T420 display among the worst I've ever seen :-(

[Colonel O'Neill]

Curious: What about a TN display changes it's viewing angle within the TN class? I'm guessing it's the thickness of the crystal layer and something about the quarter spiral arrangement?

[penartur]

Scientific fact it would instantly cure all problems anyone has with LCD. Viewing angles are a simple matter of how a pixel emits its light. TN throws it all 0' forward, and any deviation changes what you see, where as IPS throws it around more evenly (think, shining a flashlight into a fisheye, as opposed to a zoom lens), OLED is akin to just having the lightbulb emitting with no lens or limits.

Basically, OLED emits light by its own, while LCD just filters out the light emitted by its backlight. And the filtered light don't just disappear.

[ThinkRob]

Curious: What about a TN display changes it's viewing angle within the TN class? I'm guessing it's the thickness of the crystal layer and something about the quarter spiral arrangement?

Aperture size. There are wide-aperture TN panels which have viewing angles that are almost as good as those of IPS displays. They're pretty uncommon since tablets tend to just use IPS/AFFS/PVA/MVA anyways, but they do exist.