MEMS Microphone Packaging With Light Sensing Against Optical Interference
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Solution Overview
Problem
Miniaturized microphones, such as MEMS microphones, are susceptible to light interference which can generate electrical signals that degrade the accuracy of acoustic signal representation, potentially leading to false commands or security breaches, especially in critical applications like voice-controlled devices.
Innovation Solution
Incorporating a light sensor within the MEMS microphone package to detect and process light signals, allowing the processing circuitry to modify the microphone signal and compensate for light-induced noise, thereby enhancing signal accuracy and security.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a MEMS microphone uses an exposed access port to receive acoustic signals, then the microphone can accurately capture voice commands, but light energy can enter through the same port and generate interfering electrical signals
Solution Approach 1:
A light sensor is introduced as an intermediary element to detect light energy before it can interfere with the acoustic signal processing. The light sensor acts as a mediator that monitors the light conditions and enables the processing circuitry to compensate for light-induced interference in the microphone signal
Solution Approach 2:
The system implements feedback by using the light sensor output to continuously monitor light conditions and dynamically adjust the microphone signal processing. The processing circuitry uses the light signal feedback to compensate for light interference in real-time, improving signal accuracy while maintaining the exposed access port configuration
2Reliability
If the microphone package includes additional light sensor components, then light interference can be detected and compensated, but the device complexity increases
Solution Approach 1:
The light sensor is merged with the existing MEMS microphone package structure, integrating multiple functions (acoustic sensing and light detection) into a single unified device. This combining approach allows light interference compensation without requiring a completely separate system, thereby limiting the increase in device 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
The solution effectively mitigates light interference, improving the accuracy of voice command recognition and preventing potential security breaches by dynamically adjusting the microphone signal processing based on light conditions.
Implementation Method 1
a light sensor at a location on an exposed surface of the MEMS microphone package and configured to output a light signal based on light received at the location
Implementation Method 2
a MEMS diaphragm movable in response to a received acoustic signal, and processing circuitry coupled to the MEMS layer... configured to output a microphone signal corresponding to movement of the MEMS diaphragm
Data Source
AI summary
A microelectromechanical system (MEMS) microphone includes a cavity to receive an acoustic signal. The acoustic signal causes movement of a diaphragm relative to one or more other surfaces, which in turn results in an electrical signal representative of the received acoustic signal. A light sensor is included within the packaging of the MEMS microphone such that an output of the light sensor is representative of a light signal received with the acoustic signal. The output of the light sensor is used to modify the electrical signal representative of the received acoustic signal in a manner that limits light interference with an acoustical output signal.