Stretchable PCB Interconnect for Strain-Resistant Electrical Coupling
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Solution Overview
Problem
The challenge lies in establishing a robust electrical interconnection between stretchable electronic elements and rigid or flexible circuit boards, as existing methods often result in compromised connections due to differences in stretchability, leading to unreliable measurements or system failure, especially in applications where the interconnection must withstand strain and maintain electrical integrity.
Innovation Solution
The solution involves creating an interconnect system that includes stretchable electronic elements with compliant conductive electrodes and dielectric layers, where the interconnect features landing pads and conductive polymers, and the use of adhesive or fasteners to secure the circuit board to the substrate, minimizing bulk support material and maintaining stretch capabilities, while ensuring electrical coupling between the stretchable and rigid components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If stretchable electronic elements are directly connected to rigid circuit boards, then electrical connection is established, but connection reliability deteriorates due to differential stretching and mechanical stress
Solution Approach 1:
The patent introduces an intermediary interconnect structure comprising a substrate with conductive pathways that couples the stretchable electronic element to the rigid circuit board. This intermediary component absorbs mechanical stress and accommodates differential stretching, preventing direct stress transmission between the stretchable sensor and rigid PCB, thereby maintaining connection reliability without excessive complexity
Solution Approach 2:
The interconnect structure utilizes materials and designs that change their mechanical parameters (flexibility, stretchability) to match the operational requirements. The substrate and conductive pathways are designed with specific elastic moduli and geometric configurations that allow controlled deformation under stress, enabling reliable electrical connection while accommodating the stretchable nature of the electronic element
2Strength
If support material is added to reinforce the interconnect, then mechanical strength is improved, but the bulk and stiffness increase reducing stretch capabilities
Solution Approach 1:
The interconnect structure applies reinforcement selectively only where mechanically necessary. Support material or structural features are concentrated at critical stress points such as the bonding interface between the stretchable electronic element and the interconnect substrate, or at the interface between the interconnect and rigid PCB, while leaving other regions lightweight and flexible to maintain overall stretch capability
Solution Approach 2:
The interconnect employs composite material structures combining materials with different mechanical properties. This may include layered composites of flexible substrates with embedded conductive traces, or hybrid materials that provide both mechanical strength and flexibility, enabling the interconnect to achieve adequate strength without excessive bulk that would compromise stretch capabilities
3Adaptability or versatility
If the interconnect is made more flexible to accommodate stretching, then stretch capability is improved, but electrical connection stability deteriorates under mechanical stress
Solution Approach 1:
The interconnect structure is designed with dynamic characteristics that allow it to adapt its stiffness during operation. The substrate and conductive pathways can deform elastically under stretching conditions while maintaining electrical continuity, and return to their original configuration when stress is released, ensuring stable electrical connection throughout the stretching cycle
Solution Approach 2:
The interconnect employs nested or layered structures where conductive pathways are embedded within or protected by substrate layers. This nested configuration provides mechanical protection to the electrical pathways while allowing the overall structure to flex and stretch, maintaining electrical connection stability without compromising stretch capability
Data Source
AI summary
One aspect of the invention provides an interconnect between a stretchable electronic element and a circuit on a rigid or flexible printed circuit board (PCB Circuit), the stretchable electronic element is operable to be mechanically coupled to a substrate which deforms, and the stretchable electronic element will deform with the substrate and may or may not change an electrical characteristic as a result, the stretchable electronic element comprising one or more electrical pathways; the PCB Circuit configured to communicate electronically with the stretchable electronic element and comprising at least one circuit board extending from the stretchable electronic element to an electrical circuit on the PCB Circuit; wherein the interconnect comprises an electrical coupling between the electrical pathways of the stretchable electronic element and the PCB Circuit; and wherein the interconnect simultaneously prevents the connection between the stretchable electronic element from failing when the stretchable substrate is stretched in normal operation, minimizes the bulk of support material required to support the interconnect, and minimizes any reduction in the stretch capabilities of the stretchable substrate.