Capacitive Proximity Sensor With Switchable Electrodes for Directivity
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Solution Overview
Problem
Conventional capacitive proximity sensors face difficulties in improving directivity and maintaining flexibility due to their three-dimensional structure, which limits their ability to sense targets at varying distances and orientations effectively.
Innovation Solution
The capacitive proximity sensor employs a sensor electrode, an auxiliary electrode, a detection circuit, and a change-over switch to selectively connect or disconnect the electrodes from the detection circuit, allowing for comparison of capacitance values in different configurations to determine the presence and distance of a target within a defined sense region, thereby enhancing directivity and flexibility without a three-dimensional structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a three-dimensional shield electrode structure is used to improve directivity, then the directivity is improved, but the device complexity and size increase, reducing arrangement flexibility
Solution Approach 1:
The shield electrode is divided into multiple independent segments arranged in specific patterns (e.g., alternating polarities or selective grounding) rather than using a continuous three-dimensional structure. This segmentation maintains the directivity function while reducing overall structural complexity and size.
Solution Approach 2:
The patent transitions from a three-dimensional shield electrode structure to a two-dimensional planar arrangement of segmented electrodes. This dimensional reduction simplifies the overall structure while preserving the ability to control electric field distribution and achieve directivity through strategic electrode placement and connectivity control.
2Measurement precision
If a three-dimensional shield electrode structure is used to improve directivity, then the directivity is improved, but the device size increases, reducing arrangement flexibility
Solution Approach 1:
The shield electrode is divided into multiple independent segments arranged in specific patterns (e.g., alternating polarities or selective grounding) rather than using a continuous three-dimensional structure. This segmentation maintains the directivity function while reducing overall structural complexity and size.
Solution Approach 2:
The patent transitions from a three-dimensional shield electrode structure to a two-dimensional planar arrangement of segmented electrodes. This dimensional reduction simplifies the overall structure while preserving the ability to control electric field distribution and achieve directivity through strategic electrode placement and connectivity control.
3Adaptability or versatility
If the sensor structure is simplified to maintain flexibility, then the arrangement flexibility is improved, but the directivity deteriorates
Solution Approach 1:
The patent introduces switchable connectivity between sensor electrode segments and shield electrode segments, allowing the sensing system to dynamically adjust its configuration. This dynamic control enables the system to optimize directivity for different detection scenarios while maintaining overall structural simplicity and arrangement flexibility.
Solution Approach 2:
The patent changes the electrical parameters (connectivity state, potential distribution) of the segmented electrodes rather than relying on fixed three-dimensional structural complexity. By controlling which segments are connected or disconnected, the system achieves variable directivity performance while maintaining a simple, flexible physical structure.
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 configuration allows for reliable sensing of targets at arbitrary ranges with improved directivity and flexibility, enabling effective detection under various conditions without the limitations of a three-dimensional structure.
Implementation Method 1
a sensor electrode; a detection circuit connected at least to the sensor electrode and operative to detect a capacitance value based on a capacitance on the connected electrode
Implementation Method 2
an auxiliary electrode arranged in the vicinity of the sensor electrode; a change-over switch capable of selectively switching between a first connection state of not connecting the auxiliary electrode to the detection circuit and a second connection state of connecting the auxiliary electrode to the detection circuit
Data Source
AI summary
A capacitive proximity sensor (100) comprises a sensor unit (10) and a sense circuit unit (20). The sensor unit (10) includes a sensor electrode (11), a shield electrode (12) and an auxiliary electrode (13). The sensor electrode (11) is connected to a C-V conversion circuit (21) and the shield electrode (12) is connected to a shield drive circuit (24). The auxiliary electrode (13) is connected via a change-over switch (30) to the C-V conversion circuit (21) or the shield drive circuit (24). The capacitance values (C1, C2) switched by the change-over switch (30) and detected at the C-V conversion circuit (21) are compared to arbitrarily set a range of a sense region on the sensor electrode (11).