image of the grid in the center of the field of view due to leakage through the polarization optics. We believe the ghost could be suppressed by ensuring that all surfaces are anti-reflection coated.

"It's difficult to make holograms that work with red, green and blue light at the same time. They say they need to work on this:

Fig. 13. Benchtop prototype calibration image. Photograph of benchtop prototype displaying a grid of white lines, which reveals color misalignment and non-uniformity issues and a ghost image at the center of the FOV.

My expert's overall assessment of Facebook's plans for this: Even if they reach their stated technical targets, the device might still not be ready for the mass consumer market.

 

"I think the if they get to their goal of 10-12mm eyebox the user will still struggle. They may need to add adjustment screws or have them fitted to the user. Just the distance between eyes of an average person can vary that much. 12mm is about the size of a dime. The size of the eyebox they're shooting for reminds me of the Avegant Glyph that needed constant adjustment to use."

 

And using this HMD might be a non-starter for people who need to wear corrective vision glasses:

 

"Looks like they're working about 14mm away from the users eye which is very close. Not much room for glasses... Looks like one of their prototypes were at 14mm, 17mm, and 21mm away, which is very close to the users' eyes. I don't see them calling out the working range, but we might infer it's 5-6mm."

 

In other words, when using it: "Don't let the glasses slip down your nose or you'll lose the image."

 

So don't expect to be wearing holographic sunglasses any time soon, sounds like.

 

All those technical hurdles aside, I think the cultural challenge will also be hard to overcome: Wearing a bulky HMD quickly and clearly communicates to others, "I'm busy in VR, leave me alone for awhile." Whereas an HMD that looks like sunglasses will confuse our existing social cues:

 

If someone is wearing dark glasses indoors, are they in VR, or are they blind? Or are they sad? Or maybe just pretentious?

Comments

[jetbox]

They look promising.

[camilia fid3lis nee Patchouli Woollahra]

*sits down on a plywood prim with a blocky cigarbox banjo*

I wear my sunglasses at night,
so I can, so I can
bed Taylor Swift
inside the Oculus Rift...

*blinks blankly* *coughs*
Boy, mixing Father Misty and Corey Hart is NOT doing it for me.