Knitted Fabric Touch Sensor With Two-Connection Pressure Sensing
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Solution Overview
Problem
Existing soft flexible touch sensors face challenges with manufacturability and robustness due to hard and fragile electronic components, complex production processes, and the need for multiple sensing electrodes, which limits their scalability and durability, especially in wearable and medical applications.
Innovation Solution
A fully knitted planar touch sensor with a three-layer structure comprising a nonconductive layer, a spacer fabric layer, and a conductive sensing element layer, using carbon fiber yarn to detect touch location and pressure with only two electrode connections, allowing for flexible and resilient designs that conform to arbitrary surfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If discrete sensing electrodes (wires) are used to form a sensing mesh, then touch sensing capability is achieved, but the number of required connections increases, reducing scalability
Solution Approach 1:
The patent merges multiple discrete sensing electrodes into a single continuous conductive knitted layer. The conductive yarn is knitted directly into the fabric structure, creating an integrated sensing element that eliminates the need for separate discrete electrodes and their associated connections, thus reducing wiring complexity while maintaining touch sensing capability
Solution Approach 2:
The conductive knitted layer serves multiple functions simultaneously: it acts as both the structural fabric and the sensing electrode. This multi-functional design eliminates the need for separate electrode components and connections, achieving touch sensing with minimal wiring while maintaining fabric flexibility and wearability
2Measurement precision
If hard and fragile embedded electronic components are used, then sensing functionality is achieved, but manufacturability and robustness are reduced
Solution Approach 1:
The patent changes the physical state and properties of the sensing material from hard and fragile electronic components to soft and flexible conductive yarn. The conductive yarn is knitted directly into the fabric using standard knitting machinery, transforming the sensing element into a wearable textile form that is both manufacturable and robust
Solution Approach 2:
The patent replaces traditional electronic sensing components with a mechanically integrated knitted structure. The conductive yarn is woven into the fabric using mechanical knitting processes, eliminating the need for separate electronic component assembly and improving both manufacturability and durability
3Measurement precision
If a dense weaving of conductive yarn in an XY grid pattern is used, then touch sensing is achieved, but the production process becomes lengthy and complex
Solution Approach 1:
The patent segments the sensing function from the structural fabric by using a single continuous conductive knitted layer instead of a dense XY grid pattern. This segmentation allows the sensing element to be produced more efficiently while maintaining touch sensing capability across the fabric surface
Solution Approach 2:
The patent uses a dynamic knitting process that can adapt the conductive yarn placement during manufacturing. The knitting machine can vary the pattern and density of conductive yarn incorporation, allowing for efficient production of sensing fabrics with different characteristics as needed
4Measurement precision
If multiple sensing electrodes are used, then sensing accuracy is improved, but wiring complexity increases, limiting scalability
Solution Approach 1:
The patent combines multiple sensing electrode functions into a single continuous conductive knitted layer. This integrated structure maintains the ability to detect touch across multiple points while eliminating the need for separate wiring for each sensing point, thus preserving sensing accuracy while reducing wiring complexity
Solution Approach 2:
The conductive knitted layer performs multiple sensing functions simultaneously across the entire fabric surface. This universal sensing capability allows the single-layer structure to replace multiple discrete electrodes, maintaining comprehensive touch detection while simplifying the wiring architecture
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 enables robust and scalable touch sensing with reduced wiring complexity, improved durability, and flexibility, suitable for various applications including smart garments, robotics, and medical textiles, while maintaining sensitivity and accuracy in detecting human touch and pressure.
Implementation Method 1
A fully knitted planar touch sensor with a three-layer structure comprising a nonconductive layer, a spacer fabric layer, and a conductive sensing element layer, using carbon fiber yarn to detect touch location and pressure
Data Source
AI summary
A planar (two-dimensional, XY location) touch sensor may include a knitted structure and supplementary method of sensing detects human touch on a fabric surface. This sensor may be fully knitted and detect the continuous planar location and contact force of human touch along the surface of the structure. The fabric may conform to any arbitrary surface and may be a rectangle for touch pad applications. This sensor may be used for applications that include robotics and human-machine interaction, smart garments and wearables, as well as medical textiles and flexible embedded sensors. This touch sensor may require as few as only two electrode connections from the fabric to sense both planar touch and pressure, which allows it to work in areas with limited space that allow for limited complexity for wiring.