All smartphones look alike and it is difficult to get excited on their design (unless you are selling them …). So when a foldable phone, actually two of them, hits the market I can understand the big headlines.
Along with them, pretty sure you saw them, you are starting to see disappointed comments (surely about a very high pricing) on the fact that in reality it is not a foldable screen but a foldable shell having two screens. Hence, when you open it and flatten it out you get a crease in between them.
Now, the big price makes sense if you think that the screen is the most costly piece in a smartphone (see the graphic) although one should note that the margin on a smartphone is pretty high (70%) if you are just considering the BOM -Bill of Materials (that is not correct of course, but when you add one screen you are not really increasing significantly the other costs…).
The story is a bit different when you consider the complaints on the “crease” separating the two screens. Current technology simply does not support a really foldable screen that you are going to fold thousands of times. Take a look at the clip at the end of the post. You will see very nice and bright OLED displays that are folded less than 30°. The problem is that as you fold them more the stretching on the screen gets too much to bear.
You can fold the screen inward: that would result in a very tight folding, basically a line where the stretching and pressure reaches unmanageable levels. Or you can fold the screen outward and there you have two options. Either you design for a screen that is perfectly flat once it is unfolded, and in this case it will be stretched as it becomes curved (by a π factor, to be precise), or you have to mechanically separate the two halves of the phone once you open it up to accommodate the longer screen as it unfolds. Feasible, of course, but a bit tricky and possibly bulky. From a design point of view it makes sense to create a two screens smartphone with a tiny hinge.
Rumours are out on a possible Apple foldable phone, but those are just that, rumours. We’ll have to wait and see. It will surely be interesting to see and Apple design of such a phone and see what kind of solution they will use.
Personally, I think that a really foldable screen in the form factor needed for a smartphone is not happening any time soon (and of course I could be deadly wrong). More feasible would be a rollable screen….