Curved Protruding Magnetic Sensor Structure to Prevent Cracking

Solution Overview

Problem

Magnetic sensors with sensor elements on inclined surfaces are prone to cracking due to discontinuities at the boundaries between protruding and flat portions, leading to potential structural failures during manufacturing or use.

Innovation Solution

The sensor design incorporates a support member with a protruding surface featuring continuous first and second curved surface portions, which reduces the likelihood of cracks by smoothing the transition from the substrate to the inclined surface where sensor elements are formed.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If sensor elements are formed on inclined surfaces of protruding portions, then the sensor can detect magnetic fields in the perpendicular direction, but cracks are generated in the support member near the boundary between protruding portions and flat portion

Engineering Contradiction:

Improvemagnetic field detection capabilityVSAvoidstructural integrity

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The invention replaces the trapezoidal protruding portions with cylindrical protruding portions that have curved surfaces. This curvature eliminates the sharp boundaries between inclined and flat surfaces, preventing stress concentration and crack generation while maintaining the inclined surface necessary for perpendicular magnetic field detection

Inventive Principle:

Principle #14Spheroidality (Curvature)

Solution Approach 2:

The invention changes the geometric parameters of the protruding portions from trapezoidal to cylindrical shapes. This parameter change transforms the surface geometry to eliminate discontinuities at boundaries, thereby preventing cracks while preserving the functional inclined surfaces for sensor operation

Inventive Principle:

Principle #35Parameter changes

2Measurement precision

If trapezoidal protruding portions are used to form inclined surfaces, then sensor elements can be positioned for perpendicular field detection, but the surface becomes discontinuous at boundaries

Engineering Contradiction:

Improvemagnetic field detection capabilityVSAvoidsurface continuity

Core Design Contradiction:

Measurement precisionVSShape

Solution Approach 1:

The invention replaces the trapezoidal protruding portions with cylindrical protruding portions that have curved surfaces. This curvature eliminates the sharp boundaries between inclined and flat surfaces, preventing stress concentration and crack generation while maintaining the inclined surface necessary for perpendicular magnetic field detection

Inventive Principle:

Principle #14Spheroidality (Curvature)

Solution Approach 2:

The invention changes the geometric parameters of the protruding portions from trapezoidal to cylindrical shapes. This parameter change transforms the surface geometry to eliminate discontinuities at boundaries, thereby preventing cracks while preserving the functional inclined surfaces for sensor operation

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS12498433B2Sensor

Publication Date: 2025.12.16 TDK CORP

AI summary

A magnetic sensor includes an insulating layer including a protruding surface, a first MR element, and a second MR element. The first MR element is disposed on a first inclined surface of the protruding surface. The second MR element is disposed on a second inclined surface of the protruding surface. The protruding surface includes first to third curved surface portions. Each of the second and third curved surface portions is a curved surface protruding in a direction closer to the top surface of the substrate.