Flexible PCB With Silane-Bonded Nanowires
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Solution Overview
Problem
Conventional flexible printed circuit boards (PCBs) face issues with workability and reliability in surface mounting and connector-bonding processes, and lack sufficient stretchability and durability against repeated bending stress.
Innovation Solution
A flexible PCB design featuring a first and second polymer substrate with metal nanowires between them, bonded by a cured silane coupling agent, providing flexibility, stretchability, and maintaining electrical conductivity even under repetitive bending.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a flexible PCB is made bendable to connect rigid PCBs, then adaptability and versatility are improved, but reliability and workability in surface mounting and connector-bonding processes deteriorate
Solution Approach 1:
The flexible PCB is segmented into multiple functional layers including a flexible substrate layer, a conductive pattern layer, and a protective coating layer. This segmentation allows each layer to be optimized independently - the substrate provides flexibility while the conductive patterns maintain electrical connectivity during bending, and the protective coating ensures bonding reliability.
Solution Approach 2:
The flexible PCB employs composite material construction combining flexible polymer substrates (such as polyimide or polyester) with rigid conductive traces and protective coatings. This composite structure enables the PCB to exhibit both flexibility for bending and sufficient rigidity for reliable surface mounting and connector bonding operations.
2Adaptability or versatility
If the PCB is made more flexible to enhance stretchability, then adaptability is improved, but durability against repeated bending stress deteriorates
Solution Approach 1:
The flexible substrate material parameters are carefully selected and optimized - using polymers with specific glass transition temperatures, elastic moduli, and tensile strengths that balance stretchability with bending durability. The conductive trace geometry parameters (width, thickness, pattern density) are also adjusted to maintain electrical performance across different bending states while withstanding repeated mechanical stress.
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 flexible PCB maintains minimal change in electrical conductivity and adhesive strength to the substrate, preventing delamination and damage from repeated bending, thus enhancing durability and workability.
Implementation Method 1
a cured silane coupling agent configured to bond the conductive track to at least one of the first polymer substrate and the second polymer substrate
Implementation Method 2
a conductive track including metal nanowires disposed between the first polymer substrate and the second polymer substrate
Implementation Method 3
a first polymer substrate having at least one of flexibility, stretchability, and elasticity; a second polymer substrate having at least one of flexibility, stretchability, and elasticity
Data Source
AI summary
A flexible printed circuit board (PCB) has stretchability and durability. The flexible PCB includes: a first polymer substrate having flexibility, stretchability, or elasticity; a second polymer substrate having flexibility, stretchability, or elasticity; a conductive track disposed between the first and second polymer substrates and including metal nanowires; and a cured silane coupling agent which bonds the conductive track to at least one of the first and second polymer substrates.