Samsung has captivated some tech enthusiasts with its Galaxy Z Flip neo-clamshell phone, the second of its kind to be foldable. Now, a different mobile device company, OPPO, has designed one much like it, but in reverse. Its screen is on the outside, with a sensor that detects the angle at which it is unfolded.
https://www.notebookcheck.net/OPPO-patents-a-clamshell-foldable-phone-with-the-screen-on-the-outside.490927.0.html