Touch Screen Driving with Image-Based Reference Noise Cancellation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The increasing proximity between display panels and touch sensors in ultra-thin touch screens leads to increased parasitic capacitances, causing display noise to interfere with touch sensing signals, thereby deteriorating touch sensing sensitivity.
Innovation Solution
A touch sensor controller generates a reference signal based on an input image signal and a receiver removes noise from sensing signals using this reference signal, while a touch screen driving circuit produces source signals and touch signals based on input image signals to enhance touch sensing sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the distance between display panel and touch sensor is reduced to achieve ultra-thin touch screens, then the thickness of the touch screen is reduced, but parasitic capacitances increase causing display noise to interfere with touch sensing signals
Solution Approach 1:
The patent introduces a reference signal as an intermediary to cancel out the harmful parasitic capacitance effects. The reference signal generator creates a signal that mirrors the noise introduced by parasitic capacitances, and this reference signal is fed back to the touch sensor controller to subtract from the sensing signal, thereby eliminating the harmful interference without changing the physical distance between components
Solution Approach 2:
The patent changes the electrical parameters of the touch sensor system by dynamically adjusting the reference signal based on the input image signal. The reference signal generator modifies the signal parameters to match the noise characteristics caused by parasitic capacitances, allowing for compensation through parameter adjustment rather than physical redesign
2Measurement precision
If display noise is removed from sensing signals to improve touch sensing sensitivity, then the signal quality is improved, but additional signal processing complexity is introduced
Solution Approach 1:
The patent creates a copy of the noise signal through the reference signal generator, which replicates the parasitic capacitance effects without requiring direct measurement or complex analysis of the original noise. This copy is then used to subtract from the sensing signal, simplifying the processing compared to analyzing and filtering complex noise patterns
Solution Approach 2:
The patent implements a feedback mechanism where the reference signal, generated from the input image signal, is fed back to the touch sensor controller to dynamically compensate for noise. This feedback loop automatically adjusts to changing display conditions, maintaining signal quality without requiring complex manual processing
Data Source
AI summary
A touch sensor controller according to some implementations includes a reference signal generator generating a reference signal based on an input image signal and a receiver connected to a touch electrode, receiving a sensing signal from the touch electrode, and generating an output signal based on difference between the reference signal and the sensing signal.