Flexible Circuit Adhesion Promoter Layer for Mechanical Stress
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Solution Overview
Problem
Flexible electrical circuits face reliability issues due to weak connections between electrically conductive structural elements, such as conductor tracks and contact layers, which can lead to damage and loss of electrical functionality under mechanical stress.
Innovation Solution
Incorporating a conductive adhesive layer with an adhesion promoter layer between the lacquer layer and the conductive adhesive, enhancing mechanical adhesion and ensuring a secure connection between the conductor tracks and contact layers, thereby improving the reliability of the electrical and mechanical connection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a simple adhesive layer is used to connect the conductor track and contact layer, then the manufacturing process is simple, but the connection reliability is poor and the structure is easily damaged under mechanical stress
Solution Approach 1:
The adhesive system is segmented into three distinct functional layers: a bottom adhesive layer for bonding to the carrier, a conductive adhesive layer for electrical connection, and a top adhesive layer for bonding to the contact layer. This segmentation allows each layer to be optimized for its specific function, resulting in improved overall connection reliability while maintaining manufacturing simplicity through a systematic layered approach.
Solution Approach 2:
The connection structure uses composite material design by combining different adhesive materials with complementary properties. The bottom adhesive layer provides strong mechanical bonding, the conductive adhesive layer provides electrical conductivity, and the top adhesive layer provides bonding capability. This composite approach resolves the contradiction by achieving high reliability through material composition rather than structural complexity.
2Reliability
If the conductor track and contact layer are directly connected without intermediate layers, then the structure is simple, but the electrical and mechanical connection is weak and prone to failure
Solution Approach 1:
The conductive adhesive layer acts as an intermediary between the bottom adhesive layer and the top adhesive layer, providing both mechanical bonding and electrical conductivity. This intermediary layer resolves the contradiction by enabling direct connection functionality while adding the necessary intermediate structure for reliable electrical and mechanical coupling, preventing connection failure under stress.
3Strength
If multiple adhesive layers are used to improve connection strength, then the adhesion is stronger, but the manufacturing process becomes more complex
Solution Approach 1:
The conductive adhesive layer performs multiple functions simultaneously: it provides mechanical bonding between layers, establishes electrical conductivity between the conductor track and contact layer, and contributes to overall structural integrity. This multi-functionality resolves the contradiction by achieving strong adhesion without proportionally increasing manufacturing complexity, as one layer accomplishes multiple objectives that would otherwise require separate components.
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 significantly reduces the failure rate of the connection under mechanical forces, providing a strong and reliable adhesion between the lacquer layer, electrical components, and conductor tracks, ensuring durable and stable electrical functionality.
Implementation Method 1
a layer of an adhesion promoter (50) is arranged on the at least one lacquer layer (10). The conductive adhesive layer (40) is positioned below the at least one electrically conductive contact layer (31) and above the layer of adhesion promoter (50)
Data Source
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AI summary
A flexible electrical circuit (2, 3) with connections between electrically conductive structural elements comprises at least one lacquer layer (10), at least one electrical conductor (20) arranged above the at least one lacquer layer (10), and at least one electrically conductive contact layer (31) for contacting at least one electrical component (32). The flexible electrical circuit further comprises a conductive adhesive layer (40) and a layer (50) of an adhesion promoter. The adhesion promoter layer (50) is arranged on the at least one lacquer layer (10). The conductive adhesive layer (40) is arranged below the at least one electrically conductive contact layer (31) and above the adhesion promoter layer (50).The layer (50) of adhesion promoter gives the flexible electrical circuit (2, 3) a high adhesive force between the at least one electrical component (32) and the at least one lacquer layer (10).