MEMS Microphone Blockage Detection via Signal Analysis

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Solution Overview

Problem

Conventional MEMS microphones in consumer electronic devices are prone to blockage due to small audio ports, leading to decreased quality and performance, as they can be obstructed by user interference, foreign materials, or other objects.

Innovation Solution

A system comprising a microelectromechanical systems (MEMS) acoustic sensor and a processor that detects blockage conditions by analyzing changes in frequency response, using test signals, or proximity sensors to determine obstructions within the audio port, thereby improving the microphone's performance and accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If the audio port size is reduced to meet device miniaturization requirements, then the device size is reduced, but the audio port becomes prone to blockage

Engineering Contradiction:
Improvedevice sizeVSAvoidaudio port blockage resistance
Core Design Contradiction:
Volume of moving objectVSReliability

Solution Approach 1:

The system performs preliminary blockage detection by analyzing acoustic signals before they significantly degrade microphone performance. The processor continuously monitors the audio port condition and identifies blockages early, enabling preventive actions such as alerting the user or switching to alternative audio paths before the blockage causes quality issues.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system implements feedback by analyzing the acoustic signals received by the MEMS microphone and comparing them against expected characteristics. When deviations indicating blockage are detected, the system provides feedback through user notifications or system adjustments, creating a closed-loop monitoring system that maintains audio quality despite small port dimensions.

Inventive Principle:
Principle #23Feedback

2Reliability

If blockage detection and mitigation features are added, then the quality and performance are maintained, but the device complexity increases

Engineering Contradiction:
Improvemicrophone performance stabilityVSAvoidsystem complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The existing MEMS microphone and processor are made multi-functional by adding blockage detection capabilities to their existing audio signal processing functions. The same hardware components that capture audio signals also detect blockages by analyzing signal characteristics, eliminating the need for separate dedicated detection hardware and reducing overall system complexity.

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

Solution Approach 2:

The MEMS microphone system performs self-diagnosis by autonomously analyzing its own received acoustic signals for blockage conditions. The processor embedded in the microphone device independently evaluates signal characteristics and detects blockages without requiring external monitoring systems, enabling the device to self-monitor and self-report its operational status.

Inventive Principle:
Principle #25Self-service

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 system effectively detects and mitigates blockage conditions, enhancing the quality and performance of MEMS microphones by identifying changes in acoustic signal characteristics or using test signals to assess port obstructions, thus maintaining optimal operation.

Implementation Method 1

receiving an acoustic signal via an opening of a cavity that encloses a MEMS acoustic sensor

Methodology Applied
Scientific EffectAcoustic signal reception: Sound

Data Source

PatentUS9924288B2Blockage detection for a microelectromechanical systems sensor
Publication Date: 2018.03.20 INVENSENSE INC
  • US9924288B2 patent drawing
  • US9924288B2 patent drawing
  • US9924288B2 patent drawing

AI summary

Systems and techniques for detecting blockage associated with a microelectromechanical systems (MEMS) microphone of a device are presented. The device includes a MEMS acoustic sensor and a processor. The MEMS acoustic sensor is contained in a cavity within the device. The processor is configured to detect a blockage condition associated with an opening of the cavity that contains the MEMS acoustic sensor.