Can AR glasses be used as just a monitor? I am under the impression that they are sort of smart devices. How do they get a video signal from the computer?
The new "One" unit referenced in this review is the same but does have some smarts to do on-glasses processing of the virtual displays itself instead, if I understand it.
Xreal also sells you some companion devices that are just little Android bricks to cast media to and from and play things from as well.
Instead, you need resolution in terms of Pixels Per Degree (PPD). And, to have any hope of viewing legible text on a virtual monitor projected via an AR HUD, like you can on a physical laptop monitor, you need at least 35PPD.
I realize there’s been a decade of progress. However, seeing random no-name AR glasses and being encouraged to buy them “sight-unseen” by a native content article seems like a recipe for being bamboozled.
I tried with my Xreal Air on Windows and macOS, and yes, it's quite legible.
Do bear in mind that although the screen is quite close to your eyes, the optics makes the apparent distance quite far. So if you're short-sighted, you will need prescription inserts. I also have some issues with some corners of the screen being slightly cut off, probably a combination of the inserts which I ordered locally as well as the fixed IPD of the older Xreal glasses (the newer Xreal One should be better here with its software IPD adjustment, the Xreal One Pro also comes in two different sizes for different IPD ranges). I also noticed some of the text on the right side of the Word ribbon was a bit blurry, which might be due to the inserts. But in general, I find the display quality great for video, and perfectly good for web browsing (not as good as a Hi-DPI display, but perfectly usable).
For better or for worse - and I personally think it's very much for the better - many AR glasses are a DisplayPort monitor that you wear on your face. They have inertial sensors and speakers, but the interface to the PC is Displayport-over-USBC for video to the glasses, USB Audio Class for the speakers, and usually a proprietary USB peripheral for the inertial measurements.
Some AR glasses attempt to require being paired with a dedicated video phone-like device, largely to attempt to extract subscription revenue. Most do not.
It's perfectly possible to drive a pair of AR glasses from an Android smartphone, a video-game-focused SBC, or a miniPC. Anything with DisplayPort video out at 1080p or better (3840x1080 if you want 3D videos).