MEMS Resonator Structure for Support Arm Vibration Limiting
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Solution Overview
Problem
Existing resonance devices using micro electro mechanical systems (MEMS) technology face stress issues at the connecting portion between the support arm and the frame due to spurious modes during ultrasonic vibration, which can lead to damage or breakage.
Innovation Solution
A resonance device is designed with a resonator having a base, vibrating arm, frame, and support arm, along with substrates that include recesses and limiting portions to reduce stress at the connecting portion by limiting the vibration amplitude of the support arm.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If ultrasonic vibration is applied to the resonator, then cleaning or welding function is achieved, but the support arm violently vibrates due to spurious mode causing stress concentration at the connecting portion
Solution Approach 1:
The patent applies preliminary action by pre-designing the vibration space with specific dimensional constraints before ultrasonic vibration occurs. The vibration space height is controlled to be 0.05-0.2 times the support arm length, and the vibration space width is controlled to be 0.2-0.5 times the support arm length, which preliminarily suppresses spurious mode vibrations before they can cause damage during ultrasonic cleaning or welding operations
Solution Approach 2:
The patent employs parameter changes by precisely controlling the dimensional parameters of the vibration space. By setting the height to 0.05-0.2 times the support arm length and width to 0.2-0.5 times the support arm length, the patent changes the physical parameters of the vibration environment to suppress spurious modes and reduce stress at the connecting portion while maintaining ultrasonic vibration functionality
2Stress or pressure
If the support arm is made longer to reduce stress, then stress distribution improves, but the vibration amplitude control becomes more difficult and device size increases
Solution Approach 1:
Rather than simply increasing the support arm length, the patent changes the parameters of the vibration space dimensions relative to the support arm length. The height is set to 0.05-0.2 times the support arm length and width to 0.2-0.5 times the support arm length, creating a proportional relationship that controls vibration amplitude and stress distribution simultaneously without unnecessarily increasing overall device size
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 design effectively reduces stress at the connecting portion between the support arm and the frame, thereby preventing damage and enhancing the durability of the resonance device during ultrasonic vibration applications.
Implementation Method 1
a piezoelectric film provided between the first electrode and the second electrode, having an upper surface facing the first electrode, and vibrating in a predetermined vibration mode when a voltage is applied between the first electrode and the second electrode
Implementation Method 2
In such a resonance device, ultrasonic vibration may be applied to the resonator during ultrasonic welding, ultrasonic cleaning, or the like
Data Source
AI summary
A resonance device is provided that includes a resonator having a base, a vibrating arm extending from one end of the base along a first direction, a frame disposed around at least a part of the vibrating arm and holding the vibrating arm such that the vibrating arm is configured to vibrate, and a support arm connecting the base to the frame. Moreover, a first substrate is provided that includes a first recess forming at least a part of a vibration space for the resonator and a first limiting portion provided away from the support arm by a first distance in a thickness direction, in which the first distance is smaller than a distance between a bottom surface of the first recess and the vibrating arm in the thickness direction of the first substrate.