Acoustic Sensor Torque Measurement for Directional Detection
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Solution Overview
Problem
Existing microphones, particularly directional ones, face challenges in achieving high directivity and low noise floors due to complex optical readout approaches and alignment issues, which complicate packaging and manufacturing, and require significant power consumption and limited frequency range.
Innovation Solution
The development of an acoustic sensor with a rotatable plate mounted on a substrate using freely rotatable or torsionally deforming mounts, equipped with piezoelectric detectors to measure torque, allowing for multiple axes of rotation and improved signal-to-noise ratio by employing multiple detectors and processing methods to separate and compare their outputs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If optical readout approaches are used for directional microphones, then high directivity and low noise floor are achieved, but packaging and manufacturing complexity increases
Solution Approach 1:
The patent replaces complex optical readout systems with a simplified capacitive sensing mechanism. Instead of using optical components to detect diaphragm motion, the invention employs capacitive sensors that directly measure the position changes of the diaphragm through electrical field interactions, thereby reducing manufacturing complexity while maintaining measurement precision
Solution Approach 2:
The patent extracts and eliminates the optical readout subsystem from the microphone design. By removing optical components and focusing solely on the mechanical-diaphragm-sensor interaction through capacitive sensing, the design achieves high directivity without the packaging and manufacturing complexities associated with optical systems
2Measurement precision
If optical readout approaches are used for directional microphones, then high directivity is achieved, but power consumption increases
Solution Approach 1:
The patent replaces power-intensive optical readout systems with low-power capacitive sensing. The capacitive sensors require minimal power to maintain their electrical fields and detect diaphragm motion, significantly reducing the overall power consumption of the directional microphone system while preserving high directivity performance
3Measurement precision
If multiple sensors are integrated on a single die for co-located pressure gradient measurements, then measurement precision improves, but alignment tolerances become more challenging
Solution Approach 1:
The patent merges multiple capacitive sensors into a single integrated structure where the sensors are formed as part of the same fabrication process. This integration ensures that the sensors are automatically co-located with precise geometric relationships defined by the manufacturing process, eliminating the need for separate alignment steps and reducing alignment tolerance challenges
Solution Approach 2:
The patent designs a universal sensor structure where a single diaphragm serves multiple functions: it acts as the sensing element for pressure gradient measurements while also serving as the mechanical structure that positions the capacitive sensors. This multi-functionality ensures that all sensors are inherently aligned through their common mechanical reference, simplifying manufacturing while maintaining measurement precision
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 acoustic sensor achieves a high signal-to-noise ratio for sound from specific directions, reduces noise floor, and operates over a broad frequency range, enabling efficient directional sound detection with reduced power consumption and simplified manufacturing.
Implementation Method 1
In one embodiment the detectors are piezoelectric sensors
Implementation Method 2
The plate is held in place by springs
Data Source
AI summary
A method of designing and manufacturing an acoustic sensor having a high degree of directivity is disclosed. The sensor includes a rotatable plate that is attached to a substrate with mounts. In one aspect the mounts are freely rotatable and the torque on the plate is measured using detectors disposed on springs that provide a resistance to rotation of the plate. In another aspect the plate is mounted to the substrate with mounts that torsionally deform during rotation of the plate. These detectors measure the torque on the plate according to the torsional deformation of the mounts. Methods of improving the signal to noise ratio of acoustic sensors having multiple detectors are also disclosed.