Dynamic Reference Channel Selection for Touch Detection Accuracy
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Solution Overview
Problem
Capacitive touch control devices face inaccuracies in touch location detection due to common-mode noise from irregular voltage differences and the use of dummy reference channels, leading to false or missing touch responses.
Innovation Solution
A touch detection method using M drive channels and N sense channels, where coded data is loaded, decoded, and differential signals are formed to reduce common-mode noise, with a dynamically chosen reference channel selected based on touch response detection to improve accuracy, allowing for expanded touch control range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a dummy reference channel is used to reduce common-mode noise, then noise suppression is improved, but the reliability of touch detection deteriorates when the reference channel is abnormal
Solution Approach 1:
The patent applies dynamics by transitioning from a static dummy reference channel to a dynamic reference channel selection mechanism. The system dynamically identifies and selects a valid reference channel from multiple sense channels based on real-time signal quality assessment, ensuring the reference channel remains reliable under varying operating conditions while maintaining noise suppression effectiveness.
Solution Approach 2:
The patent changes the parameter of reference channel selection from a fixed dummy channel to a dynamically selected channel based on signal characteristics. By monitoring signal quality parameters and selecting the optimal reference channel, the system adapts to different operational states and maintains high detection accuracy while suppressing common-mode noise.
2Area of stationary object
If multiple sense channels are used to improve touch detection coverage, then the touch control range is improved, but the complexity of noise filtering and reference channel selection increases
Solution Approach 1:
The patent applies segmentation by dividing the sense channels into functional groups and processing them in stages. First, differential signals are generated from adjacent channel pairs, then reference channels are selected from these differential signals, and finally touch detection is performed. This segmented approach manages the complexity of multiple channels while maintaining comprehensive touch detection coverage.
Solution Approach 2:
The system uses self-service by having the sense channels themselves provide the reference signal needed for noise cancellation. Instead of requiring an external dummy reference channel, the system selects a valid reference channel from among the sense channels, allowing the system to self-calibrate and eliminate the need for additional reference components.
3Object-affected harmful factors
If differential signals are formed from all sense channels to reduce noise, then noise suppression is improved, but the processing time and computational load increase
Solution Approach 1:
The patent applies preliminary action by pre-forming differential signals from adjacent sense channel pairs before touch detection. This preliminary processing organizes the data in a way that facilitates efficient reference channel selection and subsequent touch detection, reducing the computational burden during actual touch events while maintaining effective noise suppression.
Data Source
AI summary
A touch detection method, a touch control chip and a touch control display device are disclosed. In the touch detection method, coded data is loaded in drive channels and collected from sense channels. The collected data is decoded and subjected to differential processes. This results in a reduced common-mode signal, interference and noise. A touch response detection is carried out to choose at least one sense channel without touch response from sense channels as reference channel. This dynamically chosen reference channel reduces the risk of inaccurate touch location inference caused by abnormalities of static dummy reference channel and helps improve touch location detection accuracy, sense channels close to ends of capacitive touch control device are allowed to participate in touch response detection as other sense channels do, resulting in an expanded touch control range. The touch control chip and touch control display device all have similar advantages.