Acoustic Cavity Vibration Sensor Structure for Stable Signal Detection
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Solution Overview
Problem
Existing vibration sensors suffer from structural instability and low sensitivity, leading to low product yield and performance issues.
Innovation Solution
A vibration sensor design featuring a housing that forms an acoustic cavity divided into two compartments by a vibration unit, with a mass element and elastic element configuration that enhances structural stability and sensitivity by increasing the connection area between the elements, thereby improving sealing and acoustic pressure changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a vibration sensor uses a piezoelectric element to detect vibrations, then the sensor can achieve basic vibration detection functionality, but the sensor becomes susceptible to drift and malfunction in high-temperature environments
Solution Approach 1:
The sensor is divided into two separate functional elements: a piezoelectric element for detecting acceleration forces and a strain gauge element for detecting stress forces. This segmentation allows each element to be optimized for its specific function and compensated for temperature effects independently, improving overall reliability in high-temperature environments.
Solution Approach 2:
A diaphragm serves as an intermediary component that transmits vibrations to both the piezoelectric element and the strain gauge element. The diaphragm acts as a common interface that allows the two sensing elements to measure the same physical phenomenon (vibrations) through different physical mechanisms, enabling temperature compensation.
2Measurement precision
If a vibration sensor relies on a single piezoelectric element, then the device structure remains simple, but the sensor cannot distinguish between acceleration forces and stress forces leading to measurement errors
Solution Approach 1:
The sensor uses two separate sensing elements (piezoelectric element and strain gauge element) positioned at different locations on the diaphragm. The piezoelectric element detects acceleration forces while the strain gauge element detects stress forces. By comparing measurements from both elements, the system can distinguish between different force types and compensate for temperature effects, improving measurement precision.
Solution Approach 2:
The sensor system uses feedback from both the piezoelectric element and strain gauge element to compensate for temperature effects. The strain gauge element provides feedback about temperature-induced stress changes, which is used to correct the measurements from the piezoelectric element, thereby maintaining measurement accuracy in varying temperature conditions.
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 improves structural stability and sensitivity, allowing the sensor to effectively convert vibration signals into electrical signals, particularly in noisy environments, and is suitable for applications like bone conduction microphones and wearable devices.
Implementation Method 1
the sensor includes a piezoelectric element configured to detect acceleration forces generated by vibrations
Implementation Method 2
the sensor includes a strain gauge element configured to detect stress forces generated by vibrations
Data Source
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AI summary
A vibration sensor (200) is provided, comprising: a vibration receiver (210) including a housing (211) and a vibration unit (212), the housing (211) forming an acoustic cavity, the vibration unit (212) being located in the acoustic cavity and separating the acoustic cavity into a first acoustic cavity (213) and a second acoustic cavity (214); and an acoustic transducer (220) acoustically connected to the first acoustic cavity (213). The housing (211) is configured to generate a vibration based on an external vibration signal, the vibration unit (212) changes an acoustic pressure within the first acoustic cavity (213) in response to the vibration of the housing (211), causing the acoustic transducer (220) to generate an electrical signal. The vibration unit (212) includes a quality element (2121) and an elastic element (2122), an area of the quality element (2121) on a side away from the acoustic transducer (220) is smaller than an area of the quality element (2121) on a side close to the acoustic transducer. The elastic element (2122) is connected around a side wall of the quality element (2121).