Optical Microphone Diaphragm Limiting Member Design
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Solution Overview
Problem
Conventional optical microphones face damage due to excessive diaphragm vibration displacement under high sound pressure, leading to stress and potential damage.
Innovation Solution
A microphone chip design featuring a diaphragm with limiting members on either side to restrict amplitude, comprising a base, diaphragm inner and outer parts, and a connection part with varying stiffness, along with a fixing member to support the diaphragm and limit excessive movement, reducing the risk of damage from high sound pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the diaphragm is allowed to vibrate freely under high sound pressure, then the sensitivity and detection range of the microphone is improved, but the diaphragm may be deflected greatly causing excessive stress and damage
Solution Approach 1:
The limiting member is pre-positioned at a predetermined location to counteract the potential excessive deflection of the diaphragm before it occurs. When the diaphragm vibrates under sound pressure, the limiting member prevents it from moving beyond the safe displacement threshold, thereby protecting the diaphragm from stress-induced damage while allowing normal vibration for signal detection.
Solution Approach 2:
The limiting member acts as an intermediary element between the diaphragm and the potential damage state. It is spaced apart from the diaphragm in the normal state but engages when the diaphragm approaches the dangerous displacement limit, serving as a protective mediator that transfers excess energy away from the diaphragm structure.
2Reliability
If the limiting member is positioned close to the diaphragm to effectively limit amplitude, then the protection against excessive vibration is improved, but the mechanical sensitivity of the diaphragm may be reduced
Solution Approach 1:
The limiting member is positioned to provide partial limitation of the diaphragm amplitude - not completely restricting the vibration but only limiting the excessive portions that would cause damage. The predetermined spacing allows normal vibration amplitude to pass through while only engaging when displacement exceeds the safe threshold, achieving partial protection without excessive constraint.
Solution Approach 2:
The design changes the spatial parameter (spacing distance) between the limiting member and diaphragm to optimize the balance between protection and sensitivity. By carefully controlling this distance, the system allows sufficient vibration amplitude for maintaining mechanical sensitivity while ensuring the limiting member engages before damage occurs.
3Strength
If the diaphragm is made more rigid to withstand high sound pressure, then the strength and damage resistance are improved, but the mechanical sensitivity and vibration response may be reduced
Solution Approach 1:
The diaphragm system is segmented into two functional parts: the diaphragm itself optimized for sensitivity and vibration response, and the limiting member providing protective strength. This segmentation allows each component to be optimized independently - the diaphragm remains compliant for high sensitivity while the limiting member provides the necessary strength protection against excessive pressure.
Solution Approach 2:
The limiting member provides beforehand cushioning protection by being pre-positioned to intercept excessive diaphragm deflection before it causes damage. This protective cushioning allows the diaphragm to be designed with higher sensitivity (lower rigidity) since the limiting member will prevent any potential damage from high sound pressure events.
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 effectively limits diaphragm amplitude, reducing the risk of damage while maintaining high mechanical sensitivity and allowing for a wider range of sound signal detection, thereby enhancing the durability and performance of optical microphones.
Implementation Method 1
The optoelectronic module converts the signal of the intensity and the phase of the reflected light into an electrical signal
Implementation Method 2
receive light reflected by the MEMS. When sound waves drive the diaphragm of the MEMS, the diaphragm vibrates slightly, thereby changing the intensity and the phase of light reflected back
Data Source
AI summary
A microphone chip and a microphone. The microphone chip includes: a base including an inner cavity; a diaphragm including a diaphragm inner part and a diaphragm outer part that are connected to the diaphragm inner part, the diaphragm being supported on the base by means of the diaphragm outer part, and the diaphragm inner part being arranged to be opposite to the inner cavity; and a limiting member supported on the base and located at two opposite sides of the diaphragm along a vibration direction of the diaphragm, the limiting member being spaced apart from the diaphragm, and the limiting member being configured to limit an amplitude of the diaphragm inner part. When the diaphragm inner part moves to a certain displacement, the limiting member can limit further movement of the diaphragm inner part, thereby reducing a damage risk caused by excessive displacement of the diaphragm under high sound pressure.