Piezoelectric Vibration Sensor Electrode Arrangement
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Solution Overview
Problem
MEMS-type piezoelectric vibration sensors face challenges in enhancing sensitivity to minute vibrations and achieving adequate sensitivity.
Innovation Solution
The design includes a cantilever structure with a support layer, insulating layer, piezoelectric layer, common electrode, sensing electrode, and drive electrode, where the sensing electrode is positioned near the base to concentrate stress and the drive electrode surrounds the sensing electrode, optimizing electrode sizes and arrangements to enhance sensitivity and resonance frequency identification.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the sensing electrode is positioned near the base of the cantilever structure, then the sensitivity to vibrations is improved, but the device complexity increases due to optimized electrode arrangement
Solution Approach 1:
The sensing electrode is positioned specifically near the base of the cantilever structure where stress concentration occurs during vibration, rather than uniformly distributing electrodes. This localized positioning maximizes the sensing capability at the most critical region, improving vibration detection sensitivity while maintaining a relatively simple overall structure.
2Power
If the drive electrode surrounds the sensing electrode, then the driving performance is improved, but the manufacturing precision requirements increase
Solution Approach 1:
The drive electrode is designed with an asymmetric surrounding configuration that envelops the sensing electrode. This asymmetric arrangement creates an effective driving field that enhances the cantilever's vibration response, improving driving performance while the design accommodates standard manufacturing tolerances.
3Power
If the sensing electrode dimensions are optimized to half the cantilever dimensions, then the output voltage is increased, but the area of the sensing electrode is reduced
Solution Approach 1:
The sensing electrode dimensions are optimized to approximately half the length and width of the cantilever structure. This parameter optimization creates an optimal balance between the electrode area and the stress concentration effect, maximizing the piezoelectric output voltage while maintaining adequate sensing coverage.
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
This configuration increases the output voltage and sensitivity to vibrations, allowing for effective detection and calibration, with optimal sensitivity achieved when the sensing electrode's length and width are half the cantilever structure's dimensions, and the drive electrode's placement enhances driving performance and sensing sensitivity.
Implementation Method 1
MEMS-type piezoelectric vibration sensors face challenges in enhancing sensitivity to minute vibrations
Implementation Method 2
optimizing electrode sizes and arrangements to enhance sensitivity and resonance frequency identification
Data Source
AI summary
A vibration sensor according to an embodiment includes a laminated body. The laminated body includes a support layer a first end of which is fixed; a piezoelectric layer on the support layer; an insulating layer disposed between the support layer and the piezoelectric layer; a common electrode disposed on a first principal surface of the piezoelectric layer; a first sensing electrode disposed in a first area on a second principal surface of the piezoelectric layer on the side opposite to the first principal surface; and a drive electrode disposed in a second area different from the first area on the second principal surface of the piezoelectric layer. The first area is located near the first end of the support layer.