Microsoft's prototype smartphone replaces secondary display with e-ink cover

Before the first true foldable smartphones make their market debut next year, some companies are still flirting with the idea of dual-screen phones. ZTE's dual-screen Axon M missed the opportunity of becoming a market success, even though it was the first of its kind.

The ZTE Axon M with two displays sounds like a good idea on paper, but the execution leaves to be desired. Microsoft, however, tackled the dual-screen theme completely differently, although we're not sure that it's going to see the light of day.

Spotted recently on Twitter, Microsoft Research's Lumia 640 prototype ...