Foldable FPCB Layout for Impedance-Stable Signal Transmission
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In foldable electronic devices, signal lines on flexible printed circuit boards (FPCBs) connecting different housings are prone to signal loss due to impedance sensitivity, leading to performance deterioration.
Innovation Solution
Implementing a design with multiple flexible printed circuit boards, each with separate signal lines, to minimize impedance influence and prevent timing skew or delay, without additional wiring.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a flexible printed circuit board is disposed between components to enable signal transmission through a folding portion, then signal transmission is maintained during folding, but the insulating layer may be damaged and electrical shorts may occur
Solution Approach 1:
The patent applies beforehand cushioning by placing a protective layer over the insulating layer at the folding portion before the damaging action occurs. This protective layer prevents direct contact and damage between the conductive pattern and external objects during folding, cushioning the insulating layer against potential punctures or shorts before they can happen.
Solution Approach 2:
The patent uses an intermediary approach by introducing a protective layer as a mediator between the conductive pattern on the flexible printed circuit board and the external environment. This intermediary layer transfers the mechanical stress away from the insulating layer, allowing folding while protecting the electrical components from direct damage.
2Adaptability or versatility
If the flexible printed circuit board is folded to connect front and rear housings, then device compactness and flexibility are improved, but contact between the conductive pattern and external object may cause electrical shorts
Solution Approach 1:
The protective layer serves as an intermediary barrier between the conductive pattern and external objects. This mediator allows the flexible printed circuit board to maintain its adaptability for folding while preventing harmful direct contact that could cause electrical shorts, thus preserving reliability during flexible operation.
Solution Approach 2:
The patent employs a thin film protective layer that conforms to the flexible nature of the circuit board. This flexible shell protects the conductive pattern without restricting the folding motion, maintaining the device's versatility while ensuring electrical safety through the protective barrier.
3Ease of operation
If the flexible printed circuit board is disposed along the folding portion, then signal transmission between front and rear housings is enabled, but the insulating layer is vulnerable to damage
Solution Approach 1:
The protective layer is applied beforehand to cushion the insulating layer at the vulnerable folding portion. This allows the flexible printed circuit board to maintain its ease of operation for signal transmission while the protective layer预先 protects against durability issues during repeated folding operations.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
According to an embodiment, it is possible to provide an electronic device including: a housing; a first printed circuit board disposed in the housing; a second printed circuit board disposed in the housing and spaced apart from the first printed circuit board; a first flexible printed circuit board electrically connecting the first printed circuit board and the second printed circuit board; and a second flexible printed circuit board electrically connecting the first printed circuit board and the second printed circuit board, in which the second flexible printed circuit board may be longer than the first flexible printed circuit board. Other embodiments are also disclosed.