Dipping into virtual reality can feel like a science fiction fantasy come true, but bulky and cumbersome virtual reality headsets almost make it more troublesome than it’s worth. There have been several attempts to slim down VR headsets such as Dlodlo’s lightweight V One headsets and Panasonic prototype glasses shown at CES 2020. Now Facebook has revealed its own prototype glasses-shaped headset with an 8-screen, 9mm thick, approximately the same thickness as a smartphone
In a new research paper titled “Holographic Optics for Thin and Light Virtual Reality,” Facebook Reality Labs researchers Andrew Maimone and Junren Wang have proposed a VR headset design that replaces the refractive lens with holographic optics and optical folding based on Polarization. This allows the headphones to be much lighter and more compact, like an oddly thick pair of retro sunglasses.
“These two methods help keep the optics as thin as possible while making the most efficient use of space,” Facebook Research said in a blog post on Monday. “We anticipate that these lightweight and comfortable form factors can enable extended virtual reality sessions and new use cases, including productivity.”
VR headsets should generally be large to accommodate a thick, curved lens, which changes the light angle of the screen before it reaches your eyes. This is what makes virtual reality objects appear farther than they really are.
Facebook’s new proof-of-concept headset replaces this lens with holographic optics, which looks like clear stickers but bends light in the same way as a lens. Facebook Research compares it to the holographic image on your credit card, only instead of creating a 3D scene, it creates a lens. “The result is a dramatic reduction in thickness and weight,” wrote Facebook Research.
However, holographic optics alone is not enough to give Facebook headsets their slim design. VR headsets also often require a significant distance between the screen and the lens in order for the image to focus correctly. To narrow the gap needed, Facebook researchers used polarization-based optical folding, also known as “pancake” folding.
Simply put, pancake folding bounces light back and forth within a lens several times before it reaches the eye, increasing the distance light travels and keeping the actual physical distance small. Because the Facebook prototype avoids bulky lenses, its holographic optics cause the pancake to bend.
“Our proposed approach is to design a pancake optics where all the focusing power is realized using holographic optics rather than bulk optics,” Maimone and Wang wrote in their article. Their research will be presented at the SIGGRAPH virtual conference in August.
Although less cumbersome than other virtual reality headsets, the Facebook prototype will probably still annoy people who already wear glasses.
As exciting as it is, Maimone and Wang point out that they are only in the investigation phase. Facebook’s VR headset still has a lot of issues to solve, and it’s years away from reaching consumers.
For example, the headset currently uses external components like light sources and display drivers that would have to be integrated into its small frame. The prototype was also designed to show only Matrix– as shades of green for simplicity, although Facebook researchers hope to eventually use laser light sources for an even wider color gamut than standard Red Green Blue displays.
Still, Facebook’s relatively slim virtual reality headset prototype is an exciting step toward more practical virtual reality and potentially more widespread adoption of the technology.
“Lightweight, high-resolution, sunglasses-like virtual reality displays may be the key to enabling the next generation of demanding virtual reality applications that can be leveraged anywhere and for long periods of time,” Maimone wrote. and Wang.
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