Capacitive Sensor Reference Value Update Logic
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Solution Overview
Problem
Existing methods for updating reference values in capacitive sensors are prone to mistaken decisions due to non-uniformity in detected values caused by environmental factors, and cannot be applied when a single sensor is used.
Innovation Solution
An input device and method that suppresses the update of reference values by adjusting the decision reference based on the proximity of the object, using a detecting unit that generates detection signals and a deciding unit that evaluates these signals to prevent updates during object approach.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a reference value is updated when detected values are within a certain range, then the reference value can be maintained accurately when the target is not approaching, but the reference value may be mistakenly updated when the target is approaching
Solution Approach 1:
The patent applies dynamics by making the reference value updating unit dynamically adjust its behavior based on real-time detection results. The system continuously monitors detected values and automatically determines whether to update the reference value or maintain the current one, based on whether the target is approaching or not. This dynamic adaptation resolves the contradiction by enabling accurate reference value maintenance while preventing mistaken updates during target approach.
Solution Approach 2:
The patent implements feedback through the reference value updating unit that uses detected values as feedback to control reference value updates. The system forms a closed-loop control where detection results feed back to the updating unit, which then adjusts the reference value accordingly. This feedback mechanism ensures that reference values are updated only when appropriate (when target is not approaching) while maintaining accuracy when the target is absent.
2Adaptability or versatility
If the reference value is updated frequently to adapt to environmental changes, then the sensor can maintain accuracy under varying conditions, but the system becomes more susceptible to mistaken updates when the target is nearby
Solution Approach 1:
The system dynamically adjusts the reference value based on environmental conditions while simultaneously monitoring for target presence. The reference value updating unit evaluates both environmental changes and target proximity indicators, updating the reference value only when environmental adaptation is needed and the target is not present. This dynamic dual-condition control resolves the contradiction between environmental adaptability and detection accuracy.
Solution Approach 2:
The patent changes the reference value parameter dynamically based on environmental conditions and target presence. The reference value updating unit modifies this parameter only when environmental changes are detected and the target is not approaching, as determined by the detection unit. This selective parameter change strategy enables environmental adaptation while preventing mistaken updates that would compromise detection accuracy.
3Device complexity
If a single sensor is used for proximity detection, then the device complexity is reduced, but the system cannot determine whether changes are due to environmental factors or target approach
Solution Approach 1:
The patent applies segmentation by dividing the functionality of a complex multi-sensor system into a single integrated sensor unit with multiple operational modes. The detection unit within the single sensor is configured to detect both environmental changes and target approach indicators, effectively segmenting the detection capabilities within one device. This segmentation approach maintains low device complexity while enabling change source discrimination through intelligent signal analysis.
Solution Approach 2:
The single sensor used in the patent is designed with multi-functionality, serving both environmental monitoring and target detection purposes. The detection unit can operate in different modes to identify whether detected changes are due to environmental factors or target approach. This universal sensor design resolves the contradiction by eliminating the need for multiple specialized sensors while maintaining the ability to discriminate change sources through its versatile detection capabilities.
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
Effectively prevents mistaken decisions about object proximity by reducing the likelihood of reference value updates during object approach, while allowing for accurate updates when the object is not approaching.
Implementation Method 1
Self-capacitance type of sensors that detect capacitance between an object and a detection electrode
Data Source
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AI summary
An input device has: a detecting unit that generates a detection signal that changes according to the degree of the proximity of an object; a deciding unit that decides, according to a series of detection signals generated in the detecting unit, whether a change is present in the detection signals along with the proximity of the object; and a reference value updating unit that, if the deciding unit decides that a change is not present in the detection signals along with the proximity of the object, updates a reference value indicating the value of the detection signal in a state in which the object is not approaching, according to the detection signals generated in the detecting unit. The deciding unit changes a decision reference so that the higher the degree of the proximity of the object, the degree being indicated by the difference between the detection signal and the reference value, is, the more likely the deciding unit is to decide that a change is present in the detection signals along with the proximity of the object.