Multi-Arm Resonator Layout for Stable Resonant Frequency
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Resonators in MEMS devices experience variations in resonant frequency due to Coulomb forces caused by charges on insulators or conductors, which are not adequately addressed in existing configurations, particularly in designs with vibrating arms that vibrate with opposite phases.
Innovation Solution
A resonator design featuring at least three vibrating arms with a piezoelectric film and electrodes, where the mass-adding portions are spaced further apart than the arm portions, and the arms vibrate with opposite phases, reducing the impact of Coulomb forces on resonant frequency while maintaining mechanical strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If mass-adding portions are positioned close to arm portions to improve mechanical strength, then structural integrity is enhanced, but Coulomb forces from charges on insulators or conductors cause variations in resonant frequency
Solution Approach 1:
The patent applies asymmetry by positioning mass-adding portions at specific locations on vibrating arms where they do not closely approach adjacent arms during vibration. This asymmetric placement reduces Coulomb forces between neighboring arms while maintaining sufficient mechanical strength, thereby stabilizing resonant frequency without compromising structural integrity.
2Area of stationary object
If vibrating arms are positioned close together to reduce device size, then miniaturization is achieved, but Coulomb forces between adjacent arms cause resonant frequency variations
Solution Approach 1:
The patent applies local quality by designing specific regions on the vibrating arms with different characteristics. The mass-adding portions are strategically positioned to create local variations in mass distribution that reduce Coulomb interactions between adjacent arms, while other regions maintain close spacing for miniaturization. This localized differentiation allows small device size while stabilizing resonant frequency.
3Adaptability or versatility
If insulators or conductors are added to vibrating arms to improve functionality, then device capabilities are enhanced, but charges on these materials generate Coulomb forces that vary resonant frequency
Solution Approach 1:
The patent converts the harmful effect of charges on insulators or conductors into a beneficial outcome. By strategically positioning mass-adding portions, the design allows these charged materials to be present for functional purposes while the mass distribution configuration minimizes Coulomb force impacts on resonant frequency, effectively transforming a potential problem into an acceptable solution.
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 variations in resonant frequency and improves vibration characteristics without compromising mechanical strength, even in configurations where inner and outer vibrating arms have different release widths.
Implementation Method 1
a piezoelectric film and an upper electrode and a lower electrode that are provided so as to face each other with the piezoelectric film interposed therebetween
Implementation Method 2
when an insulator or conductor provided on a surface or between layers becomes charged due to ion beam sputtering or the pyroelectric effect, an attractive or repulsive force may act on the resonator due to Coulomb forces and consequently the resonant frequency of the resonator may vary
Implementation Method 3
a mass-adding portion that is connected to a tip of the arm portion and has a larger width than the arm portion
Data Source
AI summary
A resonator includes a base; and at least three vibrating arms having first ends connected to a front end of the base and second ends that are open ends spaced away from the front end. Each vibrating arm includes an arm portion having a part that extends from the fixed end in a direction toward the open end with a constant width and a mass-adding portion that is connected to a tip of the arm portion and has a larger width than the arm portion. An interval between the mass-adding portions is larger than an interval between the arm portions for any two vibrating arms that are adjacent to each other.