A patent application filed by Apple offers a look at the company’s ideas for wide field of view foveated augmented reality display technology.
Based on our reading of the patent the idea appears to be a direct evolution of Akonia’s technology. While the startup didn’t give details of how their technology worked, it called the approach ‘HoloMirror’ and claimed it had “dramatically higher” field of view than competitors with lower production cost. As far back as 2017 the company was claiming a 60 degree field of view.
The system described in the patent is rather complex. A laser array projector emits light into entrance points of an optical “distribution” waveguide. This waveguide then passes the light to exit points which lead to MEMS scanning mirrors. These entrance and exit points can either be implemented using holographic film or as surface relief gratings via lithographic techniques. The MEMS mirrors then direct the light into layered waveguides, where holographic projectors project it at a “focus curve” which reflects into a holographic combiner.
Crucially, some of the holographic projectors are “peripheral” projectors and the others are “foveal” projectors. Whereas the peripheral projectors direct low resolution imagery over 120 degrees horizontal field of view, the foveal projectors use higher resolution over an area of 20 degrees horizontal. The foveal image is sent to the position of the retina, which could be detected with eye tracking hardware. However, the patent notes that eye tracking may not be included to reduce complexity, in which case only peripheral projectors would be used.
This 120 degree field of view would be significantly wider than any current AR headset. No other company except Kura has claimed this kind of field of view in AR glasses. This would be wider than even most VR headsets. In fact, last week a Twitter user found code detailing the field of view of three potential Apple AR headsets. These three headsets had horizontal field of views of 47°, 46°, and 49° respectively. This could suggest the idea outlined in this patent is not going to be ready for a product in the near term.
The display technology detailed in this patent would also not be subject to the vergence-accommodation conflict, because it is a direct retinal projection system rather than a focused image. Apple notes this as a key design consideration in the patent.
As always, it is important to note that patents only rarely lead to real products. Companies like Apple explore many product and technology approaches, but ship only a small fraction of these ideas. And even if Apple does intend to build a product around this technology, this likely wouldn’t happen until several years in the future.
What patents like these, and recent leaks, do tell us is that Apple continues heavily investing in AR research. If Apple can bring compact AR glasses to market, it may come into direct competition with Facebook, which also has the same goal. Apple is almost always secretive about new products but it is possible we may see some early previews of Facebook’s technology this week at Oculus Connect 6.