Flexible Sensor Using Conductive Particle Matrix
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Solution Overview
Problem
Conventional silicon-based sensors are fragile and unable to adapt to complex curved surfaces, limiting their applications, while existing PVDF piezoelectric film sensors are complex to process, difficult to wire, and costly to manufacture.
Innovation Solution
A flexible sensor comprising a strain film with a flexible substrate, electrically conductive layers, and a signal amplifying circuit, featuring a Wheatstone bridge configuration and using carbon powder or metal powder, carbon fibers, nanometer carbon tubes, or graphene for high sensitivity and ease of wiring, with a simple processing technique and low manufacturing cost.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional silicon-based sensors are used, then measurement precision is achieved, but reliability deteriorates due to fragility and inability to endure large deformation
Solution Approach 1:
The patent changes the material parameter from rigid silicon to flexible conductive materials (carbon powder, metal powder, carbon fibers, nanometer carbon tubes, or graphene) dispersed in a polymer matrix. This parameter change enables the sensor to withstand large deformations and bending while maintaining sensing capability, thus improving reliability without sacrificing measurement precision.
Solution Approach 2:
The patent employs composite materials consisting of conductive particles/fibers embedded in a polymer matrix to create the flexible sensing layer. This composite structure combines the flexibility and deformability of the polymer with the electrical conductivity of the conductive materials, resolving the contradiction between durability under deformation and sensing accuracy.
2Reliability
If PVDF piezoelectric film sensors are used, then reliability and adaptability to curved surfaces are improved, but device complexity increases due to complex processing steps
Solution Approach 1:
The patent extracts and eliminates the complex multi-step processing procedures (silicon dioxide deposition, PDMS layer preparation, metal sputtering, etching, device transferring, wire bonding, surface reinforcing) from the PVDF sensor fabrication process. The invention achieves reliability and flexibility through a simplified structure of flexible substrate, conductive layers, and electrodes, removing unnecessary processing steps while maintaining sensor performance.
Solution Approach 2:
Instead of following the conventional complex PVDF fabrication process, the patent inverts the approach by using a simpler flexible substrate with dispersed conductive materials and basic electrode structures. This inverted methodology achieves the same reliability goals with dramatically reduced processing complexity.
3Adaptability or versatility
If PVDF piezoelectric film sensors are used, then adaptability to complex surfaces is improved, but manufacturing cost increases
Solution Approach 1:
The patent employs inexpensive conductive materials such as carbon powder, metal powder, carbon fibers, nanometer carbon tubes, or graphene dispersed in a polymer matrix, replacing costly PVDF piezoelectric films. These materials can be applied through simple coating or printing techniques, dramatically reducing manufacturing cost while maintaining flexibility and adaptability to complex surfaces.
Solution Approach 2:
The patent changes the material composition parameters from expensive PVDF piezoelectric film to cost-effective conductive particle-polymer composites. This parameter change enables flexible sensor fabrication using low-cost materials and simple processing methods, achieving adaptability to complex surfaces without increasing manufacturing cost.
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 flexible sensor offers high sensitivity, ease of wiring, and low manufacturing costs, enabling effective monitoring of human body health conditions such as heartbeat and breathing, replacing conventional PVDF piezoelectric film sensors with improved flexibility and durability.
Implementation Method 1
the electrically conductive layers, which cover upper and lower surfaces of the flexible substrate, respectively, include a matrix and first electrically conductive particles which are dispersed in the matrix
Data Source
AI summary
A flexible sensor used for touch detection and an application thereof. The flexible sensor having a flexible substrate, at least two conductive layers and a plurality of electrodes, the conductive layers respectively covering two surfaces of the flexible substrate, the electrodes being arranged at two ends of the conductive layers, the conductive layers having a matrix and first conductive particles dispersed within the matrix. The sensor has stable output characteristics and good consistency between individuals, is easy to install, low-cost and highly sensitive, and can replace PVDF piezoelectric thin film sensors for monitoring human heartbeat and breathing state data.