Alternating Conductivity Laminated Sheet for EM Shielding
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Solution Overview
Problem
Existing electromagnetic wave shielding materials face challenges in achieving high shielding properties while maintaining moldability and production efficiency, as they often require thick substrates or high concentrations of electrically conducting additives, leading to issues like uneven thickness and cracking during extrusion.
Innovation Solution
A multi-layer sheet with alternating layers of different conductivities, characterized by a peak return loss of 5 dB or more and a coefficient of variation in layer thickness of 0.3 or less, utilizing thermoplastic resins and controlled dielectric constants to enhance electromagnetic wave shielding properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the substrate thickness is increased or the concentration of electrically conducting additives is increased to achieve high electromagnetic wave shielding properties, then the shielding performance is improved, but the moldability deteriorates and production efficiency decreases due to uneven thickness and cracking during extrusion
Solution Approach 1:
The invention divides the shielding function into multiple layers with different conductivities rather than relying on a single thick substrate or high concentration of additives. The multi-layer structure segments the electromagnetic wave shielding task across interfaces, achieving high shielding performance without increasing overall thickness or additive concentration, thereby maintaining moldability and production efficiency.
Solution Approach 2:
The invention uses composite materials with different conductivities arranged in alternating layers. This composite structure leverages the dielectric polarization effect at interfaces between layers with different electrical properties, achieving enhanced electromagnetic wave shielding without requiring high concentrations of conducting additives or increased substrate thickness, thus resolving the contradiction between shielding performance and manufacturability.
2Reliability
If high concentrations of electrically conducting additives are used to achieve high shielding properties, then the shielding performance is improved, but the production stability deteriorates due to cracking during extrusion
Solution Approach 1:
The invention segments the conducting additives across multiple layers rather than concentrating them in a single substrate. Each layer contains a controlled amount of additives, and the interfaces between layers provide dielectric polarization effects that enhance shielding. This segmentation prevents the cracking issues associated with high concentrations of additives in a single layer while maintaining production stability.
Solution Approach 2:
The invention employs composite materials with controlled additive concentrations in each layer. The alternating structure of conductive and less conductive layers ensures that no single layer requires excessive additive concentration, thereby preventing cracking during extrusion and ensuring production stability while achieving high shielding performance through the collective effect of all layers.
3Reliability
If thick substrates are used to achieve high shielding properties, then the shielding performance is improved, but the production efficiency decreases due to uneven thickness during extrusion
Solution Approach 1:
The invention segments the shielding function across multiple thin layers rather than using a single thick substrate. Each layer can be extruded with controlled, uniform thickness, and the cumulative shielding effect is achieved through the interface dielectric polarization between layers. This approach maintains production efficiency by avoiding the thickness control difficulties associated with thick substrates while delivering high shielding performance.
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 multi-layer sheet achieves high electromagnetic wave shielding with improved moldability and production stability, even with reduced additive concentrations, by leveraging dielectric polarization at layer interfaces.
Implementation Method 1
by leveraging dielectric polarization at layer interfaces
Implementation Method 2
materials that reflect electromagnetic waves at the surface and inside of the materials
Implementation Method 3
absorb electromagnetic waves inside the materials, resulting in loss or attenuation of the energy of the electromagnetic waves
Data Source
Figure 1~2
Figure 3~4
AI summary
The present invention aims to provide a multi-layer sheet with excellent electromagnetic wave shielding properties. The multi-layer sheet includes an alternating multilayer unit with five or more A layer and B layer alternately laminated, in which the electromagnetic return loss at the peak top in the peak of return loss spectrum with the highest return loss at the peak top is 5 dB or more in a chart of the return loss in the multi-layer sheet.