Textile Fabric Capacitive Grid for Finger Touch Differentiation
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Solution Overview
Problem
Existing capacitive sensors for human skin struggle to differentiate finger touches due to parasitic capacitance coupling, making them ineffective for wearable applications.
Innovation Solution
A textile fabric with a capacitive grid design, featuring electrically conductive yarns isolated by insulating yarns and non-isolated conductive yarns forming an electrical grounding grid, which dampens parasitic capacitance and allows for detectable finger touches.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If capacitive sensors are implemented on human skin, then touch detection capability is provided, but parasitic capacitance coupling prevents effective differentiation of finger touches
Solution Approach 1:
The patent introduces an intermediary shielding layer composed of conductive yarns woven into the textile fabric. This shielding layer acts as a mediator between the capacitive sensor and the human skin, blocking parasitic capacitance coupling while allowing the sensor to detect finger touches. The conductive yarns create a capacitive grid that prevents direct capacitive coupling between the sensor and body, thereby enabling precise touch differentiation.
Solution Approach 2:
The patent employs composite material structure by integrating conductive yarns with insulating textile fibers to create a multi-functional fabric. The conductive yarns provide shielding and capacitive sensing functionality, while the insulating fibers maintain textile properties. This composite approach allows the fabric to simultaneously achieve parasitic capacitance damping and touch detection precision.
2Adaptability or versatility
If conductive electrodes are added to textile fabric for sensing, then capacitive sensing function is achieved, but essential garment features like breathability and stretchability are compromised
Solution Approach 1:
The patent uses thin conductive yarns woven into the textile fabric structure, creating a flexible capacitive grid that conforms to the fabric's mechanical properties. The conductive yarns are integrated at the yarn level rather than as separate rigid electrodes, allowing the fabric to maintain its inherent stretchability and breathability while providing capacitive sensing functionality.
Solution Approach 2:
The textile fabric serves multiple functions simultaneously: it provides mechanical protection, thermal regulation through breathability, and capacitive sensing through the integrated conductive yarns. The shielding layer and sensing elements are combined in a single multi-functional fabric structure, eliminating the need for separate sensing components that would compromise garment properties.
3Adaptability or versatility
If separate sensor parts are attached to garments, then sensing functionality is provided, but the sensors are not stretchable and lack moisture management features
Solution Approach 1:
The patent merges the sensing functionality with the garment fabric itself by weaving conductive yarns directly into the textile structure. This integration eliminates the need for separate sensor attachments, allowing the fabric to stretch and move with the body while maintaining sensing capability. The conductive yarns are incorporated during the fabric manufacturing process, ensuring consistent electrical properties and mechanical integration.
Solution Approach 2:
The textile fabric provides its own sensing functionality through the integrated conductive yarns, eliminating the need for external sensor components. The fabric structure itself serves as the sensing element, with the conductive yarns forming capacitive grids that detect touch and movement. This self-service approach ensures the sensor moves and stretches with the fabric without requiring separate flexible circuit boards or adhesive attachments.
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 textile fabric effectively dampens parasitic capacitance, enabling improved detection of finger touches and allowing for multi-directional swipe-sensitive capacitive sensing while maintaining essential garment features like breathability and stretchability.
Implementation Method 1
parasitic capacitance of the portion of human skin on which the textile is worn
Implementation Method 2
form an electrical grounding grid with the non-isolated conductive yarns of the second set of yarns
Implementation Method 3
an external object which parasitically couples its capacitance to the capacitance of the yarns
Data Source
AI summary
It is disclosed a textile fabric comprising a first set of electrically conductive and externally isolated yarns (22) separated by isolating textile yarns (24); a second set of non-isolated conductive yarns (23); a plurality of textile yarns interlacing the first and the second set of yarns (22, 23), wherein part of the interlacing textile yarns are non-isolated conductive yarns (23) in order to form an electrical grounding grid with the non-isolated conductive yarns (23) of the second set of yarns and part of the interlacing textile yarns are isolating textile yarns (24).