Piezoelectric Resonator Electrode Openings for Spurious Mode Suppression
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Solution Overview
Problem
Conventional resonators using piezoelectric materials often suffer from spurious modes that couple with the main vibration shape mode, especially in applications with wide operating temperature ranges, leading to unwanted vibrations and affected product characteristics.
Innovation Solution
The resonator design incorporates a vibration plate with first and second electrodes, where at least one of the electrodes features a plurality of openings that are pairwise distributed symmetrically with respect to the electrode's geometric center, and these openings do not contact the electrode's edge, effectively suppressing spurious modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional electrodes without openings are used, then the resonator structure is simple, but spurious modes couple with the main vibration shape mode affecting product characteristics
Solution Approach 1:
The electrode is segmented by introducing multiple openings that divide the continuous electrode structure into separate regions. This segmentation creates distinct vibration zones that suppress spurious modes while maintaining the main thickness shear vibration mode, directly resolving the technical contradiction between spurious mode suppression and structural simplicity.
Solution Approach 2:
The electrode is designed with a porous structure containing multiple openings rather than being solid. This porous configuration allows the electrode to selectively permit certain vibration modes while blocking spurious modes, achieving reliable spurious mode suppression without significantly complicating the overall device structure.
2Reliability
If openings are added to suppress spurious modes, then spurious mode suppression is improved, but manufacturing precision requirements increase
Solution Approach 1:
The openings are arranged in an asymmetric pattern relative to the electrode center, with different positions and dimensions on opposite sides. This asymmetric design breaks the symmetry that would otherwise allow spurious modes to couple with the main vibration mode, achieving effective suppression while using standard manufacturing tolerances.
Solution Approach 2:
The opening pattern is replicated from one electrode to another in the resonator assembly, ensuring consistent spurious mode suppression across multiple components. This copying approach maintains reliability while simplifying manufacturing by using standardized templates for opening placement.
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 design effectively suppresses spurious modes without damaging the main vibration shape mode, maintaining the vibration intensity of the thickness shear vibration mode and improving the resonator's performance, especially in automotive applications with varying temperatures.
Implementation Method 1
the resonator is an electronic device that utilizes the piezoelectric properties of the material and the natural resonance frequency of the material... due to the piezoelectric effect, the voltage between the two electrodes will change with the vibration
Implementation Method 2
When a voltage difference is applied between the two electrodes, the piezoelectric material will deform due to the inverse piezoelectric effect
Implementation Method 3
utilizes the piezoelectric properties of the material and the natural resonance frequency of the material... thickness shear vibration mode
Data Source
AI summary
A resonator including a vibration plate, a first electrode, and a second electrode is provided. The vibration plate has a first surface and a second surface opposite to the first surface. The first electrode is disposed on the first surface, and the second electrode is disposed on the second surface. At least one of the first electrode and the second electrode has a plurality of openings. The openings are pairwise distributed. Each pair of openings are symmetrically distributed with respect to a geometric center of an electrode which the openings belong to. All the openings do not contact with an edge of the electrode which the openings belong to.