Adaptive Touch Sensor Thresholding for Grounding Variations
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Solution Overview
Problem
Touch sensors face challenges in accurately detecting touches across various grounding scenarios due to fixed detection thresholds, which can lead to false negatives in floating environments and false positives in grounded environments.
Innovation Solution
Implementing an adaptive touch detection thresholding system that adjusts based on the device's grounding scenario by measuring changes in capacitance and calculating new threshold values based on the strength of the charge return path, allowing for improved touch detection in both floating and grounded conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a fixed touch detection threshold is used, then the device complexity is reduced, but the reliability of touch detection deteriorates in varying grounding scenarios
Solution Approach 1:
The patent implements dynamic threshold adjustment by continuously monitoring capacitance values and automatically adapting the touch detection threshold based on the current grounding scenario. Instead of using a fixed threshold, the system dynamically modifies the threshold value to match the environmental conditions, thereby maintaining high touch detection reliability across varying scenarios without requiring complex manual configuration
Solution Approach 2:
The system employs feedback mechanisms by monitoring the capacitance values from the touch sensor and using this information to adjust the detection threshold. The controller continuously receives feedback from the sensor about the current electrical environment and automatically adapts the threshold accordingly, creating a closed-loop system that maintains optimal detection accuracy without user intervention
2Object-generated harmful factors
If a low detection threshold is used, then false positives are reduced in grounded environments, but false negatives increase in floating environments
Solution Approach 1:
The patent changes the detection threshold parameter dynamically based on the grounding scenario. In grounded environments, the system adjusts the threshold to a lower value to filter out noise and prevent false positives. In floating environments, it raises the threshold to maintain sensitivity and avoid false negatives. This parameter adaptation allows the system to optimize performance for different electrical conditions
3Object-generated harmful factors
If a high detection threshold is used, then false positives are reduced in floating environments, but false negatives increase in grounded environments
Solution Approach 1:
The system adjusts the detection threshold parameter to a higher value when operating in floating environments to prevent false positives caused by electrical noise. Conversely, in grounded environments, it lowers the threshold to maintain sensitivity and prevent false negatives. This dynamic parameter adjustment ensures optimal detection accuracy across different grounding scenarios
4Reliability
If adaptive threshold adjustment is implemented, then touch detection reliability is improved, but device complexity increases
Solution Approach 1:
The system implements self-service by automatically monitoring its own operating conditions and adjusting the detection threshold without external intervention. The controller autonomously determines the grounding scenario based on capacitance measurements and independently modifies the threshold parameter, eliminating the need for manual configuration or complex external control mechanisms while maintaining high detection reliability
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
Enhances touch detection accuracy by dynamically adjusting the detection threshold, ensuring reliable interaction in all grounding scenarios, reducing false positives and negatives.
Implementation Method 1
When an object touches or comes within proximity of the surface of the capacitive touch screen, a change in capacitance occurs within the touch screen at the location of the touch or proximity.
Implementation Method 2
measuring changes in capacitance and calculating new threshold values based on the strength of the charge return path
Data Source
AI summary
In one embodiment, a method includes receiving, by a controller coupled to a touch sensor, a plurality of signals from a plurality of sense electrodes, the plurality of signals indicative of an amount of capacitance between the touch sensor and an external object. The method further includes accessing a stored threshold value, determining a strength of a charge return path between the touch sensor and a ground, and adjusting the stored threshold value based on the determined strength of the charge return path. The threshold value indicates a threshold magnitude of the signals from the plurality of sense electrodes to process as a touch by the external object.