Touch Sensor Array Phase Offset Grounding Instability
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Solution Overview
Problem
Touch sensors face performance degradation due to unstable grounding states, which can lead to incorrect touch input recognition and 'ghost' phenomena, especially when the grounding state is unstable, affecting the accuracy of touch input detection.
Innovation Solution
The implementation of a touch sensor system where driving signals with opposite phases are applied to adjacent touch nodes, effectively offsetting the changes in self-capacitance and minimizing their impact on mutual capacitance, thereby improving sensor performance even in unstable grounding conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional touch sensor operation is used, then the sensor can detect touch inputs, but performance degrades when grounding state is unstable due to self-capacitance changes
Solution Approach 1:
The patent applies preliminary anti-action by driving adjacent touch nodes with opposite phase signals before reading their states. This pre-applied opposite phase creates a counterbalancing effect that cancels out the harmful influence of unstable grounding and self-capacitance changes, preventing performance degradation before it occurs.
Solution Approach 2:
The patent changes the phase parameter of the driving signal applied to adjacent touch nodes. By alternating the phase (0° or 180°) of driving signals between neighboring touch nodes, the system creates differential measurement conditions that eliminate the common-mode noise from unstable grounding, thereby maintaining reliable touch detection.
2Area of stationary object
If driving signals are applied to all touch nodes simultaneously, then touch detection coverage is maximized, but self-capacitance changes cause ghost phenomena and incorrect recognition
Solution Approach 1:
Before reading the state of touch nodes, the patent pre-drives adjacent touch nodes with opposite phase signals. This preliminary action creates opposite polarity charges that cancel each other's electromagnetic interference, preventing ghost phenomena and incorrect touch recognition while maintaining full detection coverage.
Solution Approach 2:
The patent applies different phase driving signals to different spatial locations (adjacent touch nodes). Each touch node receives a driving signal with a specific phase relationship to its neighbors, creating local differential measurement zones that eliminate interference while preserving global detection capability.
3Reliability
If opposite phase driving signals are applied to adjacent touch nodes, then self-capacitance influence is reduced, but system complexity increases
Solution Approach 1:
The patent segments the touch node array into adjacent pairs or groups that receive opposite phase driving signals. This segmentation allows the complex opposite-phase driving to be implemented in a modular fashion, where each segment handles its own differential signaling independently, reducing overall system complexity while maintaining performance stability.
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 and reliability of touch input detection by reducing the influence of self-capacitance changes, preventing performance degradation and 'ghost' phenomena, even when the grounding state is unstable.
Implementation Method 1
A touch sensor sensing a touch input using a change in capacitance may be classified into a first sensing type using a change in self-capacitance or a second sensing type using a change in mutual capacitance
Data Source
AI summary
A touch sensor including a sensor array including a first touch node and a second touch node adjacent to each other in at least one of a first direction or a second direction, the second direction perpendicular to the first direction, the first touch node and the second touch node electrically separated from each other, each of the first touch node and the second touch node including a driving electrode and a sensing electrode, and a controller configured to output a first driving signal having a first phase to the driving electrode of the first touch node and output a second driving signal having a second phase opposite to the first phase of the first driving signal to the driving electrode of the second touch node may be provided. The controller may be further configured to output the first driving signal and the second driving signal simultaneously.