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Lots of excitement and disappointment on foldable phones

The ads image used by Samsung for its new Galaxy Fold. A colourful butterfly nicely shows up on the two halves of the screen, hiding the fact that it is not one screen but two of them joined together. Image credit: Samsung

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 cost of smartphones components of the iPhone X and Samsung Galaxy S8. Notice that the cost of the screen is the most significant one. Graphic credit: Figures released by IHS Markit / © AndroidPIT

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….

About Roberto Saracco

Roberto Saracco fell in love with technology and its implications long time ago. His background is in math and computer science. Until April 2017 he led the EIT Digital Italian Node and then was head of the Industrial Doctoral School of EIT Digital up to September 2018. Previously, up to December 2011 he was the Director of the Telecom Italia Future Centre in Venice, looking at the interplay of technology evolution, economics and society. At the turn of the century he led a World Bank-Infodev project to stimulate entrepreneurship in Latin America. He is a senior member of IEEE where he leads the Industry Advisory Board within the Future Directions Committee and co-chairs the Digital Reality Initiative. He teaches a Master course on Technology Forecasting and Market impact at the University of Trento. He has published over 100 papers in journals and magazines and 14 books.