MEMS Microphone Blowout Resistance via Elastic Ventilation
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Solution Overview
Problem
MEMS microphones have a weak resistance to blowing due to the time it takes for air pressure in the front and back chambers to balance, which can damage the diaphragm and reduce their durability.
Innovation Solution
A MEMS microphone design featuring a substrate with a first and second acoustic hole, a connecting channel, and a ventilation hole, along with an elastic member to control the ventilation hole, which helps balance air pressure between the chambers and absorb external airflow impacts, enhancing blowout resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a through hole is provided in the substrate to communicate with the front chamber, then air pressure can be balanced between front and back chambers, but the diaphragm is damaged due to time delay in pressure balancing and the microphone has weak resistance to blowing
Solution Approach 1:
The substrate is divided into multiple functional regions with different hole configurations: the first acoustic hole provides pressure balance for the front chamber, while the second acoustic hole and ventilation hole provide pressure balance for the back chamber. This segmentation allows independent optimization of pressure balance timing and blowing resistance for each chamber, resolving the contradiction between achieving pressure balance and protecting the diaphragm from blowing damage.
2Measurement precision
If the MEMS Die divides the receiving cavity into front and back chambers, then acoustic performance is improved, but the diaphragm is vulnerable to blowing damage due to pressure imbalance
Solution Approach 1:
The elastic member acts as an intermediary element that mediates between the external environment and the back chamber. It provides a controlled ventilation path that opens under blowing conditions to equalize pressure, thereby protecting the diaphragm from direct exposure to strong airflow while maintaining the chamber division necessary for acoustic performance.
3Speed
If the ventilation hole is always open, then air pressure balances quickly, but external airflow directly impacts the diaphragm causing damage
Solution Approach 1:
The ventilation hole transitions from a static open state to a dynamic controlled state through the elastic member. The elastic member opens the ventilation hole when pressure imbalance occurs during blowing, allowing rapid pressure equalization, then closes it normally to block direct airflow impact on the diaphragm. This dynamic behavior resolves the contradiction between fast pressure balance and protecting against airflow damage.
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 improves the microphone's resistance to blowing by timely balancing air pressure and reducing the impact on the diaphragm, thereby increasing its durability and reliability.
Implementation Method 1
an elastic member covering the ventilation hole, the elastic member is used for opening or closing the ventilation hole
Data Source
AI summary
The present disclosure discloses a MEMS microphone including a shell, a substrate assembled with the shell for forming a receiving space, an ASIC Die, a MEMS Die including a diaphragm and a back plate, and an elastic member. The diaphragm divides the receiving space into a front chamber and a rear chamber, the substrate comprises a first acoustic hole, a second acoustic hole, a connecting channel, and a ventilation hole, the MEMS Die covers the first acoustic hole which is communicating with the front chamber, the ventilation hole is communicating with the connecting channel and the rear chamber, the elastic member covering the ventilation hole is used for opening or closing the ventilation hole. Compared with the related art, a MEMS microphone disclosed by the present disclosure could have with high blowout resistance.