Capacitive Touch Threshold Adjustment for Noise-Robust Detection
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Solution Overview
Problem
Existing touch detecting apparatuses face challenges in accurately detecting touches in environments with varying noise levels, particularly due to fluctuations in capacitance noise.
Innovation Solution
A touch detecting apparatus equipped with an electrostatic sensor and a touch detecting unit that adjusts a touch threshold by adding a correction value when noise exceeds a predetermined threshold, ensuring accurate detection by considering noise variations over time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a fixed touch threshold is used for detection, then the device structure remains simple, but detection accuracy deteriorates in environments with varying noise levels
Solution Approach 1:
The touch threshold is transformed from a fixed value to a dynamic value that automatically adjusts based on measured noise levels. The control unit continuously monitors capacitance changes, calculates noise thresholds, and modifies the touch detection threshold accordingly, enabling the system to adapt to varying environmental conditions without manual intervention.
Solution Approach 2:
A feedback loop is established where the control unit measures capacitance changes, compares them against the touch threshold, detects noise levels, and adjusts the threshold based on the measured noise. This closed-loop system continuously optimizes detection accuracy by using past detection results to inform future threshold settings.
2Measurement precision
If the touch threshold is lowered to detect lighter touches, then detection sensitivity improves, but false positives increase due to noise
Solution Approach 1:
The system dynamically changes the touch threshold parameter based on measured noise levels. When noise is detected, the threshold is raised to prevent false positives; when noise is low, the threshold is lowered to improve sensitivity. This adaptive parameter adjustment allows the system to optimize between sensitivity and reliability based on current environmental conditions.
Solution Approach 2:
The touch threshold transitions from a static value to a dynamic value that responds to real-time noise measurements. The control unit continuously adjusts the threshold level based on the calculated noise threshold, enabling the system to maintain optimal detection performance across varying conditions without manual recalibration.
3Reliability
If noise filtering is applied to reduce false detections, then reliability improves, but response time increases due to additional processing
Solution Approach 1:
The system performs preliminary noise measurement and threshold calculation in advance, storing the results for quick retrieval during touch detection. By pre-processing the noise characterization and having the threshold adjustment mechanism ready, the system minimizes the time penalty associated with noise filtering while maintaining high detection accuracy.
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 apparatus effectively detects touches with high accuracy even in noisy environments by dynamically adjusting the touch threshold, reducing false positives and negatives.
Implementation Method 1
an electrostatic sensor 110 that is provided for the grip 11; and a touch detecting unit 122 that detects whether a hand H touches the grip 11 based on a capacitance measured by the electrostatic sensor 110
Data Source
AI summary
A touch detecting apparatus includes an electrostatic sensor provided on an object; and a processor configured to detect whether a hand touches the object based on a capacitance measured by the electrostatic sensor. The processor is configured to, in response to the capacitance being greater than or equal to a first touch threshold, detect that the hand touches the object, and, for a second predetermined time from when a change amount of the capacitance during a first predetermined time becomes greater than or equal to a noise threshold, continue a state where a correction value has been added to the first touch threshold.