MEMS Package Structure With Turbulent Acoustic Pressure Relief
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Solution Overview
Problem
The existing MEMS package structures are prone to diaphragm rupture due to direct airflow impact, and they exhibit weak resistance to blowing pressure.
Innovation Solution
A MEMS package structure with a circuit board featuring non-overlapping acoustic holes and protruding structures in the communication channel that cause airflow turbulence, reducing the pressure of airflow reaching the diaphragm by ½-⅔ compared to direct impact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the circuit board is provided with a through-hole connected to the front cavity allowing direct airflow, then the acoustic performance is improved, but the diaphragm becomes prone to rupture due to direct airflow impact
Solution Approach 1:
The patent introduces a communication channel with protruding structures as an intermediary between the first acoustic hole and second acoustic hole. This mediator creates turbulence and pressure reduction, allowing acoustic performance while protecting the diaphragm from direct high-pressure airflow impact.
Solution Approach 2:
The patent divides the single through-hole into two separate acoustic holes (first and second) connected by a communication channel. This segmentation allows the airflow path to be divided and controlled, with the communication channel providing turbulence and pressure reduction while maintaining acoustic functionality.
2Speed
If airflow enters directly through the through-hole to the diaphragm, then the acoustic response is fast, but the resistance to blowing pressure is weak
Solution Approach 1:
The patent uses protruding structures in the communication channel that create dynamic turbulence in the airflow. This dynamic flow control reduces pressure while maintaining response speed, as the turbulence dissipates energy without completely blocking the acoustic path.
3Reliability
If protruding structures are added to create turbulence and reduce pressure, then the anti-airblowing capability is enhanced, but the device complexity increases
Solution Approach 1:
The patent applies protruding structures only in the communication channel where they are most effective, rather than throughout the entire device. This localized application provides the necessary turbulence and pressure reduction while minimizing overall structural complexity.
Solution Approach 2:
The protruding structures are integrated within the communication channel, which itself is part of the circuit board structure. This nesting approach embeds the complexity within existing structures rather than adding separate components, reducing overall device complexity.
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 structure enhances the anti-airblowing capability by effectively reducing airflow pressure on the diaphragm, improving the reliability and durability of the MEMS package.
Implementation Method 1
A plurality of protruding structures are provided in the communication channel. The protruding structures cause a pressure of an airflow entering from the first acoustic hole to be 2-3.5 times the pressure of the airflow exiting from the second acoustic hole.
Data Source
AI summary
The present invention provides a MEMS package structure including a housing, a circuit board, a MEMS chip and an ASIC chip. The MEMS chip includes a diaphragm. The circuit board includes an upper and a lower surface. The circuit board includes a first acoustic hole extending from the lower surface, a second acoustic hole extending from the upper surface, and a communication channel. A projection of the first acoustic hole and a projection of the second acoustic hole along a vibration direction of the diaphragm are non-overlapped with each other. Some protruding structures are located in communication channel. The protruding structures cause a pressure of an airflow entering from the first acoustic hole to be 2-3.5 times the pressure of the airflow exiting from the second acoustic hole. The MEMS package structure of present invention has a stronger ability of anti-air-blowing.