Meta is constructing a prototype headset referred to as ‘Mirror Lake’ to show out “practically all the superior visible applied sciences that we’ve been incubating over the previous seven years” in a compact kind issue.

Mirror Lake hasn’t but been constructed right into a purposeful machine – it’s nonetheless only a idea being actively labored on. Chief Scientist of Meta’s Actuality Labs division Michael Abrash mentioned Mirror Lake “exhibits what a whole subsequent gen show system may appear to be”. Again in 2019 Abrash introduced Fb was constructing a “true subsequent era idea prototype” VR headset, nevertheless it’s unclear what occurred to that concept.

The idea is designed to attain a “ski goggles like kind issue” with what Meta calls Holocake lenses, whereas incorporating superior eye monitoring, variable focus, reverse passthrough, and assist for prescription lens attachments “to eradicate the necessity for eyeglasses”.

To be clear, Mirror Lake will not be a product. Meta CEO Mark Zuckerberg advised the know-how it proves out may very well be seen in merchandise “within the second half of the last decade”.

Varifocal

All present VR headsets, exterior of lab prototypes, have mounted focus lenses. Every eye will get a separate picture, however the photographs are centered at a set distance. Your eyes will level (converge or diverge) in direction of the digital object you’re taking a look at, however can’t correctly focus (accommodate) to this distance. That is referred to as the vergence-accommodation battle. It causes eye pressure and might make digital objects look blurry shut up.

At its F8 convention in 2018 Fb confirmed off a prototype headset referred to as Half Dome, which included eye monitoring to mechanically transfer the shows ahead or again to regulate focus. Half Dome solved the vergence-accommodation battle however the mechanical strategy would current critical reliability issues in the actual world, making it unsuitable to be shipped in merchandise.

At Oculus Join 6 in 2019 Fb described Half Dome 2 and Half Dome 3. Half Dome 2 used extra dependable actuators and a extra compact (however decrease subject of view) design. Half Dome 3 nevertheless took a very new strategy with no shifting components. As an alternative of shifting the show, Half Dome 3 makes use of a stack of liquid crystal lens layers. Making use of a voltage to every lens layer adjustments its focal size, so every distinctive mixture of on and off ends in a distinct focus distance. With 6 layers, there are 64 completely different potential focus distances.

Whereas Half Dome 3 is extra compact than its predecessors, it’s nonetheless a lot bigger than the “ski goggles like” kind issue Meta desires to attain. Mirror Lake will use the identical strategy as Half Dome 3 however in a considerably smaller kind issue, achieved via the usage of “Holocake” lenses.

Holocake Lenses

Widespread present VR headsets together with Quest 2, PlayStation VR, and Valve Index use common refractive lenses, which necessitate a comparatively giant show panel and a big hole between it and the lens. This hole is the main driver of the dimensions and bulk of as we speak’s headsets.

In 2015 eMagin confirmed a particularly compact prototype HMD design utilizing what are referred to as “pancake lenses”. Pancake lenses use polarization to “fold” the optical path, making it a lot shorter. Final 12 months HTC shipped Vive Circulate, a compact USB powered headset utilizing pancake lenses. Meta’s “excessive finish” headset launching later this 12 months, nonetheless solely known as Venture Cambria, will use pancake lenses to attain a slimmer visor than Quest 2.

With Pancake lenses the optical path is brief sufficient that many of the remaining thickness is the lens itself. To cut back the dimensions of headsets even additional, Meta’s researchers stored the identical core ideas of pancake optics – polarization based mostly optical folding – however changed the curved lens with “a skinny, flat holographic lens”, constructing on analysis they confirmed off in 2020. Meta calls the end result “Holocake” lenses. To be clear, Meta makes use of the time period “holographic” otherwise than some others within the trade – that is holographic as in holographic movie, not a 3D gentle subject show.

Meta says a “very skinny prescription attachment” may be added to holocake lenses for these with decreased imaginative and prescient, eliminating the necessity to put on glasses contained in the headset.

Whereas Mirror Lake remains to be an idea, Meta has already constructed out a working prototype headset utilizing holocake lenses referred to as Holocake 2. Meta says Holocake 2 is a completely purposeful PC VR headset, able to enjoying any PC VR title. It calls Holocake 2 “the thinnest and lightest VR headset we’ve ever made”, and its researchers imagine additional miniaturization is feasible. In October Meta’s CTO Tweeted a picture of himself carrying what seems to be like Holocake 2.

Holocake lenses have an essential limitation – they require specialised lasers as the sunshine supply. LED backlights aren’t appropriate. Meta’s Michael Abrash famous that lasers aren’t but obtainable on the efficiency, measurement, and worth wanted for shopper merchandise. Utilizing lasers does nevertheless allow a a lot wider coloration gamut, Meta claims.

Reverse Passthrough

One roadblock to mass adoption of opaque digital and combined actuality headsets may very well be that others within the room can’t see your higher face & eyes. Whereas top quality coloration passthrough will allow you to see them, they’ll’t totally see you.

Final 12 months Meta researchers introduced a prototype of “reverse passthrough” – a headset with exterior LCD panels rendering a believable view of the wearer’s eyes. Mirror Lake would be the first totally built-in Meta prototype to function reverse passthrough.

Curiously, a report final month from The Info claims Apple’s upcoming headset will incorporate reverse passthrough, however including the screens apparently meant the outward going through cameras needed to be positioned in “awkward” positions far-off from the place the consumer’s eyes could be, making the event of passthrough reprojection algorithms tougher.