Magnetoresistive Multi-Turn Sensor Coil With Trench-Bridge Spiral Connection
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Solution Overview
Problem
Magnetic multi-turn sensors face challenges in fabricating closed loop configurations due to the thin magnetoresistive film, which makes it difficult to connect inner and outer spirals without disrupting domain walls and causing errors in turn count.
Innovation Solution
A continuous coil of magnetoresistive elements is formed on a substrate with a trench and bridge arrangement, allowing the inner and outer spirals to be connected without interfering with the magnetoresistive elements, enabling accurate turn counting with minimal power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a closed loop configuration is used to enable high turn counting, then the number of turns that can be counted increases, but the thin magnetoresistive film makes it difficult to connect inner and outer spirals without disrupting domain walls
Solution Approach 1:
The substrate is segmented into distinct regions including trenches and bridges, separating the connection function from the sensing function. This allows the magnetoresistive film to be continuous for accurate turn counting while the substrate structure provides stable support that prevents domain wall disruption at connection points
Solution Approach 2:
The substrate with its trench and bridge structure acts as an intermediary between the inner and outer spirals. The bridge region provides a stable intermediate platform that connects the spirals without requiring the magnetoresistive film to cross over other spiral windings, thus preventing domain wall disruption while enabling continuous coil configuration for high turn counting
2Volume of moving object
If the magnetoresistive film is made thinner to reduce size, then the sensor compactness improves, but connecting inner and outer spirals becomes more difficult without causing errors
Solution Approach 1:
The connection between inner and outer spirals is achieved by transitioning to another dimension through the substrate's vertical structure (trenches and bridges). This allows the thin magnetoresistive film to connect spirals via the substrate's three-dimensional structure rather than requiring the film to bridge large horizontal gaps, making manufacturing feasible while maintaining compact size
3Measurement precision
If a continuous coil configuration is implemented to enable accurate turn counting, then measurement accuracy improves, but the fabrication complexity increases due to the need for trench and bridge structures
Solution Approach 1:
The substrate with trench and bridge structures serves multiple functions simultaneously: it provides mechanical support for the thin magnetoresistive film, enables continuous coil configuration for accurate turn counting, prevents domain wall disruption, and facilitates spiral connections. This multi-functionality reduces the need for additional separate components, thereby managing fabrication complexity while achieving high measurement precision
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 allows for precise measurement of a large number of turns in an external magnetic field without power, utilizing the non-volatile magnetic domain position to ensure accurate turn counting.
Implementation Method 1
Magnetic multi-turn sensors typically include magnetoresistance elements that are sensitive to an applied external magnetic field. The resistance of the magnetoresistance elements can be changed by rotating a magnetic field within the vicinity of the sensor.
Implementation Method 2
The solution allows for precise measurement of a large number of turns in an external magnetic field without power, utilizing the non-volatile magnetic domain position to ensure accurate turn counting.
Data Source
AI summary
The present disclosure provides a magnetic multi-turn sensor comprising a continuous coil of magnetoresistive elements and a method of manufacturing said sensor. The continuous coil is formed on a substrate such as a silicon wafer that has been fabricated so as to form a trench and bridge arrangement that enables the inner and outer spiral to be connected without interfering with the magnetoresistive elements of the spiral winding in between. Once the substrate has been fabricated with the trench and bridge arrangement, a film of the magnetoresistive material can be deposited to form a continuous coil on the surface of the substrate, wherein a portion of the coil is formed in the trench and a portion of the coil is formed on the bridge.