Capacitance Hotspot Feature Detection for Odd-Form Touch Suppression
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Solution Overview
Problem
Capacitive touchscreens struggle to accurately differentiate between finger touches and accidental contacts from non-finger parts like ears or cheeks during calls, leading to misoperations due to delays and identification angle limitations in optical proximity sensors.
Innovation Solution
A report point output control method that performs feature detection on capacitance hotspots to determine eigenvalues such as horizontal span, eccentricity, and shadow lengths, distinguishing between normal finger taps and odd-form touches like cheeks or ears by processing capacitance features like shape, size, and time-varying trends.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If optical proximity sensor is used to identify obstacles, then screen-off function is activated to prevent accidental touches, but the sensor cannot identify obstacles in some scenarios due to identification angle limitations and there is a delay from identifying obstacle to screen-off
Solution Approach 1:
The system performs preliminary analysis on capacitance data to predict potential accidental touches before they occur. By analyzing the characteristics of capacitance changes in advance, the system can prepare for screen-off action proactively, reducing the actual response delay when an obstacle is detected.
Solution Approach 2:
The system dynamically adjusts the screen-off threshold based on real-time capacitance data characteristics. Instead of using a fixed threshold, the system adapts the sensitivity level according to the current touch pattern and capacitance variation rate, enabling faster and more accurate response to different touch scenarios.
2Reliability
If optical proximity sensor is used to identify obstacles, then screen-off function is activated to prevent accidental touches, but the sensor has identification angle limitations causing it to miss obstacles in some scenarios
Solution Approach 1:
The system introduces capacitance data analysis as an intermediary mechanism between the optical sensor and the screen-off decision. The capacitance touchscreen provides additional sensing capability that complements the optical sensor, allowing the system to detect touches that the optical sensor misses due to angle limitations.
Solution Approach 2:
The system makes the touchscreen serve multiple functions: normal touch input and accidental touch detection during calls. By analyzing capacitance distribution patterns across the entire screen surface, the system can identify characteristic patterns of accidental touches (like ear or cheek contact) that differ from normal finger touches.
3Measurement precision
If capacitance touchscreen reports all touch points, then normal touches are accurately detected, but accidental touches from non-finger parts cannot be distinguished leading to misoperations
Solution Approach 1:
The system analyzes local capacitance distribution characteristics at different regions of the touchscreen. By examining the spatial pattern of capacitance changes and comparing them against known patterns of finger versus non-finger touches, the system can identify and filter out accidental touches while preserving normal touch detection.
Solution Approach 2:
The system changes the parameters used for touch detection by analyzing multiple capacitance features simultaneously (such as capacitance magnitude, rate of change, spatial distribution, and temporal patterns). By monitoring changes in these parameters over time, the system can distinguish between legitimate finger touches and accidental contacts from other body parts.
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 suppresses report points from accidental touches without affecting normal operations, enhancing user experience by accurately identifying and preventing misoperations during calls.
Implementation Method 1
In an existing capacitive touchscreen technology, only report point data of an object touching a screen can be calculated
Implementation Method 2
Currently, an optical proximity sensor in a smartphone is usually used to identify an obstacle in front of a screen
Data Source
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AI summary
Embodiments of the present invention provide a report point output control method and apparatus. The method includes: performing feature detection on a capacitance hot spot to determine at least one eigenvalue of the capacitance hot spot (101); determining, based on the at least one eigenvalue of the capacitance hot spot, whether a report point matching the capacitance hot spot is a report point generated by an odd-form touch (102); and if it is determined that the report point is the report point generated by the odd-form touch, skipping outputting the report point (103), where the at least one eigenvalue includes at least one of a horizontal span, a longitudinal span, an eccentricity, a barycenter coordinate, a maximum capacitance value, an average shadow length, an upper left shadow area, and a lower right shadow area. In the method, the report point generated by the odd-form touch can be effectively suppressed.