Liquid Detection in Self-Capacitance Touch Screens
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Solution Overview
Problem
Self-capacitance touch screens experience severe distortion in detected touch point information when water is present, as the physical characteristics of water drops cause an abnormal increase in sensed values, leading to erroneous touch control signals.
Innovation Solution
A detection method and device that determine a first detection channel's characteristic value when a touch control area is triggered, identifying if the area is covered by liquid by comparing the value to preset thresholds, and if so, not responding to the touch control signal to avoid collecting distorted data. This method involves summing adjacent channel values or counting channels with high values to confirm liquid presence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If self-capacitance touch screen is used to detect touch actions, then touch detection capability is improved, but liquid interference causes severe distortion in detected touch point information
Solution Approach 1:
The touch screen detection system is divided into multiple independent detection channels, each responsible for a specific region. By segmenting the detection area and analyzing characteristic values of individual channels, the system can identify liquid interference in specific regions without affecting the entire screen's touch detection capability.
Solution Approach 2:
The patent introduces an intermediate processing layer that analyzes characteristic values from multiple detection channels before generating final touch control signals. This intermediary analysis step detects abnormal patterns indicating liquid presence and filters out distorted signals, preventing liquid interference from reaching the final touch control output.
2Measurement precision
If multiple detection channels are used to identify liquid coverage, then liquid detection accuracy is improved, but system complexity increases
Solution Approach 1:
The system uses a predetermined number of detection channels around the triggered area, which may be more than the minimum needed. This excessive action ensures that liquid coverage is detected even if it affects only part of the touched area, while the predetermined limit prevents unlimited channel usage and controls system complexity.
Solution Approach 2:
The patent applies different analysis methods to different detection channels based on their characteristic values. Channels with abnormal characteristic values indicating liquid presence are analyzed differently from normal channels, allowing the system to focus computational resources only where needed rather than uniformly processing all channels.
3Speed
If characteristic value threshold comparison is used to detect liquid, then detection speed is improved, but false positives may occur
Solution Approach 1:
The system implements a feedback mechanism where the results from multiple detection channels are cross-validated. When a channel's characteristic value exceeds the threshold, the system checks adjacent channels and uses the collective information to confirm liquid presence, reducing false positives while maintaining fast detection through the threshold-based initial screening.
Solution Approach 2:
The patent performs preliminary analysis by comparing characteristic values against predetermined thresholds before conducting more complex liquid detection algorithms. This preliminary action quickly filters out obvious non-liquid cases and prepares data for further verification, enabling fast initial detection while maintaining reliability through subsequent validation steps.
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
Quickly and accurately determines if a touch control area is covered by liquid, preventing the collection of erroneous signals and maintaining low operational costs, thus ensuring accurate touch control operations.
Implementation Method 1
Self-capacitance touch screens are widely used in the touch screens. However, due to the physical characteristics of self-capacitance touch screens, in a case where water drops on the touch screen, there is no adverse effect when touching other areas which are dry, while a change in the sensed amount much larger than usual would be caused when touching a water-covered area.
Data Source
AI summary
The present disclosure relates to detection methods, devices and electronic equipment. An example method includes determining a first detection channel of a triggered touch control area when a touch control display device is triggered; determining whether the touch control area is covered by liquid according to a characteristic value of a first detection channel based on responsive to determining a sum of characteristic values of adjacent detection channels is greater than or equal to a third preset value, determining that the touch control area is covered by liquid, wherein a second preset value is greater than a first preset value and less than the third preset value; and not responding to a touch control signal of the touch control area collected at a current time under the condition of determining that the touch control area is covered by liquid.