Pressure Sensor Diaphragm Sticking Prevention via Surface Unevenness
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Solution Overview
Problem
Pressure sensors face issues with sticking between the ceiling portion and diaphragm, leading to reduced detection accuracy due to the size and mechanical strength of the pressure reference chamber components.
Innovation Solution
The pressure sensor design incorporates unevenness on the surfaces facing the pressure reference chamber, with recessed portions and a sealing layer to reduce sticking, and a lid portion that protrudes to minimize contact area, utilizing silicon and silicon-based materials for easy formation and sealing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the pressure reference chamber is made larger to improve pressure detection range, then the detection range is improved, but the ceiling portion bends and contacts the diaphragm causing sticking
Solution Approach 1:
The invention introduces unevenness at specific locations on the substrate surface and ceiling portion to create non-contact zones. This local modification prevents sticking in critical areas while maintaining the overall large size of the pressure reference chamber for extended detection range.
Solution Approach 2:
The unevenness features (recessed portions or protrusions) introduce curvature elements to otherwise flat surfaces. This curvature prevents uniform contact between the ceiling portion and diaphragm, eliminating sticking while preserving the chamber's large volume for broad pressure detection capability.
2Weight of moving object
If the ceiling portion is made thinner to reduce weight and improve flexibility, then weight is reduced, but sticking occurs more easily due to reduced mechanical strength
Solution Approach 1:
By creating localized unevenness features on the ceiling portion, the invention ensures that even thin, lightweight ceilings maintain adequate spacing from the diaphragm at critical contact zones. The unevenness compensates for reduced mechanical strength by preventing complete contact.
Solution Approach 2:
The unevenness is built into the ceiling portion structure during manufacturing, proactively preventing sticking before it can occur. This preliminary geometric modification ensures that thin, lightweight ceilings inherently resist sticking without requiring additional reinforcement.
3Reliability
If unevenness is formed on the substrate surface to prevent sticking, then sticking is reduced, but manufacturing complexity increases
Solution Approach 1:
The invention combines the formation of unevenness with existing manufacturing steps such as sacrificial layer removal or direct substrate processing. By integrating unevenness creation into established工艺流程, the solution prevents sticking while minimizing additional manufacturing complexity.
Solution Approach 2:
The unevenness is defined by simple geometric parameters (depth, diameter, spacing) that can be controlled through standard fabrication techniques. This parameter-based approach allows precise control of anti-sticking features without requiring complex manufacturing processes.
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 configuration effectively reduces sticking and enhances pressure detection accuracy by minimizing contact area and stress concentration, resulting in a more reliable pressure sensor.
Implementation Method 1
a piezo-resistance element is disposed in the diaphragm
Data Source
AI summary
A pressure sensor has a substrate having a diaphragm, a cavity portion that is positioned on one side of the diaphragm, and a ceiling portion that is disposed opposite to the diaphragm via the cavity portion, and unevenness is formed on a surface of the substrate facing the cavity portion. In addition, the unevenness has a plurality of recessed portions.