Segmented Magnet Structure for Back-Biased Sensor Misalignment
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Solution Overview
Problem
Existing magnetic field sensors with back-biased magnet structures suffer from performance degradation due to positional misalignment between the magnet and the sensing elements, limiting their sensitivity, dynamic range, and assembly flexibility.
Innovation Solution
A magnet structure with a layered design, comprising alternating magnetic and non-magnetic layers, is introduced. This design allows for adjustable dimensions to accommodate different spacings between split MR structures, providing a robust back bias magnetic field while being immune to certain misalignments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a back-biased magnet structure is used in magnetic field sensors, then the sensor can provide bias magnetic field for sensing elements, but the sensor performance degrades due to positional misalignment between magnet and sensing elements
Solution Approach 1:
The magnet structure is divided into multiple magnetic segments separated by non-magnetic material layers. This segmentation creates multiple localized magnetic fields that collectively provide robust bias to the sensing elements, reducing sensitivity to misalignment between the magnet assembly and the IC die.
Solution Approach 2:
The magnet structure uses composite construction with alternating magnetic and non-magnetic material layers. This composite design allows the magnetic fields from different segments to combine effectively while the non-magnetic layers provide spacing and field distribution, maintaining performance despite positional variations.
2Ease of manufacture
If magnet and IC die are assembled outside factory setting, then assembly flexibility is improved, but misalignment between magnet and sensing elements increases
Solution Approach 1:
The segmented magnet design with multiple independent magnetic segments allows each segment to provide localized bias field coverage. This reduces the impact of misalignment when assembled outside factory settings, as the distributed magnetic fields ensure adequate bias across the sensing elements even with positional variations.
Solution Approach 2:
The magnet structure parameters (segment dimensions, spacing, thickness) are optimized to provide robust bias fields that are tolerant to misalignment. By adjusting these parameters, the design achieves immunity to certain misalignments while maintaining ease of assembly outside factory environments.
3Ease of manufacture
If magnet dimension is fixed, then manufacturing is simplified, but the magnet cannot accommodate different spacings between split MR structure
Solution Approach 1:
The magnet is divided into multiple segments with adjustable spacing controlled by non-magnetic material layers. This allows the overall magnet structure to be adapted to different spacings between split MR structures while maintaining a standardized manufacturing process for each segment.
Solution Approach 2:
The magnet structure is designed with adjustable parameters including segment spacing and thickness, allowing it to be configured for different applications with varying spacings between MR structures. This dynamic adaptability is achieved while keeping individual segment manufacturing standardized.
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 magnet structure effectively maintains sensor performance across various misalignment conditions, enabling flexible assembly outside of a factory setting and accommodating different IC package geometries, thus enhancing the reliability and cost-effectiveness of magnetic field sensors.
Implementation Method 1
a magnet structure to provide a bias magnetic field about the one or more magnetic field sensing elements
Implementation Method 2
one or more magnetoresistance (MR) elements
Data Source
AI summary
According to an embodiment, a magnetic field sensor includes: one or more magnetic field sensing elements; and a magnet structure to provide a bias magnetic field about the one or more magnetic field sensing elements, the magnet structure includes alternating magnetic layers and non-magnetic layers with at least three magnetic layers.