Capacitive Touch Sensor Hard Press Rejection via Signal Slope Analysis
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional touch-input devices face challenges in accurately detecting and rejecting non-conductive objects and contacts through leather or plastic covers, leading to false contacts and poor user experience due to computationally intensive processing.
Innovation Solution
Implementing filter logic that analyzes the shape of the signal detected on a sensor array, computing a slope value based on signal distribution and area size, and rejecting signals indicative of hard press events, thereby distinguishing between intended and unintended contacts without relying on pressure signal values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional detection and rejection mechanisms are used to detect non-conductive objects and contacts through covers, then detection capability is improved, but computational complexity increases and user experience deteriorates
Solution Approach 1:
The patent segments the detection process into distinct phases: initial contact detection, hard press determination through slope analysis, and selective rejection. By dividing the computationally intensive detection into manageable segments with early exit conditions, the system achieves high detection precision without requiring full computational processing for every contact scenario.
Solution Approach 2:
The patent performs preliminary analysis by computing slope values from signal distributions before committing to full contact processing. This preliminary action allows the system to identify and reject hard press events early in the detection sequence, avoiding unnecessary computational overhead while maintaining accurate detection of valid contacts.
2Reliability
If computationally intensive processing is used to reject hard press events, then false contact detection is improved, but processing time increases and productivity decreases
Solution Approach 1:
The patent applies local quality analysis by examining the slope characteristics of signal distributions in specific regions of the sensor array. Instead of processing all contacts with uniform computational intensity, the system applies targeted slope analysis only where hard press events are suspected, achieving high reliability in false contact detection while maintaining fast processing for normal contacts.
Solution Approach 2:
The patent changes the parameter being analyzed from raw signal values to slope values derived from signal distributions. This parameter transformation enables the system to distinguish hard press events from normal contacts more efficiently, improving false contact detection reliability while reducing the computational resources required for processing.
3Measurement precision
If pressure signal values are used to detect hard press events, then detection accuracy is improved, but system complexity increases
Solution Approach 1:
The patent substitutes mechanical pressure sensing with an electrical field-based slope analysis approach. By analyzing the slope of signal distributions in the capacitive sensor array, the system can identify hard press events without requiring additional mechanical pressure sensors or complex pressure measurement mechanisms, thereby maintaining detection accuracy while reducing system 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
This approach effectively reduces false contact detection, enhancing user experience by accurately differentiating between normal and hard press contacts, thus improving the functionality and reliability of touch-input devices.
Implementation Method 1
Capacitive sensing typically involves scan operations that periodically measure changes in capacitance associated with the sensor elements to determine a presence, position, and/or movement of an object
Data Source
AI summary
Techniques for hard press rejection are described herein. In an example embodiment, a touch area on a sensor array is determined, where the touch area corresponds to a detected object and is associated with multiple signal values. A slope value for the detected object is computed based on a ratio of a signal distribution value in the touch area to a metric indicating a size of the touch area with respect to the sensor array. The slope value is compared to a threshold in order to determine whether to accept or to reject the detected object, and the detected object is rejected based on the comparison.