Graphene Ink Membrane Touch Switches for Flex and Moisture Resistance
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Solution Overview
Problem
Existing membrane touch switches (MTS) face issues such as circuit breakage, dielectric layer failures, abrasion damage, silver electromigration, gas and moisture ingress, and tail connector failures due to mechanical deformation, environmental stress, and moisture exposure, necessitating improved materials and substrates for enhanced robustness and operational life.
Innovation Solution
The use of graphene-carbon, graphene, metal, and dielectric inks, along with engineered polymer substrates, to create a multilayered structure that is flexible, mechanically robust, and resistant to abrasion and moisture, with a polymer binder system ensuring compatibility and adhesion, and UV or thermal curing methods for efficient manufacturing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional silver conducting materials are used in MTS circuits, then electrical conductivity is achieved, but the circuits exhibit breakage failure when subjected to mechanical deformation or bending
Solution Approach 1:
The patent uses composite conducting inks containing silver particles combined with flexible polymer matrices and graphene additives. This composite structure maintains electrical conductivity through the silver network while the polymer matrix and graphene provide mechanical flexibility and crack resistance, allowing the circuit to withstand repeated bending and deformation without breakage.
Solution Approach 2:
The patent modifies the physical and chemical parameters of conducting materials by using nanoscale silver particles instead of traditional bulk silver, and by adjusting the polymer matrix composition and crosslinking density. These parameter changes enable the conducting layer to maintain electrical performance while achieving the required mechanical flexibility and elasticity for flexible MTS applications.
2Reliability
If traditional carbon and dielectric inks are used to protect silver conductors, then electromigration protection is provided, but the protective layers fail to effectively block moisture ingress
Solution Approach 1:
The patent employs composite dielectric and carbon protective layers that integrate hydrophobic polymer matrices with graphene or carbon nanotube additives. This composite structure provides dual functionality: the carbon network protects against electromigration while the hydrophobic polymer matrix with low water permeability effectively blocks moisture ingress, solving both protection requirements simultaneously.
Solution Approach 2:
The patent uses fluorinated polymer matrices and crosslinking agents that create a chemically inert and hydrophobic environment around the silver conductors. This inert protective layer prevents moisture and oxygen from reaching the silver, thereby blocking both electromigration and corrosion pathways caused by moisture exposure.
3Ease of manufacture
If conventional polymer substrates are used for MTS fabrication, then manufacturing simplicity is maintained, but the devices lack sufficient flexibility and mechanical robustness
Solution Approach 1:
The patent uses composite polymer substrates that combine flexible polymers (such as polyimide or polyester) with reinforcing fibers, graphene, or nanocellulose additives. This composite structure maintains the ease of fabrication through conventional printing and curing processes while significantly enhancing mechanical robustness, flexibility, and tear resistance of the substrate.
Solution Approach 2:
The patent employs thin-film polymer substrates with optimized thickness and crosslinking to achieve the desired flexibility and mechanical strength. These flexible thin films are designed to bend and conform without cracking, providing the necessary mechanical robustness for flexible MTS applications while remaining compatible with standard manufacturing processes.
4Ease of operation
If repeated actuation of metal dome switches is performed, then switching function is achieved, but abrasion damage occurs to the protective carbon layers and silver layers
Solution Approach 1:
The patent uses composite protective layers combining hard carbon materials (such as diamond-like carbon or graphitic carbon) with flexible polymer binders. This composite structure provides high abrasion resistance to withstand repeated dome actuation while maintaining flexibility and adhesion to the underlying silver conductors, preventing delamination and wear damage.
Solution Approach 2:
The patent applies multiple layers of protective carbon and dielectric coatings before the MTS device is put into service. These pre-applied protective layers act as sacrificial cushioning that absorbs wear and abrasion during repeated actuation, protecting the underlying silver conductors and maintaining circuit integrity throughout the device's operational life.
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 solution enhances the operational life and reliability of MTS devices by providing superior flexibility, mechanical robustness, and environmental durability, while reducing manufacturing costs and time, and enabling complex, curved, or 3D conformed structures.
Implementation Method 1
UV or thermal curing methods for efficient manufacturing
Implementation Method 2
UV or thermal curing methods for efficient manufacturing
Data Source
AI summary
This invention discloses formulations of mutually compatible sets of graphene, graphene-carbon, metal and dielectric inks for the fabrication of high performance membrane touch switches (MTS). The compositions of these inks are optimized to achieve higher degree of compatibility with highly engineered polymeric substrates, thereby offering a holistic solution for fabricating high-performance MTS. These sets of materials can also be used for fabrication of sensors, biosensors and RFIDs on flexible substrates, such as polymers and papers.