Stretchable Liquid Metal Conductors for Dental Applications
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Solution Overview
Problem
Current stretchable electronics face limitations in elongation ability, conductivity, transition performance between substrates, bulky architecture, inclusion of harmful materials, and high electrical resistance, which restrict their application in fields like dentistry where minimal thickness and safety are crucial.
Innovation Solution
A method involving continuous deposition of liquid metal with adhesion and conductive metals by evaporation onto stretchable substrates, allowing for deformation beyond 300% elongation while maintaining conductivity, eliminating the need for interface materials and resulting in a very thin circuit board.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If thin film metal deposition is used to create stretchable electrical connections, then the connections remain conductive during elastic deformation up to 20-25% elongation, but the connections become non-conductive at elongations larger than 20-25%
Solution Approach 1:
The patent changes the physical state of the conductive material from solid thin film metal to liquid metal, allowing the connections to deform continuously with the substrate without fracturing. The liquid metal's ability to flow and reconfigure enables elongation beyond 20-25% while maintaining conductivity, directly resolving the contradiction between reliability during deformation and adaptability to larger elongations.
2Object-affected harmful factors
If conductive pastes or liquid metal alloys are added at the interface to reduce friction, then rubbing and shearing are reduced, but the mechanical performance of the transition is poor and limits elongation to 5-10%
Solution Approach 1:
The patent extracts and eliminates the interface transition layer (conductive pastes or liquid metal alloys) that causes friction and limits elongation. By directly depositing liquid metal onto the elastic substrate without intermediate materials, the harmful friction and shearing are removed, and the elongation limit of 5-10% is overcome, achieving elongation beyond 20-25% while maintaining low friction.
3Adaptability or versatility
If liquid metal or conductive pastes are used to create stretchable patterns, then the elastic deformation range is increased to 80-150% elongation, but the conductivity of the electrical connection is lower
Solution Approach 1:
The patent optimizes the composition and physical parameters of the liquid metal, using eutectic gallium-indium alloy with specific properties that balance conductivity and deformability. By controlling deposition parameters and liquid metal composition, the patent achieves both high elasticity (80-150% elongation) and high conductivity, resolving the contradiction between adaptability and reliability.
4Object-affected harmful factors
If conductive pastes or gels are used to reduce rubbing at the interface, then mechanical contact is improved, but these materials are harmful for humans and require bulky encapsulation
Solution Approach 1:
The patent extracts and removes harmful conductive pastes or gels from the system, replacing them with non-toxic liquid metal (eutectic gallium-indium alloy) that can be directly deposited on the substrate. This eliminates the need for bulky encapsulation while maintaining low friction and shearing, simultaneously resolving both the toxicity and bulkiness issues.
5Volume of moving object
If traditional metallization processes are used, then the circuit board thickness is very thin, but the transition to traditional electronic substrates is poor and limits elongation
Solution Approach 1:
The patent changes the deposition process parameters and material state, using liquid metal deposition instead of traditional solid film metallization. This enables the creation of ultra-thin conductive layers that maintain flexibility and compatibility with traditional electronic substrates, achieving both thin thickness and good transition performance with high elongation capability.
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 method enables stretchable conductors and connections that remain conductive beyond 300% elongation, reduce bulkiness, and eliminate harmful materials, enhancing mechanical and electrical performance for applications like dental occlusion assessment and implantable electrodes.
Implementation Method 1
the liquid metal, the conductive metal and the adhesion material are deposited by evaporation, the deposition being made in vacuum
Implementation Method 2
depositing the liquid metal; depositing the adhesion material; and depositing the conductive metal; the liquid metal, the conductive metal and the adhesion material are deposited by evaporation
Data Source
Figure 1A~2B
Figure 3~4
Figure 5(a)~6B
AI summary
The present invention relates to a method for producing a stretchable conductor and/or electrical connection comprising - providing a stretchable substrate, a liquid metal, a conductive metal and an adhesion material in a same evaporator chamber; - depositing the liquid metal; - depositing the adhesion material; - depositing the conductive metal; wherein - the liquid metal, the conductive metal and the adhesion material are deposited by evaporation; and - the deposition by evaporation is made in vacuum.