Foldable Display Optical Layer Layout for Bend Wire Reliability

The patent introduces a third dimension by forming a protrusion structure that extends upward from the substrate surface in the bending area. This vertical dimension provides additional space for wire routing and stress accommodation, allowing the wires to be positioned away from the high-stress bending region while maintaining compact lateral dimensions. The protrusion creates a neutral plane that protects wires from stress concentration during bending operations.

The patent employs curved surfaces by forming a protrusion with a rounded top surface instead of sharp edges. This curvature distributes stress more evenly across the wire routing path and prevents stress concentration points that would otherwise lead to wire disconnection. The smooth transition of the curved surface allows for better stress management during device bending while maintaining the reduced non-display area width.

The patent utilizes a composite structure combining the substrate material with a protrusion structure made of different materials having complementary properties. The protrusion can be formed from materials with higher mechanical strength or different thermal expansion coefficients, creating a composite system that maintains overall thinness while providing localized structural reinforcement where needed, particularly in the bending area where wires are routed.

The curved top surface of the protrusion structure distributes mechanical loads more effectively across the thin device profile. The rounded geometry prevents stress concentration at sharp edges and provides a gradual transition that enhances structural integrity despite the reduced overall thickness. This curvature allows the thin structure to better absorb and distribute bending stresses.