Thermoformed Conductive Traces for Stretchable Electronics
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Solution Overview
Problem
Conductive traces in stretchable electronics experience changes in electrical resistance due to stress from substrate deformation, leading to hysteresis and susceptibility to changes after multiple stretching events.
Innovation Solution
A method involving the deposition of thermoformable conductive ink on an elastomeric substrate, followed by thermoforming while heated, allowing the substrate and ink to cool, and then releasing the deformation, resulting in buckled conductive traces that maintain constant electrical resistance upon stretching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conductive traces are deposited on an elastomeric substrate for stretchable electronics, then the device can be stretched and deformed, but the electrical resistance of the conductive traces changes due to stress from substrate deformation
Solution Approach 1:
The conductive trace is pre-stretched during the curing process before the substrate is stretched during use. This preliminary deformation allows the trace to accommodate subsequent stretching without significant resistance change, as the trace has already been prepared to handle the expected mechanical stress
Solution Approach 2:
The patent changes the physical state of the conductive trace material by controlling its temperature during curing. The trace is cured at an elevated temperature above the glass transition temperature of the polymer, which allows the polymer chains to move and align with the stretched substrate, thereby maintaining electrical conductivity during deformation
2Reliability
If the conductive trace material is cured at elevated temperature, then the polymer chains can align with substrate stretching, but the curing process requires precise temperature control above glass transition temperature
Solution Approach 1:
The patent utilizes the glass transition phase transition of the polymer material. By curing the conductive trace at a temperature above the glass transition temperature, the polymer chains gain mobility and can align with the stretched substrate configuration. This phase transition approach provides a clear thermal threshold for processing
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 method ensures that conductive traces do not experience changes in electrical resistance during large substrate stretching, maintaining reliable performance across multiple stretching events.
Implementation Method 1
heating the sub-portion of the elastomeric substrate and conductive trace material deposited on that sub-portion to a first predetermined temperature
Implementation Method 2
deforming the sub-portion of the elastomeric substrate and conductive trace material to a second topological configuration
Implementation Method 3
The sub-portion can be deformed into the second topological configuration by applying a strain or force thereto
Implementation Method 4
allowing the sub-portion of the elastomeric substrate and conductive trace material deposited on that sub-portion to cool to a second predetermined temperature whilst in the second topological configuration
Implementation Method 5
The method can further comprise releasing the strain applied on the sub-portion once it has cooled to the second predetermined temperature, thereby enabling the sub-portion of the substrate to revert to the first topological configuration
Data Source
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AI summary
A method of forming a conductive trace, the method comprising depositing a conductive trace material on a portion of an elastomeric substrate, a sub-portion of the elastomeric substrate comprising a first topological configuration, heating the sub-portion of the elastomeric substrate and conductive trace material deposited on that sub-portion to a first predetermined temperature, deforming the sub-portion of the elastomeric substrate and conductive trace material to a second topological configuration, and allowing the sub-portion of the elastomeric substrate and conductive trace material deposited on that sub-portion to cool to a second predetermined temperature whilst in the second topological configuration.