A newly granted Microsoft patent, however, look to solve the display crease problem with an innovative hinge mechanism beneath the display. The patent, which was first discovered by Windows United, is entitled “Moveable display supports, computing devices using same, and methods of use” and was granted on June 6th, 2019.
The patent describes two different methods for folding displays, but both have the same general purpose -- to maintain a predetermined folding radius in an effort to eliminate the display crease. "The computing device includes a flexible display including a thin film transistor matrix having a front surface and a back surface," writes Microsoft when talking about its first implementation for a folding display.
"A moveable display support is included and is connected to the back surface of the display and is configured to limit bending in one direction to a first bend radius while maintaining strain on the thin film transistor matrix below a predetermined amount of strain by elongating the moveable display support during bending."
For the second implementation, Microsoft writes, "The computing device includes a flexible display having a front surface and a back surface. The computing device includes a moveable display support connected to the back surface of the display. The moveable display support is formed by a plurality of unit cells."
The first method, seen in Figure 9 through Figure 10, uses an interlocking lattice structure that conforms to the back of the display. The second method (Figure 16 and 17) uses a serious of interlocking hinge arms to achieve the same effect. You can see the full patent filing here.
Microsoft doesn't seem toi interested in getting back into the smartphone fray, and is content in providing its software and services to iOS and Android devices. But the company has reportedly shown off a dual-display Surface computer behind closed doors. If that device does come to fruition, a future Surface device with a single-piece folding display seems like an inevitable successor.