Touch Controller Demodulation for Accurate Noise Detection
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Solution Overview
Problem
Touch panels face reduced accuracy due to noise contamination in sensing signals, which degrades their performance in detecting touch events.
Innovation Solution
A touch controller and noise detection method that utilize a demodulator with a first filter configured to perform noise detection operations on sensing signals, using a low-pass filter and a first filter with peak frequencies adjacent to the sensing signal frequency to output a noise detection signal, allowing for simultaneous touch and noise detection during touch detection periods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a touch panel performs sensing operations to detect touch events, then touch detection capability is provided, but the sensing signal becomes contaminated by noises that degrade detection accuracy
Solution Approach 1:
The patent segments the sensing signal processing into multiple frequency components using a filter bank structure. The sensing signal is divided into different frequency bands, allowing selective filtering of noise components while preserving the useful sensing information. This segmentation enables targeted noise removal without affecting the overall touch detection capability.
Solution Approach 2:
The patent introduces an intermediary processing stage between signal reception and touch detection. A noise detection signal is generated as an intermediate representation that captures noise characteristics separately from the main sensing signal. This intermediary signal allows the system to identify and mitigate noise effects without directly interfering with the primary touch sensing operation.
2Measurement precision
If traditional filtering methods are used to remove noise from sensing signals, then some noise reduction is achieved, but detection accuracy is not sufficiently improved due to insufficient noise characterization
Solution Approach 1:
The patent employs dynamic filter coefficient adjustment based on real-time noise characteristics. The filter bank adapts its parameters according to the detected noise profile, allowing the system to optimize noise filtering performance for different noise conditions. This dynamic adaptation enables more accurate noise detection and removal compared to static filtering methods.
Solution Approach 2:
The patent changes the frequency domain parameters of the sensing signal by transforming it into multiple frequency components. By representing the signal in the frequency domain rather than time domain, the system can more effectively identify and separate noise components from useful signal components, thereby improving measurement precision in noise detection.
3Measurement precision
If the sensing signal is processed to improve noise detection, then detection accuracy improves, but processing complexity increases
Solution Approach 1:
The patent segments the complex processing task into manageable frequency bands using a filter bank. Each band can be processed independently with simpler algorithms, reducing the overall computational complexity compared to processing the entire signal spectrum at once. This segmentation makes the noise detection system more implementable while maintaining high detection accuracy.
Solution Approach 2:
The patent applies partial processing to the sensing signal by focusing computational resources on detecting noise in specific frequency ranges where noise is most likely to occur. Rather than analyzing all frequency components equally, the system concentrates processing effort on critical regions, achieving effective noise detection with reduced overall processing complexity.
Data Source
AI summary
A touch controller and a noise detection method that are capable of accurately detecting noises in a sensing signal are introduced. The touch controller may include a demodulator that is configured to receive a sensing signal and demodulate the sensing signal with a first frequency during a touch detection period. The demodulator may include a first filter that is configured to perform a noise detection operation on the sensing signal to output a first noise detection signal with a second frequency range adjacent to the first frequency. The first filter may have a plurality of peak frequencies different from the first frequency.