Liquid Metal Interconnects for Flexible Electronic Assemblies
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Solution Overview
Problem
Existing methods for electrically and mechanically mounting rigid electronic components to flexible components in chip-on-flex assemblies often result in reduced flexibility and durability due to the use of rigid materials, leading to potential failure under deforming stresses and repeated movements.
Innovation Solution
The use of flexible interconnects, such as liquid metal or conductive polymers, bridging between conductive traces and pads on a flexible substrate, with an encapsulant to maintain electrical connections and distribute stress, allowing for self-healing and improved flexibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If rigid materials are used to mount electronic components to flexible substrates, then mechanical strength is improved, but flexibility and durability under deforming stresses deteriorate
Solution Approach 1:
The patent changes the physical state of the interconnect material from solid (rigid) to liquid (flexible). The liquid metal interconnect maintains electrical conductivity while adapting to substrate deformation, resolving the contradiction between mechanical strength and flexibility by transforming the material parameter from rigid to liquid state.
Solution Approach 2:
The patent uses a composite structure combining liquid metal interconnect with encapsulant material. The liquid metal provides electrical conductivity and flexibility, while the encapsulant provides mechanical protection and structural support, creating a composite system that achieves both strength and flexibility.
2Stability of the object's composition
If rigid interconnects are used, then electrical connection stability is improved, but reliability under repeated movements and deforming stresses deteriorates
Solution Approach 1:
The patent employs a dynamic interconnect solution using liquid metal that can continuously adapt its shape and position in response to substrate deformation. Unlike rigid interconnects that fail under stress, the liquid metal flows and reconfigures to maintain electrical connection, providing dynamic reliability under repeated movements and deformations.
Solution Approach 2:
The liquid metal interconnect exhibits self-healing properties, automatically restoring broken electrical pathways through capillary action and surface tension without external intervention. This self-service capability ensures continuous reliability even after mechanical stress or minor disruptions.
3Adaptability or versatility
If liquid metal interconnects are used, then flexibility and self-healing properties are improved, but protection from oxidation and environmental damage worsens
Solution Approach 1:
The patent introduces encapsulant material as an intermediary barrier between the liquid metal interconnect and the external environment. This encapsulant layer prevents direct contact with oxygen and moisture, protecting the liquid metal from oxidation and environmental damage while allowing the interconnect to maintain its flexibility and electrical conductivity.
Solution Approach 2:
The encapsulant creates an inert protective environment around the liquid metal interconnect, isolating it from reactive atmospheric components. This inert barrier prevents oxidation and chemical degradation, allowing the liquid metal to maintain its protective oxide layer and electrical properties over time.
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
Enhances the flexibility and durability of the assembly by maintaining electrical connections and preventing breakages under stress, while providing self-healing properties to the interconnects.
Implementation Method 1
a liquid metal interconnect bridging between a pad on the component and the trace on the flexible substrate
Implementation Method 2
an encapsulant covering the interconnect
Data Source
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AI summary
Examples are disclosed that relate to flexible electrical interconnects in electronic devices. One example provides a device including a flexible substrate, a conductive trace disposed on the flexible substrate, an electronic component mounted to the flexible substrate, a liquid metal interconnect bridging between a pad on the component and the trace on the flexible substrate, and an encapsulant covering the interconnect.