Flexible Circuit Board With Liquid Metal Shielding for High-Frequency Bending
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Solution Overview
Problem
Conventional circuit boards face challenges in achieving high frequency signal transmission and sufficient bending flexibility due to limitations in shielding layers, which lead to radiation, crosstalk, and potential cracking during bending.
Innovation Solution
A flexible circuit board design that embeds a signal layer within dielectric layers and surrounds the trace with liquid metal composites, using cellulose nanofiber and liquid metal as a stable composite, providing electromagnetic shielding and flexibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional shielding layers are used for high frequency signal transmission, then electromagnetic shielding is improved, but bending flexibility deteriorates due to potential cracking
Solution Approach 1:
The patent changes the physical state of the shielding material from solid (conventional metal shields) to liquid (liquid metal composites). This parameter change allows the shielding layer to conform to bending deformations without cracking, while maintaining electromagnetic shielding effectiveness through the conductive liquid metal particles suspended in a flexible matrix.
Solution Approach 2:
The patent uses composite materials by combining liquid metal particles with a flexible polymer matrix to create liquid metal composites. This composite structure provides both the electromagnetic shielding properties of metal and the flexibility of the polymer, resolving the contradiction between shielding effectiveness and bending flexibility.
2Ease of operation
If signal layer is exposed for component connection, then ease of operation is improved, but signal integrity deteriorates due to radiation and crosstalk
Solution Approach 1:
The patent embeds the signal layer within the dielectric layer, creating a nested structure where the signal trace is surrounded and protected by the dielectric material. This nesting provides electromagnetic shielding for the signal while still allowing component pads to be accessible on the surface for connections, thus maintaining both signal integrity and ease of operation.
3Volume of moving object
If circuit board is thinned for miniaturization, then productivity is improved, but bending property deteriorates
Solution Approach 1:
The patent employs flexible dielectric layers and liquid metal composite shielding layers that maintain flexibility even in thin configurations. These flexible layers prevent cracking during bending operations, allowing the circuit board to be thinned for miniaturization while preserving adequate bending properties through the inherent flexibility of the material composition.
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 design achieves high frequency signal transmission and supports dynamic bending without cracking, while allowing direct electrical connection of components to the signal layer, enhancing miniaturization and signal integrity.
Implementation Method 1
uses a liquid metal surrounding a trace of the signal layer to require demand for bending and high frequency signal transmission
Data Source
AI summary
A flexible circuit board and a method of fabricating the same are provided. The flexible circuit board includes a first dielectric layer, a second dielectric layer disposed on the first dielectric layer, a signal layer disposed within the second dielectric layer, a third dielectric layer disposed on the second dielectric layer, and liquid metal composites. The signal layer includes a trace and a pad. The liquid metal composites are disposed to surround the trace, but not enclose the pad, thereby satisfying requirements of the signal layer for great bending numbers and high frequency signal transmission.