MEMS Acoustic Sensor Interior Flexible Member Design
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Solution Overview
Problem
Conventional spring-based acoustic sensors with perimeter springs coupled to the diaphragm face issues with modularity and microphone sensitivity due to non-flat diaphragm displacement, restricting the formation of sensor arrays and reducing performance.
Innovation Solution
Incorporating flexible members between the diaphragm and backplate, which are not located at the periphery, allowing for variable capacitance changes in response to sound pressure, enabling more flexible array configurations and improved sensitivity through adjustable gap creation between the diaphragm and backplate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If perimeter springs are coupled to the diaphragm, then the acoustic sensor can be formed, but the modularity is reduced and array formation is restricted
Solution Approach 1:
The flexible member is extracted from the peripheral location and repositioned to an interior location on the diaphragm. This extraction resolves the coupling between spring characteristics and diaphragm parameters, enabling independent optimization of each component and improving modularity for array formation.
Solution Approach 2:
The flexible member is positioned in the interior region of the diaphragm rather than at the periphery, changing the spatial dimension of its location. This dimensional repositioning allows for decoupling of design parameters and facilitates modular array configurations.
2Measurement precision
If perimeter springs are coupled to the diaphragm, then the acoustic sensor can be formed, but microphone sensitivity decreases due to non-flat diaphragm displacement
Solution Approach 1:
By extracting the flexible member from the periphery and placing it in the interior, the patent eliminates the constraint that causes non-flat diaphragm displacement. This allows the diaphragm to maintain a flatter displacement profile during operation, improving microphone sensitivity.
Solution Approach 2:
The flexible member is positioned at a specific interior location on the diaphragm rather than distributed at the periphery. This localized positioning provides targeted support that maintains diaphragm flatness while allowing optimal vibration characteristics for sensitivity.
3Adaptability or versatility
If flexible members are positioned at the interior of the diaphragm, then modularity is enhanced, but the gap control between diaphragm and backplate becomes more complex
Solution Approach 1:
A spacer is introduced as an intermediary element between the flexible member and the backplate to precisely control the gap distance. This mediator simplifies the overall design by providing a straightforward mechanical means for gap control while maintaining the benefits of interior flexible member positioning.
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 design enhances the modularity of acoustic sensor arrays and maintains or improves sensitivity by allowing flexible displacement of the diaphragm relative to the backplate, facilitating closer packing and efficient sound pressure conversion.
Implementation Method 1
allowing for variable capacitance changes in response to sound pressure
Implementation Method 2
facilitating efficient sound pressure conversion
Implementation Method 3
flexible member...allowing for variable capacitance changes...flexible displacement of the diaphragm
Data Source
AI summary
A micro electro-mechanical system (MEMS) acoustic sensor is disclosed. The acoustic sensor comprises a backplate and a diaphragm. The acoustic sensor further comprises a flexible member and optional spacer member disposed between the backplate and the diaphragm resulting in a gap between the backplate and the diaphragm. The gap can vary in response to impinging pressure on the diaphragm based on the design of the flexible member and resulting in a variable capacitance between the backplate and the diaphragm. The change in the gap can result in a change in an electrical characteristic associated with the variable capacitance and can be converted to an electrical output signal corresponding to the impinging pressure on the diaphragm. The flexible member can be part of the backplate or diaphragm.