Pressure Sensor With Suspended Membrane Decoupling Mounting Stress
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Solution Overview
Problem
Pressure sensors are sensitive to mechanical stress during mounting, which can be transmitted to the deformable membrane, affecting their accuracy and reliability.
Innovation Solution
A pressure sensor design where the deformable membrane is mechanically decoupled from the contact portion of the substrate using suspension elements and a cap with a processing circuit, allowing for reduced stress propagation and enhanced membrane protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the deformable membrane is directly attached to the first substrate for electrical connection, then the device complexity is reduced, but mechanical stress from mounting is transmitted to the membrane affecting measurement precision
Solution Approach 1:
The first substrate is divided into a contact portion and a support portion separated by suspension elements. The deformable membrane is attached only to the support portion, creating a mechanical decoupling that prevents stress transmission from the contact portion to the membrane while maintaining electrical connectivity through the substrate layers.
Solution Approach 2:
The suspension elements act as intermediary structures between the contact portion and support portion of the first substrate. These elements provide mechanical support and electrical connectivity while isolating the membrane from mounting stresses, serving as a mediator that allows controlled interaction between different functional regions.
2Speed
If the deformable membrane is directly exposed to the environment for pressure sensing, then the sensing response is direct, but the membrane is vulnerable to contamination and damage
Solution Approach 1:
The deformable membrane is nested within a protective cavity structure formed in the first substrate. The membrane is positioned within this enclosed space, allowing it to sense pressure through deflection while being physically protected from environmental contaminants and mechanical damage by the cavity walls and substrate structure.
Solution Approach 2:
The deformable membrane itself serves as a flexible thin film that encloses the cavity while maintaining pressure sensitivity. This thin film structure allows pressure transmission while providing a protective barrier, and the cavity configuration ensures the membrane remains protected during operation.
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 significantly reduces stress-induced errors, protecting the membrane and maintaining sensor accuracy by decoupling it from mechanical stress during mounting and operation.
Implementation Method 1
the deformable membrane as element sensitive to stress
Implementation Method 2
A deformation of the deformable membrane is converted by suitable sensing means into a signal
Data Source
AI summary
A pressure sensor comprises a first substrate and a cap attached to the first substrate. The cap includes a processing circuit, a cavity and a deformable membrane separating the cavity and a port open to an outside of the pressure sensor. Sensing means are provided for converting a response of the deformable membrane to pressure at the port into a signal capable of being processed by the processing circuit. The cap is attached to the first substrate such that the deformable membrane faces the first substrate and such that a gap is provided between the deformable membrane and the first substrate which gap contributes to the port. The first substrate comprises a support portion the cap is attached to, a contact portion for electrically connecting the pressure sensor to an external device, and one or more suspension elements for suspending the support portion from the contact portion.