Electrostatic Sensor Water Interference Compensation
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Solution Overview
Problem
Conventional electrostatic detection sensors struggle to accurately detect objects, such as fingers, when exposed to water, leading to false negatives or failures in operation determination due to environmental changes and water interference.
Innovation Solution
The electrostatic detection sensor employs a controller that calculates changes in capacitance between a first electrode and a second electrode under different conditions, including coupled scanning, grounded electrodes, and time-based intensity comparisons to differentiate between object presence and environmental or water-induced changes, ensuring accurate operation determination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional electrostatic detection sensors are used, then the sensor can detect objects under normal conditions, but the detection accuracy deteriorates when exposed to water due to environmental changes and water interference
Solution Approach 1:
The sensor body is divided into multiple independent electrodes (first electrode, second electrode, third electrode) that can be controlled independently. This segmentation allows the patent to measure different capacitance values under different connection conditions (all connected, first and second connected, second and third connected, all grounded), enabling the system to differentiate between object presence and water interference through comparative analysis of multiple measurements
Solution Approach 2:
The patent changes the electrical connection parameters of the electrodes dynamically. By switching between different connection states (connected to each other, connected to ground, isolated), the system obtains multiple capacitance measurements that reflect different environmental conditions. This parameter variation allows the detection algorithm to identify and compensate for water-induced changes versus object-induced changes
2Measurement precision
If the sensor uses multiple electrode connection states for detection, then detection accuracy in wet conditions improves, but the control complexity and measurement process time increase
Solution Approach 1:
The patent combines multiple electrode connection measurements into a unified detection process. By measuring capacitance under different connection states and combining these measurements through calculation (comparing changes in capacitance values), the system achieves accurate object detection while compensating for environmental factors. The controller integrates multiple measurement results to make a single determination, reducing the apparent 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 allows for reliable detection of objects even in wet conditions, enhancing the accuracy and reliability of operation determination by isolating object-induced capacitance changes from environmental and water-related influences.
Implementation Method 1
A user performs an operation by touching a portion corresponding to sensor body 501 with a finger. This operation causes a change in a capacitance formed between a conductor around the electrodes and each of first electrode 1 and second electrode 2.
Implementation Method 2
Depending on the result of detection by this electrostatic detection sensor, a predetermined operation can be effected.
Data Source
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AI summary
A sensor body of an electrostatic detection sensor includes a first electrode and a second electrode surrounding the first electrode. A controller is configured to obtain a first sensed intensity of the sensor body while where the first electrode is connected to the second electrode. The controller is configured to obtain a second sensed intensity of the first electrode while the second electrode is grounded. The controller is configured to obtain a third sensed intensity of the second electrode while the first electrode is grounded. The controller is configured to determine whether an object approaches the sensor body or not based on first to third calculation values obtained by calculating the respective changes of the first to third sensed intensities with respect to time.