False Touch Detection for Capacitive Displays
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Solution Overview
Problem
Touch-sensitive systems struggle to differentiate between valid touches and false touches caused by water, leading to improper reporting of touch locations on the screen.
Innovation Solution
The system performs multiple scans of the touch-sensitive array over a time window, captures response data, and evaluates changes to identify chaotic behavior indicative of water contact by determining metrics based on peak characteristics, such as magnitude and variance, to reject false touch data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the touch-sensitive system uses capacitance sensing to detect touches, then it can detect user interactions, but water contact causes false touch readings
Solution Approach 1:
The system performs multiple preliminary scans of the touch-sensitive array before finalizing touch detection. By capturing response data across multiple scans and evaluating changes over time, the system can identify and reject false touches caused by water before they are reported as valid user interactions.
Solution Approach 2:
The system uses feedback from multiple sequential scans to evaluate response data patterns. By comparing response data across scans and identifying chaotic behavior that deviates from normal touch patterns, the system can distinguish water contact from valid touches and adjust its detection accordingly.
2Reliability
If the system performs multiple scans over time to differentiate valid touches from false touches, then false touch detection improves, but processing time and complexity increase
Solution Approach 1:
The system performs a predetermined number of scans that may be more than the minimum needed for single-touch detection. By capturing response data across multiple scans and evaluating changes over time, the system ensures reliable differentiation between valid touches and false touches caused by water or other contaminants.
Solution Approach 2:
The system uses its own existing scan infrastructure and response data to perform false touch detection, rather than requiring separate sensors or external systems. By evaluating changes in response data across multiple scans using the same sensor array, the system achieves improved reliability without adding significant hardware complexity.
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
Effectively differentiates between valid and false touches by accurately identifying chaotic patterns caused by water, reducing false touch reporting and improving user interaction reliability.
Implementation Method 1
A touch-sensitive system (e.g., capacitance sensing) may include a touch screen, touch-sensor pad, a touch-sensor slider, or touch-sensor buttons, and may include an array of one or more sensor elements. Touch sensing typically involves measuring, through sensor signals (e.g., increases or decreases in electrode responses), a change in capacitance associated with the sensor elements to determine a presence of an object relative to the sensor elements.
Data Source
AI summary
The various implementations described herein include systems, methods and/or devices used to enable false touch detection. An exemplary method is performed at a touch-sensitive device and includes performing a plurality of scans of the touch-sensitive array during a time window, response data is captured from each of the plurality of scans. Distilling a value for each respective scan from the response data captured during the respective scan. Identifying a set of peaks from the distilled values, each peak having a plurality of characteristic values. The method further includes: (i) determining a metric for the peaks based on the plurality of characteristic values associated with each peak; (ii) determining whether the metric satisfies a criterion, and (iii) in response to determining that the metric satisfies the criterion, rejecting at least some of the response data captured during the time window as representing at least one false touch.