Although the space on the back of the Samsung device shown in the patent that surfaced online thanks to Mobiel kopen might not be a secondary display after all, it is nice to think that a device similar to the YotaPhone might hit the market backed by the name of a major player in the smartphone market.
https://www.notebookcheck.net/New-Samsung-patent-shows-a-dual-screen-handset-similar-to-the-YotaPhone.309846.0.html