MEMS Microphone Array for Acoustic Camera Noise Visualization

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Solution Overview

Problem

Existing acoustic camera systems using conventional measurement microphones are expensive, complex, and costly, requiring over 30 microphones and extensive data measurement apparatus, making them unsuitable for widespread adoption and efficient manufacturing.

Innovation Solution

The use of MEMS microphones mounted on a printed circuit board to form a microphone array, which includes a data collection unit to digitize analog signals, a central processing unit to calculate noise levels, and a display unit to visualize noise distribution, enabling a more cost-effective and efficient acoustic sensor apparatus and camera system.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional measurement microphones are used to build an acoustic camera system, then measurement precision and sound field visualization capability are improved, but device complexity and manufacturing cost increase significantly

Engineering Contradiction:
Improvesound field visualization capabilityVSAvoidsystem complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces expensive conventional measurement microphones with inexpensive MEMS microphones that can be mass-produced. Although MEMS microphones are smaller and less robust individually, their low cost allows deploying arrays of 30+ units without significantly increasing system cost, thereby maintaining measurement precision while reducing device complexity

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent changes the physical parameters of the microphone system by transitioning from large conventional microphones to small MEMS microphones. This parameter change enables compact array configurations that reduce overall system complexity while maintaining adequate spatial sampling for acoustic camera functionality

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If conventional measurement microphones are used to build an acoustic camera system, then measurement precision is improved, but manufacturing cost and production time increase

Engineering Contradiction:
Improvesound field visualization capabilityVSAvoidmanufacturing cost
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

The patent adopts MEMS microphones which are manufactured using semiconductor fabrication processes, enabling mass production at low cost. This principle directly addresses the manufacturing cost issue by replacing expensive conventional microphones with cheap, mass-producible MEMS devices that maintain adequate measurement precision for acoustic camera applications

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent leverages the universality of MEMS microphone technology, which was originally developed for consumer electronics like mobile phones. This multi-functional component serves both consumer electronics and acoustic measurement applications, reducing development costs and enabling standard manufacturing processes to be applied

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Measurement precision

If conventional measurement microphones are used to build an acoustic camera system, then sound field visualization capability is improved, but device weight and size increase

Engineering Contradiction:
Improvesound field visualization capabilityVSAvoiddevice weight
Core Design Contradiction:
Measurement precisionVSWeight of moving object

Solution Approach 1:

The patent fundamentally changes the physical scale parameter by using MEMS microphones that are orders of magnitude smaller than conventional measurement microphones. This parameter change allows the acoustic camera system to achieve adequate spatial sampling with a compact array, dramatically reducing device weight and size while maintaining sound field visualization capability

Inventive Principle:
Principle #35Parameter changes

4Measurement precision

If conventional measurement microphones are used to build an acoustic camera system, then sound field visualization capability is improved, but production time and manufacturing complexity increase

Engineering Contradiction:
Improveacoustic measurement capabilityVSAvoidproduction efficiency
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The patent uses inexpensive MEMS microphones that can be quickly assembled into arrays using standard PCB mounting techniques. This approach eliminates the need for complex calibration and setup procedures required by expensive conventional microphones, significantly improving production efficiency and reducing manufacturing time

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent employs identical MEMS microphone units throughout the array, all manufactured using the same semiconductor fabrication process. This copying approach simplifies manufacturing by using standardized components that can be mass-produced and quickly assembled, eliminating the need for custom fabrication of each microphone unit

Inventive Principle:
Principle #26Copying

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 solution reduces production costs and time, allows for a more compact and lightweight design, and improves reflection wave removal capabilities, making the acoustic camera system more market-friendly and competitive.

Implementation Method 1

The MEMS microphone senses capacitive change according to sound pressure which is inputted when uniform DC bias voltage is applied between a vibration plate and a reference plate

Methodology Applied
Scientific EffectCapacitive change detection: Capacitance

Data Source

PatentEP2746737B1Acoustic sensor apparatus and acoustic camera using a MEMS microphone array
Publication Date: 2021.11.24 SM INSTRUMENTS CO LTD
  • EP2746737B1 patent drawingFigure 1
  • EP2746737B1 patent drawingFigure 2
  • EP2746737B1 patent drawingFigure 3

AI summary

The present invention discloses an acoustic camera for using a MEMS microphone array comprising: an acoustic sensor apparatus 30 comprising a print circuit board 20 on which the plural of MEMS microphone 10 are mounted, to send signals for the detected sound to a data collection unit 40; a data collection unit 40 connected to the acoustic sensor apparatus 30, which samples analog signals related to sound transmitted from the acoustic sensor apparatus 30 to transform into digital signals and transmit them to the central processing unit 40; a central processing unit 50 connected to the data collection unit 40, which calculates noise level based on digital signals related to sound transmitted from the data collection unit 40; and a display unit 60 which is connected to the central processing unit 50, which displays in color the noise level calculated at the central processing unit.