Encapsulated Magnetoresistive Sensor Layout for Harsh Environments

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Solution Overview

Problem

Existing magnetic sensors face challenges in maintaining high environmental tolerance in rigorous environments, such as high temperatures and exposure to oil and chemical substances, which can damage the anisotropic magnetoresistive layer.

Innovation Solution

A magnetic sensor design that includes an insulating substrate with magnetoresistive elements and conductors encapsulated by an encapsulant, where the insulating substrate is arranged in a facedown configuration to expose the second surface and conductor ends, providing protection and improved environmental tolerance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the anisotropic magnetoresistive layer is protected by a protective coating, then the sensor can operate in rigorous environments, but the environmental tolerance is still insufficient for extreme conditions

Engineering Contradiction:

Improveenvironmental toleranceVSAvoiddamage from high temperature and chemical substances

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent implements a nested protection structure where the magnetoresistive element is first covered by a protective coating, then the entire insulating substrate containing the magnetoresistive element is encapsulated by an encapsulant. This multi-layer nested structure provides progressive protection against high temperatures and chemical substances, enabling the sensor to operate in extreme environments where single-layer protection would fail.

Inventive Principle:

Principle #7Nested doll (Nesting)

Solution Approach 2:

The patent combines different protective materials with complementary properties: a protective coating material that provides baseline protection and an encapsulant material that adds enhanced thermal and chemical resistance. This composite protection system leverages the strengths of different materials to achieve superior environmental tolerance that neither material could provide alone.

Inventive Principle:

Principle #40Composite materials

2Reliability

If the insulating substrate is made of alumina, then the magnetoresistive element is protected, but the sensor structure lacks optimal protection configuration

Engineering Contradiction:

Improveprotection of magnetoresistive elementVSAvoidprotection structure configuration

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent inverts the conventional protection configuration by placing the magnetoresistive element on the first surface of the insulating substrate and exposing the second surface, rather than covering the entire substrate. This inverted configuration allows the magnetoresistive element to be protected by the substrate itself while the encapsulant provides additional protection from the exposed second surface, creating an optimized protection hierarchy that reduces unnecessary material usage.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The patent applies protection selectively: the insulating substrate provides protection for the magnetoresistive element on its first surface, while the encapsulant specifically protects the exposed second surface and surrounding areas. This local quality approach ensures that protection is applied where needed without adding unnecessary complexity to areas already adequately protected.

Inventive Principle:

Principle #3Local quality

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 design enhances the sensor's ability to operate accurately in harsh conditions by protecting the magnetoresistive elements and improving detection accuracy while withstanding extreme temperatures and chemical exposure.

Implementation Method 1

The magnetoresistive element includes a magnetoresistive film and an electrode. The magnetoresistive film is formed on a first surface of the insulating substrate.

Methodology Applied

Scientific EffectMagnetoresistance: Magnetoresistance

Data Source

PatentUS12504485B2Magnetic sensor

Publication Date: 2025.12.23 PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO LTD

AI summary

A magnetic sensor includes an insulating substrate, at least one magnetoresistive element, a conductor, and an encapsulant. The conductor electrically connects the magnetoresistive element to an external circuit. The encapsulant encapsulates not only the magnetoresistive element entirely but also the insulating substrate and the conductor at least partially. The magnetoresistive element includes a magnetoresistive film and an electrode. The magnetoresistive film is formed on a first surface of the insulating substrate. The electrode is provided on the first surface of the insulating substrate. One end of the electrode is electrically connected to the magnetoresistive film. The other end of the electrode is electrically connected to a first end portion of the conductor. The encapsulant exposes a second surface of the insulating substrate and a second end portion of the conductor from mutually different surfaces.