Proximity Sensor Dual-Coil Design for Embedded Metal Interference
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Solution Overview
Problem
Proximity sensors fail to detect a weak change in reception waveforms due to the influence of embedded metals, limiting the detection distance.
Innovation Solution
The proximity sensor incorporates a first and second coil with the second coil disposed concentrically, a ferrite core, and a control circuit to detect changes in voltage or current, with direct bonding of coil wires to the substrate, and uses a magnetic and electric shield to suppress the influence of embedded metals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If the detection distance is extended to avoid contact with the detection object, then the sensor can operate at a safer distance, but the sensor cannot detect weak changes in reception waveform due to embedded metal interference
Solution Approach 1:
The coil is divided into two separate coils: a first coil for generating the magnetic field and a second coil for detecting changes in the reception waveform. This segmentation allows the detection coil to be positioned optimally for sensitivity while the generation coil provides the magnetic field, enabling weak signal detection at extended distances without embedded metal interference
Solution Approach 2:
The detection function is extracted from the coil generation system by using a separate second coil specifically for detecting reception waveform changes. This extraction allows the detection mechanism to operate independently and sensitively detect weak magnetic field changes even when embedded metals are present in the mounting 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
The solution enables the sensor to extend the detection distance by effectively reducing the impact of embedded metals, improving detection accuracy and range.
Implementation Method 1
The coil generates a magnetic field by an excitation current
Implementation Method 2
The ferrite core guides a magnetic field generated from the coil
Implementation Method 3
The reception circuit detects a voltage or a current generated in each of the first coil and the second coil by the magnetic field which is changed by the detection object
Data Source
AI summary
Provided is a proximity sensor capable of sufficiently extending a detection distance by suppressing an influence of embedded metal. A coil of a proximity sensor includes a first coil and a second coil. The second coil is disposed concentrically with the first coil. The proximity sensor detects a detection object on the basis of a change in voltage or current generated in each of the first coil and the second coil. The coil wire of the first coil is electrically connected to the in-head substrate through direct bonding.