Touch Button Frequency Spreading for Noise-Resistant Input Sensing
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Solution Overview
Problem
Existing electronic devices with touch-based user interfaces incorrectly detect touch inputs due to noise interference at similar frequencies to the operating frequency, leading to erroneous input recognition.
Innovation Solution
The electronic device spreads the operating frequency into a range of frequencies to control charging and discharging of capacitors connected to touch buttons, measuring charging times to accurately determine touch inputs despite noise interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a fixed operating frequency is used to charge and discharge the capacitor, then the device operation is simple and fast, but noise at similar frequencies causes erroneous touch input detection
Solution Approach 1:
The patent applies dynamics by changing the fixed operating frequency to a variable frequency that moves across a frequency range. The controller dynamically adjusts the frequency of the clock signal driving the switch, allowing the system to escape from noise interference at specific frequencies while maintaining reliable touch detection through continuous frequency variation.
Solution Approach 2:
The patent implements parameter changes by modifying the frequency parameter of the operating signal. Instead of using a single fixed frequency, the system varies the frequency within a defined range, which fundamentally changes the operational parameters to avoid resonance with external noise sources and improve detection reliability.
2Reliability
If the operating frequency is spread into multiple frequencies, then noise interference is reduced, but the charging and discharging operation becomes more complex
Solution Approach 1:
The patent applies periodic action by implementing continuous frequency modulation of the clock signal. The frequency varies periodically across the specified range, creating a time-varying operating condition that inherently provides noise rejection. This periodic frequency variation simplifies the control approach compared to complex multi-frequency sequencing while maintaining robustness against narrowband noise.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enhances touch input sensitivity by correctly distinguishing between actual touch inputs and noise-induced false detections, improving user interface reliability.
Implementation Method 1
The touch-based UI may receive the input of the user by determining whether a touch input has occurred based on a change in a capacitance of a capacitor connected to the touch button
Data Source
AI summary
An electronic device includes one or more processors, a memory storing instructions, and a user interface including at least one touch button, a capacitor coupled with the at least one touch button, and a switch configured to charge the capacitor and to discharge the capacitor. The instructions, when executed by the one or more processors individually or collectively, cause the electronic device to spread an operating frequency into a plurality of spread frequencies within a frequency range, determine, based on the plurality of spread frequencies, whether to at least one of charge the capacitor or discharge the capacitor by controlling the switch to at least one of turn on or turn off, measure a charging time of the capacitor, according to the controlling of the switch, and determine whether a touch input on the at least one touch button occurs, based on the measured charging time.