Wearable Meander Interconnects with Bonding Openings
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Solution Overview
Problem
Existing wearable sensor designs face limitations in stretchability and reliability due to constrained meander interconnects during the lamination process, which affects their ability to adapt to body movements and maintain skin contact, essential for continuous physiological parameter monitoring.
Innovation Solution
A wearable system with a flexible circuit board sandwiched between a base and top layer, where the meander section is not bonded, allowing for increased freedom of deformation and reliability, and is encapsulated to prevent damage, using a bonding layer with openings around the meander section to prevent constraining deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the meander section is bonded during lamination to ensure structural integrity, then manufacturing reliability is improved, but stretchability and freedom of deformation are reduced
Solution Approach 1:
The bonding layer is segmented into two distinct regions: a first region that bonds the top and base layers together to provide structural integrity, and a second region that leaves the meander section unbonded to allow stretchability. This spatial segmentation resolves the contradiction by applying bonding only where structural support is needed while preserving flexibility in the meander region.
Solution Approach 2:
Different bonding characteristics are applied to different parts of the device: the first region has strong bonding for structural stability, while the second region has no bonding to enable deformation. This local differentiation allows the device to simultaneously achieve both reliability and adaptability in different functional zones.
2Adaptability or versatility
If the meander section is left unbonded to maintain stretchability, then adaptability to body movement is improved, but structural integrity and manufacturing reliability are reduced
Solution Approach 1:
The bonding layer is divided into bonded and unbonded regions, creating a hybrid structure where structural integrity and stretchability coexist in different spatial zones of the same device.
Solution Approach 2:
The device employs a composite bonding structure combining bonded regions (for integrity) and unbonded regions (for flexibility), effectively creating a composite material system at the structural level that exhibits both rigidity and flexibility properties.
3Strength
If full lamination is used to encapsulate and protect the flexible circuit board, then device durability is improved, but the meander interconnects are constrained and cannot deform freely
Solution Approach 1:
The encapsulation is segmented into a first region covering the rigid components for protection and a second region leaving the meander section exposed for free deformation, resolving the conflict between protection and flexibility.
Solution Approach 2:
Different levels of encapsulation are applied locally: full encapsulation in the first region for durability, and no encapsulation in the second region for deformation freedom, allowing the device to have both protective coverage and flexible movement capability.
Data Source
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AI summary
A wearable system is for mounting against the skin of a subject. It comprises a flexible circuit board sandwiched (e.g. laminated) between a top layer and a base layer. The flexible circuit board has a meander section between end pads. The base layer and the top layer are bonded together by a bonding layer which has a meander opening around the meander section. This means the stretchability of the meander section is not inhibited by the lamination process.