Linear Capacitive Electrode Layout for Precise Object Position Detection
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Solution Overview
Problem
Electrostatic-capacitive proximity detecting devices face challenges in accurately determining the position of a to-be-detected object within a specific region due to the non-directive nature of the electric field, leading to difficulties in distinguishing objects at different locations based on equivalent electrostatic capacitance changes.
Innovation Solution
A linear arrangement of electrodes is used, where the electrodes are driven in a time division manner to detect electrostatic capacitances, and the position of the object is determined by analyzing the bias in detection values and spacing distances, allowing for high-accuracy positioning and region determination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single electrode is used for proximity detection, then the device structure is simple, but the position determination accuracy deteriorates because the electric field extends spherically and cannot provide directional information
Solution Approach 1:
The single electrode is segmented into multiple electrodes (first, second, third, and fourth electrodes) arranged in specific patterns. Each electrode detects electrostatic capacitance independently, and the combination of detection values from multiple electrodes enables accurate position determination through coordinate calculation, resolving the contradiction between structural simplicity and position accuracy.
Solution Approach 2:
The invention transitions from one-dimensional detection (single electrode) to two-dimensional detection by arranging electrodes in specific spatial patterns (e.g., corners of a rectangle). This dimensional expansion allows the system to determine both x and y coordinates of the object, providing directional information that was impossible with a single electrode while maintaining reasonable structural complexity.
2Measurement precision
If electrodes are arranged to improve position detection accuracy, then the measurement precision improves, but the device complexity increases due to more electrodes and complex driving circuits
Solution Approach 1:
The invention employs time-division multiplexing to drive multiple electrodes periodically and sequentially rather than simultaneously. Each electrode is driven in turn during different time intervals, allowing the use of multiple electrodes for improved position accuracy while avoiding the need for complex simultaneous driving circuits. The electrostatic capacitance detection unit measures capacitance values from each electrode during its active period, and the control unit processes these sequential measurements to calculate precise object coordinates.
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 enables precise detection of the object's position and accurate determination of its location within a specific region, enhancing the accuracy and reliability of the proximity detection.
Implementation Method 1
detect proximity of a to-be-detected object by utilizing an electric field that extends spherically from an electrode
Implementation Method 2
an electrostatic capacitance that occurs between an electrode and a to-be-detected object spaced from the electrode
Data Source
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AI summary
An electrostatic-capacitive proximity detecting device includes: an electrode unit including a plurality of electrodes linearly arranged along one direction; an electrostatic capacitance detector that drives the electrodes in a time division manner and detects detection values corresponding to electrostatic capacitances between a to-be-detected object and the respective electrodes; and a position detector that detects a position of the to-be-detected object in the direction, based on arrangement positions of the respective electrodes in the direction and a bias in magnitudes of the detection values detected for the respective electrodes by the electrostatic capacitance detector.