Capacitive Sensor Hover Height Detection via Signal Profile Fitting
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Solution Overview
Problem
Current input devices lack reliable techniques for accurately detecting the hover height of an input object, which limits their utility in providing precise interfaces for electronic systems.
Innovation Solution
A processing system that acquires changes in capacitance in a sensing region using capacitive sensors, determines a signal profile, fits a mathematical function to the profile with a fitting parameter that correlates to hover height, and adjusts the parameter to calculate and output the hover height, enabling accurate hover height estimation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional capacitive sensing is used to detect input objects, then the presence and location of objects can be determined, but accurate hover height detection is not reliable
Solution Approach 1:
The patent applies parameter changes by utilizing multiple capacitance measurement parameters (C0, C1, C2, C3) that correspond to different spatial relationships between the input object and sensor electrodes. By measuring capacitance changes across multiple parameters and analyzing their relationships, the system can accurately determine hover height. The mathematical model relates these capacitance parameters to hover height through a function that captures the physical relationship between capacitance measurements and object distance, enabling precise height detection that conventional single-parameter sensing cannot achieve.
2Measurement precision
If multiple sensor electrodes are used to improve sensing capability, then more capacitance data can be collected, but the device complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the sensing area into multiple zones with different sensor electrodes (first, second, third, and fourth sensor electrodes). Each electrode segment measures capacitance changes from different spatial perspectives. This segmented approach allows the system to collect multiple capacitance parameters (C0, C1, C2, C3) that provide complementary information about the input object's position and height, enabling accurate hover detection while maintaining a manageable electrode configuration.
Solution Approach 2:
The patent applies universality by designing sensor electrodes that serve multiple functions: they detect both the presence/location of input objects and the hover height above the surface. The same set of four sensor electrodes used for basic touch detection also provides the capacitance data needed for height measurement through the mathematical model. This multi-functionality eliminates the need for separate height sensing mechanisms, reducing overall device complexity while achieving accurate hover detection.
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 solution allows for precise detection of hover height, enhancing the functionality of input devices by providing reliable and accurate hover detection, thereby improving user interaction with electronic systems.
Implementation Method 1
acquire changes of capacitance in a sensing region associated with a plurality of sensor electrodes in a capacitive sensor
Data Source
AI summary
Techniques for estimating height of an input object in a sensing region of an input device are provided. The techniques include constructing a signal profile based on measured data. The techniques also include determining a fit value of a fitting parameter of a mathematical function that fits the mathematical function to the signal profile such that the fitting of the mathematical exceeds a quality threshold. The fitting parameter correlates to hover height of the input object and adjusting the fitting parameter affects the fit of the mathematical function to the signal profile. In some embodiments, fitting a curve includes varying the height parameter of a mathematical function until the curve generated by the mathematical function with the selected height parameter is deemed to fit obtained sensor data to within a certain tolerance. In other embodiments, fitting a curve may be accomplished with direct computation.