Stretchable Circuit Board Stress Distribution
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Solution Overview
Problem
Existing stretchable circuit boards face issues with stress concentration and wire breakage at the outer circumference of covering portions, leading to potential division of stretchable conducting films when subjected to tensile forces.
Innovation Solution
The design incorporates a stretchable circuit board with a covering portion that has lower stretchability than the conducting film, creating a larger area on the outer circumference to distribute stress evenly, and optionally includes reinforcing materials to prevent deformation and stress concentration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a covering portion is provided to cover terminals of electronic components, then the electronic components are protected, but stress concentration occurs on the outer circumference of the covering portion causing wires to break
Solution Approach 1:
The patent applies local quality by making the stretchable conducting film thicker specifically at the first section (outer circumference of covering portion) compared to the second section (other areas). This localized thickness variation provides enhanced strength where stress concentration occurs, while maintaining overall stretchability of the circuit board.
Solution Approach 2:
The patent changes the physical parameter of the stretchable conducting film by varying its thickness across different sections. The first section has a greater thickness than the second section, which alters the mechanical properties locally to resist stress concentration at the covering portion's outer circumference.
2Adaptability or versatility
If the stretchable conducting film has high stretchability, then the circuit board can be stretched, but the film is easily divided at the first section where stretchability changes largely
Solution Approach 1:
The patent applies local quality by creating a thickness gradient in the stretchable conducting film. The first section at the outer circumference of the covering portion has greater thickness than the second section, providing localized reinforcement where stretchability changes are most pronounced, thereby preventing division while maintaining overall flexibility.
Solution Approach 2:
The patent uses a composite structure where the stretchable conducting film is formed with varying thickness, effectively creating a composite material system. The thicker first section acts as a reinforcement layer that combines with the thinner second section to achieve both stretchability and resistance to division.
Data Source
AI summary
A stretchable circuit board includes a stretchable substrate, a stretchable conducting film placed on one surface of the stretchable substrate and elongated in a first direction, an electric element placed on the one surface of the stretchable substrate, and a covering portion that covers a part of the stretchable conducting film and at least a part of the electric element, wherein, when an area of a first section as a section along an outer circumference of the covering portion in the stretchable conducting film is referred to as a first area and an area of a second section as a section of the stretchable conducting film orthogonal to the first direction in a location apart from the outer circumference of the covering portion toward outside is referred to as a second area, the first area is larger than the second area.