Touch Detection Circuit Feedback for Display Interference Suppression
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Solution Overview
Problem
The increasing display interference coupled with screen touch sensors reduces the signal-to-noise ratio (SNR) of touch signals, leading to low touch recognition accuracy due to valid touch signals occupying a small portion of the dynamic range after amplification.
Innovation Solution
A touch detection circuit that processes input signals from electrodes, utilizing an amplification module with feedback mechanisms to suppress display interference and base signals, enabling a larger dynamic range for valid touch signals through mean error feedback and analog-to-digital conversion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the touch signal is amplified to recognize valid touch signals, then the touch signal becomes detectable, but the display interference occupies a large portion of the dynamic range causing low touch detection accuracy
Solution Approach 1:
The patent employs feedback mechanisms where the touch detection circuit continuously monitors the output signals and adjusts the amplification and filtering parameters dynamically. The system uses the detected interference patterns to adjust the signal processing in real-time, ensuring that valid touch signals are enhanced while display interference is suppressed through adaptive feedback control
Solution Approach 2:
The patent extracts and separates the display interference component from the composite signal using signal processing techniques. By identifying and isolating the interference portion, the system can remove it from the total signal, leaving only the valid touch signal for accurate detection
2Object-affected harmful factors
If display interference is suppressed using traditional filtering, then some interference is reduced, but the valid touch signal occupying small dynamic range remains undetectable
Solution Approach 1:
The patent dynamically changes the parameters of the signal processing circuit, including amplification gain, filtering characteristics, and integration time, based on the detected signal conditions. By adjusting these parameters in real-time, the system optimizes both interference suppression and touch signal detection sensitivity
3Measurement precision
If the touch signal dynamic range is increased to improve detection accuracy, then valid touch signals become more detectable, but display interference coupling increases due to larger signal amplitude
Solution Approach 1:
The patent introduces intermediary signal processing stages including buffer circuits, impedance matching networks, and isolation components between the electrodes and the amplification circuitry. These intermediaries prevent direct coupling of interference while allowing the valid touch signal to pass through with minimal attenuation
Data Source
AI summary
A touch detection circuit, a touch chip, and a screen module are provided. The touch detection circuit is configured to process input signals to obtain a touch signal corresponding to each of the electrodes. The touch signal is used to indicate a touch state of a touch region where the electrode is located. When no finger touch is present, a touch signal corresponding to each of the electrodes is a first touch signal; and when a finger touch is present, a touch signal corresponding to one of the electrodes located in a touch region with the finger touch is a second touch signal, a touch signal corresponding to one of the electrodes located in a touch region without the finger touch is a third touch signal, and each of the second touch signal and the third touch signal is different from the first touch signal.