Magnetostrictive Sensor Detector Coil Integrated in Semiconductor Chip
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Solution Overview
Problem
Existing magnetostrictive position sensors have large detector coils that require significant space and input signals due to their size and electrical losses, limiting their sensitivity and increasing manufacturing complexity.
Innovation Solution
The detector coil is integrated into a semiconductor chip, allowing for a much smaller and more sensitive position sensor with a higher number of turns, and the entire unit is designed as a flat coil to approach the waveguide closely, with electrical biasing replacing macroscopic bias magnets for compactness and reduced complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the detector coil is made larger to increase the number of turns and improve signal detection, then the sensitivity is improved, but the device size and manufacturing complexity increase
Solution Approach 1:
The patent replaces the traditional mechanical wire-wound detector coil with a printed circuit board (PCB) based planar coil. This substitution allows the coil to be manufactured using standard PCB fabrication processes, significantly reducing manufacturing complexity while maintaining or improving the number of turns and signal detection sensitivity. The planar coil design integrates directly into the PCB structure, eliminating the need for separate coil winding and assembly operations.
Solution Approach 2:
The patent transitions from a three-dimensional wire-wound coil structure to a two-dimensional planar coil structure on the PCB. This dimensional change allows for increased number of turns within a smaller footprint area, improving sensitivity without proportionally increasing the overall device size. The planar configuration enables better integration with the PCB and surrounding components.
2Power
If the detector coil is made larger to compensate for electrical losses in longer conductive paths, then the signal strength is improved, but the device size increases
Solution Approach 1:
The PCB-based planar coil reduces electrical losses by providing shorter and more direct conductive paths compared to traditional wire-wound coils. The traces on the PCB offer lower resistance and better electrical connectivity, maintaining signal strength without requiring a larger coil area. The integrated design minimizes the length of conductive paths between the coil and evaluation circuit.
Solution Approach 2:
The patent merges the detector coil with the PCB structure, making them part of the same component. This integration eliminates separate connection paths and reduces the overall area required for the detector unit. The coil traces are fabricated directly on the PCB along with other circuit elements, creating a compact unified structure.
3Measurement precision
If macroscopic bias magnets are used to set the operating point, then the magnetic field control is achieved, but the device size and structural complexity increase
Solution Approach 1:
The patent replaces macroscopic permanent bias magnets with an electrical biasing system implemented through PCB traces. Current-carrying traces on the PCB generate the necessary magnetic field to set the operating point of the magnetostrictive waveguide. This electrical approach eliminates the need for mechanical magnet positioning and reduces structural complexity while maintaining precise magnetic field control.
Solution Approach 2:
The patent changes the method of magnetic field generation from permanent magnets to electromagnetic induction through current-carrying PCB traces. This parameter change allows for dynamic control of the bias field strength by adjusting the current, providing flexibility in setting the operating point without changing the physical structure or positioning of components.
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 design results in a compact, cost-effective detector unit with enhanced sensitivity and reduced size, capable of generating a strong signal with weak Δμr input, while minimizing exposure and electromagnetic interference.
Implementation Method 1
The mechanical-elastic density wave passing through a magnetoelastic element, e.g. the Villary tape, thus manifests itself in a voltage change ΔU, which can be tapped as a useful signal at the detector coil.
Implementation Method 2
as a so-called Villary detector, is arranged around a Villary tape which extends transversely, in particular at a 90° angle, from the waveguide and is connected to it, in particular mechanically fixed, e.g. welded, in such a way that the torsional pulse running in the waveguide is transformed in the Villary band into a longitudinal wave.
Implementation Method 3
Based on the Wiedemann effect, a current pulse fed into the waveguide generates a torsional pulse of a MEDW when superimposed on an external magnetic field directed laterally onto the magnetostrictive waveguide
Data Source
AI summary
To reduce the construction effort and also to make it smaller, the detector coil (6) is formed in the detector head (7) of a magnetostrictive position sensor (100) in a semiconductor chip (2), in which at the same time also the evaluation circuit (16) is formed and—if biased electrically and by means of direct current—also the then necessary separate bias coil (18).