Short · Phones
How does a folding phone's glass screen bend without breaking?
Bend glass and its outer surface stretches. Folded 2 mm tight, normal 0.5 mm phone glass would stretch about 12% and shatter; 30-micron glass stretches under 1%. And layers that slide bend far more easily than one glued slab.
Opens Folding Screen Lab. Change the same thing yourself.
Transcript
The new folding iPhone has glass in its screen, and it folds in half. Bend glass, and its outer surface stretches. Normal phone glass, folded this tight, would stretch more than ten percent and shatter. So foldable screens use glass about thirty microns thick, thinner than a hair, which stretches only about one percent. But Apple's screen is a stack of more than ten layers. Glued solid, they'd bend like one thick slab. Now let the layers slide. Each one bends on its own, and the strain drops. Try it yourself at Explainer Tools dot com.