Capacitive Sensor I/Q Reference Compensation for Stable Touch Detection
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Solution Overview
Problem
Capacitive sensor devices are prone to reliability issues due to humidity, pollution, and environmental effects, affecting the accuracy of manual exertion detection.
Innovation Solution
The method involves exposing at least three predetermined reference impedances to a sinewave-based electric signal, processing the resulting I-signals and Q-signals alongside reference I-signals and Q-signals to enhance the detection of manual exertion by reducing interference from environmental factors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If capacitive sensor devices are used for manual exertion detection, then simple manipulation and control are achieved, but reliability deteriorates due to humidity, pollution, and environmental effects
Solution Approach 1:
The patent transforms the raw sensor signal from impedance domain to admittance domain (I/Q signals), and further processes them through reference-based compensation to extract temperature-stable features. This parameter transformation enables the system to maintain reliability under varying environmental conditions while preserving the simple capacitive sensing interface.
Solution Approach 2:
The patent introduces reference impedances as intermediary elements that mediate between the environmental disturbances and the measurement process. These reference impedances experience the same environmental effects as the sensor but are known and stable, allowing the system to compensate for environmental variations by comparing sensor signals against reference signals.
2Device complexity
If traditional capacitive sensing is used, then device complexity is low, but measurement precision deteriorates due to environmental interference
Solution Approach 1:
The patent segments the measurement process into distinct stages: raw signal acquisition, I/Q transformation, reference signal processing, and compensated measurement extraction. This segmentation allows each stage to be optimized independently, maintaining overall system simplicity while achieving high measurement precision through systematic signal processing.
Solution Approach 2:
The patent replaces direct physical measurement of capacitance changes with an electrical signal processing approach using I/Q transformation and reference-based compensation. This substitution of mechanical/electrical measurement methods with signal processing techniques enables high precision measurement while keeping the physical sensor structure simple.
3Reliability
If reference impedances are introduced for compensation, then reliability improves by reducing environmental interference, but device complexity increases
Solution Approach 1:
The patent makes the reference impedances serve multiple functions: they act as environmental sensors, calibration standards, and compensation references simultaneously. This multi-functionality allows the reference impedances to provide comprehensive environmental compensation without requiring separate dedicated components for each function, thereby limiting the increase in device complexity.
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 improves the reliability and stability of manual exertion detection by compensating for interference, particularly from temperature and humidity, enhancing the accuracy of capacitive sensor devices.
Implementation Method 1
at least one capacitive sensor element of the capacitive sensor device is exposed to a sinewave-based first electric signal, wherein the at least one capacitive sensor element provides a second electric signal in response to exposition with the first electric signal
Implementation Method 2
the second electric signal is input to an in-phase-detector, in order to provide an I-signal in response to the second electric signal, and a quadrature-phase-detector, in order to provide a Q-signal in response to the second electric signal
Data Source
AI summary
A method for ascertaining manual exertion of a capacitive sensor device, wherein a capacitive sensor element of the capacitive sensor device is exposed to a sinewave-based first electric signal, wherein the capacitive sensor element provides a second electric signal, wherein the second electric signal is input to an in-phase-detector, in order to provide an I-signal, and a quadrature-phase-detector, in order to provide a Q-signal, wherein the I-signal and the Q-signal are processed in order to allow ascertaining the manual exertion. Three predetermined reference impedances are also exposed to the first electric signal, wherein the predetermined reference impedances provide respective second electric reference signals which are input to the in-phase-detector and the quadrature-phase-detector, in order to provide respective reference I-signals and respective reference Q-signals, the reference I-signals and the reference Q-signals are additionally processed.