Fabric Touch Sensing Drift Correction via Reference Nodes
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Solution Overview
Problem
Fabric touch-sensitive layers in electronic devices are prone to drift due to moisture, liquids, or chemicals absorption, leading to inaccurate touch and proximity sensing, which can result in uneven detection and false gestures.
Innovation Solution
Incorporating reference nodes within the fabric layer, isolated from external effects, to account for absorption-induced drift, allowing for recalibration of touch nodes based on measurements from these reference nodes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If fabric touch-sensitive layers are used to provide flexible and comfortable input surfaces, then ease of operation and adaptability are improved, but measurement precision deteriorates due to drift caused by moisture, liquids, or chemicals absorption
Solution Approach 1:
The patent introduces a reference layer as an intermediary component between the fabric touch-sensitive layer and the environment. This reference layer absorbs moisture, liquids, or chemicals at a controlled rate that matches the fabric layer, serving as a mediator that compensates for environmental effects. By measuring capacitance changes in the reference layer and using them to correct measurements from the fabric layer, the system maintains measurement precision while preserving the flexibility and comfort of fabric touch surfaces
Solution Approach 2:
The patent changes the physical-chemical parameters of the reference layer to match those of the fabric touch-sensitive layer, particularly the absorption characteristics. By selecting materials with similar moisture absorption rates and capacitance properties, the reference layer undergoes parameter changes (moisture content, dielectric constant) that mirror those of the fabric layer, enabling accurate compensation for environmental drift without affecting the fabric's operational properties
2Adaptability or versatility
If fabric layers are used for touch sensing, then adaptability and comfort are improved, but reliability deteriorates due to drift in measurements from absorption of moisture, liquids or chemicals
Solution Approach 1:
The patent implements a feedback mechanism where the capacitance measurements from the reference layer are continuously monitored and used to adjust or correct the measurements from the fabric touch-sensitive layer. The processing circuitry calculates the drift based on reference layer changes and applies compensation algorithms to maintain accurate touch detection. This closed-loop feedback system ensures reliable measurements even as the fabric layer absorbs moisture or chemicals over time
Solution Approach 2:
The patent performs preliminary calibration of the system by establishing baseline capacitance values for both the fabric layer and reference layer under controlled conditions. This preliminary action allows the system to pre-determine the absorption characteristics and drift patterns, which are then used to create correction factors before actual use. By preparing the compensation model in advance, the system maintains reliability without requiring real-time complex calculations
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
This approach effectively stabilizes touch and proximity sensing performance by adjusting touch node measurements, reducing false detections and improving accuracy even under varying environmental conditions.
Implementation Method 1
Fabric touch-sensitive layers provided for electronic devices can absorb moisture, liquids or chemicals, which can cause drift in measurements of touch nodes formed in the fabric layer
Implementation Method 2
A fabric touch-sensitive layer can include an array of capacitive touch nodes
Data Source
AI summary
Fabric touch-sensitive layers provided for electronic devices can absorb moisture, liquids or chemicals, which can cause drift in measurements of touch nodes formed in the fabric layer. In some examples, reference nodes formed in a fabric layer can be used to account for drift due to the absorption of moisture, liquids or chemicals. The reference nodes can be isolated from the effects of proximate or touching objects and from absorption of moisture, liquids or chemicals. The reference nodes can also be formed in a fabric layer having the same or similar properties as the fabric touch-sensitive layers. When measurements of touch nodes drift due to changes in absorption, the measurements can be adjusted based on measurements of reference nodes.