Obviously they won't have a screen anymore. They'll be pop-up displays. So if you're sitting on a train and your romantic partner sends you a steamy selfie...guess who has an audience?
Has this annoyed anyone else?
If they're tactical screens, that makes sense. But I still don't think transparent displays on personal devices will be a thing in the future.
I think all display tech is gonna gravitate towards VR or AR in a few decades. We're about to hit a plateau of digital advancement. At least for hardware.
I know everyone likes to tout VR, but I really think that AR will be the sweet spot most people ultimately adopt. Add it into nice looking glasses (sorry Google Glass, not it) and have some sort of easier to use interface that can interact with your surroundings and that will take off.
Imagine being in a business meeting with a little pop up over each person's head with their name, title and other interesting information you need to know. Or be at a baseball game and have similar stats pop up above each player's head. Turn by turn directions overlaid directly on the street. There are endless possibilities (as long as the ads don't get in the way, but even for them, imagine green screen billboards that can display unique ads too).