MEMS Acoustic Sensor Directionality via Dipole-Omni Signal Merging
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Solution Overview
Problem
Traditional omnidirectional and directional acoustic sensors face challenges in achieving consistent directionality patterns across different frequencies, and existing methods to convert dipole sensors to cardioid patterns often result in frequency-dependent performance.
Innovation Solution
An acoustic sensor device with multiple MEMS transducers, each having distinct directionality patterns, is packaged such that one transducer exhibits a dipole pattern and another an omnidirectional pattern, allowing for selective output and combination of signals to generate desired directionality patterns like cardioid, hyper-cardioid, or super-cardioid without frequency dependence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If acoustic delay element packaging is used to convert dipole sensor to cardioid pattern, then directionality pattern is improved, but frequency stability deteriorates
Solution Approach 1:
The patent combines multiple sensing elements with different directionality patterns (dipole and omnidirectional) within a single device. By merging these different sensing patterns and processing their signals electronically, the device achieves stable cardioid and other directional patterns across frequencies without relying on frequency-dependent acoustic delay elements.
Solution Approach 2:
The patent replaces the mechanical/acoustic delay element approach with an electronic signal processing system. Instead of using physical acoustic paths with different lengths to create time delays, the device uses electronic processing to combine signals from multiple sensing elements, achieving frequency-stable directionality patterns.
2Adaptability or versatility
If multiple separate sensors are used to achieve different directionality patterns, then directionality control is improved, but device complexity increases
Solution Approach 1:
The patent merges multiple sensing elements with different directionality patterns into a single integrated device package. This allows the device to provide multiple directionality patterns (omnidirectional, cardioid, super-cardioid, etc.) through electronic signal combination rather than requiring separate physical sensor devices, thereby reducing overall system complexity while maintaining versatility.
Solution Approach 2:
The patent creates a universal sensing device that can perform multiple directionality functions through a single package containing multiple sensing elements. The device can selectively output different directionality patterns based on which sensing elements are activated and how their signals are combined, providing multi-functionality without requiring separate specialized sensors for each pattern.
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 device provides stable directionality patterns across frequencies by combining dipole and omnidirectional outputs, reducing the need for multiple sensors and ports, and enhancing sensitivity to desired sound directions while rejecting undesired sounds.
Implementation Method 1
one or more microelectromechanical system (MEMS) transducers supported by the substrate and packaged in the package
Implementation Method 2
Traditional omnidirectional acoustic sensors (e.g., microphones) measure the pressure of incoming sound
Data Source
AI summary
An acoustic sensor device comprises a package, a substrate disposed in the package or forming a part of the package, and one or more microelectromechanical system (MEMS) transducers supported by the substrate and packaged in the package. The one or more MEMS transducers include a plurality of sensing elements including at least a first sensing element and a second sensing element. The one or more MEMS transducers are positioned in the package such the first sensing element exhibits a first directionality pick-up pattern with respect to sound waves traveling in an ambient environment of the acoustic sensor device and the second sensing element exhibits a second directionality pick-up pattern with respect to the sound waves traveling in the ambient environment of the acoustic sensor device. The second directionality pick-up pattern is different from the first directionality pick-up pattern.