Directional Vibration Sensor Structure for Interference Rejection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Vibration sensors, such as bone conduction microphones, are susceptible to interference from non-target vibration signals, which degrade the effectiveness of sound transmission.
Innovation Solution
A vibration sensor design featuring a housing structure, acoustic transducer, and vibration unit with elastic and mass elements that enhance sensitivity in a specific direction by aligning the centroid of the elastic element with the center of gravity of the mass element, reducing sensitivity to perpendicular vibrations, and using symmetrically distributed elastic elements to improve direction selectivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the vibration sensor uses a simple structure without direction selectivity, then the device complexity is reduced, but the sensor cannot distinguish target vibration signals from non-target signals, leading to interference and reduced measurement precision
Solution Approach 1:
The vibration sensor is segmented into distinct functional components: a housing structure, a vibration unit with mass element and elastic element, and an acoustic transducer. This segmentation allows each component to perform its specific function while contributing to the overall direction selectivity without requiring complex integrated designs.
Solution Approach 2:
The elastic element is configured with specific local properties (elasticity and geometry) that enable it to respond preferentially to vibrations in certain directions. The mass element is positioned and shaped to create differential sensitivity to vibrations along different axes, achieving direction selectivity through localized structural characteristics rather than overall system complexity.
2Ease of manufacture
If the vibration sensor structure is simplified, then the ease of manufacture is improved, but the ability to reduce interference from non-target vibration signals deteriorates
Solution Approach 1:
By dividing the sensor into separate manufacturable components (housing, vibration unit, transducer), each part can be manufactured using standard processes and then assembled, maintaining ease of manufacture while achieving the complex function of interference reduction through the coordinated arrangement of these simple components.
Solution Approach 2:
The harmful non-target vibration signals are effectively extracted or filtered out by the directional sensitivity mechanism. The structure is designed to respond only to vibrations from specific directions, automatically excluding interference from other directions without requiring active filtering or complex signal processing.
3Reliability
If the vibration sensor lacks differential sensitivity to different vibration directions, then the device complexity is reduced, but the sound transmission quality deteriorates due to inability to amplify target signals while minimizing non-target vibrations
Solution Approach 1:
The vibration unit employs local quality differentiation through the elastic element's specific geometry and material properties, creating regions with different mechanical responses. This allows the structure to naturally amplify target vibrations while attenuating non-target vibrations based on their direction, achieving reliable sound transmission without complex active control systems.
Solution Approach 2:
The vibration unit is designed with dynamic characteristics that enable it to respond differently to vibrations depending on their direction and frequency. The mass element and elastic element create a dynamic system with specific resonant properties that enhance target signals while suppressing interference, achieving reliable sound transmission through dynamic behavior rather than static structural 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 design enhances the sensor's ability to selectively capture target vibration signals while minimizing interference from non-target signals, improving sound transmission quality.
Implementation Method 1
a ratio of a resonant frequency of vibrations of the vibration unit in the second direction to a resonant frequency of vibrations of the vibration unit in the first direction may be larger than or equal to 2
Implementation Method 2
the acoustic transducer may generate an electrical signal based on the volume change of the first acoustic cavity
Data Source
AI summary
One or more embodiments of the present disclosure provide a vibration sensor. The vibration sensor may include a housing structure, an acoustic transducer, and a vibration unit. The acoustic transducer may be physically connected to the housing structure. An acoustic cavity may be formed at least partially by the housing structure and the acoustic transducer. The vibration unit may be configured to divide the acoustic cavity into a plurality of acoustic cavities. The plurality of acoustic cavities may include a first acoustic cavity. The first acoustic cavity may be in acoustic communication with the acoustic transducer. The vibration unit may include an elastic element and a mass element. The elastic element and the mass element may be located in the acoustic cavity, and the mass element may be connected to the housing structure or the acoustic transducer through the elastic element.