One version has screens on the inside and closes like a book.
Instead of sporting two screens on the outside and one on the inside, this concept design has an LED clock.
The back could have something like a light-up clock.
This foldable concept device doesn't close completely. It leaves a bit of a lip that could be used for a small notifications screen.
TCL only allowed the prototypes to be photographed under glass.
TCL showed off sketches of other possible foldable devices.
Here's a close up.
You can see more sketches here.
Another model closes more like a flip phone.
The prototypes use custom flexible AMOLED displays from TCL's sister company China Star Optoelectronics Technology (CSOT).
TCL doesn't expect to launch any foldable devices until 2020.
TCL's prototype lets different apps run on the two sides of the screen.
Check out a few more shots.