Sloped-Substrate MR Sensor Layout for 3D Magnetic Field Sensing
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Solution Overview
Problem
Existing magnetic field sensors lack effective 3D sensing capabilities and are not adequately immune to in-plane and out-of-plane magnetic fields, limiting their sensitivity and accuracy in detecting magnetic field orientations.
Innovation Solution
Magnetic field sensors are designed with magnetoresistive (MR) sensing elements placed on sloped surfaces of a substrate, forming bridge configurations that provide sensitivity in multiple axes, including x, y, and z, and utilizing tunnelling magnetoresistive (TMR) elements and Hall elements to enhance sensitivity and immunity to specific field orientations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If magnetic field sensing elements are placed on sloped surfaces to achieve 3D sensing capability, then sensitivity to magnetic fields in multiple orientations is improved, but device complexity increases
Solution Approach 1:
The patent transitions from conventional planar sensor layouts to a three-dimensional configuration by placing magnetoresistive sensing elements on sloped surfaces at different heights and orientations. This dimensional change enables the sensor to detect magnetic fields in multiple orientations (in-plane and out-of-plane) simultaneously, achieving 3D sensing capability without requiring multiple separate sensor chips.
Solution Approach 2:
The sensor is divided into multiple magnetoresistive bridge elements positioned at different locations on the sloped substrate surfaces. Each element or group of elements is configured with specific reference layer orientations to provide sensitivity to particular field directions. This segmentation allows the complex 3D sensing function to be distributed across multiple simpler sensing units, each optimized for specific detection tasks.
2Measurement precision
If magnetoresistive sensing elements with specific reference layer orientations are used to provide immunity to in-plane fields, then measurement precision for out-of-plane fields is improved, but manufacturing precision requirements increase
Solution Approach 1:
Different regions of the sensor substrate are given different local qualities through the placement of magnetoresistive elements with specific reference layer orientations at different locations on the sloped surfaces. Each local region is optimized for detecting magnetic fields in specific directions, allowing the sensor to achieve both in-plane immunity and out-of-plane sensitivity through localized optimization rather than uniform design.
3Measurement precision
If sensing elements are positioned at different depths on the substrate to detect field gradients, then measurement precision for field gradient detection is improved, but device complexity increases
Solution Approach 1:
The patent utilizes the vertical dimension by positioning magnetoresistive sensing elements at different depths on the substrate through the sloped surface configuration. This depth variation creates a three-dimensional sensing array that can detect changes in magnetic field strength and direction across different z-heights, enabling field gradient detection without requiring additional specialized sensor layers.
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 a 3D magnetometer with improved sensitivity and immunity to in-plane and out-of-plane fields, allowing for precise detection of magnetic field gradients and orientations, enhancing the accuracy of magnetic field sensors in various applications.
Implementation Method 1
magnetoresistive (MR) magnetic field sensing elements
Implementation Method 2
tunnelling magnetoresistive (TMR) elements
Implementation Method 3
Hall elements deposited on at least one of the sloped surfaces
Data Source
AI summary
Methods and apparatus for a magnetic sensor having a substrate with a major surface and opposing sloped surfaces and magnetoresistive (MR) magnetic field sensing elements coupled in a bridge configuration. At least some of the magnetic field sensing elements are located on the sloped surfaces. In embodiments, the sensor comprises a 3D magnetometer. In some embodiments, the bridge configuration comprises an x-axis bridge, a y-axis bridge, and a z-axis bridge.