Piezoelectric Resonator Arm Coupling to Suppress Spurious Modes
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Solution Overview
Problem
Existing resonance devices using MEMS technology suffer from unwanted spurious vibration modes at frequencies near the main vibration frequency, degrading the characteristics of the main vibration.
Innovation Solution
A resonator design featuring a base and multiple vibration arms with piezoelectric substance and electrode layers, where the vibration arms are connected by a connection portion that aligns with the direction of electric field application, preventing spurious modes by ensuring synchronized phase vibration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If vibration arms are configured with opposite phase electric fields to achieve bending vibration, then main vibration is generated, but spurious modes occur at frequencies near the main vibration frequency
Solution Approach 1:
The patent connects vibration arms that bend in the same direction through a connection portion, merging their mechanical behavior. This causes the connected arms to vibrate in the same phase, preventing the generation of spurious modes while maintaining the desired bending vibration mode.
Solution Approach 2:
The patent applies different connection configurations to different vibration arms based on their bending characteristics. Specifically, arms bending in the same direction are connected, while arms bending in opposite directions remain separate, creating localized quality differences that eliminate spurious modes.
2Shape
If vibration arms are spaced apart across a predetermined space, then out-of-plane bending vibration is enabled, but structural complexity increases
Solution Approach 1:
The resonator structure is segmented into distinct components: a base portion, multiple vibration arms spaced apart, and a connection portion. This segmentation allows each component to perform its specific function while maintaining overall structural simplicity and enabling out-of-plane bending vibration.
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 solution effectively inhibits the occurrence of spurious modes, enhancing the characteristics of the main vibration and improving the coupling coefficient, thereby maintaining the resonant frequency stability.
Implementation Method 1
a plurality of vibration arms having a piezoelectric substance and a pair of electrode layers opposing each other with the piezoelectric substance interposed therebetween
Data Source
AI summary
A resonator including a base; two or more vibration arms connected at ends thereof to a front end of the base and spaced apart from each other across a predetermined space and extending away from the base. Moreover, a connection member connects the vibration arms that bend in the same direction when an electric field is applied. The resonator inhibit occurrence of a spurious mode that otherwise occurs in a resonator that performs out-of-plane bending.