Stretchable RFID Tags With Adhesive Stress Absorption
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Solution Overview
Problem
Conventional RFID tags lack the necessary flexibility and stretchability for applications such as wearable devices, requiring modifications to the RFID device itself to accommodate increased usability demands.
Innovation Solution
The development of stretchable RFID tags with flexible substrates and adhesive layers that absorb stresses, allowing the electronic circuit to remain protected and unstressed, either by attachment at discrete points, internal cavity placement, or within a pocket, enabling flexibility and stretchability without modifying the RFID device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional RFID tags are used, then the electronic circuit is protected and functional, but the tag lacks flexibility and stretchability for wearable applications
Solution Approach 1:
The RFID tag is segmented into distinct functional layers: a flexible substrate layer for stretchability, an adhesive layer for stress absorption, and an electronic circuit layer for functionality. This segmentation allows each layer to perform its specialized function independently, enabling the tag to be stretched while protecting the electronic circuit.
Solution Approach 2:
An adhesive layer is introduced as an intermediary between the flexible substrate and the electronic circuit. This intermediary layer absorbs stresses during stretching, preventing direct transmission of mechanical stress to the electronic circuit components, thereby maintaining circuit integrity while enabling flexibility.
2Adaptability or versatility
If the RFID device is modified to increase flexibility, then adaptability improves, but device complexity increases
Solution Approach 1:
The RFID tag employs a flexible substrate and thin adhesive layers to achieve stretchability without complex mechanical structures. This approach uses material properties rather than complex mechanisms, maintaining simplicity while enabling flexibility and adaptability for wearable applications.
3Device complexity
If the electronic circuit is directly attached to the substrate, then device complexity is reduced, but the circuit undergoes excessive strain during stretching
Solution Approach 1:
The adhesive layer serves as a stress-absorbing intermediary between the substrate and electronic circuit. It decouples the mechanical deformation of the substrate from the electronic circuit, allowing the substrate to stretch while the circuit remains relatively strain-free, thus reducing stress without adding significant structural complexity.
4Stress or pressure
If discrete attachment points are used, then stress absorption improves, but manufacturing precision requirements increase
Solution Approach 1:
The adhesive layer exhibits local quality variations with a thicker border region and thinner interior region. This local differentiation optimizes stress distribution: the thicker borders provide enhanced stress absorption and anchoring, while the thinner interior allows circuit placement with reduced stress exposure, balancing stress absorption with manufacturing feasibility.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution provides a flexible and stretchable RFID tag that maintains the integrity of the electronic circuit, allowing it to function effectively across various substrates and surfaces, including human skin, without requiring modifications to the conventional RFID device, ensuring consistent performance and durability.
Implementation Method 1
an adhesive layer disposed on a major surface of and substantially coextensive with the first substrate, the adhesive layer having a thicker border region and a thinner interior region
Implementation Method 2
a second substrate spaced apart from the first substrate and attached to the first substrate at a finite number of discrete spaced apart attachment locations, the attachment locations defining an air gap between and substantially coextensive with the first and second substrates
Data Source
AI summary
Flexible, stretchable RFID tags are formed by a pocket that is formed from one or more substrates and layers of adhesive, and an electronic circuit that is located within this pocket. The RFID tags can include a stretchable substrate and an electronic circuit attached to the stretchable substrate by one or a finite number of discrete spaced apart attachment locations. When the pocket is formed by relatively thick adhesive layers adhering together one or more flexible substrates to form an internal cavity, the electronic circuit is located within this cavity and either is not adhered to any of the substrates of the cavity, and is free to move about within the cavity, or the electronic circuit can be attached to a substrate by a thin layer of adhesive.