Piezoelectric Capacitive Hybrid Vibration Sensor Design
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Solution Overview
Problem
Existing vibration sensors and microphones face challenges with low sensitivity and inefficient space utilization due to the uneven strain distribution in piezoelectric vibration sensors, particularly with counterweights, leading to reduced output voltage and wasted space.
Innovation Solution
A vibration sensor and microphone design that combines a piezoelectric system with a capacitive system, where the piezoelectric sensing component is positioned in high-output regions and the capacitive sensing component is placed in low-output regions, utilizing the counterweight area to enhance overall signal strength without affecting the piezoelectric output, thereby improving sensitivity and space utilization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a piezoelectric vibration sensor uses a counterweight to enhance sensitivity, then the output voltage in high-strain regions is improved, but the output voltage in the counterweight region is reduced and space utilization is wasted
Solution Approach 1:
The patent combines a piezoelectric sensing component and a capacitive sensing component into a single integrated sensor structure. The piezoelectric component is positioned in the high-strain region for voltage output, while the capacitive component is positioned in the counterweight region to sense displacement, merging two sensing mechanisms into one unified device that utilizes all available space effectively.
Solution Approach 2:
The sensor structure achieves multi-functionality by having the piezoelectric component detect strain-induced voltage changes and the capacitive component detect displacement changes simultaneously. This allows the single sensor to provide multiple sensing functions, maximizing the utility of each region of the vibration sensor.
2Measurement precision
If only a piezoelectric sensing component is used, then the sensor structure is simple, but the overall signal strength is insufficient and sensitivity is limited
Solution Approach 1:
The patent merges piezoelectric and capacitive sensing mechanisms into a single integrated sensor, allowing both sensing modes to operate simultaneously. This combination enhances the overall signal strength by utilizing both the voltage output from piezoelectric strain and the displacement output from capacitive changes, while maintaining a unified sensor structure rather than separate devices.
Solution Approach 2:
The sensor employs local quality differentiation by positioning the piezoelectric sensing component in the high-strain region where mechanical stress is concentrated, and positioning the capacitive sensing component in the counterweight region where displacement occurs. Each component is optimized for its specific location, maximizing the signal output from each sensing mechanism.
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 combined system increases the overall electrical signal output strength, enhances sensitivity, and reduces device size by effectively utilizing space, while maintaining the high output voltage of the piezoelectric system.
Implementation Method 1
a piezoelectric sensing component, connected to the vibration component and configured to convert the target deformation to a first electrical signal
Implementation Method 2
a capacitive sensing component, connected to the fixed substrate and the vibration component, and configured to convert a distance change between the fixed substrate and the vibration component caused by the target displacement to a second electrical signal
Data Source
AI summary
A vibration sensor and a microphone are provided. The vibration sensor includes a piezoelectric system and a capacitive system. The piezoelectric system includes a vibration component and a piezoelectric sensing component collecting a first electrical signal generated due to deformation of the vibration component. The capacitive system uses the vibration component in the piezoelectric system as a movable capacitive plate and a fixed substrate opposite to the vibration component to form a capacitive vibration sensor. The deformation of the vibration component changes a distance between the vibration component and the fixed substrate. A capacitive sensing component collects a second electrical signal generated due to the distance change. The capacitive sensing component is disposed in a region where the first electrical signal in the piezoelectric system is low, thereby better using space of the vibration sensor, and enhancing the second electrical signal without affecting output of the first electrical signal.