Displacement Sensing with Acceleration Compensation for False Inputs
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Solution Overview
Problem
Existing displacement sensing technologies face challenges in distinguishing between user-induced displacements and inertial effects caused by mechanical perturbations, leading to false positives in touch-sensitive input devices.
Innovation Solution
A sensing apparatus combining displacement and acceleration sensors, where the processing circuitry uses the acceleration sensor output to differentiate between user-applied forces and inertial effects by setting a baseline displacement sensor output when acceleration exceeds a threshold, thereby correcting for false positives.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a displacement sensor is used to detect user input by measuring separation distance between a displacement element and a reference element, then touch-sensitive input detection is enabled, but false positive detections occur when the reference element undergoes acceleration due to mechanical perturbations
Solution Approach 1:
An acceleration sensor is introduced as an intermediary component to detect mechanical perturbations of the reference element. The processing circuitry uses this acceleration data as a mediator to distinguish between genuine user inputs and false positives caused by device acceleration, thereby resolving the reliability issue while maintaining touch-sensitive input detection capability
Solution Approach 2:
The system implements feedback by continuously monitoring acceleration data from the acceleration sensor and using this information to adjust the interpretation of displacement sensor readings. When acceleration exceeds a threshold, the system adjusts its detection logic to account for inertial effects, providing dynamic feedback that prevents false positive detections while maintaining accurate user input recognition
2Stability of the object's composition
If the reference element is mechanically coupled to the device housing to provide a stable reference, then structural stability is improved, but acceleration of the housing causes inertial effects that corrupt displacement measurements
Solution Approach 1:
The acceleration sensor serves as an intermediary that monitors the mechanical state of the reference element. By detecting acceleration events, it provides information that allows the processing circuitry to compensate for inertial effects on the displacement measurements, thereby maintaining measurement precision despite the reference element being coupled to the accelerating housing
Solution Approach 2:
The system dynamically changes the interpretation parameters of displacement measurements based on acceleration data. When acceleration exceeds a threshold, the system adjusts its detection thresholds and baseline references to account for the changed mechanical state, thereby maintaining measurement precision under varying acceleration conditions
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
The solution effectively discriminates between user-induced displacements and inertial effects, reducing false positive detections and improving the accuracy of touch-sensitive input recognition.
Implementation Method 1
the sensor element comprises a displacement sensor arranged to sense separation between the frame element and the displacement element based on capacitive coupling between a deformable electrode and a reference electrode
Implementation Method 2
the sensor element comprises an acceleration sensor arranged to sense acceleration of the frame element
Data Source
Figure 1~3
Figure 4~5A
Figure 5B~5C
AI summary
A sensing apparatus comprising a displacement sensor element arranged to sense a separation between a first element (2) and a second element (3) movably mounted with respect to the first element; an acceleration sensor element configured to sense an acceleration associated with the first element; displacement measurement circuitry (4A) configured to make a measurement indicative of separation on the basis of the sensed separation; acceleration measurement circuitry (4C) configured to make a measurement of acceleration on the basis of the sensed acceleration; and a processing element (4D) configured to output a signal to indicate there is determined to be a change in the separation of the second element relative to the first element on the basis of the measurement indicative of separation and the measurement of acceleration.