How do foldable screens work on Note and Fold-type devices?

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The core of foldable displays lies in two ultra-thin flexible OLED panels and a flexible substrate made of either UTG (ultra-thin glass) or polyimide (PI) film. The organic light-emitting layer of the flexible OLED can remain continuous when bent because its pixels are deposited as a film on the flexible substrate. When stressed, the force is primarily distributed across the substrate rather than individual pixels, preventing issues like "cracks" or "failures." When I disassembled a Galaxy Fold, I found a protective polymer adhesive layer between the panel layers, which acts as a buffer during bending, further reducing stress concentration. As for the hinge mechanism, there are two main designs on the market: single-axis hinges and multi-axis elastic hinges. Single-axis hinges, similar to traditional laptop flip covers, use metal brackets and springs to provide rotational damping. Multi-axis hinges incorporate micro-cams and ball bearings inside the brackets, making the folding process smoother and automatically calibrating screen tension when unfolded. Inside the hinges, there are also magnetic positioning blocks and optical sensors that help the system determine whether the screen is in a folded, semi-folded, or fully unfolded state. This allows the software to switch UI layouts and recalibrate the touch matrix accordingly. In actual use, I noticed that when the screen quickly unfolds from a folded state, the system completes touch calibration within milliseconds. This is thanks to real-time position data from hardware sensors and dynamic remapping of touch capacitance at the driver level. Overall, flexible materials, intricate hinge structures, and collaborative calibration algorithms between hardware and software ensure that foldable screens maintain visual coherence and touch sensitivity even after multiple folds.