MEMS Microphone Dislocated Acoustic Hole and Adhesive Layer
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Solution Overview
Problem
Conventional MEMS microphones are prone to malfunction due to the entry of micro-particles through venting holes and acoustic holes, which can reduce diaphragm vibration and sensitivity.
Innovation Solution
The MEMS microphone design incorporates an adhesive layer surrounding the cavity with a dislocated acoustic hole, creating a gap that prevents direct connection between the acoustic hole and cavity, and optionally includes a trench channel to enhance acoustic source reception while minimizing particle entry.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the acoustic hole is directly connected to the cavity, then acoustic source reception is effective, but micro-particles can enter the chamber and cause malfunction
Solution Approach 1:
The patent introduces an adhesive layer as an intermediary component between the cavity and the external environment. This adhesive layer surrounds the cavity and creates a barrier that prevents micro-particles from directly entering the chamber through the acoustic hole, while still allowing acoustic waves to pass through effectively.
Solution Approach 2:
The patent segments the direct connection between the acoustic hole and the cavity by introducing the adhesive layer as a separate component. This segmentation creates a controlled interface that can selectively allow acoustic waves while blocking micro-particles, thus resolving the contradiction between particle resistance and acoustic reception.
2Stability of the object's composition
If venting holes are provided in the backplate, then acoustic pressure equalization is achieved, but micro-particles can pass through and enter the chamber
Solution Approach 1:
The adhesive layer acts as an intermediary that surrounds the cavity and prevents micro-particles from passing through the venting holes into the chamber. It creates a protective barrier that maintains acoustic pressure equalization functionality while blocking particle contamination.
Solution Approach 2:
The adhesive layer forms a thin film structure that conforms to the cavity geometry and provides a flexible yet effective barrier. This thin film prevents particle ingress while allowing the necessary acoustic pressure equalization through the venting holes.
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 significantly reduces the entry of micro-particles into the chamber, ensuring normal diaphragm vibration and sensitivity, while allowing effective acoustic source reception.
Implementation Method 1
an adhesive layer is disposed on the substrate, surrounding the cavity. A cover plate is adhered on the adhesive layer
Implementation Method 2
when the cavity 112 receive the acoustic source, the diaphragm 108 can sense the acoustic source and then vibrates
Implementation Method 3
The diaphragm 108 and the backplate 106 form a micro capacitor 104, having corresponding capacitance
Data Source
AI summary
A micro-electrical-mechanical system (MEMS) microphone includes a MEMS structure, having a substrate, a diaphragm, and a backplate, wherein the substrate has a cavity and the backplate is between the cavity and the diaphragm. The backplate has multiple venting holes, which are connected to the cavity and allows the cavity to extend to the diaphragm. Further, an adhesive layer is disposed on the substrate, surrounding the cavity. A cover plate is adhered on the adhesive layer, wherein the cover plate has an acoustic hole, dislocated from the cavity without direct connection.