Touch Screen SNR Optimization via Capacitance Filtering
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Solution Overview
Problem
Conventional touch screen technologies experience lower signal-to-noise ratio (SNR) parameters due to noise interference, leading to reduced accuracy in identifying touch actions.
Innovation Solution
A method and device that filter capacitance signals from both untouched and touched touch screens to eliminate spike noise, calculate and compensate average values, and determine the SNR parameter using specific ratios to enhance the SNR, thereby improving touch action identification accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional algorithms (standard deviation, RMS, or peak-to-peak) are used to calculate the SNR parameter, then the calculation process is simple, but the calculated SNR parameter value is lower, resulting in lower touch action identification accuracy
Solution Approach 1:
The patent segments the capacitance signal processing into multiple stages: filtering stage (separating spike noise), averaging stage (calculating average values in single period), and compensation stage (adjusting average values). This segmentation transforms the simple but inaccurate conventional calculation into a multi-step process that systematically improves measurement precision while keeping each individual step manageable.
Solution Approach 2:
The patent applies preliminary filtering actions to the capacitance signals before calculating the SNR parameter. By pre-filtering both the touched and untouched screen capacitance signals to remove spike noise, and pre-calculating average values, the system prepares cleaner data for the final SNR calculation, thereby improving the accuracy of the measurement without significantly increasing overall complexity.
2Object-affected harmful factors
If capacitance signals are filtered to eliminate spike noise, then the filtered capacitance signal becomes smoother and noise is reduced, but additional processing steps are required
Solution Approach 1:
The patent extracts and removes the harmful spike noise components from the capacitance signals through filtering operations. By taking out the noise elements from both the touched and untouched screen capacitance signals, the system isolates the useful signal components, thereby reducing noise interference while the filtering operations remain standard signal processing steps.
Solution Approach 2:
The patent converts the harmful effect of spike noise into a benefit by using the filtering process to not only remove noise but also to smooth the capacitance signals and enable more accurate average value calculations. The noise removal process itself becomes beneficial by providing cleaner data for subsequent compensation and SNR calculation steps.
Data Source
AI summary
The present disclosure discloses a method and a device of optimizing a SNR parameter. The method of optimizing the SNR parameter comprises: obtaining a capacitance signal of a touch screen without being touched and a capacitance signal of the touch screen being touched, respectively; filtering the capacitance signal of the touch screen without being touched to obtain a first filtered capacitance signal; filtering the capacitance signal of the touch screen being touched to obtain a second filtered capacitance signal; calculating an average value of the first filtered capacitance signal in a single period and an average value of the second filtered capacitance signal in the single period; compensating the average value of the first filtered capacitance signal or the average value of the second filtered capacitance signal; and determining the SNR parameter, according to a ratio of the compensated average value of the second filtered capacitance signal to the average value of the first filtered capacitance signal, or according to a ratio of the average value of the second filtered capacitance signal to the compensated average value of the first filtered capacitance signal. The method and the device of optimizing the SNR parameter are used for optimizing the SNR parameter applied to a touch screen, solving a problem of low accuracy of identifying a touch action by the touch screen.