MEMS Microphone Array Capsule for High SNR Audio
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Solution Overview
Problem
Existing MEMS microphones suffer from low signal-to-noise ratio (SNR), low acoustic overload point (AOP), and ultrasonic overload issues due to high-amplitude resonance, limiting their performance in professional audio applications.
Innovation Solution
The proposed MEMS microphone design incorporates an array of MEMS microphone structures with reduced total acoustic resistance, an enlarged sound port to prevent resonant cavities, and advanced electrical components for noise reduction and dynamic range capture, along with a suitable interconnect method for acoustic integration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If MEMS microphone structures are made small for integration, then device size is reduced, but signal-to-noise ratio deteriorates
Solution Approach 1:
The patent divides the microphone diaphragm into multiple independent sensing elements arranged in an array. Each element contributes to the overall signal while independent noise sources tend to average out, improving the signal-to-noise ratio without increasing the total device footprint. This segmentation allows small individual elements to achieve collective performance comparable to larger single elements.
Solution Approach 2:
The patent combines multiple MEMS sensing elements into a single integrated array structure that functions as one unified microphone. The electrical signals from individual elements are combined through summing circuits, achieving improved noise performance and frequency response while maintaining a compact form factor suitable for mobile device integration.
2Stability of the object's composition
If damping is removed to improve frequency response, then frequency response flatness is improved, but acoustic overload point deteriorates
Solution Approach 1:
The patent applies different damping characteristics to different regions of the diaphragm structure. The central region maintains low damping for flat frequency response, while peripheral regions or specific structural elements incorporate damping features to control resonance and prevent ultrasonic overload. This localized approach allows simultaneous optimization of frequency response and overload protection.
Solution Approach 2:
The patent employs composite diaphragm structures combining materials with different mechanical properties. The diaphragm may include layers or regions with varying damping characteristics, allowing the structure to achieve both flat frequency response in the audio range and controlled resonance behavior at ultrasonic frequencies, thereby improving the acoustic overload point.
3Measurement precision
If array size is increased to reduce total acoustic resistance, then signal-to-noise ratio is improved, but device complexity increases
Solution Approach 1:
The patent designs the MEMS array structure to serve multiple functions simultaneously: the individual elements provide noise reduction through spatial averaging, the array geometry controls acoustic impedance, and the integrated electronics handle signal processing. This multi-functionality reduces the need for separate components, thereby managing complexity while achieving improved signal-to-noise ratio.
Solution Approach 2:
The patent implements a nested structure where multiple sensing elements are arranged in a compact, space-efficient configuration within the diaphragm. The elements are positioned to optimize acoustic coupling while minimizing the overall footprint. This nested arrangement allows a larger effective array size for noise reduction without proportionally increasing the device's external dimensions or structural 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
This design improves the SNR and frequency response of MEMS microphones, enhances their suitability for professional audio applications, and reduces noise and frequency response issues by increasing damping and using a larger array to reduce total acoustic resistance.
Implementation Method 1
Each of the MEMS acoustic sensor elements can be tuned to different resonant frequencies
Implementation Method 2
respective ones of the MEMS acoustic sensor elements can be tuned to different resonant frequencies... increases damping and using a larger array to reduce total acoustic resistance
Data Source
AI summary
The present invention relates to a microelectromechanical system (MEMS) microphone array capsule. In one embodiment, a MEMS microphone includes a MEMS microphone die; an acoustic sensor array formed into the MEMS microphone die, the acoustic sensor array comprising a plurality of MEMS acoustic sensor elements, wherein respective ones of the plurality of MEMS acoustic sensor elements are tuned to different resonant frequencies; and an interconnect that electrically couples the acoustic sensor array to an impedance converter circuit.