Pressure Sensor Chip Annular Grooves Stress Distribution

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Solution Overview

Problem

Existing pressure sensor chips face issues with stress concentration at the diaphragm edge due to excessive pressure, leading to reduced withstanding pressure and potential breakage, especially when peripheral portions are entirely bonded to the sensor diaphragm.

Innovation Solution

A pressure sensor chip design featuring first and second holding members bonded to the sensor diaphragm with non-bonding regions and annular grooves that distribute pressure and reduce stress concentration, allowing for increased withstanding pressure and preventing edge gaps.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If peripheral portions of holding members are entirely bonded to the sensor diaphragm, then bonding strength is improved, but stress concentration at the diaphragm edge occurs leading to reduced withstanding pressure

Engineering Contradiction:

Improvebonding strengthVSAvoidwithstanding pressure

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

The peripheral portion of the holding member is divided into a bonding region and a non-bonding region. The bonding region provides adequate bonding strength while the non-bonding region prevents stress concentration at the diaphragm edge, thus resolving the contradiction between bonding strength and withstanding pressure.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the holding member's peripheral portion are assigned different functions: the bonding region is designed for strong adhesion to the diaphragm, while the non-bonding region is designed to be free from bonding to reduce stress concentration. This local differentiation allows both bonding strength and withstanding pressure to be optimized.

Inventive Principle:

Principle #3Local quality

2Reliability

If annular grooves are added to the holding member, then stress distribution is improved, but device complexity increases

Engineering Contradiction:

Improvestress distributionVSAvoidstructure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The holding member is segmented into functional regions including bonding region, non-bonding region, and annular grooves. This segmentation creates distinct zones that collectively improve stress distribution while maintaining manufacturing feasibility.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The annular grooves modify the geometric parameters of the holding member, creating stress-relief features that redistribute mechanical loads. These parameter changes improve stress distribution without requiring fundamental redesign of the overall structure.

Inventive Principle:

Principle #35Parameter changes

3Reliability

If non-bonding region is created in the holding member, then stress concentration is reduced, but bonding area is decreased

Engineering Contradiction:

Improvestress concentrationVSAvoidbonding area

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The peripheral portion is segmented into bonding and non-bonding regions, allowing the bonding region to provide sufficient bonding area while the non-bonding region prevents stress concentration. The segmentation enables both requirements to be satisfied simultaneously.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Local quality differentiation between bonding and non-bonding regions allows the bonding region to maintain adequate bonding area while the non-bonding region locally eliminates stress concentration, resolving the contradiction between these two requirements.

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 effectively reduces stress concentration at the diaphragm edge, ensuring higher withstanding pressure and preventing damage from excessive pressure, while also allowing for size reduction of the chip.

Implementation Method 1

a resistance strain gauge is formed on a thin-plate diaphragm that is displaced upon receiving pressure, and the pressure applied to the diaphragm is detected from change in a resistance value of the resistance strain gauge formed on the diaphragm

Methodology Applied

Scientific EffectPiezoresistive effect: Piezoresistive Effect

Data Source

PatentUS10139301B2Pressure sensor chip including first and second annular shape grooves in a non-bonding region of a holding member for a sensor diaphragm

Publication Date: 2018.11.27 AZBIL CORP

AI summary

A pressure sensor chip that includes a sensor diaphragm; and a first holding member and a second holding member bonded respectively to first surface and the second surface of the sensor diaphragm with peripheral portions thereof being positioned to face each other, each of the first holding member and the second holding member has a pressure introduction hole, the first holding member includes a non-bonding region formed inside the first holding member and communicating with a periphery of the pressure introduction hole, first and second grooves each has an annular shape formed in a peripheral edge portion of the non-bonding region, an end of the second groove is positioned closer to the pressure introduction hole than an end of the first groove, and the second holding member includes a recess.