Position Detection Device With Offset-Canceling Receiver Coil
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Solution Overview
Problem
Existing position detection devices suffer from reduced detection accuracy due to induced currents in the receiver coil, which cause offset in the output voltage waveform, exceeding the signal adjustment range of the signal processing unit.
Innovation Solution
The position detection device incorporates a receiver coil with multiple spiral portions, a connecting wire, and a parallel wire, arranged such that the magnetic fields generated by the currents in these components cancel each other out, preventing offset in the output voltage waveform.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a conventional receiver coil is used, then the device structure is simple, but the detection accuracy deteriorates due to offset in output voltage waveform
Solution Approach 1:
The receiver coil is divided into multiple spiral portions (first spiral portion, second spiral portion, etc.) that are arranged in specific patterns. Each spiral portion contributes to generating magnetic fields that cancel out offset-inducing fields, thereby improving detection accuracy while maintaining manageable structural complexity through modular segmentation.
Solution Approach 2:
Different portions of the receiver coil are designed with specific local characteristics - the spiral portions are positioned and oriented to generate magnetic fields that specifically counteract the offset caused by connecting wires. This local optimization of field cancellation ensures that each part of the coil contributes to eliminating the voltage waveform offset, improving overall measurement precision.
2Measurement precision
If spiral portions are added to the receiver coil, then detection accuracy improves, but the manufacturing complexity increases
Solution Approach 1:
The receiver coil employs spiral portions with curved geometries that follow specific patterns. These curved structures are designed to generate magnetic fields that cancel offset effects. The spiral configuration allows for systematic manufacturing using standard PCB winding or coil formation techniques, balancing the need for precise field cancellation with manufacturability.
3Measurement precision
If multiple spiral portions are used, then the output voltage waveform offset is reduced, but the device complexity increases
Solution Approach 1:
The spiral portions are arranged in an asymmetric pattern where the first spiral portion and second spiral portion are positioned at different locations and orientations relative to the connecting wires. This asymmetric arrangement is specifically designed to generate magnetic fields that effectively cancel the offset-inducing fields from the connecting wires, improving voltage waveform accuracy without requiring excessive symmetry that would increase 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 configuration enhances detection accuracy by maintaining the output voltage within the signal adjustment range of the signal processing unit, thereby improving the precision of position detection.
Implementation Method 1
The receiver coil has a plurality of spiral portions inductively coupled by electromagnetic induction caused by energization of the transmitter coil
Implementation Method 2
the magnetic fields generated by the currents in these components cancel each other out, preventing offset in the output voltage waveform
Data Source
AI summary
A position detection device for detecting a position of a displaceable detection object includes a substrate, a transmitter coil and a receiver coil. The substrate is disposed facing the detection object. The transmitter coil extends in a plane direction of the substrate. The receiver coil in which wiring is formed in a spiral shape and aligned in a direction of displacement of the detection object includes a plurality of spiral portions which are inductively coupled by electromagnetic induction caused by current passing through the transmitter coil, a connecting wire which electrically connect the plurality of spiral portions to each other, and a parallel wire which is electrically connected to the spiral portions and the connecting wire and extends parallel to the connecting wire.