Pressure Sensor Assembly Maintaining Magnetization

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Solution Overview

Problem

The manufacturing process of pressure sensing devices using magneto-resistive effect devices often results in reduced sensitivity due to stress applied during assembly, which causes changes in the magnetization direction of the magnetic layers, leading to deterioration of device characteristics.

Innovation Solution

The method involves preparing a sensor unit with a membrane body and an element unit including magnetic layers, and a mounting substrate with electrode pads, where the electrode pads are joined to the electrodes while heated under an external magnetic field aligned with the initial magnetization direction of the magnetic layers to maintain their orientation and prevent changes during assembly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the electrode pads are joined to the electrodes during assembly, then the device can be manufactured, but the stress applied during joining changes the magnetization direction of the magnetic layers and reduces sensitivity

Engineering Contradiction:

Improveassembly processVSAvoidsensitivity

Core Design Contradiction:

Ease of manufactureVSMeasurement precision

Solution Approach 1:

An external magnetic field is applied in the initial magnetization direction during the joining process to counteract the stress-induced magnetization changes. This preliminary anti-action prevents the harmful effect of stress on magnetic layer orientation, allowing assembly to proceed while maintaining sensitivity.

Inventive Principle:

Principle #9Preliminary anti-action

Solution Approach 2:

The magnetization direction parameter is maintained by applying an external magnetic field during assembly. This parameter change (applying external field) compensates for the stress-induced changes, ensuring the magnetic layers retain their initial magnetization orientation and the device maintains its sensitivity.

Inventive Principle:

Principle #35Parameter changes

2Ease of manufacture

If stress is applied to the magneto-resistive effect device during manufacturing processes, then the device can be assembled, but the sensitivity of the magneto-resistive effect device is reduced

Engineering Contradiction:

Improveassembly processVSAvoiddevice characteristics

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The external magnetic field applied during assembly serves as a preliminary anti-action that counteracts the stress-induced changes in magnetization direction. This prevents deterioration of device characteristics while allowing necessary assembly operations to proceed.

Inventive Principle:

Principle #9Preliminary anti-action

Solution Approach 2:

The stress applied during assembly, which would normally be harmful to magnetic layer orientation, is counteracted by the external magnetic field. The harmful stress effect is converted into a controlled process where the external field maintains magnetization direction while the stress facilitates assembly operations.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Ease of manufacture

If the magnetization direction of magnetic layers is changed during assembly, then the device can be manufactured, but the sensitivity and reliability of the pressure sensing device deteriorate

Engineering Contradiction:

Improveassembly processVSAvoidsensitivity

Core Design Contradiction:

Ease of manufactureVSMeasurement precision

Solution Approach 1:

The magnetization direction parameter is actively maintained during assembly by applying an external magnetic field in the initial magnetization direction. This parameter control ensures that despite stress during assembly, the magnetic layers retain their correct magnetization orientation and the device maintains high sensitivity.

Inventive Principle:

Principle #35Parameter changes

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

This approach suppresses the deterioration of sensor unit characteristics, enabling the production of highly sensitive pressure sensing devices with improved reliability and stability by maintaining the initial magnetization direction of the magnetic layers.

Implementation Method 1

with an external magnetic field along the first direction applied to the sensor unit

Methodology Applied

Scientific EffectMagnetic field: Magnetic Field

Implementation Method 2

joining the first electrode pad to the first electrode while heated, and joining the second electrode pad to the second electrode while heated

Methodology Applied

Scientific EffectHeating: Heating

Data Source

PatentUS9046549B2Method for manufacturing pressure sensing device

Publication Date: 2015.06.02 KK TOSHIBA

AI summary

According to one embodiment, a method for manufacturing a pressure sensing device includes preparing a sensor unit and a mounting substrate. The sensor unit includes: a membrane body; and an element unit provided on the membrane body. The element unit includes: a first electrode; a second electrode; and a first magnetic layer provided between the first electrode and the second electrode and having magnetization in a first direction. The mounting substrate includes: a base; a first electrode pad provided on the base; and a second electrode pad provided on the base and provided apart from the first electrode pad. The method further includes joining the first electrode pad to the first electrode while heated, and joining the second electrode pad to the second electrode while heated, with an external magnetic field along the first direction applied to the sensor unit.