Stretchable Metal Foil Wiring Substrates
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Solution Overview
Problem
Existing stretchable members with metal foils face challenges in forming flexible wiring substrates with good adhesion, particularly when used on curved body surfaces or joints, due to inadequate stretchability and adhesion properties.
Innovation Solution
A stretchable member comprising a stretchable resin base material combined with a conductive metal foil having a roughened surface with surface roughness between 0.1 μm to 3 μm, enhancing adhesion and allowing for the formation of flexible wiring substrates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a smooth metal foil is used, then the manufacturing process is simple, but the adhesion between metal foil and resin base material is poor
Solution Approach 1:
The invention changes the surface parameter of the metal foil from smooth to roughened, specifically controlling the surface roughness Ra to be 0.1 μm to 3 μm. This parameter change increases the adhesion strength between the metal foil and resin base material while maintaining manufacturing simplicity through established roughening techniques.
Solution Approach 2:
The invention creates a roughened surface structure on the metal foil that resembles a porous or micro-structured surface. This roughened surface provides increased surface area and mechanical interlocking capability, enhancing adhesion between the metal foil and the stretchable resin base material.
2Strength
If a roughened metal foil surface is used, then the adhesion between metal foil and resin base material is excellent, but the manufacturing process becomes more complex
Solution Approach 1:
The invention specifies a controlled range for surface roughness (Ra: 0.1 μm to 3 μm) that balances adhesion performance with manufacturing feasibility. This parameter optimization ensures excellent adhesion while allowing the use of standard industrial roughening processes, avoiding excessive manufacturing complexity.
3Adaptability or versatility
If the stretchable member is made more flexible, then it can be used on curved surfaces and joints, but the adhesion between metal foil and resin base material deteriorates
Solution Approach 1:
The roughened surface structure on the metal foil creates mechanical interlocking that maintains adhesion strength even when the stretchable resin base material is deformed. The micro-roughness features allow the adhesive resin to penetrate and anchor into the surface, preserving bond strength during stretching and bending operations.
Solution Approach 2:
By optimizing the surface roughness parameter (Ra: 0.1 μm to 3 μm), the invention achieves a balance where the metal foil maintains excellent adhesion to the stretchable resin while allowing the resin to exhibit its full flexibility and stretchability range for use on curved surfaces and joints.
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 enables the simple manufacturing of stretchable wiring substrates with excellent adhesion between the metal foil and the resin base material, improving flexibility and resistance to repeated use.
Implementation Method 1
A surface of the metal foil on the stretchable resin base material side is a roughened surface having surface roughness Ra of 0.1 μm to 3 μm
Data Source
AI summary
Disclosed is a stretchable member with a metal foil including a stretchable resin base material, and a conductive metal foil provided on the stretchable resin base material. A surface of the metal foil on the stretchable resin base material side is a roughened surface having surface roughness Ra of 0.1 μm to 3 μm.