Virtual Reality (VR) immersive experiences feel to some like sci-fi made real, but the bulky, unwieldy norm for VR headsets are often too much to handle.
This is why researchers from Facebook Reality Labs recently proposed a new VR headset design — replacing refractive lenses with holographic optics and optical folding based on polarization, according to a post on Facebook Research.
Facebook researchers propose new VR headset design
In a new research paper from Facebook Reality Labs' Junren Wang and Andrew Maimone — titled "Holographic Optics for Thin and Lightweight Virtual Reality" — proposes a VR headset design that replaces the typical refractive lens with polarization-based optical folding and new holographic optics.
"We present a class of display designs combing holographic optics, directional backlighting, laser illumination, and polarization-based optical folding to achieve thin, lightweight, and high performance near-eye displays for virtual reality," reads the abstract of the paper.
Polarization-based optical folding and holographic optics "help keep the optics as thin as possible while making the most efficient use of space," read the post on Monday. "We anticipate that such lightweight and comfortable factors may enable extended VR sessions and new use cases, including productivity."
A turn from VR tradition
Typically, VR headsets have to be large to accommodate thick, curved lenses, which alter the angle of light from the display before we see an image with our eyes. This makes objects generated in VR look farther away than they really are.
Facebook's proof-of-concept headset replaces the old design with holographic optics — which seem like transparent stickers, but actually, bend light in the same way lenses do. According to Facebook Research, it's akin to the holographic image on a credit card, but instead of a 3D scene, it creates a lens. "The result is a dramatic reduction in thickness and weight," said the Facebook Research post.
Slim VR headset design comes with 'pancake' folding
However, it takes more than holographic optics to create a slim design. VR headsets also usually need significant distance between the lens and the display, so the image can come into focus. To reduce this gap without losing focus, Facebook's researchers used polarization-based optical folding — also called "pancake" folding, reports Mashable.
Pancake folding bounces light to and fro inside a lens several times before it reaches our eyes, which increases the distance light must travel while keeping the physical distance down to a minimum. Since Facebook's prototype is moving away from bulky lenses, the holographic optics create pancake folding, setting a new standard in VR headsets.
"Our proposed approach is to design a pancake optic where all the focusing power is performed by holographic optical elements rather than bulk optics," wrote Wang and Maimone in their paper. While aesthetically underwhelming, their cutting-edge research into the future of VR headsets will be presented during the virtual SIGGRAPH conference this August.