Magnetic Sensor Nested Packaging for Air Gap Compensation
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Solution Overview
Problem
Existing magnetic field sensors packaged in a way that is not suitable for harsh environments, such as automobiles, suffer from a decrease in magnetic field strength due to an air gap, which affects their performance in detecting magnetic flux density.
Innovation Solution
A measuring system with a magnetic device featuring a combination of main and secondary magnetic poles, where the secondary poles can partially compensate the main magnetic field, reducing the magnetic flux density offset and enhancing the signal-to-offset ratio, is designed to improve the detection of magnetic field flux density in specific spatial directions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the sensor element is packaged in a protective package for harsh environments, then the reliability is improved, but the magnetic field strength decreases due to increased air gap
Solution Approach 1:
The magnetic sensor element is nested within an inner package that is itself nested within an outer protective package. This nested structure allows the sensor to be protected from harsh environments while minimizing the air gap distance, as the inner package serves as the immediate enclosure for the sensing element, reducing the effective air gap compared to a single-layer packaging approach.
2Strength
If the sensor element is placed closer to the magnet, then the magnetic field strength increases, but the protection from moisture and dirt decreases
Solution Approach 1:
The nested package structure enables the sensor element to be positioned close to the magnet within the inner package while the outer package provides the protective barrier. This resolves the contradiction by separating the functional requirement (close proximity for strong magnetic field) from the protective requirement (enclosure for harsh environment protection).
Solution Approach 2:
The inner package acts as an intermediary structure between the sensor element and the outer protective package. It allows the sensor to maintain close proximity to the magnet for optimal magnetic field detection while the outer package provides the necessary protection, effectively mediating between the conflicting requirements of close positioning and environmental protection.
3Reliability
If an additional protective package is added, then the reliability is improved, but the device complexity increases
Solution Approach 1:
The nested package design consolidates multiple protective functions into a hierarchical structure where the inner package protects the sensor element and the outer package provides additional environmental protection. This nested approach is more space-efficient and structurally integrated than separate stacked packages, reducing overall complexity while maintaining reliability.
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 increases the signal-to-offset ratio by reducing the magnetic flux density component, allowing for more accurate measurements, and is advantageous for use in harsh environments by integrating the magnetic device and sensor in a component package for mounting on a circuit substrate.
Implementation Method 1
The magnetic field in the magnetic field sensor can be formed by superposition of the main magnetic field and the secondary magnetic field
Implementation Method 2
a magnetic field sensor for detecting a flux density of the magnetic field at least in a first spatial direction
Data Source
AI summary
A measuring system having a magnetic device for generating a magnetic field and having a magnetic field sensor for detecting a flux density of the magnetic field at least in a first spatial direction, whereby the magnetic field sensor is fixedly positioned relative to the magnetic device. The magnetic device has at least two main poles for generating a main magnetic field and at least two secondary poles for generating a secondary magnetic field. The magnetic field in the magnetic field sensor is formed by superposition of the main magnetic field and the secondary magnetic field. The magnetic field sensor is designed to measure the flux density of the superposition in the first spatial direction, and, in the magnetic field sensor, the secondary magnetic field compensates at least partially the main magnetic field in the first spatial direction.