Multi-Touch Integrity Sensing for Capacitive Touch Screens
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Solution Overview
Problem
Capacitive touchscreen panels face challenges in accurately distinguishing between user touches and unwanted foreign matter, such as water, due to the limitations of mutual-capacitance and self-capacitance modes, which can lead to data integrity issues and incorrect touch detection.
Innovation Solution
A method and system for touch island integrity checking that identifies touched nodes using both mutual and self-capacitance modes, creates a processing mask, and classifies nodes to determine the integrity of touch islands, ensuring accurate detection by switching between modes based on integrity rules.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If mutual-capacitance mode is used for touch detection, then multi-touch detection capability is improved, but false detection of foreign matter such as water increases
Solution Approach 1:
The patent divides the touch detection process into two separate modes (mutual-capacitance mode and self-capacitance mode) that operate independently. Each mode has its own sensing mechanism and data processing path, allowing the system to segment the detection function to leverage the strengths of each mode while avoiding their individual weaknesses.
Solution Approach 2:
The patent implements a nested structure where self-capacitance touched nodes are used to create a processing mask that overlays and constrains the mutual-capacitance touched nodes. The integrity checking process nests multiple verification layers (node mapping overlay, touch island integrity rules) within the touch detection framework, with each layer refining the accuracy of the final touch detection result.
2Reliability
If self-capacitance mode is used for touch detection, then water rejection capability is improved, but multi-touch detection accuracy deteriorates
Solution Approach 1:
The patent merges the results from both mutual-capacitance mode and self-capacitance mode through an integrity checking process. The system combines the multi-touch detection capability of mutual-capacitance with the water rejection capability of self-capacitance by cross-validating touched nodes from both modes against integrity rules, achieving both functionalities simultaneously.
Solution Approach 2:
The patent introduces a processing mask generated from self-capacitance touched nodes as an intermediary element. This mask acts as a mediator that filters and validates the touched nodes detected by mutual-capacitance mode, enabling the system to reconcile the conflicting capabilities of the two modes through a intermediate verification layer.
3Measurement precision
If integrity checking process is implemented, then touch detection accuracy is improved, but processing complexity increases
Solution Approach 1:
The patent performs preliminary actions by first identifying self-capacitance touched nodes and generating a processing mask before validating the mutual-capacitance touched nodes. This preliminary step prepares the validation framework in advance, organizing the integrity checking process into a structured sequence that reduces the complexity of the overall validation operation.
Solution Approach 2:
The patent changes the parameters of touched nodes by creating different representations (node mapping overlay, processing mask) from the raw capacitance data. By transforming the data into different parameter forms suitable for specific validation rules, the system simplifies the integrity checking process 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
This approach enhances the accuracy of touch detection by combining data from both modes, reducing false positives and improving data reliability, enabling effective multi-touch detection and water rejection in capacitive touchscreen panels.
Implementation Method 1
The capacitive sensing panel may evaluate changes in capacitance at each capacitive node to detect a user touch or hover
Data Source
AI summary
A method for multi-touch integrity sensing for a multi-touch capacitive touch screen is disclosed. By determining the integrity of touches, a distinction is identified between wanted touches, such as via a finger or stylus, and unwanted touches such as via foreign matter, errors, and the like.