https://phys.org/news/2021-05-arvr-glasses.html According to the article it was not easy to make, but its the first of its kind and is targeted at an enormous market, and could easily make every existing VR headset obsolete overnight. They used electron beam lithography to half carve the damned thing and get the optics to mate with the flat lens, which means the first models could be ridiculously expensive. Headsets capable of doing what this one does commonly cost as much as a hundred thousand dollars, and are enormous affairs on gimbles or whatever. The flat lens or metasurface means a spot the size of a tiny grain of rice on an ordinary pair of glasses, can consolidate all of the optics and feed them directly into your eyeball, providing either VR and AR. Feeding the light directly into your eyeball, allows you to focus on objects in VR, the same way you do in the real world. When watching something 2D like a video in VR, its roughly the equivalent of watching a 50" TV from six feet away.
Fresnel lenses are commonly used in virtual reality headsets due to their compactness and lightweight structure. The lenses do not use multiple pieces of material in their lenses like other lenses (lens plural), but the lens will be broken down into sections, allowing the individual to have a wider range of view.
Because it ends with an 'S', lens is the plural and third person of itself. You listen to Beethoven's piano concerto, but a Brahms not Brahmses works. When the BBC were introducing the prom's some years ago, an announcer made this mistake. My late mother, who was 96 at the time, phoned the BBC and told them that their announcer was an illiterate idiot.
