The need for bigger screens while also remaining portable has led to the development of foldable smartphones and so far, the results have been satisfactory at best to really unimpressive for the masses. It being priced so high doesn't help either that they cost a lot. Which is why this new prototype from TCL is doing away with the foldable mechanism and is using a sliding mechanism instead.
CNET had revealed the photos for this foldable phone, revealing a standard phone that turns into a tablet once you've pulled out the screen from the side. It was meant to be revealed during MWC 2020 but unfortunately the event had been cancelled due to the coronavirus.
According to CNET, "... the design of this TCL concept phone appears to use one continuous display, with curved screens on either side. Between the center of the phone and the dual front-facing camera along the right side, there's a break in the chassis where you can pull the two sides apart to expose the surplus screen. It'd be much like sliding back the sides of your dining room table to add a leaf that seats more guests."
It looks like one part of the display will be flexible enough to bend and wrap behind the main screen. As such, the device is expected to be a lot thicker than usual.
TCL actually has their own foldable concept phones of its own, but it looks like they aim to do something different than just folding a smartphone or a tablet to get that bigger screen. Hopefully the slide out technique pans out and is a lot more affordable than the current generation of foldable smartphones.