Foldable Display Backside Interconnect to Avoid Hinge FPC Fatigue
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Solution Overview
Problem
Foldable products with rotating shafts face reliability issues due to frequent bending of FPCs, affecting bending performance and hindering thinning designs, as the FPCs are prone to damage and integration affects the overall structure.
Innovation Solution
Integrate a mainboard connection structure at the back side of the display apparatus, using a wiring layer for interconnection between two mainboards without a through-going shaft connecting piece, ensuring signal transmission and reducing the overall thickness by transferring some lines to the back side of the display panel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If FPC is integrated on the rotating shaft to connect two mainboards, then electrical connection between mainboards is achieved, but bending performance deteriorates and reliability decreases due to frequent bending damage
Solution Approach 1:
The patent extracts the FPC from the rotating shaft location and relocates it to the back side of the display panel. This separation removes the FPC from the high-stress bending zone, allowing the rotating shaft to bend freely while the FPC remains protected and stationary, thus improving both reliability and bending performance
Solution Approach 2:
The patent transitions the FPC from a planar integration on the rotating shaft to a three-dimensional configuration on the back side of the display panel. This spatial repositioning allows the FPC to be routed through the housing structure, eliminating interference with the rotating shaft's bending motion and improving overall system reliability
2Reliability
If FPC is integrated on the rotating shaft, then interconnection between mainboards is achieved, but device thickness increases and thinning design is hindered
Solution Approach 1:
The patent utilizes the third dimension (depth/thickness) by routing the FPC through the housing structure from the back side of the display panel. This vertical routing allows the FPC to be concealed within the device thickness, achieving thinning design while maintaining reliable interconnection between mainboards
3Ease of operation
If FPC frequently bends with rotating shaft, then relative folding is achieved, but FPC is prone to damage and assembly requirements increase
Solution Approach 1:
The patent extracts the FPC from the rotating shaft assembly and relocates it to the back side of the display panel. This separation allows the rotating shaft to perform its folding function freely without subjecting the FPC to repeated bending, thereby improving FPC durability while maintaining folding functionality
Solution Approach 2:
The patent introduces the housing structure as an intermediary that protects the FPC. The FPC is routed through the housing, which acts as a protective tunnel, shielding the FPC from external damage and mechanical stress while allowing the rotating shaft to bend freely
Data Source
AI summary
A foldable display apparatus, a manufacturing method therefor, and a terminal device. The display apparatus includes a flexible display panel, a multi-layer protective structure, and a mainboard connection structure that is disposed inside the protective structure. The mainboard connection structure includes a metal wire disposed at a first protective layer of the protective structure, two ends of the metal wire respectively correspond to two screen areas of the display panel that are capable of being folded relative to each other, and are separately formed with bonding pads. Pad areas in which the bonding pads at the two ends of the metal wire are exposed are separately formed at the first protective layer. The bonding pads at the two ends of the metal wire are respectively electrically connected to two mainboards of the terminal device by using connecting pieces.