I was hoping, this being Wired, the article would have at least a surface-level technical description of how a software-defined privacy filter works, but alas.

How does it work? I'm guessing it's some kind of extension of the LCD polarizer, but all I can find online are explanations of the software like in the Wired article.

Its not a filter or layer, its the pixels themselves. Half are normal wide viewing angle pixels, the other half are pixels with a much more narrow viewing angle. When activated they just ... switch off the normal ones.

See for example:

https://gsmarena.com/samsung_galaxy_s26_ultra-review-2939p3....

Or from the official Samsung presentation:

https://youtube.com/shorts/qnUVGPkeCCc

Basically half of the pixels have a narrow view angle, the others don't, when you activate the privacy mode, only the narrow pixels remain, so you can see the screen only looking straight.

I got this explanation for the mkbh video: https://youtu.be/nfHRMqqO578?t=141&si=iEhVrdCuLN0fkasd which illustrates it very well (2m24 if timestamp doesn't work)

Theyre not polarized, the pixels are recessed so that the light only goes forward

I wonder if this is how those privacy screen protectors work. Where it's just like looking at the screen through a cell structure with walls that prevent light coming out at an angle.

Right ! My bad