Flexible Microshield EMI Absorption Ferrite Metal Layers
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Solution Overview
Problem
Flexible circuits face challenges in impedance control and electromagnetic interference (EMI) suppression at high frequencies due to the limitations of traditional solid copper ground layers, which lead to signal distortion and reduced flexibility and density of components in compact electronic devices.
Innovation Solution
A multilayer absorber shield incorporating layers of indium tin oxide (ITO) and spinel nano ferrite powder with different compositions, providing broadband EMI suppression and impedance mismatch to absorb and attenuate EMI, while maintaining flexibility and compactness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If solid copper metal ground layer is used for impedance control, then impedance control is achieved, but flexibility decreases and thickness increases
Solution Approach 1:
The patent replaces solid copper metal ground layer with a thin film hatched ground pattern that maintains electrical functionality while providing flexibility. The hatched pattern consists of conductive traces arranged in a hatch configuration that provides impedance control without requiring thick solid metal layers, enabling the flexible circuit to bend and flex while maintaining electrical performance.
Solution Approach 2:
The solid copper ground layer is segmented into a hatched pattern of conductive traces. This segmentation divides the continuous metal layer into discrete traces arranged in a hatch configuration, which reduces the overall metal thickness and increases flexibility while maintaining impedance control through the distributed conductive structure.
2Manufacturing precision
If metal thickness is increased to provide impedance control, then impedance control improves, but flexibility decreases
Solution Approach 1:
The patent uses thin film hatched ground patterns instead of thick solid metal layers to achieve impedance control. The thin film structure with hatch configuration provides the necessary electrical performance for impedance control while maintaining the flexibility required for bendable flexible circuits.
3Ease of operation
If hatched ground shield is used to reduce thickness, then flexibility improves, but EMI protection decreases due to openings
Solution Approach 1:
The patent introduces a dielectric layer as an intermediary between the hatched ground pattern and the signal traces. This dielectric layer with appropriate permittivity and thickness compensates for the EMI protection reduction caused by the hatch openings, maintaining electrical performance and impedance control while preserving the flexibility benefits of the hatched configuration.
4Productivity
If multiple flexible circuits are stacked to increase density, then device compactness improves, but EMI interference between circuits increases
Solution Approach 1:
The patent employs thin film hatched ground patterns on each flexible circuit that provide EMI shielding while maintaining flexibility. When multiple flexible circuits are stacked, these hatched ground patterns act as EMI barriers between adjacent circuits, reducing electromagnetic interference while allowing high-density stacking to achieve compact device design.
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 multilayer shield effectively attenuates EMI across a wide frequency range, preventing signal distortion and allowing for compact, flexible electronic device designs without sacrificing impedance control or increasing thickness, thus enhancing the performance and integration of electronic components.
Implementation Method 1
The second metal layer includes ferrite powder. The ferrite powder is configured to absorb at least some of the reflected EMR energy and convert the absorbed EMR energy into thermal energy
Implementation Method 2
The first metal and the second metal are configured to reflect a first amount of the EMR energy transmitted through the first metal layer
Data Source
AI summary
A multilayer shield is used as an absorber for attenuating electromagnetic radiation (e.g., EMI) includes both metal and ferrite powder layers. Radiation transmitted through one of the metal layers be transmitted to an additional metal layer, and the radiation can be reflected between the metal layers. While reflected by the metal layers, the radiation is absorbed by one of the ferrite powder layers positioned between the metal layers, causing the ferrite powder layer to convert the radiation to thermal energy. Based on energy losses of the radiation due to reflection and thermal energy conversion, the radiation is sufficiently attenuated to limit disruption of nearby transmission signals, including high frequency transmission signals.