If the patent does turn out to be the rumoured Surface device then its a bit silly to call it a 'Phone'
What name would you give this?
Could this be the Surface Phone? Microsoft awarded patents for a range of foldable mobile devices | Page 2 | Windows Central
Off the top of my head id call it a Surface Bone
The folding graphene OLED screen was co-developed by Samsung, and Microsoft, and they no doubt both have plenty of patents on specific designs. Manufacturing cost of graphene is the major obstacle. A single screen ATM costs thousands of dollars to produce. It won't be till we create new ways of making this super material that we will see folding screens.
However, the surface phone will most certainly be a full PC. Therefor calling it a "smartphone" seems demeaning if anything. The word Microsoft themselves have been floating about, like at the windows on arm demo was "Mobile PC". And I believe that is the catergory name that is appropriate for a slab phone.
Regarding future folding graphene screens -
I suspect when this actually comes (5-10 years probably, and initially only for the uber rich), a word like phablet, or tablet book, would be repuposed. Even "book", despite its use in laptops. People shy away from complex words. Hence "laptop", PC, smartphone, tablet. They are all pretty simple words. Initially it will be branded something fancy like, but in the end, it will probably be reduced to words like "book" "scroll" or whatever thing it looks like.