Touch Panel Noise Interference Suppression via Dynamic Frequency Adjustment
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Solution Overview
Problem
Touch panels with projected capacitive touchscreen technology face incorrect operations due to interference from disturbance noise, particularly when the noise frequency fluctuates, and existing methods either cause temporary disruptions during frequency adjustments or fail to completely exclude noise influence.
Innovation Solution
A touch panel apparatus that includes a touch sensor panel, a drive part outputting pulses with varying frequencies, a sensing part measuring capacitance, and a data determination part identifying abnormal measurements, allowing the drive part to adjust frequencies and output non-interfering pulses, ensuring accurate coordinate detection even during frequency changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the drive frequency of the touch panel is dynamically changed to prevent interference with disturbance noise, then the reliability of touch operation is improved, but incorrect operations may occur during the frequency change process
Solution Approach 1:
The system performs preliminary detection of disturbance noise frequency before changing the drive frequency. The noise detection unit identifies the disturbance noise frequency in advance, allowing the drive frequency to be changed proactively to avoid interference, rather than reactively after interference occurs. This preliminary action ensures that the frequency change is timed appropriately to prevent both interference and incorrect operations during transition.
2Measurement precision
If the drive frequency is dynamically changed to avoid disturbance noise interference, then measurement precision is improved, but the system becomes vulnerable when disturbance noise frequency fluctuates
Solution Approach 1:
The system continuously monitors the disturbance noise frequency through the noise detection unit and provides feedback to the drive frequency control unit. When the detected noise frequency changes, the system adjusts the drive frequency accordingly in real-time. This feedback mechanism ensures that the touch panel maintains high measurement precision even when the disturbance noise frequency fluctuates, as the drive frequency dynamically adapts to avoid interference.
3Reliability
If multiple drive pulses with different pulse widths are used to suppress incorrect operations, then reliability is improved, but the processing time increases due to multiple scans
Solution Approach 1:
Instead of using multiple drive pulses with different pulse widths requiring multiple scans, the system changes the frequency parameter of the drive pulse. The noise detection unit identifies the disturbance noise frequency, and the drive frequency control unit adjusts the drive pulse frequency to avoid interference. This single-scan frequency-based approach maintains high touch detection accuracy while significantly improving processing speed compared to multi-scan pulse width variation methods.
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
The apparatus consistently suppresses incorrect operations by detecting and excluding disturbance noise, enabling normal operation during dynamic frequency changes and fluctuating noise frequencies.
Implementation Method 1
a sensing part connected to the touch sensor panel and measures a capacitance for each of the plurality of drive pulses
Data Source
AI summary
A touch panel apparatus includes: a data determination part determining whether a measurement value of a capacitance for each of a plurality of drive pulses measured by a sensing part is normal or abnormal; and a coordinate detection part outputting a touch coordinate position of a touch performed by an indication body in accordance with the measurement value of the capacitance which is determined to be normal by the data determination part, wherein the drive part changes a frequency of a drive pulse in the plurality of drive pulses corresponding to the measurement value of the capacitance which is determined to be abnormal by the data determination part, and outputs, in a subsequent scan, a plurality of drive pulses including a drive pulse whose frequency has been changed.