Transcapacitive Sensing with Non-Adjacent Electrode Coupling
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Solution Overview
Problem
Conventional capacitive sensor systems are not well-suited for proximity sensing due to high background couplings and low signal-to-noise ratio (SNR), limiting their ability to detect input objects near but not in contact with the sensing surface.
Innovation Solution
The method involves driving non-intersecting electrodes using specific basis functions to distinguish between capacitive couplings between adjacent and non-adjacent electrodes, enhancing the signal-to-noise ratio for accurate proximity sensing through transcapacitive sensing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional transcapacitive sensing is used for proximity sensing, then the sensing capability is provided, but the signal-to-noise ratio is low
Solution Approach 1:
The patent segments the capacitive sensing measurements by separating nearest-neighbor capacitance measurements from non-adjacent electrode capacitance measurements. This segmentation allows the system to isolate and process the relevant proximity sensing signals (nearest-neighbor) separately from the background noise (non-adjacent), thereby improving the signal-to-noise ratio for proximity detection
Solution Approach 2:
The patent extracts and removes the capacitive coupling contributions from non-adjacent electrode pairs from the total capacitance measurements. By taking out this background coupling component, the system isolates the nearest-neighbor capacitance signals that carry the proximity sensing information, significantly improving measurement precision
2Device complexity
If conventional absolute capacitance systems are used for proximity sensing, then the system is simple, but the background couplings are high
Solution Approach 1:
The patent introduces an intermediary processing step that measures and characterizes the capacitive coupling between non-adjacent electrode pairs. This intermediary measurement serves as a reference for the background coupling, which is then subtracted from the total capacitance measurements to isolate the proximity sensing signals, effectively reducing background coupling without requiring complete system redesign
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 signal-to-noise ratio, enabling effective proximity sensing and providing capacitance information for nearest-neighbor, second-nearest-neighbor, and third-nearest-neighbor pairs of electrodes, enhancing the accuracy of capacitive sensing systems.
Implementation Method 1
capacitive sensor device determines the presence, location and/or motion of one or more input objects... capacitance information for pairs of electrodes... capacitance information for nearest-neighbor pairs of electrodes... capacitance information for second nearest-neighbor pairs of electrodes
Data Source
AI summary
A method for capacitive sensing includes: driving, by a processing system, a first plurality of transmitter electrodes using a first plurality of basis functions, wherein the first plurality of transmitter electrodes are part of a first set of non-intersecting electrodes which are arranged adjacently to one another in a first orientation; and obtaining, by the processing system, via a first plurality of receiver electrodes of the first set of non-intersecting electrodes, a first plurality of resulting signals corresponding to the first plurality of basis functions driven onto the first plurality of transmitter electrodes. The first plurality of resulting signals includes: capacitance information for nearest-neighbor pairs of electrodes of the first set of non-intersecting electrodes; capacitance information for second nearest-neighbor pairs of electrodes of the first set of non-intersecting electrodes; and/or capacitance information for third nearest-neighbor pairs of electrodes of the first set of non-intersecting electrodes.