Laminate Wiring Sheet Structure for Thermal Expansion Mismatch
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Solution Overview
Problem
The existing wiring sheets, when used between base materials with different coefficients of linear expansion, can cause cracking due to thermal expansion differences.
Innovation Solution
A laminate structure comprising a first base material with a lower thermal expansion coefficient, a second base material with a higher thermal expansion coefficient, and a wiring sheet with a specific resin layer configuration to mitigate thermal stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a wiring sheet with a cured substance layer is used between base materials with different coefficients of linear expansion, then the resistance value of the wiring is stabilized, but one of the base materials may be cracked due to thermal expansion differences
Solution Approach 1:
The patent introduces a resin layer with specific mechanical properties (storage modulus between 1.0×10^4 to 1.0×10^6 Pa at 23°C) as an intermediary between the wiring sheet and the base materials. This intermediary layer absorbs thermal expansion differences through controlled deformation, preventing stress transmission that would cause cracking in the base materials while maintaining electrical connection stability.
Solution Approach 2:
The patent controls the storage modulus parameter of the resin layer within a specific range (1.0×10^4 to 1.0×10^6 Pa) to optimize its ability to deform under thermal stress. By adjusting this mechanical parameter, the resin layer can accommodate differential thermal expansion between base materials with different coefficients of linear expansion, preventing cracks while maintaining wiring stability.
2Reliability
If the wiring sheet directly contacts the base materials, then electrical connection is maintained, but thermal expansion differences cause cracking in the base materials
Solution Approach 1:
The resin layer serves as a mediator between the wiring sheet and base materials, providing both mechanical compliance to absorb thermal stress and electrical insulation to maintain connection stability. This intermediary structure eliminates direct contact between the rigid wiring sheet and base materials, preventing stress concentration while ensuring reliable electrical connection through the compliant resin medium.
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
Prevents cracking in the base materials by allowing the second resin layer to deform and absorb thermal expansion differences, maintaining structural integrity.
Implementation Method 1
one of the base materials may be cracked due to thermal expansion differences
Implementation Method 2
allowing the second resin layer to deform and absorb thermal expansion differences
Data Source
Figure 1
Figure 2~3
AI summary
A laminate (100) includes: a first base material (1); a second base material (2) having a higher linear coefficient of thermal expansion than the first base material (1); and a wiring sheet (10) held between the first base material (1) and the second base material (2), in which the wiring sheet (10) includes a wiring body (3) including a plurality of electrically conductive linear bodies (31) arranged with a spacing, a first resin layer (4) directly or indirectly supporting the wiring body (3), and a pair of electrodes (5) being in direct contact with the electrically conductive linear bodies (31), and the first base material (1) or the second base material (2) is laminated on the wiring sheet (10) via a second resin layer (6) having a lower storage modulus than the first resin layer (4).